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Biomedical subjects

L J Davis

Publications and source records attributed to L J Davis.

At least 19 recordsLinked to original sources
PubMed2002

Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period.

BACKGROUND: Venous thromboembolic disease (TED), although very rare, is a major cause of maternal mortality and morbidity, hence methods of prophylaxis are often used for women at risk. This may include women delivered by caesarean section, those with a personal or family history of TED and women with inherited or acquired thrombophilias (conditions that predispose people to thrombosis). Many methods of prophylaxis carry a risk of side effects, and as the risk of thromboembolic disease is low, it is possible that the benefits of thromboprophylaxis may be outweighed by harm. Current guidelines for clinical practice are based on expert opinion only, rather than high quality evidence from randomised trials. OBJECTIVES: To determine the effects of thromboprophylaxis in association with pregnancy in women who are pregnant or have recently delivered on the incidence of venous thromboembolic disease and side effects. SEARCH STRATEGY: The register of trials maintained by the Cochrane Pregnancy and Childbirth Group, the Cochrane Controlled Trials Register, MEDLINE, EMBASE and bibliographies of reviews. Date of last search: January 2002. SELECTION CRITERIA: Randomised trials comparing one method of thromboprophylaxis with placebo or no treatment, and randomised trials comparing two (or more) methods of thromboprophylaxis. DATA COLLECTION AND ANALYSIS: Data were extracted independently by all reviewers. Discrepancies were resolved by discussion. MAIN RESULTS: Eight trials involving 649 women were included. Four of them compared methods of antenatal prophylaxis; low molecular weight versus unfractionated heparin (two studies), aspirin plus heparin versus aspirin alone (one study), and unfractionated heparin versus no treatment (one study). Four studies assessed postnatal prophylaxis after caesarean section; one compared hydroxyethyl starch with unfractionated heparin, two compared heparin with placebo (one low molecular weight heparin, one unfractionated heparin) and the other compared unfractionated heparin with low molecular weight heparin. It was not possible to assess the effects of any of these interventions on most outcomes, especially rare outcomes such as death, thromboembolic disease and osteoporosis, because of small sample sizes and the small number of trials making the same comparisons. REVIEWER'S CONCLUSIONS: There is insufficient evidence on which to base recommendations for thromboprophylaxis during pregnancy and the early postnatal period. Large scale randomised trials of currently-used interventions should be conducted.

Female↗
PubMed2002

Economic implications of assisted reproductive techniques: a systematic review.

BACKGROUND: Approximately one in six couples experiences problems with their fertility at some point in their reproductive lives. The economic implications of the use of assisted reproductive techniques require consideration. Herein, the health economics research in this area are critically appraised. METHODS: Multiple strategies were used to identify relevant studies. Each title and abstract was independently reviewed by two members of the study team and categorized according to perceived relevance. The selected papers were then assessed for quality and data were extracted, converted to UK pounds sterling at 1999/2000 prices, tabulated and critically appraised. RESULTS: A total of 2547 papers was identified through the searches; this resulted in 30 economic evaluations, 22 cost studies and five economic benefit studies that met the selection criteria. The quality of these studies was mixed; many failed to disaggregate costs, discount future costs or conduct sensitivity analyses. Consistent findings included the following: initiating treatment with intrauterine insemination appeared to be more cost-effective than IVF; vasectomy reversal appeared to be more cost-effective than ICSI; factors associated with poor prognosis decreased the cost-effectiveness of interventions. CONCLUSIONS: The cost-effectiveness of different interventions should be considered when making decisions about treatment. Future economic appraisals of assisted reproductive techniques would benefit from more robust methodology than is evident in much of the published literature to date.

Adult↗
PubMed2001

Repeatability of subjective refraction in myopic and keratoconic subjects: results of vector analysis.

This paper evaluates the repeatability of refraction in keratoconus patients and normal myopes, using representations of spherocylindrical power that are theoretically valid. Data consist of test-retest refraction data from the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study and similar data from normal myopes. Dioptric powers are transformed to an orthogonal vector representation of dioptric power. The metric of change is the dioptric difference between test and retest. The median difference between test and retest in keratoconus patients is four to six times larger than in normal myopes. Refraction over a rigid contact lens on a keratoconic cornea improves repeatability but remains approximately twice as large as in normal myopes. The methods demonstrated here possess advantages over previous methods and provide a more valid comparison between test and retest and between different subject groups. The repeatability of refraction in keratoconus patients is substantially worse than in normal myopes.

Adult↗
PubMed2001

Point prevalence of alcoholism in hospitalized patients: continuing challenges of detection, assessment, and diagnosis.

OBJECTIVE: To measure a 1-day point prevalence of alcohol dependence among hospitalized patients and to assess practices of detection, evaluation, and diagnosis of alcohol problems. PATIENTS AND METHODS: On April 27, 1994, a total of 795 adult inpatients at 2 midwestern teaching hospitals were asked to complete a survey that included the Self-administered Alcoholism Screening Test (SAAST). The records of SAAST-positive patients were reviewed to determine the numbers of patients receiving laboratory screening for alcoholism, addiction consultative services, and a discharge diagnosis of alcoholism. RESULTS: The survey response rate was 84% (667/795). Of the 569 patients who provided SAAST information, 42 (7.4%) had a positive SAAST score and thus were identified as alcohol dependent. Thirteen (31%) of the 42 alcoholic patients received addiction or psychiatric consultative services during their hospitalization. Serum gamma-glutamyltransferase was measured in 4 (11%) of the 38 actively drinking alcoholic patients. Three (7%) of 42 alcoholic patients received a discharge diagnosis of alcohol abuse or dependence. CONCLUSIONS: The alcoholism prevalence rate was lower than those observed in several other US hospitals. Laboratory testing may be underutilized in identifying hospitalized patients who may be addicted to alcohol. Physician use of consultative services and diagnosis of alcohol dependence had not improved from similar observations more than 20 years earlier. These findings may indicate persistent problems in physician detection, assessment, and diagnosis of alcoholism.

Adult↗
PubMed2000

Development of a binding assay for p53/HDM2 by using homogeneous time-resolved fluorescence.

The p53 tumor suppressor protein is activated and stabilized in response to DNA damage, resulting in cell cycle arrest or apoptosis. HMD2 is a negative regulator of p53. Binding of p53 by HDM2 traffics p53 from the nucleus to the cytoplasm where it is recognized and targeted for ubiquitin-mediated degradation (D. A. Freedman, L. Wu, and A. J. Levine, 1999, Cell. Mol. Life Sci. 55, 96-107). Several reports have suggested that disruption of this complex in normal cells results in p53 signaling (V. Böttger, A. Böttger, A. Sparks, W.-L. Liu, S. F. Howard, and D. P. Lane, 1997, Curr. Biol. 7, 860-869; C. Wasylyk, R. Salvi, M. Argentini, C. Dureuil, I. Delumeau, J. Abecassis, L. Debussche, and B. Wasylyk, 1999, Oncogene 18, 1921-1934). A homogeneous time-resolved fluorescence (HTRF) assay has been developed to monitor p53/HDM2 binding. This assay employs a site-specific biotinylated p53 protein, a GST-fused HDM2 protein, and two fluorophore-conjugated detection reagents, streptavidin-XL665 and europium cryptate-labeled anti-GST antibody ¿Eu(K)-anti-GST. Binding of p53 to HDM2 brings the fluorophores into close proximity, allowing fluorescence resonance energy transfer to occur. Development of this assay and comparison to a traditional ELISA are described in this report. The HTRF assay was then utilized to assess the effect of serine phosphorylation within the p53 N-terminus on HDM2 binding, and to determine the relative affinity of a p73 peptide for HDM2.

Amino Acid Sequence↗
PubMed2000

Increased plasma levels of interleukin-1, interleukin-6 and alpha-1-antichymotrypsin in patients with Alzheimer's disease: peripheral inflammation or signals from the brain?

Plasma concentrations of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), C reactive protein (CRP) and alpha-1-antichymotrypsin (ACT) in 145 patients with probable Alzheimer's disease (AD) and 51 non-demented controls were measured. To investigate the cellular activation of peripheral immune system, plasma levels of neopterin were also investigated. Plasma levels of IL-1 were detectable in 17 patients with AD (13%) and only in one control (2%) and average levels of IL-1 were higher in AD patients than in controls (p < 0.001). IL-6 plasma levels were detectable in a higher proportion of AD and controls (53% and 27%, respectively), and were increased in patients with AD (p < 0.001). Plasma levels of ACT were increased in patients with AD (p < 0.001) and CRP levels were in the normal range. Plasma levels of neopterin were slightly lower in AD patients than in controls, but differences were not statistically significant. No significant correlation was observed between IL-1 and IL-6 levels or neopterin and cytokine levels in plasma from AD patients. Plasma levels of ACT negatively correlated with cognitive performances, as assessed by the mini mental state examination (MMSE; R = -0.26, p < 0.02) and positively correlated with the global deterioration state (GDS) of AD patients (R = 0.30, p < 0.007). Present findings suggested that detectable levels of circulating cytokines and increased ACT might not be derived by activation of peripheral immune system of AD patients. Detection of these molecules might be used for monitoring the progression of brain inflammation associated with AD.

Aged↗
PubMed1999

Teleoncology in the Department of Defense: a tale of two systems.

Two telemedicine networks were developed for the purpose of conducting multidisciplinary oncology ("teleoncology") conferences. The infrastructure of each system differed: one system was Internet-based; the other was delivered via Integrated Services Digital Network (ISDN) lines. The purpose of this study was to describe the infrastructure and cost, consultative process, technical aspects, and conference format of the two teleoncology programs. The two systems' technical aspects, participant satisfaction with the systems, and conference participation were compared qualitatively. Assessment of the technical aspects of the systems suggested that each had distinct advantages. Survey results indicated that provider satisfaction with the technical and logistical aspects of each type of teleoncology conference was high. The present study may prove helpful for individuals who are considering implementing their own teleoncology programs.

Government Agencies↗
PubMed1999

Military women's research.

Until 1994, there was a paucity of research aimed at the female soldier. With the dramatic increase in the numbers of military women and their subsequent assumption of expanded roles, it is vital that increased research emphasis be exerted toward this group. A 1994 Congressional directive mandated that women be included in all Department of Defense-sponsored research. This led to the establishment of the Defense Women's Health Research Center for "multidisciplinary and multi-institutional research" on military women's health issues. This article presents demographic data of military women along with descriptions of current research endeavors and issues in need of continued and future research.

Academies and Institutes↗
PubMed1998

Prostaglandin E2 induced polymerization of human alpha-1-antichymotrypsin and suppressed its protease inhibitory activity: implications for Alzheimer's disease.

Different molecular forms of alpha-1-antichymotrypsin (ACT) in sera and cerebrospinal fluids from patients with Alzheimer's disease (AD) were detected. Monomeric and polymeric ACT were observed by polyacrylamide gel electrophoresis of both sera and cerebrospinal fluids. ACT polymers were increased in AD patients with the apolipoprotein E (APOE) 4 allele. Increased levels of inactive ACT molecules were also detected in brain homogenates of patients with the APOE 4 allele. Experimental conditions promoting in vitro polymerization of ACT and the effect of polymerization on the biological activity of this serpin were also explored. Incubation of this serpin with prostaglandins of E series (PGE 2) induced ACT polymerization and decreased its activity. Amyloid beta-peptide1-42 did not significantly affected the biological activity of ACT. Inactivation of protease inhibitors by inflammatory molecules such as PGE 2 released from activated microglia in AD brains may promote amyloid deposition and neurodegeneration.

Alzheimer Disease↗
PubMed1998

Gender differences in factor structure of the Self-Administered Alcoholism Screening Test.

Recent studies have revealed differences between men and women alcoholics in symptoms, consequences, and help-seeking behavior related to alcohol usage. Based on these findings, it was hypothesized that gender differences also would appear on alcohol screening instruments. The Self-Administered Alcoholism Screening Test (Colligan, Davis, & Morse, 1988: SAAST: Swenson & Morse, 1975) of 1,920 men and 1,775 women was subjected to a within-gender, principle-components, factor analysis with a varimax rotation. Gender differences at the component level were revealed. Men endorsed the "help-seeking for alcohol-related problems" component while women endorsed the "help-seeking for emotional problems" component. In addition, men expressed concern about receiving a psychiatric label while women expressed concern about receiving a drinker label. The results suggest that different items need to be used in screening women for alcohol-related problems.

Adult↗
PubMed1998

A survey of risk factors for cryptosporidiosis in New York City: drinking water and other exposures.

We conducted a survey to determine the prevalence of known and theoretical exposure risks for cryptosporidiosis among selected New York City residents. Subjects were recruited from outpatients attending either a practice for persons with HIV infection (n=160), or other medical practices (n=153), at The New York Hospital-Cornell Medical Center. Despite a greater concern for waterborne infection, 82% of HIV-infected subjects reported consuming municipal tap water compared to 69% of subjects from other medical clinics (OR 2.1, 95% Cl 1.2-3.6, P=0.006). Although 18% and 31% of subjects, respectively, denied any tap water consumption at home or work, all but one from each cohort responded positively to having at least one possible alternate source of tap water ingestion such as using tap water to brush teeth or drinking tap water offered in a restaurant. 78% and 76% of subjects, respectively, had at least one potential risk for exposure other than municipal water consumption, such as swimming in pools or contact with animals. Our findings indicate that it is possible to stratify the population into subsets by the amount of tap water consumed. This suggests that an observational epidemiologic study of the risk of contracting cryptosporidiosis from everyday tap water consumption is feasible.

Adult↗
PubMed1998

Visual acuity repeatability in keratoconus: impact on sample size. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study Group.

PURPOSE: The purpose of this paper is to determine the repeatability of visual acuity measurement in keratoconus and to describe the impact of measurement repeatability on sample size. METHODS: Approximately 10% of a 1209 patient sample in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study were selected randomly for a Repeat CLEK Study Visit. Patients were tested at the 15 CLEK Participating Clinics. The test-retest sample consisted of 1 34 keratoconus patients who met the entry criteria of the CLEK Study. High and low contrast Bailey-Lovie visual acuity was measured with the patient's habitual visual correction (entrance visual acuity monocularly and binocularly), and with the best correction monocularly (either the patient's rigid contact lens and over-refraction, or with a CLEK Study trial lens and appropriate over-refraction) at two visits separated by a median of 90 days (range 22 to 268 days). RESULTS: The mean absolute differences between the number of letters correct at the two visits ranged from a low of 3.24 +/- 3.1 for entrance high contrast binocular acuity to a high of 5.48 +/- 5.1 for best corrected low contrast monocular acuity. Intraclass correlation coefficients ranged from 0.757 to 0.853. The visual acuity score was somewhat higher at the Repeat Visit than at the Baseline Visit when the examiners were different between visits. CONCLUSIONS: Given the variable vision reported by keratoconus patients, visual acuity in this sample was very repeatable. Repeatability was slightly poorer when different examiners tested visual acuity at the Baseline and Repeat Visits.

Adolescent↗
PubMed1998

Complex refractive errors in pediatric patients: cause, management, and criteria for success.

BACKGROUND: Uncorrected refractive error in children is an important contributor to permanent neurological visual impairment (amblyopia). Spectacles are often inadequate for certain refractive errors that occur in the pediatric population. Therefore, the purpose of this paper is to present the diagnostic and therapeutic considerations of infants and children referred to a hospital specialty contact lens practice during a 30-month period. METHODS: A retrospective cohort design was used to study patients 12 years or younger referred to a hospital-based contact lens service and cared for by the author. Sixty patients were first examined during the enrollment period. Follow-up data were collected after a period of no less than 3 years from the initial visit. Success with the prescribed therapy was assessed by comparing the final method of optical correction with that prescribed at the initial presentation. RESULTS: Aphakia and trauma were the two most common causes for referral, representing 57% of the patients younger than age 12. Contact lenses were prescribed for 51 of the 60 patients (85%) at presentation. Seventy-five percent of patients with unilateral aphakia attributable to congenital cataract were wearing a contact lens at the most recent follow-up examination. This was reduced to 60% with aphakia after trauma and just 50% with bilateral aphakia. The frequency of a visual acuity of 20/40 or better was 67% for bilateral aphakia, 47% after trauma with aphakia, and 25% for unilateral aphakia. CONCLUSIONS: The results presented here suggest that patients with unilateral aphakia attributable to congenital cataract have the most consistent contact lens wear, followed by patients with unilateral aphakia attributable to trauma. Patients with bilateral aphakia were more likely to have changed to spectacle lens wear. Patients wearing contact lenses at the most recent follow-up examination were more likely to have good visual acuity.

Aphakia, Postcataract↗
PubMed1998

Repeatability of refraction and corrected visual acuity in keratoconus. The CLEK Study Group. Collaborative Longitudinal Evaluation of Keratoconus.

PURPOSE: The purpose of the test-retest phase of the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study was to determine the repeatability of the various parts of the CLEK Study protocol. This paper presents the test-retest parameters of the refraction protocol. METHODS: We examined 138 CLEK Study-eligible patients on two occasions (median, 90 days; range, 22 to 268 days). All patients underwent subjective refraction on two occasions, and contact lens over-refractions were performed either over the patient's habitual rigid contact lenses or over a trial rigid contact lens equal in base curve to the steep keratometric reading in nonrigid contact lens wearers. RESULTS: Mean interoccasion differences +/- SD were -0.32 +/- 2.91 D and -0.17 +/- 1.39 D for subjective refraction sphere and cylinder power, respectively, and the mean absolute difference for subjective refraction cylinder axis was 18.1 +/- 20.2 degrees. The mean interoccasion difference +/- SD for high-contrast visual acuity with subjective refraction was 0.38 +/- 10.9 letters correct. Mean interoccasion differences +/- SD were -0.11 +/- 0.81 D and 0.02 +/- 0.67 D for contact lens over-refraction sphere and cylinder power, respectively, and the mean absolute difference for contact lens over-refraction cylinder axis was 11.6 +/- 9.9 degrees. The mean interoccasion difference +/- SD for visual acuity with contact lens over-refraction was 0.50 +/- 5.2 letters correct and 0.71 +/- 6.9 letters correct for high- and low-contrast visual acuity, respectively. CONCLUSIONS: The repeatability of subjective refraction in keratoconus patients is good but somewhat lower than that found in nondiseased eyes. Only 36% of our repeat measures of sphere power from subjective refraction fell within 0.50 D of each other, compared with more than 90% in studies of normal eyes.

Adult↗
PubMed1997

Logistic regression.

Logistic regression has probably been underutilized in clinical investigations of personality because of its relatively recent development (dictated by the need for computer programs to obtain maximum likelihood estimates), and the fact that use has been largely confined to the fields of biostatistics, epidemiology, and economics Its use should be given serious consideration when the outcome of interest is dichotomous (or polychotomous) in nature and the predictors of interest may be categorical or continuous. The logit transformation is quite tractable mathematically, and it embodies the notion of threshold, which may have relevance for many of the variables that are of interest to investigators in the field of personality. Furthermore, investigators with experience in multiple linear regression or contingency table analysis should have little trouble in transitioning to logistic regression. Logistic regression programs are readily available in the major statistical packages, all of which provide fairly standard output.

Journal Article↗
PubMed1997

Cyclospora.

Explore the source record for details and available documents.

Animals↗
PubMed1996

Effects of N1-guanyl-1,7-diaminoheptane, an inhibitor of deoxyhypusine synthase, on the growth of tumorigenic cell lines in culture.

N1-guanyl-1,7-diaminoheptane (GC7) is a potent inhibitor of deoxyhypusine synthase (DHS), the enzyme that catalyzes the first step in the hypusination of eukaryotic translation initiation factor 5A (eIF-5A). Since eIF-5A is the only known cellular substrate for DHS and GC7 has been reported to block the proliferation of CHO cells, it has been suggested that DHS may be a novel target for anti-cancer therapy. In the present study we investigated the antiproliferative effect of GC7 on several tumorigenic cell lines under various growth conditions. We found that this compound inhibits the proliferation of H9 cells in suspension culture and the growth of HeLa cells and v-src-transformed NIH3T3 cells under both anchorage-dependent and anchorage-independent conditions. Moreover, studies with NIH3T3 cells and v-src-transformed NIH3T3 cells show that GC7 inhibits the growth of both cell lines in monolayer culture with similar potency and could not reverse the transformed phenotype. In addition, the v-src-transformed cells grown under both anchorage-dependent and anchorage-independent conditions showed similar sensitivity toward GC7. These data indicate that GC7 acts as a general antiproliferative agent and does not appear to preferentially target tumorigenic cell types. Cell cycle analysis show that GC7 reduces the CHO-K1 cell population in the G1-phase of the cell cycle by 42% and increases the number of cells in the S-phase by 44%. This cell cycle distribution profile strikingly resembles the distribution of cells treated with puromycin. This result supports the hypothesis that the synthesis of a subset of proteins important for the S-phase progression of CHO-K1 cells might be dependent upon hypusinated eIF-5A. Thus the antiproliferative effect of GC7 appears to be related to its interference with the progression of cell cycle, which also provides a possible explanation for the lack of selectivity of GC7 between nontransformed and transformed cell types tested in this study.

3T3 Cells↗