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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 865 records · Page 48Linked to original sources
PubMed1991

T-cell clones identify three distinct epitopes associated with HLA-Dw14.

Alloreactive T-cell clones were used to study allodeterminants associated with the HLA-DR1, -DR4, and -DRw14 allelic families. Three clones derived by priming against the DR4,Dw14 alloantigen were tested against a panel of HLA-D homozygous B-cell lines and homozygous and heterozygous peripheral blood lymphocytes. Each clone was blocked by monoclonal antibodies specific for HLA-DR, but not HLA-DQ or -DP, molecules, and each showed a unique pattern of allorecognition when tested against the cell panel. Clone 14B appeared to recognize a specific sequence, termed L67-A74, comprised of amino acids in the third hypervariable region of the alpha-helix of the DR beta 1 molecule, and expressed on certain DR1-, DR4-, and DRw14-positive cells. Clone EMO25 recognized the same L67-A74 sequence, but only when expressed on DR4-positive cells, suggesting a role for residues in the first and second hypervariable regions of DR4-positive DR beta 1 molecules in T-cell recognition. Clone EM036 also recognized the L67-A74 sequence, but only when expressed on DR4,Dw14.1-positive cells, implicating residues at positions 57 and 86 of the alpha-helix in T-cell recognition. These results demonstrate the range of specific T-cell responses that are possible against alloepitopes expressed by a single class II allele (Dw14), and are an indication of the diverse regions of the class II molecule that can contribute to allorecognition sites.

Amino Acid Sequence↗
PubMed1991

Using critical learning incidents in nurse education.

This paper describes an attempt to provide a learning environment conducive to the development of conceptual skills in critical exploration and problem solving. This is achieved by using a method of reflecting on and about critical incidents encountered by student nurses during their nursing practice. It is argued that students need help in making links between theory and practice and the article relates how this may be achieved in workshops using mainly experiential techniques. The authors conclude that the use of such a strategy can make a valuable contribution to nurse education, enabling students to look at situations from multiple perspectives and heightening awareness of the complex skills involved in nursing.

Clinical Competence↗
PubMed1991

Comparative pathology of breast cancer in a randomised trial of screening.

In the Edinburgh Randomised Breast Screening Project (EBSP) to December 1988 there were 500 cancers in the study population invited to screening and 340 cancers identified in the control population. The size and negative lymph node status characteristics of invasive cancers from the two populations were significantly different (P less than 0.05). The cancers detected by screening were predominantly 'early stage', with 16% noninvasive (PTIS) and 42% invasive stage I (pT1 node negative), whereas cancers were frequently 'late stage' (more than pT2) and inoperable in nonattenders (44%) and controls (36%). Grouped according to customary size ranges of invasive cancers, the proportion of cases lymph node positive differed in those screen detected compared with controls, but the benefit in favour of screen detection was not constant. In comparisons of cancers detected at prevalence and incidence screens, as a test of conformity with screening theory, no significant differences were apparent according to size and lymph node status, yet the characteristics of histological type of cancer discriminated significantly (P less than 0.05). When these same histological characteristics were used to compare survival, the capacity to separate invasive cancers into two groups having good and poor survival probabilities was evident, with a significant improvement for the screen detected poor survival group compared with controls (P less than 0.05).

Breast Neoplasms↗
PubMed1991

Selective immunotherapy of small cell cancer xenografts using 131I-labelled SWA11 antibody.

Intact SWA11 antibody was evaluated as a potential radioimmunotherapeutic agent against small cell lung cancer xenografts in a nude mouse model system. 131I-labelled SWA11 was given either in a single injection regimen (1 x 300 microCi) or as a multiple injection regimen achieving a total of 900 microCi (3 x 300 microCi with a 2 week interval between injections). Treatment of both small (mean volume approximately 0.2 cm3) and large (mean volume approximately 1.0 cm3) established xenografts resulted in significant anti-tumour effects and, in the case of the fractionated protocol, the failure of the xenografts to regrow within the period of observation (84 days). Xenograft histology following radioimmunotherapy showed large areas of necrosis, fibrosis and very few residual cells of SCLC origin.

Animals↗
PubMed1991

A clinically applicable method for long-term salvage of postischemic skeletal muscle.

The clinical significance and applicability of interventions aimed at reducing reperfusion injury in postischemic skeletal muscle remain unproven, since long-term muscle salvage has not been demonstrated by most treatment protocols that attenuate early reperfusion injury. We have shown that reperfusion of ischemic skeletal muscle results in an early and prolonged sequestration of white blood cells and activation of the alternative complement cascade. The purpose of this study was to determine if 40 minutes of reperfusion with blood depleted of white blood cells and complement proteins, followed by 2 days of normal perfusion, would reduce muscle necrosis after 5 hours of ischemia. The isolated paired canine gracilis muscle model was used. The treatment muscle was initially reperfused with arterial blood that had been spun, washed, passed through a leukocyte removal filter, and resuspended in hydroxyethyl starch (greater than 99.9% removal of white blood cells and the complement proteins factor B and C4). The contralateral control muscle was subjected to unaltered reperfusion. Blood flow (ml/min/100 gm) was measured by timed collection of gracilis venous blood. Myeloperoxidase activity (absorbance at 655 nm/min/mg tissue protein) in muscle biopsies was used to monitor white blood cell sequestration. After 48 hours of reperfusion in vivo, necrosis was quantified by nitroblue tetrazolium staining. Initial reperfusion with white blood cell and complement depleted blood significantly reduced muscle necrosis (53% +/- 3% vs 29% +/- 8%, p less than 0.0025, paired t test). Early blood flow was improved, (p = 0.0025, repeated measure-ANOVA), but subsequent white blood cell sequestration was not altered (p = 0.33, repeated measure-ANOVA). This suggests that a significant amount of white blood cell mediated injury occurs during the first 40 minutes of reperfusion. Preventing early complement activation and white blood cell mediated reperfusion injury is an intervention that is feasible during surgery and may result in clinically significant salvage of postischemic skeletal muscle.

Animals↗
PubMed1991

Clinical nursing research priorities: a Delphi study.

Using the delphi technique, a group of clinical nurse specialists was surveyed regarding delineation of clinical nursing research priorities. Upon completion of the four-round survey, the results suggested that the top priorities for nursing research are: (1) factors which influence longevity in clinical nursing practice, (2) patient care delivery systems as related to nurse satisfaction, and (3) indicators of quality nursing care.

Attitude of Health Personnel↗
PubMed1991

Renin and atrial natriuretic peptide restriction fragment length polymorphisms: association with ethnicity and blood pressure.

An investigation of restriction fragment length polymorphisms (RFLPs) and association with blood pressure was carried out for the candidate genes coding for renin (REN) and atrial natriuretic peptide (ANP). The relationship between blood pressure, REN and ANP gene RFLPs was tested in a population of black Afro-Caribbean and white European subjects sampled randomly from family practice registers. Upper and lower quintiles for diastolic blood pressure were selected for analysis. Digests of DNA were prepared from leucocytes and RFLPs were determined using Southern blotting analysis with REN and ANP gene probes. There were highly significant ethnic differences found for BglI, Bg/lI and TaqI polymorphisms with 5'REN probe and for BglI polymorphism with an ANP probe. There was also an association between blood pressure and the BglI/REN polymorphism in Afro-Caribbeans but not with any other polymorphisms studied in either ethnic group. The findings show significant ethnic RFLP differences at the gene loci for both renin and ANP and provide evidence for a possible link between variations within or close to the renin gene and elevated blood pressure in Afro-Caribbeans.

Aged↗
PubMed1991

Molecular and cytogenetic studies of the Prader-Willi syndrome.

Twenty-seven subjects with the Prader-Willi syndrome (PWS) were studied. Sixteen (59%) had a cytogenetic deletion involving chromosome 15q11-13. Nine were non-deletional and two patients had structural rearrangements of chromosome 15: 47,XY, + del(15)(pter----q12), var(15)(p11) and 45,XX,t(14q15q). At the DNA level, a greater proportion of patients (74%) showed loss of one chromosome 15q11-13 allele using a combination of densitometry and RFLP analysis. Deletion sizes were variable with 13 of 20 detectable both cytogenetically and with probe pML34 (D15S9). The remaining seven had microdeletions at the pML34 locus. Heterogeneity was further seen in three subjects who had cytogenetic deletions but normal DNA studies. In one patient there was evidence of a duplication at the pML34 locus. A new molecular rearrangement was identified with probe p3.21 (D15S10) in two patients and their mothers. Fifteen family studies were performed. In all 10 families where there was a molecular deletion, this was shown to have arisen de novo. DNA mapping confirmed that the paternal 15q allele was lost in three patients with PWS.

Adolescent↗
PubMed1991

Depressed contractile function due to canine mitral regurgitation improves after correction of the volume overload.

It is known that long-standing volume overload on the left ventricle due to mitral regurgitation eventually leads to contractile dysfunction. However, it is unknown whether or not correction of the volume overload can lead to recovery of contractility. In this study we tested the hypothesis that depressed contractile function due to volume overload in mitral regurgitation could return toward normal after mitral valve replacement. Using a canine model of mitral regurgitation which is known to produce contractile dysfunction, we examined contractile function longitudinally in seven dogs at baseline, after 3 mo of mitral regurgitation, 1 mo after mitral valve replacement, and 3 mo after mitral valve replacement. After 3 mo of mitral regurgitation (regurgitant fraction 0.62 +/- 0.04), end-diastolic volume had nearly doubled from 68 +/- 6.8 to 123 +/- 12.1 ml (P less than 0.05). All five indices of contractile function which we examined were depressed. For instance, maximum fiber elastance (EmaxF) obtained by assessment of time-varying elastance decreased from 5.95 +/- 0.71 to 2.25 +/- 0.18 (P less than 0.05). The end-systolic stiffness constant (k) was also depressed from 4.2 +/- 0.4 to 2.1 +/- 0.3. 3 mo after mitral valve replacement all indexes of contractile function had returned to or toward normal (e.g., EmaxF 3.65 +/- 0.21 and k 4.2 +/- 0.3). We conclude that previously depressed contractile function due to volume overload can improve after correction of the overload.

Animals↗
PubMed1991

Detection of CAIII mRNA in rat skeletal muscle and liver by in situ hybridization.

We carried out a variety of in situ methods of hybridization on rat liver and rat skeletal muscle using 35S-labeled or biotin-labeled rat carbonic anhydrase III (CAIII) cDNA clone. The methods were compared and evaluated. Use of the biotin system produced defined but nonspecific results which were shown not to be due to the biotinylated cDNA probe binding to the mRNA in the muscle sections. This artifact was shown to persist despite various attempts to eliminate it. Alternatively, using 35S-labeled cDNA gave reproducible results which were shown to be consistent with probe binding specifically to mRNA in the muscle section.

Adenosine Triphosphatases↗
PubMed1991

Comprehensive assessment of families of the critically ill.

The family enters the critical care unit under a significant amount of stress with many diverse and complex needs. During this crisis period, dysfunctional behavior may lead to ineffective coping. This article will present a comprehensive family assessment tool based on Myra Levine's Principles of Conservation. The assessment tool not only will enhance the comprehensiveness of patient and family care, but will provide a method for reassuring families that they are part of their relatives' care and recovery. This tool will also enable the critical care nurse to individually assess and meet the holistic needs of families.

Adaptation, Psychological↗