Effect of wax melting range and investment liquid concentration on the accuracy of a three-quarter crown casting.

STATEMENT OF PROBLEM: Dental casting accuracy is influenced by the setting expansion of investment materials. Although setting expansion can help compensate for casting shrinkage, it cannot be fully realized under a confined wax pattern. Exactly how soft a wax pattern should be to ensure optimum setting expansion has not been determined. PURPOSE: In this study, the relationship between wax characteristics and the casting accuracy of a three-quarter crown was investigated. MATERIAL AND METHODS: Four different wax materials were used: paraffin 135 with a softening temperature of 37.5 degrees C (P38), paraffin 1080 with a softening temperature of 63.5 degrees C, Shofu Red with a softening temperature of 41.5 degrees C, and Shofu Hard with a softening temperature of 51 degrees C. Two mixtures of phosphate-bonded investment were prepared: one with 100% special liquid and another with 75% special liquid plus 25% distilled water. For both, the liquid/powder ratio was 16:100. A type IV gold alloy was cast into a three-quarter crown mold. The discrepancy at 6 locations (1 lingual, 1 mesial, 1 distal, and 3 facial) was measured with a traveling microscope. Five readings were collected. Means and standard deviations were calculated for all data. A 2-way analysis of variance followed by the Student-Newman-Keuls test for multiple comparisons was used to identify significant differences between groups at the 95% confidence level. RESULTS: For the gingival measurement sites (lingual, mesial, and distal), there was no significant difference in cast adaptation when Shofu Hard and paraffin 1080 waxes were used. However, the results with these 2 waxes were different than with Shofu Red and P38. For the 3 facial measurement sites, significantly different measurements were found for each wax; P38 demonstrated the best results. Casting shrinkage was smaller with the use of 100% special liquid. CONCLUSION: Within the limitations of this study, casting shrinkage was affected by the type of wax used and was sensitive to the site at which dimensional measurements were performed. The higher the softening temperature, the larger the casting shrinkage.     

Changes in interarch distance and condylar position related to loss of occlusal support for partially edentulous patients. A pilot study

Changes of interarch distance and condylar position related to loss of the posterior occlusal support were investigated. Five subjects, whose mandibular premolars and molars needed to be restored, were selected. Their experimental prostheses were removed in sequence from the most posterior to anterior. The more the posterior occlusal support decreased, the more the interarch distance in the first molar region decreased. When the occlusal supports of both mandibular molars and premolars were absent, the condylar position moved superio-anteriorly. The occlusal support of the first molar showed a significant role in maintaining the intercuspal and condylar position.     

Experimental device for detecting laryngeal movement during swallowing

It has been reported that swallowing is a rhythmic movement, in which the onset of the oro-pharyngeal stage of swallowing starts from the mylohyoid muscle, followed by movement of the oral and pharyngeal muscles, and reaching the superior esophageal sphincter muscle. This is defined as the oro-pharyngeal stage of swallowing. It has also been reported that along with this movement, the larynx elevates in an antero-superior direction. To investigate the swallowing movement, it would be useful to be able to detect the start of swallowing movements from the body surface. Such a device was designed in this study to investigate the relationships between the onset of laryngeal movement and the EMG initiation of the anterior digastric muscle. Although experimental conditions must be further examined, we were able to record the reproducible movement and the position of larynx using our device provides another tool for studying the swallowing movement.     

Zinc finger protein 804A (ZNF804A) and verbal deficits in individuals with autism

Background

In a genome-wide association study of autism, zinc finger protein 804A (ZNF804A) single nucleotide polymorphisms (SNPs) were found to be nominally associated in verbally deficient individuals with autism. Zinc finger protein 804A copy number variations (CNVs) have also been observed in individuals with autism. In addition, ZNF804A is known to be involved in theory of mind (ToM) tasks, and ToM deficits are deemed responsible for the communication and social challenges faced by individuals with autism. We hypothesized that ZNF804A could be a risk gene for autism.

Methods

We examined the genetic association and CNVs of ZNF804A in 841 families in which 1 or more members had autism. We compared the expression of ZNF804A in the postmortem brains of individuals with autism (n = 8) and controls (n = 13). We also assessed in vitro the effect of ZNF804A silencing on the expression of several genes known to be involved in verbal efficiency and social cognition.

Results

We found that rs7603001 was nominally associated with autism (p = 0.018). The association was stronger (p = 0.008) in the families of individuals with autism who were verbally deficient (n = 761 families). We observed ZNF804A CNVs in 7 verbally deficient boys with autism. In ZNF804A knockdown cells, the expression of synaptosomal-associated protein, 25kDa (SNAP25) was reduced compared with controls (p = 0.009). The expression of ZNF804A (p = 0.009) and SNAP25 (p = 0.009) were reduced in the anterior cingulate gyrus (ACG) of individuals with autism. There was a strong positive correlation between the expression of ZNF804A and SNAP25 in the ACG (p < 0.001).

Limitations

Study limitations include our small sample size of postmortem brains.

Conclusion

Our results suggest that ZNF804A could be a potential candidate gene mediating the intermediate phenotypes associated with verbal traits in individuals with autism.     

Histological analysis of appendices removed during interval appendectomy after conservative management of pediatric patients with acute appendicitis with an inflammatory mass or abscess

Background/purpose

To clarify the role of interval appendectomy (IA) in pediatric patients with acute appendicitis with an appendiceal inflammatory mass or abscess, we histologically analyzed the appendices removed during IA.

Patients and methods

We treated 355 consecutive pediatric patients with acute appendicitis and reviewed the admission charts of patients who started conservative management (CM). The histology of the appendix removed during IA was also examined. The relationships among the clinical features, appendicolith formation at the time of IA and histological findings were analyzed by stepwise regression analyses.

Results

(1) CM was started in 48 patients (13.5 %). Recurrence or a remaining abscess was observed in nine patients (18.8 %). (2) Histopathological changes, particularly foreign body reaction with fibrosis and infiltration of inflammatory cells, were observed in about half of the specimens. (3) In a stepwise regression analysis, the presence of an appendicolith at IA was correlated with an appendicolith at diagnosis, foreign body reaction in the appendix and a decrease in the inflammatory reaction at diagnosis.

Conclusion

More than half the patients had strong histopathological changes in the appendix, suggesting a high possibility of recurrence. The presence of appendicolith formation at IA, which is a risk factor for recurrence, was influenced by the presence of an appendicolith at diagnosis, foreign body reaction in the appendix and the inflammatory status of patients at diagnosis. These clinical findings are indications for IA.     

From the Cover: Salt stress-induced Ca2+ waves are associated with rapid,long-distance root-to-shoot signaling in plants

Their sessile lifestyle means that plants have to be exquisitely sensitive to their environment, integrating many signals to appropriate developmental and physiological responses. Stimuli ranging from wounding and pathogen attack to the distribution of water and nutrients in the soil are frequently presented in a localized manner but responses are often elicited throughout the plant. Such systemic signaling is thought to operate through the redistribution of a host of chemical regulators including peptides, RNAs, ions, metabolites, and hormones. However, there are hints of a much more rapid communication network that has been proposed to involve signals ranging from action and system potentials to reactive oxygen species. We now show that plants also possess a rapid stress signaling system based on Ca²⁺ waves that propagate through the plant at rates of up to ∼400 µm/s. In the case of local salt stress to the Arabidopsis thaliana root, Ca²⁺ wave propagation is channeled through the cortex and endodermal cell layers and this movement is dependent on the vacuolar ion channel TPC1. We also provide evidence that the Ca²⁺ wave/TPC1 system likely elicits systemic molecular responses in target organs and may contribute to whole-plant stress tolerance. These results suggest that, although plants do not have a nervous system, they do possess a sensory network that uses ion fluxes moving through defined cell types to rapidly transmit information between distant sites within the organism.Plants are constantly tailoring their responses to current environmental conditions via a complex array of chemical regulators that integrate developmental and physiological programs across the plant body. Environmental stimuli are often highly localized in nature, but the subsequent plant response is often elicited throughout the entire organism. For example, soil is a highly heterogeneous environment and the root encounters stimuli that are presented in a patchy manner. Thus, factors including dry or waterlogged regions of the soil, variations in the osmotic environment, and stresses such as elevated levels of salt are all likely to be encountered locally by individual root tips, but the information may have to be acted on by the plant as a whole.In animals, long-range signaling to integrate activities across the organism occurs through rapid ionic/membrane potential-driven signaling through the nervous system in addition to operating via long-distance chemical signaling. Plants have also been proposed to possess a rapid, systemic communication network, potentially mediated through signals ranging from changes in membrane potential/ion fluxes (1–3) and levels of reactive oxygen species (ROS) (4, 5) to altered hydraulics in the vasculature (6). Even so, the molecular mechanisms behind rapid, systemic signaling in plants and whether such signals indeed carry regulatory information remains largely unknown. Suggestions that Ca²⁺ channels play a role in signals that occlude sieve tube elements (7), or that mediate systemic electrical signaling (2) in response to remote wounding, highlight Ca²⁺-dependent signaling events as a strong candidate for mediating some of these long-range responses. Similarly, cooling of roots elicits Ca²⁺ increases in the shoot within minutes (8), suggesting systemic signals can elicit Ca²⁺-dependent responses at distal sites within the plant. However, despite extensive characterization of Ca²⁺ signals (reviewed in ref. 9), their roles in a possible plant-wide communication network remain poorly understood. Therefore, to visualize how Ca²⁺ might act in local and systemic signaling, we generated Arabidopsis plants expressing the highly sensitive, GFP-based, cytoplasmic Ca²⁺ sensor YCNano-65 (10). We observed that a range of abiotic stresses including H₂O₂, touch, NaCl, and cold shock triggered Ca²⁺ increases at the point of application. However, NaCl also elicited a Ca²⁺ increase that moved away from the point of stress application. Propagation of this Ca²⁺ increase was associated with subsequent systemic changes in gene expression. We also report that this salt stress-induced long-distance Ca²⁺ wave is dependent on the activity of the ion channel protein Two Pore Channel 1 (TPC1), which also appears to contribute to whole-plant stress tolerance.     

Risk factors for surgical site infection after stoma closure comparison between pursestring wound closure and conventional linear wound closure: Propensity score matching analysis

Purpose

Stoma closure has been associated with a high rate of surgical site infection (SSI) and the optimal skin closure method is still controversial. The aim of this study was to compare the short-term and long-term outcomes between the conventional linear closure (CC) and the persestring closure (PC) using propensity score matching analysis.