Biomedical subjects
Publications and source records attributed to M Molina.
Hemofiltration is a relatively new and interesting form of treatment for patients with end-stage renal disease. This review considers this new modality for the pediatric patient and compares it with hemodialysis.
Yeast cells of Candida albicans 1001 produced glucan-hydrolysing activity, most of which was due to an exo-1,3-beta-glucanase. The enzyme was periplasmically located; it could be found in culture medium samples, and was secreted by protoplasts when cultured under regeneration conditions. In contrast to most yeast exoglucanases, this enzyme was practically inactive against p-nitrophenyl-beta-D-glucoside, hydrolysis of this substrate being carried out by a beta-glucosidase located inside the cytoplasmic membrane and not secreted to the external medium. Supernatant fluids from cell-free extracts reached their maximum glucanase level after several days at 0 degrees C, suggesting that the active enzyme was formed from an inactive precursor. Glucanase activity substantially decreased and sometimes disappeared from the cells when the yeast-to-mycelium transition was induced, but a significant (though lesser) reduction was also observed in yeast cells incubated in the same medium under conditions (temperature, cell concentration) that did not lead to formation of hyphae. It is suggested that C. albicans exo-1,3-beta-glucanase may not be necessary for mycelial growth.
Salts of metals which are carcinogenic, noncarcinogenic, or of unknown carcinogenicity were assayed for their abilities to modulate ultraviolet (UV)-induced mutagenesis in Escherichia coli WP2. In addition to the previously reported comutagenic effect of arsenite, salts of three other compounds were found to enhance UV mutagenesis. CuCl2, MnCl2 (and a small effect by KMnO4), and NaMoO4 acted as comutagens in E coli WP2, which has wild-type DNA repair capability, but were much less comutagenic in the repair deficient strain WP2s (uvrA). The survival of irradiated or unirradiated cells was not affected by these compounds. No effects on UV mutagenesis were seen for 16 other metal compounds. We suggest that the comutagenic effects might occur either via metal-induced decreases in the fidelity of repair replication or (in the case of CuCl2) via metal-induced depurination.
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Two cases of trisomy 9p are presented. The different cytogenetic mechanism given in these cases shows us that with independence of it, it exists a triplication of the half distal short arm of chromosome 9 which gives specificity to these phenotypic features. It might be a possible meiotic origin of the chromosomic rearrangement on both translocations, the formation of satellited chromosomes and isochromosomes of the short arm on chromosome 9 and the consequently wrong segregation of each one of them. The non-existence of chromosomic material with activity in the transcription, confers to both situations the category of a pure trisomy 9p. The prenatal diagnosis through amniocentesis might be useful, even in the so called "de novo" cases, in order to avoid the repetition of this kind of structural aberration or some others that could appear due to fragility of certain chromosomic regions.
A number of metal compounds have been shown to be human carcinogens. Others, while not proven human carcinogens, are able to cause tumors in laboratory animals. Short-term bacterial assays for genotoxic effects have not been successful in predicting the carcinogenicity of metal compounds. We report here the ability of some metal compounds to cause the induction of lambda prophage in E coli WP2s(lambda). By far the strongest inducing ability was observed with K2CrO4, followed by Pb(NO3)2 greater than MnCl2 greater than Ni(OOCCH3)2 greater than CrCl2 greater than NaWO4 greater than Na2MoO4 greater than KMnO4. With the exception of chromate, long-term exposures in a narrow, subtoxic dose range were required in order to demonstrate phage induction. A new microtiter assay for lambda prophage induction, which incorporates these features, is described. This system also was able to detect very small amounts of organic carcinogens.
Authors present a new case of campomelic dysplasia associated to true hermaphroditism. Clinical and radiological findings are described. Ethiopatogenical factors are widely discussed, and special correlation between campomelic dysplasia and sexual reverse, is noted, according to new concepts on H-Y antigen. Differential diagnosis with neonatal chondrodystrophies associated with respiratory distress and congenital incurved extremities are also reviewed.
Isobutyl nitrite is an effective nitrosating agent at acidic, neutral and basic pH in the presence of species arising from phosphate ion. The reaction is first-order in isobutyl nitrite and amine. In the reaction of isobutyl nitrite with sulfanilamide, the pH dependence reflects the change in concentration of the various protonated forms of phosphate, with H3PO4 and H2PO4- most strongly affecting the rate. In the reaction of isobutyl nitrite with dipropylamine, the pH dependence also reflects the change in the concentration of unprotonated amine.
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Rat liver S9 preparations contain material which causes enhancement of UV mutagenesis in Escherichia coli WP2. This comutagenic activity is present in S9 preparations from both uninduced and Aroclor-induced rats. Strains of E. coli which are defective in the uvr-dependent excision repair pathway fail to show comutagenic action by S9. The comutagenic material is heat-labile and non-dialyzable, suggesting that it might be protein. This differs from the small amount of mutagenic material present in rat liver S9, as the latter is dialyzable and can be demonstrated in the repair-deficient strain E. coli WP2s (uvrA).
We present a case of a child with important phenotypic abnormalities (retinoblastoma, hypoplasia of the thumbs and genital), as well as craneofacial and evident psychomotor retardation. The chromosomal study showed a interstitial delection of the long arms of a chromosome from D group. We try to correlate karyotypes and phenotype, telling about difficulties that this relation means insisting about the importance of knowing more cases of chromosome 13 delection. We also think that subbands analysis represents an important factor in this correlation.
Two patients with the clinical diagnosis of ataxia-telangectasia are reported. Both had a mixed partial immunodeficiency characterized by selective absence or deficiency of IgA and anergy to cutaneous antigens. During the course of their disease both patients developed a poorly differentiated lymphocytic lymphoma of intraabdominal location. One of the patients died from infectious complications after receiving the first course of chemotherapy, while the second one remains alive under treatment. The high incidence of lymphoreticular neoplasms in early life in these patients with a genetically deficient immune system is commented upon along with the fact that, in spite of that, the pathogenesis of the syndrome remains unknown.
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