PGE1 abolishes the mitochondrial-independent cell death pathway induced by D-galactosamine in primary culture of rat hepatocytes

Background and Aim:  PGE₁ reduces in vivo and in vitro D-galactosamine (D-GalN)-induced cell death in hepatocytes. The present study was undertaken to elucidate the intracellular pathway by which D-GalN induces cell death in cultured hepatocytes. In addition, we evaluated if PGE₁ was able to modulate different parameters related to D-GalN-induced apoptosis in cultured rat hepatocytes.
Methods:  Hepatocytes were isolated from male Wistar rats (225–275 g) by the classical collagenase procedure. PGE₁ (1 µM) was administered 2 h before D-GalN (5 mM) in primary culture of rat hepatocytes. Apoptosis was determined by DNA fragmentation and caspase-3, -6, -8 and -9 activation in hepatocytes. Caspase activation was evaluated by the detection of the related cleaved product and its associated activity. Cell necrosis was determined by the measurement of lactate dehydrogenase (LDH) activity in culture medium. To elucidate the role of mitochondria, we measured neutral (nSMase) and acid (aSMase) sphingomyelinase, as well as the expression of cytochrome c in mitochondria and cytoplasm fractions from D-GalN treated hepatocytes.
Results:  D-GalN induced caspase-3 activation and DNA fragmentation in hepatocytes. This apoptotic response was not associated with the activation of caspase-6, -8 or -9. The use of specific inhibitors confirmed that only caspase-3 was involved in D-GalN-induced apoptosis. D-GalN did not modify nSMase and aSMase activities, nor mitochondrial cytochrome c release in hepatocytes.
Conclusions:  D-GalN induced apoptosis through caspase-3 activation but without modification of the activity of caspase-6, -8, -9, SMases or cytochrome c release. PGE₁ appears to prevent D-GalN-induced apoptosis by a mitochondria-independent mechanism.     

Application of the fractionator and vertical slices to estimate total capillary length in skeletal muscle

A new stereological method is proposed which combines vertical slice projections with the fractionator to estimate the total capillary length in a skeletal muscle. The method was demonstrated on the soleus muscle of a Wistar rat. The implementation required capillary highlighting, tissue sampling, and data acquisition in the form of intersection counts between capillary projections and cycloid test lines. The capillaries were demonstrated using vascular perfusion (with gelatine) of the hind leg of the rat. The sampling procedure followed the fractionator design, namely a multistage systematic sampling design with a known sampling fraction at each stage. To make the design unbiased, vertical slices were used; for efficiency, the vertical axis was chosen parallel to the main axis of the muscle. As prescribed to avoid bias, the cycloid test lines were superimposed on the slice projections, viewed under the light microscope, with their minor axes normal to the vertical axis. The estimation precision was compared for different sampling and subsampling fractions. The proposed method was globally highly efficient, unbiased, and easy to implement.     

Baroreflex Sensitivity: Methods, Mechanisms, and Prognostic Value

A large bulk of data collected over the last 25 years links reflex autonomic activation during acute myocardial ischemia with risk of developing lethal arrhythmias. Specifically, evidence obtained in an experiniental preparation in chronically infarcted dogs supported the concept that sympathetic hyperactivity enhances likelihood for ventricular tachyarrhythmias, vagal activation exerts protective effects. Based on this knowledge, it was first proposed by our group that analysis of aufonomic control of heart rate could provide information relevant to risk stratification in post-myocardial infarction individuals. Among several possibilities, baroreflex sensitivity ivas evaluated by correlating blood pressure rise induced by bolus injections of phenylephrine with the consequent beat to beat R-R interval lengthening. Experimental studies involving direct recordings from single neural vagal fibers directed to the heart documented that baroreflex sensitivity closely reproduces cardiac vagal activity. In a large group of conscious dogs it was shown that a depressed baroreflex sensitivity was highly predictive of the risk for ventricular fibrillation during acute myocardial ischemia. The clinical prognostic value of baroreflex sensitivity has already been confirmed in pilot studies conducted by different groups of investigators. Overall, the phenylephrine test has been performed in several hundred patients with no reports of side effects. An ongoing multicenter study, the ATRAMI (Autonomic Tone and Reflexes After Myocardial Infarction) is aimed to definitively assess the predictive value of baroreflex sensitivity and heart rate variability in patients with a prior myocardial infarction, While the enrollment is still ongoing, this study has already provided an important methodological information about the possibility of using non invasive technique to record blood pressure by means of FINAPRES, to evaluate baroreflex sensitivity. Comparison among 142 tests performed with simultaneous recording from an intraarterial line and from FINAPRES indicated a strong correlation (r = 0.9) between the two methods. ATRAMI is expected to close the enrollment in the near future. To date, baroreflex sensitivity appears to be a safe and non-invasive test likely to provide meaningful information on autonomic balance and consequently on risk profile of patients with a prior myocardial infarction.     

Lung cancer in a health area of Spain: incidence,characteristics and survival

GARCÍA PRIM J.M., GONZÁLEZ BARCALA F.J., PAZ ESQUEJE J., POSE REINO A., FONDEVILA LÓPEZ A. & VALDÉS CUADRADO L. (2010) European Journal of Cancer Care 19 , 227–233
Lung cancer in a health area of Spain: incidence, characteristics and survival To examine the incidence, characteristics, therapeutic approach and survival of diagnosed lung cancer (LC) in the Santiago de Compostela Health Area. A retrospective study was carried out on LC for a period of 3 years. Of the 481 cases collected, 92.7% were male. The median age was 66.93 years. The crude incidence for men and women was 80.71 and 5.84 per 100 000 inhabitants respectively. Among the non‐small cell lung cancers (NSCLC), 68.1% were diagnosed in stage IIIB or IV. The cancer had already spread in 62.2% of the small cell lung cancer (SCLC). Chemotherapy was used in 51.6% of patients. The survival probability from the first to the fifth year was 47.7%, 24.3%, 12.9%, 10% and 8.9% respectively. The median survival at 5 years was 12.12 months for NSCLC, rising to 29.8 months in stage I, and 8.85 months in SCLC. In our Health Area LC occurs more often in men, in whom the prevalence of smoking is very high. The most common histology type was squamous cell carcinoma. In the majority of cases, the diagnosis is made in the advanced stages, which accounts for the low percentage of surgical treatments and the short survival.     

Wide QRS Complex Arrhythmia with Alternating QRS Morphology: What Is the Mechanism?

A 75‐year‐old man was admitted due to an electrical storm with appropriate recurrent implantable cardioverter defibrillator (ICD) discharges. The patient had had an extensive anterolateral myocardial infarction with associated severe left ventricular dysfunction 10 years earlier (left ventricular ejection fraction, 25%), and an ICD was placed 9 years before admission for primary prevention of sudden cardiac death. A first invasive study induced up to five ventricular tachycardias and an extensive endocardial substrate ablation was performed. Despite intravenous β‐blockers, general anesthesia and procainamide infusion, the patient continued to have recurrent episodes of very slow sustained ventricular tachycardia with a right bundle branch block pattern. In a subsequent invasive study, no mid‐diastolic activity was found despite careful mapping during the induced clinical ventricular tachycardia and ablation attempts inside the apical endocardial scar were unsuccessful. A percutaneous epicardial approach with navigation system support (EnSite Precision^TM Cardiac Mapping System v. 2.0, St. Jude Medical, St. Paul, MN, USA) without antiarrhythmic infusion was planned. A wide QRS complex rhythm with alternating QRS morphology was readily induced by epicardial ventricular pacing trains (Fig. 1, top) that elicited both arrhythmia QRS patterns with very long stimulus QRS intervals (Fig. 1, bottom). What is the possible mechanism of this arrhythmia? Do we need further pacing maneuvers during the arrhythmia to localize critical sites at which ablation pulses can predictably be successful?