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Biomedical subjects

S Nair

Publications and source records attributed to S Nair.

At least 73 records · Page 4Linked to original sources
PubMed2001

Changes in platelet glycoprotein receptors after smoking--a flow cytometric study.

Cigarette smoking is accepted to be one of the major factors which increase the risk of coronary artery disease, peripheral vascular disease and stroke. A number of studies have been carried out on the acute and chronic effects of tobacco smoking on platelet activation. An enhancing effect of high nicotine cigarette smoking on platelet aggregation has been reported. Since platelet receptors are involved in the final stage of platelet aggregation, the intention of this study was to investigate platelet receptors in acute and chronic smokers before and after smoking. Nineteen chronic smokers, 18 acute smokers and 18 healthy non-smoking controls were included in the present study. Platelet aggregation was carried out using ristocetin, adenosine diphosphate (ADP) and collagen both before and after smoking in acute and chronic smokers. Flow cytometric studies of platelets were carried out utilizing fluorescein isothiocyanate (FITC)-labelled anti-human fibrinogen antibody in unstimulated and ADP-stimulated platelets, FITC-labelled anti-GP IIb/IIa antibody, FITC-labelled anti-GP Ib/IX antibody and FITC-labelled P-selectin antibody. The intensity of fluorescence was graded into three groups and expressed in arbitrary units. The interesting data generated in the present work is that in vivo platelet activation occurs immediately after smoking a cigarette which is detected by using FITC-labelled anti-human fibrinogen antibody binding to platelet and by P-selectin expression. It is also quite evident from the present study that a significant number of circulating platelets are in the activated state in chronic smokers. Therefore this study suggests that smoking-induced platelet activation may be an important contributory mechanism for acute coronary events in smokers.

Adult↗
PubMed2001

Isolated intrahepatic biliary dilatation in a patient with acquired immune deficiency syndrome (AIDS): AIDS cholangiopathy versus incidental unilobar Caroli's disease.

We describe a case of possible monolobar Caroli's disease in a patient with acquired immune deficiency syndrome (AIDS) who presented with features of cholangitis. Diagnostic workup, which included endoscopic retrograde cholangiography, revealed focal intrahepatic biliary dilatation confined to the right lobe. The patient subsequently underwent right hepatic lobectomy. Pathology revealed multiple cysts filled with calculi and inflammation in the cyst walls. Special stain results for fungi and acid-fast organisms were negative. The presence of advanced AIDS in this patient raised the possibility of this being a possible manifestation of AIDS cholangiopathy.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Spontaneous fungal peritonitis (Candida glabrata) in a patient with cirrhosis.

We report a case of spontaneous fungal peritonitis in a patient with cirrhosis. A 70-year-old woman with cirrhosis secondary to autoimmune hepatitis was admitted with fever and abdominal distention. Paracentesis revealed neutrocytosis, and despite appropriate antibacterial coverage, no clinical improvement was noted and the ascitic fluid white cell count increased on repeat paracentesis. Two consecutive ascitic fluid cultures grew Candida glabrata, and antifungal therapy with amphotericin was initiated, pending sensitivity of the isolate. Because of worsening renal function, amphotericin was discontinued and itraconazole was started, as sensitivity of the isolate was then available. Antifungal therapy resulted in resolution of ascitic fluid neutrocytosis and culture negativity. However, the patient's renal function continued to deteriorate, necessitating hemodialysis. Despite multiple courses of antibiotics, she died of fulminant sepsis and multiorgan failure.

Aged↗
PubMed2001

Progressive gastrointestinal histoplasmosis leading to colonic obstruction two years after initial presentation.

A 37-yr-old man from Ecuador presented with abdominal pain, diarrhea, and weight loss. Endoscopy revealed duodenal histoplasmosis. The patient improved with antifungal therapy but was readmitted 2 yr later with diarrhea and fever. Colonoscopy revealed histoplasmosis lesions, including a constricting transverse colon lesion. The patient refused surgery and died of colonic perforation. We discuss the diagnosis and management of gastrointestinal histoplasmosis in this report.

Adult↗
PubMed2001

Postoperative morbidity, mortality, costs, and long-term survival in severely obese patients undergoing orthotopic liver transplantation.

OBJECTIVE: Severely obese patients who undergo orthotopic liver transplantation are likely to have higher morbidity, mortality, costs, and a lower long-term survival. METHODS: This case-control study was done at a university hospital. One hundred twenty-one consecutive patients who underwent liver transplantation between 1994 and 1996 were studied. Severe obesity was defined as body mass index (BMI) more than 95th percentile (>32.3 for women and >31.1 for men), and moderate obesity was defined as BMI between 27.3 and 32.3 for women and 27.8 and 31.1 for men. The outcome measures were intraoperative complications, postoperative complications (wound infections, bile leak, vascular complications), length of hospital stay, costs of transplantation, and long-term survival RESULTS: The baseline characteristics, UNOS status, and cause of liver disease at the time of transplantation were similar in severely obese (n = 21, BMI = 37.4+/-4.8 kg/m2), obese (n = 36, BMI 28.7+/-0.9 kg/m2), and nonobese patients (n = 64, BMI 23.8+/-2.5 kg/m2). The intraoperative complications and transfusion requirements were similar in all three groups. The postoperative complications such as respiratory failure (p = 0.009) and systemic vascular complications (p = 0.04) were significantly higher in severely obese patients. The overall perioperative complication rate was 0.61 (39 of 64 patients) in nonobese patients, 0.77 (28 of 36 patients) in obese patients, and 1.43 (30 of 21 patients) in severely obese patients (p = 0.01). Infections were the leading cause of death in all groups accounting for 57-66% of deaths. The length of hospital stay was significantly higher in obese patients. The hospital costs of transplantation were higher ($30,000-$40,000) in severely obese patients than in nonobese patients. The long-term patient survival was similar between the groups (Kaplan-Meier analysis). CONCLUSIONS: Despite higher postoperative complications, severely obese patients have an acceptable long-term survival, which is comparable to nonobese patients. The cost of transplantation is higher among severely obese patients. There was no increased incidence of cardiovascular mortality among severely obese patients during the follow-up period.

Adult↗
PubMed2001

Obesity and female gender increase breath ethanol concentration: potential implications for the pathogenesis of nonalcoholic steatohepatitis.

OBJECTIVES: Similarities between histological features of alcoholic hepatitis and obesity-related liver disease suggest a common pathogenic mechanism. Because intestinal bacteria can produce ethanol, it is conceivable that intestinally derived alcohol may contribute to fatty liver disease. An indirect way of measuring endogenous ethanol is to measure the breath ethanol concentration. In a previous study in ob/ob mice, breath ethanol decreased with a course of non-absorbable antibiotics, suggesting that the ethanol is derived from intestinal bacterial flora. The aims of this study were 1) to determine whether alcohol can be detected in the breath of human subjects, and 2) to assess whether there is any correlation between ethanol and obesity in patients with nonalcoholic steatohepatits (NASH) and control subjects without known liver disease. METHODS: Breath ethanol concentration was determined in 21 patients with biopsy-proven NASH and in 10 control subjects by gas chromatography. An abnormal breath ethanol level was defined as two standard deviations above the mean value of the breath ethanol of lean controls. RESULTS: Minute quantities of ethanol were detected in the breath of human subjects who had not consumed alcohol in the recent past. Patients who were obese were more likely to have higher breath ethanol concentrations. Women also had higher breath alcohol than men. However, there was no difference between patients with NASH and controls. Severity of liver disease, as evidenced by cirrhosis, did not influence the breath ethanol concentration. CONCLUSIONS: Higher breath ethanol concentrations are observed in obese subjects than in leaner ones. It is possible that intestinally derived ethanol may contribute to the pathogenesis of NASH.

Adult↗
PubMed2001

Serum and colon mucosa micronutrient antioxidants: differences between adenomatous polyp patients and controls.

OBJECTIVES: Micronutrient antioxidants, by virtue of their free radical scavenging properties, are potential chemopreventive agents against colon cancer. Yet, little is known about the actual concentration of these antioxidants in colonic mucosa. It is also not known whether a relationship exists between serum and mucosal tissue antioxidant levels. Previous studies evaluating the occurrence of polyps after supplementation with vitamin E and beta-carotene have yielded mixed results. The aim of this study was to determine the concentrations of seven micronutrient antioxidants (alpha- and gamma-tocopherol, lutein, beta-cryptoxanthin, lycopene, and alpha- and beta-carotene) in colonic mucosa and to determine whether serum levels of each antioxidant could predict levels of that antioxidant in the right and left colon of patients with normal mucosa or in those with adenomatous polyps. METHODS: Mucosal tissue concentrations and serum levels of antioxidants were determined in 10 patients with adenomatous polyps and 15 control subjects (GI patients with normal colonic mucosa). Mucosal tissue samples were obtained from both the right and left colon in all patients. RESULTS: Patients with polyps similar serum antioxidant status similar to that of control. However, polyp patients had significantly lower concentrations of all seven antioxidants in both the right (p < 0.0070) and left colon (p < 0.0026) than did controls. Finally, serum antioxidant levels predict right and left colon antioxidant levels in controls but not in patients with polyps. CONCLUSIONS: Patients with adenomatous polyps have low levels of micronutrient antioxidants in their colon mucosa. Because the serum levels of these antioxidants were similar in controls and polyp patients, our findings suggest an increased level of free radical activity in patients with polyps compared to normal subjects.

Adenomatous Polyps↗
PubMed2001

Polymorphisms flanking the mariner integration sites in the rice gall midge (Orseolia oryzae Wood-Mason) genome are biotype-specific.

In an effort to study genome diversity within and between the Indian biotypes of the Asian rice gall midge, Orseolia oryzae, a major insect pest of rice, we made use of mariner transposable element integration site polymorphisms. Using degenerate primers, the design of which is based on mariner sequences, we amplified a ca. 450 bp mariner sequence from the rice gall midge. The mariner sequence showed homology with that of a mariner element isolated from the Hessian fly, Mayetiola destructor, a major dipteran pest of wheat. Southern hybridization, using this mariner fragment as a probe, revealed that the mariner elements are moderately to highly repetitive in the rice gall midge genome. Based on the sequence information of this 450-bp PCR-amplified fragment, outward-directed primers were designed and used in an inverse PCR (iPCR) to amplify the DNA flanking the conserved regions. To study the regions flanking the mariner integration sites, we employed a novel PCR-based approach: a combination of sequence specific amplification polymorphism (SSAP) and amplified fragment length polymorphism (AFLP). The outward-directed mariner-specific primer was used in combination with adapter-specific primers with 1-3 selective nucleotides at their 3' ends. The amplification products were resolved on an agarose gel, Southern-transferred onto nylon membranes, and probed with the iPCR fragment. Results revealed biotype-specific polymorphisms in the regions flanking the mariner integration sites, suggesting that mariner elements in the rice gall midge may be fixed in a biotype-specific manner. The implications of these results are discussed in the context of biotype differentiation.

Amino Acid Sequence↗
PubMed2001

Genetic diversity of Bradyrhizobium strains isolated from Arachis hypogaea.

Rhizobia are used exclusively in agricultural systems for enhancing the ability of legumes to fix atmospheric nitrogen. Knowledge about the indigenous population is necessary for the selection and application of inoculant strains. In this study, we have assessed the genetic diversity of Bradyrhizobium strains isolated from the host plant, Arachis hypogaea along the coastline of Tamil Nadu. Different populations collected from varying environmental conditions were analysed for salt and pH tolerance. Genetic diversity among the strains was studied using RAPD markers and PCR-RFLP of 16S rDNA and nifD genes. The approaches used in this study yielded consistent results, which revealed a high degree of heterogeneity among strains and detection of two distinct genetic groups.

Arachis↗
PubMed2001

Venous thromboembolism in young patients from western India: a study.

The goal of this article is to study the association of known markers of thrombophilia with venous thrombosis in young patients (< 45 years) from the Western part of India. A prospective study of 432 patients (252 males and 180 females, age 1-45 years) was conducted between 1994 and 2000 (6 years). The diagnosis was confirmed in all the patients by ultrasound with Doppler or by a computed tomograph (CT) scan of the brain with or without contrast depending on the case. Detailed clinical examination, and family history was taken to establish recurrent thrombosis and familial occurrence of thrombosis. The markers studied were protein C, protein S, antithrombin (AT) III, factor V Leiden mutation, prothrombin gene G20210A polymorphism, and the thermolabile MTHFR variant C677T polymorphism, using appropriate techniques. Lupus inhibitor was tested in the first 72 patients using Dilute Russel Viper Venom Time (DRVVT) test, and anticardiolipin antibodies were tested by enzyme-linked immunosorbent assay. Protein C, protein S, and AT III deficiency was detected in 9.5%, 6.5%, and 2.6%, respectively, among the patients. Anticardiolipin antibody was present in 9.9% of the patients, whereas lupus anticoagulant was present in 8.3% of patients; factor V Leiden mutation was detected in 3% of patients; thermolabile variant of MTHFR C677T polymorphism was present in 14.9% of patients with 1.2% homozygotes. Prothrombin G20210A polymorphism was not detected in any sample in this population. One hundred and four patients of 432 (24.9%) had recurrent attacks of thrombosis without any proximate precipitating cause, whereas 7.5 % of the patients had another close member of the family with a history of deep venous thrombosis. Eighty-six members from 28 families (out of 32 families giving family history of thrombosis) were investigated and found to have protein C and protein S deficiency in seven each; factor V Leiden was present in 6, and MTHFR C677T polymorphism was present in 5 cases. Hence, 25 of 86 members (28%) from the family of patients with familial history deep venous thrombosis had positive markers for thrombophilia. Thus, we could show that in young patients presenting with thrombosis, at least 34% of them had a demonstrable cause for thrombophilia. Prothrombin gene polymorphism G20210A seems to be nonexistent in our population and AT III deficiency also appears to be low compared to other markers of thrombophilia. There is a high prevalence of variant MTHFR C677T in our series, but the incidence of MTHFR C677T in our general population is also high. Hence, the significance of this finding in our cases of deep venous thrombosis remains to be seen, but we did not see any homozygotes when we tested 70 randomly selected asymptomatic persons, whereas in the present series, 1.8% of the patients had homozygosity for the MTHFR C677T polymorphism.

Adolescent↗
PubMed2001

Solitary metastasis from occult follicular carcinoma of the thyroid mimicking trigeminal neurinoma--case report.

A 50-year-old woman presented with an extremely uncommon case of solitary metastasis from follicular carcinoma of the thyroid, which presented clinically as trigeminal neurinoma. Neuroimaging detected a tumor in the right petrous apex, which was removed surgically. Histological examination showed metastatic follicular carcinoma of the thyroid. However, no primary tumor was detected by various investigations. The tumor recurred twice, and was treated surgically both times. The patient finally agreed to adjuvant therapy for the suspected primary. Radiotherapy was performed followed by complete thyroidectomy. Examination of the gross specimen found the tumor nodule. Clinically significant metastasis can arise from histologically benign and silent follicular thyroid neoplasms.

Adenocarcinoma, Follicular↗
PubMed2001

Detection of amplified int-2/FGF-3 gene in primary breast carcinomas using differential polymerase chain reaction.

Amplification of int-2/FGF-3 gene was investigated by differential polymerase chain reaction (dPCR) in 440 archival primary breast carcinoma tissues. Of these, 23 were comedo ductal carcinoma in situ (DCIS), 18 were non-comedo DCIS, 41 were comedo DCIS with adjacent invasive ductal carcinomas, 19 were non-comedo DCIS with adjacent invasive ductal carcinomas, 270 were invasive ductal carcinomas, 33 were invasive lobular carcinomas, 21 were colloid carcinomas and 15 were medullary carcinomas. Int-2 was amplified in 22% (96/440) of the primary breast carcinomas. It was shown that int-2 was amplified in 13% (3/23) of the comedo DCIS, 17% (7/41) of the comedo DCIS and 29% (12/41) of the adjacent invasive ductal carcinomas, 26% (71/270) of the invasive ductal carcinomas, 18% (6/33) of the invasive lobular carcinomas, 10% (2/21) of the colloid carcinomas and 13% (2/15) of the medullary carcinomas. In contrast, int-2 was not amplified in non-comedo DCIS and invasive ductal carcinomas with adjacent non-comedo DCIS lesions. A significant association was observed between int-2 amplification in the in situ components and adjacent invasive lesion (P<0.05). All tumors with int-2 amplification in the in situ lesions (7/7) also demonstrated same degree of amplification in the adjacent invasive components. However, 9% (5/53) of the tumors with no amplified int-2 gene in the in situ components showed int-2 amplification in the adjacent invasive lesions. A significant relationship was noted between amplification of int-2 and lymph node metastases (P<0.05) and poorly differentiated tumors (P<0.05) but not with estrogen receptor status (P>0.05) and proliferation index (Ki-67 and PCNA) (P>0.05). In Malaysia, majority of the patients belong to younger age group (<50 years old) but a comparison of the age groups showed that the amplification of int-2 was not statistically associated with patient age (P>0.05). These observations indicate that amplification of int-2 tends to strengthen the view that int-2 may have the potential to be an indicator of poor prognosis regardless of the age of the patient. Moreover, the presence of int-2 amplification in preinvasive, preinvasive and adjacent invasive lesions, and invasive carcinomas suggest that int-2 could be a marker of genetic instability occurring in early and late stages of tumor development.

Adult↗
PubMed2001

Dissecting intracranial vertebral artery aneurysms.

Dissecting aneurysms of the intracranial arteries are exceedingly rare vascular lesions that can produce acute cerebral or brain stem infarction in young healthy adults. They carry a high mortality rate. Two cases of dissecting vertebral artery aneurysms that presented with bleed, were successfully operated by trapping and excision of the dissecting segment. Both dissecting aneurysms were located distal to PICA origin. Both the patients developed post operative lower cranial nerve paresis and one developed lateral medullary syndrome, which improved subsequently. Dissecting aneurysms presenting with bleed should be surgically managed by trapping and excising the involved segment sparing the PICA origin or by interventional radiological techniques. Revascularisation procedures should be considered in addition to trapping of the main vertebral segment if PICA is involved in the trapped segment. The diagnostic and therapeutic difficulties associated with dissecting vertebral artery aneurysms and the controversies regarding their management have been reviewed.

Adult↗
PubMed2001

Mixed tumour of schwannoma and meningioma in a patient with neurofibromatosis-2 : a case report.

The co-existence of schwannoma and meningioma as a mixed intracranial tumour is uncommon and so far only eight cases have been published in the literature. Because of rarity, we report a unique case of mixed tumour having schwann cell and meningeal components, in a patient with neurofibromatosis type -2 (NF-2). The possible mechanisms for the occurrence of these mixed tumours are discussed.

Adult↗
PubMed2000

Preoperative mobilization of circulating dendritic cells by Flt3 ligand administration to patients with metastatic colon cancer.

PURPOSE: To evaluate preoperative dendritic cell (DC) mobilization and tumor infiltration after administration of Flt3 ligand (Flt3L) to patients with metastatic colon cancer. PATIENTS AND METHODS: Twelve patients with colon cancer metastatic to the liver or lung received Flt3L (20 microg/kg/d subcutaneously for 14 days for one to three cycles at monthly intervals) before attempted metastasectomy. The number and phenotype of DCs mobilized into peripheral-blood mononuclear cells (PBMCs) were evaluated by flow cytometry. After surgical resection, metastatic tumor tissue was evaluated for DC infiltration. In vivo immune responses to recall antigens were measured. RESULTS: After Flt3L administration, on average, the total number of leukocytes in the peripheral blood increased from 5.9 +/- 1.0 x 10(3)/mm(3) to 11.2 +/- 3.8 x 10(3)/mm(3) (mean +/- SD, P: =. 0001). The percentage of CD11c(+)CD14(-) DCs in PBMCs increased from 2.4% +/- 1.8% to 8.8% +/- 4.7% (P: =.004). Delayed-type hypersensitivity (DTH) responses to recall antigens (CANDIDA:, mumps, and tetanus) showed marginally significant increases in reactivity after Flt3L administration (P: =.06, P: =.03, and P: =.08, respectively). An increase in the number of DCs was observed at the periphery of the tumors of patients who received Flt3L compared with those of patients who had not. CONCLUSION: Flt3L is capable of mobilizing DCs into the peripheral blood of patients with metastatic colon cancer and may be associated with increases in DC infiltration in the peritumoral regions. Flt3L mobilization is associated with a trend toward increased DTH responses to recall antigens in vivo. The use of Flt3L to increase circulating DCs for cancer immunotherapy should be considered.

Adjuvants, Immunologic↗
PubMed2000

A genetic linkage map of the baboon (Papio hamadryas) genome based on human microsatellite polymorphisms.

A first-generation genetic linkage map of the baboon (Papio hamadryas) genome was developed for use in biomedical and evolutionary genetics. Pedigreed baboons (n = 694) were selected from the breeding colony maintained by the Southwest Foundation for Biomedical Research. To facilitate comparison with the human genome, the baboon linkage map consists primarily of human microsatellite loci amplified using published human PCR primers. Genotypes for 325 human microsatellites and 6 novel baboon microsatellites were used in linkage analyses performed with the MultiMap expert system. The resulting sex-averaged meiotic recombination map covers all 20 baboon autosomes, with average spacing among loci of 7.2 cM. Direct comparison among homologous (orthologous) loci reveals that, for 7 human autosomes, locus order is conserved between humans and baboons. For the other 15 autosomes, one or more rearrangements distinguish the two genomes. The total centimorgan distances among homologous markers are 28.0% longer in the human genome than in the baboon, suggesting that rates of recombination may be higher in humans. This baboon linkage map is the first reported for any nonhuman primate species and creates opportunities for mapping quantitative trait loci in baboons, as well as for comparative evolutionary analyses of genome structure.

Animals↗