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Biomedical subjects

R Shenoy

Publications and source records attributed to R Shenoy.

At least 19 recordsLinked to original sources
PubMed2006

[Microbial keratitis: a 4 year study of risk factors and traditional/complementary medicine in Oman].

PURPOSE: To determine the risk factors and the influence of complementary/alternative medicines (CAM) for infectious keratitis in a monsoon-free region of the Sultanate of Oman. STUDY DESIGN: Retrospective single center cohort study. OUTCOME MEASURES: Demographic data, risk factors, and pathogens. METHODS: Patients with purulent stromal keratitis admitted from 2001-2004 were evaluated for clinical and microbiological data, CAM use, duration of hospitalization, and outcome of treatment. STATISTICS: chi(2)-test, Z-test. RESULTS: A total of 320 patients (326 eyes) out of 7,524 admissions had severe infectious stromal keratitis requiring inpatient treatment. The average age was 35.1+/-2.5 years (range 1.5-63 years), the male:female ratio was 2:3 in the age group >or=13 years and 2:1 in the age group <or=12 years. Unsuccessful treatment by traditional healers prior to presentation was recorded for 203 patients (62.3%). Ocular risk factors included severe trachomatous dry eye conditions, meibomianitis and soft contact lens overwear. Systemic compromising risk factors were diabetes mellitus and medical immunosuppression. A total of 215 patient eyes (66%) had delayed or no healing (therapy drop-outs), and hospitalization (45 days) was significantly prolonged compared to the 111 antibiotic responders (26 days) (p<0.001). All eyes of patients with prior CAM had worse vision at admission and after therapy (p<0.001), and 97 eyes of patients with uncontrolled diabetes (p<0.001) and 68 eyes of patients with immunosuppression (p<0.001) had a poor visual outcome (vision <0.1). Thirteen eyes perforated. A negative microbiological result correlated with worse final vision (p<0.05). All 13 perforated eyes had received prior CAM (p<0.001). CONCLUSIONS: Trachoma, trauma and contact lens overwear are significant risk factors for infectious keratitis in Oman and correlate with specific age groups. Delay in treatment due to the first-line utilization of CAM showed a significant adverse impact on outcome.

Adolescent↗
PubMed2006

[Diseases of the adnexa in the tropics: amnion membrane transplantation for noninfectious trachoma-associated corneal ulcers].

BACKGROUND: Corneal ulcers with fornix shortening associated with late stages of cicatrizing trachoma contribute significantly to blindness in many developing countries. We report on the outcome of ocular surface and fornix reconstruction using amnion membrane transplantation. PATIENTS AND METHODS: From 2001 to 2005, cryopreserved human amnion membrane without mitomycin C was grafted to 25 eyes of 17 patients with trophic corneal ulcers and symblepharon (cicatrizing trachoma: 19 eyes of 14 patients, Stevens-Johnson syndrome: 4 eyes of 2 patients, alkali burns: 2 eyes of 1 patient) in a controlled case series. Follow-up was done up to 6 months. STATISTICS: Fischer's exact probability test. RESULTS: Of 25 eyes, 9 of 19 eyes with trachoma, 3 of 4 eyes with Stevens-Johnson syndrome, and 2 of 2 eyes with chemical burns showed complete reepithelialization and stromal recovery after 28-35 days (mean: 31+/-2.3 days). The primary success rate of trachoma eyes was not significantly different from the other indications (p=0.256). At 6 months post-op, 15 of 19 trachoma eyes (79%) compared to 2 of 6 non-trachoma eyes (33.3%) had developed a recurrence of symblephara (p=0.0592), and 13 of 15 eyes (86.6%) with a cicatricial trachoma compared to 1 of 6 with non-trachoma diagnosis experienced a recurrence of corneal vascularization (difference nonsignificant: p=0.1752). Persistent long-term reepithelialization was observed only in 1 of 19 trachoma eyes (5.3%) versus 4 of 6 non-trachoma eyes (66.7%, p=0.005); 3 of 19 trachoma eyes with a recurrence of ulcers had perforated after 6 months. CONCLUSIONS: Human amnion membrane without mitomycin C can be used for ocular surface reconstruction in selected patients with cicatrizing trachoma. Its efficacy in the long-term rehabilitation of cicatrizing trachoma seems to be limited due to the progressive scarring.

Adult↗
PubMed2005

[Patients with secondary open-angle glaucoma in pseudoexfoliation (PEX) syndrome among a population with high prevalence of PEX. Clinical findings and morphological and surgical characteristics].

BACKGROUND: The second most frequent treatable cause of noninfectious blindness in Oman is high-pressure glaucoma. Therefore, in 2002 a study was performed at our department of ophthalmology to evaluate pseudoexfoliation (PEX) in glaucoma patients. METHODS: In a prospective comparative cohort study, of 204 glaucoma eyes, 135 open-angle glaucomas were evaluated by biomicroscopy, papillometry, and electron microscopy and followed up after 6 months. RESULTS: The incidence of PEX glaucomas relative to all glaucomas was 50.9% and to open-angle glaucomas 77%. The IOP level in PEX was higher than in POAG; the CDR, neuroretinal rim zone, and the visual field loss were not significantly different. In 38 of 104 operated PEX glaucoma eyes, the postoperative visual acuity deteriorated although the IOP was controlled. CONCLUSIONS: PEX high-pressure glaucomas account for half of all glaucomas in the eastern region of the Arabian peninsula. Surgical outcomes feature a high percentage of postoperative reduction of vision in the late PEX stage.

Cataract Extraction↗
PubMed2005

[Cataract patients with pseudoexfoliation (PEX) syndrome among a population with high prevalence of PEX. Clinical findings and morphological and surgical characteristics].

BACKGROUND: Cataracts are the most frequent treatable cause of noninfectious blindness in Oman. Therefore, in 2002 a study was performed at our department of ophthalmology to evaluate cataract patients for pseudoexfoliation. METHODS: In a prospective comparative cohort study, 370 age-related cataract eyes out of an evaluable population of 498 cataracts were evaluated by biomicroscopy, confocal corneal analysis, and electron microscopy and followed up after 6 months. RESULTS: Of 370 age-related cataracts without glaucomas 171 had PEX. Preoperative manifestations were 89 subluxations, 15 vitreous prolapses, 6 ciliolenticular blocks, and 7 intravitreal dislocations. In 40 Omani cataract eyes without PEX the endothelial cell count was normal compared to the age-matched US norm and corneal thickness was less than Caucasians, but more than Afro-Americans. CONCLUSIONS: This study reports on a high incidence and frequent preoperative complications (68%) of the surgical cataract cases in an Arabic population. The development of serious complications and blindness is related to the duration of the disease and the lack of timely surgery.

Aged↗
PubMed2001

Differential regulation of SR calcium transporters by thyroid hormone in rat atria and ventricles.

Thyroid hormone exerts positive inotropic effects on the heart mediated in part by its regulation of calcium transporter proteins, including sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2), phospholamban (PLB), and Na(+)/Ca(2+) exchanger (NCX). To further understand the potential cardiac chamber-specific effects of thyroid hormone action, we compared the triiodo-L-thyronine (T(3)) responsiveness of calcium transporter proteins in atrial versus ventricular tissues. Rats were rendered hypothyroid by ingestion of propylthiouracil, and a subgroup of animals was treated with T(3) for 7 days (7 microg/day by constant infusion). Atrial and left ventricular (LV) tissue homogenates were analyzed for expression of SERCA2, PLB, and NCX proteins by Western blot analysis. SERCA2 protein significantly decreased by 50% in hypothyroid LV and was normalized by T(3) treatment. In contrast, SERCA2 protein in atria was unaltered in the hypothyroid state. PLB protein expression significantly increased by 1.6- and 5-fold in the hypothyroid LV and atria, respectively, and returned to euthyroid levels with T(3) treatment. Expression of NCX protein showed a greater response to T(3) treatment in atria tissue than in ventricular tissue. Sarcoplasmic reticulum calcium cycling is determined in part by the ratio of SERCA2 to PLB. This ratio was sixfold higher in the atria compared with LV, suggesting that PLB may play a minor role in the regulation of SERCA2 function in normal atria. We conclude that calcium transporter proteins are responsive to thyroid hormone in a chamber-specific manner, with atria showing a greater change in protein content in response to T(3). The differential effect on atria may account for the occurrence of atrial rather than ventricular arrhythmias in response to even mild degrees of thyrotoxicosis.

Animals↗
PubMed2000

Thyroid hormone metabolism and cardiac gene expression after acute myocardial infarction in the rat.

In a rat model of acute myocardial infarction (MI) produced by coronary artery ligation, thyroid hormone metabolism was altered with significant reductions (54%) in serum triiodo-L-thyronine (T(3)), the cellular active hormone metabolite. T(3) has profound effects on the heart; therefore, rats were treated with T(3) after acute MI for 2 or 3 wk, at either replacement or elevated doses, to determine whether cardiac function and gene expression could be normalized. Acute MI resulted in a 50% (P < 0.001) decrease in percent ejection fraction (%EF) with a 32-35% increase (P < 0.01) in compensatory left ventricle (LV) hypertrophy. Treatment of the MI animals with either replacement or elevated doses of T(3) significantly increased %EF to 64 and 73% of control, respectively. Expression levels of several T(3)-responsive genes were altered in the hypertrophied LV after MI, including significant decreases in alpha-myosin heavy chain (MHC), sarcoplasmic reticulum calcium-activated ATPase (SERCA2), and Kv1.5 mRNA, whereas beta-MHC and phospholamban (PLB) mRNA were significantly increased. Normalization of serum T(3) did not restore expression of all T(3)-regulated genes, indicating altered T(3) responsiveness in the postinfarcted myocardium. Although beta-MHC and Kv1.5 mRNA content was returned to control levels, alpha-MHC and SERCA2 were unresponsive to T(3) at replacement doses, and only at higher doses of T(3) was alpha-MHC mRNA returned to control values. The present study showed that acute MI in the rat was associated with a fall in serum T(3) levels, LV dysfunction, and altered expression of T(3)-responsive genes and that T(3) treatment significantly improved cardiac function, with normalization of some, but not all, of the changes in gene expression.

Animals↗
PubMed1999

Regulation of rat cardiac Kv1.5 gene expression by thyroid hormone is rapid and chamber specific.

Thyroid hormone affects the contractile and electrophysiological properties of the cardiac myocyte that result in part from changes in the expression of thyroid hormone-responsive cardiac genes, including those that regulate membrane ion currents. To determine the molecular mechanisms underlying this effect, expression of a voltage-gated K+ channel, Kv1.5, was measured in response to thyroid hormone. Using quantitative RT-PCR methodology, the content of Kv1.5 messenger RNA (mRNA) in left ventricles of euthyroid rats was 4.25+/-0.6x10(-20) mol/microg total RNA and was decreased by 70% in the hypothyroid rat ventricle to 1.27+/-0.80x10(-20) mol/microg RNA (P<0.01). Administration of T3 to hypothyroid animals restored ventricular Kv1.5 mRNA to control levels within 1 h of treatment, making this the most rapid T3-responsive cardiac gene reported to date. The half-life of Kv1.5 mRNA was 1.9 h and 2.0 h in euthyroid and hypothyroid ventricles, respectively, and T3 treatment of the rats did not alter its half-life. In atrial myocardium, expression of Kv1.5 mRNA (6.10+/-0.37x10(-20) mol/microg RNA) was unaltered by thyroid hormone status. The myocyte-specific and chamber-selective expression of Kv1.5 mRNA was confirmed in primary cultures of rat atrial and ventricular myocytes.

Animals↗
PubMed1998

Characterization of determinants for envelope binding and infection in tva, the subgroup A avian sarcoma and leukosis virus receptor.

Tva is the cellular receptor for subgroup A avian leukosis and sarcoma virus (ALSV-A). The viral interaction domain of Tva is determined by a 40-residue, cysteine-rich module closely related to the ligand binding domain of the human low-density lipoprotein receptor (LDLR). In this report, we examined the role of the LDLR-like module of Tva in envelope binding and viral infection by mutational analysis. We found that the entire LDLR module in Tva is essential for efficient binding to the viral envelope protein. However, the 17 N-terminal residues of this module can be deleted without affecting receptor function, suggesting that the major determinants for viral entry are located at the C terminus of the module. The effect on viral infection of many amino acid substitutions and deletions in the LDLR module is context dependent, suggesting that the residues important for viral entry are dispersed throughout the LDLR module. In addition, we found that all 27 mutations at residues D46, E47, and W48 greatly reduced envelope binding. These results are discussed in relation to a recently elucidated structure for an LDLR module.

Amino Acid Sequence↗
PubMed1997

Indications for penetrating keratoplasty in India.

Indications for penetrating keratoplasty (PK) in the developing world from a large series are not well documented. This study was done to evaluate the indications for PK in a major eye care institution in India. The records for a consecutive series of 1,964 PKs were analysed and multiple logistic regression was used to study the effect of age, socioeconomic status and sex on the indications for PK. The indications for PK were corneal scarring in 551 (28.1%) including adherent leukoma in 147 (7.5%), regrafts in 336 (17.1%), active infectious keratitis in 239 (12.2%), aphakic bullous keratopathy in 231 (11.8%), pseudophakic bullous keratopathy in 209 (10.6%), corneal dystrophies in 165 (8.4%) including Fuchs' dystrophy in 23 (1.2%), keratoconus in 118 (6%), and miscellaneous in 115 (5.9%). The odds that the patient belonged to lower socioeconomic status were significantly higher if the PK was done for active infectious keratitis (odds ratio 2.73, p < 0.0001), corneal scarring (odds ratio 1.72, p = 0.0009) or regraft (odds ratio 1.44, p = 0.047). Corneal scarring, including adherent leukoma, and active infectious keratitis are relatively more common indications whereas keratoconus, pseudophakic bullous keratopathy and Fuchs' dystrophy are less common indications for PK in India than reported from the developed world. Indications for PK which carry a poorer prognosis for graft survival are relatively more common in India than in the developed world.

Adolescent↗
PubMed1986

Low 1,25-dihydroxyvitamin D, secondary hyperparathyroidism, and normal osteocalcin in elderly subjects.

The relationship among serum vitamin D metabolites, PTH, and osteocalcin concentrations was investigated in 20 elderly subjects. All except 2 had subnormal 25-hydroxyvitamin D concentrations. Eighteen (90%) had subnormal serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] concentrations, while 8 subjects (40%) had elevated PTH concentrations. There was a highly significant inverse relationship between PTH and 1,25-(OH)2D concentrations. Serum osteocalcin concentrations were not elevated in any subject, and in fact, the mean osteocalcin concentration was in the lower part of the normal range. These data indicate no compensatory increase in 1,25-(OH)2D in response to secondary hyperparathyroidism and no increase in osteocalcin in response to hypersecretion of PTH in the elderly. These 2 defects may contribute to the bone disease of the elderly.

Aged↗