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Biomedical subjects

Rahul N Khurana

Publications and source records attributed to Rahul N Khurana.

17 recordsLinked to original sources
PubMed2007

A novel method to oxygenate intraocular irrigation fluids with an in-line oxygenator.

PURPOSE: We describe a novel method to oxygenate intraocular irrigation solutions involving an in-line oxygenator. METHODS: Either lactated Ringer (LR) solution or balanced salt solution (BSS) was oxygenated with the FE390 Stainless In-line Oxygenation Assembly (Beer, Beer, and More Beer, Concord, CA). After running a 100-mL of solution through the in-line oxygenator, oxygen saturation was measured with a dissolved oxygen meter. A control experiment involving the oxygenator without oxygen perfusion was performed. Paired t-tests were used to compare oxygen saturation changes before and after oxygenation. RESULTS: In comparison with the original BSS, there was an increase in oxygen saturation of 162 +/- 47% (n = 40; P < 0.05). Without oxygenation perfusion, there was only a 24 +/- 14% (n = 40) increase in oxygen levels in BSS, which was significantly lower than that in treated BSS (P < 0.05). In comparison with the original LR solution, there was an increase in oxygen saturation of 208 +/- 21% (n = 40; P < 0.05). Without oxygenation perfusion, there was only a 21 +/- 9% (n = 40) gain in oxygen saturation in the control LR solution, which was statistically lower as well (P < 0.05). CONCLUSION: The in-line oxygenator is an efficient tool for oxygenating BSS and LR solution. It represents a potential efficient and convenient method to oxygenate irrigating solutions for vitreoretinal surgeries.

Acetates↗
PubMed2007

Effect of oxygenated intraocular irrigation solutions on the electroretinogram after vitrectomy.

PURPOSE: To investigate the effect of oxygenated intraocular irrigating solutions on electroretinograms (ERGs) for postvitrectomy rabbits. METHODS: Eight groups of five rabbits each underwent pars plana vitrectomy on the right eye; the left eye of each rabbit served as control. The intraocular irrigating solutions were balanced salt solution (BSS), BSS-plus, BSS + oxygen (BSS + O2), BSS-plus + O2, and combinations of each with the addition of endoillumination (L). All animals were evaluated by single-flash scotopic electroretinography on the operated and nonoperated eyes before surgery and at 1 hour, 1 day, 1 week, and 1 month after surgery by an unmasked observer. The main outcome measures were dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios. The results for the different groups were compared by analysis of variance. RESULTS: Mean dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios +/- SD for BSS-plus and BSS-plus + O2 before surgery and 1 hour, 1 day, 1 week, and 1 month after surgery were 1.01 +/- 0.09, 0.50 +/- 0.11, 0.95 +/- 0.11, 0.97 +/- 0.11, and 0.99 +/- 0.08 and 0.98 +/- 0.08, 0.59 +/- 0.10, 0.92 +/- 0.06, 0.97 +/- 0.08, and 0.97 +/- 0.10, respectively. At both 1 hour and 1 day after surgery, rabbits treated with BSS-plus + O2 had an earlier b-wave return to baseline findings, but the differences were not statistically significant (P > 0.05). Mean dark-adapted b-wave amplitudes of operated eye/nonoperated eye ratios +/- SD for BSS and BSS + O2 before surgery and 1 hour, 1 day, 1 week, and 1 month after surgery were 1.02 +/- 0.10, 0.47 +/- 0.09, 0.77 +/- 0.07, 0.89 +/- 0.07, and 0.89 +/- 0.07 and 1.02 +/- 0.06, 0.62 +/- 0.16, 0.94 +/- 0.09, 0.97 +/- 0.08, and 0.96 +/- 0.06, respectively. One hour and 1 day after surgery, ERG readings for rabbits treated with BSS + O2 exhibited a statistically significantly earlier return of ERG voltage to baseline values compared with both BSS and BSS + L (P = 0.05 and P = 0.02, respectively). One day after surgery, rabbits treated with BSS alone had the lowest ERG ratios. One week and 1 month after surgery, for all solutions tested other than BSS, ERG values were within normal limits. CONCLUSION: The use of oxygenated solutions appears to affect ERG readings after pars plana vitrectomy. Further studies to evaluate the role of oxygenated solutions in different vitreoretinal surgical procedures are warranted.

Acetates↗
PubMed2006

Syphilis: reemergence of an old adversary.

OBJECTIVE: To describe the clinical findings in 4 patients with ocular syphilis and to provide a review of the recent rise in syphilis cases in the United States, along with a brief description of current diagnosis and treatment guidelines. DESIGN: Retrospective, observational case series. PARTICIPANTS: Four consecutive patients who presented to our facility during a 6-month interval in 2005 with ocular syphilis. METHODS: Review of clinical, laboratory, photographic, and angiographic records of patients with neurosyphilis who underwent intravenous penicillin G treatment. MAIN OUTCOME MEASURES: Resolution of signs and symptoms of ocular syphilis, including changes in visual acuity. RESULTS: Four patients (3 male: mean age, 46 [range, 39-60 years]; 1 female: age 46 years) demonstrated cerebrospinal fluid findings consistent with neurosyphilis, as evidenced by increased leukocyte counts (>5 white blood cells/mm3), and positive Venereal Disease Research Laboratory or serum fluorescent treponemal antibody absorbed tests. All 4 patients presented with a variety of clinical findings that led to a delay in diagnosis and treatment. Two patients presented with discrete placoid lesions consistent with acute syphilitic posterior placoid chorioretinitis, a manifestation typically observed among the immunocompromised. CONCLUSIONS: Despite a decade of steady decline, syphilis has reemerged in the United States with outbreaks throughout the country in the past few years. Ocular findings, including posterior placoid chorioretinitis, are important diagnostic features in the early treatment of tertiary syphilis and neurosyphilis. Ophthalmologists have the opportunity to play a key role in the early diagnosis and management of this potentially fatal disease.

Adult↗
PubMed2006

Esterified estrogens combined with methyltestosterone raise intraocular pressure in postmenopausal women.

PURPOSE: To investigate the effect of esterified estrogens combined with methyltestosterone (EECM) (Estratest, Solvay, Pharmaceuticals, Inc, Baudette, Minnesota, USA) on intraocular pressure (IOP) in postmenopausal women. DESIGN: Observational case series. METHODS: The IOP of 13 consecutive postmenopausal women with dry eye syndrome were recorded before and during EECM therapy (1.25 mg of esterified estrogens and 2.5 mg of methyltestosterone for several months). RESULTS: The mean IOP increased from a baseline of 15.0 mm Hg before treatment to 18.2 mm Hg on EECM therapy (P < .0001) after a median duration of 11.3 months (range, 0.9 to 24 months). The increase in IOP was statistically significant at the 0.05 level of significance within three months and continued over 12 months. Two patients whose pressures increased (>4 mm Hg) returned to baseline levels after EECM was discontinued. CONCLUSIONS: Esterified estrogens combined with methyltestosterone produce a clinically significant increase in IOP in postmenopausal women with dry eye syndrome.

Aged↗
PubMed2006

Optical coherence tomography to assess intrastromal corneal ring segment depth in keratoconic eyes.

PURPOSE: To investigate intrastromal corneal ring segment depth with a high-speed corneal optical coherence tomography (OCT) system. SETTING: Doheny Eye Institute, University of Southern California, Los Angeles, California, USA. METHODS: A prospective observational case series comprised 4 eyes of 4 patients receiving Intacs intrastromal corneal ring segments (Addition Technology, Inc.) for keratoconus. Optical coherence tomography (OCT) was performed between 7 days and 43 days after implantation. RESULTS: The slitlamp impression of intrastromal corneal ring segment implantation depth did not correlate well with OCT measurements (r(2) = 0.68). The fractional implantation depth was correlated with several surgical variables using a stepwise multivariate regression model, and 2 statistically significant correlations were found. The position of the distal portions of the ring segments was shallower than that of the portion closer to the insertion site (P = .003). Segments placed in the inferior cornea (P = .008) experienced more distal shallowing. Shallower depth was associated with greater fractional anterior stromal compression (P = .04). CONCLUSIONS: Shallower placement of intrastromal corneal ring segments may result in more complications, such as epithelial-stromal breakdown and extrusion, because of the greater anterior stromal tensile strain. The distal and inferior portions of intrastromal corneal ring segments tended to be placed at a shallower depth. Optical coherence tomography provided precise measurement of ring segment depth and may help identify implants that pose a greater risk for depth-related complications.

Adult↗
PubMed2005

Intravenous foscarnet in the management of acyclovir-resistant herpes simplex virus type 2 in acute retinal necrosis in children.

BACKGROUND: Diagnosis and management of Acute Retinal Necrosis (ARN) in children that does not respond to systemic acyclovir treatment can be challenging. We report two cases of ARN secondary to herpes simplex virus (HSV) type 2 that was resistant to acyclovir but was treated successfully with intravenous foscarnet. CASE REPORT: Two children diagnosed with ARN failed to show clinical response to systemic acyclovir treatment. Both cases had histories of previous HSV infections and vitreous taps positive for HSV-2. Both were converted to systemic foscarnet treatment with successful control of the retinitis and satisfactory visual outcomes. CONCLUSIONS: Systemic foscarnet can be effective in the management of pediatric acute retinal necrosis caused by HSV-2 when there is an atypical response to conventional acyclovir treatment.

Acyclovir↗
PubMed2005

Atypical presentation of multiple evanescent white dot syndrome involving granular lesions of varying size.

PURPOSE: To report an atypical presentation of multiple evanescent white dot syndrome (MEWDS). DESIGN: Observational case report. METHODS: Review of the clinical, laboratory, photographic, and angiographic records of a patient with MEWDS. RESULTS: A 29-year-old woman presented with 20/400 vision in the right eye associated with multiple, granular lesions of varying sizes (100-1000 microm) in the outer retina, a prominent panuveitis, diffuse choroidal thickening and enlarged blindspot. The multiple lesions and visual disturbances resolved within 4 weeks with corticosteroid treatment, and the patient was diagnosed with MEWDS. CONCLUSIONS: Clinicians should be aware of atypical manifestations of MEWDS. The patient's unusual fundoscopic changes and prominent intraocular inflammatory reaction are findings that have not been reported in patients with MEWDS.

Adult↗
PubMed2005

Rapid recurrence of geographic atrophy after full macular translocation for nonexudative age-related macular degeneration.

OBJECTIVE: To report the recurrence of geographic atrophy (GA) in a patient with nonexudative age-related macular degeneration (AMD) after full macular translocation. DESIGN: Observational case report. METHODS: Review of the clinical, photographic, and angiographic records of a patient with GA who underwent full macular translocation. MAIN OUTCOME MEASURES: Progression of GA. RESULTS: A 73-year-old man with GA secondary to nonexudative AMD underwent a macular translocation with 360 peripheral retinectomy (MT 360) in his left eye. On postoperative month 4, fundus photography showed subtle alterations of the pigment underneath the translocated foveal region. On postoperative month 9, the visual acuity worsened to preoperative levels and there was frank retinal pigment epithelium atrophy involving the new macular region. CONCLUSIONS: The rapid recurrence and development of GA in the translocated fovea after MT 360 raise new questions regarding the pathogenesis of GA. They also raise concerns regarding the use of MT 360 in the management of nonexudative AMD.

Aged↗
PubMed2005

Subfoveal nodule in Coats' disease.

An atypical presentation of Coats' disease is reported with a prominent subfoveal nodule with peripheral retinal exudates. A 6-year old boy presented with 6/120 vision in the left eye associated with an elevated 1 mm subfoveal, circular lesion with peripheral exudates. The fluorescein angiogram showed peripheral retinal telangiectasias with leakage consistent with Coats' disease. The prominent subfoveal nodule is an uncommon initial presentation of Coats' disease and physicians should be aware of this atypical finding.

Child↗
PubMed2004

Postoperative rhabdomyolysis following laparoscopic gastric bypass in the morbidly obese.

HYPOTHESIS: Laparoscopic approaches for weight reduction in the morbidly obese have become common with more than 50,000 bariatric surgical procedures being performed in 2001. The objective of this article is to raise awareness among surgeons of a new complication of rhabdomyolysis from this frequent procedure. DESIGN: Case series extracted from surgical database from January 2, 2001, through December 31, 2002. PATIENTS AND METHODS: We identified 5 cases of postoperative rhabdomyolysis in morbidly obese patients who underwent laparoscopic duodenal switch procedures with parietal gastrectomy. The cause, pathogenesis, and clinical features are reviewed and discussed. RESULTS: Postoperative rhabdomyolysis developed in 5 of 353 morbidly obese patients who underwent consecutive laparoscopic duodenal switch procedures, an incidence of 1.4%. All 5 patients were male, had a mean peak serum creatine kinase level of 19 680 U/L, and reported muscle pain in either the buttock, hip, or shoulder regions during the early postoperative period. CONCLUSIONS: We hypothesized that morbidly obese patients develop critical surface and deep tissue pressures during bariatric surgery, increasing their risk for tissue injury and rhabdomyolysis. Unexplained elevations in the serum creatinine level or reports of buttock, hip, or shoulder pain in the postoperative period should raise the possibility of rhabdomyolysis and prompt clinical investigation. We recommend routine preoperative and postoperative measurements of the serum creatine kinase and serum creatinine levels to aid detection. Surgeons need to keep a low index of suspicion because early diagnosis and treatment are the cornerstones of successful management of rhabdomyolysis.

Acute Kidney Injury↗
PubMed2004

Bartonella henselae infection presenting as a unilateral panuveitis simulating Vogt-Koyanagi-Harada syndrome.

PURPOSE: To report an unusual ocular manifestation of cat scratch disease. DESIGN: Observational case report. METHODS: Review of the clinical, laboratory, photographic, and angiographic records of a patient with cat scratch disease. RESULTS: A 54-year-old woman presented with counting fingers visual acuity in the right eye associated with optic disk edema, diffuse choroidal thickening, and panuveitis. Fluorescein angiography showed disk leakage and hyperfluorescent spots with late leakage suggestive of Vogt-Koyanagi-Harada disease. She was diagnosed with cat scratch disease by serum antibody titers and clinical course. CONCLUSIONS: Ocular manifestations of cat scratch disease can include diffuse thickening of the choroid. Cat scratch disease may manifest with angiographic features suggestive of Vogt-Koyanagi-Harada disease.

Anti-Bacterial Agents↗
PubMed2004

Severe intravascular hemolysis following mitral valve repair.

We report two cases of severe intravascular hemolysis (IVH) following mitral valve repair using a Cosgrove-Edwards ring. In both cases, the degree of mitral regurgitation (MR) seen postoperatively worsened significantly compared to intraoperative transesophageal echocardiogram. Both patients required reoperation with mitral valve replacement with immediate resolution of the hemolysis. We hypothesize that the mitral regurgitation in the setting of an inadequate mitral valve repair is responsible for the hemolysis and propose various mechanisms to explain this pathophysiology. Although IVH remains a rare complication following mitral valve repair, possible screening recommendations should be considered for early detection and treatment given the growing number of mitral valve repairs being performed.

Acute Disease↗
PubMed2003

The role of protein kinase C in modulation of aqueous humor outflow facility.

The elevated intraocular pressure that is commonly associated with glaucoma is believed to arise due to impairment of trabecular meshwork (TM) function. Although the TM and Schlemm's canal (SC) comprise the major route for aqueous humor outflow, little is known about the potential signaling mechanisms involved in the regulation of aqueous outflow. Based on knowledge regarding the role of protein kinase C (PKC) in vascular biology, we sought to understand the contribution of the PKC pathway towards outflow function by studying the modulation of contractile and morphological characteristics of TM and SC cells. We investigated the involvement of PKC in regulation of myosin light chain (MLC) phosphorylation, formation of actin stress fibers and integrin-ECM adhesions (focal adhesions) in human TM and SC cells and correlated these changes with aqueous outflow facility measured in an enucleated porcine whole eye perfusion model. Expression and distribution of PKC isoforms (alpha and epsilon ) in TM and SC cells and tissues was confirmed by Western blot and immunohistochemical analysis, respectively. Both, pharmacological activators (phorbol-12-myristate 13-acetate (PMA) and phorbol-12,13-dibutyrate (PDBu)) and inhibitors (staurosporine and GF109203X) of PKC were found to induce changes in cell shape (retraction and rounding up) and cytoskeletal organization in human TM and SC cells. While PMA and PDBu produced an increase in formation of actin stress fibers and focal adhesions and in MLC phosphorylation, PKC inhibitors were observed to induce contrasting effects in these cells. Intriguingly, both PDBU and GF109203X caused increases in aqueous outflow facility in the perfusion model. The PKC inhibitor (GF109203X) increased outflow by 46% while the PKC activator (PDBu) only increased outflow by 27%. These results suggest that PKC might play an important role in modulation of aqueous outflow facility by regulating MLC phosphorylation and thereby, the morphological and cytoskeletal characteristics of TM and SC cells.

Actins↗
PubMed2003

Readability of ocular medication inserts.

OBJECTIVE: To determine the readability of ocular medication inserts and whether they are an appropriate source of medication information for patients. MATERIALS AND METHODS: The Flesch-Kincaid and SMOG readability formulas were used to calculate the readability of 10 common glaucoma medication inserts (Alphagan, Azopt, Betoptic, Betimolol, Cosopt, Optipranolol, Rescula, Trusopt, Timoptic, and Xalatan) and 6 widely used nonglaucoma medication inserts (Alrex, Lotemax, Ocuflox, Patanol, Pred Forte, and Zaditor). RESULTS: The 10 glaucoma medication inserts surveyed required an average overall grade level of 12.9 +/- 0.6 by the Flesch-Kincaid Index and of 13.5 +/- 0.6 by the SMOG formula. The 6 nonglaucoma medication inserts had an overall grade level of 11.1 +/- 0.6 by the Flesch-Kincaid Index and of 11.7 +/- 0.9 by the SMOG formula. All medications reviewed were above the eighth-grade level recommended by the Flesch-Kincaid Index for public materials. CONCLUSIONS: Ocular medication inserts are too complex to be an adequate source of medication information for the average American adult. This study highlights the need for improving communication and education regarding patients' medications.

Antihypertensive Agents↗
PubMed2002

Inhibition of Rho-kinase induces alphaB-crystallin expression in lens epithelial cells.

The small heat shock protein, alphaB-crystallin, has been shown to interact with actin and intermediate filament proteins. However, little is known regarding the cellular mechanisms regulating such interactions. In this study, we explored the role of the Rho/Rho-kinase pathway in alphaB-crystallin distribution and expression in porcine lens epithelial cells. alphaB-crystallin was distributed uniformly throughout the cytoplasm and did not exhibit any unique redistribution in response to actin depolymerization induced by Rho/Rho-kinase inhibitors (C3-exoenzyme or Y-27632) or by overexpression of the dominant negative mutant of Rho-kinase (DNRK) in porcine lens epithelial cells. Interestingly, alphaB-crystallin levels markedly increased in lens epithelial cells treated with the inhibitors of Rho/Rho-kinase proteins (lovastatin, Y-27632 or DNRK) while a protein kinase C inhibitor (GF109203x) was found to have no effect. Further, Y-27632 showed a dose (2-50 microM) response effect on alphaB-crystallin induction. Nocodazole, a microtubule-depolymerizing agent, elicited an increase in alphaB-crystallin levels but latrunculin, an actin depolymerizing agent, did not show any significant effect. Pretreatment with cycloheximide or genistein blocked the Rho-kinase inhibitor-induced increase in alphaB-crystallin protein levels. Rho-kinase inhibitor-induced increases in alphaB-crystallin levels were found to be associated with activation of P38 mitogen-activated protein kinase (MAPK). These results suggest that Rho/Rho-kinase negatively regulates alphaB-crystallin expression, and this response appears to be dependent on tyrosine-protein kinase and P38 MAPK function. Finally, alphaB-crystallin induction appears to be better correlated with the direct inhibition of Rho/Rho-kinase than with actin depolymerization per se.

ADP Ribose Transferases↗