Studies on the mechanism of alloxan-diabetes potentiation of carbon tetrachloride-induced liver necrosis

Carbon tetrachloride (CCl4)-induced liver necrosis in alloxan diabetic rats is markedly more intense than in controls as established by determination of isocitric dehydrogenase activity in plasma or by histological techniques. The covalent binding (CB) of CCl4 reactive metabolites to liver microsomal lipids is higher in alloxan diabetic rats than in controls. Cytochrome c reductase activity remains unchanged in alloxan diabetic rats. All the alterations described above observed in the diabetic animals are reverted by insulin administration. CCl4-induced lipid peroxidation of microsomal lipids, in contrast, is equally intense in controls than in alloxan diabetic animals and it is not modified by insulin treatment. Body temperature in alloxan diabetic animals treated with CCl4 is lower than in controls treated with the hepatotoxin. Results suggest that part of the enhanced necrogenic response of the liver observed in alloxan diabetic rats is due to increased CB to liver cell constituents but available evidence from the present and another work suggest that increased susceptibility of the liver from alloxan diabetic animals play a major role in the potentiation of CCl4 deleterious effects.

Covalent binding of carbon tetrachloride metabolites to the heme moiety of cytochrome P-450 and its degradation products

Trichloromethyl free radicals (. CCI) produced during a benzoyl peroxide decomposition of CCl4 covalently bind to hemin. Enzymatically produced . CCl3 by an NADPH anaerobic liver microsomal activation of CCl4, covalently binds to heme and heme degradation products from CO-binding particles. 14C from CCl4 covalently binds to heme and heme degradation products from liver CL-binding particles from rats treated with 14CCl4. In vivo covalent binding of 14CCl4 reactive metabolites to proteins from CO-binding particles is higher than that to the whole microsomal proteins. The possible correlation between binding of . CCl3 to heme and protein moieties of P-450 and CCl4 induced P-450 destruction is discussed.

Liver microsomal drug-metabolizing enzyme activity: enhancement by blockade of degradative processes in promethazine-treated rats

Daily injection of promethazine over 4 days significantly increased the liver cytochrome P-450 content and ethyl morphine N-demethylase activity. These increases were evident after the first dose and were prevented by puromycin or actinomycin D administration. Repeated administration of promethazine does not increase the liver's ability to incorporate [14]C DL-leucine in microsomes but slows down the decay of radioactivity in microsomes previously labelled with ([14C]-guanidino) arginine. Repeated treatment with promethazine leads to a marked proliferation of the rough endoplasmic reticulum (RER) and a slight increase in the smooth endoplasmic reticulum (SER). Our findings suggest that the enhancement of P-450 and EM-ase activity result from the decelerating effect of promethazine on protein degradation.

[Chronodynocardiometry in healthy children. 1: Systolic times]

At the National Institute of Pediatry (IMAN) were studied the phonomechanocardiographic recorders obtained of 125 children, all were eutrophic and healthy. The measure of the systolic time intervals were the purpose of the study. Children's age varied from 2 months old to 18 years old; 82 boys and 43 girls. The duration of the R-R space increased according to age (P less than 0.001), the electroacoustic systole and the ejection time showed more duration in older children (r = 0.61 and 0.77 respectively). In opposite, the pre-ejection time as well as its phases, had a similar duration in all ages. Tables of values and ranges of the systolic time intervals according to age are presented. The systolic time intervals were correlated to the R-R space duration, and showed a direct proportion with the electroacoustic systole (r = 0.76) and ejection time (r = 0.83), but the pre-ejection time had not significant changes. The electroacoustic diastole duration was proportional to the R-R space (r = 0.96). The regression equations were calculated to evaluate the normal range of the systolic time intervals in children, obviously in accordance to cardiac frequency.

Effects of repeated administration of rat 2-diethylaminoethyl-2-2-diphenylvalerate-HCI (SKF 525 A) on liver

Repetitive administration to male rats of 2-diethylaminoethyl-2-2-diphenyl-valerate-HCI (SKF 525 A) (50 mg/kg, i.p.), decreases the intensity of [14C]-orotic acid incorporation/mg of RNA but not the 14C-incorporation/g liver. The RNA content/g liver is significantly higher in SKF-treated animals than in controls. Decay of label in liver RNA from [14C] orotic acid pretreated animals, is not significantly different in SKF 525 A treated animals than in controls. SKF 525 A repetitive administration, does not modify the rate of incorporation of 32P in liver microsomal lipid when results are expressed per microgram of inorganic phosphorus but it does when expressed in terms of per gram liver. There is a significant decrease in the decay rate of label from 32P-prelabeled liver microsomal phospholipids when animals are treated with SKF 525 A. There is a significant increase in the protein and phospholipid content in the smooth endoplasmic reticulum fraction. The electron microscopy of liver from SKF 525 A-treated animals, shows the presence of large areas of round vesicles of swollen endoplasmic reticulum, partly due to smooth component and part due to rough component, having detached the ribosomes from their membranes. Results suggest an inhibitory effect of SKF 525 A on RNA and phospholipid degradative processes.

[Early mechanical respiration with prolonged inspiration in the treatment of acute respiratory insufficiency in the newborn]

The experience at the Servicio de Medicina Perinatal Pediátrica of the Centro Hospitalario "20 de Noviembre" of the ISSSTE is reported on the application of a ventilatory assistance criterion to treat the severe respiratory distress syndrome in the newborn. Early application of intermittent mechanical ventilation (IMV) is established to avoid clinical impairment. The mechanical ventilator is used in such a way that without withdrawing therapeutic effectiveness, it may cut down to a minimum complications derived from the use of IMV. The results show increase in survivorship, specially among the lower weight population and less complications than with the previous management method, in spite of a 70% increase in the use of IMV.

[Visual somatosensory and auditory evoked potentials in multiple sclerosis]

In a group of 15 patients with multiple sclerosis and in a control group of 20 healthy subjects visual evoked potentials produced with flashes or checkerboard pattern, auditory evoked potentials after stimulation with three different tones, and somatosensory evoked potentials after stimulation of the left, right or both median nerves, and reactions to stroboscopic stimulation at seven different frequencies were investigated. Recording was done with unipolar leads from frontal, central, occipital and temporal regions on the left and right side. In patients with multiple sclerosis the cortical responses to all these stimuli had lower amplitude than in healthy subjects, and the reponses to stroboscopic stimulation were also abnormal in the group of patients. Different clinical signs related to various defects of sensory functions showed a high correlation with electrophysiological anomalies. Non-linear discrimination analysis was carried out using 13 variants (the amplitudes were calculated from peak to peak and correlation coefficients were calculated between identical regions on the left and right side) comparing the group of patients with the control group. Using this method it was possible to establish the correct diagnosis in all cases of multiple sclerosis and 85% of healthy subjects could have been included into the asymptomatic group. Since the methods used in these investigations are easy and can be easily automated the authors think that they could be very useful in the clinical diagnosis of multiple sclerosis.

Visual, auditory and somatosensory evoked responses in patients with cerebrovascular disorders

A diagnostic evoked response battery, consisting of visual evoked responses to flashes and to a checkerboard pattern, auditory evoked responses to three different tones and somatosensory evoked responses to left, right and bilateral median nerve stimulation, was administered to 20 patients with strokes, and compared with 20 normal control subjects. Recordings were obtained at C3, C4, O1, O2, T3 and T4. Evoked responses were found to be of lower amplitudes and lower amplitudes and lower waveform symmetry (expressed by low correlation coefficients between left and right homologous areas) in the patients than in normal subjects. A discriminant equation with 17 variates was computed to separate the two groups. One patient (5%) and 2 (10%) normal subjects were misclassified. Comparison between patients with left or right lesions showed that somatosensory and auditory evoked responses were very useful for identification of the affected side. Quantitative study of evoked responses to different types of stimuli and sensory modalities provides a sensitive method for the evaluation of brain function in such patients. This technique gives higher accuracy than the routine EEG examination in terms of both the percentage of dectection and the accuracy of localization of the affected side.