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Biomedical subjects

J M McLaughlan

Publications and source records attributed to J M McLaughlan.

18 recordsLinked to original sources
PubMed1997

Interleukin-8 and inducible nitric oxide synthase mRNA levels in inflammatory bowel disease at first presentation.

Interleukin-8 (IL-8) and nitric oxide (NO) may be important mediators in the pathogenesis of chronic idiopathic inflammatory bowel disease (CIIBD), but their roles in disease activity in ulcerative colitis (UC) and Crohn's disease (CD) are uncertain. The aim of this study was to measure mRNA for IL-8 and inducible NO synthase (iNOS) in small mucosal biopsies from untreated patients at first presentation and to relate these measurements to the histological levels of polymorph infiltration graded on a ten-point scale. For this purpose, a sensitive enzyme-linked oligonucleotide chemiluminescent assay (ELOCA) was developed to quantitate reverse transcription-polymerase chain reaction (RT-PCR) products amplified from RNA from paired biopsy samples. The levels of IL-8 and iNOS mRNAs were calculated as ratios of the RT-PCR products to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) RT-PCR product. In UC patients, median values of IL-8/GAPDH and iNOS/GAPDH were significantly elevated compared with controls and CD. However, in both UC and CD, the IL-8/GAPDH and iNOS/GAPDH ratios correlated significantly with polymorph infiltration. ELOCA enabled quantitation of multiple mRNAs in small mucosal biopsies from untreated patients with CIIBD and supported a role for IL-8 and iNOS in acute inflammation in both UC and CD.

Adult↗
PubMed1980

Assessment of rat growth methods for estimating protein quality: interlaboratory study.

An interlaboratory study involving protein efficiency ratio (PER), net protein ratio (NPR), relative NPR (RNPR) and relative nitrogen utilization (RNU) was carried out. Six collaborators assayed 6 samples, including casein plus methionine which was used as a reference protein. Collaborators prepared their own diets and analyzed the diets for nitrogen. Test proteins were added at the 8% level (N X 6.25). PER values varied more than NPR values which varied more than either RNPR or RNU. RNU and RNPR produced almost identical values, but RNPR remains the official method of choice, because it is a well established method.

Animals↗
PubMed1978

The problem of curvature in slope assays for protein quality.

The dose-response curves in a valid slope--ratio assay must be linear and meet at the zero protein dose. However in rat bioassays at least 3 types of curvature are found when the method is applied to a wide range of samples; the types of curvature result from: 1) excessive protein 2) lysine deficiency and 3) threonine deficiency. Whole wheat flour which was limiting in lysine and threonine showed marked downward curvature after supplementation with threonine. It can be argued from these results that the slope ratio and relative protein value method underestimated the protein quality of lysine--deficient foods.

Amino Acids↗
PubMed1978

Nutrient levels of some foods of Eskimos from Artic Bay, N. W.T., Canada.

Native food samples of caribou, seal, and arctic char were collected from resident Eskimos in Arctic Bay, N.W. T., and analyzed for nutrients. Caribou and seal meats were similar in protein and fat content in comparison with beef. Arctic char was above the average in protein and fat content for fish. Ascorbic acid was present in significant amounts only in baby seal liver. Thiamin, riboflavin, vitamin B12, folacin, and pantothenic acid content ranged from average to high for seal and carbiou meat, respectively, in comparison to published values for pork and beef. The vitamin B6 content of caribou meat was comparable to average values reported for pork and beef but was lower in seal meat. Baby seal liver contained similar levels of thiamin, riboflavin, vitamin B12, folacin, and pantothenic acid and less vitamin B6 than those reported for pork, beef, calf, and lamb liver. Arctic char was not appreciably different in these vitamins from other fish. The iron content of the Eskimo foods was higher than the meat group of the mixed Canadian diet. The macro mineral nutrients in these foods were comparable to those in beef and fish. The amino acid composition of caribou and seal meat was similar to beef, except that seal meat had a lower content of sulfur-containing amino acids and a much higher content of histidine. The sample of seal and arctic char were relatively high in concentrations of long-chain unsaturated fatty acids.

Amino Acids↗
PubMed1977

Effects of threonine supplementation on the slope assay for protein quality.

Several diets considered to be marginally deficient in threonine were fed to young male rats at protein levels ranging from 3 to 9%. Protein sources included lactalbumin (reference standard), soy protein with added methionine, pea protein with added methionine, rice-casein, and peanut-sesame-fish. Chemical scores and plasma amino acid scores indicated that these diets were limiting in threonine at the 3--4% protein level; increased growth resulted from supplementation with threonine. After threonine supplementation, all protein sources except pea were limiting in lysine. Increased growth at low protein levels with little or no extra growth at high protein levels due to threonine supplementation resulted in decreased slopes in the relative protein value (RPV) assay. Consequently, threonine supplementation apparently decreased RPV values for these samples but the protein efficiency ratio was not affected. It was concluded that the RPV assay underestimates the protein quality of lysine-deficient proteins.

Animals↗
PubMed1976

Effect of a low-carbohydrate diet and alcohol on perceptual motor skill.

Eleven adults of both sexes ate a low-carbohydrate diet consisting mainly of meat, fish, and eggs for two days. After a low-carbohydrate breakfast on the third day, they operated a Stressalyzer to test their basic perceptual motor skill. Each subject drank 1.5 oz. rye whiskey at hourly intervals from 9:30 A.M. to 12:30 P.M. Blood glucose decreased to below 50 mg. per 100 ml. in three of the eleven subjects; two of the three had decreased perceptual motor skill.

Adult↗
PubMed1976

The relative nitrogen utilization method for evaluating protein quality.

A single-dose rat assay for protein quality called relative nitrogen utilization (RNU) is described. The method includes a factor for the protein utilized for maintenance. The protein quality of the test protein is expressed as a per cent of the value for lactalbumin, the reference protein. For good quality proteins RNU gives results that are similar to those obtained by net protein ratio and relative protein value; for poor quality proteins RNU results fall between values by the other 2 methods. The protein efficiency ratio (PER) gives much lower values for poor quality proteins than any of the other 3 aforementioned methods and is influenced more by both level of protein and lipid in the diet. RNU is a more precise assay then PER as judged by the coefficient of variation.

Body Weight↗