PubMed Health⌕ Search

Biomedical subjects

G Barnes

Publications and source records attributed to G Barnes.

At least 19 recordsLinked to original sources
PubMed1992

Sequence-tagged sites (STSs) spanning 4p16.3 and the Huntington disease candidate region.

The generation of sequence-tagged sites (STSs) has been proposed as a unifying approach to correlating the disparate results generated by genetic and various physical techniques being used to map the human genome. We have developed an STS map to complement the existing physical and genetic maps of 4p16.3, the region containing the Huntington disease gene. A total of 18 STSs span over 4 Mb of 4p16.3, with an average spacing of about 250 kb. Eleven of the STSs are located within the primary candidate HD region of 2.5 Mb between D4S126 and D4S168. The availability of STSs makes the corresponding loci accessibility to the general community without the need for distribution of cloned DNA. These STSs should also provide the means to isolate yeast artificial chromosome clones spanning the HD candidate region.

Base Sequence↗
PubMed1992

Assay by polymerase chain reaction (PCR) of multi-allele polymorphisms in the Huntington's disease region of chromosome 4.

The Huntington's disease-linked D4S115 marker has been converted from a DNA blot assay to a more sensitive and rapid polymerase chain reaction (PCR) assay. PCR amplification of a tandem repeat at D4S115 revealed 7 allelic fragments, ranging in size from approximately 610 to 915 bp, differing in their apparent copy number of a approximately 55 bp core repeat. This repeat unit differs strikingly in sequence from the repeat units of other multi-allele markers from chromosome region 4p 16.3, arguing that the VNTR (Variable Number of Tandem Repeats) loci clustered in this region did not arise from a common ancestral sequence. The D4S115 marker can be assayed simultaneously with PCR products from D4S125, D4S95 and D4S43 on a single agarose gel, providing a rapid scan for successful amplification of these difficult-to-assay VNTRs, and for inheritance of the entire candidate Huntington's disease region. This approach should help to increase the speed, informativeness and accuracy of presymptomatic and prenatal linkage testing in this devastating disorder.

Alleles↗
PubMed1992

The Huntington's disease candidate region exhibits many different haplotypes.

Analysis of 78 Huntington's disease (HD) chromosomes with multi-allele markers revealed 26 different haplotypes, suggesting a variety of independent HD mutations. The most frequent haplotype, accounting for about one third of disease chromosomes, suggests that the disease gene is between D4S182 and D4S180. However, the paucity of an expected class of chromosomes that can be related to this major haplotype by assuming single crossovers may reflect the operation of other mechanisms in creating haplotype diversity. Some of these mechanisms sustain alternative scenarios that do not require a multiple mutational origin for HD and/or its positioning between D4S182 and D4S180.

Alleles↗
PubMed1992

Yeast proteins associated with microtubules in vitro and in vivo.

Conditions were established for the self-assembly of milligram amounts of purified Saccharomyces cerevisiae tubulin. Microtubules assembled with pure yeast tubulin were not stabilized by taxol; hybrid microtubules containing substoichiometric amounts of bovine tubulin were stabilized. Yeast microtubule-associated proteins (MAPs) were identified on affinity matrices made from hybrid and all-bovine microtubules. About 25 yeast MAPs were isolated. The amino-terminal sequences of several of these were determined: three were known metabolic enzymes, two were GTP-binding proteins (including the product of the SAR1 gene), and three were novel proteins not found in sequence databases. Affinity-purified antisera were generated against synthetic peptides corresponding to two of the apparently novel proteins (38 and 50 kDa). Immunofluorescence microscopy showed that both these proteins colocalize with intra- and extranuclear microtubules in vivo.

Alkaloids↗
PubMed1992

A novel G protein-coupled receptor kinase gene cloned from 4p16.3.

Within the Huntington's disease (HD) candidate region of 4p16.3, the D4S127 locus displays strong linkage disequilibrium with the defect and anchors a conserved haplotype found on many HD chromosomes. To isolate genes from this region we have applied the exon amplification technique to overlapping cosmids spanning D4S127. Here, we report the discovery of a new gene encoding a novel member of a family of protein kinases that specifically phosphorylate the activated forms of G protein-coupled receptors. Such kinases are thought to participate in desensitization of specific receptors, thereby blocking further signal transduction. This gene must now be carefully scrutinized to determine whether it might be involved in HD.

Amino Acid Sequence↗
PubMed1992

Eye tests in the elderly: factors associated with attendance and diagnostic yield in non-attenders.

Patients aged 60-75 years registered with one inner city general practice were sent a questionnaire asking when they last received an eye check by an optometrist. Of the 193 (77%) who responded, 110 (59%) had attended in the last 2 years, and 138 (74%) in the last 3 years. Males and those with mobility problems were less likely to have had their eyes checked. Seventy-seven previous non-attenders were offered an appointment with an optometrist and this was accepted by 34 (44%). These individuals showed a high level of ophthalmic morbidity. Discussion of optometric checks should be included in general practice health checks and the elderly surveillance programme.

Aged↗
PubMed1992

A recombination event that redefines the Huntington disease region.

We report both a recombination event that places the Huntington disease gene proximal to the marker D4S98 and an extended linkage-disequilibrium study that uses this marker and confirms the existence of disequilibrium between it and the HD locus. We also report the cloning of other sequences in the region around D4S98, including a new polymorphic marker R10 and conserved sequences that identify a gene in the region of interest.

Chromosomes, Human, Pair 4↗
PubMed1978

Release of phospholipase A and triglyceride lipase from rat liver.

A new, rapid, and sensitive assay for phospholipase A, utilizing commercially available [14C]phosphatidylethanolamine with 14C label in both palmitic acid moieties, was used to study phospholipase A release from perfused liver, hepatocytes, and intestinal cells from rats. Heparin triggered a prompt release of phospholipase A from perfused liver. Phospholipase A and triglyceride lipase were released from hepatocytes at a linear rate for 1 h and 30 min, respectively. Heparin (20 u/ml) doubled the release of phospholipase A and triglyceride lipase from hepatocytes. Colchicine (0.1 mM), but not puromycin (0.2 mM), inhibited basal and heparin-stimulated phospholipase A release by 40%. Since the amount of phospholipase A and triglyceride lipase released into the medium greatly exceeded intracellular activities, it is possible that secretion is coupled with intracellular conversion from inactive to active forms of the enzymes. Dibutyryl cyclic AMP (1 mM) inhibited phospholipase A (48%) and triglyceride lipase (82%) release from hepatocytes. Epinephrine, dexamethasone, and clofibrate inhibited release of triglyceride lipase but not phospholipase A. Phospholipase A activity of intestinal cells was greater than in hepatocytes, but neither heparin nor dibutyryl cyclic AMP affected phospholipase A release from intestinal cells. These results suggest that the liver is a major source of phospholipase A of postheparin plasma. The fact that dibutyryl cyclic AMP affects the release of these enzymes suggests an additional mechanism for hormonal regulation of lipid and lipoprotein metabolism.

Animals↗
PubMed1978

Nurse specialists in family planning: the results of a 3-year study.

In the first three years of a Nurse Specialist Clinic in Family Planning, 1422 new patients were seen. Oral contraception (OCs) was dispensed for 638 patients, 548 intrauterine devices (IUDs) were fitted and 126 patients received an injectable contraceptive. The continuation rate at thirty months was, 73.2 for OCs, and 68.6 for IUDs. The additional training received by the nurse specialists allowed them to practice comprehensive family planning safely and effectively, as shown by the low "problem" rate, 9.1% for OCs and 7.2% for IUDs. Continued use effectiveness, as shown by the second choice of contraception initiated in the clinic for those who stopped using their first method, was also high, 81.5% for OCs and 90.5% for IUD closures.

Contraceptive Agents↗
PubMed1978

Exploration of selected brachial plexus lesions by the posterior subscapular approach.

The application of an old surgical technique, previously employed for treatment of thoracic outlet syndromes, to lesions of the brachial plexus is discussed. Positioning of the patient, the surgical procedure, and selected indications for a posterior subscapular approach with resection of the first rib are discussed. The indications for the use of this approach are: proximal plexus lesions involving roots and/or trunks believed to be repairable, complicated thoracic outlet syndromes, prior anterior exploration for vascular or nervous structure disease, and progressive plexus palsy associated with damage to the soft tissue of the anterior chest wall and supraclavicular regions secondary to irradiation. The authors' experience to date with 12 such cases is presented in chart form, while five cases are presented in some detail.

Adolescent↗
PubMed1976

Nurse specialist in family planning.

In an experimental clinic, run by nurse specialists in family planning, a total of 768 patients were seen in the first year. Oral contraception was dispensed for 377 patients and 187 intrauterine devices (IUCDs) were inserted; a further 204 IUCD patients attended only for follow-up visits. All side effects were adequately diagnosed by the nurse specialist.

Community Health Services↗
PubMed1975

Sudden death in patients evaluated for ischemic heart disease.

Data from 981 patients evaluated for ischemic heart disease with coronary angiography were reviewed to identify variables predictive of sudden death and duration from onset of symptoms to death. During the period of follow-up, 113 patients died. Of these deaths, 99 were classified as cardiovascular. Forty percent occurred within 1 hour of onset of symptoms, 34% within 24 hours, and 25% in greater than 24 hours. Patients prone to sudden death were characterized as having severe multiple-vessel disease in combination with left ventricular dysfunction and disturbances in intraventricular conduction and rhythm. The best five-variable model to predict sudden death in these patients included the following variables: number of vessels greater than or equal to 70% obstructed (P less than .001); therapeutic requirement of inotropic (P less than .003) and diuretic (P less than .006) drugs; premature beats (P less than .006); and ventricular conduction defects (P less than .008). Additional variables were related significantly to the duration of the terminal episode. These data are preliminary, but indicate the possibility of identifying patients prone to sudden death.

Age Factors↗