First Measurement of the Total Neutron Cross Section on Argon between 100 and 800 MeV

We report the first measurement of the neutron cross section on argon in the energy range of 100-800 MeV. The measurement was obtained with a 4.3-h exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. The total cross section is measured from the attenuation coefficient of the neutron flux as it traverses the liquid argon volume. A set of 2631 candidate interactions is divided in bins of the neutron kinetic energy calculated from time-of-flight measurements. These interactions are reconstructed with custom-made algorithms specifically designed for the data in a time projection chamber the size of the Mini-CAPTAIN detector. The energy averaged cross section is 0.91±0.10(stat)±0.09(syst)  b. A comparison of the measured cross section is made to the GEANT4 and FLUKA event generator packages, where the energy averaged cross sections in this range are 0.60 and 0.68 b, respectively.

Prevalence of White Coat Hypertension among the Patients Visiting in a Tertiary Care Center, Kathmandu, Nepal

Background Hypertension is a major cardiovascular risk factor. White coat hypertension refers to elevated office blood pressure but normal out of office blood pressure. White-coat hypertension has a risk of cardiovascular events more than normotensives. Objective To identify the prevalence of white coat hypertension among patients presented in the cardiology department. Method The descriptive cross-sectional study was conducted among 165 patients who visited the cardiology outpatient department of Kathmandu Medical College and Teaching Hospital from December 2017 to November 2018. Blood pressure was measured at the hospital, and ambulatory blood pressure device was used to monitor 24hrs pattern. Hypertension is classified as per recent guideline. Data were entered and analysed using Statistical Package for social sciences version 20. Result Out of 165 ambulatory blood pressure monitoring conducted patients, 140 participants were enrolled in the study based on inclusion criteria. Among them 55% (77) were male, and 45% (63) were female. Age ranged from 18-78 years with a mean of 43.82 ± 12.31 years. Overall among 140 participants 14.28% had white coat hypertension, however, after excluding twenty-two high normal group, among 118 participants who were hypertensive according to office BP, 16.9% (20) had white coat hypertension, and 33.57% of patients did not have nocturnal dipping of blood pressure. Conclusion The white coat hypertension is prevalent among around one-sixth of hypertensive patients visiting tertiary care centre, and one third have non-dipping which needs to be considered in the management of hypertension.

Self-Perception of Halitosis among Undergraduate Students of Kathmandu University School of Medical Sciences - A Questionnaire Based Study

Background Halitosis is a frequently reported oral health problem worldwide with a prevalence rate of 10-30% in the general population. It is defined as the disagreeable or foul smelling breath originating consistently from a person's oral cavity. It not only effects the normal daily life activities of the patient but also bring humiliation, reduced self- esteem, ultimately resulting into decreased quality of life. Objective To determine the self-perception of halitosis among undergraduate students of different medical branches of Kathmandu University School of Medical Sciences (KUSMS); Kavre, Nepal. Method A descriptive cross-sectional epidemiological survey was conducted among undergraduate students of Physiotherapy, B.Sc Nursing, Bachelor of Nursing Sciences (BNS), MBBS and BDS program of Kathmandu University School of Medical Sciences, Dhulikhel. A self-administered questionnaire was developed and were distributed among 500 undergraduate students. Result Out of total 500 distributed questionnaires, 406 were completely filled and returned giving an overall response of 81.2%, in which 70 (89.7%) male and 280 (85.4%) female students from different medical branches were aware of the term halitosis. Among them 29 (7.14%) of students think that they suffer from halitosis. Similarly 178 (43.84%) students had severe impact of halitosis on their social life while 153 (37.68%) and 62 (15.27%) students had moderate and mild impact respectively. Conclusion Due to the multifactorial complexity of halitosis, further longitudinal studies including objective assessment of malodor are required to determine its prevalence and to further investigate the association of this problem with other etiological factors in the context of Nepal. Also, curriculum of different fields should be modified to include this simple but very necessary topic.

Income Inequality and Use of Dental Services in 66 Countries

This study explored the association between income inequality and use of dental services and the role that investment in health care plays in explaining that association. We pooled individual-level data from 223,299 adults, 18 years or older, in 66 countries, who participated in the World Health Organization (WHO) World Health Surveys with country-level data from different international sources. Income inequality was measured at the national level using the Gini coefficient, and use of dental services was defined as having received treatment to address problems with mouth and/or teeth in the past year. The association between the Gini coefficient and use of dental services was examined in multilevel models controlling for a standard set of individual- and country-level confounders. The individual and joint contributions of 4 indicators of investment in health care were evaluated in sequential modeling. The Gini coefficient and use of dental services were inversely associated after adjustment for confounders. Every 10% increase in the Gini coefficient corresponded with a 15% lower odds of using dental services (odds ratio: 0.85; 95% confidence interval: 0.70-0.99). The association between the Gini coefficient and use of dental services was attenuated and became nonsignificant after individual adjustment for total health expenditure, public expenditure on health, health system responsiveness, or type of dental health system. The 4 indicators together explained 80% of the association between the Gini coefficient and use of dental services. This study suggests that more equal countries have greater use of dental services. It also supports the mediating role of investment in health care in explaining that association.

Epidemiological and Outcome Analysis of Orthopedic Implants Removal in Kathmandu University Hospital

Background Orthopedic Implant removal is one of the commonly performed elective orthopedic surgeries. Implants are generally removed after the purpose of keeping implant is solved by healing of the fracture, but there is no consensus whether routine implant removal should be a policy for all fractures that were fixed. Objective This study aims to analyze the epidemiology and outcome of implant removal surgery carried out in the past three years in Kathmandu University Hospital. Methods Patients who underwent implant removal between 2010 January to 2012 December constituted the study cohort. Demographic data, indications, types of hardware and location of fractures were recorded. Similarly, duration of surgery, type of anesthesia and duration of hospital stay were recorded. All the patients who had undergone implant removal in this three years period were called for follow up examination but those who were not able to come were interviewed on telephone. Results There were 275 implant removals constituting 7.8% of total orthopedic operations and 26.3% of fracture fixations. Male to Female ratio was 189: 86. Pediatric age group (34.5%) had the highest incidence of implant removal. Moderate sized implants were the commonest hardwares removed (63.2%). Femur (27.3%) followed by radius (26.9%) were the commonest bone for implant removal. Average operative time was 47.3 minutes with average hospital inpatient stay of 2.6 days. Commonest indication for the implant removal procedure was pain (45%). Conclusion Implant removal procedures are one of the most commonly performed elective orthopedic surgeries. Though, after orthopedic implants removal, pain relief can be expected but it is not so predictive and hence patient should be well counseled before and the indications for implant removal has to be evaluated for better patient satisfaction and safety. DOI: http://dx.doi.org/10.3126/kumj.v11i2.12489 Kathmandu University Medical Journal Vol.11(2) 2013: 139-143

Global burden of untreated caries: a systematic review and metaregression

We aimed to consolidate all epidemiologic data about untreated caries and subsequently generate internally consistent prevalence and incidence estimates for all countries, 20 age groups, and both sexes for 1990 and 2010. The systematic search of the literature yielded 18,311 unique citations. After screening titles and abstracts, we excluded 10,461 citations as clearly irrelevant to this systematic review, leaving 1,682 for full-text review. Furthermore, 1,373 publications were excluded following the validity assessment. Overall, 192 studies of 1,502,260 children aged 1 to 14 y in 74 countries and 186 studies of 3,265,546 individuals aged 5 y or older in 67 countries were included in separate metaregressions for untreated caries in deciduous and permanent teeth, respectively, using modeling resources from the Global Burden of Disease 2010 study. In 2010, untreated caries in permanent teeth was the most prevalent condition worldwide, affecting 2.4 billion people, and untreated caries in deciduous teeth was the 10th-most prevalent condition, affecting 621 million children worldwide. The global age-standardized prevalence and incidence of untreated caries remained static between 1990 and 2010. There is evidence that the burden of untreated caries is shifting from children to adults, with 3 peaks in prevalence at ages 6, 25, and 70 y. Also, there were considerable variations in prevalence and incidence between regions and countries. Policy makers need to be aware of a predictable increasing burden of untreated caries due to population growth and longevity and a significant decrease in the prevalence of total tooth loss throughout the world from 1990 to 2010.

NADPH oxidase 4 induces cardiac fibrosis and hypertrophy through activating Akt/mTOR and NFκB signaling pathways

BACKGROUND

NADPH oxidase 4 (Nox4) has been implicated in cardiac remodeling, but its precise role in cardiac injury remains controversial. Furthermore, little is known about the downstream effector signaling pathways activated by Nox4-derived reactive oxygen species in the myocardium. We investigated the role of Nox4 and Nox4-associated signaling pathways in the development of cardiac remodeling.

METHODS AND RESULTS

Cardiac-specific human Nox4 transgenic mice (c-hNox4Tg) were generated. Four groups of mice were studied: (1) control mice, littermates that are negative for hNox4 transgene but Cre positive; (2) c-hNox4 Tg mice; (3) angiotensin II (AngII)-infused control mice; and (4) c-hNox4Tg mice infused with AngII. The c-hNox4Tg mice exhibited an ≈10-fold increase in Nox4 protein expression and an 8-fold increase in the production of reactive oxygen species, and manifested cardiac interstitial fibrosis. AngII infusion to control mice increased cardiac Nox4 expression and induced fibrosis and hypertrophy. The Tg mice receiving AngII exhibited more advanced cardiac remodeling and robust elevation in Nox4 expression, indicating that AngII worsens cardiac injury, at least in part by enhancing Nox4 expression. Moreover, hNox4 transgene and AngII infusion induced the expression of cardiac fetal genes and activated the Akt-mTOR and NFκB signaling pathways. Treatment of AngII-infused c-hNox4Tg mice with GKT137831, a Nox4/Nox1 inhibitor, abolished the increase in oxidative stress, suppressed the Akt-mTOR and NFκB signaling pathways, and attenuated cardiac remodeling.

CONCLUSIONS

Upregulation of Nox4 in the myocardium causes cardiac remodeling through activating Akt-mTOR and NFκB signaling pathways. Inhibition of Nox4 has therapeutic potential to treat cardiac remodeling.

Adherence to Antihypertensive Medications: Population Based Follow up in Eastern Nepal

BACKGROUND

Poor adherence toward antihypertensive drugs is a worldwide problem that results in poor health outcomes and increased health care costs. Community based study related to adherence to antihypertensive medication is limited in context of Nepal.

METHODS

This study was conducted to explore the extent of adherence towards prescribed antihypertensive treatment and to identify the factors of non adherence. Community based cross sectional study was conducted in Dharan Municipality of Eastern Region of Nepal from September 2009 to February 2010. Out of 975 hypertensive patients, 154 calculated samples were selected following simple random sampling method. Data was collected by interview method and adherence was measured by using four items Morisky Medicine adherence scale. Data was analyzed using SPSS by descriptive and inferential (Chi square and logistic regression analysis) Statistical method.

RESULTS

Among the 154 hypertensive patients, only 56.5% patients were adherent to antihypertensive medication. The important predictors of non adherence by logistic regression analysis at 95% Confidence Interval were illiteracy (OR 5.34, CI= 1.23 -23 , P=0.025), expensive price of medicine (OR 5.14, CI=1.1-23.9, P=0.037), missed medicine due to cost (OR 0.143,CI=0.02-0.78, P= 0.025), no family history of hypertension (OR 4.46,CI= 1.21-16.4, P=0.024), irregular follow up (OR 6.39,CI=1.22-33.3, P=0.028), more than one pills per day ( OR 5.33,CI=1.19-23.7, P= 0.028).

CONCLUSIONS

Around half of the population was non adherent towards antihypertensive medications so identified gap need to be addressed to increase adherence level.

Performance and economic analyses of year-round forage systems for forage-fed beef production in the Gulf Coast

On a global scale, most beef is produced from grazing pastures or rangelands. Certain limitations exist, however, such as not having adequate animal rates of gain for marbling and availability of adequate forage nutritional value and quantity for constant animal weight gains. In the last 20 yr, there has been an increased interest in forage-fed beef for multiple reasons (health related, environmental concerns, and welfare issues). Starting on June 5, 13, 14, and 8 in 4 consecutive yr, 54 steers (initial BW=259±5.6 kg; average of 9 mo of age) were randomly allotted to 3 yr-round forage systems. Each system occupied 6 ha/replicate and had the same stocking rate. System 1 had annual ryegrass (Lolium multiflorum) for winter grazing and bermudagrass (Cynodon dactylon) for summer grazing; while Systems 2 and 3 added rye and a clover mix to the ryegrass and diversified the use of pastures in the fall (dallisgrass [Paspalum dilatatum] and clovers [Trifolium spp.]). System 3 added the use of annual summer forages. During their respective growing season for each forage or forage mix, mass and height did not limit animal performance; however, there was a sampling date effect (P<0.05) for nutritive value variables since it decreased as forages became mature. The ADG observed (0.44 kg) for all systems (P=0.78) during summer was lower than expected and might have been limited by the observed temperature as well as forage nutritive value. Systems 1 and 2 had more grazing days (P=0.03) during summer (155 and 146 d, respectively) compared to System 3 (132 d) due to the greater pasture area of bermudagrass in those systems. Steers in System 3 were fed more hay for a longer period of time (P<0.05) than on the other 2 systems. System 1 and 2 produced more hay per hectare than System 3 (P<0.05). No differences (P>0.05) were detected between systems in ADG year round, during the winter season, or carcass characteristics. Return over total direct costs and total specified expenses were greater for Systems 1 and 2, while System 3 was the lowest. Hay making and bale sales played a major role in explaining the economic results of this study. Where possible, year-round forage systems are a viable alternative for forage-fed beef production; however, the low gains during summer and forage availability during the transition period when hay is necessary deserve further research to find alternatives to improve productivity during those times of the year.

Global burden of severe periodontitis in 1990-2010: a systematic review and meta-regression

We aimed to consolidate all epidemiologic data about severe periodontitis (SP) and, subsequently, to generate internally consistent prevalence and incidence estimates for all countries, 20 age groups, and both sexes for 1990 and 2010. The systematic search of the literature yielded 6,394 unique citations. After screening titles and abstracts, we excluded 5,881 citations as clearly not relevant to this systematic review, leaving 513 for full-text review. A further 441 publications were excluded following the validity assessment. A total of 72 studies, including 291,170 individuals aged 15 yr or older in 37 countries, were included in the metaregression based on modeling resources of the Global Burden of Disease 2010 Study. SP was the sixth-most prevalent condition in the world. Between 1990 and 2010, the global age-standardized prevalence of SP was static at 11.2% (95% uncertainty interval: 10.4%-11.9% in 1990 and 10.5%-12.0% in 2010). The age-standardized incidence of SP in 2010 was 701 cases per 100,000 person-years (95% uncertainty interval: 599-823), a nonsignificant increase from the 1990 incidence of SP. Prevalence increased gradually with age, showing a steep increase between the third and fourth decades of life that was driven by a peak in incidence at around 38 yr of age. There were considerable variations in prevalence and incidence between regions and countries. Policy makers need to be aware of a predictable increasing burden of SP due to the growing world population associated with an increasing life expectancy and a significant decrease in the prevalence of total tooth loss throughout the world from 1990 to 2010.

Global Burden of Severe Tooth Loss: A Systematic Review and Meta-analysis

The goal of the Global Burden of Disease 2010 Study has been to systematically produce comparable estimates of the burden of 291 diseases and injuries and their associated 1,160 sequelae from 1990 to 2010. We aimed to report here internally consistent prevalence and incidence estimates of severe tooth loss for all countries, 20 age groups, and both sexes for 1990 and 2010. The systematic search of the literature yielded 5,618 unique citations. After titles and abstracts were screened, 5,285 citations were excluded as clearly not relevant to this systematic review, leaving 333 for full-text review; 265 publications were further excluded following the validity assessment. A total of 68 studies-including 285,746 individuals aged 12 yr or older in 26 countries-were included in the meta-analysis using modeling resources of the Global Burden of Disease 2010 Study. Between 1990 and 2010, the global age-standardized prevalence of edentate people decreased from 4.4% (95% uncertainty interval: 4.1%, 4.8%) to 2.4% (95% UI: 2.2%, 2.7%), and incidence rate decreased from 374 cases per 100,000 person-years (95% UI: 347, 406) to 205 cases (95% UI: 187, 226). No differences were found by sex in 2010. Prevalence increased gradually with age, showing a steep increase around the seventh decade of life that was associated with a peak in incidence at 65 years. Geographic differences in prevalence, incidence, and rate of improvement from 1990 to 2010 were stark. Our review of available quality literature on the epidemiology of tooth loss shows a significant decline in the prevalence and incidence of severe tooth loss between 1990 and 2010 at the global, regional, and country levels.

The Gly(972)Arg variant of human IRS1 gene is associated with variation in glomerular filtration rate likely through impaired insulin receptor signaling

The objective of this study is to identify and characterize the genetic variants related to the glomerular filtration rate (GFR) linkage on 2q37. Of the positional candidate genes, we selected IRS1 and resequenced its 2-kb promoter region and exons for sequence variants in 32 subjects. A total of 11 single nucleotide polymorphisms (SNPs) were identified. To comprehensively cover the 59-kb-long intron-1, eight additional tagging SNPs were selected from the HapMap. All the 19 SNPs were genotyped by TaqMan Assay in the entire data set (N = 670; 39 families). Association analyses between the SNPs and GFR and type 2 diabetes-related traits were performed using the measured genotype approach. Of the SNPs examined for association, only the Gly(972)Arg variant of IRS1 exhibited a significant association with GFR (P = 0.0006) and serum triglycerides levels (P = 0.003), after accounting for trait-specific covariate effects. Carriers of Arg972 had significantly decreased GFR values. Gly(972)Arg contributed to 26% of the linkage signal on 2q. Expression of IRS1 mutant Arg972 in human mesangial cells significantly reduced the insulin-stimulated phosphorylation of IRS1 and Akt kinase. Taken together, the data provide the first evidence that genetic variation in IRS1 may influence variation in GFR probably through impaired insulin receptor signaling.

Tuberin inhibits production of the matrix protein fibronectin in diabetes

Exposure of proximal tubular epithelial cells to high glucose contributes to the accumulation of tubulointerstitial and matrix proteins in diabetic nephropathy, but how this occurs is not well understood. We investigated the effect of the signaling molecule tuberin, which modulates the mammalian target of rapamycin pathway, on renal hypertrophy and fibronectin expression. We found that the kidney mass was significantly greater in partially tuberin-deficient (TSC2(+/-) ) diabetic rats than wild-type diabetic rats. Furthermore, TSC2(+/-) rats exhibited significant increases in the basal levels of phospho-tuberin and fibronectin expression in the kidney cortex. Increased levels of phosphorylated tuberin associated with an increase in fibronectin expression in both wild-type and TSC2(+/-) diabetic rats. Treatment with insulin abrogated the diabetes-induced increase in fibronectin expression. In vitro, high glucose enhanced fibronectin expression in TSC2(+/-) primary proximal tubular epithelial cells; both inhibition of Akt and inhibition of the mammalian target of rapamycin could prevent this effect of glucose. In addition, forced expression of tuberin in tuberin-null cells abolished the expression of fibronectin protein. Taken together, these data suggest that tuberin plays a central role in the development of renal hypertrophy and in modulating the production of the matrix protein fibronectin in diabetes.

Differential concentration and time dependent effects of progesterone on kinase activity, hyperactivation and acrosome reaction in human spermatozoa

Progesterone has been identified to be one of the physiological regulators of sperm hyperactivation and acrosome reaction. However, the high sensitivity of human spermatozoa to progesterone implies that many may undergo premature hyperactivation and acrosome reaction thereby compromising their ability to fertilize. We hypothesized that if a spermatozoon has to preclude the occurrence of these events prematurely, there should be differential dose- and time-dependent effects on motility and acrosome reaction. We observed that low concentrations of progesterone (10 and 100 nm) induce sperm motility and activate tyrosine kinase; higher concentrations (1-10 μm) are required to induce extracellular signal regulated kinases 1/2 (Erk1/2), p90 ribosomal S6 kinase (p90RSK), p38 mitogen-activated protein kinase (p38MAPK), c-Jun N-terminal kinase (JNK1) and AKT phosphorylation, hyperactivation and acrosome reaction. The induction of acrosome reaction and tyrosine phosphorylation in response to higher concentration of progesterone is not absolutely dependent on activation of T-type voltage-gated Ca(2+) channel or CatSper as Mibefradil did not completely abrogate progesterone-mediated effects. These results imply that although the spermatozoa are sensitive to low concentrations of progesterone, they only activate motility and tyrosine kinase activation; higher concentrations are required to induce hyperactivation and acrosome reaction probably by activating multiple kinase pathways including the MAPK and AKT.

Health seeking behavior during pregnancy and child birth among Muslim women of Biratnagar, Nepal

Maternal mortality remains one of the biggest public health challenges in Nepal. This paper explores the health seeking behavior, during pregnancy and child birth in certain ethnic group. The poverty, illiteracy, women's low status in the society, lack of access and difficult geographical terrain are major reasons for poor maternal health status in Nepal. Cross-sectional study was conducted among 200 Muslim women of ward # 7 of Biratnagar municipality. They were interviewed to understand their health seeking behavior during pregnancy and childbirth, factors associated with use of health services and their role in the family. Information's on usages of health services, education level, family stricture, and occupational status, information were collected using a pretested and structured questionnaire. The overall institutional delivery in study population was found 24.5%. Low socio-economic status, Illiteracy and poverty in women are the major challenging features of pregnancy and child birth.

Tuberin regulates the DNA repair enzyme OGG1

The tuberous sclerosis complex (TSC) is caused by defects in one of two tumor suppressor genes, TSC-1 or TSC-2. The TSC-2 gene encodes tuberin, a protein involved in the pathogenesis of kidney tumors, both angiomyolipomas and renal cell carcinomas. We investigated a potential role for tuberin in regulating a key DNA repair pathway. Downregulation of tuberin in human renal epithelial cells using siRNA resulted in a marked decrease in the abundance of the 8-oxoG-DNA glycosylase (OGG1). Mouse embryonic fibroblasts deficient in tuberin (TSC2(-/-) and TSC2(+/-)) also had markedly decreased OGG1 mRNA and protein expression, as well as undetectable OGG1 activity accompanied by accumulation of 8-oxodG. Gel shift analyses and chromatin immunoprecipatation identified the transcription factor NF-YA as a regulator of OGG1 activity. The binding of NF-YA to the OGG1 promoter was significantly reduced in TSC2(-/-) compared with TSC2(+/+) cells. Introduction of TSC2 cDNA into the tuberin-deficient cells restored NF-YA and OGG1 expression. Transcriptional activity of the OGG1 promoter was also decreased in tuberin-null cells. In addition, mutation of both CAAT boxes, the sites to which NF-YA binds, completely inhibits OGG1 promoter activity. These data provide the first evidence that tuberin regulates a specific DNA repair enzyme, OGG1. This regulation may be important in the pathogenesis of kidney tumors in patients with TSC.

Arachidonic acid-dependent activation of a p22(phox)-based NAD(P)H oxidase mediates angiotensin II-induced mesangial cell protein synthesis and fibronectin expression via Akt/PKB

Angiotensin II (Ang II) induces protein synthesis and hypertrophy through arachidonic acid (AA)- and redoxdependent activation of the serine-threonine kinase Akt/PKB in mesangial cells (MCs). The role of NAD(P)H oxidase component p22( phox ) was explored in this signaling pathway and in Ang II-induced expression of the extracellular matrix protein fibronectin. Ang II causes activation of Akt/PKB and induces fibronectin protein expression, effects abrogated by phospholipase A(2) inhibition and mimicked by AA. Ang II and AAalso elicited an increase in fibronectin expression that was reduced with a dominant negative mutant of Akt/PKB. Exposure of the cells to hydrogen peroxide stimulates Akt/PKB activity and fibronectin synthesis. The antioxidant N-acetylcysteine abolished Ang II- and AA-induced Akt/PKB activation and fibronectin expression. Western blot analysis revealed high levels of p22( phox ) in MCs. Antisense (AS) but not sense oligonucleotides for p22( phox ) prevented ROS generation in response to Ang II and AA. AS p22( phox ) inhibited Ang II- or AA-induced Akt/PKB as well as protein synthesis and fibronectin expression. These data provide the first evidence, in MCs, of activation by AAof a p22( phox )-based NAD(P)H oxidase and subsequent generation of ROS. Moreover, this pathway mediates the effect of Ang II on Akt/PKB-induced protein synthesis and fibronectin expression.

ZO-1 expression and phosphorylation in diabetic nephropathy

Cellular mechanisms responsible for the loss of capillary wall permselectivity in diabetic nephropathy are not well characterized. ZO-1 is a junctional protein involved in the assembly and proper function of a number of tight junctions and is also expressed at the junction of podocytes with the slit diaphragm. We investigated the effect of diabetes and high glucose concentration on the expression of ZO-1 in animal models of both type 1 and 2 diabetes and in rat glomerular epithelial cells. In diabetic animals, immunohistochemistry and Western blotting showed decreased expression of ZO-1 in glomeruli. Immunogold electron microscopy revealed redistribution of ZO-1 from the podocyte membrane to the cytoplasm in the diabetic animals. Exposure of rat glomerular epithelial cells to high glucose resulted in a decrease in the intensity of ZO-1 staining and redistribution of ZO-1 from the membrane to the cytoplasm, changes that are attenuated by blockade of the angiotensin II type 1 receptor. ZO-1 protein expression and serine and tyrosine phosphorylation of ZO-1 were also decreased in cells exposed to high glucose. These findings suggest that alterations in the content and localization of ZO-1 may be relevant to the pathogenesis of proteinuria in diabetes.

PI 3 kinase-dependent Akt kinase and PKCε independently regulate interferon-γ-induced STAT1α serine phosphorylation to induce monocyte chemotactic protein-1 expression

Monocyte chemotactic protein-1 (MCP-1) recruits activated phagocytes to the site of tissue injury. Interferon-gamma (IFN-gamma) present in the microenvironment of glomerulus acts on mesangial cells to induce local production of MCP-1. The mechanism by which IFN-gamma stimulates expression of MCP-1 is not clear. We therefore examined the role of PI 3 kinase signaling in regulating the IFN-gamma-induced MCP-1 expression in mesangial cells. Blocking PI 3 kinase activity with Ly294002 attenuated IFN-gamma-induced MCP-1 protein and mRNA expression. IFN-gamma increased Akt kinase activity in a PI 3 kinase-dependent manner. Expression of dominant negative Akt kinase inhibited serine phosphorylation of STAT1alpha, without any effect on its tyrosine phosphorylation, and decreased IFN-gamma-induced expression of MCP-1. These data for the first time indicate a role for PI 3 kinase-dependent Akt kinase in MCP-1 expression. We have recently shown that along with Akt, PKCepsilon is a downstream target of PI 3 kinase in IFN-gamma signaling. Similar to dominant negative Akt kinase, dominant negative PKCepsilon also inhibited serine phosphorylation of STAT1alpha without any effect on tyrosine phosphorylation. Dominant negative PKCepsilon also abrogated MAPK activity, resulting in decrease in IFN-gamma-induced MCP-1 expression. Furthermore, Akt and PKCepsilon are present together in a signaling complex. IFN-gamma had no effect on this complex formation, but did increase PKCepsilon-associated Akt kinase activity. PKCepsilon did not regulate IFN-gamma-induced Akt kinase. Finally, expression of dominant negative Akt kinase blocked IFN-gamma-stimulated MAPK activation. These data provide the first evidence that PI 3 kinase-dependent Akt and PKCepsilon activation independently regulate MAPK activity and serine phosphorylation of STAT1alpha to increase expression of MCP-1.

Redox dependence of glomerular epithelial cell hypertrophy in response to glucose

Podocytes or glomerular epithelial cells (GECs) are important targets of the diabetic microenvironment. Podocyte foot process effacement and widening, loss of GECs and hypertrophy are pathological features of this disease. ANG II and oxidative stress are key mediators of renal hypertrophy in diabetes. The cellular mechanisms responsible for GEC hypertrophy in diabetes are incompletely characterized. We investigated the effect of high glucose on protein synthesis and GEC hypertrophy. Exposure of GECs to high glucose dose dependently stimulated [(3)H]leucine incorporation, but not [(3)H]thymidine incorporation. High glucose resulted in the activation of ERK1/2 and Akt/PKB. ERK1/2 pathway inhibitor or the dominant negative mutant of Akt/PKB inhibited high glucose-induced protein synthesis. High glucose elicited a rapid generation of reactive oxygen species (ROS). The stimulatory effect of high glucose on ROS production, ERK1/2, and Akt/PKB activation was prevented by the antioxidants catalase, diphenylene iodonium, and N-acetylcysteine. Exposure of the cells to hydrogen peroxide mimicked the effects of high glucose. In addition, ANG II resulted in the activation of ERK1/2 and Akt/PKB and GEC hypertrophy. Moreover, high glucose and ANG II exhibited additive effects on ERK1/2 and Akt/PKB activation as well as protein synthesis. These additive responses were abolished by treatment of the cells with the antioxidants. These data demonstrate that high glucose stimulates GEC hypertrophy through a ROS-dependent activation of ERK1/2 and Akt/PKB. Enhanced ROS generation accounts for the additive effects of high glucose and ANG II, suggesting that this signaling cascade contributes to GEC injury in diabetes.

Nox4 NAD(P)H oxidase mediates hypertrophy and fibronectin expression in the diabetic kidney

Renal hypertrophy and extracellular matrix accumulation are early features of diabetic nephropathy. We investigated the role of the NAD(P)H oxidase Nox4 in generation of reactive oxygen species (ROS), hypertrophy, and fibronectin expression in a rat model of type 1 diabetes induced by streptozotocin. Phosphorothioated antisense (AS) or sense oligonucleotides for Nox4 were administered for 2 weeks with an osmotic minipump 72 h after streptozotocin treatment. Nox4 protein expression was increased in diabetic kidney cortex compared with non-diabetic controls and was down-regulated in AS-treated animals. AS oligonucleotides inhibited NADPH-dependent ROS generation in renal cortical and glomerular homogenates. ROS generation by intact isolated glomeruli from diabetic animals was increased compared with glomeruli isolated from AS-treated animals. AS treatment reduced whole kidney and glomerular hypertrophy. Moreover, the increased expression of fibronectin protein was markedly reduced in renal cortex including glomeruli of AS-treated diabetic rats. Akt/protein kinase B and ERK1/2, two protein kinases critical for cell growth and hypertrophy, were activated in diabetes, and AS treatment almost abolished their activation. In cultured mesangial cells, high glucose increased NADPH oxidase activity and fibronectin expression, effects that were prevented in cells transfected with AS oligonucleotides. These data establish a role for Nox4 as the major source of ROS in the kidneys during early stages of diabetes and establish that Nox4-derived ROS mediate renal hypertrophy and increased fibronectin expression.

Angiotensin II-induced ERK1/ERK2 activation and protein synthesis are redox-dependent in glomerular mesangial cells

Angiotensin II (Ang II) stimulates hypertrophy of glomerular mesangial cells. The signalling mechanism by which Ang II exerts this effect is not precisely known. Downstream potential targets of Ang II are the extracellular-signal-regulated kinases 1 and 2 (ERK1/ERK2). We demonstrate that Ang II activates ERK1/ERK2 via the AT1 receptor. Arachidonic acid (AA) mimics the action of Ang II on ERK1/ERK2 and phospholipase A2 inhibitors blocked Ang II-induced ERK1/ERK2 activation. The antioxidant N-acetylcysteine as well as the NAD(P)H oxidase inhibitors diphenylene iodonium and phenylarsine oxide abolished both Ang II- and AA-induced ERK1/ERK2 activation. Moreover, dominant-negative Rac1 (N17Rac1) blocks activation of ERK1/ERK2 in response to Ang II and AA, whereas constitutively active Rac1 resulted in an increase in ERK1/ERK2 activity. Antisense oligonucleotides for Nox4 NAD(P)H oxidase significantly reduce activation of ERK1/ERK2 by Ang II and AA. We also show that protein synthesis in response to Ang II and AA is inhibited by N17Rac1 or MEK (mitogen-activated protein kinase/ERK kinase) inhibitor. These results demonstrate that Ang II stimulates ERK1/ERK2 by AA and Nox4-derived reactive oxygen species, suggesting that these molecules act as downstream signal transducers of Ang II in the signalling pathway linking the Ang II receptor AT1 to ERK1/ERK2 activation. This pathway involving AA, Rac1, Nox4, reactive oxygen species and ERK1/ERK2 may play an important role in Ang II-induced mesangial cell hypertrophy.

Leptospirosis and Weil's disease in eastern India

Leptospirosis is characterised by a broad spectrum of clinical manifestations varying from inapparent infection to fulminant fatal disease. Severe leptospirosis characterised by profound jaundice is referred to as Weil's disease. In the present study 20 patients of leptospirosis, of which 7 belonged to Weil's disease, were diagnosed based on the demonstration of IgM antileptospira antibody and supported by clinical correlation and appropriate biochemical markers. Overall, the male and female ratio was 17:3 and the same ratio for the Weil's disease was 6:1. The most common presentation involved fever, malaise and myalgia. Conjunctival congestion was found in 75% of the cases and jaundice was encountered in 90% of the cases. The prognosis of all these patients, including that of Weil's disease was excellent. Early recognition and initiation of antibiotic therapy were found to be important.

Nox4 mediates angiotensin II-induced activation of Akt/protein kinase B in mesangial cells

ANG II induces protein synthesis through the serine-threonine kinase Akt/protein kinase B (PKB) in mesangial cells (MCs). The mechanism(s) of activation of Akt/PKB particularly by G protein-coupled receptors, however, is not well characterized. We explored the role of the small GTPase Rac1, a component of the phagocyte NADPH oxidase, and the gp91phox homologue Nox4/Renox in this signaling pathway. ANG II causes rapid activation of Rac1, an effect abrogated by phospholipase A2 inhibition and mimicked by arachidonic acid (AA). Northern blot analysis revealed high levels of Nox4 transcript in MCs and transfection with antisense (AS) oligonucleotides for Nox4 markedly decreased NADPH-dependent reactive oxygen species (ROS)-producing activity. Dominant negative Rac1 (N17Rac1) as well as AS Nox4 inhibited ROS generation in response to ANG II and AA, whereas constitutively active Rac1 stimulated ROS formation. Moreover, N17Rac1 blocked stimulation of NADPH oxidase activity by AA. N17Rac1 or AS Nox4 abolished ANG II- or AA-induced activation of the hypertrophic kinase Akt/PKB. In addition, AS Nox4 inhibited ANG II-induced protein synthesis. These data provide the first evidence that activation by AA of a Rac1-regulated, Nox4-based NAD(P)H oxidase and subsequent generation of ROS mediate the effect of ANG II on Akt/PKB activation and protein synthesis in MCs.

Cloning of the 5'-flanking region of the murine bone morphogenetic protein-7 gene

BMP-7, a member of the bone morphogenetic protein subfamily of the TGFbeta-superfamily is highly expressed in the murine kidney. BMP-7 is involved in fetal nephron development and mesenchymal to epithelial cell differentiation. Constitutive BMP-7 expression is found in tubular and glomerular epithelial cells of the adult kidney. BMP-7 may play a role in physiology and pathophysiology of the adult kidney since BMP-7 gene expression in acute renal ischemia is diminished and injection of recombinant BMP-7 into rats with ischemic acute renal failure preserves renal function. In order to investigate the transcriptional regulation of BMP-7, this study was undertaken to clone and characterize the promoter of the murine BMP-7 gene. A 1394 bp sequence of the 5'-flanking region of the BMP-7 gene was isolated and subcloned. No TATA and CAAT box consensus motifs could be identified as shown for promoters of other BMPs. Using in vitro transfection assays, the 5'-flanking region revealed moderate to strong basal promoter activity. PMA increased basal BMP-7 promoter activity. Thus BMP-7 gene transcription might involve at least in part a PKC-dependent pathway. The cloning of a 5'-flanking region of the BMP-7 gene should provide a useful tool for future studies on the transcriptional regulation of BMP-7 gene expression.

Angiotensin II activates Akt/protein kinase B by an arachidonic acid/redox-dependent pathway and independent of phosphoinositide 3-kinase

Angiotensin II (Ang II) exerts contractile and trophic effects in glomerular mesangial cells (MCs). One potential downstream target of Ang II is the protein kinase Akt/protein kinase B (PKB). We investigated the effect of Ang II on Akt/PKB activity in MCs. Ang II causes rapid activation of Akt/PKB (5-10 min) but delayed activation of phosphoinositide 3-kinase (PI3-K) (30 min). Activation of Akt/PKB by Ang II was not abrogated by the PI3-K inhibitors or by the introduction of a dominant negative PI3-K, indicating that in MCs, PI3-K is not an upstream mediator of Akt/PKB activation by Ang II. Incubation of MCs with phospholipase A2 inhibitors also blocked Akt/PKB activation by Ang II. AA mimicked the effect of Ang II. Inhibitors of cyclooxygenase-, lipoxyogenase-, and cytochrome P450-dependent metabolism did not influence AA-induced Akt/PKB activation. However, the antioxidants N-acetylcysteine and diphenylene iodonium inhibited both AA- and Ang II-induced Akt/PKB activation. Dominant negative mutant of Akt/PKB or antioxidants, but not the dominant negative form of PI3-K, inhibited Ang II-induced protein synthesis and cell hypertrophy. These data provide the first evidence that Ang II induces protein synthesis and hypertrophy in MCs through AA/redox-dependent pathway and Akt/PKB activation independent of PI3-K.

Kawasaki disease--Indian perspective

Kawasaki disease is a syndrome of unknown etiology affecting children below 5 years of age and is a leading cause of acquired heart disease in many developed countries. Incidence of this disease in India is extremely low as evidenced by the meagre case reports. Complications due to this disease in Indian patients are still rarer. Here we report two cases of Kawasaki disease both of whom had a benign course. A comparison of this disease in Indian and Western literature shows that the incidence of cardiac complications in the Indian patients is about 10% while in the west it is reported at around 30%. This paucity of complications in the Indian patients may be the reason of poor reporting of this disease in our country.

Identification of promoter activity and differential expression of transcripts encoding the murine stromelysin-1 gene in renal cells

Stromelysin-1, matrix metalloproteinase-3 (MMP-3), is an important endopeptidase selectively expressed by somatic cells in organ tissues. The renal tubulointerstitium, for example, comprises tubular epithelium and interstitial fibroblasts forming the principal mass of the kidney. We observed that mRNA encoding stromelysin-1 is detectable in murine renal fibroblasts, but not in proximal tubular epithelium. Transcripts measured by RNase protection assay in renal fibroblasts increase following exposure to phorbol ester, and thereafter, activated stromelysin-1 protein can be detected in culture media by Western blotting. A 6.4 Kb genomic clone containing the putative stromelysin-1 promoter was isolated and a relevant 2.1 Kb PstI restriction fragment including 2.1 Kb of the immediate 5'-flanking region was sequenced on both strands. Two transcriptional start sites were identified by primer extension; the major start site corresponded to a previously established position in the rat promoter, and a second undescribed minor transcriptional start site was located 16 bp upstream of the primary site. A HiNF-A chromatin-activating element at -106 bp was found in the early promoter region of pR336 and an active AP-1 site at -72 bp with an Ets/PEA-3 motif at -203 bp was suggested by transient transfection of luciferase minigenes into renal fibroblasts responsive to phorbol ester. This Ets element was identical to a site in the early promoter of the fibroblast-specific gene FSP1. A baseline enhancement in activity of pR336 in fibroblasts was further observed with the addition of 5' flanking sequence out to -1980 bp. This additional region of flanking sequence contains two modular regions: one of multiple PEA-3 elements between -684 bp and -1955 bp and a second region between -1929 bp and -1980 bps containing a second AP-1 site at -1929 bp, a MBF-1/ MEP-1 metal binding site, and a PPAR peroxisome proliferator element at -1950 bp. Our findings implicate a gene structure with expected activity in a mesenchymal phenotype. The PKC-dependent regulation of the stromelysin-1 gene supports the notion that it may be modulated during inflammation or tissue remodeling.

Cyclic AMP regulates basement membrane heparan sulfate proteoglycan, perlecan, metabolism in rat glomerular epithelial cells

Perlecan, the basement membrane heparan sulfate proteoglycan (HSPG), has been fully cloned from mouse and human tissues. When a cRNA probe of murine perlecan cDNA was employed in RNase protection assay to test whether rat glomerular epithelial cells (GEC) constitutively express perlecan, several bands of hybridization were seen, suggesting that sequences between rat and murine perlecan may not be identical. Using primers based on published cDNA sequences of murine and human perlecan and poly A+ RNA of rat GEC, we synthesized a 497 bp product (RPD-I) by RT-PCR. The deduced aminoacid sequence showed an 85% and 88% homology with domain I of murine and human perlecan, respectively. The three putative sites containing the consensus sequence SGD for attachment of heparan sulfate chains were fully conserved in the rat perlecan as was a site (NFT) for attachment of N-linked oligosaccharide. RPD-I detected a > 9.5 kb transcript of perlecan in RNA of GEC, similar in size to that present in rat glomeruli. Employing a riboprobe synthesized from RPD-I in RNase protection assay we examined whether dbcAMP regulated perlecan expression in the GEC. At 1, 6, 24 and 48 h of incubation, 1 mM dbcAMP caused 43%, 32%, 47% and 40% reduction in mRNA abundance of perlecan, respectively. Immunoprecipitation showed a corresponding reduction of 61%, 70% and 65% in the synthesis of 35SO4 labeled basement membrane HSPG by the GEC following 12, 24 and 48 h of incubation with dbcAMP. Following incubation for 1 and 24 h prostaglandins, PGE1 and PGE2 (1 uM), known activators of glomerular adenylate cyclase, reduced perlecan mRNA abundance to a similar extent as dbcAMP on northern analysis. Our results show that glomerular basement membrane HSPG synthesized by the GEC belongs to the perlecan family. Decrease of GEC perlecan gene expression and synthesis by cAMP and prostaglandins may be of relevance to proteinuric states characterized by activation of these mediators.

A nuclear protein in mesangial cells that binds to the promoter region of the platelet-derived growth factor-A chain gene. Induction by phorbol ester

Mesangial cells predominantly express platelet-derived growth factor (PDGF)-A chain mRNA and release PDGF. Mesangial cell PDGF-A chain mRNA abundance is regulated by several agents including phorbol esters. We have recently demonstrated that induction of PDGF-A chain mRNA abundance in response to phorbol 12-myristate 13-acetate is primarily due to gene transcription. We have now analyzed the 5'-flanking region of the PDGF-A chain promoter to identify DNA binding protein(s) which have the potential to regulate PDGF-A chain gene transcription in human mesangial cells. DNase I footprint analysis of the 5'-flanking region of the PDGF-A chain promoter identifies a DNase I protected region at the location -82 to -102 corresponding to the sequence 5'-GGCCCGGAATCCGGGGGAGGC-3'. Therefore, nuclear extracts from human mesangial cells contain a protein, PDGF-A-BP-1, that binds to a DNA sequence (-82 to -102) in the promoter region of the PDGF-A chain gene. Gel mobility shift analysis using labeled oligomer corresponding to the binding site for PDGF-A-BP-1 indicates that PDGF-A-BP-1 is induced by phorbol ester in mesangial cells as well as fat-storing cells (> 20 fold). Egr-1 protein does not bind to labeled PDGF-A-BP-1 oligomer and does not compete with the binding of PDGF-A-BP-1. In addition, SP-1 binding sequence does not compete with the binding sequence of the mesangial cell protein. PDGF-A-BP-1 appears to represent a novel protein which is induced by phorbol ester and thus has the potential for an important role in the transcriptional regulation of the PDGF-A chain gene in mesangial cells and other vascular pericytes.

Platelet-derived growth factor B-chain gene expression in mesangial cells: effect of phorbol ester on gene transcription and mRNA stability

We have investigated the effect of phorbol 12-myristate 13-acetate (PMA) on platelet-derived growth factor (PDGF) B-chain gene transcription as well as on mRNA stability in cultured human mesangial cells. Addition of actinomycin to cells stimulated with PMA decreases steady state levels of PDGF-B chain mRNA analysed by solution hybridization assay. PDGF-B chain gene transcription was also assayed directly by measuring elongation of transcripts in isolated nuclei followed by hybridization of labeled RNA transcripts to a cDNA encoding for PDGF-B chain. Our data show that PMA induces PDGF-B chain gene transcription by approximately 2-fold. alpha-Amanitin, an RNA polymerase II inhibitor, blocked transcription by more than 70%. In addition, we determined the effect of PMA on the halflife of PDGF-B chain mRNA directly by pulse chase method. In human mesangial cells, the PDGF-B chain mRNA exhibited halflife of approximately 105 min. In the presence of PMA, the halflife of PDGF-B chain mRNA was reduced to approximately 72 min. These studies indicate that regulation of PDGF-B chain gene by PMA in human mesangial cells involves a coordinate effort at the level of transcription and mRNA stability.

Platelet-derived growth factor (PDGF) BB homodimer regulates PDGF A- and PDGF B-chain gene transcription in human mesangial cells

Mesangial cells express platelet-derived growth factor (PDGF) A- and B-chain mRNA and release PDGF. Several polypeptide growth factors, including PDGF itself, induce PDGF A- and B- chain mRNA abundance. To understand the molecular mechanisms associated with the changes in mRNA abundance, we measured the effects of PDGF BB homodimer on PDGF A- and B-chain gene transcription in cultured mesangial cells. The data demonstrate 2- and 4-fold increases in PDGF A-chain gene transcription in response to PDGF BB homodimer at 5 and 24 h time points respectively. PDGF B-chain gene transcription was also induced approximately 3-fold at 2, 5 and 24 h time points in response to treatment with PDGF BB homodimer. The effect of PDGF BB on the half-life of PDGF A- as well as PDGF B-chain mRNA was measured directly by the pulse-chase method. There was no effect on PDGF A-chain mRNA half-life whereas PDGF B-chain mRNA half-life was increased 1.5-fold. These studies indicate that, in human mesangial cells, the increase in the levels of PDGF A- and B-chain mRNA in response to PDGF- receptor(s) activation is mediated at the level of gene transcription. In addition, the regulation of PDGF B- but not PDGF A-chain gene involves increased mRNA stability. Mesangial cells are a useful model for studying molecular mechanisms of PDGF- gene regulation in non-transformed human cells.

Effect of vasodilator therapy on mortality in chronic congestive heart failure

We compared the effects of Hydralazine and Isosorbide dinitrate (ISDN) with those of an angiotensin-converting-enzyme inhibitor, captopril on mortality in patients with chronic congestive heart failure (NYHA class III and IV). Patients receiving conventional treatment with digoxin and diuretics were randomly assigned to receive either placebo (n = 51), hydralazine-ISDN. (n = 50) or captopril (n = 52) in a double blind trial. At the end of 6 months there were 14 deaths in the placebo group (27.4%) as compared with 11 deaths in the hydralazine-ISDN group (22%)--a mortality reduction of 20% (P > 0.05) and 10 deaths in the captopril group (19.2%)--a mortality reduction of 30% (p > 0.05). At the end of one year, mortality was 50%, 42% and 30% in the placebo, hydralazine-ISDN and captopril groups respectively with a mortality reduction of 16% in the hydralazine-ISDN group (p > 0.05) and 40% in the captopril group (p < 0.05) compared to the placebo group. The mortality reduction was mainly due to reduction in deaths attributed to progressive heart failure. The data suggests that the addition of captopril to conventional treatment significantly reduces mortality in patients with severe congestive heart failure. Hydralazine-isorobide dinitrate also reduced mortality but statistically this was not significant.