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Biomedical subjects

V Kannan

Publications and source records attributed to V Kannan.

At least 19 recordsLinked to original sources
PubMed2006

A comparative study of body potassium content in males and females at Kalpakkam (India).

A group of 300 subjects of both sexes were measured for total body potassium content using a shadow shield whole-body counting system at Kalpakkam (India). The mean body potassium content for males was 1.7 +/- 0.5 g kg(-1) body weight and 1.5 +/- 0.5 g kg(-1) body weight for females. The body potassium content varies inversely with age as well as with the body weight for both the sexes. However, the total body potassium varies directly with body-build index for both males and females. The mean annual dose due to (40)K for males and females was found to be 149 +/- 44 and 132 +/- 41 uGy, respectively.

Adolescent↗
PubMed2005

Antihepatotoxic effect of beta-carotene on paracetamol induced hepatic damage in rats.

Enzyme levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and alkaline phosphatase (ALP) increased following paracetamol induction were significantly lowered due to pretreatment with the beta-carotene (BC). This supplementation reversed the trend inducing a significant decrease in bilirubin and urea levels. Paracetamol administration significantly reduced hepatic glycogen, glutathione (GSH), glutathione-S-transferase (GST), glutathione peroxidase (GPX) and glutathione reductase (GSH-R). Pretreatment of rats with BC significantly increased the enzyme activities. The results suggest hepatoprotective activity of BC.

Acetaminophen↗
PubMed2005

Asymptomatic typhoid carriers in Namakkal District, Tamilnadu.

A study was made on the sources and spread of Salmonella spp at Namakkal District, Tamilnadu, to ascertain positive carriers of the pathogen. Of the 150 samples collected from varied sources, food handlers significantly contributed to the spread of S. typhi, S. paratyphi A and B, the presence of which was ascertained by standard confirmatory tests. It is inferred that a periodic assay of Salmonella spp in food stuff and food handlers can help in the control of food borne disease.

Carrier State↗
PubMed2005

Study on ground water characteristics and the effects of discharged effluents from textile units at Karur District.

A study was made on the physico-chemical characteristics of water samples mixed with effluent discharged from textile industries at Chellandipalayam (Site--I), Senaparatti (Site--II) and Pasupathipalayam (Sites--III and IV) revealed the elevated levels of Ca, Mg, Na, Cr, K, Ni, Cu, Zn, CO3, SO4, NO3 and Cl- . The concentrations of these ions exceeded the limit prescribed by ISI. The increase in the concentrations of ions was revealed by higher values of electrical conductivity (EC). Water at these sites was found to be hard, brackish and unsuitable for drinking purpose. In all these sites, the seed germination of rice alone was significantly affected among the other crops tested. Irrigation of crops with ground water notably lowered the quantity of reserve food in rice, wheat (starch), and sugarcane (sugar), indicating the interference of their metabolic pathway by polluted ground water.

Carbohydrates↗
PubMed2004

First diastereoselective intramolecular Baylis-Hillman reaction: an easy access to chiral alpha-methylene-beta-hydroxylactones.

The first diastereoselective intramolecular Baylis-Hillman reaction of chiral substrates is reported wherein both aldehyde and activated olefin coexist as substituents to afford alpha-methylene-beta-hydroxylactones in good yields exclusively as single isomers under the standard base-catalyzed reaction conditions in CH(2)Cl(2). Formation of alkoxylactones by an in situ derivatization of adducts was also observed.

Journal Article↗
PubMed2002

Direct calibration of a reference standard against the air kerma strength primary standard, at 192Ir HDR energy.

The primary standard of low air kerma rate sources or beams, maintained at the Radiological Standards Laboratory (RSL) of the Bhabha Atomic Research Centre (BARC), is a 60 cm3 spherical graphite ionization chamber. A 192Ir HDR source was standardized at the hospital site in units of air kerma strength (AKS) using this primary standard. A 400 cm3 bakelite chamber, functioning as a reference standard at the RSL for a long period, at low air kerma rates (compared to external beam dose rates), was calibrated against the primary standard. It was seen that the primary standard and the reference standard, both being of low Z, showed roughly the same scatter response and yielded the same calibration factor for the 400 cm3 reference chamber, with or without room scatter. However, any likelihood of change in the reference chamber calibration factor would necessitate the re-transport of the primary standard to the hospital site for re-calibration. Frequent transport of the primary standard can affect the long-term stability of the primary standard, due to its movement or other extraneous causes. The calibration of the reference standard against the primary standard at the RSL, for an industrial type 192Ir source maintained at the laboratory, showed excellent agreement with the hospital calibration, making it possible to check the reference chamber calibration at RSL itself. Further calibration procedures have been developed to offer traceable calibration of the hospital well ionization chambers.

Air↗
PubMed2002

Distribution of natural and anthropogenic radionuclides in soil and beach sand samples of Kalpakkam (India) using hyper pure germanium (HPGe) gamma ray spectrometry.

Pre-operational survey at Kalpakkam coast, indicated elevated gamma background radiation levels in the range of 100-4000 nGy h(-1) over the large tracts of the coastal sands due to the presence of pockets of monazite mineral in beach sands. In view of the prevalence of monazite, a systematic gamma spectrometric study of distribution of natural radionuclides in soil and beach sand samples collected from the terrestrial and coastal environment of Kalpakkam was performed and concentrations of primordial radionuclides such as 238U, 232Th and 40K and anthropogenic radionuclide 137Cs were determined. The concentrations of 238U, 232Th and 40K in soil samples were 5-71, 15-776 and 200-854 Bq kg(-1) dry, respectively. In beach sand samples, 238U, 232Th and 40K contents varied in the range of 36-258, 352-3872 and 324-405 Bq kg(-1) dry, respectively. The total absorbed gamma dose rate in air due to the presence of 238U, 232Th and 40K in Kalpakkam soil samples varied between 24 and 556 nGy h(-1) with a mean of 103 nGy h(-1). The contribution to the total absorbed gamma dose rate in air in the decreasing order was due to the presence of 232Th (76.4%), followed by 40K (16.9%) and 238U (6.7%) in Kalpakkam soils. However, in beach areas of Kalpakkam, the presence of 232Th in beach sand contributed maximum (94.0%) to the total absorbed gamma dose rate in air followed by 238U (4.7%) and minimum contribution was by 40K (1.3%). 137Cs in Kalpakkam soils ranged from < or = 1.0 to 2.8 Bq kg(-1) dry, which was 1-3 order of magnitude less than the concentration of primordial radionuclides in soil.

Cesium Radioisotopes↗
PubMed2002

A novel strategy of oxygen restriction by some diazotrophic enteric bacteria.

Protection of nitrogenase against oxygen inactivation in diazotrophs involves numerous strategies. Glutathione is known to play an important role in scavenging oxyradicals in many living systems. The involvement of glutathione (reduced) (GSH), glutathione peroxidase (GPX) and glutathione reductase (GR) in the protection of nitrogenase in free living diazotrophs is reported here for the first time. Reduced glutathione content and the activity of glutathione peroxidase and glutathione reductase increased with increase in oxygen concentration under nitrogen fixing conditions but decreased under anaerobic and nitrogenase repressed conditions. This correlation is used to postulate a protecting role for GSH-GPX-GR system against oxygen inactivation of nitrogenase.

Enterobacteriaceae↗
PubMed2002

Reversibility of oxygen induced inactivation of nitrogenase in some enterobacteria.

Aerobic and microaerobic diazotrophs possess numerous oxygen restriction strategies to protect nitrogenase from inactivation by oxygen without interfering with energy generation through oxidative phosphorylation. Protection by conformational change in nitrogenase was first detected and described in Azotobacter. This strategy once considerd unique for Azotobacter has been shown in this study to occur in Citrobacterfreundii (Braak) Werkman and Gillen and Klebsiella pneumoniae subspecies rhinoscleromatis (Trevisan) Migula also. However, in these enteric bacteria the entire enzyme is not protected probably due to the absence of any respiratory protection similar to that found in the aerobe, Azotobacter.

Enterobacteriaceae↗
PubMed2001

Dose estimates to the public from 210Po ingestion via dietary sources at Kalpakkam (India).

Distribution of one of the natural radionuclides 210Po activity in food of plant origin such as cereals, pulses, vegetables and food of animal origin such fish, crab, prawn, chicken, egg etc. were determined in and around Kalpakkam upto a distance of 32 km radius. The general range of 210Po activity levels in all the dietary components (excluding milk and drinking water which are reported in mBq l(-1)) ranged widely from < or = 10 to 122,641 mBq kg(-1) fresh, the minimum being in vegetables and maximum being in the edible portions (muscle) of crab samples. 210Po levels in drinking water and milk samples ranged between 0.6-2.6 and 8-12 mBq l(-1) respectively. 210Po content in cereals ranged from < or = 32 to 745 mBq kg(-1) and in pulses it was found to vary between < or =32 and 294 mBq kg(-1). The range of 210Po activity in different types of vegetables was found to be < or = 10-653 mBq kg(-1). Among the different varieties of vegetables, 210Po was significantly higher in leafy vegetables (28-653 mBq kg(-1)) as compared to rooty and other types of vegetables which ranged from < or = 10-180 mBq kg(-1). In food of animal origin, the observed minimum activity of 210Po was 8 mBq l(-1) in milk and the maximum observed was 122,641 mBq kg(-1) in the muscles of crab. It was also observed that 210Po activity was found to be in higher levels in the food of aquatic animal origin (1414-122,641 mBq kg(-1)) than in the food of terrestrial animal origin (other than milk) which varied from 41 to 963 mBq kg(-1). It is evident from the present study that the foods of animal origin especially crab, fish and prawn deliver significantly greater dose (93-3364 microSv yr(-1)) to the public compared to foods of plant origin whose mean dose ranged 0.08-128 microSv yr(-1). The study showed evidence to suggest that the total ingestion dose due to 210Po received by the Kalpakkam public through dietary sources is significantly higher than the ingestion dose received due to fallout sources such as 137Cs and 90Sr.

Animals↗
PubMed1999

Gamma-knife radiosurgery for trigeminal neuralgia.

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70-80 Gy was delivered to the trigeminal root entry zone, 2-4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5-16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.

Adult↗
PubMed1998

Fine-needle aspiration of metastatic renal-cell carcinoma masquerading as primary breast carcinoma.

This report details a fine-needle aspiration biopsy performed in the investigation of two right breast nodules in a patient with previous history of lumpectomy for infiltrating ductal carcinoma in the same breast 3 years before. Because the cytology was atypical for a mammary carcinoma and cells did not match the morphology of the previous breast carcinoma, a tissue biopsy was recommended, revealing the presence of metastasis from a previously silent primary renal-cell carcinoma. This report illustrates not only how metastatic lesions in the breast can masquerade clinically as a primary carcinoma but also the necessity for the cautious approach to interpreting the fine-needle aspiration biopsy of these lesions. Furthermore, essential guidelines necessary to distinguish primary from metastatic lesions in the breast are presented.

Aged↗
PubMed1998

Sacral chordomas: a 10-year study.

A retrospective analysis of 14 cases of sacral chordoma seen between 1984 and 1993 at the Kidwai Memorial Institute of Oncology is reported. The mean patient age was 54 years, with 13 males and one female. Seventy-one per cent of patients presented with symptoms related to a painful sacral mass. Eight patients underwent radical surgery and two had adjuvant radiotherapy. One patient had a partial tumour resection. Three patients received radical radiotherapy. Two patients were offered only pain relief medication. The median follow-up was 33 months. The actuarial overall survival (OS) at 5 years was 48%. In the 12 patients in whom curative therapy was attempted, the 5-year OS was 56% and progression-free survival was 36%. Four patients developed local recurrence and three developed distant metastasis.

Chordoma↗
PubMed1998

Role of electron beam treatment in postoperative management of carcinoma of the breast.

The aim of post operative radiotherapy to chest wall and drainage areas in advanced breast cancer is to sterilize the possible microscopic disease. Fifty cases of post surgical breast cancers were evaluated in a prospective study of chest wall radiation therapy by electrons. Fifty women of histologically proved post operative invasive breast cancers underwent simple mastectomy with axillary dissection followed by post-operative radiotherapy (Electron) to chest wall +/- drainage area. The chest wall and IMC was treated by a direct electron beam (9/12 MeV and 12 MeV) at fixed angle. 6 MV X-ray beam was used to treat axillary apex and supraclavicular area. In some cases, supplement RT was given by 6 MV X-rays through small posterior axillary portal. The energy of electron beam was 9 MeV or 12 MeV depending on the thickness of treated area. The supraclavicular and axillary lymphatic regions were treated, by direct custom shaped anterior portal. The dose delivered was 50 Gy over 5 weeks at 2 Gy per fraction. Adjuvant chemotherapy was given to patients who were pre-menopausal with histologically proved axillary node involvement as Cyclophosphamide, Methotrexate and 5-Fluorouracil (CMF) after radiotherapy. Post menopausal patients received adjuvant tamoxifen 10 mg.bid. The overall time varied from 26 to 87 days with a median of 41.5 days (SD 11.7). The followup period varied from 4-32 months with a mean of 22 months (SD 6.4). All the fifty patients developed dense pigmentation towards the end of radiation therapy, along with patchy dry desquamation. Moist desquamation occurred in 6 patients. The median OTT in the patients who developed moist desquamation was 34.5 days. The moist reaction healed over 10-15 days after completion of radiotherapy. Lung Fibrosis (Apical lobe) occurred in four patients. The fibrosis was evident at a median of 12 months of follow up. Lymphoedema of the ipsilateral arm occurred in six patients. None of 50 patients developed late sequalae like Cardiac effects, Rib fracture, Brachial Plexopathy, Shoulder joint impairement and Soft tissue effects. Local control in this study was 96% (48 patients). The two year actuarial overall survival was 80%. In early stages survival was significantly better compared to late stages. The actuarial two year DFS was 72%. In early stages DFS was significantly better compared to late stages.

Adult↗
PubMed1997

Efficacy and safety of granulocyte macrophage-colony stimulating factor (GM-CSF) on the frequency and severity of radiation mucositis in patients with head and neck carcinoma.

PURPOSE: Based on the clinical evidence of mucosal protection by GM-CSF during cytotoxic chemotherapy, a pilot study was undertaken to determine the safety and mucosal reaction of patients receiving GM-CSF while undergoing definitive conventional fractionated radiotherapy in head and neck carcinoma. METHODS AND MATERIALS: Patients were considered eligible if buccal mucosa and oropharynx were included in the teleradiation field. Ten adult patients with squamous cell carcinoma of head and neck (buccal mucosa--8 and posterior 1/3 tongue--2) were entered into the trial. Radiation therapy was delivered with telecobalt machine at conventional 2 Gy fraction and 5 fractions/week. The radiation portals consisted of two parallel opposing lateral fields. GM-CSF was given subcutaneously at a dose of 1 microg/kg body weight, daily, after 20 Gy until the completion of radiation therapy. Patients were evaluated daily for mucosal reaction, pain, and functional impairment. RESULTS: The median radiation dose was 66 Gy. Eight patients received > or = 60 Gy. The tolerance to GM-CSF was good. All 10 patients completed the planned daily dose of GM-CSF without interruption. Mucosal toxicity was Grade I in four patients till the completion of radiotherapy (dose range 50-66 Gy). Six patients developed Grade II reaction, fibrinous mucosal lesions of maximum size 1.0-1.5 cm, during radiotherapy. None developed Grade III mucositis. The maximum mucosal pain was Grade I during GM-CSF therapy. In two patients after starting GM-CSF the pain reduced in intensity. Functional impairment was mild to moderate. All patients were able to maintain adequate oral intake during the treatment period. Total regression of mucosal reaction occured within 8 days following completion of radiotherapy. CONCLUSIONS: GM-CSF administration concurrently with conventional fractionated radiotherapy was feasible without significant toxicity. The acute side effects of radiotherapy namely mucositis, pain, and functional impairment were nil to minimal. The results are suggestive of mucosal protection by GM-CSF during radiotherapy and warrants further study in randomized double blind trial.

Adult↗
PubMed1997

Synovial sarcoma of the neck.

Primary synovial sarcoma of the head and neck region is a rare tumor. This report describes seven cases of primary synovial sarcomas, of which two were in the parapharyngeal region, two in the supraclavicular region, and one each in the hypopharynx, sternocleidomastoid and submandibular regions. Clinical presentations, radiological findings, histopathology and management are reviewed. All patients received multimodal therapy using aggressive surgery, radiotherapy and chemotherapy. Five of the patients are alive and disease free after 24-108 months of follow-up. Achievement of locoregional control appears to be the hallmark of successful therapy.

Adolescent↗