Tobacco use, secondhand exposure and knowledge of secondhand and third-hand smoke among medical college students in Western Nepal: a cross-sectional study.

OBJECTIVES: This study was conducted to assess the prevalence of tobacco use, secondhand smoke (SHS) exposure and knowledge about SHS and third-hand smoke (THS) exposure among students in a medical college in Western Nepal. DESIGN: This is a cross-sectional study. SETTING: Data collection was done from 8 July 2023 to 8 August 2023 in a medical college in Nepal. PARTICIPANTS: This study was conducted on undergraduate students studying in a medical college in Western Nepal using a census (whole population) sampling technique. MAIN OUTCOME MEASURES: Prevalence of tobacco use was assessed by asking a question, 'Did you use tobacco products within the last 30 days?'. Secondhand smoke exposure and knowledge about SHS and THS exposure were assessed by using structured questionnaires. The χ2 test was used to compare the group exposed and non-exposed to tobacco, SHS and THS by sociodemographic variables (sex, residence, year of study and academic stream). RESULTS: The response rate was 96.43% (n=595/617). The overall prevalence of tobacco use was found to be 16.30%. A total of 88.83% of students from clinical years knew about SHS which was more than preclinical students (p <0.001). The Bachelor of Medicine and Bachelor of Surgery students have higher knowledge of SHS as compared with others (p =0.003). More than 95% of students favoured banning smoking in public places. Nearly half of the participants (45.45%) experienced SHS exposure in the last 7 days. More than half proportion of the clinical students knew about THS, which was higher than preclinical students and interns (p <0.001). CONCLUSIONS: Tobacco use prevalence among the participants was found to be lower in comparison to other studies including medical students in several Asian countries. Despite more than three-fourths of students knowing the harmful effects of SHS exposure, almost one-half of them were exposed to SHS. The proportion of students who knew about THS exposure was comparably lower.

Dental caries, tobacco usage and associated risk factor of dental caries in patients visiting a government hospital in Western, Nepal.

BACKGROUND: This study was conducted to assess the prevalence of dental caries, tobacco usage, and associated risk factors for dental caries in patients who visited a government hospital in Western, Nepal. METHODS: This analytical cross-sectional study was conducted from January to April 2022. Patients above 18 years visiting the dental OPD of a government hospital, and who had provided informed consent were enrolled in the study using a convenience sampling technique. As the study also involved an illiterate population, in that case, informed consent was obtained from their respective legal guardian as well. A pretested standardized, close-ended questionnaire was administered by researchers to gather information regarding the associated risk factors and oral hygiene practices. Clinical examination was done for dental caries according to the criteria by the World Health Organization (WHO) using the "DMFT" index (WHO modification 1987). Bivariate and multivariable logistic regression was done and the odds ratio and p-value was calculated. For all tests, statistical significance was set at p < 0.05. RESULTS: A total of 219 participants completed the study with a mean age of 31.73 ± 12.46. The prevalence of dental caries and tobacco was found to be 80.36% and 5.02% respectively. Participants without health insurance had 2.35 times higher odds of dental caries (95% CI: 1.03-5.36). Not rinsing the mouth after eating sweets was associated with 3.07 times higher odds of dental caries (95% CI: 1.31-7.18). Those who hadn't visited a dentist in the past 12 months had lower odds (0.42; 95% CI: 0.18-0.94). Eating fresh fruit daily showed statistically higher odds (2.70; 95% CI: 1.04-6.99) of dental caries. Non-tobacco users had higher odds (14.19; 2.55-78.99) of dental caries. CONCLUSION: Dental caries is highly prevalent, while tobacco usage is relatively low. Factors associated with dental caries included lack of health insurance coverage, consumption of fruits once daily, recent dental visits within the past year, not rinsing the mouth with water after consuming sweets, and non-tobacco users.

Jejunojejunal intussusception in an adult due to adenoma: a case report.

Intussusception is a rare condition in adults and presents a diagnostic challenge. Clinical presentation tends to be chronic and non-specific. Unlike the pediatric population, most adult intussusceptions have structural lesions as lead points. Here, we present a case of jejunojejunal intussusception in a 27-year female due to adenoma of small bowel.

Assessment of nicotine dependence among tobacco users visiting outreach programs in Dharan, Nepal: a cross-sectional study.

BACKGROUND: Nicotine is a highly addictive substance present in tobacco. This study was conducted to assess the level of nicotine dependence among smokers and smokeless tobacco users visiting dental outreach programs of B.P. Koirala Institute of Health Sciences -Dharan, Nepal. METHODS: A cross sectional study was conducted from June 2018 to April 2019. A total of 726 people were selected from participants of dental outreach programs of 6 districts using convenience sampling technique. The data collection was done using semi-structured questionnaire through face-to-face interview by a single researcher. History of tobacco use and level of nicotine dependency was measured using Nepali translated and validated form of Fagerström Test for Nicotine Dependence for smoking and smokeless tobacco. The mean age of the tobacco users was 39.55 ± 15.57. Descriptive statistics including the mean, median, percentage, standard deviations and interquartile range were computed. Chi-square test, Fisher's exact test, univariate and bivariate logistic regression were used where needed. RESULTS: Nicotine dependence (moderate and severe) was found in 80% of smokeless tobacco users and 48% of smokers. Among the smokeless tobacco users, nicotine dependency was found to be more with increase in duration of tobacco use (AOR = 50.25, 95%CI = 3.51-718.62, p = 0.004), low socioeconomic status (AOR = 6.27, 95%CI = 1.30-30.31, p = 0.02), less number of tobacco packets used per day and tried to quit tobacco use in last 1 year. Among smokers nicotine dependency was found to be significantly higher with smoking more than 10 cigarettes per day (AOR = 7.14, 95% CI = 2.00-25.40, p = 0.002). CONCLUSIONS: The study concluded that level of nicotine dependence for both smoking and smokeless tobacco was high among the people visiting dental outreach programs. It is high time to develop a policy to control tobacco use along with creating tobacco cessation centers. Currently, tobacco control program is mostly focusing on smoking. However, it is also important to incorporate smokeless tobacco control at policy level.

Mitochondria-targeted antioxidant protects against irradiation-induced salivary gland hypofunction.

A severe consequence of radiation therapy in patients with head and neck cancer is persistent salivary gland hypofunction which causes xerostomia and oral infections. We previously showed that irradiation (IR) of salivary glands in mice triggers initial transient increases in mitochondrial reactive oxygen species (ROSmt), mitochondrial [Ca2+] ([Ca2+]mt), and activated caspase-3 in acinar cells. In contrast, loss of salivary secretion is persistent. Herein we assessed the role of ROSmt in radiation-induced irreversible loss of salivary gland function. We report that treatment of mice with the mitochondrial-targeted antioxidant, MitoTEMPO, resulted in almost complete protection of salivary gland secretion following either single (15 Gy) or fractionated (5 × 3 Gy) doses of irradiation. Salivary gland cells isolated from MitoTEMPO-treated, irradiated, mice displayed significant attenuation of the initial increases in ROSmt, ([Ca2+]mt, and activated caspase-3 as compared to cells from irradiated, but untreated, animals. Importantly, MitoTEMPO treatment prevented radiation-induced decrease in STIM1, consequently protecting store-operated Ca2+ entry which is critical for saliva secretion. Together, these findings identify the initial increase in ROSmt, that is induced by irradiation, as a critical driver of persistent salivary gland hypofunction. We suggest that the mitochondrially targeted antioxidant, MitoTEMPO, can be potentially important in preventing IR-induced salivary gland dysfunction.

STIM2 targets Orai1/STIM1 to the AKAP79 signaling complex and confers coupling of Ca2+ entry with NFAT1 activation.

The Orai1 channel is regulated by stromal interaction molecules STIM1 and STIM2 within endoplasmic reticulum (ER)-plasma membrane (PM) contact sites. Ca2+ signals generated by Orai1 activate Ca2+-dependent gene expression. When compared with STIM1, STIM2 is a weak activator of Orai1, but it has been suggested to have a unique role in nuclear factor of activated T cells 1 (NFAT1) activation triggered by Orai1-mediated Ca2+ entry. In this study, we examined the contribution of STIM2 in NFAT1 activation. We report that STIM2 recruitment of Orai1/STIM1 to ER-PM junctions in response to depletion of ER-Ca2+ promotes assembly of the channel with AKAP79 to form a signaling complex that couples Orai1 channel function to the activation of NFAT1. Knockdown of STIM2 expression had relatively little effect on Orai1/STIM1 clustering or local and global [Ca2+]i increases but significantly attenuated NFAT1 activation and assembly of Orai1 with AKAP79. STIM1ΔK, which lacks the PIP2-binding polybasic domain, was recruited to ER-PM junctions following ER-Ca2+ depletion by binding to Orai1 and caused local and global [Ca2+]i increases comparable to those induced by STIM1 activation of Orai1. However, in contrast to STIM1, STIM1ΔK induced less NFAT1 activation and attenuated the association of Orai1 with STIM2 and AKAP79. Orai1-AKAP79 interaction and NFAT1 activation were recovered by coexpressing STIM2 with STIM1ΔK. Replacing the PIP2-binding domain of STIM1 with that of STIM2 eliminated the requirement of STIM2 for NFAT1 activation. Together, these data demonstrate an important role for STIM2 in coupling Orai1-mediated Ca2+ influx to NFAT1 activation.

Cancer Registration in Nepal: Current Status and Way Forward.

Cancer registration is an organization for the systematic collection, storage, analysis, interpretation and reporting of data on subjects with cancer. Cancer Registry was initiated in 1995 and expanded as National Cancer Registry Program since 2003 by B.P. Koirala Memorial Cancer Hospital with the support of World Health Organization. National cancer registry program currently includes 12 hospital-based registries. First time in Nepal, B.P. Koirala Memorial Cancer Hospital piloted population-based cancer registry in 2013, which included 15 districts covering 25.8% of total population of Nepal. National cancer registry program is important to assure the quality of data from all the registries to ensure the availability of reliable and valid data of cancer cases. This will further help policymakers to develop preventive and control strategies against cancer. This paper reviews the current status of cancer registries in Nepal and discusses challenges and future perspectives related to national cancer registry program. National cancer registry should further include major hospitals in Nepal to give scientific information on cancer trends by community, provinces and regions and to analyze on survival of cancer cases. Keywords: cancer; national cancer registry program; Nepal.

Cross-talk between N-terminal and C-terminal domains in stromal interaction molecule 2 (STIM2) determines enhanced STIM2 sensitivity.

Store-operated Ca2+ entry (SOCE) is a ubiquitous pathway for Ca2+ influx across the plasma membrane (PM). SOCE is mediated by the endoplasmic reticulum (ER)-associated Ca2+-sensing proteins stromal interaction molecule 1 (STIM1) and STIM2, which transition into an active conformation in response to ER Ca2+ store depletion, thereby interacting with and gating PM-associated ORAI1 channels. Although structurally homologous, STIM1 and STIM2 generate distinct Ca2+ signatures in response to varying strengths of agonist stimulation. The physiological functions of these Ca2+ signatures, particularly under native conditions, remain unclear. To investigate the structural properties distinguishing STIM1 and STIM2 activation of ORAI1 channels under native conditions, here we used CRISPR/Cas9 to generate STIM1-/-, STIM2-/-, and STIM1/2-/- knockouts in HEK293 and colorectal HCT116 cells. We show that depending on cell type, STIM2 can significantly sustain SOCE in response to maximal store depletion. Utilizing the SOCE modifier 2-aminoethoxydiphenyl borate (2-APB), we demonstrate that 2-APB-activated store-independent Ca2+ entry is mediated exclusively by endogenous STIM2. Using variants that either stabilize or disrupt intramolecular interactions of STIM C termini, we show that the increased flexibility of the STIM2 C terminus contributes to its selective store-independent activation by 2-APB. However, STIM1 variants with enhanced flexibility in the C terminus failed to support its store-independent activation. STIM1/STIM2 chimeric constructs indicated that coordination between N-terminal sensitivity and C-terminal flexibility is required for specific store-independent STIM2 activation. Our results clarify the structural determinants underlying activation of specific STIM isoforms, insights that are potentially useful for isoform-selective drug targeting.

Tuning store-operated calcium entry to modulate Ca2+-dependent physiological processes.

The intracellular calcium signaling processes are tightly regulated to ensure the generation of calcium signals with the specific spatiotemporal characteristics required for regulating various cell functions. Compartmentalization of the molecular components involved in the generation of these signals at discrete intracellular sites ensures the signaling specificity and transduction fidelity of the signal for regulating downstream effector processes. Store-operated calcium entry (SOCE) is ubiquitously present in cells and is critical for essential cell functions in a variety of tissues. SOCE is mediated via plasma membrane Ca2+ channels that are activated when luminal [Ca2+] of the endoplasmic reticulum ([Ca2+]ER) is decreased. The ER-resident stromal interaction molecules, STIM1 and STIM2, respond to decreases in [Ca2+]ER by undergoing conformational changes that cause them to aggregate at the cell periphery in ER-plasma membrane (ER-PM) junctions. At these sites, STIM proteins recruit Orai1 channels and trigger their activation. Importantly, the two STIM proteins concertedly modulate Orai1 function as well as the sensitivity of SOCE to ER-Ca2+ store depletion. Another family of plasma membrane Ca2+ channels, known as the Transient Receptor Potential Canonical (TRPC) channels (TRPC1-7) also contribute to sustained [Ca2+]i elevation. Although Ca2+ signals generated by these channels overlap with those of Orai1, they regulate distinct functions in the cells. Importantly, STIM1 is also required for plasma membrane localization and activation of some TRPCs. In this review, we will discuss various molecular components and factors that govern the activation, regulation and modulation of the Ca2+ signal generated by Ca2+ entry pathways in response to depletion of ER-Ca2+ stores. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.

STIM2 Induces Activated Conformation of STIM1 to Control Orai1 Function in ER-PM Junctions.

Ca2+ entry mediated by the calcium channel, Orai1, provides critical Ca2+ signals that regulate cell function. The ER-Ca2+ sensor protein, STIM1, recruits and strongly activates Orai1 within ER-PM junctions. STIM2 is a poor activator of Orai1, and its physiological role is not well understood. Herein, we report a crucial function for STIM2 in inducing the activated conformation of STIM1. By using conformational sensors of STIM2 and STIM1, together with protein interaction and functional studies, we show that STIM2 is constitutively localized within ER-PM junctions in ER-Ca2+ store replete cells. Importantly, STIM2 traps STIM1 and triggers remodeling of STIM1 C terminus, causing STIM1/Orai1 coupling and enhancement of Orai1 function in cells with relatively high ER-[Ca2+]. The increase in Ca2+ entry controls Ca2+-dependent transcription factor, NFAT, activation at low [agonist]. Our findings reveal that STIM2 modulates STIM1/Orai1 function to tune the fidelity of receptor-evoked Ca2+ signaling and the physiological response of cells.

Radiation inhibits salivary gland function by promoting STIM1 cleavage by caspase-3 and loss of SOCE through a TRPM2-dependent pathway.

Store-operated Ca2+ entry (SOCE) is critical for salivary gland fluid secretion. We report that radiation treatment caused persistent salivary gland dysfunction by activating a TRPM2-dependent mitochondrial pathway, leading to caspase-3-mediated cleavage of stromal interaction molecule 1 (STIM1) and loss of SOCE. After irradiation, acinar cells from the submandibular glands of TRPM2+/+ , but not those from TRPM2-/- mice, displayed an increase in the concentrations of mitochondrial Ca2+ and reactive oxygen species, a decrease in mitochondrial membrane potential, and activation of caspase-3, which was associated with a sustained decrease in STIM1 abundance and attenuation of SOCE. In a salivary gland cell line, silencing the mitochondrial Ca2+ uniporter or caspase-3 or treatment with inhibitors of TRPM2 or caspase-3 prevented irradiation-induced loss of STIM1 and SOCE. Expression of exogenous STIM1 in the salivary glands of irradiated mice increased SOCE and fluid secretion. We suggest that targeting the mechanisms underlying the loss of STIM1 would be a potentially useful approach for preserving salivary gland function after radiation therapy.

Assembly of ER-PM Junctions: A Critical Determinant in the Regulation of SOCE and TRPC1.

Store-operated calcium entry (SOCE), a unique plasma membrane Ca2+ entry mechanism, is activated when ER-[Ca2+] is decreased. SOCE is mediated via the primary channel, Orai1, as well as others such as TRPC1. STIM1 and STIM2 are ER-Ca2+ sensor proteins that regulate Orai1 and TRPC1. SOCE requires assembly of STIM proteins with the plasma membrane channels which occurs within distinct regions in the cell that have been termed as endoplasmic reticulum (ER)-plasma membrane (PM) junctions. The PM and ER are in close proximity to each other within this region, which allows STIM1 in the ER to interact with and activate either Orai1 or TRPC1 in the plasma membrane. Activation and regulation of SOCE involves dynamic assembly of various components that are involved in mediating Ca2+ entry as well as those that determine the formation and stabilization of the junctions. These components include proteins in the cytosol, ER and PM, as well as lipids in the PM. Recent studies have also suggested that SOCE and its components are compartmentalized within ER-PM junctions and that this process might require remodeling of the plasma membrane lipids and reorganization of structural and scaffolding proteins. Such compartmentalization leads to the generation of spatially- and temporally-controlled Ca2+signals that are critical for regulating many downstream cellular functions.

Extracellular Adenosine Diphosphate Ribose Mobilizes Intracellular Ca2+ via Purinergic-Dependent Ca2+ Pathways in Rat Pulmonary Artery Smooth Muscle Cells.

BACKGROUND/AIMS: Adenosine diphosphate ribose (ADPR), a product of ß-NAD+ metabolism generated by the multifunctional enzyme CD38, is recognized as a novel signaling molecule. The catalytic site of CD38 orients extracellularly or intracellularly, capable of generating ADPR outside and inside the cells. CD38-dependent pathways have been characterized in pulmonary artery smooth muscle cells (PASMCs); however the physiological function of extracellular ADPR is unclear. METHODS: Ca2+ mobilizing and proliferative effects of extracellular ADPR were characterized and compared with the ATP-induced responses in rat PASMCs; and the expression of purinergic receptor (P2X and P2Y) subtypes were examined in pulmonary arteries. RESULTS: ADPR elicited concentration-dependent increase in [Ca2+]i with a fast transient and a sustained phase in PASMCs. The sustained phase was abolished by Ca2+ removal and inhibited by the non-selective cation channel blocker SKF-96365, but was unaffected by TRPM2 antagonists or nifedipine. The purinergic receptor (P2X) antagonist pyridoxal-phosphate-6-azophenyl-2', 4'-disulfonate inhibited partially the transient and the sustained Ca2+ response, while the P2(XY) inhibitor suramin and the phospholipase C inhibitor U73122 abolished the sustained Ca2+ influx. The P2Y1 antagonist MRS2179 had no effect on the response. By contrast, ATP and ADP activated Ca2+ response exhibited a high and a low affinity component, and the pharmacological profile of ATP-induced Ca2+ response was distinctive from that of ADPR. BrdU incorporation assay showed that ADPR caused significant inhibition whereas ATP caused slight stimulation of PASMC proliferation. RT-PCR analysis found that almost all P2X and P2Y subtypes are expressed in PAs. CONCLUSION: ADPR and ATP activate Ca2+ responses through different combinations of multiple purinergic receptor subtypes; and extracellular ADPR may exert an autocrine/paracrine action via purinergic receptors on PASMCs.

Malignant Neoplasm Burden in Nepal - Data from the Seven Major Cancer Service Hospitals for 2012.

In Nepal, while no population based cancer registry program exists to assess the incidence, prevalence, morbidity and mortality of cancer, at the national level a number of hospital based cancer registries are cooperating to provide relevant data. Seven major cancer diagnosis and treatment hospitals are involved, including the BP Koirala Memorial Cancer hospital, supported by WHO-Nepal since 2003. The present retrospective analysis of cancer patients of all age groups was conducted to assess the frequencies of different types of cancer presenting from January 1st to December 31st 2012. A total of 7,212 cancer cases were registered, the mean age of the patients being 51.9 years. The most prevalent age group in males was 60-64 yrs (13.6%), while in females it was 50-54 yrs (12.8%). The commonest forms of cancer in males were bronchus and lung (17.6%) followed by stomach (7.3%), larynx (5.2%) and non Hodgkins lymphoma (4.5%). In females, cervix uteri (19.1%) and breast (16.3%), were the top ranking cancer sites followed by bronchus and lung (10.2%), ovary (6.1%) and stomach (3.8%). The present data provide an update of the cancer burden in Nepal and highlight the relatively young age of breast and cervical cancer patients.

IP3-induced cytosolic and nuclear Ca2+ signals in HL-1 atrial myocytes: possible role of IP3 receptor subtypes.

HL-1 cells are the adult cardiac cell lines available that continuously divide while maintaining an atrial phenotype. Here we examined the expression and localization of inositol 1,4,5-trisphosphate receptor (IP(3)R) subtypes, and investigated how pattern of IP(3)-induced subcellular local Ca(2+) signaling is encoded by multiple IP(3)R subtypes in HL-1 cells. The type 1 IP(3)R (IP(3)R1) was expressed in the perinucleus with a diffuse pattern and the type 2 IP(3)R (IP(3)R2) was expressed in the cytosol with a punctate distribution. Extracellular ATP (1 mM) elicited transient intracellular Ca(2+) releases accompanied by a Ca(2+) oscillation, which was eliminated by the blocker of IP(3)Rs, 2-APB, and attenuated by ryanodine. Direct introduction of IP(3) into the permeabilized cells induced Ca(2+) transients with Ca(2+) oscillations at [Symbol: see text] 20 muM of IP(3), which was removed by the inhibition of IP(3)Rs using 2-APB and heparin. IP(3)-induced local Ca(2+) transients contained two distinct time courses: a rapid oscillation and a monophasic Ca(2+) transient. The magnitude of Ca(2+) oscillation was significantly larger in the cytosol than in the nucleus, while the monophasic Ca(2+) transient was more pronounced in the nucleus. These results provide evidence for the molecular and functional expression of IP(3)R1 and IP(3)R2 in HL-1 cells, and suggest that such distinct local Ca(2+) signaling may be correlated with the punctate distribution of IP(3)R2s in the cytosol and the diffuse localization of IP(3)R1 in the peri-nucleus.