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Biomedical subjects

D Wilson

Publications and source records attributed to D Wilson.

At least 199 records · Page 11Linked to original sources
PubMed1997

Hepatic lesion detection at MR imaging: a comparative study with four sequences.

PURPOSE: To compare results with the following magnetic resonance (MR) imaging sequences in the detection of focal hepatic lesions: fast spin-echo (SE) before and after administration of superparamagnetic iron oxide (SPIO) particles, fat-suppressed T2-weighted SE, and dynamic gadolinium-enhanced fast low-angle shot (FLASH). MATERIALS AND METHODS: In 26 patients with known malignancy and documented focal liver lesions, 1.0-T MR imaging was performed prior to hepatic resection. All images were reviewed independently by four blinded observers. Sensitivity was calculated for each sequence and for each observer by means of alternative-free-response receiver operating characteristic (ROC) methods. RESULTS: The mean area under the alternative-free-response ROC curve with SPIO-enhanced fast SE (0.85) was significantly greater (P < .02) than that with all other sequences. Detection was significantly improved with SPIO-enhanced fast SE compared with dynamic gadolinium-enhanced FLASH (which was the best of the other three sequences) for all lesions (P < .002) and for malignant lesions (P < .0002). CONCLUSION: Findings with the SPIO-enhanced fast SE sequence improved detection of focal liver lesions and had the highest diagnostic accuracy.

Adipose Tissue↗
PubMed1997

Quantification of circulating peptides and assessment of peptide uptake across the gastrointestinal tract of sheep.

Gastrointestinal absorption of peptides was examined in sheep fed a forage-based diet. Peptide concentrations were determined in arterial, portal, and mesenteric blood and plasma by quantification of amino acid concentrations before and after acid hydrolysis of samples that had been first deproteinized then subjected to Sephadex G-15 gel-filtration to remove residual protein. In contrast to other studies of ruminants, peptide concentrations for individual amino acids were lower than for the corresponding free amino acids with peptide (expressed as a proportion of total nonprotein amino acid) representing not more than .25 to .3 of total amino acid. Peptide concentrations in arterial, mesenteric, and portal blood and plasma were similar, indicating that on this diet there was no net uptake of peptides from the small intestine (mesenteric-drained viscera, MDV) or the whole tract (portal-drained viscera, PDV). Increasing the intake of alfalfa pellets from 800 to 1,200 g/d, while increasing the absorption and net flux across the MDV and PDV of free amino acids, had no effect on peptide absorption. Preparation of blood and plasma samples for peptide analysis with methods used in studies in which substantial peptide absorption has been reported indicated no net MDV or PDV flux of peptide. Such conflicting data on the extent of gastrointestinal peptide flux are discussed in the context of methodological differences and the importance of diet and physiological state of the animal.

Amino Acids↗
PubMed1997

Care maps across the continuum.

As hospital length of stay decreases and care shifts to the community, there is a need to develop approaches to ensure uniformity and continuity of care in patient groups. Care maps, multidisciplinary standards that outline the processes of care and expected outcomes within predetermined timeframes, can support a continuum of care from preadmission through hospital stay to discharge from community-based home care by clearly delineating standards across the entire episode of care. However, the development of successful care maps requires extensive collaboration, planning and evaluation.

Continuity of Patient Care↗
PubMed1997

Classical polyarteritis nodosa and microscopic polyarteritis with medium vessel involvement--a comparison of the clinical and laboratory features.

Microscopic polyarteritis may involve medium-sized and small blood vessels as well as arterioles, venules and capillaries. We have compared the clinical and laboratory features in patients with microscopic polyarteritis and medium vessel involvement, with the features found in patients with polyarteritis nodosa affecting medium vessels alone. In a 9-year period, 21 patients presented to our hospital with a form of polyarteritis. Seven had microscopic polyarteritis demonstrated histologically (6/7, 86%) and associated with dysmorphic urinary red cells (7/7, 100%), as well as medium vessel vasculitis demonstrated histologically (7/7) or by angiography (1/7, 14%). Five patients had polyarteritis nodosa with medium vessel vasculitis demonstrated histologically (3/5, 60%) or by angiography (2/5, 40%); and no evidence of a glomerular vasculitis on biopsy (2/7, 29%) or in the urinary sediment (0/7, 0%). The remaining 9 patients had microscopic polyarteritis but medium vessel involvement was not excluded by angiography. All patients with microscopic polyarteritis and medium vessel involvement had glomerular hematuria (> 100,000 glomerular RBC/ml), proteinuria > 0.5 g/24 hours), and an elevated serum creatinine (0.166 to 0.811 mmol/l). Other symptoms included fever (6/7, 86%), night sweats (5/7, 71%), gastrointestinal bleeding (4/7, 57%), proximal myopathy (3/7, 43%) and peripheral neuropathy (3/7, 43%). One patient (1/7, 14%) had hypertension. Anemia (6/7, 86%), a raised ESR (6/7, 86%), thrombocytosis (6/7, 86%), hypoalbuminemia (6/7, 86%) and abnormal liver function tests (6/7, 86%) were common. Two patients (29%) had an eosinophilia. All 5 individuals who were tested for ANCA were positive (2cANCA, 2pANCA and one pattern not described). In contrast, in patients with polyarteritis nodosa and medium vessel involvement alone, an elevated ESR was common (4/5, 80%) but fever (1/5, 20%), night sweats (0/5, 0%), proximal myopathy (1/5, 20%) and peripheral neuropathy (1/5, 20%) were seen infrequently; hypertension (1/5, 20%) and eosinophilia (1/5, 20%) were also uncommon; and ANCA were not demonstrated (0/3, 0%). Medium-sized vessel involvement is common in patients with microscopic polyarteristis, and these patients are more likely to have renal involvement and systemic symptoms, and be ANCA-positive, than patients with polyarteritis nodosa alone. Gastrointestinal symptoms are often seen in both groups.

Adult↗
PubMed1997

A report of an investigation of end-of-life care practices in health care facilities and the influences on those practices.

In 1992, 82.2% of deaths in Alberta occurred in acute care hospitals or continuing care facilities. This paper outlines the end-of-life care of adult inpatients who died that year in four such facilities (n = 137). CPR was an infrequent end-of-life treatment modality (2.9%), in stark contrast to the extensive use of other medical technologies. Almost every inpatient (94.2%) died with one or more technologies in continuous operation. Although reasons were infrequently given, the desire to promote patient comfort was the most frequent influence on end-of-life technology use. The findings of this study raise issues for debate and further investigation. Chief among these issues is whether or not medical technologies promote comfort during the dying process.

Adult↗
PubMed1996

Apoptosis of Fashigh CD4+ synovial T cells by borrelia-reactive Fas-ligand(high) gamma delta T cells in Lyme arthritis.

The function of the minor subset of T lymphocytes bearing the gamma delta T cell antigen receptor is uncertain. Although some gamma delta T cells react to microbial products, responsiveness has only rarely been demonstrated toward a bacterial antigen from a naturally occurring human infection. Synovial fluid lymphocytes from patients with Lyme arthritis contain a large proportion of gamma delta cells that proliferate in response to the causative spirochete, Borrelia burgdorferi. Furthermore, synovial gamma delta T cell clones express elevated and sustained levels of the ligand for Fas (APO-1, CD95) compared to alpha beta T cells, and induce apoptosis of Fashigh CD4+ synovial lymphocytes. The findings suggest that gamma delta T cells contribute to defense in human infections, as well as manifest an immunoregulatory function at inflammatory sites by a Fas-dependent process.

Apoptosis↗
PubMed1996

General practitioners' opinions of continence care training.

AIMS: To examine general practitioners' confidence in the diagnosis and management of urinary incontinence, to define their unmet continence training and educational needs, and to evaluate the current provision of continence care in general practice, including the role of practice nurses. METHODS: A pre-tested postal questionnaire was sent to 600 general practitioners throughout New Zealand to obtain information about their demography and training in incontinence management, their confidence in diagnosis and treatment, and their perceptions of met and unmet educational needs in continence care. They were also asked about current provision of continence promotion in their practice and their views on the role of practice nurses in caring for incontinent patients. Confidence data were recorded on five point scales and analysed using chi square tests. Cluster analysis was used to describe groups with different opinions on practice nurses' roles. RESULTS: The response rate from eligible contacts was 81.3%. Although most respondents provide continence care, only 2.6% offered special clinics for continence promotion. Fewer than half felt confident to diagnose the causes of incontinence. Confidence in managing incontinence in children was consistently lower than for other incontinence presentations. There was no difference by sex in confidence in caring for incontinent patients although female respondents were more likely to consider management of continence care part of a practice nurse's role (chi 2 = 47.5, p < 0.01) and to routinely ask well women about incontinence (chi 2 = 243.6, p < 0.01). Most respondents (71.9%) could not remember having had any formal training in the management of incontinence at either undergraduate or postgraduate level. Recall of postgraduate education was associated with greater levels of confidence in management of continence problems. There was general agreement that it was appropriate to include training in continence management in vocational and continuing medical education. CONCLUSION: A substantial proportion of general practitioners perceive a lack of adequate medical training in incontinence care at both undergraduate and postgraduate levels. There is a need for improved education for both general practitioners and practice nurses.

Adult↗
PubMed1996

Autoantibodies and target antigens in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides.

In this study of antineutrophil cytoplasmic antibody (ANCA)-associated diseases, we determined the prevalence of other autoantibodies and the antigen specificities of ANCA. ANA were common, occurring in 7 of 36 (19%) patients with Wegener's granulomatosis, in 16 of 34 (47%) patients with microscopic polyarteritis, in 6 of 11 (55%) patients with segmental necrotising glomerulonephritis and in 8 of 18 (44%) of those with ANCA-associated systemic vasculitis without renal involvement. ANA were associated more often with pANCA and microscopic polyarteritis than with cANCA (P < 0.05). Patterns were speckled (n = 23), homogeneous (n = 10) or nucleolar (n = 4). Anticardiolipin antibodies were also common, occurring in 10 of 25 (40%) patients with Wegener's granulomatosis, in 8 of 14 (57%) patients with microscopic polyarteritis and in 6 of 18 (33%) of those with a systemic vasculitis. However, anticardiolipin antibodies did not correlate with the presence of ANCA in any of the disease groups. Anti-GBM antibodies were demonstrated in only 2 of 25 (8%) patients with Wegener's granulomatosis, in 1 patient with microscopic polyarteritis (1/14, 7%) and in 1 with segmental necrotising glomerulonephritis (1/11, 9%). All four patients with anti-GBM antibodies had either cANCA or pANCA. In the second part of the study, the target antigens of ANCA were determined in Wegener's granulomatosis, microscopic polyarteritis, systemic vasculitis, inflammatory bowel disease, rheumatoid arthritis and systemic lupus erythematosus (SLE). Of the 19 sera with cANCA, 13 (68%) were directed against proteinase 3; other antigens were myeloperoxidase (1/19, 5%), elastase and lactoferrin together (1/19, 5%), lysozyme (1/19, 5%) or unknown (3/19, 16%). Of the 12 (58%) sera from patients with Wegener's granulomatosis who had cANCA, 7 bound to proteinase 3. Antimyeloperoxidase antibodies were present in 14 of 45 (31%) sera with pANCA; other antigens were proteinase 3 (5/45, 11%), elastase (3/45, 78%), lactoferrin (1/45, 2%), cathepsin G (5/45, 11%) or unknown (17/45, 38%). Antimyeloperoxidase antibodies were common in microscopic polyarteritis (6/14, 43%) and systemic vasculitis (5/16, 31%). However, the majority of target antigens in systemic vasculitis and rheumatoid arthritis with pANCA were not determined. "Atypical" ANCA were present in four patients, one with inflammatory bowel disease (1/8, 13%) and three with SLE (3/15, 20%). The specificities were cathepsin G, cathepsin G plus lactoferrin, or unknown in two sera. A recent report has suggested that bactericidal/permeability-increasing protein may be the target in patients with inflammatory bowel disease.

Antibodies, Anticardiolipin↗
PubMed1996

In vivo binding of [11C]SKF 75670 and [11C]SKF 82957 in rat brain: two dopamine D-1 receptor agonist ligands.

The high affinity benzazepine D1 agonists SKF 75670 and SKF 82957 labeled with C-11 were evaluated in vivo in rats as potential radioligands for imaging dopamine D1 receptors with positron emission tomography (PET). Their in vivo pharmacological profile revealed selective binding for both tracers in rat brain regions rich in D1 receptors such as the caudate-putamen. The more lipophilic [11C]SKF 82957 (6-chloro-[11C]SKF 75670) showed a higher brain uptake (more than 2-fold up to 30 min), higher specific uptake in the striatum and higher signal-to-noise ratio (striatum-to-cerebellum = 3.2 +/- 0.4 for [11C]SKF 75670 and 9.7 +/- 2.5 for [11C]SKF 82957 at 60 min post-injection) as compared to [11C]SKF 75670. Both radiotracers exhibited high specificity and selectivity for D1 receptors, since only D1 competitors but not the D2 antagonist sulpiride or the 5-HT2 antagonist ritanserin reduced significantly their binding the striatum with [11C]SKF 75670 or the striatum and olfactory tubercles with [11C]SKF 82957. Previous reports have shown that only D1 agonists can recognize the functional high-affinity state from the low-affinity state of D1 receptors. [11C]SKF 75670 and especially [11C]SKF 82957 are D1 agonist radioligands that can potentially be used to study in vivo the functional high-affinity state of D1 receptors using PET.

Animals↗
PubMed1996

Dry sex in Zimbabwe and implications for condom use.

'Dry sex' refers to the preference for a dry, tight vagina during sexual intercourse. Women in Zimbabwe and elsewhere have been found to use a variety of drying agents to achieve these effects. Previous studies of 'dry sex' have concentrated on documentation of the practice and investigation of any associated increased risk of HIV. In contrast, this study examines the impact of 'dry sex' on condom use and effectiveness. Focus group interviews were held with female HIV/AIDS peer educators in Zimbabwe who had a history of commercial sex work. Participants reported that drying agents had physical and psychological consequences. That is, agents were said to dry and tighten a woman's vagina, and also to serve as 'love potions' to attract sexual partners and ensure their faithfulness. Although vaginal dryness was not found to deter the use of condoms, some women were reluctant to use condoms for fear of blocking the 'magic' of drying agents. There was agreement among participants that condoms frequently broke when used in conjunction with drying agents. Participants primarily attributed condom breakage to excessive vaginal tightness. Lubricants were not routinely used during sex or with condoms. However, participants preferred the use of lubricated condoms when they used condoms. Implications of the 'dry sex' practice for AIDS prevention programs and development of new HIV prevention technologies are discussed.

Adult↗
PubMed1996

Demonstration of the catalytic roles and evidence for the physical association of type I fatty acid synthases and a polyketide synthase in the biosynthesis of aflatoxin B1.

BACKGROUND: Aflatoxin B1 (compound 5. ) is a potent environmental carcinogen produced by certain Aspergillus species. Its first stable biosynthetic precursor is the anthraquinone norsolorinic acid (compound 3. ), which accumulates in the Aspergillus mutant strain NOR-1. Biochemical and genetic evidence suggest that this metabolite is synthesized in vivo by a specialized pair of fatty acid synthases (FAS-1 and FAS-2) and a separately transcribed polyketide synthase (PKS-A). RESULTS: The N-acetylcysteamine (NAC) thioester of hexanoic acid was shown to efficiently support the biosynthesis of norsolorinic acid (compound 3. ) in the NOR-1 strain. In contrast, the mutants Dis-1 and Dis-2, which are derived from NOR-1 by insertional inactivation of fas-1, produced unexpectedly low amounts of norsolorinic acid in the presence of hexanoylNAC. Controls eliminated defects in the parent strain or enhancement of degradative beta-oxidation activity as an explanation for the low level of production. Southern blots and restriction mapping of Dis-1 and Dis-2 suggested normal levels of expression of the PKS-A and FAS-2 proteins should be observed because the genes encoding these proteins are not physically altered by disruption of fas-1. CONCLUSIONS: The impaired ability of Dis-1 and Dis-2, harboring modified FAS-1 enzymes, to carry out norsolorinic acid synthesis implies the need for FAS-1 (and possibly also FAS-2) to physically associate with the PKS before biosynthesis can begin. The failure of the unaffected PKS alone to be efficiently primed by hexanoylNAC, and the presumed requirement for at least one of the FAS proteins to bind and transfer the C6 unit to the PKS, is in contrast to behavior widely believed to occur for type I PKSs.

Aflatoxin B1↗
PubMed1996

Focused peer-mediated educational programs among female sex workers to reduce sexually transmitted disease and human immunodeficiency virus transmission in Kenya and Zimbabwe.

Peer-mediated education programs in Kenya and Zimbabwe focusing on female sex workers for the control of human immunodeficiency virus (HIV) infection and other sexually transmitted diseases (STDs) have led to increased condom use and increased adoption of other safer sex practices, as well as declines in STD and HIV incidence among female sex workers. It is likely that similar declines have occurred among their clients and possibly in the general community, although supporting data are limited. These results are encouraging. However, progress in increasing the scale and coverage of intervention programs among female sex workers has been slow. Constraints to expanding program coverage include inadequate political commitment; deficiencies in program planning, management, and human resources; and insufficient funding. The challenges currently are to show that behavioral change can be sustained and to scale up activities from small demonstration projects to district, provincial, and national levels.

Catchment Area, Health↗
PubMed1996

Clinical features in two patients with IgA glomerulonephritis and thin-basement-membrane disease.

BACKGROUND: Both IgA glomerulonephritis (IgA gn) and thin basement membrane disease (TBMD) are common forms of glomerulonephritis. Patients with these conditions may present with identical clinical features, but higher urinary RBC counts, heavier proteinuria, and impaired renal function are more common in patients with IgA gn. Because IgA gn and TBMD are common, some patients will have both diseases. SUBJECTS: We describe the clinical features of two individuals with both Iga gn and TBMD, and compare them with the clinical and laboratory characteristics in patients with TBMD (n=15) or IgA gn (n=32) alone. RESULTS: IgA gn was found in two individuals of the 110 with TBMD who were studied. They both had haematuria with >/100 000 RBC/ml and proteinuria >0.2/day (one had more than 1 g/day). These features were more consistent with Iga gn than TBMD alone. However, both individuals had normal serum creatinine and creatinine clearance at presentation. Additional clinical features were macroscopic haematuria in one and hypertension in both. CONCLUSIONS: IgA deposits are not uncommon in patients with TBMD, and these patients have clinical features that resemble those seen in IgA gn rather than TBMD. Patients with both IgA gn and TBMD do not necessarily have the worse prognosis noted in some patients with Iga gn.

Basement Membrane↗
PubMed1996

Beta-carotene in HIV infection: an extended evaluation.

OBJECTIVE: Several small short-term intervention studies have suggested that beta-carotene supplementation in HIV-infected patients can increase the number of various immune cells including CD4 cells. This prospective double-blinded study was designed to investigate whether beta-carotene supplementation would result in this immuno-enhancement in a larger number of patients over a longer time period. METHODS: HIV-positive patients were randomly assigned to receive either 60 mg beta-carotene orally three times daily or a matched placebo. In addition, all patients received a multivitamin supplement. Patients were evaluated at baseline, 1 month, and 3 months for T-cell quantitative subsets, natural killer cells, HIV p24 antigen, beta-carotene levels, complete blood counts and chemistry batteries. Body weights and Karnofsky scores were evaluated at each visit. RESULTS: Seventy-two patients signed informed consent forms and entered the study. Except for serum beta-carotene concentration, there were no statistically significant differences (P < 0.05) between the treatment (60 mg beta-carotene three times daily and multivitamins) and placebo (placebo and multivitamins) groups at baseline or after either 1 or 3 months of treatment. DISCUSSION: Earlier studies suggesting that beta-carotene supplementation increased levels of immune cells in HIV-infected patients were not replicated in this study. The addition of a multivitamin supplement to both arms of this study may have masked any difference between the two groups. However, on the basis of the results of this study, we would not recommend supplementation with high doses of beta-carotene for HIV-infected patients.

Administration, Oral↗
PubMed1996

A capitation primer for pediatricians.

This paper discusses the basic issues involved in capitation contracting for pediatricians. We provide a blueprint for analyzing capitation arrangements. We begin by reviewing the basic concepts of capitation. We then discuss contract features, underwriting and pricing risks, administration, risk assessment and management, and finally quality of care considerations.

Capitation Fee↗