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.     

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.     

Scrotal skin ulcer in a patient with a previous tonsillectomy because of natural killer cell lymphoma

The CD56+ lymphomas are a recently characterized high-grade malignancy of putative natural killer cell origin. They are mostly localized to the nasal areas but show a propensity to spread to or recur in the skin. We describe a unique case of CD56+ natural killer lymphoma that recurred in scrotal skin in a patient 8 years after an initial limited resection. Although this case was unusual in showing a prolonged period of apparent remission, it illustrated a characteristic clinicopathologic behavior of this rare tumor.     

Src can regulate carboxy terminal interactions with AFAP-110, which influence self-association, cell localization and actin filament integrity

The SH2 and SH3 binding partner AFAP-110 is a tyrosine phosphorylated substrate of Src. AFAP-110 has been hypothesized to link Src to actin filaments, which may contribute to the effects of Src upon actin filament integrity. However, it has been unclear what effect activated Src (Src527F) has upon AFAP-110 structure or function and whether AFAP-110 plays a role in actin filament integrity. We report here that the carboxy terminal 127 amino acids of AFAP-110 are comprised of an alpha-helical region that contains a leucine zipper motif. This indicated the potential of AFAP-110 to self-associate. Expression of the carboxy terminus as a fusion protein (GST-cterm) will permit affinity absorption of cellular AFAP-110. The integrity of the alpha-helical leucine zipper motif in GST-cterm is required for affinity absorption, but binding is not due to a classical leucine zipper interaction. Co-expression of Src527F, unlike cSrc, will abrogate affinity absorption of AFAP-110 with GST-cterm. These data indicate that Src527F has affected a change in the carboxy terminal structure that renders AFAP-110 unavailable for affinity absorption. Superose chromatography demonstrate that AFAP-110 will fractionate as a monomer or multimer, indicating AFAP-110 can be detected in a self-associated form in cell lysates. Co-expression of Src527F resulted in AFAP-110 fractionating with a molecular weight that predicts only a multimeric population. Deletional mutagenesis also indicate a biological role for the carboxy terminus in cellular localization and actin filament integrity. Deletion of the entire carboxy terminal alpha-helix (84 amino acids) will not permit AFAP-110 to efficiently colocalize with actin filaments or the cell membrane. Deletion of only the leucine zipper region of the carboxy terminal alpha-helix (44 amino acids) from AFAP-110 (AFAPAdeltazip) demonstrate that both AFAPdeltalzip and actin filaments are repositioned into rosette-like structures, similar to the effects of Src527F, while co-expression of AFAP-110 with cSrc will not affect actin filaments. These data indicate that AFAP-110 can play an important role in modulating actin filament integrity through carboxy terminal interactions that can be affected by Src527F.