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Biomedical subjects

A Apostolov

Publications and source records attributed to A Apostolov.

At least 19 recordsLinked to original sources
PubMed1991

Changes in the responsiveness of the colonic smooth muscle to carbachol in Hirschsprung's disease.

In vitro experiments were performed on smooth-muscle strips cut out in longitudinal and circular direction from the colon of Hirschsprung's patients who underwent an operation and from patients operated on for tumors of the sigmoid colon and rectum, serving as controls. The changes in the contractile activity of the smooth-muscle strips after carbachol applied cumulatively were examined and dose-response curves were plotted. The EC50 values for the circular strips from the aganglionic part of the colon were 6 x 10(-7) M in Hirschsprung's patients and 3.7 x 10(-8) M in control patients: the pD2 values were 6.23 and 7.43, respectively. This showed that the affinity of cholinoreceptors in the aganglionic part of the colon for carbachol was 16 times lower in Hirschsprung's patients as compared to control patients. The EC50 values for longitudinal strips from the ganglionic part of the colon were 2.6 x 10(-7) M in Hirschsprung's patients and 4 x 10(-8) M in control patients; pD2 values were 6.6 and 7.4, respectively. The affinity of cholinoreceptors in the smooth muscle of the ganglionic part of the colon for carbachol was also decreased (nearly 6.5 times) in Hirschsprung's patients as compared to controls.

Atropine↗
PubMed1990

[Postoperative invagination in early childhood].

Postoperative intussusception is a rare but serious complication which occurs usually during the early postoperative period with intermittent, but progressing intestinal obstruction with characteristic appearance of mucus-bloody stools. Two children with postoperative intussusception have been observed among 381 children who have had abdominal operations during the last three years (1985-1987) (0.5 per cent). Various postoperative complications developed in 45 children (11.8 per cent), in 2 of them (4.4 per cent) the complication being intussusception. Both children were operated for tumors. In one (1 1/2 years old) the postoperative intussusception was not diagnosed until it was re-operated; the child died. In the second child (3 months old) the postoperative intussusception was diagnosed by clinical and X-ray examination; the ileocolic portion of the intussusception was reduced by pneumocoloscopy, while the ileo-ileal required re-operation with manual reduction. The infant survived. Early diagnosis of this rare postoperative complication, especially when mucus-bloody stools appear and pneumocoloscopy is performed, is feasible. Appropriate treatment will help for a favourable outcome.

Child, Preschool↗
PubMed1986

Histochemical, immunocytochemical and ultrastructural data on the innervation of the smooth muscle of the large intestine in Hirschsprung's disease.

The frequency of occurrence of the adrenergic, cholinergic, 5-hydroxytryptamine (5-HT)-, substance P (SP)-, methionine-enkephalin (met-Enk)- and somatostatin (SOM)-immunoreactive fibres innervating the smooth muscle of the large intestine in Hirschsprung and control children was compared. It was observed a higher frequency of catecholamine-fluorescence, acetylcholinesterase-positive and SOM-immunoreactive fibres in the muscularis externa and muscularis mucosa of the aganglionic segment in Hirschsprung gut as compared to that in the sigmoid colon and rectum in controls. In contrast, the frequency of SP-, met-Enk- and 5-HT-immunoreactive fibres in the aganglionic segment in Hirschsprung gut was lower than that in the controls. Ultrastructurally the cholinergic and adrenergic fibres occurred more often in the aganglionic segment in Hirschsprung gut than in the controls. A treatment with 6-OHDA and a fixation by Tranzer and Richards technique was used to confirm the nature of the adrenergic fibres. The p-type fibres occurred infrequently in the aganglionic segment of Hirschsprung gut. The results suggest that the change in the frequency of the nerves containing inhibitory transmitters may play an important role in the pathogenesis of Hirschsprung's disease.

Adolescent↗
PubMed1986

Distribution of substance P-, methionine-enkephalin-, somatostatin- and serotonin-immunoreactive nerve elements of the large bowel in Hirschsprung's disease.

The distribution of substance P-, methionine-enkephalin-, somatostatin- and 5-hydroxytryptamine-immunoreactive nerve elements in Hirschsprung's disease was studied. It was compared to the distribution of the comparable nerve elements in the sigmoid colon and rectum of control children. A reduction of substance P-, methionine-enkephalin- and 5-hydroxytryptamine-immunoreactive fibers as well as a higher density of somatostatin-immunoreactive fibers were found in the aganglionic segment in Hirschsprung gut as compared to those in the ganglionic segment in Hirschsprung children and the large bowel in control children. The changes in the density of peptide- and 5-hydroxytryptamine-immunoreactive fibers suggest the participation of different transmitters or transmitter candidates in the pathogenesis of Hirschsprung's disease.

Child↗