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Biomedical subjects

J Ramírez

Publications and source records attributed to J Ramírez.

At least 127 records · Page 7Linked to original sources
PubMed1984

Isolation of the mitochondrial F1-F0 adenosine triphosphatase by Sepharose-hexylammonium chromatography: properties and reconstitution in liposomes.

Lauryl dimethylamino oxide, a zwitterionic detergent, was employed to solubilize the H+ ATPase from beef heart mitochondria. A simple preparation procedure has been devised to obtain F1-F0 based on a method described to purify F1 ATPase (M. Tuena de Gómez-Puyou and A. Gómez-Puyou, 1977, Arch. Biochem. Biophys. 182, 82-86) which consists of the selective adsorption of F1 to Sepharose-hexylammonium beads. The preparation showed approximately 18 bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis; 5 correspond to F1 subunits and the rest probably to the stalk and hydrophobic sector F0. The binding of [14C]dicyclohexylcarbodiimide to a low-molecular-weight component of this preparation was demonstrated. The F1-F0 complex was reconstituted into phospholipid vesicles which displayed ATP-Pi exchange and ATP-dependent 9-aminoacridine fluorescence quenching, both sensitive to proton channel inhibitors.

Adenosine Triphosphatases↗
PubMed1984

Adriamycin as an inhibitor of 11 beta-hydroxylase activity in adrenal cortex mitochondria.

Inhibition of 11 beta-hydroxylase activity was observed to be due to the interaction of adriamycin with adrenal cortex mitochondria. The inhibition of the enzyme was uncompetitive, with an apparent Ki of 100 microM, and was dependent upon the concentration of the drug and the time of incubation. Adriamycin increased the oxygen consumption of these mitochondria. EPR studies showed that adriamycin was reduced to a free radical semiquinone which served to shuttle electrons to oxygen, leading to an impairment in the reduction of cytochrome P450. It is suggested this may be the mechanism for the inhibitory effect of the drug on 11 beta-hydroxylase activity.

Adrenal Cortex↗
PubMed1984

Effect of histidine, cysteine, glutathione or beef on iron absorption in humans.

One hundred thirteen subjects participated in iron absorption studies in which histidine, cysteine, reduced glutathione or beef were administered with test meals. Increasing doses of histidine from 416 to 2080 mg did not affect the absorption of 2 mg of corn iron. Reduced glutathione significantly increased the absorption from nonheme and heme iron present in black beans, corn and hemoglobin. Increasing doses of either cysteine or glutathione produce the same trend in the increase of absorption from corn iron as that observed from beef. The results suggest that the effect of cysteine on iron absorption is similar in the peptide form and as a single molecule.

Absorption↗
PubMed1984

Susceptibility of different populations of Colombian Aotus monkeys to the FCB-1 strain of Plasmodium falciparum.

p6udies of susceptibility to the FCB-1 strain of Plasmodium falciparum from Colombia were conducted in three different groups of Aotus monkeys. The results indicated that Aotus trivirgatus griseimembra from the north of the Magdalena Valley were the most susceptible host. A. t. griseimembra from the central Magdalena Valley appeared to be less susceptible to infection, while Aotus monkeys from the eastern Andes were even more resistant to infection. Serum electrophoretic studies were not useful as indicators of resistance or susceptibility to infection. However, the presence of 58 chromosomes in monkeys from the east Andes, a karyotype not previously reported, may be an indicator for the resistance of these animals to the FCB-1 strain. Based on these results, it is possible to assume that Aotus monkeys from the eastern Andes region of Colombia may represent a new species of Aotus; further studies are needed to clarify its taxonomic status.

Animals↗
PubMed1984

[Incidence of cancer in a university hospital: analysis of 500 clinical autopsies].

In a series of 500 autopsies cancer was found to be the first cause of death (24.6 por 100), followed by infectious diseases (23.8 per 100), and vascular diseases (22.2 per 100). The most frequent kind of malignant tumors found were lung neoplasms (17.8 per 100), followed by leukemias (17.0 per 100) and digestive tract tumors (11.3 per 100). Metastases were produced most frequently by tumors of the lungs (82.6 per 100), liver (81.8 per 100) and digestive tract (64.2 per 100). Metastases were found mainly in the lymph glands and liver.

Adolescent↗
PubMed1981

[Clinicopathologic correlation in a series of 500 clinical autopsies (author's transl)].

Clinicopathologic correlation was analyzed in the primary diagnoses for a series of 500 clinical post mortem studies of 440 adults, 9 children aged 1-14 and 51 infants of perinatal age. The diagnoses were incorrect in 43% of all cases, of which 17% were important errors, 14% of relative importance and 12% of slight importance. There is an inverted relationship between the proportion of errors and duration of the hospital stay of the patients. This underlines the importance of clinical post mortem studies for control, improvement and better teaching methods in a hospital.

Adolescent↗