Caraterização biomecânica de implantes com diferentes conexões e materiais

Objetivo: Caraterizar a biomecânica de implantes dentários com diferentes macrogeometrias e composições estruturais, através de um estudo de fadiga in vitro, em que foram comparadas duas conexões internas distintas e avaliado o seu desempenho mecânico, tendo um implante de peça única como controlo. Materiais e métodos: Foram avaliados 3 implantes – 1 de uma peça (100% dióxido de zircónio) e 2 de duas peças (liga titânio-zircónia) – entre os de duas peças, um com uma conexão cónica 8º e um octógono interno, e outro com uma conexão cónica de 7º. Os implantes foram montados num bloco de osso artificial customizado e submetidos a 120.000 cargas cíclicas axiais, através de uma máquina universal de ensaios mecânicos, que permitiu simular 6 meses de mastigação humana. Foram definidos como parâmetros físicos: Fmáx = 272 N, Fmin = 27,2 N, A = 122 N, R = 0,1, F = 5 Hz. Resultados: Todos os três ensaios foram concluídos com sucesso, sem haver fratura ou desaparafusamento de nenhum componente do sistema implantar, durante ou depois dos testes. O deslocamento para o implante cerâmico de uma peça foi o menor dos três. A análise estatística revelou uma diferença estatisticamente significativa entre os parâmetros testados para os três implantes, rejeitando-se as hipóteses nulas do estudo. Conclusão: Este estudo permite concluir que os sistemas implantares usados são mecanicamente estáveis, especialmente a sua resistência à fadiga. Os implantes com conexões internas são uma opção de reabilitação previsível e o implante de conexão cónica 7º relevou ter um comportamento semelhante ao implante de peça única.Aim: To characterize the biomechanics of dental implants with different macrogeometry and structural composition, through a load fatigue in vitro test, where the performance of two distinct internal implant-abutment connections were compared, with a one- piece implant as a control group. Methods: A total of 3 implants were assessed – 1 one-piece implant (100% zirconium dioxide) and 2 two-piece (titanium-zirconia alloy) – within the two-piece implants, one had a conical connection of 8º and an internal octagon, and the other had a 7º conical connection. The implants were placed in customized artificial bone and under 120.000 axial cyclic loads, using a universal fatigue testing machine, that simulated 6 months of oral service. The physical parameters were defined as: 272 N maximum load, 27,2 N minimum load, 122 N amplitude, R = 0,1 and 5 Hz frequency. Results: All 3 implants were tested and none of them suffered fracture or unscrewing of components during or after the tests. The displacement was lowest on the one-piece ceramic implant. Statistical analysis showed a significant difference for all the parameters tested on the 3 implants, so the null hypothesis was rejected. Conclusion: The implants used in this study have mechanical stability and flexural strength. The implants with internal connections are a predictable prosthodontic option. The 7º conical connection implant has a similar mechanical behavior as the one-piece implant

Comparison of postnatal catch-up growth according to definitions of small for gestational age infants

PurposeSmall for gestational age (SGA) is confusingly defined as birth weight (BW) either below 3rd percentile or 10th percentile for infants. This study aimed to compare postnatal catch-up growth between SGA groups according to different definitions.MethodsData of 129 infants born with BW below the 10th percentile and admitted to Korea University Anam Hospital and Ansan Hospital were retrospectively reviewed. Height and weight were measured at 6, 12, and 24 months. Results were compared between group A (BW: <3rd percentile) and group B (BW: 3rd–10th percentile).ResultsGroup A included 66 infants and group B included 63. At age 6 months (n=122), 62.9% of group A and 71.7% (P=0.303) of group B showed catch-up growth in weight. At 6 months (n=69), 55.9% of group A and 80.0% of group B (P<0.05) showed catch-up growth in height. At 12 months (n=106), 58.5% of group A, and 75.5% (P=0.062) of group B showed catch-up growth in weight. At 12 months (n=75), 52.8% of group A and 64.1% of group B (P=0.320) showed catch-up growth in height. Up to age 24 months, 66.7%/80.0% in group A and 63.6%/80.0% in group B showed catch-up growth in weight/height.ConclusionDespite different definitions, there were no significant differences between the two SGA groups in postnatal catch-up growth up to age 24 months, except for height at 6 months. Compared to infants with appropriate catch-up growth, low gestational age and BW were risk factors for failed catch-up growth at 6 months

Obesity and incidence of diabetes: Effect of absence of metabolic syndrome, insulin resistance, inflammation and fatty liver

Background and aimsObesity is frequently associated with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR), inflammation and metabolic syndrome (MetS), all of which increase the risk of type 2 diabetes (T2DM). However, the role of these risk factors in mediating the effect of obesity remains unclear. We investigated the association between obesity and T2DM in the absence and presence of NAFLD, IR, inflammation and MetS components.Methods29,836 obese subjects without diabetes were studied in a Korean health screening program. Obesity was defined by the appropriate ethnic-specific body mass index (BMI) threshold ≥25 kg/m2. Hazard ratios (HRs and 95% confidence intervals, CIs) for incident T2DM were estimated for the group with no hypertension, dyslipidemia, impaired fasting glucose, fatty liver, IR, or inflammation (n = 1717), compared to the reference group, with one or more of these factors (n = 19,757).ResultsMean (SD) age at baseline was 37 (7) years and 1200 incident cases of diabetes occurred. Crude T2D incidence was 12.6/10,000 person-years in the group without metabolic abnormality and 143/10,000 person-years in the reference group. HR (95% CIs) for incident diabetes was 0.13 (0.06, 0.33) in the group without metabolic abnormality.ConclusionsObese subjects without components of the metabolic syndrome, IR, fatty liver and inflammation have an approximately 11-fold lower risk of incident type 2 diabetes than obese subjects who have these risk factors. These simple factors could be used to target limited resources in high risk obese subjects in the prevention of diabetes

Transcatheter Closure of Fenestration with Detachable Coils After the Fontan Operation

We report our experience in 13 patients who underwent transcatheter closure of Fontan fenestration with the Cook® detachable coils. These patients underwent the extracardiac type Fontan operation with a short conduit fenestration (n=7) or lateral tunnel type with a punch-hole fenestration (n=6). Fenestration closure was done at the mean age of 5.1±2.4 yr, average of 32 months after the Fontan operation. We used one to three coils depending on the fenestration type, size, and residual shunt. Aortic oxygen saturations increased by an average of 5.4 (2-9)% and mean pressures in the Fontan circuit increased by an average of 2.1 (0-6) mmHg. During fol-low-up (median of 23 months), five patients (4 in extracardiac, 1 in lateral tunnel) had complete occlusion of the fenestration on echocardiography. There was no immediate or late complication. Transcatheter closure of fenestration in Fontan operation using the Cook® detachable coil is a safe and feasible technique. However, the coil was ineffective for closure of a punch-hole fenestration in the lateral tunnel type operation. In the conduit type fenestration, some modification of fenestration method instead of a short conduit for coil closure or use of new device is necessary to increase complete closure rate

The Clinical Usefulness of the SD Bioline Influenza Antigen Test® for Detecting the 2009 Influenza A (H1N1) Virus

Though the 2009 worldwide influenza A (H1N1) pandemic has been declared to have ended, the influenza virus is expected to continue to circulate from some years as a seasonal influenza. A rapid antigen test (RAT) can aid in rapid diagnosis and allow for early antiviral treatment. We evaluated the clinical usefulness of RAT using SD Bioline Influenza Antigen Test® kit to detect the influenza virus, considering various factors. From August 1, 2009 to October 10, 2009, a total of 938 patients who visited the outpatient clinic at Korea University Guro Hospital with influenza-like illnesses were enrolled in the study. Throat or nasopharyngeal swab specimens were obtained from each of the patients. Using these specimens, we evaluated the influenza detection rate by rapid antigen test based on the real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) method. In comparison with rRT-PCR, the sensitivity and specificity of the RAT were 44.0% and 99.9%, respectively. The cyclic threshold values of RAT negative specimens were higher than RAT positive specimens (30.1±3.1 vs. 28.3±3.9, p=0.031). The sensitivity of the RAT kit was higher in patients who visited clinics within two days of symptom onset (60.4% vs. 11.1%, p=0.026). The results of this study show that the RAT cannot be recommended for general use in all patients with influenza-like illness because of its low sensitivity. The RAT may be used, only in the settings with limited diagnostic resources, for patients who visit a clinic within two days of symptom onset

Autophagy pathway upregulation in a human iPSC-derived neuronal model of Cohen syndrome with VPS13B missense mutations

Significant clinical symptoms of Cohen syndrome (CS), a rare autosomal recessive disorder, include intellectual disability, facial dysmorphism, postnatal microcephaly, retinal dystrophy, and intermittent neutropenia. CS has been associated with mutations in the VPS13B (vacuolar protein sorting 13 homolog B) gene, which regulates vesicle-mediated protein sorting and transport; however, the cellular mechanism underlying CS pathogenesis in patient-derived neurons remains uncertain. This report states that autophagic vacuoles accumulate in CS fibroblasts and the axonal terminals of CS patient-specific induced pluripotent stem cells (CS iPSC)-derived neurons; additionally, autophagic flux was significantly increased in CS-derived neurons compared to control neurons. VPS13B knockout HeLa cell lines generated using the CRISPR/Cas9 genome editing system showed significant upregulation of autophagic flux, indicating that VSP13B may be associated with autophagy in CS. Transcriptomic analysis focusing on the autophagy pathway revealed that genes associated with autophagosome organization were dysregulated in CS-derived neurons. ATG4C is a mammalian ATG4 paralog and a crucial regulatory component of the autophagosome biogenesis/recycling pathway. ATG4C was significantly upregulated in CS-derived neurons, indicating that autophagy is upregulated in CS neurons. The autophagy pathway in CS neurons may be associated with the pathophysiology exhibited in the neural network of CS patients.This work was supported by National Research Foundation (NRF2017R1D1A3B03030972), the National Honor Scientist Program, the Korea Health Technology R&D Project (HI18C0158), and the Bio & Medical Technology Development Program of the National Research Foundation (NRF) funded by the Ministry of Science & ICT (2017M3A9G7073521) to J.-A L

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Prospective Study of Sex-Specific Adiponectin Changes and Incident Metabolic Syndrome: The ARIRANG Study

We investigated whether changes in adiponectin levels over time predict incident metabolic syndrome (MetS) in a population-based prospective study. In total, 1110 subjects were categorized into four groups according to their sex-specific median baseline adiponectin levels and the change in adiponectin levels at follow-up: low baseline adiponectin and decreased adiponectin during follow-up (LB&amp;DF), low baseline adiponectin and increased adiponectin during follow-up (LB&amp;IF), high baseline adiponectin and decreased adiponectin during follow-up (HB&amp;DF), and high baseline adiponectin and increased adiponectin during follow-up (HB&amp;IF). During the median 2.4-year follow-up period, 180 (16.2%) subjects developed MetS. Compared to the LB&amp;DF group, the fully adjusted hazard ratio (95% confidence interval) for incident MS was the lowest in the HB&amp;IF group (0.33, (0.17&ndash;0.63)), followed by the HB&amp;DF group (0.58, (0.40&ndash;0.84)) and LB&amp;IF group (0.63, (0.41&ndash;0.93)). This phenomenon was more prominent in men than in women. Among the individual MetS components, increased adiponectin levels during follow-up were significantly associated with lower risks of incident low high density lipoprotein (HDL) cholesterol and incident high blood pressure. This finding suggests that a change in adiponectin level, as well as the baseline adiponectin level, might have a clinical role in the development of MetS among men