Effect of micrometer-scale metallic fillers on the mechanical and corrosion resistance properties of alternative materials for conservative dentistry

In conservative dentistry, glass-ionomer cements (GICs) have been proposed as substitutes for composite resins. This is because the latter, although widely used over the last 10 yrs, exhibit inadequate physico-chemical properties. Although the performance of a typical commercial GIC is not yet optimal for restorative dentistry, the addition of metallic filler could improve this. In this study, a series of commercially available GICs were incorporated in trial dental amalgams, whose mechanical and calorimetric properties and morphologies, were examined. The metallic component of these amalgams comprised one of three metallic fillers, each including micrometer-scale metal particles of a different shape. The corrosion resistance of the amalgams, in fluids simulating the oral cavity environment, was also studied. The addition of metallic filler to GIC produced a general improvement in mechanical properties. Of particular note were increases in the elastic modulus, up to around sixfold, with the addition of Valiant metallic filler to the GIC Fuji II, and of the stress at break, up to around fourfold, for the New Gen metallic filler/GIC Fuji II amalgam. In these cases, the mechanical properties of dentine were studied. Micrographic observations showed a highly compact structure of the added GICs, thus reflecting a reduction in shrinkage. Calorimetric and dilatometric analyses further confirmed the suitability for applications in preservative dentistry. Finally, with respect to corrosion resistance, the effect of the introduction of the metallic filler was beneficial in samples with low porosity.

Abnormal cardiac function in fetuses with increased nuchal translucency

OBJECTIVE

To evaluate cardiac function in structurally and chromosomally normal fetuses with increased nuchal translucency (NT).

METHODS

Forty-two structurally and chromosomally normal fetuses with increased NT at 11-14 weeks of gestation underwent fetal echocardiographic examination at 20-23 weeks. Fifty fetuses with normal NT values were considered as controls. Pulmonary and aortic peak velocity and time to peak velocities were measured as indices of ventricular systolic function. The ratios between the E-wave and A-wave (E/A) and the ratios between the E-wave and time velocity integral (E/TVI) at the level of both atrioventricular valves were evaluated as indices of ventricular diastolic function.

RESULTS

In fetuses with increased NT the E/A ratios were significantly decreased when compared to control fetuses at the level of both the mitral (0.52 +/- 0.09 vs. 0.60 +/- 0.10, P = 0.0002) and tricuspid (0.51 +/- 0.09 vs. 0.61 +/- 0.09, P < 0.0001) valves. Similar results were found for the E/TVI ratios (mitral valve 4.79 +/- 1.03 vs. 5.63 +/- 1.23, P = 0.0007 and tricuspid valve 4.40 +/- 0.88 vs. 5.19 +/- 0.82, P < 0.0001). No significant relationship was found between the degree of NT and the abnormalities in Doppler indices. There were no significant differences in Doppler systolic indices.

CONCLUSION

Structurally and chromosomally normal fetuses with increased NT have low E/A and E/TVI ratios at 20-23 weeks of gestation. These findings might indicate cardiac diastolic dysfunction.

Comparison of genotypic and phenotypic resistance patterns of human immunodeficiency virus type 1 isolates from patients treated with stavudine and didanosine or zidovudine and lamivudine

Sequencing of reverse-transcriptase genes and recombinant virus assays were performed on paired isolates from antiretroviral drug-naive patients randomized to stavudine and didanosine (group 1; n = 21) or zidovudine and lamivudine (group 2; n = 21) at baseline and after > or = 12 months of follow-up. The T215Y mutation emerged in 13 (61.9%) and 2 (9.5%) isolates in groups 1 and 2, respectively (P < .0001). Furthermore, in group 1, mutations associated with multidideoxynucleoside resistance were selected in 3 isolates. In group 2, all isolates carried the M184V mutation. The median fold changes in susceptibilities to zidovudine, stavudine, and lamivudine were 16.4 and 1, 2.2 and 0.6, and 4.5 and > 38 in groups 1 and 2, respectively (P < .0001, all comparisons). These results suggest that the combination of stavudine and didanosine is associated more frequently with the emergence of zidovudine resistance and a decrease in susceptibility to stavudine than the combination of zidovudine and lamivudine.

Reliability of Pd based dental alloys regarding to corrosion resistance and production processes

The knowledge of the relationship among chemical composition, microstructure, productive processes, functional properties, quality and price of the final product is an ever greater requirement for the firms producing dental alloys as well as for the dental laboratories making prosthesis. The present study deals with the evaluation of the corrosion resistance of high-Pd and Pd-Ag alloys by quantification of released ions following the recent European regulations suggested. Moreover the reliability of the alloys as far as concern their corrosion resistance was also investigated in relation to the different steps of alloy industrial production and restoration forming processes as well as after homogenization treatments followed by different cooling rate. The very complex microstructure of both alloys was greatly affected by the different casting conditions, deformation rate and thermal treatments used in alloy industrial production and prosthesis manufacturing. However the corrosion resistance of both alloys remained very good in all metallurgical states. The potentiodynamic tests allowed to distinguish among the structural conditions: the homogenization treatments, eliminating segregation inside the different phases, improved further the corrosion resistance of both alloys.

Blood flow velocity waveforms from fetal peripheral pulmonary arteries in pregnancies with preterm premature rupture of the membranes: relationship with pulmonary hypoplasia

OBJECTIVES

To measure fetal peripheral pulmonary artery velocity waveforms by Doppler ultrasonography in pregnancies complicated by premature rupture of membranes under 24 weeks' gestation and to relate the Doppler indices to the development of fetal pulmonary hypoplasia.

DESIGN

A prospective longitudinal study of fetal peripheral pulmonary artery velocity waveforms from premature rupture of membranes to delivery.

SUBJECTS

Twenty pregnancies complicated by premature rupture of membranes before 24 weeks of gestation and delivering after 26 weeks.

METHODS

Peripheral pulmonary artery velocity waveforms were recorded by Doppler technique at weekly intervals until delivery and Pulsatility Index (PI) calculated. Pregnancies were managed conservatively according to an institutional management protocol. Pulmonary hypoplasia was defined at autopsy by lung/body weight ratios and radial alveolar counts. Pulsatility Indices of fetuses developing pulmonary hypoplasia were compared with those with a normal lung development.

RESULTS

After premature rupture of membranes PI values were higher than normal reference limits for gestation, but no differences were found between the six fetuses which developed pulmonary hypoplasia and the remaining 14 fetuses with normal lung development. In this latter group PI values progressively decreased with advancing gestation (ANOVA for repeated measurements F = 11.61; P < or = 0.001), while they increased in fetuses developing pulmonary hypoplasia (F = 8.44; P < or = 0.001). As a consequence of these opposite trends significant differences in PI values were present between the two groups of fetuses from 2 weeks after the premature rupture of membranes. Two weeks after the premature rupture of membranes a PI value from the peripheral pulmonary arteries above the 95th centile had a sensitivity of 62.5%, specificity of 94.6%, positive predictive value of 83.3%, negative predictive value of 78.5% and relative risk of 3.88 (95th confidence interval 1.34-11.28) for the prediction of pulmonary hypoplasia.

CONCLUSION

The measurement of peripheral pulmonary velocity waveforms may help to establish the risk of developing pulmonary hypoplasia in pregnancies complicated by premature rupture of membranes.

Ni-Zr alloys: relationship between surface characteristics and electrocatalytic behavior

A relationship between electrocatalytic activity for the hydrogen evolution reaction and the surface composition of the electrode was established for Ni-Zr crystalline and amorphous alloys by means of secondary ion mass spectrometry (SIMS). Electrocatalytic activity was tested by means of cathodic polarization in 1 M KOH at 25 degrees C and the resulting exchange current density has been taken as a measure of catalytic efficiency. Surface activation treatment involved chemical etching in HF solutions; the consequent morphological and compositional surface changes were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical behavior of the pure elements (Ni and Zr) was also considered for comparison. All samples submitted to chemical etching in HF solutions showed an increase in electrocatalytic activity, particularly the alloy with the highest Ni content. The beneficial effect of chemical etching is due to dissolution of the zirconium oxide layer and to the formation of nanocrystalline Ni on the surfaces.

Taurine entry into perilymph of the guinea pig

Taurine is a beta-aminosulfonic acid and is a ubiquitous amino acid whose role in the cochlea is not well established. In this study, its entry from blood into perilymph was investigated in the guinea pig as animal model. The penetration rate of [3H]taurine (molecular weight 125) into the perilymph of the scala vestibuli was measured 1 and 2 h after the intravenous infusion of [3H]taurine in nephrectomized animals. Results showed a rate of penetration in perilymph related to plasma at 36 +/- 4.7% (n = 5) after 1 h and 43 +/- 5.6% (n = 5) after 2 h. Compared to the penetration rate of urea (molecular weight 60) and mannitol (molecular weight 186) reported previously in rats, a passive entry of taurine into perilymph through the blood-perilymph barrier is suggested.

Ultrasonographic assessment of the uterine cervix and interleukin-8 concentrations in cervical secretions predict intrauterine infection in patients with preterm labor and intact membranes

OBJECTIVE

Interleukin-8 concentrations in cervical secretions have been related to microbial invasion of the amniotic cavity and histological chorioamnionitis. Since a short uterine cervix may be a risk factor for intrauterine infection, we set out to determine the interrelationship between cervical-secretion interleukin-8 concentration, cervical length measured by transvaginal sonography and intrauterine infection in women with preterm labor and intact membranes.

DESIGN

The study group comprised 144 pregnant women admitted to hospital for preterm labor and intact membranes. At admission, interleukin-8 in cervical secretions was assayed. The uterine cervix was evaluated by transvaginal sonography and the cervical index (funnel length + 1)/cervical length) was measured. In all cases, amniotic fluid was obtained by amniocentesis immediately after cervical examination and was cultured for aerobic and anaerobic bacteria including Ureaplasma ureolyticum and Mycoplasma hominis. Placentas were analyzed at delivery for the presence of histological chorioamnionitis.

RESULTS

Forty-three per cent (62/144) of pregnancies delivered preterm and 12.5% (18/144) of the amniotic fluid cultures were positive. Placentas were available from 54 pregnancies which delivered preterm and histological chorioamnionitis was found in 59.2% (32/54) of the cases. Interleukin-8 concentrations in cervical secretions were significantly higher in the presence of microbial invasion of the amniotic cavity (median 1191.5 ng/ml, range 812-5234 ng/ml vs. median 109 ng/ml, range 12-2231 ng/ml; p < or = 0.0001) and histological chorioamnionitis (median 982.5 ng/ml, range 430-5234 ng/ml vs. median 435 ng/ml, range 40-1750 ng/ml; p < or = 0.0001). Similarly, higher values for cervical index were obtained in the presence of a positive amniotic fluid culture (median 1.23, range 0.35-5.88 vs. median 0.29, range 0.024-4.85; p < or = 0.0001) or histological chorioamnionitis (median 1.18, range 0.043-5.88 vs. median 0.562, range 0.040-2.48; p = 0.011). Multiple logistic regression analysis indicates significant independent associations with a positive amniotic fluid culture and histological chorioamnionitis for the cervical interleukin-8 concentrations (amniotic fluid culture positive > or = 850, histological chorioamnionitis > or = 450) and for the cervical index (amniotic fluid culture positive < or = 0.58, histological chorioamnionitis < or = 0.56).

CONCLUSIONS

Intrauterine infection is associated with increased interleukin-8 concentrations in cervical secretions and a short cervix. Their combined analysis may reduce the indications for invasive procedures and improve the selection of women in preterm labor who may benefit from antimicrobial treatment.

Interleukin-6 concentrations in cervical secretions in the prediction of intrauterine infection in preterm premature rupture of the membranes

The objective of this study was to determine the value of interleukin-6 (IL-6) in cervical secretion to diagnose microbial invasion of the amniotic cavity in patients with premature rupture of the membranes. Cervical secretions were sampled immediately before amniocentesis in 124 patients with singleton pregnancies and preterm premature rupture of the membranes. Gestational age ranged between 24 and 32 weeks. Amniotic fluid was cultured and IL-6 measured in amniotic fluid and cervical secretions. A total of 33.8% (21/124) of the amniotic fluid cultures had positive results. In cervical secretions the median concentration of IL-6 was 672 pg/ml (range 5-1,250) in the presence of intra-amniotic infection in contrast to 95.5 pg/ml (range 12-640) in women with negative amniotic fluid culture (p </=0.001). There were no differences between IL-6 concentrations in the cervical secretions of patients with or without obvious leakage of amniotic fluid. A significant relationship was found between IL-6 levels in amniotic fluid and in cervical secretions (rho = 0.74, p </=0.001). An IL-6 level in cervical secretions >200 pg/ml had a sensitivity of 78.5%, a specificity of 73.1% and a relative risk of 4.6 for intra-amniotic infection. Receiver-operator characteristics curve analysis showed that IL-6 assay in cervical secretions is comparable to IL-6 assay in amniotic fluid in predicting intra-amniotic infection (p = 0.468). In conclusion, intra-amniotic infection is associated with increased levels of IL-6 and concentrations in cervical secretions are related to amniotic levels. The measurement of IL-6 in cervical secretions may help to noninvasively identify intra-amniotic infection among pregnancies with preterm premature rupture of membranes.

The value of transvaginal ultrasonographic examination of the uterine cervix in predicting preterm delivery in patients with preterm premature rupture of membranes

The objective of this study was to compare the value of ultrasonographic assessment of the uterine cervix and amniotic fluid tests in the prediction of the interval from admission to delivery in patients with preterm premature rupture of membranes. Ninety-two patients admitted to the hospital for preterm premature rupture of membranes between 24 and 32 weeks of gestation underwent both transabdominal amniocentesis and transvaginal ultrasonographic evaluation of the uterine cervix. Amniotic fluid analyses included cultures for aerobic and anaerobic bacteria, mycoplasmas and ureaplasmas, white blood cell count and glucose and interleukin-6 determinations. The ultrasonographic variables evaluated were cervical length, presence of funneling and cervical index ((funnel length + 1)/cervical length). The outcome measure was the interval from admission to delivery. The median interval from admission to delivery was 4.5 days (range 0-36). An abnormal uterine cervix was associated with a short time interval (cervical length < or = 20 mm, median 2 days, range 0-14 vs. median 6 days, range 0-36; p < or = 0.0001; presence of funneling, median 3 days, range 1-31 vs. median 8 days, range 0-36; p < or = 0.001; cervical index > 0.50, median 2 days, range 0-7 vs. median 8 days, range 1-36; p < or = 0.0001). However, interleukin-6 concentration in the amniotic fluid was the best predictor of the interval from admission to delivery when compared to the ultrasonographic indices and to all the amniotic variables considered. Moreover, when a multiple model was applied, the cervical index significantly and independently improved the performance of interleukin-6 in the prediction of the interval from admission to delivery. These data suggest that the combined use of the amniotic fluid interleukin-6 assay and the cervical index in patients with preterm premature rupture of membranes provides a good prediction of the interval from admission to delivery, thus identifying a subgroup of patients at high risk of imminent delivery.

The diagnostic value of interleukin-8 and fetal fibronectin concentrations in cervical secretions in patients with preterm labor and intact membranes

The objectives of this study were 1) to evaluate interleukin-8 concentrations in cervical secretions in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes and 2) to compare the diagnostic value of interleukin-8 with fetal fibronectin determinations in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes. Interleukin-8 and fetal fibronectin were assayed in cervical secretions in 106 patients with singleton pregnancies and intact membranes admitted for preterm labor. Amniotic fluid obtained by amniocentesis was cultured and placentas (No = 43) analyzed for the presence of chorioamnionitis. The prevalence of pregnancies delivered preterm was 46.2% (49/106) and 15.09% (16/106) of amniotic fluid cultures were positive. Interleukin-8 levels in cervical secretions were significantly increased in patients who delivered preterm (p < or = 0.0001), in presence of positive amniotic fluid culture (p = 0.0016) and histological chorioamnionitis (p = 0.008) than in patients with negative findings. Receiver-operator characteristics curve analysis showed that an interleukin-8 value > 450 pg/ml is comparable to that of a fetal fibronectin value > 50 ng/ml in predicting preterm delivery (p = 0.247). Among patients who delivered preterm interleukin-8 concentrations > 860 pg/ml predicted a positive amniotic fluid culture with a sensitivity of 81.2% and a specificity 66.6%. Further, in patients who delivered preterm and had a negative amniotic fluid culture, IL-8 concentrations > 480 pg/ml predicted histological chorioamnionitis with a sensitivity 78.5% and specificity 61.5%. A positive fetal fibronectin > 50 ng/ml was not predictve of either a positive amniotic fluid culture or the presence of histological chorioamnionitis. In conclusion, increased concentrations of interleukin-8 and fetal fibronectin are associated with impending delivery and their diagnostic value seems comparable. However, interleukin-8 concentrations identify patients at risk of a positive amniotic fluid culture and the presence of histological chorioamnionitis. Measurement of interleukin-8 in cervical secretion is a non-invasive method to identify patients at risk for both preterm delivery and intrauterine infection.

[Surgical treatment of chronic pericardial effusions. Personal experience]

The authors report their experience about 15 patients surgically treated for chronic large pericardial effusion; in 12 cases the etiology was malignant neoplasm, while in the other 3 cases was inflammatory disease. In 4 patients a simple subxiphoid pericardial drainage was carried out, while in the other cases a pericardial window was performed. These cases were managed using an anterior left thoracotomy in 8 patients and a videothoracoscopy in 3. The authors conclude that pericardial window with videothoracoscopic approach is the preferable procedure, but it cannot be used in every case because a lot of patients have seriously compromised conditions and the use of this technique can be hazardous.

On the Deiters cell contribution to the micromechanics of the organ of Corti

We give the first estimate of Young's modulus of the proteinaceous beam that makes the stiffness of the Deiters cell phalangeal processes. We show that the fundamental mode of vibration of an isolated phalanx is overdamped due to the damping imposed by the surrounding fluid. Then we consider the mechanical couplings that have so far been neglected in the micromechanics of the organ of Corti. Conclusions are drawn concerning the lack of significance of some expected resonant behaviour of isolated outer hair cells.

Neuroendocrine Carcinoma of the Skin: A Case Report of “Multiple Neuroendocrine Carcinoma” Onset and Long-Term Remission after Chemotherapy

We herein report a case of “multiple neuroendrocine carcinoma” onset, with a torpid course, metastasis in the left breast, and an initial considerable sensitivity to the chemotherapy. We conclude that a re-evaluation of the studies on this neoplasia carried out to date is needed, in order to identify new regimens, which increase the complete response rates and their duration.

Allergic contact dermatitis of the lip margins from para-tertiary-butylphenol in a lip liner

We describe the use of gas chromatography with mass spectrometry (GC-MS) in the investigation of a case of allergic contact dermatitis of the lip margins caused by a lip liner. Patch testing identified sensitization to para-tertiary-butylphenol-formaldehyde resin (PTBP-FR), a resin glue frequently used in leather work but rarely found in cosmetics. Investigation specified the para-tertiary-butylphenol (PTBP) component of the resin as the hapten responsible for the allergic contact dermatitis, as well as for associated depigmentation.