Clinica chimica acta; international journal of clinical chemistry
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Review
Systematic reviews in laboratory medicine: principles, processes and practical considerations.
Systematic reviews and meta-analyses are generally accepted to represent the highest level of evidence, and are a cornerstone in practising evidence-based medicine. So far, these efforts have been largely confined to the evaluation of the efficacy and effectiveness of therapeutic and preventive interventions. Systematic reviews in laboratory medicine are scarce and many of them do not meet essential quality criteria [Clin. Chem. Lab. Med. 38 (2000) 577]. Most of these problems are related to the poor design and heterogeneity of primary research, and that there are no agreed methods or quality standards for making systematic reviews in laboratory medicine. ⋯ Systematic reviews of diagnostic interventions support clinical and policy decisions, the development of practice guidelines, clinical audit, technology assessment, economic evaluations, education and training, and identify gaps in our knowledge for future research. Systematic reviewing of laboratory data is expected to result in better, bigger and more reliable primary studies, which hopefully will support the diffusion of new diagnostic technologies with scientifically proven efficacy and effectiveness in the future.
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Neurological diseases are often associated with cerebrovascular dysfunction and changes in blood-brain barrier (BBB) function. This is important for two seemingly conflicting reasons. On the one hand, a leaky BBB may lead to brain disease by allowing extravasation of cells and molecules normally segregated in the periphery, while on the other hand an intact BBB may hamper drug delivery to the ailing brain. ⋯ Other markers of brain-to-blood barriers have been recently discovered by a proteomic approach. These proteins are virtually absent in normal blood, appear in serum from patients with cerebral lesions, and can be easily detected. We will present clinical and laboratory evidence supporting the use of these markers as modern neurodiagnostic tools.
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Vegetarians are at risk to develop deficiencies of some essential nutrients, especially vitamin B-12 (cobalamin). Cobalamin occurs in substantial amounts only in foods derived from animals and is essential for one-carbon metabolism and cell division. Low nutritional intake of vitamin B-12 may lead to negative balance and, finally, to functional deficiency when tissue stores of vitamin B-12 are depleted. ⋯ Stage III is characterized by increased levels of HCY and MMA in addition to lowered holotranscobalamin II. In stage IV, clinical signs become recognizable like macroovalocytosis, elevated MCV of erythrocytes or lowered haemoglobin. In our investigations, we have found stage III of vitamin B-12 deficiency in over 60% of vegetarians, thus underlining the importance of cobalamin monitoring in this dietary group.
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Induction of the protein procalcitonin during infection and inflammation was first described approximately 10 years ago. A large number of publications, primarily clinical studies, demonstrate the increasing use of procalcitonin in modern clinical practice. However, data on the biological function and origin of procalcitonin is scarce. ⋯ Procalcitonin obviously has certain biological functions, and it is also known to be specifically induced. Given the hormonal origin of the mature protein and the inflammation-related functions of its propeptides, some investigators suggest that procalcitonin should be referred to as a "hormokine," although its biological functions should be studied in more detail. This review will survey the data now available in recent publications on the induction, production sources, possible biological functions and clinical uses of procalcitonin.
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There are several issues driving the rapid advancement in diagnostic technology for acute cardiac syndromes. First is safety, primarily the need to improve sensitivity in lower-risk patients presenting with symptoms suggestive of ischemia; second is fiscal, especially to reduce the cost for the evaluation of low-risk chest pain patients; and third is therapeutic, including the ability to effectively risk-stratify patients who may be candidates for more aggressive therapy.