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Biomedical subjects

S R Wilson

Publications and source records attributed to S R Wilson.

At least 55 records · Page 3Linked to original sources

Ethical decision making and patient autonomy: a comparison of physicians and patients in Japan and the United States.

BACKGROUND: Patient-centered decision making, which in the United States is typically considered to be appropriate, may not be universally endorsed, thereby harboring the potential to complicate the care of patients from other cultural backgrounds in potentially unrecognized ways. This study compares the attitudes toward ethical decision making and autonomy issues among academic and community physicians and patients of medical center outpatient clinics in Japan and the United States. METHODS: A questionnaire requesting judgments about seven clinical vignettes was distributed (in English or Japanese) to sample groups of Japanese physicians (n = 400) and patients (n = 65) as well as US physicians (n = 120) and patients (n = 60) that were selected randomly from academic institutions and community settings in Japan (Tokyo and the surrounding area) and the United States (the Stanford/Palo Alto, CA, area). Responses were obtained from 273 Japanese physicians (68%), 58 Japanese patients (89%), 98 US physicians (82%), and 55 US patients (92%). Physician and patient sample groups were compared on individual items, and composite scores were derived from subsets of items relevant to patient autonomy, family authority, and physician authority. RESULTS: A majority of both US physicians and patients, but only a minority of Japanese physicians and patients, agreed that a patient should be informed of an incurable cancer diagnosis before their family is informed and that a terminally ill patient wishing to die immediately should not be ventilated, even if both the doctor and the patient's family want the patient ventilated (Japanese physicians and patients vs US physicians and patients, p < 0.001). A majority of respondents in both Japanese sample groups, but only a minority in both US sample groups, agreed that a patient's family should be informed of an incurable cancer diagnosis before the patient is informed and that the family of an HIV-positive patient should be informed of this disease status despite the patient's opposition to such disclosure (Japanese physicians and patients vs US physicians and patients, p < 0.001). Physicians in both Japan and the United States were less likely than patients in their respective countries to agree with physician assistance in the suicide of a terminally ill patient (Japanese physicians and patients vs US physicians and patients, p < 0.05). Across various clinical scenarios, all four respondent groups accorded greatest authority to the patient, less to the family, and still less to the physician when the views of these persons conflicted. Japanese physicians and patients, however, relied more on family and physician authority and placed less emphasis on patient autonomy than the US physicians and patients sampled. Younger respondents placed less emphasis on family and physician authority. CONCLUSIONS: Family and physician opinions are accorded a larger role in clinical decision making by the Japanese physicians and patients sampled than by those in the United States, although both cultures place a greater emphasis on patient preferences than on the preferences of the family or physician. Our results are consistent with the view that cultural context shapes the relationship of the patient, the physician, and the patient's family in medical decision making. The results emphasize the need for clinicians to be aware of these issues that may affect patient and family responses in different clinical situations, potentially affecting patient satisfaction and compliance with therapy.

Adolescent↗

Synthesis and photophysical properties of steroid-linked porphyrin-fullerene hybrids.

[structure: see text] The photophysical properties of porphyrin-linked fullerene hybrids have generated significant interest, and a number of these hybrids synthesized by this group and others have been extensively characterized with respect to energy and charge-transfer processes that take place upon photoexcitation. Present studies of steroid-linked dyads demonstrate the extent to which through-bond effects operate in these systems.

Journal Article↗

In vivo polysaccharide-specific IgG isotype responses to intact Streptococcus pneumoniae are T cell dependent and require CD40- and B7-ligand interactions.

In vivo Ig responses to soluble, haptenated polysaccharide (PS) Ags are T cell independent and do not require CD40 ligand (CD40L). However, little is known regarding the regulation of in vivo PS-specific Ig responses to intact bacteria. We immunized mice with a nonencapsulated, type 2 Streptococcus pneumoniae (R36A) and compared the parameters that regulated in vivo Ig isotype responses to the bacterial cell wall C-PS determinant, phosphorylcholine (PC), relative to Ig responses to the cell wall protein, pneumococcal surface protein A. Consistent with previous reports using soluble PS and protein Ags, the anti-PC and anti-pneumococcal surface protein A responses differed in that the anti-PC response was induced more rapidly, had a distinctive Ig isotype profile, and failed to demonstrate boosting upon secondary challenge with R36A. However, in contrast to previous studies, the IgG anti-PC response was TCR-alphabeta+ T cell dependent, required CD40L, and was blocked by administration of CTLA4 Ig. The nature of the T cell help for the anti-PC response had distinct features in that it was only partially blocked by CTLA4 Ig and was dependent upon both CD4+ and CD8+ T cells. Surprisingly, whereas the IgM anti-PC response was largely T cell independent, a strong requirement for CD40L was still observed, suggesting the possibility of an in vivo T cell-independent source for CD40L-dependent help. These data suggest that the regulatory parameters that govern in vivo Ig responses to purified, soluble PS Ags may not adequately account for PS-specific Ig responses to intact bacteria.

Animals↗

Crystallographic evidence for the electronic distribution in (2,4-cyclopentadien-1-yl-idenehydrazono)triphenylphosphorane.

The title compound, C23H19N2P, can be graphically represented by several canonical forms. Its crystal structure analysis shows a clear bond alternation in the cyclopentadiene ring, which continues in the azo substructure, indicating that the resonance form containing the nonaromatic neutral cyclopentadienylidene moiety describes the actual hybrid form better than other 'inner ionic' resonance forms containing the aromatic anionic cyclopentadienylic portion. The preference for an s-transoid (E) geometry for the P1-N1-N2-C1 substructure was also confirmed over the other possible s-cisoid (Z) conformer.

Crystallography, X-Ray↗

Modeling linkage and association with evaluation of common sampling schemes.

The probability model of parental transmission (of a multiallelic marker) to affected offspring has been reparameterized in such a way as to distinguish the recombination fraction parameter from the association parameters. The advantage of this reparameterization is that statistical tests can be developed which disentangle linkage and association. It is shown that these tests perform well compared with a standard approach that is commonly used. Further, the simulated data (Problem 2) enable a comparison to be made of the performance of these tests under different family sampling schemes.

Family↗

Testing for HIV: current practices in the academic ED.

The objective of this study was to determine common practices for testing for Human Immunodeficiency Virus (HIV), particularly in patients with other sexually transmitted diseases (STD) in emergency departments (ED) with residency training in Emergency Medicine. Via mail, 112 directors of academic emergency medicine programs in the United States were surveyed. Surveys from 95 academic institutions were completed, returned, and included in the analysis. Three EDs (3%) routinely tested for HIV in patients with suspected STD. HIV testing was performed in the ED in 54% of responding institutions under special circumstances such as employee testing after occupational exposures (54%), cases of rape (46%), and suspicion of HIV infection by clinical manifestations other than suspected STD (36%). Based on the results it was determined that academic EDs do not routinely test for HIV in patients suspected of having a STD and have variable testing practices and policies regarding other possible HIV exposures.

AIDS Serodiagnosis↗

Nongynecologic applications of transvaginal US.

Transvaginal ultrasonography (US) is a noninvasive, readily available imaging technique that has greatly enhanced diagnostic sensitivity and accuracy for both gynecologic and nongynecologic disease. High-frequency US probes placed in the vagina allow high-resolution assessment of all the pelvic viscera, including portions of the gut and urinary tract. In addition, they allow visualization of the peritoneum of the pelvic pouch and the pelvic side walls without interference from bowel gas or adipose tissue. Evaluation of these areas requires a modified US technique that includes the use of the highest-frequency probes with angulation of the transducer to allow assessment of the region of interest. In women of childbearing age, the similarity of symptoms in gynecologic and gastrointestinal tract disease in particular underscores the potential utility of transvaginal US, which may, for example, help differentiate appendicitis in a pelvic appendix from pelvic inflammatory disease. Transvaginal US may also help determine the correct course of therapy, thereby improving patient management. Other indications for transvaginal US include assessment for pelvic appendicitis and diverticulitis, rectal and perianal complications of Crohn disease, and ureteric and bladder calculi and tumors as well as evaluation of the anal sphincters in women with fecal incontinence. Transvaginal US is also superior to routine US in the detection and characterization of ascites and peritoneal disease. Transvaginal US examination should include the entire pelvic cavity and contents, especially in women at risk for pelvic sepsis or peritoneal disease.

Aged↗

Gas at abdominal US: appearance, relevance, and analysis of artifacts.

PURPOSE: To describe the spectrum of ultrasonographic (US) appearances of intraluminal gas, including two clinically relevant gas artifacts. MATERIALS AND METHODS: Observations were made in patients and reproduced in an animal model, an ex vivo gut preparation, and a tissue-mimicking phantom. Appearances were classified according to a physical model of the interaction between sound and collections of gas. RESULTS: Free bubbles of gas appeared as bright echogenic foci extending artifactually owing to lateral and axial blooming. This causes bubbles that abut the gut wall to enhance the layer one echo, which corresponds to the interface between the mucosa and the luminal contents. Such bubbles can also falsely appear to be within the gut wall itself owing to elevation averaging and thereby cause the artifact pseudo-pneumatosis intestinalis. Isolated groups of small bubbles created a characteristic periodicity and tapering of the distal echo pattern. In the extreme case, in which many such echoes are superimposed, "dirty shadowing" occurs. A contiguous pocket of gas may cause the gut wall to appear artifactually thickened (i.e., pseudo-thickened gut). This was shown to be a form of mirror image artifact. CONCLUSION: Classification of the effects of gas on US images according to their physical characteristics may aid in their interpretation. Appreciating two previously undescribed artifacts, pseudo-pneumatosis intestinalis and pseudo-thickened gut, will improve the usefulness of abdominal US.

Abdomen↗

Transvaginal sonography of the anal sphincter: reliable, or not?

OBJECTIVE: The purpose of this study was to validate the use of transvaginal sonography for anal sphincter evaluation, compare this technique with the more commonly used transanal technique, and explain a publication that suggested that transvaginal sonography is unreliable. SUBJECTS AND METHODS: The study population consisted of 50 women, of whom 44 prospectively underwent transanal and transvaginal sonography. The six remaining patients with surgical confirmation underwent only transvaginal sonography. All images were interpreted by the examining radiologist and then reviewed by a second radiologist who was unaware of the first radiologist's interpretations. Defects in the external and internal anal sphincters, the status of the perineal body, and any perianal collections or fistulas were documented. RESULTS: Twenty-five of the 50 patients showed sphincteric defects. Twenty-two had a defect in the external anal sphincter, of whom 16 had a matching internal anal sphincter defect. Four patients had an isolated internal anal sphincter defect. Surgery in nine of these 22 patients confirmed the defects seen on sonography. The 10th patient who underwent surgery had scar tissue rather than a tear in the external anal sphincter that corresponded with the defect seen on sonography. Defects were identified in all patients presenting with fecal incontinence who had undergone either a primary repair or an anterior sphincteroplasty. Of the 25 patients with intact sphincters on both transvaginal and transanal sonography, four had other significant findings including two perianal abscesses and two T3 rectal carcinomas. In 40 of the 44 patients who were prospectively imaged using both techniques, the sonographic findings were in agreement. Review, performed by a second radiologist who was unaware of the first radiologist's interpretations, verified the findings resulting in an 88.6% interobserver agreement. In all patients, perineal body assessment and assessment of perianal inflammatory disease was more accurate with the transvaginal technique. CONCLUSION: Transvaginal sonography is a reliable method for evaluating the anal sphincter, with an accuracy equivalent to that of the transanal technique. Transvaginal sonography is preferable for evaluation of the perineal body and perianal inflammatory processes.

Adult↗

Antigenicity of fullerenes: antibodies specific for fullerenes and their characteristics.

The recent interest in using Buckminsterfullerene (fullerene) derivatives in biological systems raises the possibility of their assay by immunological procedures. This, in turn, leads to the question of the ability of these unprecedented polygonal structures, made up solely of carbon atoms, to induce the production of specific antibodies. Immunization of mice with a C60 fullerene derivative conjugated to bovine thyroglobulin yielded a population of fullerene-specific antibodies of the IgG isotype, showing that the immune repertoire was diverse enough to recognize and process fullerenes as protein conjugates. The population of antibodies included a subpopulation that crossreacted with a C70 fullerene as determined by immune precipitation and ELISA procedures. These assays were made possible by the synthesis of water-soluble fullerene derivatives, including bovine and rabbit serum albumin conjugates and derivatives of trilysine and pentalysine, all of which were characterized as to the extent of substitution and their UV-Vis spectra. Possible interactions of fullerenes with the combining sites of IgG are discussed based on the physical chemistry of fullerenes and previously described protein-fullerene interactions. They remain to be confirmed by the isolation of mAbs for x-ray crystallographic studies.

Animals↗

Effect of topographical aspect and farm system on the population dynamics of Trichostrongylus larvae on a hill pasture.

The population dynamics of Trichostrongylus colubriformis larvae were compared over two years on contrasting topographical aspects north (warm and dry) and south-facing (cool and moist) hill slopes) on paddocks which form part of the 'non-chemical' and conventional' farm systems at the AgResearch Ballantrae Hill Country Station located in a summer-moist region of New Zealand. Sheep faeces containing 50,000 Trichostrongylus eggs were incubated for 4 days at 25 degrees C and then deposited on each of 36 sub-plots in each of 8 plots in a 2 x 2 factorial design in the summer (summer trial) and again in autumn (autumn trial). Pasture was removed to ground level and larvae extracted from six sub-plots from each plot 2, 4, 6, 8, 11 and 14 weeks after contamination in all trials. Larvae were recovered from two strata, 0-5 cm above the soil surface and > 5 cm above the soil surface. Fewer (p < 0.001) larvae were recovered from herbage (47 vs. 118) and residual faeces (28 vs. 246) from the autumn than from the summer trials. This coincided with more rapid (p < 0.001) faecal disappearance in the autumn trials. In the summer trials, fewer (p < 0.003) larvae were recovered from the herbage (101 vs. 182) and residual faeces (140 vs. 352) from plots on the south than the north facing aspect. In the autumn trials there was a rapid (p < 0.0001) faecal disappearance from the south-facing aspect. In the autumn trials there was a non-significant (p < 0.10) trend for fewer larvae to be recovered from the south-facing aspect (2 vs. 54). This also coincided with more rapid faecal disappearance from the south-facing aspect. There was no effect of farm system on the number of larvae recovered. Despite greater (p < 0.0001) numbers of larvae recovered from the bottom stratum of herbage, the density of larvae (L3/kg DM) tended (p < 0.12) to be higher in the top stratum of herbage. It was concluded that season and aspect have a marked effect on the number of larvae recovered from herbage and that this was inversely related to the rate of faecal disappearance.

Agrochemicals↗

Patterns of reticulate evolution for the classical class I and II HLA loci.

Some alleles of the major histocompatibility complex (MHC) genes have a reticulate pattern of evolution, probably resulting from the exchange of segments by gene conversion or recombination. Here we compare the extent and patterns of reticulate evolution among the classical class I and class II loci of the human MHC using the recently developed compatibility and partition matrix methods. A complex pattern is revealed with substantial differences among loci in the extent and pattern of reticulation. Extremely high levels of reticulation are observed at HLA-B and HLA-DPB1, high levels at HLA-A and HLA-DRB1, moderate levels at HLA-C and HLA-DQB1, and low levels at HLA-DQA1. The reticulate events are concentrated in the exons encoding the highly variable, peptide-binding domains, suggesting that the sequence combinations produced by these events are maintained by natural selection.

Alleles↗

Analysis of Australian Crohn's disease pedigrees refines the localization for susceptibility to inflammatory bowel disease on chromosome 16.

A number of localizations for the putative susceptibility gene(s) have been identified for both Crohn's disease and ulcerative colitis. In a genome wide scan, Hugot et al. (1996) identified a region on chromosome 16 which appeared to be responsible for the inheritance of inflammatory bowel disease in a small proportion of families. Subsequent work has suggested that this localization is important for susceptibility to Crohn's disease rather than ulcerative colitis (Ohmen et al. 1996; Parkes et al. 1996). We investigated the contribution of this localization to the inheritance of inflammatory bowel disease in 54 multiplex Australian families, and confirmed its importance in a significant proportion of Crohn's disease families; we further refined the localization to a region near to D16S409, obtaining a maximum LOD score of 6.3 between D16S409 and D16S753.

Australia↗

Polymorphism of the Pi class glutathione S-transferase in normal populations and cancer patients.

Deficiencies of the glutathione transferase isoenzymes GSTM1-1 and GSTT1-1 have been shown to be risk modifiers in a number of different cancers but there have been no similar studies with GSTP1-1, the only member of the Pi class of glutathione S-transferases expressed in humans. Over-expression of GSTP1-1 in tumours suggests that it may be a significant factor in acquired resistance to certain anticancer drugs. We previously identified a cDNA clone with two amino acid substitutions (I105V, A114V). This clone suggests that the GSTP1 gene is polymorphic and it is possible that the different genotypes may be associated with altered cancer risk or drug resistance. In the present study, we report methods for genotyping individuals at codons 105 and 114 of GSTP1 and demonstrate that these two loci are polymorphic in several different racial groups. We also detected significant linkage disequilibrium between these two loci. To determine if either of the alleles at these two loci were associated with altered cancer susceptibility, we genotyped individuals with colorectal cancer or lung cancer. A total of 131 colorectal and 184 lung cancer patients were compared with 199 control individuals. Overall, there were no significant associations between the GSTP1 polymorphisms and either form of cancer.

Adult↗

Uterine arteriovenous malformations: gray-scale and Doppler US features with MR imaging correlation.

PURPOSE: To describe the gray-scale and color and duplex Doppler ultrasound (US) and the magnetic resonance (MR) imaging features of uterine arteriovenous malformations (AVMs). MATERIALS AND METHODS: Uterine AVMs in 10 patients were retrospectively evaluated. All patients underwent gray-scale US and color and duplex Doppler US. Nine underwent angiography with therapeutic embolization; four, MR imaging. The resistance index (RI), pulsatility index (PI), and peak systolic velocities (PSVs) were evaluated. RESULTS: At gray-scale US, uterine AVMs were nonspecific and manifested as subtle myometrial inhomogeneity, tubular spaces within the myometrium, intramural uterine mass, endometrial mass, or cervical mass or sometimes as prominent parametrial vessels. Color Doppler features were consistent and included intense juxtaposed signals with aliasing and apparent flow reversals. Spectral Doppler US revealed low-resistance flow (RI, 0.25-0.55; PI, 0.3-0.6) and PSVs greater than 96 cm/sec, which suggests arteriovenous shunting. MR imaging showed a bulky uterus, a focal uterine mass, disruption of the junctional zones, serpiginous flow-related signal voids, and prominent parametrial vessels. CONCLUSION: Gray-scale morphology and Doppler US features should allow noninvasive diagnosis of uterine AVMs. Doppler and MR imaging features of uterine AVMs may overlap with other causes of arteriovenous shunting, including abnormal placentation and gestational trophoblastic disease (GTD). These can be differentiated with serum beta human chorionic gonadotropin test results (negative with AVM, positive with GTD).

Adult↗

The Fresno Asthma Project: a model intervention to control asthma in multiethnic, low-income, inner-city communities.

The Fresno Asthma Project targeted the entire low-income, inner-city, multiethnic population of Fresno, California. For 36 months following a 6-month planning phase, continuing education was provided to a high proportion of physicians, pharmacists, nurses/respiratory therapists, emergency medical technicians, school personnel, and allied health professionals involved in asthma care in Fresno, including virtually all those providing care/services to the target population. Small group patient education was made available and provided in age- and culturally appropriate formats to patients/families in clinics, hospitals, and schools. General and ethnic media and a Speakers Bureau were used to raise public awareness of asthma as a serious but controllable health problem. This community intervention model is particularly appropriate to multiethnic communities. It is relatively low cost (total direct costs were $140,000 per year), uses existing educational resources, and appears to have minimized counterproductive competition. Although morbidity and mortality trend data are not yet available to monitor program impact, penetration into the target community has been substantial: community physicians refer patients to asthma classes, asthma educator training is ongoing through the local American Lung Association chapter, hospitals and managed care systems serving low- income/MediCal patients offer asthma classes, and public schools and HeadStart are institutionalizing asthma awareness and self-management classes.

Adult↗

Individual versus group education: is one better?

Individual and small group approaches to delivering patient education have differing potential advantages, and various criteria can be used to determine which is "better". Individualization of education is possible in either delivery format, as is its absence. Limited evidence regarding the relative effectiveness and cost-effectiveness of different delivery modes is available from direct comparison and meta-analyses of studies comparing either of the approaches with no education or the patient's own pre-education status. This evidence supports the conclusions that: (1) both individual and group education can improve patient outcomes, (2) it is not possible to conclude that the two delivery formats are essentially equivalent in effectiveness, and there is some evidence that group education may more effective for some outcomes, and (3) wide variation in effectiveness exists among programs in both delivery formats. A model continuum of asthma education is presented that takes advantage of the respective strengths of individual and group delivery.

Adult↗