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Biomedical subjects

J Walker

Publications and source records attributed to J Walker.

At least 163 records · Page 9Linked to original sources
PubMed1998

Barriers to care among persons living with HIV/AIDS in urban and rural areas.

People living with HIV disease, particularly those in small towns and rural areas, face many barriers that prevent them from receiving important life-care services. We developed the Barriers to Care Scale (BACS) to delineate the problem severity of factors that impede care and service provision among a sample of 226 men and women living with HIV disease in a single midwestern state. Both urban and rural respondents indicated that major barriers to life-care services included the lack of knowledge about HIV among citizens in the community, insufficient personal financial resources, the lack of employment opportunities for people living with HIV, and the lack of supportive and understanding work environments. Rural persons living with HIV disease, compared to their urban counterparts, assigned significantly higher problem severity ratings to the following barriers: the need to travel long distances to medical facilities and personnel; a shortage of adequately trained medical and mental health professionals; a lack of personal or public transportation; and community residents' stigma toward people living with HIV. The large number of barriers to care identified in the present study indicates that innovative programmes designed to remove these barriers and improve the life quality of rural persons living with HIV are urgently needed.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Regulation of in vitro and in vivo T cell activation by CD43.

Accessory molecule interactions can be critical in determining the outcome of a T cell's encounter with antigen. Cell adhesion proteins may augment T cell responses by facilitating TCR engagement of the antigen-MHC complex, while co-stimulatory molecules may deliver distinct signals that modulate T cell responsiveness. CD43 (leukosialin, sialophorin) has been suggested to influence cell activation by steric hindrance based upon the large size and glycosylation of the protein, as well as the relative abundance of the protein on the cell surface. In this paper we examine both in vitro and in vivo T cell-dependent responses in CD43-deficient mice. We demonstrate that T cells from CD43-deficient mice are hyper-responsive following both in vivo and in vitro activation, and that this is observed in response to not only TCR-CD3-mediated stimulation, but also following receptor-independent activation. This data suggests that mechanisms other than non-specific steric hindrance are important in the regulation of T cell activation by CD43.

Animals↗
PubMed1998

Amonafide in patients with leiomyosarcoma of the uterus: a phase II Gynecologic Oncology Group study.

Twenty-six evaluable patients who had leiomyosarcoma of the uterus were treated with amonafide, 300 mg/m2, for 5 consecutive days every 3 weeks. One partial response (4%) resulted. Hematologic toxicity was substantial, with grade 3 or 4 events occurring as follows: leukopenia, 12 patients (46%); thrombocytopenia, 4 patients (15%); and granulocytopenia, 7 patients (27%). One patient had transient grade 4 renal failure. Considering the poor activity and substantial toxicity that was observed, no further studies are planned by the Gynecologic Oncology Group using amonafide at this dose schedule in leiomyosarcomas.

Adenine↗
PubMed1998

Treatment of femur fracture with associated head injury.

OBJECTIVES: The aim of this study was to determine (a) whether delay in femur fracture stabilization beyond twenty-four hours in patients with head injury increased the risk of pulmonary complications and (b) whether immediate (up to twenty-four hours) femur fracture stabilization increased the risk of central nervous system (CNS) complications. DESIGN: Retrospective analysis. MATERIALS AND METHODS: Thirty-two patients with femur fracture and head injury were identified. Fourteen underwent immediate stabilization of their fractures, and eighteen underwent delayed (four-teen patients) or no (four patients) stabilization of their fractures. RESULTS: In the immediate stabilization group, five patients had severe head injuries [Glasgow Coma Score (GCS) < or = 8] and nine had mild head injuries (GCS > 8). In the mild head injury group, no patient had a pulmonary complication and one had a CNS complication. In the severely head-injured group, one patient had a pulmonary complication and no patient had a CNS complication. In the delayed stabilization group, six patients had mild head injuries (GCS > 8) and twelve had severe head injuries (GCS < or = 8). In the mildly head injured group, one patient had a pulmonary complication, two patients had CNS complications, and one patient died. In the severely head injured group, nine patients had pulmonary complications, three patients had CNS complications, and one patient died. Logistic regression identified delay in femur stabilization as the strongest predictor of pulmonary complication (p = 0.0042), followed by severity of chest Abbreviated Injury Score (AIS; p = 0.0057) and head AIS (p = 0.0133). Delaying fracture stabilization made pulmonary complications forty-five times more likely. Each point increase in the chest AIS and head/neck AIS increased the risk of pulmonary complication by 300 percent and 500 percent, respectively. A statistically significant predictor of CNS complications could not be identified by using logistic regression. CONCLUSION: Delay in stabilization of femur fracture in head-injured patients appears to increase the risk of pulmonary complications. However, due to selection bias in this patient sample, this question cannot be definitively answered. Early fracture stabilization did not increase the prevalence of CNS complications.

Adolescent↗
PubMed1998

Managing chronic nonmalignant pain with continuous intrathecal morphine.

One alternative to traditional treatment modalities for chronic pain is continuous intrathecal administration of morphine via an implanted pump. However, relatively little is known about the benefits and long-term complications of this therapy for chronic nonmalignant pain. The purpose of this study was to describe patient responses to continuous intrathecal morphine over the course of one year with respect to morphine dosage used, complications and subjective assessments of pain. Data were obtained from twelve patients who completed one year of therapy. After one year, a 42% reduction in pain as measured by the McGill pain questionnaire had occurred (p < .01). A similar 41% reduction in pain was also present based on the Verbal Descriptor Scale (p < .01). A 35% reduction in the perceived hardship of pain was present (p < .01) accompanied by anecdotal comments that an improvement in the ability to manage activities of daily living had occurred. One patient was able to return to work. A statistically nonsignificant increase in the mean daily dosage of morphine occurred and few long-term adverse effects were present. Complications of implantation occurred in 33.3% of the patients and were successfully managed without discontinuing therapy. In selected patients with chronic pain, intrathecal administration of morphine via an implanted pump can reduce pain with minimal long-term adverse effects or complications.

Adolescent↗
PubMed1998

A high-resolution microsatellite map of the mouse genome.

The European Collaborative Interspecific Backcross (EUCIB) resource was constructed for the purposes of high-resolution genetic mapping of the mouse genome (). The large Mus spretus/C57BL/6 backcross of 982 progeny has a genetic resolution of 0.3 cM at the 95% confidence level ( approximately 500 kb in the mouse genome). We have used the EUCIB mapping resource to develop a genome-wide high-resolution genetic map incorporating 3368 microsatellites. The microsatellites are distributed among 2302 genetically separated bins with 1.46 markers per bin on average. Average bin separation is 0.61 cM. This high-resolution genetic map will aid the construction of a robust physical map of the mouse genome.

Animals↗
PubMed1998

Obstacles to timely neonatal screening in North Thames.

OBJECTIVE: To assess the timeliness of neonatal (Guthrie card) screening in North Thames, and to identify the most effective ways of improving it. DESIGN: Analysis of information routinely collected in the course of neonatal screening; reanalysis of published data on blood phenylalanine concentration in phenylketonuria (PKU) over the first two weeks; simulation studies on the impact of different interventions. SUBJECTS: 100,690 infants born over one year and screened at Great Ormond Street Hospital NHS Trust. OUTCOME MEASURE: Interval between birth and reading PKU screen results. RESULTS: Although 75% of samples (district range 55-91%) were collected by day 7, only 81% had arrived in the laboratory seven days later (range 57-96%). The average interval between birth and reading results was 14.5 days, with only 9.7% read by day 10. Samples could be collected from day 4 without significant impact on false negative rates for PKU. If samples were collected from day 4 and posted promptly (second class), the average interval between birth and reading results could be reduced to 9.3 days. If first class mail were used and the laboratory operated on Saturdays, and used assays that could be read the same day rather than bacterial inhibition assays, the average would be 7.8 days, with 96% read by day 10. CONCLUSION: Timeliness of neonatal screening shows unacceptable variation between districts, and delays in dispatch of specimens to the laboratory. Same day, first class posting should be introduced, and samples could be collected between days 4 and 8.

Blood Specimen Collection↗
PubMed1998

Elaboration of matrix metalloproteinase inhibitors by human skin in organ culture and by skin cells in monolayer culture: relationship to invasion.

Functional and immunochemical approaches were used to assess matrix metalloproteinase (MMP) inhibitors, e.g., tissue inhibitor of metalloproteinases 1 and 2 (TIMP-1 and TIMP-2), in organ cultures of normal human skin maintained under growth factor free conditions or in medium supplemented with a combination of growth factors including epidermal growth factor, insulin, and pituitary extract. It has previously been shown that under growth factor free conditions, normal skin structure and function are maintained for several days, while in the presence of these exogenous growth factors, the epithelial cells invade the stroma [Invasion and Metastasis 1993;13:225-233]. TIMP-1 was detected in equivalent amounts in organ culture fluids under both conditions. TIMP-2 was not detected under either condition. Normal epidermal keratinocytes, normal dermal fibroblasts, and three different epithelial tumor cell lines were also examined for MMP inhibitor expression. Keratinocytes and fibroblasts produced high levels of both TIMP-1 and TIMP-2, but in neither cell type was there a significant difference between growth factor free and growth factor containing conditions. In contrast, the three epithelial tumor cell lines produced low to undetectable levels of both TIMP-1 and TIMP-2. These data suggest that acquisition of local invasive capacity is not dependent on a reduction in MMP inhibitor expression. A reduction in MMP inhibitors may accompany the transition from invasive to metastatic tumors.

Blotting, Western↗
PubMed1998

The transition to registered nurse: the experience of a group of New Zealand degree graduates.

Since 1991, entry to the nursing profession in New Zealand has primarily been through a three year degree programme. The purpose of this study was to explore the issues faced by a group of degree graduates in their first year of registered nurse practice and to identify if the degree outcomes (such as critical thinking, problem solving, reflection on practice, research, independent learning and using cultural safety knowledge) had mediated this transition process. Purposive sampling was used to invite five female graduates to take part in two focus groups, one held at 4 months and the other at 9 months after starting work. Qualitative data were collected using semi-structured questions and the taped interviews were analysed for themes. Five themes were identified: accepting responsibility, accepting their level of knowledge, becoming a team member, professional standards, and workplace conditions. Graduates were using their cultural safety knowledge but they perceived their knowledge of research was linked to further academic study. Their ability to critique their own practice was evident but they found it more difficult to challenge their colleagues' practice and the wider agency culture. Implications of the study are discussed in relation to nursing education and preceptor programmes and areas for further research are indicated.

Adaptation, Psychological↗
PubMed1998

Molecular characterisation of methicillin resistant Staphylococcus aureus.

Finer discrimination between strains of methicillin resistant Staphylococcus aureus (MRSA) than phage typing can provide is needed to identify and characterise spread of infection in outbreaks. This study compares three molecular methods with each other and with phage typing. Pulsed field gel electrophoresis provides the greatest discrimination, but finer discrimination is obtainable by combining methods.

Bacterial Typing Techniques↗
PubMed1997

Schistosomiasis in Australian travellers to Africa.

OBJECTIVE: To determine the proportion of Australian travellers to Africa at risk of Schistosoma infection, and the proportion of those infected. DESIGN AND PARTICIPANTS: Retrospective postal survey of 360 patients who had attended Fairfield Hospital travel clinic in 1994 and stated an intention to travel to Malawi, Zimbabwe or Botswana. MAIN OUTCOME MEASURES: Self-reported risk status for Schistosoma infection. For those at risk, results of an indirect haemagglutination assay (IHA). For those with IHA titres > or = 1:32, results of enzyme-linked immunosorbent assay, urine microscopy and eosinophil count. RESULTS: 360 letters were sent; 35 were returned to sender. Of the 325 remaining, 250 (77%) either responded or had an IHA test; 19 of these were still overseas or did not travel. 117/231 (51%) returned travellers considered themselves at risk of infection. Significantly fewer older patients reported exposure (chi 2 = 66.6; P < 0.001). 109/117 (93%) of those at risk had IHA tests and 18 had titres > or = 1:32. Subsequent testing indicated infection in 10/117 travellers (8.5%; 95% CI, 4.2%-15.2%). CONCLUSION: Our findings indicate that a considerable number of Australian travellers to Africa are at risk of schistosomiasis, and some are infected. As complications can be serious, screening is recommended for individuals with any risk of infection, and treatment should be offered to those infected.

Adult↗
PubMed1997

Gastrointestinal cancer mortality of workers in occupations with high asbestos exposures.

Asbestos, which is a well-known risk factor for lung cancer and malignant mesothelioma, has also been suggested as a gastrointestinal (GI) carcinogen. This study was conducted to assess the relationship between high asbestos exposure occupations and the occurrence of G1 cancer. Death certificate data were analyzed from 4,943,566 decedents with information on occupation and industry from 28 states from 1979 through 1990. Elevated proportionate mortality ratios (PMRs) for mesothelioma were used to identify occupations potentially having many workers exposed to asbestos. All PMRs were age-adjusted and sex- and race-specific. The PMRs for GI cancers in white males were then calculated for these occupations after excluding mesothelioma, lung cancer, and non-malignant respiratory disease from all deaths. We identified 15,524 cases of GI cancer in the 12 occupations with elevated PMRs for mesothelioma. When these occupations were combined, the PMRs for esophageal, gastric, and colorectal cancer were significantly elevated at 108 (95% confidence interval = 107-110), 110 (106-113), and 109 (107-110), respectively. Esophageal cancer was elevated in sheet metal workers and mechanical workers. Gastric cancer was elevated in supervisors in production and managers. Colorectal cancer was elevated in mechanical and electrical and electronic engineers. However, high exposure occupations like insulation, construction painter supervisors, plumbers, furnace operators, and construction electricians showed no elevations of GI cancers. In conclusion, this death certificate study supports an association between asbestos exposure and some GI cancer, however the magnitude of this effect is very small.

Asbestos↗
PubMed1997

Using distance matrices to choose between competing theories and an application to the origin of modern humans.

This paper examines competing theories for cases in which both the data and the hypotheses can be represented as distance matrices. A test due to Dow & Cheverud has been used for such comparisons in anthropology, but when data are spatially, temporally, or phylogenetically autocorrelated, this test may be far too liberal. We examine a classification procedure based on ratios of probabilities obtained from Mantel tests of the competing hypotheses and find that design matrices describing only lag-one connections and those eliminating common connections of competing hypotheses are the most informative. We apply this method to simulated gene-frequency data in a 7 x 7 chessboard representing a stepping-stone model and discriminate between alternative theories with a 7% misclassification rate. We also apply these techniques to the current controversy concerning the origin of anatomically modern humans by testing design matrices representing regional continuity and single African origins. The outcome for lag-one matrices and those showing only unique lag-one differences indicate that the single African origin of anatomically modern humans fits the distance matrix based on 165 characters of 83 fossil crania better than the competing theory. However, we also tested a design matrix describing single origin out of southwest Asia. This design matrix was clearly most similar to the data in all tested cases. These results make the regional-continuity theory a less likely explanation for the observed cranial differences than the two single-origin theories. Of these, single southwest Asian origins seems the more likely interpretation of the data.

Biological Evolution↗
PubMed1997

Inv(10)(p11.2q21.2), a variant chromosome.

We present 33 families in which a pericentric inversion of chromosome 10 is segregating. In addition, we summarise the data on 32 families in which an apparently identical inv(10) has been reported in the literature. Ascertainment was through prenatal diagnosis or with a normal phenotype in 21/33 families. In the other 12 families, probands were ascertained through a wide variety of referral reasons but in all but one case (a stillbirth), studies of the family showed that the reason for referral was unrelated to the chromosome abnormality. There has been, to our knowledge, no recorded instance of a recombinant chromosome 10 arising from this inversion and no excess of infertility or spontaneous abortion among carriers of either sex. We propose that inv(10)(p11.2q21.2) can be regarded as a variant analogous to the pericentric inversion of chromosome 2(p11q13). We conclude that prenatal chromosome analysis is not justified for inv(10) carriers. In addition, family investigation of carrier status is not warranted in view of the unnecessary concern this may cause parents and other family members.

Abortion, Spontaneous↗