Response to Letter Regarding Article, “Quantification of Incomplete Revascularization and Its Association With Five-Year Mortality in the Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) Trial: Validation of the Re
Transforming growth factor β (TGF-β) coordinates a number of biological events important in normal and pathophysiological growth. In this study, deletion and substitution mutations were used to identify receptor motifs modulating TGF-β receptor activity. Initial experiments indicated that a COOH-terminal sequence between amino acids 482–491 in the kinase domain of the type I receptor was required for ligand-induced receptor signaling and down-regulation. These 10 amino acids are highly conserved in mammalian, Xenopus, andDrosophila type I receptors. Although mutation or deletion of the region (referred to as the NANDOR BOX, for nonactivating non–down-regulating) abolishes TGF-β–dependent mitogenesis, transcriptional activity, type I receptor phosphorylation, and down-regulation in mesenchymal cultures, adjacent mutations also within the kinase domain are without effect. Moreover, a kinase-defective type I receptor can functionally complement a mutant BOX expressing type I receptor, documenting that when the BOX mutant is activated, it has kinase activity. These results indicate that the sequence between 482 and 491 in the type I receptor provides a critical function regulating activation of the TGF-β receptor complex.
Mechanisms of Transforming Growth Factor-β Receptor Endocytosis and Intracellular Sorting Differ between Fibroblasts and Epithelial Cells
Transforming growth factor-βs (TGF-β) are multifunctional proteins capable of either stimulating or inhibiting mitosis, depending on the cell type. These diverse cellular responses are caused by stimulating a single receptor complex composed of type I and type II receptors. Using a chimeric receptor model where the granulocyte/monocyte colony-stimulating factor receptor ligand binding domains are fused to the transmembrane and cytoplasmic signaling domains of the TGF-β type I and II receptors, we wished to describe the role(s) of specific amino acid residues in regulating ligand-mediated endocytosis and signaling in fibroblasts and epithelial cells. Specific point mutations were introduced at Y182, T200, and Y249 of the type I receptor and K277 and P525 of the type II receptor. Mutation of either Y182 or Y249, residues within two putative consensus tyrosine-based internalization motifs, had no effect on endocytosis or signaling. This is in contrast to mutation of T200 to valine, which resulted in ablation of signaling in both cell types, while only abolishing receptor down-regulation in fibroblasts. Moreover, in the absence of ligand, both fibroblasts and epithelial cells constitutively internalize and recycle the TGF-β receptor complex back to the plasma membrane. The data indicate fundamental differences between mesenchymal and epithelial cells in endocytic sorting and suggest that ligand binding diverts heteromeric receptors from the default recycling pool to a pathway mediating receptor down-regulation and signaling.
Quantification of Incomplete Revascularization and its Association With Five-Year Mortality in the Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) Trial Validation of the Residual SYNTAX Score
Background— The residual Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) Score is an objective measure of the degree and complexity of residual stenosis after percutaneous coronary intervention (PCI). Methods and Results— In the randomized PCI cohort of the SYNTAX Trial (n=903), the baseline and residual SYNTAX Scores were calculated. Subjects with a residual SYNTAX Score of 0 were defined as having undergone complete revascularization (CR), and a residual SYNTAX Score >0 as incomplete revascularization (ICR). Five-year clinical outcomes were stratified by CR and ICR (tertiles of the residual SYNTAX Score: >0–4, >4–8, and >8). In the PCI cohort, the mean baseline and residual SYNTAX Scores were 28.4±11.5 and 4.5±6.9, respectively. The mean Δ SYNTAX Score (representative of the burden of disease removed by PCI) was 23.8±10.9. The residual SYNTAX Score was distributed as follows: CR, 0 (n=386, 42.7%); ICR, >0 to 4 (n=184, 20.4%), >4 to 8 (n=167, 18.5%), >8 (n=153, 16.9%). A progressively higher residual SYNTAX Score was shown to be a surrogate marker of increasing clinical comorbidity and anatomic complexity. Subjects with CR or residual SYNTAX Scores ≤8 had comparable 5-year mortality (CR, 8.5%; residual SYNTAX Score >0–4, 8.7%; >4–8, 11.4%; P =0.60). A residual SYNTAX Score >8 was associated with 35.3% all-cause mortality at 5-years ( P <0.001). Stratified analyses in the predefined medical treated diabetic and left main subgroups yielded similar results. Conclusions— The residual SYNTAX Score was shown to be a powerful indicator of 5-year mortality in the SYNTAX Trial. The residual SYNTAX Score may aid in determining a reasonable level of revascularization. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00114972.
Evaluation of the Abbott HBV RUO Sequencing Assay Combined with Laboratory-Modified Interpretive Software
ABSTRACTThe Abbott HBV RUO Sequencing assay (Abbott Molecular Inc., Des Plaines, IL), which combines automated sample processing, real-time PCR, and bidirectional DNA sequencing, was evaluated for detection of nucleos(t)ide analogue (NA) resistance-associated mutations located in the hepatitis B virus (HBV) polymerase (Pol) gene. Interpretive software from the assay manufacturer was modified to allow interrogation of the overlapping HBV surface (S) gene sequence for HBV genotype determination and detection of immune escape mutations. Analytical sensitivity (detection and sequencing) of the assay was determined to be 103.9 IU/ml (95% confidence interval [CI], 80.0 to 173.3) for HBV genotype A. Testing of commercially available HBV genotype panels consisting of 23 individual members yielded complete agreement between expected results and results obtained from the laboratory-developed HBV genotype library. Excellent specificity was observed among clinical specimens with serologic or molecular markers for various unrelated blood-borne viruses (n= 6) and sera obtained from healthy, HBV-negative blood donors (n= 20). Retrospectively selected clinical specimens tested by a commercial reference laboratory HBV sequencing assay (n= 54) or the TrugeneHBVGenotyping kit (n= 7) and the Abbott HBV RUO Sequencing assay showed minor differences in detection and reporting of NA resistance-associated mutations in 7 of 61 (11.5%) specimens but complete agreement of genotype results. The Abbott HBV RUO Sequencing assay provided a convenient and efficient assay workflow suitable for routine clinical laboratory use, with the flexibility to be modified for customized detection of NA resistance-associated mutations, HBV genotype determination, and detection of immune escape mutations from a single contiguous HBV sequence.
CT Grading of Lung Disease in Lymphangioleiomyomatosis
Abstract Background Surgical planning and local-regional treatment of breast cancer relies on accurate assessment of disease extent including the primary tumor size and the presence/absence of multiple tumor foci. As a staging modality for breast cancer, MRI has shown high sensitivity for detection of additional foci of diseases within the index breast. However, the impact of preoperative breast MRI on reducing re-excision rates and improving local control is less clear. Data from the COMICE trial in the UK suggested that routine use of pre-operative breast MRI did not alter rates of re-excision; however issues have been raised about the lack of quality standards for the MR imaging that may have resulted in the negative results of this trial. Retrospective data suggest that local recurrence is not impacted by use of breast MRI. In concert with data showing no improvement in clinical outcomes of breast cancer patients, concerns have been raised that routine use of preoperative breast MRI is associated with increased rates of mastectomy and delays to surgery. Therefore, the application of MRI for preoperative surgical staging remains controversial. In order to address this ongoing controversy, a joint effort has been launched by ACOSOG and ACRIN for a prospective clinical trial focused on evaluating the impact of preoperative breast MRI on clinically relevant patient outcomes. An important part of this collaboration is implementation of standards of how MRI findings should be clinically managed and used to direct localization methods and surgical planning, thereby creating guidelines for subsequent patient intervention. Trial design/eligibility criteria: A prospective multicenter trial will include women eligible for BCT by standard criteria and randomized between current standard of care, clinical examination and mammography (+/− ultrasound) and the same plus preoperative breast MRI. The study will focus on women at the highest risk of local recurrence: ER/PR/HER-2 negative (triple negative) and HER-2 amplified breast cancers. Specific aims: To compare the rates of local recurrence following breast conserving therapy in a cohort randomized to preoperative staging with mammography or mammography plus breast MRI. Additionally, a comparison of rates of re-operation, time to local recurrence, survival outcomes, contralateral breast cancer rates, rates of multicentric disease and other secondary aims will be performed. Costs and quality of life measures will also be investigated. Statistical methods: A stratified logrank test and Cox partial likelihood score test will be used to assess whether the distribution of LR times differs with respect to diagnostic work-up approach having adjusted for tumor stage. Cox modeling with the Cox partial likelihood score test will be used to examine the strength of association between these time to event distributions and such additional potential prognostic factors as menopausal status, chemotherapy, radiation therapy, ER, PR, number of positive lymph nodes, HER-2/neu expression, Nottingham grade, and Ki-67 expression. Target Accrual: 556 patients Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-05-06.
Multisystem neuronal degeneration, hepatosplenomegaly, and adrenocortical deficiency associated with reduced tissue arachidonic acid
New vibration pulses are proposed to increase the power of shear waves induced by ultrasound radiation force in a tissue region with a preferred spectral distribution. The new pulses are sparsely sampled from an orthogonal frequency wave composed of several sinusoidal signals. Those sinusoidal signals have different frequencies and are orthogonal to each other. The phase and amplitude of each sinusoidal signal are adjusted to control the shape of the orthogonal frequency wave. Amplitude of the sinusoidal signal is increased as its frequency increases to compensate for higher loss at higher frequency in the tissue region. The new vibration pulses and detection pulses can be interleaved for array transducer applications. The experimental results show that the new vibration pulses significantly increases induced tissue vibration with the same peak ultrasound intensity, compared with the binary vibration pulses.