asghar ghasemi

This study aims to investigate the long-term effects of different doses of nitrate on the lipid profile in male rats.

Male Wistar rats (n = 60) were assigned to 6 groups (n = 10 per group). The control group received drinking water, and 5 treatment groups received nitrate at doses of 50, 100, 150, 250, and 500 mg/L for 6 months. Nitric oxide (NO) metabolite levels (NOx) were determined at months 0 and 6. Lipid profile [cholesterol, triglyceride (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL)] in the serum was measured at months 0, 3, and 6.

Nitrate administration for 6 months (at doses of 50, 100, 150, 250, and 500 mg/L) could increase serum NOX levels by 29.5% (P = 0.0115), 39.6% (P = 0.0002), 65.2% (P < 0.0001), 91.4% (P < 0.0001), and 181.6% (P < 0.0001), respectively. Nitrate administration for 6 months (at doses of 50, 100, and 150 mg/L) decreased serum TG [7.8% (P = 0.0508), 7.4% (P = 0.0654), and 8.3% (P = 0.0331)] and cholesterol [12.7% (P = 0.0066), 15.2% (P = 0.0009), and 15.2% (P = 0.0009)] levels. In addition, it increased serum HDL at doses of 50, 100, and 250 mg/L [24.4% (P = 0.0005), 13.9% (P= 0.0910), and 17.5% (P = 0.0172)], while it had no significant effect on serum LDL levels in comparison to the control group.

  Long-term nitrate administration at low doses (50‒150 mg/L) prevented dyslipidemia (improved lipid profile) in male rats. These beneficial effects of nitrate can be mainly due to increased serum levels of NO metabolites.

We aimed to track longitudinal changes of glycemic status in subjects with prediabetes (Pre-DM) in relation to their baseline levels of systemic nitric oxide (NO) production [i.e., measured as serum NO metabolites (NOx), crude and body weight (BW)-adjusted NOx to creatinine ratio (NOx-to-Cr)] over 9 years.

This cohort study included 541 middle-aged Iranian men and women with Pre-DM, recruited in 2006-2008 and followed up to 2015-2017. The colorimetric Griess method was used to measure serum NOx concentration. Multinomial logistic regression analyses estimated the odds ratios (OR) of Pre-DM regression and progression across tertiles (tertile 3 vs. tertile 1 and tertile 2) of serum NOx, crude, and BW-adjusted NOx-to-Cr ratio.

Participants who regressed to normoglycemia (NG) had a higher BW-adjusted NOx-to-Cr ratio than those who developed type 2 diabetes (T2D) or those who remained Pre-DM (0.52±0.34 vs. 0.43±0.25 and 0.48±0.29, P=0.023). Higher BW-adjusted NOx-to-Cr increased chance of returning to NG (OR=2.05, 95% CI= 0.98-4.32, P=0.058) and decreased levels of 2h-serum glucose over time (Ptime×group=0.025), as well as the decreased overall mean of fasting (106, 95% CI=103-109 vs. 110, 95% CI=108-112 mg/dL, P=0.008) and 2h-serum glucose (153, 95% CI=146-159 vs. 163, 95% CI=158-168 mg/dL, P=0.018).

A higher endogenous NO production (i.e., indirectly measured by BW- and Cradjusted serum NOx concentration) in Pre-DM subjects is associated with the chance of returning to NG.

Nitrite, a nitric oxide (NO) donor, increases insulin secretion from pancreatic islets and has positive metabolic effects in type 2 diabetes (T2D). Here, we test the hypothesis of whether nitrite-induced insulin secretion is due to blunting of diabetes-induced oxidative stress in the islets.

T2D was created in male rats using a combination of streptozotocin at 25 mg/kg and a high-fat diet. Wistar rats were assigned to 3 groups (n=6 in each group), including control, T2D, and T2D+nitrite; the latter group consumed drinking water containing sodium nitrite (50 mg/l) for eight weeks. At the end of the study, mRNA levels of NADPH oxidase (Nox1, 2, 3, and 4), superoxide dismutase (SOD1, 2, and 3), glutathione peroxides (GPX1 and 7), glutathione reductase (GR), catalase, thioredoxin (TXN1 and 2), and thioredoxin reductase (TXNRD1) were measured in the isolated pancreatic islets. 

In the islets of diabetic rats, mRNA expressions of Nox1, 2, and 4 were higher, whereas expressions of SOD1, 2, catalase, GPX1, 7, GR, and TXN1 were lower than controls. Nitrite significantly (all P-values<0.05) decreased gene expression of Nox1 (0.39-fold) and Nox4 (0.23-fold) and increased gene expression of SOD1 (2.2-fold), SOD2 (2.8-fold), catalase (2.7-fold), GPX1 (2.2-fold), GPX7 (6.0-fold), GR (3.0-fold), TXN1 (2.1-fold), and TXNRD1 (2.3-fold) in diabetic rats. 

Nitrite decreased oxidative stress in isolated pancreatic islets of rats with T2D by suppressing oxidants and augmenting anti-oxidants. These findings favor the notion that nitrite-induced insulin secretion is partially due to decreased oxidative stress.

Scientific publishing, with about 350-year historical background, has played a central role in advancing science by disseminating new findings, generalizing accepted theories, and sharing novel ideas. The number of scientific journals has exponentially grown from 10 at the end of the 17th century to 100,000 at the end of the 20th century. The publishing landscape has dramatically changed over time from printed journals to online publishing. Although scientific publishing was initially non-commercial, it has become a profitable industry with a significant global financial turnover, reaching $28 billion in annual revenue before the COVID-19 pandemic. However, scientific publishing has encountered several challenges and is suffering from unethical practices and some negative phenomena, like publish-or-perish, driven by the need to survive or get a promotion in academia. Developing a global landscape with collaborative non-commercial journals and platforms is a primary proposed model for the future of scientific publishing. Here, we provide a brief history of the foundation and development of scientific journals and their evolution over time. Furthermore, current challenges and future perspectives of scientific publishing are discussed.

High prevalence of liver disorders has been observed in postmenopausal women. This study aims at determining the effects of long-term, low-dose nitrate administration on serum levels of liver enzymes, including aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) in ovariectomized rats. 

 Female Wistar rats were divided into three groups (n=10/group): control, ovariectomized, and ovariectomi zed+nitrate. The ovariectomized model (ovariectomy) was induced in 6-month-old female rats using the two-dorsolateral skin incision method. The control and ovariectomized rats received drinking water, and the ovariectomized+nitrate rats received sodium nitrate (100 mg/L in drinking water) for nine months. Body weight, food intake, and water consumption were measured in all the groups at the start (month 0, the beginning of sodium nitrate administration) and end of the study (month 9, the end of sodium nitrate administration). Serum levels of AST, ALP, and ALT were measured every month.

 Nitrate administration decreased body weight in the ovariectomized group at the end of the study (6.9%, P = 0.004) but did not affect water consumption and food intake. At the end of the study, the ovariectomized rats had increased serum levels of AST (21.1%, P<0.001), ALP (22.8%, P=0.004), and ALT (31.3%, P<0.001). Nitrate administration decreased serum levels of ALT (9.4%, P=0.029), AST (6.7%, P=0.012), and ALP (13.1%, P=0.001) over the period of the study. 

 Long-term, low-dose nitrate administration improved liver function in the ovariectomized rats.

A higher prevalence of cardiovascular disorders has been observed in women after menopause. This study aimed to determine the long-term effects of ovariectomy on hemodynamic functions and the level of nitric oxide metabolites (NOx) in the heart tissue of ovariectomized rats.

Fourteen female Wistar rats were divided into two groups (n=7 in each group) of control and ovariectomized (OVX). OVX rat model was induced using the two dorsolateral skin incision method. Cardiac hemodynamic function indices, including the left ventricular developed pressure (LVDP), peak rate of positive changes in the left ventricular pressure (+dp/dt), and peak rate of negative changes in the left ventricular pressure (-dp/dt) were measured at the time of systole in hearts after 11 months of the ovariectomy. Serum and left ventricular levels of NOx were measured at the end of the study.

At the end of the study, OVX rats had lower LVDP (19%, P=0.001), +dp/dt (30%, P<0.001) and -dp/dt (23%, P=0.004) than control group. In addition, the OVX group had lower serum NOx levels (30%, P=0.021) compared to the control group; heart tissue NOx was also lower by 31% in the OVX rats, but it was not statistically significant (P=0.056).

Long-term ovariectomy disrupts cardiac hemodynamic function in ovariectomized rats, which is associated with decreased NOx levels in serum. Practical Implications. Our findings indicated impaired cardiac function following long-term estrogen deficiency in OVX rats. These results can be used to prevent and treat the cardiovascular disease in post-menopausal women. However, these results need to be confirmed in humans.

The literature review is integral to the research process, from developing research ideas to disseminating findings. It involves explaining, interpreting, and summarizing published materials around a topic to elaborate a research hypothesis/question, synthesize new concepts, identify knowledge gaps, develop new theories, and identify new research directions. Compelling reading and processing of the literature (i.e., analyzing and synthesizing) and actual writing of the literature (verbal or non-verbal output, e.g., tables and figures) are essential stages of an effective literature review. This article provides a practical guide to conducting an effective literature review. In addition, literature search and evaluation are also briefly discussed.

As a nitric oxide (NO) donor, nitrate administration improves renal function in male animals. This study aims to determine the effects of chronic administration of different doses of nitrate on kidney function in normal adult female rats by measuring serum urea and creatinine and assessing the estimated glomerular filtration rate (eGFR).

Two-month old female Wistar rats were divided into six groups (n=10/group): the control group received tap water, and five nitrate-treated groups received water containing 50, 100, 150, 250, and 500 mg/L sodium nitrate in their drinking water for six months. At the end of the study, body weight, serum urea, and serum creatinine were measured, and eGFR was calculated.

Serum urea levels decreased by 16.9% (P=0.037) at dose 100 mg/L and increased by 15% (P=0.064) and 24.7% (P=0.003) at doses 250 and 500 mg/L, respectively, after nitrate administration. Serum creatinine levels decreased only at dose 100 mg/L by 16.3% (P=0.002) after nitrate administration. Moreover, eGFR increased at dose 100 mg/L (11.5%, P=0.046), decreased at doses 250 (13.8%, P=0.018) and 500 (16.9%, P=0.004) mg/L, and remained constant at doses 50 and 150 mg/L after nitrate administration.

Chronic nitrate administration exerted multiphasic effects on renal function in female rats; i.e., the low dose had no effect, the intermediate dose had a protective effect, and the high dose had detrimental effects on renal function.

Epigenetic alterations such as DNA methylation are known as the main cause of different types of cancers through inactivation of tumor suppressor genes, especially thyroid cancer. Identification of novel and effective markers are important in diagnosis and prevention of thyroid cancer. In the present study, the expression and methylation of Solute carrier family 5 member 8 (SLC5A8) in Papillary Thyroid Carcinoma (PTC) in comparison to multinodular goiter (MNG) have been studied.

Overall, 41 patients with PTC and 36 patients affected by MNG were recruitedfrom four hospitals in Tehran and Qazvin, Iran in 2018. Thyroid tissues were obtained during thyroidectomy. RNA and DNA were extracted from thyroid tissues. Quantitative RT-PCR assay was performed for determining the mRNA level of SLC5A8while Methylation-Sensitive High-Resolution Methylation was applied for assessing the methylation status.

Methylation status of three regions composed of 52 CpG islands in the promoter of SLC5A8gene was studied by HRM assay. SLC5A8level in PTC tissues was significantly downregulated in average 0.4 fold in comparisonwith MNG tissues (P=0.05). The aberrant methylation of SLC5A8(b) region was remarkably different in PTC and MNG cases. The promoter methylation of SLC5A8(c) was significantly related to BRAFmutations and vascular invasion in PTC patients.

The aberrant promoter hyper methylation of SLC5A8 was related to aggressive PTC. Therefore, there is some evidence to support the hypothesis that SLC5A8could be a paly important role in the develop-ment of PTC.

Getting feedback from the journals’ editorial office upon the peer-review process, revising the manuscript, and responding to reviewers’ comments are the essential parts of scientific publishing. The process of revising seems cumbersome and time-consuming as authors must be engaged probably with many comments and requested changes. Authors are advised to approach the reviewer as a consultant rather than an adversary. They should carefully read and understand comments and then decide how to proceed with each requested change/suggestion. In the case of serious disagreement with reviewer comments or misunderstanding, authors can defer the issue to the editor. Preparing a scientific and well-organized "response to reviews" and the revised version of the manuscript can increase the chance of acceptance. Here, we provide a practical guide on dealing with different types of comments (i.e., minor or major revisions, conflicting comments, or those that authors disagree with or cannot adhere to) and how to craft a response to reviews. We also provide the dos and don'ts for making a successful revision.

Despite the higher prevalence of kidney dysfunction in females, the effects of nitrate have mainly been studied in males. This study aimed to determine the effects of long-term sodium nitrate administration on kidney function in normal adult female rats by assessing estimated Glomerular Filtration Rate (eGFR), serum urea, and serum creatinine.

Female Wistar rats were divided into two groups (n = 10 per group). The control group received tap water, and the nitrate group received tap water containing 100 mg/L sodium nitrate for nine months. Bodyweight, serum urea, and serum creatinine were measured at the beginning and end of the study, and eGFR was calculated. The nitric oxide metabolites (NOx) levels were also measured at the end of the study in serum and kidney tissue.

The body weight, serum urea, and creatinine levels of rats in the control group were significantly higher, and eGFR was significantly lower at the end of the study compared to the beginning of the study. Nitrate administration for nine months prevented increases in body weight, serum urea, and creatinine and decreases in eGFR. Nitrate-treated female rats also had higher NOx levels in serum and kidney tissue.

Nitrate administration improved kidney function in female normal adult rats. These beneficial effects may be associated with increased serum and kidney levels of NOx.

Euthanasia is used to define ending an animal's life in a way that results in rapid anesthesia and death without pain or distress. One of the most common methods of performing euthanasia in rats is the administration of carbon dioxide (CO2). The aim of this study was to review the available practical guidelines for inducing euthanasia in rats by administrating CO2.

This review study was conducted by searching in international databases, including PubMed, Google Scholar, and Science Direct, using Euthanasia, CO2, and Rats as keywords.

Euthanasia of rat using CO2 is a relatively simple, common, rapid, practical and economical method and does not require advanced apparatus or very expert personnel. For doing euthanasia, parameters including the method of CO2 administration, characteristics of CO2 chamber, concentration and flow rate of CO2 administration, duration of euthanasia, euthanasia approval, and disposal of animal carcasses after euthanasia should be considered.

According to the overview of the available practical guidelines, a CO2 flow rate of 5.6 L/min is recommended for a standard cage (height, width, and length, 25.4, 22.86, and 48.26 cm, respectively) with a volume of 28 L, which is suitable for two rats. This CO2 flow should be maintained for 2-5 minutes to induce anesthesia and death and should be continued for at least one minute after observing death signs including lack of respiration and faded eye color.

 Nitric oxide (NO) plays a key role in thyroid function regulation through the inhibition of iodide (I) uptake at the thyroidal sodium-iodide symporter (NIS) and impacts on the thyroid vascularity and blood flow.

 This study aimed to evaluate the association between serum NO metabolites (NOx) and thyroid-stimulating hormone (TSH), free thyroxin (FT4), and anti-thyroid peroxidase (TPOAb) changes. Also, it aimed at evaluating the correlation between serum NOx and the incidence of clinical hypothyroidism, characterized by elevated TSH level and decreased FT4 concentration, and subclinical hypothyroidism, characterized by mildly elevated TSH level despite FT4 concentration within the normal range, over three years of follow-up.

 This study included 1,137 participants of the Tehran Thyroid study (TTS), aged > 20 years old, for whom data on serum TSH, FT4, and TPOAb in the third and fourth phases, and serum NOx in the third phase were available. Changes in TSH (ΔTSH), FT4 (ΔFT4), and TPOAb (ΔTPO) between the third and fourth phases were calculated, and the associations between serum NOx and ΔTSH, ΔFT4, and ΔTPOAb were assessed after multivariable adjustment using linear regression analysis.

 No significant association was found between serum NOx and ΔTSH, ΔFT4, and ΔTPOAb after the multivariable adjustment; neither was any observed in TPOAb split groups after multivariable adjustment. No significant association was found between serum NOx tertiles and clinical and subclinical hypothyroidism incidence in the fourth phase of TTS.

 There was no association between serum NOx levels and changes in TSH, FT4, and TPOAb and clinical and subclinical hypothyroidism incidence.

A cover (covering) letter is a brief business letter introducing the scientific work alongside the submission process of a manuscript and is required by most scientific peer-review journals. A typical cover letter includes the name of the editor and the journal, date of submission, the characteristics of the manuscript, the importance of the work and its relevance to prospective audiences, declarations such as author agreements, conflicts of interest statement, funding source (s), and ethical statements. The letter also includes the contact information of the corresponding author (s) and may also include suggestions of potential reviewers. Spending enough time to draft an informative, comprehensive, and concise cover letter is quite worthwhile; a poorly drafted one would not persuade the editor that the submitted work is fit for publication and may lead to immediate rejection. Here, we provide a practical guide to draft a well-written, concise, and professional cover letter for a scientific medical paper.

Publishing in peer-reviewed high-quality journals is a gold standard method for disseminating scientific work. Choosing the right journal is one of the most important and difficult aspects of publishing research results. Submitting to an inappropriate journal is one of the most common reasons for fast rejection of manuscripts, resulting in time wasted by the authors and journals’ editors. Here, we discuss important factors that should be considered for choosing the right journal to get your work published successfully and effectively. The most important factors for journal targeting are: (1) The journal’s characteristics, including its scientific prestige, performance, publishing model, acceptance possibility, and specialty; (2) the manuscript’s characteristics, including its relevance to the journal’s aim and scope, its intrinsic value, meaning the novelty of the research, soundness of the methodology, potential impact in the field, and its implication; and (3) authors’ priorities and limitations.

Thyroid cancer is the fourth most common cancer in the world. Papillary thyroid carcinoma (PTC) accounts for 80% of all types of thyroid neoplasm. Epigenetic alterations such as DNA methylation are known as the main cause of different types of cancers through inactivation of tumor suppressor genes.

In the present study, the expression and methylation of suggested gene namely nucleolar protein 4 (NOL4) in PTC in comparison to multi nodular goiter (MNG) have been studied.

Forty-one patients with PTC and 38 patients affected by MNG were recruited. Thyroid tissues were obtained during thyroidectomy. RNA and DNA were extracted from thyroid tissues. Quantitative RT-PCR assay was performed for determining the mRNA level of NOL4 while methylation-sensitive high resolution methylation was applied for assessing the methylation status with designing six pairs primers for six regions on gene promoter which were named from NOL4 (a) to NOL4 (f).

Methylation assessment of 81 CpG islands in the promoter region of NOL4 gene revealed that NOL4 (f), the nearest region to the start codon, was significantly hypermethylated in PTC cases compared to MNG cases. NOL4 level in PTC cases in comparison with MNG cases were downregulated. The methylation status and mRNA level of NOL4 (f) were associated with age of diagnosis (Age of the patient at the time of diagnosis), lymph node metastasis, and advanced stages of disease.

These data suggested an aberrant promoter hyper-methylation of NOL4 in PTC cases may be linked with its downregulation. Therefore, NOL4 gene can be proposed as a potential tumor suppressor gene in PTC tissues.

Liver disorders in patients with type 2 diabetes (T2D) are mostly associated with higher serum levels of liver enzymes. This study aimed to investigate the effect of nitrate administration on the serum levels of alanine amino transferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in rats with T2D.

In this study, 24 male Wistar rats were divided into four groups: control, control+nitrate, diabetes, and diabetes+nitrate. T2D was induced using a combination of high-fat diet and injection of low-dose streptozotocin (30 mg/kg). The rats in the nitrate-treated groups received sodium nitrate (100 mg/L in drinking water) for six months. The serum levels of ALT, AST, and ALP were measured at the beginning of the study and at three and six months after nitrate administration.

Diabetic rats showed increased levels of ALT, AST, and ALP in the serum at six months. Nitrate decreased the serum level of ALT by 17.6% (65.7±4.8 vs. 55.8±2.3 UI/L; P=0.0659), AST by 52.2% (161.3±13.3 vs. 106.0±6.1 UI/L; P<0.0001), and ALP by 15.1% (606.2±35.5 vs. 514.4±12.6 UI/L; P=0.0339) within six months.

Long-term and low-dose nitrate administration improved the liver function of rats with T2D, as reflected by the reduced serum levels of ALT, AST, and ALP.

Thyroid hormones play an important role in normal function of liver and hyperthyroidism can cause liver dysfunction. Thyroid hormones affect nitric oxide (NO)-producing enzymes in liver. The aim of this study is to investigate effects of hyperthyroidism on protein levels of three isoforms of NO synthase (NOS) enzymes, including endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS) in the liver of male rats.

Twelve male Wistar rats were divided into the hyperthyroid and the control groups. Hyperthyroidism was induced by administration of 12 mg/L of levothyroxine in the drinking water of rats for a period of 21 days. NO metabolites (i.e. nitrate+nitrite or NOx) concentrations in the serum and liver as well as iNOS, eNOS, and nNOS protein levels in the liver tissue were measured on day 21.

Serum levels of free thyroxine and total thyroxine were significantly higher, whereas that of the thyroid stimulating hormone (TSH) was significantly lower in rats with hyperthyroidism. Compared to controls, NOx levels were significantly higher in the serum (46%) and liver tissue (70%) of rats with hyperthyroidism. Hyperthyroidism decreased protein levels of eNOS (31%, P=0.006) and increased protein levels of iNOS (26%, P=0.020) but had no effect on nNOS in the liver.

Hyperthyroidism changed levels of NO-producing enzymes liver, indicating that dysfunction of NO system may contribute to the pathophysiology of hyperthyroidism.

Citation, the act of properly referring to others’ ideas, thoughts, or concepts, is a common and critical practice in scientific writing. Citations are used to give credit to own work, to support an argument, to acknowledge others’ work, to distinguish other authors’ ideas from one’s work, and to direct readers to sources of information. A good citation adds to the scientific prestige of the paper and makes it more valuable to the reader. The citation has three basic elements: quoting from others, an in-text reference to the source, and bibliographic details of the source. Beyond technical skills, the citation needs an in-depth knowledge of the field and should follow basic rules, including the selection of relevant and valid sources, stating information/facts from others’ work, and referring to others’ work accurately and ethically. Several systems and styles are used to cite scientific sources; however, the most commonly used systems in medical sciences are ‘author-date’ systems (e.g., Harvard system) and numerical systems (e.g., Vancouver system). Here, we discuss how to make an accurate, complete, and ethical citation, and provide simple and practical guides to organize references in a scientific medical paper.

An abstract is a self-contained, short, powerful statement that describes a larger body of work. It may be incorporated as part of a published paper, book, grant proposal, thesis, research report, or a conference paper. An abstract of a scientific paper will be published online independently, so it should make sense when it is read alone. An abstract of a hypothesis-testing paper consists of at least four key elements, as follows: (1) study question/hypothesis/aim, (2) experiments/material and methods, (3) results, and (4) response to the question/conclusion(s). The abstract usually begins with a background and may end in applications, recommendations, implications, or speculations. The abstract is one of the many features of a manuscript that competes for the readers’ attention; therefore, it should be informative, accurate, attractive, and concise. Since a huge amount of work must be compressed into a few sentences, writing an abstract may be a difficult task that needs professional skills. Here, we provide a practical guide to writing an abstract and selecting keywords for a hypothesis-testing medical paper.

The title of a paper is “like a hat on a head or the front door to a house” and its initial impression. Writing a good and effective title makes the paper more retrievable by search engines and maximizes its impact in the scientific community. The paper’s title presents what has been studied, how it has been done, and what are the major results. A well-written title is balanced for being informative and concise, as well as attractively conveying the main topic, highlighting the importance of the study. For writing a good title, it should be drafted correctly, accurately, carefully, and meticulously by the main study keywords. By removing extra and unspecific words, the final title should be unambiguous, memorable, captivating, and informative. Here, we provided an overview of the importance and function of the title as well as different types of titles in scientific medical writing. We also focused on the content and organization of the title of a hypothesis-testing paper. In addition, the features of a good title were discussed.

Graphs, an effective form of data presentation, are used for summarizing complex information and making them easier to understand. Extracting numerical data from graphs, which is commonly required in systematic reviews and meta-analyses, is however a challenging issue. Since this kind of results presentation is common, ignorance of such data may result in publication bias when conducting meta-analyses. On the other hand, contacting the authors of a particular publication in order to retrieve the data may take a long time and is often not very fruitful. In this case, there are a few software and methods that may be used for data extraction; however, using these software is costly and not simple as well as different types of graphs need different extraction methods. Here, we have described a simple reproducible method for extracting data from graphs using Adobe Photoshop.

Thyroid hormones are involved in the regulation of hydrogen sulfide (H2S) biosynthesis. The aim of this study is to determine effects of thyrotoxicosis on H2S levels and mRNA expression of cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) in the adipose tissue of rat.

Male rats were divided into the control (n=8) and thyrotoxicosis groups (n=8). Thyrotoxicosis was induced by adding L-thyroxine (12 mg/L) in drinking water for 21 days. Serum levels of free triiodothyronine (FT3), free thyroxine (FT4), total T3 (TT3), and total thyroxine (TT4) as well as thyroid stimulating hormone (TSH) were measured on day 21. H2S concentrations in serum and epididymal adipose tissue, as well as mRNA expressions of CBS, CSE, and 3-MST in epididymal adipose tissue were measured on day 21.

Serum levels of FT3, FT4, TT3 and TT4 were significantly higher, whereas TSH level was significantly lower in rats with thyrotoxicosis. Compared to controls, H2S levels (µmol/L) were lower in serum (43%, P<0.001) and epididymal adipose tissue (30% P=0.044) of rats with thyrotoxicosis. Thyrotoxicosis decreased mRNA expression of CSE (62%, P<0.001) and increased mRNA expression of CBS (116%, P=0.013) but not 3-MST in the epididymal adipose tissue.

Thyrotoxicosis decreased H2S levels in the serum and epididymal adipose tissue, an effect which can be due to decreased mRNA expression of CSE. Decreased serum and adipose tissue levels of H2S may contribute to the pathophysiology of thyrotoxicosis.

Advancements made in medicine during centuries have been disclosed importance of using animal for research in biology. Appropriate conduction of animal researches needs skilled and experienced researchers who are aware of principles for using laboratory animals. Regarding scientific activities, ethical considerations for using of animals in experiments that are associated with pain and even death have been challenging issue overtime. Therefore, considering animal rights is one of the concerns of researchers; in addition to maintaining animal health, stick to animal rights is also resulted in more accurate and precise results. Rats are mostly used for scientific experimentations because of having short reproductive duration as well as their easy and inexpensive breeding. Currently, use of available standards for laboratory animal care and use is one of the conditions for accepting articles in scientific journals and international seminars. The aim of this study is to provide an overview on ethical considerations for using rats in biomedicine researches.

Rats are used in a great number of researches in biology, in order to be committed to ethical principles and animal rights during experimentations and also having more precise results, it is necessary to adhere to standards for establishing animal facilities, to train staffs and researchers, and finally to design and support centers for audit.

The discussion section of a scientific paper is supposed to interpret and elucidate the significance of the study findings, highlight current knowledge available on the research problem being investigated, and explain the novel aspects emerging from the findings of the study in moving the field forward. A well-written discussion should provide clear “statements of the main findings”, “possible explanations and implications”, “strengths and weaknesses of the study and other studies”, “unanswered questions”, and “suggestions for future research”. The authors also need to clarify the external validity of the findings and show how the findings can be generalized. In this review, we focus on the function, content, and organization of the “discussion section” of a hypothesis-testing paper. Beyond providing the most important principles and common strategies for organizing the discussion section, we also discuss metadiscourse, scientific explanation (reasoning and contextualization), and models of scientific explanation.