PubMed Health⌕ Search

Biomedical subjects

J Raga

Publications and source records attributed to J Raga.

6 recordsLinked to original sources
PubMed1998

[Virus-specific serum and fecal antibodies response in children with acute rotavirus gastroenteritis].

BACKGROUND: The analysis of the immune response to rotavirus infection and the characterization of the viral antigens recognized by specific antibodies are of great concern in evaluating the protection against rotavirus. MATERIAL AND METHODS: The levels of rotavirus-specific fecal (sIgA) and serum antibodies (IgM, IgG and IgA) were evaluated by ELISA in 25 children with acute gastroenteritis for rotavirus, in 11 of them during the acute and convalescent phases. The specificity of serum antibodies to viral polypeptides was characterized by immunoblotting. RESULTS: Serum IgM antibodies with a geometric mean titer (GMT) of 1/3,973 were the predominant antibodies detected during the acute phase. In comparison, IgG and IgA serum antibodies and sIgA coproantibodies levels were higher in the convalescent phase (GMT = 1/5,799, 1/257 and 1/137 respectively). Significant differences were observed for all the isotypes of immunoglobulins evaluated during the infection and in the convalescence (p < 0.01). Rotavirus-specific serum antibodies recognized mainly the structural VP6, VP7 and VP3/VP4 proteins. Other polypeptides also detected were VP1, VP5 and the non-structural NS34 protein. CONCLUSIONS: Rotavirus infection produce an intense humoral immune response both in serum and in the gut. Specific antibodies react against structural proteins of the internal (VP6) and external (VP7) capsids of rotavirus.

Antibodies, Viral↗
PubMed1984

Juvenile chronic arthritis in black and Indian South African children.

Although juvenile chronic arthritis (JCA) has been studied extensively in Whites in Western countries, very few data exist on JCA in children in developing countries and particularly in Africa. Accordingly, a retrospective study of 60 Black and Indian children with JCA was undertaken. The main findings were predominance of JCA of polyarticular onset with a relatively low occurrence of JCA of pauci-articular onset, a high prevalence of positive rheumatoid factor tests and a very low number of patients positive for antinuclear factor, and an equal overall sex ratio (however, there was a preponderance of males in the subgroup with JCA involving only 2 - 4 joints). Moreover, the vast majority of patients initially had a low haemoglobin concentration, a normal white cell count, an elevated erythrocyte sedimentation rate and a positive antistreptolysin O titre. The main differences between Black and Indian South African children with JCA and White children with the disease in Europe and North American appear to be the high prevalences of polyarticular onset and seropositivity, the equal sex ratio and the absence of a specific subgroup with pauci-articular onset and a positive antinuclear factor test.

Adolescent↗
PubMed1984

Usefulness of clinical features and liver biopsy in diagnosis of disseminated herpes simplex infection.

With the advent of effective antiviral treatment for disseminated herpes infection it has become important to be able to make a firm clinical diagnosis of this condition. We undertook a retrospective analysis of 20 patients with disseminated herpes simplex infection diagnosed at necropsy to derive useful clinical pointers to this severe form of the disease. The most useful clinical criteria were malnutrition, post measles state, and local herpes infection in addition to encephalopathy, enlarging hepatomegaly, and deteriorating pneumonia. The liver showed characteristic histological changes in 18 of 19 patients. These clinical criteria combined with liver biopsy were applied in a prospective pilot study of five patients at risk for disseminated herpes infection and the results were encouraging.

Biopsy↗
PubMedDate not supplied

Evaluation of reverse transcription and polymerase chain reaction (RT/PCR) for the detection of rotaviruses: applications of the assay.

Our aim was to evaluate the reverse transcription and polymerase chain reaction (RT/PCR) technique for the detection of rotavirus shedding by infected children as a routine diagnostic procedure, in comparison to the enzyme-linked immunosorbent assay (ELISA), electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) of rotavirus double-stranded RNA. Two-hundred and twenty stool specimens were collected from infants and young children with diarrhoea, and 10-20% faecal suspensions were made. Several methods of rotavirus dsRNA extraction were assayed. Electrophoretic analysis of viral RNA was carried out on 10% polyacrylamide gels followed by silver staining. RT/PCR was performed using oligonucleotide primers specific for both 3' and 5' ends of the rotavirus gene encoding VP7 which are highly conserved among group A rotaviruses. Following RNA extraction with phenol-chloroform and ethanol precipitation, RT/PCR could detect rotaviral RNA in only 11 of 25 samples known to contain rotaviruses by conventional methods. The purification of RNA extracts by CF11 cellulose and the application of the RNAID method were equally effective in extracting RNA and/or removing inhibitory substances from the faecal samples. RT/PCR led to the detection of 66 positive samples from 220 specimens tested (30%), whilst 64 specimens were positive by ELISA (29%), 59 (26.8%) by PAGE and 56 (25.4%) by EM. In our study, RT/PCR was 100 times more sensitive than the ELISA test in detecting rotaviruses serially diluted in a faecal suspension. Although RT/PCR is theoretically much more sensitive than ELISA, PAGE and EM for detection of rotaviruses, great care must be taken to remove inhibitory substances from the enzymatic reactions. We do not consider that RT/PCR should replace immunoassays with high sensitivity and specificity for rotavirus testing in faecal samples, although this technique has other applications, like the search for rotavirus in different clinical specimens (sera, cerebrospinal fluid, respiratory secretions, etc.) and in environmental samples, as well as the typing of viral strains using serotype-specific primers.

Child↗