Low dose oral alpha-interferon therapy for patients seropositive for human immunodeficiency virus type-1 (HIV-1)

Thirty eight symptomatic and two asymptomatic patients seropositive for human immunodeficiency virus type-1 (HIV-1) were treated with a natural human interferon alpha (HuIFN alpha). Patients were given 2 IU/kg HuIFN alpha orally once daily in powdered maltose held in the mouth to promote mucosal absorption. This oral immunomodulating HuIFN alpha therapy resulted in an increase in CD4+ lymphocytes, an increase in weight, and a dramatic alleviation of clinical symptoms related to HIV-1 infection.     

Gastric exocrine “failure” in critically ill patients: incidence and associated features

Following the observation that many critically ill patients cannot maintain their gastric juice pH below 4 without treatment a study was performed to measure the gastric juice pH in such patients and relate it to other clinical data. The case notes of 64 patients who had been admitted to the intensive care unit and taken part in two trials of ranitidine treatment were reviewed. During those trials gastric juice was aspirated hourly and the pH and volume measured. In this study the values recorded during a six hour untreated control phase were used. Data on age, diagnosis, treatment, outcome, episodes of hypoxia, episodes of hypotension, and use of inotropic drugs were also reviewed. Full data were available for 61 patients: 27 had a mean baseline pH of >5 during the control phase and 34 a mean baseline pH of <5. Significantly more of those with a high pH suffered hypotension (21/27 v 13/34) and received inotropic drugs (16/27 v 8/34).These findings suggest that hypotension in critically ill patients adversely affects gastric exocrine function; prophylaxis with drugs that can improve gastric mucosal blood flow may be more effective than with antacids.     

DNA sequence changes in mutations induced by ultraviolet light in the gpt gene on the chromosome of Escherichia coli uvr+ and urvA cells

Summary Sequence changes in mutations induced by ultraviolet light are reported for the chromosomal Escherichia coli gpt gene in almost isogenic E. coli uvr ⁺ and excision-deficient uvrA cells. Differences between the mutagenic spectra are ascribed to preferential removal of photoproducts in the transcribed strand by excision repair in uvr ⁺ cells. This conclusion is confirmed by analysis of published results for genes in both uvr ⁺ and uvr ^– cells, showing a similar selective removal of mutagenic products from the transcribed strand of the E. coli lacI gene and of the lambda phage cl repressor gene. Comparison of these data with published results for ultraviolet mutagenesis of gpt on a chromosome in Chinese hamster ovary cells showed that a mutagenic hot spot in mammalian cells is not present in E. coli; the possibility is suggested that the hot spot might arise from localized lack of excision repair. Otherwise, mutagenesis in hamster cells appeared similar to that in E. coli uvr ⁺ cells, except there appears to be a smaller fraction of single-base additions and deletions (frameshifts) in mammalian than in bacterial cells. Phenotypes of 6-thioguanine-resistant E. coli showed there is a gene (or genes) other than gpt involved in the utilization of thioguanine by bacteria.     

X-ray diffraction studies of lipid phase transitions in cholesterol-rich membranes at sub-zero temperatures

In X-ray diffraction studies of hydrated (greater than 60%) cholesterol/dioleoylphosphatidylcholine mixtures the lipid packing band showed an abrupt transition from liquid crystal-type to gel-type position and definition at a temperature which decreased progressively to almost -50 degrees C as the proportion of cholesterol was increased to a saturation level of about 50 mol%. Plots of transition temperature against composition (mol% cholesterol) and of peak position against composition provided evidence of a significant change in phospholipid configuration at about 20 mol% cholesterol. However, the data overall suggested a uniform dispersion of the cholesterol molecules in the phospholipid bilayer at all concentrations up to the saturation point. Parallel studies of hydrated lipid extract of erythrocyte membranes and of several cholesterol-rich membrane preparations showed a similar overall change from liquid crystal-type packing at +20 degrees C to a gel-type packing at -30 degrees C to -40 degrees C but without displaying a defined transition temperature.     

Purification of thymidine-diphospho-D-glucose 4,6-dehydratase from an erythromycin-producing strain of Saccharopolyspora erythraea by high resolution liquid chromatography

TDP-D-glucose 4,6-dehydratase was purified from Saccharopolyspora erythraea, the producer of the macrolide antibiotic erythromycin A, by a high resolution chromatographic method that exploited the difference in the behavior of the protein on anionic exchange chromatography in Tris/HCl or phosphate buffers. By this method, the enzyme was purified approximately 900-fold by two anionic exchange steps to more than 90% homogeneity. It was further purified to apparent homogeneity by hydrophobic interaction chromatography. The enzyme is a homodimer of Mr 36,000 subunits, is highly specific for TDP-D-glucose, requires NAD+ as cofactor, and shows a K'm of 34 microM and V'max of 26 mumol h-1 mg-1 of protein for TDP-D-glucose. TDP and TTP strongly inhibit the enzyme at 2 mM. The maximal TDP-D-glucose 4,6-dehydratase activity coincides with the time of erythromycin production, suggesting that this enzyme is involved in antibiotic biosynthesis.     

Kidney transplantation in Canada, 1981-84.

The Canadian Renal Failure Register was established in 1980. Data have been collected annually for all Canadian patients in whom irreversible kidney failure developed and who required dialysis or transplantation. The authors present actuarial patient and graft survival rates for 1981-84. In 1984, patients with a functioning renal graft accounted for 43.9% of the patients with end-stage renal disease. The number of transplants performed increased from 482 in 1981 to 662 in 1984; however, 1,022 patients undergoing dialysis (25.2%) were on an active waiting list for a transplant at the end of 1984. Greater effort is needed to increase the transplantation rate.     

Micro Radiometric Method for Study of Acid-insoluble Materials in Monolayer Cell Cultures

A simple radiometric procedure for study of acid-insoluble products synthesized in monolayer cell cultures is described. Cell cultures were produced directly on the bottom surface of scintillation vials or on glass cover slips (8 X 30 mm). The cells were labeled and extracted; the radioactivity was determined while the cells remained affixed to the glass surface upon which they were grown. This procedure enabled rapid investigations of certain biosynthetic processes to be carried out by using many individual cell cultures. The method was applied to an investigation of (3)H-thymidine incorporation induced by vaccinia virus in a 5-bromodeoxyuridine-resistant cell line. (14)C-labeling was evaluated as an alternate procedure for cell quantitation.     

A physiological study ofTeucrium scorodonia ecotypes which differ in their susceptibility to lime-induced chlorosis and iron-deficiency chlorosis

Summary Edaphic ecotypes ofTeucrium scorodonia have been shown which differ in their susceptibility to lime-induced chlorosis. Plants especially resistant or susceptible to lime-induced chlorosis were found to be similarly resistant or susceptible to iron-deficiency chlorosis. Differences were found in the chlorophyll-iron and dry weight-chlorophyll relationships of the leaves of green and chloroticTeucrium plants, similar effects being produced by growth on a calcareous soil, in iron-deficient culture or by bicarbonate treatment. Chlorotic leaves had less chlorophyll per unit iron but had a greater dry weight per unit chlorophyll than green material. Chlorotic leaves were found to be reduced in both leaf area and dry weight compared with green ones, the reduction in dry weight being the greatest. Common root abnormalities were noted in chlorotic material induced by the above three methods.Evidence was produced which suggested that the difference between chlorosis-resistant and susceptible plants lay in qualitative differences in their iron transport compounds produced within the rootstock. Differential iron uptake was not suggested as a cause of the differences in behaviour. There was, however, evidence of a key role of the root iron pool in population differences in chlorosis susceptibility.Bicarbonate was found to suppress first iron uptake and then iron translocation. A possible causal role of the bicarbonate ion in lime-induced chlorosis was suggested through these effects and through its possible effect on the production of iron-transport compounds.