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R Caballero

Publications and source records attributed to R Caballero.

34 records · Page 2Linked to original sources
PubMed1992

Effects of X-linked hemoglobin on in-vitro platelet function.

The in-vitro function of platelets in 1:1 mixtures of fresh whole blood and 10% DBBF alpha-alpha cross-linked hemoglobin in Ringer's acetate buffer was assessed by quantitative aggregation after challenge with common agonists and compared to the function of platelets in similar dilutions of whole blood in saline. Whole blood aggregometry was performed after addition of ADP, collagen, and ristocetin. Aggregation was quantified by measuring the change in impedance as drawn on the chart recording. No difference in mean impedance change was noted between the groups of blood samples which were incubated and tested in the hemoglobin solution and those incubated and tested in saline. In addition, incubation and stirring of the above mixtures over a period of six minutes without the addition of agonists did not result in spontaneous platelet aggregation. We conclude that alpha-alpha cross-linked hemoglobin, in the concentration studied, does not affect in-vitro platelet function, as measured by whole blood aggregometry.

Aspirin↗
PubMed1992

Effect of various microbial preparations on P-388 mouse lymphocytic leukemia.

Four bacteria-derived immunopotentiators were tested for their protective effect on a P-388 mouse lymphocytic leukemia model. The microbial test products were prepared from the following bacterial strains: ATCC 35983 Staphylococcus epidermidis isolated from a patient with IV catheter; ATCC 31874, a patented strain listed as Staphylococcus epidermidis isolated from the urine of a cancer patient; ATCC 25615 Staphylococcus hominis obtained from a child with lymphocytic leukemia, and ATCC 25614 Staphylococcus warneri, an isolate from a patient with adenocarcinoma of the breast. A limited degree of protection and prolongation in survival time was observed in the animal group treated with the bacterial strain ATCC 31874.

Adjuvants, Immunologic↗
PubMed1989

[Changes in the ovarian flow during the menstrual cycle: an echo-Doppler study].

The results of the velocimetric evolution of the ovarian flow with pulsed Doppler in 15 normal ovulatory cycles are presented. During the follicular phase the blood flow velocity waveforms (FVW) of the dominant ovary presented a progressive albeit non significant increment of its conductance. This rise was not confirmed in the contralateral ovary. After the echographic ovulation the ovarian FVW showed qualitative and quantitative modifications that determine its "luteal conversion". The conductance index (D/S x 100) was significantly higher (p less than 0.001) during the luteal phase than during the follicular and in the contralateral ovary. The luteal conversion of the ovarian FVW is proposed as a new criteria of ovulation and luteal function.

Adult↗
PubMed1988

Conformational alterations detected by circular dichroism induced in the normal ras p21 protein by activating point mutations at position 12, 59, or 61.

Activation of the oncogenic potential of ras oncogenes occurs by point mutations at codons 12, 13, 59, 61, and 63 of the sequences that codify for its product, a 21-kDa protein designated as p21. This activation has been postulated by computer models as modifiers of the structure of the protein, which may alter its biochemical and biological activities. We have expressed in bacteria the normal ras p21 and five mutated p21 proteins with mutations at positions 12, 59, 61, 12 plus 59, and 12 plus 61. Purification was carried out by solubilization from bacterial pellets in 7 M urea and chromatography through a Sephadex G-100 column to obtain greater than 95% purified proteins. Circular dichroic (CD) spectra showed that the normal protein and that activated by substitution of Ala59 to Thr59 are very similar in their overall structure. By contrast, point mutations affecting either 12 or 61 residues substantially altered the structure of the proteins. When the parameters of Chen et al. [Biochemistry II, 4120-4131 (1972)] were applied to the CD spectra, both normal and thr59-mutated ras proteins showed a less organized structure than mutated proteins at position 12 or 61. Since the Thr59 mutant has more similar transforming activity than other activated proteins, but a GTPase activity similar to that of the normal protein, our results support the hypothesis that there is more than one mechanism of activation of the ras p21 protein. One of these mechanisms involves important structural alterations by point mutations at position 12 or 61 which reduce the GTPase activity of the protein. Another mechanism will be that induced by a substitution of Ala59 to Thr59 which does not substantially alter the protein conformation. A putative alternative mechanism for the activation of this mutant is discussed.

Cell Transformation, Neoplastic↗
PubMed1987

Spectroscopic studies on the structural organization of the lectin discoidin I: homologies with fibronectin.

The structure of the lectin discoidin I has been studied by circular dichroism and fluorescence spectroscopy. A positive ellipticity band at 224 nm is detected in the CD spectrum of discoidin I. The fluorescence spectra show a defined shoulder at 325 nm that through acrylamide quenching has been associated with a displaced tryptophan residue partly buried in the discoidin I molecule. This tryptophan could also be responsible for the 224 nm positive band of the CD spectrum. These spectroscopic characteristics of discoidin I indicate the existence of structural homologies with fibronectin, where the optical activity of aromatic chromophores has been associated with the positive ellipticity band at 227 nm. The CD adjust parameters and theoretical secondary structure predictions show that discoidin I is a molecule with a low content of alpha-helix and beta-strand and high content of beta-turn structures, similar to other lectins.

Circular Dichroism↗
PubMed1987

Influence of carboxyl groups on conformation of histone H1 from Ceratitis capitata.

Salt and pH-dependent effects on the local conformation of the two tyrosine residues of the histone H1 from the fruit fly Ceratitis capitata have been studied by difference spectroscopy, circular dichroism (CD), fluorescence emission and quenching of tyrosine emission by KI. Four different solvent conditions were used: pH 1.0 and pH 6.0 in the presence or absence of 1 M NaCl. The results clearly indicate a partial folding of the fruit fly histone H1 in the absence of NaCl upon pH increasing from 1.0 to 6.0. This folding is achieved only through ionization of acidic side chains which leads to an environment of the tyrosine residues similar to that found in salt-folded histone H1. Furthermore, the present results give new insights into the states of the tyrosine residue responsible for the tyrosinate-like fluorescence emission at 340 nm described previously (Jordano, J., Barbero, J.L., Montero, F. & Franco, L. (1983) J. Biol Chem. 258, 315-320).

Animals↗
PubMed1986

Localization of the high affinity calcium-binding site on tubulin molecule.

Tubulin is a calcium-binding protein. Two different modes of interaction of calcium with tubulin have been described: a high affinity interaction to one or two binding sites and lower affinity interactions to several other binding sites. In the present study, we have used limited proteolysis of tubulin with trypsin, chymotrypsin, and subtilisin to localize the high affinity calcium-binding sites. Our results indicate that two sites are located in the carboxyl-terminal region of both tubulin subunits, and that tubulin deprived of its carboxyl-terminal region is able to polymerize in the presence of 0.5 mM calcium.

Amino Acid Sequence↗
PubMed1985

Kinetics of conformational changes in the globular head of calf thymus H1 upon tryptic digestion.

The influence of the N- and C-terminal tails on the conformation of the globular domain of histone H1 from calf thymus has been investigated by monitoring the changes in absorption far UV circular dichroism and fluorescence spectra due to the tryptic digestion of the molecule. The values of kinetic constants obtained for the time course of the reaction followed by different above mentioned techniques seem to indicate that whereas the relaxation in the tyrosine environment occurs due to the digestion of the polar tails, the alpha-helix content increases in the earlier phase of the digestion.

Animals↗
PubMedDate not supplied

[Subjective experience and quality of life in schizophrenia].

The term quality of life has been gradually introduced in the field of Psychiatry. This term tries to integrate not only the symptoms in Psychiatric patients, but also other aspects, like individual perceptions, personal expectations, degree of independence, etc., in order to achieve a global understanding of the patient. The are few studies on quality of life in schizophrenia, especially there is a lack of self assessment scales that the patients can fill out about themselves and their psychological environment. The Seville Quality of Life Questionnaire tries to evaluate the subjective experience of patients with schizophrenia about their illness. The Seville Quality of Life Questionnaire also checks the presence or absence of groups of patients with schizophrenia with a better or worst quality of life. We have assessed 222 subjects that meet ICD-10 criteria diagnostic for schizophrenia, with the Seville Quality of Life Questionnaire, the Positive and Negative Symptom Scale specific psychopathology scale and the AMDP system general psychopathology scale. Our results show two clearly differentiate groups: one with better (Group 2: 108 patients) and one with worse (Group 1: 81 patients) quality of life. However, 33 patients could not be included in any of the two groups. In the worse quality of life group the most prominent factors were: lack of cognitive grasp, perplexity, fear of loss of control, and contained hostility. These four factors have a great influence on the worse quality of life. When we compare the Seville Quality of Life Questionnaire data with several the Positive and Negative Symptom Scale scores, we saw that the group of worse quality of life presents higher scores on both Negative and Positive Symptoms of schizophrenia, and also in the Positive and Negative Symptom Scale general psychopathology scale. In the AMDP system general psychopathology scale we saw three groups of significant symptoms in the Seville Quality of Life Questionnaire: 1. Difficult relationships with the external world, 2. Difficulty to understand what it happening (loss of associations); and 3. Affective alterations (ambivalence).Finally, these data suggests that it is probable that the Seville Quality of Life Questionnaire could be able to build a typology of patients with schizophrenia more centred in their pathology that in their psychophatology.

Adult↗
PubMedDate not supplied

Hysteroscopy: an analysis of 2-years' experience.

BACKGROUND: Over the years, hysteroscopy has been increasingly performed for various gynecological disorders. In this study, we present a review of hysteroscopic procedures performed over a 2-year period analyzing the complications associated with it. METHODS: Seven hundred twenty-six hysteroscopic procedures performed at the Department of Gynecology and Obstetrics, University of Kiel over a period of 2 years were reviewed retrospectively using the GynReg database in the department. Indications, intraoperative diagnoses, and complications were particularly highlighted. RESULTS: The most common indications for the procedure were abnormal vaginal bleeding, endometrial ablation, polypectomy, and myomectomy. The most common findings were uterine polyps, submucous myoma, and hyperplastic endometrium. The complication rate was 1.65% of total hysteroscopies. False passage and uterine perforation were the most common acute complications. No late complications occurred. CONCLUSIONS: Correlating our data with that found elsewhere, we find hysteroscopy to be a safe, minimally invasive procedure with a very low rate of complications.

Female↗
PubMedDate not supplied

[The echo-dobutamine pharmacological stress test in ischemic cardiopathy].

We report our experience with Echo-Dobutamine stress test. In order to evaluate the sensitivity, specificity and the safety, of the pharmacologic echo-dobutamine stress test, we studied 30 patients with ischemic heart disease based on clinical history, 2D echocardiogram, standard exercise stress test and cardiac catheterization. The test was started under continuous videotape of the segmental left ventricular motility on the conventional views. Dobutamine was administer intravenously 2.5 to 40 micrograms/kg/min every 3 minutes, the mean higher dobutamine dose was 19 +/- 14.3 micrograms/kg/min, having a continuous electrocardiographic monitoring of the heart rate as well as blood pressure. The myocardial motility was recorded with each increment in the dobutamine dose. Among the cases, 22 were males and 8 females with an average age of 55 +/- 9 years. Twenty two patients had history of remote myocardial infarction and were asymptomatic at the moment of the test; 8, who had angina pectoris were on a functional class I-II of the CCS. The mean basal ejection fraction was 62.6 +/- 11.7% by echo vs 64.4 +/- 16.8% obtained by cardiac catheterization (p no significant). There were no arrhythmias in any case. The heart rate increased from 68.7 +/- 10.1 to 85.5 +/- 15.7 beats per minute (p < 0.001). The systolic B/P was increased from a mean of 124 +/- 14.5 to 138.3 +/- 14.4 mmHg (p < 0.0005) while the diastolic pressure varied from 82.3 +/- 8.2 to 90.8 +/- 9.6 mmHg (p < 0.001). There were no severe complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗