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Biomedical subjects

K Larson

Publications and source records attributed to K Larson.

At least 19 recordsLinked to original sources
PubMed1993

Effect of phenylpropanolamine on energy expenditure and weight loss in overweight women.

The effect of phenylpropanolamine (PPA), a noncatecholamine sympathomimetic weight-loss agent, on energy expenditure (EE) and substrate oxidation was measured in a respiratory chamber in 24 overweight women after 4 d of treatment (PPA or placebo) during weight maintenance and after 7 wk of treatment on a hypoenergetic diet (70% of measured baseline 24-h EE). Twelve women (37 +/- 2 y, 74 +/- 6 kg, 33 +/- 1% body fat) were randomly assigned to the PPA group [75 mg osmotic release oral system (OROS)-PPA/d] and 12 (mean +/- SEM: 38 +/- 2 y, 79 +/- 1 kg, 37 +/- 1% body fat) to the placebo group. Baseline measurements of 24-h EE (7849 +/- 226 vs 7834 +/- 142 kJ/d), basal metabolic rate (BMR) and 24-h respiratory quotient (RQ) were comparable between PPA and placebo groups. After 4 d of treatment, there was no significant effect of PPA on 24-h EE, BMR, and 24-h RQ compared with placebo. Over the 7-wk diet period, however, the PPA group (n = 8) had greater weight loss than the placebo group (n = 10): -5.0 +/- 0.5 vs -3.0 +/- 0.4 kg (P < 0.05). The changes in 24-h EE and 24-h RQ over the 7 wk were not different between the groups. We conclude that weight loss is enhanced by OROS-PPA, but this change was not explained by changes in 24-h EE or 24-h RQ. The small number of subjects may have hindered detection of subtle differences in energy metabolism.

Adolescent↗
PubMed1993

The prognostic utility of delayed-type hypersensitivity skin testing in the evaluation of HIV-infected patients. Military Medical Consortium for Applied Retroviral Research.

Many reagents and techniques have been used for delayed-type hypersensitivity (DTH) skin testing in the evaluation of HIV-infected patients, resulting in varied interpretation of the utility of DTH skin testing in this population. We report the development of a simple algorithm for selection of DTH antigens and the clinical relevance of DTH skin testing in HIV disease. Antigens and concentrations for testing were first evaluated in a demographically matched, HIV-negative, immunologically healthy population. The testing scheme was then applied to the HIV population of interest for 5 years at several clinical sites. The antigens and concentrations selected resulted in 100% reactivity to two or more antigens in the HIV-negative cohort. Anergy is thus a distinct immunologic abnormality. Although some correlation (r2 = 0.6) of skin test reactivity and CD4 cell count was found in a cohort of HIV-infected individuals, anergy was found to be independently predictive of the development of symptomatic late-stage disease (Walter Reed Stage 6), AIDS, or death. This stepwise evaluation of skin testing and reagents has led to the modification of the skin testing protocol by defining the minimum number of antigens required and establishing the independent prognostic role of DTH skin testing in the evaluation of HIV-infected patients. The addition of mumps (40 CFU/ml), tetanus (1:10), and candida (1:10) to the purified protein derivative (PPD) skin test provides the critical controls to evaluate the status of PPD skin test in HIV-infected individuals as well as to provide a useful and prognostic clinical immunology evaluation.

Adult↗
PubMed1992

Incidence of common postural abnormalities in the cervical, shoulder, and thoracic regions and their association with pain in two age groups of healthy subjects.

The purposes of this study were to identify the incidence of postural abnormalities of the thoracic, cervical, and shoulder regions in two age groups of healthy subjects and to explore whether these abnormalities were associated with pain. Eighty-eight healthy subjects, aged 20 to 50 years, were asked to answer a pain questionnaire and to stand by a plumb line for postural assessment of forward head, rounded shoulders, and kyphosis. Subjects were divided into two age groups: a 20- to 35-year-old group (mean = 25, SD = 63) and a 36- to 50-year-old group (mean = 47, SD = 2.6). Interrater and intrarater reliability (Cohen's Kappa coefficients) for postural assessment were established at .611 and .825, respectively. Frequency counts revealed postural abnormalities were prevalent (forward head = 66%, kyphosis = 38%, right rounded shoulder = 73%, left rounded shoulder = 66%). No relationship was found between the severity of postural abnormality and the severity and frequency of pain. Subjects with more severe postural abnormalities, however, had a significantly increased incidence of pain, as determined by chi-square analysis (critical chi 2 = 6, df = 2, P less than .05). Subjects with kyphosis and rounded shoulders had an increased incidence of interscapular pain, and those with a forward-head posture had an increased incidence of cervical, interscapular, and headache pain.

Adult↗
PubMed1991

Treatment of pyoderma gangrenosum with cyclosporine: results in seven patients.

The mainstay of therapy for pyoderma gangrenosum has been corticosteroids, but many patients respond poorly. During the past 2 years we have treated seven patients who had pyoderma gangrenosum with cyclosporine after their condition proved resistant to conventional therapy. No evidence of permanent toxicity from cyclosporine was detected and treatment with other immunosuppressive agents was discontinued in five of seven cases. Tuberculosis was reactivated in one patient. Three patients had a remission, three had an intermediate response, and one did not respond. These results indicate that cyclosporine is useful in the treatment of patients with refractory pyoderma gangrenosum and suggest an immune mechanism in the pathogenesis of this disorder.

Adult↗
PubMed1991

Body composition in Pima Indians: validation of bioelectrical resistance.

To assess the validity of bioelectrical resistance (BR) in an obese population, body composition was determined by both hydrostatic weighing and by BR in 156 Pima Indian volunteers representing a wide range of body weight (46.1-202.6 kg) and body composition (11-52% fat). A predictive equation was derived by use of data on height, BR, weight, age, and sex from 130 randomly selected volunteers and was applied to the remaining 26 volunteers. When compared with the manufacturer's software, the new equation increased correlations with hydrostatic weighing for predicting percent body fat and fat-free mass (FFM) from 0.70 to 0.92 and 0.79 to 0.97, respectively. The manufacturer's software underestimated FFM by 5.3 +/- 8.6 kg (P less than 0.05) when compared with FFM derived from hydrostatic weighing whereas the new equation improved the accuracy to -0.1 +/- 3.3 kg (NS). There were no significant effects of fluid intake (700 mL) or breakfast consumption on body composition as determined by BR. BR represents a simple and accurate way to assess body composition in Pima Indians with our newly derived equation.

Adipose Tissue↗
PubMed1991

Magnetic resonance imaging of cutaneous neoplasms: clinicopathologic correlation.

Recently, magnetic resonance imaging (MRI) has been reported to be clinically useful, in selected cases, in patients with melanocytic skin lesions. This report describes good resolution, clinically useful MRI scans of squamous cell carcinoma, dermatofibroma, and primary cutaneous B-cell lymphoma. The tumor depth measured by MRI was in excellent correlation with Breslow's depth measurements, indicating that MRI is probably the radiologic technique of choice for preoperative evaluation of the extent and depth of primary and recurrent skin tumors. This report also provides the authors' recommendations for obtaining optimal MRI images of cutaneous lesions.

Adult↗
PubMed1991

Muscle mitochondrial morphology, body composition, and energy expenditure in sedentary individuals.

To investigate whether differences in metabolic rate are related to differences in muscle mitochondrial morphology and/or to differences in in vitro muscle respiration, we studied 17 healthy Caucasians, covering a wide range of body weight and composition [9 males, 8 females; body wt 96 +/- 37 (SD) kg; body fat = 28 +/- 10%]. Central and peripheral mitochondrial volume density (Vmit c and Vmit p, respectively) and the ratio of mitochondrial outer surface to volume of mitochondria (SVmit c in center and SVmit p at periphery) were determined by stereological analyses of transmission electron micrographs from samples of the vastus lateralis. There was no relationship between mitochondrial morphology or muscle respiration and 24-h energy expenditure, basal metabolic rate, or sleeping energy expenditure adjusted for differences in fat-free mass, fat mass, age, and sex. Although total body fat was not associated with muscle cell morphology, central distribution of body fat [waist-to-thigh circumference ratio (W/T)] correlated negatively with Vmit c (r = -0.58, P = 0.01), SVmit c (r = -0.59, P = 0.01), and SVmit p (r = -0.48, P = 0.05). W/T was also negatively related to muscle respiration (r = -0.59, P = 0.01). Despite the lack of relationship between metabolic rate and muscle mitochondrial morphology, central distribution of body fat is associated with lower mitochondrial density and larger mitochondria in skeletal muscle and is associated with a decreased oxidative capacity of muscle.

Adult↗
PubMed1990

The effects of contingent music and differential reinforcement on infantile colic.

Infantile Colic is a behavioral syndrome characterized by paroxysms of excessive crying and increased motor activity, hypertonicity of the musculature, excessive flatus and erratic sleeping and feeding patterns. Ten to 40% of all infants are diagnosed as having Colic. The medical evidence to date does not justify any conclusions regarding the etiology or treatment of Colic. Typically, parents are advised to simply wait until Colic has run its course which is often 3-4 months. The behavioral program reported here was designed to increase behavior that competed with crying by reinforcing quiet alertness with music and parental attention. Concurrently, it attempted to inhibit excessive crying by a brief time-out procedure. A group of 8 infants diagnosed as Infant Colic were included in this study. The dependent variable, crying, was measured through direct observations based on hourly samples involving 30 observations of 2-min intervals. The independent variable consisted of a behavioral treatment package. A within-S reversal design was used to assess the functional properties of the treatment. The results show that across all 8 infants the introduction of the treatment package led to a substantial decrease in excessive crying of about 75% of the initial baseline. Further, a functional relationship was identified between the treatment and excessive crying behavior: crying decreased when the treatment was initially introduced, it resumed when the treatment was withdrawn and decreased again when the treatment was reinstated.

Attention↗
PubMed1990

Skeletal muscle metabolism is a major determinant of resting energy expenditure.

Energy expenditure varies among people, independent of body size and composition, and persons with a "low" metabolic rate seem to be at higher risk of gaining weight. To assess the importance of skeletal muscle metabolism as a determinant of metabolic rate, 24-h energy expenditure, basal metabolic rate (BMR), and sleeping metabolic rate (SMR) were measured by indirect calorimetry in 14 subjects (7 males, 7 females; 30 +/- 6 yr [mean +/- SD]; 79.1 +/- 17.3 kg; 22 +/- 7% body fat), and compared to forearm oxygen uptake. Values of energy expenditure were adjusted for individual differences in fat-free mass, fat mass, age, and sex. Adjusted BMR and SMR, expressed as deviations from predicted values, correlated with forearm resting oxygen uptake (ml O2/liter forearm) (r = 0.72, P less than 0.005 and r = 0.53, P = 0.05, respectively). These findings suggest that differences in resting muscle metabolism account for part of the variance in metabolic rate among individuals and may play a role in the pathogenesis of obesity.

Adult↗
PubMed1990

Interexaminer reliability of eight evaluative dimensions of lumbar segmental abnormality.

The interexaminer reliability of noninvasive methods of examining lumbar spinal segments is not well established. In this project the interexaminer reliability of three experienced chiropractic examiners, who evaluated 21 symptomatic and 25 asymptomatic subjects, was explored. Eight noninvasive segmental examination strategies (dimensions) were employed at each spinal segment from T11/T12 through L5/S1. Marginal to good agreement beyond chance was noted for palpatory pain over osseous structures and in paraspinal soft-tissues. Weaker and less frequently, significant concordance between examiners was noted for detection of temperature differences (greater than or equal to 1.5 degrees F) between adjacent segments and for visual inspection for segmental abnormality. Little significant agreement between examiner was found for active and passive motion palpation, muscle tension palpation and misalignment palpation. This study suggests that "subjective" findings (pain) may be among the most reliable of conservative spinal observations. Weak but significant correlations were found when positive findings for the eight dimensions at each lumbar segment were summed to form a composite joint abnormality index. When the multidimension index was developed using the four most reliable dimensions, slightly stronger correlations were found. The strongest agreement between examiners tended to be found in the lower lumbar spine.

Adult↗
PubMed1989

Energy expenditure during normo- and overfeeding in peripubertal children of lean and obese Pima Indians.

We investigated the hypothesis that peripubertal children born to obese parents have a lower 24-h energy expenditure during "weight maintenance" and/or in response to overfeeding when compared with children born to normal-weight parents. Sixteen Southwestern American Indians (12.4 +/- 1.4 yr, 55.5 +/- 14.1 kg, 30 +/- 8% body fat), eight offspring from obese parents [body mass index (BMI) = 40 +/- 6 kg/m2], and eight offspring from thin parents (BMI = 24 +/- 3 kg/m2) were admitted for 8 days to our metabolic ward. The 24-h energy expenditure was measured under eucaloric conditions and on the 3rd day of progressive overfeeding of a mixed diet, i.e., 150, 200, and 200% of weight maintenance on day 1, 2, and 3 of overfeeding. At base line, offspring of obese parents were heavier (64 +/- 15 vs. 47 +/- 6 kg, P less than 0.05) and tended to be fatter (34 +/- 8 vs. 26 +/- 9% body fat, P = 0.07), with a higher absolute fat mass (22 +/- 9 vs. 13 +/- 4 kg body fat, P less than 0.05) when compared with offspring of thin parents. During both normo- and over-feeding, the larger part of the variance in 24-h energy expenditure in the conditions of a respiratory chamber was accounted for by differences in fat-free body mass (54 and 68%, respectively), whereas differences in the level of spontaneous physical activity accounted for another 19 and 21%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Journal of Manipulative & Physiological Therapeutics: a bibliographic analysis.

The first 9 years of the Journal of Manipulative and Physiological Therapeutics (JMPT) (1978-1986) were surveyed to determine concentrations of research activity, educational backgrounds of contributors, sources of funding for chiropractic science, and the volume and kinds of research in chiropractic. Most articles were authored by chiropractors but a fourth of all articles included contributors with scientific/academic doctorates. Most chiropractors were affiliated with a chiropractic college, but collaboration among chiropractic colleges was rare. A recent increase in contributions from private practitioners was also evident. Authors with medical training were uncommon (6%). National College and Canadian Memorial together accounted for 43% of all articles, and 72% of papers whose authors gave chiropractic college affiliations. Authors acknowledged 30 funding sources, and the Foundation for Chiropractic Education and Research (FCER) accounted for a third of all grants (18 of 55). Empirical studies increased in frequency from 1978 to 1986, but accounted for less than half of the papers. Case reports have been the most common form of original data report; 39 were published in JMPT during the 9 year period. Controlled clinical trials of chiropractic healing methods were extremely rare (3 of 334 papers). A need for greatly expanded clinical research in chiropractic is suggested.

Abstracting and Indexing↗
PubMed1988

An interdisciplinary psychoeducation program for schizophrenic patients and their families in an acute care setting.

A psychoeducation program in an acute care inpatient psychiatric setting involves schizophrenic patients and their families in a range of educational interventions that are responsive to their particular strengths and vulnerabilities. Patients receive one-on-one instruction about their illness from a psychiatrist and the nursing staff and learn community living skills in classes and tutorials conducted by occupational therapists. Families discuss ways of coping with the patients' illness in a series of meetings with a social worker, and they attend workshops led by a team of clinicians and an administrator, who advise them of current perspectives on the illness and its management and about how to negotiate the mental health system. A mental health library keeps staff, family, and patients abreast of recent literature about schizophrenia. The authors believe the program prepares patients to live in the community better than do programs whose goals are limited to symptom reduction or crisis intervention.

Adaptation, Psychological↗
PubMed1987

Inhibition of postbinding target cell lysis and of lymphokine-induced enhancement of human natural killer cell activity by in vitro exposure to ultraviolet B radiation.

In vitro exposure of human peripheral blood mononuclear cells (PBMC) to ultraviolet B (uvB) radiation has been shown to inhibit natural killer (NK) cell-mediated cytotoxicity in a dose-dependent fashion. The purpose of this study was to examine the manner by which uvB produced these deleterious effects. Inhibition of NK activity was not due to lethal injury to NK cells since the viability of cell populations enriched for NK activity was greater than 90% with the uvB doses employed. uvB appeared to directly affect NK cells since procedures which removed suppressor mechanisms, such as removal of monocytes and pharmacologic inhibition of the cyclooxygenase pathway, failed to reverse the response. Furthermore, no suppression of activity of unirradiated NK cells could be produced by coincubation of unirradiated NK cells with uv-irradiated NK cells. When the single cell assay for binding and killing was employed to determine at which stage in the lytic sequence inhibition occurred, it was found that binding was normal but lysis of bound targets and the recycling capacity of active NK cells were markedly reduced. At uvB doses above 50 J/m2, both interferon alpha (IFN-alpha) and interleukin 2 (IL-2) were ineffective in augmenting NK cell-mediated cytotoxic reactions after cells had been irradiated with uvB. Furthermore, incubation of NK cells with IFN-alpha prior to irradiation failed to protect against the inhibitory effects. These studies provide evidence that in vitro exposure of NK cells to uvB radiation inhibits their function by a direct nonlethal effect and that this inhibition occurs selectively at the postbinding stage of target cell lysis.

Cytotoxicity, Immunologic↗