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Biomedical subjects

K Carlsson

Publications and source records attributed to K Carlsson.

49 records · Page 3Linked to original sources
PubMed1988

Three-dimensional reconstruction of neurons in the lamprey spinal cord in whole-mount, using a confocal laser scanning microscope.

When investigating the detailed morphology of nerve cells, three-dimensional structural information is often of great value. We present here a technique by which 'optical sectioning' and three-dimensional reconstruction of fluorescence-labelled neurons in the lamprey spinal cord has been performed by means of a confocal microscope scanner with a laser beam as the light source. In confocal microscopy only a small spot of the specimen is being illuminated at any one time, and only light from the illuminated spot is detected. This gives several advantages compared with traditional microscopy: (1) Lateral resolution is improved, and any 'halo' effects occurring around structures with intense fluorescence are drastically reduced. In addition (2), a unique depth resolution is obtained due to the strong attenuation of structures that are out of focus. This allows the system presented here to (3) perform a detailed three-dimensional computer reconstruction of the neuron, without any need for physical sectioning of the tissue. The volume of data points sampled can subsequently be treated in various ways, including selection of different viewing angles, enhancement of contours, and background suppression.

Animals↗
PubMed1988

Gastrin and somatostatin in the rat antrum. The effect of removal of acid-secreting mucosa.

Female rats were subjected to operations aimed at reducing the amount of oxyntic gland mucosa draining its acid secretion to the antrum. The rats were provided either with Heidenhain or Pavlov pouches reducing the oxyntic mucosa draining its secretion to the antrum by about 50% or subjected to various degrees (75, 90 and 100%) of fundectomy. Ten weeks following surgery, plasma levels of gastrin and somatostatin were assayed. At the same time, antral mucosal content of gastrin and somatostatin was determined as well as the mucosal density of these hormone-producing cells. There was a relationship between the amount of acid-secreting mucosa removed and the ensuring plasma concentration of gastrin. Thus, a stepwise increase in plasma gastrin was found with the highest levels obtained in rats subjected to 90 or 100% fundectomy. The somatostatin concentration in plasma was reduced only in rats subjected to fundectomy with the most sustained decrease in animals in which all oxyntic gland mucosa had been removed. There was also a relationship between the amount of acid-secreting mucosa removed and the gastrin content of the antral mucosa. An inverse relationship seemed to exist between antral gastrin and somatostatin concentrations. However, a significant decrease in somatostatin concentration of the antral mucosa was seen only in rats subjected to a fundectomy. The number of gastrin cells in the antral mucosa was increased in fundectomized rats only, with the largest density seen in rats deprived of all oxyntic mucosa. A corresponding decrease in the number of somatostatin cells was noticed. Our results would suggest an apparent functional relationship between antral gastrin and somatostatin cells, where the antral acid load (or pH) appears to be the major factor of physiological significance.

Animals↗
PubMed1988

An epitope in Coil 2B of cytokeratin 8.

An immunological epitope has been located at the well preserved heptade discontinuity in Coil 2B of human cytokeratin 8, with the aid of synthetic peptides, antibodies to these and monoclonal antibodies to cytokeratins. CD revealed 37% alpha-helix in a 31-peptide.

Animals↗
PubMed1987

Beta-adrenoceptor blockade in the treatment of postoperative adynamic ileus.

Abdominal trauma, such as surgery and peritonitis, leads to inhibition of intestinal motility, partly mediated by alpha- and beta-adrenoceptors. To investigate the effect of nonselective beta-blockade on adynamic ileus, propranolol was compared with placebo in the postoperative course after elective colonic surgery in a double-blind randomized study. Ten patients received 4 mg propranolol intravenously twice daily, and ten received 10 mg intravenously twice daily. Nineteen patients received placebo. The time to first passage of stool was 110 +/- 9 h in the placebo group and 82 +/- 11 h in the 4-mg propranolol group. In the 10-mg propranolol group, the time was 79 +/- 8 h. The difference between the placebo-treated group and the propranolol-treated groups was significant (p less than 0.01). The effect of propranolol was most marked in older patients and after surgery on the distal colon. In patients older than 60 years the time to first stool in the placebo group was 127 +/- 13 h (n = 8), compared with 73 +/- 8 h (n = 11) in the propranolol group (p less than 0.01). In patients who had undergone surgery on the distal colon the time to first stool was 125 +/- 13 h (n = 8) in the placebo group and 76 +/- 8 h (n = 11) for propranolol (p less than 0.01). Adverse effects on the respiratory or cardiovascular system were not seen during medication. It is concluded that propranolol shortens the period of adynamic ileus after colonic surgery.

Adult↗
PubMed1976

The effect of an occlusal interference on the masticatory system. An experimental investigation.

An experimental short term study on the effect of an occlusal interference on the path of closure of the mandible was carried out on 8 persons. The interference consisted of a gold inlay placed unilaterally in one of the mandibular first molars. Clinical and electromyographic studies revealed functional disturbances or pain in all subjects. The masticatory musculature was tender to palpation and showed coordinational disturbances; the TMJ showed tenderness to palpation, clicking and irregular movements and the interfering teeth periodontal tenderness.

Adult↗
PubMedDate not supplied

Scuba diving accidents in Sweden 1960--1976.

Thirty "scuba" diving accidents (29 of them fatal) which occurred in Sweden during 1960--76 are listed. Nine of these are described in some detail. The probable causes of these accidents are evaluated, and suggestions for prophylactic measures are made.

Accidents↗
PubMedDate not supplied

Physical interpretation of diaphanograms using the computer-controlled image scanner OSIRIS.

Experiments have shown that the light recorded in diaphanography covers approximately the wavelength region of 645 to 900 nm. No significant change in image quality was noted by changing the camera distance between 10 and 25 cm and the light source aperture between 5 and 30 mm. Experiments using polarising filters indicated that the breast is optically isotropic; therefore the results cannot be improved by using polarising filters. In a comparison of various films. Kodak Ektachrome Infrared Film gave the best results. No degradation or variation in image quality was observed when different batches were compared or when the exposed film was stored for 3 weeks before processing. The exposure level is a critical factor and a series of 3 images is needed for optimum evaluation of diaphanograms. The experiments indicate that diaphanography gives consistent results.

Adult↗
PubMedDate not supplied

Breast carcinoma and benign breast lesions. Diaphanography and quantitative evaluation using the computer-controlled image scanner OSIRIS.

A total of 110 diaphanograms from women with breast carcinoma and 154 diaphanograms from women with benign breast disorders were quantitatively evaluated using the OSIRIS image scanner. Optical density values in the green and red spectral bands were recorded. The malignant and the benign groups, were statistically evaluated using linear discriminant analysis. Correct classification was obtained in 73.5 per cent of women with breast carcinoma and in 84.6 per cent of women with benign breast disorders. Visual interpretation of the findings alone classified 84.5 per cent of the malignant lesions correctly and 90.8 per cent of the benign lesions correctly. Quantitative evaluation combined with visual interpretation improved the accuracy of classification of breast carcinoma (91.8%), but not of benign breast disorders, which was about the same (83.8%).

Analog-Digital Conversion↗