Assessment of the IgG index in dogs by indirect immunoenzimatic assays as diagnostic tool for inflammatory diseases of central nervous system.

The IgG index measures the intrathecal immunoglobulin production and it is a useful tool for diagnosis of inflammatory diseases involving the central nervous system. This index is based on the precise quantification of albumin and IgG in canine cerebrospinal fluid and serum. Here, we report the development of an indirect competitive ELISAs for the detection of both antigens. Thirty-two dogs were included in this study, divided into three experimental groups. Group A was composed of 22 healthy animals, as determined by standard clinical examination. In group B, six animals, presented neurological pathologies associated with endogenous IgG production and, in group C four animals presented neurological diseases or symptoms not associated with intrathecal IgG production. Cerebrospinal fluid and serum samples were obtained from these animals. As expected, by using the indirect ELISAs proposed here, the IgG indexes obtained in healthy animals (A) were 0.371+/-0.252 (SD). In B and C, the values (3.002+/-1.897; 0.36+/-0.306, respectively), were in agreement with the pathologic conditions of the individuals in each group. Thus, the immunometric competition ELISA methods proposed here allow the discrimination of abnormal intrathecal IgG production, in a variety of inflammatory pathologic conditions of the central nervous system.

Molecular analysis of cerebrospinal fluid in viral diseases of the central nervous system.

The use of nucleic acid (NA) amplification techniques has transformed the diagnosis of viral infections of the central nervous system (CNS). Because of their enhanced sensitivity, these methods enable detection of even low amounts of viral genomes in cerebrospinal fluid. Following more than 10 years of experience, the polymerase chain reaction or other NA-based amplification techniques are nowadays performed in most diagnostic laboratories and have become the test of choice for the diagnosis of several viral CNS infections, such as herpes encephalitis, enterovirus meningitis and other viral infections occurring in human immunodeficiency virus-infected persons. Furthermore, they have been useful to establish a viral etiology in neurological syndromes of dubious origin and to recognise unusual or poorly characterised CNS diseases. Quantitative methods have provided a valuable additional tool for clinical management of these diseases, whereas post-amplification techniques have enabled precise genome characterisation. Current efforts are aiming at further improvement of the diagnostic efficiency of molecular techniques, their speed and standardisation, and to reduce the costs. The most relevant NA amplification strategies and clinical applications of to date will be the object of this review.

Assessment of central nervous system involvement in gambiense trypanosomiasis: value of the cerebro-spinal white cell count.

OBJECTIVE: To assess, in a clinical setting, the comparative values of conventional criteria used in the diagnosis of central nervous system (CNS) involvement in Trypanosoma brucei gambiense sleeping sickness: white cell count (WCC) in cerebrospinal fluid (CSF) > 5 x 10(6) cells/l; total protein concentration in CSF > 40 mg/100 ml); evidence of trypanosomes in CSF following double centrifugation (DC). METHOD: In vitro culture of CSF was used as the gold standard. RESULTS: The study showed that WCC is, by itself, as sensitive for the diagnosis of the CNS involvement as the usually recommended combination of three conventional criteria. The specificity of WCC is improved while the sensitivity is reduced when the cut-off point is set at a higher value (WCC > 10 X 10(6)/l). CONCLUSION: In poorly equipped laboratories, the diagnosis of CNS involvement in patients with confirmed systemic infection should be based only on the WCC. However, a pilot study is needed to assess the feasibility and reliability of the WCC handled by 'front line' personnel, for different cut-off values.

Assessment of a possible imbalance between tumor necrosis factor (TNF) and soluble TNF receptor forms in tuberculous infection of the central nervous system.

Distributions of tumor necrosis factor (TNF) and its soluble receptor forms, R55-BP and R75-BP, were analyzed in the cerebrospinal fluid of patients with severe acute or chronic central nervous system infections. Tuberculous infections were associated with high ratios of R55-BP and R75-BP to TNF, 27.2 and 28.0, respectively, suggesting a small biologically active fraction of TNF. The opposite was found in subjects with acute bacterial meningitis. They had large fractions of biologically active TNF and thus low ratios of R55-BP and R75-BP to TNF, 3.7 and 4.0, respectively. It is hypothesized that chronic infectious diseases, such as tuberculous infections, may be associated with inadequate production of TNF and a concomitant relative increase of soluble TNF receptors, which may prolong the disease.

Cerebrospinal fluid cultures and analysis.

Prompt and accurate diagnosis of acute central nervous system infections is of vital importance to the emergency physician. With the advent of modern antimicrobial therapy, the nearly uniformly fatal outcome of untreated bacterial meningitis can be reduced substantially. Proper test selection is crucial in arriving at a correct and timely diagnosis. A variety of tests are currently available for evaluation of the patient with an acute central nervous system infection. We review the current state of the art in central nervous system testing. Cost considerations and an algorithm for efficient selection of appropriate tests are presented.

Assessment of damage to the central nervous system by determination of S-100 protein in the cerebrospinal fluid.

S-100 protein was determined by Particle Counting ImmunoAssay in the CSF of patients with various neurological disorders. With a limit of sensitivity of 2.5 micrograms/l this brain-specific protein was detected only in samples from patients with acute damage of the central nervous system, particularly in compression of the spinal cord by tumour, ischaemic disorders, subarachnoïd bleeding and haematoma, and viral or suspected viral infections. Our results support the assumption that S-100 is a reliable index of central nervous system damage and that changes in its concentration could have a prognostic value.