Effect of activation mode of dual-cured resin cements and low-viscosity composite liners on bond strength to dentin

OBJECTIVES: The aim of this study was to investigate the influence of the activation mode of dual-cured resin cements and application of low-viscosity composite liners over self-primed dentin on bond strength (BS) of dentin-bonding agents (DBA). METHODS: Three DBA (Single Bond; Prompt L-Pop and Clearfil SE Bond), their respective resin cements (RelyX ARC and Panavia F) and two low-viscosity composites (Filtek Flow and Protect Liner F) were tested. After removing the buccal enamel surfaces of 25 bovine incisors, each flat dentin surface was sectioned longitudinally and divided into two similar parts. The dentin surfaces were wet-abraded with 600-grit SiC paper and randomly divided into 10 groups. Experimental groups comprised the use of DBA and their respective dual-cured resin cements, with or without light-activation of resin cements. The low-viscosity resin was used only for the self-etching systems, Prompt L-Pop and Clearfil SE Bond. Three resin cement cylinders (0.5mm high and 0.75mm diameter) were built on each bonded dentin surface, using a tygon tubing mold. After water storage for 24h, specimens were subjected to micro-shear testing. Data were statistically analyzed by two-way ANOVA and Tukey test. RESULTS: Light-activation of resin cements resulted in significantly higher BS for all DBA versus groups in which the resin cements were allowed to self-cure. The low-viscosity composite application increased the BS only for Prompt L-Pop. CONCLUSIONS: The bond strength of resin cements to dentin is reduced if light-activation is not employed. The use of a low-viscosity composite liner resulted in improved bond strength only for the single-step self-etching adhesive.     

Chromosome alterations associated with positive and negative lymph node involvement in breast cancer

Genetic heterogeneity is high in breast cancer, and hence it is difficult to link a specific chromosome alteration to a specific clinicopathologic feature. We examined clonal chromosome alterations in 45 breast carcinomas and statistically correlated the findings with clinical-histopathological parameters of the patients. The most common abnormalities were losses of chromosomes 19, 22, 21, X, and 17 and gains of chromosomes 9 and 18. A statistically significant correlation was found between clonal aberrations in chromosomes 17, 20, and 21 and positive lymph node involvement (LN+) and between clonal aberrations in chromosomes X and 6 and negative involvement (LN-). The average number of chromosome abnormalities was the same for both LN- and LN+ groups, and numerical and structural alterations were equally distributed. The mean number of chromosome aberrations did not differ significantly among tumor grades, but when aberrations were analyzed as monosomies, trisomies, and structural aberrations, a heterogeneous distribution was observed. Further cytogenetic investigation of breast tumors and their variable pathological features is undoubtedly necessary. The recognition and ultimately the molecular understanding of these abnormalities may improve breast cancer taxonomy and provide important prognostic information for both the patient and clinician.     

The sleep environment and its association with externalizing behaviors in a sample of low‐income adolescents

This study examined the sleep environment and its association with externalizing problems in adolescents attending an alternative high school. Participants included 114 students (56% female, 91% Black, mean age = 18.03, standard deviation [SD] = 1.49) from an alternative high school in a southeastern city. Most participants reported sleeping in a bed (83%) and at their house (72%) for 7 nights in the past week. Participants reported an average of 2.34 (SD = 1.86) past‐week ambient sleep disruptions. Sleeping fewer nights in their own home and experiencing higher levels of ambient sleep disruptions were associated with delinquency engagement. Fewer nights sleeping in a bed and higher levels of ambient sleep disruptions were associated with a significant arrest history. The sleep environment is important to consider when assessing sleep problems, particularly among low‐income adolescents living in urban environments. This information may inform comprehensive interventions to address behavioral health concerns.     

Characterization of non-beta-lactamase-mediated ampicillin resistance in Haemophilus influenzae.

Ampicillin resistance in Haemophilus influenzae is most often due to the plasmid-mediated production of TEM beta-lactamase. We studied four strains with high-level ampicillin resistance (MIC of 32 micrograms/ml with an inoculum of 10(5) CFU on solid media) which did not produce detectable beta-lactamase activity with two different detection methods. Two of the four strains contained extrachromosomal DNA by agarose gel electrophoresis. Conjugation failed to transfer ampicillin resistance; in contrast, transformation yielded ampicillin-resistant transformants in three of the four strains. These transformants did not contain detectable extrachromosomal DNA. In addition, mobilization of the resistance determinant by transformation to, or conjugation with, recombination-deficient strains was unsuccessful. DNA-DNA hybridization experiments revealed no homology of the DNA of these strains with two R plasmids (one coding for ampicillin resistance, the other for chloramphenicol and tetracycline resistance). We conclude that the genetic basis of the non-beta-lactamase ampicillin resistance in these strains appears to be chromosomally mediated. We investigated the mechanism of resistance in these strains. Enzymatic modification of penicillin was not detected by autoradiography of a thin-layer chromatogram of cell sonic extracts of three ampicillin-resistant transformant strains incubated with [14C]penicillin. To assess changes in permeability of the cell envelope, a plasmid coding for beta-lactamase was conjugated into these strains, and the hydrolysis of penicillin by intact cells and cell sonic extracts was compared. Only one of three transformant strains had significantly diminished permeability. Outer membrane proteins of these strains analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed apparent differences in comparison with the isogenic ampicillin-susceptible recipient strain. Autofluorography of a sodium dodecyl sulfate-polyacrylamide gel electrophoresis of Sarkosyl-solubilized crude membrane (the putative inner membranes) from these ampicillin-resistant transformant strains incubated with [3H]penicillin compared with the isogenic ampicillin-susceptible recipient strain revealed reduced binding to PBP 3 and 6, 3 and 4, or 4. In addition, affinity binding studies revealed decreased affinity of PBP 4 for ampicillin of all four transformants tested. We conclude that the major mechanism of resistance in these strains is altered penicillin-binding proteins; however, other mechanisms, including permeability, may also play a role.     

Pulmonary atresia with an intact interventricular septum and Ebstein's anomaly of the tricuspid valve

Patients with pulmonary atresia and intact ventricular septum have a poor prognosis with or without conventional surgical treatment. The best results of surgical treatment are obtained in those cases with a mild underdeveloped right ventricle and minor sinusoidal communication in the absence of important dysfunction of the tricuspid valve. We present five cases of pulmonary atresia with intact ventricular septum associated with dysfunction of the tricuspid valve. On the basis of radiographic, electrocardiographic and hemodynamic findings, this group of patients could not be distinguished from others without dysplasia of the tricuspid valve. Echocardiographic and angiocardiographic studies are mandatory in the differential diagnosis. A combination of systemic-pulmonary artery anastomosis associated with pulmonary valvotomy, when possible, and reconstruction of the right ventricular outflow tract are indicated for surgical solution of these malformations. However, tricuspid valve replacement is indicated in some cases.     

The interaction of oestrogen receptor status and pathological features with adjuvant treatment in relation to survival in patients with operable breast cancer: a retrospective study of 2660 patients

The oestrogen receptor (ER) status of 2660 patients with primary breast cancer has been related to the effect of different adjuvant systemic therapies on survival. However, as patients in the various treatment groups also had different prognostic features comparison between treatments was difficult. Over 90% of patients receiving tamoxifen (Tam) were postmenopausal compared with <20% of those receiving chemotherapy (CT). The latter had more positive nodes (85% vs 54%) and grade III tumours (54% vs 30%) than the Tam group. The combined CT and Tam group had similar characteristics to the CT alone group. The current reported increase in the proportion of women with ER+ tumours is explained by immunohistochemical analysis of ER and screening programmes. ER status was unrelated to survival in patients with small, low grade, node-negative tumours which was no different from that expected for age-matched women taken from the general population. The value of adjuvant treatment in these patients is therefore questionable. In those given any adjuvant treatment, survival of women with ER+ tumours was prolonged, with the greatest effect being seen in those receiving Tam. Patients with ER- tumours benefited from CT but the addition of Tam to CT improved survival only in those with ER+ tumours. ER status is now established as a major predictive factor for treatment selection in primary disease. Studies of prognostic and predictive markers may be invalidated by use of adjuvant therapy and selection criteria for different treatments. Survival will be influenced by both tumour biology and therapy. This important consideration must be remembered when analysing new markers, particularly in small studies.     

Markers of malnutrition after intestinal transplantation: the role of IGF-1 and calprotectin

The objective of this study is to valuate two biomarkers that may guide nutritional assessment during follow up after intestinal transplantation. We performed a retrospective study on prospectively collected data of insulin-like growth factor-1 (IGF-1) and effluent calprotectin in patients undergoing intestinal transplantation. Optimal nutritional status (ONS) was defined by using the Malnutrition Universal Screening Tool (MUST). IGF-1 and calprotectin were correlated with ONS by Pearson correlation. Eighteen cadaveric intestinal transplants were performed over 1,650 days (median follow up 425 days, range 29–1,650 days). Mean IGF-1 and calprotectin were significantly associated with independent nutrition. Seven patients became malnourished on one or more occasions. During malnutrition the mean IGF-1 was 22 ± 14 ng/ml and calprotectin 1,597 ± 1,055 mcg/g. Mean weight during episodes of malnutrition changed from 64.77 ± 8.76 kg to 59.05 ± 8.5 kg (–8.9 ± 1.25%). Both IGF-1 and calprotectin negatively correlated with ONS (Pearson’s r, –0.612, p = 0.014). Patients broadly aligned with three groups: nutritionally replete (normal IGF-1 and normal calprotectin), nutritionally equivocal (normal or low normal IGF-1 and high calprotectin), and malnourished (low IGF-1 and high calprotectin). Patients with low IGF-1 and high calprotectin may have a benign clinical presentation. However it is in their interests to have parenteral nutrition restarted pending further investigation.