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Biomedical subjects

S Bryant

Publications and source records attributed to S Bryant.

At least 55 records · Page 3Linked to original sources
PubMed1992

Graduate home health education: a survey of home health educators and agency personnel.

To determine if there is a body of essential content that should be common to master's-level home care programs, a purposive sample of 200 nurses involved in home health or community health nursing was selected. The respondents (N = 118), including faculty and educational administrators (N = 61) and supervisors and administrators of home health agencies (N = 57), were asked their perceptions of the knowledge needed and their priorities for curriculum content for master's-prepared home care specialists in both clinical and administrative roles. There was agreement in most content areas, but significant differences were found between faculty and agency personnel in their priorities for community health concepts, and in their evaluation of nursing theory and epidemiology as essential content in both roles. We believe these results have important implications for nurse educators. As schools prepare students for leadership roles in today's home care environment, it is critical that pertinent content be well integrated into the curriculum.

Community Health Nursing↗
PubMed1991

The trkB tyrosine protein kinase is a receptor for brain-derived neurotrophic factor and neurotrophin-3.

trkB is a tyrosine protein kinase gene highly related to trk, a proto-oncogene that encodes a receptor for nerve growth factor (NGF) and neurotrophin-3 (NT-3). trkB expression is confined to structures of the central and peripheral nervous systems, suggesting it also encodes a receptor for neurotrophic factors. Here we show that brain-derived neurotrophic factor (BDNF) and NT-3, but not NGF, can induce rapid phosphorylation on tyrosine of gp145trkB, one of the receptors encoded by trkB. BDNF and NT-3 can induce DNA synthesis in quiescent NIH 3T3 cells that express gp145trkB. Cotransfection of plasmids encoding gp145trkB and BDNF or NT-3 leads to transformation of recipient NIH 3T3 cells. In these assays, BDNF elicits a response at least two orders of magnitude higher than NT-3. Finally, 125I-NT-3 binds to NIH 3T3 cells expressing gp145trkB; binding can be competed by NT-3 and BDNF but not by NGF. These findings indicate that gp145trkB may function as a neurotrophic receptor for BDNF and NT-3.

Animals↗
PubMed1991

Mechanism of activation of the vav protooncogene.

vav is a human locus that appears to be specifically expressed in cells of hematopoietic origin regardless of their differentiation lineage. This gene was first identified as a result of its malignant activation during the course of gene transfer assays (Katzav, S., Martin-Zanca, D., and Barbacid, M. EMBO J., 8: 2283-2290, 1989). In this study, we report the isolation of complementary DNA clones containing the entire coding sequence of the mouse vav protooncogene. Antisera raised against a peptide corresponding to a predicted hydrophilic domain have allowed us to identify the product of the vav gene as a 95,000 Da protein. Analysis of the deduced amino acid sequence of p95vav revealed an amino-terminal leucine-rich region not present in the activated vav oncogene. This region consists of an amphipathic helix-loop-helix followed by a leucine zipper, a structure reminiscent of the carboxy-terminal region of myc proteins and the steroid binding domain of nuclear receptors. In vitro mutagenicity studies have indicated that removal of the amphipathic helix-loop-helix is sufficient to activate the transforming potential of human and mouse vav protooncogenes. vav proteins also possess a cysteine-rich domain whose sequence predicts the formation of two putative metal binding-like domains, Cys-X2-Cys-X13-Cys-X2-Cys and His-X2-Cys-X6-Cys-X2-His. Replacement of some of these cysteine and histidine residues completely abolished the transforming activity of vav genes. Further examination of the alignment of cysteine residues in this region revealed an alternative structure, Cys-X2-Cys-X13-Cys-X2-Cys-X7-Cys-X6-Cys, which is reminiscent of the phorbol ester binding domain of protein kinase C. A similar domain has been recently identified in a second enzyme, diacylglycerol kinase. These structural similarities, along with its expression pattern, suggest that the vav protooncogene codes for a new type of signal-transducing molecule that may play an important role in controlling hematopoiesis.

Amino Acid Sequence↗
PubMed1990

Prevalence of haemochromatosis amongst asymptomatic Australians.

We determined the prevalence of iron overload due to homozygous haemochromatosis in an asymptomatic Australian (predominantly Caucasian) population by surveying 1968 employees of two large corporations. Subjects were screened by measurement of transferrin saturation and serum ferritin concentration and, in all subjects with elevation of both indices, percutaneous liver biopsy was performed to establish whether significant iron overload was present. The prevalence of iron overload due to haemochromatosis in this population was 0.36%. The prevalence rate was not significantly different between males and females, suggesting that this autosomal recessive disease is expressed equally in females given an adequate dietary iron supply. The positive predictive value of a transferrin saturation consistently greater than 45% together with an elevated serum ferritin concentration was 64%. It is concluded that the prevalence of significant iron overload due to homozygous haemochromatosis warranting treatment is approximately 1:300 and that transferrin saturation should be included in existing adult health screening programmes.

Adolescent↗
PubMed1988

Detrimental haemodynamic effects of cyclizine in heart failure.

The haemodynamic effects of intravenous cyclizine, an antiemetic that is widely given with opioids in left ventricular failure and myocardial infarction, were studied in 11 patients with severe heart failure. Cyclizine significantly increased systemic and pulmonary arterial pressures, and right and left ventricular filling pressures, and negated the venodilatory effects of diamorphine. The use of cyclizine in patients with heart failure should, therefore, be avoided.

Adult↗
PubMed1987

Tensile bond strengths of orthodontic bonding resins and attachments to etched enamel.

The purpose of this in vitro study was to determine the tensile bond strengths (TBS) of several orthodontic bonding systems and orthodontic brackets to enamel surfaces exposed to different etching procedures. The TBS of four bonding systems were determined by a test method developed by Kemper and Kilian. Twelve test specimens were prepared for each procedure. The test system was modified to determine the TBS of orthodontic brackets bonded to enamel surfaces by six bonding procedures and the TBS were evaluated 15 minutes and 24 hours after specimen preparation. The specimens were loaded to failure in an Instron machine operated at a crosshead speed of 0.02 inch/min. The TBS were expressed in MN.m-2. The TBS of the four bonding systems to etched enamel were not significantly different (P = 0.2528). The TBS of bonded brackets determined 24 hours after specimen preparation were not significantly different than the TBS recorded after 15 minutes except for brackets bonded with Lee Cleanse and Bond I to enamel surfaces etched with 15% H3PO4 for 30 seconds. The TBS of brackets to enamel etched with 15% H3PO4 for 30 seconds were not significantly different from the TBS to enamel surfaces etched with 5% H3PO4 for 15 seconds except for brackets bonded with Lee Cleanse and Bond II and tested 24 hours after bonding.

Acid Etching, Dental↗
PubMed1986

Computer diagnosis in jaundice. Bayes' rule founded on 1002 consecutive cases.

Extensive clinical and clinical chemical information was collected from 1002 consecutive jaundiced patients. Initial selection of variables based on Chi 2-tests or Mann-Whitney U-test allowed the removal of 64 of the 107 variables originally collected. A further selection of variables was carried out using a modified version of Bayes' rule thus reducing the number of variables from 43 to 22. Of the 982 patients with a final diagnosis 743 patients (76%) could be classified correctly into one of 13 diagnostic categories. The Bayes' rule was also applied to a test group of a further 110 jaundiced patients and found to perform equally well: of 108 patients with a final diagnosis 81 (75%) were correctly classified. A comparison between the clinician's diagnosis and the computer-aided diagnosis according to Bayes' rule demonstrated agreement with regard to one of the 13 diagnostic alternatives in 734 patients (75%), of whom 81 patients were wrongly diagnosed. In the test group agreement upon diagnosis was found in 80 patients (74%). By plausibly combining the computer-aided and the clinician's preliminary diagnoses, more correct classifications were obtained than with either method alone. Many diagnostic modalities such as ultrasound examination, CT-scan, and direct cholangiography are at hand today for the differential diagnosis of jaundice. Computer-aided diagnosis using Bayes' rule has proved a reliable tool for the clinician and can be used in the planning of a diagnostic strategy for the individual jaundiced patient.

Adolescent↗
PubMed1986

Genetic-environmental interactions in chronic airways obstruction.

To examine patterns of interaction between cigarette smoking and genetic factors in relation to airways obstruction, cross sectional data were analysed on 1787 white non-patient adult participants in a genetic-epidemiological study of airways obstruction (AO), defined as one-second forced expiratory volume FEV1 less than 68% of forced vital capacity FVC. Interaction was examined between smoking and each of four factors previously found to be related to AO: alpha-1 antitrypsin (PiZ allele), ABO blood groups (A antigen), ABH non-secretor status, and first degree relationship to a COPD or lung cancer patient. Multiple linear regression was used to test for interaction and adjust mean FEV1 (as a per cent of FVC) and prevalence of AO for age, sex, socioeconomic status, coffee and alcohol intake. Statistical interaction was observed between smoking (measured in pack-years) and two genetic factors (presence of blood A antigen and the family history). At higher pack-year levels, those individuals with the A antigen or the family history, but especially those with both factors had a much lower mean FEV1/FVC % and a much higher prevalence of AO than expected based on a simple additive model. On the other hand, there was no interaction between smoking and PiZ allele, or smoking and ABH secretor status. The findings suggest a possible biological interaction between cigarette smoke and the airways of individuals with blood group A antigen and familial lung disease. The findings also emphasize the role of genetic-environmental interactions in chronic diseases of multifactorial aetiology.

ABO Blood-Group System↗
PubMed1985

The effect of topical fluoride treatment on enamel fluoride uptake and the tensile bond strength of an orthodontic bonding resin.

Enamel demineralization occurring adjacent to directly bonded orthodontic attachments is of great concern to orthodontists. The topical application of fluorides to enamel surfaces before acid etching and the bonding of the attachments is not recommended by many investigators. The objective of this study was to determine the enamel fluoride acquired from various topical fluoride agents and to determine the effect of the acquired fluoride on the tensile bond strength of an orthodontic bonding system. Fifty extracted maxillary central incisors were mounted in cups and the facial surfaces of the crowns were polished on 600-grit silicon carbide paper. Enamel microbiopsies were performed just off the midpoint of each tooth. Ten teeth served as controls and received no topical fluoride treatment, while a similar number were treated with either APF, SnF2, Duraphat, or Fluor Protector. The teeth were suspended in synthetic saliva 4 minutes after fluoride application. The topical fluoride agents were removed after 24 hours and the teeth were again suspended in synthetic saliva at 37 degrees C for 7 days. Enamel biopsies were again performed just off the midpoint of each tooth on the side not previously biopsied. The enamel surfaces were etched for 1 minute and the tensile bond strength of Concise orthodontic bonding system to the etched enamel surfaces was determined. The enamel surfaces acquired significantly different amounts of fluoride from the topical fluoride agents, but the bond strengths to these surfaces were not significantly different. The results of this in vitro study suggest that the application of topical fluoride agents to enamel surfaces 7 days before the bonding of orthodontic attachments will not have an adverse effect on bond strength.

Acid Etching, Dental↗
PubMed1984

Labeling suspended aerosol particles with short-lived radionuclides for determination of particle deposition.

Radiotracer techniques were developed to examine parameters that characterize pressurized aerosols designed to deliver insoluble particles suspended in the aerosol formulation. Microaggregated bovine serum albumin microspheres that were to be suspended were labeled with iodine-131 (t1/2 = 8 d). This iodination procedure (greater than 80% effective) is also applicable to iodine-123, which possesses superior characteristics for external imaging and further in vivo studies. This report shows that for pressurized aerosols containing suspended particles, each metered dose is approximately equal (not including the priming doses and the emptying doses). Increase in the delivery of the albumin particles out of the canister was best achieved by pretreating the valve assembly with a solution of 2% (w/v) bovine serum albumin in phosphate buffer. Use of a cascade impactor delineated the particle size distribution of the micropheres, with the majority of particles ranging in size from 2 to 8 microns. The data disclosed here indicate that the techniques developed with short-lived radionuclides can be used to quantitate each metered dose, characterize the particle size distribution profile of the aerosol contents, and determine the extent of deposition of the particles in the aerosol canister and all of its components.

Aerosols↗
PubMed1983

The dexamethasone suppression test as a predictor of antidepressant response.

There is some evidence to suggest that dexamethasone suppression test (DST) results obtained prior to treatment for depression might aid in selecting the proper type of antidepressant medication. Forty endogenously depressed outpatients were evaluated with the DST and 12 (30%) were identified as nonsuppressors. All patients were then treated with desipramine (150-350 mg/day). Plasma concentrations of desipramine were monitored to assure that therapeutic levels were achieved. At 5 weeks of treatment, patients were characterized as treatment responders or nonresponders on the basis of change in Hamilton Depression Scale scores.

Adolescent↗