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Biomedical subjects

A M Singh

Publications and source records attributed to A M Singh.

8 recordsLinked to original sources

Asthma exacerbations. 2: aetiology.

The natural history of asthma involves relatively stable periods that are often punctuated by significant exacerbations of symptoms. There are many aetiologies that may lead to an increase in asthma severity including respiratory infection (bacterial/viral), allergens, irritants, and occupational exposures. Each trigger probably acts through different mechanisms, but a final common pathway of multicellular inflammation, enhanced bronchial responsiveness, and airflow obstruction is a likely consequence. This review discusses the most common causes of asthma exacerbations with a focus on their microbiology and immunopathogenesis. Through an understanding of underlying causes of asthma exacerbations, treatments with increased effectiveness may be developed, and it is these future developments that may directly influence the morbidity and mortality of the disease.

Asthma↗

Fine needle aspiration cytology of liver: a study of 202 cases.

From January 1990 to December 2000, 202 patients with clinical evidence of liver disease underwent fine needle aspiration cytology of the liver. Of these, 102 patients were diagnosed as non-neoplastic lesions. These include diffuse parenchymal disease of liver, liver abscess, hepatitis, and granulomas. There were 100 patients with malignancies of the liver. Out of the above, 64 were due to metastatic carcinoma, 31 were primary hepatocellular carcinoma, 1 hepatoblastoma and in 4 patients the diagnosis of non-Hodgkin's lymphoma was made. By comparing with clinical and biochemical parameters, the diagnostic accuracy of the fine needle aspiration cytology, in this study, was found to be more accurate in malignant nodules of the liver as compared to other pathological lesion. The findings of fine needle aspiration cytology of the liver reported by other authors are discussed and it is concluded that this diagnostic method is a safe, useful and economic procedure with minimum complication and can be routinely done for assisting diagnosis of liver diseases in our clinical set up.

Adolescent↗

Influence of calcium, magnesium, or potassium ions on the formation and stability of emulsions prepared using highly hydrolyzed whey proteins.

Oil-in-water emulsions (4 wt % soy oil) containing 4 wt % whey protein hydrolysate (WPH) (27% degree of hydrolysis) and different levels of calcium, magnesium, or potassium chloride were prepared in a two-stage homogenizer. Other emulsions containing 4 wt % WPH but including 0.35 wt % hydroxylated lecithin and different levels of the above minerals were similarly prepared. The formation and stability of these emulsions were determined by measuring oil droplet size distributions using laser light scattering and by confocal scanning laser microscopy and a gravity creaming test. Both lecithin-free and lecithin-containing emulsions showed no change in droplet size distributions with increasing concentration of potassium in the range 0-37.5 mM. In contrast, the diameter of emulsion droplets increased with increasing calcium or magnesium concentration >12.5 mM. Emulsions containing hydroxylated lecithin were more sensitive to the addition of calcium or magnesium than the lecithin-free emulsions. Storage of emulsions at 20 degrees C for 24 h further increased the diameter of droplets and resulted in extensive creaming in emulsions containing >25 mM calcium or magnesium. It appears that both flocculation and coalescence processes were involved in the destabilization of emulsions induced by the addition of divalent cations.

Calcium↗

A simple microassay for computing the hemolytic potency of drugs.

A simple microassay and computer program are described for determining the erythrocyte hemolytic potency of drugs in vitro. This microassay is sensitive for both micro as well as macro ranges of hemoglobin concentration. An ELISA reader has been adapted to read erythrocyte lysis (hemolysis), which reduces the number and culture of replicates. A computer program was developed that calculates parameters such as C50 (concentration of drug causing 50% hemolysis), C100 (concentration of drug causing 100% hemolysis) and beta (slope of the curve) and graphically expresses the hemolytic patterns of various drugs simultaneously. The program can obtain optical densities directly from a 96-well plate ELISA reader by interfacing the microplate reader to the computer or by using a keyboard. This method is useful for screening a large number of hemolytic drugs and requires lower amounts of test compounds. It may also be applicable to quantitative functional assays, such as complement-mediated hemolysis and enumeration of antibody-secreting cells. The program can be obtained from the authors on request.

Animals↗

Anterior mandibulotomy for oral and oropharyngeal tumours.

In the last six years, anterior mandibulotomy was used to approach tumours of the oropharynx and oral cavity in 39 cases. Twenty-six of these had primary lesions in the anterior two-thirds of the tongue. Eight cases had lesions in the base tongue, three in the cheek, and two in the tonsil. Twenty-six cases had T3 tumours, nine had T2 lesions, and four had T4 tumours. Twenty-five patients received post-operative radiotherapy. In 16 cases the mandibulotomy was combined with a marginal mandibulectomy. In 23 cases reconstruction was carried out using a pectoralis major myocutaneous flap. Adequate margins on histopathology obtained in all but eight patients. Bone-related complications occurred in only three patients, all of whom were previously irradiated. Thus the anterior mandibulotomy provides excellent exposure for oral and oropharyngeal tumours, with low complication rate, and avoidance of segmental mandibulectomy.

Combined Modality Therapy↗

Use of specific polyclonal antibodies for site specific drug targeting to malaria infected erythrocytes in vivo.

The possibility of using specific polyclonal antibodies for effective site specific drug targeting to malaria infected erythrocytes has been examined. For this purpose, rabbit polyclonal antiserum was raised against Plasmodium berghei infected mouse erythrocytes (IRBC) and extensively absorbed with normal erythrocytes (NRBC). Absorbed antiserum specifically recognized IRBC. F(ab')2-fragments of these antibodies were coupled to chloroquine (chq) laden liposomes. These immunoliposomes when tested in vivo significantly suppressed malarial infection in mice.

Animals↗

The impact of migration on women and the family: research, policy and programme issues in developing countries.

"In the context of the pervasive invisibility of migrant women in the standard data collection, policy-making and planning processes, this paper seeks to review some of the major trends and patterns of female migration in developing countries; identify some important research priorities, and to delineate some of the areas in which policies and programmes might be framed so as to assist or change the impact of migration on women and the family. In the discussion of the relevance of these issues to national services and community organisation are emphasised as priority action programmes."

Demography↗