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Biomedical subjects

M Clark

Publications and source records attributed to M Clark.

At least 91 records · Page 5Linked to original sources
PubMed1999

Access to health care services among people with disabilities receiving Medicaid.

Few data exist describing Medicaid's success in providing health care services to people with disabilities. The access to care survey from the Medical Expenditures Panel Survey was used to collect access data from 502 individuals with disabilities in central Missouri receiving Medicaid under fee-for-service reimbursement. Nearly all of the respondents had a usual source of care, but two-thirds reported difficulties obtaining a needed health care service. Dental, optometric, and personal assistance services were most difficult to obtain. Provider non-participation, non-coverage of a service, and coverage restrictions were the most frequently cited barriers to obtaining care. Results suggest that people with disabilities have difficulty accessing needed health care services through the Missouri Medicaid fee-for-service system.

Adult↗
PubMed1998

Identification of a form of acyl-CoA:cholesterol acyltransferase specific to liver and intestine in nonhuman primates.

The present study demonstrates that two different forms of the intracellular cholesterol esterification enzyme acyl-CoA:cholesterol acyltransferase (ACAT) are present in the nonhuman primate hepatocyte; one is similar to that originally cloned from human genomic DNA, here termed ACAT1, while a second gene product, termed ACAT2, is reported here. The primate ACAT2 gene product was cloned from an African green monkey liver cDNA library. Sequence analysis of an isolated, full-length clone of ACAT2 cDNA identified an open reading frame encoding a 526-amino acid protein with essentially no sequence similarity to the ACAT1 cDNA over the N-terminal 101 amino acids but with 57% identity predicted over the remaining 425 amino acids. Transfection of the cloned ACAT2 cDNA into two different mammalian cell types resulted in the production of abundant ACAT activity which was sensitive to ACAT inhibitors. Northern blot analysis showed that the ACAT2 mRNA was expressed primarily in liver and intestine in monkeys. In contrast, ACAT1 mRNA was expressed in almost all tissues examined. Topologic predictions from the amino acid sequence of ACAT2 indicates that it has seven trans-membrane domains in a configuration that places the putative active site of the enzyme in the lumen of the endoplasmic reticulum. This orientation of ACAT2 in the endoplasmic reticulum membrane, in addition to its expression only in liver and intestine, suggests that this enzyme may have as a primary function, the secretion of cholesteryl esters into apoB-containing lipoproteins.

Amino Acid Sequence↗
PubMed1998

Gene mapping in zebrafish using single-strand conformation polymorphism analysis.

To exploit fully the power of the zebrafish system as a model for vertebrate development, it will be necessary to develop efficient tools for genomic analysis. In this report we have tested whether single-strand conformation polymorphism analysis (SSCP) can be utilized for gene mapping in zebrafish. Over 100 primer pairs derived from noncoding regions of known genes and partially characterized cDNAs were analyzed, and a polymorphism frequency of approximately 50% was detected in zebrafish strains used for genetic mapping studies. A subset of these polymorphic cDNAs was localized on the zebrafish map. SSCP thus represents an efficient strategy for mapping transcribed sequences with a high resolution in the zebrafish genome, which will facilitate the integration of existing zebrafish framework maps, the generation of a zebrafish EST map, and the application of alternative gene localization strategies such as comparative mapping.

3' Untranslated Regions↗
PubMed1998

Sensitivity of the rat hippocampal GABA(A) receptor alpha 4 subunit to electroshock seizures.

The effects of one and five electroshock seizures on [3H]flunitrazepam binding, diazepam-insensitive (DIS) [3H]Ro 15-4513 binding, and levels of mRNA for GABA(A) receptor alpha1, alpha4, beta3 and gamma2 subunits were examined in rats. No changes in any parameter were observed in the CA1 region of hippocampus or in parietal cortex. However, a single seizure produced a rapid and transient increase of alpha4 mRNA in the dentate gyrus, without altering the expression of the other subunits. The putative alpha4 protein, as measured by DIS [3H]Ro 15-4513 binding, was also elevated in the dentate gyrus by a single shock. Repeated electroshock (48-h intervals) resulted in an enhanced response of the alpha4 subunit to the seizure. Neither one nor five seizures altered [3H]flunitrazepam binding.

Animals↗
PubMed1998

Transposed basilic vein versus polytetrafluorethylene for brachial-axillary arteriovenous fistulas.

BACKGROUND: Both transposed basilic vein (BV) and polytetrafluorethylene (PTFE) upper arm arteriovenous fistulas (AVF) are common angioaccess operations. To evaluate the patency and complication rates after AVF, a concurrent series of patients was reviewed. METHODS: Ninety-eight patients underwent brachial artery to axillary vein AVF: 30 BV and 68 PTFE. The PTFE grafts were performed in the standard fashion, whereas the basilic veins were translocated subcutaneously to the brachial artery. RESULTS: Risk factors were similar between the two groups. Basilic vein AVF had better patency at 24 months (70% BV versus 46% PTFE, P = 0.023). The dialysis access complications were higher in the BV group (20%) versus PTFE (5%), but the PTFE group had a higher infection rate (10%) than BV (0%). CONCLUSIONS: The primary and secondary patency rates were superior in the BV AVFs. The BV AVF preserves the venous outflow tract after AVF thrombosis for a future PTFE AVF operation.

Arteriovenous Shunt, Surgical↗
PubMed1998

Longitudinal changes associated with improvement in chronic fatigue patients.

Tertiary care patients with chronic fatigue were followed for 2.5 years to determine if changes in physical and psychological status were associated with improvements in chronic fatigue, physical functioning, and return to work. Results indicated that improvement in psychological symptoms, DSM-III-R disorders, physical examination signs, and changes in whether the patient continued to meet criteria for chronic fatigue syndrome (CFS) were associated with recovery from fatigue, improved functioning, and return to work. Patients who never met CFS criteria or only met criteria at the initial assessment, reported improved physical functioning. Patients whose psychiatric disorders and physical examination signs were still present at a mean follow-up time of 2.5 years were more likely to have persistent fatigue and work disability. Loss of physical examination signs was a significant independent predictor of improved functioning and return to work. These results suggest that psychiatric status, as well as physical status, are associated with recovery from chronic fatigue.

Adult↗
PubMed1998

MRI measurement of brain tumor response: comparison of visual metric and automatic segmentation.

An automatic magnetic resonance imaging (MRI) multispectral segmentation method and a visual metric are compared for their effectiveness to measure tumor response to therapy. Automatic response measurements are important for multicenter clinical trials. A visual metric such as the product of the largest diameter and the largest perpendicular diameter of the tumor is a standard approach, and is currently used in the Radiation Treatment Oncology Group (RTOG) and the Eastern Cooperative Oncology Group (EGOG) clinical trials. In the standard approach, the tumor response is based on the percentage change in the visual metric and is categorized into cure, partial response, stable disease, or progression. Both visual and automatic methods are applied to six brain tumor cases (gliomas) of varying levels of segmentation difficulty. The analyzed data were serial multispectral MR images, collected using MR contrast enhancement. A fully automatic knowledge guided method (KG) was applied to the MRI multispectral data, while the visual metric was taken from the MRI films using the T1 gadolinium enhanced image, with repeat measurements done by two radiologists and two residents. Tumor measurements from both visual and automatic methods are compared to "ground truth," (GT) i.e., manually segmented tumor. The KG method was found to slightly overestimate tumor volume, but in a consistent manner, and the estimated tumor response compared very well to hand-drawn ground truth with a correlation coefficient of 0.96. In contrast, the visually estimated metric had a large variation between observers, particularly for difficult cases, where the tumor margins are not well delineated. The inter-observer variation for the measurement of the visual metric was only 16%, i.e., observers generally agreed on the lengths of the diameters. However, in 30% of the studied cases no consensus was found for the categorical tumor response measurement, indicating that the categories are very sensitive to variations in the diameter measurements. Moreover, the method failed to correctly identify the response in half of the cases. The data demonstrate that automatic 3D methods are clearly necessary for objective and clinically meaningful assessment of tumor volume in single or multicenter clinical trials.

Adult↗
PubMed1998

Removing the 'estimates and guesses' from practice--evidence based tissue viability.

The development of evidence based tissue viability is reviewed using the prevention and management of pressure sores as a specific example. Although data is limited, pressure sores may be more common at the end of the 1990's than they were fifteen years ago, despite changes in clinical practice. If evidence based tissue viability is to grow and mature, then two key obstacles must be overcome; changes in patient populations must be reflected within prevalence or incidence data (case-mix adjustment) so allowing interpretation of longitudinal changes in the occurrence of sores. Secondly, the efficacy and effectiveness of interventions such as pressure-redistributing beds and mattresses must be identified through rigorous and appropriate methodologies. Only through such steps can clinical skill be blended with research evidence to fully realise evidence based practice.

Beds↗
PubMed1998

Evaluation of the provision of fieldwork training through a rural student unit.

A Rural Student Unit was established as a pilot project to trial a model of rural fieldwork placement provision. The Unit aimed to increase the number of student placements available in rural areas and provide undergraduate students with a positive fieldwork experience. The results indicate that the Unit was successful in overcoming some of the barriers to rural fieldwork, for both students and supervisors, and substantially increased the number of students undertaking fieldwork in this area. The results support the further trialing and expansion of the model.

Attitude of Health Personnel↗
PubMed1998

Mobility after hip fracture predicts health outcomes.

OBJECTIVES: Balance and gait are essential to physical functioning and the performance of activities of daily living. The objective of this study was to determine the predictive value of a balance and gait test on subsequent mortality, morbidity, and healthcare utilization among older hip fracture patients. DESIGN: A prospective study of hip fracture recovery. SETTING: Patients with a new hip fracture admitted from the community to one of eight Baltimore hospitals and followed in their homes for 2 years postfracture. PARTICIPANTS: A total of 306 patients with hip fracture, 65 years of age and older, who completed a gait and balance assessment at 2 months postfracture. MEASUREMENTS: The relationship between gait and balance test performance at 2 months postfracture and mortality, physician visits, rehospitalizations, nursing home placement, and falls up to 24 months postfracture was assessed by Cox proportional hazards and least squares regression. RESULTS: After adjusting for age, sex, race, and comorbidity, the balance score and the summary mobility score predicted mortality. A 17% increase in the risk of mortality was demonstrated for each unit decrease in the balance score (range 0-17), and a 10% increase was demonstrated for each decrease in the summary score (range 0-26). Unsteady balance during immediate standing, turning, sitting down, and rising from a chair were associated significantly with increased mortality. Poor balance, but not poor gait, was associated with an increase in hospitalizations up to 24 months postfracture. Both poor balance and poor gait were associated with nursing home placement, with 20% and 17% increased odds, respectively. Mobility did not predict future physician visits or falls. CONCLUSIONS: These findings demonstrate that balance and gait are predictive of future health outcomes for older hip fracture patients.

Aged↗
PubMed1998

Elder care among Mexican American families.

This exploratory study describes caregiving experiences of elderly family members as perceived by eight Mexican American women caregivers and characterizes the ideas that some Mexican Americans have about elder care. A qualitative approach, using open-ended questions, revealed a cultural picture that reflected a very rich cultural heritage. This picture includes the importance of the family's responsibility to care for its elder members and describes family commitments that reach beyond obligation. It also portrays a complex system of cultural beliefs and values that are based on Mexican American tradition. The themes of reciprocity and point of reckoning emerged as two descriptive characteristics of the Mexican American family in the southwestern United States that form the basis for the restructuring of a woman's responsibilities during middle age. This study indicated that the bicultural lens through which the caregiver views the world may differ markedly from that of the elderly family member.

Aged↗
PubMed1998

Evaluating critical thinking skills in a scenario-based community health course.

This study evaluated the influence of a scenario-based community health course on the ability of senior nursing students (N = 54) to address complex problems seen in the community health setting. In addition, we examined whether students' scores on the Watson-Glaser Critical Thinking Appraisal (WGCTA) questionnaire would differ depending on the size of the educational institution they attended before enrollment in a school of nursing and whether the types of electives (liberal arts or science) previously taken would influence the scores. Sign ficant improvements were seen on the Interpretation and Evaluation subscales and on the total critical thinking score from pretest to posttest for students who completed the course. Also students who completed nursing prerequisites in midsized, 4-year universities (10,000 to 30,000 students) had higher pretest mean scores on the majority of WGCTA subscales than did other students.

Adult↗
PubMed1997

Effect of long-term treatment with salmeterol on asthma control: a double blind, randomised crossover study.

OBJECTIVES: To determine the effect of adding salmeterol 50 micrograms twice daily for six months to current treatment in subjects with asthma who control their inhaled corticosteroid dose according to a management plan. DESIGN: A double blind, randomised crossover study. SETTING: Nottingham. SUBJECTS: 101 subjects with mild or moderate asthma taking at least 200 micrograms twice daily of beclomethasone dipropionate or budesonide. INTERVENTIONS: Salmeterol 50 micrograms twice daily and placebo for six months each, with a one month washout. Subjects adjusted inhaled steroid dose according to guidelines. MAIN OUTCOME MEASURE: Reduction in inhaled steroid use, exacerbations of asthma, and use of oral steroids. RESULTS: Data were available for 87 subjects. When compared with placebo salmeterol treatment was associated with a 17% reduction in inhaled steroid use (95% confidence interval 12% to 22%) with no significant difference in the number of subjects who had an exacerbation (placebo 25%, salmeterol 16%) or use of oral steroids. For secondary end points salmeterol treatment was associated with higher morning and evening peak expiratory flow and forced expiratory volume in one second; a reduction in symptoms, bronchodilator use and airway responsiveness to methacholine; and no effect on serum potassium concentration, 24 hour heart rate, or the final forced expiratory volume in one second achieved during a salbutamol dose-response study. CONCLUSIONS: In subjects who adjusted their inhaled steroid treatment according to guidelines the addition of salmeterol 50 micrograms twice daily was associated with a reduction in inhaled steroid use and improved lung function and symptom control.

Administration, Inhalation↗