[Dental fluorosis: quantification of Streptococcus mutans in school children from Mamiña, Chile. A longitudinal study]

BACKGROUND

High fluorine concentrations in drinking water are associated with a decrease in the amount of salivary S mutants. Taking into account that clinical dental fluorosis can appear with 1.5 ppm of fluorine in the drinking water, fluorine concentrations in Mamiña is 2.4 ppm.

AIM

To quantify salivary S mutans in school age children from Mamiña, a zone with a high fluorine content in the drinking water, during one year.

MATERIAL AND METHODS

During 1997 and 1998, dental health was assessed and salivary samples were obtained from 51 children (27 male) aged 10 +/- 2 years to quantify S mutans.

RESULTS

Most children studied had more than 10(5) salivary S mutans colony forming units. No changes in the rates of infection or dental health characteristics were observed during the observation year.

CONCLUSIONS

High fluorine content in the drinking water did not have an effect on salivary S mutans infection in this population.

[Count of salivary Streptococci mutans in pregnant women of the metropolitan region of Chile: cross-sectional study]

BACKGROUND

Salivary Streptococci mutans contamination is considered the main microbiological risk factor for the initiation of caries.

AIM

To assess the oral health of pregnant women, counting Salivary Streptococci mutants.

PATIENTS AND METHODS

One hundred seventy four pregnant women, in the first, second and third trimester of pregnancy, aged 27 +/- 5 years old, consulting at a public primary health center, were studied. Puerperal women that had their delivery two months before, were studied as a control group. Salivary samples were obtained and Streptococci mutans colonies were counted using quantitative and semiquantitative methods.

RESULTS

There was a good concordance between both counting methods. No differences in Streptococci mutans counts were observed among the three groups of pregnant women, but the latter as a group had higher counts than puerperal women. Women with more than 5 caries had also higher counts.

CONCLUSIONS

Semiquantitative Streptococci mutans counts are easy, rapid and non invasive and have a good concordance with quantitative counts in saliva.

Antibiotic treatment in preterm labor and intact membranes: a randomized, double-blinded, placebo-controlled trial

Although an association between microbial invasion of amniotic cavity and preterm birth has been extensively demonstrated, there is conflicting evidence regarding the benefits of antibiotic therapy in patients with preterm labor and intact membranes. We attempted to assess the efficacy of amoxicillin and erythromycin on pregnancy outcome in those patients. A randomized, double-blinded, placebo-controlled trial was designed and implemented. A total of 196 patients with singleton pregnancies and preterm labor with intact membranes (22-36 weeks) were randomly allocated to receive either antibiotics or placebo, plus adjunctive parenteral tocolysis, and 173 patients (antibiotics group n = 83 vs. placebo group n = 90) completed the treatment. The overall prevalence of microbial invasion of the amniotic cavity was 5.2% (9/173). No significant difference between both groups was found in maternal outcomes, including duration of randomization-to-delivery interval, frequency of preterm delivery, and frequency of clinical chorioamnionitis and endometritis. Rate of cesarean section was significantly higher in the placebo group (28% vs. 12%). Regarding neonatal outcome, no significant difference was detected between both groups in neonatal death, respiratory distress syndrome, proven sepsis, and birthweight. Suspected sepsis was significantly more frequent in the placebo group (6/90 vs. 0/78). The results of this trial indicate that amoxicillin and erythromycin do not prolong pregnancy in patients with preterm labor and intact membranes. A significant reduction in the rate of cesarean section was observed in patients receiving antibiotics. A significant reduction in the rate of neonatal suspected sepsis was also demonstrated.

[Intrauterine growth in full-term twins without risk factors]

Twins are analysed according to the intrauterine growth curve constructed for single fetus. The relationship of twins with length, weight, head circumference and the weight length-index is studied. Twins over 36 weeks gestation age, without maternal or fetal pathologies were selected. It is concluded the twins pregnancy "per se" constitutes on its own, a risk factor regarding the intrauterine growth curve, particularly in relation with the weight curve.

Maternal plasma volume expansion and hormonal changes in women with idiopathic fetal growth retardation

OBJECTIVE

To explore the mechanisms underlying the reduced maternal plasma volume associated with idiopathic fetal growth retardation (FGR).

METHODS

In 30 normotensive women with growth-retarded fetuses and 26 with normal-size fetuses, plasma volume was measured with a modified Evan's blue method. Plasma levels of atrial natriuretic peptide, plasma renin activity, aldosterone, estradiol, and progesterone, and urinary excretion of kallikrein, prostacyclin, and thromboxane A2 were measured at 34-40 weeks' gestation.

RESULTS

Compared with controls, gravidas with growth-retarded fetuses had a reduced plasma volume expansion (P < .01), similar atrial natriuretic peptide and plasma renin activity levels, and lower serum aldosterone (P < .001) and placental steroids (P < .03). These women also had decreased urinary kallikrein activity and prostaglandin excretion (P < .05). When both groups were combined, maternal plasma volume correlated significantly with birth weight (r = 0.53) and placental weight (r = 0.66).

CONCLUSION

Normotensive women with idiopathic FGR have reduced plasma volume expansion. Although the exact mechanisms of this change are unknown, we postulate that the lower maternal aldosterone levels and reduced levels of vasodilator substances, such as prostacyclin and kallikrein, may have a causal role.

Maternal hemodynamic adjustments in idiopathic fetal growth retardation

The hemodynamic characteristics of 11 normotensive gravidas with idiopathic fetal growth retardation (FGR), were compared with 11 controls of similar age, parity and body size. At weeks 36-38 of gestation, plasma volume was 3,161 +/- 121 ml in controls and 2,624 +/- 95 ml in the FGR group (p < 0.003); cardiac output (CO) was 6,191 +/- 132 ml/min in controls and 5,483 +/- 186 ml/min in the FGR group (p < 0.01). Total peripheral vascular resistance (TPVR) was lower in controls than in FGR (1,031 +/- 33 vs. 1,306 +/- 62 dyn/s/cm5; p < 0.001). Birth weight was correlated with both plasma volume (r = 0.61; p < 0.01) and CO (r = 0.53; p < 0.02) and inversely correlated with TPVR (r = -0.69; p < 0.001). These results are in line with the hypothesis that a reduced plasma volume leads to a lower CO and, secondarily, to reduced uterine blood flow and FGR.

Hemodynamic changes in underweight pregnant women

Twelve normal-weight and 12 underweight women were compared to test whether fetal growth retardation in underweight gravidas is related to inadequate maternal hemodynamic adjustments. Plasma volume (+/- standard error) was 3227 +/- 103 mL in normal-weight and 2731 +/- 84 mL in underweight women (P less than .002). Cardiac output was 6340 +/- 167 mL/minute in controls and 5689 +/- 213 mL/minute in underweight women (P less than .03). Total peripheral vascular resistance was lower in controls than in underweight subjects (1025 +/- 31 versus 1198 +/- 58 dyne/second/cm5). Mean birth weight was 2837 +/- 125 g in underweight women and 3362 +/- 106 g in controls (P less than .005). Similarly, placental weight was reduced in the underweight group. All infants delivered by control mothers had a normal birth weight, whereas six infants from underweight gravidas were growth-retarded. In all cases combined, maternal plasma volume correlated significantly with both birth weight (r = 0.6, P less than .002) and placental weight (r = 0.56, P less than .01); total peripheral vascular resistance also correlated significantly and inversely with newborn weight and placental weight. Cardiac output correlated only with placental weight (r = 0.54, P less than .02). These results are consistent with the hypothesis that underweight mothers are at higher risk of fetal growth retardation because of a smaller plasma volume and lower cardiac output.

Diffusion of medicaments within root canal dentin. A scanning electron microscopic study

Root canals of 21 maxillary human teeth were enlarged with reamers and flushed alternatively with sodium hypochlorite and hydrogen peroxide. After its mechanical preparation, root canals were dressed with camphorated paramonochloropherol and/or formocresol delivered by paper points. All three medicaments crystallize both on dentin walls and inside dentinal tubules. The clinical implications of these findings are discussed.

Complications and outcome of pregnancy in obese women

To examine the influence of obesity on obstetric performance, pregnancy outcome, and lactational performance, 163 mostly moderately obese gravidas were compared with age and parity-matched normal weight subjects. Significantly increased incidences of gestational hypertension, inadequate pregnancy weight gain, cesarean section, postpartum infections, and large-for-gestational age infants were observed in the study group. No significant increase in the incidence of diabetes, toxemia, breech presentation, postpartum hemorrhage, infant morbidity or lactational failure was noted in obese women. The mean birth weight of the infants of obese women was 163g greater than that of the control subjects; no difference was observed in infant length or gestational age. These results, while confirming that obesity is an important risk factor, suggest that methodological aspects of the previous studies may have contributed to magnify the severity of the problem.

A role for adrenaline and calmodulin in modulating cyclic AMP levels during the lactogenic cycle

The effect on lactose production of several external modulators of intracellular cyclic AMP was studied in rat mammary gland tissue slices and explants. Adrenaline, a beta-adrenergic receptor effector, forskolin, a direct adenylate cyclase activator and fluphenazine, a calmodulin inhibitor, all produced an increase in the intracellular level of cyclic AMP and a concomitant inhibition of lactose production. These results suggest a role for adrenaline and calmodulin in modulating cyclic AMP levels in mammary tissue during the lactogenic cycle.