Tracheal Intubation During Adult In-Hospital Cardiac Arrest and Survival.

Key Points

Question  Is tracheal intubation during adult in-hospital cardiac arrest associated with survival?

Findings  In a study of 86 628 adults with in-hospital cardiac arrest using a propensity-matched cohort, tracheal intubation within the first 15 minutes was associated with a significantly lower likelihood of survival to hospital discharge compared with not being intubated (16.3% vs 19.4%, respectively).

Meaning  These findings do not support early tracheal intubation for adult in-hospital cardiac arrest.


Importance  Tracheal intubation is common during adult in-hospital cardiac arrest, but little is known about the association between tracheal intubation and survival in this setting.

Objective  To determine whether tracheal intubation during adult in-hospital cardiac arrest is associated with survival to hospital discharge.

Design, Setting, and Participants  Observational cohort study of adult patients who had an in-hospital cardiac arrest from January 2000 through December 2014 included in the Get With The Guidelines–Resuscitation registry, a US-based multicenter registry of in-hospital cardiac arrest. Patients who had an invasive airway in place at the time of cardiac arrest were excluded. Patients intubated at any given minute (from 0-15 minutes) were matched with patients at risk of being intubated within the same minute (ie, still receiving resuscitation) based on a time-dependent propensity score calculated from multiple patient, event, and hospital characteristics.

Exposure  Tracheal intubation during cardiac arrest.

Main Outcomes and Measures  The primary outcome was survival to hospital discharge. Secondary outcomes included return of spontaneous circulation (ROSC) and a good functional outcome. A cerebral performance category score of 1 (mild or no neurological deficit) or 2 (moderate cerebral disability) was considered a good functional outcome.

Results  The propensity-matched cohort was selected from 108 079 adult patients at 668 hospitals. The median age was 69 years (interquartile range, 58-79 years), 45 073 patients (42%) were female, and 24 256 patients (22.4%) survived to hospital discharge. Of 71 615 patients (66.3%) who were intubated within the first 15 minutes, 43 314 (60.5%) were matched to a patient not intubated in the same minute. Survival was lower among patients who were intubated compared with those not intubated: 7052 of 43 314 (16.3%) vs 8407 of 43 314 (19.4%), respectively (risk ratio [RR] = 0.84; 95% CI, 0.81-0.87; P < .001). The proportion of patients with ROSC was lower among intubated patients than those not intubated: 25 022 of 43 311 (57.8%) vs 25 685 of 43 310 (59.3%), respectively (RR = 0.97; 95% CI, 0.96-0.99; P < .001). Good functional outcome was also lower among intubated patients than those not intubated: 4439 of 41 868 (10.6%) vs 5672 of 41 733 (13.6%), respectively (RR = 0.78; 95% CI, 0.75-0.81; P < .001). Although differences existed in prespecified subgroup analyses, intubation was not associated with improved outcomes in any subgroup.

Conclusions and Relevance  Among adult patients with in-hospital cardiac arrest, initiation of tracheal intubation within any given minute during the first 15 minutes of resuscitation, compared with no intubation during that minute, was associated with decreased survival to hospital discharge. Although the study design does not eliminate the potential for confounding by indication, these findings do not support early tracheal intubation for adult in-hospital cardiac arrest.


Generation of mature T cells from human hematopoietic stem and progenitor cells in artificial thymic organoids

Studies of human T cell development require robust model systems that recapitulate the full span of thymopoiesis, from hematopoietic stem and progenitor cells (HSPCs) through to mature T cells. Existing in vitro models induce T cell commitment from human HSPCs; however, differentiation into mature CD3+TCR-αβ+ single-positive CD8+ or CD4+ cells is limited. We describe here a serum-free, artificial thymic organoid (ATO) system that supports efficient and reproducible in vitrodifferentiation and positive selection of conventional human T cells from all sources of HSPCs. ATO-derived T cells exhibited mature naive phenotypes, a diverse T cell receptor (TCR) repertoire and TCR-dependent function. ATOs initiated with TCR-engineered HSPCs produced T cells with antigen-specific cytotoxicity and near-complete lack of endogenous TCR Vβ expression, consistent with allelic exclusion of Vβ-encoding loci. ATOs provide a robust tool for studying human T cell differentiation and for the future development of stem-cell-based engineered T cell therapies.

Evolocumab and Clinical Outcomes in Patients with Cardiovascular Disease.


Evolocumab is a monoclonal antibody that inhibits proprotein convertase subtilisin–kexin type 9 (PCSK9) and lowers low-density lipoprotein (LDL) cholesterol levels by approximately 60%. Whether it prevents cardiovascular events is uncertain.


We conducted a randomized, double-blind, placebo-controlled trial involving 27,564 patients with atherosclerotic cardiovascular disease and LDL cholesterol levels of 70 mg per deciliter (1.8 mmol per liter) or higher who were receiving statin therapy. Patients were randomly assigned to receive evolocumab (either 140 mg every 2 weeks or 420 mg monthly) or matching placebo as subcutaneous injections. The primary efficacy end point was the composite of cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, or coronary revascularization. The key secondary efficacy end point was the composite of cardiovascular death, myocardial infarction, or stroke. The median duration of follow-up was 2.2 years.


At 48 weeks, the least-squares mean percentage reduction in LDL cholesterol levels with evolocumab, as compared with placebo, was 59%, from a median baseline value of 92 mg per deciliter (2.4 mmol per liter) to 30 mg per deciliter (0.78 mmol per liter) (P<0.001). Relative to placebo, evolocumab treatment significantly reduced the risk of the primary end point (1344 patients [9.8%] vs. 1563 patients [11.3%]; hazard ratio, 0.85; 95% confidence interval [CI], 0.79 to 0.92; P<0.001) and the key secondary end point (816 [5.9%] vs. 1013 [7.4%]; hazard ratio, 0.80; 95% CI, 0.73 to 0.88; P<0.001). The results were consistent across key subgroups, including the subgroup of patients in the lowest quartile for baseline LDL cholesterol levels (median, 74 mg per deciliter [1.9 mmol per liter]). There was no significant difference between the study groups with regard to adverse events (including new-onset diabetes and neurocognitive events), with the exception of injection-site reactions, which were more common with evolocumab (2.1% vs. 1.6%).


In our trial, inhibition of PCSK9 with evolocumab on a background of statin therapy lowered LDL cholesterol levels to a median of 30 mg per deciliter (0.78 mmol per liter) and reduced the risk of cardiovascular events. These findings show that patients with atherosclerotic cardiovascular disease benefit from lowering of LDL cholesterol levels below current targets.

Detection of Atherosclerotic Inflammation by 68Ga-DOTATATE PET Compared to [18F]FDG PET imaging.


Background Inflammation drives atherosclerotic plaque rupture. Although inflammation can be measured using fluorine-18-labeled fluorodeoxyglucose positron emission tomography ([18F]FDG PET), [18F]FDG lacks cell specificity, and coronary imaging is unreliable because of myocardial spillover.

Objectives This study tested the efficacy of gallium-68-labeled DOTATATE (68Ga-DOTATATE), a somatostatin receptor subtype-2 (SST2)-binding PET tracer, for imaging atherosclerotic inflammation.

Methods We confirmed 68Ga-DOTATATE binding in macrophages and excised carotid plaques. 68Ga-DOTATATE PET imaging was compared to [18F]FDG PET imaging in 42 patients with atherosclerosis.


Results Target SSTR2 gene expression occurred exclusively in “proinflammatory” M1 macrophages, specific 68Ga-DOTATATE ligand binding to SST2 receptors occurred in CD68-positive macrophage-rich carotid plaque regions, and carotid SSTR2 mRNA was highly correlated with in vivo 68Ga-DOTATATE PET signals (r = 0.89; 95% confidence interval [CI]: 0.28 to 0.99; p = 0.02). 68Ga-DOTATATE mean of maximum tissue-to-blood ratios (mTBRmax) correctly identified culprit versus nonculprit arteries in patients with acute coronary syndrome (median difference: 0.69; interquartile range [IQR]: 0.22 to 1.15; p = 0.008) and transient ischemic attack/stroke (median difference: 0.13; IQR: 0.07 to 0.32; p = 0.003). 68Ga-DOTATATE mTBRmax predicted high-risk coronary computed tomography features (receiver operating characteristics area under the curve [ROC AUC]: 0.86; 95% CI: 0.80 to 0.92; p < 0.0001), and correlated with Framingham risk score (r = 0.53; 95% CI: 0.32 to 0.69; p <0.0001) and [18F]FDG uptake (r = 0.73; 95% CI: 0.64 to 0.81; p < 0.0001). [18F]FDG mTBRmax differentiated culprit from nonculprit carotid lesions (median difference: 0.12; IQR: 0.0 to 0.23; p = 0.008) and high-risk from lower-risk coronary arteries (ROC AUC: 0.76; 95% CI: 0.62 to 0.91; p = 0.002); however, myocardial [18F]FDG spillover rendered coronary [18F]FDG scans uninterpretable in 27 patients (64%). Coronary 68Ga-DOTATATE PET scans were readable in all patients.

Conclusions We validated 68Ga-DOTATATE PET as a novel marker of atherosclerotic inflammation and confirmed that 68Ga-DOTATATE offers superior coronary imaging, excellent macrophage specificity, and better power to discriminate high-risk versus low-risk coronary lesions than [18F]FDG. (Vascular Inflammation Imaging Using Somatostatin Receptor Positron Emission Tomography)


We provide gene-, cell-, plaque-, and patient-level data demonstrating that SST2 PET imaging using 68Ga-DOTATATE provides a quantifiable, cell-specific marker of atherosclerotic inflammation that outperforms [18F]FDG in the coronary arteries. Further work is needed to confirm these findings in a larger patient population and to compare imaging with clinical outcomes. 68Ga-DOTATATE PET offers measurement of both generalized atherosclerotic disease activity and detailed information about local plaque functional phenotype to complement multimodal assessments of anatomic, morphologic, and hemodynamic disease severity. This approach, in selected patient populations, has the potential to improve CVD risk prediction, allowing personalized tailoring of therapies aimed to improve clinical outcomes.

Should healthcare professionals breach confidentiality when a patient is unfit to drive? 

While all are deeply sympathetic to the victims of road crashes, it is also important that we practice medicine that is evidence-based and supported by principles of public health. Among the many problems with mandatory reporting of medical conditions relevant to driving is the fact that it simply does not work, whether for epilepsy (1), dementia (2) or obstructive sleep apnoea (3) among other conditions. Indeed, there was less reporting of epilepsy in a state with a mandatory reporting regulation than in a state without one (1). The problem of lack of efficacy is compounded by the potential breach in clinician-patient relationship and trust, which may lead to avoidance of seeking treatment which reduce the risk to drivers and the general public.

The one condition for which further study might be helpful in considering mandatory reporting in terms of scale, relevance and major impact on road safety is that of alcohol and substance misuse and dependence. Worryingly, there is much less research in the biomedical literature on this topic (4), and due consideration would need to be given as to whether current guidelines of relatively long periods of driving cessation in many jurisdictions are appropriate in terms of ensuring congruence between mandatory reporting, effective treatment strategies and a due balance between safety and mobility.

Solutions to reducing the relatively modest impact (in public health terms) of other medical conditions on road safety include public campaigns to remind drivers of their responsibility for monitoring and maintaining their own health as well as following professional advice. This needs to be allied to stringent penalties for driving against appropriate professional advice, as occurred in this tragic case. In addition, it is of concern that traffic medicine occupies such a low or absent profile in medical school curricula (4), and it is important all doctors and related healthcare professionals attain a core competence in assessing medical fitness to drive within their scope of practice.

1. Drazkowski JF, Neiman ES, Sirven JI, McAbee GN, Noe KH. Frequency of physician counseling and attitudes toward driving motor vehicles in people with epilepsy: comparing a mandatory-reporting with a voluntary-reporting state. Epilepsy Behav. 2010 Sep;19(1):52-4.
2. Herrmann N, Rapoport MJ, Sambrook R, Hébert R, McCracken P, Robillard A; Canadian Outcomes Study in Dementia (COSID) Investigators.. Predictors of driving cessation in mild-to-moderate dementia. CMAJ. 2006 Sep 12;175(6):591-5.
3. Elgar NJ, Esterman AJ, Antic NA, Smith BJ. Self-Reporting by Unsafe Drivers Is, with Education, More Effective than Mandatory Reporting by Doctors. J Clin Sleep Med. 2016 Mar;12(3):293-9.
4. Mello MJ, Nirenberg TD, Lindquist D, Cullen HA, Woolard R. Physicians’ attitudes regarding reporting alcohol-impaired drivers. Subst Abus. 2003 Dec;24(4):233-42.
5. Hawley CA, Galbraith ND, deSouza VA. Medical education on fitness to drive: a survey of all UK medical schools. Postgrad Med J. 2008 Dec;84(998):635-8.

Sexually Dimorphic Changes of Hypocretin (Orexin) in Depression.


Hypocretin (orexin) changes were studied in human postmortem brain in depression.

A clear sex-related change was found in the hypothalamic hypocretin-1-immunoreactivity in depression.

A rat depression model did not reflect the changes in the hypocretin system in the human brain in depression.

The stress systems of depressed patients are put into a higher gear by genetic and developmental factors. Over-reaction of these systems to stressful environmental situations makes people vulnerable to depression and suicide. This is the first postmortem study on changes in a relatively novel stress system in depression, consisting of the hypothalamic hypocretin neurons and hypocretin receptors in the prefrontal cortex. A clear sex-related change was found in the hypothalamic hypocretin-1-immunoreactivity in depression. Evaluation of the hypocretin system in a frequently used depression animal model, i.e. chronic unpredictable mild stress rats, did not replicate changes found in the hypocretin systems in the human brain in depression.



Neurophysiological and behavioral processes regulated by hypocretin (orexin) are severely affected in depression. However, alterations in hypocretin have so far not been studied in the human brain. We explored the hypocretin system changes in the hypothalamus and cortex in depression from male and female subjects.


We quantified the differences between depression patients and well-matched controls, in terms of hypothalamic hypocretin-1 immunoreactivity (ir) and hypocretin receptors (Hcrtr-receptors)-mRNA in the anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex. In addition, we determined the alterations in the hypocretin system in a frequently used model for depression, the chronic unpredictable mild stress (CUMS) rat.


i) Compared to control subjects, the amount of hypocretin-immunoreactivity (ir) was significantly increased in female but not in male depression patients; ii) hypothalamic hypocretin-ir showed a clear diurnal fluctuation, which was absent in depression; iii) male depressive patients who had committed suicide showed significantly increased ACC Hcrt-receptor-2-mRNA expression compared to male controls; and iv) female but not male CUMS rats showed a highly significant positive correlation between the mRNA levels of corticotropin-releasing hormone and prepro-hypocretin in the hypothalamus, and a significantly increased Hcrt-receptor-1-mRNA expression in the frontal cortex compared to female control rats.


The clear sex-related change found in the hypothalamic hypocretin-1-ir in depression should be taken into account in the development of hypocretin-targeted therapeutic strategies.


Our study shows, for the first time in postmortem human brain, that hypothalamic hypocretin/orexin is increased in female – but not in male – depressive patients. In addition, there was a diurnal fluctuation in hypothalamic hypocretin-1-ir in the control subjects, which was absent in depression. Moreover, we observed that Hcrt-receptor-mRNA expression showed differences in the ACC and DLPFC depending on age. Male depressive patients who had committed suicide had significantly increased ACC Hcrt-receptor-2-mRNA expression. Our data thus indicate sex-, brain area-, age-, and potentially suicide-related changes in the hypocretin/orexin system in depression. Finally, a significant positive correlation between hypothalamic CRH-mRNA and prepro-hypocretin-mRNA and a significant increase in Hcrt-receptor-1-mRNA expression in the frontal cortex in female – but not male – CUMS rats strengthen the presence of sexually dimorphic hypocretin/orexin system changes in mood disorder.

4.1. Hypocretin-ir in the Hypothalamus in Depression

It should be noted that the increased IOD of hypocretin-ir may indicate an increase in either hypocretin-expressing neuron number (related to the area stained) and/or staining intensity (measured as OD). An increase of either of these parameters indicates an increased expression of hypocretin protein levels. The significantly increased hypocretin-ir in female depressive patients indicates that hypocretin may play a key role in the etiology of depression, which is more prevalent in females than in males (Piccinelli and Wilkinson, 2000). As we have indicated in the Introduction section, studies have found that Hcrt-receptor-1 gene, or a linked locus, may modulate the risk for mood disorders (Rainero et al., 2011) and Hcrt-receptor-1 gene knockout mice showed increased anxiety-like behavior and altered depression-like behaviors (Abbas et al., 2015). One may thus speculate that the higher levels of hypocretin-1-ir in female patients may enhance depressive symptoms. It should be noted that since all the female subjects studied in our study were in their postmenopausal stage, one would not expect to see the hot flash-related hypocretin changes reported earlier (Federici et al., 2016).

The sex difference in the alterations of hypocretin, which happens in the framework of the stress-hypothesis, was further supported by our animal study, showing a significant positive correlation between hypothalamic prepro-hypocretin-mRNA and CRH-mRNA only in female CUMS rats. In view of this, it is of interest to note that the dual Hcrt-receptor antagonist almorexant was found to prevent HPA axis dysregulation caused by CUMS and offers evidence for the possibility that pharmacological blockade of the hypocretin system induces a robust antidepressant-like effect as well as the restoration of the stress-related HPA axis defect (Nollet et al., 2012). It should be noted, however, that other animal models of depression showed different results in terms of changes in the hypocretin system, such as the genetically depressed Wistar-Kyoto male rats, which showed a lower number and size of hypocretin-1 neurons than its control Wistar male rats (Allard et al., 2004). In another genetically depressed rat model, i.e. the Flinders Sensitive Line (FSL), the number of hypothalamic hypocretin-positive neurons was higher in female FSL rats than in the female control rats, i.e. Flinders Resistant Line (FRL) although this publication by Mikrouli et al. offers no data on male rats (Mikrouli et al., 2011). It is a frequent phenomenon that animal models tend to mimic “just a few symptoms rather than a complete psychiatric disorder”. This is a reason to validate the data obtained in animal models on human postmortem material.

We found a clear day-night fluctuation in hypothalamic hypocretin-1-ir in the control subjects, with higher levels at night, which is similar to the pattern reported for lumbar puncture CSF hypocretin-1 levels obtained by continuous in vivo sampling (Salomon et al., 2003). These findings are in agreement with the concept that hypocretin neurons may play a key role in sleep-wake regulation (Saper, 2013), and the absence of the day-night hypocretin-1-ir fluctuation in depression may thus relate to the frequently occurring symptoms of sleep disorders in this condition. It should be noted that in our earlier research we demonstrated a clear diurnal rhythm in the biological clock, the suprachiasmatic nucleus (SCN), for its main neuropeptide, vasopressin, both on the protein level (Hofman et al., 1993) and on the mRNA level (Zhou et al., 2001) in postmortem material, when the patients were grouped according to time of death. Interestingly, a direct projection from the SCN onto the hypocretin neurons was observed in the brains of rat and human (Abrahamson et al., 2001), which indicates that the SCN may directly regulate the function of hypocretin-immunoreactive neurons. Our finding of the absence of a diurnal hypocretin rhythm in depression agrees with our earlier observation of a diminished SCN function in depression (Zhou et al., 2001). Our data (Zhou et al., 2001) and those of others (Li et al., 2013) thus also show that postmortem studies can indeed reflect the day-night fluctuations during life.

It is of interest to note that in rats the maximal activity of the hypocretin system takes place in their active period, i.e. at night (Mileykovskiy et al., 2005 ;Yoshida et al., 2001) Surprisingly, we found the highest hypocretin-1-ir levels in the human hypothalamus at night. However, this observation agrees with two human studies that reported the lowest CSF hypocretin levels during the daytime (Salomon et al., 2003 ;Grady et al., 2006). This means that the nocturnal elevation of hypocretin-1-ir in the hypothalamus is not simply due to a lack of transport or secretion. A similar phenomenon was observed for melatonin, which is also involved in sleep-wake control: in rats, melatonin levels increase during the dark period (their active phase) and decrease during the light period (rest phase) (Gutjahr et al., 2004), while in humans its levels increase during the dark period (rest phase) and decrease during the light period (active phase) (Zeitzer et al., 2007). The possibility that the diurnal regulation systems act in a different way in a diurnal and a nocturnal species (such as rodents) warrants further investigation.

A recent study showed an age-related decline in the number of hypothalamic hypocretin neurons in the range from 0 to 60 years of age in control subjects (Hunt et al., 2015). We did not find such a correlation, but it should be noted that, unlike in the study by others, the control subjects we studied did not contain very young ages.

4.2. PFC Hcrt-receptors in Depression and in Relation to Suicide

Earlier, our group found, with NBB cortex samples (depression patients without suicide), that the ACC seems to be more vulnerable than the DLPFC to alterations in depression-related molecules, such as nitric oxide synthase, gamma-aminobutyric acid and glutamate (Gao et al., 2013 ;Zhao et al., 2012). In our study, with NBB cortex samples, again we observed a trend for lower Hcrt-receptor-1-mRNA expression in the ACC in depression but no changes in Hcrt-receptors in the DLPFC. The novel finding with SMRI cortex samples (containing depressive patients who committed suicide or died of causes other than suicide) that there was a significantly increased Hcrt-receptor-2-mRNA expression in the ACC, but not in the DLPFC, in male MDD patients who had committed suicide is in agreement with previous findings that the ACC is more vulnerable to suicide than the DLPFC (Zhao et al., 2012 ;  Drevets et al., 2008) and that there is a sex difference in the prevalence of suicide (Maguen et al., 2015). Our data concerning increased ACC Hcrt-receptor-2-mRNA expression in male suicide patients are thus interesting, although too limited for a final conclusion. They do represent, however, a strong rationale for further studies on this topic. Finally, the decreased Hcrt-receptor-1-mRNA expression with aging we observed in the DLPFC may at least partly explain the findings that in SMRI cortex samples (younger) both Hcrt-receptors were detectable in ACC and DLPFC, while in the NBB series (older) Hcrt-receptor-1-mRNA expression was only detectable in ACC and Hcrt-receptor-2-mRNA expression was only detectable in the DLPFC.

Some concerns of the present postmortem brain material study should be mentioned. We did not find significant differences in the hypothalamic hypocretin-1-ir expression between MDD and BD patients, which is in accordance with our previous findings for CRH, AVP and OXT and for receptors in the hypothalamus (Bao et al., 2005 ;  Wang et al., 2008), although a final conclusion on this phenomenon should be based upon a larger sample size. Secondly, one of the inherent potential confounding factors in a postmortem study is medication use. However, we do not think that our main conclusions are cofounded by antidepressants, since increased hypothalamic hypocretin-1-ir was only observed in female depressive patients and increased expression of Hcrt-receptor-2-mRNA in the ACC was only observed in male depressive suicides, although all the depressive groups had been on antidepressants. In addition, animal studies showed that benzodiazepines (Panhelainen and Korpi, 2012), haloperidol (Dalal et al., 2003) and fluoxetine (Nollet et al., 2011), taken by the depressive patients in the present study, may inhibit hypocretin neurons and/or decrease hypocretin levels. Therefore, had antidepressants interfered with our measurements, this would have led to an underestimation of the increased hypocretin-1 levels observed in female depressive patients. It is noted that Calegare et al. found that sub-chronic treatment of adult malerats with fluoxetine increased the levels of prepro-hypocretin mRNA in the hypothalamus without affecting the hypocretin-1 CSF levels ( Calegare et al., 2016). In our study, there were 2 out of 10 male depression patients who had taken fluoxetine, while their hypothalamic hypocretin-1-ir levels (IOD: 0.128 and 0.134) were fully within the range of the other male depression patients (IOD range from 0.103 to 0.248, median value 0.166). Finally, it should also be noted that the Hcrt-receptor data are based upon mRNA measurements and have yet to be confirmed on the protein level.

5. Conclusions

A clear sex-related change was found in the hypothalamic hypocretin-1-ir in depression. The CUMS rat depression model did not replicate changes found in the hypocretin systems in the human brain in depression. Since sex-related changes in hypothalamic hypocretin-1-ir expression were observed in depression, this factor should be taken into account in the development of hypocretin-targeted therapeutic strategies.

Work organization and mental health problems in PhD students


One in two PhD students experiences psychological distress; one in three is at risk of a common psychiatric disorder.

The prevalence of mental health problems is higher in PhD students than in the highly educated general population, highly educated employees and higher education students.

Work and organizational context are significant predictors of PhD students’ mental health.


Research policy observers are increasingly concerned about the potential impact of current academic working conditions on mental health, particularly in PhD students. The aim of the current study is threefold. First, we assess the prevalence of mental health problems in a representative sample of PhD students in Flanders, Belgium (N = 3659). Second, we compare PhD students to three other samples: (1) highly educated in the general population (N = 769); (2) highly educated employees (N = 592); and (3) higher education students (N = 333). Third, we assess those organizational factors relating to the role of PhD students that predict mental health status. Results based on 12 mental health symptoms (GHQ-12) showed that 32% of PhD students are at risk of having or developing a common psychiatric disorder, especially depression. This estimate was significantly higher than those obtained in the comparison groups. Organizational policies were significantly associated with the prevalence of mental health problems. Especially work-family interface, job demands and job control, the supervisor’s leadership style, team decision-making culture, and perception of a career outside academia are linked to mental health problems.

Brentuximab vedotin combined with ABVD or AVD for patients with newly diagnosed Hodgkin’s lymphoma: a phase 1, open-label, dose-escalation study.



Roughly 70–80% of patients with advanced stage Hodgkin’s lymphoma are cured with various first-line and second-line treatments, including ABVD, BEACOPP, and stem-cell transplantation. Brentuximab vedotin has shown significant clinical activity, with a manageable safety profile, in patients with relapsed or refractory Hodgkin’s lymphoma. We aimed to assess the safety and early clinical efficacy of this drug as first-line treatment in combination with standard or modified-standard treatment in patients with previously untreated Hodgkin’s lymphoma.


We did a phase 1, open-label, dose-escalation safety study comparing brentuximab vedotin in combination with standard (ABVD) or a modified-standard (AVD) treatment. Patients were enrolled into the groups sequentially. Main entry criteria were newly diagnosed, treatment-naive, CD30-positive patients with Hodgkin’s lymphoma who had histologically confirmed stage IIA bulky disease or stage IIB–IV disease and an Eastern Cooperative Oncology Group performance status of two or less. Patients received doses of 0·6, 0·9, or 1·2 mg/kg brentuximab vedotin by intravenous infusion every 2 weeks with either ABVD (25 mg/m2 doxorubicin, 10 units/m2 bleomycin, 6 mg/m2 vinblastine, and 375 mg/m2 dacarbazine) or AVD (ABVD modified regimen without the inclusion of bleomycin) for up to six cycles. Our primary objectives were to assess the safety profile and establish the maximum tolerated dose (MTD) of brentuximab vedotin in combination with ABVD and AVD. The safety profile and MTD was assessed for the safety population. The study has completed and the final analysis is presented. This study was registered with, number NCT01060904.


Between Jan 29, 2010, and Sept 17, 2012, 51 patients were enrolled and received at least one dose of brentuximab vedotin. The maximum tolerated dose of brentuximab vedotin when combined with ABVD or AVD was not exceeded at 1·2 mg/kg. 21 (95%) of 22 patients given brentuximab vedotin and ABVD achieved complete remission, as did 24 (96%) of 25 patients given brentuximab vedotin and AVD. Adverse events were generally grade 1 or 2; however, an unacceptable number of patients in the brentuximab vedotin and ABVD groups had pulmonary toxic effects (11 [44%] of 25), which exceeded the historical incidence for ABVD alone. No patients experienced pulmonary toxic effects when treated with brentuximab vedotin plus AVD. The most common grade 3 or worse events were neutropenia (20 [80%] of 25 patients in the brentuximab vedotin and ABVD group vs 20 [77%] of 26 patients in the brentuximab vedotin and AVD group), anaemia (five [20%] vs three [12%]), febrile neutropenia (five [20%] vs two [8%]), pulmonary toxic effects (six [24%] vs 0), syncope (three [12%] vstwo [8%]), dyspnoea (three [12%] vs one [4%]), pulmonary embolism (three [12%] vs 0), fatigue (one [4%] each), and leucopenia (one [4%] each). Serious events occured in 41% of all patients (14 [56%] in the brentuximab vedotin and ABVD group and seven [27%] in the brentuximab vedotin and AVD group). Serious events occurring in 10% of patients or more overall were febrile neutropenia (four [16%] in the brentuximab vedotin and ABVD group vs two [8%] in the brentuximab vedotin and AVD group), and, in the brentuximab vedotin and ABVD group only, pulmonary toxic effects (six [24%]).


Brentuximab vedotin should not be given with bleomycin in general or specifically as first-line therapy for patients with treatment naive, advanced stage Hodgkin’s lymphoma. 1·2 mg/kg brentuximab vedotin combined with AVD given every 2 weeks was generally well tolerated by patients. At present, a phase 3 trial comparing brentuximab vedotin plus AVD to ABVD alone is ongoing (, number NCT01712490) and will formally assess whether brentuximab vedotin plus AVD might redefine therapy in treatment-naive patients with Hodgkin’s lymphoma.


Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning. 


Drugs that modulate serotonin (5-HT) synaptic concentrations impact neurogenesis and hippocampal (HPC)-dependent learning. The primary objective is to determine the extent to which psilocybin (PSOP) modulates neurogenesis and thereby affects acquisition and extinction of HPC-dependent trace fear conditioning. PSOP, the 5-HT2A agonist 25I-NBMeO and the 5-HT2A/C antagonist ketanserin were administered via an acute intraperitoneal injection to mice. Trace fear conditioning was measured as the amount of time spent immobile in the presence of the conditioned stimulus (CS, auditory tone), trace (silent interval) and post-trace interval over 10 trials. Extinction was determined by the number of trials required to resume mobility during CS, trace and post-trace when the shock was not delivered. Neurogenesis was determined by unbiased counts of cells in the dentate gyrus of the HPC birth-dated with BrdU co-expressing a neuronal marker. Mice treated with a range of doses of PSOP acquired a robust conditioned fear response. Mice injected with low doses of PSOP extinguished cued fear conditioning significantly more rapidly than high-dose PSOP or saline-treated mice. Injection of PSOP, 25I-NBMeO or ketanserin resulted in significant dose-dependent decreases in number of newborn neurons in hippocampus. At the low doses of PSOP that enhanced extinction, neurogenesis was not decreased, but rather tended toward an increase. Extinction of “fear conditioning” may be mediated by actions of the drugs at sites other than hippocampus such as the amygdala, which is known to mediate the perception of fear. Another caveat is that PSOP is not purely selective for 5-HT2A receptors. PSOP facilitates extinction of the classically conditioned fear response, and this, and similar agents, should be explored as potential treatments for post-traumatic stress disorder and related conditions.


Is it time to reassess current safety standards for glyphosate-based herbicides? 


Use of glyphosate-based herbicides (GBHs) increased ∼100-fold from 1974 to 2014. Additional increases are expected due to widespread emergence of glyphosate-resistant weeds, increased application of GBHs, and preharvest uses of GBHs as desiccants. Current safety assessments rely heavily on studies conducted over 30 years ago. We have considered information on GBH use, exposures, mechanisms of action, toxicity and epidemiology. Human exposures to glyphosate are rising, and a number of in vitro and in vivo studies challenge the basis for the current safety assessment of glyphosate and GBHs. We conclude that current safety standards for GBHs are outdated and may fail to protect public health or the environment. To improve safety standards, the following are urgently needed: (1) human biomonitoring for glyphosate and its metabolites; (2) prioritisation of glyphosate and GBHs for hazard assessments, including toxicological studies that use state-of-the-art approaches; (3) epidemiological studies, especially of occupationally exposed agricultural workers, pregnant women and their children and (4) evaluations of GBHs in commercially used formulations, recognising that herbicide mixtures likely have effects that are not predicted by studying glyphosate alone.


Glyphosate is an active ingredient in a number of commercially available herbicides, including several that are used in concert with genetically modified crops. The herbicidal action of glyphosate derives from its inhibition of a key plant enzyme, 5-enolpyruvylshikimate-3-phosphate synthase, which is involved in the synthesis of aromatic amino acids. Since this enzyme is not present in vertebrates, it has long been believed that glyphosate would not affect non-target species, including humans. However, multiple lines of evidence suggest that this contention is inaccurate.

Methods used in environmental health sciences to examine the potential health effects of chemicals, including pesticides, have undergone substantial changes over the past 30 years. Cutting-edge tools currently employed by federally funded scientists bear little resemblance to the archaic standardised assays required by regulatory agencies and used in formal risk assessments.1 We are concerned that the assays used to assess glyphosate safety, including the toxicity studies requested by the US Environmental Protection Agency (EPA) in 2009, may be insufficient to address the full complement of health effects that could be induced by exposure to glyphosate-based herbicides (GBHs).

In this commentary, we summarise these key findings as well as trends in increased use of GBHs. Since commercial applications of GBHs began four decades ago, their use has diversified and expanded considerably. We offer recommendations on how to reduce significant uncertainties concerning GBH risks.

Glyphosate use has increased since safety evaluations were conducted

Glyphosate was registered in 1974 in the USA as a broad-spectrum contact herbicide to kill weeds in fields prior to the planting of crops. It was also approved for weed control in a variety of non-crop settings. Glyphosate use is the highest of any pesticide in the USA, with rapid increases in use over the last two decades; worldwide estimates of use suggest that enough GBH was applied in 2014 to spray nearly 0.5 kg glyphosate on every hectare of cropland on the planet.2

In addition to their use as weed-control herbicides, GBHs are now used as desiccants prior to harvest3 to accelerate natural drying of seeds. These use patterns are expected to increase glyphosate residue levels in harvested products. Although such effects still need to be evaluated in controlled studies, residues of glyphosate and aminomethylphosphonic acid (AMPA) (the major bioactive metabolite of glyphosate) are now routinely detected in soybeans, wheat, barley, and many other crops and foods.4 ,5

Although GBH use has increased dramatically in the last 10 years, most of the science used in the risk assessment process to support its safety was conducted more than 30 years ago. In the US EPA’s 1993 registration review of GBHs,6 for example, 73% of the almost 300 citations were published prior to 1985; importantly, only 11 were peer-reviewed. A search of PubMed (conducted 6 November 2016) reveals more than 1500 published studies on glyphosate in the last decade alone. It is incongruous that safety assessments of the most widely used herbicide on the planet rely largely on fewer than 300 unpublished, non-peer-reviewed studies while excluding the vast, modern literature on glyphosate effects.

Considering the ∼100-fold increase in GBH use in the last four decades, increased human exposure is almost certain. Unfortunately, no systematic data have tracked changes in glyphosate or AMPA concentrations in human tissues or bodily fluids during this period. For this reason, we recommend that glyphosate and AMPA should be monitored by the US Centers for Disease Control and Prevention (US CDC) in its National Health and Nutrition Examination Survey (NHANES) biomonitoring programme, as well as other biomonitoring programmes around the world. Studies of the general population to evaluate actual exposures via diet (rather than hypothetical inferred exposures), as well as studies in occupationally exposed individuals (eg, pesticide sprayers as well as production workers), are both needed.

Are humans affected by GBHs?

There are few human epidemiology studies examining the impact of glyphosate on human diseases. Unexplained chronic kidney disease has killed thousands of rice farm workers in Sri Lanka7 and sugarcane workers in Central America;8 exposure to herbicides including GBHs has been documented in some of these populations.9 Some epidemiologists have hypothesised that epidemics of chronic kidney disease among male agricultural workers result from the interactions of the herbicide with hard drinking water and associated metals.7 ,9 Others have attributed these health conditions to dehydration.10 Neither explanation is plausible because such plantation work in these regions has been going on for centuries while the epidemic of kidney failure and herbicide use are recent phenomena.

A number of other studies have evaluated the association between exposures to GBHs and other health effects in humans including cancer. In fact, some of the most compelling studies in human populations suggest associations between GBHs and non-Hodgkin lymphoma.11 ,12 Cancer end points will be discussed later in this commentary.

Without appropriate epidemiological and biomonitoring studies, any association between glyphosate and AMPA concentrations found in human tissues and fluids with disease will remain uncertain. Epidemiological studies are urgently needed to augment the ability of risk assessors to draw better conclusions about the safety of GBHs. Such studies should evaluate short-term and long-term health outcomes including DNA damage and cancer.

Recent studies raise new questions about GBH safety

In laboratory animals, glyphosate can disrupt reproductive development in male rats,13 and male and female fish.14 ,15 Studies in fish and the amphibian Xenopus laevis demonstrate that developmental exposures to GBHs induce malformations in craniofacial structures and the brain, although the mechanism underlying these effects is not fully understood.16 ,17 Research from controlled laboratory studies also suggests that GBHs may contribute to liver,18 hepatorenal19–22 and cardiovascular damage;23 ,24 some of these effects may be due to altered ion flux in these tissues.25 GBHs are also recognised to cause serious eye damage based on evaluation of six separate studies.26 Finally, GBH exposures have been shown to induce oxidative stress27 and genotoxicity28 in vitro and in vivo.

In a previous consensus statement, we analysed these data and raised concerns over the setting of ‘safe’ levels of exposure by regulatory agencies around the world;29 other comprehensive reviews of the toxicity literature also provide an excellent overview of the effects of glyphosate and GBHs on a range of end points.30 ,31

Recently, there has been debate over the possibility that glyphosate is an endocrine disruptor.13 ,14 ,32–34 Studies in cell culture showed that glyphosate induces endocrine-mediated effects on end points relevant to toxicity, as well as cell proliferation.32 ,33 In contrast, using their Endocrine Disruptor Screening Program (EDSP), the US EPA’s recent review of glyphosate dismissed statistically significant differences consistent with oestrogenic activity in some assays (eg, altered vitellogenin levels in a fish short-term reproduction assay) because they followed a non-monotonic dose response.35 The final conclusion of the US EPA was that ‘there was no convincing evidence’ that glyphosate interacts with endocrine pathways. Significant criticisms of the EDSP assays have been raised by endocrinologists, and others have expressed concern about the failure of the EPA to acknowledge non-monotonic dose responses, which have been documented for other endocrine disruptors.36 Other agencies including the European Food Safety Authority (EFSA) have used the EDSP data to suggest that there is not sufficient evidence to conclude that glyphosate is an endocrine disruptor, but the 2015 EFSA report does note that ‘signs of endocrine activity… could not be completely ruled out’ in some of these assays.37

In December 2009, the US EPA issued a ‘Glyphosate Final Work Plan (FWP) registration review’38 that identified uncertainties about the toxicity of glyphosate. For example, the EPA announced its plan to require that registrants conduct acute and subchronic neurotoxicity studies as well as an immunotoxicity study. The EPA also acknowledged that AMPA had not been evaluated for ecological risk assessments. Since this testing is supposed to be conducted by the registrants, it is unclear whether testing is underway, will actually be completed, or will be published in the peer-reviewed literature. Thus, additional studies, using state-of-the-art approaches, are needed to better elucidate the effects of glyphosate and GBHs on non-target species. We recommend that scientists and entities independent of the registrants, (eg, the US National Toxicology Program (NTP)) should prioritise glyphosate and GBHs for hazard assessments. In fact, the US EPA also proposed a collaborative research plan with the NTP, which calls for NTP to help provide answers to four research questions: (1) comparisons of the toxicity of glyphosate versus GBH formulations; (2) provide publicly available data on glyphosate’s effects on cancer-related end points; and (3) non-cancer end points; (4) finally, investigate the mechanisms by which glyphosate and GBHs induce toxic and adverse effects.39 Several of these points are addressed further below.

GBHs are chemical mixtures, and may be more toxic than glyphosate alone

GBHs are always used as a mixture of glyphosate plus numerous other so called inert ingredients, which are added to alter the herbicide’s physicochemical properties and enhance its herbicidal action. Some inert ingredients or chemicals are used to enhance the adhesion of glyphosate to plant surfaces (eg, alkyl polyglycosides), whereas others facilitate its penetration of plant cell walls and into plant tissues (eg, ethoxylated tallow amines) to exert its herbicidal effects. Unfortunately, the full list of these chemicals, collectively known as adjuvants or coformulants, is treated as a trade secret by the manufacturers; the composition of GBHs are unknown and available data on the hazards posed by different mixtures remain limited.

Chemical mixtures can have effects that are more potent than the effects of individual ingredients.40 GBHs have been shown to be more toxic than glyphosate.41–44 It also should be noted that some of the studies discussed in the previous section of this review evaluated GBHs, and thus likely reveal effects that may not be observed if studies examined only the active ingredient. These results reveal that GBH safety evaluations focused on glyphosate alone can underestimate toxicity and are insufficient to assess relevance to human and environmental exposures. Although the number of commercial formulations is extensive and will be difficult to study comprehensively, we propose that the most widely applied GBH formulations should be tested in parallel with glyphosate alone.

Is glyphosate a human carcinogen?

Over the last few years, glyphosate has received significant attention by the public as well as regulatory agencies around the world. In the European Union, safety evaluations on glyphosate have recently been conducted by the European Chemicals Agency (ECHA) and EFSA; in the USA, meetings by evaluation committees within the US EPA scheduled for fall 2016 were cancelled so the agency could supplement the panel of experts with additional members who have expertise in epidemiology. In December 2016, an EPA scientific advisory panel was charged with evaluating the human carcinogenic potential of glyphosate only, not GBHs. The conclusions of this panel have not yet been released.

The WHO’s International Agency for Research on Cancer (IARC) working group’s 2015 decision to classify glyphosate as a grade 2A probable human carcinogen followed an extensive review and evaluation of the weight of all available evidence.45 The outcome was driven by: (1) limited human evidence from case–control epidemiology studies, including high-quality studies reporting a link with non-Hodgkin lymphoma;11 ,12 (2) sufficient evidence from unpublished animal studies analysed by the US EPA, which identified an elevated frequency of rare kidney tumours in male mice, hemangiosarcoma in male mice, pancreatic islet-cell adenoma in male rats, and skin tumours and other non-malignant growths in mice and (3) strong mechanistic evidence, such as numerous studies demonstrating that glyphosate is genotoxic and can induce oxidative stress in humans, human cells, non-human mammals and non-mammalian species (data reviewed in depth in ref. 46). Other data from unpublished studies that have been reviewed in the peer-reviewed literature could not be evaluated by IARC because the data were not publicly available; some of these studies also suggest increases in lymphoma in male mice exposed even to the lowest doses evaluated (14.5 mg/kg/day) (see study 13 evaluated in ref. 47).

A joint meeting on pesticides residues (JMPR) in the WHO used the IARC hazard assessment evaluation (eg, concluding that glyphosate is a probable human carcinogen) to establish a safe level of exposure for humans. In their most recent evaluation, JMPR would not exclude the possibility that glyphosate is a human carcinogen, but concluded that it ‘is unlikely to pose a carcinogenic risk to humans from exposure through the diet’.48 The JMPR did not conduct a quantitative assessment to estimate cancer risk at current dietary exposures, and, more crucially, did not evaluate actual dietary exposures in any population.

The IARC classification was made based on an analysis of the entire body of evidence, including the evaluation of GBH (mixtures) and not glyphosate alone, as IARC requires that ‘the body of evidence is considered as a whole…’.49 A 2016 review of the carcinogenic potential of glyphosate by EFSA contrasts with the IARC conclusions.37 EFSA concluded that ‘glyphosate is unlikely to pose a carcinogenic hazard to humans’ but notes that it drew its conclusions based only on studies of glyphosate alone; studies of GBHs were not included in the EFSA assessment. Other agencies in the European Union, including the German Federal Institute for Risk Assessment, have similarly focused on studies of the active ingredient, failing to consider all studies of GBHs.50 Furthermore, the EFSA monograph notes that studies that demonstrate the genotoxicity of glyphosate that were considered by IARC were not considered by EFSA because they did not follow prescribed guidelines for study reporting (eg, good laboratory practices, or GLP);37this argument has also been made to eliminate studies conducted within academia in other risk assessments,1 despite evidence that academic laboratory research can be well designed and properly reported in the absence of GLP.51 Importantly, studies conducted according to GLP (including study 13 evaluated in ref. 47) that suggest causal links between glyphosate and cancer in exposed rodents have been dismissed by agencies including the EPA and EFSA due to speculation about a viral infection in the animal colony, even though no adverse health effects of such an infection have been shown.26

After the release of the IARC and EFSA expert conclusions, there were a number of public discussions and articles written for lay audiences describing how these organisations could come to conflicting results after reviewing the same literature. These discussions revealed that the same literature often was not evaluated: IARC examined studies of GBH and glyphosate whereas EFSA only evaluated studies of glyphosate; IARC examined all studies whereas EFSA gave priority to studies conducted according to GLP. Finally, IARC has strict conflict of interest rules about the experts that serve on its panels, whereas other agencies including EFSA do not exclude experts that have received monetary compensation from chemical manufacturers. There is evidence that the presence of individuals with conflicts of interest on regulatory panels can influence the integrity of decision making.52 ,53

Where does the burden of proof of safety lie?

The EFSA report, evaluating only studies of glyphosate and not GBH mixtures, concluded that there was no evidence to conclude that it is a carcinogen.37 The European Commission has not yet accepted the EFSA conclusion; in 2016, because European Union member states failed to take action against glyphosate, the European Commission extended its approval for its use under certain circumstances for 18 months, giving ECHA this time to review glyphosate’s classification. In the interim, the Commission recommended that an adjuvant, ethoxylated tallow amine, be banned from GBHs; that spraying of public parks, playgrounds and gardens be minimised; and that preharvest uses be minimised.54 It will be up to the individual member states to approve and enforce these recommendations.

In the USA, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA, (7 U.S.C. §136 et seq. (1996))) requires chemical manufacturers to demonstrate that a pesticide will not cause ‘unreasonable adverse effects on the environment’. Although FIFRA allows risks to humans and the environment to be balanced by the benefits of a pesticide’s use, this can only be accomplished if sufficient data are available to support safety. It also can only be accomplished if the full costs of exposure, including costs to human health, are quantified (see ref. 55 for a discussion of the costs of other environmental chemicals).

FIFRA places the burden to demonstrate that a pesticide is safe on the manufacturers and registrants. Yet the knowledge gaps that currently exist preclude the drawing of conclusions that GBHs are safe as currently used. FIFRA provides the US EPA with the means to restrict the use of pesticides, to update registered pesticides (like glyphosate) with new safety information, and to take action when new evidence of adverse environmental or human health effects are reported (7 U.S.C. §136 et seq. (1996)). The studies we have outlined in this commentary, together with the burden of proof for safety on the chemical manufacturer, clearly suggests that such actions are needed.


In this commentary, we have identified factors that heighten concerns over the adequacy of safety assessments, and by extension, permitted levels of exposure to glyphosate and GBHs. These factors include increased use of GBHs on crops and for non-crop weed control, leading to measurable concentrations of glyphosate and AMPA in foodstuffs and likely increases in human exposures. The lack of biomonitoring data and epidemiological studies remain important data gaps. A small number of controlled laboratory studies using contemporary scientific approaches have identified adverse effects of glyphosate and GBHs at much lower doses than those used to make risk assessment decisions. Although there is controversy and debate regarding the carcinogenic and endocrine disrupting potential of these compounds, conclusions such as those drawn by IARC call into question the safety of GBHs beyond ‘reasonable certainty of no harm’. Considering what is now known about glyphosate from studies published over the last three decades, as well as the knowledge gaps that continue to raise concerns, we conclude that current safety standards for GBHs are outdated and may fail to protect public health and the environment.

What is already known

  • Glyphosate is a widely used herbicide, and its use continues to rise

  • Epidemiology studies suggest associations between GBH exposures and adverse health outcomes including chronic kidney disease and some cancers

  • A small number of rodent studies suggest that glyphosate can induce cancers

  • The effects of chemical mixtures can be more toxic than the effects of individual compounds

What this study adds

  • We call for improved biomonitoring of glyphosate and its metabolites in human populations

  • We recommend that hazard assessments using state-of-the-art technical approaches be conducted on glyphosate and GBHs

  • Epidemiological studies examining occupationally exposed workers, pesticide manufacturers, and vulnerable populations are needed

  • After review of all evaluations, we conclude that the current safety standards are outdated and fail to protect public health and the environment.


The authors gratefully acknowledge support from the World Federation of Scientists, which funded travel for many of the authors to attend the 48th Session of the International Seminars on Planetary Emergencies and Associated Events, where work on this manuscript was conducted.


Source: BMJ