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Biomedical subjects

G K Das

Publications and source records attributed to G K Das.

17 recordsLinked to original sources
PubMed2003

Comparative randomised controlled clinical trial of a herbal eye drop with artificial tear and placebo in computer vision syndrome.

A comparative randomised double masked multicentric clinical trial has been conducted to find out the efficacy and safety of a herbal eye drop preparation, itone eye drops with artificial tear and placebo in 120 patients with computer vision syndrome. Patients using computer for at least 2 hours continuosly per day having symptoms of irritation, foreign body sensation, watering, redness, headache, eyeache and signs of conjunctival congestion, mucous/debris, corneal filaments, corneal staining or lacrimal lake were included in this study. Every patient was instructed to put two drops of either herbal drugs or placebo or artificial tear in the eyes regularly four times for 6 weeks. Objective and subjective findings were recorded at bi-weekly intervals up to six weeks. Side-effects, if any, were also noted. In computer vision syndrome the herbal eye drop preparation was found significantly better than artificial tear (p < 0.01). No side-effects were noted by any of the drugs. Both subjective and objective improvements were observed in itone treated cases. So, itone can be considered as a useful drug in computer vision syndrome.

Adult↗
PubMed2001

Evaluation of Ophthacare eye drops--a herbal formulation in the management of various ophthalmic disorders.

An open prospective multicentre clinical trial was conducted in patients suffering from various ophthalmic disorders namely, conjunctivitis, conjunctival xerosis (dry eye), acute dacryocystitis, degenerative conditions (pterygium or pinguecula) and postoperative cataract patients with a herbal eye drop preparation (Ophthacare) containing basic principles of different herbs which have been conventionally used in the Ayurvedic system of medicine since time immemorial. These include Carum copticum, Terminalia belirica, Emblica officinalis, Curcuma longa, Ocimum sanctum, Cinnamomum camphora, Rosa damascena and meldespumapum. These herbs reportedly possess antiinfective and antiinflammatory properties. The present study was undertaken to elucidate the role of this herbal product in a variety of eye ailments. Side effects, if any, were noted during the study. An improvement was observed with the treatment of the herbal eye drop treatment in most cases. There were no side effects observed during the course of the study and the eye drop was well tolerated by the patients. The herbal eye drop Ophthacare has a useful role in a variety of infective, inflammatory and degenerative ophthalmic disorders.

Adult↗
PubMed2000

Therapy of acanthamoeba keratitis--an experimental study.

The study was conducted to determine the efficacy of various drugs/agents in the treatment of experimentally induced Acanthamoeba Keratitis (A. keratitis). Thirty rabbits were divided into 5 equal treatment groups and polyhexamethylene biguanide (PHMB) 0.02%, fluconazole 0.2%, povidone iodine 5%, aprotinin 40 IU/ml and normal saline were administered in a double blind manner, at a dose of one drop, 5 times/day. Neomycin 1700 U/ml was used as a common drug in all groups, with same frequency. Post therapy subsidence of lid oedema, mucopurulent discharge, conjunctival congestion, corneal epithelial defect and anterior chamber reactions were noted. Average healing time in days (Mean +/- S.D.) were 13.67 +/- 1.21, 22 +/- 1.41, 23.5 +/- 1.05, 17.0 +/- 1.41 and 28.0 +/- 1.90 for PHMB, fluconazole, povidone iodine, aprotinin and normal saline respectively. Lid oedema, mucopurulent discharge and conjunctival congestion improved faster in PHMB and aprotinin treated eyes. The results of this study suggest that PHMB is a better drug for A. keratitis, while aprotinin may be used as an adjuvant drug in the management of A. keratitis.

Acanthamoeba Keratitis↗
PubMed1999

A possible mechanism of peptide bond formation on ribosome without mediation of peptidyl transferase.

Ribosome, the ubiquitous organelle, is the site for protein synthesis in all types of cells. The consecutive peptide bonds are formed by the transpeptidation reaction between carboxyl group of peptidyl moiety and the amino group of the aminoacyl moiety. Both the moieties are attached to the appropiate tRNAs positioned on the ribosome at P and A sites, respectively, through codon-anticodon recognition directed by messenger RNA. The reaction seems to proceed by the nucleophillic attack of the amino group of the aminoacyl tRNA at the A site and on the carboxyl of the ester group of the tRNA at P-site of ribosome. The configuration of the carbon atom of the tetrahedral intermediate may be R or S depending on the direction of the nucleophillic attack. After selecting the favorable conformation of this tetrahedral intermediate quantum mechanical calculations have been carried out to determine the energy needed for its formation. A cyclic intermediate where 2'-OH of the ribose sugar of the P-site tRNA is a member of the ring can be formed from the tetrahedral intermediate. This cyclic intermediate produces a free tRNA and a tRNA attached to a planar peptide unit. Analysis of the energetics using semiempirical method for the formation of a cyclic intermediate indicates that the peptide bond formation through the tetrahedral intermediate in S configuration may not need assistance from any outside agent like an enzyme

Humans↗
PubMed1999

Animal study on the effects of catalin on aftercataract and posterior capsule opacification.

PURPOSE: To find out the role of Catalin in the prevention of posterior capsular opacification (PCO), we undertook this experimental study in rabbits. METHODS: Twenty rabbits (10 for the Catalin group and 10 for the placebo group) were operated on for extracapsular clear lens extraction in an aseptic environment. In all cases, capsulorrhexis of 8 mm diameter was carried out. Both the test drug and placebo were given at a dose of 4 times/day from the first postoperative day for 8 weeks. Common drugs in both groups were topical corticosteroid, antibiotic and cycloplegic drops. Periodic slitlamp examinations and photographic documentations were carried out to find any evidence of aftercataract. At the end ot 8 weeks, histopathological examination was carried out to document any evidence of aftercataract. RESULT: Overall, evidence of aftercataract was seen in 6 rabbits in the control group and 3 in the Catalin group; the degree of PCO was higher in the placebo group. CONCLUSION: We found that Catalin played some role in preventing PCO.

Animals↗
PubMed1998

Randomized trial of intraoperative mitomycin C in surgery for pterygium.

PURPOSE: To report the efficacy and safety of intraoperative application of mitomycin C in surgery for pterygium. METHODS: In a prospective randomized and double-blind study done within a span of 2.5 years in 50 eyes (50 patients) with primary progressive pterygium, mitomycin C in a concentration of 0.02 mg/ml soaked in a sterile 5 x 5-mm sponge was applied over the bare sclera intraoperatively as an adjuvant therapy in 25 eyes after pterygium excision. These cases were compared with another 25 similar eyes that underwent the same procedure but in which gentamicin solution 0.3% was used instead of mitomycin C solution. RESULTS: Three eyes (12%) in the mitomycin C group showed recurrence within 7 months of surgery compared with eight eyes (32%) of the gentamicin control group within 3 to 5 months. Mild side effects, such as pain, photophobia, and delayed wound healing, were observed within the first 1 to 2 weeks postoperative in both groups. In the mitomycin C-treated group, corneal changes in the form of superficial punctate keratitis (three eyes) and limbal avascularity (two eyes) subsided within 2 weeks postoperatively. Follow-up time for these cases ranged from 18 to 21 months. CONCLUSIONS: A diluted solution of mitomycin C, 0.02 mg/ml, with an accurate size of sterile sponge applied to bare sclera after primary pterygium excision decreases the rate of recurrence to a greater extent than does gentamicin solution and is not associated with severe complications.

Adult↗
PubMed1998

Corneal infection after radial keratotomy.

PURPOSE: To evaluate nine eyes that developed corneal infection after radial keratotomy (RK) and their subsequent management. SETTING: Dr. Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi, India. METHOD: The parameters evaluated were interval between RK and development of the ulcer, number of keratotomy incisions, nature of surgery (primary or secondary), status at presentation, and best corrected visual acuity (BCVA). Corneal scrapings were taken from all eyes for microbiological evaluation. Initial therapy was based on clinical impression and subsequent therapy, on the microbiological report. RESULTS: Staphylococcus species were the most frequently isolated bacteria followed by Pseudomonas aeruginosa. Two eyes had fungal growth, and no organisms were isolated from one. All but one eye responded to medical therapy; healing took 23 to 26 days. Therapeutic penetrating keratoplasty (PKP) was done in one eye. Presenting BCVA of hand movement to 6/36 improved to hand movement to 6/18 after the ulcer healed. Final BCVA was 6/36 to 6/9 after lamellar keratoplasty or PKP or with contact lens of spectacle correction. CONCLUSION: Our study shows that corneal infection is a potential complication of RK. Therefore, persistent postoperative irritation should be carefully observed to ensure early diagnosis and prompt therapy.

Adolescent↗
PubMed1996

Comparative double blind multicentric randomised placebo controlled clinical trial of a herbal preparation of eye drops in some ocular ailments.

A double masked placebo controlled multicentric randomised clinical trial was conducted in 157 patients suffering from different eye ailments namely, cataract, dry eye syndrome, ocular asthenia, refractive errors and allergic conjunctivitis with a herbal eye drop preparation and placebo. In both dry eye syndrome and ocular asthenia the herbal eye drop preparation was found better than placebo. In a few cases of cataract, the vision seems to be improved. In early myopia it seems to correct the refractive errors while in high myopic conditions it controlled the progressive deteriorations. Subjective improvements were also noted with hypermetropia, presbyopia and astigmatism. Its healing capacity in allergic conjunctivitis was certainly better than placebo. It had no short term or long term side-effects. It is considered to be a useful drug in all conditions studied.

Double-Blind Method↗
PubMed1995

Efficacy of four antiviral agents in the treatment of uncomplicated herpetic keratitis.

OBJECTIVE: To evaluate the efficacy of four antiviral agents--1% idoxuridine ointment (group 1), 2% trifluorothymidine ointment (group 2), 3% acyclovir ointment (group 3) and 1% bromovinyldeoxyuridine (BVDU) ointment (group 4)--in herpes simplex keratitis. DESIGN: Randomized double-blinded clinical trial. SETTING: Tertiary care institution in New Delhi. PATIENTS: Eighty patients with uncomplicated herpes simplex keratitis of recent onset who had not previously received antiviral treatment. MAIN OUTCOME MEASURES: Cure rate, frequency and severity of side effects. RESULTS: Cure rates of 60%, 90%, 90% and 95% were obtained in groups 1, 2, 3 and 4 respectively. The average healing time was 13.4, 8.9, 8.5 and 7.5 days respectively. Side effects (follicular conjunctivitis, epithelial keratopathy and stinging) were more frequent in group 1 than in the other groups. CONCLUSIONS: BVDU has a more pronounced therapeutic effect than idoxuridine, trifluorothymidine and acyclovir in uncomplicated epithelial herpetic disease of recent onset that has not previously been treated.

Acyclovir↗
PubMed1995

Comparative double masked randomised placebo controlled clinical trial of a herbal eye drop preparation in trachoma and conjunctivitis.

A double blind controlled clinical trial has been done with a herbal eye drop preparation in case of trachoma stage III and chronic conjunctivitis of the eyes. In both trachoma and chronic conjunctivitis, the herbal eye drop formulation proved its superiority over placebo. Side-effects (burning sensations) were observed with normal saline which was used as placebo. But no side-effects were observed in the patients of trachoma and conjunctivitis who got the active drug. Both objective and subjective improvements were observed with the herbal eye drop preparation.

Conjunctivitis↗
PubMedDate not supplied

Peptidyl transferase activity of tRNA: a quantum chemical study.

The mechanism of protein synthesis is still unknown due to inability to detect the so-called enzyme "peptidyl transferase" even after elucidation of high-resolution crystal structure of ribosome. We have recently shown by model building and semi-empirical energy calculation that the tRNA molecule at P-site of ribosome may act as peptidyl transferase (Das et al. (1999) J. Theor. Biol. 200, 193-205). We proposed that the tetrahedral intermediate formed from nucleophylic attack of CO of P-site amino-acylated tRNA by NH2 of A-site amino-acylated tRNA is converted to a six-member ring intermediate by conformational change. This ring intermediate produces a free tRNA and a tRNA covalently linked to a peptide. However, energy of the six-member ring intermediate was calculated to be quite high. We show here that the energy values of all the reactants, intermediates and products are within the expected range when they are calculated using high level ab initio quantum chemical methods.

Alanine↗
PubMedDate not supplied

Therapeutic penetrating keratoplasty in nonhealing corneal ulcer.

Results of penetrating keratoplasty in 443 eyes of 439 patients of active infective corneal ulcers, from a period of 10 years, were analyzed. All these eyes were proven refractory to maximal medical therapy for extended periods of time, in some cases more than 6 weeks. As the surgery was performed during the active stage, the outcome was not favorable functionally. Clinical cure was obtained, however, by therapeutic penetrating keratoplasty in all but 27 of these eyes. Of unsuccessful cases, 16 could be saved with additional medical therapy, two led to phthisis bulbi, and nine required repeat therapeutic penetrating keratoplasty. Complications encountered included disturbances in intraocular dynamics such as extrusion of the lens and vitreous during surgery, secondary rise of intraocular pressure leading to damage of the optic nerve, loss of the eye due to above factors, and reinfection. The anatomical success achieved was 97% with graft clarity of 2+ or more in 39% of eyes. Useful vision, ie, better than or equal to 6/60, was possible in 33% of eyes. Thus, therapeutic keratoplasty in refractory corneal ulcer still has scope in a Third-World country.

Adolescent↗