Biomedical subjects
C Lewis
Publications and source records attributed to C Lewis.
A cardiovascular health education program for rural schools.
Public understanding of cardiovascular disease (CVD) risk factors and primary prevention has increased, due in part to community prevention efforts. However, many segments of society are difficult to reach. Such groups still need public education to acquire the knowledge that can lead to behavior change. Community intervention programs in rural areas face the challenge of disseminating health information to widely scattered populations isolated by difficult terrain and weather, and restricted by the sparsity of channels for mass communication. School health promotion programs, because of the special role schools play in rural communities, can help reach rural populations. During a five-year period, the Otsego-Schoharie Healthy Heart Program, a state-funded community intervention program, provided presentations to 18% of the combined total population of two rural counties through its school-based component. It also helped promote other program initiatives by establishing linkages in the community. Schools provide an effective channel for health promotion efforts to reach rural populations.
Measurement of serum arabinitol by gas-liquid chromatography: limitations for detection of systemic candida infections.
The measurement of serum arabinitol in the diagnosis of systemic candidosis was evaluated using a gas-liquid chromatography technique in a cohort of at risk patients. The prevalence of seropositivity was low and did not correlate with evidence of infection. This technique is unlikely to achieve acceptance because it does not discriminate between patients with and without infection; it requires specialised equipment and it is expensive.
Discriminant analysis of symptom pattern and serum antibody titres in humidifier related disease.
BACKGROUND: The heterogeneous patterns of symptoms among factory workers exposed to aerosols from contaminated air humidifiers were analysed to assess the association between specific symptoms and the serum IgG antibody response to the humidifier water contaminants, and to test the ability of specific symptoms to predict this antibody response. METHODS: Symptoms from 88 factory workers were surveyed by a doctor administered questionnaire and compared with their serum IgG antibody titres to humidifier water contaminants quantified by enzyme immunoassay. RESULTS: The strength of association between individual symptoms and antibody showed that fever, shivering or chills, influenza-like symptoms, or headache were individually significantly associated with the presence and higher titres of antibody. This was also true for those subjects whose symptoms were most pronounced during the first day of the working week. Within each subject's full symptom profile there were significant associations between the description of chest tightness, breathlessness, and wheeze; between headache and influenza like symptoms; between fever and shivering or chills; and between intermittent onset and general tiredness. Discriminant analysis of the full symptom profiles showed that there was maximum information content in five independent parameters, namely, the descriptions of fever, headache, and chest tightness, the timing of their onset, and the readiness to describe miscellaneous symptoms in addition to those in the questionnaire. On the basis of these criteria 72% of subjects could be classified according to their antibody state. Cluster analysis with these five independent parameters described four symptom clusters: one associated with high median antibody levels, one with low, and two with zero median levels. These were, respectively: (1) fever with headache and chest tightness; (2) either no or few symptoms; (3) chest tightness and headache with intermittent onset; (4) headache and miscellaneous symptoms with intermittent onset. CONCLUSIONS: The association between serum antibody titres and specific symptom patterns may identify different categories of disease which constitute the spectrum known as humidifier related disease, and strengthens the hypothesis that antibody may be involved in the pathogenesis of some components of the disease.
AIDS-related knowledge, perceptions, and behaviors among impoverished minority women.
OBJECTIVES: The aims of this study were to (1) describe AIDS-related knowledge, perceptions, and risky behaviors of impoverished African-American and high- and low-acculturated Latina women; (2) delineate relationships involving high-risk behaviors; and (3) determine whether risky behaviors differ by race and levels of acculturation. METHODS: Survey instruments were administered to 1173 impoverished women of color residing in homeless shelters and drug recovery programs. RESULTS: Differences based on ethnicity and level of acculturation were found in AIDS-related knowledge, perceived risk of acquiring AIDS, and risky behaviors. Low-acculturated Latinas reported low perceived risk and were least likely to engage in illegal drug use and sexual activity with multiple partners. Intravenous drug use was most prevalent among high-acculturated Latinas, whereas nonintravenous drug use and high-risk sexual activity was most prevalent among African-American women. CONCLUSIONS: The data indicate the need for culturally sensitive AIDS prevention programs for women that deal with general issues of drug use and unprotected sex, and that include separate sessions for women of different ethnic backgrounds and acculturation levels to address specialized areas of concern.
The role of helplessness in the response to disease modifying drugs in rheumatoid arthritis.
Fifty patients with rheumatoid arthritis participated in an assessment of their helplessness before and after a 3-month disease modifying drug trial. A multidimensional approach measuring helplessness was used, assessing cognitive, affective, and behavioral components. Both before and after the drug trial, helplessness indices accounted for a highly significant amount of variation in self-reported pain and functional disability. Moreover, Time 1 helplessness predicted greater flare activity after the drug trial. Helplessness indices, however, did not correlate with joint examination measures within time periods, nor did they predict change in these measures over the drug trial. The importance of the role of helplessness in subjective and objective measures of clinical status in persons undergoing drug therapy is discussed.
Improved formulas for the estimation of renal depth in adults.
Commercial techniques are available to calculate effective renal plasma flow (ERPF) or glomerular filtration rate (GFR) based on the percent injected dose in the kidney 1-2 or 2-3 min post-injection; renal depth is estimated by the Tonnesen equations. Since the Tonnesen equations were derived from ultrasound measurements obtained at an oblique angle in sitting patients, we compared the renal depths obtained from the Tonnesen equations with the renal depth measured by computed tomography in supine patients, the most common position for radionuclide renography. The renal depth, height, weight, age and sex were determined for 126 patients undergoing CT scanning. Patients with obvious renal or abdominal pathology were excluded. The Tonnesen equations significantly underestimated renal depth. Using stepwise linear regression analysis, we derived a set of equations based on age, height and weight and applied these prospectively to a new set of 75 patients. In addition, a second set of equations were derived for the new data. There was no difference in the results for the two equations. We then pooled both studies and derived a combined set of equations: right renal depth (mm) = 153.1 weight/height + 0.22 age + 0.77 and left renal depth (mm) = 161.7 weight/height + 0.27 age - 9.4, where weight is in kilograms and height is in centimeters. The correlation coefficients were 0.81 and 0.83 for the right and left kidneys respectively with standard errors of the estimate of 10.2 and 10.1 mm. These equations provide a much better estimate of renal depth in the supine patient than the Tonnesen equations.
Alterations of fluid and electrolyte balance in thoroughbred racehorses following strenuous exercise during training.
Alterations of acid-base status, and fluid and electrolyte balance subsequent to exercise in Thoroughbred racehorses in North America have not been well-characterized. Des-cribed here are the results of an observational study conducted to characterize changes in fluid and electrolytes following strenuous exercise of 16 Thoroughbreds under routine training conditions. Changes following strenuous exercise were determined for the following variables: serum concentrations of sodium (Na), potassium (K), chloride (Cl) and protein; pH of blood; osmolality of plasma and urine; body weight; and, fractional urinary excretion (FE) of Na, K and Cl. The following changes occurred during exercise: increased concentration of Na in blood; increased FE of Na; decreased concentration of Cl in blood; decreased FE of Cl; increased urinary and plasmal osmolality; weight-loss; decreased pH of blood; and, increased concentration of lactic acid. The concurrent decreased concentration of chloride in plasma and acidemia in these horses differed from the hypochloremic, metabolic alkalosis previously described among endurance horses. Acidemia was attributed to production of lactic acid by anaerobic glycolysis.
A maximum confidence approach for measuring progression and regression of coronary artery disease in clinical trials.
BACKGROUND: Imaging trials using arteriography have been shown to be effective alternatives to clinical end point studies of atherosclerotic vascular disease progression and the effect of therapy on it. However, lack of consensus on what end point measures constitute meaningful change presents a problem for quantitative coronary arteriographic (QCA) approaches. Furthermore, standardized approaches to QCA studies have yet to be established. To address these issues, two different arteriographic approaches were compared in a clinical trial, and the degree of concordance between disease change measured by these two approaches and clinical outcomes was assessed. METHODS AND RESULTS: In the Familial Atherosclerosis Treatment Study (FATS) of three different lipid-lowering strategies in 120 patients, disease progression/regression was assessed by two arteriographic approaches: QCA and a semiquantitative visual approach (SQ-VIS). Lesions classified with SQ-VIS as "not," "possibly," or "definitely" changed were measured by QCA to change by 10% stenosis in 0.3%, 11%, and 81% of cases, respectively. The "best" measured value for distinguishing definite from no change was identified as 9.3% stenosis by logistic regression analysis. The primary outcome analysis of the FATS trial, using a continuous variable estimate of percent stenosis change, gave almost the same favorable result whether by QCA or SQ-VIS. CONCLUSIONS: The excellent agreement between these two fundamentally different methods of disease change assessment and the concordance between disease change and clinical outcomes greatly strengthens confidence both in these measurement techniques and in the overall findings of the study. These observations have important implications for the design of clinical trials with arteriographic end points.
Ethical and policy implications for the allocation of health care services to elderly persons in rural America.
Explore the source record for details and available documents.
Comparison of recombinant tissue factor pathway inhibitors expressed in human SK hepatoma, mouse C127, baby hamster kidney, and Chinese hamster ovary cells.
Recombinant tissue factor pathway inhibitor (rTFPI) has been expressed in four mammalian expression systems using human SK hepatoma, mouse C127, baby hamster kidney (BHK), and Chinese hamster ovary (CHO) cells as hosts. On sodium dodecyl sulfate polyacrylamide gel electrophoresis, the immunoaffinity purified rTFPIs all show broad bands and the mean molecular weight of SK hepatoma and C127 rTFPIs (M(r) approximately 38,000) appear larger than those of BHK and CHO rTFPIs (M(r) approximately 35,000). All these proteins inhibit factor Xa and appear to bind factor Xa with 1:1 stoichiometry. The ability of these proteins to inhibit tissue factor-induced coagulation in plasma was examined using a prothrombin time assay. The relative activities of SK rTFPI:C127 rTFPI:BHK rTFPI:CHO rTFPI were found to be 28:15:2.1:1. By Western blot using specific antisera against the amino- and carboxy-termini of TFPI as probes, it is found that all the immunoaffinity purified rTFPIs possess approximately equal amounts of the amino terminus, but the C127 and BHK rTFPIs are deficient in carboxy terminus and the CHO rTFPI is essentially devoid of this region of the protein. Mono S chromatography allowed separation of the full-length and the truncated molecules with high and low anticoagulant activities, respectively. The above results suggest that proteolysis of the carboxy terminus of TFPI occurs to different extent when TFPI is expressed in different cells and that the carboxy terminal region of the TFPI molecule is important for the inhibition of tissue factor-induced coagulation.(ABSTRACT TRUNCATED AT 250 WORDS)
Self-administered patient questionnaire for assessing knowledge about joint arthroplasty prior to surgery.
This article assesses the discriminant validity of a questionnaire designed to test patients' knowledge about total joint arthroplasty prior to preoperative educational intervention. The method employed was to compare responses on the test by surgeons, health care workers, and patients and to evaluate whether the test could discriminate among groups. A total of 148 patients, 59 health care workers and 28 orthopedic surgeons completed the questionnaire. The results show that patients are knowledgeable about the benefits of surgery, but are in need of information about surgical risks and complications. The test was able to discriminate between surgeons and the other two groups, but there were few differences between health care workers and patients. Item analysis also demonstrates that the test is reliable. Although the test exhibits acceptable psychometric properties, a major problem in using this test in evaluating educational interventions is the relatively high average score and the potential ceiling effect that prevents measurement of further gains in knowledge. More work is needed on expanding the test to include more items where knowledge of total joint arthroplasty is limited.
Sources of genotoxicity and cancer risk in ambient air.
Products of incomplete combustion are identified as a major source of carcinogenic risk in urban areas, especially those from small non-industrial sources. The major ubiquitous emission sources outdoors in populated areas are residential home heating and motor vehicles. Indoors the major combustion source is environmental tobacco smoke. Polycyclic organic matter adsorbed onto the particles emitted from incomplete combustion are estimated to make the largest contribution to human genotoxic and cancer risk. Mutagenic emission factors combined with dispersion modelling indicated that automobiles and heating sources were major sources of mutagens. Ambient air studies to apportion the sources of mutagens in non-industrial areas confirmed this prediction. To apportion and estimate the cancer risk of ambient organic matter from particles in vivo animal tumour data, receptor modelling and human exposure data were combined. Tumourigenicity studies of the source apportioned ambient organic matter provided the relative tumour potencies of two ambient samples of different source composition. The human cancer unit risks were developed based on the comparative potency method using tumour data from these ambient samples. Residential wood combustion accounted for 75% of the exposure to particle associated organics, but only 20% of the estimated cancer risk. The remaining 80% of the risk appears to be associated with the mobile source component and atmospheric transformation products from these source emissions.
Behavioral consequences of illness: childhood asthma as a model.
Several areas of research on childhood asthma are discussed within a transactional model of asthma. The model emphasizes the multidirectional influences that affect the severity of asthma and associated behavioral disability. The initial focus is on how the clinical presentation and morbidity of asthma are affected both by somatic predisposition and by interactions with multiple internal and external elements. Specific elements include emotional factors, neuroimmunology, temperament, and medication side effects. Second, the impact of asthma on the child, his or her family, and segments of the community are described, as are consequences of the disorder on quality of life. Third, there is a synopsis of preventative interventions for reducing the medical and behavioral impact of childhood asthma. The motif is that the interaction of medical and behavioral procedures can improve the management of asthma while consequences of the disorder are mollified. Finally, as examples of a transactional model of asthma, self-management programs for teaching children to become partners with their physicians in establishing and maintaining control over the disorder are described. A representative of self-management--the ACT (Asthma Care Training) program--is described, along with the impact such programs have on children, their families, and institutions. The conclusion emphasizes that asthma is a complicated and unpredictable disorder that puzzles physicians, behavioral scientists, and patients. Although new treatments may be over the horizon, controlling childhood asthma and its consequences currently rests on the cooperation and increased interaction of medical and behavioral scientists.
Malignant melanoma in inflammatory bowel disease.
Malignant melanoma occurred in 11 patients with inflammatory bowel disease (IBD). Six cases occurred in patients with ileocolitis, two in regional enteritis, one in granulomatous colitis, and two in patients with ulcerative colitis. The mean age at development of IBD was 24 yr, and at development of melanoma was 40 yr: the mean duration from onset of IBD to development of melanoma was thus 16 yr. All patients for whom complete information was available, except two, had received steroids and azulfidine for approximately a decade, as well as blood transfusions, usually multiple, and on repeated occasions. Six of the 11 patients had undergone one to seven prior operations (mean 3.5). All patients had wide radical excision of the melanoma, with or without concomitant or subsequent nodal dissection. Two patients (ages 25 and 36 yr) died rapidly from widely disseminated malignant melanoma. These cases may be coincidental, or else there may be an association between IBD and melanoma, related to immunosuppression either from the disease itself, from the medical and surgical therapy, and/or from x-ray exposure.
Applause for pioneers in cost-benefit research in dietetics.
Explore the source record for details and available documents.
Medium effects in antibody-catalyzed reactions.
Catalytic antibody technology has been used to explore the contribution of medium effects to the overall rate of an enzyme-catalyzed reaction. An antibody generated against a derivative of 2-acetamido-1,5-napthalenedisulfonate efficiently catalyzes the decarboxylation of 5-nitro-3-carboxybenzisoxazole. This unimolecular reaction is not susceptible to general acid-base catalysis but is highly sensitive to microenvironment; thus, it provides a simple chemical model for biologically important decarboxylations. The 10(4)-fold rate acceleration observed for the antibody reflects the kinetic advantage of the low-dielectric environment of the binding pocket acting to destabilize the substrate by desolvation and to stabilize the charge-delocalized transition state through dispersion interactions. These results are pertinent to an understanding of solvent effects in enzymic reactions in general and suggest approaches for developing antibody catalysts for numerous other reactions that involve large changes in charge distribution as the reaction coordinate is traversed.
As Berlin Wall crumbles and two Germanies unite, health care problems emerge.
Explore the source record for details and available documents.