Citations

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.

Background— Increases in vascular (Ea), ventricular systolic (Ees), and ventricular diastolic (Ed) elastance (stiffness) may contribute to the pathogenesis of heart failure (HF) with preserved ejection fraction (HFnlEF). The prevalence of HFnlEF increases strikingly with age, particularly in women. We hypothesized that ventricular-vascular stiffening may occur with age and be more pronounced in women in the general community. Methods and Results— In a cross-sectional sample of Olmsted County, Minn, residents ≥45 years old (n=2042), clinical data, Doppler echocardiography, and blood pressure (BP) measurements were obtained. Ea was calculated from stroke volume and systolic BP and indexed to body size (EaI). Ees was calculated by a modified single-beat method using systolic and diastolic BP, stroke volume, ejection fraction, timing intervals, and an estimated normalized ventricular elastance at arterial end diastole. Operant Ed was calculated from Doppler indices reflective of atrial pressures and the diastolic filling volume. EaI, Ees, and Ed all increased with age in men and in women ( P <0.0001 for all). Ees increased more steeply with age in women ( P =0.002). Adjusted for age, EaI, Ees, and Ed were higher in women than in men ( P <0.0001 for all). Findings were similar in those without known or suspected cardiovascular disease (n=623). Conclusions— In the community, advancing age and female gender are associated with increases in vascular and ventricular systolic and diastolic stiffness even in the absence of cardiovascular disease. We speculate that this combined ventricular-vascular stiffening may contribute to the increased prevalence of HFnlEF in elderly persons and particularly in elderly women.

Abstract We demonstrated that B-cell–dendritic cell (DC) interactions via transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI) and B-lymphocyte stimulator (BLyS) provide an early signal critical to generate adequate numbers of mature antigen presenting cells (APCs) to prime naive CD8+ T cells (CTLs) in vivo. Evidence that B cells are required for efficient CTL generation in mice and that reconstitution with wild-type but not TACI-knockout B cells restored normal CTL responses support our conclusion. Moreover, low doses of a TACI fusion protein (TACI-Fc) that express the extracellular domain of TACI (amino acid [aa] 1-126) restored CTL priming in B-cell–deficient mice in vivo and induced DC maturation in vitro. In fact, following interactions with B cells, splenic DCs rapidly express the CD86 costimulatory molecule, to an extent comparable to the exposure to antigenic stimuli. BLyShigh peptide-pulsed bone marrow–derived DCs, used as vaccines in vivo, cannot generate CTLs in B-cell–deficient and TACI-deficient mice, strongly supporting a need for B-cell–DC cooperation through TACI-BLyS during CTL first encounter with antigens in vivo.

Abstract Purpose: We sought to test the hypothesis that the presence of telomerase activity in peritoneal washings of patients treated for ovarian carcinoma is a sensitive and specific indicator of the presence of residual disease. We hypothesized that this test, if added to second-look procedure protocols, could help determine whether residual disease is present or not in patients who have completed their adjuvant chemotherapy for ovarian carcinoma. Experimental Design: Peritoneal washings were obtained from 100 consecutive patients undergoing a second-look procedure after treatment for ovarian carcinoma (cases) and from 100 patients undergoing surgery for benign gynecological conditions (controls). The washings were assayed for telomerase activity using the telomerase repeat amplification protocol. The results were compared to the histological and cytological findings. Results: Among our 100 cases, 82 (82%) had either positive second-look procedures or expressed telomerase in their peritoneal washings. Fifty-three (53%) had positive second-look procedures, whereas 66 (66%) tested positive for telomerase. Twenty-nine of the 47 patients (62%) with negative second-look procedures tested positive for telomerase. Of the 53 patients with positive second-look procedures, 37 (70%) tested positive for telomerase. None of the 100 controls (0%) expressed telomerase in their peritoneal washings. Conclusions: Telomerase activity in peritoneal washings of patients treated for ovarian carcinoma and undergoing a second-look procedure may provide a means of increasing the sensitivity of such procedures for the detection of residual disease while maintaining a high level of specificity.

Abstract Purpose: Most colorectal cancers that have high levels of microsatellite instability (MSI-H) show loss of immunohistochemical expression of proteins that participate in the DNA mismatch repair process, most often involving MLH1 and MSH2. Less commonly, a third DNA mismatch repair protein, MSH6, may also be lost as the primary event. Rarely, tumors with MSI-H show normal expression of these three proteins. The genetic deficiency leading to the MSI-H phenotype in such cases is unknown. PMS2 is another member of the DNA mismatch repair complex. Its expression is generally lost in tumors with MLH1 loss of expression. Rarely, there is selective loss of PMS2 expression. We sought to describe the frequency and clinical correlates of selective loss of expression of PMS2 with the MSI-H tumor phenotype. Experimental Design: Two thousand seven hundred nineteen colorectal cancers from both clinic- and research-based ascertainment were studied. Tumor MSI testing and immunohistochemistry for MLH1, MSH2, MSH6, and PMS2 were conducted. Medical records were abstracted for age at diagnosis, gender, colorectal cancer site, and family history. Results: Five hundred thirty-five of the 2,719 tumors were MSI-H. Of these, 93% showed loss of expression of MLH1, MSH2, and/or MSH6. Thirty-eight showed normal expression for these proteins. PMS2 immunohistochemical staining was successful in 32 of 38 of these tumors. Of the 32, 23 showed selective loss of expression of PMS2. This was associated with young age of diagnosis and right-sided location but not with a striking family history of cancer. Conclusions: Overall, 97% of the MSI-H tumors showed loss of expression for one or more of these four mismatch repair proteins. Selective loss of expression of PMS2 was present in 72% of cases in which colorectal cancers had an MSI-H phenotype but no alteration of expression of MLH1, MSH2, and MSH6. The underlying mechanism involved cannot be determined from this study but could involve point mutations in other DNA mismatch repair genes with retention of immunohistochemical expression, somatic inactivation of PMS2, or germ line mutation of PMS2.

ABSTRACT Cell wall β-glucans are highly conserved structural components of fungi that potently trigger inflammatory responses in an infected host. Identification of molecular mechanisms responsible for internalization and signaling of fungal β-glucans should enhance our understanding of innate immune responses to fungi. In this study, we demonstrated that internalization of fungal β-glucan particles requires actin polymerization but not participation of components of caveolar uptake mechanisms. Using fluorescence microscopy, we observed that uptake of 5-([4,6-dichlorotriazin-2-yl] amino)-fluorescein hydrochloride-Celite complex-labeled Saccharomyces cerevisiae β-glucan by RAW macrophages was substantially reduced in the presence of cytochalasin D, which antagonizes actin-mediated internalization pathways, but not by treatment with nystatin, which blocks caveolar uptake. Interestingly, β-glucan-induced NF-κB translocation, which is necessary for inflammatory activation, and tumor necrosis factor alpha production were both normal in the presence of cytochalasin D, despite defective internalization of β-glucan particles following actin disruption. Dectin-1, a major β-glucan receptor on macrophages, colocalized to phagocytic cups on macrophages and exhibited tyrosine phosphorylation after challenge with β-glucan particles. Dectin-1 localization and other membrane markers were not affected by treatment with cytochalasin D. Furthermore, dectin-1 receptors rather than Toll-like receptor 2 receptors were shown to be necessary for both efficient internalization of β-glucan particles and cytokine release in response to the fungal cell wall component.

The physical attributes of the three capitohamate interosseous ligaments were tested in a computer-controlled multi-axis testing machine using 12 human cadaver specimens. After an intact test run, selected ligaments were cut in random sequence and the test repeated. The remaining ligaments were tested to failure with servohydrolic stress at 5 mm/second. In the intact joint complex, the average dorsopalmar rotational displacement was approximately 9° in each direction. Under the load limit, the dorsopalmar translational displacement averaged 0.9 mm and 0.5 mm respectively, proximal–distal translational displacement averaged 0.8 mm and 0.4 mm respectively, and distractional displacement averaged 0.3 mm. Based on the sequential sectioning it was found that the dorsal ligament provided 76% (SD 14) of the rotational resistance with palmar rotation of the capitate and 44% (SD 19) of translational constraint with palmar translation of the capitate. The deep ligament provided 51% (SD 15) of the rotational resistance with dorsal rotation of the capitate and 63% (SD 24) of translational resistance with dorsal translation of the capitate. With proximal—distal translation, the dorsal ligament was the most important constraint in each direction. In resisting distraction, each of the three ligaments was equally effective. Failure testing showed the deep ligament was strongest at 289 N, followed by the palmar at 171 N and the dorsal at 133 N.

Abstract The MutLα heterodimer formed by mismatch repair (MMR) proteins MLH1 and PMS2 is a major component of the MMR complex, yet mutations in the PMS2 gene are rare in the etiology of hereditary nonpolyposis colorectal cancer. Evidence from five published cases suggested that contrary to the Knudson principle, PMS2 mutations cause hereditary nonpolyposis colorectal cancer or Turcot syndrome only when they are biallelic in the germline or abnormally expressed. As candidates for PMS2 mutations, we selected seven patients whose colon tumors stained negative for PMS2 and positive for MLH1 by immunohistochemistry. After conversion to haploidy, truncating germline mutations of PMS2 were found in two patients (2192delTAACT and deletion of exon 8). These mutations abrogated PMS2 protein in germline cells by Western analysis. In two additional patients, PMS2 protein from one allele also was abrogated. Novel or previously described missense variants of PMS2 were detected, but their pathogenicity is undetermined. We detected and characterized a new transcript, PMS2CL, showing 98% sequence identity with exons 9 and 11–15 of PMS2 and emanating from a locus close to PMS2 in chromosome 7p. Its predicted protein product was not detected. Thus, in addition to several previously described PMS2-related genes resembling the 5′ end of PMS2, at least one related gene resembles the 3′ end of PMS2. In conclusion, both detectable and presently undefined germline mutations are deleterious and produce susceptibility to cancer by the two-hit mechanism. Paralogous genes interfere with mutation detection, resulting in underdiagnosis of PMS2 mutations. Mutation detection in PMS2 requires haploid DNA.

Abstract Objective: Predictors of quality of life (QOL) in patients with metastatic colorectal cancer are lacking. The insulin-like growth factor (IGF) family of proteins is associated with QOL in noncancer populations. We sought to study whether these proteins are associated with QOL in patients with colorectal cancer. Method: We used a cohort of 526 patients with metastatic colorectal cancer treated with combination chemotherapy. Plasma samples of IGF-I, IGF-II, IGF binding protein-3, and C-peptide were collected before initiation of chemotherapy. QOL was measured by the uniscale instrument and the Symptom Distress Scale at baseline and throughout treatment. Results: Baseline plasma levels of IGF-I and IGF-II before initiation of chemotherapy were significantly associated with several important baseline QOL measures in patients with metastatic colorectal cancer. Patients with lower levels of IGF-I reported increased distress with regard to appearance, appetite, cough, and nausea intensity after adjustment for potential confounders. Similarly, decreased levels of IGF-II were predictive of worse quality related to appearance, appetite, fatigue, nausea frequency and intensity, pain frequency, and composite Symptom Distress Scale score. IGF binding protein-3 and C-peptide were not predictive of baseline QOL. Baseline biomarkers were not associated with subsequent changes in QOL during treatment. Higher body mass index was significantly associated with superior baseline QOL in several areas; nonetheless, the association of IGF-I and IGF-II with baseline QOL measures remained significant even after controlling for baseline body mass index. Conclusion: Baseline plasma IGF-I and IGF-II are significantly associated with symptom distress. Whether this association is simply reflective of patient nutritional status and/or disease burden or represents an independent biological effect of IGFs on QOL remains uncertain. Nonetheless, these data suggest that molecular biomarkers may be useful predictors of QOL in cancer patients.