Chronic portal hypertension in the rat by triple-portal stenosing ligation.

A surgical technique based on the development of a triple stenosing ligation is used to worsen the complications inherent to the prehepatic chronic portal hypertension. The results have been compared with those obtained in rats with a single-portal stenosing ligation. An increase (p <.05) in the body, liver, spleen, and kidney weights as well as a decrease (p <.001) in the testes weight to body weight ratio were produced in both groups of animals. In addition, the variability in the obtained weights, particularly in the liver weight, stands out. The incidence of portosystemic and portohepatic collateral circulation and of the mesenteric venous vasculopathy increases in the animals with triple-portal stenosing ligation. The new proposed technique is a valid alternative to the classic one that used single portal stenosing ligation.     

Complete sub-His AV block caused by carotid sinus massage. Possible direct vagal effect on the His-Purkinje system

A 64 year old male patient, with frequent syncopes, underwent an electro-physiologic study. A complete left bundle branch block and a first degree His-Purkinje system atrioventricular block (AH = 100 msec, HV = 60 msec) were present in basal condition. Left carotid sinus massage caused extreme sinus bradycardia (with PP intervals as long as 3000 msec), without AH and HV interval changes. Right carotid sinus massage caused a His-Purkinje atrioventricular block. Ventricular asystole of 4800 msec occurred while the sinus cycle varied between 1440 and 590 msec. Since His-Purkinje atrioventricular block is induced by the right carotid sinus massage with PP intervals even shorter than the basal cycles and since the block was not reproduced at PP intervals longer than 1440 msecs, a direct vagal effect on the His-Purkinje system may be suggested, rather than a bradycardia dependent phase 4 block.     

A pilot study on the urinary excretion of porphyrins in human populations chronically exposed to arsenic in Mexico.

1 The aim of this pilot study was to investigate if the porphyrinuria produced by arsenic in rodents was present in humans chronically exposed to arsenic via drinking water. 2 The concentrations of uroporphyrin, coproporphyrin and total arsenic in urine were compared between 21 individuals exposed to arsenic in their drinking water (0.390 mg l-1) and 19 controls exposed to 0.012 mg l-1. 3 Arsenic-exposed individuals had significantly higher total arsenic concentrations in their urine than the control group. No increase in urinary porphyrin excretion was found in exposed individuals. However, an inversion of the coproporphyrin/uroporphyrin (COPRO/URO) ratio was observed in most exposed individuals. This inversion was caused both, by a decrease in coproporphyrin excretion and an increase in uroporphyrin excretion. 4 No demonstrable correlations between porphyrin excretion, the COPRO/URO ratio and total arsenic concentration in urine were found in exposed individuals.     

Early local complications following colostomy closure in cancer patients

Early surgical complications following colostomy closure in 65 cancer patients operated on at the Istituto Nazionale Tumori of Milan were evaluated retrospectively. The overall complication rate was 24.6 per cent, including infections (13.8 per cent), fistulas (6.1 per cent), wound dehiscence (3.0 per cent), and distal stenosis (1.5 per cent). Type and rate of complications were analyzed to find a correlation with type, site, and location of colostomy, technique of closure, presence or absence of drains, or time interval between construction and closure of colostomy. No statistically significant association between the aforementioned factors and occurrence and rate of complications was found. The authors think, therefore, that surgical attention, including meticulous manipulation of the stoma, avoidance of contamination of the wound, tension of sutures, dead spaces, and collection of blood in the wound, and use of antibiotics and antiseptics are the most important principles to minimize postoperative complications.     

Human retinal pigment epithelial cells cultured in hyperglycemic media accumulate increased amounts of glycosaminoglycan precursors.

Confluent human retinal pigmented epithelial cells were cultured on microcarrier beads in the presence of 5.6 or 26 mmol/l glucose with or without the aldose-reductase inhibitor Sorbinil (200 microM) for 2 wk. At the end of the incubation period, perchloric acid extracts were prepared and analyzed by 31P nuclear magnetic resonance spectroscopy. As assessed by this method, the phosphorylated metabolites of cells incubated with 5.6 or 26 mmol/l glucose differed significantly in the concentrations of a number of uridine diphosphate (UDP)-conjugated monosaccharides, which were elevated two- to threefold in cells incubated in 26 mmol/l glucose over control samples. The affected metabolites were identified (through a series of spiking experiments) to be UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine, and UDP-glucuronic acid. Coincubation of the cells with Sorbinil 200 microM in the presence of 26 mmol/l glucose had no effect on this accumulation. Under normal circumstances, these molecules selectively and sequentially are incorporated into the polysaccharide chains of glycosaminoglycans (GAGs), whose presence and distribution in the basement membranes is affected adversely by diabetes mellitus. These data suggest that the availability of the monosaccharide precursor is not the rate-limiting step for GAG synthesis in the presence of pathologic glucose concentrations. Thus, the lost GAG content in the basement membranes of diabetic patients may be caused by changes elsewhere in the biosynthesis and/or catabolism of the polysaccharide-linked protein molecules.