Metallothionein and its relationship to the metabolism of dietary zinc in rats

Metallothionein (MTN), a low molecular weight cytoplasmic metalloprotein has previously been implicated in the metabolism of Zn. Experiments were conducted with rats to determine the effect of feeding varying levels of dietary Zn for short periods on the increase or decrease in MTN-bound Zn. The results indicated that MTN-Zn in both liver and intestinal mucosal cytosol responded rapidly to an altered dietary Zn level and that serum Zn was directly related to the appearance of MTN. 65Zn absorption also responded rapidly to a change in dietary Zn and was inversely correlated with intestinal mucosal MTN-Zn. Hepatic 65Zn uptake appeared to be directly correlated with liver MTN-Zn. A 24 hour fast increased MTN-Zn in rats fed two different levels of Zn except in those rats that were previously treated with actinomycin D. The antibiotic, which blocks DNA-dependent RNA synthesis, appeared to block Zn uptake from blood to the liver. These findings offer support for the involvement of MTN in zinc metabolism.     

Defining the precapillary sphincter

Influence of denervation on phospholipid metabolism in the vas deferens and effect of phospholipase C treatment on sensitivity of the vas deferens for noradrenaline were studied. The incorporation of 32P-orthophosphate into phosphatidylethanolamine and phosphatidylcholine was markedly increased by denervation. Incorporation of 32P-orthophosphate into proteolipid was accelerated more than that of 3H-leucine. Sensitivity of the denervated vas deferens for noradrenaline was strongly reduced by phospholipase C treatment. These data suggest that the supersensitivity of the denervated vas deferens for noradrenaline was mainly due to the increase in phospholipids.     

Ethanol-mediated neutrophil extravasation in feline pancreas

Ethanol is a common cause of both acute and chronic pancreatitis. Studies in other organs suggest that polymorphonuclear neutrophils activated by ethanol may cause tissue injury in a variety of conditions. The aim of this study was to investigate the effects of ethanol on neutrophil extravasation in the feline pancreas. Pancreata were isolated and perfused at different flow rates with varying concentrations of ethanol in either a physiological or neutrophil depleted perfusate. Neutrophil extravasation was assessed by measuring pancreatic tissue myeloperoxidase (MPO) activity. Ethanol at 2.5% (54.25 mmol/liter) was the lowest concentration that still caused significant neutrophil extravasation (3.1+/-0.8 vs 1.9+/-0.2 units, P<0.05) and was accompanied by an increase in vascular resistance of 15%. Reduction of pancreatic perfusion by 15% did not significantly increase neutrophil extravasation. (1.1+/-0.3 vs 1.6+/-0.2 units, NS) Perfusion of the pancreas with neutrophil-depleted blood containing either ethanol or saline, followed by perfusion with an ethanol-free perfusate, showed an increase in neutrophil extravasation in the ethanol group compared to the control group (3.2+/-0.9 vs 1.9+/-0.2 units, P<0.05). In conclusion, ethanol causes neutrophil extravasation in the feline pancreas independent of blood flow changes and occurs despite the absence of direct neutrophil exposure to ethanol.     

A sonographically guided technique for central venous access

OBJECTIVE: The internal jugular vein (IJV) is an important access to the central venous system. We compared sonographically guided technique with the traditional anatomic landmark technique for IJV catheterization. SUBJECTS AND METHODS: In a prospective randomized trial, 100 patients underwent routine catheterization of the IJV (50 patients in the sonography group and 50 patients in the anatomic landmark group). Access time, failure rates, and complication rates were evaluated. In addition, the physicians' number of years of experience with catheter insertion was recorded. RESULTS: Access time was markedly shorter with the sonographically guided technique (mean, 15.2 sec; range, 8-76 sec) than with the anatomic landmark technique (mean, 51.4 sec; range, 3-820 sec) (p = .001). The failure rate was significantly lower with the sonographically guided technique (p = .002). Complications were fewer with the sonographically guided technique (neck hematoma, 2% versus 10%; plexus irritation, 4% versus 6%; carotid artery puncture, 0% versus 12%). We found that the number of years of postgraduate clinical training was greater in the group of physicians using the anatomic landmark technique. CONCLUSION: The sonographically guided technique is associated with less risk and less inconvenience for patients, especially critically ill patients, for whom the technique provides fast, safe, and easy IJV catheterization.     

Effect of a new exopolysaccharide on animal body

The influence of new exopolysaccharide, synthesized by Candida tropicalis and Pseudomonas sp. consortium in ethanol, on the animal body was studied in chronic experiments conducted in 200 non-inbred white rats. The animals were sacrificed after 3, 10 and 18 months of follow-up. The results of the investigations permit a conclusion that exopolysaccharide given to the animals during a long period does not produce a significant effect on the animal's growth and development, on the antitoxic function of the liver, on the parameters of protein, lipid and carbohydrate metabolism, on oxidizing phosphorylation in the mitochondria of the liver, and is low-hazard with respect to allergenic properties.     

Mutant PCNA alleles are associated with cdc phenotypes and sensitivity to DNA damage in fission yeast

Twenty-eight site-directed mutations were introduced into the fission yeast gene (pcn1+) that encodes proliferating cell nuclear antigen (PCNA) and their in vivo effects analyzed in a strain with a null pcn1 background. Mutants defective in enhancing processivity of DNA polymerase delta have previously been identified. In this study, we assessed all of the mutants for their sensitivities to temperature, hydroxyurea, UV irradiation and methyl methanesulfonate (MMS), and specific mutants were also tested for sensitivity to gamma irradiation. One cold-sensitive allele, pcn1-3, was characterized in detail. This mutant had a recessive cold-sensitive cdc phenotype and showed sensitivity to hydroxyurea, UV, and gamma irradiation. At the non-permissive temperature pcn1-3 protein was able to form homotrimers in solution and showed increased stimulation of both synthetic activity and processivity of DNA polymerase delta relative to the wild-type Pcn1+ protein. Epistasis analyses indicated that pcn1-3 is defective in the repair pathway involving rad2+ but not defective in the classical nucleotide excision repair pathway involving rad13+. Furthermore, pcn1-3 is either synthetically or conditionally lethal in null checkpoint rad backgrounds and displays a mitotic catastrophe phenotype in these backgrounds. A model for how pcn1-3 defects may affect DNA repair and replication is presented.