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Biomedical subjects

P Rivas

Publications and source records attributed to P Rivas.

At least 19 recordsLinked to original sources
PubMed2003

[Laryngeal chondro-radionecrosis].

Laryngeal chondroradionecrosis is a complication following radiotherapy for laryngeal tumours that may appear many years after the treatment. We present the case of a 78 year old man, that come to the Accident and Emergency department with a prelaryngeal mass and hemoptysis. He had been treated 17 years before with radiotherapy for a vocal cond carcinoma. Posteriorly the lesion did a cutaneous fistula with complete laryngeal exposition and torpid evolution. Post-radiotherapy necrosis in the larynx is a serious complication though not a common one. A tumour recurrence needs to be excluded and even in this case a total laryngectomy is mandatory as it will end in total loss of laryngeal function.

Aged↗
PubMed2003

Psychosocial profile in favor of organ donation.

INTRODUCTION: The lack of organ donation continues to be a major limiting factor in transplantation. Our aims are: (1) to define the psychosocial profile against organ donation, and (2) to determine the impact of a law on the procurement and transplantation of organs based on "presumed consent" in the population. MATERIALS AND METHODS: The population in this study (n = 2000) was randomly selected and stratified according to sex, age, and geographic localization. The attitude toward organ donation and transplantation was evaluated according to a questionnaire that probed psychosocial aspects of donation. Statistical comparisons were performed using the chi2 and logistic regression tests. RESULTS: The population attitude toward organ donation was favorable in 63% of subjects, unfavorable in 31%, and 6% did not respond. With regard to the law based on "presumed consent," only 24% of the population agreed with the law; 53% thought it was an abuse of authority. The population subgroup with a negative attitude to the law was characterized by: age over 40 years, low educational level, no previous experience with organ donation or transplant, no experience in prosocial activities, a refusal to accept cadaver manipulation or mutilation, and lack of knowledge of the brain-death concept. CONCLUSIONS: The psychosocial profile against donation is a person above 40 years with a low level of education who has never performed prosocial activities, did not have previous experience with organ donation or transplantation, displays no knowledge of the brain-death concept, and rejects cadaver manipulation. For these people a law based on "presumed consent" is considered an abuse of authority.

Adolescent↗
PubMed1999

[The truthfulness of the answers of children, adolescents and young people to surveys on tobacco consumption conducted in schools].

BACKGROUND: The prevalence of tobacco consumption in scholars has been determined by self-governed inquiries, methodology that presents limitations of reliability and validity. This obstacle has been endeavoured to overcome through methodological inspections such as the test-retest valuation. On the contrary, the available analytical methods (i.e., determination of cotinine in urine or determination of carbon monoxide [CO] in exhaled air) have not been used up to now in this type of studies. Their use together with the inquiries could complement the results of the questionnaires and verify their reliability. POPULATION AND METHODS: 814 scholars took part in the survey, being valid the results of 809, 385 male students and 424 female students, 13 to 24 years old (mean 15.90, SD 1.73) from an urban high school and another in the rural area. The survey included a survey and the measurement of CO levels in exhaled air in the same scholar centre. RESULTS: 257 scholars stated that they had never tried tobacco and in 15 of them (5.8%) levels of CO were equal or higher than 10 ppm (14.26, SD 4.35 ppm). 589 students stated that were not regular smokers; in 46 of them (7.8%) levels of CO were superior to 10 ppm (13.87, SD 4.68). The morning when the survey was held 629 students assured that they had not smoked: in 52 of them (8.3%) levels of CO higher than 10 ppm were observed. The mean level of CO observed in these students was 13.5 (SD 4.4) ppm. In our survey, the measurement of CO in exhaled air allowed us to show percentage between 5.8 and 8.3% of students whose answers to the different questions were not reliable. CONCLUSIONS: The reliability of the results, observed through the carrying out of surveys, can be determined with the use of analytical methods that, owe to their simplicity, can be used massively. We have not found any relation between the shortage of reliability and the variants studied (age, sex or habitat), which reaffirms the difficulty in identifying variants that can determine those "deceives" and demands for its identification the need of practicing analytical determinations.

Adolescent↗
PubMed1999

Effects of some beta-carboline alkaloids on intact Trypanosoma cruzi epimastigotes.

Several beta-carboline (9H-pyrido-[3,4-b]-indole) alkaloids were evaluated for in vitro trypanosomicidal activity against Trypanosoma cruzi epimastigotes belonging to two different strains (Tulahuén and LQ) showing different sensitivity to nifurtimox. Important differences were observed in the susceptibility of the parasites to these natural substances, with the relatively nifurtimox-resistant LQ strain showing greater sensitivity to the beta-carbolines. Respiratory chain inhibition appears to be a possible determinant of the trypanosomicidal activity of these compounds.

Animals↗
PubMed1998

[Sex differences in experimentation and tobacco consumption by children, adolescents and young adults].

Studies carried out in the past ten years have found the prevalence or smoking among children and adolescents to be high, with the greatest increase observed for girls and young women, indicating increasing gender-related differences. The aim of our study was to determine the prevalences and differences among children and adolescents of both sexes with regard to experimentation and use of tobacco products and to determine any possible influence related to urban or rural environment. Eight hundred fourteen students participated, with 809 providing valid data for study: 385 males and 424 females ranging in age from 13 to 24 years old (15.90 +/- 1.73 years). The subjects studied in either an urban or a rural school. Data was collected on campus by questionnaire and carbon monoxide in expired air was measured. Smoking had been tried by 68.2%: 241 males (62.5%) and 31 females (73.3%) (p < 0.001). Habitual smoking was reported by 27.2%: 78 males (20.2%) and 142 females (33.4%) (p < 0.001). Mean ages of experimenters (16.18 +/- 1.78 years) and smokers (16.55 +/- 1.85 years) were higher than the mean age of non-experimenters (15.29 +/- 1.43) (p < 0.001). Habitual smokers consumed a mean 2.71 +/- 1.68 cigarettes/day and consumption was similar for both sexes. CO in expired air was 12.61 +/- 6.39 ppm in these smokers, significantly higher (p < 0.001) than that found in experimenters and non smokers (p 0.001). One hundred eighty students (22.2%), 119 females and 61 males (p < 0.001), reported having smoked on the morning of the study. In total, 81.8% of the students who described themselves as smokers had smoked that morning: 78.2% of the males and 83.9% of the females. CO in this group was 13.95 +/- 1.69 ppm, significantly higher than that found for the other groups (non smokers or experimenters). We found no significant differences between number of cigarettes/day smoked by students who reported being habitual smokers and the number consumed the morning of data collection by students who had smoked the day of the study. Changes can be observed in patterns of tobacco use among children and young people. We found that nearly all aspects related to experimentation and consumption of tobacco are significantly higher in females.

Adolescent↗
PubMed1998

[Usefulness of CO measurement in expired air in the study of tobacco consumption by youths and adolescents].

The objective of our work was to know the relationship between carbon monoxide (CO) levels in expired air and smoking habits among school youths and the relationships that can be established between CO level and some peculiar attitudes regarding consume by youths, such as the number of cigarettes, inhaling technique and time elapsed since the last cigarette was smoked. The study, of cross-sectional design, was performed in two high school centres and a total of 777 students who answered a questionnaire and had an expired air CO sample in their own schoolroom tested were enrolled. CO determination in the schoolroom was a simple and attainable technique for the pupils, as only 32 cases (4.1%) had to be excluded due to poor collaboration or poor technique. The mean (mean and SD) CO level in the control group (n = 247), made up by non-smokers nor tobacco tasters was 4.75 (2.46) ppm, statistically lower than among smokers (p < 0.001), but with no differences compared with non smokers (n = 563), who had a CO level of 5.23 (3.4) ppm. This figure was also lower (p < 0.001) than that obtained in the smokers (12.6 [6.3] ppm), made up of 214 pupils, with a mean consume of 2.7 (1.69) cigarettes/day. Among smokers the mean abstinence time since the last cigarette was smoked was 26 (44) minutes and 54% of them admitted to have smoked in the last 10 minutes. CO in expired air correlated significantly with the number of smoked cigarettes (r = 0.58; p < 0.001). Likewise, it correlated significantly with abstinence minutes (r = -0.38; p < 0.001). The time required for CO level to decrease below 10 ppm was 140 minutes in four cases and 120 minutes in 33 cases.

Adolescent↗
PubMed1997

Comparative effectiveness and safety of cefdinir and amoxicillin-clavulanate in treatment of acute community-acquired bacterial sinusitis. Cefdinir Sinusitis Study Group.

Cefdinir is an extended-spectrum oral cephalosporin that is active against pathogens commonly seen in acute community-acquired bacterial sinusitis (ACABS), including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Two randomized, investigator-blind, multicenter trials (one in the United States and one in Europe) compared two dosage regimens of cefdinir (600 mg once a day for 10 days and 300 mg twice a day for 10 days) to amoxicillin-clavulanate (A-C) (500 mg three times a day for 10 days) for adult and adolescent patients with ACABS. Twelve hundred twenty-nine patients entered the U.S. study, 698 with antral puncture; 569 patients entered the European study, all with antral puncture. Clinical response (cure or improvement) was determined 7 to 14 days and 3 to 5 weeks posttherapy. Microbiologic eradication rates were determined 10 to 30 days posttherapy in a subset of patients who underwent pre- and posttherapy sinus aspirate culture. Rates of adverse events and treatment discontinuations due to adverse events were examined. Cefdinir, given once or twice daily, was as effective clinically (approximately 90% cure rate) as amoxicillin-clavulanate given three times daily in the treatment of ACABS. Microbiologic eradication rates were also similar in the three groups. The major side effect was mild diarrhea, occurring in approximately 20% of each group. Cefdinir caused fewer adverse events requiring treatment discontinuation.

Adolescent↗
PubMed1991

[Ludwig's angina, its evolution and treatment].

An anaerobic neck infection located in the submandibular layer is described in this paper. We report a case of satisfactory evolution and make a bibliographic review of this problem. All the AA. agree that the key to successful management of such infections is early diagnosis, prompt surgery and associated antibiotic therapy.

Adult↗
PubMedDate not supplied

Morphometric study of fetal brain transplants in the insular cortex and NGF effects on neuronal and glial development.

Homotopic grafts supplemented with nerve growth factor (NGF) speed the recovery from learning deficits observed following electrolytic lesions of the insular cortex in rats. NGF also reduces the time in which the activity of choline acetyltransferase (ChAT) is first detected inside the graft by histochemical techniques. It is not known whether this behavioral and biochemical recovery correlates with an advanced maturation of the cellular elements within the graft, presumably induced by NGF. To investigate the degree of maturation of neurons, glial cells and blood vessels in NGF-supplemented grafts, adult rats were lesioned electrolytically in the insular cortex, and homotopic embryonic grafts (E16) with or without NGF supplementation were transplanted into the lesion. Fifteen days post grafting, the rats were perfused and the brains stained using silver impregnation techniques. Our results showed that neuronal maturation, as evaluated through several morphometric parameters, was advanced in NGF-supplemented grafts when compared with other experimental groups. Furthermore, grafts supplemented with NGF also showed significant increases in the number of neurons, oligodendrocytes, astrocytes and blood vessels. These observations indicated that the addition of NGF to insular cortex grafts promoted the maturation of neuronal and glial elements within the graft. They also support the possibility that the advanced morphological maturation of insular cortex grafts supplemented with NGF underlies the accelerated functional and biochemical recovery of animals with lesions of the insular cortex.

Animals↗