جستجوی مقالات مرتبط با کلیدواژه « بیماری زایی » در نشریات گروه « پزشکی »

Thyroid cancer is the most common endocrine malignancy. Molecular analysis of thyroid tumors has shown that the cause of its development, as with other cancers, is the accumulation of genetic and epigenetic changes along with progressive disorders. This study aimed to provide a comprehensive overview of the genetic alterations related to the pathogenesis of thyroid cancer. For this purpose, PubMed and Science Direct databases were searched from the beginning of 2018 to January 5, 2022, to investigate the relationship between genetic alterations and the pathogenesis of thyroid cancers. The keywords used included a combination of “Thyroid cancer/carcinoma/neoplasm” AND “pathogenesis” AND “genetic alterations”. The results showed that the most frequently reported genetic modifications included independent mutations, especially in the BRAF, RAS, TERT, and TP53 genes, gene rearrangements, especially in the RET, TRK, BRAF, and PAX8/PPARγ genes, numerical changes, and common co-mutations. The connection between these changes and numerous secondary molecular changes leads to the strengthening and synergy of their effects on the molecular pathogenesis of cancer. In addition, genes involved in DNA repair, signal transmission, and cell cycle control are affected more by genetic alterations, and mutations in the mitogen-activated protein kinase (MAPK) pathway and somatic mutations in the genes involved in the PI3K-AKT pathway lead to tumorigenesis and its progression in most cases. Therefore, secondary molecular disorders and simultaneous genetic alterations lead to synergism and genetic enhancement in thyroid tumorigenesis. A better understanding of the molecular pathogenesis and the discovery and recognition of markers can provide prognosis and realize potential clinical solutions for managing and treating thyroid cancer.

Thyroid cancer is the most common endocrine cancer. The study of the signaling pathways involved in thyroid cancer, such as PI3K/AKT/mTOR and their driver mutations, has significantly improved the understanding of the molecular pathogenesis of thyroid cancer. Consequently, targeted therapies have been developed using tyrosine kinase receptors and cascade proteins inhibitors. PubMed database and Science Direct website were searched to investigate the alterations in this signaling pathway in thyroid cancer from January 2016 to January 2023. Articles related to clinical symptoms, conventional treatments, histopathology, and diagnostic tests, as well as reports, letters to the editor, results of confer ences, and annual meetings, were excluded from the study. Then the remaining articles were carefully studied. Keywords included thyroid neoplasm, thyroid carcinoma, thyroid cancer, and PI3K. Somatic mutations and increased expression of the PIK3CA gene, the mutations in PTEN tumor suppressor gene, RAS, BRAF, and RET proto-oncogene mutations, CTNNB1 and EIF1AX gene mutations, RET/PTC, PAX8/PPARγ, and NTRK rearrangements, as well as AKT mutations and rearrangements, were the most important alterations that increased the expression of PI3K/AKT pathway proteins. This pathway and its connections with other signaling pathways were one of the leading reasons for the development and recurrence of thyroid cancer. Understanding the intracellular network of signaling pathways based on tyrosine kinase receptors, such as PI3K, and their cross-talk in physiological and pathological conditions, as well as their driver mutations, are the goal of research in recent years to develop combination therapies using inhibitors of these pathways.

Acinetobacter baumannii is a gram negative and it is one of the most important and drugresistance infections in hospitals.After Staphylococcus aureus and Pseudomonas aeruginosa, Acinetobacter baumannii is one of the included multidrug resistance infectious bacteria. The aim of this study is to review of pathogenesis and drug-resistance mechanisms in Acinetobacter baumannii.

Methods and Materials:

 International scientific databases including PubMed, Scopus and google scholar were used to review the articles. Out of the 150 articles obtained, only 105 of them with full text have been used in the study. Moreover, articles with abstracts and those received money were excluded from the study.

The rate of drug resistance is growing by examining the scientific papers in most countries of the world. This bacterium gained a specific mechanism of resistance which is a cause of global concern for this organism. Beta-lactamase enzyme producing genes such as OXA, TEM and others are widespread.

In less developed countries, with the indiscriminate use of antibiotics in the society and, in most cases, without the cultivation of pathogenic agents, it causes the emergence and acquisition of resistance genes by the organism. It is recommended that doctors in the hospital request microbial culture from infected samples before treating hospitalized patients in order to prevent resistance as much as possible.

Coronaviruses have four genera, including alpha, beta, gamma, and delta. The novel coronavirus, coronavirus disease 2019 (COVID-19), is a beta coronavirus type. This is not the first virus that involved the world and viruses have caused serious epidemics and pandemics throughout history. This review study investigated the structure of the COVID-19 virus, host receptors, function of the renin-angiotensin-aldosterone system in the human body, immune system response against the virus, and treatment methods.

The present narrative review study used the articles indexed in the international databases, namely Google Scholar, PubMed, ScienceDirect, and PLOS One, and domestic databases, including SID and Magiran, up to 2020. After reviewing the abstracts of 160 articles, similar and unrelated items were discarded. Finally, 52 papers were reviewed in this study.

The obtained results showed that the high tendency of the COVID-19 virus for binding to angiotensin-converting enzyme 2 (ACE2) increased the risk of disease and its transmission. In addition, decreased ACE2 reduced the risk of viral infection; nevertheless, its presence also protected lung cells from damage caused by the virus through the production of angiotensin I-VII.

The formation of bilayer vesicles by coronaviruses prevents the expression of ribonucleic acid (RNA)-recognizing receptors in the host. Because the human body fights viral RNA after its detection and the COVID-19 virus is a packet-type virus, the destruction of the virus pack may be a solution for its eradication. However, for the treatment of the disease caused by the COVID-19 virus, it is necessary to have a thorough perception of the structure and function of the virus in order to find an effective method.

The coronavirus disease 2019 (COVID-19) or severe acute respiratory syndrome coronavirus 2, has become the current health concern to the entire world. Initially appeared in Wuhan, China around December 2019, it spread to almost 216 countries due to its high contagious nature, so the World Health Organization recently declared the pandemic feature of the infection. SARS-CoV-2(COVID-19) which is genetically similar to SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV) is an enveloped, single and positive-stranded RNA virus with a genome comprising 29,891 nucleotides, which encode the 12 putative open reading frames responsible for the synthesis of viral structural and nonstructural proteins which are very similar to SARS-CoV and MERS-CoV proteins. Currently, there are no approved treatments for COVID-19.  For this reason, we reviewed existing publications about Coronavirus Disease 2019 (COVID-19) regarding epidemiology, pathophysiology, diagnosis and treatments.

Given the various investigations on the Virus (15928 publications in MEDLINE database, Until May 26, 2020) and various clinical data generated by the large number of laboratories, clinicians need accurate evidence regarding effective medical treatments for this infection. In this review, MEDLINE, SCIENCE DIRECT and Scopus databases were searched for relevant articles.

Since the emergence of COVID-19 infection there was a large interest in the development of an effective therapy for this disease. In this review, we summarized the available literature on possible therapeutic options including in vitro, animal and human studies. This review has presented a picture of the current findings on the epidemiology, clinical features, diagnosis, management, and prevention of COVID-19.

The COVID-19 epidemic represents the world's biggest public health crisis. Clinical trials that have begun to look for potential treatments for COVID-19 are very high, but unfortunately have not yet led to the development of an effective drug. Thus, to overcome on this crisis preventive and coordinated emergency measures between all countries are needed.

Coronaviruses are a large family of viruses that usually cause mild to moderate upper respiratory tract illnesses. The newly emerged sever acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was reported in late 2019 and causes coronavirus disease 2019 (COVID-19). Due to the novelty of the virus, new scientific evidence on various aspects of COVID-19 is reported in the literature continuously.Common symptoms of COVID-19 include fever, dry cough, fatigue, myalgia, arthralgia and Shortness of breath. Some articles have also reported on various manifestations of SARS-CoV-2 infection outside the respiratory tract. The affected organs are gastrointestinal tract, central nervous system, skin, olfactory system, cardiovascular system, liver, kidney and eye.The summary of extra pulmonary involvements by COVID-19 are anosmia, ageusia, erythematous rash, chickenpox-like blisters, acute cardiac injury with increased cardiac troponin levels, inflammation and edema of the renal parenchyma, gastrointestinal symptoms such as diarrhea and vomiting, abnormal liver function with increased levels of alanine and aspartateaminotransferase and neurologic symptoms ranging from headache to stroke. The hypothetical pathophysiologic mechanisms of systemic manifestations of COVID-19 are overproduction of cytokines (cytokine storm), hypoxemia, direct SARS-CoV-2 damage or combination of these mechanisms. Further studies are needed to demonstrate the relationship between outcome of COVID-19 and pathogenesis.

Corona viruses are old viruses which are divided into three groups. Groups one and three viruses induce disease in animals, and human viruses such as MERS and SARS are in group two.

This study was performed using international scientific sources and new researches findings.

Corona viruses are in the form of tiny spherical particles, and genome of the virus, which contain a single-stranded RNA, it causes changing in pathogenesis and severity of the virus and its sensitivity to antiviral antibodies. Attaching the virus to the cell is the first step in affecting a host. This is very important step and determines the tropism and the onset of viral infection. After virus binds to the cell by S protein, it fuses to the cell membrane and release the viral RNA genome inside the host cell cytoplasm. Human coronaviruses enter and grow in the epithelial cells of the upper respiratory system, and also alveoli and the lower respiratory system. But in COVID-19, it is not obvious the organs which virus penetrates and grows. The best diagnostic test is RT-PCR, but sometimes report false-negative results. It is very useful if this test used with clinical symptoms and radiological images. Serological methods have been used for some coronavirus and SARS viruses. One of the serological methods is testing serum level of IgG and it is useful in determining the asymptomatic infection or exposure to virus. The exact date of the virus's appearance is not known, but seems it existed some time before December 2019, or that it was not tested or reported.

Physiopathology of the virus, involved cells and tissues, established level of immunity and the pathogenesis mechanism and future random mutations of the virus are not fully understood. It is hoped many of these issues will become clear in the future.

Anaplasma phagocytophilum is a gram-negative intracellular bacterium that transmitted by hard ticks. A. phagocytophilum infect and multiply in the organs of ticks, in particular the salivary glands which enable the transmission to vertebrate hosts during feeding. The tick becomes infected by feeding on an infected host and there is transstadial but not transovarial passage of the organism. The majority of ticks are infected with the organism in enzootic areas. There are strains of A. phagocytophilum that have biological and ecological difference, including variations in host pathogenicity, vectors and geographical distribution. The organism has an interesting feature to grow in neutrophils by stopping the antibacterial activity of neutrophils. The bacterium is able to survive in the immune host, using complex mechanisms of antigenic variation. A. phagocytophilum infects humans and various animal species including dogs, sheep, cows, horses, wild deer and rodents. The disease is known as human granulocytic anaplasmosis in humans, canine granulocytic anaplasmosis in dogs, equine granulocytic anaplasmosis in horse and tick borne fever in ruminants. Cattle tick borne fever caused by A. phagocytophilum is characterized by high fever, reduced milk yield, inclusions in circulating neutrophils, leukopenia, abortions, reduced fertility, coughing, respiratory signs and swelling of the hind limbs. Clinical signs of human occur a week after the tick bites, the disease usually presents as an acute, sometimes fatal febrile syndrome, illness characterized by headache, chills, myalgias, arthralgia, malaise, and hematological abnormalities, such as neutropenia, lymphocytopenia, thrombocytopenia, leukopenia, and elevated hepatic aminotransferase levels and may lead to death. In this review article the history, bacteriology, epidemiology, pathogenesis, diagnosis, treatment and prevention of the disease caused by A. phagocytophilum is written based on the latest scientific findings. Several hard tick species are distributed in Iran and they are the most important ectoparasites of animals. A. phagocytophilum has been detected not only in Ixodes ricinus but also in cattle and sheep of Iran using molecular techniques. However, despite the zoonotic potential of the agent, there is no evidence in the identification of A. phagocytophilum in humans, and it seems necessary to research on the prevalence and epidemiology of the disease in the human population.

Undoubtedly, H. pylori is the major human gastric pathogen, which infects the mucosal epithelium in 50% of world population. However, H. pylori infection is relatively prevalent globally; the majority of infected individuals are asymptomatic. The recent epidemiological studies show that the various gastro intestinal complications can be the result of genetic variation in H. pylori strains. To date, different virulence factors had been suggested for H. pylori, but none of them can be a good biomarker for specific gastric disorders. In this review article, we aim to describe a comprehensive view on what we found in H. pylori virulence research in Iran. Hopefully, in parallel with new advances in sequencing systems, we will have better overview of virulence phenomenon of H. pylori in near future.

Leishmania is an obligate intracellular parasite that causes a wide range of disease. This parasite is transmitted via bite of infected sandflies.and has promastigote form in sandfly. Promastigote form has two phase: none virulence logarithmic and virulence stationary phase. According to the accumulation of acid phosphatase (ACP) in stationary phase and its role in the virulence of the parasite, in this study the properties, km and Vm of ACP enzyme were measured in two logarithmic and stationary phases. The present study is a cross sectional study. To culture promastigotes, L.major(MRHO/IR/75/ER) from previously infected Balb/c mice were transferred to medium. Growth curve was generated by daily counting of the parasites and based on this curve logarithmic and stationary phases were divided. Frozen promastigotes of each stage with sodium acetate and Triton-X-100 were homogenized and ACP was measured by calorimetric assay. Logarithmic and stationary parasites were collected in the fourth and seventh days respectively. The rate of ACP activity was determined: 0.9 ± 0.03 in logarithmic and 1.18 ± 0.01 µM/min/mgprotein in stationary phases. Also Vm of this enzyme was 75.76 ± 0.57 in logarithmic and 98/04 ± 0.96 in stationary phases and Km was determined 142.93 ± 4.08 µM and 106.39± 1.14 µM in logarithmic and stationary phase respectively (P<0.05). In stationary promastigotes the rate of ACP activity and Vm were 23% higher and Km was 28% lower than in logarithmic phase. Changes in the properties of ACP is probably one of the essential factors for parasites to attack the macrophages and these variations are very important parameters in virulence of promastigotes.

Enterotoxigenic Escherichia coli is the most common bacterial agent producing diarrhea in the world wide. This bacterium includes some virulence factors such as; colonization factors and heat-labile toxin and/ or heat-stable toxin. Enterotoxigenic Escherichia coli attached to the intestinal epithelial cell surface through CFs and causes diarrhea by toxin secretion. Molecular pathogenesis stu-dies demonstrate that there are many pro-phylactic approaches for this infection. The best possible way is designing and prod-ucing efficient vaccine that enabeling to induc protective immunity against the most of bacterial strains. Vaccine candidate molecule (s) that are used to design a vaccine، in addition to possess immuno-genicity and safety; they should be wid-espread among variety of strains and co-ntain conserved and common epitops. This article pays attention to review some infor-mation and results of conducted researches on enterotoxigenic Escherichia coli vaccine and importance of the bacteria and its pathogenesis.

IntroductionPhospholipases are the major component of all eukaryotic bilayer cell membranes. and serve as a scaffold for membranes proteins. Phospholipases are a class of ubiquitous enzymes that have estrase activity and due to their ability to lyses of cell membrane can play an important role for pathogenicity of microrganisims. During this study using degenerate primers based on homologous amino acid sequences of some fungi phospholipase B (PLB), detection of Aspergillus fumigatus PLB3 was carried out.Materials and Methods After DNA extraction of A. fumigatus, A. niger, Fusarium venonatum and Aurobasidiumpullulans PCR reaction was carried out using degenerate primers. Predicted 2100 bp product from A. fumigatus was cloned in pGEMT-Easy vector and then transformed into E. coli Top 10 F’ competent cell for extraction of cloned DNA fragment. ResultSequence analysis of 2100 bp fragments using BLASTX software were revealed a high homology to published PLB sequences from other fungi.ConclusionPhylogenic tree analysis of PLB3 gene shows that PLB and potential PLB analogues like lysophospholipase are contained in a large cluster of the PLB family. A. fumigatus PLB gene is more closely related to A. oryzae, A. niger, Penicillium chrysogenum and Neurospora crassa than other fungi. Also, sequence availability of full length PLB3 gene represents a noteworthy breakthrough in the study of this opportunistic pathogen and function of PLB3 gene in pathogenesis of A. fumigates. Detection of PLB3 gene can be lead to preparing vaccine, blocker and laboratory marker for recognition of PLB3 gene products either in patient body or clinical samples.

The superficial layer is a part of the cellular envelop that is seen in bacteria and archaea. This superficial layer is a single layer structure composed of subordinate proteins or glycoproteins. The superficial layer is the outer most cellular structure that is in the exchange and reaction around environment with bacteria. This structure has very diversity in bacteria different types. The related articles to superficial layer were extracted of these articles: Pubmed, Elsevier Science, and Yahoo, from 1995 to 2010 years. For this purpose keywords were searched including superficial layer, pathogenesis, pathogen bacteria, There is consensus in the case of the superficial layer and about the existence of this superficial structure lead to increased pathogenesis in bacteria, in all of the research articles. S-layers in pathogen bacteria with bacteria protection against bacteriophages and phagocytosis, resistance against low pH, adhesion, stabilisation of the membrane and providing adhesion sites for exoproteins caused pathogenesis, infection resistant and antibiotic resistant in host.The result of this study shows the prevalence of considerable S-layer in pathogen bacteria and this matter identified the bacteria generator importance of this structure in the laboratory

Secretory extracellular Phospholipases are generally involved in hydrolysis of extracellular phospholipids and thus providing nutritive source of carbon, nitrogen, and phosphate. However, intracellular phospholipases perform metabolic functions and adjust biologic activities. Synthesis of phospholipases in different pathogenic microorganisms and their mode of action in virulence of the microorganism have been the center of attention in recent studies. During this study using degenerate primers based on homologous amino acid sequences of phospholipase D (PLD) search for detection of Aspergillus fumigatus was carried out. DNA extraction of A. fumigatus was performed and then using degenerate primers based on nucleotide sequences of Phospholipase D gene was degenerated. Predicted 850 bp product from A. fumigatus was cloned in pGEMT-Easy vector and then transformed into E. coli Top 10 F’ competent cell for extraction of cloned DNA fragment. Sequence analysis of 850 bp fragments revealed a sequence for the PLD gene of A. fumigatus with a high homology to published PLD sequences in other microorganisms. Gene sequence studies are generally conducted to determine the participation of gene expression in pathogenecity of microorganisms, the evaluation of biochemical features and physiologic function of gene product for understanding the basic knowledge to provide immunity, production of vaccine, drug, or blocker for gene product, utilizing the gene product, utilizing the gene product for infection detection and so on. Thus, cloning of a part of phospholipase D gene in order to full identification of nucleotides sequence of this gene could contribute to achieve those goals.