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Biomedical subjects

J Roca

Publications and source records attributed to J Roca.

At least 307 records · Page 17Linked to original sources
PubMed1978

The dependence of T wave alternans on diastolic resting period duration.

The dependence of T-wave alternans on diastolic resting period duration as well as on regional differences in monophasic action potential duration was studied in the in situ dog heart. T-wave alternans was elicited when diastolic resting period shortened to values less than 41 +/- 6% of the cardiac cycle. This could be attained either by increasing the driving rate, or lengthening action potential duration by inducing hypocalcemia. During T-wave alternans, monophasic action potentials recorded from anterior and posterior left ventricular surface showed an alternation in duration; the degree in alternation in both regions differed and related to T-wave polarity.

Action Potentials↗
PubMed1976

Treatment of Kienböck's disease using a silicone rubber implant.

Ten patients with Kienböck's disease treated by resection and replacement with a silicone rubber implant through a volar approach were reviewed after follow-up ranging from twenty-four to thirty months. The results were good in seven and unsatisfactory in three: two patients had volar dislocation of the implant and one, median-nerve paresthesias of unexplained origin.

Adolescent↗
PubMedDate not supplied

Classification and quantification of abnormal sperm along the epididymal tract. Comparison between adult and aged hamsters.

The types and averages of abnormal sperm were studied in the epididymis of adult and aged golden hamsters. Abnormal spermatozoa represent 14.6-19.6% of the total of spermatozoa in adults, 31.7-42.1% in middled-aged hamsters, and 39.3-50% in advanced-aged hamsters. Twelve abnormal shapes were found, with the lack of an acrosome, the lack of a head, and the coiling of the tail, being the most frequent in the three age groups. An important increase in the number of coiled spermatozoa was found in the corpus and proximal cauda of the epididymis, but a decrease was observed in the distal cauda. Our data suggest that the epididymis produces secondary defects in spermatozoa running from the proximal caput to the middle zone of the duct, but that many of these spermatozoa are eliminated in the distal cauda. Such a result is mainly found in aged animals, in which a higher percentage of abnormal sperm from secondary origin is found with respect to adults.

Aging↗
PubMedDate not supplied

Occupational asthma in the community: risk factors in a western Mediterranean population.

Risk factors and prevalence of occupational asthma in the general population were examined in a cross-sectional community study conducted in north Barcelona. A self-administered questionnaire that contained questions about bronchial asthma and occupation was mailed to a random sample of 4000 adults who lived in north Barcelona; the response rate was 31.0%. Investigators made phone calls to nonresponders to determine response bias. Risk factors for occupational asthma were assessed with logistic regression. Investigators, who sought a definite diagnosis of occupational asthma, offered a chest examination to all subjects who reported asthma in life and who experienced clinically relevant occupational exposures. The examination included skin tests to common allergens, forced spirometry with reversibility test, and peak expiratory flow rate at and away from work. Cumulative prevalences obtained from responders were good estimates for the general population: asthma in life, 9.0%; clinically relevant occupational exposure, 28.9%; and respiratory symptoms at work, 18.3%. Adjustments were made for age, sex, and smoking habits, and relevant exposure caused an increase in asthma risk (odds ratio [OR] = 1.9; 95% confidence interval [95% CI] = 1.1, 3.2); however, when investigators introduced specific occupations in the model as independent variables, only occupational exposure to leather (OR = 12.8 [95% CI = 4.4, 37.4]), animals (OR = 10.3 [95% CI = 1.6, 65.2]), dyes (OR = 5.6 [95% CI = 2.1, 15.3]), and flour (OR = 4.6 [CI = 1.3, 15.7]) persisted as significant risk factors. A 1.7/1000 minimum prevalence of occupational asthma for the north Barcelona population was estimated from chest examination results. Occupational risk for asthma appeared to be associated with exposure to leather, animals, dyes, or flour in the north Barcelona area.

Adult↗
PubMedDate not supplied

Prevalence of dementia in a semi-rural population of Catalunya, Spain.

This study was to investigate the prevalence of dementia in an aging population. A two-phase model was used to obtain information on the socio-demographic, medical and cognitive status of subjects over 65 years of age (n = 516), resident on December 31, 1990, within the general population (n = 3,457) of La Selva del Camp. A diagnostic protocol, following the criteria of DSM-III, was designed for application to all subjects. We diagnosed 64 subjects with dementia, which represented a prevalence of 14.9% of which 3.2% was classified as severe, 4.5% as moderate and 7.3% as slight. The prevalence by age and sex showed a large increase with age and a higher prevalence in females, although the latter was not statistically significant.

Age Factors↗
PubMedDate not supplied

Preoperative platelet count and postoperative blood loss in patients undergoing hip surgery: an inverse correlation.

In a previous study we tried to assess the clinical usefulness of platelet count (PlC) to confirm whether postoperative pulmonary embolism could be suspected early. Unexpectedly, the 19 patients who subsequently developed pulmonary embolism had significantly lower mean PlC levels even before surgery. In an attempt to discover whether the preoperative PlC levels were associated with a different incidence of postoperative blood loss, we decided to retrospectively study the relationship between preoperative PlC levels and the consequences of blood loss. There were 459 consecutive patients undergoing hip surgery. After excluding 5 patients who died during the first 3 postoperative days, and 16 patients who bled from a definitive anatomic site, there were 438 patients. Blood loss was considered to be excessive when two or more of the following conditions were present: (1) total transfusion requirements exceeding 1,000 ml whole blood or 2 units of packed red cells; (2) a drop in hemoglobin level of 5 g/dl or more, and (3) a hemoglobin level below 8 g/dl at any moment during the first 8 postoperative days. Blood loss was considered to be excessive in 91 patients. Preoperative PlC levels were significantly lower in these patients as compared to patients without the condition (204 +/- 52 vs. 236 +/- 79 x 10(9) liter-1; p = 0.0002). When patients were classified according to the quartiles of preoperative PlC, the odds ratio of developing excessive blood loss was 0.69 (95% CI: 0.38-1.26) in patients in the second quartile; 0.57 (95% CI: 0.30-1.06) in the third quartile, and 0.27 (95% CI: 0.13-0.57) in patients in the highest quartile. After adjusting for age, sex, type of surgery and type of prophylaxis, the preoperative PlC levels maintained a statistically significant inverse correlation with postoperative blood loss.

Aged↗
PubMedDate not supplied

[Clinical assessment of a new anesthetic system: the Temel Supra (II)].

OBJECTIVES: To assess the clinical performance of a new anesthetic system developed to provide novel advantages in ventilating the anesthetized patient. PATIENTS AND METHOD: The clinical performance of the Temel Supra was evaluated in 100 adult patients who were anesthetized and ventilated using the device. RESULTS: The patients were adequately oxygenated and ventilated; no adverse events were observed. An open circuit, low flow, or closed circuit could be chosen freely. Ventilation was fully monitored: among the variables measured were rebreathed volume; leaks while the patient was connected; consumption of oxygen, nitrous oxide and anesthetic agents; and cardiac output (noninvasively). CONCLUSIONS: Ventilation and gas exchange were satisfactory in all cases even though some patients developed considerable respiratory impedance. The monitoring of oxygen and other gases consumed and of carbon dioxide produced provided very valuable information about metabolism and pharmacokinetics. The noninvasive monitoring of cardiac output seems to us to be a useful feature for aiding hemodynamic control. The independence of the open and closed circuits means that expired gases do not pass through the canister when the open circuit is used, resulting in savings on soda lime for drying. During pressure-control ventilation, the system maintains a plateau to guarantee better distribution of inspired gases. Other important features are warnings, constant monitoring of leaks, the 100% efficacy of the circuit, and the low internal volume.

Adult↗
PubMedDate not supplied

[Results of valvuloplasties with balloon catheter in children. Follow-up using pulsed Doppler. Experience with our first cases].

Our series includes the first 19 consecutive patients with pulmonary valvar stenosis who underwent balloon valvuloplasty in our hospital. All of them have been evaluated by an echo-Doppler study at different follow-up times, and in 10 patients the study was also performed prior to the dilatation. The ages ranged between 0.4 and 10 years (mean 3.5 years; standard deviation [SD] 2.53 years). The prevalvuloplasty degree of pulmonic stenosis found at catheterization was quantified as severe in 8 cases (42.11%) with a right ventricular systolic pressure (RVSP) in excess of 90 mmHg, and moderate in 11 cases (57.89%) with an RVSP from 70 to 90 mmHg. Transvalvular gradients were registered between 38 and 110 mmHg (m: 69 mmHg and SD: 15 mmHg). According to catheterization data obtained at the time of valvuloplasty, the procedure was considered ineffective in 2 cases (10.52%), scarcely effective in four (21.05%), and successful in the remaining 13 cases (68.42%). Doppler follow-up was carried out between 1.6 and 31.9 months after valvuloplasty (mean 12.9 months and SD: 10 months). Residual stenoses were estimated by Doppler as mild in 13 cases (68.42%), moderate in four (21.05%) and severe in two (10.52%). Mild pulmonary regurgitation was detected in 10 patients (52%). The 13 patients with a satisfactory result had slight residual gradients at the valvular level that had not been modified with the course of time. Of the 4 cases with a poorly effective dilatation the gradients noted by Doppler increased in three of them, being valvular in all but one in whom the obstruction was catalogued as infundibular.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheterization↗
PubMedDate not supplied

Gas exchange response to naloxone in chronic obstructive pulmonary disease with hypercapnic respiratory failure.

It has been hypothesized that naloxone may alter the ventilation-perfusion relationship in patients with chronic obstructive pulmonary disease (COPD) with associated respiratory failure, through the release of hypoxic pulmonary vasoconstriction. To investigate the effects of naloxone on gas exchange, seven clinically stable patients with severe COPD (type B) (forced expiratory volume in one second/forced vital capacity (FEV1/FVC) 38.3 +/- 4.0%) with hypoxaemia and hypercapnia (PaO2 7.6 +/- 0.4 kPa; PaCO2 6.4 +/- 0.3; pH 7.37 +/- 0.02), aged 59.0 +/- 4.6 yr, were studied. Breathing patterns, haemodynamic and conventional and inert gas exchange measurements were made while breathing room air before, during and 60 min after i.v. naloxone infusion. Naloxone and catecholamine plasma levels were also determined. In three subjects (protocol A), measurements were made using increasing concentrations of naloxone (cumulative dose: 54 mg), while the remaining four patients were studied (protocol B) at a fixed concentration of naloxone (cumulative dose: 38 mg). Despite high levels of naloxone (up to 150 ng.ml-1), no significant differences from baseline were observed in any of the measurements, during or after infusion. It is concluded that i.v. naloxone given as described has no effects on pulmonary gas exchange in clinically stable COPD patients with chronic respiratory failure.

Breath Tests↗