Biomedical subjects
D Kumar
Publications and source records attributed to D Kumar.
Thermodynamics of spin glasses in the Hartree-Fock approximation.
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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.
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.
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.
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.
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.
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.
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.
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.
Pancreatic nesidioblastosis in adults.
Nesidioblastosis, a condition characterized by diffuse islet cell hyperplasia arising from the ductal epithelium, is often associated with hyperinsulinemic hypoglycemia. This is a childhood disease and is rarely found in adults. Only 10 histologically proven cases have been recorded, including 3 new cases described in this article. Most clinical and biochemical features are identical to those of an insulinoma, except the proinsulin-like component of circulating immunoreactive insulin, which is usually within the normal range in nesidioblastosis. Limited observations show that some patients may be managed medically with diazoxide. Patients who remain hypoglycemic despite medical therapy require pancreatectomy, although greater than 90% resection frequently results in insulin dependency and permanent diabetes.
Analysis of somatic changes in human tumor DNA using synthetic oligonucleotide probes.
Like most hematologic malignancies, solid cancers may be associated with non-random chromosomal abnormalities. Heterogeneity in the cell population in solid cancers and the chromosomal variations occurring among primary, explant, and passaged cells of a given tumor, however, present a major difficulty in assessment of their cytogenetic changes. Alternative approaches to identifying specific somatic changes in subtypes of solid cancers, without cell culture manipulations, must be developed. This report describes preliminary evidence indicating that oligonucleotide probes, homologous to short tandem repeats, that can determine individual identity, may also be useful tools with which to examine somatic changes in DNA which has been isolated directly from a tumor mass. Two, of the four, bladder tumors (transitional cell carcinomas) analyzed, exhibited oligonucleotide-based DNA fingerprint patterns that differed from those of corresponding constitutive or uninvolved tissue DNA. The changes that were observed included gain or loss of hypervariable DNA fragments or shifts in band intensities.
Early onset hereditary spinocerebellar ataxia: an autosomal recessive disorder distinct from Friedreich's ataxia.
The important clinical features of seven patients with an early onset slowly progressive heredofamilial spinocerebellar degenerative disorder of probably autosomal recessive inheritance included limb ataxia, retained and/or exaggerated tendon reflexes (biceps and knee), pyramidal weakness of lower limbs and normal sensory action potentials. This rare disorder is probably distinct from Friedreich's ataxia and carries a better prognosis.
Relaxation and transition in general Huberman-Kerszberg models: A recursive variational method.
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Ivermectin in equine lichen tropicus.
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Gastro-oesophageal reflux and intestinal malrotation in children.
In a series of 74 children undergoing Nissen fundoplication for persistent gastro-oesophageal reflux unresponsive to intensive medical treatment, there was an unexpectedly high incidence (54 per cent, n = 40) of intestinal malrotation. The series was not homogeneous, 25 of the children having reflux as a complication of a serious congenital abnormality (48 per cent incidence of intestinal malrotation), and 49 presenting with 'idiopathic' reflux (57 per cent incidence of intestinal malrotation). Intestinal malrotation is best detected pre-operatively by careful barium radiology, requiring clinicians to be aware of the association. In our experience, in children over the age of 3 months, both an antireflux operation and Ladd's procedure are often necessary to stop gastro-oesophageal reflux when an intestinal malrotation is present.
Type-specific concordance in young diabetic monozygotic twins.
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Reflux from ileum to colon in the dog. Role of external ligamentous attachments.
In four dogs we quantified the role of external ("coloileal") ligaments in preventing coloileal reflux. All animals were tested under control conditions, and then two had all external ligamentous attachments between ileum and colon divided; the other pair underwent a sham operation. Coloileal reflux was quantified scintigraphically at colonic pressures of 20, 40, and 60 mm Hg, and ileal motility was recorded concurrently. During control experiments and after sham operations, no dogs showed coloileal reflux at colonic pressures of 20 and 40 mm Hg. At a colonic pressure of 60 mm Hg, two control experiments and one in a dog after sham operation resulted in reflux of 9%, 4%, and 8% of counts, respectively. In contrast, both test dogs (after division of the ligaments) refluxed 30-70% of colonic content in all of four experiments at pressure below 20 mm Hg. In control dogs and in those with a continent ileocolonic junction, ileal motility consisted of scattered clusters of phasic contractions. In dogs with coloileal reflux, these clusters occurred with a similar frequency, but they lasted longer (P less than 0.005). Four weeks later, ileal motility indices in control dogs were significantly less (P less than 0.02) than in animals with divided coloileal ligaments. These observations establish an experimental model for coloileal reflux, support the hypothesis that external ligamentous attachments help maintain continence at the ileocolonic junction, and imply that coloileal reflux changes the motor pattern of the terminal ileum.