Caries-preventive potential of an adhesive patch after thermomechanical loading--a microbial-based in vitro study

PURPOSE: To assess the enamel-protective potential of a newly devised adhesive patch for smooth enamel sealing. MATERIALS AND METHODS: Approximal surfaces of 30 extracted molars were divided into three areas: the buccal thirds were treated with a flowable composite (Tetric Flow, Ivoclar Vivadent) and served as negative control sites, the lingual thirds were left untreated and served as positive control sites, and the middle thirds served as the test areas. This was sealed with either 1. a twofold application of an unfilled resin (Heliobond, Ivoclar Vivadent), 2. an adhesive prototype patch (Ivoclar Vivadent), or 3. an adhesive patch in combination with a flowable composite. After thermomechanical loading and demineralization in a microbial-based artificial caries chamber, demineralization depth was assessed using a confocal laser scanning microscope. RESULTS: Negative control sites treated with the flowable composite showed no signs of demineralization. Areas treated with the patch showed no signs of demineralization, irrespective of whether it was used in combination with a flowable composite or directly bonded to the enamel. Caries-like lesions in untreated sites showed a mean depth of 134.3 +/- 35.9 microm. Demineralization depth at sites treated with the unfilled resin was 76.2 +/- 26.5 microm (p = 0.023). CONCLUSIONS: Under the conditions of the present study, the adhesive patch under investigation completely protected the underlying enamel from demineralization. This merits further study to assess its potential as an interproximal sealant.     

Prevalence of HIV and syphilis in pregnant women in Leon, Nicaragua

The objective of this study was to determine the prevalence of HIV and syphilis and to identify risk factors among pregnant women visiting antenatal clinics in León, Nicaragua. During February to April 2004, blood samples from pregnant women were collected after written consent had been obtained. The samples were tested for antibodies against HIV and Treponema pallidum. A questionnaire was also completed. In total, 1,059 women were included. Antibodies against HIV were not detected in any of the women, whereas antibodies against T. pallidum were detected in 16 (1.5%). Risk factors for syphilis included illiteracy, lower education, and two or more pregnancies. HIV does not seem to be highly prevalent among pregnant women in León (prevalence, 0%; 95% CI, 0.0-0.3). The higher proportion of women infected with syphilis than found in earlier studies suggests that sexually transmitted diseases are circulating in the general population and highlights the increasing importance of HIV prevention.     

Effect of acute hyperglycemia and/or hyperinsulinemia on polymorphonuclear functions in healthy subjects

Abnormal immune functions of polymorphonuclear (PMN) cells occur in a variety of pathophysiological conditions. There exists a close link between glucose metabolism and PMN functions. The aim of this study was to assess the effect of short-term hyperglycemia and/or hyperinsulinemia on phagocytosis and respiratory burst of PMN cells in healthy subjects in vivo. The study was performed on 12 healthy subjects (mean age, 26.9+/-1.6 years; body mass index, 24.4+/-0.84 kg/m(2)). Acute hyperglycemia and/or hyperinsulinemia was induced by three 4-hour-long clamp studies-hyperglycemic hyperinsulinemic clamp (HHC), hyperinsulinemic euglycemic clamp (HEC), and isolated hyperglycemic clamp with insulin secretion blockade (HGC). Polymorphonuclear cell phagocytosis and PMN cell respiratory burst (mean percentage and mean fluorescent intensity of phagocyting/activated PMN cells, phagocytic, and respiratory burst indexes) were evaluated by flow cytometry under basal and stimulated conditions. Results detected during clamp studies were compared with those found during a control study with saline infusion. Significant reductions in the mean percentage of phagocyting cells measured under basal conditions after the HHC (6.7%+/-1.3% vs 12.1%+/-4.3%; P<.05) and HGC (4.5% +/-1.8% vs 9.9%+/-2.1%; P<.05) were found in comparison with the pre-clamp study period; however, these results did not differ significantly from those detected during the control clamp (CC) study. Significantly higher phagocytic (115.1+/-65 vs 35.8 +/-18.6; P<.05) and respiratory burst indexes (16.5+/-3 vs 10.1+/-1.4; P<.05) measured under basal conditions were found after HEC in comparison with the pre-clamp data. However, these data did not differ significantly from those found after the CC study. No significant differences in other parameters of detected PMN cell immune functions were found after HHC, HEC, and HGC. In conclusion, immune functions of PMN cells were not significantly influenced by short-lasting hyperglycemia and/or hyperinsulinemia induced in vivo by clamp techniques in healthy subjects compared to changes induced by the CC study. Further studies on the short-term effect of glucose metabolism on PMN functions in diabetic patients should be considered necessary.     

Absence of association between the multidrug resistance (MDR1) gene and inflammatory bowel disease

OBJECTIVE: The multidrug resistance (MDR1) gene encodes for P-glycoprotein, a drug efflux pump. Mice deficient for the MDR1a gene spontaneously develop colitis. In humans, a polymorphism in exon 26 (C3435T) is associated with reduced expression levels and function of MDR1. Currently there are controversial data on the association between MDR1 and inflammatory bowel disease (IBD). The purpose of this study was to examine the involvement of this gene in IBD in a large population of Dutch patients with IBD and family-based controls. MATERIAL AND METHODS: A total of 781 IBD cases and 315 controls were investigated. CD phenotypes were determined according to the Vienna Classification. Individuals were genotyped for six single nucleotide polymorphisms (SNPs) close to and in the MDR1 locus. This included the C3435T variant and six microsatellite markers close to and in the MDR1 locus. Single locus association analysis, haplotype association analysis and haplotype sharing statistic (HSS) were used to search for differences between patients and controls. RESULTS: No association was observed for any of the SNPs with IBD as a group, or for ulcerative colitis, Crohn's disease and Crohn's disease phenotypes, either by single locus or haplotype association analysis or by HSS. CONCLUSIONS: No association was observed between the MDR1 gene and IBD. This suggests that it is unlikely that MDR1 plays a role in IBD susceptibility.     

The Extent of Arsenic and of Metal Uptake by Aboveground Tissues of <Emphasis Type="Italic">Pteris vittata</Emphasis> and <Emphasis Type="Italic">Cyperus involucratus</Emphasis> Growing in Copper- and Cobalt-Rich Tailings of the Zambian Copperbelt

The extent of arsenic (As) and metal accumulation in fronds of the As hyperaccumulator Pteris vittata (Chinese brake fern) and in leaves of Cyperus involucratus, which grow on the surface of an old flotation tailings pond in the Zambian Copperbelt province, was studied. The tailings consist of two types of material with distinct chemical composition: (1) reddish-brown tailings rich in As, iron (Fe), and other metals, and (2) grey-green tailings with a lower content of As, Fe, and other metals, apart from manganese (Mn). P. vittata accumulates from 2350 to 5018 μg g⁻¹ As (total dry weight [dw]) in its fronds regardless of different total and plant-available As concentrations in both types of tailings. Concentrations of As in C. involucratus leaves are much lower (0.24–30.3 μg g⁻¹ dw). Contents of copper (Cu) and cobalt (Co) in fronds of P. vittata (151–237 and 18–38 μg g⁻¹ dw, respectively) and in leaves of C. involucratus (96–151 and 9–14 μg g⁻¹ dw, respectively) are high, whereas concentrations of other metals (Fe, Mn, and zinc [Zn]) are low and comparable with contents of the given metals in common plants. Despite great differences in metal concentrations in the two types of deposited materials, concentrations of most metals in plant tissues are very similar. This indicates an exclusion or avoidance mechanism operating when concentrations of the metals in substrate are particularly high. The results of the investigation show that Chinese brake fern is not only a hyperaccumulator of As but has adapted itself to high concentrations of Cu and Co in flotation tailings of the Zambian Copperbelt.     

Stereotactic radiotherapy for choroidal melanomas by means of HybridArc™

Purpose

Stereotactic radiotherapy (SRT) is suitable to treat ocular tumours. The optimal beam geometry for SRT, however, has not been defined. Here we evaluate a combination technique with dynamic conformal arcs (DCAs) and intensity-modulated static fields (IMRT), known as HybridArc? (HA).

Methods

For the first consecutive 25 cases with choroidal melanomas with volumes of 0.02 to 1.18?cm³ treated with 50?Gy in five fractions, the results with respect to dose conformity, homogeneity, and dose distributions were summarised. To describe the dose distribution at the planning target volume (PTV) boundary, we defined a spatially averaged dose gradient (SADG) and compared it with Paddick’s gradient index (GI). We made dosimetric comparisons between HA and other irradiation techniques.

Results

The PTVs ranged from 0.42 to 3.37?cm³. The conformity index (CI) was 1.25?±?0.15, and the homogeneity index (HI) 0.08?±?0.02. The SADG was (?3.5?±?0.5) Gy/mm or (?7.0?±?1.0) %/mm between the isodose levels 95 and 20%; local minima reached ?11.5?Gy/mm or ?22.9%/mm. The coefficient of determination for a nonlinear regression of GI on SADG was 0.072. After a median follow-up time of 19.6 months, local tumour control was 100% without any case of post-therapeutic enucleation. Two patients (8%) developed liver metastases.

Conclusion

SRT of ocular tumours by HA is highly appropriate, and HA is superior to intensity-modulated arc therapy (IMAT) concerning dose reduction in organs at risk (OARs). The novel gradient measure SADG is more informative than Paddick’s GI.

     

The role of p-glycoprotein in psychiatric disorders: a reliable guard of the brain?

A major component in the protection of the brain against blood-borne toxic influences is the multispecific efflux pump P-glycoprotein. This pump, a 170 kD protein, located at the luminal side of the capillary endothelial cells, has a large capacity and is capable of extruding a wide array of structurally divergent substrates. The brain uptake of the majority of antidepressants and antipsychotics, as well as many other psychotropic drugs and endogenous compounds is hampered by the activity of P-glycoprotein. In this review we discuss the current state of knowledge concerning the role of Pglycoprotein on pharmacokinetics of psychiatric drugs and the impact of modulation of P-glycoprotein on major psychiatric disorders. Relevant issues in reference to the function of P-glycoprotein and other efflux pumps in the blood-brain barrier related to mood disorders and schizophrenia are addressed, such as a possible role of P-glycoprotein as a susceptibility factor in depressive disorders and psychotic disorders.