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Biomedical subjects

G Bravo

Publications and source records attributed to G Bravo.

At least 73 records · Page 4Linked to original sources
PubMed1993

Impact of knee extensor strength deficits on stair ascent performance in patients after medial meniscectomy.

After arthroscopic meniscectomy the relationship between the magnitude of knee extensor strength deficits and locomotor performance during stair ascent unloaded and when carrying a 22 kg load has been tested in 31 patients. The specific locomotor adaptations related to large strength deficits were also studied. The results indicate that large deficits were significantly associated to: 1) reduced activation of the knee extensor muscles (vastus medialis and lateralis) during the first double leg support and single leg support phases, and of the hip extensors (medial hamstrings) during the second double leg support of stair ascent, 2) overactivations of the hip extensors (gluteus maximus and medial hamstrings) during single leg support, and 3) longer cycle and step durations and lower cadences. Locomotor abnormalities in movements and muscle activations were generally found in patients with strength deficits greater than 25% while patients with smaller strength deficits (less than 25%) usually could climb stairs with normal performance. These results support the use of knee extensor strength measures to predict locomotor capacities, and also highlight the importance of postoperative knee strength rehabilitation.

Adaptation, Physiological↗
PubMed1992

Neurosurgical experience with tumours of the pineal region at Clinica Puerta de Hierro.

The clinicopathological experience with 50 cases of pineal region tumours at Clinica Puerta de Hierro is presented. In this series, 88% of the patients were evaluated by CT-scan. Pineal region tumours make up approximately 0.7% of the intracranial expansive processes in the Spanish population. The largest group of lesions appearing in this localization is that of the germinomas (38%), followed by nontumoural lesions (20%) and tumours generally considered to be of the vicinity, such as meningiomas, gliomas and metastases (18%), tumours of the pineal parenchyma (14%), and non-germinoma germinal tumours (10%). In our series, in addition to an intracranial hypertension syndrome, an ophthalmological and, to a minor degree, an endocrinological syndrome predominate in germ-cell tumours, with a cerebellar syndrome appearing in gliomas of the pineal region. All the patients in the series diagnosed as having a germinoma and treated by irradiation are alive, and free of disease, after follow-up ranging from 2 to 20 years (mean: 8 years). The experience obtained with the present series supports the opinion that, in radiosensitive tumours, surgical resection adds no therapeutic benefit to treatment with radiotherapy alone. We suggest that when dealing with a tumour of the pineal region, CT-scan and clinical assessment now permit an initial selection of patients susceptible to surgery as a first therapeutic option, indicating those patients who, because they are considered to have either a "probable germinoma" or a "tumour of uncertain diagnosis", should undergo stereotaxic biopsy or trial radiotherapy and, only when this has proved a failure, should be subjected to open surgery.

Adolescent↗
PubMed1992

An acute remission of Reiter's syndrome in male patients treated with bromocriptine.

We describe 4 male patients with Reiter's syndrome treated with bromocriptine. All 4 had infectious gastroenteritis and chronic Reiter's syndrome with arthritis and enthesopathy that persisted despite treatment in 3 with antiinflammatory drugs and 1 with sulfasalazine for long periods. In all patients treatment was cancelled 8 days before bromocriptine treatment. In 2 patients a dramatic improvement was observed 24 h after 2.5 mg/day of bromocriptine. Two patients improved after 4 days of bromocriptine treatment (5 mg/day). All 4 patients remained asymptomatic for at least 4 months of bromocriptine treatment. Bromocriptine may be useful for treating male patients with Reiter's syndrome.

Adult↗
PubMed1991

Estimating the reliability of continuous measures with Cronbach's alpha or the intraclass correlation coefficient: toward the integration of two traditions.

The epidemiological literature has been ambiguous concerning reliability estimates for continuous variables. Reproducibility and internal consistency have been presented as different aspects of reliability, the former being estimated with some form of intraclass correlation coefficient, the latter with Cronbach's alpha. Based on demonstrations available in the literature this paper recalls that both estimates are based on the same measurement model and on the same definition of reliability. It also highlights the conditions under which they are equivalent and provides practical suggestions concerning the estimation of reliability, based on design considerations.

Analysis of Variance↗
PubMed1991

Intertrial reliability of work measurements recorded during concentric isokinetic knee extension and flexion in subjects with and without meniscal tears.

Intertrial reliability of work measurements was studied in 19 men with a partial medial meniscal tear (ME group) and in 10 men with no history of knee injury (control group). Three maximal voluntary concentric contractions of the muscles involved in knee extension (KE) and knee flexion (KF) were performed on a dynamometer at 30 degrees and 180 degrees/s using a preloading protocol. The subjects moved their legs through an arc of 90 degrees, and the work produced in the constant-velocity phase between 70 and 20 degrees of KE was computed for each trial. In ME group subjects able to perform three consecutive contractions (n = 12-14), high intertrial intraclass correlation coefficients (ICCs) were found (ICCs = .86-.92), except for KE work measurements at 180 degrees/s (ICC = .67). In the control group subjects, high ICCs were obtained for KE work measurements (ICCs = .87 and .95), whereas the low ICCs obtained for KF work measurements (ICCs = .64 and .79) increased to .86 and .93 when the first trial was removed. In both groups, a significant increase was found over the trials for KF measurements at 180 degrees/s and KE measurements at 30 degrees/s, but work measurements were shown to peak at the second trial. The results of this study suggest that the work produced on the second trial reflects a subject's maximal capacity. [Durand A, Malouin F, Richards CL, Bravo G. Intertrial reliability of work measurements recorded during concentric isokinetic knee extension and flexion in subjects with and without meniscal tears.

Adult↗
PubMed1991

Postnatal maturation of excitation-contraction coupling in rat ventricle in relation to the subcellular localization and surface density of 1,4-dihydropyridine and ryanodine receptors.

To better understand excitation-contraction coupling in cardiac muscle, we investigated the main Ca2+ channels involved in that process in adult and neonatal rat ventricle. Voltage-dependent (L-type) Ca2+ channels and sarcoplasmic reticulum Ca2+ release channels were labeled by means of [3H] (+)-PN200-110 and [3H]ryanodine, respectively. The number of [3H]ryanodine binding sites (per gram tissue) increased more than that of [3H] (+)-PN200-110 binding sites over the postnatal period (2.1-fold versus 1.35-fold, respectively). After equilibration of microsomal fractions in density gradient, ryanodine receptors were characterized by a heavy distribution pattern that did not change appreciably between days 1 and 30 after birth. In neonatal tissue, 1,4-dihydropyridine receptors were found mainly in low-density subfractions, together with other sarcolemmal constituents, whereas in adult tissue, they were recovered predominantly in high-density subfractions, together with ryanodine receptors. Thus, after birth, and in parallel with the development of T tubules, there was a progressive concentration of L-type Ca2+ channels in junctional structures of high equilibrium density, where they were situated close to the Ca2+ release channels of the sarcoplasmic reticulum. In adult ventricle, L-type channels were, on an average, threefold more abundant in T tubules than in external sarcolemma. In parallel mechanical studies, we found that the inhibitory action of ryanodine on systolic contraction was much more pronounced in adult than in neonatal right ventricle, and that, conversely, neonatal tissue was more sensitive that adult tissue to inhibitors of L-type channels. We conclude that, in view of the presumed mechanism of Ca2+ release from the sarcoplasmic reticulum, that is, Ca(2+)-induced Ca2+ release, the predominant localization in adult rat ventricle of the major Ca2+ entry pathway in the vicinity of the Ca2+ release pathway is of great functional significance. Furthermore, owing to the relative stoichiometry of Ca2+ entry and Ca2+ release channels in junctional structures (about 1:9), a physical link between these channels is not likely to be involved in the modulation of Ca2+ release from the sarcoplasmic reticulum in cardiac muscle.

Animals↗
PubMed1991

Grafting of perfused adrenal medullary tissue into the caudate nucleus of patients with Parkinson's disease. Clinica Puerta de Hierro Neural Transplantation Group.

The authors report results obtained in 20 severely affected patients with Parkinson's disease (Grade IV or V) who received an autotransplant of perfused adrenal medullary tissue. This study seems to indicate that these autoimplants can improve the parkinsonian symptomatology and induce amelioration in the patients' performance of routine activities. All the symptoms analyzed showed improvement, although it differed in intensity and time of onset. Moreover, this improvement was accompanied by a reduction in the daily intake of L-dopa, with discontinuance of dopamine agonists and amantadine. A number of medical complications were encountered, including three deaths, probably related to performing abdominal surgery in seriously affected parkinsonian patients who were unable to tolerate the discontinuance of their medication. The transient psychiatric disorders observed appeared to be related to the postoperative dose of L-dopa and/or anticholinergic agents administered, and diminished or disappeared when the doses were reduced. The reasons for improvement, which was bilateral, remain unknown, although one cause may be the surgical trauma (minicaudotomy) together with the implantation of adrenal medullary tissue, which may promote the sprouting of surviving dopaminergic fibers. Moreover, in this series, perfusion of adrenal medulla increased the capacity for revascularization of the tissue and may have reduced the damaging effects of warm ischemia on the cells. This, together with the existence of fenestrated vessels, could hypothetically have served as an access point for drugs, and if the implanted cells were viable, they might have served to store and manufacture different factors and/or transmitters. These results as well as those of other groups justify the development of a controlled international clinical trial.

Adrenal Medulla↗
PubMed1991

Aspirin in transient ischemic attacks and minor stroke: a meta-analysis.

An overview analysis of seven randomized controlled trials testing the effectiveness of aspirin in the treatment of patients with transient ischemic attacks and minor strokes was performed. A total of 6409 patients from the seven trials was entered in the analysis; 2182 patients received only aspirin; 1598 patients received an aspirin-combination regimen with either sulfinpyrazone or dipyridamole; and 2629 subjects received a placebo. Aspirin alone produced an 18% decrease in all strokes and cardiovascular deaths. The pooling of studies examining aspirin-combination regimens and the larger grouping of studies of aspirin and aspirin-combination regimens led to more striking results. Indeed, significant risk reductions were observed for three of the four outcomes, namely, total deaths, total strokes, and total strokes and cardiovascular deaths, with odds ratios ranging from 0.59 to 0.78. Suggestive, albeit more modest, results were obtained when examining the impact of these regimens on total cardiovascular mortality. The same tendencies have also been observed in three previously published meta-analyses.

Adult↗
PubMed1991

A comparison of the inotropic effects of dopamine and epinine in human isolated cardiac preparations.

The positive inotropic effects of epinine and dopamine have been studied in isolated preparations obtained from human heart in the absence and in the presence of the selective beta adrenoceptors antagonists practolol and ICI 118,551. ED50 values of the two agonists were similar (about 3 x 10(-5) M). The inotropic efficacy of epinine was significantly higher than that of dopamine in adult ventricular and papillary muscles, it was similar to that of dopamine in juvenile myocardial preparations and in adult atria and pectinate muscles. The dopamine-evoked response was significantly more sensitive to practolol than epinine-evoked response, but it was less sensitive to ICI 118,551. pA2 values of practolol and ICI 118,551 were considerably different with epinine but not with dopamine as agonist. The results indicate that, compared to dopamine in isolated human heart preparations, epinine was more potent at beta-2 relative to beta-1 adrenoceptors.

Deoxyepinephrine↗
PubMed1990

Clinicopathological experience with pineocytomas: report of five surgically treated cases.

The clinicopathological experience associated with five cases of pineocytoma is presented. All patients were treated by surgical removal without postoperative radiotherapy. In three individuals, 2000 cGy was administered to the tumor as a presurgical diagnostic test, with no evidence of response. All cases demonstrated histological features of pineocytoma, according to the criteria of Borit et al., and of the so-called "pineocytoma with neuronal differentiation," according to the criteria of Rubinstein. The experience obtained from the present series reveals that these tumors can occur in the initial decades of life, that a cystic appearance and the presence of calcifications are distinctive features of their radiological evaluation, and that they have a good prognosis after surgical removal, even when the histological data indicate local invasion. The convenience of reserving the term "pineocytoma" for these tumors, and of including the so-called "pineocytomas without further differentiation" within the group of pineoblastomas, is suggested in order to achieve a practical clinicopathological assessment of parenchymatous pineal tumors.

Adolescent↗
PubMed1990

[Stimulation at home and psychological profile of mothers of children with or without weight loss during the first 15 days of life].

OBJECTIVES: To determine the possible difference of the microenvironment of a group of children who lost weight in their first 15 days of life. DESIGN: Longitudinal ecological study of growth and development of a total cohort of all children born during a calendar year. SETTING: Rural village of Central Mexico. PARTICIPANTS: A group of sixteen children, who fifteen days after birth and without apparent reason, showed a decrease in weight as compared with weight at birth, they were compared with a control group from the same population and matched, case by case, according to gestation age, height at the time of birth, and body weight. MEASUREMENT AND MAIN RESULTS: To assess the influence of microenvironmental factors two indicators were used. Recording and scoring of maternal behavior was done by adaptation to local conditions by Cravioto et al, of the Maternal Behavior Profile developed by Nancy Bayley. The instrument used for estimating home stimulation was the inventory developed by Caldwell design to sample certain aspects of the quantity and/quality of social, emotional, and cognitive stimulation available to a young child within his home. No significant differences were found in relation to Maternal Behavior Profile and Home Stimulation in the two groups studied (statistical differences, P greater than 0.05). CONCLUSION: Data from present study contribute to the claim that systematic stimulation in the home and an adequate interrelation mother-child are among the main elements necessary for the proper development of the child.

Female↗
PubMed1989

Inhibition by amlodipine of activity evoked in isolated human coronary arteries by endothelin, prostaglandin F2 alpha and depolarization.

Amlodipine, a dihydropyridine calcium antagonist has been examined on the rhythmic activity of isolated human coronary arteries. Amlodipine inhibited both the spontaneous rhythmic activity and the rhythmic activity evoked by prostaglandin F2 alpha and endothelin in isolated human coronary arteries. It also inhibited the contraction evoked by potassium depolarization. The action of amlodipine was characterized by slow onset and voltage dependency.

Amlodipine↗