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.     

p53 OVEREXPRESSION AND HUMAN PAPILLOMAVIRUS INFECTION IN TRANSITIONAL CELL CARCINOMA OF THE URINARY BLADDER: CORRELATION WITH HISTOLOGICAL PARAMETERS

Seventy-nine transitional cell carcinomas (TCCs) of the urinary bladder (25 grade 1, 22 grade 2, and 32 grade 3 tumours) were examined for p53 overexpression by immunohistochemistry with a monoclonal antibody and for human papillomavirus (HPV) infection by the polymerase chain reaction (PCR). Positive immunostaining for p53 was detected in 40·5 per cent of the cases; the percentage of positive cases was significantly lower in low-grade (G1 and G2) TCCs than in high-grade (G3) tumours (10·6 per cent vs. 84·4 per cent; P <0·0001). The overall rate of HPV infection was 32·9 per cent; 20·3 per cent of the cases were positive for HPV 16, 3·8 per cent for HPV 18, and 8·9 per cent for both. Consensus primers as well as type-specific primers for HPV types 6, 11, and 33 failed to detect any additional case with HPV infection. The prevalence of HPV 16 and/or HPV 18 infection was significantly higher in low-grade than in high-grade tumours (44·7 per cent vs. 15·6 per cent; P =0·0061). p53-positive cases were more common among papillary, deeply infiltrating tumours, and HPV-positive cases among papillary, non-infiltrating lesions. According to these data, p53 overexpression and HPV 16/18 infection are common findings in bladder TCC and there appears to be an inverse correlation of p53 overexpression and of HPV infection with tumour aggressiveness. The possibility of different molecular pathways in superficial low-grade and in invasive high-grade tumours is suggested.     

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.     

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.     

NUTRITIONAL STATUS IN CHRONICALLY ALCOHOLIC MEN FROM THE MIDDLE SOCIOECONOMIC CLASS AND ITS RELATION TO ETHANOL INTAKE

Two-hundred and fifty chronically alcoholic men (mean age, 41± 11 years) entering an alcoholism treatment programwere studied. Detailed clinical history, nutritional assessmentand measurement of muscle strength by electronic myometer wereperformed in each case. In addition, hepatic ultrasonographyand liver biopsy, echocardiography and radionuclide cardiacscanning, and electrophysiological testing of peripheral nerveswere performed when there was clinical evidence of liver disease,cardiomyopathy or neuropathy, respectively. Alcoholic cirrhosiswas diagnosed in 20 cases, skeletal myopathy in 117, dilatedcardiomyopathy in 20 and peripheral neuropathy in 41 cases.No patients with chronic myopathy or cardiomyopathy showed eitherclinical or laboratory evidence of malnutrition. Patients withcirrhosis showed a significantly lower lean body mass than controls(P = 0.03) and significantly lower nutritional protein levelsthan those alcoholics without cirrhosis. Alcoholics with peripheralneuropathy had significantly lower anthropometric parametersand nutrition protein levels than their counter parts (P <0.001). However, in the multivariate analysis, the only independentfactor for developing these complications of alcoholism wasthe total lifetime dose of ethanol (P < 0.001). We concludethat alcohol-related diseases are common in asymptomatic alcoholicmen and these diseases appear to be due to an accumulative toxiceffect of ethanol. Age and nutritional status do not seem toplay a part in the development of such diseases