Biomedical subjects
Publications and source records attributed to N Fraser.
We report a child who sustained a traumatic hernia of the lower abdominal wall after being thrown forward against the handlebar of his bicycle. This is a rare injury in children, and the clinical features mimic an inguinal haematoma. Suspicion should be raised by the immediate appearance of a mass above the inguinal canal following groin injury, particularly if the swelling then disappears with the patient supine.
One- and two-dimensional solid-state NMR experiments on a uniformly labeled intrinsic membrane-protein complex at ultra-high magnetic fields are presented. Two-dimensional backbone and side-chain correlations for a [U-13C, 15N] labeled version of the LH2 light-harvesting complex indicate significant resolution at low temperatures and under Magic Angle Spinning. Tentative assignments of some of the observed correlations are presented and attributed to the alpha-helical segments of the protein, mostly found in the membrane interior.
We report the first clinical evidence that probiotic lactobacilli can be delivered to the vagina following oral intake. In 10 women with a history of recurrent yeast vaginitis, bacterial vaginosis (BV) and urinary tract infections, strains Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 suspended in skim milk and given twice daily for 14 days, were recovered from the vagina and identified by morphology and molecular typing within 1 week of commencement of therapy. In six cases of asymptomatic BV or intermediate BV (based upon Nugent scoring) was resolved within 1 week of therapy.
Agonist activity at G protein-coupled receptors (GPCRs) that regulate heterotrimeric G proteins of the Galpha(i/o) or Galpha(q) families has been shown to result in activation of the mitogen-activated protein (MAP) kinase cascade. To facilitate compound screening for these classes of GPCR, we have developed a reporter gene that detects the activation of the ternary complex transcription factor Sap1a following MAP kinase activation. In contrast to other reporter gene assays for Galpha(i/o)-coupled GPCRs, the MAP kinase reporter generates an increase in signal in the presence of agonist. The reporter gene has been transfected into Chinese hamster ovary cells to generate a "host" reporter gene-containing cell line. The Galpha(i)-coupled human CXCR1 chemokine receptor was subsequently transfected into this cell line in order to develop a 384-well format screen for both agonists and antagonists of this receptor. Agonists activated the reporter gene with the expected rank order of potency and with similar concentration dependence as seen with the regulation of other signal transduction cascades in mammalian cells: interleukin-8 (IL-8) (pEC(50) = 7.0 +/- 0.1) > GCP-2 (pEC(50) = 6.3 +/- 0.1) > NAP-2 (pEC(50) < 6). CXCR1-mediated activation of MAP kinase was inhibited by pertussis toxin and the MEK inhibitor PD98059, demonstrating that receptor activation of MAP kinase is due to pertussis toxin-sensitive Galpha(i/o)-family G proteins to cause the activation of MEK kinase. Using the 384-well format, assay performance was unaffected by solvent concentrations of 0.5% ethanol, 0.15% glycerol, or 1% DMSO. Signal crosstalk between adjacent wells was less than 1%. The assay exhibited a Z factor of 0.53 and a coefficient of variation of response to repeated application of IL-8 (100 nM) of 15.9%.
We have pharmacologically characterized recombinant human mt(1) and MT(2) receptors, stably expressed in Chinese hamster ovary cells (CHO-mt(1) and CHO-MT(2)), by measurement of [(3)H]-melatonin binding and forskolin-stimulated cyclic AMP (cAMP) production. [3H]-melatonin bound to mt(1) and MT(2) receptors with pK(D) values of 9.89 and 9.56 and B(max) values of 1.20 and 0.82 pmol mg(-1) protein, respectively. Whilst most melatonin receptor agonists had similar affinities for mt(1) and MT(2) receptors, a number of putative antagonists had substantially higher affinities for MT(2) receptors, including luzindole (11 fold), GR128107 (23 fold) and 4-P-PDOT (61 fold). In both CHO-mt(1) and CHO-MT(2) cells, melatonin inhibited forskolin-stimulated accumulation of cyclic AMP in a concentration-dependent manner (pIC(50) 9.53 and 9.74, respectively) causing 83 and 64% inhibition of cyclic AMP production at 100 nM, respectively. The potencies of a range of melatonin receptor agonists were determined. At MT(2) receptors, melatonin, 2-iodomelatonin and 6-chloromelatonin were essentially equipotent, whilst at the mt(1) receptor these agonists gave the rank order of potency of 2-iodomelatonin>melatonin>6-chloromelatonin. In both CHO-mt(1) and CHO-MT(2) cells, melatonin-induced inhibition of forskolin-stimulated cyclic AMP production was antagonized in a concentration-dependent manner by the melatonin receptor antagonist luzindole, with pA(2) values of 5.75 and 7.64, respectively. Melatonin-mediated responses were abolished by pre-treatment of cells with pertussis toxin, consistent with activation of G(i)/G(o) G-proteins. This is the first report of the use of [(3)H]-melatonin for the characterization of recombinant mt(1) and MT(2) receptors. Our results demonstrate that these receptor subtypes have distinct pharmacological profiles.
We enjoyed a very low level of DNBI during our deployment and no soldier had to be returned to the UK on medical grounds. None of the measures employed to reduce disease were complicated or new and most were merely common sense. The implementation does however require firm conviction by the chain of command. As in virtually all conflicts the greatest threat to a deployed force continues to be disease.
OBJECTIVES: This article seeks to review debates about age-based rationing in health care. METHODS: The article identifies four different levels (or types) of decision-making in health resources allocation--societal, strategic, programmatic, and clinical--and assesses how the issues of rationing vary in relation to each level. RESULTS: The article concludes that rationing is least defensible at the clinical level, where it is also most covert. The role of rationing at other levels is more defensible when based on grounds of cost-effectiveness rather than equity. The article emphasizes the importance of fairness in health allocation and suggests that efficiency criteria need to be considered in that context. DISCUSSION: The article suggests that rationing is most problematic where it is least overt. This raises further questions about how rationing can be made more explicit at different levels of decision making.
The GABA(B) receptor has been shown to consist of a heterodimer of two related 7-transmembrane receptors GABAB-R1 and GABA(B)-R2. These receptors share close homology to the Ca2+-sensing receptor and also to the metabotropic glutamate receptors, which have also been shown to respond to extracellular calcium. We show here that the GABA(B) receptor also has Ca2+ sensing properties. Ca2+ (0.001-1 mM) potentiated the GABA stimulation of [35S]GTPgammaS binding in membranes prepared from CHO cells stably expressing the GABA(B)-R1/R2 heterodimer. The GABA EC50 was reduced from 72 to 7.7 microM by addition of 1 mM Ca2+, with no change in the maximum response. A similar effect was observed in membranes from rat brain cortex. Ca2+ also potentiated GABA inhibition of forskolin-stimulated cAMP levels in the CHO cells and enhanced coupling to GIRK K+ channels in Xenopus oocytes. Other divalent cations were ineffective. The effects of Ca2+ were found to be agonist dependent with baclofen having a reduced sensitivity compared to GABA. Calcium appears to act allosterically to enhance GABA responses at the GABA(B) receptor, however, unlike the Ca2+-sensing receptor and some of the mGluR family, Ca2+ does not act as a ligand in its own right.
BACKGROUND: rhIGF-I has been used effectively to promote growth in growth hormone insensitivity syndrome (GHIS) in doses ranging from 40 microg/kg twice daily to 150-200 microg/kg once daily. It appears that the dose of 80 microg/kg twice daily s.c. may induce an equivalent response to higher doses with less side-effects. OBJECTIVE: To study the efficacy and safety of rhIGF-I, 80 microg/kg twice daily s.c., in children with GHIS and to analyse the relationship of growth response to severity of phenotype. PATIENTS AND DESIGN: Eleven prepubertal children (3 females, 8 males) with GHIS; basal GH > 2.5 microg/l, IGF-I < 50 microg/l, IGFBP-3 < - 2SD; were treated with IGF-I 80 microg/kg twice daily in a multi-centre study. The baseline characteristics of these patients were as follows (mean +/- SD): age, 7.5 +/- 2.5 years (range, 2.5-11.7 years), bone age (Tanner-Whitehouse - 2 RUS), 5.2 +/- 2.4 years (range, 2.3-9.1 years), mean height SDS, - 5.6 +/- 1.6 (range, - 3.1 to - 8.1), height velocity (HV), 3.1 +/- 1.1 cm/year (range, 1.9-4.9 cm/year). Height, HV, weight, skinfold thickness, puberty stage and bone age were measured at baseline and 6 monthly for 2 years. RESULTS: During the first 12 months of IGF-I therapy, the mean +/- SD HV was 7.7 +/- 1.6 cm/year (range, 6.1-11.2 cm/year), the mean +/- SD increase in HV was 4.7 +/- 2.1 cm/year (range, 1.7-8.8 cm/year) and the mean +/- SD progression of bone age was 1.9 +/- 1.0 years (range, 0.8-3.8 years). Pre-treatment height SDS at the start of IGF-I therapy correlated positively with pretreatment serum IGFBP-3 SDS levels (r = 0.85; P < 0.01). There was a significant inverse correlation between gain in height SDS and pre-treatment height SDS (r = - 0.76; P < 0.01). During the 2nd 12 months of therapy, mean HV was 7.0 +/- 3.4 cm/year (range 3.8-12.4) change in height SDS from 12 to 24 months was not significantly correlated with pre-treatment height SDS. Subscapular skinfold SDS decreased significantly (P < 0.05) during the study period, whereas there was no significant change in body mass index and triceps skinfold thickness SDS. Adverse events reported in the patient group included headache (2 patients), hypoglycaemia (2 patients), papilloedema (transient, 1 patient), lipohypertrophy (5 patients) and tonsillectomy/adenoidectomy (2 patients). CONCLUSION: This study reveals that IGF-I treatment at a dose of 80 microg/kg twice daily is effective in patients with growth hormone insensitivity syndrome. During the first 12 months of therapy, there was a significant inverse relationship between growth response to IGF-I therapy and the severity of the phenotype of growth hormone insensitivity syndrome, as measured by height SDS, at the start of therapy. Patients with a more severe clinical phenotype of growth hormone insensitivity syndrome, who also had most severe IGFBP-3 deficiency, responded better than those who were more mildly affected. An analogous situation has been shown to be the case in GH-deficient patients treated with hGH.
Transient expression of apoaequorin in Chinese hamster ovary (CHO) cells and reconstitution with the co-factor coelenterazine resulted in a large, concentration-dependent agonist-mediated luminescent response following cotransfection with the endothelin ETA, angiotensin ATII, thyrotropin-releasing hormone (TRH), and neurokinin NK1 receptors, all of which interact pre-dominantly with the G alpha q-like phosphoinositidase-linked G-proteins. A substantially greater luminescence was obtained with mitochondrially targeted apoaequorin compared to cytoplasmically expressed apoaequorin. To generate a system amenable for the study of agonist activity at virtually any G-protein-coupled receptor the alpha subunit of the receptor promiscuous G-protein G alpha 16 was either transiently or stably expressed in CHO cells together with apoaequorin. In cells expressing G alpha 16, but not in its absence, agonists at a series of receptors which normally interact with either G alpha s or G alpha i were now able to cause a luminescent response from mitochondrially targeted apoaequorin. In the case of the A1 adenosine receptor, this response was clearly a result of activation of G alpha 16 and not a consequence of the release of the G alpha i-associated beta/gamma complex, as the luminescent response was unaffected by pertussis toxin treatment of the cells, whereas agonist-mediated inhibition of adenylyl cyclase activity was attenuated. These studies describe the use of coexpressed apoaequorin as a reporter for G-protein-coupled receptor-mediated calcium signaling. Furthermore, coexpression of G alpha 16 and apoaequorin provides a basis for a generic mammalian cell microplate assay for the assessment of agonist action at virtually any G-protein-coupled receptor, including orphan receptors for which the physiological signal transduction mechanism may be unknown.
This report describes the experience gained in the last 8 years of implementing and administering a Quality Assurance Scheme dedicated to improving the reliability of Kleihauer test results in Scotland. Initially the five transfusion centres in Scotland were the only participants, but since 1992 all 15 hospital laboratories in Scotland performing the Kleihauer test to ensure an adequate dose of anti-D is administered to Rh-negative women, at risk of developing allo anti-D, have joined this voluntary scheme. As a result of the standardization of technical methods, improvement in reporting of QA results has been observed since 1994.
Explore the source record for details and available documents.
The purpose of this study was to investigate the induction of inducible nitric oxide synthase (iNOS) mRNA in the brain tissue of rats and mice under the following experimental conditions: in rats infected with borna disease virus and rabies virus, in mice infected with herpes simplex virus, and in rats after the induction of experimental allergic encephalitis. The results showed that iNOS mRNA, normally nondetectable in the brain, was present in animals after viral infection or after induction of experimental allergic encephalitis. The induction of iNOS mRNA coincided with the severity of clinical signs and in some cases with the presence of inflammatory cells in the brain. The results indicate that nitric oxide produced by cells induced by iNOS may be the toxic factor accounting for cell damage and this may open the door to approaches to the study of the pathogenesis of neurological diseases.
MK is a gene encoding a secreted heparin-binding polypeptide originally isolated by differential screening for genes induced by retinoic acid (RA) in HM-1 embryonal carcinoma cells. Here we report that MK is expressed at high levels in both embryonal carcinoma and pluripotential embryonic stem cells and their differentiated derivatives. MK expression in these cell types is unaffected by the presence or absence of RA. Recombinant MK protein (rMK) was produced by transient expression in COS cells and purified by heparin affinity chromatography. rMK is a weak mitogen for 10T1/2 fibroblast cells but inactive as a mitogen for Swiss 3T3 fibroblasts. rMK is a potent mitogen for neurectodermal precursor cell types generated by treatment of 1009 EC cells with RA but has no mitogenic or neurotrophic effects on more mature 1009-derived neuronal cell types. rMK is active as an in vitro neurotrophic factor for E12 chick sympathetic neurons and its activity is markedly potentiated by binding the factor to tissue-culture plastic in the presence of heparin. Stable 10T1/2 cells lines have been established which express MK. These cells do not exhibit any overt evidence of cell transformation but extracellular matrix preparations derived from these cells are a potent source of MK biological activity. It is concluded that MK is a multifunctional neuroregulatory molecule whose biological activity depends upon association with components of the extracellular matrix.
Explore the source record for details and available documents.
Bacillus Calmette-Guérin (BCG) vaccination against tuberculosis has been used around the world for 60 years, yet its efficacy in large, controlled prospective studies is inconsistent. The factors influencing BCG protection include variation in immunogenic potential, background exposure to environmental mycobacteria, and differences in host response to vaccine. As a means of addressing regional differences in protection, case-control studies provide a relatively inexpensive, rapid means of assessing regional vaccine effects. Treaty Indian cases (n = 160) resident in Alberta, Canada, presenting during a 5-year period (1975-1979) were individually matched for age, sex, and Band with two nontuberculous controls. A 57 percent protection by BCG vaccination was demonstrated. These results support the usefulness of case-control studies and their importance in planning tuberculosis control programs.
Explore the source record for details and available documents.
Several DNA sequences from two homologous regions, localized on the distal part of the human X chromosome short arm and on the long arm of the Y chromosome, have been hybridized to DNAs from seven human-rodent hybrids containing human X; Y translocation chromosomes. Molecular characterization of the translocated chromosomes has revealed, in all but one case, transfer of the Y cluster of sequences and complete deletion of the corresponding X-chromosomal sequences. The possible role of X/Y homology in the aetiology of X; Y translocations is proposed.