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Biomedical subjects

R Saxena

Publications and source records attributed to R Saxena.

At least 145 records · Page 8Linked to original sources
PubMed1997

Dose equivalents to neutron therapy facility staff due to induced activation.

The sources of the induced activity from the d(48.5)+Be fast neutron therapy beam of the Harper Hospital superconducting cyclotron have been investigated. The distribution of activity in the treatment room was measured, and the levels of dose equivalent to the staff were established. Activation spectra were measured with a high purity RE-Ge detector. Peaks corresponding to 28Al, 56Mn, 24Na, 64Cu, 66Cu, and 187W were present in the spectra. The dose equivalents due to the induced activation were measured by means of an ionization chamber type survey meter at six locations in the room. Irradiations of 120 monitor units were given at 15-min intervals, thus simulating the clinical situation. The measurements were made between the irradiations. The highest levels were registered around the treatment head. Two patterns are clearly distinguishable in these measurements. A fast decaying component with approximately 2 min half-life can be ascribed predominantly to 28Al and a slow growing component reaching saturation after about 4-5 treatments is associated with the presence of 56Mn. For uniform treatment load the activation build-up in each location was similar every day of the week with minimal values measured after the week end shut down. Personnel monitoring is achieved with dosimeters capable of detecting an extended range of neutron energies as well as beta rays and photons. Correlation between the number of fields treated and the doses to the radiation therapy technologists was shown. The mean dose equivalent received by the therapists is 7.1 +/- 0.2 microSv per treatment field. Means of reducing personnel dose equivalent levels are proposed.

Cyclotrons↗
PubMed1997

Post-cholecystectomy external biliary fistula.

BACKGROUND: External biliary fistula (EBF) following bile duct injury is a serious complication of cholecystectomy. METHODS: From January 1989 to December 1994, 37 patients with post-cholecystectomy external biliary fistula were seen at this centre. There were 14 partial, 22 complete and one sub-vesical duct of Luschka injury. Sixteen patients had a controlled EBF at presentation; 10 patients had intra-abdominal collections and seven patients presented with peritonitis. RESULTS: A staged approach to the management of these patients was adopted in which the initial management aimed at creating a 'controlled' fistula. This approach comprised conservative treatment (n = 9), percutaneous catheter drainage of intra-abdominal collections (n = 10), biliary drainage (n = 6), and surgical intervention (n = 7). One patient died because of progressive liver failure in spite of intensive management. Definitive management comprised the surgical repair of biliary strictures wherever indicated, after waiting for the acute problems to settle. CONCLUSIONS: By adopting a staged approach along with a judicious use of endoscopy, radiology and surgery that were based on clinical circumstances, it was possible to achieve satisfactory results for this otherwise distressing condition.

Adult↗
PubMed1997

Pregnancy in a patient of Glanzmann's thrombasthenia with antiplatelet antibodies.

Glanzmann's thrombasthenia is an autosomal recessive, inherited platelet function disorder. There is an absence of glycoprotein (GP) IIb/IIIa on the platelet membrane which causes reduced platelet aggregation with a defective platelet haemostatic plug formation. The management of bleeding episodes in these patients with platelet transfusions may result in alloimmunization and make the successive transfusions less effective. Pregnancy and delivery is rare in these patients and is associated with a high risk of severe haemorrhage. We describe a primigravida with Glanzmann's thrombasthenia and alloimmunization who developed secondary postpartum haemorrhage and was successfully treated with oral prednisolone.

Adult↗
PubMed1997

Lymphoid blast crisis during complete cytogenetic remission following interferon-alpha and hydroxyurea therapy.

Chronic myelogenous leukemia (CML) is a clonal disorder starting with a chronic phase and progressing to an acute blastic phase. Philadelphia (Ph) chromosome formation results in the relocation of the ABL oncogene from the chromosome 9q34 to BCR region on 22q11, forming the BCR/ABL fusion gene. The Ph chromosome once detected rarely disappears, except as a result of therapy. We present an unusual Ph-positive CML case, which developed lymphoid blast crisis in complete cytogenetic remission following interferon-alpha and hydroxyurea therapy. Sequential cytogenetic investigations were carried out on bone marrow. After a standard Ph translocation seen at diagnosis, from the 8th month of therapy all metaphases showed a normal diploid karyotype. Fluorescence in situ hybridization detected residual BCR/ABL-positive interphase cells during the 12th month of therapy. In the 14th month, the patient showed 27% blasts in marrow though normal cytogenetics was maintained. Present findings suggest blastic transformation occurred in a Ph-negative lymphoid clone. This supports the hypothesis that an actual leukemogenic event occurs in a multipotent stem cell prior to the acquisition of Ph translocation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Detection of beta-thalassaemia mutation insertion ATCT at codon 47/48 by ARMS technique for screening & prenatal diagnosis.

We report the diagnosis of the newly identified mutation codon 47/48 insertion ATCT using allele specific primers by the PCR-based amplification refractory mutation system (ARMS). Using this method prenatal diagnosis was provided to five couples at risk for this mutation. The assay provides an easy, non-isotopic method for identifying this mutation in cases which remain uncharacterized after screening for the 5 'common' and 12 'rare' Indian mutations. It will be useful for screening and prenatal diagnosis in at risk couples and help in the thalassaemia control programme in India.

Codon↗
PubMed1996

Linkage of a familial platelet disorder with a propensity to develop myeloid malignancies to human chromosome 21q22.1-22.2.

Linkage analysis was performed on a large pedigree with an autosomal dominant platelet disorder and a striking propensity in affected family members to develop hematologic malignancy, predominantly acute myelogenous leukemia. We report the linkage of the autosomal dominant platelet disorder to markers on chromosome 21q22. Four genetic markers completely cosegregate with the trait and yield maximum logarithm of difference scores ranging from 4.9 to 10.5 (theta = .001). Two flanking markers, D21S1265 and D21S167, define a critical region for the disease locus of 15.2 centimorgan. Further analysis of this locus may identify a gene product that affects platelet production and function and contributes to the molecular evolution of hematologic malignancy.

Acute Disease↗
PubMed1996

Donor arterial variations in liver transplantation: management and outcome of 527 consecutive grafts.

The impact of donor arterial variations and their management was investigated retrospectively in 527 consecutive allografts. Anomalous arteries were found in 161 grafts (30.6 per cent). There was no significant difference in the overall incidence of arterial complications between grafts with normal (3.6 per cent) and abnormal (5.6 per cent) anatomy. However, there was a higher incidence of arterial complications in transplants requiring multiple arterial anastomoses (P = 0.02), or anastomosis of donor vessels to recipient aorta with (P = 0.0003) or without (P = 0.04) an interposition graft for arterial reconstruction. The incidence of biliary complications was similar in grafts with a normal (18.8 per cent) or anomalous (18.0 per cent) arterial supply. Anomalies of hepatic arterial anatomy occur in one-third of all livers and do not compromise graft outcome unless multiple anastomoses or direct anastomosis to the recipient aorta are required for arterial reconstruction.

Aneurysm↗
PubMed1996

Intrahepatic segment III cholangiojejunostomy in advanced carcinoma of the gallbladder.

The majority of patients with advanced carcinoma of the gallbladder have irresectable disease and require palliation for jaundice, pruritus and cholangitis. Intrahepatic segment III cholangiojejunostomy has been described for palliation of high biliary obstruction in these patients. Forty-one patients with stage IV gallbladder cancer underwent intrahepatic segment III cholangiojejunostomy. Subsequent jaundice, pruritus and cholangitis were documented; liver function tests and isotope hepatobiliary scans were performed. All patients had jaundice, 29 had pruritus and 12 had cholangitis. Postoperative complications included anastomotic leak in six patients and wound infection in six. Five patients died within 30 days of operation. Thirty-two patients were available for follow-up. The procedure failed to relieve jaundice, pruritus or cholangitis in four patients; 18 were free of jaundice, pruritus and cholangitis until death or last follow-up, and ten had recurrent jaundice or cholangitis. Isotope scanning was found to be useful to predict success of the procedure. Intrahepatic segment III cholangiojejunostomy provided excellent palliation from jaundice, pruritus and cholangitis with acceptable mortality and morbidity rates in patients with advanced carcinoma of the gallbladder.

Adult↗
PubMed1996

Acquired biliary atresia.

Three infants are described in whom acquired biliary atresia developed during the perinatal period. In two cases this was related to a spontaneous perforation of the bile duct, and in the other it probably was related to previous surgery for duodenal and ileal atresias. Clinically, the symptoms in these patients differed from the congenital forms of biliary atresia; two of the infants had dilated intrahepatic ducts on ultrasonography, and all had restriction of disease to the extrahepatic bile ducts and an excellent response to surgery.

Bile Duct Diseases↗
PubMed1996

The DAZ gene cluster on the human Y chromosome arose from an autosomal gene that was transposed, repeatedly amplified and pruned.

It is widely believed that most or all Y-chromosomal genes were once shared with the X chromosome. The DAZ gene is a candidate for the human Y-chromosomal Azoospermia Factor (AZF). We report multiple copies of DAZ (> 99% identical in DNA sequence) clustered in the AZF region and a functional DAZ homologue (DAZH) on human chromosome 3. The entire gene family appears to be expressed in germ cells. Sequence analysis indicates that the Y-chromosomal DAZ cluster arose during primate evolution by (i) transposing the autosomal gene to the Y, (ii) amplifying and pruning exons within the transposed gene and (iii) amplifying the modified gene. These results challenge prevailing views of sex chromosome evolution, suggesting that acquisition of autosomal fertility genes is an important process in Y chromosome evolution.

Amino Acid Sequence↗
PubMed1996

Morbidity and mortality of laparoscopic cholecystectomy in an institutional setup.

Laparoscopic cholecystectomy (LC) though a very safe operative procedure does have its own morbidity and mortality. The present study was undertaken to analyze the morbidity and mortality of this procedure in an institutional setting. Between October 1992 and October 1995 a total of 433 patients received LC. Conversion to open cholecystectomy was required in 62 patients (14.3%). The decision to convert was made because the surgeon was forced to convert (3.7%) or the conversion was the operator's choice (10.6%). There was no difference in the conversion rate of consultants versus residents (14.4% vs. 14.2%). Major intraoperative and postoperative morbidity was encountered in 8.3% of patients. One patient required reexploration. The incidence of common bile duct (CBD) injury was 2.5%. There was no operative or 30 days mortality. However, two patients died in the follow-up period due to procedure-related complications. Low threshold for conversion, early recognition of morbidity, and prompt and judicious management of such complications under guided supervision is necessary in order to avoid major postoperative problems. The experience in a teaching hospital training program is different from that of an individual surgical setup.

Adolescent↗
PubMed1996

Endoscopic management of postoperative bile leak.

Significant bile leak is an uncommon but serious complication of biliary tract surgery. Of twenty-five patients presenting with postoperative bile leak, 11 had complete tie-off of common bile duct and required surgery, while the remaining 14 had injury without complete obstruction and could be managed by endoscopic methods. Of these 14 cases, bile leak occurred from the cystic duct in 11 patients and from the common hepatic duct, right hepatic duct and left hepatic duct in one patient each. Endoscopic procedures performed included sphincterotomy alone (four patients), sphincterotomy and stent placement (seven patients) and sphincterotomy followed by nasobiliary catheter drainage (three patients). There was no technical failure and bile leak was stopped in all patients. One patient died of haemobilia 5 days after stent placement. When technically feasible, postoperative bile leak can be managed safely and effectively by endoscopic methods, obviating the need for surgical reexploration.

Adult↗
PubMed1996

Genetic manipulations of microorganisms for the degradation of hexachlorocyclohexane.

Hexachlorocyclohexane (HCH) is an organochlorine insecticide which has been banned in technologically advanced countries. However, it is still in use in tropical countries for mosquito control and thus new areas continue to be contaminated. Anaerobic degradation of HCH isomers have been well documented but until recently there have been only a few reports on aerobic microbial degradation of HCH isomers. The isolation of these microbes made it possible to design experiments for the cloning of the catabolic genes responsible for degradation. We review the microbial degradation of HCH isomers coupled with the genetic manipulations of the catabolic genes. The first part discusses the persistence of residues in the environment and microbial degradation while the second part gives an account of the genetic manipulations of catabolic genes involved in the degradation.

Bacteria↗
PubMed1996

PDGF and IL-1 induce and activate specific protein kinase C isoforms in mesangial cells.

In vitro and in vivo data suggest a remarkable plasticity in the differentiated phenotype of intrinsic glomerular cells, which after injury express new structures and functions. We have shown that a protein kinase C (PKC) isoform, beta II, is expressed in diseased but not normal glomeruli. Since intrarenal cytokine synthesis has been implicated in the pathogenesis of progressive glomerular injury, we have hypothesized that these mediators induce a change in isoform profile. To test this hypothesis in vitro, we have determined whether platelet-derived growth factor (PDGF) and interleukin-1 (IL-1) alter the expression or activation of PKC isoforms in cultured mesangial cells (MCs). By immunoblot and ribonuclease (RNase) protection assays, both PDGF and IL-1 induce as early as 2 h de novo synthesis of PKC-beta II. Since MCs constitutively express PKC-alpha, -beta I, and -zeta, we also determined whether IL-1 or PDGF alter the activity of these isoforms. PDGF maximally induced translocation of PKC-alpha (10 min), -beta I (90 min), -epsilon (120 min), and -zeta (120 min) from the cytosolic to the membrane fraction. IL-1, in contrast, did not alter the distribution of alpha, beta I, or epsilon at any time measured but did induce PKC-zeta translocation. These data suggest inflammatory mediators regulate PKC isoform activity in diseased glomeruli both by de novo synthesis of unexpressed isoforms and by activation of constitutively expressed PKC isoforms.

Animals↗
PubMed1996

Prospective randomized trial comparing endoscopic sphincterotomy followed by surgery with surgery alone in good risk patients with choledocholithiasis.

BACKGROUND: Role of endoscopic sphincterotomy (ES) in high risk patients with choledocholithiasis is established but its role in good risk patients is unclear. DESIGN: A prospective randomized trial of endoscopic sphincterotomy followed by surgery (ES + S) versus surgery alone (SA) in good risk patients with choledocholithiasis. SETTING: A tertiary level referral hospital in north India; July 1991 to October 1993. PATIENTS AND METHODS: Thirty three out of 60 patients with choledocholithiasis were found suitable for randomization--16 were randomised to ES + S group and 17 to SA group. RESULTS: Common bile duct clearance was achieved in 11/13 (85%) patients in ES + S group and in 13/15 (87%) in SA group. Major complications occurred in 4/13 (31%) patients in ES + S group and 3/16 (19%) patients in SA group. These differences were not statistically significant, but patients in ES + S group were exposed to morbidity twice, procedure related morbidity of ES being 23%. No significant differences were observed in hospital stay and cost of treatment. CONCLUSIONS: Results of this trial do not support use of precholecystectomy ES in good risk patients with choledocholithiasis, since it did not offer any advantage over surgery alone.

Adult↗
PubMed1996

Pylephlebitis: a case report and review of outcome in the antibiotic era.

Pylephlebitis or septic thrombophlebitis of the portal vein, a precursor of hepatic abscesses, is an extremely rare and frequently fatal complication of diverticulitis. The following report describes a patient presenting with pylephlebitis and complicated diverticulitis. Diagnosis was confirmed by computed tomography. The patient had a favorable outcome with medical and surgical therapy, prompting us to evaluate historical treatment of pylephlebitis.

Acute Disease↗
PubMed1996

Choledochoduodenostomy: influence of risk factors in post-operative morbidity.

BACKGROUND: Choledochoduodenostomy is performed for a variety of lower common bile duct lesions. AIMS: To analyse the influence of risk factors on the post-operative morbidity following choledochoduodenostomy. METHODS: Relation of risk factors including age more than 60 years, medical Illness, hemoglobin less than 10 g/dL, albumin less than 3 g/dL, bilirubin more than 10m/dL, presence of cholangitis at admission (treated pre-operatively), use of pre-operative endoscopic sphincterotomy and common bile duct diameter at surgery were related to the occurrence of post-operative morbidity was studied using univariate analysis. RESULTS: Fifty patients underwent choledochoduodenostomy. One patient (2%) died; major post-operative morbidity occurred in 12 patients (24%). Presence of cholangitis at admission was the only factor related (p = 0.00012) to the occurrence of post-operative morbidity. No long-term complications were encountered in 35 patients (70%) mean with followup period of 28 (range 8-60) months. CONCLUSIONS: Choledochoduodenostomy is a safe permanent drainage procedure for benign lower biliary obstruction.

Age Factors↗