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Biomedical subjects

S Harris

Publications and source records attributed to S Harris.

At least 163 records · Page 9Linked to original sources
PubMed1994

Comparison of broadband ultrasound attenuation to single X-ray absorptiometry measurements at the calcaneus in postmenopausal women.

Broadband ultrasound attenuation (BUA), a radiation-free and portable technology, may be useful in assessing bone density and fracture risk. In this study, we compared cross-sectional BUA measurements to the more established single energy X-ray absorptiometry measurements of bone mineral density (BMD) at the calcaneus in 259 healthy postmenopausal women, aged 45-76 years. Paired measurements with repositioning of the subject's dominant heel were made consecutively by each method. A coefficient of variation (CV) for each method was calculated for each individual from the paired scans. BUA and BMD of the heel were also compared with BMD of the lumbar spine and femoral neck, as measured by dual energy X-ray absorptiometry. BUA was significantly correlated with BMD at the calcaneus (r = 0.66, P < 0.01). Heel BUA was also correlated with lumbar spine BMD (r = 0.43, P < 0.01) and femoral neck BMD (r = 0.43, P < 0.01) but the correlations were lower than those between heel BMD and spine (r = 0.63, P < 0.01) or femoral neck BMD (r = 0.62, P < 0.01). The mean CV for heel BUA (3.60 +/- 3.50%) was significantly greater than that for heel BMD (1.06 +/- 0.99%, P < 0.01). The moderate correlation of calcaneal BUA and BMD, the lower correlations of BUA than heel BMD with both spine and hip BMD, and lower precision of BUA indicate BUA does not predict bone density as effectively as absorptiometry, the current standard methodology.

Absorptiometry, Photon↗
PubMed1994

Project WINS: integrating vocational services on mental health case management teams.

In an effort to expand employment opportunities available to psychiatric consumers, a research demonstration project was developed to incorporate vocational services into case management teams. Following psychiatric rehabilitation principles, Project WINS employs professionals as Vocational Specialists and consumers as Peer Support Specialists to work with clients and their case managers. This report describes the characteristics of clients eligible for WINS services, the implementation of the program, and the impact of WINS on clients and on the mental health and vocational systems. It also describes the challenges and barriers this innovative service is confronting.

Adult↗
PubMed1994

Prostaglandin E1 does not accelerate rTPA-induced thrombolysis in acute myocardial infarction.

Fifteen patients who arrived between 6 and 24 hours after the onset of acute myocardial infarction and who were found to have totally occluded coronary arteries, received aspirin, heparin, and tissue plasminogen activator given over 3 hours. Eight patients were randomly assigned to receive intravenous prostaglandin E1, 20 ng/kg/min for 6 hours, while seven patients received placebo infusion. Coronary arteriography begun immediately before the start of tissue plasminogen activator and repeated every 15 minutes revealed restoration of antegrade flow in two of eight (25%) patients treated with prostaglandin E1 and in two of seven (28%) patients receiving placebo. Pharmacologic sampling of tissue plasminogen activator levels were performed at baseline and 30, 45, 60, 75, 90, 135, 180, 190, 210, and 240 minutes afterwards for assessment of tissue plasminogen activator antigen. There was no difference in fibrinogen levels and no difference in tissue plasminogen activator antigen levels at these time periods. Clearance values of tissue plasminogen activator were calculated and were not different between the two groups. These data do not support the use of prostaglandin E1 for the acceleration of reperfusion in patients receiving tissue plasminogen activator for acute myocardial infarction.

Alprostadil↗
PubMed1994

Evidence against roles for pertussis toxin sensitive G proteins or diacylglycerol generation in insulin-like growth factor-1 stimulated DNA synthesis in MG-63 osteosarcoma cells.

A pertussis toxin-sensitive G protein has been reported to play a role in the mitogenic response to insulin-like growth factor-I (IGF-I) in mouse fibroblasts, and diacylglycerol generation has been shown to accompany growth stimulation by IGF-I of several cell lines. We have examined the roles of pertussis toxin sensitive G proteins and diacylglycerol generation in signaling by the insulin-like growth factor-I receptor in a cell line that is very responsive to IGF-I, the human osteosarcoma cell line, MG-63. Pertussis toxin failed to inhibit IGF-I induced [3H]-thymidine incorporation into DNA. Furthermore, the stable analog GTP gamma S had no effect on the binding of 125I-labelled IGF-I to MG-63 membrane preparations. Following addition of IGF-I to growth-arrested MG-63 cells there was no increase in diacylglycerol levels over 30 min. We conclude that the activated IGF-I receptor does not use pertussis toxin sensitive G proteins or diacylglycerol generation in a pathway leading to DNA synthesis in MG-63 cells.

Cell Membrane↗
PubMed1994

Persistence of Mycobacterium bovis in cattle.

Badgers represent a wildlife reservoir for bovine tuberculosis in Britain, which persists in the south west despite almost 20 years of badger control. The influence of landscape structure on patterns of badger urinatory behaviour may be one reason for the localized persistence of the disease in cattle within the region.

Animals↗
PubMed1994

Serum type I procollagen peptide: a non-invasive index of bone formation in patients on haemodialysis?

The value of serum procollagen peptide (PICP) as a non-invasive index of bone formation was studied in 18 patients established on haemodialysis. There was a significant correlation between PICP and serum alkaline phosphatase activity (ALP; r = 0.55, P < 0.05), and between PICP and osteocalcin (r = 0.53, P < 0.05). PICP also correlated significantly with histomorphometric indices of bone formation, particularly bone formation rates (BFR) as estimated by the tetracycline double-labelled technique (r = 0.74, P < 0.01), but not with those of bone resorption. There was a similar relationship between BFR and ALP. From the regression analyses, a normal BFR was associated with normal PICP values despite the absence of renal function, suggesting that the impact of renal function on serum concentrations of PICP may not be large. Seven patients had histochemical evidence for significant aluminum overload. In these patients the expected suppression in biochemical and histological indices of bone formation was associated with inappropriately raised PICP concentrations. The mechanism of this discrepancy is not clear, but caution is advocated in the interpretation of PICP in the presence of significant aluminium overload. Our findings otherwise suggest that PICP may be a useful non-invasive index of bone formation in patients on haemodialysis.

Adolescent↗
PubMed1994

Fine mapping of the Darier's disease locus on chromosome 12q.

Darier's disease (DD) is an autosomal dominant genodermatosis characterized by epidermal acantholysis and dyskeratosis. We have performed genetic linkage studies in 10 families with DD (34 affected) by analyzing 14 polymorphic microsatellite markers. Our results confirm recent reports mapping the DD gene to chromosome 12q23-q24.1. Haplotype analysis of recombinant chromosomes in our families, along with previously reported data, narrow the location of the DD gene to a 5 cM interval flanked by the loci D12S354 and D12S84/D12S105. This localization allowed exclusion of two known genes, PLA2A and PAH, as candidate loci for DD. Three other gene loci (PPP1C, PMCH, PMCA1), mapping in 12q21-q24, remain potential candidates.

Adolescent↗
PubMed1994

Enhanced activation of human T cell clones specific for virus-like particles expressing the HIV V3 loop in the presence of HIV V3 loop-specific polyclonal antibodies.

Recombinant virus-like particles (VLP), formed by the yeast Ty p1 protein, carrying the HIV gp120 V3 loop on their surface (V3-VLP) have been tested in vitro for immunogenicity and antigenicity by using VLP p1-specific human CD4+ T cell lines and clones. VLP-specific human T cell lines and clones were generated from normal individuals, indicating that VLP-specific precursor cells present in the peripheral lymphocyte pool can be induced to expand clonally upon antigen challenge in vitro, in the absence of previous immunization. It was also shown that V3-specific polyclonal antibodies enhance V3-VLP-induced activation of VLP-specific T cell clones. Antibody-dependent potentiation has been shown previously in other antigen systems, and it depends on enhanced uptake of complexed antigen by Fc receptor-positive antigen-presenting cells. Since in this case antigen is internalized by presenting cells as a complex, it can be inferred that a similar event of antibody-mediated antigen uptake can take place with V3-specific B cells, resulting in presentation by the B cells of T helper epitopes derived from processing of the VLP p1 moiety. This suggests that T helper cells specific for the carrier VLP p1 protein can be activated to provide help to V3-specific B cells in the presence of the appropriate antigen construct.

Amino Acid Sequence↗
PubMed1994

Spaceflight results in reduced mRNA levels for tissue-specific proteins in the musculoskeletal system.

The purpose of the present study in growing rats was to investigate the effects of short-term spaceflight on gene expression in bone and muscle and on cortical bone histomorphometry. Two experiments were carried out; Physiological Systems Experiments 1 and 2 were 4- and 10-day flights, respectively. Radial bone growth in the humerus was unchanged during the 4-day flight and decreased during the 10-day flight. Expression of mRNA for glyceraldehyde-3-phosphate dehydrogenase was unchanged in biceps, calvarial periosteum, and long-bone periosteum after spaceflight. Similarly, no changes in ribosomal RNA levels were observed in long-bone or calvarial periosteum after spaceflight. In contrast, spaceflight decreased steady-state mRNA levels for actin in muscle (4-day flight). Osteocalcin (both spaceflights) and the prepro-alpha 2[I] chain of type I precollagen (10-day flight) mRNA levels were decreased in long-bone and calvarial periosteum after spaceflight. These results indicate that the effects of spaceflight on the musculoskeletal system include decreased expression of some muscle- and bone-specific genes as well as decreased bone formation. Interestingly, detectable reductions in gene expression for bone matrix proteins preceded histological evidence for decreased bone formation.

Actins↗
PubMed1994

The endocrinology of gestation failure in foxes (Vulpes vulpes).

The endocrine basis of reproductive failure in red fox vixens was examined over two breeding seasons in a total of 11 animals. Weekly blood samples were assayed for progesterone, prolactin, LH and cortisol. Vaginal smears taken every 2 days over the oestrous period indicated that all vixens had mated. Vixens that successfully gave birth to a litter of cubs demonstrated significantly higher plasma progesterone and prolactin concentrations but significantly lower cortisol concentrations than did females that had ovulated, but then failed to whelp. There were no significant differences in plasma LH concentrations. These data suggest that reproductive losses could result from lowered plasma progesterone concentrations, possibly resulting from inadequate luteotrophic support by prolactin. A stress-induced mechanism of reproductive failure is implicated and is discussed in relation to social suppression of reproduction.

Abortion, Veterinary↗
PubMed1994

Maternal serum screening in the Sioux Lookout Zone. Complicated test for an unspecified need.

We investigated whether the incidence of fetal abnormalities among patients in Sioux Lookout Zone differs from incidence elsewhere in Canada, whether First Nations people would agree to screening, how information could be disseminated, and what practical considerations would affect implementation. Incidence appears to be similar to elsewhere, but First Nations people's cultural and spiritual beliefs and the difficulty of taking action once results are confirmed make current screening programs inappropriate.

Chorionic Gonadotropin↗
PubMed1994

Pharmacokinetics of desipramine coadministered with sertraline or fluoxetine.

The pharmacokinetic interactions of sertraline and fluoxetine with the tricyclic antidepressant desipramine were studied in 18 healthy male volunteers phenotyped as extensive metabolizers of dextromethorphan. Concentrations in plasma were determined after 7 days of desipramine (50 mg/day) dosing alone, during the 21 days of desipramine and selective serotonin reuptake inhibitor (SSRI) coadministration (fluoxetine, 20 mg/day; sertraline, 50 mg/day), and for 21 days of continued desipramine administration after SSRI discontinuation. Desipramine Cmax was increased 4.0-fold versus 31% and AUC0-24 was increased 4.8-fold versus 23% for fluoxetine versus sertraline, respectively, relative to baseline after 3 weeks of coadministration. Desipramine trough concentrations approached baseline within 1 week of sertraline discontinuation but remained elevated for the 3-week follow-up period after fluoxetine discontinuation. Concentrations of SSRIs and their metabolites correlated significantly with desipramine concentration changes (for fluoxetine/norfluoxetine, r = 0.94 to 0.96; p < 0.001; for sertraline/desmethylsertraline, r = 0.63; p < 0.01). Thus, sertraline had less pharmacokinetic interaction with desipramine than did fluoxetine at their respective, minimum, usually effective doses.

1-Naphthylamine↗
PubMed1993

Insulin-like growth factor-I (IGF-I) dependent phosphorylation of the IGF-I receptor in MG-63 cells.

Insulin-like growth factor I (IGF-I) stimulates multiplication of the human osteosarcoma cell line, MG-63. by acting through the IGF-I receptor. We have characterized IGF-I stimulated phosphorylation of the IGF-I receptor in this cell line. Serum starved MG-63 cells were metabolically labeled with [32P]orthophosphoric acid and the cells were treated with IGF-I. Phosphotyrosine containing proteins were immunoprecipitated from the cell lysates with antiphosphotyrosine-Agarose and eluted with phenyl phosphate. Further immunoprecipitation with IGF-I receptor monoclonal antibodies (alpha IR-3, 18E9) and analysis by sodium dodecylsulfate polyacrylamide gel electrophoresis and autoradiography demonstrated IGF-I dependent autophosphorylation of the IGF-I receptor. Phosphoamino acid analysis of the IGF-I receptor beta subunit and the observation that antiphosphotyrosine-Agarose did not immunoprecipitate [35S]methionine-labeled receptor from unstimulated cells, demonstrated that in the absence of IGF-I, the receptor was not phosphorylated on tyrosine residues. Western blotting of cell lysates with a monoclonal phosphotyrosine antibody did not identify the IGF-I receptor or pp185 but demonstrated IGF-I dependent phosphorylation on tyrosine residues in three other proteins, p110, p70 and p40.

Blotting, Western↗
PubMed1993

Badgers (Meles meles), cattle and bovine tuberculosis (Mycobacterium bovis): a hypothesis to explain the influence of habitat on the risk of disease transmission in southwest England.

Badgers are believed to be responsible for a high proportion of the cases of bovine tuberculosis in cattle in southwest England where, despite the onset of badger control operations in 1975, comparatively high numbers of cattle continue to fail the tuberculin test. To determine why the disease remains a problem in these areas, data on badger densities and patterns of land use were examined. Areas subject to repeated badger control operations had greater landscape heterogeneity and a higher density of linear habitat features. These habitat features were not related to badger density, measured as the mean number of social groups per square kilometre. Environmental contamination by infected badger urine is thought to be the main mode for the transmission of bovine tuberculosis. Field studies in an area with tuberculosis in both badgers and cattle showed that badgers may urinate on pasture after crossing through a linear feature, and that the number of these crossing-point urinations increases with the number of linear features crossed. The hypothesis is presented that these crossing-point urinations are a major source of bovine tuberculosis infection in cattle, and that areas with increased numbers of linear features have greater levels of contamination of pasture with badger urine and hence increased opportunities for disease transmission.

Animals↗
PubMed1993

A randomized study of outpatient treatment with ceftriaxone for selected febrile children with sickle cell disease.

BACKGROUND: Because of their susceptibility to pneumococcal sepsis, children with sickle cell disease and fever are usually hospitalized for antibiotic therapy. Outpatient treatment may be a safe and less expensive alternative for selected patients. METHODS: After evaluation in the emergency room, children ranging from 6 months to 12 years of age who had sickle hemoglobinopathies and temperatures exceeding 38.5 degrees C were randomly assigned to treatment as either inpatients or outpatients. We excluded from randomization children at higher risk of sepsis (as defined by specific criteria, including temperature above 40 degrees C, white-cell count below 5000 per cubic millimeter or above 30,000 per cubic millimeter, and the presence of pulmonary infiltrates) or with complications of sickle cell disease (such as a hemoglobin level below 5 g per deciliter, dehydration, or severe pain); these children were treated as inpatients. All patients received an initial intravenous dose of ceftriaxone (50 mg per kilogram of body weight). Those treated as outpatients returned 24 hours later for a second dose of ceftriaxone, whereas the in patients were treated as directed by their physicians. RESULTS: None of the 86 patients (with a total of 98 febrile episodes) in the randomized groups had sepsis, as compared with 6 of the 70 patients (7 of 86 episodes) excluded because of higher risk (P = 0.004). Among the 44 children (50 episodes) assigned to outpatient treatment, there were 11 hospitalizations (22 percent of episodes) within two weeks after treatment (95 percent confidence interval, 12 to 36 percent), whereas after inpatient care only a single patient (2 percent of episodes) was rehospitalized. When the randomized groups were compared, outpatient treatment saved a mean of $1,195 per febrile episode. The median hospital stay was 3 days (range, 1 to 6) for the children randomly assigned to inpatient care and 4 days (range, 1 to 18) for the higher-risk children treated as inpatients (P < 0.001). CONCLUSIONS: With the use of conservative eligibility criteria, at least half the febrile episodes in children with sickle cell disease can be treated safely on an outpatient basis, with substantial reductions in cost.

Ambulatory Care↗
PubMed1993

Scarborough Fair.

Stuart Harris and Jackie Morton describe a project which transformed a dilapidated council house in an underprivileged area of Scarborough into a multi-faceted health centre.

Community Health Centers↗