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Biomedical subjects

L Backman

Publications and source records attributed to L Backman.

At least 19 recordsLinked to original sources
PubMed1992

Swedish obese subjects (SOS). Recruitment for an intervention study and a selected description of the obese state.

SOS (Swedish obese subjects) is an on-going intervention trial designed to determine whether the mortality and morbidity rates among obese individuals who lose weight by surgical means (gastric banding, vertical banded gastroplasty and gastric by-pass) differ from the rates associated with conventional treatment. For this purpose, the study is recruiting a sample of obese men and women who constitute a registry of potential subjects from which the participants are drawn. Eligibility criteria for participation in the registry were: age at application 37-57 years and BMI greater than or equal to 34 kg/m2 for men and greater than or equal to 38 kg/m2 for women. Before receiving a health examination, all patients complete extensive questionnaires on current and past health status, utilization of medical care and medications, socio-economic status, psychological profiles, dietary habits, physical activity, weight history, and familial disposition to obesity. Each surgical case is matched to its optimal control in the registry, to ensure that the two groups do not differ systematically with respect to any of 18 matching variables that may affect prognosis. The first 1006 subjects included in the registry have been studied with respect to morbidity and compared with on-going population studies of men and women in Göteborg, Sweden. The relative risks of prevalent disease and symptoms associated with obesity in 50-year-old males and females respectively were 4.3 and 4.7 (dyspnoea), 14.7 and 11.8 (angina), 6.3 (myocardial infarction, males only), 2.1 and 4.5 (hypertension), 5.2 and 6.6 (diabetes), 4.6 and 26.1 (claudication) and 1.7 and 1.8 (gall bladder disease). Correspondingly, obese males and females display elevations of systolic and diastolic blood pressure, fasting glucose, insulin, triglyceride, and uric acid levels. However, total cholesterol was not increased in obese males and was in fact significantly lower in obese compared with reference women. HDL-cholesterol was lower in obese than reference men (data were not available in reference women). The rate of taking sick pensions was over twice as high in SOS obese patients than in population controls. Finally, comparison of measurements with self-reported prevalence estimates revealed a considerable amount of previously undiagnosed hypertension and diabetes in the obese subjects. These data suggest that the excess health risks associated with obesity may not be fully appreciated.

Adipose Tissue↗
PubMed1979

Role of hemoglobin in proton transfer to the active site of carbonic anhydrase.

The binding of bovine oxyhemoglobin to bovine carbonic anhydrase with a dissociation constant between 10(-5) and 10(-7) M has been determined by countercurrent distribution using aqueous, biphasic polymer systems. This result provides an explanation for the very efficient proton transfer between hemoglobin and carbonic anhydrase, a transfer which enhances the catalytic activity of carbonic anhydrase as measured by 18O exchange between bicarbonate and water at chemical equilibrium (Silverman, D. N., Tu, C. K., and Wynns, G. C. (1978) J. Biol. Chem, 253, 2563-2567). Two rate constants describing 18O exchange activity of carbonic anhydrase at pH 7.5 show saturation behavior when plotted against hemoglobin concentration consistent with a dissociation constant of 2.5 X 10(-6) M between bovine hemoglobin and carbonic anhydrase. Interpretation of these rate constants in terms of a two-step model for 18O exchange indicates that hemoglobin enhances the rate of exchange from carbonic anhydrase of water containing the oxygen abstracted from bicarbonate, but does not affect the catalytic interconversion of CO2 and HCO3- at chemical equilibrium.

Animals↗
PubMed1979

Protein-protein interactions studied by counter-current distribution. I. Theoretical computations.

Many biological macromolecules are known to interact either with themselves, with other macromolecules or with small compounds. A simple equilibrium method for detecting and quantifying these interactions is to study the mutual influence of the molecules on their respective counter-current distribution in liquid-liquid biphasic systems. The theoretical counter-current distribution patterns for the components in an interacting system, A + B in equilibrium AB, have been calculated for two models in order to establish the boundary conditions and to optimize the experimental procedure. The patterns have been calculated for a range of association constants, partition coefficients and initial concentrations of the two reactants.

Countercurrent Distribution↗
PubMed1979

The incidence of urinary tract calculi after small-intestinal bypass operations for treatment of obesity.

Jejunoileal bypass operations have been used for more than 20 years for the treatment of massive obesity. This treatment results in malabsorption with diarrhoea, especially during the first year after the operation. A high incidence of urinary tract calculi have been found in these patients (4, 5, 15, 19, 24). Other known late complications are transient disturbances in liver function and electrolyte balance (5).

Adolescent↗
PubMed1979

The value of preoperative S-LD 5 isoenzyme determination in predicting the risk of serious liver injury after bypass operations for treatment of obesity.

After bypass operations for obesity many patients had signs of liver injury (SLI). It has not earlier been possible to correlate changes in the preoperative liver function test with occurrence of postoperative SLI. The present study shows that those patients who before the intestinal bypass operation had a moderate to significant change in serum activity of S-LD 5 (isoenzyme 5 of the enzyme lactate dehydrogenase) were at risk of developing SLI after the operation. All five patients with SLI, of whom three died, preoperatively had an increase in S-LD 5 exceeding five times the normal mean value. The pattern in the transaminases and serum alkaline phosphatase were not as conclusive.

Adult↗
PubMed1978

Tuberculosis after intestinal bypass operations.

Two cases of tuberculous infections occurred after intestinal shunt operations for obesity among 161 patients observed for more than one year. One died of generalized tuberculosis. Another 2 patients, who before the operation had had tuberculosis, managed well without signs of postoperative activation of the tuberculous infection seems to be unpredictable.

Adult↗
PubMed1977

S-tryptophan concentrations after intestinal bypass in extreme obesity.

Treatment of extreme obesity with jejunoileostomy was followed by a decreased level of S-tryptophan; permanently low concentrations were recorded postoperatively in 29 out of 52 patients. Patients in the low tryptophan group had a higher rate of weight loss and a hgiehr incidecnce of electrolyte disturbances and signs of liver injury. Symptoms of depression and anxiety were slightly more common in patients with low S-tryptophan. The influence of a decreased S-albumin and a deranged amino acid pattern on the non-protein-bound fraction of S-tryptophan needs further investigation. Serum levels of tryptophan rose significantly after rwo weeks' oral supplementation with 1.2 g L-tryptophan daily; this dosage was insufficient to normalize a low S-tryptophan level in patients who have undergone jejunoileostomy.

Administration, Oral↗
PubMed1976

Immunological function in patients operated on with small intestinal shunts for morbid obesity.

Obese individuals, operated on with intestinal shunts, have been investigated with regard to immunological functions. After operation strong increases in skin reactions of immediate and delayed type were observed. Analysis of total WBC and differential counts, percentage T lymphocytes, immunoglobulin concentrations, and lymphocyte reactivity yielded no explanation of the findings.

Humans↗
PubMed1976

Morphological changes of the small intestine following jejuno-ileal shunt in obese subjects.

The forty-seven patients in this study suffered of massive obesity and underwent jejuno-ileal shunt operations. Seventeen of them had a second laparotomy for various reasons. At both operations, a number of measurements were made; the length of the functioning jejunal and ileal segments and, in biopsies, the intestinal villus height were determined. The second laparotomies were not performed until at least 6 months after establishment of jejuno-ileal bypass. The mean length of functioning jejunum was increased by 33% (p less than 0.05) and the mean elongation of functioning ileum by 73% (p less than 0.001). The mean villus height in functioning jejunum increased by 33% (p less than 0.001) and in functioning ileum by 70% (p less than 0.001). The mean villus height in the jejunal blind loop decreased by 30% (p less than 0.001). The demonstrated hypertrophic changes in the functioning part of the small intestine following jejuno-ileal bypass represent the morphological basis of functional intestinal adaptation. The effect of this adaptation is clearly shown in the characteristic weight diagram of an obese patient after bypass operation: the loss of weight cases, a period of stability ensues and then the patient begins to regain weight to some extent.

Humans↗
PubMed1975

Cell size and the antilipolytic effect of insulin in human subcutaneous adipose tissue.

Lipolysis was studied in subcutaneous adipose tissue removed under local or general anaesthesia from subjects with marked difference in body weight and from obese subjects before and after intestinal shunt operations. The release of glycerol was measured in sections of adipose tissue incubated for two hours in bicarbonate buffer containing 4 per cent bovine albumin with no glucose added. The larger fat cells were more insulin sensitive than the smaller. A positive relationship was observed between the fat cell size and the antilipolytic effect of insulin (100 muU/ml). Insulin had no significant effect on the lipolytic effect of the catecholamines, when this is calculated as the increment in the glycerol release above the basal.

Adipose Tissue↗
PubMed1975

Skin reduction plasties following intestinal shunt operations for treatment of obesity.

A unique group of more than 100 selected cases were treated surgically for massive obesity, a mal-absorption syndrome, by an intestinal shunt used to obtain significant weight reduction. The loss of skin elasticity of the slimming patient leads to a "redundant skin syndrome" creating dermatologic-cosmetic as well as psychiatric problems. A series of reductive skin plasties were performed beginning when the patient's body weight had been stable for some months. The redundant skin was found mainly in two contralateral areas: on both sides of the axillae: on the medial aspect of the upper arm and laterally below the breast, and on both sides of the inguinal ligament, on the lower abdomen and on the medial aspect of the thigh. Thirty-eight patients of the group had skin reduction plasties. The operations were performed on each site separately with a few months' interval. Operative techniques and results are presented.

Adolescent↗