RESUMO

OBJECTIVES: To estimate the association between tuberculosis (TB) patients' race and patients' access to diagnostic testing in Brazil. In addition, we evaluated if the associations could be explained by a geographic codistribution between racial groups and diagnostic testing. STUDY DESIGN: It is a cross-sectional study based on secondary data from a national surveillance system of new TB cases diagnosed in 2015. METHODS: We evaluated the association between TB patients' race (independent variable) and the HIV testing and TB mycobacterial culture providing (dependent variables) with logistic regression models. We used multilevel models to consider different geopolitical levels (region, state and municipality). In addition, we used conditional logistic regressions matched by health-care unit. All models were adjusted by individual covariates associated with the outcomes. RESULTS: Compared with non-Afro-Brazilian patients, Afro-Brazilian patients had significantly lower odds to have had HIV testing [odds ratio (OR): 0.72; 95% confidence interval (CI): 0.69-0.75] and mycobacterial culture performed (OR: 0.74; 95% CI: 0.71-0.77). However, these statistically significant negative associations between Afro-Brazilian racial category and testing disappeared when patients were considered as nested in geopolitical contexts or matched for health-care unit. CONCLUSIONS: Afro-Brazilian TB patients had lower probability to have HIV test and mycobacterial culture performed. However, these associations seem to be macrodeterminated by the geographic distribution of both racial groups and diagnostic testing. Our findings can support the formulation of public policies aiming to mitigate regional disparities as a strategy to improve racial equity in access to healthcare. The approach presented can be applied in a range of scenarios to identify disparities, localize its source and support decision-making.

Assuntos

RESUMO

SETTING: The selection and transmission of drug-resistant strains of tuberculosis (TB) hamper disease control. OBJECTIVE: To identify health conditions, demographic and socio-economic factors, as well as individual factors associated with the incidence of drug-resistant TB (DR-TB), in Brazil at the municipal level. DESIGN: This was an ecological study covering Brazilian municipalities that had reported DR-TB cases in 2014. Associations were evaluated in a multilevel analysis using negative binomial regression. RESULTS: In the multilevel model, males (incidence rate ratio [IRR] 2.6, 95% confidence interval [CI] 2.3-2.93) and Black persons (IRR 1.82, 95%CI 1.61-2.05) had a higher risk of DR-TB. Compared with those aged 60 years, persons aged 15-59 years (IRR 1.72, 95%CI 1.40-2.11) also had a higher risk. The following contextual factors were associated with the incidence rate (IR) of DR-TB: proportion of previously treated patients (IRR 1.27, 95%CI 1.1-1.5), acquired immune-deficiency syndrome IR (IRR 1.13, 95%CI 1.02-1.25), Municipal Human Development Index (IRR 0.72, 95%CI 0.64-0.81) and the Gini coefficient (IRR 0.86, 95%CI 0.78-0.95). CONCLUSION: We have identified individual and contextual factors associated with the incidence of DR-TB. Our results may help improve integrated public health interventions aimed at controlling DR-TB in Brazil.

Assuntos

RESUMO

GumK is a membrane-associated glucuronosyltransferase of Xanthomonas campestris that is involved in xanthan gum biosynthesis. GumK belongs to the inverting GT-B superfamily and catalyzes the transfer of a glucuronic acid (GlcA) residue from uridine diphosphate (UDP)-GlcA (UDP-GlcA) to a lipid-PP-trisaccharide embedded in the membrane of the bacteria. The structure of GumK was previously described in its apo- and UDP-bound forms, with no significant conformational differences being observed. Here, we study the behavior of GumK toward its donor substrate UDP-GlcA. Turbidity measurements revealed that the interaction of GumK with UDP-GlcA produces aggregation of protein molecules under specific conditions. Moreover, limited proteolysis assays demonstrated protection of enzymatic digestion when UDP-GlcA is present, and this protection is promoted by substrate binding. Circular dichroism spectroscopy also revealed changes in the GumK tertiary structure after UDP-GlcA addition. According to the obtained emission fluorescence results, we suggest the possibility of exposure of hydrophobic residues upon UDP-GlcA binding. We present in silico-built models of GumK complexed with UDP-GlcA as well as its analogs UDP-glucose and UDP-galacturonic acid. Through molecular dynamics simulations, we also show that a relative movement between the domains appears to be specific and to be triggered by UDP-GlcA. The results presented here strongly suggest that GumK undergoes a conformational change upon donor substrate binding, likely bringing the two Rossmann fold domains closer together and triggering a change in the N-terminal domain, with consequent generation of the acceptor substrate binding site.

Assuntos

RESUMO

This study investigated the structural and biophysical characteristics of GumB and GumC, two Xanthomonas campestris membrane proteins that are involved in xanthan biosynthesis. Xanthan is an exopolysaccharide that is thought to be a virulence factor that contributes to bacterial in planta growth. It also is one of the most important industrial biopolymers. The first steps of xanthan biosynthesis are well understood, but the polymerization and export mechanisms remain unclear. For this reason, the key proteins must be characterized to better understand these processes. Here we characterized, by biochemical and biophysical techniques, GumB, the outer membrane polysaccharide export protein, and GumC, the polysaccharide co-polymerase protein of the xanthan biosynthesis system. Our results suggested that recombinant GumB is a tetrameric protein in solution. On the other hand, we observed that both native and recombinant GumC present oligomeric conformation consistent with dimers and higher-order oligomers. The transmembrane segments of GumC are required for GumC expression and/or stability. These initial results provide a starting point for additional studies that will clarify the roles of GumB and GumC in the xanthan polymerization and export processes and further elucidate their functions and mechanisms of action.

Assuntos

RESUMO

This study was undertaken to assess the in vitro activity of several antimicrobial agents against Brazilian isolates of Streptococcus pneumoniae and Haemophilus influenzae from 1996 to 2000. The antibiotics used were penicillin, amoxicillin/clavulanic acid (A/C), ampicillin, amoxicillin, cefaclor, cefdinir, cefixime, cefprozil, ceftriaxone, cefuroxime, azithromycin, clarithromycin, erythromycin, ciprofloxacin, levofloxacin, ofloxacin, chloramphenicol, clindamycin, doxycycline and trimethoprim/sulphamethoxazole (T/S). MICs were determined by the National Committee for Clinical Laboratory Standards (NCCLS) method and interpreted using NCCLS and PK/PD breakpoints. For S. pneumoniae 80.0% were penicillin susceptible, 18.3% intermediate, 1.7% resistant; most active agents were amoxicillin, A/C, ceftriaxone and levofloxacin; T/S was the least active agent. Beta-lactamase was produced by 13.7% of H. influenzae. All were susceptible to A/C, cefdinir, cefixime, ceftriaxone and quinolones. The least active agents were T/S and macrolides.

Assuntos

RESUMO

The mechanism of resistance was investigated in 39 macrolide-resistant clinical isolates of Streptococcus pneumoniae isolated from January 1997 to July 1999 in Santiago, Chile. Our results showed that 22 (56.5%) were macrolide-resistant, clindamycin-susceptible isolates (M phenotype) and 17 (43.5%) were macrolide and clindamycin resistant (MLS(B) phenotype). mefE gene was detected in all M phenotype, while ermB gene was detected in all MLS(B)-phenotype strains. Serotype 14 was the most frequent serotype among M-phenotype strains, and serotypes 19 and 23F were the most frequent serotypes in MLS(B) strains. These results demonstrate that both phenotypes of macrolide-resistant S. pneumoniae are found in Santiago, Chile, with the M phenotype predominating.

Assuntos

RESUMO

The aim of this in vitro study was to compare the tensile bond strength of 3 different bonding systems, associated to composite resins, bonded to dentinal surfaces. Forty-four dentinal surfaces were obtained from recently extracted human molars. A standardized smear layer was obtained and the surfaces were divided in 3 groups: G1) self etch + microhybrid composite; G2) single-component adhesive + phosphoric acid + microhybrid composite and G3) conventional system (acid + primer + bond) + microhybrid composite. Specimens made of composite resin were constructed in the shape of an inverted truncated cone with 3 mm of diameter. Tensile bond strength test was performed at the speed of 0.5 mm/min, and the results were expressed in MPa. The analysis of variance ANOVA (p < 0.05) determined that the type of bonding system used influenced tensile bond strength. Tukey's test, however, showed that the results of the comparison between G2 and G3 were the only statistically significant ones, with G2 showing greater values of tensile bond strength.

Assuntos

RESUMO

Thirty-two macrolide-resistant Streptococcus pyogenes isolates were found among 594 clinical isolates collected from 1990 to 1998 in Santiago, Chile, for an overall prevalence of 7.2%. Among the 32 resistant isolates, 28 (87.5%) presented the M phenotype and 4 (12. 5%) presented the MLS(B) phenotype. Serotyping and pulsed-field gel electrophoresis analysis showed genetic diversity among the resistant isolates.

Assuntos

RESUMO

To investigate the pathogenicity of Ureaplasma urealyticum and Mycoplasma hominis in preterm infants, we conducted a study to determine (1) frequency of isolation from cerebrospinal fluid and tracheal aspirate specimens and (2) clinical outcomes and effect of erythromycin treatment in ureaplasma-colonized infants. From the cerebrospinal fluid of 920 infants, U. urealyticum was isolated from 2 (0.2%) and M. hominis from none. From tracheal aspirate specimens from 224 infants, U. urealyticum was recovered from 37 (17%) and M. hominis from 4 (2%). Demographic characteristics and clinical outcomes were compared in very low birth weight infants (< 1500 gm) who were culture-positive or -negative for U. urealyticum. Although infants with positive results were less mature than their cohorts with negative results, there were no substantive differences in clinical outcomes between the two groups. Initiation of erythromycin treatment of infants with positive ureaplasma culture results at a mean age of 16.4 days did not appear to alter the clinical outcome. We conclude that in preterm infants (1) infection of the cerebrospinal fluid by U. urealyticum is infrequent, (2) ureaplasma organisms are frequently present in tracheal aspirate specimens but do not appear to be related to the presence or the subsequent development of respiratory disease, and (3) initiation of erythromycin treatment at 1 to 3 weeks of age does not alter the clinical course.

Assuntos

RESUMO

This study was conducted in order to assess prospective adherence to surveillance colonoscopy and fecal occult blood testing (FOBT) at 1 year following treatment for an index lesion among colorectal cancer and polyp patients. The investigation was carried out in cooperation with two gastroenterology and two surgical practices in Philadelphia and surrounding communities. Subjects in this study were patients who were treated for colorectal cancer (N = 9) or polyps (N = 169) and were recommended to undergo surveillance colonoscopy at 12 months following treatment. Overall, 96 (54%) subjects underwent surveillance colonoscopy. Of the 178 subjects included in the study, 52 (29%) were willing to participate in an assessment of FOBT sensitivity in surveillance. Of the 52 subjects who were mailed an FOBT packet, 24 (46%) actually returned specimen. Of the 24 patients who returned FOBTs, 17 (71%) also underwent colonoscopy, whereas only 10 (36%) of 26 patients who did not do FOBTs underwent colonoscopy. These findings indicate that adherence to surveillance is low, and that adherence to FOBT may be a marker for adherence to colonoscopy.

Assuntos

RESUMO

El éxito de la aplicación de la cirugia laparoscópica en enfermedades de la vesicula y en la apendicitis aguda, ha estimulado a los investigadores a desarrollar avances tecnológicos en un intento para tratar otro tipo de patologias del tracto digestivo. Despues de adquirir experiencia con diversas formas de laparoscopia, y mientras que se perfeccionaba la cirugia clinica del tracto blliar y del apendice y se adelantaban trabajos controlados en animales de laboratorio, se inició un programa piloto para cirugia laparoscópica del colon. Veinte pacientes con rango de edad entre 43 y 88 años, para una edad promedio de 57 años, se sometieron a resección del colon por laparoscopia. En 9 pacientes se realizó hemicolectomía derecha y en 8, sigmoidectomia. El procedimiento de Hartman (resección antero-inferior), y la resección perineoabdominal, fueron realizadas cada una en 1 paciente. Las indicaciones de la cirugia fueron los adenomas vellosos de gran tamaño o adenocarcinoma del colon, en 12 pacientes; enfermedad diverticular, en 5; endometrioma del sigmoide en 1; volvulus cecal en 1 y enfermedad inflamatoria intestinal en 1. El 80 por ciento de los pacientes toleraron dieta liquida en el primer dia posoperatorio y el 70 por ciento fueron dados de alta a las 96 horas con dieta corriente y deposición normal. Se presentaron tres complicaciones quirurgicas: 1) Un paciente presento sangrado posoperatorio que requirió 3 unidades de sangre, tratado sin cirugia. 2) Un paciente desarrolló un edema marcado de la anastomosis rectosigmoidea que requirió descompresion con sonda rectal. 3) Un paciente con cancer metastasico del colon presentó una obstruccion mecánica del intestino delgado 7 dias despues de la cirugia laparoscopica del colon. Aunque la cirugia laparoscopica esta considerada como un procedimiento en evolucion, se piensa que en el future sera potencialmente popular tanto como la colecistectomia laparoscopica.

Assuntos

RESUMO

To determine the pharmacokinetics of amphotericin B and 5-fluorocytosine in neonates, we measured serum concentrations at first dose and after 5 days of therapy by high-performance liquid chromatography in 13 neonates (mean birth weight 1.2 +/- 0.8 kg). The dose of amphotericin B was serially increased from 0.1 to 0.5 mg/kg/day in 10 infants but was decreased from 0.8 to 1.0 to 0.5 mg/kg/day in three infants. Amphotericin B concentrations were not detectable in infants receiving 0.1 mg/kg/day. Amphotericin B cerebrospinal fluid concentrations were 40% to 90% of serum values obtained simultaneously. Serum concentrations after oral administration of 5-fluorocytosine (dose 25 to 100 mg/kg/day) were detectable in all infants. We found extreme interindividual variability for the half-life, volume of distribution, and clearance for both drugs. Four infants had minimal elimination for both drugs between doses, a finding that correlates with rises in serum creatinine (greater than 0.4 mg/dl, 40 mumol/L) and blood urea nitrogen (greater than 10 mg/dl, 3.6 mmol/L). We recommend that the dose of amphotericin B given on the first day of treatment be greater than the usual testing dose of 0.1 mg/kg/day. We also recommend an initial 24-hour dosing interval for amphotericin B and 5-fluorocytosine. Serum drug concentrations may need to be monitored in high-risk, low birth weight infants.

Assuntos

RESUMO

Nutritional evaluations were undertaken on 102 Mexican-American preschool children who were below the 3rd percentile for height, weight, or head circumference. Serum vitamin A concentrations were low in 36 of 102 children (35%). Hair zinc concentrations were low in 28 of 96 children (29%) and plasma zinc concentrations were low in 35 of 94 children (37%). Children with only low height had a mean hair zinc level of 87.5 microgram/g, whereas those with only low weight had a mean level of 108.6 microgram/g and those with only low head circumference had a mean level of 100.1 microgram/g. There was no correlation of height percentiles with plasma zinc, hair zinc, or serum vitamin A. However, further studies are needed to determine if there is a relationship between growth retardation and zinc and/or vitamin A status in this population.

Assuntos

Assuntos

RESUMO

Mineral particles suspended in the Gulf of Mexico and Caribbean Sea were analyzed in relation to clay mineral distributions in bottom sediments, to sedimentation processes active in the region, and to the prevailing currents. Circulation in the upper layers of water flowing from the Caribbean, carrying a micaceous-rich mineral assemblage, has exercised an influence on mineral transport into the Gulf of Mexico, different from the montmorillonite-rich load delivered by the Mississippi River. Particulate matter, suspended in North Atlantic water and Amazon River discharge, enters the Caribbean through the Lesser Antilles and contributes to the detrital mineral content of Caribbean water, as does that carried by the wind.

Assuntos

Assuntos

Assuntos