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Biomedical subjects

M M Ferreira

Publications and source records attributed to M M Ferreira.

At least 19 recordsLinked to original sources
PubMed2001

Polycyclic aromatic hydrocarbons: a QSPR study. Quantitative structure-property relationships.

This work deals with 48 substances composed exclusively of unsubstituted six-membered fused aromatic rings. In the first step, physicochemical properties which are relevant in environmental studies such as the boiling temperature (Tb), the retention index (RI), n-octanol/water partition coefficient (KOW) and solubility (S) are related with a series of electronic, geometric and topological descriptors. Among them are: electron affinity, the difference between electron affinity and ionization potential (GAP), Wiener, and connectivity indexes, volume, surface area, length-to-breadth ratio and enthalpy of formation. In a second step, these properties were incorporated into the descriptor matrix to build several quantitative structure-property relationships and to obtain prediction rules for the log KOC, log KOA, bioconcentration factor (BCF) and Henry's law constant (H). Finally, the photo-induced toxicity of freshwater organism Daphinia-Magna is modeled using the following transformed electronic descriptors: electron affinity, ionization potential and Gap.

Animals↗
PubMed2001

[Surgery of atrial fibrillation with intraoperative radiofrequency].

Radiofrequency ablation is successful in most supraventricular tachyarrhythmias and the first results in percutaneous applications in atrial fibrillation have been published. At present, all the surgical techniques for the treatment of atrial fibrillation use extensive atrial incisions. A case report is presented of a 67 year old woman with chronic atrial fibrillation and rheumatic mitral and tricuspid valve disease. At surgery, pulmonary vein isolation was performed using a continuous linear ablation around the pulmonary veins, instead of using extensive atrial incisions. Concomitantly, a mitral valve replacement and tricuspid valve annuloplasty were performed. Five months after surgery the patient remains with a stable sinus rhythm surgery and in functional class I (NYHA).

Aged↗
PubMed2001

[Primary mesothelioma of the pericardium: a clinical case].

We describe a 33-years-old male patient, presenting with progressive right heart failure. After evaluation, the hypothesis of effusive-constrictive pericarditis was considered. Medical therapy was initiated with no clinical benefit. On the 15th day after admission he was proposed for surgical intervention. The intraoperatory examination revealed a thick pericardium adhering to the epicardium without a clear separation between them. Complete resection was technically impossible. The postoperative course evolved with worsening heart failure and development of renal failure requiring hemodialysis. A diagnosis of primary pericardial mesothelioma was made after histological evaluation. The patient died 8 days after surgery despite all efforts at hemodynamic compensation. Despite its rarity, this diagnosis should be considered in cases with rapid evolution of constrictive or effusive-constrictive pericarditis. The prognosis for pericardial mesothelioma is poor due to its late diagnosis, the difficulty of surgical excision and poor response to radio- or chemotherapy.

Adult↗
PubMed1999

Surgery for atrial fibrillation using radiofrequency catheter ablation: assessment of results at one year.

OBJECTIVE: The results obtained in 43 patients using direct intraoperative radiofrequency catheter ablation, as an alternative to surgical incisions, to perform atrial fibrillation surgery, are presented. METHODS: Forty-three patients with ages ranging from 43 to 74 years (x = 59), with chronic atrial fibrillation with an average duration 6+/-5 years were operated. Eleven patients suffered from clinically relevant tachyarrythmia and eight had previous thromboembolic events. All but one patient had concomitant mitral valve surgery. Direct intraoperative radiofrequency catheter ablation was used to perform endocardial bilateral isolation of the pulmonary veins from the left atrium. RESULTS: There were no local or general complications, namely bleeding or thromboembolic events. Of the 33 patients with more than 3 months of follow-up, 36% remained in atrial fibrillation (Santa Cruz score 0); 30% had Score 4; 18% had Score 3; 6% had Score 2; 9% had Score 1. CONCLUSIONS: We conclude that the use of intraoperative radiofrequency catheter ablation is fast and safe. Presently, this is our method of choice for surgical treatment of atrial fibrillation in mitral patients.

Adult↗
PubMed1999

Seroprevalence of HIV, HCV and syphilis in Brazilian prisoners: preponderance of parenteral transmission.

Between November 1993 and April 1994, our physicians' team interviewed and took blood samples of 631 prisoners randomly drawn from the largest prison of South America, which counted about 4700 inmates at that time. The interview consisted of questions related to risk behaviour for HIV infection, and the subjects were asked to provide blood for serological tests for HIV, hepatitis C and syphilis. Our main purpose was to investigate the relationship between HCV and injecting drug use as related to HIV seropositivity. Participation in the study was voluntary and confidentiality was guaranteed. Overall prevalences found were as follows: HIV: 16% (95% confidence interval (CI): 13-19%); HCV: 34% (95% CI: 30-38%), and syphilis: 18% (95% CI: 15-21%). Acknowledged use of ever injecting drug was 22% and no other parenteral risk was reported. Our results, as compared with other studies in the same prison, suggest that HIV prevalence has been stable in recent years, and that the major risk factor for HIV infection in this population is parenteral exposure by injecting drug use.

Adolescent↗
PubMed1998

[Atrial fibrillation surgery using intraoperative radiofrequency].

Radiofrequency ablation is successful in most supraventricular tachyarrhythmias and the first results in percutaneous applications in atrial fibrillation have been published. At present, all the surgical techniques for the treatment of atrial fibrillation use extensive atrial incisions. A case report is presented of a 67 year old woman with chronic atrial fibrillation and rheumatic mitral and tricuspid valve disease. At surgery, pulmonary vein isolation was performed using a continuous linear ablation around the pulmonary veins, instead of using extensive atrial incisions. Concommitantly, a mitral valve replacement and tricuspid valve annuloplasty were performed. Five months after surgery, the patient remains with a stable sinus rhythm surgery and in functional class I (NYHA).

Aged↗
PubMed1997

Weak acid inhibition of fermentation by Zygosaccharomyces bailii and Saccharomyces cerevisiae.

The inhibition kinetics of fermentation by Zygosaccharomyces bailii and Saccharomyces cerevisiae were evaluated for weak carboxylic acids. Several regression equations were tried to fit the experimental data, most cases being best fitted to exponential curves. The following parameters were determined: i) acid concentration responsible for 50% inhibition of fermentation (C50%); ii) area under the regression curve up to that concentration (A50%) and iii) exponential inhibition constant (k(i)). These parameters were compared according to their ability to express the inhibitory effect of each acid. In broad terms, the values of k(i) in association with minimum inhibitory concentrations (x(min)), were found best to express the inhibitory effect of the weak acids. However, C50% values were satisfactorily correlated with k(i). The value of A50% more precisely reflected the occasional stimulatory effect of low concentrations of weak acids. Comparison of inhibition parameters for Z. bailii and for S. cerevisiae revealed a higher resistance of the former to acetic, propionic, butyric and benzoic acids and similar resistance to caproic, caprylic and sorbic acids. Previous cultivation in the presence of acetic, propionic and benzoic acids showed a distinct influence on the resistance of both yeasts, although it did not always induce cellular adaptation. Fermentation inhibition showed a good correlation with the lipid solubility of weak acids suggesting that the acids interact with the hydrophobic regions of cell membranes.

Carboxylic Acids↗
PubMed1997

When and how to report results of surgery on atrial fibrillation.

OBJECTIVE: Several medical, interventional and surgical techniques are used to treat atrial fibrillation, aimed at different goals and having variable success rates. To be able to assess and compare all these techniques a methodology of study and a classification is proposed. METHODS: We developed a five grade score, named the Santa Crus Score, based upon the post-operative atrial rhythm and the effective atrial contraction. Score 0 corresponds to a persistence of atrial fibrillation, the presence of a regular rhythm is grade 1, 2 or 3 if there is no atrial contraction; right atrial contraction; or bilateral atrial contraction, respectively. Score 4 corresponds to sinus rhythm and bilateral atrial contraction. Surgery for atrial fibrillation was performed on 51 patients since 1992. All patients but two had associated mitrial surgery. Three different maze techniques were performed on 17 patients and the pulmonary veins isolation procedure on 34 patients. Patients were reassessed at 1, 6, 12, 24 and 36 months. RESULTS: After the maze I procedure atrial fibrillation eradication was achieved in 88% of patients but none scored 4. Three patients changed score during the first year. All maze III patients scored 0 initially and one changed to score 3 in the first year. Sixty percent of the maze IIIA patients scored 4, but one evolved to score 0 at 6 months. The pulmonary veins isolation technique eliminated atrial fibrillation in 71% of the patients initially, and in 60% after 1 year, and achieved a score of 4 in a third of the patients. CONCLUSION: This classification considers the intermediate grades of success that can occur with absence of atrial fibrillation and is applicable to all forms of therapy.

Adolescent↗
PubMed1996

Tuberculosis and HIV infection among female inmates in São Paulo, Brazil: a prospective cohort study.

Prison populations are at increased risk of both human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections, but among female inmates information on such risks remains scarce, especially in developing countries. Between October 1992 and November 1993, 350 women incarcerated at a prison in São Paulo, Brazil, were prospectively evaluated for HIV and M. tuberculosis infection and disease. Among them, 87 (25%) were HIV seropositive, and 20 (5.7%) had tuberculosis (TB). During the incarceration period, the purified protein derivative test conversion rate was 29% for HIV-positive and 32% for HIV-negative women. However, the incidence of TB was 9.9 per 100 person-years for HIV-positive and 0.7 per 100 person-years of incarceration for HIV-negative women (p < 0.0001). A multivariate analysis indicated that HIV infection (p < 0.0001) and incarceration time < 12 months (p < 0.05) were each associated with TB. These findings indicate that new transmissions of M. tuberculosis infection are common among female inmates and that HIV-infected women are more likely to acquire active disease during the first 12 months of incarceration. Because of their role in childbearing and care female inmates are an important potential source of transmission of M. tuberculosis, and new strategies to control the spread of TB in prisons need to be developed.

Adolescent↗
PubMed1996

[Anomalous insertion of mitral papillary muscles in obstructive hypertrophic myocardiopathy. Report of 2 cases].

Hypertrophic obstructive cardiomyopathy is a pathologic entity whose features are complex and diverse. Its surgical treatment generally requires myectomy. When the left ventricle outflow gradient is also due to mitral valve abnormalities, mitral valve replacement has been considered as the treatment of choice for the relief of the obstruction. We report two cases in which transesophageal echocardiography has allowed a good definition of this complex area of the heart and a better diagnosis and treatment of its components. Its use led to the diagnosis of abnormal papillary muscles inserted directly in the anterior leaflet of the mitral valve, with severe left ventricle outflow obstruction. Surgical treatment consisted of septal myectomy and excision of the muscles, thus preventing the need for mitral replacement. Systolic anterior motion of the mitral valve subsided and the outflow gradients became negligible. This new approach for the treatment of hypertrophic obstructive cardiomyopathy will be of benefit for patients in whom the anomalous insertion of the papillary muscles are recognized before surgery, thus preventing mitral valve replacement.

Adult↗
PubMed1986

Unilateral tubal twin gestation. A case report.

A case of unilateral tubal twin gestation is presented and the literature reviewed. No satisfactory explanation exists for the rarity of this condition relative to the incidence of intra-uterine multiple gestation.

Adult↗
PubMed1984

Hysterosalpingography in the assessment of infertility in black patients.

A series of 200 consecutive hysterosalpingograms for the evaluation of infertility in Black women attending a clinic at the Hillbrow Hospital, Johannesburg, is reviewed. A fallopian tube abnormality was found in 81,8% of cases, terminal hydrosalpinx being present in 64,4%. A uterine abnormality was present in 25% of cases. In comparison with other series it appears that our incidence of tubal lesions, especially terminal hydrosalpinx, is the highest yet reported. A high correlation with laparoscopic findings (75%) is documented. In our infertility clinic hysterosalpingography is one of the most valuable tools in the initial evaluation of the infertile couple.

Adult↗