Biomedical subjects

N Rajan

Publications and source records attributed to N Rajan.

At least 37 records · Page 2Linked to original sources

PubMed1996

Stomach as a conduit for esophagus--a study of 105 cases.

BACKGROUND: The stomach is a well known esophageal substitute. To analyze the mortality and morbidity following total laryngopharyngoesophagectomy (TLPE) with pharyngogastric anastamosis done as a single-stage procedure. METHOD: The technique employed was esophageal extraction by stripping method followed by gastric pull up. In 104 patients transposition of the stomach was done through posterior mediastinum and in one patient through presternal route. RESULTS: Significant post-operative complications included pharyngocutaneous fistula in 15 patients (14.3%) and pneumonitis in 20 patients (19%). Fifteen patients (14.3%) died due to the causes related to surgery. All patients who survived were able to swallow solid and liquid food, on an average of 14 days post-operatively. CONCLUSION: The stomach as a conduit following TLPE is procedure which givens satisfying results when done in carefully selected patients.

Adult↗

PubMed1995

Characterization of recombinant human interleukin 4 receptor from CHO cells: role of N-linked oligosaccharides.

Interleukin 4 (IL-4) mediates its biological activities through interaction with its receptor on the cell surface. A recombinant extracellular domain of the alpha subunit of human interleukin 4 receptor was expressed in CHO cells and purified to homogeneity by a combination of ion exchange and immunoaffinity chromatography. Analysis of the purified protein by MALDI MS provided an average mass of 38,241 Da while microsequencing identified the site of the signal sequence processing to be Ser23-Gly24. The receptor was highly glycosylated, containing N-linked complex oligosaccharides with bi-, tri-, and tetraantennary structures. Five of the six potential glycosylation sites could be assigned to Asn residues 53, 98, 128, 134 and 176. N-deglycosylation increased aggregation and reduced solubility of the receptor but did not affect its IL-4 binding activity. These observations provide preliminary insights into the role of N-linked oligosaccharides in IL-4 receptor biosynthesis and function at the cell surface.

Amino Acid Sequence↗

PubMed1995

Plasminogen kringle 4 binds the heptapeptide fragment 44-50 of the plasminogen N-terminal peptide.

The interaction between the plasminogen kringle 4 module and a synthetic peptide corresponding to the tryptic heptapeptide fragment Ala-Phe-Gln-Tyr-His-Ser-Lys (AFQYHSK), segment 44-50 of the plasminogen N-terminal peptide (Wiman and Wallén, Eur J Biochem 1975; 50:489-494), has been investigated by 1H-NMR spectroscopy. AFQYHSK, as well as the shorter fragments thereof, FQYHSK, QYHSK and YHSK, all bound to kringle 4 with equilibrium association constant (Ka) values ranging between 2.5 and 8.5 mM-1. The NMR evidence also indicates that binding is mediated by the canonical kringle lysine binding site and involves the C-terminal Lys residue of the ligand peptide. The results (a) support a potential interaction between plasminogen Lys-binding kringles and the N-terminal activation peptide, and (b) unambiguously demonstrate the capability of such kringles to bind polypeptides ending with C-terminal lysine.

Amino Acid Sequence↗

PubMed1995

NonHodgkin's lymphoma of the male urethra.

Ten cases of malignant lymphoma of the female urethra have been reported. To our knowledge we report the first such case in a man who presented in acute urinary retention with a mass protruding from the urethral meatus. Multiple subcutaneous nodules developed over the anterior abdominal wall and a 3 x 3 cm. mass developed above the umbilicus. Wedge resection of this mass was consistent with large cell lymphoma. Treatment consisted of 2 courses of arabinoside C, doxorubicin and prednisone. Followup 6 months later showed no urethral or other recurrence. Local excision, radical excision, radiotherapy (external beam and intracavitary) and chemotherapy have been used with success in other cases.

Humans↗

PubMed1994

Expression of cellular retinol- and cellular retinoic acid-binding proteins in the rat cervical epithelium is regulated by endocrine stimuli during normal squamous metaplasia.

To determine the potential roles of retinoids in the growth and differentiation of the reproductive tract epithelium, we have studied the expression of the cellular retinol- and retinoic acid-binding proteins, CRBP I and CRABP I, in the reproductive tract of female rats. CRBP I and CRABP I gene expression have been examined in the oviduct, ovary, uterus, and particularly in the cervix, which normally undergoes a cyclical squamous metaplasia during the estrus cycle. CRBP I was expressed in all four tissues examined, whereas CRABP I was expressed predominantly in cervix and uterus. In the cervix, CRBP I was detected in all epithelial layers including the columnar epithelium but was greatly reduced in the superficial, cornified layers of the stratified squamous epithelium. CRABP I was localized to the basement membrane region of the epithelium with the strongest expression in the basal layer of epithelial cells. While the expression of CRBP I and CRABP I in the keratinizing exocervix changed during the estrus cycle, it remained constant in the incompletely keratinized endocervix. The highest levels of CRBP I were seen during anestrus and proestrus, and for CRABP I during proestrus. Both CRBP I and CRABP I levels fell to barely detectable levels during estrus and metestrus. Using estrogen repletion of ovariectomized rats, we found that CRABP I levels transiently increased during the early proliferative response to estrogen, whereas CRBP I levels gradually declined, becoming barely detectable by 24 to 48 hours. These results suggest that CRBP I and CRABP I play different roles in the cyclical squamous metaplasia normally occurring in this tissue and that hormonal control of CRBP I and CRABP I expression might modulate the retinoid responsiveness of the epithelium during this process.

Animals↗

PubMed1993

Carcinoma in female urethral diverticulum: case reports and review of management.

We report on 4 women ages 31 to 65 years with adenocarcinoma of urethral diverticulum. One patient presented with metastatic disease and died after refusing post-radiation surgery. The other 3 women were without evidence of disease 9 to 44 months after diverticulectomy with radiation (1) or radical surgery (2). Review of our 4 cases and 64 cases documented in the literature showed that irritative voiding symptoms and hematuria were the most common findings. A palpable urethral mass was described in only 56% of reported cases but was observed in all of our patients, with the smallest mass measuring 2 x 2 cm. Urethroscopy with biopsy is the most important diagnostic test. Aggressive treatment is appropriate in most patients, since local recurrence has been documented in 44% of those treated by diverticulectomy and/or radiation.

Adenocarcinoma↗

PubMed1993

Gastric pull-up by eversion stripping of oesophagus.

Gastric pull-up is a reliable method of one-stage reconstruction following total laryngopharyngoesophagectomy (TLPE). However, the technique of blunt finger dissection for extrapleural extraction of the oesophagus is liable to produce chest complications like pneumothorax. We report a series of 45 patients who underwent gastric pull-up using the technique of oesophageal extraction by stripping which produced virtually no thoracic complications. This simple technique has greatly reduced morbidity associated with gastric pull-up.

Anastomosis, Surgical↗

PubMed1993

Retinoic acid receptor, cytosolic retinol-binding and retinoic acid-binding protein mRNA transcripts and proteins in rat insulin-secreting cells.

To define the mechanism of vitamin A action at the beta-cell level, we tested for the presence of messenger RNA for retinoic acid receptors alpha, beta, and gamma; cytosolic retinol-binding protein; and cytosolic retinoic acid-binding protein in RINm5F cells, an insulin-secreting cell line, and determined whether cytosolic retinol-binding protein and cytosolic retinoic acid-binding protein are present in isolated purified normal rat beta-cells. Northern blot analyses showed two transcripts of retinoic acid receptor alpha messenger RNA (3.8 and 2.4 kb), one transcript of retinoic acid receptor messenger RNA (3.8 kb), and one transcript of cytosolic retinol-binding protein (0.9 kb) in RINm5F cells. Ribonuclease protection assays also showed the presence of cytosolic retinol-binding protein and cytosolic retinoic acid-binding protein in RINm5F cells. Quantitatively, cytosolic retinol-binding protein levels were 0.10 +/- 0.02 pg/micrograms total RNA. Using specific radioimmunoassays, normal isolated purified rat beta-cells contained CRBP (19.2 +/- 2.38) and cytosolic retinoic acid-binding protein (16 +/- 0.53 ng/10(6) cells). The presence of message for retinoic acid receptors alpha and gamma, cytosolic retinol-binding protein, cytosolic retinoic acid-binding protein, and the gene products of cytosolic retinol-binding protein and cytosolic retinoic acid-binding protein in insulin-secreting cells support a mechanism of vitamin A action and role for cytosolic and nuclear receptors at the beta-cell level similar to that suggested in nonendocrine cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Carcinoma of the rectal pouch following restorative proctocolectomy. Report of a case.

A case of adenocarcinoma developing in the pouch following restorative proctocolectomy is presented. This seems to be the third reported in the literature. The carcinoma developed from the remnants of precancerous rectal mucosa left in the muscular rectal cuff. The patient had been suffering from ulcerative colitis for 17 years prior to the development of the malignancy. He presented with features of subacute intestinal obstruction. Diagnosis was by sigmoidoscopic examination of the pouch and biopsy. He was treated with abdominoperineal resection of the pouch and rectum, followed by chemotherapy.

Adenocarcinoma↗

PubMed1991

The ileosigmoid knot.

The ileosigmoid knot (ISK) is a rare cause of intestinal obstruction. Unfamiliarity with the condition could have disastrous consequence at surgery. Over the past 20 years, we have encountered seven cases. Analyzing the data gathered from these, and on reviewing the literature, we found it possible to arrive at a preoperative diagnosis in two patients. Four patients were women, two of whom developed the obstruction in the postpartum period. One of the males was found to have an inflamed Meckel's diverticulum included in the knotting. The symptoms and the clinical findings were nonspecific. The characteristic x-ray findings of a double closed loop obstruction, was seen in only three patients. Resection of gangrenous bowel with anastomoses was feasible in four. Unlike in other series, primary anastomosis of the large gut was undertaken. There were two deaths early in the series. Guidelines to the management have been suggested.

Adult↗

PubMed1991

Cellular retinoic acid-binding protein messenger RNA: levels in rat tissues and localization in rat testis.

Studies were conducted to explore the tissue- and cell-specific regulation of cellular retinoic acid-binding protein (CRABP) expression in the rat. Two studies were carried out. The first explored the regulation of CRABP mRNA levels in selected rat tissues by dietary retinoid status, and the relationship between CRABP mRNA and protein levels in different tissues. The second examined the cellular localization of CRABP expression in the testis. In order to conduct these experiments, a cDNA encoding CRABP was isolated and characterized. The DNA sequence of the coding region had 96% identity with that of the mouse CRABP cDNA and encodes a protein identical to mouse and bovine CRABP. CRABP mRNA and protein levels were quantified in five tissues from normal, retinoid-deficient, and retinol-repleted rats. Tissue CRABP and CRABP mRNA levels were highly correlated (P less than 0.01) indicating that inter-tissue variability of CRABP levels mainly results from regulation of CRABP mRNA levels. Neither CRABP protein nor mRNA levels were affected by retinol deficiency, in marked contrast with results previously demonstrated with cellular retinol-binding protein (CRBP) (J. Lipid Res. 1990. 31: 821-829). 35S-labeled CRABP cRNA probes were used to localize CRABP mRNA within the testis of adult rats by in situ hybridization. CRABP mRNA was localized selectively in the periphery of the seminiferous tubules, primarily in type A spermatogonia. The localization of CRABP mRNA differs from that of CRABP protein, which is known to be enriched in maturing and more mature germinal cells. This difference suggests that CRABP in germ cells may be highly stable, remaining in the maturing germ cells without degradation long after CRABP mRNA levels have declined to very low levels. The specific localization of CRABP mRNA and protein presumably reflects the biological roles of retinoic acid in the development and/or later function of germinal cells.

Amino Acid Sequence↗

PubMed1991

Annular pancreas in adults (2 case reports).

Two cases of annular pancreas in adults are being reported. In the first case, a middle aged lady presented with duodenal obstruction and gastric ulcer. Anterior H. S. V. with posterior truncal vagotomy and isoperistaltic duodeno-jejunostomy relieved her symptoms. In the second case, a young girl presented with duodenal obstruction, severe wasting and gross dehydration. She had an uneventful recovery following a duodeno-jejunostomy.

Adolescent↗

PubMed1991

Vagal paraganglioma (2 case reports).

Paragangliomas are rare tumours of the head and neck and are a diagnostic challenge. Two cases of paragangliomas arising from the vagus are being reported. In the first case, an angiogram raised the possibility of intravagal tumour and exploration followed by biopsy confirmed the diagnosis. In the second case, it was a diagnostic surprise where exploration was done on a clinical suspicion of parotid swelling and on the table, the swelling was found to arise from the vagus nerve pushing the parotid gland laterally.

Adult↗

PubMed1990

Localization of cellular retinol-binding protein mRNA in rat testis and epididymis and its stage-dependent expression during the cycle of the seminiferous epithelium.

Anatomical localization of cellular retinol-binding protein (CRBP) mRNA was examined in normal rat testis and epididymis and also in retinoid-deficient rat testis. In situ hybridization was performed with 35S-labeled rat CRBP cRNA probes on frozen tissue sections. In normal testis, CRBP mRNA was mainly localized in the Sertoli cells and to some extent in peritubular cells. A distinct cyclic variation of the relative levels of hybridizable CRBP mRNA was observed during the spermatogenic cycle. The peak of CRBP mRNA content was seen in the stages of the cycle that preceded those in which peak CRBP protein content had been observed previously in our laboratory by immunohistochemistry. No appreciable amount of CRBP mRNA was observed in the interstitial space or in the lumen of the tubules. CRBP mRNA displayed the same anatomical localization in the retinoid-deficient testis, but the level of hybridizable CRBP mRNA was substantially reduced. A strong hybridization signal for CRBP mRNA was seen in proximal epididymis and was strikingly localized in the ductular epithelium. CRBP mRNA was not detectable in the distal portion of the epididymis. These studies provide information about the cell-specific expression of CRBP synthesis within the testis and epididymis and about its cyclic variation and regulation.

Animals↗

PubMed1990

Cellular retinol-binding protein messenger RNA levels in normal and retinoid-deficient rats.

A study was conducted to determine the levels of cellular retinol-binding protein (CRBP) mRNA and protein in various tissues of the rat, to explore relationship between CRBP mRNA and protein levels in different tissues, and to examine the effects of changes in retinol nutritional status on the tissue distribution and levels of CRBP mRNA. Previous studies have shown that tissue CRBP protein levels are reduced in totally retinoid-deficient rats, but are otherwise minimally affected by changes in retinoid status. Three groups of male rats were compared: normal controls, retinoid-deficient, and retinol-repleted deficient rats. CRBP mRNA levels were measured by RNase protection assay and CRBP protein levels by radioimmunoassay in seven tissues. High levels of both CRBP mRNA and CRBP protein were found in the proximal epididymis, kidney, and liver; lower levels were seen in lung, testis, spleen, and small intestine. Tissue CRBP mRNA and protein levels were highly correlated (P less than 0.01) with each other. Retinoid deficiency did not alter the levels of CRBP mRNA found in the proximal epididymis, kidney, and liver. In contrast, CRBP mRNA levels in the lung, testis, spleen, and small intestine were reduced substantially in retinoid-deficient rats, to values that were only 23% to 50% of the corresponding values in the tissues of control rats. After oral repletion with retinol (4-18 h earlier), CRBP mRNA levels for these latter four tissues were found to have risen to control or near-control levels. The suggestion is raised that retinol repletion may have directly induced the expression of the CRBP gene in these particular tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Captopril-related exfoliative dermatitis.

A patient with congestive heart failure and mild renal impairment developed exfoliative dermatitis following the addition of captopril to her therapy. The skin reaction responded to drug withdrawal and the administration of corticosteroids, though the patient subsequently succumbed to the complications of an incidental myocardial infarction. Recognition and prompt treatment of this potentially fatal dermatological crisis is stressed. The newer generation of angiotensin converting enzyme inhibitors may have a lesser propensity for cutaneous complications.

Captopril↗

PubMed1986

Proton magnetic resonance study of kringle 1 from human plasminogen. Insights into the domain structure.

The aromatic H NMR spectrum of the kringle 1 domain from human plasminogen has been investigated by proton Overhauser experiments, acid-base titration, and two-dimensional chemical shift correlated spectroscopy. Spin-echo and pH response experiments lead to the identification of the N-terminal Tyr-3 phenol ring signals. The connectivities among the tryptophanyl aromatic protons have been established and sets of singlet-doublet-triplet resonances stemming from each of the two indole groups sorted according to their common side chain origin. Similarly, the four histidyl singlets have been identified and paired per imidazole group. From their pH responses, it is indicated that a histidyl (His31) and a tryptophanyl (Trp-II) residue are placed in the neighborhood of carboxyl groups. The high-field chemical shifts observed for proton resonances of the ligand epsilon-aminocaproic acid upon binding to kringle 1 indicate that the ligand-binding site is rich in aromatic components. Overhauser experiments reveal that Leu46 is surrounded by a cluster of interacting aromatic side chains, which includes Trp25, Phe36, His41, Trp62, and Tyr64, and define a hydrophobic region contiguous to the kringle lysine-binding site. Relative internuclear distances have been estimated for aromatic H-atoms in the vicinity of Leu46 by reference to one of the latter's CH3 sigma, sigma' groups. Some of the connectives have previously been found for Leu46 in kringle 4 which further supports the idea of a common structure for the homologous domains.

Amino Acid Sequence↗

PubMed1985

Formic acid poisoning with suicidal intent: a report of 53 cases.

A report of 53 cases of formic acid ingestion with suicidal intention is presented. The patients were seen in one hospital in Kerala State over a 3 year period. Fifteen patients died and 38 patients survived. The pattern of clinical features seen is presented.

Acute Kidney Injury↗