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Biomedical subjects

C Zapata

Publications and source records attributed to C Zapata.

At least 37 records · Page 2Linked to original sources
PubMed1993

On the detection of nonrandom associations between DNA polymorphisms in natural populations of Drosophila.

The capacity to detect nonrandom associations between restriction-map variants was examined in eight gene regions of Drosophila melanogaster (yellow-achaetescute, white, Zw, Adh, Est6, and rosy) and D. pseudoobscura (Adh and Xdh), on the basis of published population data. The statistical power from individual pairwise tests was both heterogeneous and generally low across gene regions. Sample sizes larger than those currently being used are needed to ensure any power to detect disequilibrium by individual tests. It is found that the heterogeneity in power is mostly explained by large differences in the intensity of sample disequilibrium among regions. The yellow-achaete-scute, Zw, and Adh loci of D. melanogaster displayed both the highest mean power (approximately 0.4) and a very great disequilibrium (mean absolute values of D' were 0.8-1). By contrast, all the other gene regions exhibited lower mean power (approximately 0.2) and moderate levels of disequilibrium (0.4-0.6). Although the proportion of significant pairwise associations, especially for white, Est6, and rosy in D. melanogaster and for Adh and Xdh in D. pseudoobscura, is more or less close to the type I error, simultaneous-inference significance tests show that gametic disequilibrium is occurring at the eight DNA regions examined.

Alcohol Dehydrogenase↗
PubMed1990

Genetic variation in a modifier system affecting the expression of bare mutant of Drosophila subobscura.

Genetic variation affecting the expression of Bare (Ba), a morphological mutant of Drosophila subobscura that reduces the number of bristles and is located on the O chromosome of this species, is reported. Our results show that O chromosomes extracted from a natural population (El Pedroso, Santiago de Compostela, Spain) show considerable genetic variation in modifier effect upon Ba expression. The amount of modifier variability is dependent on the chromosomal arrangement (OST and O3 + 4 + 7), since modifier variation is higher in OST than in O3 + 4 + 7 chromosomes. Investigations of the genetic architecture of this modifier system on the O chromosome carried out using biometrical methods indicate that a relatively small number of genetic "factors" can explain the differences in modifier effect between a wild O chromosome of high modifier effect and a marker chromosome of low score. In addition, the modifier effects show a non-uniform distribution along the O chromosome and some indication of clustering of modifier "factors" around the major locus (Ba) is also observed.

Analysis of Variance↗
PubMed1990

[Use of a specific DNA probe to confirm sickle cell anemia in a caucasian woman].

A specific DNA probe containing part of the structural B-globulin gene was used to confirm the diagnosis of sickle cell anemia in a caucasian woman. The patient's genomic DNA was digested with the restriction endonuclease Dde I, fractioned by agarose electrophoresis and Southern blotting. Molecular hybridization was performed with the DNA probe prepared by chemical labelling with photobiotin. The beta 8/beta 8 genotype rendered only 1 fragment of length 376 bp. Upon digestion with Dde I, the DNA of an individual with the normal genotype containing the enzyme recognition sequence at the site of sickle cell mutation, resulted in 2 fragments of 201 and 175 bp. The pedigree of the patient's caucasian family was studied by Hb electrophoresis. Four out of 7 brothers carried the sickle cell trait.

Adult↗
PubMed1990

[Second neoplasms in malignant hematologic disorders. Experience from 1978 to 1987].

Neoplasia may develop in patients with malignant hematologic disorders, during remission after radio and/or chemotherapy. A multifactorial origin related to therapy may be postulated. From 1978 to 1987, among 142 patients with malignant hematologic disorders (Hodgkin lymphoma 33, non-Hodgkin lymphoma 51, Multiple Myeloma 35 and Chronic Myeloid Leukemia 31) we observed 3 patients developing another neoplasia. An additional patient with acute non-lymphatic leukemia had been submitted to chemotherapy for gastric cancer. Four other patients with double neoplasia, one of them a hematologic one, had not been submitted to chemotherapy. The lack of national registries for neoplastic diseases precludes an estimation of the odd ratios involved in our findings.

Adolescent↗
PubMed1990

[Lymphomas of the parotid region].

Parotid gland lymphomas are very uncommon. Two patients with this condition were treated in the last decade. Surgery should be used only for diagnosis and becomes unnecessary when adenopathy is present, since a lymph node biopsy will establish the diagnosis.

Adolescent↗
PubMed1988

Farm animal feeders: another group affected by cereal flour asthma.

Asthma induced by cereal flour is a long recognized entity. We present studies of three patients affected by asthma related to exposure to cereal flour contained in animal formula feeds. Skin prick test performed with the formula feed components showed positive reactions to cereal flours (wheat, rye and barley) and negative to the other substances in these formulas. Specific anti-wheat, rye and barley flour IgE antibodies were found by RAST. Bronchial provocation tests (BPT) with wheat flour (patients 1 and 2) and barley flour (patient 3) all showed immediate responses. These findings suggest that our patients' symptoms were caused by an IgE-mediated hypersensitivity to cereal flours from animal formula feeds. We call attention to the importance of cereal flours in animal formula feeds as a cause of occupational asthma in farm and animal feeders.

Adolescent↗
PubMed1988

Severe anaphylactoid reaction to nalidixic acid.

We present the case of a 58-year-old non-atopic woman who suffered an adverse reaction to orally administered nalidixic acid, which had been prescribed for the treatment of a urinary tract infection. The single-blind oral provocation test was positive; the patient presented the clinical features of an anaphylactoid reaction 3 min after administration of nalidixic acid. Both the skin test and the histamine release test were negative. These results suggest that we are dealing with an anaphylactoid reaction not described before with this drug.

Anaphylaxis↗
PubMed1986

Immune thrombocytopenic purpura associated with hepatitis A.

A 23-year-old man developed thrombocytopenic purpura at the end of the second week of the clinical evolution of hepatitis A confirmed by viral markers. The bone marrow of this patient showed megakaryocytic hyperplasia. Circulating in his serum immune complexes were demonstrated by solid phase conglutinin enzymo-immunoassay. Platelet-reactive serum factors were also detected by an indirect immunofluorescence test using fresh donor platelets as targets. The evolution of both the hepatitis and the purpura were benign with no therapy other than bedrest. Platelet count normalized within five weeks of the onset of purpura, and IgM antibodies against hepatitis A virus as well as circulating immune complexes dropped to normal levels. It is postulated that the thrombocytopenia of this case was caused by nonspecific deposition of immune complexes at the platelet surface.

Adult↗
PubMed1985

Cell markers and acute leukaemia subtypes in Chile.

A panel of monoclonal antibodies were used to define acute myeloblastic leukaemia (AML) and acute lymphoblastic leukaemia (ALL) with its different subgroups. Thirty-three patients were studied in a period of one year. ALL was diagnosed in 80% of the children and 20% of the adults. AML was present in 22% of the children and 78% of adults. In children, only one of seven was common ALL, three of seven were T-ALL and three of seven were B-ALL. Five of 12 were unclassifiable (U-ALL). In adults the 4 ALL were U-ALL.

Adolescent↗