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Biomedical subjects

G W Welch

Publications and source records attributed to G W Welch.

At least 19 recordsLinked to original sources
PubMed2001

The effect of chronic digitalization on pump function in systolic heart failure.

BACKGROUND: Short- and intermediate-term use of cardiac glycosides promotes inotropy and improves the ejection fraction in systolic heart failure. AIM: To determine whether chronic digitalization alters left ventricular function and performance. METHODS: Eighty patients with mild-to-moderate systolic heart failure (baseline ejection fraction < or =45%) participated from our institution in a multi-center, chronic, randomized, double-blind study of digitalis vs. placebo. Of the 40 survivors, 38 (20 allocated to the digitalis arm and 18 to the placebo arm) were evaluated at the end of follow-up (mean, 48.4 months). Left ventricular systolic function was assessed by both nuclear ventriculography and echocardiography. The ejection fraction was measured scintigraphically, while the ventricular volumes were computed echocardiographically. RESULTS: The groups did not differ, at baseline or end-of-study, with respect to the ejection fraction and the loading conditions (arterial pressure, ventricular volumes and heart rate) by either intention-to-treat or actual-treatment-received analysis. Over the course of the trial, the digitalis arm exhibited no significant increase in the use of diuretics (18%, P=0.33), in distinction from the placebo group (78%, P=0.004), and a longer stay on study drug among those patients who withdrew from double-blind treatment (28.6 vs. 11.4 months, P=0.01). CONCLUSION: Following chronic use of digitalis for mild-to-moderate heart failure, cross-sectional comparison with a control group from the same inception cohort showed no appreciable difference in systolic function or performance. Thus, the suggested clinical benefit cannot be explained by an inotropic effect.

Aged↗
PubMed2000

The interrelationship between body topology and body composition varies with age among women.

The purpose of this analysis was to evaluate the relationship between age and the size and distribution of the fat and lean tissue compartments in a population-based sample of women. The study population consisted of the 875 women aged 18-94 y in the Iowa Bone Health Study who reported never smoking. Fat mass and lean mass were measured using dual X-ray absorptiometry. Hip and waist circumference and height were measured using standardized protocols. Regression was used to model the associations among age, composition and topology measures. When fat mass was modeled as a function of hip and waist circumference as well as age, age(2) and height, the age x height and age x waist circumference interaction terms remained in the fitted model and collectively accounted for 91% of the variance. In contrast, the quadratic model of age alone accounted for 8% of the observed variance in fat mass. Lean mass was modeled in two segments, with age dichotomized at 58 y. Age alone did not predict lean mass in women <58 y but did predict lean mass in women >/=58 y, with the modeled relationship including interactions with waist circumference and height. These models accounted for 70% of observed variance in lean mass. Age is associated with body composition but explains <10% of variation. When measures of height and circumferences are available, amounts of lean and fat mass are highly predictable. This is particularly important for lean mass because no other surrogate measures exist for lean mass, whereas there are surrogates for fat mass, including body mass index.

Absorptiometry, Photon↗
PubMed2000

Diabetes-related emotional distress in Dutch and U.S. diabetic patients: cross-cultural validity of the problem areas in diabetes scale.

OBJECTIVE: To examine the cross-cultural validity of the Problem Areas in Diabetes Scale (PAID) in Dutch and U.S. diabetic patients. RESEARCH DESIGN AND METHODS: A total of 1,472 Dutch people with diabetes completed the PAID along with other self-report measures of affect. Statistics covered Cronbach's alpha, exploratory factor analysis (EFA), and confirmatory factor analysis (CFA), Pearson's product-moment correlation, and t tests. Psychometric properties of PAID were compared for Dutch and U.S. diabetic patients. RESULTS: Internal consistency of the Dutch PAID was high and stable across sex and type of diabetes. Test-retest reliability was high. Principal component analyses confirmed 1 general 20-item factor, whereas EFA identified 4 new subdimensions: negative emotions, treatment problems, food-related problems, and lack of social support. These dimensions were confirmed with CFA and were replicated in the U.S. sample. The PAID and its subscales demonstrated moderate to high associations in the expected direction with other measures of affect. Dutch and U.S. subjects reported having the same problem areas, with U.S. patients reporting higher emotional distress levels both in type 1 and type 2 diabetes. CONCLUSIONS: The Dutch and U.S. 20-item PAID appeared to be psychometrically equivalent, which allowed for cross-cultural comparisons.

Anxiety↗
PubMed1997

The role of early HIV infection in the spread of HIV through populations.

The combination of two factors gives early HIV infection an especially strong influence on transmission dynamics: (a) increased transmission probabilities and (b) increased transmission potential of partners infected during this period. Most attention has been focused on the first factor because it fits the way we usually think about risk factors affecting individuals. The second factor acts not on individuals, but across chains of transmission. It is missed by models with constant partnership formation rates over an individual's life or with random mixing. It cannot be assessed from available data collected from individuals. Its assessment requires data from both individuals in a partnership. We demonstrate that this second effect can be so strong that early infection can dominate transmission dynamics even when transmission probabilities are only modestly increased. This second effect is not directly parameterized in our models but arises from two realistic types of temporal variation in partnership formation: (a) Partnership formation rates vary by age with preferential partnership formation in one's own age group, and (b) individuals of any age can experience transient periods of high-risk partnership formation. In a model with only the age-related effect, early infection is observed to dominate transmission dynamics when 20% of transmissible virus is allocated to the first 6 weeks of infection, 7% to middle infection, and 73% to late infection. This domination occurs both early in the course of an epidemic and later when endemic infection levels have been reached. When the second effect is added, early infection is seen to dominate transmission in a model allocating 10% of transmissible virus to the first 6 months, 40% to middle infection, and 50% to late infection. In this model, transmission probabilities during early infection are only 4.17 times those of middle infection and half those of late-stage infection.

Age Factors↗
PubMed1997

Women with insulin-dependent diabetes mellitus (IDDM) complicated by eating disorders are at risk for exacerbated alterations in lipid metabolism.

OBJECTIVE: To examine lipid parameters that are affected in women with insulin-dependent diabetes mellitus (IDDM) who engaged in disordered eating behaviours. DESIGN: Randomized, unmatched. SETTING: Tertiary care. SUBJECTS: Ninety women (18-46 y) with IDDM. INTERVENTIONS: Classification of subjects based on severity of eating disorder: clinical (n = 14), subclinical (n = 13) and control (n = 63). Blood was analysed for glycosylated haemoglobin (HbA1c) and serum for triglycerides and cholesterol. Carotenoid and tocopherol concentrations were analysed by high performance liquid chromatography (HPLC). Dietary intake was assessed by the National Cancer Institute food frequency questionnaire. RESULTS: HbA1c was significantly increased im women demonstrating clinical and subclinical symptoms compared to control (10.4 +/- 2.6, 10.0 +/- 1.5 and 8.3 +/- 1.6%, respectively, P < 0.05). Triglycerides concentrations were significantly increased in women with subclinical eating disorders compared to controls. In women who intentionally omitted or reduced insulin, triglyceride cholesterol and HbA1c were significantly increased compared to controls. Women with IDDM and eating disorders who exhibited bulimic behaviours consumed significantly more energy, total fat and cholesterol compared to controls and women with eating disorders who were restrained eaters. CONCLUSION: While IDDM is known to perturb lipid metabolism, these data demonstrate that eating disorders, in combination with IDDM, results in additional alterations in lipid metabolism.

Adolescent↗
PubMed1997

Subclinical and clinical eating disorders in IDDM negatively affect metabolic control.

OBJECTIVE: To characterize the relationship of subclinical and clinical eating disorders to HbA1c values in women with IDDM. RESEARCH DESIGN AND METHODS: Ninety women with IDDM (18-46 years of age) were recruited from diabetes clinics throughout Connecticut and Massachusetts. Subjects were categorized into one of three groups according to the Diagnostic Statistical Manual of Mental Disorders (DSM-III-R) criteria for eating disorders as follows: the clinical group (n = 14), the subclinical group (partially fulfilling the diagnostic criteria; n = 13), and the control group (n = 63). Group differences in the degree of dietary restraint, binge eating, and bulimic behaviors and weight, shape, and eating concerns were assessed with the Eating Disorder Examination (EDE) and the Bulimia Test Revised (BULIT-R). RESULTS: Women with subclinical and clinical eating disorders had clinically elevated HbA1c results and more diabetes-related complications, compared with the control subjects. The severity of bulimic behaviors, weight concerns, reduced BMI, and decreased frequency of blood glucose monitoring were associated with elevated HbA1c. CONCLUSIONS: HbA1c may have clinical utility in the identification of eating disorder behavior in females with IDDM. Health care professionals should be aware of the potent effect of subclinical and clinical eating behaviors including insulin misuse in weight-conscious women with IDDM who have poor glycemic control.

Adolescent↗
PubMed1997

The Problem Areas in Diabetes Scale. An evaluation of its clinical utility.

OBJECTIVE: To evaluate the reliability and concurrent and discriminant validity of the Problem Areas in Diabetes (PAID) scale, a new measure of emotional functioning in diabetes. RESEARCH DESIGN AND METHODS: A battery of questionnaires, including the PAID, was completed by 256 volunteer diabetic outpatients. In our analyses, we examined the PAID's internal structure and compared mean IDDM and NIDDM treatment group scores in regression analyses to explore its discriminant validity. We also evaluated concurrent validity from the correlations between the PAID and diabetes-specific measures of coping and health attitudes and HbA1c. RESULTS: Principal component analyses identified a large emotional adjustment factor, supporting the use of the total score. Significant sizable correlations were found between the PAID and a range of selected health attitudinal measures. There were significant differences (with small-to-moderate effect sizes) in PAID scores between IDDM and NIDDM patients and between IDDM and NIDDM insulin- and tablet-treated subgroups; no differences were found between NIDDM insulin- and tablet-treated subgroups. CONCLUSIONS: The study findings provided support for the construct validity of the PAID, including evidence for discriminant validity from its ability to detect differences between IDDM and NIDDM treatment groups expected to differ in the emotional impact of life with diabetes. Future studies should explore the PAID's performance in nonspecialist treatment settings as well as its responsiveness to clinical change.

Adaptation, Psychological↗
PubMed1991

FACTOREP: a new tool to explore the dimensions of depression.

One promising research approach in the search for clinically meaningful diagnostic categories of depression has been the application of multivariate statistical techniques such as factor analysis to the evaluation of self-report and observer rating data. The contribution of factor analysis has been limited, however, by the application of traditional mathematical criteria in the analyses which typically produce too many factors. In this study, a criterion of replicability was applied with the aid of a factor matching procedure (FACTOREP). The Beck Depression Inventory (BDI) was examined using FACTOREP and two large samples of depressed patients. The results showed that only a large general factor was present. Beyond the BDI studies, there has been debate on the validity of the endogenous versus reactive depression conceptualization. Despite the limited number of endogenous items in the BDI, the results here did not confirm the presence of two clear factors that represented endogenous and reactive groups of items.

Affective Disorders, Psychotic↗
PubMed1990

Functional gastrointestinal symptoms in a Wellington community sample.

In this study, gut functioning and the prevalence of functional bowel disorders among a Wellington community sample of 285 apparently healthy people was estimated using a standardised questionnaire. When asked for their opinion of their bowel functioning generally, 37% of respondents were satisfied that it was always normal, 57.2% regarded it as not always normal, and 5.6% felt it was normal less than half the time or not normal at all. However, only 11.6% had actually consulted a physician about a stomach or bowel disorder in the past year. Average bowel frequency was 8.4 movements per week (SD = 3.9) for the total sample. Approximately three quarters of the total sample had experienced diarrhoea at least occasionally, but only 2.5% half the movements or more often. Constipation was reported by 8.1% for half the time or more, and 1.8% for most bowel movements. Abdominal distension was experienced by 7.2% on half of days or more, and 3.6% on most days or daily. Abdominal pain occuring on six or more separate days in the previous year was reported by 26.4% of men and 31.9% of women. Pain not due to organic disorders that was colonic in nature and of the irritable bowel syndrome type was reported by 15.9% of men and 17.2% of women.

Abdominal Pain↗
PubMed1990

Pediatric trauma triage: review of 1,307 cases.

To assess patterns of pediatric trauma triage and patient transfer to the pediatric trauma centers, the records of 1,307 patients 14 years old or less who were admitted or died during resuscitation at eight Level II Trauma Centers from January 1987 through December 1988 were reviewed retrospectively. Cases were analyzed according to the following criteria: age, diagnosis, mechanism of injury, admitting service, pediatric trauma score (PTS), length of stay in the intensive care unit (ICU) and in the hospital, and outcome. Forty-three patients were transferred to pediatric trauma centers based on local criteria. Of the remaining 1,264 patients kept at the Level II Trauma Centers, the average patient age was 8.34 year; PTS, 9.74; and length of stay, 4.46 days. Two hundred fifty-eight patients (19.7%) required ICU care for an average length of stay of 2.86 days. Twenty-four patients (1.8%) died; all 24 had a PTS less than or equal to 8. In comparing the data to the guidelines in Appendix J of the American College of Surgeons' Hospital and Prehospital Resources for Optimal Trauma Care of the Injured Patient for transfer to a Level I Pediatric Trauma Center, we found that children with a PTS greater than 8 and who either require ICU care and/or have altered states of consciousness can safely be treated in the adult ICU of a Level II Trauma Center.

Adolescent↗
PubMed1988

Evaluation of the Datascope ACCUSAT pulse oximeter in healthy adults.

Arterial hemoglobin oxygen saturation measured with the Datascope ACCUSAT pulse oximeter was compared with simultaneous arterial hemoglobin oxygen saturation measurements in healthy adult volunteers. One hundred thirty-five arterial blood samples ranging in saturation from 63 to 100% were obtained from 15 adults, aged 20 to 43 years. These subjects had different skin pigmentation, hematocrit, and smoking habits. Steady-state hypoxia was achieved by varying the inspired oxygen concentration between 10 and 21%. Readings from the Datascope ACCUSAT pulse oximeter and the Hewlett-Packard 47201A ear oximeter were compared with arterial blood samples analyzed by the Instrumentation Laboratories IL 282 in vitro CO-Oximeter. The equation for the best fitted linear regression line between the ACCUSAT pulse oximeter and the reference IL 282 CO-Oximeter was: ACCUSAT = 1.08(IL) - 6.86. The linear regression analysis revealed a high degree of correlation (r = 0.99), and a small standard error of the estimate (SEE = 1.29%). Simultaneous comparisons between arterial hemoglobin oxygen saturation measured with the ACCUSAT pulse oximeter and the Hewlett-Packard ear oximeter also showed a close correlation (r = 0.99, SEE = 1.47%). A similar comparison between the ACCUSAT and the Ohmeda 3700 pulse oximeter revealed good correlation (r = 0.99, SEE = 1.72%). We found that the ACCUSAT pulse oximeter is an accurate instrument for measuring arterial hemoglobin oxygen saturation noninvasively in the range between 60 and 100%.

Adult↗
PubMed1987

Simultaneous comparison of three noninvasive oximeters in healthy volunteers.

Noninvasive monitoring of arterial hemoglobin oxygen saturation (SaO2) from the Nellcor N-100 and the Ohmeda-Biox 3700 pulse oximeters were compared with SaO2 measured simultaneously by the Hewlett-Packard 47201A ear oximeter. A total of 868 pairs of data points ranging in saturation from 55-100% were obtained from 31 healthy adult volunteers of different ages, sex, skin pigmentation, height, weight, hematocrit, and smoking habits. Steady state and rapidly changing hypoxic conditions were achieved by varying the inspired O2 concentration between 10 and 100%. Measurements were analyzed by means of linear regression. The equations for the best fitted linear regression line between the Nellcor and the Ohmeda-Biox pulse oximeters as compared to the reference Hewlett-Packard ear oximeter readings were Y = 0.92X + 7.45 and Y = 1.10X - 10.73, respectively. Our study showed that despite a very close correlation among these three oximeters (r = 0.98), when compared to the Hewlett-Packard ear oximeter, the Nellcor pulse oximeter overestimates SaO2 by 2-4%, whereas the Ohmeda-Biox pulse oximeter underestimates SaO2 by 3-6% for SaO2 levels between 70 and 55%.

Adult↗
PubMed1985

Psychoneurotic symptomatology in the irritable bowel syndrome: a study of reporters and non-reporters.

An appreciable proportion of the general population have the irritable bowel syndrome but do not report it. Results of psychological assessments showed that outpatients with the syndrome and non-reporters of it were psychologically similar, but both groups showed more somatic distress than normal controls. Anxiety, depression, obsessive compulsion, and interpersonal sensitivity were similar in both groups with the syndrome and the normal controls. The preponderance of women referred to outpatient clinics may reflect sociological factors rather than the severity of the irritable bowel syndrome.

Adolescent↗
PubMed1984

Specificity of psychological profiles of irritable bowel syndrome patients.

The aim of the study was to investigate the specificity of psychological profiles in female Irritable Bowel Syndrome (IBS) patients by a comparison with a gastrointestinal patient control group and with a normal population control group. The results showed that the IBS patients scored significantly higher than the normal population sample on three test scales: Anxiety, Phobic and Somatisation. Our results thus support the conclusion of earlier authors that a moderate degree of psychoneurotic disorder exists amongst IBS patients. However, the patient control group also scored significantly higher than the normal control group on two factors (Phobic and Somatisation), and the comparison between the IBS group and the patient control group did not reveal any significant differences. It is suggested that attention to the psychological needs of both IBS and other gastrointestinal disease patients should form an important part of the management strategy, particularly in the former--where a consistently clear benefit for any particular therapy has yet to be shown.

Anxiety↗
PubMed1982

Effect of bretylium on neuromuscular transmission.

The effect of bretylium on the response of an isolated muscle (guinea pig lumbrical) to direct and indirect stimulation was examined. An initial increase in twitch response to both indirect and direct stimulation was followed at higher concentrations of bretylium by block of the indirect response only. The ED50 for this latter effect was 106.9 +/- 9.25 microM. However, in the presence of subthreshold levels of d-tubocurarine the ED50 was markedly reduced to 1.31 +/- 1.11 microM, a concentration that could occur during clinical use of bretylium. Thus, the physician is cautioned to consider the possibility that neuromuscular block may be produced when bretylium is administered in close temporal proximity to neuromuscular blocking agents.

Animals↗