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Biomedical subjects

C M Kalavathy

Publications and source records attributed to C M Kalavathy.

14 recordsLinked to original sources
PubMed2006

Prevention of selenite-induced cataractogenesis by acetyl-L-carnitine: an experimental study.

Several studies have suggested that antioxidants retard the process of cataractogenesis by scavenging free oxygen radicals. The present study sought to assess the efficacy of the antioxidant acetyl-L-carnitine (ALCAR) in preventing selenite-induced cataractogenesis in an experimental setting. The first, in vitro phase of the study was performed on lenses from Wistar rats incubated for 24 h at 37 degrees C in Dulbecco's Modified Eagle Medium (DMEM) alone (control, Group I), or in DMEM containing 100 microM of selenite (Group II) or in DMEM containing 100 microM of selenite and 200 microM/ml ALCAR added at the same time as selenite (Group IIIa) or 30 min, 1 h or 2 h later (Groups IIIb, IIIc and IIId, respectively). Gross morphological examination of these lenses revealed dense opacification (cataract formation) in Group II, minimal opacification in some Group IIIa lenses and no opacification in Group I. The mean activities of the antioxidant enzymes catalase and glutathione peroxidase were significantly lower in Group II than in Group I or Group IIIa lenses, while malondialdehyde concentration (an indicator of lipid peroxidation) was significantly higher in Group II lenses than that in Group I or Group IIIa lenses. The second, in vivo phase of the study revealed dense opacification (cataract formation) in 100% of Wistar rat pups receiving subcutaneous sodium selenite alone (19 microM/kg body weight) but in only 37.5% of those receiving subcutaneous selenite and intraperitoneal ALCAR. These data suggest that ALCAR is able to significantly retard experimental selenite-induced cataractogenesis.

Acetylcarnitine↗
PubMed2006

Microbial keratitis at extremes of age.

PURPOSE: To study the risk factors, clinical presentation, response to treatment and outcome of microbial keratitis occurring in patients at extremes of age (ie, children and the elderly) and to compare them with microbial keratitis affecting the general adult population. METHODS: In this prospective, nonrandomized, analytical clinical study, all patients presenting with microbial keratitis and undergoing microbiological workup over a 1-year period were evaluated using a dedicated corneal ulcer protocol. Patients were divided into 3 groups based on age: (1) pediatric group if the age was 16 years or younger, (2) elderly group if the age was 65 years or older, and (3) control group if the age was between 17 and 64 years. Features studied included microbiological profile, predisposing factors, clinical presentation, response to treatment, and final visual outcome. RESULTS: A total of 269 eyes of 269 patients were studied (26 in the pediatric group, 55 in the elderly group, and 188 in the control group). Culture positivity rates were similar in all the groups. The elderly and control groups had a similar incidence of fungal and bacterial keratitis, but the pediatric group had a significantly lower incidence of fungal keratitis (P = 0.001). Trauma was the most common predisposing factor in all groups. Elderly patients tended to present with a higher incidence of central ulcers (P = 0.04), severe ulcers (P = 0.04), and poor visual acuity (P = 0.003) as compared with the control group. The percentage of ulcers healing with medical treatment alone was significantly more in the pediatric group (P = 0.004), while the incidence of poor visual outcome was greater in the elderly group (P = 0.006) as compared with the control group. CONCLUSIONS: Microbial keratitis in pediatric patients is more likely to be of bacterial etiology, and nonsevere ulcers in this age group have a better chance of resolution with medical therapy alone when compared with that in the general adult population. Conversely, elderly patients with microbial keratitis tend to present with severe, central ulcers with a significant risk of having a poor visual outcome.

Adolescent↗
PubMed2005

Comparison of in vitro susceptibilities of ocular bacterial isolates to gatifloxacin and other topical antibiotics.

PURPOSE: To compare the in vitro activity of gatifloxacin with that of other topical antibiotics against fresh bacterial isolates from various types of human ocular infections. METHODS: A total of 498 strains of ocular bacterial isolates were tested for their susceptibility to gatifloxacin, ofloxacin, ciprofloxacin, norfloxacin, gentamicin, tobramycin, neomycin, chloramphenicol, erythromycin, tetracycline and amikacin. RESULTS: Ninety-nine percent of gram-positive and 92% of gram-negative bacterial strains were found to be susceptible in vitro to gatifloxacin, whereas lower percentages of gram-positive and gram-negative bacteria were found to be susceptible to other antibiotics. CONCLUSIONS: In vitro, gatifloxacin exhibits good activity against various bacterial species isolated from different ocular sites. This requires corroboration in the clinical setting.

Anti-Infective Agents, Local↗
PubMed2005

Outcome analysis of cataract surgery following therapeutic keratoplasty.

PURPOSE: To assess the results of cataract surgery, in terms of visual outcome and effect on graft survival, in eyes that have previously undergone therapeutic penetrating keratoplasty for infective keratitis. METHODS: Case records of patients who had undergone cataract surgery alone (group A) or in combination with regrafting (group B) following initial therapeutic penetrating keratoplasty between January 2000 and December 2001 were reviewed retrospectively. Main outcome measures studied were visual acuity, astigmatism, and effect of the cataract surgery on graft survival. Results were compared with eyes undergoing cataract surgery after optical keratoplasty and between eyes in groups A and B. RESULTS: Frequency of cataract surgery after therapeutic keratoplasty was significantly greater than that following optical keratoplasty [68 (52%) versus 47 (21%); P<0.001]. Fifty-eight eyes of 58 patients undergoing cataract surgery after therapeutic penetrating keratoplasty were analyzed in detail. Mean follow-up period was 8.9 months (+/-7.6 months). Thirty eyes underwent cataract surgery alone (group A), and 28 eyes underwent cataract surgery with regrafting (group B). Eyes that had undergone therapeutic keratoplasty were significantly more likely to have opaque grafts requiring regrafting at the time of cataract surgery than eyes that had undergone optical keratoplasty [28 (48.3%) versus 5 (10.6%); P<0.001]. Incidence of graft failure after cataract surgery did not differ significantly in eyes that had undergone therapeutic or optical keratoplasty. Final visual acuity at last follow-up was 6/12 or better in 25 eyes (43%). There were no significant differences between eyes in groups A and B in terms of final visual acuity, astigmatism, or graft failure rates. CONCLUSIONS: Visual results of cataract surgery following therapeutic keratoplasty are comparable to those following optical keratoplasty. Combining a repeat keratoplasty for a failed graft with the cataract surgery does not significantly affect the final outcome.

Adolescent↗
PubMed2005

Comparison of topical itraconazole 1% with topical natamycin 5% for the treatment of filamentous fungal keratitis.

PURPOSE: To compare the clinical efficacy of itraconazole 1% eyedrops with a standard therapy regimen (natamycin 5% eyedrops) for topical monotherapy of fungal keratitis. METHODS: Patients presenting with suspected uniocular microbial keratitis over a period of 12 months (January to December 2002) underwent detailed clinical examination and microbiological investigation. One hundred consecutive patients with direct smear- and/or culture-proven fungal keratitis were enrolled in the study after obtaining informed consent. The ulcers were categorized as severe or nonsevere. The first 50 consecutive patients received primary therapy with topical natamycin hourly, and the next 50 consecutive patients received topical itraconazole hourly. The primary efficacy criteria were the physician's judgment of clinical success, cure rate, and the rate of treatment failure. RESULTS: The diagnosis of fungal keratitis was established by positive microscopy and culture findings in 88 patients and by positive microscopy alone in 12 patients. Species of Fusarium, Aspergillus, and Curvularia were the principal isolates. Thirty-six (72%) of 50 patients (28 of 37 with nonsevere keratitis and 8 of 13 with severe keratitis) showed a favorable response to primary natamycin therapy (mean duration, 20.5 days), while 30 (60%) of 150 patients (25 of 38 with nonsevere keratitis and 5 of 12 with severe keratitis) exhibited a favorable response to primary itraconazole therapy (mean duration, 23.1 days). In keratitis due to Fusarium spp, 19 (79%) of 24 patients showed a favorable response to natamycin, which was significantly greater than the 8 (44%) of 18 patients who showed a favorable response to itraconazole (P < 0.02). However, no such difference was evident in keratitis due to Aspergillus spp or Curvularia spp; in keratitis due to Aspergillus spp, favorable responses were noted in 6 (54.5%) of 11 patients receiving natamycin and 5 (50%) of 10 patients receiving itraconazole, while in keratitis due to Curvurlaria spp, such responses occurred in both patients receiving natamycin and in 8 (89%) of 9 patients receiving itraconazole. Both antifungal formulations were generally well tolerated with no obvious adverse effects. CONCLUSIONS: Topical natamycin should continue to be considered as the treatment of choice for filamentous fungal keratitis; when natamycin is unavailable, topical itraconazole therapy could be used, particularly if the infections are due to Aspergillus or Curvularia spp.

Administration, Topical↗
PubMed2004

Keratitis due to a coelomycetous fungus: case reports and review of the literature.

PURPOSE: To describe a series of 7 patients with ulcerative keratitis caused by species of Colletotrichum, which are coelomycetous fungal pathogens. METHODS: The patients presented with keratitis of varying degrees of severity. Multiple scrapes from the corneal lesions of 6 of the 7 patients were used for microbiological investigations by a standard protocol. In the seventh patient, scraping was not performed due to the presence of deep infiltration and a descemetocele at presentation. All 7 patients were hospitalized and treatment was initiated with topical applications of natamycin (5%) and ciprofloxacin (0.3%) every hour and cyclopentolate (1%) drops 3 times daily. An emergency therapeutic penetrating keratoplasty was performed after 48 hours in the patient who had presented with a descemetocele and for another patient whose keratitis did not respond to 10 days of medical therapy. RESULTS: The corneal samples of all 7 patients yielded significant growth of filamentous fungi in culture. On the basis of macroscopic and microscopic characteristics, the fungal isolates were identified as Colletotrichum spp. Corneal lesions completely resolved with medical therapy alone in 5 patients. In the 2 patients who had undergone therapeutic penetrating keratoplasty, the infection was eradicated and the corneal graft remained clear even after several months of follow-up. CONCLUSION: Colletotrichum spp may be more frequent causes of keratitis than previously thought. Keratitis due to Colletotrichum spp frequently responds to medical therapy alone, although surgery may be indicated in a small proportion of patients.

Adolescent↗
PubMed2002

Aetiology of suppurative corneal ulcers in Ghana and south India, and epidemiology of fungal keratitis.

BACKGROUND: A multicentre study was carried out in Ghana and southern India to determine the aetiology of suppurative keratitis in two regions located at similar tropical latitudes. Studies of fungal keratitis from the literature were reviewed. METHODS: Patients presenting at rural and urban eye units with suspected microbial keratitis were recruited to the study. Corneal ulceration was defined as loss of corneal epithelium with clinical evidence of infection with or without hypopyon. Microscopy and culture were performed on all corneal specimens obtained. RESULTS: 1090 patients were recruited with suspected microbial keratitis between June 1999 and May 2001. Overall the principal causative micro-organisms in both regions were filamentous fungi (42%): Fusarium species and Aspergillus species were the commonest fungal isolates. Pseudomonas species were most frequently isolated from cases of bacterial keratitis in Ghana but in India the commonest bacterial isolates were streptococci. CONCLUSION: Infections of the cornea due to filamentous fungi are a frequent cause of corneal damage in developing countries in the tropics and are difficult to treat. Microscopy is an essential tool in the diagnosis of these infections. A knowledge of the "local" aetiology within a region is of value in the management of suppurative keratitis in the event that microscopy cannot be performed.

Aspergillosis↗
PubMed1987

Itraconazole therapy for fungal keratitis.

110 cases of keratomycosis were treated with itraconazole administered either orally or topically or by both routes. Excellent or moderate response was obtained in 69 percent of the patients. Ulcers due to Aspergillus and dematiaceous fungi and non-sevee ulcers responded better than did severe ulcers and ulcers due to Fusarium. A combination of oral and topical itraconazole yielded the highest percentage of excellent or moderate responses.

Adolescent↗
PubMedDate not supplied

Bilateral Pseudomonas keratitis without predisposing factors.

Bilateral keratitis usually occurs in predisposed individuals such as contact lens wearers, those suffering from malnutrition and immunodeficiency or patients undergoing bilateral refractive corneal surgery. We report a 30-year-old man without any obvious predisposing factors who presented with complaints of pain and decreased vision in both eyes. Examination revealed corneal ulcers in both eyes, which on microbiological culture grew Pseudomonas aeruginosa. The patient underwent a therapeutic keratoplasty in the right eye while the left eye was managed medically. Bilateral Pseudomonas keratitis can develop in the absence of any obvious predisposing factors.

Adult↗