Biomedical subjects
Publications and source records attributed to S Ram.
Radiolabeled chlorpromazine was prepared by carboxylation of the N-trimethylsilyl derivative of norchlorpromazine with [11C]carbon dioxide, followed by in situ lithium aluminum hydride reduction. Radiochemical yields of 22-24% and radiochemical purities in the range of 93-98% were achieved.
A new synthesis is described for the production of the positron emitting radiopharmaceutical R-(+)-7-chloro-8-hydroxy-2,3,4,5-tetrahydro-3-N-[11C]methyl-1-phenyl-1H- 3-benzazepine (SCH 23390, 2a). This novel method involves reductive carboxylation, in which [11C]CO2 is reacted with the trimethylsilyl derivative of the desmethyl compound (SCH 24518, 1a) followed by treatment with lithium aluminum hydride, to afford no carrier added 11C-labeled SCH 23390. The procedure gave chemically and radiochemically pure 11C-labeled SCH 23390 in 53-72% radiochemical yield with an unoptimized specific activity of 40 Ci/mmol within 45-50 min from the end of bombardment.
Four cases of adult respiratory distress syndrome (ARDS) following aluminium phosphide ingestion (ALP) are being reported. The dose of the intoxicant varied from 2 tablets (6.0 gm) to 3 tablets (9.0 gm). All patients had shock at admission and developed ARDS within 6 hours. The exhalation of Phosphine, (PH3) detected by positive silver nitrate paper test, was the possible noxious triggering factor in our cases. The cases are being reported because of their rare occurrence.
The effect of aluminium phosphide (AlP) which is a systemic poison on the adrenal cortex was studied in 30 patients of AlP poisoning. A significant rise in the plasma cortisol level (greater than 1048 nmol/l) was observed in the twenty patients. Mortality was 50 per cent. Autopsy study could be undertaken only in 10 patients. Histopathology showed mild to moderate changes. In the rest (10 patients), the adrenal cortex was critically involved and the cortisol level failed to rise beyond normal levels (less than 690 nmol/l). The histopathology revealed severe changes (complete lipid depletion, haemorrhage, necrosis etc.) and all these patients died. In the critically ill patients, the cortisol levels remained low because of severe adreno-cortical involvement. The changes in the adrenal cortex could be due to shock or to cellular toxic effect of phosphine. The histopathological changes in various viscera showed congestion, edema and cellular infiltration. In the heart, there were patchy areas of necrosis, while the liver showed fatty changes and the lungs showed, in addition areas of gray/red hepatization. There was no adrenal apoplexy or extensive haemorrhage that could explain shock in these patients. Cardiogenic shock could not be confirmed due to lack of facilities for haemodynamic monitoring, but there was histopathological evidence in support of cardiovascular shock.
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Results of conventional agglutination and coagglutination (COA) tests for serotyping of enteropathogenic Escherichia coli (EPEC), Shigella, Salmonella and Vibrio cholerae were compared. Eighty isolates of different serotypes of EPEC falling in the Wellcome polyvalent (OK) 2, 3 and 4 antisera, showed good (4+) agglutination with COA reagent up to 1:960 dilution. Out of 50 strains of Shigella species tested, 25 of Sh. dysenteriae and 5 of Sh. sonnei gave good reaction up to 1:1920 dilution and 15 of Sh. flexneri up to 1:960 dilution in COA test. Similar reaction (4+) by 5 strains of Sh. boydii was seen up to 1:480 dilution only. All 100 isolates of different Salmonella species viz., S. paratyphi A (5), S. typhimurium (50), S. typhi (15), S. weltevreden (5) and S. senftenberg (25), when serotyped by COA, gave good reaction in 1:480 dilution except S. typhi factor 9 and dH antisera, which gave very weak reaction at 1:480 dilution and good reaction at 1:280 dilution. All seven isolates of V. cholerae gave good reaction in COA test even up to 1:1920 dilution. No cross reaction with any COA reagent was obtained in the 1206 heterologus isolates tested. Thus due to its higher efficiency, lower cost and good specificity, COA may prove to be a better method for serotyping of enteropathogens.
Mixed heart rate response has been observed in shock due to aluminium phosphide poisoning. Bradycardia observed in 9 of 30 cases studied indicated transient vagotonia and it reversed with atropine. Both tachycardiac bradycardiac responses were associated with significant increase in the mortality.
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In vitro sensitivity tests indicated econazole to be the best drug against all 30 isolates of Trichophyton species followed by miconazole, clotrimazole and tolnaftate. Econazole inhibited the growth of all isolates of Trichophyton species in low concentrations of 2-4 micrograms/ml except one isolate of T. rubrum which was inhibited by a concentration of 8 micrograms/ml. Miconazole was also able to inhibit growth of 73.3 per cent isolates of Trichophyton species in low concentrations of 2-4 micrograms/ml. On the other hand, only 13.3 per cent isolates were found sensitive at 2-4 micrograms/ml concentration to tolnaftate and clotrimazole. Relative resistance was encountered by 7 isolates (23.3%) to tolnaftate and 2 isolates (6.6%) to clotrimazole. Isolates of T. tonsurans were resistant to tolnaftate, whereas, the isolate of T. mentagrophytes was sensitive to all the drugs in low concentrations.
Silver nitrate impregnated paper test was performed with the gastric fluid and in breath in 50 patients of aluminium phosphide poisoning. The test was 100% positive with gastric fluid but was positive in 50% patients in breath. The test is simple, reliable and sensitive method to detect phosphine (PH3) for bed side diagnosis of aluminium phosphide (AIP) ingestion.
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Two litters of suckling pigs seronegative for transmissible gastroenteritis (TGE) virus were orally inoculated with live attenuated (P115) or virulent (M5C) strains of TGE virus. A third seronegative litter (controls) was given cell culture fluids from uninfected cells. Lymphocytes were collected from blood, spleen, mesenteric lymph nodes, and Peyer patches of euthanatized pigs at 0 day and approximately weekly until 26 days after exposure and at approximately 45 days after exposure. Sera were tested for virus-neutralizing antibody titers by use of plaque reduction. Lymphocytes were tested in a lymphocyte proliferation assay for uptake of [3H]thymidine after incubation with the homologous or the heterologous strain of inactivated TGE virus or uninfected cell culture fluids. Only pigs inoculated with virulent TGE virus developed clinical signs of TGE and shed virus. However, all pigs inoculated with TGE virus seroconverted at 6 days after exposure. Responses of lymphocytes from all sources from TGE virus-inoculated pigs peaked between 6 and 14 days after exposure. Pigs inoculated with virulent TGE virus had higher lymphocyte proliferative responses and neutralizing antibody titers than did pigs inoculated with attenuated TGE virus. Cessation of virus shedding coincided with the peak of lymphocyte proliferative responses. The highest responses were with intestinal lymphocytes (mesenteric lymph nodes and Peyer patches) from pigs inoculated with virulent TGE virus. The responses of intestinal lymphocytes from pigs inoculated with attenuated virus were not significantly different from those of pigs inoculated with cell culture fluid. Lymphocytes collected from all sources, except blood from M5C-inoculated pigs, had significantly (P less than 0.05) higher responses to the homologous than to the heterologous TGE virus stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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A new rapid high yield synthesis of radiolabeled N'-(4-11C-methyl)imipramine has been developed using a reductive-carboxylation approach, in which 11CO2 is reacted with either N'-trimethylsilyldesimipramine or N'-lithium derivative of desimipramine, followed by lithium aluminum hydride reduction, to give no carrier added or carrier added 11C-labeled imipramine respectively. The final product is characterized by chromatographic and spectroscopic methods.
Because renal function and electrolyte balance are commonly altered in premature infants, particularly those requiring ventilatory support, we studied the influence of assisted ventilation on renal electrolyte and water excretion in infants with birth weights less than 1501 g during the 2 days after birth. Twenty-two infants receiving assisted ventilation, either as intermittent mandatory ventilation or nasal continuous positive airway pressure, were compared with 21 spontaneously ventilating infants of similar birthweight and gestational age. Mean (and SEM) creatinine clearance was lower (p less than 0.05) in the assisted ventilation group on day 1 (2.9 +/- 0.4 versus 4.1 +/- 0.4 ml/min/1.73 m2) and on day 2 (4.1 +/- 1.0 versus 6.8 +/- 0.8 ml/min/1.73 m2, p = 0.05), and there was a correlation between creatinine clearance and mean blood pressure in both groups. Mean urine vasopressin was higher in the assisted ventilation group on the first day (360 +/- 86 versus 123 +/- 30 pg/mg creatinine; p less than 0.02) and correlated with higher urine osmolality. There were no differences in urine volume, in osmolar or free water clearances, or in the intake and urine excretion of sodium, potassium, and chloride. Plasma renin activity, urine aldosterone, and urine prostaglandin E2 were similar in both groups on both days. Neither the mode of assisted ventilation nor the cause of respiratory failure appeared to affect these results.
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