PubMed Health⌕ Search

Biomedical subjects

Jaswinder Singh

Publications and source records attributed to Jaswinder Singh.

At least 19 recordsLinked to original sources
PubMed2006

High-frequency Ds remobilization over multiple generations in barley facilitates gene tagging in large genome cereals.

Transposable elements have certain advantages over other approaches for identifying and determining gene function in large genome cereals. Different strategies have been used to exploit the maize Activator/dissociation (Ac/Ds) transposon system for functional genomics in heterologous species. Either large numbers of independent Ds insertion lines or transposants (TNPs) are generated and screened phenotypically, or smaller numbers of TNPs are produced, Ds locations mapped and remobilized for localized gene targeting. It is imperative to characterize key features of the system in order to utilize the latter strategy, which is more feasible in large genome cereals like barley and wheat. In barley, we generated greater than 100 single-copy Ds TNPs and determined remobilization frequencies of primary, secondary, and tertiary TNPs with intact terminal inverted repeats (TIRs); frequencies ranged from 11.8 to 17.1%. In 16% of TNPs that had damaged TIRs no transposition was detected among progeny of crosses using those TNPs as parental lines. In half of the greater than 100 TNP lines, the nature of flanking sequences and status of the 11 bp TIRs and 8-bp direct repeats were determined. BLAST searches using a gene prediction program revealed that 86% of TNP flanking sequences matched either known or putative genes, indicating preferential Ds insertion into genic regions, critical in large genome species. Observed remobilization frequencies of primary, secondary, tertiary, and quaternary TNPs, coupled with the tendency for localized Ds transposition, validates a saturation mutagenesis approach using Ds to tag and characterize genes linked to Ds in large genome cereals like barley and wheat.

Base Sequence↗
PubMed2006

Management of superior vena cava syndrome by internal jugular to femoral vein bypass.

We report a 30-year-old man with superior vena cava syndrome due to fibrosis from a previously irradiated malignant thymoma. The patient presented 4 years after the initial treatment, after having been lost to follow-up. Investigations revealed total obstruction of the superior vena cava, and right subclavian and right internal jugular vein. The patient underwent an extra-anatomic bypass (ringed polytetrafluoroethylene graft 10-mm diameter) between the left internal jugular vein and the left femoral vein brought in a subcutaneous tunnel over the anterior chest and abdominal wall. Entry to the thoracic cavity was avoided due to extensive fibrotic changes visualized in the computed tomographic chest scan. Follow-up Doppler at 2 months, 6 months, 1 year, and 3 years showed a patent graft. An internal jugular vein to the femoral vein bypass is a simple method for palliation of superior vena cava syndrome.

Adult↗
PubMed2005

Endoscopic ligation vs. sclerotherapy in adults with extrahepatic portal venous obstruction: a prospective randomized study.

BACKGROUND: Endoscopic sclerotherapy is a well-established treatment for bleeding esophageal varices, although it has a substantial complication rate. A prospective randomized trial was conducted to determine whether endoscopic variceal ligation is safer and more effective than sclerotherapy in adults with bleeding esophageal varices because of extrahepatic portal venous obstruction. METHODS: Thirty-six patients underwent sclerotherapy and 37 had band ligation. RESULTS: Ligation and sclerotherapy were equally effective for achieving variceal eradication (94.6% vs. 91.7%, respectively; p=0.67). However, ligation achieved eradication with fewer endoscopic sessions (3.7 [1.2] vs. 7.7 [3.3]; p <0.0001) and within a shorter time interval (50.1 [17.7] days vs. 99 [54.8] days; p <0.0001). In the ligation group, recurrent bleeding was less frequent (2.7% vs. 19.4%; p=0.028; however, Bonferroni correction for multiple testing removes this significance) and the rate of major complications was lower (2.7% vs. 22.2%; p=0.014). Total cost per patient was significantly higher in the sclerotherapy vs. the ligation group ($216.6 [71.8] vs. $182.6 [63.4]; p=0.035). During the follow-up period after variceal eradication, no significant differences were found between the sclerotherapy and the ligation groups with respect to recurrent bleeding (3% vs. 2.9%; p=1.0), esophageal variceal recurrence (9.1% vs. 11.4%; p=1.0), and formation of new gastric varices (9.1% vs. 14.3%; p=0.51). CONCLUSIONS: Variceal band ligation is superior to sclerotherapy, because it is less costly and achieves variceal eradication more quickly, with lower relative frequencies of recurrent variceal bleeding and complications.

Adolescent↗
PubMed2005

Evolutionary expansion, gene structure, and expression of the rice wall-associated kinase gene family.

The wall-associated kinase (WAK) gene family, one of the receptor-like kinase (RLK) gene families in plants, plays important roles in cell expansion, pathogen resistance, and heavy-metal stress tolerance in Arabidopsis (Arabidopsis thaliana). Through a reiterative database search and manual reannotation, we identified 125 OsWAK gene family members from rice (Oryza sativa) japonica cv Nipponbare; 37 (approximately 30%) OsWAKs were corrected/reannotated from earlier automated annotations. Of the 125 OsWAKs, 67 are receptor-like kinases, 28 receptor-like cytoplasmic kinases, 13 receptor-like proteins, 12 short genes, and five pseudogenes. The two-intron gene structure of the Arabidopsis WAK/WAK-Likes is generally conserved in OsWAKs; however, extra/missed introns were observed in some OsWAKs either in extracellular regions or in protein kinase domains. In addition to the 38 OsWAKs with full-length cDNA sequences and the 11 with rice expressed sequence tag sequences, gene expression analyses, using tiling-microarray analysis of the 20 OsWAKs on chromosome 10 and reverse transcription-PCR analysis for five OsWAKs, indicate that the majority of identified OsWAKs are likely expressed in rice. Phylogenetic analyses of OsWAKs, Arabidopsis WAK/WAK-Likes, and barley (Hordeum vulgare) HvWAKs show that the OsWAK gene family expanded in the rice genome due to lineage-specific expansion of the family in monocots. Localized gene duplications appear to be the primary genetic event in OsWAK gene family expansion and the 125 OsWAKs, present on all 12 chromosomes, are mostly clustered.

Arabidopsis↗
PubMed2004

Endoscopic management of early postoperative biliary ascariasis in patients with biliary tract surgery.

Bile leak and residual stones are well known complications of biliary tract surgery. In endemic areas of ascariasis, invasion of the biliary tract by roundworms during the early postoperative period is an infrequent but serious complication. The present study describes the endoscopic management of postoperative biliary ascariasis in 19 consecutive patients. There were 5 men and 14 women with a mean age of 33.3 +/- 6.3 years. All patients had undergone cholecystectomy, with choledocholithotomy and placement of a T-tube in 13 (68.4%) patients. Eight (42.1%) patients including two with T-tubes were acutely sick at referral. Altogether, 16 (84.2%) patients had widened papillae due to previous endoscopic sphincterotomy (3 patients) or recent dilatation of the sphincter of Oddi by Bake's dilators (13 patients). All patients with a T-tube in situ had undergone unsuccessful attempts to remove the worms by flushing saline through the T-tube. Endoscopic retrograde cholangiopancreatography was performed 4 to 16 days after biliary tract surgery and revealed roundworms in the common bile duct in 10 patients, in the hepatic ducts in 2, or in both ducts in 7. Three patients had coexisting biliary leakage: from the cystic duct stump in two and from a T-tube track in one. Endoscopic treatment consisted of extracting the worms from the biliary tree and placing stents in those with coexisting leakage. Endoscopic success was defined as complete worm extraction and resolution of biliary leakage and was achieved in all patients. Complications occurred in one (5.3%) patient. We concluded that endoscopic management is an effective, safe approach for extracting ascarids from the biliary tree during the early postoperative period. It reduces the hospital stay, avoids T-tube-related complications, and permits a postoperative complication to be treated using a nonsurgical method.

Adult↗
PubMed2004

Fifteen-year follow up of endoscopic injection sclerotherapy in children with extrahepatic portal venous obstruction.

BACKGROUND AND AIM: Endoscopic sclerotherapy has emerged as an effective treatment for bleeding esophageal varices both in adults and children but the long-term outcome is poorly defined in children. The authors report a 15-year follow up of sclerotherapy in children with extrahepatic portal venous obstruction. METHODS: Between June 1982 and February 1992, 69 children with bleeding esophageal varices underwent sclerotherapy; variceal eradication was achieved in 63 (91.3%) patients, with procedure-related morbidity of 28.9% and mortality of 1.4%. Fifty-nine patients with variceal eradication were followed for between 10.4 and 20.1 years (mean, 15.1 +/- 3.1 years). RESULTS: After a median period of 3 years (range, 1.2-12.8 years), seven (11.9%) patients presented with recurrent bleeding (esophageal varices, four; gastric varices, two; and duodenal ulcer, one). Recurrent bleeding occurred in six of seven (85.7%) patients within the first 4 years of initial variceal eradication. Esophageal varices recurred in eight (13.6%) patients. Five of the seven patients with recurrent bleeding and all eight with recurrent varices were effectively treated with further sclerotherapy. Two patients with gastric variceal bleeding unresponsive to sclerotherapy underwent shunt surgery. Elective surgery was required in eight additional patients for reasons other than recurrent varices or bleeding. CONCLUSIONS: The authors conclude that (i) sclerotherapy is the ideal, safe and effective treatment for bleeding esophageal varices, that it prevented bleeding in 88.1% patients after variceal eradication and hence, should be included in primary management strategies; (ii) follow-up endoscopy should be performed on a yearly basis for the first 4 years after variceal eradication; and (iii) surgery is required as a complementary technique for patients with uncontrolled bleeding, painful splenomegaly, growth retardation and symptomatic portal biliopathy.

Adolescent↗
PubMed2003

Endoscopic sphincterotomy in the management of bile duct stones in children.

OBJECTIVE: Endoscopic sphincterotomy (ES) is a widely accepted method of extracting bile duct stones (BDS) in young as well as in elderly patients. The present study was undertaken to assess the safety and efficacy of ES for the treatment of BDS in children, seven of whom were critically sick because of suppurative cholangitis or pancreatitis. METHOD: Over a period of 33 months, ES was performed in 16 consecutive children aged 7-16 yr with BDS. Nine patients had gallbladder in situ, and seven had previously undergone cholecystectomy. The coexisting abnormalities were gallstones and hepatic duct stones in one patient each and dead fragmented roundworms in 11 patients. Seven (five with an intact gallbladder and two cholecystectomized) patients presented with severe complications of BDS such as severe cholangitis in six and acute severe pancreatitis in one. RESULTS: ES was technically successful in all patients, and complete stone extraction was achieved in 15 (93.8%) patients. Complications were minor bleeding in one (6.3%) patient without mortality. One patient with coexisting gallstones underwent cholecystectomy at a later date. During a mean follow-up period of 4-32 months, one patient developed recurrent biliary symptoms because of biliary ascariasis. CONCLUSIONS: We conclude ES is a safe and an effective method of treating BDS in children with previous cholecystectomy, and in those presenting with severe complications of BDS, such as pyogenic cholangitis or acute pancreatitis regardless of the presence of gallbladder.

Adolescent↗