Biomedical subjects
Publications and source records attributed to A Larsen.
In a series of 64 consecutive cases of transvesical prostatectomies it is shown that the use of a purse-string suture at the bladder neck significantly reduces the postoperative blood loss. A follow-up 3 months after operation has shown that the suture did not increase the number of either bladder neck stenoses, urinary incontinences, urinary infections or secondary lithiases.
The variation between four radiologists in the evaluation of hand, wrist, and foot radiographs of rheumatoid arthritis was examined. The recognition of individual radiologic changes varied considerably as judged by the findings of the different observers. Erosion and joint space narrowing were interpreted more uniformly than soft tissue swelling and osteoporosis. When the radiographs were graded from 0 to 5 using standard reference radiographs, more than 90% of them were graded uniformly or with a difference of only one grade. The investigation has shown that when applying grading of rheumatoid arthritis according to standard reference radiographs, the interobserver variation is considerably less than when pure individual radiological changes of rheumatoid arhtritis are considered.
Muscles of the lower legs of rats given 25% ethanol in water ad libitum for up to 9.5 months were studied using histological, histochemical and electrophysiological techniques. Ethyl alcohol was substituted for about 20% of the total calorific input of the animals. The observations were compared with the structure of the gastrocnemius muscle of five alcoholics with clinical neuropathy. Fibrillation potentials and angulated atrophic fibers were observed in the muscles of animals on alcohol for 9.5 months. No fiber type grouping was present. There was also phagocytosis of the muscle fibers and changes in their internal structure, as reflected by the distribution of NADH-diaphorase. The observed muscle changes in the alcoholics and those in the experimental animals on alcohol differed mainly quantitatively, the only exception being the presence of fiber type grouping in the biopsies from the alcoholics.
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Human visual recognition on the basis of shape but regardless of size was investigated by reaction time methods. For successive matching of random figures, reaction time increased linearly with the linear size ratio of stimulus pairs. For single-character classification, reaction time increased with divergence between cued size format and stimulus format such that for character nonrepetitions, the increment in latency was approximately proportional to the logarithm of the linear size ratio of the two formats. However, when reactions to character repetitions were faster than those to nonrepetitions, the repetition reaction time function was similar to that for successive matching of random figures. The results suggested two processes of size scaling: mental-image transformation and perceptual-scale transformation. Image transformation accounted for matching performance based on visual short-term memory, whereas scale transformation accounted for size invariance in recognition based on comparison against visual representations in long-term memory.
The effects of pindolol and sotalol on neuromusclar transmission were tested using intracellular microelectrode recording of resting membrane potentials, miniature end-plate potentials and end-plate potentials, and recording of muscle contractions upon nerve stimulation of rat phrenic nerve-hemidaphragm preparations. Both pindolol and sotalol reduced the amplitudes of miniature end-plate potentials and end-plate potentials in a dose-dependent manner without significantly affecting their time-courses. Pindolol, but not sotalol, also increased the frequency of the miniature end-plate potentials and decreased th number of acetylcholine quanta released by nerve impulses. Neither of the drugs significantly affected resting membrane potentials of the muscle fibres or excitability of the motor nerve to electric stimulation.
Muscle action potentials and miniature end-plate potential frequency were studied in different concentrations of pindolol, d- and l-propranolol and sotalol using intracellular microelectrode recording from rat phrenic nerve-diaphragm preparations. d-and l-propranolol at concentrations of 10 to 40 mg/l and pindolol at 20 to 100 mg/l slowed down the rate of rise, prolonged rise and half-decay times and reduced the overshoot of the muscle action potentials. Sotalol had similar effects but only at higher concentrations (100 to 200 mg/l). The drugs had no effect on the increase in the miniature end-plate potential frequence obtained with depolarization by increased extracellular potassium concentration.
DNA-synthesizing cells from the rheumatoid arthritis synovial tissue of 7 patients and from 5 patients with traumatic and degenerative joint lesions were studied by incubating fresh synovial tissue samples with tritiated thymidine. Labelled cells were identified using autoradiography. The tissue sections were stained with methyl green pyronine. It was found that 0.66% (range 0.38-1.4) of the cells were labelled with 3H-thymidine whereas in control materials the percentage was 0.17 (range 0-0.38). Approximately half of the labelled subsynovial cells in rheumatoid patients (range 37-67%) were small lymphocytes, according to morphological criteria. About one-tenth of the labelled cells (range 0-17%) looked like medium-sized lymphocytes, while the rest had the characteristics of fibroblasts or were unidentifiable.
Single aortic valve replacement was performed in 110 patients at Ullevål Hospital, Oslo, between 1971 and 1976. The follow-up period was 1 to 6 years (mean 31 months). The early postoperative mortality was 6.3% and the late mortality 8.2%. Postoperatively 44% of the surviving patients were in the N.Y.H.A. functional class I and 55% in class II, while 71% of the patients were in class III or IV pre-operatively. Objective evidence of improvement was shown by reduction in mean heart volume from 610 ml/m2 pre-operatively to 512 ml/m2 postoperatively (p less than 0.001). Electrocardiographic signs of left ventricular hypertrophy, measured as the combined voltage of Smax and Rmax in V1 to V6, were 56mV pre-operatively and 42 mV postoperatively (p less than 0.001). Myocardial failure was the main cause of death postoperatively. Sudden death occurred in 5 of the 9 patients in the late mortality group. Old age at the time of operation (65 to 71 years) was not associated with increased risk of death and complications, while alcoholism did increase the mortality rate.
Five patients with delayed cold urticaria are described. The urticarial skin response was present between 24 and 72 hours after ice challenge. In two of the patients the cold sensitivity was of clinical relevance. Some of the patients displayed low alpha1-antitrypsin and increased C4 levels in their serum. Our findings may justify the introduction of cold provocation as a routine procedure in the investigation of a patient with chronic urticaria.
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Rats were given daily injections of 0.2 or 0.5 g/kg chlorophenoxyisobutyrate (clofibrate) for 9 to 46 days. Lower leg muscles were studied with light and electron microscopy. Daily treatment with 0.5 g/kg of the drug for 26--46 days caused myopathic changes.
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A review of radiographic evaluation of rheumatoid arthritis is given. Standard reference films are introduced for evaluation of rheumatoid arthritis and related conditions in the extremity joints. In this system, numerical evaluation of arthritis is given for individual joints in a patient.
The effects of 120 mg propranolol and 15 mg pindolol daily on positional tremor of 24 patients with benign essential tremor were analyzed with a double-blind crossover trial and electrical tremor recording. Compared with the placebo effect, tremor amplitude was smaller under propranolol and larger under pindolol, whereas the frequency did not change.