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Biomedical subjects

M Price

Publications and source records attributed to M Price.

At least 19 recordsLinked to original sources
PubMed1992

Effect of diet on posttransplant hyperlipidaemia.

Twenty-five patients with a renal transplant for 15 months to 19.4 years, hyperlipidaemia and stable graft function underwent three months of dietary management. Plasma lipid and apolipoprotein concentrations and lipoprotein electrophoresis were measured after a 12 hour fast at enrollment and after three months of diet. The aims of diet were to reduce energy intake in the overweight, restrict fat to 25-30% of total intake, reduce saturated fat content to less than 10% of total energy and cholesterol to less than 300 mg/d. After three months of diet there was a significant fall in mean cholesterol/HDL cholesterol risk ratio and a rise in mean HDL cholesterol concentration. Six patients reverted to a normal lipoprotein electrophoretic pattern with a significant reduction in mean total cholesterol, LDL cholesterol, cholesterol/HDL cholesterol ratio, apoprotein B and apoB/apo A-1 ratio. Most of the other patients who made dietary modifications showed some improvement in their lipid parameters. Dietary modification should be the initial approach to the management of posttransplant hyperlipidaemia.

Adult↗
PubMed1992

Regional expression of the homeobox gene Nkx-2.2 in the developing mammalian forebrain.

A novel mouse homeobox-containing gene, Nkx-2.2, has been isolated. Nkx-2.2 is a member of a family of genes whose homeodomains are homologous to that of the Drosophila NK-2 gene. Nkx-2.2 transcripts are found in localized domains of the brain during mouse embryogenesis. Nkx-2.2 expression in the brain abuts and partially overlaps with the expression domains of two other related homeobox-containing genes, TTF-1 and Dlx. The expression domains of the three genes in the developing prosencephalon coincide with anatomical boundaries, particularly apparent in the diencephalon. This result raises the possibility that these genes may specify regional differentiation of the developing diencephalon into its anatomically and functionally defined subregions. Nkx-2.2 may be involved in specifying diencephalic neuromeric boundaries.

Animals↗
PubMed1992

Ecological effects of short-term ciprofloxacin treatment of travellers' diarrhoea.

Forty-two subjects travelling to Mexico for 11 days were enrolled in a randomized, double-blind, placebo-controlled trial comparing ciprofloxacin 250 mg twice daily for three days or placebo for treatment of travellers' diarrhoea. Seventeen (41%) subjects were randomized to treatment. By the last treatment day, all seven evaluable subjects in the ciprofloxacin group, and three of eight evaluable subjects in the placebo group were cured (P = 0.04). The mean time to cure was 26 h for ciprofloxacin and 60 h for placebo-treated patients (P = 0.03). Faecal specimen were collected pre-travel, after four days in Mexico, 48 h post-travel and four weeks post-travel. Potentially pathogenic Escherichia coli strains carrying diarrhoeagenic virulence genes were detected by DNA hybridization tests, during or after travel, in 41% of treated and 31% of asymptomatic travellers. Travel, irrespective of diarrhoea and type of treatment, had a minor impact on the aerobic and anaerobic microflora. In travellers with ongoing diarrhoea, a suppression of the numbers of anaerobic bacteria was found, but the microflora was otherwise virtually unaffected. Significantly increased frequencies of E. coli resistant to ampicillin, doxycycline, chloramphenicol and co-trimoxazole were found during and after travel in all categories of travellers, though more frequently in subjects who experienced diarrhoea. The susceptibility of Bacteroides spp. remained unchanged. The sensitivity of E. coli to ciprofloxacin was not affected by travel, except in four ciprofloxacin-treated subjects who acquired multiresistant E. coli with ciprofloxacin MICs of > or = 0.125 mg/L post-travel. Bacteroides strains with MICs of > or = 64 mg/L were isolated post-travel from four ciprofloxacin-treated patients, and from one of the other 34 travellers not treated with ciprofloxacin.

Administration, Oral↗
PubMed1992

Human lumbar vertebrae. Quantitative three-dimensional anatomy.

This study details the quantitative three-dimensional surface anatomy of human lumbar vertebrae based on a study of 60 vertebrae. The two lower vertebrae (L4 and L5) appeared to be transitional toward the sacral region, whereas the upper two vertebrae (L1 and L2) were transitional toward the thoracic region. Means and standard errors of the means for linear, angular, and area dimensions of vertebral bodies, spinal canal, pedicle, pars interarticularis, spinous and transverse processes were obtained for all lumbar vertebrae. This information provides a better understanding of the spine, and allows for a more precise clinical diagnosis and surgical management of spinal problems. The information is also necessary for constructing accurate mathematical models of the human spine.

Cadaver↗
PubMed1992

Expression of the murine Dlx-1 homeobox gene during facial, ocular and limb development.

We have analysed the expression pattern of the mouse homeobox containing gene Dlx-1. This gene harbors a homeodomain related to that found in the Drosophila distal-less (dll) gene. In addition to its expression in the developing forebrain, Dlx-1 is transcribed in several structures containing cells of neural crest origin such as the facial mesenchyme and various elements of the peripheral nervous system. Dlx-1 transcripts are also detected in the differentiating retina and during limb morphogenesis, in the apical ectodermal ridge. The possible involvement of Dlx-1 during facial, ocular and limb development is discussed.

Animals↗
PubMed1992

Examination of potato virus X proteins synthesized in infected tobacco plants.

Nucleotide sequence analysis of potato virus X (PVX) genomic RNA predicts five open reading frames (ORFs). Previous analysis of total RNAs from PVX-infected leaf tissue suggested that six subgenomic RNAs are synthesized during infection. However, the proteins encoded by the genomic RNA, the subgenomic RNAs, or the predicted ORFs have not been identified in vivo. To characterize the coding properties of the viral RNA, particularly to determine whether the five predicted ORFs function in vivo, total protein extracts prepared from PVX-infected leaf tissue were analyzed by using antibodies raised against virus-specific synthetic peptides and against the virus capsid protein. Dot blot analyses showed that these antibodies reacted to PVX-infected extracts, indicating in vivo expression of the five predicted ORFs. In addition, Western blot (immunoblot) analysis of the extracts showed that ORF 1, 2, 3, and 4 peptide antisera and coat protein antiserum detect predominantly a single protein.

Amino Acid Sequence↗
PubMed1992

Cell-type-specific expression of the rat thyroperoxidase promoter indicates common mechanisms for thyroid-specific gene expression.

A 420-bp fragment from the 5' end of the rat thyroperoxidase (TPO) gene was fused to a luciferase reporter and shown to direct cell-type-specific expression when transfected into rat thyroid FRTL-5 cells. Analysis of this DNA fragment revealed four regions of the promoter which interact with DNA-binding proteins present in FRTL-5 cells. Mutation of the DNA sequence within any of these regions reduced TPO promoter activity. The trans-acting factors binding to these sequences were compared with thyroid transcription factor 1 (TTF-1) and TTF-2, previously identified as transcriptional activators of another thyroid-specific gene, the thyroglobulin (Tg) gene. Purified TTF-1 binds to three regions of TPO which are protected by FRTL-5 proteins. Two of the binding sites overlap with recognition sites for other DNA-binding proteins. One TTF-1 site can also bind a protein (UFB) present in the nuclei of both expressing and nonexpressing cells. TTF-1 binding to the proximal region overlaps with that for a novel protein present in FRTL-5 cells which can also recognize the promoter-proximal region of Tg. Using a combination of techniques, the factor binding to the fourth TPO promoter site was shown to be TTF-2. We conclude, therefore, that the FRTL-5-specific expression of two thyroid restricted genes, encoding TPO and Tg, relies on a combination of the same trans-acting factors present in thyroid cells.

Animals↗
PubMed1991

A mouse gene related to Distal-less shows a restricted expression in the developing forebrain.

Many genes known to be involved in embryogenesis and morphogenesis of the fruitfly Drosophila melanogaster encode proteins with a highly conserved region of 60 amino acids called the homeodomain. Mammalian counterparts for most of these genes have been identified, including those homologous to the Drosophila homeotic genes or to genes such as evenskipped, engrailed or caudal. We have isolated a murine homeobox gene that encodes a homeodomain similar to that encoded by the Drosophila Distalless (Dll) gene. Dll has a crucial role in Drosophila limb morphogenesis, partially specifying pattern along the proximo-distal axis of the limb. The murine counterpart is expressed in a restricted region of the developing brain, within the diencephalon and the adjacent telencephalic regions.

Amino Acid Sequence↗
PubMed1991

Characterization of high affinity binding sites for charybdotoxin in human T lymphocytes. Evidence for association with the voltage-gated K+ channel.

Charybdotoxin (ChTX) inhibits with high affinity a voltage-gated K+ channel that is present in human T lymphocytes. In this system, 125I-ChTX binds specifically and reversibly to a single class of sites which display a Kd of 8-14 pM, as measured by either equilibrium or kinetic binding protocols. The maximum density of sites, 542 sites/cell, correlates well with the density of K+ channel as determined by electrophysiological experiments. Binding of 125I-ChTX is modulated by the ionic strength of the incubation media and by Ca2+. Increasing concentrations of either K+, Na+, or Ca2+ cause inhibition of toxin binding. Inhibition of binding by Ca2+ is due, primarily, to an effect on toxin dissociation rates. Increasing the pH of the external media from 6.8 to 8.5 enhances toxin binding, due to an increase in affinity with no significant effect on the maximum density of receptor sites. Different agents that block the voltage-gated K+ channel in human T lymphocytes, inhibit toxin binding. Mitogen-stimulated T cells display 2.5-3-fold increase in toxin binding as compared with unstimulated control cells. These data, taken together, suggest that 125I-ChTX binding sites identified in this study, represent the predominant voltage-gated K+ channel present in peripheral human T lymphocytes. Therefore, 125I-ChTX is a useful probe for elucidating the physiological role of this type of K+ channel.

Binding Sites↗
PubMed1991

Differential effects of alveolar and arterial oxygen tension on pulmonary vasomotor tone in ECMO-perfused, isolated piglet lungs.

Hypoxia is a known stimulant of pulmonary hypertension. We hypothesized graded effects of alveolar (PAO2) and arterial (PaO2) oxygen tension on pulmonary vascular resistance (PVR). A standard in situ, isolated lung preparation was modified by adding an oxygenator to the perfusion circuit with cannulation of the unarrested heart, allowing control of PAO2 and PaO2 in lungs devoid of ischemic injury. Seven anesthetized piglets were prepared with occlusive tracheostomy, ductus arteriosus ligation, and cannulation of the left atrium and main pulmonary artery. Animals were exsanguinated while simultaneously perfusing the lungs with a donor-blood primed extracorporeal membrane oxygenation circuit. Flow, left atrial pressure, pH, and PCO2 were kept constant. PAO2 and PaO2 were altered to establish four different experimental conditions as described by a latin square. PVR was calculated from measurements of pulmonary artery pressure (PAP) before and after introducing an experimental condition. Results show that (1) alveolar hypoxia significantly increases PVR despite arterial hyperoxia; (2) alveolar hypoxia is a more potent stimulus of pulmonary vasoconstriction than arterial hypoxemia; (3) alveolar and arterial oxygen tension are independent, additive effectors of PVR; and (4) recovery from acute hypoxic pulmonary vasoconstriction may be more sensitive to alveolar oxygen tension.

Animals↗
PubMed1991

The transcription factor TTF-1 is expressed at the onset of thyroid and lung morphogenesis and in restricted regions of the foetal brain.

TTF-1, a homeodomain-containing transcription factor, which is required for the specific expression of the thyroglobulin and thyroperoxidase gene promoters in differentiated thyroid cell lines, is expressed at the very beginning of rat thyroid differentiation. TTF-1 mRNA is detected in the endodermal cells of the thyroid rudiment in the rat embryo and precedes the expression of the two known target genes by 5 days. No delay is observed between the appearance of TTF-1 mRNA and protein, which shows a clear nuclear localization. In the adult thyroid, TTF-1 is present only in the endoderm-derived follicular cells. Two additional domains of expression of TTF-1 have been observed, the lung and restricted areas of the brain. In the lung, TTF-1 mRNA and protein are also present at the earliest stages of differentiation and are later confined to the bronchial epithelium. In the brain, TTF-1 appears to be restricted to structures of diencephalic origin, including the developing neurohypophysis. The early detection of TTF-1 in the endodermal cells of the thyroid and lung anlage and in restricted neuroblast populations indicates that TTF-1 may have a role in cell determination in these three systems and that additional mechanisms may be involved in the activation of thyroid-specific gene expression.

Animals↗
PubMed1991

Private health care in South Africa: should the unions intervene?

The South African state's policy of privatization of health services has led to deterioration of public-sector health care and increased costs of access to this sector. This has generated an increasing demand for private health insurance among the predominantly black organized working class. These demands pose a dilemma for the progressive trade unions; negotiation of private-sector health insurance will have deleterious consequences for the equity and efficiency of the health services in general. Current trends in the private health sector also indicate that rapid cost increases will make most regular insurance packages unaffordable to the majority of workers within a few years. On the other hand, trade unions are obliged to meet the material demands of their members, and to intervene to stem the flow of individual workers to the private health sector. This article describes these trends, and the authors argue the case for intervention in this process by trade unions, in the form of union-negotiated and union-controlled "managed care" schemes. Such schemes will allow for the delivery of an adequate and appropriate package of health services at affordable rates. Union control will also allow for such structures to become the building blocks of a future national health service, and for incorporation into that service. Finally, the political implications of such interventions are addressed. The authors argue that the potential for undermining broader political campaigns and for creating divisions within the working class are important problems, but that many of these may be overcome through appropriate interventions.

Health Maintenance Organizations↗
PubMed1991

Production and characterization of monoclonal antibodies against carcinoembryonic antigen (CEA).

In the experiments presented here 22 monoclonal antibodies (MoAbs) were produced which reacted with the tumor marker carcinoembryonic antigen (CEA). Eleven of the MoAbs reacted neither with peripheral blood granulocytes nor with purified spleen NCA-60 kDa and were therefore regarded as "CEA-specific". Only three antibodies of this group reacted exclusively with CEA-180 kDa. Eight MoAbs reacted with CEA-180 kDa and with CEA-like substances of lower molecular mass (of 160 kDa and/or 120 kDa) present in colon carcinoma cells as determined by immunoblotting. These molecules seem to be different from the classical non-specific cross-reacting antigens (NCAs) present in peripheral blood granulocytes. In contrast to that, the other 11 anti-CEA MoAbs recognized in addition to CEA-180 kDa also NCAs on granulocytes. Six of them were reactive with a purified spleen NCA-60 kDa preparation. These MoAbs bound also to reduced and alkylated CEA-180 kDa (CEA r/a), i.e. they recognize sequential epitopes. All 22 MoAbs reacted with CEA expressed in different human tumor cell lines as determined by immunocytological analysis. But six of them did not bind to the surface of these cells when tested in a radioimmuno-binding assay. It was concluded that the epitope(s) recognized by these antibodies are involved in cell membrane anchoring of the CEA-molecules.

Antibodies, Monoclonal↗