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Biomedical subjects

J Nasser

Publications and source records attributed to J Nasser.

5 recordsLinked to original sources
PubMed1992

Serum IgG and IgM levels in new and regular long-term plasmapheresis donors.

This Australian study monitored the effects of monthly plasmapheresis on donor serum IgG and IgM levels in 127 new and 124 established plasma donors who donated 1014 units over a five-month period. Of the 251 donors, 3% had reduced total serum protein (TSP) levels, 7% had low IgG levels and 12% had low IgM levels prior to donation on at least one occasion over the study period. Statistical analysis showed that the TSP, IgG and IgM levels of new donors who had donated plasma on less than 10 occasions were no more likely to fall below normal than those of old donors. However, new and old donors whose IgG or IgM levels fell below normal at any time during the study had significantly lower levels of the relevant parameter on entry to the study. Followed longitudinally, IgG and IgM levels in old and new donors tended to fall, although levels fluctuated throughout the study. Statistical analysis failed to show any correlation between TSP levels and IgG or IgM levels. These parameters did not correlate significantly with the number of previous plasmaphereses, donor weight, volume collected or history of infection. This study highlighted the need for regular, specific quantitation of IgG and IgM levels as well as TSP in regular plasmapheresis donors. The frequency of testing is yet to be determined, in view of the high materials and labour costs of such a programme.

Adolescent↗
PubMed1986

A highly sensitive immunoenzymometric assay involving "common-capture" particles and membrane filtration.

This highly sensitive immunoenzymometric method involves monoclonal antibodies, a common-capture microsphere, and a rapid, membrane-filtration separation step. The common-capture solid phase is monoclonal anti-fluorescein antibody convalently attached to 6.5 micron-diameter latex particles. In sandwich-type assays for large-molecule analytes, the capture antibody is conjugated with fluorescein isothiocyanate and the probe antibody is conjugated with beta-galactosidase (EC 3.2.1.23). In competitive assays for small analytes, the analyte-beta-galactosidase conjugate competes with the analyte in the clinical samples for the fluoresceinated capture antibody. After simultaneous incubation of the reagents for 2 h, the bound and unbound reagents are separated by filtration through the bottom of each well of a 96-well plate. Substrate (4-methylumbelliferyl-beta-D-galactopyranoside) is then added to the wells, and the rate of product formation is determined kinetically for 12 min. The rate is proportional to the concentration of analyte in the sandwich assays and inversely proportional in the competitive assays. The assay results for choriogonadotropin, thyrotropin, digoxin, and thyroxin show the assay to be sensitive, rapid, and applicable to any size analyte. With this system, several different sandwich and (or) competitive-type assays can be performed simultaneously on the same plate.

Antibodies, Monoclonal↗
PubMed1979

[Cerebrospinal fluid in cysticercosis of the brain].

Cerebrospinal fluid (CSF) changes in brain cysticercosis have long been known. Its characteristic features are a mild or moderate pleocytosis with eosinophils, a slight or moderate protein increase with an elevated gammaglobulin concentration, and a positive complement fixation test. Unfortunately all these abnormalities are not always present together and difficulties may be encountered in the diagnosis. This paper presents a study based on the experience acquired in the CSF Laboratory of the Neurological Department of Escola Paulista de Medicina (São Paulo, Brasil) after 35 years' work, and 120.000 CSF specimens examined. The material consists of 147 cases of brain cysticercosis confirmed by necropsy, surgery, subcutaneous or intraocular cysticercus, x ray of the skull, and of 509 clinical observation with suggestive CSF changes. It is the purpose of this paper to appreciate the importance of each of the CSF tests and to observe the CSF abnormalities during the course of this disease. The results of the study of the 79 cases varified by necropsy or surgery showed that the characteristic CSF changes that make the diagnosis of brain cysticercosis were observed in 54 percent of the cases. The eosinophils were present in 82 percent, protein changes in 78 percent, complement fixation test in 70 per cent, hypertension in 55 per cent, and decreased sugar content in 27 per cent of the cases. In two cases the CSF was normal. As the eosinophils and the protein abnormalities may be seen in several other diseases, the complement fixation test for cysticercus should be regarded as the most important CSF test in the diagnosis of brain cysticercosis. The successive CSF specimens withdrawn of 40 patients during the course of this disease have shown that the abnormalities went on for 4 to 18 years observation, suggesting that the parasites were alive. On the contrary, in 11 other cases it was varified the final CSF normalization after 5 to 14 years, suggesting that the parasites were dead. The CSF was normal in 31 out of 42 patients with opaque nodules visible in skull films (calcified cysticercus). In the remaining 11 cases, the characteristic CSF findings were observed in 3, but in 8 cases the only abnormalities were positive complement fixation test or eosinophils. In 14 out of 26 patients with subcutaneous or introacular cysticercus there were the usual CSF changes but in the other remaining cases the CSF was normal. The absence of treatment for brain cysticercosis is consistent with the persistence of CSF abnormalities in the specimens examined during the course of this disease. This calls for an integrated prophylactic to all Latin-American countries in order to exterminate this serious disease for the well-being of the next generation.

Brain Diseases↗