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Biomedical subjects

F Ramos

Publications and source records attributed to F Ramos.

At least 127 records · Page 7Linked to original sources
PubMed1988

Further specificity characterization of von Willebrand factor inhibitors developed in two patients with severe von Willebrand disease.

Circulating inhibitors against von Willebrand factor (vWF) that show the properties of heterologous IgG antibodies have been described in a few patients with severe von Willebrand disease (vWD). The present study provides further characterization of inhibitors from two patients with severe vWD. Inhibitors in both, like polyclonal rabbit antibody, detected all sizes of multimers and the complex structure of each multimer from platelets and plasma of normal individuals as well as from plasma of patients with IIA, IIB, and IIC vWD. Both inhibitors and the rabbit antibody reacted mainly with the intact 225-Kd vWF subunit and the 189-H and 140-Kd fragments in contrast to monoclonal antibodies specific for vWF fragments that detected a higher relative proportion of 176-Kd fragment. Furthermore, all these antibodies recognized fragment III, although one inhibitor and rabbit polyclonal antibody reacted poorly and the other inhibitor did not react at all with reduced fragment II of vWF digested with Staphylococcus aureus V-8 protease. These data suggest that although human inhibitors from severe vWD patients may behave, to some extent, as polyclonal heterologous antibodies against native vWF, the former show striking differences in their target specificity as well as a much broader specificity than that described for human factor VIII inhibitors.

Adult↗
PubMed1987

Carcinoid syndrome and intravenous cyproheptadine.

The anaesthetic management of a patient with the carcinoid syndrome is reported. Important cardiovascular complications occurred immediately after tracheal intubation and during manipulation of metastases. Hypertensive crises were controlled with intravenous cyproheptadine, although hypotension and drowsiness were observed due to its use.

Aged↗
PubMed1986

Amiodarone, phaeochromocytoma and cardiomyopathy.

The anaesthetic management of a patient with a phaeochromocytoma and cardiomyopathy is described. The control of dysrhythmias was the major problem. Ventricular dysrhythmias were treated with lignocaine, and intravenous amiodarone was used to control the supraventricular rhythm disturbances.

Adrenal Gland Neoplasms↗
PubMed1985

Mutations affecting the enzymes involved in the utilization of 4-aminobutyric acid as nitrogen source by the yeast Saccharomyces cerevisiae.

We present genetic evidence for the enzymes 4-aminobutyrate: 2-oxoglutarate aminotransferase (EC 2.6.1.19) and succinate-semialdehyde dehydrogenase [NAD(P)+] (EC 1.2.1.16) constituting the functional pathway for the utilization of 4-aminobutyric acid as a nitrogen source by Saccharomyces cerevisiae. We show that the pathway is induced by 4-aminobutyric acid and that the presence of the pathway enzymes probably requires the integrity of a positive control element.

4-Aminobutyrate Transaminase↗
PubMed1985

Mutation affecting the specific regulatory control of lysine biosynthetic enzymes in Saccharomyces cerevisiae.

A Saccharomyces cerevisiae mutant which exhibits a considerably increased cellular lysine pool has been isolated and characterized. Assay of enzymes of the lysine and arginine pathways shows that the mutation harboured by this mutant alters the specific repression of lysine but does not influence the general control of amino acid biosynthesis. Because it is recessive to the wild-type allele and acts pleiotropically on the synthesis of several lysine pathway enzymes, this regulatory mutation has been denominated lys80-1 (or lysR--1). It is believed to affect the synthesis or the structure of a factor which plays a negative role in the control of LYS gene expression.

Aldehyde Oxidoreductases↗
PubMed1985

[Effect of chlorpromazine on the graft versus host reaction].

The effect of chlorpromazine (CLZ) on the graft vs. host reaction (G.vs.H.r.) induced by the injection of parental immunocompetent cells to F1 hybrids was studied. Rats of one parental strain were immunized with 3 X 10(7) splenic nucleated cells from the other parental strain. The injection of 3 X 10(6) and 6 X 10(6) nucleated cells obtained from the spleen of these previously immunized rats to 21-day-old F1 hybrids induced a typical G.vs.H.r. The degree of the G.vs. H.r. was estimated 10 days after the injection of the parental cells by the splenic index (S.I.) and histological studies of the spleen. The administration of CLZ (30 mg/kg/day i.p. during 10 days) either to the donor or to the host inhibited the G. vs.H.r. The effect of CLZ was partially antagonized by the simultaneous administration of Bromocriptine (10 mg/kg/day i.p.) to F1 hybrids. An effect similar, although quantitatively smaller to that of CLZ was caused by the injection of Prolactin (Pro) 100 I.U./kg/day, i.p. to F1 hybrids. None of these drugs modified neither the lymphatic structure nor the S.I. of hybrids not inoculated with lymphoid cells. The rectification of the functions number of injected cells vs. S.I. allowed us to apply the statistical method of covariance to the different treatments used and to establish the degree of significance of the modifications produced by the drugs. In contrast to the profound inhibition of the G.vs.H.r. obtained when CLZ was administered to previously immunized donors, the effect of this drug was minor if the treatment was performed in nonimmunized donors. Splenic cells obtained from rats previously immunized with the other parental strain were incubated in vitro during two hours with different concentrations of CLZ (10(-6), 10(-5) and 10(-4) M) or Pro (15,30,50,75,100,200 and 500 ng/ml). This treatment did not modify the capacity of these cells to induce G.vs.H.r. when injected into F1 hybrids. We postulate that the inhibitory action of CLZ on the G.vs.H.reaction is mediated, at least in part, by the capacity of this drug to increase the plasmatic levels of PRO. The effect of CLZ and PRO is observed mainly in lymphoid clones in expansion because of the stimulation by histocompatibility antigens.

Animals↗
PubMed1982

Occurrence of a catabolic L-serine (L-threonine) deaminase in Saccharomyces cerevisiae.

Saccharomyces cerevisiae mutants lacking the anabolic L-threonine deaminase, the ilv1- mutants, have been found to exhibit a normal ability to grow, without auxotrophy towards isoleucine, on L-threonine of L-serine as only nitrogen nutrient. Starting from a strain carrying a ilv1- mutation, a new mutation affecting the ability to utilize L-threonine as nitrogen source was selected. This mutation, which also impairs the ability to utilize L-serine, has been denominated cha-, for 'catabolism of hydroxyamino acids' and was found to result in the lack of a catabolic L-serine (L-threonine) deaminase. This enzyme which, unlike the anabolic threonine deaminase, is more active towards serine than towards threonine, differs from the latter enzyme by a number of biochemical and regulatory properties. Whereas the anabolic enzyme is an allosteric enzyme sensitive to feedback inhibition by isoleucine, the catabolic enzyme exhibits Michaelian kinetics: no control of its activity has been detected. Its synthesis is induced by L-serine and L-threonine. These two enzymes, which thus can be easily differentiated by means of their regulations, display a limited ability to compensate for one another's absence and appear to play clearly distinct roles under normal physiological conditions.

L-Serine Dehydratase↗
PubMed1981

[Transitory IgM monoclonal gammopathy associated with brucellosis and tuberculosis (author's transl)].

Two cases of transitory IgM monoclonal gammopathy associated with infectious disease are presented. One patient was a 29 year-old woman with acute brucellosis; electrophoresis showed a homogeneous spike of slow gamma mobility constituted of IgM lambda. The second case was a 52 year-old male with milliary tuberculosis, in whom a homogenous spike of rapid gamma mobility constituted of IgM kappa was found. The monoclonal component disappeared in both cases after treatment of the infections; at 2 and 21/2 months respectively. The fact that the association of transitory IgM paraprotein and infection is not common, especially with brucellosis, is commented upon and a direct relationship between the infection and the monoclonal component is suggested.

Adult↗
PubMed1981

[High density lipoprotein cholesterol. Normal values, influence of vascular risk factors and of a vegetarian diet (author's transl)].

The serum levels of cholesterol bound to high density lipoproteins (HDL-C) were determined by the heparin-manganese chloride precipitation method in 306 subjects, 182 male with ages ranging from 11 to 81 years, and 124 female with ages ranging from 7 to 78 years. Twenty six subjects belonged to a lacto-vegetarian community, while the remaining 280 were healthy volunteers, factory workmen sampled during a regular check-up, and either outpatients or inpatients being evaluated for minor illnesses or minor surgery. None of the subjects had arteriosclerosis or a metabolic disease and, with the exception of the lacto-vegetarians, they were all consuming a normal diet. HDL-C concentrations varied very little among the different age groups. Females had HDL-C values slightly superior to those of males. No significant differences were found between smokers and non-smokers, alcohol drinkers and non-drinkers, and regularly exercising and sedentary people. HDL-C concentrations were independent of total cholesterol and triglyceride levels. Females under oral contraceptive treatment had lower HDL-C levels than control females, but the differences were not statistically significant. Compared with age and sex-matched controls, the lactovegetarians showed similar HDL-C concentrations.

Adolescent↗