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Biomedical subjects

R Castillo

Publications and source records attributed to R Castillo.

At least 181 records · Page 10Linked to original sources
PubMed1980

Electrophoretic pattern of proteins in mammary gland neoplasias.

Protein pattern was studied using discontinuous polyacrylamide gel electrophoresis in 53 adenocarcinomas, 13 fibroadenomas and 66 samples of mammary tissue adjacent to neoplasias. Important differences were found in patterns of both types of neoplasias, the same as between malignant tissues and non neoplastic adjacent tissues. There seems to be a certain correlation between some protein pattern and NOS and lobular histological types. It was also observed that some protein patterns were more frequent in neoplasias with metastasis to axillary nodes and vascular invasion. On the other hand, there seems to be important correlation between some protein patterns and the presence of early tumoral activity after mastectomy that is present even in the absence of positive axillary nodes at the moment of surgery.

Adenocarcinoma↗
PubMed1977

Substrate selectivity of squalene synthetase.

Six 1-3H-labeled analogues of farnesyl pyrophosphate have been studied as potential substrates for yeast and rat liver squalene synthetases: 2-methylfarnesyl pyrophosphate (4), 3-demethylfarnesyl pyrophosphate (5), 7,11-dimethyl-3-ethyl-2,6,10-dodecatrienyl pyrophosphate (6), 6,7,10,11-tetrahydrofarnesyl pyrophosphate (7), 4-methylthiofarnesyl pyrophosphate (8), and 4-fluorofarnesyl pyrophosphate (9). Analogues 4 and 5 are enzymatically incorporated into 11-methylsqualene (10) and 10-demethylsqualene (11), respectively, even if no farnesyl pyrophosphate is added to the incubations. None of the other analogues gives nonpolar products with either the yeast or liver enzymes. No tritium is enzymatically released to the medium from any of the analogues, indicating that they are not accepted at the first (proton exchanging) site. The data rule out formation of dead-end presqualene pyrophosphate products with analogues as first, but not as second, substrates. Implications of these results for the enzyme active-site topology and mechanism are discussed.

Animals↗
PubMed1977

Inhibition of squalene synthetase by farnesyl pyrophosphate analogues.

The pyrophosphates of the following farnesol analogues have been synthesized: 2-methylfarnesol; 7,11-dimethyl-3-ethyl-2,6,10-dodecatrien-1-ol; 3-demethylfarnesol; 4-methylthiofarnesol; 7,11-dimethyl-3-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyl02-iodo-2,6,10-dodecatrien-1-ol; 7,11-dimethyldodeca-6,10-dien-2-yn-1-ol; phytol; 3,7,11-trimethyl-2-dodecen-1-ol; 3,7,11-trimethyldodecan-1-ol; and geraniol. The double bonds in all the above compounds were in the E configuration, except phytol, which was a 7:3 mixture of 2E and 2Z isomers. Each of the pyrophosphates inhibits the incorporation of labeled farnesyl pyrophosphate into squalene by a yeast enzyme preparation. Free alcohols and monophosphates are inactive. The analogues, listed in order of decreasing inhibitory strength, are, by kinetic analysis, competitive or mixed inhibitors. Irreversible inhibition is not observed. The results suggest that binding to the enzyme is primarily mediated by the pyrophosphate moiety assisted by relatively nonspecific lipophilic interactions. Decreasing the chain length and saturating double bonds severely reduces binding, while substitution at the 2,3, and 4 positions, and lengthening of the chain, is well tolerated.

Diphosphates↗
PubMed1977

HLA antigens in Forestier's disease, ankylosing spondylitis, and polyarthrosis of the hands.

HLA antigens were studied in three different groups of 50 patients each. These included (a) Forestier's disease, (b) ankylosing spondylitis, and (c) polyarthrosis of the hands. HLA typing included 12 specificities from locus A and 15 from locus B, the frequencies being compared to those in 700 normal controls. No significant differences were found in the frequency of distribution between the polyarthrosis patients and the normal population. In patients with Forestier's disease, B5 was increased, but this was not a significant difference. The antigen B27 was present in 94 per cent of patients with ankylosing spondylitis, confirming previous studies.

Adolescent↗
PubMed1977

Os odontoideum removed by a transoral approach.

A case of atlanto-axial dislocation secondary to the presence of an "Os Odontoideum" is reported in which there was no history or evidence of trauma before the onset of symptoms. The treatment of this unusual clinical condition is discussed.

Axis, Cervical Vertebra↗