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M C Campos

Publications and source records attributed to M C Campos.

7 recordsLinked to original sources

Role of microtubules and microtubule organizing centers on meiotic chromosome elimination in Sciara ocellaris.

Spindle formation and chromosome elimination during male meiosis in Sciara ocellaris (Diptera, Sciaridae) has been studied by immunofluorescence techniques. During meiosis I a monopolar spindle is formed from a single polar complex (centrosome-like structure). This single centrosomal structure persists during meiosis II and is responsible for the non-disjunction of the maternal X chromatids. During meiosis I and II non-spindle microtubules are assembled in the cytoplasmic bud regions of the spermatocytes. The chromosomes undergoing elimination during both meiotic divisions are segregated to the bud region where they associate with bundles of microtubules. The presence and distribution of centrosomal antigens in S. ocellaris meiotic spindles and bud regions has been investigated using different antibodies. gamma-Tubulin and centrin are present in the bud as well as in the single polar complex of first meiotic spindle. The results suggest that spermatocyte bud regions contain microtubule-organizing centres (MTOCs) that nucleate cytoplasmic microtubules that are involved in capturing chromosomes in the bud regions. The distribution of actin and myosin in the spermatocytes during meiosis is also reported.

Actins

Paternity testing with the F10 multilocus DNA fingerprinting probe.

Empirical analysis of 200 paternity cases by multilocus DNA fingerprinting with the F10 probe showed that it was capable of distinguishing fathers from non-fathers in every case. The average exclusion probability was 0.99998. A very effective discrimination parameter was the proportion of non-maternal (test) bands which cannot be detected in the alleged father (unassignable bands) among all test bands. Values below 0.2 were seen in true fathers while in all cases of non-fathers the values were above 0.35. Minisatellite mutations occurred at a rate of 0.004 per band per child. The distribution of band-sharing among first degree relatives and unrelated individuals showed only a small overlap. Thus, band-sharing of the F10 fingerprints should provide a useful statistic for testing genetic relationships in deficiency cases.

Base Sequence

Methotrexate hepatotoxicity in psoriatic patients submitted to long-term therapy.

Eighty-four patients with severe psoriasis who required methotrexate (MTX) therapy have been reviewed. A total of 134 liver biopsies were performed. The lack of correlation between alcohol intake and the use of potential hepatotoxic drugs with pretreatment liver biopsies is noted. A review of 30 patients who had liver biopsies performed before and after MTX treatment showed no statistically significant difference between the histological grades before and after treatment. Nor was there any absolute correlation between the cumulative MTX doses and the histological changes of follow-up biopsies. In this group of patients, 15 (50%) developed fibrosis, which was severe in 2 patients, after 3,431 mg MTX average dose. Cirrhosis was observed in 3 patients (10%) after 1,667 mg MTX average dose. Follow-up liver biopsies are recommended for patients treated with MTX.

Adolescent

An improved electrophoretic method for a screening program for haemoglobinopathies.

A method for a screening program for haemoglobinopathies in a starch agar gel mixed with saponin is presented. Normal and abnormal blood containing haemoglobins S, C, I, M Boston, D Punjab, beta thalassaemia major and beta thalassaemia minor, were applied, in a tray with the capacity for 100 samples. The electrophoresis was performed in 45 min using 300 V. This method offers special advantages for the examination of a large number of samples, using a small amount of whole blood and without the previous preparation of haemoglobin solution.

Electrophoresis, Agar Gel

Expression and isoforms of gp43 in different strains of Paracoccidioides brasiliensis.

Individual exoantigens from 13 Paracoccidioides brasiliensis isolates were obtained and tested against a panel of 50 sera from patients with paracoccidioidomycosis by immunodiffusion test. The index of positivity varied from 20 to 100% according to the isolate. When these exoantigens were analysed by SDS-PAGE, eight presented high amounts of the glycoprotein gp43, two presented small amounts and in three there was no detectable gp43. The eight isolates presenting high amounts of gp43 were submitted to isoelectric focusing, blotted to nitrocellulose membranes, and revealed by monoclonal and polyclonal anti-gp43 antibodies. Four gp43 isoform profiles were obtained: profile A presenting pIs of 6.0, 6.2, 6.6 and 7.0, profile B presenting pIs of 6.4, 6.8 and 7.2, profile C presenting pI > 8.5 and profile D, presenting pIs of 5.8, 6.2 and 6.6. In each pattern observed, a major band with a distinct pI was detected. Despite this variation, our results strongly suggest an epitopic conservation among all isoforms analysed, since all of them were recognized by anti-gp43 monoclonal antibodies.

Antibodies, Monoclonal