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Biomedical subjects

A Balachandran

Publications and source records attributed to A Balachandran.

15 recordsLinked to original sources
PubMed2002

Failure to demonstrate involvement of antibodies to Acinetobacter calcoaceticus in transmissible spongiform encephalopathies of animals.

Acinetobacter calcoaceticus, a soil microbe, contains molecular sequences which resemble those found in neurofilaments of the brain tissue. It was hypothesized that if cattle ingest large amounts of feedstuff containing A. calcoaceticus, they may develop an autoimmune reaction, with consequences of pathological changes associated with transmissible spongiform encephalopathies (TSEs). The hypothesis was tested using a small number of serum samples collected from cattle and it was found that affected individuals had elevated serum antibody levels to this organism. If this finding was substantiated, it would provide a possible means of diagnosing TSEs in vivo. In the present communication, a larger number of cattle, elk and sheep with or without TSEs were tested using A. calcoaceticus whole cell and lipopolysaccharide antigens as well as myelin basic protein (MBP). It was found that antibody levels in normal and affected animals overlapped considerably, thus casting doubt on the usefulness of these antigens as diagnostic tools for TSEs and on the hypothesis of A. calcoaceticus being a cause of TSEs.

Acinetobacter calcoaceticus↗
PubMed2002

Validation of monoclonal antibody F99/97.6.1 for immunohistochemical staining of brain and tonsil in mule deer (Odocoileus hemionus) with chronic wasting disease.

A new monoclonal antibody (MAb), F99/97.6.1, that has been used to demonstrate scrapie-associated prion protein PrP(Sc) in brain and lymphoid tissues of domestic sheep with scrapie was used in an immunohistochemistry assay for diagnosis of chronic wasting disease (CWD) in mule deer (Odocoileus hemionus). The MAb F99/97.6.1 immunohistochemistry assay was evaluated in brain and tonsil tissue from 100 mule deer that had spongiform encephalopathy compatible with CWD and from 1,050 mule deer outside the CWD-endemic area. This MAb demonstrated abnormal protease-resistant prion protein (PrP(res)) in brains of all of the 100 mule deer and in 99 of the 100 tonsil samples. No immunostaining was seen in samples collected from deer outside the endemic area. MAb F99/97.6.1 demonstrated excellent properties for detection of PrP(res) in fresh, frozen, or mildly to moderately autolytic samples of brain and tonsil. This immunohistochemistry assay is a sensitive, specific, readily standardized diagnostic test for CWD in deer.

Animals↗
PubMed2001

Drug therapy of childhood asthma.

Drug therapy is used to prevent and control asthma, and also to reduce the frequency and severity of its exacerbations, and reverse airflow obstruction. Asthma medications are thus categorized into two general classes--bronchodilators (relievers) and anti-inflammatory drugs (preventers). Short acting beta2-agonists is the therapy of choice for relief of acute symptoms and prevention of exercise induced bronchospasm (EIB). Corticosteroids are the most potent and effective anti-inflammatory medication currently available. Inhaled form is used in the long-term control of asthma. Systemic corticosteroids are used to gain prompt control of the disease when initiating long-term therapy. Long acting bronchodilator used concomitantly with anti-inflammatory medications for long-term control of symptoms, especially nocturnal symptoms. Ipratropium bromide may provide some additive benefit to inhaled beta2-agonists in severe exacerbations. Sustained release theophylline is a mild to moderate bronchodilator used principally as adjuvant to inhaled corticosteroids for prevention of nocturnal asthma. Leukotriene modifiers may be considered as an alternative therapy to inhaled corticosteroids or cromolyn or nedocromil.

Adrenergic beta-Agonists↗
PubMed1995

Flexible fibreoptic bronchoscopy in 582 children--value of route, sedation and local anesthetic.

The value of route, sedation and local anesthetic was studied in 582 children aged 50 days to 12 years who were subjected to flexible fibreoptic bronchoscopy (FFBS) at the Institutes of Child Health, Madras, during January 1989 to July 1993. Pentax 3.5 mm and Olympus 4.9 mm bronchoscopes were used. Bronchoscopy was performed with sedation and/or local anesthetic through nasal/oral route after premedication with atropine. It was successfully carried out through nasal route in 97.4% and only in 40% through oral route. As nasal route proved advantageous, the oral route was abandoned.

Anesthesia, Local↗
PubMed1994

Experimental rabies infection of non-nervous tissues in skunks (Mephitis mephitis) and foxes (Vulpes vulpes).

Non-neural tissues, from three male and four female stripped skunks (Mephitis mephitis), 5 to 7 months old, and one male and two female red foxes (Vulpes vulpes), 12 to 16 months old, experimentally infected with street rabies virus, were examined by light microscopic immunohistochemical and electron microscopic methods. This is the first report of ultrastructural lesions in rabies-infected adrenal medulla, cornea, and nasal glands. Using the streptavidin biotin peroxidase technique, antigen was detected in mucous cells and interstitial neurons and their processes in the submandibular salivary gland, in chromaffin cells of the adrenal medulla, in epidermal cells of the skin, in external root sheath cells of hair follicles, and in corneal epithelial cells. Electron microscopically, matrix (viral nucleocapsid), virions, and anomalous viral products were common in most tissues examined, but their relative proportions varied. The results suggested that replication with minimal accumulation of matrix and anomalous viral growth products was characteristic of growth in tissues (submandibular salivary gland) that frequently produce high titers of virus, whereas replication with large amounts of matrix and anomalous structures occurred in tissues (adrenal gland and nasal gland) that generally contained low or moderate titers of virus. Novel findings included viral budding into secretory granules, increase in microfilaments in infected mucogenic cells, and continuity of viral convoluted membranous profiles with rough endoplasmic reticulum of chromaffin cells and nasal glandular cells. The presence of viral antigen and developing virus in extra-neural tissues constitutes a potential risk of non-bite exposure to people in certain groups/occupations.

Adrenal Glands↗
PubMed1994

Tuberculous disease in a pediatric referral centre: 16 years experience.

Children with evidence of tuberculous disease registered at the TB Clinic, Institute of Child Health, Madras during the years 1977 to 1992 were analyzed. Progressive primary complex, is the commonest thoracic form of tuberculosis while tuberculous meningitis is the commonest extra thoracic form. The overall prevalence of various clinical forms of tuberculosis has decreased over the last 16 years. There is an increasing trend in the prevalence of progressive primary complex among the BCG vaccinated group. The prevalence of pleural effusion, bone tuberculosis and abdominal tuberculosis is almost same over the last 16 years and is more in the BCG non vaccinated children. In tuberculous adenitis there is no significant variation between the two groups. The occurrence of tuberculous meningitis is in the ratio of 1:3 among BCG vaccinated and non-BCG vaccinated children. Though the prevalence of miliary tuberculosis is negligible, it is significantly more in BCG non-vaccinated children. There is a tendency for slight decrease in overall mortality due to tuberculosis in the last 10 years but the mortality due to tuberculous meningitis continues to be the same over the past 16 years.

Abdomen↗
PubMed1994

Pulmonary cavitatory tuberculosis in children.

This study was undertaken to analyse children with pulmonary cavitatory tuberculosis which is a rare and infectious condition. The pretreatment characteristics, course and response to three different anti-tuberculous regimes in 27 children with cavitary pulmonary lesions registered at the TB Clinic, Institute of Child Health, are described. Male:Female ratio was 1.2:4. Thirty per cent of affected children were below 3 years of age and had predominant lower lobe involvement whereas in older children the upper lobes were affected. Eighty five per cent of children had definite history of contact with an adult with tuberculosis. Tuberculin test was positive in 70% of children. Cavitary lesion were observed in the right lung in 66% of cases. Follow up and surveillance was carried out in 23 children who completed the anti tuberculous treatment. Regimes with isoniazid, rifampicin, pyrazinamide and streptomycin were given to different groups. Response and compliance was also monitored. Eleven out of 23 children had persistence of radiological lesions even after completion of 9 months of therapy. Inclusion of streptomycin with 2 or 3 bactericidal drugs in the intensive phase showed a better response.

Child↗
PubMed1985

Scanning and transmission electron microscopic studies on the oviducts of Pekin ducks fed methyl mercury containing diets.

This study was undertaken to examine the effects of varying levels of methyl mercury (MeHg) on the ultrastructure of the surface epithelium of the oviduct of ducks. Accordingly, Pekin ducks were maintained on feed containing varying doses of (0.0; 0.5; 5.0; 15.0 ppm) of MeHg (Group I - control to IV) for 12 weeks and sacrificed. Tissue from the magnum and the shell gland regions of the oviduct was processed for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the primary and secondary folds of these regions of the oviducts of the control and 0.5 ppm treatment group were densely populated with ciliated cells and that the cilia tend to cover the apical surfaces of the non-ciliated secretory cells. This unchanged ultrastructural morphology of the surface epithelium of 0.5 ppm treatment group was verified with TEM. The ciliated and nonciliated cells in surface epithelium appeared to be equal in frequency. The nuclei of ciliated cells were superficial in location compared to nonciliated secretory cells which had nuclei in the basal part of the cytoplasm. In the oviductal tissues from ducks fed 5.0 ppm MeHg isolated areas of ciliary loss, but minimal disruption of the apical plasma membrane were observed by SEM. In a few birds plasma membrane lesions, condensation of nuclear chromatin and very dilated rough endoplasmic reticulum were seen with TEM. In the oviductal tissues from ducks fed 15.0 ppm MeHg it could be seen that ciliary loss was much more extensive than hitherto observed, and disruption of the apex of cells could be seen. TEM showed degeneration of cytoplasmic organelles, more or less severely damaged ciliated cells, loss of ciliary extensions and formation of compound cilia. These observations indicate that methyl mercury at 5.0 and 15.0 ppm dose levels causes toxic injury to oviductal surface epithelium of Pekin duck that may cause reduced reproductive capability.

Animals↗
PubMedDate not supplied

Childhood asthma--advances in pathogenesis.

Increase in morbidity and mortality of asthmatics in the world is a cause of concern. Many researchers have described various aspects of etiopathogenesis which has thrown light on the better understanding of asthma. Our experience with nearly 3 lakhs of asthmatic children, over a period of twenty-five years and our studies in Asthma clinic of ICH & HC, Madras generated new ideas to propose a hypothesis on etiopathogenesis of asthma. "Asthma is a disease caused by a specific infective agent in a genetically predisposed individual resulting in altered cellular response initially leading to hyperactive bronchial tree which on exposure to various aggravating factors manifest clinically as recurrent cough, dyspnoea and wheeze". Category of wheezers who manifest asthma is also discussed.

Administration, Inhalation↗
PubMedDate not supplied

Flexible fiberoptic bronchoscopy.

The value of flexible fiberoptic bronchoscopy in children are increasing day by day, but still underutilized even in many advanced institutions. 630 Fiberoptic bronchoscopy procedures under local anaesthesia were performed for various clinical conditions for diagnosis and therapy. Nasal route is preferred than oral route. Therapeutic indications are more in children than adults. Nearly one third of children with collapse, consolidation have shown radiological clearance after repeated bronchoscopy.

Adolescent↗