Citations

Background— Cardiac resynchronization therapy (CRT) is an effective therapy for patients with moderate to severe heart failure and prolonged QRS duration. The purpose of this study was to determine whether reverse left ventricular (LV) remodeling and symptomatic benefit from CRT were sustained at 12 months, and if so, in what proportion of patients this occurred. Methods and Results— Serial Doppler echocardiograms were obtained at baseline and 6 and 12 months after CRT in 228 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Measurements were made of LV end-diastolic (EDV) and end-systolic (ESV) volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E wave) and late (A wave) diastolic filling, and myocardial performance index. At both 6 and 12 months, respectively, CRT was associated with reduced LV EDV ( P <0.0001 and P =0.007) and LV ESV ( P <0.0001 and P <0.0001), improved ejection fraction ( P <0.0001 and P <0.0001), regression of LV mass ( P =0.012 and P <0.0001), and reduced MR ( P <0.0001 and P <0.0001). LV filling time, transmitral E/A ratio, and myocardial performance index all improved at 12 months compared with baseline ( P <0.001, P =0.031, and P <0.0001). Reverse LV remodeling with CRT occurred in more patients at 6 than at 12 months (74% versus 60%, respectively; P <0.05) and was greater in patients with a nonischemic than an ischemic etiology. Conclusions— Reverse LV remodeling and symptom benefit with CRT are sustained at 12 months in patients with New York Heart Association class III/IV heart failure but occur to a lesser degree in patients with an ischemic versus a nonischemic etiology, most likely owing to the inexorable progression of ischemic disease.

Abstract Context: The sodium iodide symporter (NIS) mediates the active iodide uptake in the thyroid gland as well as lactating breast tissue. Recently induction of functional NIS expression was reported in the estrogen receptor-positive human breast cancer cell line MCF-7 by all-trans retinoic acid (atRA) treatment in vitro and in vivo, which might offer the potential to treat breast cancer with radioiodine. Objective: In the current study, we examined the effect of dexamethasone (Dex) on atRA-induced NIS expression and therapeutic efficacy of 131-I in MCF-7 cells. Design: For this purpose, NIS mRNA and protein expression levels in MCF-7 cells were examined by Northern and Western blot analysis after incubation with Dex (10−9 to 10−7m) in the presence of atRA (10−6m) as well as immunostaining using a mouse monoclonal human NIS-specific antibody. In addition, NIS functional activity was measured by iodide uptake and efflux assay, and in vitro cytotoxicity of 131-I was examined by in vitro clonogenic assay. Results: After incubation with Dex in the presence of atRA, NIS mRNA levels in MCF-7 cells were stimulated up to 11-fold in a concentration-dependent manner, whereas NIS protein levels increased up to 16-fold and iodide accumulation was stimulated up to 3- to 4-fold. Furthermore, iodide efflux was modestly decreased after stimulation with Dex in the presence of atRA. Furthermore, in the in vitro clonogenic assay, selective cytotoxicity of 131-I was significantly increased from approximately 17% in MCF-7 cells treated with atRA alone to 80% in MCF-7 cells treated with Dex in the presence of atRA. Conclusion: Treatment with Dex in the presence of atRA significantly increases functional NIS expression levels in addition to inhibiting iodide efflux, resulting in an enhanced selective killing effect of 131-I in MCF-7 breast cancer cells.

Gentamicin is a widely used ototoxic agent. In this study, we shed light on the mechanisms underlying gentamicin-induced hearing loss. More importantly, we demonstrate in vivo and in vitro the effectiveness of a strategy for preventing drug-induced hearing loss using l -carnitine (LCAR), a safe micronutrient that plays a key role in energy metabolism and detoxification [Rebouche, C. J. & Seim, H. (1998) Annu. Rev. Nutr. 18, 39-61]. We show that LCAR prevents changes in hearing threshold and cochlear damage in newborn guinea pigs exposed to gentamicin in utero . Mechanistically, gentamicin-induced apoptosis of auditory cells is mediated by the extracellular signal-regulated kinase (ERK) 1/2 mitogen-activated protein kinase (MAPK) pathway through up-regulation of the proapoptotic factor Harakiri ( Hrk ). Most important, small interfering RNA (siRNA) experiments demonstrate that Hrk up-regulation is crucial for gentamicin-induced apoptosis. LCAR, in contrast, prevents both gentamicin-induced Hrk up-regulation and apoptosis acting by means of c-Jun N-terminal kinase (JNK). Together, these results outline pathways for gentamicin-induced hearing loss and its prevention and assign a key role to Hrk in these processes. Thus, our data offer a conceptual framework for designing clinical trials using a safe micronutrient, LCAR, as a simple preventive strategy for iatrogenically induced ototoxicity.

Frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) is caused by mutations in the gene encoding the microtubule-associated protein, tau. Some FTDP-17 mutations affect exon 10 splicing. To correct aberrant exon 10 splicing while retaining endogenous transcriptional control, we evaluated the feasibility of using spliceosome-mediated RNA trans-splicing (SMaRT) to reprogram tau mRNA. We designed a pre-trans-splicing molecule containing human tau exons 10 to 13 and a binding domain complementary to the 3′ end of tau intron 9. A minigene comprising tau exons 9, 10, and 11 and minimal flanking intronic sequences was used as a target. RT-PCR analysis of SH-SY5Y cells or COS cells cotransfected with a minigene and a pre-trans-splicing molecule using primers to opposite sides of the predicted splice junction generated products containing exons 9 to 13. Sequencing of the chimeric products showed that an exact exon 9–exon 10 junction had been created, thus demonstrating that tau RNA can be reprogrammed by trans-splicing. Furthermore, by using the same paradigm with a minigene containing full-length intronic sequences, we show that cis-splicing exclusion of exon 10 can be by-passed by trans-splicing and that conversion of exon 10 – tau RNA into exon 10 + tau RNA could be achieved with ≈34% efficiency. Our results demonstrate that an alternatively spliced exon can be replaced by trans-splicing and open the way to novel therapeutic applications of SMaRT for tauopathies and other disorders linked to aberrant alternative splicing.

A nonlinear model of the human aural system is proposed. Utilizing a homomorphic transformation, the model is implemented in a digital computer and accounts for the Fletcher critical bands in hearing, the nonlinear relationship between input sound intensity and perceived loudness known as recruitment, as well as the thresholds of audibility and the maximum tolerance threshold. The transformed or output signal domain is identified as a perceptual space. It is shown that the model can be used to reproduce the Fletcher Munson equal loudness contours for normal hearing populations. Modification of easily measured parameters results in the generation of equal loudness contours for hearing impaired individuals. Through a combination of the forward homomorphic transformation for normal hearing to the perceptual domain and the inverse mapping utilizing parameters of a hearing impaired individual, it is shown that hearing intelligibility is dramatically improved. It is postulated that signal processing performed in the perceptual domain will produce results more pleasing and intelligible to the listener. Results of auditory testing utilizing the proposed model for both normal and hearing impaired populations are presented. Speech intelligibility scores are shown to increase by more than 40% (i.e., from 40% to over 80%) over preprocessed scores under headphones for hearing impaired subjects used in these tests.

Purpose Most patients with colorectal liver metastases present to general surgeons and oncologists without a specialist interest in their management. Since treatment strategy is frequently dependent on the response to earlier treatments, our aim was to create a therapeutic decision model identifying appropriate procedure sequences. Methods We used the RAND Corporation/University of California, Los Angeles Appropriateness Method (RAM) assessing strategies of resection, local ablation and chemotherapy. After a comprehensive literature review, an expert panel rated appropriateness of each treatment option for a total of 1,872 ratings decisions in 252 cases. A decision model was constructed, consensus measured and results validated using 48 virtual cases, and 34 real cases with known outcomes. Results Consensus was achieved with overall agreement rates of 93.4 to 99.1%. Absolute resection contraindications included unresectable extrahepatic disease, more than 70% liver involvement, liver failure, and being surgically unfit. Factors not influencing treatment strategy were age, primary tumor stage, timing of metastases detection, past blood transfusion, liver resection type, pre-resection carcinoembryonic antigen (CEA), and previous hepatectomy. Immediate resection was appropriate with adequate radiologically-defined resection margins and no portal adenopathy; other factors included presence of ≤ 4 or > 4 metastases and unilobar or bilobar involvement. Resection was appropriate postchemotherapy, independent of tumor response in the case of ≤ 4 metastases and unilobar liver involvement. Resection was appropriate only for > 4 metastases or bilobar liver involvement, after tumor shrinkage with chemotherapy. When possible, resection was preferred to local ablation. Conclusion The results were incorporated into a decision matrix, creating a computer program (OncoSurge). This model identifies individual patient resectability, recommending optimal treatment strategies. It may also be used for medical education.

Purpose Bleomycin pulmonary toxicity (BPT) has been well described in Hodgkin's lymphoma (HL) patients treated with bleomycin-containing chemotherapy regimens. The influence of this pulmonary complication, along with the omission of bleomycin from further chemotherapy, on overall survival (OS) and progression-free survival (PFS) in HL remains unclear. We reviewed our experience with BPT in HL to better delineate outcome and appropriate treatment in these patients. Patients and Methods One hundred forty-one patients who were treated with bleomycin-containing chemotherapy for newly diagnosed HL between January 1986 and February 2003 were eligible for this retrospective review. BPT was defined by the presence of pulmonary symptoms, bilateral interstitial infiltrates, and no evidence of an infectious etiology. Results BPT was observed in 18% of patients. Increasing age, doxorubicin, bleomycin, vinblastine, and dacarbazine as initial therapy, and granulocyte colony-stimulating factor use were associated with the development of BPT. Patients with BPT had a median 5-year OS rate of 63% v 90% (P = .001) in unaffected patients. The mortality rate from BPT was 4.2% in all patients and 24% in patients who developed the pulmonary syndrome. BPT incidence and mortality were highest in patients older than 40 years. The omission of bleomycin had no impact on obtaining a complete remission, PFS, or OS. Conclusion BPT results in a significant decrease in 5-year OS in patients who are treated for HL. Age ≥ 40 years seems to add substantially to the risk. In patients who do not die from acute pulmonary toxicity, both OS and PFS seem equal, despite the omission of bleomycin.

Dyslipidemia often accompanies and accelerates renal disease, partly by promoting fibrosis. However, the mechanisms mediating this effect are unclear. We hypothesized that hypercholesterolemia modulates several interlinked pathways that promote deposition and blunt degradation of extracellular matrix, and that these could be manipulated by reversal of hypercholesterolemia. Fourteen pigs were fed a 16-week 2% high-cholesterol diet (HC-HC; n=7) or normal diet (n=7), whereas in 7 others, a 10-week HC was followed by a 6-week normal diet (HC-N). Renal endothelial function was assessed in vivo with electron-beam computed tomography, and renal tissue was then studied ex vivo using Western blot, real-time quantitative polymerase chain reaction, gelatin zymography, and immunostaining. HC-HC kidneys showed endothelial dysfunction, accompanied by increased intrarenal oxidative stress, inflammation, activation of the endothelin and transforming-growth factor-β systems, and decreased matrix metalloproteinase expression and activity. Accordingly, HC-HC kidneys showed increased collagen IV expression and fibrosis. A lipid-lowering dietary intervention reversed most of these changes. In conclusion, this study indicates that renal fibrosis in early atherosclerosis is a result of a simultaneous increase in extracellular matrix deposition and blunted matrix metalloproteinase–mediated degradation, overall promoting perivascular and tubulointerstitial fibrosis. Notably, many of these pathways may be reversible in hypercholesterolemia, and crucial targets could potentially be identified for early interventions to preserve the kidney.

Abstract Recent studies using glycogen synthase kinase-3β (GSK-3β)–deficient mouse embryonic fibroblasts suggest that GSK-3β positively regulates nuclear factor κB (NFκB)–mediated gene transcription. Because NFκB is suggested to participate in cell proliferation and survival pathways in pancreatic cancer, we investigated the role of GSK-3β in regulating these cellular processes. Herein, we show that pancreatic cancer cells contain a pool of active GSK-3β and that pharmacologic inhibition of GSK-3 kinase activity using small molecule inhibitors or genetic depletion of GSK-3β by RNA interference leads to decreased cancer cell proliferation and survival. Mechanistically, we show that GSK-3β influences NFκB-mediated gene transcription at a point distal to the Iκ kinase complex, as only ectopic expression of the NFκB subunits p65/p50, but not an Iκ kinase β constitutively active mutant, could rescue the decreased cellular proliferation and survival associated with GSK-3β inhibition. Taken together, our results simultaneously identify a previously unrecognized role for GSK-3β in cancer cell survival and proliferation and suggest GSK-3β as a potential therapeutic target in the treatment of pancreatic cancer.