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Biomedical subjects

N Radhakrishnan

Publications and source records attributed to N Radhakrishnan.

17 recordsLinked to original sources

Antibacterial activity of two plant extracts on eight burn pathogens.

Antibacterial activity of crude alcoholic extract of Datura alba and Celosia argentea leaves were studied against pathogens isolated from infected burn patients. The disc-diffusion method showed significant zone of lysis against all the pathogens studied and the results are comparable to the conventional antibiotic cream namely Silver Sulphadiazine (SSD). On comparing the efficiency of the two extracts, extract of D. alba exhibited more than 50% increase in antibacterial activity compared to C. argentea.

Bacteria↗

Healing potential of Datura alba on burn wounds in albino rats.

Datura alba Nees (Solanaccae) is popular all over the world for its medicinal uses in asthma, muscle spasm, whooping cough, hemorrhoids, skin ulcers, etc. In India, it is widely used traditionally for the relief of rheumatism and other painful affections. Ayurveda and Siddha practitioners use oil based preparations of this plant from ancient days to till date for all types of wounds. Hence, the present study was chosen to evaluate its scientific validity. The alcohol extract of the D. alba leaves were investigated for the evaluation of its healing efficiency on burn wound models in rats. The crude alcohol extract and one of the fractions exhibited antimicrobial effect against all the pathogens studied. A 10% (w/w) formulation of alcoholic extract was topically applied on thermal wounds. Complete wound closure was observed within 12 days in treated rats. The effect produced by the ointment, in terms of wound contracting ability, wound closure time, tissue regeneration at the wound site and histopathological characteristics were significant in treated rats. Collagen, hexosamine and gelatinase expressions were also well correlative with the healing pattern observed. The present study thus provides a scientific rationale for the traditional use of this plant in the management of wounds.

Animals↗

Lymphopenia in dialysis patients: a preliminary study indicating a possible role of apoptosis.

Lymphopenia is a common finding in dialysis patients. Since infection rate and mortality associated with infection are high in dialysis patients, lymphopenia may be one of the contributing factors. In the present study, we evaluated the mechanism responsible for lymphopenia in these patients. Lymphocytes isolated from dialysis patients showed increased apoptosis (p < 0.001) when compared to lymphocytes isolated from healthy subjects (healthy subjects, 0.5 +/- 0.2% vs. dialysis patients, 8.8 +/- 0.7% apoptotic cells/field). Sera from dialysis patients promoted lymphocyte apoptosis in a time- and dose-dependent manner. These sera also enhanced lymphocyte DNA fragmentation into multiple integers of 180 base pairs in the form of a ladder pattern. Cellulose acetate membranes promoted T cell apoptosis when compared to polysulfone membranes and to control. Cellulose acetate dialysis membranes also appear to promote lymphocyte FasL expression. Similarly, dialysis sera enhanced T cell Fas as well as FasL expression. Neither the cellulose acetate nor polysulfone membranes could induce FasL expression on B cells. Similarly, dialysis sera failed to induce FasL expression on B cells. On the other hand, anti-FasL antibodies attenuated dialysis sera-induced apoptosis in T as well as B cells. Interestingly, dialysis serum showed a 5-fold increase in FasL content when compared with control serum. These results suggest that dialysis-associated factors can induce autocrine death in T cells but the help of activated T cells is required to induce death in B cells.

Adult↗

Iliac artery stenosis causing post-renal transplant hypertension: successful management by percutaneous angioplasty and stent implantation.

Atherosclerotic occlusion of the native iliac arteries and/or transplant renal artery is a major cause of post-transplant hypertension. Iliac artery stenosis mimics renovascular hypertension and may cause renal dysfunction in transplant recipients. We report a case of a 61-year-old renal transplant recipient with native bilateral iliac artery stenoses and coronary artery disease. He presented with severe hypertension and was managed successfully with angioplasty and stenting of native iliac arteries.

Angioplasty, Balloon↗

Morphine-induced degradation of the host defense barrier: role of macrophage injury.

The effect of morphine on the degradation of the host defense barrier in rats and mice was studied. Mice received either 3 or 11 doses of morphine. Mice receiving 11 doses of morphine showed gram-negative bacteremia and bacterial growth in samples of peritoneal fluid (PF), liver, spleen, kidneys, heart, and lungs; PF and tissue samples from only 1 control mouse showed bacterial growth, and no control mice had bacteremia. Mice receiving 11 doses also had suppressed bone marrow macrophage colony formation. Monocytes and peritoneal macrophages harvested from morphine-treated mice showed greater injury than did those from control mice. Pretreatment of mice with naloxone inhibited morphine-induced macrophage injury and degradation of the host defense barrier. In in vitro studies, morphine attenuated the killing of bacteria phagocytosed by macrophages and also facilitated their escape. This study indicates that morphine-induced monocyte and macrophage injury may be linked to degradation of the host defense barrier.

Analgesics, Opioid↗

Percutaneous transvenous mitral commissurotomy in a patient with prosthetic aortic valve.

Patients with rheumatic valvular heart disease who have undergone valve surgery may present later with progression of disease in other valves. We report a case of successful percutaneous transvenous mitral commissurotomy (PTMC) in a 58-year-old male who underwent aortic valve replacement (AVR) with a No. 23 Björk-Shiley valve for severe rheumatic aortic regurgitation in 1982. At AVR, echocardiography revealed mild mitral stenosis (MS) and mitral valve area (MVA) 2.5 cm2. Over 18 years, the mitral valve disease progressed to severe MS and the patient presented with class III exertional dyspnea. He underwent successful PTMC (Inoue balloon technique). Post-procedure echocardiography revealed a MVA of 2.0cm2 and grade II mitral regurgitation. Anticoagulation management, infective endocarditis prophylaxis and procedural modifications are discussed.

Aortic Valve Insufficiency↗

Cytochrome oxidase and ascorbic acid in the normal and regenerating tail of the scincid lizard, Mabuya carinata. A histophysiological study.

The concentration of ascorbic acid (AA) and the histochemical distribution of this vitamin together with cytochrome oxidase have been investigated in the normal and regenerating tail of the Scincid lizard, Mabuya carinata. An interesting aspect of this investigation is the observation of a total lack of cytochrome oxidase in both the normal and regenerating tail of the lizard, except for the differentiating phase. On the other hand, AA has been found to be present in the normal and regenerating tail with above normal levels during wound healing (twofold) and differentiation (fivefold). In the light of the poor cytochrome oxidase activity, the higher content of AA noted during regeneration has been construed to play a possible role in the respiratory mechanics of the regenerating lizard tail. Further, the importance of AA in cellular metabolism and the wound healing and differentiative processes have also been discussed.

Animals↗

Successful radiofrequency ablation of atypical left ventricular outflow tachycardia guided by epicardial activation signals.

A 12-year-old girl, with incessant atypical idiopathic left ventricular tachycardia, underwent successful radiofrequency ablation of ventricular tachycardia focus originating from a subepicardial site adjacent to the left coronary cusp. Ventricular tachycardia was successfully eliminated by targeting an endocardial site concordant to the epicardial site of early activation. Epicardial mapping was useful in locating an effective ablation site, and aortic root angiography was used to avoid potential injury to important structures, such as the left main coronary artery and left coronary cusp.

Catheter Ablation↗