Temperature rise during polymerization of light-activated resin composites

There has been a steady rise in the use of resin-based composites in the restoration of large posterior cavities. Visible light-activated materials have come to dominate the market for direct posterior composites because of the convenience offered to the operator by their command set nature. Manufacturers have produced more powerful light-activation units in response to concerns over inadequate depth of cure. However, some authors have warned of the danger to the dental pulp induced by excessive heat generated during polymerization. Variables governing heat generation include output intensity of the light-activation unit, quality of light filter, irradiation time, material composition and material surface-light guide exit window distance, residual dentine thickness and cavity dimensions. This in vitro study assessed the relative influence of some of these factors under controlled conditions. The findings suggest that minimum irradiation times should be used when curing bonding agents in unlined cavities where residual dentine thickness is limited and high output intensity light-activation units are employed. Material composition is identified as an important variable in determining the magnitude of the temperature rise.     

Three-dimensional respiratory-gated MR angiography of coronary arteries: comparison with conventional coronary angiography

OBJECTIVE: MR coronary angiography is most often performed using two-dimensional techniques. Although three-dimensional (3D) acquisitions do have important advantages, they take too long for a single breath-hold and are thus susceptible to respiratory motion artifacts. The purpose of this study was to investigate the accuracy of a unique respiratory-gated 3D MR angiographic technique in identifying the proximal coronary arteries in patients suspected of having coronary artery disease. In addition, we investigated the capability of this technique to detect proximal stenoses. SUBJECTS AND METHODS: We performed a prospective blinded study in 20 patients who were referred for conventional coronary angiography. A cardiac-gated 3D gradient-echo sequence with fat suppression was used. Retrospective respiratory gating was performed using navigator echoes of the diaphragm position. Using multiplanar reformatting, two independent readers blindly analyzed the data sets for visualization of major coronary arteries, lengths of imaged segments, and detection of significant stenoses (> 50% occlusion of the luminal diameter by conventional angiography). RESULTS: Seventy-seven of 80 (96%) coronary arteries were positively identified. In one patient, an anomalous coronary anatomy was readily identified and confirmed by conventional angiography. The average lengths of the imaged segments of the right, left main, left anterior descending, and left circumflex coronary arteries were 58 +/- 13 mm, 9 +/- 5 mm, 59 +/- 16 mm, and 24 +/- 10 mm, respectively. Overall sensitivity for the detection of stenoses was low (38%), with a specificity of 95%. Interobserver agreement was 0.92, with a kappa value of 0.65. CONCLUSION: Respiratory-gated 3D MR angiography allows accurate identification of proximal coronary arteries and may be valuable for 3D imaging of coronary anomalies. Further technical improvements are required to enhance the value of the technique in detecting stenoses.     

Phosphorous and proton spectroscopy in relation to near incarceration and incarceration of the human brain

The yeast gene, YTA10, encodes a member of a novel family of putative ATPases. Yta10p, as deduced from the nucleotide sequence, is 761 amino acids in length (predicted molecular mass 84.5 kDa). The amino acid sequence of Yta10p exhibits high similarity to two other yeast proteins, Yta11 and Yta12, and to E. coli FtsH. Several features of Yta10p are compatible with its localization in mitochondria. We report here that Yta10p is a yeast mitochondrial protein and that import is dependent on a membrane potential and accompanied by processing to a protein of approximately 73 kDa. Disruption of YTA10 leads to a nuclear petite phenotype and to a loss of respiratory competence, as shown by spectrophotometric measurement of the activities of respiratory complexes I-III and IV, respectively. These findings together with the high similarity of Yta10p to several ATP-dependent proteases suggest that Yta10p is a mitochondrial component involved, directly or indirectly, in the correct assembly and/or maintenance of active respiratory complexes.     

Site of peptic ulcer. comparison of hydrochloric acid output, pepsinogen and gastrin serum levels

BACKGROUND/AIMS: Basal (BAO) and maximum (PAO) hydrochloric acid output after Histalog stimulation, basal pepsinogen (SPL-B), at 60 (SPL-60) and at 90 minutes (SPL-90), and basal gastrin (BG) levels were measured and compared in different gastric (GU) and duodenal (DU) ulcer sites. MATERIAL AND METHODS: Fifty nine patients with peptic ulcer were grouped according to Johnson's classification for gastric ulcers: type I (15), type II (16) type III (12) GU and (16) DU. Fifteen normal subjects were studied as controls. RESULTS: The BAO was greater in the DU than in the control or GU groups. No significant difference was noted in the production of hydrochloric acid after stimulation with Histalog. The SPL-B, at 60 and at 90 minutes was higher in type II GU than in the DU group and controls. The SPL-60 was higher in type II GU patients than in type III GU. Basal gastrin was higher in group DU and types II and III GU compared to the type I GU patients and controls. CONCLUSION: The topographic criteria for differentiating peptic ulcers has low discrimination capacity based on comparison of mean values of HCl acid production, pepsinogen and gastrin serum levels both basal and after stimulation with Histalog due to heterogeneity of these variables in group studies. In these studies, peptic ulcers from different sites should not be grouped as distinct entities except for type II gastric ulcers.     

Fine needle aspiration cytology and histopathology of crystalloids in a cystic lesion of parotid salivary gland

OBJECTIVE: The purpose of this study was to describe the CT findings of pancreatic lipomas in four patients. CONCLUSION: In all four cases, the lipoma was revealed incidentally on CT scans obtained for other reasons. CT scans were diagnostic, showing well-circumscribed masses within the pancreas composed almost entirely of fat, with a few scattered vessels or septa or both, which ranged in size from 1.4 x 2.0 cm to 4.5 x 5.3 cm in the axial plane. Pancreatic lipomas are rare, usually incidental tumors and, as with lipomas found elsewhere in the body, conservative management is often indicated.     

Tau self-association: stabilization with a chemical cross-linker and modulation by phosphorylation and oxidation state

tau is a major component of paired helical filaments found in the neurofibrillary tangles of Alzheimer's diseased brain. However, the mechanism or mechanisms responsible for the association of tau to form these aggregates remains unknown. In this study, the role of intermolecular disulfide bonds in the formation of higher order oligomers of bovine tau and the human recombinant tau isoform T3 was examined using the chemical cross-linking agent disuccinimidylsuberate (DSS). In addition, the role of phosphorylation and oxidation state on the in vitro self-association of tau was studied using this experimental model. Stabilization of tau-tau interactions with DSS indicated that intermolecular disulfide bonds probably play a predominant role in dimer formation, but the formation of higher order oligomers of tau cannot be attributed to these bonds alone. tau-tau interactions were significantly decreased either by blocking Cys residues or by exposing the tau to a reducing (nitrogen and dithiothreitol), instead of an oxidizing, environment. tau self-association was also significantly decreased by prior phosphorylation with calcium/calmodulin-dependent protein kinase II. Phosphorylation by cyclic AMP-dependent protein kinase or dephosphorylation by alkaline phosphatase did not alter tau self-assembly. These data suggest a role for several factors that may modulate tau self-association in vivo.     

Association of MSX1 and TGFB3 with nonsyndromic clefting in humans

Nonsyndromic cleft lip with or without cleft palate (CL/P) and nonsyndromic cleft palate only (CPO) are common congenital anomalies with significant medical, psychological, social, and economic ramifications. Both CL/P and CPO are examples of complex genetic traits. There exists sufficient evidence to hypothesize that disease loci for CL/P and CPO can be identified by a candidate-gene linkage-disequilibrium (LD) strategy. Candidate genes for clefting, including TGFA, BCL3, DLX2, MSX1, and TGFB3, were screened for LD with either CL/P or CPO in a predominantly Caucasian population, with both case-control- and nuclear-family-based approaches. Previously reported LD for TGFA with both CL/P and CPO could not be confirmed, except in CL/P patients with a positive family history. Also, in contrast to previous studies, no LD was found between BCL3 and either CL/P or CPO. Significant LD was found between CL/P and both MSX1 and TGFB3 and between CPO and MSX1, suggesting that these genes are involved in the pathogenesis of clefting. In addition, a mutation search in the genes DLX2, MSX1, and TGFB3 was performed in 69 CPO patients and in a subset of the CL/P patients. No common mutations were found in the coding regions of these genes; however, several rare variants of MSX1 and TGFB3 were found that may alter the latters' normal function. These results form the basis for future research, including (a) mutation searches in the MSX1 and TGFB3 genes in Caucasian CL/P patients and (b) extension of the search for MSX1 mutations in CPO patients to the noncoding regions.     

Wasp and bee venom allergy

To diagnose insect venom allergy a good patient history is important. Allergological tests (skin test, specific IgE titre) confirm the diagnosis. Patients are advised on preventive measures (e.g. with respect to clothing and use of perfume). They are also instructed on medical treatment (antihistaminics, epinephrine) in case they are stung again. In patients having had a serious systemic reaction immunotherapy should be considered. Immunotherapy leads to complete protection in more than 98% of patients with wasp (yellow jacket) venom allergy and in 75-80% of patients with bee venom allergy. Serious adverse reactions to immunotherapy are rare. Immunotherapy lasts at least 3 to 5 years. After cessation of immunotherapy the frequency of systemic reactions to the sting of a wasp or bee is in the range of 5-15%. There are insufficient data on the long-term effect of immunotherapy.