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Biomedical subjects

D Kumar

Publications and source records attributed to D Kumar.

At least 37 records · Page 2Linked to original sources
PubMed1990

Allylamine and beta-aminopropionitrile-induced vascular injury: an in vivo and in vitro study.

Toxic cardiovascular effects of allylamine and beta-aminopropionitrile were studied in adult male Sprague-Dawley rats given allylamine alone (AA), 100 mg/kg/day, beta-aminopropionitrile alone (beta APN), 1 g/kg/day, or both chemicals (AA + beta APN) by gavage. Rats were given a total of 10 doses in 11 days. Rats given AA + beta APN showed extensive smooth muscle cell necrosis of the aortic media not seen when either toxin was given alone. Lingual artery lesions in the form of small intracellular eosinophilic globules were seen in animals given AA and AA + beta APN treatments, but were more numerous and larger in the latter group by morphometric analysis (p less than 0.03). Myocardial necrosis was much less severe in the AA + beta APN treatment group than in rats given only AA. A long-term follow-up (47 and 180 days) after the AA + beta APN protocol above showed that rats had persistent aortic medial necrosis with striking intimal cartilaginous metaplasia. Cultured porcine aortic smooth muscle cells exposed in vitro to combined AA and beta APN showed markedly decreased viability and increased cell injury when compared to cells exposed to only one toxin, thus supporting the synergistic toxic effect seen in vivo. Our studies show a synergistic necrotizing effect of AA and beta APN on aortic vascular smooth muscle cells. A hypothesis concerning these compounds' effects on vascular amine oxidases is made to explain this toxic synergism. Synergistic toxic interactions may be important in other forms of vascular injury.

Allylamine↗
PubMed1990

Evidence for motor neuropathy and reduced filling of the rectum in chronic intractable constipation.

Subtotal colectomy with ileorectal anastomosis is now frequently offered to patients with slow transit constipation who have severe symptoms and no response to more conventional medical treatment. If this operation is to be successful, the underlying problem should be delay in the progress of contents through the colon but no mechanical or functional obstruction in the small bowel or rectum. We have used a recently described technique of prolonged ambulant manometry and electromyography to investigate anorectal function in these patients. Pressure data were collected using a 2 mm diameter intrarectal probe carrying microtransducers, and external anal sphincter activity was assessed by a pair of silver-silver chloride surface electrodes. Fourteen control subjects and eight patients with colonic inertia were studied. Sampling reflexes, indicative of rectal filling, occurred at mean (SEM) rates of 7.4 (2.0)/hour in controls but were significantly reduced in patients (2.4 (0.3)/hour (p less than 0.01]. Recurrent rectal motor complexes were seen to occur in both groups at intervals of 76 (1.8) minutes in controls and 64.9 (7.2) minutes in patients (p less than 0.1), and with amplitudes of 42.4 (2.1) mmHg and 9.2 (0.7) mmHg (p less than 0.001), respectively. External sphincter electromyographic spike activity did not differ between groups. Our results support the concept of reduced transit of faeces to the rectum from the colon over a 24 hour period in slow transit constipation and suggest that a motor neuropathy may also be present in the rectum.

Adult↗
PubMed1990

Absence of synchrony between human small intestinal migrating motor complex and rectal motor complex.

Both the human small intestine and rectum exhibit motor activity in which relatively brief bursts of powerful regular contractions recur with a similar periodicity. We used prolonged ambulant manometry to test the hypothesis that these activities are synchronous. Pressure activity from the duodenojejunum and the rectum was recorded continuously for 24 h in eight freely ambulant healthy adults. A total of 61 migrating motor complexes and 61 rectal motor complexes occurred in the group; the median periodicities of the two rhythms differed significantly (P = 0.025). There was no evidence of synchrony between the two biorhythms. We conclude that they are independent oscillations.

Adult↗
PubMed1990

Relationship between enteric migrating motor complex and the sleep cycle.

To address the question of synchrony between two major biorhythms with a similar periodicity, the cortical rapid eye movement (REM)/non-REM sleep cycle and the enteric migrating motor complex (MMC cycle), we recorded upper small bowel motor activity and sleep activity during nocturnal and diurnal sleep in six healthy subjects. Motility was measured continuously using a fine (2.2 mm OD) and relatively comfortable nasojejunal probe with two pressure-sensitive microtransducers positioned under fluoroscopic control on either side of the ligament of Treitz. Sleep stages were recorded while the subjects slept in a sleep laboratory. Each subject was studied twice; once during normal nocturnal sleep and then after acute reversal of sleep by advancing the time of going to bed by 4 h each night for three nights. The total duration of sleep was similar for diurnal and nocturnal sleep. There was a significantly higher number of REM episodes (P less than 0.001) and REM sleep stage shifts (P less than 0.02) during diurnal (reversed) sleep. During sleep (both diurnal and nocturnal) there was a significant reduction in the MMC cycle length (P less than 0.02, P less than 0.03) and the duration of phase II of the MMC (P less than 0.009, P less than 0.02). The distribution of MMCs among sleep stages and REM sleep was consistent with a random distribution. These data show that periodic activity in the gut is modulated by the presence or absence of sleep, but they also are consistent with the hypothesis that the two cycles are independent and that one is not contingent upon the other.

Adult↗
PubMed1990

Role of psychological factors in the irritable bowel syndrome.

Our study was designed to test the hypothesis that psychoneurosis in irritable bowel syndrome (IBS) may be the secondary effects of the unsatisfactory nature of the medical transactions (diagnosis, explanation, prognosis, and therapy) in IBS rather than a primary cause of the syndrome. We carried out psychometric assessments on three groups of subjects: 10 healthy volunteers, 12 patients diagnosed as suffering from benign gastrointestinal disease, and 18 patients with IBS. We found a significantly raised incidence of psychoneurosis in IBS, but the components of this were predominantly anxiety and obsession; the incidence of depression in all 3 groups was similar. We argue that the data support our hypothesis that the psychoneurotic manifestations are secondary components of IBS; the data do not support the hypothesis that IBS is a manifestation of depression.

Adult↗
PubMed1990

Clinical evaluation of chandonium iodide as a nondepolarising muscle relaxant.

The effect of chandonium iodide (as a non-depolarising muscle relaxant) was studied in 50 patients of ASA grade I or II who were scheduled for surgery. The patients were divided into 2 groups according to the dose of chandonium iodide (0.2 and 0.25 mg/kg respectively). The onset and duration of action was found to be dose dependent. Intubation characteristics were good to fair in all the patients, the reaction to intubation being either absent or mild. There was mild and transient rise in pulse and blood pressure. No allergic reaction was observed in any patient and reversal characteristics were good in all the cases.

Adult↗
PubMed1990

Moebius syndrome.

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1989

Prolonged ambulant assessment of anorectal function in patients with prolapsing hemorrhoids.

Six patients with prolapsing hemorrhoids and 12 control subjects had assessment of anorectal pressure and external sphincter electromyography performed over a prolonged period under ambulant conditions. Patients with prolapsing hemorrhoids demonstrated greater degrees of sampling responses, 12.9 +/- 1.9/hour, vs. 7.4 +/- 2.0/hour (mean +/- SEM) in controls (P less than .05). Ultraslow wave and giant ultraslow wave activity were seen frequently in the patient group occupying more than 30 percent of recording. The external sphincter demonstrated much greater electrical activity (spike potentials) in patients with hemorrhoids than in controls both by day, 24.9 +/- 11.0/10 min vs. 12.8 +/- 3.2/10 min (P less than .02), and by night, 7.4 +/- 2.6 min vs. 1.6 +/- 1.3/10 min (P less than .03). Sleep electrical activity in the presence of hemorrhoids did not differ significantly from that of controls during waking, 7.4 +/- 2.6/10 min vs. 12.8 +/- 3.2/10 min (P less than .1). No difference in phasic and periodic rectal motor activity was noted between patient and control groups. This demonstrates the application of prolonged assessment of anorectal motility and external sphincter activity in a patient group. Abnormalities previously documented in patients with hemorrhoids using conventional manometric tests were confirmed. In addition, evidence of increased external sphincter function during waking and sleep may have implications in the pathophysiology of this disorder.

Action Potentials↗
PubMed1989

Human myenteric plexus: confirmation of unfamiliar structures in adults and neonates.

To define the myenteric plexus along the human gastrointestinal tract, we studied three neonatal and six adult specimens, postmortem, by silver impregnation. There were no clear differences between the neonatal and the adult gastrointestinal tracts. In the body of the esophagus, the plexus was sparse, with few ganglia; 30%-40% of fascicular intersections were devoid of ganglia. In the lower 5 cm, the esophagus had thick bundles of nerve fibers ("shunt fascicles"), which crossed the gastroesophageal junction and radiated to the periphery of the stomach through several branches. The plexus in the stomach was uniform, with intermediate and intrafascicular ganglia. A thick nerve bundle encircled the pylorus and gave branches on either side to the antrum and the duodenum. Shunt fascicles in the stomach did not cross the pylorus but extended to the distal antrum. In the duodenum and proximal jejunum, the plexus was regular, but in the mid-small intestine, the longitudinal interganglionic fascicles were more prominent than the circumferential fascicles. Distally, this pattern was reversed; circumferential fascicles were more prominent and ganglia were dense in the terminal ileum. Thin, short shunt fascicles were scattered along the entire small intestine, becoming more abundant in the terminal ileum. Short, thick shunt fascicles traveled proximally from the ileocecal junction for about 25-30 cm. As in the stomach, shunt fascicles did not cross the ileocecal junction, but a thick nerve bundle encircled it. In the cecum and proximal colon, the plexus was sparse with large intermediate and intrafascicular ganglia. In the rectum and distal colon, the plexus was dense, with parafascicular and intrafascicular ganglia. Long ascending nerves extended from the distal rectum into the midcolon. In addition, there were short, thick nerve bundles in the rectum that traveled proximally.

Adult↗
PubMed1989

Comparative evaluation of various immunodiagnostic tests for the diagnosis of Taenia solium cysticercosis in pigs, using fractionated antigens.

The sensitivity and specificity of double immunodiffusion (DID), indirect haemagglutination test (IHA), immunoelectrophoresis (IEP), counterimmunoelectrophoresis (CIEP) and enzyme-linked immunosorbent assay (ELISA) were evaluated and compared using saline extracted of Taenia solium larval scolex and its Sephadex G-200 fractionated 1st and 2nd peak as antigens. Various immunodiagnostic tests gave different results with different antigens. Highest sensitivity (92.5%) was obtained with 84.6% sensitivity was obtained with IHA and CIEP respectively using scolex antigen. CIEP gave better results as compared to IEP. Crude antigen gave high sensitivity but less specificity. It was concluded that CIEP can be used as a field test for the anti-mortem diagnosis and ELISA can be employed for laboratory confirmation of T. solium cysticercosis in pigs using fractionated 1st peak antigen.

Animals↗
PubMed1989

Subtotal cystectomy and antirefluxing hepaticoduodenostomy for choledochus cyst in children.

Total cystectomy with Roux-en-Y hepaticojejunostomy for choledochus cyst often causes malabsorption and other problems as a result of jejunal biliary diversion bypassing the duodenum. Restoration of near normal anatomy can only return the normal physiological harmony and assure normality. A simple antirefluxing hepaticoduodenostomy has proved successful.

Anastomosis, Roux-en-Y↗
PubMed1989

Fertility after orchiopexy for cryptorchidism: a new approach to assessment.

Fifty-six patients treated surgically for cryptorchidism between 1950 and 1975 were assessed for fertility. Their age at the birth of their first child was used as the parameter. A direct comparison with the normal population of different regions was available from the General Register Office of Scotland, obviating the need to use female statistics for comparison. The results showed that only very late surgical treatment of unilateral cryptorchidism affected fertility.

Adolescent↗
PubMed1989

Anorectal malformations with sacral bony abnormalities.

A range of anorectal malformations with sacral bony abnormalities was found in members from three generations of two kindreds. The anorectal anomaly was low in all but one of the patients. Partial sacral agenesis was the main bony defect in one family, and meningomyelocele and spina bifida occulta were noted in the second. The inheritance pattern in these kinships is autosomal dominant. This may be a variant of caudal regression syndrome, which seems to be aetiologically heterogeneous.

Abnormalities, Multiple↗
PubMed1989

Prolonged manometric recording of anorectal motor activity in ambulant human subjects: evidence of periodic activity.

Based on short recordings, the rectum has been shown to have contractions with a frequency of five to 10 cycles per minute and slow contractions at three cycles per minute. To define anorectal motility over a prolonged period of time, we have studied 12 healthy volunteers using a fine pressure sensitive anorectal probe. A total of 240 hours of recording was obtained. We observed three types of activity in the rectum: (i) runs of powerful phasic contractions with a frequency of two to three per minute, lasting for three to 10 minutes, and recurring to an interval of 92 (1.9) minutes (mean (SEM)) during the day and 56 (1.7) minutes (mean (SEM)) at night, (ii) isolated prolonged contractions lasting for 10-20 seconds and seen mainly during waking, and (iii) clusters of contractions occurring at a frequency of five to six per minute lasting for one to two minutes and seen predominantly during the postprandial period. These clusters of contractions resembled the discrete clustered contractions seen in the ileum, whereas the more powerful and prolonged runs of contractions resembled phase III activity in the small intestine. In contrast, the anal canal showed bursts of contractions which were not temporally related. Our data show that the rectum, like the upper gastrointestinal tract, exhibits periodic motor activity; it remains to be seen whether these two biorhythms are synchronous.

Activity Cycles↗
PubMed1989

Modulation of the duration of human postprandial motor activity by sleep.

We have measured the effect of the presence of food in the gastrointestinal tract on proximal small bowel motility during sleep. Motility was measured in eight healthy ambulant subjects using two strain-gauge microtransducers incorporated in a fine (2.5 mm OD) nasojejunal tube. The subjects ate a 540-cal evening meal (EM) on the first day. On the following day they ate an equicaloric meal (with similar proportion of carbohydrates, proteins, and fats) at lunch time (MM) and then another equicaloric late meal (LM) 15 min before going to bed. All subjects were asleep within 30 min of completing the LM. Postprandial activity was significantly (P less than 0.001) shortened after LM, but there was no difference in the postprandial motor activity after MM and EM. Migrating motor complex (MMC) cycle lengths were similar after MM, EM, and LM. There was no difference in the duration of phase II of the MMC cycle after MM, EM, and LM even though subjects were asleep during the MMC cycles after LM. The MMC propagation velocity after LM and EM was significantly (P less than 0.01, P less than 0.001, respectively) slower than the diurnal MMC propagation velocity after MM. In health, postprandial activity is diminished during sleep, whereas the consumption of a LM restores the phase II activity usually absent during sleep. A LM also abolishes the expected reduction in nocturnal MMC cycle length but maintains the circadian variation in the propagation velocity of the MMC cycle.

Adolescent↗