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Biomedical subjects

F A Silva

Publications and source records attributed to F A Silva.

17 recordsLinked to original sources

Retinoid signaling and cardiac anteroposterior segmentation.

Establishment of anterior-posterior polarity is one of the earliest decisions in cardiogenesis. Specification of anterior (outflow) and posterior (inflow) structures ensures proper connections between venous system and inflow tract and between arterial tree and outflow tract. The last few years have witnessed remarkable progress in our understanding of cardiac anteroposterior patterning. Molecular cloning and subsequent studies on RALDH2, the key embryonic retinaldehyde dehydrogenase in retinoic acid (RA) synthesis, provided the missing link between teratogenic studies on RA deficiency and excess and normal chamber morphogenesis. We discuss work establishing the foundations of our current understanding of the mechanisms of cardiac anteroposterior segmentation, the reasons why early evidence pointing to the role of RA in anteroposterior segmentation was overlooked, and the key experiments unraveling the role of RA in cardiac anteroposterior segmentation. We have also integrated recent experiments in a model of cardiac anteroposterior patterning in which RALDH2 expression determines anteroposterior boundaries in the heart field.

Animals↗

Effects of phenolic propyl esters on the oxidative stability of refined sunflower oil.

The oxidative stability of refined sunflower oil in the presence and in the absence of propyl caffeate (PC), propyl hydrocaffeate (PHC), propyl ferulate (PF), and propyl isoferulate (PI) has been evaluated according to the Rancimat method. The antioxidant activity of the phenolic derivatives was compared with that obtained with native [alpha-tocopherol (alpha-TOH)] and synthetic [propyl gallate (PG)] antioxidants. The results allow the establishment of a decreasing order of antioxidant power: PG > PHC > PC >> alpha-TOH > PI > PF. The oxidative stability was improved neither by the addition of PF nor by a supplement of alpha-TOH. Moreover, a positive antioxidant effect was obtained for PC that was placed between those of alpha-TOH and PG. The antioxidant activity of PHC was higher than that of its analogue (PC). A dose-dependent effect was observed for PG, PHC, and PC. A chain-breaking mechanism was proposed for the antioxidant activity of propyl phenolic esters because the same ranking order of efficacy was obtained for their antiradical activities evaluated by using the 2,2-diphenyl-1-picrylhydrazyl radical method.

Antioxidants↗

Left ventricular mass and function in young obese women.

OBJECTIVE: Obesity is associated with a high mortality rate due to cardiovascular disease. Left ventricular (LV) hypertrophy has been described in relation to obesity. The aim of this study was to evaluate echocardiographically the LV mass and function in young obese women as compared to lean women with similar characteristics. DESIGN: Prospective study. SUBJECTS: Eighty-two young women (< or =40 y), with obesity degree varying from I to III (BMI from 30 to 50 kg/m2) were compared to eighty young lean women. All of them were normotensive, none had cardiovascular complaints or any previous history of pulmonary disease, and none were taking any medication. The LV mass was calculated by the Devereux and Reichek formula. RESULTS: The LV mass was strongly increased in all obese groups (P<0.00003 to 0.000005) compared to lean subjects. LV mass adjusted indexes for height, BMI or volume were also increased compared to lean subjects and when adjusted for weight it was decreased. However when comparing LV mass/body surface area index this difference was not statistically significant. The linear regression analysis showed a strong association between the degree of obesity and LV mass, (r=0.52, P<0.001). Systolic and diastolic function in obese patients were similar to lean subjects, except for a lower E/A ratio in the obese group (P=0.005). CONCLUSION: In asymptomatic young obese women, there are some echocardiographic findings suggesting early cardiac involvement that seems to be related to the degree of obesity.

Adult↗

Phenolic acids and derivatives: studies on the relationship among structure, radical scavenging activity, and physicochemical parameters.

The antiradical activity of caffeic acid (1), dihydrocaffeic acid (5), and their corresponding n-alkyl esters was evaluated by using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(*)) method. Dihydrocaffeic acid (5) was the most potent compound, having an antiradical effect higher than that of (+/-)-alpha-tocopherol, whereas caffeic acid (1) was less efficient. Esterification of the carboxyl group of dihydrocaffeic acid (5) had a dramatic effect on its antiradical potency, but similar effects were not observed for caffeic acid (1) derivatives. The n-alkyl esters of both phenolic series had similar potencies, and their antiradical activities were independent of the alkyl chain length. Dose-dependent scavenger effects were found in both series. Acid-base properties of the compounds, evaluated by using potentiometry and spectrophotometry, showed that the catechol moiety had pK(a2) and pK(a3) values of 9. 24-9.02 and 11.38-10.99 in the dihydrocaffeic series and 8.48-8.24 and 11.38-11.07 in the caffeic series, respectively. Antiradical activity and pK(a) values of the compounds were not related.

Antioxidants↗

Male pseudohermaphroditism due to 17 beta-hydroxysteroid dehydrogenase 3 deficiency. Diagnosis, psychological evaluation, and management.

Ten male pseudohermaphrodites with 17 beta-hydroxysteroid dehydrogenase 3 (17 beta-HSD3) deficiency were evaluated in 1 clinic with an average follow-up of 10.1 years. The diagnoses were made by demonstrating low to normal serum testosterone levels, high androstenedione levels, and high ratios of serum androstenedione to testosterone in the basal state or after treatment with human chorionic gonadotropin. The molecular features of the underlying mutations were identified in all 7 families. Two additional males in the same families are believed to be affected on the basis of history obtained from family members. All of the 46,XY individuals in these families were registered at birth and raised as females (despite the presence of ambiguous genitalia in all or most), and all virilized after the time of expected puberty due to a rise in serum testosterone to or toward the normal male range. The age at diagnosis varied from 4 to 37 years. Ten individuals were studied by the same psychologist, and change of gender role (social sex) from female to male occurred in 3 subjects and in the 2 presumed affected subjects not studied. The individual with the highest serum testosterone level maintained female sexual identity, and in 2 families some of the affected males changed gender role and others did not. Thus, while androgen action plays a role in the process, additional undefined psychological, social, and/or biologic factors must be determinants of gender identity/role behavior. Management of the 7 individuals who chose to maintain female sex roles included castration, clitoroplasty, vaginal enlargement procedures when appropriate, treatment of hirsutism, cricoid cartilage reduction, and estrogen replacement. Three of the 7 are married (2 twice), 1 is involved in a long-term heterosexual relationship, 1 is engaged to be married, and the other 2 are not married and not believed to be sexually active. The 3 subjects who changed gender role behavior to male underwent hypospadias repair, and 1 was given supplemental testosterone therapy. One of these men is divorced, and the other 2 (aged 29 and 35 years) are unmarried. The diagnosis in 8 of these subjects was made after the time of expected puberty; it is unclear whether the functional and social outcomes would have been different if the diagnosis had been made and therapy begun earlier in life.

17-Hydroxysteroid Dehydrogenases↗

Comparison of left ventricular mass and function in obese versus nonobese women <40 years of age.

We evaluated, through Doppler echocardiography, left ventricular (LV) mass and function in 82 obese young women (aged <40 years) who were asymptomatic, without any cardiovascular or pulmonary disease compared with a lean control group matched by age and height. LV mass, LV mass/height, and LV mass/volume were increased in obese women, and a lower LV E- and A-wave velocity ratio was noted, suggesting early cardiac involvement.

Adult↗

Yellow fever vaccination during pregnancy and spontaneous abortion: a case-control study.

OBJECTIVE: To assess a possible association between Yellow fever (YF) vaccine (inadvertently) administered during early pregnancy and spontaneous abortion. METHOD: A hospital-based case-control study conducted in a Brazilian town after a YF vaccine campaign that followed an epidemic of dengue. The study included 39 women who attended a university hospital with spontaneous abortion (cases) and 74 pregnant women attending the antenatal clinic of that hospital (controls). RESULTS: The crude odds ratio (relative risk estimate) of this association was 2.49, which dropped to 2.29 (95% CI 0.65-8.03) when adjusted for several confounders by multiple logistic regression. Dengue and exposure to organophosphate insecticide fogging during pregnancy were not associated with spontaneous abortion. CONCLUSION: This study, although small and with low power, provides some evidence that women vaccinated with YF vaccine during early pregnancy have an increased risk of having spontaneous abortion. Based on these findings a sensible recommendation should be to avoid YF vaccination of pregnant women unless their risk of acquiring YF outweighs the risk of vaccine-related abortion.

Abortion, Spontaneous↗

Management of ambiguous genitalia in pseudohermaphrodites: new perspectives on vaginal dilation.

OBJECTIVE: To evaluate vaginal size and sexual activity after different techniques of feminization of external genitalia in patients with pseudohermaphroditism. DESIGN: Retrospective clinical study. SETTING: Pseudohermaphrodite patients seen at our institution. PATIENT(S): Three female and 20 male pseudohermaphrodites raised as females. INTERVENTION(S): Bilateral orchidectomy, feminization of external genitalia (clitoridectomy or clitoroplasty, urogenital sinus enlargement), and/or neovaginoplasty or vaginal dilation with acrylic molds. MAIN OUTCOME MEASURE(S): Psychological evaluation, vaginal size, and quality of intercourse. RESULT(S): All patients referred sexual drive to men. Fifty percent of the patients who were submitted to neovaginoplasty referred pain or bleeding during sexual intercourse. On the other hand, 87% of the patients who were submitted to vaginal dilation with acrylic molds, after genitoplasty or not, referred satisfactory sexual intercourse. All patients who were submitted to clitoroplasty referred orgasm and 29% of the patients submitted to clitoridectomy referred no orgasm. Of three patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency, two became pregnant and delivered normal children through cesarian section. CONCLUSION(S): In pseudohermaphrodites with female social sex, surgical correction of external genitalia performed in childhood and vaginal dilation with acrylic molds performed when they wished to start having sexual intercourse resulted in best outcome.

Adolescent↗

Male pseudohermaphroditism due to steroid 5alpha-reductase 2 deficiency. Diagnosis, psychological evaluation, and management.

Sixteen subjects (from 10 Brazilian families) with male pseudohermaphroditism due to steroid 5alpha-reductase 2 deficiency have been evaluated in 1 clinic. The diagnoses were made on the basis of normal plasma testosterone values, normal or low plasma dihydrotestosterone levels and high testosterone/dihydrotestosterone ratios in the basal state in postpubertal subjects or after treatment with either human chorionic gonadotropin or testosterone in prepubertal subjects. The analysis of the ratios of etiocholanolone to androsterone in urine confirmed the diagnosis in all subjects who were tested, and the molecular basis of the underlying mutations was established in 9 of the families. Fourteen of the individuals were evaluated by the same psychologist. All subjects but 1 were given a female sex assignment at birth. Three of the subjects (1 the sibling of an individual who has undergone female to male social behavior) maintain a female social sex; they have been gonadectomized and treated with exogenous estrogens. Ten of 13 subjects of postpubertal age underwent a change of social sex from female to male, had surgical correction of the hypospadias, and were treated with high-dose testosterone esters by parenteral injection and subsequently with dihydrotestosterone cream. These regimens brought serum dihydrotestosterone levels to the normal male range (or above) but resulted only in limited growth of the prostate and penis and, in some, increase in body and facial hair and enhancement of libido and sexual performance. Treatment of the prepubertal boys with testosterone and/or dihydrotestosterone resulted in a doubling of penis size.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

Three-dimensional reconstruction of fracture surfaces: area matching algorithms for automatic parallax measurements.

This paper describes two solutions for systematic measurement of surface elevation that can be used for both profile and surface reconstructions for quantitative fractography case studies. The first one is developed under Khoros graphical interface environment. It consists of an adaption of the almost classical area matching algorithm, that is based on cross-correlation operations, to the well-known method of parallax measurements from stereo pairs. A normalization function was created to avoid false cross-correlation peaks, driving to the true window best matching solution at each region analyzed on both stereo projections. Some limitations to the use of scanning electron microscopy and the types of surface patterns are also discussed. The second algorithm is based on a spatial correlation function. This solution is implemented under the NIH Image macro programming, combining a good representation for low contrast regions and many improvements on overall user interface and performance. Its advantages and limitations are also presented.

Algorithms↗

Cholelithiasis in cirrhotic patients. (Analysis of cholelithiasis among patients with liver cirrhosis in São Paulo, Brazil).

During the past 20 years, several authors have reported increased prevalence of cholelithiasis in liver cirrhosis. This biliary disease has been implicated with the deterioration of liver function, liver disease of alcoholic origin or even the presence of hypersplenism in this patient population. This study analyzes the incidence and possible factors which are responsible for promoting cholelithiasis in cirrhosis. The study included 110 cirrhotic patients of a private center specialized in treating liver diseases. The incidence of cholelithiasis was 27.3% (25.3% in males and 33.3% in females). There was no correlation between liver function defined by Child's classification or through the laboratory examinations (AST, ALT, AP, GGT, PT, Alb, TB, DB, PA) and the presence of gallstones. No evidence was found that the etiology of cirrhosis or the presence/absence of hypersplenism affected the prevalence of cholelithiasis in this population. In conclusion, an increased prevalence of cholelithiasis was verified in this population of cirrhotics but the pathogenesis is still obscure.

Adolescent↗