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Biomedical subjects

G P Rao

Publications and source records attributed to G P Rao.

At least 19 recordsLinked to original sources

Validation of a handheld automated keratometer in adults.

PURPOSE: To evaluate the Nidek handheld automated keratometer and compare it with the manual Zeiss keratometer. SETTING: St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. METHODS: Forty-five normal adult volunteers were included in the study. Three sets of randomized keratometry measurements were taken from both eyes of each adult, with both instruments by two independent observers. Readings included powers of the steep and flat meridians and axis of the flat meridian. The mean difference between the two instruments was calculated. The variance of each instrument was calculated for the axis, the steep and flat meridians, and the mean of the two meridians. RESULTS: There was no significant difference between the mean Nidek and Zeiss keratometry readings for the steep (0.015 mm; P = .167) or flat (0.054 mm; P = .069) meridian or axis measurements (P = .172). On repeated measurements, the within-subject and within-group variabilities, calculated separately for each instrument, were significantly less for the Nidek automated keratometer than the Zeiss keratometer (P < .01) when measuring the steep and flat meridians. There was however, a significant increase in axis variability using the Nidek keratometer (range 20 degrees; P < .01). CONCLUSION: The Nidek automated keratometer was accurate, reliable, and easy to use and compared favorably with the manual Zeiss keratometer when measuring corneal curvature. In the handheld mode, the Nidek is not suitable for axis measurements. It has the additional advantage of portability.

Adult↗

Local anaesthesia for vitreoretinal surgery: a case-control study of 200 cases.

PURPOSE: In the United Kingdom the majority of vitreoretinal (VR) surgery is performed under general anaesthesia (GA). The aim of this study was to demonstrate the scope of local anaesthesia (LA) for VR surgery, to measure the acceptance of LA to patients and surgeons and to compare the surgical outcomes, complication rates and duration of the surgical procedures under LA and GA. METHODS: A case-control study was undertaken to compare 100 cases performed under LA with 100 matched cases performed under GA. The matching of cases was based on multiple criteria such as configuration and complexity of retinal detachment, the involvement of the macula, the number and site of retinal tears, presence and severity of proliferative vitreoretinopathy, experience of the surgeon and the type of the surgical procedure. A clinical audit was also carried out on 65 successive patients using a questionnaire to determine the acceptability of LA to patients and surgeons. RESULTS: Anatomical and visual success rates, and intra-operative and post-operative complications, were similar in cases carried out under LA and GA. The mean duration of the surgery (excluding anaesthetic time) was significantly shorter for LA than GA procedures (p < 0.001). The acceptance for LA was high for both patients and the operating surgeons. CONCLUSIONS: We found that VR surgery can be safely and efficiently performed under LA. Adoption of LA has increased our throughput.

Anesthesia, General↗

Technique of removal of an impacted sharp object in a penetrating head injury using the lever principle.

Penetrating head injuries can be difficult to manage as the extensive surgery which may be required can result in severe morbidity and mortality in some patients. A conservative surgical approach with a "pull and see" policy was adopted successfully in a described case. Extraction can be achieved by using the mechanical advantage of the lever principle. By this method while removing the object any movements of sharp edges which will cause secondary damage can be reduced to a minimum.

Brain Injuries↗

Surgical management of lower-lid basal cell carcinoma involving the medial canthus: a modification of the Mustarde cheek rotation flap.

The Mustarde cheek rotation flap has proved to be an extremely successful and reliable technique for repairing large defects of the lower lid. However, when a stump of normal, lash-bearing lid margin remains on the advancing edge of the flap, it does not seem appropriate to insert it into a defect that extends more medially than the position of the lower punctum. The lid margin must either be sacrificed or tissue brought in from the medial side to meet it. To resolve this problem, we have devised a modification, which involves utilizing the triangle of tissue lying below the defect to fill the gap medial to the position of the punctum. The maneuver has proved successful and has now been used on two occasions with satisfactory cosmetic and functional results. In this original descriptions of the cheek rotation flap, Mustarde sacrificed the triangle of skin below the excision defect. However, if a triangular portion is saved, based on the upper part of the advancing edge of the flap, this may be used to fill a medial defect, obviating the need to import tissue from elsewhere.

Aged↗

Central corneal endothelial guttae and age-related macular degeneration: is there an association?

The similarities between the corneal endothelium and retinal pigment epithelium in terms of their embryology, barrier function and predilection to age-related degeneration prompted this investigation into a possible association between central corneal guttae (CCG) and age-related macular degeneration (ARMD). 50 patients with clinically significant CCG were prospectively evaluated for the presence of ARMD. 51 age-matched patients attending for unrelated ailments who did not have CCG were also evaluated for the presence of drusen and other signs of ARMD. Of the 50 patients with CCG, 23 had bilateral ARMD and 4 had unilateral ARMD. In the control group, 9 patients had bilateral and 4 had unilateral ARMD. There was significant difference in the prevalence of ARMD between patients with CCG and those with no CCG (p = 0.017 and p < 0.001 for right and left eyes respectively). We found an association between CCG and ARMD. The presence of CCG in a patient may imply increased risk for the presence of ARMD. In a patient with CCG requiring cataract or corneal surgery, the successful outcome may be compromised by the presence of ARMD.

Adult↗

Microbial models of mammalian metabolism. Biotransformations of HP 749 (besipirdine) using Cunninghamella elegans.

HP 749 (besipirdine; Hoechst-Roussel Pharmaceuticals, Inc., Somerville, NJ) and related analogs belonging to the N-(4-pyridinyl)-1H-indol-1-amine class of compounds have shown a potential to mitigate multiple biochemical deficits associated with Alzheimer's disease. HP 749 has demonstrated cholinergic and nonadrenergic activities both in vitro and in vivo, and has potential for the symptomatic treatment of Alzheimer's disease. The three primary metabolites of HP 749 in dogs, rats, and humans result from hydroxylation of the indole ring, N-dealkylation of the parent compound, and sequential hydroxylation and dealkylation. The fungus Cunninghamella elegans (ATCC 36112) converts 25% of HP 749 in a dextrose broth to yield four metabolites, three of which have been reported in mammalian systems. Preparative scale fermentation allowed for the isolation of the major fungal metabolite resulting from hydroxylation of the indole nucleus at position 5 (16%), which was characterized by cochromatographic (TLC and HPLC), 1H-NMR, mass spectral (chemical ionization/MS), and UV comparisons to a synthetic standard. Additional minor fungal metabolites were formed as a result of N-dealkylation (2%), and sequential N-dealkylation and aromatic hydroxylation (2.5%). C. elegans is being used as a model to help predict and generate the logical mammalian metabolites of related structural analogs of HP 749.

Animal Testing Alternatives↗

Ophthalmic manifestations of Rathke's cleft cysts.

PURPOSE: We studied the neuro-ophthalmic features of patients with symptomatic Rathke's cleft cysts, to distinguish features of Rathke's cleft cysts from those of craniopharyngioma. METHODS: Eleven patients who had undergone surgery for symptomatic Rathke's cleft cysts in the Liverpool University Department of Neurological Science were identified from the records. Histopathologic analyses, clinical notes, and radiologic investigations were reviewed. RESULTS: Eight of the 11 patients initially had visual problems. Reduced visual acuity, visual field defect, or both, were detected in nine patients. Optic atrophy was observed in eight patients. Other initial features included headaches, epilepsy, and endocrine disturbance. All patients recovered from surgery, and an improvement in the visual acuity or visual field defect was noted in six patients. CONCLUSIONS: Symptomatic Rathke's cleft cysts often manifest as visual disturbance. Every effort to distinguish Rathke's cleft cysts from craniopharyngiomas should be made preoperatively. Rathke's cleft cysts only require limited surgical intervention, and radiotherapy is not necessary. Early recognition and treatment can lead to improvement in visual function.

Adolescent↗

Paradoxical progression of tuberculous lesions during chemotherapy of central nervous system tuberculosis. Report of four cases.

The peculiar phenomenon of paradoxical progression during the treatment of central nervous system tuberculosis is discussed. A few cases with this phenomenon were reported in the past, and the authors have treated four such cases. During the treatment for tuberculous meningitis, the four patients developed new lesions, mainly in the form of tuberculomas, which progressed for some time and later regressed. In all these cases the initial drug regimen was not changed, except for the addition of steroids for a short period at the time of deterioration. All four patients underwent ventriculoperitoneal shunt insertion during the course of treatment. The authors discuss the significance of the changes in the lesions and management of such cases, and review the literature.

Adolescent↗