Biomedical subjects
Publications and source records attributed to R Balasubramanya.
Human cysticercosis and tuberculosis are endemic diseases in developing countries. Both these diseases have certain common factors of origin. We would like to present the co-existence of these infections in a 20-year-old female. She was a known case of pulmonary and ocular tuberculosis and she acquired cysticercosis of the eye and brain.
PURPOSE: To describe the profile of periorbital trauma in Indian children less than 10 years of age. METHODS: Thirty two children with periorbital injuries were evaluated, over a period of 1 year. Demographic features, mechanism and type of injury were noted. Detailed ophthalmic examination and investigations, including X-ray, ultrasonography, and CT scan were done as needed. Patients requiring secondary intervention were followed-up up to 6 months after surgery. RESULTS: Among the 32 children seen, 20 (63%) were males, 25 of 32 (78%) were between 4 and 7 years of age. Fall was the cause of injury in 31% (10/32) and assault in 28% (9/32). Medial canthal injury was the commonest of all periorbital injuries manifesting as lacrimal drainage obstruction and telecanthus. Associated fractures of the naso-orbital bones were present in 7 patients (22%) and ocular injuries were seen in 18 patients (56%). Secondary intervention was performed in 20 patients and lacrimal drainage procedure was the commonest surgery, performed in 15 out of 20 (75%). CONCLUSION: Periorbital injuries in children not only lead to midfacial deformities and lacrimal drainage obstruction but are associated with significant ocular damage also.
Phospholipase A2 (PLA2) enzymes from snake venoms are approximately 14 kDa secretory proteins and catalyze the release of arachidonic acid which is the precursor of proinflammatory mediators such as prostaglandins, leukotrienes, thromboxanes and platelet-activating factors. The structure of the PLA2 enzyme purified from the venom of Daboia russelli pulchella was determined using molecular replacement method and refined to an R value of 18.3% for all the reflections to 1.8 A resolution. The structure contains two crystallographically independent molecules A and B which form an asymmetric homodimer. The Ca2+ ion was not detected in the present structure, however, a characteristic non-protein high quality electron density was observed at the substrate-binding site of molecule A which allowed a clear interpretation of a natural ligand identified as a derivative of indole, 2-carbamoylmethyl-5-propyl-octahydro-indol-7-yl)-acetic acid. The corresponding substrate-binding site in molecule B was empty. The ligand present in molecule A is involved in extensive interactions with the protein atoms including important catalytic residues such as Asp-49 and His-48. The results also show that the indole derivatives act as potent inhibitors of secretory group II PLA2 enzymes that can be further modified to be used as potential therapeutic agents.
Human cysticercosis is caused by dissemination of embryos of Taenia solium from the intestine via the hepatoportal system to the tissues and organs of the body. We report, probably the first case, where orbital cysticercosis was associated with multiple Cysticercus cellulosae cysts in the brain and subcutaneous tissue. Thorough screening for all the sites of involvement by the cyst is extremely useful for knowing the extent of dissemination, infection control, and for epidemiological purposes.
A severe degree of the aging process in the eyelid and orbital soft tissue complex can lead to extreme weakness or even dehiscence of the supporting fascia and other surrounding soft tissue, rarely leading to free mobility of the orbital fat pads and hence postural herniation into the eyelids as seen in this unusual case.
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A 65-year-old woman was diagnosed clinically to have a tarsal conjunctival malignant melanoma of the upper eyelid. She also had multiple, diffusely pigmented, flat conjunctival lesions. No local or distant metastasis was detected. She was treated conservatively by a combination of surgery and cryotherapy as this was her only seeing eye. Histopathology of the tumor tissue and biopsy specimens of the flat conjunctival lesions proved them to be conjunctival malignant melanoma and primary atypical melanosis with atypia, respectively. Over a follow-up of two years, no clinical recurrence of the tumor was seen. To conclude, a malignant melanoma arising from the tarsal conjunctiva is extremely rare. The goal of treatment should be eradication of the tumor as well as preservation of a functionally and cosmetically acceptable eye.
Periorbital cavernous hemangiomas involving other facial structures usually occur in young adults. We now report a case with multifocal involvement of the eyelid, orbit, conjunctiva, cheek, palate, and temporal fossa, simultaneously, which is quite rare. These lesions are slow-growing and may be associated with systemic abnormalities. Clinical and imaging parameters are employed to differentiate them from other vascular malformations. Depending on the site and severity of the tumor, appropriate treatment modalities are initiated to minimize cosmetic disfigurement and functional deficit in the patient.
AIM: To study the posterior corneal topographic changes in eyes with partial flaps during laser assisted in situ keratomileusis (LASIK). METHODS: Case records of 16 patients, who had partial flap in one eye during LASIK (group 1) and uncomplicated surgery in the other eye (group 2), were studied. Following occurrence of partial flap intraoperatively, laser ablation was abandoned in all the eyes. A 160/180 micro m flap was attempted during the initial procedure using the Hansatome microkeratome (Bausch & Lomb Surgicals, Munich, Germany). LASIK surgery in all cases was performed using a 180 micro m plate, at the mean interval of 4.16 (SD 1.5) months following the initial procedure. None of the eyes had intraoperative complication during LASIK. Relative posterior corneal surface elevation above the best fit sphere (BFS) before the initial procedure, before, and after LASIK were compared using the Orbscan slit scanning corneal topography/pachymetry system. RESULTS: Posterior corneal elevation was comparable in the two groups, both preoperatively (group 1; 16.4 (4.8) micro m, group 2; 16.1 (4.8) micro m) and after final surgery (group 1; 57.2 (15.6) micro m, group 2; 54.3 (13.1) micro m). In group 1 after occurrence of partial flap, the posterior corneal elevation was 16.9 (4.4) micro m, and this increase was not significant statistically (p=0.4). On multiple linear regression analysis, residual bed thickness (p<0.001) was independently the significant determinant of final posterior corneal elevation in both groups. CONCLUSION: The inadvertent occurrence of partial flap during LASIK procedure does not contribute to the increase in posterior corneal elevation.
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AIM: To study the visual performance in eyes with interface haemorrhage during laser assisted in situ keratomileusis (LASIK). METHODS: Case records of 20 patients, who had bleeding from the limbal vessels in one eye during LASIK (group 1) and uncomplicated surgery in the fellow eye (group 2) were studied. The parameters evaluated were uncorrected visual acuity (UCVA) best corrected visual acuity (BCVA), spherical equivalent of refraction (SEQ), contrast sensitivity, and glare acuity preoperatively and at 1, 3, and 6 months postoperatively. RESULTS: The mean preoperative SEQ in group 1 and 2 eyes was -5.79 (2.3) D and -5.27 (1.68) D, respectively. The mean decimal UCVA at 6 months after LASIK in group 1 and 2 eyes were 0.6 (0.2) and 1.0 respectively (p<0.001). The mean decimal BCVA at 1 week after LASIK in group 1 and 2 eyes were 0.89 (0.04) and 1.0 respectively (p<0.05). However, all eyes had a BCVA of 6/6 at 1, 3, and 6 months after LASIK. The mean contrast sensitivity values preoperatively in group 1 and 2 eyes were 161.3 (8.7) and 172 (68.2) respectively. There was a significant decrease in group 1 at 6 months (102 (60.5) (p<0.01)) compared to group 2. The decimal glare acuity preoperatively in group 1 and 2 eyes was 0.95 (0.11) and 0.89 (0.12), respectively. It decreased significantly in group 1 (0.7) (0.1 (p<0.01)) compared to group 2 at the 6 month follow up. CONCLUSION: Occurrence of intraoperative interface haemorrhage may affect the visual performance following LASIK surgery.
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In this prospective clinical study, we treated 8 patients (8 eyes, 11 tumors) of macular retinoblastoma with chemotherapy alone, with the aim of avoiding visual loss because of retinal damage by radiation or adjuvant therapy and to assess their final visual outcome. The mean basal dimension of the tumor was 5.0 +/- 2.6 mm and the mean height was 2.9 +/- 1.3 mm. The fovea was involved in 4 patients (50%) and foveal detachment was present in 3 patients (37.5%). All the patients required less than 6 cycles for tumor control. Four patients (50%) obtained visual acuities ranging from 20/25 to 20/200. Two patients (25%) could gain visual acuity of 20/20. The mean follow-up of patients was 3.24 +/- 0.9 years (range 2-5). No patient developed recurrence or metastatic disease. In conclusion, recent trends for ocular salvage have favored chemoreduction followed by focal therapy for the treatment of retinoblastoma. This study supports the consideration of chemotherapy alone as the primary treatment in eyes with macular retinoblastomas, under close supervision, with satisfactory visual outcome.
A case of cracking of the intraocular lens during insertion is described, a complication not previously reported with single-piece acrylic intraocular lenses. A single large crack was noticed in the center of the intraocular lens optic after the insertion of the lens with a cross-action forceps. The crack developed due to a faulty locking mechanism in the cross-action forceps, which failed to open and release the intraocular lens inside the capsular bag. However, the crack did not cause a decrease in the best-corrected visual acuity of the affected eye.