Caspase-3 Protects Stressed Organs against Cell Death.

The ability to generate appropriate defense responses is crucial for the survival of an organism exposed to pathogenesis-inducing insults. However, the mechanisms that allow tissues and organs to cope with such stresses are poorly understood. Here we show that caspase-3-knockout mice or caspase inhibitor-treated mice were defective in activating the antiapoptotic Akt kinase in response to various chemical and environmental stresses causing sunburns, cardiomyopathy, or colitis. Defective Akt activation in caspase-3-knockout mice was accompanied by increased cell death and impaired survival in some cases. Mice homozygous for a mutation in RasGAP that prevents its cleavage by caspase-3 exhibited a similar defect in Akt activation, leading to increased apoptosis in stressed organs, marked deterioration of their physiological functions, and stronger disease development. Our results provide evidence for the relevance of caspase-3 as a stress intensity sensor that controls cell fate by either initiating a RasGAP cleavage-dependent cell resistance program or a cell suicide response.

Militarism and Melodrama: The Cultural Work of Combat Death

This essay examines the role of melodrama in the American war film, focusing on three post-WWII examples. The main argument centers on the natural alliance between melodrama and militarism based on a shared intolerance for the notion of death as meaningless and in vain. Both melodrama and military ideology employ elaborate rhetorical and narrative strategies to enfold deaths into larger systems of meaning, such as the nation, or in more personal terms, as a rite of passage. One of the most common narrative devices present in the military melodrama is the death that converts survivors to the values of the virtuous victim. The essay examines the shared conventions and different strategies of the following three films: Sands of Iwo Jima (1949), Platoon (1986), and Top Gun (1986).

Miltefosine induces programmed cell death in Leishmania amazonensis promastigotes

In the current study, we evaluated the mechanism of action of miltefosine, which is the first effective and safe oral treatment for visceral leishmaniasis, in Leishmania amazonensis promastigotes. Miltefosine induced a process of programmed cell death, which was determined by the externalization of phosphatidylserine, the incorporation of propidium iodide, cell-cycle arrest at the sub-G0/G1 phase and DNA fragmentation into oligonucleosome-sized fragments. Despite the intrinsic variation that is detected in Leishmania spp, our results indicate that miltefosine causes apoptosis-like death in L. amazonensis promastigote cells using a similar process that is observed in Leishmania donovani.

An unexpected role of semaphorin3a-neuropilin-1 signaling in lymphatic vessel maturation and valve formation.

RATIONALE: Lymphatic vasculature plays important roles in tissue fluid homeostasis maintenance and in the pathology of human diseases. Yet, the molecular mechanisms that control lymphatic vessel maturation remain largely unknown. OBJECTIVE: We analyzed the gene expression profiles of ex vivo isolated lymphatic endothelial cells to identify novel lymphatic vessel expressed genes and we investigated the role of semaphorin 3A (Sema3A) and neuropilin-1 (Nrp-1) in lymphatic vessel maturation and function. METHODS AND RESULTS: Lymphatic and blood vascular endothelial cells from mouse intestine were isolated using fluorescence-activated cell sorting, and transcriptional profiling was performed. We found that the axonal guidance molecules Sema3A and Sema3D were highly expressed by lymphatic vessels. Importantly, we found that the semaphorin receptor Nrp-1 is expressed on the perivascular cells of the collecting lymphatic vessels. Treatment of mice in utero (E12.5-E16.5) with an antibody that blocks Sema3A binding to Nrp-1 but not with an antibody that blocks VEGF-A binding to Nrp-1 resulted in a complex phenotype of impaired lymphatic vessel function, enhanced perivascular cell coverage, and abnormal lymphatic vessel and valve morphology. CONCLUSIONS: Together, these results reveal an unanticipated role of Sema3A-Nrp-1 signaling in the maturation of the lymphatic vascular network likely via regulating the perivascular cell coverage of the vessels thus affecting lymphatic vessel function and lymphatic valve development.

Aider les étudiants en médecine à approcher la mort [Helping medical students to approach death].

A project recently launched by the Faculty of biology and medicine of Lausanne introduces the approach of facing death during both the dissection and the course of clinical activities. Existential questions relating to mortality are bound to arise sooner or later during the course of the study. For the sake of humanized clinical practice, these questions must be confronted. In response to a request by a student association, an accompanying curriculum with active student's contribution through encounters with death in anatomy and clinical situations was created in Lausanne. Students will benefit from this new program throughout their curriculum. This program is the first of its kind in Switzerland.

Productive HIV-1 infection of primary CD4+ T cells induces mitochondrial membrane permeabilization leading to a caspase-independent cell death.

We have explored in vitro the mechanism by which human immunodeficiency virus, type 1 (HIV-1) induces cell death of primary CD4+ T cells in conditions of productive infection. Although HIV-1 infection primed phytohemagglutinin-activated CD4+ T cells for death induced by anti-CD95 antibody, T cell death was not prevented by a CD95-Fc decoy receptor, nor by decoy receptors of other members of the TNFR family (TNFR1/R2, TRAILR1/R2/OPG, TRAMP) or by various blocking antibodies, suggesting that triggering of death receptors by their cognate ligands is not involved in HIV-induced CD4 T cell death. HIV-1 induced CD4 T cell shrinkage, cell surface exposure of phosphatidylserine, loss of mitochondrial membrane potential (Deltapsim), and mitochondrial release of cytochrome c and apoptosis-inducing factor. A typical apoptotic phenotype (nuclear chromatin condensation and fragmentation) only occurred in around half of the dying cells. Treatment with benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, a broad spectrum caspase inhibitor, prevented nuclear chromatin condensation and fragmentation in HIV-infected CD4+ T cells and in a cell-free system (in which nuclei were incubated with cytoplasmic extracts from the HIV-infected CD4+ T cells). Nevertheless, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone did not prevent mitochondrial membrane potential loss and cell death, suggesting that caspases are dispensable for HIV-mediated cell death. Our findings suggest a major role of the mitochondria in the process of CD4 T cell death induced by HIV, in which targeting of Bax to the mitochondria may be involved.

Targeting essential pathways in trypanosomatids gives insights into protozoan mechanisms of cell death.

Apoptosis is a normal component of the development and health of multicellular organisms. However, apoptosis is now considered a prerogative of unicellular organisms, including the trypanosomatids of the genera Trypanosoma spp. and Leishmania spp., causative agents of some of the most important neglected human diseases. Trypanosomatids show typical hallmarks of apoptosis, although they lack some of the key molecules contributing to this process in metazoans, like caspase genes, Bcl-2 family genes and the TNF-related family of receptors. Despite the lack of these molecules, trypanosomatids appear to have the basic machinery to commit suicide. The components of the apoptotic execution machinery of these parasites are slowly coming into light, by targeting essential processes and pathways with different apoptogenic agents and inhibitors. This review will be confined to the events known to drive trypanosomatid parasites to apoptosis.

Prevalence of and risk factors for biliary carriage of bacteria showing worrisome and unexpected resistance traits.

Data on biliary carriage of bacteria and, specifically, of bacteria with worrisome and unexpected resistance traits (URB) are lacking. A prospective study (April 2010 to December 2011) was performed that included all patients admitted for <48 h for elective laparoscopic cholecystectomy in a Spanish hospital. Bile samples were cultured and epidemiological/clinical data recorded. Logistic regression models (stepwise) were performed using bactobilia or bactobilia by URB as dependent variables. Models (P < 0.001) showing the highest R(2) values were considered. A total of 198 patients (40.4% males; age, 55.3 ± 17.3 years) were included. Bactobilia was found in 44 of them (22.2%). The presence of bactobilia was associated (R(2) Cox, 0.30) with previous biliary endoscopic retrograde cholangiopancreatography (ERCP) (odds ratio [OR], 8.95; 95% confidence interval [CI], 2.96 to 27.06; P < 0.001), previous admission (OR, 2.82; 95% CI, 1.10 to 7.24; P = 0.031), and age (OR, 1.09 per year; 95% CI, 1.05 to 1.12; P < 0.001). Ten out of the 44 (22.7%) patients with bactobilia carried URB: 1 Escherichia coli isolate (CTX-M), 1 Klebsiella pneumoniae isolate (OXA-48), 3 high-level gentamicin-resistant enterococci, 1 vancomycin-resistant Enterococcus isolate, 3 Enterobacter cloacae strains, and 1 imipenem-resistant Pseudomonas aeruginosa strain. Bactobilia by URB (versus those by non-URB) was only associated (R(2) Cox, 0.19) with previous ERCP (OR, 11.11; 95% CI, 1.98 to 62.47; P = 0.006). For analyses of patients with bactobilia by URB versus the remaining patients, previous ERCP (OR, 35.284; 95% CI, 5.320 to 234.016; P < 0.001), previous intake of antibiotics (OR, 7.200; 95% CI, 0.962 to 53.906; P = 0.050), and age (OR, 1.113 per year of age; 95% CI, 1.028 to 1.206; P = 0.009) were associated with bactobilia by URB (R(2) Cox, 0.19; P < 0.001). Previous antibiotic exposure (in addition to age and previous ERCP) was a risk driver for bactobilia by URB. This may have implications in prophylactic/therapeutic measures.

Permanent pacemaker implantation after transcatheter aortic valve implantation: impact on late clinical outcomes and left ventricular function.

BACKGROUND Very few data exist on the clinical impact of permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation. The objective of this study was to assess the impact of PPI after transcatheter aortic valve implantation on late outcomes in a large cohort of patients. METHODS AND RESULTS A total of 1556 consecutive patients without prior PPI undergoing transcatheter aortic valve implantation were included. Of them, 239 patients (15.4%) required a PPI within the first 30 days after transcatheter aortic valve implantation. At a mean follow-up of 22±17 months, no association was observed between the need for 30-day PPI and all-cause mortality (hazard ratio, 0.98; 95% confidence interval, 0.74-1.30; P=0.871), cardiovascular mortality (hazard ratio, 0.81; 95% confidence interval, 0.56-1.17; P=0.270), and all-cause mortality or rehospitalization for heart failure (hazard ratio, 1.00; 95% confidence interval, 0.77-1.30; P=0.980). A lower rate of unexpected (sudden or unknown) death was observed in patients with PPI (hazard ratio, 0.31; 95% confidence interval, 0.11-0.85; P=0.023). Patients with new PPI showed a poorer evolution of left ventricular ejection fraction over time (P=0.017), and new PPI was an independent predictor of left ventricular ejection fraction decrease at the 6- to 12-month follow-up (estimated coefficient, -2.26; 95% confidence interval, -4.07 to -0.44; P=0.013; R(2)=0.121). CONCLUSIONS The need for PPI was a frequent complication of transcatheter aortic valve implantation, but it was not associated with any increase in overall or cardiovascular death or rehospitalization for heart failure after a mean follow-up of ≈2 years. Indeed, 30-day PPI was a protective factor for the occurrence of unexpected (sudden or unknown) death. However, new PPI did have a negative effect on left ventricular function over time.

Qualité des statistiques de causes de décès: problèmes actuels et perspectives. [Quality of statistics on causes of death: current problems and perspectives].

Statistics of causes of death remain an important source of epidemiological data for the evaluation of various medical and health problems. The improvement of analytical techniques and, above all, the transformation of demographic and morbid structures of populations have prompted researchers in the field to give more importance to the quality of death certificates. After describing the data collection system presently used in Switzerland, the paper discusses various indirect estimations of the quality of Swiss data and reviews the corresponding international literature.

L'autopsie moléculaire de la mort subite cardiaque: de la salle d'autopsie au cabinet du praticien [Molecular autopsy of sudden cardiac death: from postmortem to clinical approach]

Sudden cardiac death is one of the most prevalent cause of death in developed countries. Its aetiology varies according to the age. Some cardiac diseases may explain sudden death with minimal or no anatomic findings. However, many cardiac diseases, as for example channelopathies and hypertrophic cardiomyopathy have a genetic basis. Therefore genetic analyses (molecular autopsy) are becoming a useful tool in forensic medicine to identify the cause of sudden cardiac death and to improve the early diagnosis of asymptomatic carriers among relatives.

Resuscitated sudden cardiac death caused by left main coronary artery compression by an aneurysm of the sinus of Valsalva.

A 49-year-old woman, without known cardiovascular risk factors. Hoarseness of voice caused by a paralysis of left vocal cord. She was admitted to hospital because of acute coronary syndrome, associated to resuscitated cardiac arrest (asystolia documented) without later neurology sequels. Physical examination was anodyne. Echocardiographic study demonstrated a compatible image with a large left sinus of Valsalva aneurysm (SVA) (Panel A) and mild aortic regurgitation. Cardiac catheterization confirmed the presence of left SVA (Panel B) that produced extrinsic compression of the left main coronary artery (Panels C and D). Repair surgery was made by means of closing the aneurysmal orifice with a patch of dacron. Intra-operatory echocardiographic control study found severe aortic regurgitation, so valvular replacement with 19 mm mechanical prosthesis and extension of the valve annulus with patch of dacron was performed, associated with bypass with safena vein graft to left coronary artery. SVA is a very infrequent cardiac anomaly, generally with silent clinical course until it ruptures. Myocardial ischaemia caused by coronary artery compression is unusual. We described the case of a patient diagnosed of left SVA, whose initial clinical manifestation was the appearance of resuscitated sudden cardiac death in the context of an acute coronary syndrome.