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Biomedical subjects

D R Singh

Publications and source records attributed to D R Singh.

33 records · Page 2Linked to original sources
PubMed1978

A possible combination of hypoxic cell sensitizer with an oxic protector: implications for radiotherapy.

This paper discusses the results of experiments using γ-rays and a hypoxic sensitizer metronidazole (MET) and also a well-known protector, mercaptoethylamine (MEA), individually and in combination, on the survival of the yeast S. cerevisiae BZ 34. MET (5mM) gave a hypoxic enhancement ratio (ER) of 1·3. MEA (5mM, 10mM) gave a dose-modifying factor (DMF) of 1·9 and 2·3 respectively for euoxic cells. However, the DMFs for hypoxic cells were 1·0 and 1·1 for 5 and 10mM concentrations of MEA. A combination of 5mM MEA and 5mM MET gave a DMF of 2·0 for euoxic cells and the ER remained at 1·3 for hypoxic cells. The "effective" oxygen enhancement ratios were 2·3 and 1·7 for the control and the sensitizer respectively. In the combination this value was equal to or even slightly less than 1. All DMF, ER and OER values were derived from D(0) values of the survival curves. The values based on 10% survival are almost equal to those derived from D(0) values. All the survival curves gave the same extrapolation number, showing that the chemicals individually or in combination were truly dose-modifying.These results indicate that protectors such as MEA could be preferentially protecting euoxic cells, and that combining such "oxic protectors" with a hypoxic sensitizer could result in protecting euoxic cells while the sensitization of hypoxic cells was not much reduced. The implications of our results for radiotherapy are discussed. It appears that the use of nontoxic oxic protectors may be a useful adjuvant in overcoming the hypoxic-cell problem in radiotherapy.

Dose-Response Relationship, Drug↗
PubMed1976

Effect of dimethyl sulfoxide (DMSO) on radiation-induced heteroallelic reversion in diploid yeast.

Dimethyl sulfoxide has cryoprotective and radioprotective properties. It is also an efficient scavenger of radicals produced by raiolysis of water. Gamma-induced reversions of diploid yeast in the presence of this chemical during irradiation have been studied. The dose-modifying factor was in the same range as for survival. When the yeast was irradiated in the frozen state the observed protection by DMSO disappeared. The results are discussed in terms of direct and indirect actions of radiations and the radical-scavenging ability of this chemical.

Alleles↗
PubMedDate not supplied

Stripping without a stripper.

Varicose veins afflict some 10 to 20% of the population in the west. It is believed to be less prevalent in the developing nations. Though there are absolute indications of surgery for varicose veins, people in Nepal come for treatment of the varicose veins either to join the army or to work abroad. Not all hospitals in Nepal are equipped with a vein stripper. In KMCTH, we studied 29 patients who had their long Saphenous veins stripped either with a stripper or by tunnelling around the Saphenous vein. We found that the long Saphenous vein could be stripped via the tunnelling method with an additional incision above the knee joint which is cosmetically accepted by our patients Moreover the patients were much satisfied because of minimal or no bruises in the post operative period as compared to those who had the long Saphenous vein stripped with a stripper.

Adolescent↗
PubMedDate not supplied

Intra abdominal abscess presenting as a thigh abscess.

Secondary thigh abscesses are rare, and their cause is often obscure. We report a case of an elderly diabetic who presented with thigh abscess secondary to tuberculous sacroilitis. Key words: Secondary thigh abscess, retroperitoneal abscess, tuberculous sacroilitis.

Abdominal Abscess↗
PubMedDate not supplied

Controversies in the management of acute pancreatits.

INTRODUCTION: Acute pancreatitis accounts for three to five percent of admission to hospital for abdomen pain. Though most are of mild form, the severer form takes a toll of some ten percent. AIMS AND OBJECTIVES: This study aims to make a retrospective analysis of some fifty four admissions for acute pancreatitis admitted to Kathmandu Medical College Teaching Hospital in the past twenty four months. It also aims to highlight some of the controversies that have come up as to its management. RESULTS: Among the 54 admissions for acute pancreatitis, there were thirty nine patients. Sixteen (41%) of them were female and twenty three (51%) male. Their ages ranged from twenty one to ninety years, with an average of forty one years. Surprisingly no patients were between sixty to eighty years bracket. Thirteen (33%) of the patients had gall stones in ultrasound. Two (5%) of the patients were suffering from mumps and Eleven (28%) no causal factors were found. While thirteen (33%) patients suffered from alcoholic pancreatitis. All of them were male. Of the alcoholic group, five (38%) had recurrent attacks. Five (38%) from the biliary and two (18%) from the idiopathic group had recurrent attacks. Four patients were operated on emergency basis. Three with the diagnosis of peritonitis and another eighty four year old lady with features of associated cholangitis were found to have acute pancreatitis at operation. One of them underwent peritoneal toileting; two had cholecystectomy and peritoneal toileting while the eighty four year old lady underwent cholecystectomy, common bile duct exploration and peritoneal toileting. All fared well post-operatively.

Acute Disease↗
PubMedDate not supplied

Omental torsion: a case report.

Omental torsion is a rare cause of acute abdomen. Most often it presents with sign and symptoms of acute appendicitis. It is seldom considered in the differential diagnosis preoperatively based on clinical findings and the diagnosis is only established during surgery. We present a case of omental torsion in a middle aged male patient who presented with findings suggestive of appendicular perforation and underwent emergency laparotomy.

Adult↗
PubMedDate not supplied

Saphenous--peritoneal shunt in refractory ascites: a neglected technique.

Management of intractable ascites has always been a challenge. Peritoneovenous shunt (PVS) plays a major role in the surgery of intractable ascites in patients with liver cirrhosis. Positive pressure gradient between the ascitic fluid and venous pressure leading to one-way drainage of ascitic fluid into venous circulation is the mainstay. Over decades, various modifications of shunting technique have been done. Here we report our experience with this procedure which is safe, easy and effective. Here the long saphenous vein is used as a drainage system. One-way ascites flow is ensured by a natural valve in the saphenous orifice.

Ascites↗