Mutational analysis of a conserved positive charge in the c-ring of E. coli ATP synthase

F1Fo ATP synthase is a ubiquitous molecular motor that utilizes a rotary mechanism to synthesize adenosine triphosphate (ATP), the fundamental energy currency of life. The membrane-embedded Fo motor converts the electrochemical gradient of protons into rotation, which is then used to drive the conformational changes in the soluble F1 motor that catalyze ATP synthesis. In E. coli, the Fo motor is composed of a c10 ring (rotor) alongside subunit a (stator), which together provide two aqueous half channels that facilitate proton translocation. Previous work has suggested that Arg50 and Thr51 on the cytoplasmic side of each subunit c are involved in the proton translocation process, and positive charge is conserved in this region of subunit c. To further investigate the role of these residues and the chemical requirements for activity at these positions, we generated 13 substitution mutants and assayed their in vitro ATP synthesis, H+ pumping, and passive H+ permeability activities, as well as the ability of mutants to carry out oxidative phosphorylation in vivo. While polar and hydrophobic mutations were generally tolerated in either position, introduction of negative charge or removal of polarity caused a substantial defect. We discuss the possible effects of altered electrostatics on the interaction between the rotor and stator, water structure in the aqueous channel, and interaction of the rotor with cardiolipin.

Ocular Morbidity among Children of Government Schools of Kathmandu Valley: A Follow-up Study

INTRODUCTION

Ocular and vision defects are common among school going children. Vision disorders, especially refractive errors are the main disabilities of children and the leading cause of handicapping conditions of childhood. The present study was conducted to find out ocular morbidity among students of government schools of Kathmandu valley.

METHODS

In the descriptive and cross-sectional study, 2412 students, comprising of 1114 (46.2%) males and 1298 (53.8%) females were enrolled in to the study from the five government schools of Kathmandu valley from 2012 to 2013. Detailed eye examination included distance visual acuity testing, anterior and posterior segment examinations, retinoscopy and refraction, cover test, near point of convergence, amplitude of accommodation and color vision test. The Chi-square test was performed to analyze the association between ocular morbidity, age and sex. P value was considered significant at 0.05 for 95% confidence interval.

RESULTS

Majority of children were age group between 11 and 13 years (n= 783, 32.5%). A male to female ratio was 0.85. Presenting and best spectacle corrected visual acuity of 6/6 was present in 2257 (93.6%) and 2380 (98.7%) respectively. Total ocular morbidity was observed in 515 (21.4%) subjects. The most common types of ocular morbidity were refractive error in 241 (10%), conjunctivitis in 104 (4.3%) and convergence insufficiency in 82 (3.4%).

CONCLUSIONS

Refractive error, conjunctivitis and convergence insufficiency represent the most common ocular morbidities among students of government schools.

Cold Pressor Test in Borderline Hypertensive University Students

Background Hyperactive sympathetic reaction is an important factor for development of hypertension in young individuals. The stress induced increase in blood pressure recovers within very short period of time and those with exaggerated stress induced cardiovascular response at young age have a high risk of blood pressure elevation in future. Objective To determine the cardiovascular reactivity in response to cold and to correlate its relation with factors such as smoking, family history and physical activity. Method Study was conducted in the Department of Pharmacy, Kathmandu University from July to November, 2015. Resting blood pressure was recorded using sphygmomanometer in sitting position after 5 minutes of rest. Out of 130 volunteers, 34 were found to be prehypertensive and equal number of normotensive were recruited randomly to perform the test. The subjects were directed to immerse his/her right hand up to the wrist in cold water of 10˚C for 1 minute. The blood pressure was recorded just before the hand was taken out of the water and then 1.5 minutes and 4 minutes after the withdrawal. Data was analyzed by Student's t test using Microsoft Excel 2007. Result Systolic and diastolic blood pressure increased significantly after cold pressor test in both normal (systolic blood pressure from 110±6.46 to 119±9.45 mmHg and diastolic blood pressure from 71±4.63 to 78±6.15 mmHg) and prehypertensive group (systolic blood pressure from 122±6.75 to 126±8.05 mmHg and diastolic blood pressure from 79±6.78 to 85±7.76 mmHg). Maximum recovery in both systolic and diastolic blood pressure was observed in 2.5 minutes of removal of hand from cold water. Though sharp drop was observed in blood pressure at the end of 2.5 minute in both groups of individuals, the recovery in case of prehypertensive individual was not sharper. In the present study, significant rise in diastolic blood pressure was observed in prehypertensive smoking males. Also the difference was significant (p<0.02) in recovery of diastolic blood pressure between smoker and non smoker prehypertensive group. Conclusion This study suggests that prolonged elevation in blood pressure in response to stress in young individual can be used as marker of development of hypertension in future. Adopting a healthier lifestyle can help to delay the development of hypertension in later life.

Dynamics of an Active-Site Flap Contributes to Catalysis in a JAMM Family Metallo Deubiquitinase

The endosome-associated deubiquitinase (DUB) AMSH is a member of the JAMM family of zinc-dependent metallo isopeptidases with high selectivity for Lys63-linked polyubiquitin chains, which play a key role in endosomal-lysosomal sorting of activated cell surface receptors. The catalytic domain of the enzyme features a flexible flap near the active site that opens and closes during its catalytic cycle. Structural analysis of its homologues, AMSH-LP (AMSH-like protein) and the fission yeast counterpart, Sst2, suggests that a conserved Phe residue in the flap may be critical for substrate binding and/or catalysis. To gain insight into the contribution of this flap in substrate recognition and catalysis, we generated mutants of Sst2 and characterized them using a combination of enzyme kinetics, X-ray crystallography, molecular dynamics simulations, and isothermal titration calorimetry (ITC). Our analysis shows that the Phe residue in the flap contributes key interactions during the rate-limiting step but not to substrate binding, since mutants of Phe403 exhibit a defect only in kcat but not in KM. Moreover, ITC studies show Phe403 mutants have similar KD for ubiquitin compared to the wild-type enzyme. The X-ray structures of both Phe403Ala and the Phe403Trp, in both the free and ubiquitin bound form, reveal no appreciable structural change that might impair substrate or alter product binding. We observed that the side chain of the Trp residue is oriented identically with respect to the isopeptide moiety of the substrate as the Phe residue in the wild-type enzyme, so the loss of activity seen in this mutant cannot be explained by the absence of a group with the ability to provide van der Waals interactions that facilitate the hyrdolysis of the Lys63-linked diubiquitin. Molecular dynamics simulations indicate that the flap in the Trp mutant is quite flexible, allowing almost free rotation of the indole side chain. Therefore, it is possible that these different dynamic properties of the flap in the Trp mutant, compared to the wild-type enzyme, manifest as a defect in interactions that facilitate the rate-limiting step. Consistent with this notion, the Trp mutant was able to cleave Lys48-linked and Lys11-linked diubiquitin better than the wild-type enzyme, indicating altered mobility and hence reduced selectivity.

Assessment of Color Vision Among School Children: A Comparative Study Between The Ishihara Test and The Farnsworth D-15 Test

INTRODUCTION

Color vision is one of the important attribute of visual perception. The study was conducted at different schools of Kathmandu to compare the findings of the Ishihara Pseudoisochromatic test and the Farnsworth D-15 test.

METHOD

A cross-sectional study was conducted among 2120 students of four schools of Kathmandu. Assessment included visual acuity measurement, slit lamp examination of anterior segment and fundus examination with direct ophthalmoscopy. Each student was assessed with the Ishihara pseudoisochromatic test and the Farnsworth D-15 test. The Chi-square test was performed to analyse color vision defect detected by the Ishihara test and the Farnsworth D-15 test.

RESULTS

A total of 2120 students comprising of 1114 males (52.5%) and 1006 females (47.5%) were recruited in the study with mean age of 12.2 years (SD 2.3 years). The prevalence of color vision defect as indicated by the Ishihara was 2.6 and as indicated by the D-15 test was 2.15 in males.

CONCLUSION

For school color vision screening, the Ishihara color test and the Farnsworth D-15 test have equal capacity to detect congenital color vision defect and they complement each other.

Intercalating dyes for enhanced contrast in second-harmonic generation imaging of protein crystals

The second-harmonic generation (SHG) activity of protein crystals was found to be enhanced by up to ∼1000-fold by the intercalation of SHG phores within the crystal lattice. Unlike the intercalation of fluorophores, the SHG phores produced no significant background SHG from solvated dye or from dye intercalated into amorphous aggregates. The polarization-dependent SHG is consistent with the chromophores adopting the symmetry of the crystal lattice. In addition, the degree of enhancement for different symmetries of dyes is consistent with theoretical predictions based on the molecular nonlinear optical response. Kinetics studies indicate that intercalation arises over a timeframe of several minutes in lysozyme, with detectable enhancements within seconds. These results provide a potential means to increase the overall diversity of protein crystals and crystal sizes amenable to characterization by SHG microscopy.

Retrospective study of spinal cord injury patients admitted to spinal injury rehabilitation center, Sanga, Banepa, Nepal

Spinal cord injury is a serious problem that affects many facets of an individual's life. This was a retrospective study which included data from all patients admitted to the Spinal Injury Rehabilitation Center (SIRC), Sanga with spinal injuries over a 4 year period between January 2008 and January 2011. The overall objective of the study was to determine the epidemiology of spinal injury patients admitted at the center. Socio-demographic details, mechanism of injury, level of injury, ASIA score and length of hospital stay of the subjects were recorded and analyzed. An incremental pattern was observed in the number of spinal injury patients attending SIRC. In the year 2008, 81 patients of spinal injury were recorded which increased to 122 in 2011. A total of 381 spinal injury patients were included in the study out of which a majority, 73.50% were male, 30.45% belonged to the 21-30 years age group and 23.10% belonged to the 31-40 years age group. A majority of Spinal injury patients, 189 (49.60%), were from the Central region followed by 89 (23.36%) from the Western region. Fall from height (68.24%) was the predominant cause of spinal injury followed by road traffic accident (18.63%). In the study, 213 subjects (55.91%) had ASIA A scoring and thoracic injury (49.34%) was most common followed by lumbar injury (29.66%), cervical injury (17.84%) and sacral injury (3.15%). About Two-fifths (40.42%) of the spinal injury patients were conservatively managed whereas three-fifths (59.58%) underwent surgery and length of stay of patients ranged from 2 to 305 days. This study shows that the young adults, predominantly males in their most productive years of life, are prone to traumatic spinal cord injury which results in personal and family tragedies along with socioeconomic burden to the nation. Thus, recognizing the pattern of traumatic spinal cord injuries, relevant etiological factors and identification of high-risk groups is necessary in designing better methods of prevention.

Insights into the mechanism of deubiquitination by JAMM deubiquitinases from cocrystal structures of the enzyme with the substrate and product

AMSH, a conserved zinc metallo deubiquitinase, controls downregulation and degradation of cell-surface receptors mediated by the endosomal sorting complexes required for transport (ESCRT) machinery. It displays high specificity toward the Lys63-linked polyubiquitin chain, which is used as a signal for ESCRT-mediated endosomal–lysosomal sorting of receptors. Herein, we report the crystal structures of the catalytic domain of AMSH orthologue Sst2 from fission yeast, its ubiquitin (product)-bound form, and its Lys63-linked diubiquitin (substrate)-bound form at 1.45, 1.7, and 2.3 Å, respectively. The structures reveal that the P-side product fragment maintains nearly all the contacts with the enzyme as seen with the P portion (distal ubiquitin) of the Lys63-linked diubiquitin substrate, with additional coordination of the Gly76 carboxylate group of the product with the active-site Zn²⁺. One of the product-bound structures described herein is the result of an attempt to cocrystallize the diubiquitin substrate bound to an active site mutant presumed to render the enzyme inactive, instead yielding a cocrystal structure of the enzyme bound to the P-side ubiquitin fragment of the substrate (distal ubiquitin). This fragment was generated in situ from the residual activity of the mutant enzyme. In this structure, the catalytic water is seen placed between the active-site Zn²⁺ and the carboxylate group of Gly76 of ubiquitin, providing what appears to be a snapshot of the active site when the product is about to depart. Comparison of this structure with that of the substrate-bound form suggests the importance of dynamics of a flexible flap near the active site in catalysis. The crystal structure of the Thr319Ile mutant of the catalytic domain of Sst2 provides insight into structural basis of microcephaly capillary malformation syndrome. Isothermal titration calorimetry yields a dissociation constant (K_D) of 10.2 ± 0.6 μM for the binding of ubiquitin to the enzyme, a value comparable to the K_M of the enzyme catalyzing hydrolysis of the Lys63-linked diubiquitin substrate (∼20 μM). These results, together with the previously reported observation that the intracellular concentration of free ubiquitin (∼20 μM) exceeds that of Lys63-linked polyubiquitin chains, imply that the free, cytosolic form of the enzyme remains inhibited by being tightly bound to free ubiquitin. We propose that when AMSH associates with endosomes, inhibition would be relieved because of ubiquitin binding domains present on its endosomal binding partners that would shift the balance toward better recognition of polyubiquitin chains via the avidity effect.

Dynamical tunneling of a Bose-Einstein condensate in periodically driven systems

We report measurements of dynamical tunneling rates of a Bose-Einstein condensate across a barrier in classical phase space. The atoms are initially prepared in quantum states that extend over a classically regular island region. We focus on the specific system of quantum accelerator modes of the kicked rotor in the presence of gravity. Our experimental data is supported by numerical simulations taking into account imperfections mainly from spontaneous emission. Furthermore, we predict experimentally accessible parameter ranges over which direct tunneling could be readily observed if spontaneous emission was further suppressed. Altogether, we provide a proof-of-principle for the experimental accessibility of dynamical tunneling rates in periodically driven systems.

Quality of life among HIV positive individuals in Kathmandu valley and Eastern region of Nepal

BACKGROUND

The alarming increase of HIV/AIDS, inability to afford highly active anti-retroviral therapy, disability and stigma associated with the disease, loss of productivity due to illness, and chronic nature of the disease has made HIV/AIDS one of the most important public health problems in developing countries. The Quality of life assessment is focused on humanistic element and intervention resulting from this result may lead to better overall patient well being.

OBJECTIVE

The aim of our study was to assess and compare the quality of life among HIV positive individuals in Kathmandu Valley and Eastern region.

METHODS

The study was conducted among 228 HIV positive individuals from Eastern Nepal and 213 from Kathmandu valley and they were compared with an equal number of age-sex matched controls from the community. The instrument used was the WHO QOL-BREF Nepali questionnaire.

RESULTS

The HIV positive individuals had significantly lower (P<0.001) QOL scores than the controls in the overall QOL and all the domains of life: Physical, Psychological, Social and Environmental. HIV positive individuals from Kathmandu valley scored significantly better (P<0.001) scores in the Physical and Environmental domains when compared to HIV positive individuals from Eastern region. HIV positive females had a significantly higher (P<0.02) QOL scores for overall QOL and overall perception of health than the males.

CONCLUSION

These findings suggest that HIV positive individuals have a poorer quality of life than the general population in Kathmandu valley and Eastern region of Nepal and interventions could be targeted to improve this aspect of their health.

Bacteriological study of neonatal sepsis and antibiotic susceptibility pattern of isolates in Kathmandu, Nepal

Bloodstream infections in neonates are life-threatening emergencies. Identification of the common bacteria causing such infections and their susceptibility patterns will provide necessary information for timely intervention. This study was done to determine the prevalence of neonatal septicaemia, identify the bacterial isolates and study their antimicrobial susceptibility pattern in neonates admitted to the neonatal intensive care unit of Nepal Medical College Teaching Hospital (NMCTH), Kathmandu, Nepal. This descriptive-analytical study was conducted in NMCTH from July 2011 to January 2012. Blood culture of all neonates who were suspected for neonatal sepsis was performed. Bacterial isolation, identification and antimicrobial susceptibility testing were done by standard microbiological method. Out of 120 neonates suspected of having neonatal sepsis, 30.8% (37/120) were blood culture positive (i.e. prevalence = 30.8%). The most common causative agents of neonatal sepsis was Staphylococcus aureus (56.8%; 21/37) followed by Klebsiella pneumoniae (21.7%; 8/37), Pseudomonas aeruginosa (13.4%; 5/37) and others. Neonatal sepsis was more frequent in male neonates (32.5%) while (26.5%) in female neonates in the ratio of 1.2:1 (p > 0.05). Neonatal sepsis was significantly higher (58.3%) in low birth weight (LBW) (< 2.5kg) neonates compared with good birth weight (GBW) (23.9%) (< 0.05). Prevalence was higher in preterm neonates (57.8%; 11/19) as compared with term-babies (25.7%) (P = 0.05). Generally, all of the isolates were sensitive to most of the antibiotics used as the first line drugs like amikacin, gentamicin, cefotaxime and ampicillin except Acinetobacter baumannii. This organisms was only sensitive towards cotrimoxazole, azithromicin, cefotaxime and ceftazidime.

Fidelity of the quantum δ-kicked accelerator

The sensitivity of the fidelity in the kicked rotor to an acceleration is experimentally and theoretically investigated. We used a Bose-Einstein condensate exposed to a sequence of pulses from a standing light wave followed by a single reversal pulse in which the standing wave was shifted by half a wavelength. The features of the fidelity "spectrum" as a function of acceleration are presented. This work may find applications in the measurement of temperature of an ultracold atomic sample.

Ocular Morbidity among Children Attending Government and Private Schools of Kathmandu Valley

Introduction: Children from the developing world are more prone to going blind from avoidable and preventable causes. In Nepal, children in private schools are reported to have a higher ocular morbidity than those in government schools, with myopia being the major cause of the morbidity. This study was designed to evaluate ocular morbidity in students from both types of school. Methods: This was a cross-sectional, comparative study among students from government and private schools of Kathmandu. Eye examination was carried out evaluating visual acuity, color vision, refractive status, binocular vision status, and anterior and posterior segment findings. Results: A total of 4,228 students from government and private schools were evaluated. The prevalence of ocular morbidity was 19.56 % with refractive error (11.9 %) being the major cause of the morbidity, followed by strabismus and infective disorders. No signifi cant difference in the prevalence of ocular morbidity and refractive status was found in the students from government and private schools. Conclusions: A signifi cant number of children of school-going age have ocular morbidity with no signifi cant difference in the prevalence in the students from government and private schools. Research exploring the effect of various risk factors in the progression of myopia would be helpful to investigate the refractive status in children from these different types of schools. Keywords: Myopia, ocular morbidity, school Students

Ocular manifestations in diabetes, a hospital based prospective study

Diabetes adversely affects the visual status of elderly persons, lowering their quality of life. Since the incidence of diabetes is increasing in urban Nepal, the present study investigated the ocular status in 128 diabetes patients. The ocular complications of diabetes mellitus are numerous including retinopathy, cataract and others. The ocular evaluations were done including visual acuity, refraction and anterior and posterior segment evaluation. Among 128 diabetes, only 26 patients (20.31%) had some degree of retinopathy; with 13.28% having non proliferative diabetic retinopathy and 7.03% with proliferative diabetes retinopathy.

Ocular morbidity among children attending government and private schools of Kathmandu valley

INTRODUCTION

Children from the developing world are more prone to going blind from avoidable and preventable causes. In Nepal, children in private schools are reported to have a higher ocular morbidity than those in government schools, with myopia being the major cause of the morbidity. This study was designed to evaluate ocular morbidity in students from both types of school.

METHOD

This was a cross-sectional, comparative study among students from government and private schools of Kathmandu. Eye examination was carried out evaluating visual acuity, color vision, refractive status, binocular vision status, and anterior and posterior segment findings.

RESULTS

A total of 4,228 students from government and private schools were evaluated. The prevalence of ocular morbidity was 19.56 % with refractive error (11.9 %) being the major cause of the morbidity, followed by strabismus and infective disorders. No significant difference in the prevalence of ocular morbidity and refractive status was found in the students from government and private schools.

CONCLUSION

A significant number of children of school-going age have ocular morbidity with no significant difference in the prevalence in the students from government and private schools. Research exploring the effect of various risk factors in the progression of myopia would be helpful to investigate the refractive status in children from these different types of schools.

Analysis of the composition of lipid in human meibum from normal infants, children, adolescents, adults, and adults with meibomian gland dysfunction using ¹H-NMR spectroscopy

PURPOSE

This study represents a first step toward the evaluation of possible compositional differences in meibum from normal donors (Mn) and donors with meibomian gland dysfunction (Md) by (1)H-NMR spectroscopy. The results highlight the applicability of (1)H-NMR spectroscopy for the quantitative analysis of waxes, cholesteryl esters, and glycerides in meibum lipid (ML).

METHODS

Meibum was obtained from 41 normal donors and 51 donors with meibomian gland dysfunction (MGD). (1)H-NMR spectroscopy was used to quantify the amount of waxes, glycerides, and cholesteryl esters in human meibum.

RESULTS

The relative amount of cholesteryl esters in Mn increased with age and was 40% (P < 0.05) lower in Md. Interestingly, the relative levels of cholesteryl esters in infant meibum were comparable to those in Md. The relative amounts of glycerides were not affected significantly by age or MGD.

CONCLUSIONS

The changes in cholesteryl ester could be used as a molecular marker for MGD and could potentially be applied to follow the efficacy of drug therapy in the treatment of MGD. The similarity of the levels of cholesteryl esters in infant meibum and Md suggests that the relative amounts of these meibum components alone are unlikely to be responsible for the increased stability of the infant tear film and decreased stability of the tear film with MGD. This study reveals the complexity of human MLs and the changes that occur with age and disease. Understanding the factors that lead to such variations is of utmost relevance in the design of effective therapies.

Pattern of refractive errors among patients at a tertiary hospital in Kathmandu

A hospital based cross sectional study was carried out to determine the pattern of refractive errors among patients attending the out patient department, Department of Ophthalmology, Nepal Medical College Teaching Hospital. A total of 1100 patients were evaluated, (male 43.67%; female 56.33%). Simple myopic astigmatism was the most prevalent type of refractive error accounting for 27.18% followed by simple myopia (21.66%) and compound myopic astigmatism (19.48%). Simple hypermetropia (15.03%) and mixed astigmatism (4.3%) were also noted. Simple myopia was prevalent among the younger age group in the first to third decades, whereas hypermetropia was seen in the older patients in the third to fifth decades.

First case of congenital toxoplasmosis from Nepal

Reportedly, nearly half of the Nepalese are Toxoplasma seropositive. However, neither the prevalence of congenital toxoplasmosis (CT) nor the confirmed case to CT is reported from Nepal yet. In this case report, we report the first case of CT in a 53 days old full term male baby (weight: 2,600 grams) delivered by caesarean section. The baby had hepatosplenomegaly and optic nerve coloboma with large scar in the right eye. The TORCH panel test showed significantly high Toxoplasma IgM antibody level (5.77 OD Ratio) compared with IgM antibody level against other agents. The baby was diagnosed as a case of CT and treatment was started accordingly. The baby, however, did not improve with the treatment and died after six days. The immediate cause of death was cardiorespiratory failure with antecedent cause of liver failure, renal insufficiency with thrombocytopenia.

Color Vision Defects in School Going Children

Introduction: Color Vision defect can be observed in various diseases of optic nerve and retina and also a significant number of people suffer from the inherited condition of red and green color defect.  Methods: A cross-sectional descritptive study was designed with purposive sampling of students from various schools of Kathmandu Valley. All children were subjected to color vision evaluation using Ishihara Isochromatic color plates along with other examination to rule out any other causes of color deficiency.  Results: A total of 2001 students were examined, 1050 male students and 951 females with mean age of 10.35 (±2.75) and 10.54 (±2.72) respectively. Among the total students examined, 2.1% had some form of color vision defects. Of the male population , 3.9% had color vision defects while none of the female was found with the deficiency.  Conclusions: The prelevance of color vision defect in Nepal is significant and comparable with the prelevance quoted in the studies from different countries. Keywords:color vision; congenital red green color effect; Nepal; prevalence.

Color vision defects in school going children

INTRODUCTION

Color vision defect can be observed in various diseases of optic nerve and retina and also a significant number of people suffer from the inherited condition of red and green color defect.

METHODS

A cross-sectional descriptive study was designed with purposive sampling of students from various schools of Kathmandu Valley. All children were subjected to color vision evaluation using Ishihara Isochromatic color plates along with other examination to rule out any other causes for color deficiency.

RESULTS

A total of 2001 students were examined, 1050 male students and 951 females with mean age of 10.35 (+/- 2.75) and 10.54 (+/- 2.72) respectively. Among the total students examined, 2.1% had some form of color vision defects. Of the male population, 3.9% had color vision defects while none of the female was found with the deficiency.

CONCLUSIONS

The prevalence of color vision defect in Nepal is significant and comparable with the prevalence quoted in studies from different countries.

A study of ocular morbidity of patients attending a satellite clinic in Bhaktapur, Nepal

A community based retrospective study was conducted in the satellite clinic of Nepal Medical College Teaching Hospital at Jhaukhel VDC of Bhaktapur, from March 2007 to February 2008. A total of 395 patients were examined, where males comprised of 135 patients (32.9%) and females 265 patients (67.1%). The common ocular diseases observed in this study were refractive errors 22.5%, age related cataract 17.5%, extra ocular diseases like conjunctivitis 14.9%, conjunctival degenerations 10.8%.

Cost-utility of tuberculosis prevention among HIV-infected adults in Kampala, Uganda

SETTING

Treatment of latent tuberculosis (TB) infection using isoniazid preventive therapy (IPT) in a human immunodeficiency virus (HIV) volunteer counseling and testing center in Kampala, Uganda.

OBJECTIVE

To analyze the cost-utility of an IPT program for persons newly diagnosed with HIV.

DESIGN

The cost-utility analysis of the IPT program was conducted using Markov cohort simulation methods. Newly diagnosed HIV-infected persons were evaluated using tuberculin skin test (TST); those with positive TST were offered IPT for 9 months (targeted testing strategy). An alternative strategy of offering IPT to all HIV-infected clients without TST screening was also evaluated (treat all strategy). The cost-utility of targeted testing was compared to the 'no program' and the 'treat all' strategies.

RESULTS

The IPT program with the targeted testing strategy would produce 11 quality-adjusted life-years (QALYs) per 100 HIV-infected clients compared to no program. Offering IPT using the treat all strategy gained an additional 30 QALYs per 100 clients compared to targeted testing. Compared to no program, the incremental cost-utility of the targeted testing program was US$102/QALY gained. The cost-utility of the IPT program under the treat all strategy was US$106/QALY gained compared to the targeted testing strategy.

CONCLUSIONS

The provision of IPT for HIV-infected persons was cost-effective. The use of TST screening prior to IPT reduced costs per QALY gained, but saved fewer overall QALYs.

Cost-effectiveness of including tuberculin skin testing in an IPT program for HIV-infected persons in Uganda

SETTING

Tuberculosis (TB) is the most common opportunistic infection among persons with human immunodeficiency virus or the acquired immune-deficiency syndrome (HIV/AIDS). Isoniazid preventive therapy (IPT) effectively treats latent TB infection (LTBI) and prevents progression to active TB.

OBJECTIVE

To analyse the costs and cost-effectiveness of tuberculin skin testing (TST) prior to offering IPT.

DESIGN

We implemented a program for LTBI screening and IPT using TST for persons with HIV at a voluntary counseling and testing (VCT) center in Kampala, Uganda. Cost-effectiveness analyses using Markov methods were adopted to compare strategies of using and not using TST before offering IPT.

RESULTS

The program enrolled 7073 persons with HIV. Based on the prevalence of LTBI in the population, 34/100 HIV-infected patients would benefit from IPT. The results showed that 28% of LTBI patients would be treated using the TST strategy, and 40% would be treated with a non-TST strategy. Compared to no intervention, the estimated incremental cost of identifying and providing IPT using TST was dollars 211 per patient; the incremental cost using a non-TST strategy was dollars 768 per patient.

CONCLUSION

At a large VCT center in Uganda, the inclusion of TST to identify the HIV-infected persons who will most benefit from IPT is cost-effective.

Association of systemic diseases with retinal vein occlusive disease

Retinal vein occlusion (RVO) is the second commonest vascular disease of the eye, second only to Diabetic Retinopathy. The association of the retinal vein occlusion with other systemic disease likes hypertension, diabetes mellitus and others has been well documented. With the increase in persons being affected from these disorders, patients with retinal vein obstruction are also increasing. Hence, a study was designed to evaluate all cases of RVO to find out its association with systemic disorders. A total of 100 patients (106 eyes) were enrolled in the study. Out of which, 66 cases reported to have Brach Retinal Vein Occlusion (BRVO) and rest 34 cases with Central Retinal Vein Occlusion (CRVO). Among the associated systemic diseases, hypertension and diabetes mellitus accounted for 84% cases. Isolated hypertension (54%) was most commonly seen followed by diabetes mellitus (8%). The prevalence of BRVO was almost twice as compared to CRVO. The high association of various systemic disorder especially Hypertension and diabetes further supports the need of early and periodic eye examination for those suffering from these disorders.

Nitrate pollution in groundwater and strategies to reduce pollution

The input-intensive rainfed tropical ecosystem, where wet season (WS) rice (Oriza sativa L.)-dry season (DS) diversified high-value upland crops like vegetables predominate, has resulted in a problem of a large leakage of N into the environment, thereby polluting the water. Excessive use of N fertilizer in high-value crops grown in DS is economically motivated. Out of twenty water sources evaluated in a watershed with a total area of 265 ha located in Magnuang, Ilocos Norte, Philippines, twelve had near or above the World Health Organization's (WHO) NO3-N limit for drinking water of 10 ppm. Soil mineral N (upper 100 cm) observed in seven rice-sweet pepper (Capsicum annuum L.) farmers' fields ranged from 111 to 694 kg ha(-1) which decreased by 10 to 68% in plots with dry-to-wet (DTW) crops like indigo, indigo+mungo and corn. In fallow plots where mineral N was either maintained or increased, it showed movement to lower soil profiles demonstrating NO3 leaching without a crop. On average, maize (Zea mays L.) captured 176 kg N ha(-1) and indigo (Indigofera tinctoria L.) 194 kg N ha(-1). In both fallow and planted plots, mineral N declined to low levels at 100% water-filled pore spaces (WFPS) before rice transplanting. A strategy for including indigo plus maize as a N-catch crop is proposed to decrease NO3 leaching and maximize N use efficiency in a rice-sweet pepper cropping system.

Head injury in Bir HOspital

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