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Biomedical subjects

T Andersen

Publications and source records attributed to T Andersen.

At least 73 records · Page 4Linked to original sources
PubMed1993

Functional thrombin receptors on human T lymphoblastoid cells.

Human alpha-thrombin stimulated five different T lymphoblastoid cell lines to increase intracellular free Ca2+ concentrations, whereas five B cell lines did not similarly respond. The T cell intracellular free Ca2+ increased rapidly, plateaued within 10 to 20 s, and then declined without any measurable sustained intracellular free Ca2+ elevation. Liberation of inositol trisphosphate peaked within 60 s, and a rapid and sustained activation of protein kinase C was induced. The thrombin-specific inhibitor, hirudin, completely blocked the response to alpha-thrombin. Catalytically inactivated forms of alpha-thrombin failed to stimulate the T cells, whereas trypsin, gamma-thrombin (which lacks fibrinogen clotting activity), or the synthetic 14-amino acid thrombin receptor-activation peptide stimulated T cells, but required approximately 10-, approximately 15-, or approximately 100-fold higher concentrations, respectively, when compared to alpha-thrombin. Stimulation by thrombin receptor-activation peptide was desensitized by alpha-thrombin, and vice versa, but alpha-thrombin did not desensitize stimulation by mAb to the TCR/CD3 Ag. The presence of the receptor on T but not on B cells was confirmed by flow-cytometric analysis using a mAb against the human thrombin receptor. These findings demonstrate functional thrombin receptors on T lymphoblastoid cells that may be capable of activating the cells, independently of an ongoing immune response.

Amino Acid Sequence↗
PubMed1993

Cimetidine suspension as adjuvant to energy restricted diet in treating obesity.

OBJECTIVE: To study the effect of cimetidine suspension compared with placebo suspension on weight loss in moderately obese patients taking a 5 MJ/day diet supplemented with dietary fibre. To determine the relation between the effectiveness of the blinding and weight loss. DESIGN: Randomised double blind study with an eight week parallel group phase and a subsequent eight week crossover or continuation phase. SETTING: Outpatient clinic. SUBJECTS: 60 patients (51 women) aged 18-60. MAIN OUTCOME MEASURE: Weight loss. RESULTS: After eight weeks of treatment the mean weight loss in the cimetidine group (5.7 kg) was similar to that of the placebo group (5.9 kg; p = 0.78, 95% confidence interval -2.0 to 1.5 kg). Body mass index, waist and hip measurements, waist-hip ratio, and systolic and diastolic blood pressures decreased similarly in the two groups. No association was found between weight loss and the patients' ability to guess if they were being given drug or placebo. Correct guesses of current drug were more prevalent than expected by chance (25/37 correct, p = 0.05 for the parallel group phase; 26/30, p = 0.0001 for the crossover phase). CONCLUSIONS: Cimetidine had no effect on weight loss in moderately obese patients. The study underlines the potential problem that blinding of patients to treatment can be compromised.

Adolescent↗
PubMed1993

Correlation of primate red nucleus discharge with muscle activity during free-form arm movements.

1. We recorded from 239 neurons located in the magnocellular division of the red nucleus of four alert macaque monkeys. At the same time, we recorded electromyographic (EMG) signals from as many as twenty electrodes chronically implanted on muscles of the shoulder, arm, forearm and hand. We recorded EMG signals for periods ranging from several months to a year. 2. The monkeys were trained to perform three free-form food retrieval tasks, each of which activated all of the recorded muscles and most of the neurons. The 'prehension' task required simply that the monkey grasp a piece of food from a fixed point in space. The 'barrier' task required the monkey to reach around a small barrier to obtain the food, and the 'Kluver' task required that food be removed from small holes. During the prehension task, we found approximately equal numbers of neurons that were strongly active while the hand was being moved toward the target (70% of units), and while the food was being grasped (60%). Relatively few units were active as the hand was returned to the mouth (15%). 3. Data files of 1-2 min duration were collected while the monkey performed a single behavioural task. Whenever possible, we recorded files for all three tasks from each neuron. For each file we calculated long time-span analog cross-correlations (+/- 1.28 s) between instantaneous neuronal firing rate and each of the full-wave rectified, low-pass filtered EMG signals. We used the peak correlation and the time of the peak as two summary measures of the functional relation between modulation of neuronal activity and EMG. 4. The magnitude of the strongest correlations was between 0.4 and 0.5 (normalized to a perfect correlation of +/- 1.0). Distal muscles were the most frequently correlated, and extensors were more frequently correlated than flexors. For all monkeys, the lags for well correlated muscles were distributed broadly about a uni-modal value near 0 ms. Eighty five per cent of the correlations larger than or equal to 0.25 had peaks between -150 and 200 ms. 5. The activity of each neuron was represented in a muscle co-ordinate system by an n-dimensional 'functional linkage vector', each element of which was the peak correlation with one of n muscles. The vector for any given neuron points in a particular direction in muscle space, depending on the similarity between the activity of the neuron and the activity of each muscle.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1993

Bone metabolism in obesity: changes related to severe overweight and dietary weight reduction.

A non-invasive evaluation of bone metabolism was performed in 44 morbidly obese patients before and after a mean weight loss of 22.4 kg (range 7.9-43.4 kg) after 2 months and a further weight loss of 7.3 kg after 8 months (0.8-20.0 kg). This weight reduction was obtained by a nutritionally adequate very-low-calorie diet. Before treatment the bone mineral content of the distal forearm was increased compared to normals (51.9 U vs. 43.7 U, p < 0.001). Bone formation was evaluated by serum alkaline phosphatase and serum osteocalcin. Serum alkaline phosphatase was increased (187.8 U/l vs 147.4 U/l, p < 0.001) while serum osteocalcin was lower than in the controls (0.67 nmol/l vs 0.98 nmol/l, p < 0.01). Bone resorption, as measured by the urinary hydroxyproline/creatinine ratio, was not increased in the obese patients (19.2 molar ratio x 10(-3) vs 16.7 molar ratio x 10(-3), NS). After 2 months, the bone mineral content had declined by 3.3%. Serum alkaline phosphatase remained unchanged (187.8 U/l vs 186.9 U/l, NS) but serum osteocalcin demonstrated a significant rise (3.94 nmol/l vs 10.53 nmol/l, p < 0.001), parallel to changes in the hydroxyproline/creatinine ratio (19.2 molar ratio x 10(-3) vs 25.2 molar ratio x 10(-3), p < 0.001). At 8 months, no further change in the bone mineral content was seen. The hydroxyproline/creatinine ratio did still increase (from 25.8 molar ratio x 10(-3) to 30.1 molar ratio x 10(-3), p < 0.05), while serum alkaline phosphatase and serum osteocalcin remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Observer variation in measurements of waist-hip ratio and the abdominal sagittal diameter.

In an out-patient weight loss study of 63 patients (54 female, 9 male), 53 completed a 16 week treatment with a low calorie diet and a 9 g/day fibre supplement. In these 53 patients, the average weight loss was 8.3 kg (s.e.m. 0.8). Waist-hip ratio (WHR) and abdominal sagittal diameter (SagD) were measured as indicators of fat distribution and visceral adipose tissue (visceral AT) was estimated by anthropometric computerized tomography calibrated equations. Four observers measured WHR and SagD ten times in eight patients. Two dietitians examined the patients throughout the clinical trial at weeks 0, 4, 8 and 16. Furthermore, two physicians examined the patients at week 12 in the trial. Two- and three-way analyses of variance were performed to estimate the contribution of single factors to the total variance. The contribution of observers, 3.2% and 3.8%, respectively, was of the same magnitude as the error variance (2.9% and 4.8% respectively) which is a measure of the intra-observer variation. The two dietitians had very similar recordings and contributed only 0.3% and 0.9% to the total variance for WHR and SagD, respectively. The contributions of the two physicians to the total variance were 0.0% for WHR and 0.4% for SagD. It is concluded that there is no need to use several observers or repeated measurements of waist, hip and SagD in clinical anti-obesity trials.

Adipose Tissue↗
PubMed1993

Collagenous colitis: are bacterial cytotoxins responsible?

In a case of collagenous colitis, cholestyramine treatment resulted in symptomatic and histological normalization. After discontinuation of cholestyramine, collagenous colitis relapsed. At this time fecal cytotoxic activity was demonstrated in McCoy cell lines. Symptoms, histologic changes, and cytotoxicity disappeared when cholestyramine treatment was reinstituted. We hypothesize that a bacterial toxin is responsible for the development of collagenous colitis.

Aged↗
PubMed1992

[Over-the-counter weight-reducing preparations].

This report deals with over-the-counter products sold currently in Denmark for weight reduction. Only oral products (alternative medications and food supplements) are included. The report includes 35 such products. The aims of the report are to provide a common, factual basis for the debate about weight-reduction products and to present proposals for regulations that improve the conditions for patients and health professionals to make their choice of the optimal products. Current laws and administrative regulations are found to be complicated, obscure and inadequate. For most products, documentation for efficacy and safety is inadequate and health hazards are probable using several of the products. It is recommended 1) that obesity should be considered as a disease also in a legal/administrative context, 2) that an effective and objective registration of side-effects to alternative medication and food supplements is established, 3) that these products are tested for efficacy and safety before being marketed, 4) that the entire product information is made easily accessible, 5) that products without any documented effect are clearly labelled with this information and 6) that weight loss products involving health hazards are excluded from the market.

Denmark↗
PubMed1992

[Social conditions of hemophiliacs].

The objects of this investigation were 1. to describe the social conditions of haemophiliacs by means of questionnaires and to compare these with the population as a whole and 2. to investigate the social integration of haemophiliacs as assessed by type of family, occupation, club membership and contact with family and friends. The group investigated consisted of all Danish haemophiliacs with moderate to severe factor VIII and IX deficiency and cases of severe von Willebrand's disease. 64% replied (n = 135). Comparison by the age stratification with the population as a whole, showed that fewer haemophiliacs in the age group 25-44 years lived with partners and children and that more lived with their parents or alone. Haemophiliacs had a higher school education and more haemophiliacs were currently receiving occupational training. The occupational frequency was low for all age groups and more haemophiliacs had reduced working hours. The frequencies of contact with friends and family and access to practical assistance corresponded to that of the population as a whole. Social integration was correlated directly with school education and occupational training and satisfaction with contact with other people and inversely correlated with age, contact with social welfare offices and number of social payments received. Only a total of 6% of haemophiliacs were very poorly socially integrated.

Adolescent↗
PubMed1992

Metabolic changes during treatment with valproate in humans: implication for untoward weight gain.

This study was initiated to elucidate the mechanisms behind valproate-induced weight gain. Eight patients with epilepsy were studied with identical examination programs before and during the end of the first month of treatment with sodium valproate (VPA). The measurements included registration of food intake, indirect calorimetry, and determination of pancreatic and thyroid hormones, catecholamines, albumin, electrolytes, glycerol, and free fatty acids. Measurements were performed both at the basal condition and during a 3-hour oral glucose tolerance test (OGTT). After the start of VPA treatment, the mean levels during the OGTT of plasma glucose and catecholamines were significantly decreased by 7% and 25%, respectively (P less than .05). The mean ratio of insulin to glucagon decreased by 37% (P less than .01). During the glucose load, the decreases in free fatty acids were less pronounced after the start of VPA treatment, whereas the mean levels of glycerol were found to be unchanged. We detected no differences between the two periods with regard to total energy intake or macronutrient selection, energy expenditure, or thyroid hormones. As VPA is known to affect the concentration of carnitine in humans, it is hypothesized that a possible VPA-induced deficiency of the beta-oxidation of fatty acids is important for the development of obesity in epileptic patients in long-term treatment with VPA, but changes in catecholamines or other hormones might also be of importance.

Adult↗
PubMed1992

Liver and gallbladder disease before and after very-low-calorie diets.

Hepatobiliary characteristics of untreated obese patients and those of patients reducing weight through very-low-calorie diets (VLCDs) are reviewed. In untreated obesity, hepatobiliary abnormalities are prevalent. Fatty change is common and may be related to insulin resistance. Moreover, portal inflammation and fibrosis are prevalent findings, also in the absence of alcohol abuse. The liver plays a key role in the hyperinsulinism and hyperlipidemia, and hepatic drug metabolism is influenced by enhanced glucuronidation and sulphatation. Predisposition to gallstone formation can be ascribed to increased biliary cholesterol secretion in concert with changed nucleating factors and altered gallbladder motility. Weight loss by VLCD reduces fatty change but may induce slight portal inflammation and fibrosis. Insulin resistance and pharmacokinetic abnormalities regress. During VLCD the risk of gallstone formation is markedly increased. The deleterious effects described of a rapid weight loss should draw some attention to the liver and biliary tract during VLCD treatment.

Bile↗