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Biomedical subjects

J S Mehta

Publications and source records attributed to J S Mehta.

At least 19 recordsLinked to original sources
PubMed2006

Surgical interventions for age-related cataract.

BACKGROUND: Cataract accounts for 50% of blindness globally and remains the leading cause of visual impairment in all regions of the world, despite improvements in surgical outcomes (WHO 2005). This number is expected to rise due to an aging population and increase in life expectancy. Although cataracts are not preventable, their surgical treatment is one of the most cost-effective interventions in healthcare. OBJECTIVES: To compare the effects of different surgical interventions for age-related cataract. SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005, the reference lists of identified trials and we contacted investigators and experts in the field for details of published and unpublished trials. SELECTION CRITERIA: We included randomised controlled trials (RCTS). DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and discrepancies were resolved by discussion. Where appropriate, risk ratios, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies. MAIN RESULTS: We identified 17 trials that randomised a total of 9627 people. Phacoemulsification gave a better visual outcome than extracapsular surgery but similar average cost per procedure in Europe but not in poorer countries. Extracapsular surgery with posterior chamber lens implant and ICCE with or without an anterior chamber intraocular lens (IOL) implant gave acceptable visual outcomes but extracapsular surgery had less complications. Manual small incision surgery provides better visual outcome than ECCE but slightly inferior unaided visual acuity compared to phacoemulsification. AUTHORS' CONCLUSIONS: This review provides evidence from seven RCTs that phacoemulsification gives a better outcome than ECCE with sutures. We also found evidence that ECCE with a posterior chamber lens implant provides better visual outcome than ICCE with aphakic glasses. The long term effect of posterior capsular opacification (PCO) needs to be assessed in larger populations. The data also suggests that ICCE with an anterior chamber lens implant is an effective alternative to ICCE with aphakic glasses, with similar safety. Phacoemulsification provides the best visual outcomes but will only be accessible to the poorer countries if the cost of phacoemulsification and foldable IOLs decrease. Manual small incision cataract surgery provides early visual rehabilitation and comparable visual outcome to PHACO. It has better visual outcomes than ECCE and can be used in any clinic that is currently carrying out ECCE with IOL. Further research from developing regions are needed to compare the cost and longer term outcomes of these procedures e.g. PCO and corneal endothelial cell damage.

Age Factors↗
PubMed2005

Optic disc duplication or coloboma?

AIM: To describe lesions resembling optic disc duplication and highlight their unusual visual fields. The authors also report the first case of pseudo-duplication of the optic disc with overlying retinal nerve fibre layer. METHODS: Retrospective, non-comparative review of case notes. Humphrey visual fields and OCT-3 imaging were performed. RESULTS: All 11 cases represented peripapillary chorioretinal coloboma, some of which lie superior to the optic disc. A double blind spot or superior hemifield defects can be demonstrated by automated visual field testing. CONCLUSION: Clinical examination and identification of bridging retinal vessels from the true optic disc to the second pseudo disc can usually avoid unnecessary invasive and non-invasive investigations.

Adolescent↗
PubMed2005

Hydroxyapatite promotes superior keratocyte adhesion and proliferation in comparison with current keratoprosthesis skirt materials.

AIM: Published clinical series suggest the osteoodontokeratoprosthesis (OOKP) may have a lower extrusion rate than current synthetic keratoprostheses. The OOKP is anchored in the eye wall by autologous tooth. The authors' aim was to compare adhesion, proliferation, and morphology for telomerase transformed keratocytes seeded on calcium hydroxyapatite (the principal mineral constituent of tooth) and materials used in the anchoring elements of commercially available synthetic keratoprostheses. METHODS: Test materials were hydroxyapatite, polytetrafluoroethylene (PTFE), polyhydroxyethyl methacrylate (HEMA), and glass (control). Cell adhesion and viability were quantified at 4 hours, 24 hours, and 1 week using a calcein-AM/EthD-1 viability/cytotoxicity assay. Focal contact expression and cytoskeletal organisation were studied at 24 hours by confocal microscopy with immunoflourescent labelling. Further studies of cell morphology were performed using light and scanning electron microscopy. RESULTS: Live cell counts were significantly greater on hydroxyapatite surfaces at each time point (p<0.04). Dead cell counts were significantly higher for PTFE at 7 days (p<0.002). ss(1) integrin expression was highest on hydroxyapatite. Adhesion structures were well expressed in flat, spread out keratocytes on both HA and glass. Keratocytes tended to be thinner and spindle shaped on PTFE. The relatively few keratocytes visible on HEMA test surfaces were rounded and poorly adherent. CONCLUSIONS: Keratocyte adhesion, spreading, and viability on hydroxyapatite test surfaces is superior to that seen on PTFE and HEMA. Improving the initial cell adhesion environment in the skirt element of keratoprostheses may enhance tissue integration and reduce device failure rates.

Biocompatible Materials↗
PubMed2004

Weight-bearing radiographs in thoracolumbar fractures: do they influence management?

STUDY DESIGN: Prospective observational study. OBJECTIVE: Our objective was to compare supine and erect (weight-bearing) radiographs in patients with thoracolumbar fractures without a neurologic deficit and to determine whether the erect radiographs alter the deformity and the management plan. SUMMARY OF BACKGROUND DATA: Nonoperative treatment for thoracolumbar fracture without a neurologic deficit is safe and effective. There are some guidelines in the literature that provide objective standards to identify the patients that are suitable for nonoperative treatment. These guidelines are based on measurements on supine radiographs. The role of weight-bearing radiographs in influencing the management plan of these injuries has not been explored. METHODS: Fractures between T11 and L2 in 28 patients were considered suitable for nonoperative treatment initially. Radiographic measurements included anterior and posterior vertebral body heights, interpedicular distance, and the Cobb angle on the supine and erect radiographs. A change in the treatment from the initial nonoperative management plan, based on the radiographic findings, was recorded. RESULTS: Mean supine Cobb angle of 11 degrees increased to 18 degrees on weight-bearing films. The mean anterior vertebral compression increased from 34% to 46%. No change was noted between the posterior vertebral heights and the interpedicular distance. Seven of the 28 patients were subjected to surgical stabilization based on these findings. CONCLUSION: Performing erect radiographs in patients with thoracolumbar fractures without a neurologic deficit provides additional information and did alter the management plan in a significant proportion (25%) of our patients.

Adult↗
PubMed2003

Venous leg ulcers after hip replacement. A clinical evaluation at 5 to 12 years.

Venous ulceration is a chronic disabling complication of deep-vein thrombosis. The aim of this study was to estimate the incidence of venous leg ulcers five years or more after total hip replacement (THR) and to investigate some of the clinical features associated with their development. We carried out a postal survey of all patients who had undergone a THR 5 to 12 years previously. Replies from 816 patients showed that 66 (8.1%) had a history of leg ulcers. The prevalence of active ulceration was 2.6% and 43 patients (5.3%) reported developing ulceration since their hip replacement. A clinical review determined that 31 (3.8%) of these were true venous ulcers. The ulcers occurred more commonly on the operated side and developed at a mean of 5.8 years (18 months to 12 years) after the first arthroplasty. A mean of 1.9 arthroplasties (1 to 5) (primary and revision) were carried out before the ulcers appeared. The overall incidence of ulcers was similar to that in the general population.

Aged↗
PubMed2002

The sclera, the prion, and the ophthalmologist.

Prions have emerged in the past 5 years as serious transmissible infective agents. Ocular tissue transplantation has come under scrutiny after potential infected tissue was transplanted into healthy patients. In this review we examine the evidence for the risk of transmission of prions after scleral transplantation and explore alternative materials that may be used in ocular surgery.

Creutzfeldt-Jakob Syndrome↗
PubMed2001

Latent proliferative sickle cell retinopathy in sickle cell trait.

PURPOSE: To describe a patient with sickle cell trait who developed latent proliferative sickle cell retinopathy after mild blunt trauma. METHOD: Case Report. A 20-year-old man with unilateral Stage 3 sickle retinopathy associated with an ischaemic ridge presenting three years after the initial mild blunt ocular trauma. RESULTS: Fundus examination of the left eye showed an ischaemic ridge delineating avascular from vascular retina. Fluorescein angiography of the left eye showed an avascular peripheral retina and multiple sea fan neovascularization. Blood studies showed him to be Hb AS. CONCLUSIONS: In our patient the proliferative changes were the result of his initial mild trauma associated with an increase in the intraocular pressure. The latent development of the sea-fan neovascularization associated with an ischaemic ridge is unusual. Advice about potential complications to patients with Hb AS after ocular trauma is advocated.

Eye Injuries↗
PubMed2001

Tuberculosis of the thoracic spine. A classification based on the selection of surgical strategies.

In spinal tuberculosis MRI can clearly demonstrate combinations of anterior and posterior lesions as well as pedicular involvement. We propose a classification system, using information provided by MRI, to help to plan the appropriate surgical treatment for patients with thoracic spinal tuberculosis. We describe a series of 47 patients, divided into four groups, based on the surgical protocol used in the management. Group A consisted of patients with anterior lesions which were stable with no kyphotic deformity, and were treated with anterior debridement and strut grafting. Group B comprised patients with global lesions, kyphosis and instability who were treated with posterior instrumentation using a closed-loop rectangle with sublaminar wires, and by anterior strut grafting. Group C were patients with anterior or global lesions as in the previous groups, but who were at a high risk for transthoracic surgery because of medical and possible anaesthetic complications. These patients had a global decompression of the cord posteriorly, the anterior portion of the cord being approached through a transpedicular route. Posterior instrumentation was with a closed-loop rectangle held by sublaminar wires. Group D comprised patients with isolated posterior lesions which required posterior decompression only. An understanding of the extent of vertebral destruction can be obtained from MRI studies. This information can be used to plan appropriate surgery.

Adolescent↗