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Biomedical subjects

J Chauhan

Publications and source records attributed to J Chauhan.

16 recordsLinked to original sources
PubMed1991

Transcriptional regulation of the glucokinase gene by biotin in starved rats.

The purpose of this work was to investigate whether biotin, a water-soluble vitamin, regulates the glucokinase gene. Biotin was administered intraperitoneally to starved rats, and the time course of glucokinase induction was followed over a time period of 12 h. The glucokinase mRNA was increased 19.6-fold during the first 1 h after biotin administration, afterwards rapidly decayed, and was hardly detectable by 4 h. The amount of glucokinase activity as determined by conventional enzyme activity assay increased in a time-dependent fashion, reaching 4-fold by 2 h of biotin administration. The transcriptional activity of the gene as measured by a nuclear run-on assay was increased about 6.7-fold within 45 min of biotin administration. These findings indicate that biotin can regulate the glucokinase gene at the transcriptional stage in the starved rat.

Albumins↗
PubMed1989

Biotin.

Explore the source record for details and available documents.

Animals↗
PubMed1989

Taste discrimination of traditional and 'health' modified recipes.

Beef stew and sponge cake were prepared utilising traditional recipes and recipes modified in accordance with NACNE, National Advisory Committee on Nutrition Education guidelines (1983). Triangle tests were performed to determine whether subjects could discriminate between samples prepared using the traditional recipes. Thirty subjects (15 men and 15 women) participated. No significant differences could be established between the traditional and modified stew or sponge cake in terms of eating quality. Modification of traditional recipes by reducing sugar, fat and salt and increasing the fibre content without affecting the overall sensory quality that the consumer expects is an ideal way of achieving recommended dietary goals.

Adolescent↗
PubMed1989

Relationships between sour and salt taste perception and selected subject attributes.

The relationships between perceived sour and salt taste intensity and selected subject attributes--taste/smell deficits, salt use, avoidance of salt/sour tasting foods, smoking, alcohol use, dentures, education, and prescription drug use--were investigated in 180 subjects (30 men and 30 women/age group: 20 to 29 years [young], 70 to 79 years [old], 80 to 99 years [very old]. Multiple regression analyses showed that the taste intensity estimates were significantly related to age, sex, stimulus concentration, self-reported taste/smell deficits, avoidance of salt/sour tasting foods, salt use, alcohol, smoking, education, and use of certain drugs (drugs for the treatment of arthritis, drugs acting on the gastrointestinal tract and heart system, and diuretics/drugs for the treatment of hypertension). The very old showed deficits in perception of the low suprathreshold tastant levels, with near normal perception of the high levels, whereas the old exhibited deficits at all levels. Wearing dentures was the only single variable not selected in any of the final regression models, due to the high prevalence and homogeneity in use of dentures in the elderly groups. Further work using a stratified sample and a large number of subjects is warranted to elucidate the influence of subject attributes on taste perception.

Acids↗
PubMed1988

Role of human serum biotinidase as biotin-binding protein.

Biotinidase shows two binding sites for biotin, with Kd = 59 and 3 nM respectively, and requires tryptophan and cysteine residues of the biotinidase protein for biotin-binding activity. Analysis of human serum by various column-chromatographic techniques indicates that biotinidase is the only protein which exchanges with labelled (+)-biotin. It was shown previously that epileptic patients receiving a high average dose of anticonvulsants (containing a carbamide group) have lower biotin concentrations than those receiving a low dose. We have shown in human serum and with purified biotinidase that these anticonvulsant drugs compete with biotin for binding to the protein moiety.

Amidohydrolases↗
PubMed1988

Suprathreshold sour taste intensity and pleasantness perception with age.

Magnitude estimates for perceived intensity and pleasantness of suprathreshold concentrations of citric acid in solution and drink were examined in 180 healthy, free-living subjects divided into three groups: young (20-29 years), old (70-79 years) and very old (80-99 years). Psychophysical functions showed significant age effects. For both aqueous and food systems, the old gave higher intensity estimates to high acid concentrations and lower intensity estimates to low acid levels compared to the young and very old whose estimates were comparable. Sex had a significant effect on the intensity estimates with the women giving low acid levels lower estimates and high acid levels higher estimates than the men. All subjects gave low acid levels in solution lower intensity estimates than comparable drinks while at high concentrations, higher intensity estimates were given to solutions than drinks. Trend analysis of pleasantness estimates indicated significant age group differences. For both systems, the breakpoint, the acid level assigned the highest pleasantness estimate was lower for the young than for the elderly.

Adult↗
PubMed1987

Intestinal absorption of biotin and biocytin in the rat.

The uptake of biotin and biocytin was investigated in rat intestine using the everted sac technique. It has been shown that at biotin and biocytin concentrations less than 40 and 50 nM respectively, absorption proceeds by a saturable process, whereas at higher concentrations uptake by passive diffusion predominates. Fractionation of solubilized brush border preparations indicates that biotinidase is the only protein which binds biotin in this preparation.

Animals↗
PubMed1987

Age-related olfactory and taste changes and interrelationships between taste and nutrition.

This article critically reviews the literature on age-related olfactory and taste changes and the interrelationships between nutrition and taste. Age-related taste alterations are controversial, but there is consensus on an olfactory decline with age. Much of the age-related chemoreceptive research has used inappropriate methodology, thus leaving many findings inconclusive. Changes in the taste system with age may be related to nutrient intake, which in turn can be influenced by taste. Literature on such interrelationships is limited. Vitamins A, thiamin, B-6, B-12, folacin, zinc, and copper are thought to influence taste function. Moreover, those nutrients are of concern in the aged. The use of appropriate methodology is critical not only for the sensory but also for the nutritional aspects, particularly for qualitative and quantitative assessments of nutrient intakes. This review considers the experimental deficiencies (small sample size, inappropriate age range, inadequate psychophysical and stimuli presentation procedures, and poor dietary intake assessment) of studies reported in the literature and suggests major needs for research.

Aging↗
PubMed1986

Purification and characterization of human serum biotinidase.

Biotinidase has been purified from human serum to a specific activity of 1900 units/mg protein by a five-step procedure. After ammonium sulfate precipitation (33-55% cut) it was purified by DEAE-Sephacel, hydroxylapatite, octyl-Sepharose CL-4B, and Sephadex G-100 chromatography. The purified enzyme showed a single silver staining band with polyacrylamide gel electrophoresis under denaturing and non-denaturing conditions. Biotinidase is a glycoprotein. The sialic acid residues in the molecule are not required for enzyme activity. The Mr of human serum biotinidase estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Ferguson plot) and by sedimentation analysis was 68,000. Human serum biotinidase showed maximum activity in the pH range 6.0 to 7.5 with N-(d-biotinyl) p-aminobenzoate as substrate. However, with biocytin as substrate, the maximal activity of the enzyme was in the pH range 4.5 to 6.0. Using structural analogs of the substrate we have shown that biotinidase is not a general proteolytic enzyme and has specific structural requirements in the substrate for hydrolysis.

Amidohydrolases↗
PubMed1982

Determination of urinary amino acids by means of glass capillary gas-liquid chromatography with alkali-flame ionisation detection and flame ionisation detection.

The determination of amino acids as their N(O)-heptafluorobutyryl-isobutyl ester derivatives by glass capillary gas--liquid chromatography has been studied. Separations of amino acids obtained from insulin hydrolysate and human urine analysed with a flame ionisation detector, an alkali-flame ionisation detector and an electron-capture detector are shown. The quantitative results of urinary amino acids of one deep-sea diver are presented.

Adult↗
PubMed1980

Determination of homovanillic, isohomovanillic and vanillylmandelic acids in human urine by means of glass capillary gas-liquid chromatography with temperature-programmed electron-capture detection.

The determination of urinary homovanillic, isohomovanillic and vanillylmandelic acids as their trifluoroacetylhexafluoroisopropyl ester derivatives by glass capillary gas-liquid chromatography has been studied. It was shown that even with high column efficiencies a single peak-single compound relationship could not be assumed and for reliable quantitation it was necessary to check determinations with a second gas-liquid chromatography column.

Chromatography, Gas↗