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Biomedical subjects

A Nair

Publications and source records attributed to A Nair.

At least 19 recordsLinked to original sources
PubMed2002

Effect of aflatoxins on testicular steroidogenesis and amelioration by vitamin E.

The potential of aflatoxin to affect testicular steroidogenesis and its amelioration by vitamin E was assessed in the present investigation. Oral administration of aflatoxin (25 and 50 microg/animal/day) for 45 days to adult mice caused, as compared with control, a dose-dependent significant rise in cholesterol content. However, the activities of 3beta- and 17beta-hydroxysteroid dehydrogenases and serum testosterone levels were significantly reduced in aflatoxin-treated mice as compared with the controls. Pretreatment with vitamin E (2 mg/animal/day, orally) significantly ameliorated aflatoxin-induced changes as compared with aflatoxin treatment alone. The present investigation clearly indicates that vitamin E ameliorates aflatoxin-induced changes in steroidogenesis.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

Assessing spectral algorithms to predict atherosclerotic plaque composition with normalized and raw intravascular ultrasound data.

Spectral analysis of backscattered intravascular ultrasound (IVUS) data has demonstrated the ability to characterize plaque. We compared the ability of spectral parameters (e.g., slope, midband fit and y-intercept), computed via classic Fourier transform (CPSD), Welch power spectrum (WPSD) and autoregressive (MPSD) models, to classify plaque composition. Data were collected ex vivo from 32 human left anterior descending coronary arteries. Regions-of-interest (ROIs), selected from histology, comprised 64 collagen-rich, 24 fibrolipidic, 23 calcified and 37 calcified-necrotic regions. A novel quantitative method was used to correlate IVUS data with corresponding histologic sections. Periodograms of IVUS samples, identified for each ROI, were used to calculate spectral parameters. Statistical classification trees (CT) were computed with 75% of the data for plaque characterization. The remaining data were used to assess the accuracy of the CTs. The overall accuracies for normalized spectra with CPSD, WPSD and MPSD were, respectively, 84.7%, 85.6% and 81.1% (training data) and 54.1%, 64.9% and 37.8% (test data). These numbers were improved to 89.2%, 91.9% and 89.2% (training) and 62.2%, 73% and 59.5% (test) when the calcified and calcified-necrotic regions were combined for analysis. Most CTs misclassified a few fibrolipidic regions as collagen, which is histologically acceptable, and the unnormalized and normalized spectra results were similar.

Adult↗
PubMed2001

High resolution protein localization using soft X-ray microscopy.

Soft X-ray microscopes can be used to examine whole, hydrated cells up to 10 microm thick and produce images approaching 30 nm resolution. Since cells are imaged in the X-ray transmissive "water window", where organic material absorbs approximately an order of magnitude more strongly than water, chemical contrast enhancement agents are not required to view the distribution of cellular structures. Although living specimens cannot be examined, cells can be rapidly frozen at a precise moment in time and examined in a cryostage, revealing information that most closely approximates that in live cells. In this study, we used a transmission X-ray microscope at photon energies just below the oxygen edge (lambda = 2.4 nm) to examine rapidly frozen mouse 3T3 cells and obtained excellent cellular morphology at better than 50 nm lateral resolution. These specimens are extremely stable, enabling multiple exposures with virtually no detectable damage to cell structures. We also show that silver-enhanced, immunogold labelling can be used to localize both cytoplasmic and nuclear proteins in whole, hydrated mammary epithelial cells at better than 50 nm resolution. The future use of X-ray tomography, along with improved zone plate lenses, will enable collection of better resolution (approaching 30 nm), three-dimensional information on the distribution of proteins in cells.

3T3 Cells↗
PubMed2001

Novel ABA- and dehydration-inducible aldehyde dehydrogenase genes isolated from the resurrection plant Craterostigma plantagineum and Arabidopsis thaliana.

In order to identify genes that are critical for the ABA-dependent stress response in the resurrection plant Craterostigma plantagineum, a gene was isolated with homology to class 3 variable substrate aldehyde dehydrogenases (ALDH). The C. plantagineum gene Cp-ALDH constitutes a novel class of plant ALDHs. In a search for corresponding genes from Arabidopsis thaliana, Ath-ALDH3 and Ath-ALDH4 were isolated, showing 70% and 80% similarity to Cp-ALDH. Phylogenetically, the Cp- and Ath-ALDH3 and -ALDH4 proteins are closely related to aldehyde dehydrogenases from bacteria and mammalian species and are separated from known plant ALDHs and betaine-aldehyde dehydrogenases (BADH). Cp-ALDH transcript and polypeptide are up-regulated in vegetative tissues and callus in response to dehydration or ABA-treatment. Ath-ALDH3 expression was induced in response to dehydration and ABA treatment, while Ath-ALDH4 is constitutively expressed at a low level. Recombinant Cp-ALDH protein oxidizes nonanal, propionaldehyde and acetaldehyde, with Km values of 2.2 microm, 0.27 mm and 3.23 mm, respectively, in an NAD-dependent manner. Immunogold electron microscopy shows that Cp-ALDH is localized in plastids.

Abscisic Acid↗
PubMed2001

A 4- to 10-year follow-up study of the Tricon-M noncemented total knee replacement.

This study reviews the clinical and radiographic results of 207 consecutive noncemented Tricon-M (Smith & Nephew Inc, Memphis, Tenn) total knee replacements (TKRs) in 189 patients. The patella was surfaced in 119 cases, and mean follow-up was 8 years (range: 4-10 years). At final follow-up, mean Hospital for Special Surgery score improved 45 points in 187 cases. Survivorship, with failure defined as the need for revision, was 98% at 4 years, 97% at 7 years, 94% at 8 years, and 90% at 10 years. Twenty-one (11.3%) patients went on to revision. Results for overweight and obese patients did not differ significantly from normal-weight patients. The noncemented Tricon-M TKR prosthesis yields acceptable results; however, patella surfacing and the use of a tibial polyethylene insert > or = 12 mm thick are recommended.

Adult↗
PubMed2001

Primary papillary carcinoma in a thyroglossal cyst.

Papillary carcinoma arising in a thyroglossal cyst is rare. There is controversy regarding optimum management. We report a case managed by Sistrunk's procedure and external radiotherapy and review the literature on the subject.

Adult↗
PubMed2001

Ameliorative effect of vitamin E on aflatoxin-induced lipid peroxidation in the testis of mice.

AIM: To evaluate the ameliorative effect of vitamin E on aflatoxin-induced lipid peroxidation in the testis. METHODS: Adult male albino mice were orally administered 25 or 50 microg of aflatoxin in 0.2 mL olive oil per d for 45 d. The testis was isolated, blotted free of blood and processed for biochemical analysis. RESULTS: There was a dose-dependent significantly higher lipid peroxidation in the testis of aflatoxin treated mice than in the controls. The levels of non-enzymatic antioxidants such as glutathione, total and reduced ascorbic acid, as well as the activities of enzymatic antioxidants, such as superoxide dismutase, glutathione peroxidase and catalase were significantly lower in the testis of aflatoxin treated mice. Vitamin E (2 mg/d per animal; orally) pretreatment significantly ameliorates the aflatoxin-induced lipid peroxidation which could be due to higher enzymatic and non-enzymatic antioxidants in the testis of mice as compared with those given aflatoxin alone. CONCLUSION: Vitamin E pretreatment significantly ameliorates aflatoxin-induced lipid peroxidation in the testis of mice.

Aflatoxins↗
PubMed2001

Vitamin E ameliorates aflatoxin-induced biochemical changes in the testis of mice.

AIM: To assess the effect of aflatoxin on biochemical changes in the testis of mice and the possibility of amelioration by vitamin E treatment. METHODS: Adult male albino mice were orally administered with 25 or 50 microg of aflatoxin/animal/day (750 or 1500 microg/kg body weight) for 45 days. The testis was isolated and processed for biochemical analysis. RESULTS: There was a significant, dose-dependent reduction in DNA, RNA, protein, sialic acid contents and the activities of succinic dehydrogenase, adenosine triphosphatase and alkaline phosphatase in the testis of aflatoxin-treated mice as compared to the vehicle control. However, the acid phosphatase activity was significantly increased in the aflatoxin-treated mice. Vitamin E (2 mg/animal/day) treatment significantly ameliorated the aflatoxin-induced changes, except the acid and alkaline phosphatase activities in the high dose group. CONCLUSION: Vitamin E treatment ameliorates the aflatoxin-induced changes in the testis of mice.

Acid Phosphatase↗
PubMed2000

Comparison of human adult and fetal expression and identification of 535 housekeeping/maintenance genes.

Gene expression levels of about 7,000 genes were measured in 11 different human adult and fetal tissues using high-density oligonucleotide arrays to identify genes involved in cellular maintenance. The tissues share a set of 535 transcripts that are turned on early in fetal development and stay on throughout adulthood. Because our goal was to identify genes that are involved in maintaining cellular function in normal individuals, we minimized the effect of individual variation by screening mRNA pooled from many individuals. This information is useful for establishing average expression levels in normal individuals. Additionally, we identified transcripts uniquely expressed in each of the 11 tissues.

Adult↗
PubMed1999

Phaeochromocytoma: experience from a referral hospital in southern India.

BACKGROUND: Phaeochromocytoma has been traditionally called the 'Tumour of Tens'. Many investigators have reported the prevalence of extra-adrenal phaeochromocytoma to be more than 10%. METHODS: All consecutive adult patients diagnosed to have phaeochromocytoma by the departments of endocrinology and surgical endocrinology of the Christian Medical Hospital, India, over a period of 10 years from 1988 to 1998, were included in the study. RESULTS: A total of 30 patients were diagnosed to have phaeochromocytoma. Extra-adrenal phaeochromocytoma accounted for 26.6% of cases, Ten per cent of cases were bilateral, 6.6% were malignant and one patient had a familial tumour (multiple endocrine neoplasia IIB). The tumours were localized pre-operatively in all patients. Multicentric extra-adrenal tumours were not found in this series. All patients except one were explored by the anterior transperitoneal approach. Persistent hypertension was noted in 30% of patients. CONCLUSIONS: Our series shows a higher prevalence (26.6%) of extra-adrenal tumours than the traditionally described 10%. With accurate pre-operative localization, a transperitoneal approach may not be necessary. The laparoscopic approach needs to be evaluated in light of these findings.

Adrenal Gland Neoplasms↗
PubMed1998

Sacral hydatidosis: value of MRI in the diagnosis.

We present a case of primary hydatid disease of the sacrum. The diagnosis was made on MR imaging obtained to evaluate the spine for recurrent disc disease. The patient had previously undergone laminectomy elsewhere for L4-5 radiculopathy. Ultrasound-guided aspiration and visualisation of scolices confirmed the diagnosis. No other site of involvement was found.

Adult↗