Three-dimensional finite element modelling of all-ceramic restorations based on micro-CT

ObjectivesTo describe and apply a method of modelling dental crowns and three-unit fixed partial dentures (FPD) for finite element analyses (FEA) from 3D images obtained using a micro-CT scanner.MethodsA crown and a three-unit fixed partial denture (FPD) made of a ceramic framework (Y-TZP) and veneered with porcelain (VM9) were scanned using an X-ray micro-CT scanner with a pixel size of 6.97 μm. Slice images from both structures were generated at each 0.034 mm and processed by an interactive image control system (Mimics). Different masks of abutments, framework and veneer were extracted using thresholding and region growing tools based on X-ray image brightness and contrast. 3D objects of each model were incorporated into non-manifold assembly and meshed simultaneously. Volume meshes were exported to the FEA software (ABAQUS), and the load-generated stress distribution was analyzed.ResultsFEA models showed great shape resemblance with the structures. The use of non-manifold assembly ensured matching surfaces and coinciding nodes between different structural parts. For the crown model, tensile stresses were concentrated in the internal surface of the core, near to the applied load. For the FPD model, the highest tensile stresses were located in the framework, on the cervical area of connectors and pontic.ConclusionsValid 3D models of dental crown and FPD can be generated by combining micro-CT scanning and Mimics software, emphasizing its importance as design tool in dental research.Clinical significanceThe 3D FEA method described in this work is an important tool to predict the stress distribution, assisting on structural design of dental restorations.     

The microINR portable coagulometer: analytical quality and user-friendliness of a PT (INR) point-of-care instrument

Regular measurement of prothrombin time as an international normalized ratio PT (INR) is mandatory for optimal and safe use of warfarin. Scandinavian evaluation of laboratory equipment for primary health care (SKUP) evaluated the microINR portable coagulometer (microINR^®) (iLine Microsystems S.L., Spain) for measurement of PT (INR). Analytical quality and user-friendliness were evaluated under optimal conditions at an accredited hospital laboratory and at two primary health care centres (PHCCs). Patients were recruited at the outpatient clinic of the Laboratory of Medical Biochemistry, St Olav’s University Hospital, Trondheim, Norway (n?=?98) and from two PHCCs (n?=?88). Venous blood samples were analyzed under optimal conditions on the STA-R^®Evolution with STA-SPA?+?reagent (Stago, France) (Owren method), and the results were compared to capillary measurements on the microINR^®. The imprecision of the microINR^® was 6% (90% CI: 5.3–7.0%) and 6.3% (90% CI: 5.1–8.3) in the outpatient clinic and PHCC2, respectively for INR ≥2.5. The microINR^® did not meet the SKUP quality requirement for imprecision ≤5.0%. For INR <2.5 at PHCC2 and at both levels in PHCC1, CV% was ≤5.0. The accuracy fulfilled the SKUP quality goal in both outpatient clinic and PHCCs. User-friendliness of the operation manual was rated as intermediate, defined by SKUP as neutral ratings assessed as neither good nor bad. Operation facilities was rated unsatisfactory, and time factors satisfactory. In conclusion, quality requirements for imprecision were not met. The SKUP criteria for accuracy was fulfilled both at the hospital and at the PHCCs. The user-friendliness was rated intermediate.     

Mucus as a barrier to lipophilic drugs

Mucus is a complex hydrogel, comprising glycoproteins, lipids, salts, DNA, enzymes and cellular debris, covering many epithelial surfaces in the human body. Once secreted, mucin forms a barrier to protect the underlying tissues against the extracellular environment. Mucus can therefore adversely affect the absorption or action of drugs administered by the oral, pulmonary, vaginal, nasal or other routes. Solubility and lipophilicity are key factors determining drug absorption, as a drug has to be soluble in the body fluids at the site of absorption and must also possess enough lipophilicity to permeate the biological membrane. Evidence has accumulated over the past 40 years indicating that poorly soluble drugs will interact with mucus glycoprotein. Studies of the permeability of native or purified mucous gels are important when it comes to understanding the relative importance of hindered diffusion versus drug binding in mucous layers. This review highlights the current understanding of the drug–mucin interaction and also examines briefly the interaction of polymers and particles with the mucus matrix. While the concept of mucoadhesion was thought to provide an intensified and prolonged contact to mucosal absorption sites, mucopenetrating properties are nowadays being discussed for (nano)particulate carriers to overcome the mucus as a barrier and enhance drug delivery through mucus.     

Novel nanostructured supramolecular hydrogels for the topical delivery of anionic drugs

A bis-imidazolium-based amphiphilic molecule was used to form novel supramolecular gels in ethanol–water mixtures. The proportion of solvents, the concentration of gellant and the temperature are factors that strongly influence the gelling process. The physical gels that are formed comprise entangled fibers of around 100 nm in diameter, able to incorporate anionic drugs, whose morphology varies depending on the drug they incorporate. These hydrogels are soft and therefore optimum for skin application. They show good stability when compared to previously reported gels. Suitable drug release and skin permeation profiles were obtained, and, moreover, they seem to promote the retention of the drug inside the skin. Finally, effective in vivo anti-inflammatory activity was observed, especially with the indomethacin-incorporated gel, which indicates that these supramolecular hydrogels are a good option for the delivery of poor water soluble drugs for the treatment of acute inflammation or other skin diseases.     

Organ donor screening using parallel nucleic acid testing allows assessment of transmission risk and assay results in real time

Expansion of the donor pool may lead to utilization of donors with risk factors for viral infections. Donor laboratory screening relies on serological and nucleic acid testing (NAT). The increased sensitivity of NAT in low prevalence populations may result in false‐positive results (FPR) and may cause unnecessary discard of organs.We developed a screening algorithm to deal, in real time, with potential FPR. Three NAT assays: COBAS AmpliScreen assay (CAS), AmpliPrep Total Nucleic Acid Isolation/CAS, and AmpliPrep/TaqMan assays, were validated and used in parallel for prospective screening of increased‐risk donors (IRD), and the probability of FPR was calculated. The lower limit of detection of this algorithm was 9.79, 21.02, and 4.31 IU/mL for human immunodeficiency virus‐1, hepatitis C virus, and hepatitis B virus, respectively, with an average turn‐around‐time of 7.67 h from sample receipt to result reporting. The probability that a donor is potentially infectious with two NAT concordant results was >90%. NAT screening of 35 IRD within 18 months resulted in transplantation of 102 additional organs that without screening would either not be used or used with restrictions in Australia. Using a parallel testing algorithm, real‐time confirmation of seropositive donors allows use of organs from IRD and safer expansion of the donor pool.     

Altered thermal sensitivity in facial skin in chronic whiplash-associated disorders

There is a close functional relationship between the jaw and neck regions and it has been suggested that trigeminal sensory impairment can follow whiplash injury.Inclusion of manageable routines for valid assessment of the facial sensory capacity is thus needed for comprehensive evaluations of patients exposed to such trauma.The present study investigated facial thermal thresholds in patients with chronic whiplash-associated disorders（WADs）with both a qualitative method and quantitative sensory testing（QST）.Ten women with pain and dysfunction following a whiplash injury were compared to 10 healthy age-matched women.Thermal detection thresholds were assessed by qualitative chair-side testing and by QST according to the method-of-limits.Seven test sites in the facial skin（overlying each trigeminal branch bilaterally,and the midpoint of the chin）were examined.The detection warm and cold thresholds were defined as the mean values of 10 individual thresholds.For the WAD patients,the qualitative assessment demonstrated both reduced and increased sensitivity compared to the healthy,whereas QST systematically showed significantly higher detection thresholds（i.e.,decreased sensitivity）for both cold and warm stimuli.For the individuals who were assessed as having increased sensitivity in the qualitative assessment,the QST displayed either normal or higher thresholds,i.e.,decreased sensitivity.The results suggest that QST is more sensitive for detecting thermal sensory disturbances in the face than a qualitative method.The impaired thermal sensitivity among the patients corroborates the notion of altered thermal detection capacity induced by WAD-related pain.     

奥沙利铂联合替吉奥治疗老年晚期胃癌的临床观察

胃癌是我国常见的恶性肿瘤之一，60％以上发现时已属晚期。虽然手术是治疗胃癌的主要方法，但因晚期胃癌患者的患病时间长、预后差等特点使得其术后易转移复发，尤其是老年患者其机体的耐受能力较差，故治疗仍以保守治疗为主。我们对老年晚期胃癌患者予以奥沙利铂联合替吉奥治疗，取得了满意的疗效，现报告如下。     

RAPTOR gene polymorphism is independently correlated with urothelial cancer susceptibility compared with environmental toxin exposure

IntroductionThere are many established environmental toxins that correlate with urothelial cancer. Genetic variations in phosphoinositide-3 kinase (PI3K)-AKT-mammalian target of rapamycin (mTOR) pathway have also been reported to have association with the risk of urothelial cancer and clinical outcome. The aim of this study is to validate the role of the established RAPTOR gene carrying the risk of urothelial cancer compared with environmental toxin exposure.MethodsThis study included 168 patients with urothelial cancer and 168 patients with voiding problem as normal control. All these patients were above 50 years old. Environmental toxin exposure such as smoking, arsenic, and Chinese herb were defined as regular exposure in usual life. RAPTOR single nucleotide polymorphisms (SNPs) were analyzed by Hardy–Weinberg equilibrium to compare the observed genotype frequencies to the expected genotype frequencies in controls. Pearson's χ² test was used to compare the difference in distribution of categorical variables. Statistical significance was set if p value less than 0.005 in this study.ResultsRAPTOR gene polymorphisms (rs11653499 and rs7212142) were revealed to be significantly associated to the risk of urothelial cancer whether the patients is under environmental toxin exposure or not (both p < 0.001). The predictive effects of urothelial cancer for these two SNPs were both independently significant by multivariate analysis (p < 0.001).ConclusionRAPTOR gene polymorphisms are important SNPs with significantly association with the risk of urothelial cancer in Taiwan. Further researches about raptor-mTOR complex interfering malignant transformation of urothelium is worthy of further investigation.