Adhesive/Dentin Interface: The Weak Link in the Composite Restoration

Results from clinical studies suggest that more than half of the 166 million dental restorations that were placed in the United States in 2005 were replacements for failed restorations. This emphasis on replacement therapy is expected to grow as dentists use composite as opposed to dental amalgam to restore moderate to large posterior lesions. Composite restorations have higher failure rates, more recurrent caries, and increased frequency of replacement as compared to amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and premature failure. Under in vivo conditions the bond formed at the adhesive/dentin interface can be the first defense against these noxious, damaging substances. The intent of this article is to review structural aspects of the clinical substrate that impact bond formation at the adhesive/dentin interface; to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface.     

Circle Of Life Cancer Education: Giving Voice to American Indian and Alaska Native Communities

The Circle Of Life (COL) was first developed in 1991 as a breast health program through a partnership between the American Cancer Society and a committee of lay and professional volunteers in Oklahoma, with representation from Oklahoma American Indian tribal communities. In 2008, The Society was awarded funding from the Centers for Disease Control and Prevention to expand and enhance COL. Since then, The Society has engaged a variety of tribal health and education leaders and Society staff to comprise a COL advisory workgroup. The workgroup’s mission was to make recommendations and provide guidance in the revision of COL. Four cultural values emerged from the engagement of the workgroup: (1) the value of visual communication, (2) the value of interconnected generations, (3) the value of storytelling, and (4) the value of experiential learning. These four concepts greatly shaped the revision of the COL educational tools and resources.     

Coarse-grained stochastic processes for microscopic lattice systems

Diverse scientific disciplines ranging from materials science to catalysis to biomolecular dynamics to climate modeling involve nonlinear interactions across a large range of physically significant length scales. Here a class of coarse-grained stochastic processes and corresponding Monte Carlo simulation methods, describing computationally feasible mesoscopic length scales, are derived directly from microscopic lattice systems. It is demonstrated below that the coarse-grained stochastic models can capture large-scale structures while retaining significant microscopic information. The requirement of detailed balance is used as a systematic design principle to guarantee correct noise fluctuations for the coarse-grained model. The coarse-grained stochastic algorithms provide large computational savings without increasing programming complexity or computer time per executive event compared to microscopic Monte Carlo simulations.     

Preoperative assessment as a predictor of mortality and morbidity after lung resection

To refine the functional guidelines for operability for lung resection, we prospectively studied 55 consecutive patients with suspected lung malignancy thought to be surgically resectable. Lung function and exercise capacity were measured preoperatively and at 3 and 12 months postoperatively. Preoperative pulmonary scintigraphy was used to calculate the contribution to overall function by the affected lung or lobe and to predict postoperative lung function. Pneumonectomy was performed in 18 patients, lobectomy in 29, and thoracotomy without resection in six. No surgery was attempted in two patients who were considered functionally inoperable. Cardiopulmonary complications developed in 16 patients within 30 days of surgery, including three deaths. The predictions of postoperative function correlated well with the measured values at 3 months. For FEV1, r = 0.51 in pneumonectomy (p less than 0.05) and 0.89 in lobectomy (p less than 0.001). Predicted postoperative FEV1 (FEV1-ppo), diffusing capacity (DLCO), predicted postoperative DLCO (DLCO-ppo) and exercise-induced arterial O2 desaturation (delta SaO2) were predictive of postoperative complications including death and respiratory failure. In patients who underwent pneumonectomy, the best predictor of death was FEV1-ppo. The predictions were enhanced by expressing the value as a percentage of the predicted normal value (% pred) rather than in absolute units. For the entire surgical group a FEV1-ppo greater than or equal to 40% pred was associated with no postoperative mortality (n = 47), whereas a value less than 40% pred was associated with a 50% mortality (n = 6), suggesting that resection is feasible when FEV1-ppo is greater than or equal to 40% pred.(ABSTRACT TRUNCATED AT 250 WORDS)     

Roux-en-Y Gastric Bypass in an Adolescent Patient with Bardet–Biedl Syndrome,a Monogenic Obesity Disorder

Bardet–Biedl syndrome (BBS) is a rare genetic disorder characterized by a wide range of phenotypic variability and associated with the development of life-threatening obesity. Birth weight tends to be normal, but rapid weight gain begins after the first year, probably due to polyphagia rather than abnormalities in energy metabolism. A morbidly obese 16-year-old male patient with BBS was referred to our institution, after nonsurgical methods of weight control had failed, for surgical treatment of his obesity. His preoperative body mass index (BMI) was 52.28 kg/m² (height, 1.84 m; weight, 177 kg) and was above the 99th centile for age and gender. The patient underwent laparoscopic Roux-en-Y gastric bypass (RYGBP). The postoperative period was uneventful. Three and a half years after the operation, the patient's weight has decreased to 118 kg (BMI, 34.85 kg/m²), while significant improvement in his hypertension, hyperuricemia, and mobility has been noted. In our BBS patient, RYGBP proved to be safe and effective; nevertheless, longer follow-up is required to evaluate the weight loss durability and to assess the lasting beneficial effect of surgical intervention on genetically determined co-morbidities.     

Antibiotic Prophylaxis in Primary Hip and Knee Arthroplasty : Comparison Between Cefuroxime and Two Specific Antistaphylococcal Agents

This is a prospective randomized study comparing cefuroxime to 2 antistaphylococal agents (fusidic acid and vancomycin), for prophylaxis in total hip arthroplasty (THA) and total knee arthroplasty (TKA) in an institute, where methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) prevalence exceeds 25% of orthopedic infections. There were 3 patient groups. Group A included the patients who received cefuroxime, group B those who received fusidic acid, and group C those who received vancomycin. Patients were evaluated for the presence of superficial and/or deep infection at the surgical site. Statistical analysis did not reveal any substantial difference between the 3 groups. We do not recommend the use of specific antistaphylococcal agents for prophylactic use in primary THA and TKA, even in institution where MRSA and MRSE exceed 25% of orthopedic infections.     

Arterial and bronchoalveolar lavage fluid endothelin-1 concentration in asthma

Endothelins are a family of peptide mediators that have a number of biological properties, including the ability to act as bronchoconstrictors and vasoconstrictors of isolated airways and vessels. Endothelin-1 (ET-1) is the more potent peptide compared with the other two peptides of the family. To examine a possible involvement of ET- 1 in the pathogenesis of asthma, we measured arterial ET-1 levels in 11 patients with atopic asthma during attack and during remission, and in 11 healthy control subjects. We also performed fiberoptic bonchoscopy and bronchoalveolar lavage (BAL) to measure ET-1 levels in the 11 asthmatic patients during remission, and in the 11 healthy control subjects. ET-1 concentrations in arterial blood and in BAL were measured by a radioimmunoassay method. Arterial ET-1 levels were very significantly higher in asthma attack (3.67 +/- 0.51 pg ml(-1)) and in asthma remission (2.65 +/- 10.62 pg ml(-1)) compared with those of the healthy controls (1.37 +/- 0.14 pg ml(-1)) (P < 0.001). Arterial ET-1 levels were also very significantly higher during asthma attack compared with those in asthma remission (P < 0.001). BAL ET-1 levels were significantly higher in asthma remission (0.73 +/- 0.53 pmol g(-1)) compared with those of the healthy controls (0.16 +/- 0.02 pmol g(-1)) (P < 0.05). No correlation was observed between arterial and BAL ET-1 levels, PaO2 and peak expiratory flow rate (PEFR). These data are consistent with the hypothesis that ET-1 contributes to the pathophysiology of asthma. However, it is likely that the true importance of this vasoconstrictor peptide will only be revealed by pharmacological studies with specific receptor antagonists.     

Cytoreductive Surgery and Intraoperative Hyperthermic Intraperitoneal Chemotherapy with Paclitaxel: A Clinical and Pharmacokinetic Study

Background Intraperitoneal chemotherapy has been recommended as a treatment option for ovarian cancer with peritoneal dissemination. Although its treatment duration is significantly shorter, intraoperative hyperthermic intraperitoneal perfusion chemotherapy (HIPEC) has several advantages over simple intraperitoneal instillation chemotherapy. While platinum compounds have usually been used, only a few have administered paclitaxel during HIPEC. Its large molecular weight suggests a much more favorable pharmacokinetic profile than that of platinum compounds. The pharmacokinetics of paclitaxel during and after HIPEC have not been studied before. Methods Thirteen women, mainly with ovarian cancer, underwent cytoreductive surgery and HIPEC with 175 mg/m² paclitaxel for 2 h. Morbidity was noted. Peritoneal fluid samples and blood samples were harvested during and until 5 days after HIPEC for pharmacokinetic study in ten patients. Results No treatment-related mortality was noted. Overall morbidity was 38% (two wound infections, one deep venous thrombosis, two grade 1 thrombopenia, one grade 2 neutropenia, and one grade 3 pancytopenia). Mean maximal intraperitoneal paclitaxel concentration was 101 mg/L, which was an average of 1178 times higher than the peak plasma levels. The peritoneal fluid versus plasma AUC ratio was 1462 for the 2-h HIPEC duration and 366 for the total 5-day study period. Cytotoxic drug concentrations were detected in peritoneal fluid for a mean period of 2.7 days, despite drainage of the drug solution after 2 h of treatment. Conclusions HIPEC with paclitaxel following cytoreductive surgery is feasible, relatively safe, and associated with a highly favorable pharmacokinetic profile, despite its short treatment duration. Larger studies with a more homogenous patient cohort and adequate follow-up should be performed to demonstrate its efficacy.