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Biomedical subjects

M A Barros

Publications and source records attributed to M A Barros.

At least 19 recordsLinked to original sources
PubMed2003

Enhancement of carotid chemoreceptor reflex and cardiac chemosensitive reflex in the acute phase of myocardial infarction of the anesthetized rabbit.

In the acute phase of cardiac ischemia there is an imbalance of the autonomic outflow with a depression of the baroreceptor reflex. Carotid chemoreceptor stimulation evokes an increase on arterial blood pressure and bradycardia in the anesthetized and paralyzed animal. The activation of cardiac chemosensitive fibers elicit the Bezold-Jarisch reflex comprising a decrease of arterial blood pressure and bradycardia. In the present study, we studied the modifications of the carotid chemoreceptor reflex and the Bezold-Jarisch reflex elicited during the acute phase of myocardial infarction (MI) in the anesthetized and paralyzed rabbit. Rabbits were anesthetized with pentobarbitone, paralyzed and artificially ventilated. The carotid sinus region was exposed and a cannula was inserted retrogradely through the external carotid artery into the carotid bifurcation; the carotid body was stimulated by a lobeline injection. A catheter was advanced, via the right carotid artery, to the origin of the aorta and the Bezold-Jarisch reflex was evoked by an injection of ATP. The baroreflex was provoked by an increase in after-load or by clamping the common carotid artery. Heart ischemia was provoked by ligation of the descending coronary artery. Arterial blood pressure, carotid artery pressure, heart rate and electrocardiogram were monitored. Stimulation of cardiovascular and cardiac receptors was performed before and after coronary ligation. Results show an overall increase in the cardiovascular reflex responses elicited by stimulation of chemically activated receptors and an overall decrease of the baroreceptor responses after MI. In conclusion, these data show the existence of an enhancement of the reflex cardiovascular responses to carotid chemoreceptor and cardiac chemosensitive receptors stimulation and confirmed the depression of baroreceptor reflexes following heart ischemia that could account for the imbalance of the autonomic output observed in the acute phase of myocardial infarction.

Adenosine Triphosphate↗
PubMed2000

Efficacy of prophylactic droperidol, ondansetron or both in the prevention of postoperative nausea and vomiting in major gynaecological surgery. A prospective, randomized, double-blind clinical trial.

We conducted a prospective, randomized, double-blind clinical trial comparing droperidol 1.25 mg intravenously (i.v.) (group 1, n = 30), ondansetron 4 mg i.v. (group 2, n = 30), or both (group 3, n = 30) in the prevention of postoperative nausea and vomiting (PONV) in the first 24 h following major gynaecological procedures under combined general and epidural anaesthesia. PONV was analysed by a linear nausea/vomiting score, incidence of nausea and vomiting, and the need for antiemetic rescue. Our results showed a similar incidence of nausea and vomiting in all groups (G1 33%, G2 40%, G3 43%). However, when comparisons were made according to the time of assessment, combination therapy resulted in significantly lower PONV than droperidol in the first hour (0% vs. 13%, P < 0.05) and second hour (0% vs. 13%, P < 0.05), and than ondansetron on the first hour (0% vs. 13%, P < 0.05). A trend persisted up to the fourth hour but was not statistically significant in either group. In conclusion, droperidol and ondansetron are effective agents in the prevention of PONV, and their combination seems to provide slightly better results than either drug alone.

Adolescent↗
PubMed2000

Autoimmune progesterone urticaria.

Autoimmune progesterone dermatitis is a rare cutaneous disorder characterized by recurrent and cyclic skin eruption with variable morphology, occurring during the luteal phase. A case of autoimmune progesterone urticaria in a 47-year-old woman is reported. An intradermal progestin test revealed a strong reactivity against this hormone. Treatment with tamoxifen and leuprolide acetate induced only a partial remission of urticaria. Bilateral oophorectomy was performed with absolute clearing of cutaneous lesions.

Autoimmune Diseases↗
PubMed1994

Contact dermatitis from textile dyes.

6 female patients with allergic contact dermatitis from textile dyes are described. Lesions were confined to areas in direct contact with the offending garment, mainly where friction and/or pressure occurred. Patch tests were positive to 2 or more disperse dyes. Thin-layer chromatography was carried out on the dyes extracted from fabrics of 3 patients, for the identification of textile dyes.

Adolescent↗
PubMed1993

Randomized comparative study of fleroxacin and chloramphenicol in typhoid fever.

This study compared fleroxacin, 400 mg daily for 7 or 14 days, with chloramphenicol, 50 mg/kg per day for 14 days, for the treatment of patients with typhoid fever in a multicenter study. A total of 184 patients were randomly assigned to the three treatment groups. Efficacy was determined by culture of blood and stool, overall clinical response, and time to defervescence. Safety was assessed by occurrence of adverse events and laboratory abnormalities. A total of 97 patients were evaluable for efficacy, 28 in the fleroxacin 7-day group, 35 in the fleroxacin 14-day group, and 34 in the chloramphenicol group. All showed rapid defervescence with high cure rates. Bacteriologic cure rates were 96% in the fleroxacin 7-day group, 97% in the fleroxacin 14-day group, and 85% in the chloramphenicol group. Clinical cure rates were 83-100% with fleroxacin and 82% with chloramphenicol. The time to defervescence was shorter for patients treated with fleroxacin than for those treated with chloramphenicol. All three treatment regimens were well tolerated. Fleroxacin, 400 mg daily for 7 days, appears to be satisfactory for the treatment of typhoid fever and compares favorably with the standard 14-day therapy with chloramphenicol.

Adolescent↗
PubMed1992

Allergic contact dermatitis in children. A multicenter study of the Portuguese Contact Dermatitis Group (GPEDC).

The authors report a study of allergic contact dermatitis in 329 Portuguese children of 14 years or younger. 170 children (64 male and 106 female) reacted to 1 or more allergens. Most of these were in the 11-14 years group. The main allergens were nickel, thimerosal, cobalt, mercury, fragrance-mix and potassium dichromate. Nickel reactivity predominated in females over the whole group, but a greater number of males younger than 5 years reacted to nickel. The number of positive reactions increased with age, but this was not accompained by an increase in the % of relevant tests. 12 children, all of them 13 or 14 years-old, had an occupational allergic contact dermatitis.

Adolescent↗
PubMed1992

Cytogenetics and karyosystematics of South American oryzomyine rodents (Cricetidae: Sigmodontinae). IV. Karyotypes of Venezuelan, Trinidadian, and Argentinian water rats of the genus Nectomys.

Bone marrow chromosomes were studied in South American water rats of the genus Nectomys from Venezuela, Trinidad, and Argentina. Specimens of N. squamipes from western and southern Venezuela showed a 2n = 52-53 karyotype, whereas a 2n = 56-57 karyotype was found in specimens from northeastern Argentina. In both cases, odd karyotypes can be explained by the presence of a supernumerary chromosome. In contrast, water rats from northeastern Venezuela and Trinidad showed a strikingly reduced 2n = 16-17 polymorphic chromosome complement. Six different karyomorphs were found among the latter, which may have resulted from a combination of pericentric inversions in two pairs of autosomes and a centromeric fusion in another autosomal pair. It is proposed that the new 2n = 16-17 cytotypes belong to a species of its own, for which the name N. palmipes is suggested.

Animals↗
PubMed1991

Patch testing in children: a study of 562 schoolchildren.

562 schoolchildren from Oporto were patch tested with the standard series of the Portuguese Contact Dermatitis Group (GPEDC). 13.3% of the children had positive reactions, the most common being to neomycin, thimerosal, para-tertiary-butylphenol-formaldehyde (PTBPF) resin and fragrance-mix. Thus contact allergy in children seems not to be as unusual as previously thought.

Adolescent↗