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Dinesh Verma

Publications and source records attributed to Dinesh Verma.

7 recordsLinked to original sources
PubMed2006

Shiga toxin exposure modulates intestinal brush border membrane functional proteins in rabbit ileum.

The activities of lactase, sucrase and alkaline phosphatase (AP) were studied in intestinal brush border membranes of control and toxin-treated rabbits. Purified Shiga toxin (Stx) exposure to ileal mucosa inhibited activities of brush border enzymes by 50%. Kinetic analysis revealed that the observed decrease in BBM enzyme activities was due to reduced V(max) with no change in the affinity constants of the systems. The observed changes in enzyme activities were corroborated by Western Blot analysis of lactase, sucrase and AP. The mRNA levels encoding sucrase and lactase proteins in control and Shiga toxin-treated rabbit ileum did not show any change in the rabbit ileum. Histopathological analysis showed short, blunt villi with increased number of inflammatory cells in the lamina propria and extrusion of cells in to the lumen of Stx-treated rabbit ileum. The present findings suggest that Shiga toxin act by inhibiting protein synthesis of these brush border functional proteins beyond their transcriptional level and by the direct damage to intestinal epithelium, which could be implicated in the pathogenesis of diarrhea.

Alkaline Phosphatase↗
PubMed2005

Effect of preoperative counseling on patient fear from the visual experience during phacoemulsification under topical anesthesia: Multicenter randomized clinical trial.

PURPOSE: To determine whether preoperative counseling about potential intraoperative visual experience during phacoemulsification under topical anesthesia reduces fear in patients having cataract surgery. SETTING: The Eye Institute at Tan Tock Seng Hospital, Singapore, Royal Hull Hospitals NHS Trust, Kingston-upon-Hull, and Manchester Royal Eye Hospital, Manchester, United Kingdom. METHODS: In this prospective multicenter randomized clinical trial, patients with cataracts having elective phacoemulsification under topical anesthesia were recruited and randomized into 2 groups. Both groups received routine preoperative counseling regarding risks and benefits of cataract surgery. One group received additional counseling on the potential intraoperative visual experience during phacoemulsification; the other group did not. The patients were then interviewed within 24 hours following phacoemulsification regarding their intraoperative experience. RESULTS: Two hundred nineteen patients were recruited over an 11-month period. There were 104 men and 115 women. The mean age was 68 years (range 20 to 89 years). There were 188 Singaporeans, comprising 168 Chinese, 13 Malays, and 7 Indians, and 31 British patients, all of whom were white. The mean fear score was 0.3 in the group that received additional counseling and 0.9 in the group that did not receive additional counseling (P = .036). The effect of counseling on fear was significant (P = .002) even after controlling for sex, age, and whether first or second cataract surgery. CONCLUSIONS: Preoperative counseling about the potential intraoperative visual experience during phacoemulsification under topical anesthesia helped to reduce the fear from the visual sensations in patients having cataract surgery.

Adult↗
PubMed2004

Virtual vitreoretinal surgical simulator as a training tool.

OBJECTIVE: To demonstrate the feasibility and potential applicability of a virtual reality simulator for vitreoretinal surgery as a training and/or assessment tool. METHODS: The subjects of this study included medical students, ophthalmologic residents, and trained vitreoretinal surgeons. There were three study groups. Group I comprised 22 subjects who performed a navigation task. The time to complete the task was recorded. The relationship between the completion time, experience, and stereopsis was evaluated. Group II included 6 subjects who consecutively performed the navigation task to evaluate their learning curve. Group III included 16 subjects who performed the membrane peeling task. The number of retinal contacts and the completion time were recorded. The relationship between experience and stereopsis with the number of contacts and the completion time were evaluated. RESULTS: The average completion time in Group I for students, residents, and trained surgeons was 121.6, 92.5, and 70.6 seconds. There was a significant difference between students and trained surgeons (P = 0.004). In Group II, there was a significant decrease in the completion time with training (P = 0.001). In Group III, the average completion time for students, residents, and trained surgeons was 197, 144, and 118.2 seconds; the respective number of retinal contacts was 14, 8, and 3. There was a significant difference between students and residents (P = 0.05) and between residents and trained surgeons (P = 0.003) for the average completion time in Group III. There was a significant difference between students and trained surgeons (P = 0.003) for the number of contacts per average time and between students and residents (P = 0.05). There was a significant inverse correlation between stereopsis vision score and completion time in Group I and number of contacts per average time (P = 0.0004 and P = 0.01, respectively). CONCLUSIONS: This study demonstrates potential applications of a vitreoretinal surgical simulator as a training and skills assessment tool for novice, inexperienced, and trained surgeons. A simulator can be used to teach specific techniques and train surgeons.

Adult↗
PubMedDate not supplied

An investigation of CO2 laser scleral buckling using moiré interferometry.

BACKGROUND AND OBJECTIVE: To demonstrate suitability of moiré interferometry to assess and quantify laser-induced shrinkage of scleral collagen for buckling procedures. MATERIALS AND METHODS: Scleral buckling of human cadaver eyes was investigated using a Coherent Ultrapulse CO2 laser. Projection moiré interferometry was employed to determine the out-of plane displacement produced by laser exposure, and in-situ optical microscopy of reference markers on the eye was used to measure in-plane shrinkage. RESULTS: Measurements based on moiré interferometry allow a three dimensional view of shape changes in the eye surface as laser treatment proceeds. Out-of-plane displacement reaches up to 1.5 mm with a single laser spot exposure. In-plane shrinkage reached a maximum of around 30%, which is similar to that reported by Sasoh et al (Ophthalmic Surg Lasers. 1998;29:410) for a Tm:YAG laser. CONCLUSION: The moiré technique is found to be suitable for quantifying the effects of CO2 laser scleral shrinkage and buckling. This can be further developed to provide a standardized method for experimental investigations of other laser sources for scleral shrinkage.

Cadaver↗