Molar Incisor Hypomineralization in Colombia: Prevalence, Severity and Associated Risk Factors.

Aim: To determine prevalence, severity, and risk factors associated with Molar Incisor Hypomineralization (MIH) in schoolchildren between 6 and 15 years of age in Medellin, Colombia. Study design: We conducted a retrospective observational study including 1.075 children born and residing in Medellin, Colombia. A structured questionnaire addressing gestational period and first three years of child's life was administered to biological mothers. Two calibrated examiners established MIH diagnosis following the European Academy of Paediatric Dentistry criteria. Data were analyzed using descriptive statistics, bivariate analysis, and linear regression with a 5% significance. Results: Study population was predominantly male (70.7%), average age was 9.3±1.9 years. Prevalence of MIH was 11,2%. The majority of defects (85%) were mild. MIH was associated with alterations during last gestational trimester, type of childbirth and respiratory problems. Conclusion. MIH prevalence in schoolchildren between 6 and 15 years of age was 11.2%, being mild defects more frequently found. MIH was associated with different factors during pregnancy and the first three years of life.

Evaluation of the filling ability of artificial lateral canals using calcium silicate-based and epoxy resin-based endodontic sealers and two gutta-percha filling techniques.

AIM: To evaluate the ability of a calcium silicate-based sealer (iRoot SP) and an epoxy resin-based sealer (Topseal) using two gutta-percha filling techniques to fill artificial lateral canals (ALCs). METHODOLOGY: Seventy single-rooted human teeth were selected. Ten of these were used to obtain pilot data. Three ALCs were produced on mesial and distal surfaces of each root, one in each third, using size 10 engine reamers. The roots were randomly assigned to four experimental groups according to the filling technique and sealer used: 1, cold gutta-percha (single-point technique) with iRoot SP (SP-iR); 2, cold gutta-percha (single-point technique) with Topseal (SP-T); 3, continuous wave of condensation technique with iRoot SP (CWC-iR); and 4, continuous wave of condensation technique with Topseal (CWC-T). Digital periapical radiographs were taken. After the sealer had set, the roots were demineralized, cleared in methyl-salicylate and examined under a stereomicroscope. The depth of penetration of sealer and/or gutta-percha into the ALC was scored using a 5-point system, conducting an analysis on four surfaces. Filling scores of 0-1 were considered not acceptable, whilst scores of 2-4 were considered acceptable. Pearson's chi-square test was used to compare the experimental groups (P < 0.05). RESULTS: CWC-T was associated with the highest acceptable filling (57.8%), followed by CWC-iR (53.3%), SP-T (48.9%) and SP-iR (36.7%). Only when SP-iR was compared to the other groups, was the difference significant (P < 0.05). The apical third was associated with the lowest acceptable filling (37.5%). It was followed, in ascending order, by the middle (51.6%) and coronal thirds (58.3%). These differences were significant only when the apical thirds were compared to the other root thirds (P < 0.05). CONCLUSION: The calcium silicate-based sealer with continuous wave of condensation was more effective in artificial filling lateral canals than the single-point technique. The epoxy resin-based sealer with both filling techniques was effective in artificial filling lateral canals.

Exposure to indoor air pollutants (polycyclic aromatic hydrocarbons, toluene, benzene) in Mexican indigenous women.

UNLABELLED: Indoor air pollution is considered to be a serious public health issue in Mexico; therefore, more studies regarding this topic are necessary. In this context, we assessed exposure to polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds in: (i) women who use firewood combustion (indoor) for cooking and heating using traditional open fire; (ii) women who use firewood combustion (outdoor) for cooking and heating using traditional open fire; and (iii) women who use LP gas as the principal energy source. We studied 96 healthy women in San Luis Potosi, México. Urine samples were collected, and analyses of the following urinary exposure biomarkers were performed by high-performance liquid chromatography: 1-hydroxypyrene (1-OHP), trans, trans-muconic acid, and hippuric acid (HA). The highest levels of 1-OHP, trans, trans-muconic acid, and HA were found in communities where women were exposed to indoor biomass combustion smoke (or products; geometric mean ± s.d., 3.98 ± 5.10 µmol/mol creatinine; 4.81 ± 9.60 µg/l 1-OHP; 0.87 ± 1.78 mg/g creatinine for trans, trans-muconic acid; and 1.14 ± 0.91 g/g creatinine for HA). Our findings indicate higher exposure levels to all urinary exposure biomarkers studied in women who use indoor firewood combustion for cooking and heating (using traditional open fire). PRACTICAL IMPLICATIONS: High mean levels of 1-hydroxypyrene, t,t-muconic acid, and hippuric acid were found in women who use firewood combustion (indoor) for cooking and heating using traditional open fire and taking into account that millions of women and children in Mexico are living in scenarios similar to those studied in this report, the assessment of health effects in women and children exposed to polycyclic aromatic hydrocarbons and volatile organic compounds is urgently needed. Moreover, it is immediately necessary an intervention program to reduce exposure.

Accumulation of as, pb, and cu associated with the recent sedimentary processes in the colorado delta, South of the United States-Mexico boundary.

Sediment cores from the Colorado River (CR) remnant delta were used to assess the changing sedimentation and pollutant deposition processes in response to extensive human manipulation of the river. The cores are formed of alternating layers of clays and silts, with isolated sandy horizons. The clayey units are interpreted as periods of flood flows into this low gradient and meandering estuary after dam construction in the United States. The geochemistry of these sediments is particular because of the association of MnO with CaO rather than with the Fe(2)O(3)-rich clays. Past pollution of the CR delta by As, and probably also Pb and Cu, is recorded in some cores. Enrichment factors (EFs) >1 for these elements and their statistical association suggest anthropogenic inputs. The most likely sources for these element enrichments (especially As) are the arsenate-based pesticides used intensively in the area during the first half of the 20th century. The transport of these elements from the nearby agricultural lands into the present river reaches appears to have been driven in part by flooding events of the CR. Flushing by river and tide flows appear to be responsible of a lower pollutant deposition in the CR compared to the adjacent Hardy River (HR). Arsenic in the buried clay units of the HR has concentrations above the probable toxic effect level (PEL) for dwelling organisms, with maximum concentrations of 30 microg g(-1). Excess (210)Pb activities ((210)Pb(xs)) indicate that fluxes of this unsupported atmospheric isotope were not constant in this estuarine environment. However, the presence of (210)Pb(xs) does indicate that these sediments accumulated during the last ~100 years. Aproximate sediment ages were estimated from the correlation of historic flooding events with the interpretation of the stratigraphic record. They are in fair agreement with the reported onset of DDT metabolites at the bottom of one core.

Effect of metoprolol on myocardial function and energetics in patients with nonischemic dilated cardiomyopathy: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: This study examined the effects of metoprolol on left ventricular performance, efficiency, neurohormonal activation and myocardial respiratory quotient in patients with dilated cardiomyopathy. BACKGROUND: The mechanism by which beta-adrenergic blockade improves ejection fraction in patients with dilated cardiomyopathy remains an enigma. Thus, we undertook an extensive hemodynamic evaluation of this mechanism. In addition, because animal models have shown that catecholamine exposure may increase relative fatty acid utilization, we hypothesized that antagonism of sympathetic stimulation may result in increased carbohydrate utilization. METHODS: This was a randomized, double-blind, prospective trial in which 24 men with nonischemic dilated cardiomyopathy underwent cardiac catheterization before and after 3 months of therapy with metoprolol (n = 15) or placebo (n = 9) in addition to standard therapy. Pressure-volume relations were examined using a micromanometer catheter and digital ventriculography. RESULTS: At baseline, the placebo-treated patients had somewhat more advanced left ventricular dysfunction. Ejection fraction and left ventricular performance improved only in the metoprolol-treated patients. Stroke and minute work increased without an increase in myocardial oxygen consumption, suggesting increased myocardial efficiency. Further increases in ejection fraction were seen between 3 and 6 months in the metoprolol group. The placebo group had a significant increase in ejection fraction only after crossover to metoprolol. A significant relation between the change in coronary sinus norepinephrine and myocardial respiratory quotient was seen, suggesting a possible effect of adrenergic deactivation on substrate utilization. CONCLUSIONS: These data demonstrate that in patients with cardiomyopathy, metoprolol treatment improves myocardial performance and energetics, and favorably alters substrate utilization. Beta-adrenergic blocking agents, such as metoprolol, are hemodynamically and energetically beneficial in the treatment of myocardial failure.

Dobutamine stress echocardiography identifies hibernating myocardium and predicts recovery of left ventricular function after coronary revascularization.

BACKGROUND: The identification of hibernating myocardium is important in selecting patients who will benefit from coronary revascularization. This study was performed to determine whether dobutamine stress echocardiography (DSE) could identify hibernating myocardium and predict improvement in regional systolic wall thickening after revascularization. METHODS AND RESULTS: DSE was performed in 49 consecutive patients with multivessel coronary disease and depressed left ventricular function. Contractile reverse during DSE was defined by the presence of two criteria: (1) improved systolic wall thickening in at least two adjacent abnormal segments and (2) > or = 20% improvement in regional wall thickening score. Postoperative echocardiograms were evaluated for improved regional wall thickening in 25 patients at least 4 weeks after successful coronary revascularization. All studies were read in blinded fashion. Contractile reserve during DSE was present in 24 (49%) of 49 patients. The presence or absence of contractile reserve on preoperative DSE predicted recovery of ventricular function in the 25 patients who underwent successful revascularization. Thus, 9 of 11 patients with contractile reserve had improved systolic wall thickening after revascularization (hibernating myocardium), whereas 12 of 14 patients without contractile reserve did not improve (P = .003). CONCLUSIONS: Dobutamine stress echocardiography provides a simple, cost-effective, and widely available method of identifying hibernating myocardium and predicting improvement in regional left ventricular wall thickening after coronary revascularization. This technique may be clinically valuable in the selection of patients for coronary revascularization.

Evaluation of a personal computer-based quantitative coronary analysis system for rapid assessment of coronary stenoses.

Quantitative coronary analysis (QCA) is a technique that is rarely used because of the complexity and expense of existing systems. We studied a new personal computer-based QCA system that is capable of both geometric and densitometric analysis and compared it to a previously validated QCA system. Both systems performed extremely well in phantom analysis with 11 phantoms filmed in both 5-inch and 7-inch magnifications (R greater than 0.97 and SEE less than 0.33 mm for all modes). In 28 abnormal coronary angiograms analyzed at end diastole, stenosis and reference diameter correlations between the two systems were excellent (R = 0.90 and 0.96 and SEE = 0.43 and 0.33 mm for densitometric and geometric modes, respectively). Intraobserver and interobserver correlation was also excellent for both analysis modes. The new QCA system was able to perform analysis in approximately one third the time required by previously validated system and was much less expensive. We conclude that personal computer-based coronary analysis is an accurate, quick, and relatively inexpensive means for performing QCA that may help to make this technique feasible for nonresearch settings.

Cocaine-induced alterations in prostaglandin production in rabbit aorta.

To determine if alterations in endothelial prostaglandin production occur after long-term cocaine use, 26 New Zealand White rabbits were randomized to a low fat diet with (n = 12) or without (n = 14) daily intravenous cocaine (2 mg/kg body weight). Rabbits were killed at 6 or 12 weeks. Segments of aorta were examined in blinded manner for histologic changes. Additional slices were incubated in oxygenated Krebs buffer and release of 6-keto-prostaglandin F1 alpha, thromboxane B2 and prostaglandin E2 was assayed by radioimmunoassay. Minimal intimal histologic changes were seen in the aorta of three cocaine-treated rabbits. At 12 weeks 6-keto-prostaglandin F1 alpha was increased in the cocaine group (p = 0.063) as compared with levels in the control group. When rabbits killed at 6 and 12 weeks were considered together, increases in thromboxane B2 (p = 0.044) and a trend to increased prostaglandin E2 (p = 0.083) were seen in the cocaine group. The ratio of thromboxane B2 to 6-keto-prostaglandin F1 alpha was increased in the cocaine group compared with that in the control group (p less than 0.02). These data suggest that an increase in prostaglandin production occurs in the vascular endothelium of rabbits ingesting cocaine before gross histologic changes are evident. In addition, thromboxane B2 increases disproportionately with respect to 6-keto-prostaglandin F1 alpha, suggesting that a milieu for thrombosis may exist in users of cocaine.

Measurement of coronary flow using high-frequency intravascular ultrasound imaging and pulsed Doppler velocimetry: in vitro feasibility studies.

The recent development of intravascular ultrasound imaging offers the potential to measure blood flow as the product of vessel cross-sectional area and mean velocity derived from pulsed Doppler velocimetry. To determine the feasibility of this approach for measuring coronary artery flow, we constructed a flow model of the coronary circulation that allowed flow to be varied by adjusting downstream resistance and aortic driving pressure. Assessment of intracoronary flow velocity was accomplished using a commercially available end-mounted pulsed Doppler catheter. Cross-sectional area of the coronary artery was measured using a 20 MHz mechanical imaging transducer mounted on a 4.8 F catheter. The product of mean velocity and cross-sectional area was compared with coronary flow measured by timed collection in a graduated cylinder by linear regression analysis. Excellent correlations were obtained between coronary flow calculated by the ultrasound method and measured coronary flow at both ostial (r = 0.99, standard error of the estimate [SEE] = 13.9 ml/min) and distal (r = 0.98, SEE = 23.0 ml/min) vessel locations under steady flow conditions. During pulsatile flow, calculated and measured coronary flow also correlated well for ostial (r = 0.98, SEE = 12.7 ml/min) and downstream (r = 0.99, SEE = 9.3 ml/min) locations. That the SEE was lower for pulsatile as compared with steady flow may be explained by the blunting of the flow profile across the vessel lumen by the acceleration phase of pulsatile flow. These data establish the feasibility of measuring coronary artery blood flow using intravascular ultrasound imaging and pulsed Doppler techniques.