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Biomedical subjects

L A James

Publications and source records attributed to L A James.

18 recordsLinked to original sources
PubMed1998

Distribution of glutaminase and glutamine synthetase activities in the human gastrointestinal tract.

1. The activities of the two key enzymes involved in glutamine metabolism, glutaminase and glutamine synthetase, were measured in mucosal biopsies taken from different sites throughout the human gastrointestinal tract, from oesophagus to rectum. 2. The specific activity of glutamine synthetase was highest in the stomach (4.5 nmol glutamine formed per minute per mg of protein), but both small and large intestine and the oesophagus had little synthesizing capacity (less than 0.3 nmol of glutamine formed per minute per mg of protein). 3. Glutaminase specific activity was highest in the small intestine (53 nmol glutamate formed per minute per mg of protein by duodenal mucosa), intermediate in the large intestine and lowest in the oesophagus and stomach (less than 13 nmol of glutamate formed per minute per mg of protein). 4. The glutamine concentration in the mucosa was lower in the duodenum than in the colon (0.62 and 0.95 mmol/kg wet weight respectively), but both were much lower than the measured K(m) values of glutaminases obtained from these sites (3.8 and 4.0 nmol/kg wet weight respectively). 5. The concentration of glutamine in saliva, stomach juice, bile and duodenal juice suggests that very little glutamine passes into the gastrointestinal tract via these secretions. 6. The study provides the most complete information on the distribution of glutamine synthetase and glutaminase along the human gastrointestinal tract, and suggests that (i) both the small and large intestines have a high potential for glutamine metabolism, but little synthesizing capacity, thus both must derive their glutamine from other sources, and (ii) neither the stomach nor the oesophagus have a high glutaminase activity, although the stomach has substantial capacity to synthesize glutamine. The distribution of the enzymes along the gastrointestinal tract may help rationalize the use of glutamine for treating diseases that affect different parts of the gastrointestinal tract.

Adult↗
PubMed1998

Glutamine metabolism in the gastrointestinal tract of the rat assess by the relative activities of glutaminase (EC 3.5.1.2) and glutamine synthetase (EC 6.3.1.2).

The activities of the two key enzyme involved in glutamine metabolism, glutaminase (EC 3.5.1.2) and glutamine synthetase (EC 6.3.1.2), have been measured in the various tissues of the gastrointestinal (GI) tract of the rat, from the mouth to the rectum. Glutaminase activity was particularly high in the mucosa of the small intestine, where its activity accounted for more than 80% of the total activity of the GI tract. In contrast, the mouth and oesophagus had very low activities, accounting for less than 2% of the total. Glutamine synthetase was mainly confined to the lower part of the stomach, which accounted for almost 90% of the total activity of the GI tract. Activity in the small intestine was very low, accounting for less than 2% of the total, and similarly low levels were found in the mouth and oesophagus. The data provide the most complete information on the distribution of these enzymes in the GI tract of the rat and suggest: (a) that the mucosa of the small intestine has the highest capacity for glutamine breakdown but the lowest capacity for its synthesis, and so requires an external source of this amino acid; (b) that there is little potential for glutamine synthesis or breakdown in the mouth and oesophagus: and (c) that the lower stomach has a substantial capacity to synthesize glutamine, in contrast to the rest of the GI tract. The results of the investigation are relevant to sites of glutamine metabolism in therapeutic studies involving glutamine administration discussed with reference to reports of the effects of glutamine administration on GI tract injury.

Animals↗
PubMed1997

Comparative genomic hybridisation of ductal carcinoma in situ of the breast: identification of regions of DNA amplification and deletion in common with invasive breast carcinoma.

Comparative genomic hybridisation has been used to map copy number changes in nine cases of ductal carcinoma in situ of the breast obtained from wax-embedded archive material. A wide variety of abnormalities were detected including gain of regions of 1q, 17q, 19q, 20p and 20q and loss on 13q, 14q, 17p, 16q and 22q. Amplification of areas on 10p, 8q and 20q were also observed. Chromosomal alterations were more frequent in higher grade DCIS and closely resemble those previously detected in invasive breast cancer using the same technique. These data provide strong molecular support for the view that DCIS is a precursor lesion of invasive breast carcinoma.

Aged↗
PubMed1996

Walking, cloning, and mapping with YACs in 3q27: localization of five ESTs including three members of the cystatin gene family and identification of CpG islands.

Using yeast artificial chromosomes, we have generated a high-resolution physical map for 2.7 Mb of human chromosomal region 3q27. The YAC clones group into three contigs, one of which has also been linked to the CEPH YAC contig map of human chromosome 3. Fluorescence in sity hybridization has been used to order the contigs on the chromosome and to estimate the distance between them. Expressed sequence tags for five genes, including three members of the cystatin gene family and a gene thought to be involved in B-cell non-Hodgkin lymphoma, have been placed within the YAC contigs, and 12 putative CpG islands have been identified. These YACs provide a useful resource to complete the physical mapping of 3q27 and to begin identification and characterization of further genes that are located there.

Base Composition↗
PubMed1990

Physical mapping around the Alzheimer disease locus on the proximal long arm of chromosome 21.

Evidence from linkage studies suggests that familial Alzheimer disease (AD) can be caused by a defect in a gene on the proximal long arm of chromosome 21. We have constructed a physical map spanning 10 megabases of this region of the chromosome by means of pulsed-field gel electrophoresis and analysis of somatic cell hybrids. Our data have allowed us to establish the order of chromosome 21 loci--cen-(S16,S48)-S13-S46-S4-(S52,S110)-(S1,S1 1)--and are thus of immediate relevance both to multipoint linkage analysis in families affected by AD and for moving from this linkage to the isolation of the genetic defect. We have also been able to identify several CpG-rich sequences close to the four most centromeric loci, suggesting the location of genes in this region. These probes, which are all within 1.5 megabases of one another, are currently the markers most tightly linked to the AD locus. Genes identified in this region can therefore be considered as candidates for the disease locus.

Alzheimer Disease↗
PubMed1989

Predisposing locus for Alzheimer's disease on chromosome 21.

Linkage between Alzheimer's disease and markers on the long arm of chromosome 21 was investigated in six families affected by disease of early onset. Linkage was confirmed and the disease locus shown to be centromeric to the locus D21S1/S11 on the long arm of the chromosome. It is argued that the data are consistent with the notion that all patients with Alzheimer's disease of genetic aetiology have a predisposing locus on chromosome 21.

Adult↗
PubMed1987

Primary structure around the lipoate-attachment site on the E2 component of bovine heart pyruvate dehydrogenase complex.

Bovine heart pyruvate dehydrogenase complex was acetylated by using [3-14C]pyruvate in the presence of N-ethylmaleimide, with approx. 1 mol of acetyl groups being incorporated per mol of E2 polypeptide. After peptic digestion, lipoate-containing peptides were purified by high-voltage electrophoresis and ion-exchange and reverse-phase h.p.l.c. The amino acid sequence around the lipoic acid-attachment site of E2 was determined by automated Edman degradation. Acetylation of a lipoate cofactor bound to a lysine residue was verified by fast-atom-bombardment m.s.

Acetylation↗
PubMed1981

Protein phosphorylations in poliovirus infected cells.

In vivo phosphorylation of proteins that are associated with polysomes of poliovirus-infected VERO (African green monkey kidney) and HeLa (Henrietta Lacks) cells differed from phosphorylations observed with uninfected cells that were fed fresh medium. With both types of cells infection stimulated phosphorylation of proteins with molecular weights of 40 000-41 000, 39 000, 34 000, 32 000, and 24 000. Similarities of phosphorylations in VERO and HeLa cells suggest that they are a specific consequence of infection and might serve a regulatory function during protein synthesis.

Animals↗
PubMedDate not supplied

Breast-feeding.

Explore the source record for details and available documents.

Breast Diseases↗
PubMedDate not supplied

Effectiveness of low dose erythropoietin: a possible advantage of high flux hemodialysis.

Recombinant human erythropoietin (EPO) was administered to 32 stable out-patients with end-stage renal disease (ESRD) on a priority basis three times a week. All patients underwent dialysis with polysulfone hollow fiber dialyzers. Mean time-averaged blood urea nitrogen (BUN) value was 50 +/- 12 mg/dl, and Kt/V for urea was 1.20 +/- 0.34/dialysis. The initial dose of EPO was 2,800 +/- 950 U/dialysis (45 +/- 17 U/kg/dialysis). The maintenance dose averaged 2,500 U/dialysis. Within the mean time of observation, 15 +/- 4 weeks, all but one patient responded to EPO by eliminating transfusion requirements, and 29 of 32 achieved the target hematocrit of 30-33%. For patients with hematocrits below 25% before EPO, the increase averaged 1.6 +/- 0.8%/week. The dose of EPO was lower and the hematocrit response was higher than reported previously. The rate of increase in hematocrit did not correlate with small molecular weight solute removal. Mean red blood cell survival was 52 +/- 18 days. No adjustments in blood pressure (BP) medications or dry weight were required to control BP. These data and earlier experiences with recovery from the anemia of ESRD after more effective dialysis suggest that the bone marrow response to EPO may be augmented by high flux hemodialysis.

Adolescent↗
PubMedDate not supplied

Orientation through self-study.

Traditional orientation programs and schedules did not meet the needs of new nurses seeking employment at one small hospital. The orientation class content was redesigned into self-study modules. This approach allowed greater flexibility in the start date for orientees, the orientation schedule, and the rate at which the content was covered.

Education, Nursing, Continuing↗