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Biomedical subjects

M Srinivasan

Publications and source records attributed to M Srinivasan.

At least 19 recordsLinked to original sources
PubMed2006

Proximal humeral internal locking system (PHILOS) for the treatment of proximal humeral fractures.

INTRODUCTION: The aim of this study was to describe early results of a new internal locking system, PHILOS, used for the treatment of proximal humeral fractures. MATERIALS AND METHODS: A chart and radiographic review of 25 cases that had proximal humeral internal locking system (PHILOS) plate for the treatment of proximal humeral fractures was performed. RESULTS: Of the 25 cases, 20 went to union with a mean neck/shaft angle of 127.2 degrees . Five cases required or were considered for revision surgery for non-union or implant failure. Of the 25 implants, 4 had screw protrusion into the gleno-humeral joint, 4 had screw loosening and backing out, and 1 plate broke without further trauma. CONCLUSIONS: Our results suggest that PHILOS is an effective system for providing fracture stabilisation to bony union but awareness of potential hardware complications is essential.

Adult↗
PubMed2006

Lycopene as a natural protector against gamma-radiation induced DNA damage, lipid peroxidation and antioxidant status in primary culture of isolated rat hepatocytes in vitro.

The present study was designed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid, on gamma-radiation induced toxicity in cultured rat hepatocytes. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), ceruloplasmin, vitamins A, E, C and uric acid. The DNA damage was analysed by single cell gel electrophoresis (comet assay). The increase in the severity of DNA damage was observed with the increase in gamma-radiation dose (1, 2 and 4 Gy) in cultured rat hepatocytes. TBARS were increased significantly whereas the levels of GSH, vitamins C, E and A, ceruloplasmin, uric acid and antioxidant enzymes were significantly decreased in gamma-irradiated groups. The maximum damage to hepatocytes was observed at 4 Gy irradiation. Pretreatment with lycopene (1.86, 9.31 and 18.62 microM) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes increased significantly along with the levels of GSH, vitamins A, E, C, uric acid and ceruloplasmin. The maximum protection of hepatocytes was observed at 9.31 muM of lycopene pretreatment. Thus, our results show that pretreatment with lycopene offers protection against gamma-radiation induced cellular damage and can be developed as an effective radioprotector during radiotherapy.

Animals↗
PubMed2006

Influence of ferulic acid on gamma-radiation induced DNA damage, lipid peroxidation and antioxidant status in primary culture of isolated rat hepatocytes.

Ionizing radiation is known to induce oxidative stress through generation of reactive oxygen species (ROS) resulting in imbalance of the pro-oxidant and antioxidant activities ultimately resulting in cell death. Ferulic acid (FA) is a phytochemical commonly found in fruits and vegetables such as tomatoes, sweet corn, and ricebran. FA exhibit a wide range of pharmacological effects including antiageing, anti-inflammatory, anticancer, antidiabetic, antiapoptotic, and neuroprotective. The present work is aimed at evaluating the radioprotective effect of FA, on gamma-radiation induced toxicity in primary cultures of isolated rat hepatocytes. Hepatocytes were isolated from the liver of rats by collagenase perfusion. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH), ceruloplasmin, Vitamins A, E and C and uric acid. DNA damage was analyzed by single cell gel electrophoresis (comet assay). An increase in the severity of DNA damage was observed with increasing dose (1, 2 and 4Gy) of gamma-radiation in cultured hepatocytes. TBARS were increased significantly, whereas the levels of GSH, Vitamins C, E and A, ceruloplasmin, uric acid and antioxidant enzymes were significantly decreased in gamma-irradiated groups. The maximum damage to hepatocytes was observed at 4Gy irradiation. Pretreatment with FA (1, 5 and 10 microg/ml) significantly decrease the levels of TBARS and DNA damage. In addition, pretreatment with FA significantly increased antioxidant enzymes, GSH, Vitamins A, E and C, uric acid and ceruloplasmin levels. The maximum protection of hepatocytes was observed at 10 microg/ml of FA pretreatment. Thus, pretreatment with FA helps in protecting the hepatocytes against gamma-radiation induced cellular damage and can be developed as a effective radioprotector during radiotherapy.

Animals↗
PubMed2006

Protective effect of curcumin on gamma-radiation induced DNA damage and lipid peroxidation in cultured human lymphocytes.

The present work is aimed at evaluating the radioprotective effect of curcumin, a naturally occurring phenolic compound on gamma-radiation induced toxicity. The cellular changes were estimated by using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), the antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH). The DNA damage was analysed by using cytokinesis blocked micronucleus assay and dicentric aberration (DC). The gamma-radiation at different doses (1, 2 and 4Gy) were found to significantly increase micronuclei (MN), DC frequencies and TBARS level whereas the levels of GSH and antioxidant enzymes were significantly decreased. The maximum damage to lymphocytes was observed at 4Gy irradiation. Curcumin pretreatment (1, 5 and 10microg/ml) significantly decreased the frequency of MN and DC. The levels of TBARS decreased and activities of SOD, CAT and GPx significantly increased along with GSH levels. At 1Gy irradiation all the concentrations of curcumin (1, 5 and 10microg/ml) significantly protected the lymphocytes from radiation damage. At 2Gy irradiation, 5 and 10microg/ml of curcumin showed significant radioprotection. Since the highest damage was observed at 4Gy irradiation both 1 and 5microg/ml of curcumin pretreatment were not sufficient to protect the lymphocytes from radiation damage but 10microg/ml of curcumin significantly protected the cultured lymphocytes from radiation damage. Thus, pretreatment with curcumin gives protection to lymphocytes against gamma-radiation induced cellular damage.

Adult↗
PubMed2006

Corneal ulceration in south-east Asia III: prevention of fungal keratitis at the village level in south India using topical antibiotics.

AIM: To determine whether topical antifungal prophylaxis distributed by paid village health workers (VHWs) in south India is necessary after corneal abrasion to prevent fungal keratitis in a population where half of the ulcers are fungal. METHODS: Two panchayaths (village administrative units in Madurai district with a combined population of 48 039 were followed prospectively for 18 months by 15 VHWs who were trained to identify post-traumatic corneal abrasions. Patients fulfilling the eligibility criteria were randomised into two groups and treated with either 1% chloramphenicol and 1% clotrimazole ointment or 1% chloramphenicol and a placebo ointment three times a day for 3 days. Patients, doctors and VHWs were blinded to treatment. RESULTS: During the 18-month period, 1365 people reported to VHWs with ocular injuries, of whom 374 with corneal abrasions were eligible for treatment. Of these, 368 (98.5%) abrasions healed without complications. Two patients had mild localised allergic reactions to the ointment, two dropped out and two patients in the placebo group developed microscopic culture-negative corneal stromal infiltrates that healed in 1 week with natamycin drops. CONCLUSIONS: Both fungal and bacterial ulcers that occur after traumatic corneal abrasions seem to be effectively prevented in a village setting using only antibiotic prophylaxis.

Adolescent↗
PubMed2006

Microbiological diagnosis of infective keratitis: comparative evaluation of direct microscopy and culture results.

AIMS: To determine the sensitivity, specificity and predictive values of potassium hydroxide (KOH) wet mount, Gram stain, Giemsa stain and Kinyoun's acid-fast stain in the diagnosis of infective keratitis. METHODS: A retrospective analysis of all patients with clinically diagnosed infective keratitis presenting between September 1999 and September 2002 was carried out. Corneal scrapes were taken and subjected to direct microscopy and culture. RESULTS: 3298 eyes of 3295 consecutive patients with infective keratitis were evaluated, of which 1138 (34.51%) eyes had fungal growth alone, 1069 (32.41%) had bacterial growth alone, 33 (1%) had Acanthamoeba growth alone, 83 (2.5%) had mixed microbial growth and the remaining 975 (29.56%) had no growth. The sensitivity of KOH wet mount was higher (99.3%; 95% confidence interval (CI) 98.6 to 99.6) in the detection of fungi, 100% (95% CI 90.4 to 100) in the detection of Nocardia and 91.4% (95% CI 75.8 to 97) in the detection of Acanthamoeba) than that of Gram-stained smears (89.2% (95% CI 87.3 to 90.8) in fungi, 87% (95% CI 73.0 to 94.6) in Nocardia and 60% (95% CI 42.2 to 75.6) in the detection of Acanthamoeba) in the detection of fungi, Nocardia and Acanthamoeba. 1764 of 3295 (53.54%) patients presented more than 7 days after onset of illness and 84.69% of the eyes had corneal ulcers with size >2 mm in diameter. Positivities of KOH (44.46%; p<0.001) and Gram-stained smears (77.37%; p<0.001) were found to be higher among eyes with larger ulcers (>2 mm) than among eyes with smaller ulcers (<2 mm). CONCLUSION: KOH smear is of greater diagnostic value in the management of infective keratitis, and it is recommended in all clinics without exception for establishing timely treatment.

Acanthamoeba↗
PubMed2006

Corneal ulceration in South East Asia. II: a strategy for the prevention of fungal keratitis at the village level in Burma.

AIM: To prove that topical antifungal and antibiotic prophylaxis distributed by grass roots village health workers (VHWs) in Burma is an effective public health intervention for the prevention of post-traumatic microbial keratitis in a population where the majority of ulcers are fungal. METHODS: Three villages in Bago District with a combined population of 16,987 were selected for the study. This defined population was followed prospectively for 12 months by 15 VHWs who were trained to identify post-traumatic corneal abrasions with fluorescein dye and a blue torch and to administer 1% chloramphenicol and 1% clotrimazole ointment three times a day for 3 days to the eyes of individuals who fulfilled the eligibility criteria. RESULTS: During the 12 month period 273 individuals reported to VHWs with an ocular injury and 126 were found to have a corneal abrasion. All 126 were treated with 1% chloramphenicol and 1% clotrimazole ointment three times a day for 3 days, and all healed without sequelae. CONCLUSIONS: Both fungal and bacterial ulcers that occur following traumatic corneal abrasions can be effectively prevented in a village setting by using relatively simple measures that local volunteer public health workers can easily be taught to employ.

Adolescent↗
PubMed2006

The Antioxidants in Prevention of Cataracts Study: effects of antioxidant supplements on cataract progression in South India.

AIM: To determine if antioxidant supplements (beta carotene and vitamins C and E) can decrease the progression of cataract in rural South India. METHODS: The Antioxidants in Prevention of Cataracts (APC) Study was a 5 year, randomised, triple masked, placebo controlled, field based clinical trial to assess the ability of interventional antioxidant supplements to slow cataract progression. The primary outcome variable was change in nuclear opalescence over time. Secondary outcome variables were cortical and posterior subcapsular opacities and nuclear colour changes; best corrected visual acuity change; myopic shift; and failure of treatment. Annual examinations were performed for each subject by three examiners, in a masked fashion. Multivariate modelling using a general estimating equation was used for analysis of results, correcting for multiple measurements over time. RESULTS: Initial enrolment was 798 subjects. Treatment groups were comparable at baseline. There was high compliance with follow up and study medications. There was progression in cataracts. There was no significant difference between placebo and active treatment groups for either the primary or secondary outcome variables. CONCLUSION: Antioxidant supplementation with beta carotene, vitamins C and E did not affect cataract progression in a population with a high prevalence of cataract whose diet is generally deficient in antioxidants.

Adult↗
PubMed2006

Protective effect of ferulic acid on gamma-radiation-induced micronuclei, dicentric aberration and lipid peroxidation in human lymphocytes.

In this study we examined radioprotective effect of ferulic acid (FA) on gamma radiation-induced dicentric aberration and lipid peroxidation with reference to alterations in cellular antioxidant status in cultured lymphocytes. To establish most effective protective support we used three different concentrations of FA (1, 5 and 10 microg/ml) and three different doses of gamma-radiation (1, 2 and 4 Gy). Treatment of lymphocytes with FA alone (at 10 microg/ml) gave no significant change in micronuclei (MN), dicentric aberration (DC), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) or glutathione peroxidase (GPx) activities when compared with normal lymphocytes; irradiation at 1, 2 and 4 Gy increased the MN and DC frequencies in a dose-dependent manner. Treatment with FA for 30 min before radiation exposure resulted in a significant decline of MN and DC yields as FA concentration increased. Compared to 1 Gy exposure alone, the extent to which FA (1 microg/ml) reduced the MN and DC yields was 75% and 50%, respectively. With 4 Gy irradiation, FA (10 microg/ml) decreased 45% MN and 25% DC frequencies. FA-pretreated lymphocytes (1, 5 and 10 microg/ml) showed progressively decreased TBARS levels after irradiation. Irradiation (1, 2 and 4 Gy) significantly decreased GSH levels, SOD, CAT and GPx activities in a dose-dependent manner. Pretreatment with 10 microg/ml of FA significantly (p<0.05) prevented the decreases in the radiation-induced GSH, SOD, CAT and GPx activities. These findings suggest potential use and benefit of FA as a radioprotector.

Adult↗
PubMed2006

Corneal ulceration in South East Asia. I: a model for the prevention of bacterial ulcers at the village level in rural Bhutan.

AIM: To prove that antibiotic distribution by grassroots volunteer village health workers (VVHWs) in Bhutan is an effective and efficient public health intervention for the prevention of post-traumatic corneal ulceration. METHODS: 55 villages in two districts in Bhutan were selected for the study. A defined population of 10 139 individuals was followed prospectively for 18 months by 31 VVHWs who were trained to identify post-traumatic corneal abrasions with fluorescein dye and a blue torch and to administer 1% chloramphenicol ointment three times a day for 3 days to the eyes of individuals who fulfilled the eligibility criteria. RESULTS: During the 18 month period 135 individuals reported to VVHWs with an ocular injury and 115 were found to have a corneal abrasion. All 115 were treated with 1% chloramphenicol ointment three times a day for 3 days and all healed without sequelae CONCLUSIONS: Corneal ulcers that occur following traumatic corneal abrasions can be effectively prevented, even in the setting of isolated rural conditions such as those that exist in villages in Bhutan, by using relatively simple preventative measures that local VVHWs can easily be taught to employ.

Adolescent↗
PubMed2005

Predictive value of frequency doubling technology perimetry for detecting glaucoma in a developing country.

PURPOSE: To determine the feasibility and diagnostic precision of Frequency Doubling Technology (FDT) perimetry as a method to detect glaucoma in rural villages of a developing country. DESIGN: Cross-sectional study. METHODS: Testing included FDT perimetry (C-20-5 screening protocol), tonometry, anterior segment biomicroscopy, and dilated ophthalmoscopy in 296 rural, non-English speaking residents of Southern India over 35 years old. Participants repeated the FDT if they had a location with reduced sensitivity or an unreliable result. We defined an abnormal FDT as one location of reduced sensitivity present on both the initial and repeat examination. We determined the diagnostic precision of FDT separately for a glaucomatous optic disc, a cup to disc ratio (C/D) > or = 0.7, and a C/D > or = 0.8. RESULTS: Ninety-three percent of subjects were able to complete the test satisfactorily. With repeat FDT testing, 37% of eyes with abnormal FDT results subsequently converted to normal and 67% of eyes with unreliable results subsequently became reliable. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for a glaucomatous optic disc were 7%, 87%, 13%, 76%, and 69%, respectively; for a C/D > or = 0.7, they were 0%, 87%, 0%, 91%, and 81%, respectively; and for a C/D > or = 0.8, they were 0%, 87%, 0%, 99%, and 87%, respectively. CONCLUSION: Clinicians can use FDT perimetry to rapidly screen for glaucoma in rural villages of a developing country. FDT testing had high specificity and negative predictive value, but low sensitivity and positive predictive value. The low sensitivity suggests that FDT has limited applicability as the sole test for glaucoma screening in this population. Repeat testing of FDT results that are unreliable or suspected of being abnormal is beneficial for this screening procedure.

Adult↗
PubMed2005

Ferulic acid, a natural protector against carbon tetrachloride-induced toxicity.

The present work is aimed at evaluating the protective effect of ferulic acid (FA), a naturally occurring phenolic compound on CCl4 induced toxicity. The activities of liver markers (alanine transaminase, aspartate transaminase, alkaline phosphatase, gamma-glutamyl transferase), lipid peroxidative index (thiobarbituric acid-reactive substances, hydroperoxides, nitric oxide, protein carbonyl content), the antioxidant status (superoxide dismutase, catalase, glutathione peroxidase and reduced glutathione) were used as biomarkers to monitor the protective role of FA. The liver marker enzymes in plasma and lipid peroxidative index in liver and kidney were increased in CCl4-treated groups, which were decreased significantly on treatment with FA. The antioxidants, which were depleted in CCl4-treated groups, were improved significantly by FA treatment. Administration of FA to normal rats did not produce any harmful effects. Thus our results show that FA is an effective antioxidant without any side-effects and may be a great gain in the current search for natural therapy.

Animals↗
PubMed2005

Azospirillum brasilense produces the auxin-like phenylacetic acid by using the key enzyme for indole-3-acetic acid biosynthesis.

An antimicrobial compound was isolated from Azospirillum brasilense culture extracts by high-performance liquid chromatography and further identified by gas chromatography-mass spectrometry as the auxin-like molecule, phenylacetic acid (PAA). PAA synthesis was found to be mediated by the indole-3-pyruvate decarboxylase, previously identified as a key enzyme in indole-3-acetic acid (IAA) production in A. brasilense. In minimal growth medium, PAA biosynthesis by A. brasilense was only observed in the presence of phenylalanine (or precursors thereof). This observation suggests deamination of phenylalanine, decarboxylation of phenylpyruvate, and subsequent oxidation of phenylacetaldehyde as the most likely pathway for PAA synthesis. Expression analysis revealed that transcription of the ipdC gene is upregulated by PAA, as was previously described for IAA and synthetic auxins, indicating a positive feedback regulation. The synthesis of PAA by A. brasilense is discussed in relation to previously reported biocontrol properties of A. brasilense.

Azospirillum brasilense↗
PubMed2005

Effect of aqueous Enicostemma littorale Blume extract on key carbohydrate metabolic enzymes, lipid peroxides and antioxidants in alloxan-induced diabetic rats.

The present study investigates the effect of oral administration of an aqueous Enicostemma littorale whole plant extract on some key carbohydrate metabolic enzymes and antioxidant defence in alloxan-induced diabetes in rats. Rats were rendered diabetic by alloxan (150 mgkg(-1) body weight) administration. Oral administration of E. littorale extract for 45 days increased the activity of hexokinase and decreased the activities of glucose 6-phosphatase and fructose 1,6-bisphosphatase significantly in the serum, liver and kidney of diabetic rats. The extract lowered the concentration of thiobarbituric acid reactive substances and lipid hydroperoxides significantly in brain and increased it significantly in heart in diabetic rats. E. littorale administration increased the concentration of reduced glutathione and the activity of glutathione peroxidase in diabetic rats. The activities of superoxide dismutase and catalase were increased significantly by E. littorale treatment in diabetic rats. The effect of a 2 g kg(-1) dose was greater than that of a 1 gkg(-1) dose. Insulin (6 units kg(-1)) normalized all the parameters in diabetic rats. Our study has provided evidence for the antidiabetic activity of E. littorale aqueous extract. This study can also be extrapolated to clinical studies in future.

Alloxan↗
PubMed2005

Susceptibility trends of pseudomonas species from corneal ulcers.

PURPOSE: To assess the changing trends in the antibiotic susceptibility of Pseudomonas spp . isolated from bacterial keratitis over a nine year period with special emphasis on fluoroquinolone susceptibilities. METHODS: All corneal scraping cultures positive for Pseudomonas spp. (n=585) isolated from patients with bacterial keratitis at the Aravind Eye Hospital, Madurai from 1995-2003 were evaluated. Cultures were performed in liquid and solid media and susceptibility testing was done against amikacin, gentamicin, tobramycin, ciprofloxacin and ofloxacin by Kirby-Bauer disc diffusion method. RESULTS: The susceptibility of Pseudomonas spp. was over 90% from 1995-1998 to ciprofloxacin which decreased to 83% from 1999-2003. The total number of isolates resistant to ciprofloxacin was 51 (9.4%). No statistically significant increase in the number of isolates resistant to ciprofloxacin was noted. Ofloxacin showed 54% susceptibility from 1995-1998 but increased to 64% from 1999-2003. Analysis of in vitro activity of amikacin reveals that there was 43% sensitivity from 1995-1998 but later it increased to 76% from 1999-2003. In case of gentamicin, the sensitivity decreased marginally from 80% to 70% through the years. Tobramycin showed 45% sensitivity from 1995-1998 but increased to 75% from 1999-2003. CONCLUSIONS: The fluoroquinolones remain a good choice in the treatment of ocular infections, with high susceptibility of Pseudomonas spp. Among the aminoglycosides, gentamicin was found to be highly effective against Pseudomonas corneal ulcers when compared to amikacin and tobramycin. The results show a need for continuous monitoring of bacterial resistance trends.

Anti-Bacterial Agents↗