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Biomedical subjects

E White

Publications and source records attributed to E White.

At least 109 records · Page 6Linked to original sources
PubMed1998

Different effects of gadolinium on I(KR), I(KS) and I(K1) in guinea-pig isolated ventricular myocytes.

1. Using the whole cell configuration of the patch clamp technique, we studied the potential blocking effects of gadolinium (1 microM to 1 mM) on potassium currents: I(KR), I(KS) and I(K1). The study was performed on guinea-pig isolated ventricular myocytes. 2. The background current, I(K1) was insensitive to Gd3+. Thus, we found that no obvious screening of surface charges was visible with concentrations of Gd3+ up to 100 microM. 3. By use of three different protocols: tail currents fitting, analysis of envelope of tails and electrophysiological dissection, we found that I(KR) was the only component of IK that was sensitive to Gd3+. The sensitivity was apparently different depending on the protocol used. 4. Comparison of the results obtained with the different protocols revealed that the rapid component of I(KR) is more sensitive to Gd3+ than the slow one. 5. Of the different protocols used to distinguish between I(KR) and I(KS), the electrophysiological dissection seems to be the more accurate.

Animals↗
PubMed1998

The aetiology and prevention of peri-operative corneal abrasions.

Corneal abrasion is the most frequent ocular complication to occur during the peri-operative period. This review describes the aetiology of corneal abrasions and evaluates the current methods of prevention. Most abrasions are caused by lagophthalmos (failure of the eyelids to close fully) during general anaesthesia, resulting in corneal drying. General anaesthesia reduces both the production and the stability of tears and therefore increases the incidence of this painful condition. Taping the eyelids closed, soft contact lenses, the instillation of aqueous gels or paraffin-based ointments are all effective in preventing corneal abrasions, but ointments are associated with significant morbidity.

Anesthesia, General↗
PubMed1998

Clinical supervision: insider reports of a private world.

An exploratory study, funded by the Department of Health, London and the Scottish Home and Health Department, Edinburgh, was conducted over an 18-month period to provide an informed view on possible assessment tools that could be used to assess the impact of clinical supervision (CS) in nursing and to report on the CS activities in 23 selected sites in England and Scotland. The study not only examined the utility of several standardized research instruments, to be reported separately, but also explored the experience of a small sub-sample of nurses (n = 34) engaged in CS, as supervisors and supervisees. Interviews were undertaken to help better understand some of the issues involved around the domains of structure, process and outcome. Respondents reported an enthusiasm for the opportunity to talk meaningfully to a trusted colleague about their personal circumstances at work. Such opportunities were particularly welcomed by nurses who wished to reflect upon their own practice with patients, especially when dealing with their clinical conditions which were upsetting, or otherwise challenging, and sometimes harrowing. Substantive and methodological areas of interest for future research are suggested.

Adult↗
PubMed1998

A prospective randomized study to assess the clinical efficacy of gonadotrophins administered subcutaneously and intramuscularly.

The purpose of this study was to compare the clinical efficacy of gonadotrophins administered s.c. or i.m., in a prospective randomized study of women undergoing in-vitro fertilization (IVF) treatment at a tertiary referral centre. In all, 71 patients undergoing a total of 162 IVF treatment cycles were randomized to receive either s.c. (n = 41) or i.m. (n = 30) administration of gonadotrophins. Up to three cycles of IVF were assessed for each patient. The main outcome measures were the number of oocytes retrieved, the total amount of gonadotrophins used, the number of follicles recruited and the cumulative pregnancy and live birth rates. The mean number of oocytes retrieved was 10.5 for each group. The number of days of stimulation was significantly shorter for the s.c. group (11.7 +/- 1.9 days, mean +/- SD) than the i.m. group (12.6 +/- 2.3 days). The cumulative conception and live birth rates after three cycles of treatment were similar between the two groups. Our results suggest that the clinical efficacy of s.c. and i.m. administration of gonadotrophins is comparable. Both routes are well tolerated by patients.

Adult↗
PubMed1998

Exposure measurement in cohort studies: the challenges of prospective data collection.

Cohort study designs have several advantages over case-control studies in terms of exposure measurement. If exposure measurement occurs before disease occurrence, cohort studies are much less prone to differential measurement error. Prospective data collection should also reduce measurement error due to poor recall of past exposures. The primary drawback of cohort studies is the large sample size leading to high data collection costs. Several approaches to reduce such costs have been discussed in this presentation, such as selection of lower cost measurement methods and fully measuring the exposure only on a subsample of the cohort (e.g., nested case-control design). However, other innovative approaches to reduce costs are needed. In addition, study reviewers should also consider that the higher costs are justified in relation to the several benefits of this study design, which include not only less measurement error, but also less susceptibility to selection bias and often the ability to study multiple disease outcomes. Improving the accuracy of exposure measurement is increasingly important for cohort studies as we move on to the study of exposures that are difficult to measure or to those with lower relative risks of disease. In such studies, attenuation of the relative risk by the effects of measurement error can lead to failure to detect an association between exposure and disease. The validity of exposure measurements could be improved by a better understanding of the biologically active agent and etiologically important time period of the exposure-disease relation, and by incorporating these into the measure. Long-term cohort studies which cover the etiologically relevant time period could improve the accuracy of measures of exposures by use of repeated biologic measures or repeated updates of self-reported exposures. Measurement error also can be reduced by judicious choice of a cohort to study and by careful attention to quality control procedures. Continued emphasis on the evaluation and improvement of the measurement properties of instruments used in epidemiologic studies will improve the validity of the results of cohort studies.

Cohort Studies↗
PubMed1998

Retaining and tracking cohort study members.

The only way to ensure that losses to follow-up have not biased study results is to keep all losses to an absolute minimum. Since more complete follow-up leads to the identification of additional disease events, the effort spent in locating cohort members also improves the precision as well as the validity of the study results. This presentation reviewed approaches for maximizing retention and minimizing loss to follow-up, including the importance of communicating the expectations of participation and collecting personal information at baseline, conducting frequent personal and mail contact, and providing incentives for participation. Response rates can be increased by repeated attempts to contact each cohort member using a range of approaches (e.g., telephone, mail, personal contacts) and by other procedures specific to mailed questionnaires, telephone interviews, or in-person visits. Lost participants can be traced by use of the NCOA system and contact with other local, state, and national sources. Finally, for those participants who are unable or unwilling to continue or who cannot be found, proxy interviews and/or use of the National Death Index may provide information on the outcomes of interest and vital status. Additional research evaluating the efficacy of the various approaches to retention and tracking is needed to help investigators learn how to best apply study resources to retain and keep track of the largest possible number of cohort members.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Mycobacterium avium bacilli grow saprozoically in coculture with Acanthamoeba polyphaga and survive within cyst walls.

Protozoans are gaining recognition as environmental hosts for a variety of waterborne pathogens. We compared the growth of Mycobacterium avium, a human pathogen associated with domestic water supplies, in coculture with the free-living amoeba Acanthamoeba polyphaga with the growth of M. avium when it was separated from amoebae by a 0.1-micron-pore-size polycarbonate membrane (in a parachamber). Although viable mycobacteria were observed within amoebal vacuoles, there was no significant difference between bacterial growth in coculture and bacterial growth in the parachamber. This suggests that M. avium is able to grow saprozoically on products secreted by the amoebae. In contrast, Legionella pneumophila, a well-studied intracellular parasite of amoebae, multiplied only in coculture. A comparison of amoebae infected with L. pneumophila and amoebae infected with M. avium by electron microscopy demonstrated that there were striking differences in the locations of the bacteria within amoebal cysts. While L. pneumophila resided within the cysts, M. avium was found within the outer walls of the double-walled cysts of A. polyphaga. These locations may provide a reservoir for the bacteria when environmental conditions become unfavorable.

Acanthamoeba↗
PubMed1998

E1B 19,000-molecular-weight protein interacts with and inhibits CED-4-dependent, FLICE-mediated apoptosis.

Genetic studies of the nematode Caenorhabditis elegans (C. elegans) have identified several important components of the cell death pathway, most notably CED-3, CED-4, and CED-9. CED-4 directly interacts with the Bcl-2 homologue CED-9 (or the mammalian Bcl-2 family member Bcl-xL) and the caspase CED-3 (or the mammalian caspases ICE and FLICE). This trimolecular complex of CED-4, CED-3, and CED-9 is functional in that CED-9 inhibits CED-4 from activating CED-3 and thereby inhibits apoptosis in heterologous systems. The E1B 19,000-molecular weight protein (E1B 19K) is a potent apoptosis inhibitor and the adenovirus homologue of Bcl-2-related apoptosis inhibitors. Since E1B 19K and Bcl-xL have functional similarity, we determined if E1B 19K interacts with CED-4 and regulates CED-4-dependent caspase activation. Binding analysis indicated that E1B 19K interacts with CED-4 in a Saccharomyces cerevisiae two-hybrid assay, in vitro, and in mammalian cell lysates. The subcellular localization pattern of CED-4 was dramatically changed by E1B 19K, supporting the theory of a functional interaction between CED-4 and E1B 19K. Whereas expression of CED-4 alone could not induce cell death, coexpression of CED-4 and FLICE augmented cell death induction by FLICE, which was blocked by expression of E1B 19K. Even though E1B 19K did not prevent FLICE-induced apoptosis, it did inhibit CED-4-dependent, FLICE-mediated apoptosis, which suggested that CED-4 was required for E1B 19K to block FLICE activation. Thus, E1B 19K functions through interacting with CED-4, and presumably a mammalian homologue of CED-4, to inhibit caspase activation and apoptosis.

Adenovirus E1B Proteins↗
PubMed1998

Trends in food label use associated with new nutrition labeling regulations.

OBJECTIVES: This study compared use of food labels before and after implementation of new Food and Drug Administration regulations in 1994. METHODS: Data were obtained by random-digit-dial surveys of Washington State residents in 1993 (n = 1001) and 1996 (n = 1450). RESULTS: After implementation of the new regulations, usual label use increased significantly, by 8.5 percentage points in women and 11.3 percentage points in men. More respondents looked for information on fat content and fewer failed to use labels because they "take too much time" or "are too hard to understand. CONCLUSIONS: Use of food labels and satisfaction with their content have increased, but 70% of adults still want labels to be easier to understand.

Adolescent↗
PubMed1998

Cancer-related behavior of vitamin supplement users.

Epidemiological studies suggest that certain vitamin supplements may reduce the risk of some cancers. However, observational studies can be compromised by confounding, because supplement use is related to other factors that affect cancer risk. The purpose of this paper is to identify cancer-related behaviors that could confound studies of the associations between vitamin supplement use and cancer risk. Data are from a random digit dial survey to monitor cancer risk behavior in adults in Washington State (n = 1449). Unconditional logistic regression was used to examine whether regular supplement users were more likely to practice other cancer-related behaviors than nonusers, after adjustment for age, education, and smoking. Among women, supplement users were more likely to have had a sigmoidoscopy [odds ratio (OR), 2.3; 95% confidence interval (CI), 1.2-4.5], hemoccult (OR, 2.3; CI, 1.5-3.5), or mammogram (OR, 1.5; CI, 1.0-2.1) in the past 2 years. Among men, supplement users were twice as likely to have had a prostate-specific antigen test (OR, 2.2; CI, 1.3-3.7) and to regularly take aspirin (OR, 1.7; CI, 1.1-2.6). Supplement users were statistically significantly more likely to exercise regularly, eat four or more servings of fruits and vegetables per day, follow a low-fat diet pattern, and believe in a connection between diet and cancer. The association was especially strong for fruits and vegetables (women, OR, 1.9; and CI, 1.3-2.6; men, OR, 2.4; CI, 1.6-3.8). Those investigating the benefits and risks of vitamin and mineral supplements need to be aware of the lifestyle characteristics of supplement users to assess the potential for bias in their studies.

Adult↗
PubMed1998

Constipation, laxative use, and colon cancer among middle-aged adults.

We examined the associations of colon cancer with constipation and the use of commercial laxatives in a case-control study among men and women ages 30-62 years. We based this analysis on 424 incident cases of colon cancer, diagnosed in the Seattle metropolitan area between 1985 and 1989, and 414 random-digit-dial controls. Frequent constipation during the 10 years before the reference data (2 years before diagnosis), as defined by "feeling constipated to the point of having to take something," was associated with substantially increased risk of colon cancer. The adjusted relative risk (RR) was 2.0 [95% confidence interval (CI) = 1.2-3.6] for constipation 12-51 times per year, and 4.4(95% CI = 2.1-8.9) for constipation 52 or more times a year. Cumulative lifetime use of commercial laxatives was also associated with increased risk of colon cancer. When constipation and commercial laxative use were adjusted for each other, the association with commercial laxative use disappeared, whereas the association with constipation remained strong. Although constipation has not consistently been associated in past studies with a large increase in risk of colon and rectal cancer combined, these results suggest that frequent constipation may be an important risk factor for colon cancer among middle-aged adults.

Adenocarcinoma↗
PubMed1998

Associations of demographic and health-related characteristics with prostate cancer screening in Washington State.

This report describes associations of demographic and health-related characteristics with use of prostate cancer screening. Data are from a random-digit dial survey of Washington State residents. Analyses are restricted to men ages 40-79 years (n = 332) and examine both digital rectal examination (DRE) and blood tests for prostate-specific antigen (PSA) in the previous 2 years. Results are adjusted to be representative of the state's population. In 1996, 53.6% of men received either DRE, PSA, or both. Among those screened, 42% received DRE alone, 15% PSA alone, and 43% both PSA and DRE, and the percentages of men receiving PSA increased markedly with age (30%, ages 40-49 years; 58%, ages 50-59 years; and 77%, ages 60-79 years). After control for other demographic characteristics, the relative odds for any prostate cancer screening were 5.5 for ages 60-79 versus 40-49 years, 2.4 for 16+ versus < or = 12 years of education, and 4.0 for 2+ versus no physician visits in the previous 2 years (all P < 0.05). Characteristics generally associated with good health, including regular exercise and low fat and high fruit and vegetable intakes, were also significantly associated with prostate cancer screening. In conclusion, in 1996, approximately one-half of the men in Washington State over age 40 years had received prostate cancer screening in the previous 2 years. Few men were screened with PSA alone, and the use of PSA as part of prostate cancer screening increased markedly with age. Because PSA screening increases detection of prostate cancer, epidemiological studies of health behavior and cancer risk must carefully control for screening history to avoid detection bias.

Adult↗
PubMed1998

Measurement error from assessing use of vitamin supplements at one point in time.

Although many epidemiologic studies ask about current use of vitamin supplements, long-term use is usually the exposure of etiologic interest. We conducted a mailed survey to investigate the relation between current and long-term (10-year) supplement use (N = 325 adults). Estimates of current daily intake for supplemental micronutrients were roughly twice that of average daily intake over the past 10 years. Correlations between current intake and long-term intake from supplements alone were 0.77, 0.75, and 0.65 for vitamin C, vitamin E, and calcium, respectively. A measure of supplement use at one point in time incorporates measurement error that will attenuate measures of association.

Aged↗
PubMed1997

The E1B 19K protein associates with lamins in vivo and its proper localization is required for inhibition of apoptosis.

Expression of the E1B 19K protein is required to inhibit apoptosis induced by E1A during adenovirus infection and transformation. E1B 19K is homologous to Bcl-2 in function and the two proteins also share limited amino acid sequence homology. Consequently, the E1B 19K and Bcl-2 proteins bind to and inhibit the cellular death-inducing proteins Bax, Bak and Nbk/Bik. Both E1B 19K and Bcl-2 localize to membranes of the nucleus and the endoplasmic reticulum. In addition to membrane association, and unlike Bcl-2, the E1B 19K protein is found associated with intermediate filament proteins in the cytoplasm and the nuclear lamina and copurifies with the lamins both during infection and transformation. While a membrane targeting domain at the C-terminus of Bcl-2 ensures its proper localization, the mechanism by which the E1B 19K protein localizes is unknown. Not surprisingly, lamin A fragments were cloned from a yeast two-hybrid screen for E1B 19K-interacting proteins. The interaction was demonstrated in yeast and mammalian cells in vivo and in vitro and was unique and specific to E1B 19K, with no interaction evident between Bcl-2 and lamin A. Mutants of lamin A/C which localized inappropriately in the cytoplasm or nucleus but retained E1B 19K binding, interfered with the nuclear envelope and cytoplasmic membrane targeting of the E1B 19K protein. Improper localization impaired the ability of the E1B 19K protein to inhibit apoptosis. Thus, proper localization of the E1B 19K protein is required for its function and the interaction of the E1B 19K protein with lamin A/C may represent a means for nuclear envelope localization.

Adenovirus E1B Proteins↗
PubMed1997

The polyproline region of p53 is required to activate apoptosis but not growth arrest.

p53 is a pivotal regulator of apoptosis but its mechanism of action is obscure. We report that the polyproline (PP) region located between p53's transactivation and DNA binding domains is necessary to induce apoptosis but not cell growth arrest. The PP region was dispensable for DNA binding, inhibition of SAOS-2 tumor cell growth, suppression of E1A + RAS cell transformation, and cell cycle inhibition. A temperature-sensitive dominant inhibitory p53 mutant lacking PP (p53ts deltaPP) retained its ability to cooperate with adenovirus E1A in transformation of primary BRK cells. However, while activation of wt p53 induced apoptosis in E1A + p53ts-transformed cells, activation of p53 deltaPP induced cell cycle arrest but not apoptosis in E1A + p53ts deltaPP-transformed cells. Similarly, PP deletion abolished apoptosis in LoVo colon carcinoma cells, which are killed by wt p53 overexpression. Transactivation was largely unaffected by PP deletion. Significantly, BAX induction was intact, indicating that additional events are required for p53 to induce apoptosis. As a recently described site for familial mutation in at least one breast cancer family, the PP region represents a domain that may be altered in human tumors. We concluded that p53's ability to induce apoptosis is dispensable for inhibiting cell growth and transformation and that the PP region plays a crucial role in apoptotic signaling.

Amino Acid Sequence↗
PubMed1997

The G protein alpha subunit (GP alpha1) is associated with the ER and the plasma membrane in meristematic cells of Arabidopsis and cauliflower.

Towards the elucidation of the cellular function(s) of GP alpha1, we have characterized its subcellular localization using immunofluorescence and cell fractionation. GP alpha1 is not present in nuclei or chloroplasts. It is a membrane-bound protein, and analysis of isolated endoplasmic and plasma membranes indicates a good correlation between GP alpha1 in both the plasma membrane and the ER compartment. Interestingly, these results may suggest more different functions for GP alpha1: it might be involved in transmission of extracellular signals across the plasma membrane and in the cytoplasm, and/or it may also be involved in regulating some aspects of the ER functions or membrane trafficking between both membranes.

Arabidopsis↗
PubMed1997

Change in the use of breast-conserving surgery in western Washington after the 1990 NIH Consensus Development Conference.

OBJECTIVE: To evaluate the use of breast-conserving surgery in western Washington before and after the National Institutes of Health Consensus Development Conference (June 18-21, 1990) during which breast-conserving surgery was recommended for most women with early invasive breast cancer. DESIGN: Survey. SETTING: Population-based cancer registry in the Seattle-Puget Sound (Washington) region. PARTICIPANTS: The survey included 13541 women in whom American Joint Committee on Cancer stage I or II breast cancer was diagnosed between January 1, 1983, and December 31, 1993. MAIN OUTCOME MEASURE: Proportion of participants who underwent breast-conserving surgery. RESULTS: From April 1985, after results of a US randomized controlled trial showing equivalent survival in women undergoing mastectomy or breast-conserving surgery were published, to the time of the Conference, breast-conserving surgery was performed on 44.8% of women with stage I and 25.8% with stage II breast cancer. These percentages increased to 54.9% and 35.2%, respectively, during the post-Conference period. While women with stage II breast cancer were less likely than women with stage I breast cancer to undergo breast-conserving surgery before and after the Conference, trends for age and education were attenuated after the Conference. Differences in the use of breast-conserving surgery observed before the Conference between countries of residence and among hospital types were also reduced after the Conference. CONCLUSIONS: These findings suggest that the Conference recommendations had an effect on the adoption of breast-conserving surgery, particularly among groups who were previously least likely to undergo such surgery. Despite progress toward the Conference recommendation that the majority of women with early invasive breast cancer undergo breast-conserving surgery, the majority of women with stage II breast cancer undergo mastectomy.

Aged↗