Search PubMed⌕ Search

Biomedical subjects

J Jing

Publications and source records attributed to J Jing.

61 records · Page 4Linked to original sources
PubMed1990

Postprandial colonic transit and motor activity in chronic constipation.

The aim of this study was to correlate colonic motility and transit in patients with constipation and symptoms of the irritable bowel syndrome. Studies were performed in 16 patients with constipation and compared with the results in 12 healthy subjects. Intraluminal pressure was measured with perfused catheter ports in the transverse colon, splenic flexure, and descending and sigmoid colon. Movement of the luminal contents was measured by following the movement of Technetium-99m-DTPA that was instilled as a bolus in the splenic flexure. In both healthy subjects and patients with constipation there was no movement of the intraluminal tracer and no increase in intraluminal pressure during fasting. After eating a meal, healthy subjects and one group of the constipated patients had an increase in the radioactive marker in the transverse colon (p less than 0.03) and in the sigmoid colon (p less than 0.03). The movement of the intraluminal contents was associated with a positive pressure gradient between the descending colon and the transverse and sigmoid colon. There was no retrograde movement of the intraluminal contents and no postprandial increase in intraluminal pressure in the second group of patients with constipation. In healthy subjects, propagating contractions, which were associated with the rapid movement of intraluminal contents, began 60 min after eating. There were no propagating contractions in patients with constipation. These studies suggest that (a) the movement of intraluminal contents in healthy and constipated patients is determined by the postprandial pressure gradients within the colon, and (b) the propagating contraction is necessary for a normal bowel habit.

Adult↗
PubMed1990

[A microcomputer processing system of evoked potentials of brain slices and applied examples].

Processing the evoked potentials of neurons with a computer can greatly increase the efficiency of data processing and obtain much more information from the data. Besides, it renders possibility of large quantities and prolonged observation. In this system, DMA mode is used for data transfer from A/D card to the computer, so total processing program including sampling subroutine was made in BASIC language. This article introduces the functions of this program in processing data and the technique in making this program.

Brain↗
PubMed1989

Association between postprandial changes in colonic intraluminal pressure and transit.

The aim of this study was to correlate the movement of colonic luminal contents with the changes in intraluminal pressure. Studies were performed in 9 healthy volunteers. Intraluminal pressure was measured with perfused catheter ports in the transverse, splenic flexure, descending, and sigmoid colon. Movement of the luminal contents was measured by following the movement of technetium 99m-ethylenetriamine-pentaacetic acid that was instilled as a bolus in the splenic flexure. During fasting there was very little change in pressure or in the movement of intraluminal contents. After eating a 1000-kcal meal, the tracer moved from the splenic flexure into the transverse colon and the sigmoid colon. Nonpropagating colonic motor activity increased in all colonic segments immediately after eating the meal (p less than 0.05). The increase in motility was significantly greater in the descending colon than in the transverse and sigmoid colon (p less than 0.05). In one-half of the subjects propagating contractions occurred postprandially. The movement of the intraluminal tracer occurred during both types of motility. The nonpropagating contractions were associated with a gradual movement of the luminal contents. The direction of the movement of the contents was determined by the differences in pressure in the different segments of the colon. The propagating contractions were associated with a rapid movement of intraluminal contents. These studies suggest that (a) colonic motility and transit are quiescent during fasting and (b) the transverse colon acts as a mixing and storage area, as retrograde transit into the transverse colon is the characteristic postprandial pattern.

Adult↗
PubMed1989

Development of calcium channels in gastric smooth muscle.

We used [3H]nitrendipine to characterize dihydropyridine sensitive calcium channels on cells isolated from neonatal (1 d) and weanling (11 wk) rabbit gastric fundic and antral smooth muscle. Incubating with and without nifedipine 20 microM, specific binding was 56 +/- 4% of total binding at 0.1 nM [3H]nitrendipine. Specific binding was saturable, reversible, achieved equilibrium by 10 min at 4 degrees C, and was linearly related to cell concentration. The affinity constant for [3H]nitrendipine was higher in weanling fundus (kd = 243 +/- 121 pM) versus antrum (kd = 771 +/- 190 pM), p less than 0.05. There were no age-related changes in affinity. In the antrum, the number of binding sites (Bmax) increased from 6,000 +/- 266/cell in neonates to 27,500 +/- 8,440/cell in weanlings (p less than 0.05). In the fundus Bmax was 7,750 +/- 2,100/cell in neonates, and there was no age-related change. To assess function, we compared isometric stress in full thickness muscle strips oriented to the circular layer. Bethanechol stimulated dose-dependent tonic contractions in the fundus and phasic contractions in the antrum. Maximal stress increased with age from 305 +/- 54 mN/cm2 to 1140 +/- 73 mN/cm2 (p less than 0.05) in the fundus and from 72 +/- 20 mN/cm2 to 154 +/- 30 mN/cm2 (p less than 0.05) in the antrum. Preincubation and incubation without calcium resulted in reversible inhibition of contraction at both ages. Nifedipine 10-microM inhibited 100% of bethanechol-stimulated contraction in the antrum, but only 25% in the fundus at both ages.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Development of the muscarinic receptor in rabbit gastric smooth muscle.

We used binding of [N-methyl-3H]scopolamine ( [3H]-NMS) to tissue homogenates and isometric contraction of muscle strips to characterize perinatal changes in the muscarinic receptor on rabbit gastric smooth muscle. In homogenates from fetal (28 days of gestation), 1-, 3-, and 7-day, 4- and 11-wk-old rabbits, specific binding was saturable and temperature dependent, achieved equilibrium by 10 min at 30 degrees C, and was linearly related to tissue concentration. Specific binding was 80 +/- 2% of total binding at 0.2 nM [3H]NMS. The number of binding sites was 120,000 receptors/cell, maximal during the first week of life compared with the fetus or older animals. Affinity of [3H]NMS was highest in the first week of life (Kd = 345 +/- 24 pM, 1 day old). Age did not affect Hill coefficients or Ki values; secoverine and 4-diphenylacetoxy-N-methylpiperidine methiodide were 50-fold more potent than pirenzepine. In muscle strips, bethanechol stimulated dose-dependent atropine-inhibitable isometric contraction. The doses required for half-maximal contraction were similar in both age groups (5-6 microM), but maximal contraction was fivefold greater in weanlings compared with neonates. Increasing extracellular potassium concentration resulted in similar differences, suggesting that the differences were not receptor related. These results suggest that well-differentiated M2-muscarinic receptors are functional on rabbit gastric smooth muscle during the perinatal period.

Animals↗
PubMed1979

Risk factors for cancer of the testis in young men.

An individual matched case-control study of testis cancer in 131 men under age 40 was conducted to investigate antecedent risk factors including events during prenatal life. Ten patients were born with an undescended testis compared to only two controls (p less equal to 0.02), a previously reported risk factor. Two new risk factors were uncovered: six patients-mothers received hormones during the index pregnancy compared to only one control-mother, and eight patient-mothers and two control-mothers reported excessive nausea as a complication of the index pregnancy. A hypothesis linking these three factors is presented: viz, that a major risk factor for testis cancer is a relative excess of certain hormones (in particular estrogen) at the time of differentiation of the testes.

Adolescent↗