Monoclonal antibodies recently developed against the 42,000-dalton protein of two rotavirus strains were used in an enzyme-linked immunosorbent assay to determine the subgroup specificity of 252 specimens collected during a 45-month period from Venezuelan children with rotavirus gastroenteritis. Subgroup 2 rotavirus was shed by 85% of the children, whereas only 14% shed subgroup 1 rotavirus (one-half of them in a 3-month period). No differences were found in the occurrence of fever and vomiting between children shedding either rotavirus subgroup, but it appeared that the syndrome tended to last longer in children shedding subgroup 2 rotavirus. The monoclonal subgrouping enzyme-linked immunosorbent assay seemed to be more sensitive than an immune adherence hemagglutination assay, an enzyme-linked immunosorbent assay with polyclonal antibodies, or the electrophoretic analysis of RNA extracted from the virus. Overall, 99% of the specimens could be subgrouped by this assay.

Antibodies, Monoclonal↗

PubMed1983

A dot hybridisation assay for detection of rotavirus.

A "dot" hybridisation technique for the detection of rotavirus in stools and other biological materials is described. The assay is based on the in-situ hybridisation of labelled single-stranded RNA probes, obtained by in-vitro transcription of rotavirus particles, to heat-denatured rotavirus RNA immobilised on nitrocellulose membranes. The method is highly specific and allows for the detection of as little as 8 pg of viral RNA. Its use for the detection of rotavirus in stool suspensions and rectal swabs obtained from children with diarrhoea may facilitate epidemiological studies of rotavirus gastroenteritis.

Child↗

PubMed1982

Genetic relatedness among human rotaviruses as determined by RNA hybridization.

Viral RNAs from human rotaviruses were compared by gel electrophoresis and by hybridization to probes prepared by in vitro transcription of two well-characterized laboratory strains (Wa and DS-1). Also, the viral RNAs were compared by hybridization to probes prepared from three of the test viruses. Thirteen specimens (diarrheal stools) were obtained from infants and children 5 to 21 months old on a single day at the emergency ward of the Caracas Children's Hospital, and an additional specimen was obtained from the same hospital 6 months before. When the electrophoresed viral RNAs were stained with ethidium bromide and examined by UV light, five different migration patterns (electropherotypes) were distinguished on the basis of differences in mobility of the RNA segments. The hybridization technique that was employed permitted only qualitative comparisons of corresponding genes of different human rotaviruses. Ten of the specimens contained enough virus to yield sufficient RNA for hybridization studies. Eight of the viruses studied by hybridization contained 4 to 11 genes that reacted specifically with the Wa probe to yield double-stranded RNA segments with a mobility similar to that of Wa viral RNA or test virus RNA. The other two viruses contained 11 genes that reacted specifically with the DS-1 hybridization probe to yield double-stranded RNA segments with a mobility similar to DS-1 viral RNA or test virus RNA. A more complex picture emerged when hybridization probes were prepared from three of the test viruses and used to compare the different electropherotypes. Corresponding genes that exhibited similar migration did not necessarily exhibit homology when studied by hybridization. Also, some corresponding genes that exhibited homology did not have the same mobility by gel electrophoresis.

Child, Preschool↗

PubMed1970

Gas-liquid chromatographic determinatin of chlorpheniramine in blood plasma.

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Chlorpheniramine↗

PubMedDate not supplied

Heterogenous expression of the EGF-receptor in human breast carcinoma.

The epidermal growth factor receptor was analyzed in the membrane fraction from a series of human breast carcinomas using a radioligand assay. The results were compared to immunostaining with monoclonal antibodies on tissue sections. All tumors with detectable receptor levels as measured by ligand binding showed a positive staining with monoclonal antibodies. In such tumors more than 50 percent of the cells were receptor positive with varying intensity. Tumors classified as receptor negative with the radioligand assay could be divided into two major groups based on their immunostaining. The largest group showed no reactivity with monoclonal antibodies. In a second smaller group, a positivity was observed in small clusters of tumor cells while the majority of cells were negative. The staining intensity in such clusters was usually low. It seems possible that this heterogenous expression of the epidermal growth factor receptor is of significance with respect to clonal selection in tumor spreading.

Antibodies, Monoclonal↗

PubMedDate not supplied

High expression of the EGFR in fibroadenomas compared to breast carcinomas.

The epidermal growth factor receptor and its ligands have been implicated as being involved in normal mammary development and breast cancer genesis. Northern blotting was used to assay the mRNA levels of the epidermal growth factor receptor and three of its ligands: the epidermal growth factor, the transforming growth factor alpha and the Amphiregulin in 16 primary carcinomas, 2 metastases and 5 fibroadenomas. In addition, the mRNA levels of the other members of the epidermal growth factor receptor family, erbB2 and erbB3 were also analysed. We found limited expression in the breast carcinomas while all the fibroadenomas showed expression at high levels. Therefore we suggest that the epidermal growth factor receptor plays an important role in the development of fibroadenomas. The erbB2 and erbB3 were more strongly expressed than the epidermal growth factor receptor in the primary carcinomas. This suggests that they could be of importance in breast carcinogenesis.

Base Sequence↗

PubMedDate not supplied

[Ultramicro ELISA to the detection of IgM antibodies in Mycobacterium leprae using dry blood samples].

In this work the adequate conditions for the detection of IgM antibodies to PGL-I in eluates from dried blood spots using the UMELISA HANSEN and the SUMA technology are established. A total of 300 blood donors and 58 leprosy patients samples were studied. For both populations, in the previously established conditions, we compared the results of the eluates from dried blood spots with the serum samples, and was obtained a correlation of 0.919 in blood donors, 0.969 in patients, and 0.954 for the total of both populations. It was also obtained a level of agreement of 98% in patients and 96% in blood donors. In the patients population was found a sensitivity of 93% and an specificity of 100% for the eluates of dried blood spots evaluated by the UMELISA HANSEN in the comparison with the serum samples analized by the same assay.

Antibodies, Bacterial↗