Evaluation of a rapid immunochromatographic test for diagnosis of dengue virus infection

A rapid (<7-min) immunochromatographic test for immunoglobulin M (IgM) and IgG antibodies to dengue viruses was evaluated by using hospital admission and discharge sera from 124 patients. The reference laboratory diagnosis was based on the results of virus isolation, hemagglutination-inhibition assay (HAI), and enzyme immunoassay (EIA). By the standard assays, patients experienced primary dengue virus infection (n = 30), secondary dengue virus infection (n = 48), Japanese encephalitis (JE) virus infection (n = 20), or no flavivirus infection (n = 26). The rapid test demonstrated 100% sensitivity in the diagnosis of dengue virus infection and was able to distinguish between primary and secondary dengue virus infections through the separate determinations of IgM and IgG. For all patients with primary dengue virus infection a positive test for IgM to dengue virus and a negative test for IgG to dengue virus were obtained, whereas for 46 of 48 patients (96%) with secondary dengue virus infection, a positive test for IgG to dengue virus with or without a positive test for IgM to dengue virus was obtained. The remaining two patients with secondary dengue virus infection had positive IgM test results and negative IgG test results. Furthermore, the rapid test was positive for patients confirmed to be infected with different dengue virus serotypes (12 infected with dengue virus serotype 1, 4 infected with dengue virus serotype 2, 3 infected with dengue virus serotype 3, and 2 infected with dengue virus serotype 4). The specificity of the test for nonflavivirus infections was 88% (3 of 26 positive), while for JE virus infections the specificity of the test was only 50% (10 of 20). However, most patients with secondary dengue virus infection were positive for both IgM and IgG antibodies to dengue virus, while no patients with JE virus infection had this profile, so cross-reactivity was only a concern for a small proportion of patients with secondary dengue infections. The rapid test demonstrated a good correlation with the reference EIA and HAI and should be useful for the rapid diagnosis of dengue virus infections.     

Comparative study of the pharmacodynamic and pharmacologic effects of Betaseron and AVONEX

The aim of this 1 week study was to compare the biologic effects induced by Betaseron and AVONEX using their approved dose, route, and schedule. Sixteen healthy volunteers were randomly assigned to receive either a single i.m. dose of AVONEX (6 million International Units [MIU]) or, every other day s.c. doses of Betaseron (8 MIU). Common side effects associated with interferon-beta (IFN-beta) treatment and biologic response parameters (neopterin, beta2-microglobulin, interleukin-10 [IL-10], and MxA protein levels in blood) were measured. Ibuprofen was administered to all subjects throughout the study. Fever, chills, and myalgia occurred most frequently and with the greatest severity between 6 and 12 h after the first dose of either IFN-beta. Despite the additional dosing of subjects in the Betaseron group, the incidence, duration, and severity of the side effects were not significantly different from those in the AVONEX group. Biologic response parameters reached similar maximum concentrations in both treatment groups. In the Betaseron group, neopterin and beta2-microglobulin levels remained significantly greater than baseline throughout the 7 day study, whereas those in the AVONEX group were elevated only through day 5. Betaseron treatment significantly increased IL-10 levels above baseline, but AVONEX treatment did not. The overall induction of neopterin, beta2-microglobulin, and IL-10 (as measured by area under the concentration-time curve) was significantly greater in the Betaseron group than the AVONEX group (p = 0.031). The results of this study demonstrate that the approved Betaseron dosing regimen, in combination with ibuprofen use, provided a significantly greater and more consistently elevated biologic response compared with that of AVONEX and did so with a side effects profile comparable to that of once a week AVONEX dosing.     

Characterization of axenic isolates of Giardia intestinalis established from humans and animals in Germany

A total of 15 isolates of Giardia intestinalis, the first axenic cultures of this organism to be described from Germany, were established in Bonn from faecal cysts obtained from human and animal stool specimens. Measurement of in vitro growth kinetics for 12 of the isolates revealed 3 phenotypes ('rapid', 'medium-rate' and 'slow' growers) characterized by generation times of 9-11 h (5 isolates), 12-15 h (5 isolates) and > or = 18-20 h (2 isolates), respectively. Cloned sublines exhibited growth rates similar to those of the parent isolates. Genetic analyses involving use of the polymerase chain reaction to amplify segments of genes encoding variant-specific surface proteins or the enzyme glutamate dehydrogenase, coupled with the detection of restriction-fragment-length polymorphisms, identified genotypes belonging to three previously described genetic groups. Seven isolates (from humans, a calf and a chinchilla) were typed to genetic group I--a potentially zoonotic genotype belonging to assemblage A, one of two major genetic lineages defined by analysis of G. intestinalis from humans and animals. Six isolates (all from humans) showed identity with the group II genotype--recovered thus far only from humans and also belonging to assemblage A. Two isolates (one from a human, the other from a monkey housed at the Cologne zoo) were classified as assemblage B genotypes. The in vitro growth rates correlated strongly with genotype, group I or group II (assemblage A) genotypes accounting for all of the 'rapid' and 'medium-rate' cultures and both assemblage B isolates being 'slow growers'. The data indicate that genetically based metabolic differences may determine how rapidly G. intestinalis isolates can grow in axenic culture.     

Castleman's disease--difficult diagnosis

A case of Mb. Castleman of the localized plasma cell type is reported. This disease expresses several symptoms from different organ systems and therefore an extensive investigation program is often performed. Diagnosis is possible through consideration of all clinical components at the same time: Refractory anaemia, high and refractory SR, weight loss, B-symptoms, but at the same time a relatively good health. CT-scan-demonstration of a localized tumour is an important clue. Histopathologically, the tumour shows vascular hyperproliferation and plasmacytosis of varying maturation. Immunophenotyping of the plasma cells and immunoblasts usually reveals a polyclonal population. Needle biopsies from several regions may be necessary to detect the polyclonality, because monoclonality is often widespread locally in the tumour. HHV8 is correlated to the multicentric PC-type of Mb. Castleman. However, no HHV8 was found in this case.     

Status spongiosus of rat central nervous system induced by actinomycin D

The effect on central myelin of Actinomycin D, an RNA--and, secondarily, a protein-synthesis inhibitor, has been studied by light and electron microscopy. The intracranial injection of this drug produced an extensive status spongiosus of the white matter in the cerebrum, cerebellum, brain stem and optic nerve within 48 h. The status spongiosus was due to vacuole formation within the myelin sheath and to enlargement of the extracellular space. Three types of vacuoles were observed: (a) the most common varieties formed between the inner tongue and the remainder of the myelin sheath; (b) a second variety formed by enlargement of the periaxonal space with separation of the axon from its myelin sheath, and (c) a less common type of vacuolization was due to splitting of the myelin lamellae at the interperiod line to form large intramyelinic vacuoles. Myelinic vacuoles were preceded by nuclear and cytoplasmic changes in oligodendrocytes, which included nucleolar segregation, disaggregation, and diminution in number of ribosomes. These changes were similar to those previously reported in a variety of cells exposed to Actinomycin D. It is suggested that myelin vacuoles result secondarily from the Actinomycin D inhibitory effect on oligodendroglial RNA--and protein-synthesis, rather than from a direct effect of this drug on the myelin sheath.