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Biomedical subjects

A Long

Publications and source records attributed to A Long.

At least 109 records · Page 6Linked to original sources
PubMed1995

Origin of sex for error repair. II. Rarity and extreme environments.

In a previous paper we studied the simultaneous, and at times conflicting, needs of coping with DNA damage, efficient cell replication, and the avoidance of cell mortality. These selective factors operated on sexual and asexual haploid and diploid populations that were reproductively isolated from one another. We concluded, in part, that a sexual type of cell could not expand from extreme rarity in populations dominated by asexual haploid and diploid cells. In the present paper we show that it is relatively easy for a rare sexual mutant to expand in a population dominated by asexual haploid cells if some matings occur between sexual and asexual cell types. We also study the persistence of sex in high mortality, high damage environments, in which neither the asexual diploid nor haploid can survive. The diploid cannot survive because its lower birth rate cannot overcome mortality and the haploid cannot survive because its birth rate cannot overcome gene damage. Sex can persist in these punishing environments by tuning the parameters of the sexual cycle, and the fusion and splitting rates, into a specified region, thereby reaping both benefits of damage repair and efficient replication.

Animals↗
PubMed1995

Long-term survival after intensive care unit admission with sepsis.

OBJECTIVE: To evaluate the long-term survival of critically ill patients with sepsis and to assess the factors predictive of long-term survival (> 1 month after admission date). DESIGN: Prospective, cohort study. SETTING: Medical/surgical intensive care unit (ICU) in a multidisciplinary community hospital. PATIENTS: All patients admitted to the ICU from January 1, 1987 to March 31, 1991 who both demonstrated clinical evidence of the systemic inflammatory response syndrome and yielded blood cultures positive for a bacterium or fungus (n = 153). INTERVENTIONS: Random set of procedures normally performed in an ICU setting. MEASUREMENTS AND MAIN RESULTS: Patient characteristics, including age, blood culture results, comorbid conditions, and severity of illness as estimated by the Acute Physiology Score of the Acute Physiology and Chronic Health Evaluation II prognostic system were recorded. Follow-up evaluation utilizing the National Death Index provided survival outcome for all patients 1 yr after hospital discharge. The mortality rate at hospital discharge was 51.0%, and mortality rates at 1 month, 6 months, and 1 yr after admission date were 40.5%, 64.7%, and 71.9%, respectively. A total of 33 patients survived beyond the period of observation. The analyses demonstrated the following findings: a) the survival rate was negatively correlated with the Acute Physiology Score up to 1 month after hospital admission date, but uncorrelated thereafter; b) fungal infections, such as Candida, had the shortest survival prospects of any blood-borne infection; and c) both malignancy and human immunodeficiency virus infection contributed to poorer outcomes, but differed in their patterns of long-term survival. CONCLUSIONS: The most critical period for surveillance of bacteremic patients was in months 2 through 6 after discharge, during which time, the percentage of patients surviving decreased dramatically. The degree of physiologic derangement, as measured by the Acute Physiology Score, was a useful measure of prognosis within the first month after the score was assessed at ICU admission. However, beyond this period, prognostic utility decreased significantly. Healthcare providers should use caution concerning the expected survival of hospitalized patients with human immunodeficiency virus, based on experience with distinct conditions, such as malignancies.

APACHE↗
PubMed1995

Suicide and parasuicide: a selected review of the literature.

The increase in adolescent suicides has prompted the World Health Organization to set targets to reduce the incidence of deaths by the year 2000. In order to achieve this target further investigation into the perceptions of adolescent parasuicidal individuals is required to reduce the number of suicide attempts. Statistical evidence shows that parasuicidal individuals are commonly females who attempt suicide by taking an overdose. In the majority of cases help has been sought within the month prior to the attempt. Following an attempt many individuals feel isolated or ignored by health professionals. It appears that communication difficulties and negative attitudes by health professionals often reinforce the stigma associated with suicide. Nurses can contribute to the prevention of parasuicide/suicide by actively providing therapeutic care and counselling parasuicidal individuals to help them deal with major life events.

Adolescent↗
PubMed1995

Supportive clinical supervision: a cruicible for personal and professional change.

The purpose of this paper is to explore theoretical and practical issues pertinent to the implementation and development of supportive clinical supervision. The paper highlights a facilitative model of supervision that emphasizes the importance of the supervisory relationship within a person-valuing ethos. The authors put a case for sensitive utilization of a supervision concept that leads, they conclude, to self development, self realization, professional enhancement and advancement, and high quality client care. Over time, the ultimate goals of such supervisory practice are twofold: (i) to improve the overall health of the nation and (ii) to promote the progression of the nursing profession. The authors found that a facilitative approach to clinical supervision is therapeutic and self-propelling for both supervisor and supervisee.

Clinical Competence↗
PubMed1995

Expression of CD44 on rheumatoid synovial fluid lymphocytes.

OBJECTIVES: To investigate the involvement of the adhesion molecule CD44 in the homing of lymphocytes to synovial tissue, by examining the density of expression and molecular mass of CD44 on rheumatoid synovial fluid lymphocytes. METHODS: Twenty patients with rheumatoid arthritis were studied. Peripheral blood and synovial fluid lymphocytes were isolated by Ficoll-Hypaque sedimentation. CD44 expression was analysed by two colour flow cytometry of CD3 positive T lymphocytes with calculation of mean fluorescence intensity. Expression of activation markers M21C5, M2B3, interleukin (IL)-2 receptor and transferrin receptor was quantitated. In addition, CD44 molecular mass was examined by Western blot in six patients. RESULTS: CD44 expression was markedly increased on synovial fluid T lymphocytes of rheumatoid patients relative to peripheral blood lymphocytes from the same individuals. CD44 molecular mass on peripheral blood mononuclear cells was 88 kDa, but that on synovial fluid lymphocytes was only 83 kDa. CD44 expression correlated significantly with expression of activation markers M21C5, M2B3, and the IL-2 receptor. CONCLUSIONS: Alterations in density of expression or of the molecular mass of CD44 could contribute to local tissue injury, either directly by facilitating adhesion, or indirectly through effects on other adhesion molecules.

Arthritis, Rheumatoid↗
PubMed1995

Tyrosine phosphorylation in the human duodenum.

Many growth factor receptors including the epidermal growth factor receptor function through tyrosine kinase activity. The aim of this study was to examine the constitutive level of tyrosine phosphorylation in the normal duodenum and in the hyperproliferative coeliac duodenum. A flow cytometric assay was devised using monoclonal antibody to phosphorylated (but not native) tyrosine residues to determine the levels of tyrosine phosphorylation in both CD3 positive intraepithelial lymphocytes and CD3 negative epithelial cells obtained by EDTA treatment of endoscopically obtained duodenal biopsy specimens. In addition, immunohistochemistry was performed on 18 formalin fixed coeliac duodenal biopsy specimens and eight control specimens. Tyrosine phosphorylation could be detected by flow cytometry on duodenal enterocytes and this expression was up regulated by pretreatment with epidermal growth factor. Tyrosine phosphorylation decreased with progression from the villus to the crypt, however, and was virtually undetectable on crypt enterocytes. Immunohistochemistry of the coeliac duodenum showed virtually absent tyrosine phosphorylation in the crypt. Increased tyrosine phosphorylation was detected in the infiltrating T cells. In conclusion, tyrosine phosphorylation in the duodenum is confined to the non-proliferative villous epithelium and is virtually undetectable in the proliferative crypt compartment. These findings suggest that tyrosine kinase activity is not a significant factor in the regulation of crypt cell proliferation in the human duodenum either in normal subjects or in coeliac disease patients.

CD3 Complex↗
PubMed1995

Detecting deletions in the critical region for lissencephaly on 17p13.3 using fluorescent in situ hybridisation and a PCR assay identifying a dinucleotide repeat polymorphism.

During a study of lissencephaly in England and Wales, 23 children were identified with this diagnosis. They were classified as follows: three children had Miller-Dieker syndrome (MDS), 13 had isolated lissencephaly sequence (ILS), two had type II lissencephaly, and five children were reclassified as focal or diffuse cortical dysplasia. Microdeletions of chromosome 17p13.3, also known as the Miller-Dieker critical region, have been associated with both MDS and ILS. We used the commercially available Oncor probe for fluorescent in situ hybridisation (FISH) studies on 14 patients and a further four were studied elsewhere. Deletions were identified in all three MDS patients and two of the ILS patients. These results are consistent with previously reported data. No deletions were found in those patients with focal or diffuse cortical dysplasia. In addition, a CA repeat polymorphism which maps to the Miller-Dieker critical region was studied in 12 families and was informative in nine; the results were consistent with the FISH data. We conclude that FISH is a reliable method to detect deletions in patients with MDS and ILS and also useful to identify chromosome rearrangements in their parents which are not detected by conventional cytogenetic analysis. The PCR assay, if informative, is also reliable and a useful alternative if only DNA is available. None of the five children with atypical radiological features had a deletion. We therefore suggest that as well as looking for other aetiologies a careful review of the diagnosis should be made of the MDS or ILS cases in whom a deletion is not found.

Brain↗
PubMed1995

Early identification of interleukin-16 (lymphocyte chemoattractant factor) and macrophage inflammatory protein 1 alpha (MIP1 alpha) in bronchoalveolar lavage fluid of antigen-challenged asthmatics.

Accumulation of CD4+ interleukin (IL)-2R+ lymphocytes in the airways of asthmatics is generally attributed to the presence of chemoattractant cytokines. The precise mechanism for the initiation of the earliest CD4+ lymphocyte infiltration and activation is unknown. In this study, we describe for the first time the presence of lymphocyte chemoattractant activity in the bronchoalveolar lavage (BAL) fluid obtained from asthmatics 6 h after antigen challenge. The majority of the chemoattractant activity at this early time point is represented by IL-16 (lymphocyte chemoattractant factor), a CD4+ cell-specific chemoattractant and growth factor. In addition to IL-16, macrophage inflammatory protein 1 alpha (MIP1 alpha) chemotactic bioactivity was detected in significant levels. While IL-16, MIP1 alpha, and IL-8 were all identified by enzyme-linked immunosorbent assay, the great majority of the lymphocyte chemoattractant activity in the BAL fluid after antigen challenge is attributable to IL-16 and MIP1 alpha. There were no detectable levels of IL-16 nor MIP1 alpha in BAL fluid of antigen-challenged normal subjects nor atopic nonasthmatics nor in saline-challenged lobes from the asthmatics. The identification of multiple lymphocyte chemoattractants early after antigen challenge suggests a complex cellular, as well as chemoattractant cytokine, profile in initiating the CD4+ T cell-mediated inflammatory process that is specific for the atopic asthmatic phenotype.

Adult↗
PubMed1995

A quantitative study on the myelinated fiber innervation of the periodontal ligament of cat canine teeth.

The periodontal ligament is richly innervated with mechanosensitive afferent nerve fibers, and the location of the mechanoreceptive terminals within the ligament is of functional significance. In this study, we have obtained quantitative information on mechanoreceptor distribution in the lower canine teeth of the cat. Using light microscopy, we quantified the number of myelinated axons in the periodontal ligament at 1 mm, 3 mm, and 5 mm from the tooth root apex. Grouped axons and axons which were isolated in the cemental half of the ligament (and therefore putative mechanoreceptors) were identified. The mean total number of axons was 1290 (n = 20) at 1 mm from the apex, 1290 at 3 mm, and 814 at 5 mm. The distribution of axons around the tooth root circumference was found to be non-uniform. Near the root apex, the highest numbers of grouped axons were located distally and mesially, and in the middle region of the root, the highest numbers were found mesially. The highest numbers of isolated axons at the apical levels were located distally, and in the mid-root region, mesially. At all levels, the lingual region was the most sparsely innervated by both groups. There was a positive correlation between the number of grouped axons and the width of the ligament in the same region, but this correlation was much weaker for isolated axons, suggesting that their distribution does not result only from the volume of tissue. Variations in the number of axons and, to a lesser extent, the dimensions of the periodontal ligament were considerable.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Adhesion molecule expression on gastric intra-epithelial lymphocytes of patients with Helicobacter pylori infection.

OBJECTIVE: To examine the expression of adhesion molecules on gastric intra-epithelial lymphocytes (IELs) from patients infected with Helicobacter pylori. DESIGN: The expression of adhesion molecules and T-cell activation markers by gastric IELs from patients with gastritis or duodenal ulceration was examined using two-colour flow cytometry. Ten of the patients were H. pylori positive and eight were H. pylori negative. RESULTS: Expression of lymphocyte function-associated antigen-1 (LFA-1) on IELs was significantly lower (P < 0.05) in patients with H. pylori infection than in patients negative for H. pylori. There were no significant differences in the expression on IELs of intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), human mucosal lymphocyte (antigen)-1 (HML-1), very late antigen-4 (VLA-4) or CD43 between H. pylori-positive and H. pylori-negative individuals. In addition, the transferrin receptor, a maker associated with proliferation and activation, was found on a small population of IELs from H. pylori-positive individuals. CONCLUSION: A reduction in the expression of LFA-1 has previously been reported on activation of IELs. The finding of reduced LFA-1 expression and increased transferrin receptor expression on IELs from H. pylori-positive individuals suggests that activation of these cells is associated with H. pylori infection.

Case-Control Studies↗
PubMed1995

Protein kinase C isoform expression in CD45RA+ and CD45RO+ T lymphocytes.

Differences in levels of specific enzymes utilized in intracellular signalling could be a factor in the distinct signalling properties observed in memory and naive T cells. We have studied the expression of both classical and non-classical protein kinase of C (PKC) isoenzymes in CD45RA and CD45RO cells using a combination of Western blot and flow cytometric analysis. These data indicate that CD45RA cells express higher levels of PKC alpha, PKC beta and PKC delta than CD45RO cells. In addition, CD45RA+ cells show greater proliferative activity when stimulated with phorbol myristate acetate (PMA) and calcium ionophore than their CD45RO+ counterparts. Variations in the levels of these isoenzymes could be implicated in functional differences, such as proliferation and cytokine production, in these cell subsets.

Animals↗
PubMed1994

Idiotypic vaccination against human B-cell lymphoma. Rescue of variable region gene sequences from biopsy material for assembly as single-chain Fv personal vaccines.

Idiotypic determinants on neoplastic B cells could provide tumor antigens for vaccination of patients with B-cell tumors. Because this approach requires an individual vaccine for each patient, simple methods for obtaining idiotypic antigen are desirable. Using polymerase chain reaction (PCR) with family-based V-gene and J-region primers, the variable region genes of heavy and light chains (VH and VL) of Ig have been obtained from biopsy material from 13 patients with B-cell tumors. In each case, analysis of random clones derived from the PCR product showed repeated, clonally-related sequences, whereas normal lymphoid tissue generated no repeated sequences. In 3/3 cases, the repeated sequences were found to be the same as those in a tumor-derived hybridoma. Mutational patterns in the V-genes differed among the tumors, with follicular lymphoma tending to be more highly mutated. The individual VH and VL sequences have been assembled with a flexible linker sequence to encode single-chain Fv (scFv). The scFv sequences can be cloned into bacterial expression vectors to produce protein, or into vectors suitable for direct vaccination using naked DNA. In a model system, expressed scFv protein retained all idiotypic determinants defined by a panel of five anti-idiotypic monoclonal antibodies (MoAbs). Similarly, expressed scFv proteins from two patients were shown to react with anti-idiotypic antibodies. This approach allows production of potential vaccines from surgical biopsies within 2 to 3 weeks.

Amino Acid Sequence↗
PubMed1994

The demand for and use of outcomes information.

As the focus of UK health care moves towards the achievement of health gain, information on health outcomes is required by health care commissioners and providers in order to bring about improved patient outcomes. The information required includes health care activity and population data, and textual and bibliographic information to identify published outcomes studies and current health outcomes activities. A survey of enquiries received by the UK Clearing House on Health Outcomes was undertaken to ascertain the nature and level of enquiries, and their geographical and organizational origins in the UK. The study cannot claim to be a comprehensive review of the demand for and use of health outcomes information. What it does illustrate is the still developmental stage of health outcomes activity in the UK. Providers are the major group of users of outcomes information. The potential impact of health outcomes information on health care commissioning has yet to be realized.

Data Collection↗
PubMed1994

Guidelines for blood utilization review.

Hospitals are required by accrediting agencies to perform blood utilization review. Specific areas that must be addressed are the ordering, distribution, handling, dispensing, and administration of blood components. Monitoring the effects of transfusion on patients is also required. The format of the review process and the criteria for appropriate blood utilization must be developed by each institution. This article provides examples of areas that can be reviewed and procedures that may be used. However, the suggested laboratory values must not be interpreted as defining indications or criteria for transfusion. Each transfusion committee, or its equivalent, is responsible for developing its own institutional blood utilization procedures and audit criteria. Review and approval by the medical staff prior to implementation are essential. The procedures must also be reviewed and revised on a regular basis.

Blood Transfusion↗
PubMed1994

An exploration of women's perceptions of the major factors that contributed to their alcohol abuse.

The purpose of this research was to explore the interviewees' perceptions of the major factors that contributed to their alcohol abuse. The research was carried out by interviewing seven women who were identified by community mental health professionals. The research was qualitative and exploratory. The semi-structured tape-recorded interview technique was used as an enquiry tool. The tapes were then transcribed and coded, and the findings were scrutinized and scanned for emerging themes and concepts using an interactive and cyclical process of data-reduction techniques, data display and verification of findings. The findings suggest that the majority of the interviewees could identify and isolate specific life events and past-life crises that contributed to an increase in their alcohol intake. Results also indicate that there is a need to consider the efficacy of the current models of primary, secondary and tertiary care as well as relapse-prevention programmes of care in order to facilitate women to have every opportunity to make informed and rational health choices about their drinking behaviours, and to maintain abstinence, for the promotion of positive mental health and for enhancing the quality of their lives.

Adult↗