Biomedical subjects
Publications and source records attributed to K Singh.
Hereditary angioedema is a well defined entity for which we now have effective therapy. It is a condition however that can have different clinical presentations which require individualized therapeutic approaches. The recent advances into the molecular biology of this condition should provide further insights for its effective management.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
The practical value of preoperative intraocular lens power calculations in "normal" eyes with less than 4.50 diopters (D) of myopia or hyperopia was evaluated in a consecutive series of 520 eyes that underwent cataract extraction and lens implantation by four experienced surgeons at The Wilmer Ophthalmological Institute. The observed postoperative results with the lenses selected by the surgeons were compared with results calculated for the measurement-predicted emmetropic power lens and for a standard 20-D lens. The need for postoperative spectacle correction of residual refractive errors was comparable for all three choices of lens. Only two eyes (0.4%) would have developed greater than 4.00 D of refractive error with either the "implanted" or "predicted-emmetropic" lenses, as would 11 eyes (2.1%) with the "standard" 20-D lens. The surgeons' deviation from the calculated emmetropic lens did not reduce postoperative refractive error.
Studies were undertaken on seven adult female buffaloes (Bubalus bubalis) premedicated with triflupromazine hydrochloride (0.3 mg/kg) and chloral hydrate (30 mg/kg). Anaesthesia was induced with thiopentone sodium (10 mg/kg) and animals were kept under intermittent positive pressure ventilation. Measurements were made for 30 min in the lateral position, for 20 min in the supine position and subsequently for 40 min again in the lateral position. Regurgitation during anaesthesia was avoided by evacuation of the rumen by rumenotomy two days prior to the experiment. When animals were in the lateral position there were minimal changes in arterial pressure and heart rate but central venous pressure rose. These changes were related to intermittent positive pressure ventilation. In the supine position, increase in heart rate (28%) was associated with profound hypotension (56%) and decrease in central venous pressure (171%) in these animals. There was a fall in venous oxygen tension and a marked increase (91%) in oxygen extraction ratio. Restoration to the lateral position ameliorated all these changes rapidly. It was suggested that a 'low pressure-low flow' circulatory state exists in anaesthetised adult buffaloes in the supine position.
In a study involving 50 multiparous subjects with poor cervical scores (less than or equal to 3), induction of labour by conventional amniotomy and oxytocin was compared with preinduction cervical ripening using a single administration of prostaglandin E2 (850 micrograms) in a new vaginal film formulation. Indications for elective delivery, maternal characteristics and distribution of cervical scores in the two groups were similar. Significant changes in mean cervical score were achieved within 12 hours of film insertion. In this group, 11 subjects (45.8%) established labour within 12 hours and a further 8 (33.3%) did so before 24 hours so that only 5 cases required amniotomy and oxytocin. Instrumental delivery was less in this group and none of these subjects required Caesarean section for a failure of induction. No adverse maternal or fetal side effects were observed. Convenience, ease of administration and stability of this new prostaglandin formulation make it a useful alternative to conventional induction of labour in the multiparous patient with a poor cervical score.
Adult Ascaridia galli and Heterakis gallinae obtained from the fowl (Gallus gallus) were treated in vitro with 10(-2) to 10(-5) M parbendazole and piperazine adipate for 10-60 min at 38 degrees C. Both the compounds at 10(-2) M caused mortality of A. galli and H. gallinae after a maximum of 30 min exposure. The effect of the drugs on the homogenates of the treated worm was investigated. Parbendazole (10(-2) M) inhibited malate oxidation by 68% in A. galli and 62% in H. gallinae. Piperazine adipate (10(-2) M) inhibited malate oxidation by 78% in both parasites. In A. galli oxaloacetate reduction was inhibited by 41 and 26% by 10(-2) M parbendazole and piperazine adipate, respectively; with H. gallinae this inhibition was found to be 39 and 55%, respectively. Aldolase activity in both the parasites was also inhibited by 10(-2) M parbendazole and piperazine adipate. Both compounds caused an inhibition of acid phosphomonoesterase activity, but the activities of lactate dehydrogenase and alkaline phosphomonoesterase were not affected significantly. Parbendazole (10(-2) M) had no significant effect on the cholinesterase activity of these parasites, but piperazine adipate (10(-2) M) caused an inhibition of 96% in A. galli and 93% in H. gallinae. The possible mode of action of the drugs is discussed.
Since tubercular lesions form an important differential diagnosis in our country, tuberculoma models in mice have been created and imaged using iodine-125 radiolabelled antimycobacterial monoclonal antibodies for the aetiopathological diagnosis.
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An unusual presentation of disseminated mucormycosis as acute renal failure in a patient without any predisposing condition, is reported. The diagnosis was established at autopsy.
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Carbohydrate metabolism of Ascardia galli and Heterakis gallinae was studied after their exposure in vitro to 10(-2) to 10(-5) M piperazine adipate and parbendazole for 10 to 60 min. Following treatment with 10(-2) M piperazine adipate O2 uptake was reduced by 87% in A. galli and 70% in H. gallinae, while parbendazole (10(-2) M) reduced O2 uptake by 70% and 86%, respectively. Glycogen contents were reduced significantly by 10(-2) M piperazine adipate in both the worms, while lactic acid level was enhanced. Parbendazole, however, did not cause any significant change in glycogen contents and lactic acid level in either parasite.
A simple, sensitive and specific capillary GCMS assay method is described for the determination of a toxic metabolite of valproic acid, 2-n-propyl-4-pentenoic acid (4-ene-VPA), in rat plasma and urine. The method involves a single extraction of a small volume of plasma or urine with ethyl acetate. Extraction efficiency is virtually 100%. Derivatization with MTBSTFA reagent is extremely rapid. Calibration curves are linear in the concentration ranges of 0.5-45 micrograms/mL and 2-80 micrograms/mL in rat plasma and urine respectively. The lowest detection limit using 80 microL of plasma is 100 ng/mL. Following I.V. administration of 20 mg/kg of 4-ene-VPA, plasma levels can be monitored for 6 hours in rats. The results indicate that pharmacokinetics of 4-ene VPA are similar to those of the parent drug valproic acid (VPA) in the rat.