Actinomycetes

Actinomycetes are a group of metabolically dynamic microorganisms. They are better known for the production of a wide range of antibiotics, anticancer drugs, and industrial enzymes. Only a small number of species belonging to the order Actinomycetales are pathogenic. From the evolutionary perspective, actinomycetes form a bridge between the classic bacteria and fungi. The properties that mandate their classification with bacteria include prokaryotic cell structure and in vitro sensitivity to most antibacterial antibiotics. On the other hand, their tendency to form true branching with septate mycelium, external spores, and granulomatous tissue reaction in infected hosts bring them closer to fungi. The term “actinomycete” literally means “ray fungus.” Because of their fungus-like properties, actinomycetes have been traditionally studied by mycologists. By early 1970s, it became obvious that these are prokaryotic microorganisms, and most mycologists started avoiding them, but bacteriologists did not quite embrace them either. As a result the study of actinomycetes has fallen into a “no man’s land.”

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Introduction to Pathogenic Fungi and Superficial Mycoses

Fungi (singular fungus) are eukaryotes. They generally occur in two forms: yeast, which can be round or oval and basically unicellular, but capable of forming long chains called pseudomycelium; and the mold or filamentous. Some pathogenic fungi can be yeast-like inside animal tissue and filamentous in their natural habitat. Also, fungi have a highly developed form of sexual reproduction, but most can also multiply asexually. The natural habitat of a majority of fungi is soil where they perform their primary function in nature, that is, decomposing plant material and recycling the biomass in the ecosystem. However, certain pathogenic fungi are more frequently associated with pigeon or bat excreta. A majority of fungi are harmless to humans and animals. Only a small number of species are known to cause diseases in humans and animals though a majority of plant diseases are caused by fungi. The tissue reaction is usually granulomatous. Fungal infections do not respond to antibacterial antibiotics.

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Multiple Myeloma and Related Conditions

This heterogeneous group of conditions is associated with monoclonal immunoglobulin in serum or urine, and is characterized by disordered proliferation of monoclonal lymphocytes or plasma cells. The clinical phenotypes of these conditions are determined by the rate of accumulation, site and biological properties of both the ab- normal cells and the monoclonal protein.

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The Myelodysplastic Syndromes

Introduction

• The myelodysplastic syndromes (MDS) are a group of clonal haemopoietic disorders. They are characterized by:

• Ineffective haemopoiesis resulting in peripheral blood cytope- nias of all three lineages, but especially anaemia

• Increased risk (30%) of transformation to acute myeloid leukaemia

• MDS is mainly a disease of the elderly, with a median age at diag- nosis of 60–75 years. It does, however, affect younger adults also. MDS is rare in children, and is associated with genetic disorders such as Fanconi’s anaemia.

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Quality assurance in the laboratory

Quality assurance in the laboratory includes all aspects of the analytical work, from correct identification and preparation of the patient to ensuring that the laboratory result goes back to the doctor.

The prime objective of quality assurance is to ensure that the laboratory provides results that are correct and relevant to the clinical situation of the patient.

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Safety in the laboratory

● Each laboratory should have a written manual of safe laboratory practices which should be followed at all times.

● The laboratory should have a first-aid box (see section 3.8.2) and at least one staff member trained in first aid.

● The laboratory should be a work area only; visitors should be restricted.

● No food or drink should be consumed in the laboratory.

● Wear protective clothing and remove it before leaving the laboratory.

● Always consider any laboratory specimen as potentially infectious and handle it carefully; wear protective gloves.

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Intravenous fluid therapy

Does this patient need IV fluids?

The easiest and best way to give fluids is orally. The use of oral glucose and salt solutions may be life-saving in infective diarrhoea. However, patients may be unable to take fluids orally. Often the reason for this is self-evident, e.g. because the patient is comatose, or has undergone major surgery, or is vomiting. Sometimes the decision is taken to give fluids intra-venously even if the patient is able to tolerate oral fluids. This can be because there is clinical evidence of fluid depletion, or biochemical evidence of electrolyte disturbance, that is felt to be severe enough to require rapid correction (more rapid than could easily be achieved orally)

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