Insulin secretion

Nitric oxide (NO) is a gas that serves as a ubiquitous signaling molecule participating in physiological activities of various organ systems. Nitric oxide is produced in the endocrine pancreas and contributes to synthesis and secretion of insulin. The potential role of NO in insulin secretion is disputable – both stimulatory and inhibitory effects have been reported. Available data indicate that effects of NO critically depend on its concentration. Different isoforms of NO synthase (NOS) control this and have the potential to decrease or increase insulin secretion. In this review, the role of NO in insulin secretion as well as the possible reasons for discrepant findings are discussed. A better understanding of the role of NO system in the regulation of insulin secretion may facilitate the development of new therapeutic strategies in the management of diabetes

Energy Consumption and Modeling of output energy with Multilayer Feed-Forward Neural Network for Corn Silage in Iran

In this study, various Artificial Neural Networks (ANNs) were developed to estimate the output energy for corn silage production in Esfahan province, Iran. For this purpose, the data on 65 corn silage production farms in the Esfahan province, were collected and analyzed. The results indicated that total energy input for corn silage production was about 83126 MJ ha–1; machinery (with 38.8 %) and chemical fertilizer (with 24.5 %) were amongst the highest energy inputs for corn silage production. The developed ANN was a multilayer perceptron (MLP) with eight neurons in the input layer (human power, machinery, diesel fuel, chemical fertilizer, water for irrigation, seed, farm manure and pesticides ), one, two, three, four and five hidden layer(s) of various numbers of neurons and one neuron (output energy) in the output layer. The results of ANNs analyze showed that the (8-5-5-1)-MLP, namely, a network having five neurons in the first and second hidden layer was the best-suited model estimating the corn silage output energy. For this topology, MAB, MAE, RMSE and R2 were 0.109, 0.001, 0.0464 and 98%, respectively. The sensitivity analysis of input parameters on output showed that diesel fuel and seeds had the highest and lowest sensitivity on output energy with 0.0984 and 0.0386, respectively. The ANN approach appears to be a suitable method for modeling output energy, fuel consumption, CO2 emission, yield, and energy consumption based on social and technical parameters. This method would open new doors to advances in agriculture and modeling

Ovariectomized rat model of osteoporosis

Osteoporosis affects about 200 million people worldwide and is a silent disease until a fracture occurs. Management of osteoporosis is still a challenge that warrants further studies for establishing new prevention strategies and more effective treatment modalities. For this purpose, animal models of osteoporosis are appropriate tools, of which the ovariectomized rat model is the most commonly used. The aim of this study is to provide a 4-step guideline for inducing a rat model of osteoporosis by ovariectomy (OVX): (1) selection of the rat strain, (2) choosing the appropriate age of rats at the time of OVX, (3) selection of an appropriate surgical method and verification of OVX, and (4) evaluation of OVX-induced osteoporosis. This review of literature shows that (i) Sprague-Dawley and Wistar rats are the most common strains used, both responding similarly to OVX; (ii) six months of age appears to be the best time for inducing OVX; (iii) dorsolateral skin incision is an appropriate choice for initiating OVX; and (iv) the success of OVX can be verified 1-3 weeks after surgery, following cessation of the regular estrus cycles, decreased estradiol, progesterone, and uterine weight as well as increased LH and FSH levels. Current data shows that the responses of trabecular bones of proximal tibia, lumbar vertebrae and femur to OVX are similar to those in humans; however, for short-term studies, proximal tibia is recommended. Osteoporosis in rats is verified by lower bone mineral density and lower trabecular number and thickness as well as higher trabecular separation, changes that are observed at 14, 30, and 60 days post-OVX in proximal tibia, lumbar vertebrae and femur, respectively

Inorganic nitrate, a natural anti-obesity agent

Evidence for potential effects of inorganic nitrate (NO3) on body weight is limited to inconsistent findings of animal experiments. In this systematic review and meta-analysis, we aimed to quantify the overall effect of inorganic NO3, administered via drinking water, on body weight gain in rats. We searched PubMed, Scopus, and Embase databases, and the reference lists of published papers. Experiments on male rats, reported data on body weight in NO3-treated animals and controls, were included for quality assessment, meta-analyses, subgroup analyses, and meta-regressions. Of 173 initially obtained studies, 11 were eligible to be included in the analyses, which covered the years 2004 to 2019 and included a total of 43 intervention (n=395) and 43 control (n=395) arms. Overall, the final body weights were significantly lower in the NO3-supplemented groups compared to controls (WMD= –16.8 g, 95 % CI= –27.38, –6.24; P=0.002). Doses of NO3 higher than the median (> 72.94 mg L-1 d-1) and longer NO3 exposure (> 8 weeks) resulted in greater mean differences (WMD= –31.92 g, 95 % CI= –52.90, –10.94 and WMD= –23.16 g, 95 % CI= –35.64, –10.68 g). After exclusion of experiments using high doses of NO3 (> 400 mg L-1 d-1), the overall mean differences in body weights between the groups decreased by approximately 37 % but remained statistically significant (WMD= –10.11 g, 95 % CI= –19.04, –1.19, P=0.026). Mean changes in body weight were affected by age, baseline values in body weight, and the duration of the studies. These preliminary experimental findings strongly support the hypothesis that NO3 can be considered as a natural anti-obesity agent

Evaluation of antioxidant properties of button mushroom in different harvest and morphological stages

This study was conducted to test the impact of flush number, mushroom size and cap openness on phenolic and flavonoid contents and antioxidant properties of button mushroom (Agaricus bisporus). Results showed that all tested facrors had a significant effect on dry matter and antioxidant properties of mushroom. The first flush had the highest dry matter in comparison with second and third flushs. Antioxiant activity and flavonoid content of mushrooms in second flush was significantly more than others but for phenol content, the first flush was the best. Surprisingly, the lowest antioxidant activity, phenol, and flavonoid contents were obseved in third flush. The highest antioxidant activity, phenol, and flavonoid content were recorded in large size, medium size, and small size of mushrooms, respectively. Cap of the mushroom showed significantly more antioxidant properties and flavanoid content, however, the phenol in stipe part was more than the cap part. Closed-cap mushrooms had significantly more dry matter and total phenol content, while no significant difference was seen in antioxidant activity and flavonoid compounds. In summary, mushrooms produced in third flush have lower dietary quality than first and second flushes, cap part of button mushroom was better than stipe and total antioxidant capacity was not affected by cap opening

Effect of long-term inorganic nitrate administration on myocardial ischemia-reperfusion injury in ovariectomized rats

Introduction: Menopause is associated with reduced nitric oxide (NO) bioavailability and lower tolerance against myocardial ischemia-reperfusion (IR) injury. This study investigated whether long-term nitrate administration provides resistance against myocardial IR injury in ovariectomized (OVX) rats.Method: After ovariectomy, female rats were assigned to the OVX and the OVX + nitrate groups (n = 14/group); the latter group consumed nitrate (100 mg/L) for 9 months. At month 9, each group was divided into two subgroups (n = 7/subgroup), of which one subgroup was exposed to myocardial IR (IR+ hearts) and the other was not exposed (IR− hearts). The hearts of rats were isolated, and NO metabolite (NOx), oxidative stress indices, and mRNA expressions of endothelial (eNOS), inducible (iNOS), and neuronal (nNOS) NO synthases, as well as markers of apoptosis, were measured in the IR− and IR+ hearts. In the IR+ hearts, cardiac function indices (CFI) and the infarct size were also measured.Results: Nitrate increased catalase activity (97%) and eNOS expression (2.94-fold) in the IR− hearts. In the IR+ hearts, nitrate reduced left ventricular (LV) end-diastolic pressure (11.6%) and infarct size (26.2%) and increased recovery of LV developed pressure (44.0%) and peak rate of positive (28.9%) and negative (15.4%) changes in LV pressure. In addition, in the IR+ hearts, nitrate increased eNOS and B-cell lymphoma-2 (Bcl-2) as well as decreased iNOS, Bcl-2 associated X protein (Bax), caspase-3, caspase-8, caspase-9, and tumor necrosis factor-α (TNF-α) expression. Nitrate increased total antioxidant capacity (TAC) and catalase (CAT) activity and decreased malondialdehyde (MDA) levels at month nine in serum and IR+ hearts.Conclusion: The favorable effects of nitrate against IR injury were associated with higher eNOS and Bcl-2 expression, CAT activity, TAC, and lower iNOS, Bax, caspase-3, caspase-8, caspase-9 and TNF-α expression, and MDA in the heart tissue. Nitrate preconditioning alleviated IR-induced myocardial injury in OVX rats; this effect was associated with eNOS upregulation before IR and the blunting of OVX-induced eNOS downregulation, iNOS upregulation, apoptosis, and oxidative stress in heart tissue after IR

Evaluation of pulmonary dysfunction of workers exposed to styrene vapors in a plastic injection industry

زمینه و اهداف: استایرن از جمله مواد شیمیایی آلی فرار می‌باشد که مواجهه تنفسی با بخارات آن باعث ایجاد عوارض سلامتی مانند اختلالات تنفسی می‌شود. لذا هدف این مطالعه بررسی اختلال عملکرد ریوی کارگران یک صنعت تزریق پلاستیک با بخارات استایرن است. مواد و روش‌ها: مطالعه حاضر به‌صورت کوهورت-گذشته نگر، در یک صنعت تزریق پلاستیک انجام گرفت. پنجاه نفر از کارکنان خطوط تولید به‌ عنوان گروه مواجهه و 20 نفر از کارکنان اداری به‌ عنوان گروه مواجهه نیافته انتخاب شدند. ابتدا غلظت محیطی استایرن اندازه­گیری شد. سپس  پارامترهای ریوی کارکنان شامل حجم بازدمی اجباری در ثانیه اول (FEV1)، ظرفیت حیاتی اجباری و پرفشار (FVC)، کسر ظرفیت حیاتی خروجی در ثانیه اول بازدم (FEV1/FVC) و حداکثر جریان بازدمی (PEF) در دو نوبت "ابتدای نوبت‌کاری" و "بعد از خاتمه کار" بدست آمد.  علائم تنفسی این کارکنان با استفاده از پرسشنامه انجمن متخصصین قفسه صدری آمریکا (ATS)، بررسی شد. کلیه مفاد بیانیه هلسینکی در این مطالعه رعایت شد. یافته‌ها: نتایج به‌دست‌آمده اختلاف معناداری را در برخی از پارامترهای ظرفیت ریوی شاملFEV1 و FEV1/FVC در ابتدا و انتهای نوبت‌کاری نشان داد (05/0P <). علائم تنفسی شامل سرفه، سوزش بینی و گلو، گرفتگی صدا و خس‌خس سینه بین گروه مواجهه یافته نسبت به گروه مواجهه نیافته به‌صورت معناداری بیشتر بود (05/0P<). نتیجه‌گیری: نتایج نشان می‌دهد مواجهه با استایرن ارتباط معناداری با کاهش ظرفیت ریوی و بروز علائم تنفسی دارد.Background and Aims: As a volatile organic chemical, respiratory exposure to  styrene vapors causes health consequences including respiratory disorders. Therefore, the aim of this study was to investigate the pulmonary dysfunction of workers in a plastic injection industry polluted with styrene vapors.  Materials and Methods: The present study was a retrospective cohort in a plastic injection industry. Fifty production line employees were selected as the exposure group and 20 as the non-exposure control group. First, the environmental concentration of styrene was measured. Then the pulmonary parameters of the staff including the forced expiratory volume in the first second (FEV1), the forced and high-pressure vital capacity (FVC), the deduction of the critical output capacity in the first second of exhalation (FEV1 / FVC) and the maximum expiratory flow (PEF) at the “beginning of the shift” and "after completion" were obtained. Respiratory symptoms of these employees were assessed using a questionnaire of the American Chest Specialists Association (ATS). All the provisions of the Helsinki Declaration were observed in this study.  Results: The results showed significant differences in some pulmonary capacity parameters including FEV1 and FEV1 / FVC at the beginning and end of the work shift (p <0.05). Respiratory symptoms including cough, burning nose and throat, hoarseness and wheezing were significantly higher in the exposed group than in the non-exposed group (p <0.05).  Conclusion: The results showed that exposure to styrene is significantly associated with decreased pulmonary capacity and respiratory symptoms