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T Patel

Publications and source records attributed to T Patel.

72 records · Page 4Linked to original sources
PubMed1992

The mapping by high-pH anion-exchange chromatography with pulsed amperometric detection and capillary electrophoresis of the carbohydrate moieties of human plasma alpha 1-acid glycoprotein.

The reducing oligosaccharides released from alpha 1-acid glycoprotein (AGP) by conventional hydrazinolysis have been analyzed by two different mapping techniques, using high-pH anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) and capillary electrophoresis (CE) with uv detection at 190 nm. The CE measurements proved about 4000 times more sensitive than the measurements by HPAE-PAD. The N-glycan pool was fractionated by Mono Q anion-exchange chromatography, and individual fractions so obtained were desialylated using Vibrio cholerae neuraminidase. The resulting asialo-N-glycans were further analyzed by HPAE-PAD, revealing 2 major, 4 intermediate, and 4 small peaks and at least 3 spikes, which counted for at least 13 different asialo-N-glycans. The carbohydrate structures were tentatively assigned by comparison of the Mono Q-separated N-glycans with the known AGP carbohydrate structures and known structures contained in a mapping database that allows structural assignment of N-glycans by mere comparison of retention times. In addition to the hitherto known AGP carbohydrate structures, we have tentatively identified a number of sulfated N-glycans that are currently being analyzed in more detail. We have also compared the glycan pools recovered from AGP using hydrazinolysis and glycopeptidase F (PNGase F). Approximately 40 distinct peaks could be detected in the hydrazinolysis-derived N-glycan pool by either technique (HPAE-PAD and CE), while about 30 distinct peaks were detected in the N-glycan pool derived by PNGase F digestion of the tryptic AGP digest of the same batch of AGP. These differences were attributed to an increased desialylation (approximately 3 mol%) during hydrazinolysis, based on the detection by HPAE-PAD and CE of free sialic acid and monosialylated oligosaccharides in the glycan pool derived by conventional hydrazinolysis. The integrity of the N-glycans' chitobiose core was examined by 500-MHz 1H NMR spectoscopy. The hydrazinolysis procedure could be optimized such that the hydrazinolysis-derived N-glycan pool was chromatographically essentially identical to the PNGase F-derived N-glycan pool. Hydrazinolysis proved best, with practically no loss of N-acetlylneuraminic acid and the closest resemblance to the PNGase F-derived N-glycan pool, using an automated apparatus. Notably, it was recognized that, in our hands, PNGase F digestion in the presence of sodium dodecyl sulfate resulted in partial desialylation of the liberated N-glycans.

Capillary Action↗
PubMed1992

Value of scintigraphic localization of obscure gastrointestinal bleeding.

A total of 51 technetium-99m (99mTc)-labelled autologous red cell (LRC) scans performed on 49 patients for the localization of obscure gastrointestinal bleeding over a 5-year period was reviewed. The sensitivity for LRC scanning was 72.7% with a positive predictive value of 84.2%. Forty patients underwent both LRC scanning and visceral angiography during the same admission; angiography had a sensitivity of 38.9% compared with 66.7% for LRC scanning and the positive predictive values were 77.8% and 85.7%, respectively. Overall, the site of bleeding was located in 22 (45%) of 49 patients, but LRC scanning alone was successful in identifying the lesion in 16 (33%) cases. In patients who continue to bleed to the point of requiring operation, a combination of scintigraphy and angiography will localize a source in 70% of patients.

Aged↗
PubMed1991

Drug-induced colonic pseudo-obstruction. Report of a case.

Colonic pseudo-obstruction may have many possible causes. Some of these are well described and pose no diagnostic problems. Drug-related colonic pseudo-obstruction remains underreported, but is of importance in modern society where drugs are endemically abused. This case highlights the importance of drugs in altering colonic motility and emphasizes the nonsurgical management of this condition.

Adult↗
PubMed1991

T-U wave alternans. A case report and review of the literature.

A patient with severe hypertension, hypokalemia and marked T-U wave alternans on electrocardiogram is reported for its rarity. Relevant literature is reviewed. Recent data indicate that electric alternans is related to changes in action potential configuration, and that it may be a marker of cardiac electrical instability.

Arrhythmias, Cardiac↗
PubMed1991

Metastatic angiosarcoma of the ovary.

A case of metastatic angiosarcoma of the ovary, complicated by disseminated intravascular coagulation, is described. The tumour was diagnosed by histopathologic examination and immunohistochemical studies. Angiosarcoma of the ovary, although extremely rare, appears to be a highly malignant neoplasm with an aggressive course and effective therapy is unknown.

Adult↗
PubMed1990

The management of postoperative chylous ascites. A case report and literature review.

Chylous ascites remains rare as a complication of surgical intervention. Although therapeutic manoeuvres to control chylous ascites have been developed over the past 20 years, its pathophysiology is poorly understood. Conservative approaches involving dietary restriction of long-chain triglycerides and salt, together with multiple paracenteses, are still the therapies of choice. Persistent chylous ascites may be treated surgically by ligation of leaking lymphatics or implantation of a peritoneovenous shunt once the lymphatic anatomy has been defined by preoperative investigations. We report a case of chylous ascites developing after laparotomy and duodenotomy for obscure gastrointestinal bleeding, which did not respond adequately to medical therapy and was successfully managed by the insertion of a peritoneovenous shunt.

Aged↗
PubMed1986

Cloning of cDNA coding for human tissue-type plasminogen activator and its expression in Escherichia coli.

cDNA clones of the mRNA coding for tissue-type plasminogen activator (t-PA) have been obtained and their nucleotide sequences compared to those reported previously. A gene coding for t-PA has been reconstructed and inserted into vectors for expression in prokaryotic cells. Relatively high levels of t-PA accumulated in inclusion bodies in Escherichia coli containing an optimized expression plasmid, but only a small proportion of the insoluble protein was recovered as active enzyme using a variety of solubilization procedures.

Amino Acid Sequence↗
PubMed1983

Lectin-like polypeptides of P. falciparum bind to red cell sialoglycoproteins.

Attempts to control human malaria by immunological means could be compromised by antigenic variability within and between different strains of malarial parasites1. A useful alternative approach might be to block parasite antigens which are important in the mechanisms of invasion of red cells. As the major human parasite Plasmodium falciparum is highly specific for human red cells, isolation of the proteins involved in the recognition of red cells by this parasite might be of particular value. Recent studies suggest that the major red cell sialoglycoproteins (SGPs), glycophorins A, B and possibly C, may carry the sites recognized by the parasite2-4. Furthermore, because certain carbohydrates present on SGPs such as N-acetylglucosamine are able to block invasion by the parasite5, they may be involved in the initial interaction between parasite and red cell. We have now identified parasite proteins which bind to SGP or N-acetylglucosamine on Sepharose 4B columns. Three proteins, of molecular weights (MWs) 140,000 (140K), 70K and 35K, seem to be specifically bound by N-acetylglucosamine.

Acetylglucosamine↗
PubMed1983

Efficient synthesis of enzymatically active calf chymosin in Saccharomyces cerevisiae.

We have constructed a high-efficiency expression vector to direct the synthesis of heterologous polypeptides in yeast. The vector is termed a sandwich expression vector as the heterologous gene is inserted between the 5' and 3' control regions of the efficiently expressed yeast PGK gene. We have used this vector to direct the expression of three derivatives of the calf chymosin cDNA gene; preprochymosin, prochymosin and chymosin. Prochymosin is synthesised to at least 5% of total yeast-cell protein and furthermore, it can be readily activated to produce an enzyme which has milk-clotting activity.

Animals↗
PubMed1982

Chemical synthesis and cloning of a gene for human beta-urogastrone.

A DNA duplex coding for the 53 amino acids of human beta-urogastrone has been synthesised. Computer assisted design of the gene included restriction endonuclease sites for plasmid insertion, a termination codon and two triplets coding for lysine at the 5'-end of the structural gene. The synthesis involved preparation of 23 oligodeoxyribonucleotides by phosphotriester procedures coupled to rapid HPLC techniques. The gene was constructed in two halves by enzymatic ligation of the oligonucleotides and cloned into a specially constructed chimeric plasmid vector. Escherichia coli K12 MRC8 was transformed by the plasmid and clones containing the full gene sequence were isolated and characterised.

Amino Acid Sequence↗
PubMed1980

The expression in E. coli of synthetic repeating polymeric genes coding for poly(L-aspartyl-L-phenylalanine).

Two dodecadeoxynucleotides of defined sequence have been synthesised by phosphotriester methodology. They can be polymerised to give a double stranded DNA which codes, when read in the correct phase, for the repeating dipeptide poly(aspartyl-phenylalanine). This polymeric DNA has been cloned in E. coli K12 using as vector a plasmid having a controllable bacterial promoter upstream of the insertion site. Clones containing genes coding for up to 150 repeats of (aspartyl-phenylalanine) have been isolated and characterised. The polymeric inserts appear to be stable over many generations and are expressed in E. coli under the control of the bacterial promoter, to give a polymer of phenylalanine and aspartic acid which may be broken down enzymically to yield aspartyl-phenylalanine.

Amino Acid Sequence↗
PubMedDate not supplied

Juvenile colonic polyposis with villous adenoma and retroperitoneal fibrosis: Report of a case.

A 25-year-old Nigerian black woman was found to have polyps involving the rectum, rectosigmoid, and sigmoid colon on air-contrast barium-enema examination. Resection of a segment of sigmoid colon revealed numerous polyps that were predominantly of the juvenile type, in keeping with the diagnosis of juvenile polyposis of the colon. This case is unusual because of the coexistence of retroperitoneal fibrosis with juvenile polyposis of the colon. In addition, one of the colonic polyps was a villous adenoma. The implications these findings are discussed in relation to polyposis syndromes reported previously.

Adenoma↗