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S Nair

Publications and source records attributed to S Nair.

At least 37 records · Page 2Linked to original sources
PubMed2003

The modified endoscopic Lothrop procedure in the treatment of complicated chronic frontal sinusitis.

The purpose of this study was to evaluate the modified endoscopic Lothrop procedure in the management of complicated frontal sinus disease which has breached the confines of the sinus walls and extended into the cranial cavity or orbit. Fourteen patients with radiological evidence of 17 complications of frontal sinus disease presented over a 23-month period. CT scan and MRI scans revealed the presence of posterior table erosion and extension of the frontal sinus disease into the anterior cranial fossa in 10 patients. In addition, seven patients had intraorbital complications, with three patients having both intracranial and orbital complications. All patients underwent a modified endoscopic Lothrop procedure as part of the management of the complication. In addition, one patient required an orbital abscess drainage and repair of an encephalocele, with a second patient requiring drainage of an orbital subperiosteal abscess. At follow-up, all patients were asymptomatic and had patent frontal sinus ostia. Follow-up ranged from 8 months to 38 months with a median of 25 months. Three patients required a revision of their frontal ostium. Two patients had allergic fungal sinusitis with aggressive polyp recurrence and ostial re-stenosis while one patient developed recurrent orbital infections from a retained frontal sinus cell. Currently, all have patent ostia, with an average size of 14.6 x 11 mm. The modified endoscopic Lothrop procedure is an effective form of treatment in the management of complicated frontal sinus disease. The results are comparable to those achieved with other surgical approaches such as the osteoplastic flap with obliteration.

Adolescent↗
PubMed2003

Acute stress increases calcium current amplitude in rat hippocampus: temporal changes in physiology and gene expression.

Activation of hippocampal glucocorticoid receptors in vitro increases calcium current amplitude through a process requiring DNA binding of receptor homodimers. We here investigated (i). whether similar increased calcium currents also occur following in vivo glucocorticoid receptor activation due to stress and (ii). if so, whether this can be explained by increased expression of calcium channel subunits. Rats were exposed to a novelty stress; some of the animals were pretreated with a glucocorticoid receptor antagonist. In subsequently prepared hippocampal slices, calcium currents were recorded from identified CA1 pyramidal neurons, after which RNA was collected, linearly amplified and hybridized with cDNA clones. Glucocorticoid receptor activation due to novelty exposure was associated with large total peak calcium currents and high-threshold noninactivating currents. Low-threshold calcium currents were not affected. Large total peak and noninactivating current amplitudes were also seen when animals received a more severe stressor, i.e. additional ether exposure. In the stressed groups, the total peak and high-threshold calcium current gradually increased with time resulting in a significant enhancement at >or=3 h after stress exposure. In the same cells, the summated (relative) RNA expression of various alpha1 calcium channel subunits was only transiently enhanced, prior to the functional changes. These data indicate that in vivo activation of glucocorticoid receptors due to stress gradually increases specific calcium current components. Prior to the functional change, increased expression of calcium channel subunits was observed, suggesting that the enhanced function could be explained by transcriptional regulation of the channels.

Analysis of Variance↗
PubMed2003

Platelet function tests using platelet aggregometry: need for repetition of the test for diagnosis of defective platelet function.

Four hundred and ninety seven patients were referred to our center for platelet aggregation studies because of spontaneous mucocutaneous bleeds. All these patients had normal complete blood count, platelet count and peripheral smears except in ten patients of Bernard Soulier Syndrome where platelet count was marginally reduced in the presence of giant platelets. Two hundred and eighty patients were found to have normal platelet aggregation to ADP, collagen, ristocetin and arachidonic acid. Out of the remaining 217 patients, 62 patients were diagnosed to have Glanzmanns thrombasthenia, 10 Bernard Soulier Syndrome, 6 storage pool deficiencies, 7 cyclooxygenase deficiencies and 72 von Willebrand disease. In all the patients with GT and BSS, diagnosis was confirmed with flow cytometry using multiple monoclonal antibodies to GPIIb-IIIa and GPIb-IX. There were sixty patients where initial platelet aggregation studies showed reduced (<30%) aggregation to either ADP, collagen, ristocetin or arachidonic acid in its various combination, however in 12 such patients (20%) the platelet aggregation studies were normal on repetition. All our platelet aggregation studies were done only after assuring that the patient is not taking any medicine for at least 7-10 days which may affect the platelet function tests. The present study shows that single atypically abnormal platelet aggregation studies should always be repeated. Finally in 48/217 patients (22%) some aggregation abnormality to one or more of the agonists persisted, although we could not categorize these patients into any clear-cut platelet disorder. None of these 48 patients platelet associated immunoglobulin was increased by flow cytometry. It is possible that large number of patients from that disorder will finally prove to be some form of platelet secretory defect. In north India similar group of defect in a large number of patients have been reported as isolated PF3 abnormality or thrombasthenic thrombopathy.

Adenosine Diphosphate↗
PubMed2003

Validation of biokinetic models of Cs and I using their daily dietary intakes and organ contents in an adult Indian population.

The daily dietary intakes and total contents of Cs and I in skeletal muscle and thyroid, respectively, for an average Indian adult were estimated by determining their concentrations in the total cooked diet and tissue samples using instrumental neutron activation analysis. These data were then used to predict the biological half-lives of Cs and I and their radioactive counterparts for the Reference Indian Man. The predicted biological half-lives of Cs and I for Reference Indian Man were found to be comparable with the reported values for the ICRP Reference Man.

Administration, Oral↗
PubMed2003

False aneurysm of cavernous carotid artery and carotid cavernous fistula: complications following transsphenoidal surgery.

We present two cases of carotid injury during transsphenoidal surgery for pituitary adenoma. While in one of the cases it resulted in the formation of a false aneurysm of cavernous carotid artery, in the other patient, a carotid cavernous fistula (CCF) formed. The false aneurysm was managed by surgical trapping and the patient had an uneventful recovery. The CCF was initially managed with balloon embolization. The balloon got deflated and resulted in a false aneurysm with persistent CCF. This was occluded with Guglielmi Detachable Coils (GDC). The management options are discussed and relevant literature is reviewed. We emphasize the importance of an early cerebral angiography to know the status of the injured carotid artery and formation of false aneurysm / fistula.

Adenoma↗
PubMed2003

Intracranial aneurysmal bone cyst manifesting as a cerebellar mass.

A 17-year-old boy presented with symptoms of raised intracranial pressure for a month. Investigations revealed a large extra-cerebellar mass. The lesion was radically resected. It arose from the petrous bone. Histology revealed that the lesion was an aneurysmal bone cyst [ABC].

Adolescent↗
PubMed2003

Rhabdoid tumor of the thalamus.

Rhabdoid tumors of the central nervous system are uncommon tumors. About 188 cases have been reported in the literature so far. In this report, we describe a case of a rhabdoid tumor of the thalamus in a 35-year-old male patient. Light microscopic and immunohistochemical features are discussed and the relevant literature reviewed.

Adult↗
PubMed2003

Liponeurocytoma of the cerebellum--a case report.

We report the characteristic neuropathological features of a rare case of cerebellar liponeurocytoma in a 62-year-old female. The tumor has a low proliferative potential and carries a favorable prognosis.

Cerebellar Neoplasms↗
PubMed2003

Contemporary management of fibroids.

INTRODUCTION: More women are delaying child-bearing such that gynaecologists can no longer resort as frequently to definitive treatments, such as a hysterectomy, in the management of uterine fibroids. A review of newer conservative medical, radiological and surgical therapies and minimal access approaches to the organ-preserving myomectomy operation are discussed. MATERIALS AND METHODS: Data from published literature describing newer modalities of treatment and reviewing updated information of the impact of fibroids and myomectomy on fertility potential were collated. RESULTS: Medical treatments serve to retard the growth of fibroids temporarily and have short-term success in the amelioration of symptoms. Uterine artery embolisation is a novel non-surgical approach to debulking of uterine fibroids and the relieve of symptoms. Hysterectomy is a treatment choice that is curative. Laparoscopic hysterectomy carries a 3% risk of major complications compared to 1% via a laparotomy. Laparoscopic myomectomy is a viable alternative to open myomectomy but due diligence must be exercised in ensuring meticulous and secure myomectomy defect repair. The risk of uterine dehiscence has been reported to be about 0.5% which is comparable to that in traditional open myomectomy which has been somewhat understated. Hysteroscopic resection of submucous fibroids is very efficacious and preserves reproductive potential. This procedure and myomectomy of intramural fibroids associated with intracavitary distortion are clearly indicated as these types of fibroids have been implicated as a cause of infertility and pregnancy loss at least 2 to 3 times higher than controls. This relationship prevailed in patients undergoing assisted reproduction. CONCLUSION: The management of uterine fibroids has undergone a revolution in the past few decades with better understanding of its impact on fertility and technical advances in endoscopy and radiologic embolisation techniques and also pharmaceutical alternatives such as gonadotrophin-releasing hormone agonist and progesterone intrauterine contraceptive devices. Advances in molecular biology may provide an opportunity to manipulate receptors and cellular biology in order to arrest tumourigenesis altogether.

Adult↗
PubMed2002

Bacterial growth efficiency in the tropical estuarine and coastal waters of Goa, southwest coast of India.

Bacterial growth efficiency (BGE) is an index of organic carbon passing through bacteria in an aquatic system. BGE values of natural bacterioplankton assemblages were measured in tropical estuarine and adjacent coastal waters in Goa along the southwest coast of India. The BGE values for estuarine and coastal waters were 18 (+/-7.84%) and 11 (+/-4.19%), respectively. BGE in these waters were at the lower end of what is usually found in productive systems. This may be due to the high respiration rates. Further, it was observed that grazers also influenced BGE. As BGE was positively correlated with bacterial productivity, the observed variation in BGE was attributed to bacterial productivity. BGE was inversely related to C:N ratio, indicating a close coupling between the nature of the substrates and BGE. Being system-dependent, the variations in BGE at the two locations were dynamic and were regulated by the quality of the substrates. Therefore, a constant value for BGE would lead to error in carbon budgets in these waters.

Bacteria↗
PubMed2002

Diversity of azospirillum strains isolated from rice plants grown in saline and nonsaline sites of coastal agricultural ecosystem.

The diversity of indigenous Azospirillum spp. associated with rice cultivated along the coastline of Tamil Nadu was analyzed. Twelve sites with varying soil characteristics such as salinity, texture, and the host variety were chosen. Of the 402 strains isolated using NFB media, 302 were confirmed to be Azospirillum spp. and subjected to DNA polymorphism analysis using PCR-RFLP of 16S rDNA. They were also screened for their salt tolerance and microaerobic N2-fixing-dependent growth. On species identification, all the strains were found to be A. brasilense, A. lipoferum, or unidentified. On comparing the influence of the previously noted variability on the indigenous population, soil salinity was found to play a dominant role. This was revealed by PCR-RFLP studies and salt tolerance studies. A high association between soil salinity and the distribution of Azospirillum genotypes reveals that soil salinity should be taken into consideration while developing biofertilizers specifically for the coastal agricultural ecosystem.

Agriculture↗
PubMed2002

Grasses and gall midges: plant defense and insect adaptation.

The interactions of two economically important gall midge species, the rice gall midge and the Hessian fly, with their host plants, rice and wheat, respectively, are characterized by plant defense via R genes and insect adaptation via avr genes. The interaction of a third gall midge species, the orange wheat blossom midge, with wheat defense R genes has not yet exhibited insect adaptation. Because of the simple genetics underlying important aspects of these gall midge-grass interactions, a unique opportunity exists for integrating plant and insect molecular genetics with coevolutionary ecology. We present an overview of some genetic, physiological, behavioral, and ecological studies that will contribute to this integration and point to areas in need of study.

Adaptation, Physiological↗
PubMed2002

Diversity of Pseudomonas spp. isolated from rice rhizosphere populations grown along a salinity gradient.

Along the coastline of Tamil Nadu, five sites were chosen to assess the diversity of Pseudomonas populations isolated from rice (Oryza sativa) cultivated along a salinity gradient. One of these sites was under organic farming while the other four were under inorganic farming. A total of 256 Pseudomonas strains isolated from these five sites were analyzed using both phenotypic (substrate utilization patterns and antibiotic resistance assay) and genotypic (PCR-RFLP of 16S rDNA) characteristics. The results derived from this study indicate that soil salinity affects rhizosphere Pseudomonas populations. It was observed that increasing salinity led to decreasing diversity. Fluorescent pseudomonads were the dominant species found in the non-saline site, while in the saline sites they were replaced by salt-tolerant species, in particular Pseudomonas alcaligenes and P. pseudoalcaligenes. An interesting observation was the increase in diversity found in the saline site under organic farming. Organic farming was found to be capable of mitigating the harmful effects of saline stress to a large extent, and restoring the Pseudomonas diversity, thereby making it comparable with the diversity encountered in the non-saline site.

Adaptation, Physiological↗
PubMed2002

Multi-slice 3D-CTA - an improvement over single slice helical CTA for cerebral aneurysms.

BACKGROUND AND OBJECTIVE: The aim of this study was to demonstrate the utility of volume rendered multi-slice helical three-dimensional CT angiography in patients with cerebral aneurysm when compared with single slice CT angiography and formal digital subtraction angiography. METHODS: A prototype Toshiba Aquilon multi-slice CT scanner was employed with the following scan conditions: voltage 135 kV; current 300 mA; slice thickness 0.8 mm; scan speed 0.75 sec/cycle; couch speed 1 mm/sec; range 50 mm from foramen magnum; scan pitch 3; three dimensional images were reconstructed using multiple image projections and integral volume rendering algorithms on a Xlink/Xtension workstation. 80 cases of multi-slice CTA for cerebral aneurysm carried out at Fujita University from January 1999 to January 2001 were reviewed. RESULTS: The advantages of multi-slice imaging are illustrated with representative cases of cerebral aneurysm - good demonstration of three dimensional anatomy, appreciation of perforators down to 1 mm in size, delineation of the vessels around the aneurysm complex, relationship between the aneurysm and skull base, information on calcification, thrombus and blebs in the wall and eleven routine views for perusal. CONCLUSION: Multi-slice CTA is a significant improvement over single slice CTA for cerebral aneurysms. It is our experience the superior and precise images produced by multi-slice technology displays anatomical information not readily available from standard DSA. Multislice 3D-CTA is relatively non-invasive and provides better and adequate detail for surgical planning. The basis of multi-slice CT angiography is described. Multi slice CTA is changing the way cerebral aneurysms are being managed nowadays. New advances in the technology of multi-slice CTA resulting in increased image resolution are outlined.

Angiography, Digital Subtraction↗