Composite-composite Adhesion as a Function of Adhesive-composite Material and Surface Treatment.

OBJECTIVE: To evaluate the composite-to-composite repair interfacial fracture toughness (iFT) as a function of adhesive and composite repair material. METHODS AND MATERIALS: Beam-shaped composite specimens (21×4×3±0.2 mm) were prepared for each substrate material (Filtek Supreme Ultra [FSU] or Clearfil Majesty ES-2 [CME]) and artificially aged for 50,000 thermocycles (5-55°C, 20-second dwell time). Aged specimens were sectioned in half, and the resulting hemispecimens were randomly assigned to one of the different repair methods (n=10) based on the following variables: type of substrate composite (FSU or CME), acid etch (yes or no), adhesive type (Scotchbond Universal or Clearfil SE Bond 2), and type of repair composite (FSU or CME). The repair surface was prepared with a course diamond bur (Midwest #471271). When used, 37% phosphoric acid was applied for 20 seconds, rinsed, and dried. All adhesives and composites were applied according to manufacturers' instructions. After postrepair storage (100% humidity, 37°C, 24 hours), iFT was measured and expressed as MPa. Data were analyzed for statistical significance using a three-way analysis of variance and Tukey post hoc tests (α=0.05). RESULTS: iFT values ranged from 0.64 ± 0.19 MPa to 1.28 ± 013 MPa. Significantly higher iFT values were achieved when FSU was used as the repair composite resin regardless of the substrate composite resin (p<0.001). Clearfil SE Bond 2 adhesive was associated with significantly higher iFT values for FSU substrate (p<0.001). The etching procedure had no significant effect on the iFT values of the repair procedures (p>0.05). CONCLUSIONS: Composite repair strength is adhesive and composite dependent. Repair strength appears to be higher when FSU is the repair composite regardless of the adhesive used.

Effect of Residual Bacteria on the Outcome of Pulp Regeneration In Vivo.

It is not known to what extent residual infection may interfere with the success of pulp regeneration procedures. The aim of this study was to determine, radiographically and histologically, the effect of residual bacteria on the outcome of pulp regeneration mediated by a tissue-engineered construct as compared with traditional revascularization. Periapical lesions were induced in 24 canine teeth of 6 ferrets. After disinfection with 1.25% NaOCl and triple antibiotic paste, ferret dental pulp stem cells, encapsulated in a hydrogel scaffold, were injected into half the experimental teeth. The other half were treated with the traditional revascularization protocol with a blood clot scaffold. After 3 mo, block sections of the canine teeth were imaged radiographically and processed for histologic and histobacteriologic analyses. Associations between variables of interest were evaluated through mixed effects regression models. There were no significant differences between the 2 experimental groups in radiographic root development ( P > 0.05). There was a significant association between the presence of persistent periapical radiolucency and root wall thickness ( P = 0.02). There was also no significant difference in histologic findings between the 2 experimental groups ( P > 0.05). The presence of residual bacteria was significantly associated with lack of radiographic growth ( P < 0.001). The amount of dentin-associated mineralized tissue formed in teeth with residual bacteria was significantly less than in teeth with no residual bacteria ( P < 0.001). Residual bacteria have a critical negative effect on the outcome of regenerative endodontic procedures.

Painful Temporomandibular Disorder: Decade of Discovery from OPPERA Studies.

In 2006, the OPPERA project (Orofacial Pain: Prospective Evaluation and Risk Assessment) set out to identify risk factors for development of painful temporomandibular disorder (TMD). A decade later, this review summarizes its key findings. At 4 US study sites, OPPERA recruited and examined 3,258 community-based TMD-free adults assessing genetic and phenotypic measures of biological, psychosocial, clinical, and health status characteristics. During follow-up, 4% of participants per annum developed clinically verified TMD, although that was a "symptom iceberg" when compared with the 19% annual rate of facial pain symptoms. The most influential predictors of clinical TMD were simple checklists of comorbid health conditions and nonpainful orofacial symptoms. Self-reports of jaw parafunction were markedly stronger predictors than corresponding examiner assessments. The strongest psychosocial predictor was frequency of somatic symptoms, although not somatic reactivity. Pressure pain thresholds measured at cranial sites only weakly predicted incident TMD yet were strongly associated with chronic TMD, cross-sectionally, in OPPERA's separate case-control study. The puzzle was resolved in OPPERA's nested case-control study where repeated measures of pressure pain thresholds revealed fluctuation that coincided with TMD's onset, persistence, and recovery but did not predict its incidence. The nested case-control study likewise furnished novel evidence that deteriorating sleep quality predicted TMD incidence. Three hundred genes were investigated, implicating 6 single-nucleotide polymorphisms (SNPs) as risk factors for chronic TMD, while another 6 SNPs were associated with intermediate phenotypes for TMD. One study identified a serotonergic pathway in which multiple SNPs influenced risk of chronic TMD. Two other studies investigating gene-environment interactions found that effects of stress on pain were modified by variation in the gene encoding catechol O-methyltransferase. Lessons learned from OPPERA have verified some implicated risk factors for TMD and refuted others, redirecting our thinking. Now it is time to apply those lessons to studies investigating treatment and prevention of TMD.

COMT Diplotype Amplifies Effect of Stress on Risk of Temporomandibular Pain.

When measured once, psychological stress predicts development of painful temporomandibular disorder (TMD). However, a single measurement fails to characterize the dynamic nature of stress over time. Moreover, effects of stress on pain likely vary according to biological susceptibility. We hypothesized that temporal escalation in stress exacerbates risk for TMD, and the effect is amplified by allelic variants in a gene, catechol-O-methyltransferase (COMT), regulating catechol neurotransmitter catabolism. We used data from the Orofacial Pain: Prospective Evaluation and Risk Assessment prospective cohort study of 2,707 community-dwelling adults with no lifetime history of TMD on enrollment. At baseline and quarterly periods thereafter, the Perceived Stress Scale (PSS) measured psychological stress. Genotyped DNA from blood samples determined COMT diplotypes. During follow-up of 0.25 to 5.2 y, 248 adults developed examiner-verified incident TMD. PSS scores at baseline were 20% greater (P < 0.001) in adults who developed incident TMD compared with TMD-free controls. Baseline PSS scores increased by 9% (P = 0.003) during follow-up in cases but remained stable in controls. This stress escalation was limited to incident cases with COMT diplotypes coding for low-activity COMT, signifying impaired catabolism of catecholamines. Cox regression models confirmed significant effects on TMD hazard of both baseline PSS (P < 0.001), modeled as a time-constant covariate, and change in PSS (P < 0.001), modeled as a time-varying covariate. Furthermore, a significant (P = 0.04) interaction of COMT diplotype and time-varying stress showed that a postbaseline increase of 1.0 standard deviation in PSS more than doubled risk of TMD incidence in subjects with low-activity COMT diplotypes (hazard ratio = 2.35; 95% confidence limits: 1.66, 3.32), an effect not found in subjects with high-activity COMT diplotypes (hazard ratio = 1.42; 95% confidence limits: 0.96, 2.09). Findings provide novel insights into dynamic effects of psychological stress on TMD pain, highlighting that effects are most pronounced in individuals whose genetic susceptibility increases responsiveness to catecholamine neurotransmitters.

Sleep apnea symptoms and risk of temporomandibular disorder: OPPERA cohort.

The authors tested the hypothesis that obstructive sleep apnea (OSA) signs/symptoms are associated with the occurrence of temporomandibular disorder (TMD), using the OPPERA prospective cohort study of adults aged 18 to 44 years at enrollment (n = 2,604) and the OPPERA case-control study of chronic TMD (n = 1,716). In both the OPPERA cohort and case-control studies, TMD was examiner determined according to established research diagnostic criteria. People were considered to have high likelihood of OSA if they reported a history of sleep apnea or ≥ 2 hallmarks of OSA: loud snoring, daytime sleepiness, witnessed apnea, and hypertension. Cox proportional hazards regression estimated hazard ratios (HRs) and 95% confidence limits (CL) for first-onset TMD. Logistic regression estimated odds ratios (OR) and 95% CL for chronic TMD. In the cohort, 248 individuals developed first-onset TMD during the median 2.8-year follow-up. High likelihood of OSA was associated with greater incidence of first-onset TMD (adjusted HR = 1.73; 95% CL, 1.14, 2.62). In the case-control study, high likelihood of OSA was associated with higher odds of chronic TMD (adjusted OR = 3.63; 95% CL, 2.03, 6.52). Both studies supported a significant association of OSA symptoms and TMD, with prospective cohort evidence finding that OSA symptoms preceded first-onset TMD.

Intoxicación digitálica mortal / Fatal digitalis poisoning

No disponible

Remediation of the Wells G & H Superfund Site, Woburn, Massachusetts.

Remediation of ground water and soil contamination at the Wells G & H Superfund Site, Woburn, Massachusetts, uses technologies that reflect differences in hydrogeologic settings, concentrations of volatile organic compounds (VOCs), and costs of treatment. The poorly permeable glacial materials that overlie fractured bedrock at the W.R. Grace property necessitate use of closely spaced recovery wells. Contaminated ground water is treated with hydrogen peroxide and ultraviolet (UV) oxidation. At UniFirst, a deep well completed in fractured bedrock removes contaminated ground water, which is treated by hydrogen peroxide, UV oxidation, and granular activated carbon (GAC). The remediation system at Wildwood integrates air sparging, soil-vapor extraction, and ground water pumping. Air stripping and GAC are used to treat contaminated water; GAC is used to treat contaminated air. New England Plastics (NEP) uses air sparging and soil-vapor extraction to remove VOCs from the unsaturated zone and shallow ground water. Contaminated air and water are treated using separate GAC systems. After nine years of operation at W.R. Grace and UniFirst, 30 and 786 kg, respectively, of VOCs have been removed. In three years of operation, 866 kg of VOCs have been removed at Wildwood. In 15 months of operation, 36 kg of VOCs were removed at NEP. Characterization work continues at the Olympia Nominee Trust, Whitney Barrel, Murphy Waste Oil, and Aberjona Auto Parts properties. Risk assessments are being finalized that address heavy metals in the floodplain sediments along the Aberjona River that are mobilized from the Industri-Plex Superfund Site located a few miles upstream.

Integrin- and cadherin-mediated induction of the matrix metalloprotease matrilysin in cocultures of malignant oral squamous cell carcinoma cells and dermal fibroblasts.

Matrilysin is a matrix metalloprotease (MMP) overexpressed in a number of cancers including skin, head and neck squamous cell carcinomas, and prostate and colon adenocarcinomas. Matrilysin has been shown to play a role in the degradation of the basement membrane that separates epithelium from stroma allowing tumor cells to intravasate into the bloodstream and metastasize. Here, we show that an oral squamous cell carcinoma cell line (SCC-25) expresses low levels of promatrilysin when cultured alone. However, when SCC-25 cells are cocultured with human foreskin fibroblasts (HFF), there is a 40-fold induction of promatrilysin expression. We tested whether this induction of promatrilysin expression was due to the release of paracrine factors, cell-cell interactions, or cell-matrix interactions. Our results indicate induced promatrilysin expression is the result of both cell-cell and cell-matrix interactions. We demonstrate that beta1 integrins as well as cadherins, specifically N-cadherin and E-cadherin, are involved in the induction of promatrilysin expression. Our results are of general interest in relation to the regulation of MMP expression through cell surface receptor regulation. Further investigation may lead to the identification of novel targets for suppression of invasion and metastasis in oral tumors.

Synthetic peptides inhibit adhesion of human tumor cells to extracellular matrix proteins.

Human tumor cell progression and metastasis are partially dependent on the ability of a tumor cell to adhere to the proteins of the extracellular matrix (ECM) and survive at the distant location. Six novel D-amino acid-containing peptides were analyzed for their ability to adhere to human prostate tumor cells, support tumor cell adhesion, and inhibit tumor cell adhesion to ECM proteins or human dermal fibroblasts. Of these, two peptides called RZ-3 (kmviywkag) and HYD-1 (kikmviswkg) bound to tumor cell surfaces and compared favorably with the previously reported AG-73 (RKRLQVQLSIRT) L-amino acid peptide, as determined by fluorescence-activated cell sorting analysis. A scrambled peptide derivative of HYD-1, called HYDS-1 (wiksmkivkg), was not active. The RZ-3, HYD-1, and AG-73 peptides supported maximal cancer cell adhesion at 5 microg, 10 microg, and 50 microg/well, respectively. The ECM proteins fibronectin, laminin 1, and collagen IV supported maximal cell adhesion at 1 microg, >10 microg, and 50 microg/well, respectively. Prostate tumor cell adhesion to immobilized RZ-3 and HYD-1 peptides was inhibited by alpha2-6- and beta1-integrin-blocking antibodies. Conversely, tumor cell adhesion to a beta1-integrin-specific antibody was blocked by both RZ-3 and HYD-1. Epithelial cell adhesion to dermal fibroblasts was inhibited by HYD-1 and unaffected by the scrambled peptide, HYDS-1. Cell adhesion to immobilized peptides was unaffected by EDTA. The soluble RZ-3 and HYD-1 peptides inhibited tumor cell adhesion to each of the immobilized four ECM proteins (1.0 microg/well) in a time- and concentration-dependent manner. The IC(50) of the RZ-3 peptide for blocking adhesion to fibronectin, laminin 1, laminin 5, and collagen IV was 2.4 microg, 1.8 microg, 4.6 microg, and 2.8 microg/well, respectively. The IC(50) of the HYD-1 peptide for blocking adhesion to fibronectin, laminin 1, laminin 5, and collagen IV was 6.9 microg, 5.7 microg, >10 microg, and 6.2 microg/well, respectively. Taken together, these results indicate that RZ-3 and HYD-1 are biologically active D-amino acid-containing peptides that can themselves support tumor cell adhesion and can inhibit tumor cell adhesion to immobilized ECM proteins or dermal fibroblasts.

Acetaminophen versus acetaminophen with codeine after pediatric tonsillectomy.

OBJECTIVE: To compare the effectiveness of acetaminophen versus acetaminophen with codeine after pediatric tonsillectomy and adenoidectomy. STUDY DESIGN: Prospective, randomized, double-blind study. METHODS: Fifty-one children ages 3 to 12 years scheduled for outpatient tonsillectomy and adenoidectomy were studied. Patients were randomly assigned to receive acetaminophen or acetaminophen with codeine in unlabeled bottles for postoperative pain control. The Wong-Baker FACES pain rating scale was used to help children quantify their level of pain after surgery. The level of pain, quantity of pain medication required, presence of side effects, and the percentage of a normal diet consumed was recorded for 10 postoperative days. RESULTS: There was no difference (P > .05, all time points) in the level of postoperative pain reported by the parents and children in the two groups. The acetaminophen with codeine group tended to have increased problems with nausea, emesis, and constipation, but these differences did not reach statistical significance. Children in the acetaminophen group consumed a significantly higher percentage of a normal diet on the first 6 postoperative days (P < .05, all time points). CONCLUSION: There was no difference in the level of pain control provided by acetaminophen and acetaminophen with codeine as measured by the Wong-Baker FACES pain rating scale. Postoperative oral intake was significantly higher in children treated with acetaminophen alone.

Ankyloglossia: incidence and associated feeding difficulties.

OBJECTIVES: To determine the incidence of ankyloglossia (tongue-tie) in the well-baby population, and to determine whether patients with ankyloglossia experience breastfeeding difficulties. DESIGN: Prospective controlled study. SETTING: Tertiary care children's hospital. PATIENTS: A total of 1041 neonates in the well-baby nursery were screened for ankyloglossia. Those positively identified were invited to participate in the study. Mothers of newborns with ankyloglossia and mothers of a matched control group of unaffected newborns were contacted by telephone on a monthly basis for 6 months after their children were discharged from the hospital to determine the presence of breastfeeding difficulties. MAIN OUTCOME MEASURES: Incidence of ankyloglossia, percentage of infants successfully breastfed, and incidence of breastfeeding difficulties. RESULTS: Fifty newborns were identified with ankyloglossia, for an incidence of 4.8% The male-female ratio was 2.6:1.0. Of the 36 mothers of affected infants who were followed up and who intended to breastfeed, 30 (83%) successfully breastfed their infants for at least 2 months, compared with 33 (92%) of the 36 mothers of infants in the matched control group (P = .29). Breastfeeding difficulties were experienced by 9 (25%) of the mothers of infants with ankyloglossia compared with 1 (3%) of the control mothers (P<.01). CONCLUSION: Ankyloglossia, which is a relatively common finding in the newborn population, adversely affects breastfeeding in selected infants.

A two-stage test for ordered means in the poisson case with an example from mutagenicity testing.

It is shown how two-stage methods developed for continuous distributions can be used to construct two-stage tests for certain hypotheses pertaining to discrete distributions. Specifically, a two-stage test for ordered means in the Poisson case is presented. An example from mutagenicity testing is discussed and data from it are used to illustrate the methodology. Results of a Monte Carlo power study are presented as well as a brief table of critical values.

Perirenal malignant Schwannoma presenting as renal cell carcinoma.

Clinical and radiographic evaluation of a fifty-six-year-old male with microscopic hematuria led to radical nephrectomy for renal cell carcinoma. Histologic examination by light and electronmicroscopy was most compatible with malignant schwannoma. The tumor was close to the kidney without actual renal involvement. This case is of interest for both its rarity and its unusual presentation.