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Biomedical subjects

J Alonso

Publications and source records attributed to J Alonso.

At least 217 records · Page 12Linked to original sources
PubMed1993

Development and characterization of an ergometer to study the bioenergetics of the human quadriceps muscle by 31P NMR spectroscopy inside a standard MR scanner.

A description is given of an ergometer made of nonmagnetic materials which fits into a standard whole body MR magnet. T2-weighted images show that exercise is highly specific for quadriceps muscles. The ergometer permits the noninvasive study of T2-related changes in the proton images of the leg as well as changes occurring in muscle bioenergetics during exercise and recovery.

Equipment Design↗
PubMed1993

A versatile perifusion system for the NMR spectroscopy of bovine retina. Assignment of resonances and effect of ischemia.

A perifusion system has been designed for metabolic nuclear magnetic resonance (NMR) spectroscopy studies of the bovine retina. This system, which allows the use of unmodified commercial probes for multinuclear studies, is shown here to maintain the perifused retina in a metabolic steady state at 25 degrees C, as deduced from its 31P and 1H NMR spectra. The 31P NMR ex vivo spectrum of the retina has been characterized, and its major resonances have been assigned in tissue extracts. We have found that excised retinal tissue subjected to 2 hr of ischemia is capable, upon perifusion with oxygenated medium, of recovering its resting spectral pattern. Thus, this system offers a versatile model for studies of physiological events related with ischemia in a neural tissue, without associated systemic effects.

Animals↗
PubMed1993

Open, randomized therapeutic trial of six antimicrobial regimens in the treatment of human brucellosis.

This report describes the results of six antimicrobial regimens used for the treatment of brucellosis in an open, randomized study performed over two periods (1980-1983 and 1984-1987). In the first period, rifampicin and doxycycline were used for 4 weeks, trimethoprim-sulfamethoxazole for 6 months, and doxycycline for 6 weeks. During the second period, we used streptomycin for 2 or 3 weeks together with doxycycline for 6 weeks and rifampicin with doxycycline for 6 weeks. Comparison of the results showed the following: (1) no statistically significant findings were revealed when the different regimens were compared and (2) the regimens containing streptomycin yielded statistically more favorable results than those consisting of rifampicin and monotherapy when the patients treated with rifampicin were compared with those taking streptomycin and those receiving single-agent therapy. No significant differences were observed between monotherapeutic regimens and those including rifampicin.

Adolescent↗
PubMed1993

[Stress].

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Adaptation, Physiological↗
PubMed1993

31P-MRS of quadriceps reveals quantitative differences between sprinters and long-distance runners.

Phosphorus-31 nuclear magnetic resonance spectroscopy (31P-MRS) has been used to characterize the spectral pattern of quadriceps muscle at rest for sedentaries (N = 10), sprinters (N = 12), and long-distance runners (N = 10). Intracellular pH (pHi), phosphocreatine (PCr), inorganic phosphate (Pi), phosphodiesters (PDE), adenosine triphosphate (ATP) and total phosphate (Pt), defined as the sum of the areas of PCr, PDE, Pi, and 3 times the beta-ATP resonances, were obtained from all spectra. The pHi and ATP/Pt ratio were the same in the three groups of people studied. The PCr/Pi and PCr/Pt ratios were significantly lower and the Pi/Pt ratio was significantly higher for long-distance runners than for sprinters and sedentaries, while the PDE/Pt ratio was significantly lower for sprinters than for sedentaries and long-distance runners. Furthermore, the PCr concentration for sprinters and sedentaries was significantly higher and the Pi was significantly lower than for long-distance runners. The results obtained in this study can be explained by the accepted differences in fiber type composition between sprint and endurance athletes. We suggest that 31P-MRS at rest could be used to monitor noninvasively the individual adaptive response to training in the metabolic characteristics of the athlete muscle fiber.

Adaptation, Physiological↗
PubMed1992

International Quality of Life Assessment (IQOLA) Project.

The International Quality of Life Assessment (IQOLA) Project is a 4-year project to translate and adapt the widely used MOS SF-36 Health Survey Questionnaire in up to 15 countries and validate, norm, and document the new translations as required for their use in international studies of health outcomes. In addition to the eight-scale SF-36 health profile, the project will also validate psychometrically based physical and mental health summary scores, as well as health utility indexes incorporating SF-36 scales for use in cost-utility studies.

Europe↗
PubMed1992

Clinical gain from improved beam delivery systems.

The feasibility of dynamic conformal heavy charged particle radiotherapy has been investigated at UCLBL, and shows high promise of: 1. an improved therapeutic ratio and 2. reduction in the number of treatment portals required for efficient treatment delivery. Assessment of dose to tumor and critical structures for several anatomical sites have been carried out using a normal tissue complication algorithm developed at LBL. For high-LET charged particle treatment delivery, dynamic conformal therapy using a raster scanned beam with variable modulation and multileaf collimator appears to be the optimal technique for treatment delivery.

Energy Transfer↗
PubMed1992

Covalent binding of urease on ammonium-selective potentiometric membranes.

As part of the development of disposable urea bioselective probes, the covalent binding of urease on ammonium-selective potentiometric membranes has been assessed. Nonactin/bis(1-butylpentyl)adipate/poly(vinylchloride) (PVC) membranes, directly applied to an internal solid contact (conductive epoxy-graphite composite), has been used as a support for covalent immobilization of urease. Two types of all-solid-state construction process have been assayed: thin layers of cellulose acetate (CA) were coated on the PVC ammonium-selective membranes (type 1) and blends of PVC and CA at various ratios were used as ammonium-selective membrane matrices (type 2). Urease was covalently attached to CA via aldehyde groups. These groups were created on the polysaccharide with sodium periodate to which the enzyme was immobilized through a spacer (hexamethylenediamine). The viability of both types of probe for the determination of ammonium ions was assessed after each step of the activation process. Results indicated that type 2 potentiometric probes are altered after the treatment with sodium periodate. Good results were obtained with type 1 probes. Their dynamic concentration range of response to urea was from 2 x 10(-5) to 0.01 M with a sensibility of 50 mV/decade.

Ammonia↗
PubMed1992

Laterality, alternation, and perseveration relationships on the T-maze test.

The T-maze test has been used to study several entirely different issues: spontaneous alternation behavior (SAB), perseveration behavior (PB), and behavioral lateralization. Despite the fact that in this test the behavior studied is always the same one (i.e., side choice), the possible relationships among SAB, PB, and lateralization have not been previously evaluated. The present study investigated the relationships among these functions. The results demonstrated that (a) shock increases PB and lateralization but decreases SAB, (b) practice increases lateralization and decreases SAB but does not modify PB, and (c) there are sex differences for alternation and SAB. Because these functions are expressed by the same behavioral pattern, they must be quantified simultaneously to avoid mistaken conclusions when the T-maze test is used.

Animals↗
PubMed1992

Effect of training on the calf muscle energy metabolism. A 31P-NMR study on four elite downhill skiers challenged with a standardized exercise protocol.

This study evaluates the effects of a 6 months' training period on the bioenergetics of the calf muscle of elite athletes by means of phosphorus-31 Nuclear Magnetic Resonance Spectroscopy (31P-NMR). Four downhill skiers, belonging to the Spanish National Team, performed a standardized exercise protocol using their right leg inside a wide-bore 2.35 Tesla magnet. The inorganic phosphate/phosphocreatine (Pi/PC) ratio and intracellular pH (pHi) were measured at steady-state during an exercise protocol composed of 5 work levels between 20% and 80% of the maximum voluntary contraction (MVC), before and after the training period. The measured values, which were markedly scattered at the beginning, regrouped after training. This was caused by a shift towards lower Pi/PC ratios and by a lower pHi acidification in three of the four subjects. This result suggests that 31P-NMR is a good tool to evaluate changes in the muscle aerobic capacity of athletes induced by training.

Adenosine Diphosphate↗
PubMed1992

Epidemiology of prostatic disorders in the city of Barcelona.

Although disorders of the prostate are among the most prevalent problems in elderly males, little is known about their epidemiological characteristics. The 1986 Barcelona Health Interview Survey (BHIS), a cross-sectional study of a random sample of the noninstitutionalized population of the city, was used to estimate the prevalence of prostatic disorders (PD) and to analyse sociodemographic characteristics, self-perceived health, and use of health services among males reporting PD. Ninety-eight out of 1218 males over 45 years old (8%) reported having PD, the prevalence increasing substantially with age. A pattern of increasing prevalence with decreasing occupational class was found. As compared to subjects not reporting PD, individuals reporting PD reported slightly more restricted activity days (prevalence odds ratio [POR] = 1.28; 95% confidence interval [CI]: 0.52-2.80), more chronic disorders (POR = 4.75; 95% CI: 2.04-13.53), and worse self-perceived health (POR = 1.55; 95% CI: 0.92-2.58). Medical visits and hospitalizations were also higher in the prostatic group (P < 0.05). Men reporting PD appear to constitute a subgroup with increased morbidity and health services use.

Age Factors↗
PubMed1992

Measurement of general health status of non-oxygen-dependent chronic obstructive pulmonary disease patients.

Chronic obstructive pulmonary disease is a prevalent condition causing a high level of disability, and it is one of the leading causes of death. To assess the general health status of moderate to severe Chronic obstructive pulmonary disease patients, we studied 76 male patients attending an outpatient hospital clinic who were not dependent on oxygen and who did not present bronchial obstruction reversibility. We assessed clinical status (dyspnea, six-minute walking distance) and functional respiratory impairment (spirometry, and blood gas analysis) of the patients and also asked them to respond to the Spanish version of the Nottingham Health Profile, a multi-dimensional generic health status measure. Patients scored especially higher than the general population (denoting more level of distress) in energy, physical mobility and sleep Nottingham Health Profile dimensions. The former two dimensions scores had a high correlation with dyspnea (respectively Spearman Rs = 0.60, and Rs = 0.64; P less than 0.01). High levels of sleep disturbances were found for patients reporting low or very low dyspnea level. Health status measurement (Nottingham Health Profile dimension scores) and functional respiratory impairment were not correlated. Results underscore the importance of measuring symptoms carefully when assessing these patients, whose health status is substantially affected by the Chronic obstructive pulmonary disease. They also suggest that it is relevant to assess sleep disturbances in these patients.

Activities of Daily Living↗
PubMed1992

Favorable effects of hyperosmotic reperfusion on myocardial edema and infarct size.

Myocardial water content and infarct size were studied in 39 pigs randomly assigned to a nonintervention group, a group with an intracoronary infusion of a control solution, and a group with a hyperosmotic infusion to 450 mosM by the addition of D-mannitol. The intracoronary solutions were selectively infused into the left anterior descending coronary artery just distal to the occlusion site starting 48 min after occlusion. Reperfusion was performed 3 min later and the infusion rate progressively tapered off over the following 33 min. Multiple myocardial fragments were then obtained in nine pigs, from endocardial, mesocardial, and epicardial regions of the ischemic and control myocardium. Water content measured after 48 h of dessication was significantly greater in the reperfused [530 +/- 7 ml/100 (mean +/- SE) g dry wt] compared with control myocardium (374 +/- 3; P less than 0.0001) and similar in reperfused control and isotonic infusion groups (556 +/- 7 and 543 +/- 8 ml/100 g dry wt); it was 491 +/- 11 with intracoronary D-mannitol infusion, representing 35% less increase (P less than 0.001). In the 30 remaining pigs, area at risk and infarct size were measured 24 h later by in vivo fluorescein and in vitro triphenyltetrazolium chloride. Infarct size was similar in control and in the isotonic reperfused hearts, 6.80 +/- 1.05 and 6.22 +/- 0.76% of ventricular weight, and smaller with D-mannitol, 4.46 +/- 0.46 (P less than 0.05). The ratio of infarct size to area at risk was also smaller [0.415 +/- 0.029 vs. 0.543 +/- 0.052 and 0.547 +/- 0.045 (P less than 0.02)].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Selective inhibition of the contractile apparatus. A new approach to modification of infarct size, infarct composition, and infarct geometry during coronary artery occlusion and reperfusion.

BACKGROUND: Myocardial reperfusion is associated with calcium overload and cell contracture, mechanisms that may precipitate cell death. In this study, we tested the hypothesis that in vivo inhibition of this contracture could lead to cell preservation in an open-chest large animal model. METHODS AND RESULTS: Regional myocardium function was measured during a selective intracoronary infusion of 2,3-butanedione monoxime (BDM), a specific inhibitor of actin-myosin coupling, in the control state (10 pigs) and in a protocol of a 51-minute coronary occlusion followed by reperfusion (40 pigs). The effects on coronary artery blood flow in the basal state were also studied (seven pigs). Intramyocardial distribution of the infusate during coronary occlusion, myocardial water content after 30 minutes of reperfusion and area at risk, infarct size, type of histological necrosis, and infarct geometry after 24 hours of reperfusion were assessed. Methods used included electromagnetic flowmeter, radiolabeled microspheres, subendocardial sonomicrometers, fluorescein, triphenyl tetrazolium chloride and Masson's trichrome staining, and computer quantification of infarct edges. In the absence of ischemia, BDM infusion inhibited regional shortening in a dose-dependent manner up to full systolic bulging while producing marked regional increase in coronary blood flow. During early reperfusion, BDM reduced end-diastolic length 76% more than the control infusion (p less than 0.05) and increased systolic bulging by 420% compared with no change in control animals. The ratio of infarct size/area at risk was reduced by 31% with BDM (p less than 0.05), with striking modifications of infarct histology and infarct geometry; specifically, the extent of contraction band necrosis was reduced by 63% from 105.5 +/- 18.2 to 39.2 +/- 13.6 mm2 (p less than 0.02), and more patches of necrosis (6.5 +/- 2.1 versus 1.6 +/- 0.4, p less than 0.05) and higher contour (7.7 +/- 1.2 versus 5.03 +/- 0.2, p less than 0.05) and fractal (12.1 +/- 1.3 versus 7.8 +/- 0.2, p less than 0.05) indexes were found. CONCLUSIONS: Selective intracoronary infusion of BDM at doses inhibiting regional wall motion decreased infarct size after reperfusion. The effects of BDM on regional function, the reduction in contraction band necrosis at histology, and the peculiar configuration of these infarcts all suggest that inhibition of contracture can interfere with cell-to-cell progression of myocardial necrosis, supporting a role for contracture in reperfusion-induced cell death.

Actins↗
PubMed1992

Incidence of arterial oxygen desaturation in cardiac patients premedicated with intramuscular scopolamine and morphine.

The effect of a standard preoperative medication combination, morphine and scopolamine, on arterial oxyhemoglobin saturation was measured continuously in 29 patients scheduled for elective coronary artery bypass grafting procedures. On the morning of operation, both before and after administration of preoperative medication, each patient was monitored continuously with a pulse oximeter (SpO2). Patients received 0.05 to 0.11 mg/kg of morphine (mean = 6.0 +/- 2.1 mg) intramuscularly (IM) and 0.2 to 0.4 mg of scopolamine (mean = 0.30 +/- 0.07 mg) IM. The mean arterial blood oxyhemoglobin saturation decreased from 92.0 +/- 1.8% before preoperative medication to 89.0 +/- 3.8% (P greater than .001) after preoperative medication. Forty-five percent of the patients had SpO2 less than 90% for at least 2 minutes, and 21% below 85%. In conclusion, significant arterial oxyhemoglobin desaturation occurred in this group of cardiac surgical patients after preoperative medication with morphine and scopolamine. Prophylactic administration of oxygen with preoperative medication might reduce the incidence of hypoxemia in this group of patients at risk for myocardial ischemia.

Aged↗