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Biomedical subjects

S Sood

Publications and source records attributed to S Sood.

At least 145 records · Page 8Linked to original sources

Blood-brain barrier transport and cerebral utilization of dopa in living monkeys.

[18F]fluoro-dopa, DL-3,4-dihydroxy-5-[18F]fluorophenylalanine, a tracer for dopa, was injected intravenously into cynomolgus monkeys anesthetized with enflurane, and the appearance of 18F in the head and the disappearance of 18F from the blood were each measured continuously for 10 min with simple gamma-ray detectors. A three-compartment explanatory model was used to derive fractional rate constants for the forward flux of L-dopa into the endothelium of the brain capillaries from the blood (1.54 +/- 0.37 min-1), the back flux of dopa and/or its metabolites to the blood from the endothelium (0.67 +/- 0.05 min-1), the formation of dopamine from dopa (0.20 +/- 0.04 min-1), and the destruction of dopamine (0.04 +/- 0.02 min-1). It was also shown that only one-fifth of the dopa that entered the endothelium was available for dopamine synthesis in neurons. It was concluded that the technique described could be extended to man and used to investigate the role of dopa and dopamine in the control of mood and locomotion.

Animals↗

A controlled evaluation of orally administered aspirin, dipyrone and placebo in patients with post-operative pain.

A double-blind controlled trial was carried out in 267 patients with moderate to severe pain following episiotomy to compare the pain relief provided over a 6-hour period by a single oral dose of 500 mg dipyrone, 500 mg aspirin or placebo. The results showed that dipyrone and aspirin were both significantly superior to placebo. Pain relief with dipyrone was already apparent at 30 minutes after drug intake, and was of significantly longer duration than that of aspirin. No side-effects were reported.

Administration, Oral↗

[18F]fluoro-dopa, an analogue of dopa, and its use in direct external measurements of storage, degradation, and turnover of intracerebral dopamine.

3,4-Dihydroxy-5-fluorophenylalanine, fluorodopa, was injected into rats in which unilateral lesions of the nigrostriatal pathway had been made. The rats rotated towards the side with the lesions, thus providing further evidence that fluoro-dopa is an analogue of dopa. [(18)F]Fluoro-dopa was then injected intravenously into fully conscious baboons. A well-collimated scintillation detector, aligned along the occipitomental axis, recorded the accumulation of (18)F in the brain. Control animals accumulated (18)F continuously for 100 min. This accumulation represents net transport of [(18)F]fluoro-dopa from blood to brain, decarboxylation to [(18)F]fluoro-dopamine, storage, and degradation of [(18)F]fluoro-dopamine. alpha-Methyl-dopa, a competitive inhibitor of dopa transport and decarboxylation, prevented the accumulation of (18)F; reserpine, known to release stored intracerebral dopamine, discharged (18)F; pargyline, a monoamine oxidase inhibitor, and haloperidol, a known augmentor of intracerebral dopamine turnover, increased the rate of accumulation of (18)F. These changes in the accumulation of intracerebral (18)F, after [(18)F]fluoro-dopa, were commensurate with the known action of the drugs used to induce them and demonstrate the use of a gamma-emitting precursor of a neurotransmitter to monitor simply, atraumatically, and externally the intracerebral metabolism of the transmitter in fully conscious primates. When applied to man, the same technique should be able to provide more conclusive evidence than is presently available for the role of catecholamines in schizophrenia and depression. It should also provide further insight into the natural history of nigrostriatal diseases and the action of drugs used in their treatment.

Animals↗

Stricture-plasty for tubercular strictures of the gastro-intestinal tract.

Twenty stricture-plasties have been performed for multiple tubercular strictures of the gastro-intestinal tract in 9 patients, who in total had 35 strictures. The procedure has been found to be safe, simple and effective in relieving obstructive symptoms. It does not appear to carry the disadvantages of entero-anastomosis or multiple and/or massive resections in cases of multiple tubercular strictures of the small bowel.

Adult↗

Catheter duodenostomy for perforated duodenal ulcer.

A new technique of catheter duodenostomy is described as treatment for a large perforated duodenal ulcer in a patient who came to the hospital seven days after the perforation. The problem of gastric stasis due to pyloric obstruction was tackled by gastrostomy. Nutritional needs of the patient were met by feeding through the duodenostomy catheter.

Aged↗

Increased plasma protein binding and lower metabolic clearance rate of aldosterone in plasma of low cortisol concentration.

During ACTH or cortisol infusion in ten recumbent normal men taking dexamethasone, the metabolic clearance rate of aldosterone increased by 50% as plasma cortisol was raised from low (2 mug/dl) to high concentration (50 mug/dl). Since splanchnic blood flow did not change, a greater efficiency of removal of aldosterone must have occurred, by means of displacement of aldosterone from high-affinity sites on plasma protein. At 37 C, equilibrium dialysis of low-cortisol plasma showed one-third of plasma aldosterone bound to albumin, and 24 to 28% bound to higher-affinity sites on other protein. As plasma cortisol increased, a progressively smaller fraction was tightly bound, approaching zero as transcortin was saturated with cortisol. The addition of large amounts of aldosterone to low-cortisol plasma displaced 14C-cortisol from transcortin binding sites. The results support earlier evidence that a significant fraction of plasma aldosterone is bound to transcortin, from which it is readily displaced by cortisol, resulting in an increased metabolic clearance rate of aldosterone by making a larger fraction available for removal from plasma.

Adrenocorticotropic Hormone↗

Amebic peritonitis.

A total of 18 patients with amebic peritonitis were studied. Fourteen of these cases were due to rupture of amebic liver abscess into the peritoneum and the remaining cases were due to perforation of amebic colitis. No initial suspicion of amebic etiology was made in more than half of the cases. In the group of ruptured liver abscesses, nearly half of the patients showed right lower lung syndrome. The diagnosis in 13 of 14 cases of rupture of liver abscess was confirmed on aspiration. Patients with ruptured amebic liver abcess were of two types: 1. Diffuse type with diffuse signs, shorter duration of illness and poor prognosis. 2. Localized type with longer duration of illness, marked signs of peritonitis and better prognosis. Once the diagnosis of peritonitis was made, the management was surgical. Conservative treatment was tried only in cases with signs of localization. The mortality rate had been 33% in amebic liver abscess rupturing into the peritoneum and 75% in perforation of the intestine. A high index of suspicion of amebiasis in patients with an acute abdomen and institution of early treatment are recommended to help in reducing this mortality. Amebic liver abscess and amebic dysentery should be treated energetically to avoid this fatal complication and surgical intervention whenever indicated should not be delayed.

Adult↗