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Biomedical subjects

M Singh

Publications and source records attributed to M Singh.

At least 901 records · Page 50Linked to original sources
PubMed1988

Survival of rabbit platelets labeled with gallium 67.

The viability of rabbit platelets labeled with radioactive gallium was determined to analyze the feasibility of using platelets labeled with gallium 68 as an imaging reagent for positron emission tomography. Platelets were labeled with a complex of the longer lived gallium 67 and mercaptopyridine-N-oxide (MPO) or with sodium chromate Cr 51. Their survival after transfusion was measured. Labelling efficiency of 67Ga-MPO was 6.5% to 45.8% (26.8% +/- 2.8%) when platelets were suspended in saline solution, but was much lower (1.6% +/- 0.8%) in plasma. Platelets labeled with either radioisotope in a saline medium survived as well as platelets labeled with 51Cr in plasma. Recovery values 1 hour after transfusion and mean platelet survivals were 68.6% +/- 4.9% and 3.4 +/- 0.2 days for 67Ga in saline solution, 76.5% +/- 6.8% and 3.8 +/- 0.5 days for 51Cr in saline solution, and 73.7% +/- 7.4% and 3.6 +/- 0.5 days for 51Cr in plasma. Labeled platelet concentrates always contained extra radioactivity not firmly bound to viable platelets. A postlabeling wash in saline solution did not reduce this contamination and resulted in reduction of the number of viable platelets. The results showed that rabbit platelets labeled with 67Ga-MPO survived in the circulation as well as those labeled by a standard protocol with sodium chromate Cr 51.

Animals↗
PubMed1987

Radiation-induced leiomyosarcoma of the great vessels presenting as superior vena cava syndrome.

A patient with a pleomorphic intravascular leiomyosarcoma of the great vessels of the neck and mediastinum presented clinically with a superior vena cava syndrome. A latent period of 29 years elapsed between receiving orthovoltage radiation to the neck and right side of chest to treat recurrent ganglioneuroblastoma, and the appearance of a leiomyosarcoma and subsequent recurrences. The patient underwent partial resection of the tumor, received adjunct chemotherapy, and was shown to be free of disease by clinical tests and by magnetic resonance imaging (MRI) 17 months after completion of chemotherapy. The criteria for the diagnosis of radiation-induced sarcomas are reviewed in relation to the present case. The critical role of magnetic resonance imaging in both the diagnosis and continued follow-up of the patient is described. This would appear to be the first reported case of radiation-induced intravascular leiomyosarcoma of the great vessels of the neck and mediastinum presenting as a superior vena cava syndrome.

Adult↗
PubMed1987

Effect of single amino acid changes in the region of the adenylylation site of T4 RNA ligase.

Preparation and analysis of a series of mutants of bacteriophage T4 RNA ligase that carry single amino acid changes at or near the site of covalent reaction with ATP (adenylylation) are described. The mutant proteins were constructed by site-directed mutagenesis of the gene for T4 RNA ligase (g63) cloned in M13 vectors, transfer of the mutant genes into a lambda pL-containing expression plasmid, and subsequent expression in Escherichia coli. The results give further evidence that Lys-99 is the adenylylation site and that the residue is also important to step 3 in the RNA ligase mechanism (ligation between acceptor and adenylylated donor). Mutations at Glu-100 or Asp-101 have no effect on adenylylation, but Asp-101 is shown to be crucial to both step 2 (transfer of adenylyl to donor) and step 3.

Adenosine Triphosphate↗
PubMed1987

Argon laser trabeculoplasty in Asian eyes.

Twenty two Asian eyes suffering from open angle glaucoma were treated by argon laser trabeculoplasty and were followed for an average of eleven months. 77.27% of eyes were controlled with ALT alone. The pressure lowering effect of argon laser trabeculoplasty in this series was found to be consistent. Argon laser trabeculoplasty may become the preferred method of treating open angle glaucoma in the Asian population.

Adolescent↗
PubMed1987

Effect of chronic feeding of ethanol diet of "average" fat content on rat pancreas.

The present study was done to determine the influence of dietary fat on the effect of ethanol on pancreatic macromolecular content and secretion. Weight-matched groups of Sprague-Dawley rats were divided into controls fed Rodent-Blox ad libitum; American Institute of Nutrition-76 (AIN-76) diet containing 12% calories as fat with 36% of carbohydrate calories replaced with 5% (weight/volume) concentration of ethanol fed ad libitum pair fed with animals given isocaloric amounts of AIN-76 diet for three to six months. Compared with Rodent-Blox fed controls, tissue content of trypsinogen, chymotrypsinogen, amylase, and lipase; specific activity and concentration of trypsinogen, chymotrypsinogen; and concentration of amylase were decreased at six months in AIN-76 fed controls. These changes did not result from diminished food intake, but were due to adaptation to the liquid diet. Animals fed AIN-76 diet plus ethanol did not show significant difference in the total content, specific activity, concentration, and secretion of digestive enzymes compared with those animals pair fed isocaloric amounts of AIN-76 diet. Activation of trypsinogen by exogenous trypsin was lower in rats fed AIN-76 diet and a similar change was observed in animals fed AIN-76 diet with ethanol for six months. These findings are in contrast to increased secretion of proteases and decreased trypsin inhibitor observed previously in animals fed ethanol in a diet containing "high" fat. These data indicate that ethanol effect on the pancreas is modified by dietary intake of fat and/or carbohydrates.

Amylases↗
PubMed1987

Effect of neurotensin on amylase secretion from rat pancreas in vivo and in vitro.

The effects of neurotensin, a tridecapeptide localized mainly in the gut, on pancreatic secretion are controversial. It is not clear whether the effects are mediated by direct or indirect effects. The present study was done to determine the effect of threshold doses of neurotensin in vivo in the rat as well as in vitro to clarify whether the action is direct or indirect. For in vivo studies the pancreatic duct of rats was cannulated and threshold doses of neurotensin and CCK-8 alone or in combination were infused as an intravenous bolus and pancreatic juice collected at 10-min intervals for 1 hr. For in vitro studies dissociated lobules and acini were incubated for 1 hr with 10(-11) -10(-6) M neurotensin with or without 10(-9) M CCK-8 (maximally effective dose). Amylase secretion in the pancreatic juice or in the medium was determined. Neurotensin and CCK-8 at a dose of 50 pM/kg increased pancreatic protein secretion in vivo. Neurotensin in combination with CCK-8 did not potentiate protein secretion. In the pancreatic lobules and acini, neurotensin 10(-11) -10(-6) M alone or in combination with CCK-8 (10(-9) M) did not stimulate amylase secretion above the basal level or that stimulated with CCK-8. The combined data indicate that the effect of neurotensin is not mediated by a direct action on the pancreatic acinar cells.

Amylases↗
PubMed1987

Spectrophotometric determination of sulphur dioxide.

Sulphur dioxide, an important industrial gas and air pollutant, is usually estimated using mercury salts. The authors have developed a method in which hazardous mercury salts are avoided. Sulphur dioxide is trapped in aqueous morpholine and mixed with the excess of dichromate solution in acidic medium. The hexavalent chromium in dichromate is reduced to trivalent chromium by sulphur dioxide and the excess of hexavalent chromium is determined with diphenylcarbazide which yields a soluble red-violet complex with an absorption maximum at 540 nm. The decrease in the absorbance values of the red-violet complex formed after reduction, when compared to that of a reagent control, is proportional to the concentration of sulphur dioxide used for reduction. Beer's law operates between 0.4 and 4 microg ml(-1) concentration of sulphur dioxide in solution.

Journal Article↗
PubMed1987

Infections of forest rat filaria, Breinlia booliati, in neonate and juvenile laboratory white rats.

The kinetics of Breinlia booliati infection in 3 inbred rat strains (Lewis, Wistar and Sprague Dawley) were investigated. One group of rats was infected as neonates (less than 24 hours of age) with third-stage larvae of B. booliati and the other group was infected as juveniles (4 weeks of age). The results showed that infection in the neonates were significantly different from the infection in the juveniles. The 60 rats infected as neonates, when necropsied between 8 to 10 months postinfection, yielded adult worms. The 2 neonatal infection groups of Lewis and Wistar strains showed highest susceptibility to the infections. The mean prepatent period was 85 days. Ninety to 95% of the infected rats were patent with microfilaraemia and a large percentage (33 to 47%) of them had high microfilaraemia counts exceeding 3000 mff/20 mm3 of blood and larger sizes (mean 157.11 mm for female adult worms and 61.88 mm for male adult worms. The adult worms were distributed equally in both the pleural (57%) and peritoneal cavity (43%). In most aspects, the neonatal infection group of the Sprague-Dawley strain was intermediate in susceptibility between the 2 neonatal infection groups of the Lewis and Wistar strains and the 3 juvenile infection groups. In contrast to neonatal infection groups, the 3 juvenile infection groups exhibited low infection rates (37%, 58% and 47% for the Lewis, Wistar and Sprague Dawley strains respectively), longer prepatent periods (mean 101 days), lower recovery rates (2 to 4%), lower adult worm loads (mean 0.4 to 0.8 female worms, and 0.2 to 0.8 male worms per rat), and smaller sizes (mean 141.24 mm for female adult worms and 53.75 mm for male adult worms). Forty-four to 57% of these infected rats harboured either single male or single female adult worms in the body cavity. Most (92%) of the adult worms recovered from the juvenile infection groups resided in the pleural cavity and the remaining 8% were recovered from the peritoneal cavity. Microfilaraemia could be detected in only 3/20 Lewis rats, 5/20 Wistar rats and 5/20 Sprague Dawley rats. The mean peak microfilaraemia of the 3 pooled juvenile infection groups was 632 mff/20 mm3 of blood, ranging from 7 mff/20 mm3 to 1856 mmf/20 mm3. Our results indicate that the susceptibility to B. booliati infection in white rats is both genetic and age-associated. The responses of the 2 distinct infection groups to B. booliati infections are discussed.

Animals↗
PubMed1987

Diarrhea in the intensive care unit: the role of hypoalbuminemia and the response to a chemically defined diet (case reports and review of the literature).

We describe five patients who developed acute kwashiorkor-like hypoalbuminemia during their hospitalization in the intensive care unit. With the initiation of enteral alimentation, diarrhea ensued and continued for at least 48 hours. Routine evaluation for the cause of diarrhea including stool culture for enteric pathogens, white blood cells, ova and parasites, Clostridium difficile cytotoxin, and flexible sigmoidoscopy was negative. When a peptide based formula (Vital HN, Ross Laboratories, Columbus, OH) was initiated, there was a significant reduction in stool output within 24 hours. In three of the five cases, hypoalbuminemia corrected within 2 weeks. Four of the five patients were discharged from the hospital. Although several reports have acknowledged the association between hypoalbuminemia and impaired gastrointestinal absorption, no previous enteral formula has been tolerated in these acutely ill patients until serum albumin levels had improved. Further studies will be required to confirm the better gastrointestinal tolerance of this peptide based formula in patients with severe hypoalbuminemia.

Adult↗