Citations

OBJECTIVETo review the recent innovations in hearing aid technology.STUDY DESIGNReview of the literature.SETTINGPrivate tertiary referral otology/neurotology practice.RESULTSRecent innovations including digital signal processing (DSP), directional microphone technology, and open mold hearing aid fitting have resulted in improved satisfaction with current hearing aids.CONCLUSIONCurrent hearing aid technology with its innovations better meet needs of individuals who are hard of hearing.SIGNIFICANCEThe image commonly held of hearing aids by the general public is a negative one that can be improved with greater education.

ABSTRACTSeveral studies have demonstrated roles for eosinophils during innate and adaptive immune responses to helminth infections. However, evidence that eosinophils are capable of initiating an immune response to parasite antigens is lacking. The goal of the present in vitro study was to investigate the potential of eosinophils to serve as antigen-presenting cells (APC) and initiate an immune response to parasite antigens. Purified eosinophils were exposed to solubleStrongyloides stercoralisantigens, and the expression of various surface markers involved in cell activation was examined. Antigen-exposed eosinophils showed a sixfold increase in expression levels of CD69 and major histocompatibility complex (MHC) class II, a fourfold increase in levels of T-cell costimulatory molecule CD86, and a twofold decrease in levels of CD62L compared to eosinophils cultured in medium containing granulocyte-macrophage colony-stimulating factor. The ability of eosinophils to present antigen to T cells was determined by culturing them with T cells in vitro. Eosinophils pulsed with antigen stimulated antigen-specific primed T cells and CD4+T cells to increase interleukin-5 (IL-5) production. The blocking of MHC class II expression on eosinophils inhibited their ability to induce IL-5 production by CD4+T cells in culture. Antigen-pulsed eosinophils were able to prime naïve T cells and CD4+T cells in culture and polarized them into Th2 cells producing IL-5 similar to that induced by antigen-loaded dendritic cells. These results demonstrate that eosinophils are capable of activating antigen-specific Th2 cells inducing the release of cytokines and assist in the priming of naïve T cells to initiate Th2 responses against infection. This study highlights the potential of eosinophils to actively induce immune responses against infection by amplifying antigen-specific Th2-cell responses.

Background— The importance of completeness of revascularization by percutaneous coronary intervention in patients with multivessel disease is unclear in that there is little information on the impact of incomplete revascularization outside of randomized trials. The objective of this study is to compare long-term mortality and subsequent revascularization for percutaneous coronary intervention patients receiving stents who were completely revascularized (CR) with those who were incompletely revascularized (IR). Methods and Results— Patients from New York State’s Percutaneous Coronary Interventions Reporting System were subdivided into patients who were CR and IR. Then subsets of IR patients were contrasted with CR patients. Differences in long-term survival and subsequent revascularization for CR and IR patients were compared after adjustment for differences in preprocedural risk. A total of 68.9% of all stent patients with multivessel disease who were studied were IR, and 30.1% of all patients had total occlusions and/or ≥2 IR vessels. At baseline, the following patients were at higher risk: those who were older and those with more comorbid conditions, worse ejection fraction, and more renal disease and stroke. After adjustment for these baseline differences, IR patients were significantly more likely to die at any time (adjusted hazard ratio=1.15; 95% confidence interval, 1.01 to 1.30) than CR patients. IR patients with total occlusions and a total of ≥2 IR vessels were at the highest risk compared with CR patients (hazard ratio=1.36; 95% confidence interval, 1.12 to 1.66). Conclusions— IR with stenting is associated with an adverse impact on long-term mortality, and consideration should be given to either achieving CR, opting for surgery, or monitoring percutaneous coronary intervention patients with IR more closely after discharge.

Sphingolipids (SLs) play important roles in membrane structure and cell function. Here, we examine the SL requirements of various endocytic mechanisms using a mutant cell line and pharmacological inhibitors to disrupt SL biosynthesis. First, we demonstrated that in Chinese hamster ovary cells we could distinguish three distinct mechanisms of clathrin-independent endocytosis (caveolar, RhoA, and Cdc42 dependent) which differed in cargo, sensitivity to pharmacological agents, and dominant negative proteins. General depletion of SLs inhibited endocytosis by each clathrin-independent mechanism, whereas clathrin-dependent uptake was unaffected. Depletion of glycosphingolipids (GSLs; a subgroup of SLs) selectively blocked caveolar endocytosis and decreased caveolin-1 and caveolae at the plasma membrane. Caveolar endocytosis and PM caveolae could be restored in GSL-depleted cells by acute addition of exogenous GSLs. Disruption of RhoA- and Cdc42-regulated endocytosis by SL depletion was shown to be related to decreased targeting of these Rho proteins to the plasma membrane and could be partially restored by exogenous sphingomyelin but not GSLs. Both the in vivo membrane targeting and in vitro binding to artificial lipid vesicles of RhoA and Cdc42 were shown to be dependent upon sphingomyelin. These results provide the first evidence that SLs are differentially required for distinct mechanisms of clathrin-independent endocytosis.

Purpose To evaluate the efficacy and safety of arsenic trioxide monotherapy in patients with myelodysplastic syndromes (MDS). Patients and Methods Patients received arsenic trioxide (0.25 mg/kg/d) on 5 consecutive days per week for 2 weeks, followed by 2 weeks’ rest (one cycle). Two patient cohorts were established according to International Prognostic Scoring System risk category: lower-risk (low or intermediate-1) or higher-risk MDS (intermediate-2 or high). For lower-risk MDS, hematologic improvement (HI) was the primary response end point. For higher-risk MDS, additional end points included complete or partial remission. Based on the expected time to response, patients receiving two or more cycles were prospectively evaluated. Results Hematologic adverse events included neutropenia, thrombocytopenia, and febrile neutropenia. Two patients died during the study due to treatment-related toxicities. Most common grade 3/4 nonhematologic events were pneumonia, fatigue, hemorrhage, pain, and dyspnea. Among patients who received one or more doses (n = 70) or completed two or more cycles (n = 51), the HI rates were 34% and 39% in lower-risk patients, and 6% and 9% in higher-risk patients, respectively; the overall major HI rates were 20% and 22%. One higher-risk patient achieved a complete remission (3%). Major HIs were observed in all hematologic lineages; erythroid responses were the most common. Transfusion independence or reduction by ≥ 50% occurred in 33% of patients dependent on RBC transfusions. The overall median duration of HI was 6.8 months (range, 2 to 40 months). Conclusion Arsenic trioxide monotherapy has moderate activity against MDS, with a manageable adverse effect profile. The further study of arsenic trioxide in MDS, particularly in combination with other agents, is warranted.

Abstract Estrogen induction of progesterone receptor (PR) expression may be important to bone physiology because progesterone has been implicated in the control of bone formation and resorption. Although PR gene expression can be induced in osteoblasts by estrogen signaling through the estrogen receptor (ER) α isoform, it is unknown whether the ER-β isoform is involved in this regulation. The effect of estrogen on PR expression was examined in human fetal osteoblast (hFOB) cell lines stably transfected with either ER-α or ER-β. Estrogen treatment of hFOB/ER-α cells induced PR messenger RNA (mRNA) steady-state levels after 24 h and protein levels after 48 h, as established by competitive reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Interestingly, no induction of PR expression was observed in the hFOB/ER-β cells during this period. However, PR mRNA was induced progressively after 48 h of treatment with estrogen with maximum levels achieved at 12 days posttreatment. ER protein also was increased after 12 days of treatment. Both A and B isoforms of PR (PRA and PRB) were induced by estrogen in the hFOB/ER-α cells as well as much later in hFOB/ER-β cells. The pure antiestrogen ICI 182,780 prevented PR induction by estrogen in both cell lines. An ER-β-selective antagonist R, R-tetrahydrochrysene (THC) abolished the induction of PR mRNA in hFOB/ER-β but not in hFOB/ER-α cells, verifying that the response in the former cell line was ER-β-mediated. Transient cotransfection of hFOB cells with ER-α or ER-β together with either a human PRA or PRB promoter linked to a reporter plasmid revealed that although the PRB promoter was stimulated equally by estrogen activation of either ER isoform, PRA was activated preferentially by ER-α. Together, these results show that although estrogen can up-regulate endogenous PR gene expression in osteoblasts via both ER isoforms, ER-α is the predominant inducer.

Abstract Nutritional rickets is common in Nigeria where vitamin D deficiency is rare and dietary insufficiency of calcium is common. It occurs more commonly in siblings of affected children than of unaffected children. Postulating that vitamin D receptor (VDR) polymorphisms might relate to the susceptibility of some Nigerian children to develop rickets in the setting of low calcium intake, we compared the VDR genotypes, as determined by the presence or absence of Bsm I, Apa I, Taq I, and Fok I restriction enzyme cleavage sites, between 105 children with active nutritional rickets and 94 subjects representative of the community from which the rachitic children came. In the rickets group, the ff genotype was less common than in the community group, and the FF genotype was relatively increased (f allele frequency, 17% in rachitic children and 26% in the community group, p = 0.03). Neither individual allele frequencies for the other polymorphisms nor combinations of genotypes at different sites were different between the rachitic and community groups. Although it is not clear why a presumed better-functioning VDR variant (F allele) is associated with an increased risk of developing rickets, this study raises the possibility that VDR alleles might be important in determining an individual's susceptibility to developing rickets when faced with dietary calcium deficiency.

Abstract Although multiple hormones and cytokines regulate various aspects of osteoclast formation, the final two effectors are osteoprotegerin ligand (OPG-L)/osteoclast differentiation factor (ODF), a recently cloned member of the tumor necrosis factor superfamily, and macrophage colony–stimulating factor. OPG-L/ODF is produced by osteoblast lineage cells and exerts its biological effects through binding to its receptor, osteoclast differentiation and activation receptor (ODAR)/receptor activator of NF-κB (RANK), on osteoclast lineage cells, in either a soluble or a membrane-bound form, the latter of which requires cell-to-cell contact. Binding results in rapid differentiation of osteoclast precursors in bone marrow to mature osteoclasts and, at higher concentrations, in increased functional activity and reduced apoptosis of mature osteoclasts. The biological activity of OPG-L/ODF is neutralized by binding to osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF), a member of the TNF-receptor superfamily that also is secreted by osteoblast lineage cells. The biological importance of this system is underscored by the induction in mice of severe osteoporosis by targeted ablation of OPG/OCIF and by the induction of osteopetrosis by targeted ablation of OPG-L/ODF or overexpression of OPG/OCIF. Thus, osteoclast formation may be determined principally by the relative ratio of OPG-L/ODF to OPG/OCIF in the bone marrow microenvironment, and alterations in this ratio may be a major cause of bone loss in many metabolic disorders, including estrogen deficiency and glucocorticoid excess. That changes in but two downstream cytokines mediate the effects of large numbers of upstream hormones and cytokines suggests a regulatory mechanism for osteoclastogenesis of great efficiency and elegance.

Abstract Although the differentiation of mature osteoblasts has been well studied, there is still a need for a convenient way to study preosteoblast differentiation. Our laboratory has recently described a method for isolating small numbers of authentic osteoblast precursor cells from human bone marrow (Rickard et al., J Bone Miner Res 11:312–324, 1996). Here we describe the conditional immortalization of these cells by retroviral transfection with the amphotrophic vector, pZipSV40tsa58, which encodes for a temperature-sensitive mutant form of the simian virus large T-antigen. At the permissive temperature of 34°C, the cell lines proliferated, but differentiation was arrested, whereas at the restrictive temperature of 39.5°C, proliferation was decreased and differentiation was induced. As assessed by semiquantitative reverse transcriptase PCR after 4 days of culture at 39.5°C, the six cell lines expressed similar mRNA levels both constitutively and in response to dexamethasone (Dex) and 1α,25-dihydroxyvitamin D3 (1,25(OH2)D3) for osteoblast (alkaline phosphatase [ALP], type I collagen [Col I], osteocalcin [OC], and parathyroid hormone receptor [PTH-R] and adipocyte (lipoprotein lipase [LPL]) genes. In the presence of 10−8 M Dex, gene expression for ALP, PTH-R, and LPL increased, but that for OC decreased. Stimulation with 10−8 M 1,25(OH2)D3 increased gene expression for ALP, OC, and Col I. Changes in protein production for ALP, OC, and type I procollagen in response to Dex and 1,25(OH2)D3 were similar to changes in mRNA levels. When cultured at 39.5°C with ascorbate and β-glycerolphosphate for 21 days, mineralization of matrix occurred, whereas culture with Dex plus 1,25(OH2)D3, or rabbit serum led to enhanced formation of cytoplasmic lipid droplets within 6 days. Thus, these cell lines are capable of bipotential differentiation and should serve as an excellent tool to study the molecular mechanisms that regulate and select for osteoblast and adipocyte differentiation in humans.