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Biomedical subjects

R Vijayaraghavan

Publications and source records attributed to R Vijayaraghavan.

At least 55 records · Page 3Linked to original sources
PubMed1995

Combined therapeutic potential of meso-2,3-dimercaptosuccinic acid and calcium disodium edetate on the mobilization and distribution of lead in experimental lead intoxication in rats.

Asymptomatic lead poisoning remains a serious public health problem in developed and developing countries. Chelation therapy particularly with calcium disodium ethelenediamine tetracetic acid (CaNa2EDTA) is often used therapeutically to reduce the body burden of lead. This chelating drug has serious side effects and drawbacks primarily related to redistribution of lead, nephrotoxicity, and essential metal depletion. The present study was planned to determine the effectiveness of CaNa2EDTA and meso-2,3-dimercaptosuccinic acid (DMSA) used in combination. Both drugs, when administered individually, resulted in significant urinary excretion of lead and lowered the tissue lead burden. Combined treatment with CaNa2EDTA and DMSA elicits an additive response in promoting urinary lead elimination, depleting body lead burden, and restoring altered lead-sensitive biochemical variables. Further, no redistribution of lead to brain or any other soft organ following combined DMSA-CaNa2EDTA treatment was observed indicating a definite advantage of combined therapy over the conventional treatment with CaNa2EDTA or DMSA alone. However, an elevation of serum transaminase activity, creatinine level, and depletion of blood zinc level may limit the usefulness of this combined treatment.

Alkaline Phosphatase↗
PubMed1995

Effect of inhaled aerosol of 1-chloroacetophenone (CN) and Dibenz (b,f)-1,4 oxazepine (CR) on lung mechanics and pulmonary surfactants in rats.

Inhalation toxicity following exposure to 1-Chloroacetophenone (CN) and Dibenz(b,f)-1,4 oxazepine (CR) aerosols for 60 min at sublethal concentrations were studied in rats. The dynamic surface tension (gamma max and stability ratio) of lung homogenate increased significantly on CN exposure. The lung mechanics studies revealed a significant increase in compliance in CN exposed rats. CR, on the other hand did not influence any of the above variables except for a decrease in compliance. Total lung phospholipids and sphingomyelin contents decreased significantly following exposure to CN, while CR exposure produced an increase in sphingomyelin, reduction in phosphatidylcholine and ethanolamine, with no change in total phospholipid contents. Histomorphological observations indicated cellular degeneration in the epithelium of the bronchiole and alveolar septal-wall thickening due to the presence of an increased number of mononuclear cells in CN exposed rats. However, CR induced inflammatory reaction and enlargement of respiratory air spaces. It is concluded that of the two sensory irritants (tear gases) examined, CN is potentially more toxic compared to CR in rats.

Administration, Inhalation↗
PubMed1994

Computer assisted recognition and quantitation of the effects of airborne chemicals acting at different areas of the respiratory tract in mice.

The pattern and timing of a normal breath in unanesthetized mice was analyzed from measurement of inspiratory and expiratory airflows (VI and VE). Airflow was measured via a differential pressure transducer, attached to a pneumotachograph, which itself was attached to a body plethysmograph into which a mouse was placed. The analog voltage from the differential pressure transducer was digitized and stored for analysis on a microcomputer. Criteria were developed to classify each breath as normal (N) or belonging into one of seven abnormal categories. The abnormal categories were arrived at by computer analysis, recognizing specific modifications of the normal pattern into patterns of: sensory irritation of the upper respiratory tract (S), airflow limitation within the conducting airways of the lungs (A) or pulmonary irritation at the alveolar level (P). Combinations of these effects, i.e., S+A, P+A, P+S and P+S+A were also recognized. Computer analysis of each breath also permitted quantitative evaluation of the degree of S, A or P abnormalities. To induce each type of effect we used inhalation exposures to 2-chlorobenzylchloride, carbamylcholine or propranolol. We propose that this approach will permit rapid evaluation of the possible effects of airborne chemicals at three levels of the respiratory tract, with the classification of the type of effect easily obtained in an objective way using well defined criteria, followed by quantitation of the degree of each effect.

Administration, Inhalation↗
PubMed1994

Dose dependent effects on lymphoid organs following a single dermal application of sulphur mustard in mice.

The effects of a single dermal application of sublethal doses [15.5, 7.75 and 3.88 mg kg-1] of bis(2-chloroethyl)sulphide [sulphur mustard, SM] on body weight, organ/body weight ratio, haematology, histology and cellularity of spleen and thymus were studied after 7 days, in Balb/c mice. A progressive fall in body weight was noticed from the fifth day onwards after SM treatment. A dose-dependent decrease in the relative weights of spleen, liver and peripheral lymph nodes, and an increase in adrenal weight were also seen. An increase in red blood cell count, packed cell volume and haemoglobin concentration following SM intoxication were also dose dependent. These changes, together with a significant reduction in the cellularity of the spleen and thymus and degenerative histological changes, show that a single sublethal dermal dose of SM can cause considerable dose dependent systemic effects in Balb/c mice.

Administration, Cutaneous↗