[Immunomodulatory actions of antibiotics]. / Imunomodulatorna delovanja antibiotika.

INTRODUCTION: Antimicrob drugs and immune system interaction has been studied since the pioneer works of Metchnikoff. After the introduction of antibiotics in clinical practice this area has attracted little attention of investigators, because of the lack of standards. This is the reason that the studying of the influence of antibiotics on immune system is still at its beginning. AIM: To point out the immunomodulatory action of some antibiotics on certain components of immune system. METHODS AND RESULTS: The literature findings show that antibiotics express immunomodulatory action on some components of immune system such as fagocytes (polymorphonucleary, macrophages, monocytes), cytokines, immunoglobulines, and on cellular immunity. The principles of antibiotics action on phagocyte are the inhibition of chemotaxis and oxidants production. Macrolides applied for a short time enhance the phagocytic functions while their long use leads to immunosupression. Some cephalosporines and rifampicin in therapeutic doses inhibit the oxydative metabolism, of macrophages. Tetracyclines, clindamycines, chloramphenicol and tobramycin inhibit the synthesis of superoxyd anione. The action of some antibiotics on cytokine and specific antibodies is also important. Cellular immunity can be affected as well. After administration of certain antibiotics it takes 1-2 weeks to reestablish normal cellular immunity, and for other even more. CONCLUSION: There is still no clear standing on real effects of antibiotics on the immune system. Clinicians should search for more information from this new-old field of investigation in order to give more adequate therapy to patients.

[Influenza: a current medical problem].

INTRODUCTION: Acute respiratory infections are the most common infections in the human population. Among them, virus infections, especially those caused by influenza viruses, have an important place. TYPE A INFLUENZA: Type A influeza virus caused three epidemics during the last century. A high percetage of deceased in pandemics of 1918, and 1919 were young, healthy persons, with many of the deaths due to an unusually severe, hemorrhagic pneumonia. At the end of 2003, and the beginning of 2004, an epidemic emerged in South East Asia of poultry influenza caused by animal (avian) virus. Later it spread to the human populaton, with a high death rate of 73% and with a possibility of interhuman transmission. This review article provides an overview of the clinical manifestations, laboratory findings and chest radiographs. Apart from the symptomatic and supportive therapy, there are antiviral drugs and corticosteriods. CONCLUSION: The use of vaccine containing subtypes of virus hemagglutinins and neuraminidase from an influenza virus currently infecting the population has a great importance.

[Diseases caused by viruses and toxins in biological warfare and bioterrorism].

INTRODUCTION: Viruses and toxins, as well as bacteria and rickettsia can potentially be used as biological weapons in conflicts or in bioterrorism. USE OF BIOLOGICAL WEAPONS: The infection can be acquired by inhalation of aerosols, ingestion of contaminated food or water, or direct contact with the skin or mucosa. Special attention must be given to the possible use of genetically modified agents. CONCLUSION: This paper describes the clinical features of diseases caused hbi viruses (smallpox, hemorrhagic Jever and encephalitis) and toxins (botulinum, staphylococcal enterotoxin B, ricinus toxin and mycotoxins) their diagnosis, treatment, as well as basic preventive measures.

[Diseases caused by bacteria and rickettsia in biological warfare and bioterrorism].

INTRODUCTION: Until recently, the use of biological weapons was considered more from an academic than practical point of view. The list of agents and/or toxins that can be used as biological weapons is long. Some of them are highly lethal, while others cause morbidity and disability. BIOLOGICAL WEAPONS: Bacteria, rickettsia, viruses, fungi, protozoa and toxins can all be used as biological weapons. The infection may be acquired by inhalation of aerosols, ingestion of contaminated water or food or direct contact with infectious agents. Early recognition, diagnosis and treatment of these patients is of utmost importance. Special attention must be given to the use of genetically modified microorganisms. Medical protection from biological weapons is very important as well as continuous education. CONCLUSION: This article describes the main clinical characteristics of anthrax, cholera, plague, Q fever, tularemia, brucellosis, and glanders, as biological weapons, their diagnostics, treatment and basic prevention measures.

[Treatment options for chronic hepatitis C virus infection].

INTRODUCTION: The incidence of chronic hepatitis C virus (HCV) infection is rather high. Its most frequent consequences are chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. TREATMENT OF CHRONIC HCV INFECTION: In treatment of chronic HCV infection, interferons have antiviral, anriproliferative, and immunoregulatory action. Within the cell, they induce protein synthesis, inhibiting viral replication. The most important among them are RNA dependent protein kinase, and eukaryotic initiation factor. However, viral proteins prevent their phosphorylation and activation. In order to overcome this problem, treatment is prolonged, higher doses of lFN are used, as well as induction therapy. The optimal period for viral response is 52 weeks, while induction therapy has shown controversial results.

[Effects of interferons on hepatitis C virus infection].

INTRODUCTION: The consequences of hepatitis C virus infections (chronic hepatitis, liver cirrhosis and hepatocellular carcinoma) are one of the major problems in clinical medicine. The persistence of infection in spite of high specific antibody titre suggests that the virus has the abillity to "escape" the immunological response. INTERFERON THERAPY: Interferons are important components of the early host response to infection. They have antiviral, antiproliferative, and immunomodulatory activities. Many viruses have developed the ability to "annul" or alleviate the action of interferon by preventing its synthesis or by interfering with signaling pathways in the cells. During acute infection some of the non-structural proteins of HCV block regulatory factors that are responsible for the synthesis of endogenous infection. Within a cell, interferon induces a number of genes to produce proteins that prevent virus replication. Among them, the most important are RNA-dependent protein kinase and the eukaryotic initiation factor. However, viral proteins, especially viral envelope proteins and nonstructural protein 5A, prevent their phosphorylation and activation which enhance virus replication. These are the facts that have to be considered when using IFN in chronic hepatitis C patients.