Clinical trial of chromium and yeast supplements on carbohydrate and lipid metabolism in diabetic men

Chromium (Cr) deficiency in experimental animals and in humans sustained by prolonged total parenteral nutrition has been shown to cause diabetes mellitus. Prior trials in humans indicated that Cr supplements, in either inorganic or organic form, may improve carbohydrate utilization. We report here a clinical double-blind, random cross-over trial of inorganic chromium trichloride, a brewer’s yeast that contained Cr as glucose-tolerance-factor (GTF), a brewer’s yeast extract without GTF, and a placebo. Forty-three outpatient diabetic men received three of these supplements for 4 months each. Subgroups included 21 ketosis-prone, 7 ketosis-resistant non-obese, and 15 ketosis-resistant obese men. Cr levels were followed pre- and post-treatment in hair, red blood cells, plasma, and urine. Response of carbohydrate metabolism to treatment was assessed in terms of change in insulin requirements, fasting plasma glucose, plasma cholesterol, and triglycerides, as well as the change in plasma glucose, glucagon, and insulin or C-peptide levels in response to a standard meal. In some men, these parameters were also measured after iv tolbutamide. Both the inorganic and organic oral Cr supplements increased measurable body pools of Cr in hair and red blood cells by about 25%. However, fasting plasma glucose and lipids and the glucose response to either the standard meal or to tolbutamide were not significantly altered by any of the treatments.     

Experimental allergic encephalomyelitis in congenic strains of mice

Inbred mice and lines congenic to them for the major histocompatibility complex were similar in susceptibility to EAE except for moderate differences in two pairs. TheH-2 haplotypesq, s, andb occurred in inbred strains and in congenic lines of high, medium, or low susceptibility. It is concluded that the major histocompatibility complex does not control susceptibility to EAE in mice. Furthermore, the low susceptibility of DBA/1J mice was not enhanced by poly A-U.     

Effects of gradual expansign on arterial stenosis

The blood flow through an arterial stenosis can theoretically be increased by gradual expansion of the stenosis. This hypothesis was tested by comparing the flow through abruptly expanding and gradually expanding stenosed plastic conduits. The conduits were tested in non-pulsatile flow with water and bank blood and in pulsatile flow in dog's descending aorta. It was found that:

1. (a)
   The pressure drop in arterial stenoses is larger than that predicted by non-pulsatile theory.     

A substrate-mediated assay of bacterial proton efflux/influx to predict the degree of spoilage of beef mince stored at chill temperatures

A method was developed to predict spoilage of minced meat at chill temperatures, based on the difference in proton efflux from and influx into bacterial cells. This difference depends on the number of organisms present, the available glucose in the meat sample and the ability of the organisms to metabolize amino acids. The proton efflux/influx of a meat filtrate containing bacteria was measured at 25°C with a pH/ion meter in the presence of peptone with or without glucose. There was a noticeable rate of change of mV h_-1 of the meat filtrate prior to the organoleptic detection of spoilage which may be used semi-predictively to determine the remaining shelf-life of meat at different storage temperatures. The method could be investigated further, encompassing type and relative numbers of organisms, incubation temperature, meat type and composition (i.e. available glucose) to produce a spoilage prediction model. The method does not require sophisticated equipment, only a standard pH/ion meter, is cheap, needing only peptone and glucose, is relatively simple, and takes less than 2 h to perform.     

Thermal denaturation and loss of viability in Escherichia coli and Bacillus stearothermophilus

When Escherichia coli was heated at 10°C/min in a differential scanning calorimeter, the onset of irreversible thermal denaturation occurred at 51°C, about 5°C above the maximum growth temperature. The temperature at which death rate was maximal (63°C) coincided with the thermogram peak caused by denaturation of the 30S ribosomal subunit. The maximum death rate in vegetative cells of Bacillus stearothermophilus occurred at the higher temperature of 71°C which also coincided with the leading edge of the main thermogram peak.     

Tomato exo-(1-->4)-beta-D-galactanase. Isolation, changes during ripening in normal and mutant tomato fruit, and characterization of a related cDNA clone.

An exo-(1-->4)-beta-D-galactanase was isolated from ripe tomato fruit (Lycopersicon esculentum Mill. cv Ailsa Craig and cv Better Boy) using anion-exchange, gel filtration, and cation-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the most active fraction revealed a predominant protein band at 75 kD and several minor bands. A 30-amino acid N-terminal sequence from this 75-kD protein showed a high degree of homology with other recently identified beta-galactosidase/ galactanase proteins from persimmon and apple fruits (I.-K. Kang, S.-G. Suh, K.C. Gross, J.-K. Byun [1994] Plant Physiol 105: 975-979; G.S. Ross, T. Wegrzyn, E.A. MacRae, R.J. Redgwell [1994] Plant Physiol 106: 521-528) and with the predicted polypeptide sequence encoded by the ethylene-regulated SR12 gene in carnation (K.G. Raghothama, K.A. Lawton, P.B. Goldsbrough, W.R. Woodson [1991] Plant Mol Biol 17: 61-71). The enzyme focused to a single band of beta-galactosidase activity on an isoelectrofocusing gel at pH 9.8. The enzyme was specific for (1-->4)-beta-D-galactan substrates with a pH optimum of 4.5. The only reaction product detected was monomeric galactose, indicating that the enzyme was an exo (1-->4)-beta-D-galactanase. beta-Galactanase activity increased at the onset of ripening in normal fruit, but no similar increase was detected in the nonripening mutants nor and rin. A tomato homolog (pTombetagal1) was isolated using the SR12 cDNA clone from carnation as a probe. This clone showed 73% identify at the amino acid level with beta-galactosidase-related sequences from apple and asparagus and 66% identity with SR12. pTombetagal1 is a member of a gene family. Northern analysis demonstrated that pTombetagal1 expression was ripening related in normal fruits, with lower levels apparent in the nonsoftening mutants.     

Peptide modification by introduction ofα-trifluoromethyl substituted amino acids

Summary Methodology for the synthesis and incorporation of-trifluoromethyl substituted amino acids into N- and C-terminal position of peptides is described. The incorporation of-trifluoromethyl substituted amino acids into strategical positions of peptides enhances proteolytic stability and lipophilicity. Furthermore, it improves transport rates in vivo and permeability through certain body barriers.