فصلنامه آزمایشگاه و تشخیص
پیاپی 28 (تابستان 1394)

microRNAs or miRNA refer to short RNAs (19 to 23 nucleotides), which control the expression of different genes. These molecules act as the principle regulators for various biological processes including development, differentiation, proliferation and apoptosis. Therefore, deregulation of miRNAs play an important role in different diseases such as cancer. Therefore, many studies have been performed to investigate miRNA’s biology and function. Many effective efforts have also been performed to promote miRNA’s detection and evaluation procedures. In this article, the biology of miRNA’s in various physiological and pathological processes will be reviewed and a few detection methods for miRNA will be introduced.

This review describes different characteristic of cell free fetal DNA including the origin, size and percentage of cell free fetal DNA compared to cell free maternal DNA. The small percentage of cell free fetal DNA in maternal plasma is the most important challenge for the routine usage of fetal DNA in clinic. After the discovery of cell-free fetal DNA in maternal blood during pregnancy, researchers tried to develop more reliable extraction and detection methods and now there are a promising view employing cell free fetal DNA for the non-invasive prenatal diagnosis.

In this section, the small conidia producing fungi will be discussed. These includes Cladosporium spp, which may be important human pathogens or common laboratory contaminants and Cladophialophora spp. Which are the most common causes of chromoblastomycosis and cerebral phaeohyphomycosis. Then, we will discuss about the Chaetomium spp. uncommonly responsible for human mycoses, Nattrassia magniferae, a common agent of dermatomycoses and onychomycosis in patients living or immigrating from tropical areas, Phoma, which rarely isolated from humans, and Coniothyrium (which caused infections in immunocompromised individuals) which have complex reproductive structures. Dematiaceous agents of mycetoma are the last organisms which will be explained here, these includes: Madurella mycetomatis and M. grisea, also Leptosphaeria and Pyrenochaeta species.

Type II diabetes is an increasing epidemic disease. Routine treatments of lowering glucose level and insulin enhancers-based therapies are options whether not clear they can put a stop on progress of the disease. New potential therapeutic goals are recognized and new compounds are being produced that they can decrease the blood sugar with the lowest risk of hypoglycemia and obesity and they can also protect the β-cell mass and increase their function. Humanin (HN) is a mitochondrial-derived peptide with 24 amino acids. Since the level of HN decline with age, it causes cardiovascular and Alzheimer's disease and so on. The effectiveness of humanin in improving the function of insulin could be a new therapeutic method in diabetes type II. As humanin inhibits IGFBP-3 it plays a more effective role in function of insulin, so that it can be a target of manufacturing drugs. Thus the aim of this study is to review the in vivo function of humanin and its mechanism of action in improvement of type II diabetes therapeutic manner. We searched Pubmed, Scopus, Ovid, Proquest and Magiran with the terms such as: humanin peptide, diabetes mellitus, type II diabetes, and hyperglycemia. The search covered 1997 until 2014. Among 45 searched articles, 38 references were studied. The results of the study show that HN represses the apoptosis and prevents cells from oxidative stress. Increasing insulin secretion, glucose metabolism and finally lowering the blood sugar are also the other features of HN. It seems HN has beneficial in vivo and in vitro effects. The discovery of this peptide could be a new therapeutic method in order to improve the status of type II diabetic patients. But further studies according to sex, age, genetics and the drug dosage is needed to uncover the gaps about its safety and effectiveness.

Staphylococcus aureus as one of the most common causes of food poisoning known in many countries. These bacteria have a variety of toxins, that they enterotoxin more important, and foods contaminated with the toxin that causes food poisoning. Staphylococcal enterotoxins (SEs) is proteins of the extracellular single chain of low molecular weight (22-29 kDa); Biological activity of these enterotoxins are similar But the antigen together different. These toxins are 23 different types, that cause nausea, vomiting, diarrhea, muscle aches and abdominal and sometimes lead to death. The purpose of this study was to review the role and importance of the Staphylococcus aureus enterotoxins (SEs) in food poisoning, pathogenesis, laboratory methods for purification and detection of the SEs in foods. This study was a systematic review; the data was collected using by various databases such as PubMed, Scopus, Science Direct, Scientific Information Database SID and IRAN MEDEX. For this purpose, the 5 key words (Staphylococcal Enterotoxins, Staphylococcal food poisoning, Food borne diseases, structure of Staphylococcal Enterotoxins and Detection of Staphylococcal Enterotoxins) was used to collected information from the database. The timeframe for this study was conducted between 1967- 2014 in the database. Inclusion criteria in the selection of articles was the keywords in the articles listed above. Finally, 40 articles to collect data and information from the scientific base were reviewed. Discussion & Staphylococcus aureus grows in a wide range of temperature and pH, the bacteria may grow in a wide assortment of foods. Therefore, food that is contaminated with SE-producing strains, if investment conditions are cold, can actually be the source of SE-outbreaks. Thus the need for cooperation epidemiologists, microbiologists, health food and veterinary experts together to reduce food poisoning caused by staphylococcal enterotoxin eating bacterium caused a prerequisite for the realization of public health.

Urinary tract infection is one among the most common infectious disease which occurs during pregnancy. Several physiological and hormonal changes during pregnancy may increase the incidence of infection among pregnant women. It can be symptomatic or asymptomatic. Asymptomatic bacteriuria can lead to the development of cystitis or pyelonephritis. Gram negative bacteria like Escherichia coli, Klebsiella pneumoniae, roteus, Providencia species, Pseudomonas aeruginosa, Enterobacter and Serratia are the most common etiological agent in both symptomatic and asymptomatic Urinary tract infection. Quantitative culture technique considered as the gold standard for the diagnosis of Urinary tract infection. Untreated urinary tract infections can lead to significant maternal and perinatal morbidity and mortality. Hence the proper treatment is of at most importance based on the urine culture and sensitivity reports. It is also important to conform the safety of drugs used during of pregnancy. Resistance of microorganism towards the commonly prescribing antibiotics is the most challenging factor for the treatment. Proper hygiene and various precautions may also help in preventing its reoccurrence.