Biomedical subjects

N Mohan

Publications and source records attributed to N Mohan.

At least 19 recordsLinked to original sources

PubMed2006

Induction of systemic resistance in Lycopersicon esculentum cv. PKM1 (tomato) against Cucumber mosaic virus by using ozone.

Studies were undertaken to evaluate ozone (O(3)) for induction of resistance against Cucumber mosaic virus in Lycopersicon esculentum cv. PKM1 (tomato) plants. Callus induced from tomato leaf explants on Murashige & Skoog's (MS) medium supplemented with benzyladenine (8.82 microM) were treated with different concentrations of ozone T(1), T(2), T(3) and for control (C), filtered air was supplied. Regeneration of shoots was obtained by culturing ozone treated calli on MS medium containing 17.3 microM benzyladenine. The frequency of regeneration of tomato plants from the callus were T(1)=79%, T(2)=61%, T(3)=42%, but for control 90% regeneration was obtained. Regenerated plants were rooted in half strength MS medium supplemented with 10 microM indole-butyric acid and successfully acclimatized. The plants regenerated from ozone treated callus are referred to as T(1), T(2) and T(3) plants, which hold remarkably increased soluble phenolic content compared to the control plants. All the plants were challenged by mechanical inoculation with Cucumber mosaic virus, shows disease incidence ranged from T(1)=32%, T(2)=56%, T(3)=78% and C=94%. Remarkable increase in activities of salicylic acid (SA), phenylalanine ammonia-lyase (PAL) and peroxidase (POX) were detected after Cucumber mosaic virus inoculation, in foliar extracts of T(1) plants than T(2) and T(3), compared to the control plants.

Chlorophyll↗

PubMed2006

In situ electrocatalytic oxidation of acid violet 12 dye effluent.

Electrochemical treatment of organic pollutants is a promising treatment technique for substances which are recalcitrant to biodegradation. Experiments were carried out to treat acid violet 12 dye house effluent using electrochemical technique for removal color and COD reduction covering wide range in operating conditions. Ruthenium/lead/tin oxide coated titanium and stainless steel were used as anode and cathode, respectively. The influence of effluent initial concentration, pH, supporting electrolyte and the electrode material on rate of degradation has been critically examined. The results indicate that the electrochemical method can be used to treat dye house effluents.

Catalysis↗

PubMed2004

Electrochemical removal of chromium from wastewater by using carbon aerogel electrodes.

A study has been carried out to determine the feasibility of electrochemical removal of chromium ions from industrial wastewater using carbon aerogel electrodes. In this work the effect of key variables including pH (2-7), concentration 2-8 (mg/l), and charge 0.3-1.3 (A h) was determined. The metal ion removal was significantly increased at reduced pH and high charge conditions. The metal concentration in the wastewater can be reduced by 98.5% under high charge (0.8A h) and acidic conditions (pH 2). The effect of the independent parameters--pH, effluent concentration and charge on the percentage removal was depicted by a quadratic equation obtained using Box-Behnken model. The regression analysis gave a R2 value of 0.9469 shows a close fit between the experimental results and the model predictions. The model was further used to optimise the parameters to maximise the percentage Cr-removal to more than 98%.

Carbon↗

PubMed2003

Degradation of (+)-catechin by Acinetobacter calcoaceticus MTC 127.

Acinetobacter calcoaceticus MTC 127 was able to grow on catechin and protocatechuic acid (PCA) as sole carbon source. Cells induced with catechin oxidized catechin and PCA at rates higher than cells of uninduced cultures. Two aromatic compounds, PCA and phloroglucinol carboxylic acid (PGCA) were isolated from culture filtrate of cells grown in catechin and characterized by infrared spectrometry and high performance thin-layer chromatography. Moreover, A. calcoaceticus MTC 127 produced high levels of PCA compared to PGCA in the degradation of catechin. Based upon these results, a pathway for the degradation of (+)-catechin in A. calcoaceticus MTC 127 is proposed. Enzymes extracted from catechin-induced culture showed catechin oxygenase (cox) and protocatechuate 3,4-dioxygenase (pcd) activities. Catechin oxygenase was purified by column chromatography and SDS-PAGE analysis showed a single band with an apparent molecular weight of 47 kDa.

Acinetobacter calcoaceticus↗

PubMed2003

Cloning of Acinetobacter calcoaceticus chromosomal region involved in catechin degradation.

Acinetobacter calcoaceticus utilizes catechin as sole carbon source. The chromosomal region involved in catechin catabolism was cloned in Escherichia coli DH5alpha from the genomic DNA of A. calcoaceticus. A recombinant E. coli containing 9.2 kb DNA fragment of A. calcoaceticus inserted in pUC19 showed a halo zone around the colony in plate assays, indicating the catechin utilizing ability of the clone. Enzyme assays revealed the expression of the cloned DNA fragment of A. calcoaceticus. High performance thin layer chromatography confirmed protocatechuic acid and phloroglucinol carboxylic acid as cleavage products of catechin in A. calcoaceticus and the catechin degrading ability of the clones. A. calcoaceticus followed the beta-ketoadipate pathway for catechin degradation. The sub-clone (pASCI) of this insert was sequenced and analyzed. The sequence showed three major ORFs but only ORF 2 showed similarities to other aromatic oxygenases and the sequence of ORF 2 was submitted to GenBank (AF369935).

Acinetobacter calcoaceticus↗

PubMed2003

Progress in treatment and outcome for children with neonatal haemochromatosis.

AIM: To evaluate the role of antioxidant treatment and liver transplantation in the management of neonatal haemochromatosis. METHODS: A retrospective review was performed of eight infants with acute liver failure and raised ferritin levels between 1990 and 1998. From 1994, treatment with an antioxidant cocktail (vitamin E, N-acetylcysteine, selenium, prostaglandin E1, and desferrioxamine) was begun once the diagnosis was suspected. Pathological and other findings were reviewed, and outcome before and after antioxidant treatment was evaluated. RESULTS: Median age at presentation was 4 days with median ferritin levels of 4180 micro g/l (range 1650-40 000 micro g/l; normal range 110-503 micro g/l). Three infants presented before 1994. One infant died before liver transplantation from acute liver failure and one from neurological damage after transplantation. The third patient underwent successful transplantation at day 13 and remains well on follow up 8 years later. From 1994, five patients received antioxidant treatment, of whom two responded: both responders started antioxidants earlier (by day 5) than non-responders and had lower peak ferritin levels (< 4200 micro g/l) and a milder phenotype. Treatment was continued until ferritin levels were < 500 micro g/l. Both children remain well with mean follow up of 42 months, with no recurrence of iron overload. One child showed a partial response to treatment and survived long enough for a liver transplant, but died from graft failure after the transplant. Two children did not respond to antioxidant treatment; both had multiorgan failure and were not listed for transplantation. Only three of the eight patients survived (37.5%) over this time period. CONCLUSION: Neonatal haemochromatosis can be a fatal disease with > 60% mortality. Early treatment with antioxidant cocktail is beneficial and may be curative in those who present with milder phenotype. Liver transplantation should always be considered at an early stage in non-responders and in children with more severe acute liver failure.

Antioxidants↗

PubMed2003

Effect of phenol on ultra structure and plasmid DNA of Xanthomonas oryzae pv. oryzae.

Most phenolic substances of plant origin are toxic to microorganisms and they confer some degree of protection to plants against phytopathogens. Xanthomonas oryzae pv. oryzae, bacterial blight pathogen of rice (Oryza sativa) was treated with phenol (monohydroxy benzene) and its effects on the morphology and cytological changes of the bacterium were studied. Total lysis of cells occurred with 5 mM conc of phenol while at 2 mM conc, the cell walls became rough and cell contents started shrinking. Plasmids isolated from both treated (2 mM) and control cells did not show any marked difference under electron microscope except that they differed in their quantity and might influence pathogenicity.

Chromosomes, Bacterial↗

PubMed2003

Influence of Adyar river in the coastal waters of Chennai (Madras), Bay of Bengal.

The impact of the river Adyar which is influenced by industrial wastes and domestic sewage from the city of Chennai (Madras), on the hydrobiology of coastal water in the Bay of Bengal was evaluated. Reduction in pH, dissolved oxygen (DO), nitrite, nitrate, primary productivity and increase of ammonia, phosphate, silicate, heavy metals, biological oxygen demand (BOD), chlorophyll pigments, particulate organic carbon (POC), respiration, suspended solids, ATP, and bacteria in the mixing site during low tide indicated that the Adyar water was heavily polluted and ultimately affect the quality of coastal water near the vicinity of mixing zone. The effects are diluted or nullified as the distance increased from the mixing site due to heavy mixing and littoral current. During high tide, the flow was completely stopped and little or no effect was recorded. The light, water current and wave action are the important factors which minimize the pollution impacts in the receiving coastal water.

Ammonia↗

PubMed2002

Is routine splintage following primary total knee replacement necessary? A prospective randomised trial.

It was hypothesised that routine splintage following primary total knee replacement has no affect on flexion deformity and offers no benefit over simple wool and crepe. Fifty-five patients undergoing primary total knee replacement were entered into a prospective study. The patients were randomly assigned to two groups: The first group was rehabilitated without a splint and the second received an adjustable semi-rigid extension splint (Richards splint) for the first 48 h after surgery. Range of motion measurements were recorded pre-operatively and at 2 days, 1 week and 3 months post-operation by a research nurse blinded to the allocation. No statistically significant difference in flexion deformity was found at any stage (P>0.5). No difference was found in general or wound complications, or requirement for blood transfusion, and the post-operative stay was equal in the two groups. We conclude that routine use of a semi-rigid splint following primary total knee replacement has no advantage over simple wound dressings.

Aged↗

PubMed2002

Jaundice clearance and cholangitis in the first year following portoenterostomy for biliary atresia.

Sixty-one patients with biliary atresia, who underwent portoenterostomy (PE) between 1992 to 1998 in the Institute of Pediatrics, Kuala Lumpur and were followed for a period of one year, were studied to analyze the factors associated with jaundice clearance and cholangitis following PE. Sex distribution was equal. Majority of patients were Malays. Mean age in days at admission to the surgical ward was 66.90 +/- 23.36 and mean age at PE was 75.85 +/- 24.05. At the end of one-year follow-up, six patients (10%) had died, 35 (57%) developed one or more attacks of cholangitis, 35 (57%) had portal hypertension, eight (13%) liver failure and six patients had esophageal variceal bleeding. Thirty-three patients (54%) had jaundice clearance with a mean clearance time of 85 days after PE. The study shows that when the ductules in the porta hepatis were < 150 mu in size, persistence of jaundice after PE and the incidence of cholangitis in the first post-operative year were higher; patients with cholangitis in the first year had lower rate of jaundice clearance. Jaundice clearance was achieved in more patients when their postnatal age at the time of PE was lower but the relationship was not linear. Age at PE also did not have a linear temporal relationship to the incidence of cholangitis and the size of portal ductules. Prospective, multi-center based local studies on a bigger patient population are needed to identify other indicators of successful outcome following PE. This would help to define the indications for primary liver transplantation in the local population.

Biliary Atresia↗

PubMed2002

Knowledge, attitude and practices towards HIV among nurses in a tertiary care teaching hospital: two decades after the discovery.

Accidental transmission of HIV infection to health care workers during occupational exposure is a real threat today. The first such case in India has been documented by NACO recently. Adequate knowledge about the disease and practice of safety measures are our best bet to reduce such transmission. A survey was carried out amongst over 500 nurses in a tertiary care referral hospital in Delhi to assess their knowledge, attitude and practices towards HIV/AIDS. While overall knowledge was satisfactory, there were gaping holes in vital areas. The conversion of their theoretical knowledge into safe practices was shockingly poor. It was due to attitude problems as much as inadequate supplies. High incidence of accidental exposures in the near past and complete ignorance of post-exposure prophylaxis guidelines was another highlight of this study. Despite tremendous efforts put in by the Government as well as various Non-Governmental Organizations, we are completely ill equipped to fight the menace of occupational HIV transmission. In order to fight this menace, "safe practices" have to be made a "way of life" for HCWs. Our health care planners need to take note of it and our teaching and training programmes need complete re-orientation to achieve this goal.

Adult↗

PubMed2001

Demyelination occurring during anti-tumor necrosis factor alpha therapy for inflammatory arthritides.

OBJECTIVE: To review the occurrence of neurologic events suggestive of demyelination during anti-tumor necrosis factor alpha (anti-TNFalpha) therapy for inflammatory arthritides. METHODS: The Adverse Events Reporting System of the Food and Drug Administration (FDA) was queried following a report of a patient with refractory rheumatoid arthritis who developed confusion and difficulty with walking after receiving etanercept for 4 months. RESULTS: Nineteen patients with similar neurologic events were identified from the FDA database, 17 following etanercept administration and 2 following infliximab administration for inflammatory arthritis. All neurologic events were temporally related to anti-TNFalpha therapy, with partial or complete resolution on discontinuation. One patient exhibited a positive rechallenge phenomenon. CONCLUSION: Further surveillance and studies are required to better define risk factors for and frequency of adverse events and their relationship to anti-TNFalpha therapies. Until more long-term safety data are available, consideration should be given to avoiding anti-TNFalpha therapy in patients with preexisting multiple sclerosis and to discontinuing anti-TNFalpha therapy immediately when new neurologic signs and symptoms occur, pending an appropriate evaluation.

Adult↗

PubMed2001

Topical ciprofloxacin-dexamethasone combination therapy after cataract surgery: randomized controlled clinical trial.

PURPOSE: To determine the efficacy of a combination of ciprofloxacin 0.3% and dexamethasone 0.1% eyedrops in controlling immediate inflammation after cataract surgery. SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences and Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India. METHODS: This randomized controlled clinical trial comprised 61 patients, 31 of whom were treated with a combined ciprofloxacin-dexamethasone suspension (study group) and 30, with a standard formulation of betamethasone and neomycin eyedrops (control group). One and 7 days postoperatively, pain, lid edema, lacrimation, conjunctival congestion, aqueous flare and cells, and side effects were noted. A conjunctival swab for bacteria and a fungus culture were sent for evaluation 7 days postoperatively. RESULTS: At 7 days, there was no statistically significant difference between groups in lid edema, conjunctival congestion, anterior segment inflammation, lacrimation, or pain. Two patients in the ciprofloxacin-dexamethasone group noted white deposits in and around the eye that resolved after the dose was reduced to 4 times a day. No patient reported or developed an allergic reaction to either drug combination. CONCLUSION: A ciprofloxacin-dexamethasone combination was effective in controlling inflammation after cataract surgery.

Administration, Topical↗

PubMed2001

Diagnosis of vasculitis.

Vasculitis is a process that results from the inflammation of blood vessels and can occur de novo or secondary to a variety of diseases or drugs. Clinical presentation depends on the size and distribution of vessels involved. Anti-neutrophil cytoplasmic antibodies (ANCA) have been shown to have variable sensitivity in making the diagnosis of specific vasculitic syndromes, therefore histological confirmation may be necessary. Angiography is a useful tool in evaluating disease of large and medium-sized vessels that are inaccessible or potentially dangerous to biopsy. New imaging modalities are becoming more useful in diagnosing vessel wall changes, particularly in large-vessel vasculitides. In clinical practice it is not always possible to classify or apply a specific label to a patient with vasculitis, but for appropriate patient management it is important to define the extent and severity of disease and to exclude underlying secondary causes.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed2001

Electrochemical oxidation of resorcinol for wastewater treatment using Ti/TiO2-RuO2-IrO2 electrode.

Electrochemical oxidation of resorcinol for wastewater treatment in the presence of chloride was investigated. Titanium Substrate Insoluble Anode (TSIA) coated with TiO2-RuO2-IrO2 was used as an anode and graphite carbon sheet was used as a cathode. The extent of resorcinol electrochemical oxidation was determined in terms of COD removal. The Box-Behnken second order composite design was used to study the effect of operating parameters such as initial pH, chloride concentration, initial concentration of resorcinol and charge input. The experimental values were in good correlation with predicted values, and the correlation coefficient was found to be good. The effect of current density on resorcinol oxidation, the AOX level during the electrochemical treatment and TOC removal were also studied for selected conditions. It has been observed that the extended electrolysis brings down the AOX concentration to lower levels. The maximum current efficiency was observed at higher resorcinol concentration, higher chloride concentration and increasing current density.

Chlorides↗

PubMed2001

Effect of phenol on protein and amino acid content of Xanthomonas oryzae pv. oryzae.

Leaf blight disease of rice (Oryza sativa) is caused by the bacterium Xanthomonas oryzae pv. oryzae. Phenol (1 to 4 mM) induced changes in protein profiles of X. o. pv. oryzae and a stress protein with a molecular mass of 69,000 appeared. HPLC analysis indicated occurrence of amino acids such as asparagine, alanine, methionine and cystine in phenol treated cells. Proton NMR analysis also revealed variation on the presence of amino acids in the cells treated with phenol.

Amino Acids↗

PubMed2001

Effect of phenol on lipid and fatty acid profile of Xanthomonas oryzae pv. oryzae.

Effect of phenol on total lipid and fatty acid composition of Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice (Oryzae sativa) was studied. Lipid level was low in phenol treated cells. Number of fatty acids detected from phenol treated cells was more than those found in untreated cells as revealed by Gas chromatography. Pentadecanoic acid (C15:0), linolenic acid (C18:3) and behenic acid (C22:0) were present only in the treated cells. Palmitic acid which is usually found in bacteria was not detected both in control and treated cells.

Electrophoresis, Polyacrylamide Gel↗

PubMed2000

Spectrum of giant cell vasculitis.

Giant cell arteritis (GCA) is the commonest primary systemic vasculitis in the United States. Severe outcomes include blindness and stroke, and death may result from aortic dissection. Temporal artery biopsy remains the gold standard for diagnosis. Magnetic resonance imaging (MRI) of involved vessels shows promise as a useful noninvasive method for diagnosis and assessment of disease activity. Corticosteroid therapy is effective but is associated with considerable morbidity. Longitudinal studies with large numbers of patients are required to identify appropriate steroid-sparing agents. New insights into the immunopathogenesis of GCA have allowed us to identify heterogeneous subsets of patients with varying clinical presentations corresponding to specific cytokine profiles. The concept of the involved artery as an active participant in the events leading to luminal obstruction has been realized and provides the opportunity to evaluate novel therapies to modify the course of the disease.

Adult↗