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Tarun Sharma

Publications and source records attributed to Tarun Sharma.

At least 19 recordsLinked to original sources
PubMed2006

Polyhydroxylated homoazepanes and 1-deoxy-homonojirimycin analogues: Synthesis and glycosidase inhibition study.

The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded gamma,delta-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols--immediate precursors for 1-deoxy-homonojirimycin 3a,b, and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitory activity is reported.

1-Deoxynojirimycin↗
PubMed2006

Synthesis of tetrahydroxy perhydroaza-azulenes: tandem Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols.

The Johnson-Claisen rearrangement of D-glucose-derived allylic alcohols 5a,b, afforded sugar-substituted gamma,delta-unsaturated ester in high yield. Conversion of the ester group to an azidomethyl group, epoxidation of the double bond and hydrogenation gave pyrrolidine ring skeletons 13a and 13b, which were transformed to tetrahydroxy perhydroaza-azulenes 1a and 1b, respectively. Glycosidase inhibitory activity was also evaluated.

Journal Article↗
PubMed2006

Synthesis and evaluation of glycosidase inhibitory activity of N-butyl 1-deoxy-D-gluco-homonojirimycin and N-butyl 1-deoxy-L-ido-homonojirimycin.

Conjugate addition of n-butyl amine to d-glucose derived alpha,beta-unsaturated ester 4 afforded beta-amino esters 5a,b that on reduction of ester group, 1,2-acetonide deprotection, and reductive amination led to the formation of corresponding N-butyl 1-deoxy-D-gluco-homonojirimycin 2c and N-butyl 1-deoxy-L-ido-homonojirimycin 2d which were found to be selective beta-glucosidase inhibitors with an IC(50) value in millimolar range.

1-Deoxynojirimycin↗
PubMed2006

Patient satisfaction levels during teleophthalmology consultation in rural South India.

The application of new technologies for analysis of retinal images, neural networks for automated retinopathy grading, and teleophthalmology have been shown to have great value in ophthalmology. India has only one ophthalmic surgeon for every 107,000 population. Given this situation, teleophthalmology can play a vital role in addressing to the eye care needs of the country. The objective of this study was to assess patient satisfaction levels and factors influencing it during teleophthalmology consultation in India. A patient satisfaction questionnaire was prepared to assess the prominent aspects of patient satisfaction, including teleophthalmology screening, confidence in the technology used to transfer the fundus images, comprehensiveness of information available to the doctor in the central hub, and graded the opinion regarding the teleophthalmology. A cross-sectional survey among patients who attended a teleophthalmology screening conducted across eight villages in rural Tamilnadu. Responses were then subjected to qualitative analysis and conclusions made. The number of respondents was 348. Of this, 56.4% were males. The mean age of was 50 +/- 17 years. Age ranged from 2 years to 83 years. 44.4% of the respondents were satisfied with teleophthalmology screening. (95% confidence interval [CI]: 38.58%-49.42%) No association was found between age, gender, education, and occupation, respectively, with satisfaction levels. We found that patients who asked questions during the screening were 2.18 times more likely to be satisfied with teleophthalmology than those who did not (odds ratio [OR] = 2.19, 95% CI 1.37-3.5). This study highlights sentiments of the rural subjects when they underwent teleophthalmology consultations. This study provides valuable insights about patient's preferences and satisfaction levels with this newer technology.

Adult↗
PubMed2006

Refractive issues in pregnancy.

Pregnancy is known to cause refractive changes as a result of various hormonal changes occurring during pregnancy. These changes may persist for a few weeks post-partum and during lactation. In this article we discuss various refractive issues in pregnancy that have an effect on contact lens use, myopia and the outcome of refractive surgery.

Contact Lenses↗
PubMed2006

Diabetic retinopathy in type II diabetics detected by targeted screening versus newly diagnosed in general practice.

INTRODUCTION: The aim of this study was to compare the occurrence of diabetic retinopathy in targeted screening diabetic patients (Group I) with newly diagnosed diabetic patients in general practice (Group II). MATERIALS AND METHODS: This was an observational cross-sectional study. Data were obtained from 25,313 subjects who participated in the diabetic screening camps, and 128 newly diagnosed diabetes who presented to the diabetic retinopathy screening camps in general practice in rural and urban south India. The study variables were collected from all patients who underwent eye examination from the target screening detected diabetics [(n = 173) Group I] and those newly diagnosed in general practice [(n = 128) Group II]. The variations in prevalence of diabetic retinopathy and sight-threatening diabetic retinopathy in Group I and Group II and the factors affecting it were identified. RESULTS: The occurrence of diabetic retinopathy was 6.35% (95% CI, 2.5-9.5) in Group I and 11.71% (95% CI, 5.6-16.4) in Group II. No significant difference was observed on occurrence of diabetic retinopathy, including sightthreatening retinopathy, in rural versus urban population and in Group I versus Group II. Patients diagnosed in general practice (Group II) with systolic blood pressure (BP) >140 were more likely to have retinopathy (P = 0.02). CONCLUSIONS: Diabetic retinopathy including sightthreatening complications was found at the time of diagnosis of diabetes in the targeted screening group as well as in newly diagnosed diabetics in the general practice group.

Adult↗
PubMed2006

Role of ultrasound biomicroscopy (UBM) in the detection and localisation of anterior segment foreign bodies.

INTRODUCTION: The aim of this study was to investigate the role of ultrasound biomicroscopy (UBM) in imaging anterior segment foreign bodies and compare it with conventional B-scan ultrasound and computed tomography (CT). MATERIALS AND METHODS: The charts of 18 eyes with anterior segment foreign bodies were reviewed. The rates of detection of foreign bodies using ultrasound, CT scan and UBM were compared. RESULTS: The foreign body detection rates were 36.5% by ultrasound, 88.9% by CT scan, and 94.4% by UBM. The diagnosis of presence of a foreign body using UBM was made based on high reflective echoes causing shadowing or reverberations. In 7 eyes, UBM detected injury to the zonules, guiding the operative procedure. In the 8 eyes for which all tests were performed, rates of detection of foreign bodies were 25% (2/8) with ultrasound, 87.5% (7/8) with CT, and 100% (8/8) with UBM. CONCLUSION: UBM is a valuable adjunct for the accurate localisation of small foreign bodies, including cilia. It offers a higher detection rate than that provided by ultrasound and CT scan.

Adolescent↗
PubMed2005

Diabetic retinopathy screening model for rural population: awareness and screening methodology.

CONTEXT: Worldwide, the prevalence of diabetic retinopathy is increasing at an alarming rate. WHO has predicted that in India the number of adults with diabetes will be the highest in the world: from 19 million in 1995 to 80 million in 2030. Although originally thought to be a disease of an urban population, the prevalence of diabetes mellitus is increasing in rural areas as well. The socioeconomic burden resulting from visual impairment or blindness caused by diabetic retinopathy, particularly in the working age group, is a serious concern. ISSUE: In order to combat diabetic retinopathy related blindness, Sankara Nethralaya, the premier eye institute of India, in collaboration with the Lions Clubs International Foundation (LCIF) and the RD Tata Trust, Mumbai, India launched a major diabetic retinopathy screening program in the rural community of South India. The objectives were to create awareness among the rural population of diabetic retinopathy with emphasis on early detection, to conduct diabetes and diabetic retinopathy screening camps, and to bring to the base hospital patients who have sight-threatening diabetic retinopathy, for ancillary investigations such as fluorescein angiography, ultrasound and to perform laser photocoagulation or vitreous surgery, or both. Other objectives included training general ophthalmologists and general physicians in order to develop an integrated diabetic retinopathy model. To address the question as to why certain individuals run the risk of developing sight threatening diabetic retinopathy, biochemical and genetic factors were also studied. The program was launched in June 2003 and 3 rural districts have been screened. To the time of writing, 128 screening camps had been organized, 103 awareness meetings conducted, 23 ophthalmologists trained and 43 general physicians attended the continuing medical education program on diabetic retinopathy. LESSONS: The key elements in the successful implementation of this program have been a team approach, involvement of community leaders and voluntary organizations, and support of the district and state administrators.

Adult↗
PubMed2005

Aziridine carboxylate from D-glucose: synthesis of polyhydroxylated piperidine, pyrrolidine alkaloids and study of their glycosidase inhibition.

The D-glucose derived aziridine carboxylate 5 was obtained from (E)-ethyl-6-bromo-1,2-O-isopropylidene-3-O-benzyl-5-deoxy-alpha-D-xylo-5-eno-heptofuranuronate 4 through conjugate addition of benzylamine and in situ intramolecular nucleophilic expulsion of bromine. The regioselective aziridine ring-opening, using water as a nucleophile, resulted in the alpha-hydroxy-beta-aminoester 6, which was exploited in the synthesis of six and five membered azasugars 1b/1c and 2b/2c, respectively. The glycosidase inhibitory activity of the title compounds was evaluated.

Alkaloids↗
PubMed2005

Synthesis and evaluation of the glycosidase inhibitory activity of 5-hydroxy substituted isofagomine analogues.

An efficient strategy for the synthesis of 5-hydroxy substituted isofagomine analogues and , having both -CH2OH/CH3 and -OH functionality at the C-5 position, and evaluation of their inhibitory potency is reported. The synthetic methodology involves the aldol-Cannizzaro reaction of easily available alpha-d-xylopentodialdose followed by hydrogenolysis to afford the triol . Selective amidation of the alpha- and beta-hydroxymethyl group at C-4, deprotection of the 1,2-acetonide group and hydrogenation gave the target molecules, which were found to be potent against beta-glycosidases with IC50 values in the micro molar range. Compound showed excellent potency against glycosidases and human salivary amylase.

Enzyme Inhibitors↗
PubMed2005

1,3-Dipolar cycloaddition reaction of D-glucose-derived nitrone with allyl alcohol: synthesis of 2-hydroxy-1-deoxycastanospermine analogues.

[reaction: see text] The synthesis and evaluation of glycosidase inhibitory activity of polyhydroxylated indolizidine alkaloids namely 2-hydroxy-1-deoxycastanospermine 3a,b and 2-hydroxy-1-deoxy-8a-epi-castanospermine 3c,d is reported. The key step involves the intermolecular 1,3-dipolar cycloaddition of allyl alcohol to d-glucose-derived nitrone 4, followed by tosylation, that afforded four diastereomeric sugar-substituted isoxazolidines 5a-d with the desired regioselectivity. The one-pot conversion of 5a-d to pyrrolidines 8a-d by hydrogenolysis, removal of 1,2-acetonoide functionality, and hydrogenation afforded corresponding target molecules 3a-d.

Glucose↗
PubMed2005

How high is the non-response rate of patients referred for eye examination from diabetic screening camps?

AIM: To elucidate the rate of non-response among diabetics (recently diagnosed in rural diabetic screening camps) who were referred for eye examination to detect diabetic retinopathy. METHODS: At diabetic retinopathy screening camps, all patients underwent dilated fundus examination using binocular indirect ophthalmoscopy. RESULTS: Of the 4,111 known diabetics, only 2231(55%) patients attended the diabetic retinopathy screening camps. Likewise, of the 1076 newly detected diabetics, only 125 (11.6%) attended the diabetic retinopathy screening camps. CONCLUSIONS: Non-response of such a magnitude calls for creating greater awareness among masses on diabetes and its microvascular complications. Second, conducting simultaneous diabetes screening and diabetic retinopathy screening camps could minimize the dropout rate.

Adult↗