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Biomedical subjects

P Lewis

Publications and source records attributed to P Lewis.

At least 55 records · Page 3Linked to original sources
PubMed2000

Scintigraphy in the foot and ankle.

Nuclear medicine provides a number of sensitive, although unfortunately not always specific techniques, for the evaluation of foot pain and suspected infection. In most patients the 3 phase bone scan is the initial means of evaluation, with a labeled white cell scan included when osteomyelitis is suspected. Nuclear medicine studies must be interpreted with knowledge of the patient's history and symptoms and with close correlation to plain film findings. Attention to detail when acquiring images, possibly with the addition of SPECT or pinhole images in difficult patients, results in excellent anatomic localization in most patients.

Ankle↗
PubMed1999

Incorporation of esterified soybean isoflavones with antioxidant activity into low density lipoprotein.

We have recently reported that dietary intake of soybean isoflavone phytoestrogens resulted in increased oxidation resistance of isolated low density lipoprotein (LDL). In order to explore the underlying mechanisms we designed two types of in vitro experiments. First, we prepared several different isoflavone fatty acid esters to increase their lipid solubility and studied their incorporation into LDL. Second, the oxidation resistance of the isoflavone-containing LDLs was investigated with Esterbauer's 'conjugated diene' method using Cu2+ as prooxidant. Unesterified daidzein and genistein as well as genistein stearic acid esters were incorporated into LDL to a relatively small extent (0.33 molecules per LDL particle, or less) and they did not significantly influence oxidation resistance. The oleic acid esters of isoflavones were incorporated more effectively, reaching a level of 2.19 molecules per LDL particle or more, and the 4',7-O-dioleates of daidzein and genistein exhibited prolongations of lag times by 46% (P<0.05) and 202% (P<0.01), respectively. A smaller but significant increase in lag time (20.5%, P<0.01) was caused by daidzein 7-mono-oleate. In summary, esterification of soybean isoflavones daidzein and genistein with fatty acids at different hydroxyl groups provided lipophilicity needed for incorporation into LDL. Some isoflavone oleic acid esters increased oxidation resistance of LDL following their incorporation.

Antioxidants↗
PubMed1999

Antigenic variation among bovine enteric coronaviruses (BECV) and bovine respiratory coronaviruses (BRCV) detected using monoclonal antibodies.

Bovine coronavirus (BCV) causes neonatal calf diarrhea (CD) and is associated with winter dysentery (WD) in adult dairy cattle. It can also be isolated from the respiratory tracts of cattle entering feedlots. Monoclonal antibodies (MAbs) specific for the hemagglutinin esterase (HE) and spike (S) surface proteins of 2 bovine enteric coronavirus (BECV) strains and two bovine respiratory coronavirus (BRCV) strains were tested against 6 BECV strains and 6 recently isolated BRCV strains, in order to characterize the antigenicity of BCV strains with varied tissue tropisms. All MAbs had high immunofluorescence (IF) titers against BECV and BRCV strains, indicative of conserved cross-reactive epitopes. In hemagglutination inhibition (HI) tests, the S-MAbs were more broadly reactive than HE-MAbs. The BRCV and CD MAbs were more broadly reactive in HI than the WD MAbs. The HA activity of the Mebus vaccine CD strain was not inhibited by any of the MAbs tested. The HI activity of BRCV strain R6 was unique among the 6 BRCV isolates. In virus neutralization assays, MAbs to the BRCV strain R4 neutralized all 6 BECV strains tested. Antigenic variation exists among both BECV and BRCV strains, but it cannot be attributed soley to the clinical origin of the strain.

Animals↗
PubMed1999

Loss of chromosome 10 is an independent prognostic factor in high-grade gliomas.

Loss of heterozygosity (LOH) for chromosome 10 is the most frequent genetic abnormality observed in high-grade gliomas. We have used fluorescent microsatellite markers to examine a series of 83 patients, 34 with anaplastic astrocytoma (grade 3) and 49 with glioblastoma multiforme (grade 4), for LOH of chromosome 10. Genotype analysis revealed LOH for all informative chromosome 10 markers in 12 (35%) of patients with grade 3 and 29 (59%) grade 4 tumours respectively, while partial LOH was found in a further eight (24%) grade 3 and ten (20%) grade 4 tumours. Partial LOH, was confined to the long arm (10q) in six and the short arm (10p) in three cases, while alleles from both arms were lost in four cases. Five tumours (one grade 3 and four grade 4) showed heterogeneity with respect to loss at different loci. There was a correlation between any chromosome 10 loss and poorer performance status at presentation (chi2 P = 0.005) and with increasing age at diagnosis (Mann-Whitney U-test P = 0.034) but not with tumour grade (chi2 p= 0.051). A Cox multivariate model for survival duration identified age (proportional hazards (PH), P= 0.004), grade (PH, P= 0.012) and any loss of chromosome 10 (PH, P= 0.009) as the only independent prognostic variables. Specifically, LOH for chromosome 10 was able to identify a subgroup of patients with grade 3 tumours who had a significantly shorter survival time. We conclude that LOH for chromosome 10 is an independent, adverse prognostic variable in high-grade glioma.

Brain Neoplasms↗
PubMed1999

Studies of human immunodeficiency virus type 1 mucosal viral shedding and transmission in Kenya.

If human immunodeficiency virus type 1 (HIV-1) vaccines are to be highly effective, it is essential to understand the virologic factors that contribute to HIV-1 transmission. It is likely that transmission is determined, in part, by the genotype or phenotype (or both) of infectious virus present in the index case, which in turn will influence the quantity of virus that may be exchanged during sexual contact. Transmission may also depend on the fitness of the virus for replication in the exposed individual, which may be influenced by whether a virus encounters a target cell that is susceptible to infection by that specific variant. Of interest, our data suggest that the complexity of the virus that is transmitted may be different in female and male sexual exposures.

Adult↗
PubMed1999

Subtypes of human immunodeficiency virus type 1 and disease stage among women in Nairobi, Kenya.

In sub-Saharan Africa, where the effects of human immunodeficiency virus type 1 (HIV-1) have been most devastating, there are multiple subtypes of this virus. The distribution of different subtypes within African populations is generally not linked to particular risk behaviors. Thus, Africa is an ideal setting in which to examine the diversity and mixing of viruses from different subtypes on a population basis. In this setting, it is also possible to address whether infection with a particular subtype is associated with differences in disease stage. To address these questions, we analyzed the HIV-1 subtype, plasma viral loads, and CD4 lymphocyte levels in 320 women from Nairobi, Kenya. Subtype was determined by a combination of heteroduplex mobility assays and sequence analyses of envelope genes, using geographically diverse subtype reference sequences as well as envelope sequences of known subtype from Kenya. The distribution of subtypes in this population was as follows: subtype A, 225 (70.3%); subtype D, 65 (20.5%); subtype C, 22 (6.9%); and subtype G, 1 (0.3%). Intersubtype recombinant envelope genes were detected in 2.2% of the sequences analyzed. Given that the sequences analyzed represented only a small fraction of the proviral genome, this suggests that intersubtype recombinant viral genomes may be very common in Kenya and in other parts of Africa where there are multiple subtypes. The plasma viral RNA levels were highest in women infected with subtype C virus, and women infected with subtype C virus had significantly lower CD4 lymphocyte levels than women infected with the other subtypes. Together, these data suggest that women in Kenya who are infected with subtype C viruses are at more advanced stages of immunosuppression than women infected with subtype A or D. There are at least two models to explain the data from this cross-sectional study; one is that infection with subtype C is associated with a more rapid disease progression, and the second is that subtype C represents an older epidemic in Kenya. Discriminating between these possibilities in a longitudinal study will be important for increasing our understanding of the role of specific subtypes in the transmission and pathogenesis of HIV-1.

Base Sequence↗
PubMed1999

An analysis of the communication tactics used by hearing-impaired adults.

The aim of this study was to establish whether and to what degree certain types of communication strategies (hearing tactics) used by hearing-impaired adults could be shown to co-occur, and to find out which strategies were more likely to be used in which type of communicative situations. A consecutive series of 100 patients attending an audiological rehabilitation clinic was given a questionnaire asking how often they used each of five different hearing tactics in 11 different situations. 'Avoidance' and 'request for repetition' were the tactics used most commonly. 'Pretending to hear/understand' and 'positioning self to improve hearing' were used less frequently, with 'interruption' the least commonly used. There was some association between tactics and situations but no clear picture emerged. In a reassessment of our methodology and results, we suggest that the future research of communication strategies would benefit from a sociolinguistic approach based on the qualitative analysis of naturally occurring discourse (conversation) of hard-of-hearing people, focusing on the use of different strategies in relation to communicators' goals in interaction.

Adolescent↗
PubMed1999

Job satisfaction in a rural differentiated-practice setting.

This article reports the findings of a 3-year study that assessed the job satisfaction of nursing personnel in a rural nursing center that uses a differentiated practice model. Job satisfaction was measured using the Brayfield Job Satisfaction Questionnaire, the McCloskey/Mueller Satisfaction Survey, and the Job Descriptive Index. A high level of job satisfaction was found across all 3 years. Factors associated with job satisfaction are also described. The findings of this study add to the growing body of literature on the importance of differentiated practice in creating satisfying work environments.

Community Health Nursing↗
PubMed1999

Dealing with drug-seeking patients: the Tripler Army Medical Center experience.

Patients who exhibit drug-seeking behavior are a chronic problem in most health care delivery settings. In June 1996, Tripler Army Medical Center, a tertiary care hospital serving approximately 300,000 beneficiaries, implemented a sole provider program to identify and help such patients. A multidisciplinary sole provider team assigns a sole provider to identified drug seekers. Twice a year, the team scans a printout of all prescriptions for controlled substances to identify suspicious drug usage patterns. The team also accepts referrals from health care providers. This article describes the program and reports on results, problems encountered, and steps taken to improve its efficacy.

Adult↗
PubMed1999

The retroperitoneal approach to unusual abdominal aortic aneurysms.

A retroperitoneal approach was used to repair an infrarenal abdominal aortic aneurysm in three patients. The technique was used because of unusual pathology obscuring the aneurysm neck. We discuss the technique of retroperitoneal exposure and suggest advantages over conventional transperitoneal repair in patients with uncomplicated infrarenal abdominal aortic aneurysm.

Aged↗
PubMed1998

Improved freedom from PSA failure with whole pelvic irradiation for high-risk prostate cancer.

PURPOSE: To determine the impact of whole pelvic irradiation on the risk of PSA failure in prostate cancer patients, at high predicted risk for lymph node involvement, receiving definitive radiotherapy. MATERIALS AND METHODS: Between October 1987 and December 1995, 506 patients with clinically localized prostate cancer were treated with definitive radiotherapy at UCSF and affiliated institutions. Treatment consisted of 4-field whole pelvic irradiation followed by a prostate-only boost, or prostate-only treatment (median follow-up was 35 months and 30 months, respectively). PSA failure was defined as: 1. a PSA value > or = 1 ng/ml; or 2. a PSA value that rose > or = 0.5 ng/ml in < or = 1 year posttreatment on two consecutive measurements, with the first rise defined as the time of failure. The calculated risk of lymph node positivity (%rLN+) was defined as 2/3(iPSA) + 10(GS-6), and high risk was defined as %rLN+ > or = 15%. Univariate and multivariate analyses were performed. RESULTS: A total of 201 high-risk patients were identified. High-risk patients who received whole pelvic irradiation had significantly improved freedom from PSA failure compared to those who received prostate-only treatment (median PFS = 34.3 months vs. 21.0 months; p = 0.0001). Potential confounding variables, including initial PSA, Gleason score, T stage, radiation dose, year of treatment, use of three-dimensional (3D) conformal techniques, and use of hormone therapy, did not account for the observed difference in time to PSA failure. Multivariate analysis revealed type of radiation treatment to be the most significant independent predictor of outcome. CONCLUSION: Whole pelvic radiotherapy significantly improves the PSA failure-free survival in patients with a high calculated risk of lymph node positivity.

Analysis of Variance↗
PubMed1998

Ticlopidine-induced neutropenia mimicking sepsis early after intracoronary stent placement.

We report a case of ticlopidine-induced profound neutropenia early in the course of therapy, which was manifest as a febrile systemic illness mimicking sepsis. This clinical presentation was potentially indicative of a contaminated intracoronary stent. The patient's signs and symptoms of illness promptly resolved with removal of ticlopidine, and no infection was documented. Review of indications for ticlopidine use, potential adverse effects, and monitoring recommendations are discussed.

Coronary Angiography↗