Incidence of melanoma and non-melanoma skin cancer in patients with celiac disease: a systematic review and meta-analysis

There is conflicting observational evidence regarding the association between skin cancer and celiac disease (CD). The purpose of this review was to investigate the incidence rate ratio (IRR) of skin cancer incidence between patients with and without CD. MEDLINE and EMBASE databases were searched on October 27th, 2021 and eight articles were identified for review. Quality assessment was conducted using the Newcastle Ottawa Scale. Seven articles were included in meta-analysis for a pooled estimate of IRR across all skin cancers, malignant melanoma (MM), and non-melanoma skin cancers (NMSC). In total, 74,860 CD patients were followed for 710,214 person-years in the meta-analysis. Overall combined incidence was 99.8 cases per 100,000 person-years. Meta-analysis of all skin cancer incidence showed no significant difference in CD patients compared to controls (IRR: 1.06; 95% CI: 0.95, 1.17; p=0.29; I2: 0%). Five studies reported on MM incidence; there was no significant difference in incidence compared to controls (IRR: 0.87, 95% CI: 0.72, 1.06; p=0.22; I2: 9%). Five studies reported on NMSC incidence, revealing a significantly increased risk of NMSC in CD patients (IRR: 1.14; 95% CI: 1.01, 1.28; p=0.04; I2: 0%). Our findings suggest a significantly increased incidence of NMSC in CD patients compared to control data and no significant association between CD and MM incidence. The findings are limited by the quantity and quality of the evidence. Nonetheless, clinicians should emphasize the importance of sun protection, such as sunscreen usage and self-examination for patients with CD.

The appropriateness and quality of patient-reported outcome measures (PROMs) in plastic surgery randomized controlled trials: A systematic review

BACKGROUND

Patient-reported outcome measures (PROMs) quantify patient perspectives to measure outcomes that matter to patients. The aim of this study was to assess the reporting of appropriateness and quality of PROM selection in plastic surgery randomized controlled trials (RCTs).

METHODS

MEDLINE, Embase, and CENTRAL were searched from January 1, 2000, to June 5, 2022, to identify published RCTs within the plastic surgery literature. Included studies were categorized as follows: 1) a clearly defined patient-reported primary outcome; 2) a primary outcome could be inferred; or 3) no clear or implied primary outcome. The Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) database was consulted to assess the available literature on the PROMs.

RESULTS

There were 130 plastic surgery RCTs identified. Of the 43 studies with a clear or inferred primary outcome, the percentage of studies that commented with supporting references on the PROM's appropriateness for the population, disease/condition, and outcome were 20.9% (n = 9/43), 18.6% (n = 8/43), and 27.9% (n = 12/43), respectively. The percentage of studies that commented on the PROM's validity, reliability, and responsiveness with supporting references were 34.9% (n = 15/43), 14.0% (n = 6/43), and 11.7% (n = 5/43), respectively. There were 21 unique PROMs identified; 28.6% (n = 6/21) were available in the COSMIN database.

CONCLUSION

The majority of plastic surgery RCTs assessing patient-reported primary outcomes lack transparency surrounding PROM selection and quality. We recommend investigators conducting plastic surgery clinical research report explicitly why they used a particular PROM and support its appropriateness and psychometric properties with supporting references. Finally, they should familiarize themselves with the COSMIN initiative.

A Systematic Review and Meta-Analysis of Injection Site Reactions in Randomized-Controlled Trials of Biologic Injections

BACKGROUND

Biologic agents are emerging as an important treatment option for immune-mediated diseases. Injection site reactions following subcutaneous injection of biologic agents is not well described in the literature.

OBJECTIVE

To summarize injection site reaction data in phase 3 trials of all biologic agents.

METHODS

MEDLINE, Embase, and CENTRAL databases were systematically searched on February 8, 2022. Proportional meta-analysis was conducted to summarize injection site reaction prevalence for each biologic.

RESULTS

There were 158 articles included in the review. The most common types of injection site reactions were erythema (42.8%), unspecified reaction (23.3%), pain (12.4%), and pruritus (5.7%). No patients discontinued their treatment due to injection site reactions in 39 of the 48 studies that reported on discontinuation data. There were 16 biologics included in meta-analysis across 80 eligible studies. The biologics with the highest point prevalence of patients reporting injection site reactions were Canakinumab (15.5%; 294 patients), Dupilumab (11.4%; 1888 patients), Etanercept (11.4%; 4363 patients), and Ixekizumab (11.2%; 2205 patients). The biologics with the lowest point prevalence of injection site reactions were Risankizumab (0.8%; 707 patients), Brodalumab (1.3%; 1365 patients), Guselkumab (1.3%; 1852 patients), Secukinumab (1.9%; 1277 patients).

CONCLUSIONS

The prevalence of injection site reaction in response to biologics ranges from 0.08 to 15.5%. Canakinumab, Dupilumab, Etanercept, and Ixekizumab had the highest prevalence of injection site reactions. Risankizumab, Brodalumab, Guselkumab, and Secukinumab had the lowest prevalence of injection site reactions. Recommendations are made regarding the improvement of adverse event reporting to better understand the epidemiology of injection site reactions.

"Spin" in Observational Studies in Deep Inferior Epigastric Perforator Flap Breast Reconstruction: A Systematic Review

The deep inferior epigastric artery perforator (DIEP) flap is widely used in autologous breast reconstruction. However, the technique relies heavily on nonrandomized observational research, which has been found to have high risk of bias. "Spin" can be used to inappropriately present study findings to exaggerate benefits or minimize harms. The primary objective was to assess the prevalence of spin in nonrandomized observational studies on DIEP reconstruction. The secondary objectives were to determine the prevalence of each spin category and strategy.

Methods

MEDLINE and Embase databases were searched from January 1, 2015, to November 15, 2022. Spin was assessed in abstracts and full-texts of included studies according to criteria proposed by Lazarus et al.

Results

There were 77 studies included for review. The overall prevalence of spin was 87.0%. Studies used a median of two spin strategies (interquartile range: 1-3). The most common strategies identified were causal language or claims (n = 41/77, 53.2%), inadequate extrapolation to larger population, intervention, or outcome (n = 27/77, 35.1%), inadequate implication for clinical practice (n = 25/77, 32.5%), use of linguistic spin (n = 22/77, 28.6%), and no consideration of the limitations (n = 21/77, 27.3%). There were no significant associations between selected study characteristics and the presence of spin.

Conclusions

The prevalence of spin is high in nonrandomized observational studies on DIEP reconstruction. Causal language or claims are the most common strategy. Investigators, reviewers, and readers should familiarize themselves with spin strategies to avoid misinterpretation of research in DIEP reconstruction.

A comparison of skin grafts versus local flaps for facial skin cancer from the patient perspective: protocol for a feasibility study

BRIEF ABSTRACT

This is a protocol to assess feasibility of conducting a prospective cohort study comparing local flaps versus skin grafts for surgical excision of skin cancer from the face.

INTRODUCTION

Skin cancer is the most common malignancy worldwide and the face is one of the most common locations of occurrence. Surgical excision is the most popular treatment for small lesions of the face. Defects can be reconstructed using local flaps or skin grafts. There is a paucity of literature evaluating outcomes after skin cancer surgery from the patient's perspective using valid measurement tools. The purpose of this study is to assess the feasibility of conducting a prospective observational cohort study. The primary outcomes include recruitment rates, eligibility rate, compliance of intervention and rate of completion of the primary outcome (FACE-Q scales) at 3 months. Secondary outcomes include examining patient characteristic and FACE-Q score differences between local flaps to skin grafts and adverse events.

METHODS AND ANALYSIS

This study is a prospective cohort study consisting of an anticipated 30 patients aged ≥18 years. The study population will consist of a consecutive sample of non-melanoma facial skin cancer patients undergoing a skin graft or local flap. Patients will be followed and evaluated with the FACE-Q questionnaire at 2 weeks, 3 months, 6 months and 1 year post-operation. The following criteria will determine success: patients who meet eligibility criteria >70%; recruitment rate >70%; compliance with intervention >90%; rate of completion of full-scale prospective study primary outcome (FACE-Q at 3 months) >80%; retention rate at 6-month follow-up visit >70%.

DISCUSSION

The findings of this study will be used to guide the sample size calculation for a future, large-scale prospective study.Trial registration: ClinicalTrials.gov (NCT04842279).

Sodium-glucose co-transporter-2 inhibitors after acute myocardial infarction in type 2 diabetes patients: a population-based investigation from South Korea

Background

Whether the early use of sodium-glucose co-transporter-2 (SGLT2) inhibitors has cardioprotective effects following acute myocardial infarction (AMI) is unknown.

Purpose

We aimed to evaluate the association between the early initiation of SGLT2 inhibitors and cardiac event rates in diabetes patients with AMI undergoing percutaneous coronary intervention (PCI).

Methods

Based on the National Health Insurance claims data in South Korea, patients aged 18 years or older who had undergone PCI for the diagnosis of AMI between 2014 and 2018 were analyzed. Patients treated with SGLT2 inhibitors or other glucose-lowering drugs were matched based on a propensity score. The primary endpoint was a composite of all-cause mortality and hospitalizations for heart failure (HF). Major adverse cardiac events (MACE; a composite of all-cause death, non-fatal MI, and ischemic stroke) were compared as the secondary endpoint.

Results

After 1:2 propensity score matching, a total of 26,814 patients were assigned to the SGLT2 inhibitors group (938 patients) and the no use of SGLT2 inhibitors group (1,876 patients), respectively. During a median follow-up of 2.1 years, compared to no use of SGLT2 inhibitors, the early use of SGLT2 inhibitors was associated with lower risks of both the primary endpoint (9.8% vs. 13.9%, adjusted hazard ratio [HR] = 0.68, 95% confidence interval [CI]: 0.54 to 0.87, p=0.002) and secondary endpoint (9.1% vs. 11.6%, adjusted HR = 0.77, 95% CI: 0.60 to 0.99, p=0.04) (Figure 1). All-cause mortality and hospitalizations for HF were significantly lower in the early use of SLGT2 inhibitors group (adjusted HR = 0.55; 95% CI: 0.37 to 0.80; p=0.002; and HR = 0.74; 95% CI: 0.56 to 0.98; p=0.03, respectively). The incidence of non-fatal MI and ischemic stroke were not statistically different (Figure 2).

Conclusions

The early use of SGLT2 inhibitors in diabetes patients treated with PCI for AMI was associated with a significantly lower risk of cardiovascular events including all-cause mortality, hospitalizations for HF, and MACE. Our results suggest that the use of SGLT2 inhibitors could expand to the acute phase of AMI survivors with diabetes to reduce mortality and the subsequent development of congestive HF and ischemic events.

Funding Acknowledgement

Type of funding sources: Private hospital(s). Main funding source(s): This work was partly supported by the Research Institute of Medical Science, The Catholic University of Korea, Eunpyeong St. Mary's Hospital, Seoul, Republic of Korea.

Stewart-Treves syndrome and other cutaneous malignancies in the context of chronic lymphedema: a systematic review

INTRODUCTION

Angiosarcoma developing in chronically lymphedematous tissue, or Stewart-Treves syndrome (STS), is a rare and lethal complication of lymphedema. This systematic review summarizes characteristics and outcomes of STS and other cutaneous malignancies arising in chronic lymphedema.

METHODS

MEDLINE and EMBASE databases were searched on February 19th, 2021, to identify 200 articles included in the analysis.

RESULTS

Of 369 included patients, 89.7% (n = 331/369) had STS and 10.3% (n = 38/369) had other associated malignancies. Mean age of onset was 61.2 years, and 85.9% (n = 317/369) of cases were female. Common risk factors were previous cancer history (69.8%, n = 258/369) and radiation history (53.7%, n = 198/369). Lymphedema was most commonly attributed to surgical causes (68.3%, n = 252/369). STS begins on average 14.9 years after lymphedema with mortality of 53.9% (n = 178/331) and remission rate of 16.1% (n = 53/331). Other malignancies begin on average 23.7 years after lymphedema, with mortality of 10.5% (n = 4/38) and remission rate of 31.6% (n = 12/38). STS and other malignancies had 5-year survivals of 22.4% and 65.2%, respectively (P = 0.00145). For all patients, patients initially treated with excision had the best survival (median: 48 months, 5-year survival: 43.3%) and radiotherapy had the worst survival (median: 10 months, 5-year survival: 6.5%) (P = 0.0141).

CONCLUSION

Malignancy can appear in lymphedematous tissue many years after lymphedema onset. STS has poorer prognosis compared to other malignancies. Further research should be conducted to better understand the causes, risk factors, and management of this phenomenon.

Clinical manifestations and treatment outcomes in degos disease: a systematic review

Degos disease (atrophic papulosis) is a rare vasculopathy with cutaneous and systemic manifestations. Although potentially fatal, the characteristics of and treatments for Degos disease variants are not adequately described. We conducted a systematic review to summarize cutaneous and systemic presentations, treatments and outcomes of malignant (MAP) and benign (BAP) variants of Degos disease. A comprehensive search was conducted on Embase, MEDLINE, CINAHL and CENTRAL on 27 October 2020, which yielded 254 original studies reporting cases of Degos disease. A total of 357 patients were included in the analysis. Mean age of onset was 33.9 years. MAP was most commonly reported (63.8%, n = 228/357), with 56.6% (n = 129/228) mortality. Cutaneous lesions were usually asymptomatic (26.3%, n = 81/308) and localized to the trunk (57.7%, n = 206/357) and extremities (56.8%, n = 203/357). Systemic involvement developed within 2 years on average, ranging from 0 to 28 years. Anti-platelet monotherapy had a complete resolution rate of 42.3% (n = 11/26) in BAP and 20.0% (n = 7/35) in MAP. Based on the findings of the study, most cases of Degos disease are malignant with high mortality, and even benign cutaneous cases may develop systemic disease in as late as 28 years. Anti-platelet monotherapies may prove effective against both variants. Further studies are needed to confirm these findings.

Rapid disappearance of influenza following the implementation of COVID-19 mitigation measures in Hamilton, Ontario

Background

Public health measures, such as social distancing and closure of schools and non-essential services, were rapidly implemented in Canada to interrupt the spread of the novel coronavirus disease 2019 (COVID-19).

Objective

We sought to investigate the impact of mitigation measures during the spring wave of COVID-19 on the incidence of other laboratory-confirmed respiratory viruses in Hamilton, Ontario.

Methods

All nasopharyngeal swab specimens (n = 57,503) submitted for routine respiratory virus testing at a regional laboratory serving all acute-care hospitals in Hamilton, Ontario between January 2010 and June 2020 were reviewed. Testing for influenza A/B, respiratory syncytial virus, human metapneumovirus, parainfluenza Iâ€"III, adenovirus and rhinovirus/enterovirus was done routinely using a laboratory-developed polymerase chain reaction multiplex respiratory viral panel. A Bayesian linear regression model was used to determine the trend of positivity rates of all influenza samples for the first 26 weeks of each year from 2010 to 2019. The mean positivity rate of Bayesian inference was compared with the weekly reported positivity rate of influenza samples in 2020.

Results

The positivity rate of influenza in 2020 diminished sharply following the population-wide implementation of COVID-19 interventions. Weeks 12-26 reported 0% positivity for influenza, with the exception of 0.1% reported in week 13.

Conclusions

Public health measures implemented during the COVID-19 pandemic were associated with a reduced incidence of other respiratory viruses and should be considered to mitigate severe seasonal influenza and other respiratory virus pandemics.

Surface Functionalization of Carbon Architecture with Nano-MnO2 for Effective Polysulfide Confinement in Lithium-Sulfur Batteries

Li-S batteries have received tremendous attention owing to their high theoretical capacity (1672 mA h g^-1 ), sulfur abundance, and low cost. However, main systemic issues, associated with polysulfide shuttling and low Coulombic efficiency, hinder the practical use of the sulfur electrode in commercial batteries. Herein, we demonstrate an effective strategy of decorating nano-MnO₂ (less than 10 wt %) onto the sulfur reservoir to capture the out-diffused polysulfides through chemical interaction and thereby improve the electrochemical performance of the sulfur electrode without increasing the mass burden of total battery configuration. Pistachio shell-derived sustainable carbon (PC) was employed as effective sulfur containers owing to its structural characteristics (interconnected macro channels and micropores). With the aids of the structural benefits of the PC scaffold and the uniform decoration of nano-MnO₂ , polysulfide shuttling was significantly suppressed and the cycling performance of the sulfur cathode was dramatically improved over 250 cycles.

Toward High-Performance Lithium-Sulfur Batteries: Upcycling of LDPE Plastic into Sulfonated Carbon Scaffold via Microwave-Promoted Sulfonation

Lithium-sulfur batteries were intensively explored during the last few decades as next-generation batteries owing to their high energy density (2600 Wh kg^-1) and effective cost benefit. However, systemic challenges, mainly associated with polysulfide shuttling effect and low Coulombic efficiency, plague the practical utilization of sulfur cathode electrodes in the battery market. To address the aforementioned issues, many approaches have been investigated by tailoring the surface characteristics and porosities of carbon scaffold. In this study, we first present an effective strategy of preparing porous sulfonated carbon (PSC) from low-density polyethylene (LDPE) plastic via microwave-promoted sulfonation. Microwave process not only boosts the sulfonation reaction of LDPE but also induces huge amounts of pores within the sulfonated LDPE plastic. When a PSC layer was utilized as an interlayer in lithium-sulfur batteries, the sulfur cathode delivered an improved capacity of 776 mAh g^-1 at 0.5C and an excellent cycle retention of 79% over 200 cycles. These are mainly attributed to two materialistic benefits of PSC: (a) porous structure with high surface area and (b) negatively charged conductive scaffold. These two characteristics not only facilitate the improved electrochemical kinetics but also effectively block the diffusion of polysulfides via Coulomb interaction.

Expanding the Klebsiella pneumoniae volatile metabolome using advanced analytical instrumentation for the detection of novel metabolites

AIMS

The purpose of this study was to identify the volatile molecules produced by the pathogenic Gram-negative bacterium Klebsiella pneumoniae (ATCC 13883) during in vitro growth using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOFMS).

METHODS AND RESULTS

Klebsiella pneumoniae ATCC 13883 was incubated in lysogeny broth to mid-exponential and stationary growth phases. Headspace volatile molecules from culture supernatants were concentrated using solid-phase microextraction (SPME) and analysed via GC×GC-TOFMS. Ninety-two K. pneumoniae-associated volatile molecules were detected, of which 78 (85%) were detected at both phases of growth and 14 (15%) were detected at either mid-exponential or stationary growth phases.

CONCLUSIONS

This study has increased the total number of reported K. pneumoniae-associated volatile molecules from 77 to 150, demonstrating the sensitivity and resolution achieved by employing GC×GC-TOFMS for the analysis of bacterial headspace volatiles.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study represents an early-stage comprehensive volatile metabolomic analysis of an opportunistic bacterial pathogen. Characterizing the volatile molecules produced by K. pneumoniae during in vitro growth could provide us with a better understanding of this organisms' metabolism, an area that has not been extensively studied to date.

Mitigating yield-scaled greenhouse gas emissions through combined application of soil amendments: A comparative study between temperate and subtropical rice paddy soils

Effects of different soil amendments were investigated on methane (CH4) and nitrous oxide (N2O) emissions, global warming potential (GWP) and yield scaled GWPs in paddy soils of Republic of Korea, Japan and Bangladesh. The experimental treatments were NPK only, NPK+fly ash, NPK+silicate slag, NPK+phosphogypsum(PG), NPK+blast furnace slag (BFS), NPK+revolving furnace slag (RFS), NPK+silicate slag (50%)+RFS (50%), NPK+biochar, NPK+biochar+Azolla-cyanobacteria, NPK+silicate slag+Azolla-cyanobacteria, NPK+phosphogypsum (PG)+Azolla-cyanobacteria. The maximum decrease in cumulative seasonal CH4 emissions was recorded 29.7% and 32.6% with Azolla-cyanobacteria plus phospho-gypsum amendments in paddy soils of Japan and Bangladesh respectively, followed by 22.4% and 26.8% reduction with silicate slag plus Azolla-cyanobacteria application. Biochar amendments in paddy soils of Japan and Bangladesh decreased seasonal cumulative N2O emissions by 31.8% and 20.0% respectively, followed by 26.3% and 25.0% reduction with biochar plus Azolla-cyanobacteria amendments. Although seasonal cumulative CH4 emissions were significantly increased by 9.5-14.0% with biochar amendments, however, global warming potentials were decreased by 8.0-12.0% with cyanobacterial inoculation plus biochar amendments. The maximum decrease in GWP was calculated 22.0-30.0% with Azolla-cyanobacteria plus silicate slag amendments. The evolution of greenhouse gases per unit grain yield (yield scaled GWP) was highest in the NPK treatment, which was decreased by 43-50% from the silicate slag and phosphogypsum amendments along with Azolla-cyanobacteria inoculated rice planted soils. Conclusively, it is recommended to incorporate Azolla-cyanobacteria with inorganic and organic amendments for reducing GWP and yield scaled GWP from the rice planted paddy soils of temperate and subtropical countries.

Intrinsic hyporesponsiveness of invariant natural killer T cells precedes the onset of lupus

Patients with systemic lupus erythematosus (SLE) display reduced numbers and functions of invariant natural killer T (iNK T) cells, which are restored upon treatment with corticosteroids and rituximab. It is unclear whether the iNK T cell insufficiency is a consequence of disease or is a primary abnormality that precedes the onset of disease. To address this, we analysed iNK T cell function at different stages of disease development using the genetically lupus-susceptible NZB × NZW F1 (BWF(1)) model. We found that iNK T cell in-vivo cytokine responses to an iNK T cell ligand α-galactosylceramide (α-GalCer) were lower in BWF(1) mice than in non-autoimmune BALB/c and major histocompatibility complex (MHC)-matched NZB × N/B10.PL F1 mice, although iNK T cell numbers in the periphery were unchanged in BWF(1) mice compared to control mice. Such iNK T cell hyporesponsiveness in BWF(1) mice was detected at a young age long before the animals exhibited any sign of autoimmunity. In-vivo activation of iNK T cells is known to transactivate other immune cells. Such transactivated T and B cell activation markers and/or cytokine responses were also lower in BWF(1) mice than in BALB/c controls. Finally, we show that iNK T cell responses were markedly deficient in the NZB parent but not in NZW parent of BWF(1) mice, suggesting that BWF(1) might inherit the iNK T cell defect from NZB mice. Thus, iNK T cells are functionally insufficient in lupus-prone BWF(1) mice. Such iNK T cell insufficiency precedes the onset of disease and may play a pathogenic role during early stages of disease development in SLE.

Effect of limited nickel availability on methane emission from EDTA treated soils: coenzyme M an alternative biomarker for methanogens

Methanogens utilize simple carbon compounds to produce methane (CH(4)) under strictly anaerobic condition. During methanogenesis, methyl coenzyme M (MeCoM) is reduced by MeCoM reductase enzyme to CH(4) involving a nickel-containing cofactor F(430). In this experiment, strong chelating agent like ethylenediaminetetraacetic acid (EDTA) was applied in soil to study its feasibility for suppressing methanogen activity and CH(4) production in soil. Application of EDTA significantly (P≤0.05) reduced CH(4) production in soil. Application of 60 ppm EDTA (soil weight basis) was the most effective among all treatments. Applied EDTA forms complex compounds with heavy metals like nickel (Ni) and increases Ni concentration in soil solution. Since methanogenesis is intracellular process, it is necessary for methanogens to assimilate those Ni-EDTA complexes inside cell to utilize Ni in EDTA treated soils. Results indicated that methanogens cannot utilize Ni in the presence of EDTA and that significantly (P≤0.05) reduced mcrA gene (coding MeCoM reductase enzyme) copy number and Co-M concentration in soil. Due to high correlation (r=0.901(*)) between Co-M concentration and mcrA gene copy numbers, Co-M concentration could be used as an alternative biomarker for methanogens. Therefore, it could be propose that 60 ppm EDTA could be an optimum dose to suppress CH(4) emission from soil by restricting Ni availability to methanogens.

Disparate effects of depletion of CD1d-reactive T cells during early versus late stages of disease in a genetically susceptible model of lupus

Some T cells react with lipid antigens bound to antigen-presenting molecule CD1d. Numbers and functions of a subset of such lipid-reactive T cells are reduced in patients with systemic lupus erythematosus (SLE) and their relatives, as well as in genetically susceptible and chemically induced animal models of lupus-like disease. We have reported that the germline deletion of CD1d exacerbates lupus, suggesting a protective role of these cells in the development of lupus. The use of a knockout mouse model in this study, however, did not allow examination of the role of these cells at different stages of disease. Here, we describe an approach to deplete CD1d-dependent T cells, which allowed us to investigate the role of these cells at different stages of disease in genetically lupus-prone NZB/NZW F1 (BWF1) mice. Repeated intravenous injections of large numbers of CD1d-transfected cells resulted in ∼50-75% reduction in these cells, as defined by the expression of CD4, NK1.1 and CD122, and lack of expression of CD62 ligand. TCR γδ (+)NK1.1(+) cells were also reduced in the recipients of CD1d-transfected cells as compared with control recipients. Such depletion of CD1d-reactive T cells in preclinical BWF1 mice resulted in disease acceleration with a significant increase in proteinuria and mortality. In older BWF1 mice having advanced nephritis, however, such depletion of CD1d-reactive T cells resulted in some disease improvement. Taken together, these data as well as our published studies suggest that CD1d-reactive T cells protect against the development of lupus in animal models. However, these cells appear to be unable to suppress established lupus nephritis in these animals, and might even play a disease aggravating role in late stages of disease.

Contrast echocardiography: finding its place in stem cell therapy

To date, the underlying mechanism responsible for the restoration of the injured myocardium following transplantation of stem cells has not been clearly identified. Molecular imaging is essential to the continued progress of stem cell therapy by elucidating the biology of transplanted stem cells in vivo. Currently, several imaging modalities are in development in the rapidly evolving field of molecular imaging. Contrast echocardiography has the potential to define its role in shaping the future development of stem cell therapy. We describe the current state of contrast echocardiography and its future direction herein.

Transgenic expression of survivin in keratinocytes counteracts UVB-induced apoptosis and cooperates with loss of p53

The inhibitor of apoptosis protein survivin has been implicated in both cell cycle control and apoptosis resistance. To discriminate between these different roles, we used transgenic expression of survivin in the skin as a model for cell proliferation, differentiation, and apoptosis. Transgenic mice expressing survivin under the control of a keratin-14 promoter developed normally, without histologic abnormalities of the skin or hair, epidermal hyperplasia, or developmental abnormalities of basal or suprabasal epidermis. Keratinocyte proliferation assessed under basal conditions, or after ultraviolet-B (UVB) irradiation, or phorbol ester stimulation was unchanged in survivin transgenic mice. In contrast, survivin expression inhibited UVB-induced apoptosis in vitro and in vivo (i.e., sunburn cell formation), whereas it did not affect Fas-induced cell death. When crossed with p53 knockout mice, transgenic expression of survivin in a p53(+/-) background substituted for the loss of a second p53 allele and further inhibited UVB-induced apoptosis. These data provide the first in vivo evidence that survivin inhibits apoptosis and suggest that this pathway may oppose the elimination of cancerous cells by p53.

Nuclear localization of beta-catenin is an important prognostic factor in hepatoblastoma

In this study, mutational and immunohistochemical analyses of beta-catenin were performed in 30 hepatoblastomas, to assess the prevalence of alterations of the Wnt pathway with respect to clinicopathological parameters and survival. Four missense mutations of beta-catenin (13.3%) were detected and there was strong immunoreactivity for beta-catenin in the cytoplasm and/or the nucleus in 97% of hepatoblastomas. Nuclear and cytoplasmic staining was demonstrated in 19 of 30 tumours (63%), while ten revealed only cytoplasmic staining. Statistically, this nuclear beta-catenin staining was significantly higher in the embryonal (Fisher exact test; p=0.00393) or undifferentiated type (p=0.00156) of hepatoblastoma than in the fetal type, but there was no difference between clinical stages I and II and clinical stages III and IV (p=0.175). Cumulative survival curves showed that nuclear beta-catenin staining (generalized Wilcoxon test; p=0.0088), undifferentiated histological type (p=0.0305), and clinical stages III and IV (p=0.0107) were significantly correlated with shorter survival time in these patients. Moreover, Cox multivariate analysis provides evidence that nuclear beta-catenin staining is the most important prognostic factor for survival (p=0.0090). It is therefore concluded that immunohistochemical analysis of beta-catenin might be a useful clinical tool for estimating the prognosis for patients with hepatoblastoma.

Somatic mutations in the death domain of the Fas (Apo-1/CD95) gene in gastric cancer

It is now believed that genes regulating apoptosis are also important variables in cancer development. Fas, a transmembrane protein of the tumour necrosis factor receptor family, is a key molecule for cell death signalling. The mutation of the primary structure of the Fas gene might also be one of the possible mechanisms that disrupt Fas-mediated apoptosis in tumour cells. The purpose of this study was to determine whether somatic mutation of the Fas gene could be involved in the tumourigenesis of gastric cancer. Polymerase chain reaction (PCR)-based loss of heterozygosity (LOH) analysis with two intragenic polymorphic markers, and mutation analysis for the entire coding regions of the Fas gene were performed in 43 cases of gastric cancer, using PCR-single-strand conformational polymorphism sequencing. Five (11.6%) missense mutations were detected, only in the death domain of the Fas gene. Although these mutations were observed only in intestinal-type gastric cancers, there was no statistically significant difference in the frequency of Fas mutation between intestinal- and diffuse-type gastric cancer (p=0.068). Nine LOH out of 22 informative cases were also detected with one or both markers (41%). Three of them demonstrated a somatic mutation in the remaining allele, indicating the inactivation of both alleles. These results suggest that genetic alterations of the Fas gene may not only be limited to gastric cancer cell protection through Fas resistance, but may also play an important role in tumour promotion and/or progression in a subset of gastric cancer.

Inhibition of melanoma tumor growth in vivo by survivin targeting

A role of apoptosis (programmed cell death) in tumor formation and growth was investigated by targeting the apoptosis inhibitor survivin in vivo. Expression of a phosphorylation-defective survivin mutant (Thr(34)-->Ala) triggered apoptosis in several human melanoma cell lines and enhanced cell death induced by the chemotherapeutic drug cisplatin in vitro. Conditional expression of survivin Thr(34)-->Ala in YUSAC2 melanoma cells prevented tumor formation upon s.c. injection into CB.17 severe combined immunodeficient-beige mice. When induced in established melanoma tumors, survivin Thr(34)-->Ala inhibited tumor growth by 60-70% and caused increased apoptosis and reduced proliferation of melanoma cells in vivo. Manipulation of the antiapoptotic pathway maintained by survivin may be beneficial for cancer therapy.

Fa1p is a 171 kDa protein essential for axonemal microtubule severing in Chlamydomonas

A key event in deflagellation or deciliation is the severing of the nine outer-doublet axonemal microtubules at a specific site in the flagellar transition zone. Previous genetic analysis revealed three genes that are essential for deflagellation in Chlamydomonas. We have now identified the first of these products, Fa1p, a protein required for Ca(2+)-dependent, axonemal microtubule severing. Genetic mapping and the availability of a tagged allele allowed us to physically map the gene to the centromere-proximal domain of the mating-type locus. We identified clones of Chlamydomonas genomic DNA that rescued the Ca(2+)-dependent axonemal microtubule severing defect of fa1 mutants. The FA1 cDNA, obtained by RT-PCR, encodes a novel protein of 171 kDa, which is predicted to contain an amino-terminal coiled-coil domain and three Ca(2+)/calmodulin binding domains. By western analysis and subcellular fractionation, the FA1 product is enriched in flagellar-basal body complexes. Based on these observations and previous studies, we hypothesize that a Ca(2+)-activated, Ca(2+)-binding protein binds Fa1p leading ultimately to the activation of axonemal microtubule severing.

Dexamethasone suppression of corticosteroid secretion: evaluation of the site of action by receptor measures and functional studies

A dose of dexamethasone was determined in rats (50 micrograms/kg s.c.) that suppressed the corticosterone response to restraint stress by 80%. Corticosteroid receptor occupancy estimates found that the 50 micrograms/kg s.c. dose of dexamethasone had no significant effect on available glucocorticoid receptor (GR) or mineralocorticoid receptor (MR) binding in brain regions (hypothalamus, hippocampus and cortex); on the other hand dexamethasone produced a selective and significant decrease in available GR in peripheral tissues (pituitary and spleen). Functional studies showed that the 50 micrograms/kg s.c. dose of dexamethasone completely blocked the effects of corticotropin-releasing hormone (CRH; 0.3-3.0 micrograms/kg i.p.) on corticosterone secretion, but did not inhibit the corticosterone response to an adrenocorticotropin hormone (ACTH; 2.5 I.U./kg i.p.) challenge. These studies indicate that this dose of dexamethasone exerts its inhibitory effects on the HPA axis primarily by acting at GR in the pituitary. The plasma dexamethasone levels produced by this dose of dexamethasone are similar to those present in humans the afternoon after an oral dexamethasone suppression test (DST), a time at which many depressed patients escape from dexamethasone suppression. These results support and extend other studies which suggest that the DST provides a direct test of the effects of increased GR activation in the pituitary on ACTH and cortisol secretion.

A distinct tumor suppressor gene locus on chromosome 15q21.1 in sporadic form of colorectal cancer

The SM1311 family is an Ashkenazi family with dominantly inherited predisposition to colorectal adenomas and carcinomas and has a high-penetrance locus in chromosome 15q, with a multipoint logarithm of the odds score of 3.06 at marker D15S118. In the present study, we performed a high-density loss of heterozygosity study with 13 polymorphic microsatellite markers, including D15S118, spanning 15q15.3-q22.1, on 70 cases of the sporadic form of colorectal tumors. Our deletion mapping data showed a locus at D15S968 in chromosomal sub-band 15q21.1 may harbor a tumor suppressor gene in an area <0.521 Mb in physical map distance defined by markers D15S514 and D15S222. THBS1, 0.185 Mb proximal to D15S968, is the nearest known gene to this specific narrow loss of heterozygosity region. Thus, we speculate that THBS1 might be the most probable candidate gene involved in colorectal cancer carcinogenesis.

A pilot study of 2 methods for control of dental unit biofilms

OBJECTIVE

This pilot study was conducted to clinically evaluate 2 different concentrations of sodium hypochlorite for the control of dental unit biofilms and to evaluate the efficacy of pasteurizing dental treatment water for patient care.

METHOD AND MATERIALS

Two dental units with no prior chemical treatment were retrofitted with self-contained water systems for this study. One dental unit was treated with 5,000 ppm of sodium hypochlorite and the other with 1,500 ppm. Treatment consisted of a 10-minute contact with the dental unit water lines, followed by a flush with a buffer solution. A pasteurizer was equipped with autoclavable spigots to provide dental treatment water. Heterotrophic Plate Count Samplers (Millipore) water sampler kits were used to quantify microbial contamination as absolute colony-forming units per millimeter. Scanning electron micrographs were taken of water line lumens to compare pretreatment and posttreatment biofilms.

RESULTS

Pasteurized water was significantly less contaminated than was tap water. No significant difference in contamination was found between the 5,000 ppm and 1,500 ppm treatment chairs, either in the reservoir water or effluent water. Scanning electron micrographs demonstrated removal of the biofilms after sodium hypochlorite treatments, regardless of the concentration used.

CONCLUSION

There was no significant difference between the abilities of 5,000- and 1,500-ppm concentrations of sodium hypochlorite to control contamination of dental treatment water and biofilms. Pasteurization of tap water can reduce contamination; this water can be used as acceptable dental treatment water (< 200 CFU/mL).

Frequent somatic mutations of the beta-catenin gene in intestinal-type gastric cancer

The increased level of cytoplasmic beta-catenin through the mutations to either beta-catenin or adenomatous polyposis coli (APC) has been proposed as an important oncogenic step in various tumors. Gastric cancer showed frequent genetic alterations of the APC gene, and the risk for gastric cancer in familial adenomatosus polyposis patients is 10 times higher than that in the general population. These findings raise the possibility that mutations of beta-catenin may also be associated with the development of gastric cancer. We detected seven somatic mutations in a portion of exon 3 encoding for the glycogen synthase kinase 3beta phosphorylation consensus region of the beta-catenin gene in 43 gastric cancers. All of these mutations were missense mutations, of which five are in the highly conserved aspartic acid 32 and two are in serine 29; all of these seven mutations were detected exclusively in intestinal-type gastric cancers (7 of 26; 26.9%), but not in the diffuse-type (0 of 17). We concluded that disruption of the APC/beta-catenin/T cell factor-lymphoid enhancer binding factor pathway might play an important role especially in the development of intestinal-type gastric cancer.

Evaluation of RU28318 and RU40555 as selective mineralocorticoid receptor and glucocorticoid receptor antagonists, respectively: receptor measures and functional studies

Corticosterone regulates a wide range of physiological parameters. Two receptors for corticosterone have been identified, the mineralocorticoid (type I) receptor (MR) and the glucocorticoid (type II) receptor (GR). To determine the relative role of these two receptors in mediating the effects of endogenous corticosterone, many studies have relied on the use of putative selective corticosteroid receptor antagonists. This study further examined the in vivo receptor selectivity of two compounds, RU28318 and RU40555 that are believed to be selective antagonists for MR and GR, respectively. Acute treatment of adrenalectomized rats with RU28318 (10-50 mg/kg) selectively decreased ex-vivo available MR binding in the hippocampus, whereas acute treatment with RU40555 (10-30 mg/kg) selectively decreased available GR binding in the hippocampus and pituitary. These receptor binding measures suggest that RU28318 in vivo selectively occupied MR, and that RU40555 in vivo selectively occupied GR. In functional studies, RU28318 (50 mg/kg) blocked the normalizing effect of aldosterone (120 microg/kg) on saline intake of adrenalectomized rats. RU40555 (30 mg/kg) blocked the suppressive effect of dexamethasone (50 microg/kg) on acute stress-induced corticosterone secretion. These studies further support the in vivo corticosteroid receptor selectivity of these two compounds and confirms their effective corticosteroid antagonistic properties.

Single unit recordings in the auditory nerve of congenitally deaf white cats: morphological correlates in the cochlea and cochlear nucleus

It is well known that experimentally induced cochlear damage produces structural, physiological, and biochemical alterations in neurons of the cochlear nucleus. In contrast, much less is known with respect to the naturally occurring cochlear pathology presented by congenital deafness. The present study attempts to relate organ of Corti structure and auditory nerve activity to the morphology of primary synaptic endings in the cochlear nucleus of congenitally deaf white cats. Our observations reveal that the amount of sound-evoked spike activity in auditory nerve fibers influences terminal morphology and synaptic structure in the anteroventral cochlear nucleus. Some white cats had no hearing. They exhibited severely reduced spontaneous activity and no sound-evoked activity in auditory nerve fibers. They had no recognizable organ of Corti, presented >90% loss of spiral ganglion cells, and displayed marked structural abnormalities of endbulbs of Held and their synapses. Other white cats had partial hearing and possessed auditory nerve fibers with a wide range of spontaneous activity but elevated sound-evoked thresholds (60-70 dB SPL). They also exhibited obvious abnormalities in the tectorial membrane, supporting cells, and Reissner's membrane throughout the cochlear duct and had complete inner and outer hair cell loss in the base. The spatial distribution of spiral ganglion cell loss correlated with the pattern of hair cell loss. Primary neurons of hearing-impaired cats displayed structural abnormalities of their endbulbs and synapses in the cochlear nucleus which were intermediate in form compared to normal and totally deaf cats. Changes in endbulb structure appear to correspond to relative levels of deafness. These data suggest that endbulb structure is significantly influenced by sound-evoked auditory nerve activity.

Colocalization of heparin and receptor binding sites on keratinocyte growth factor

Keratinocyte growth factor (KGF) is a member of the fibroblast growth factor (FGF) family. FGFs are also known as heparin-binding growth factors because they bind to heparin and their physical and biological properties are modulated by heparin. Consistent with a role as a paracrine effector, KGF is produced by cells of mesenchymal origin but is active primarily, if not exclusively, on epithelial cells. KGF is involved in a variety of physiological processes, including proliferation, differentiation, wound healing, and cytoprotection. To identify regions in KGF that contribute to heparin and tyrosine kinase receptor interactions, nine peptides spanning defined motifs in the predicted structure of KGF were synthesized, and their heparin and receptor binding properties were analyzed. Peptides at the amino and carboxyl termini bound heparin, and one peptide showed relative binding comparable to that of KGF. Competitive binding studies showed that this peptide along with two other overlapping peptides specifically displaced KGF bound to the KGF receptor. These three peptides were also selectively recognized by a neutralizing monoclonal antibody against KGF, though only in the presence of heparin. Together, these data suggest that the sites for heparin and receptor binding both reside in the amino and carboxyl termini of KGF, which are spatially juxtaposed in the predicted three-dimensional structure of this molecule.

Evidence for mineralocorticoid receptor facilitation of glucocorticoid receptor-dependent regulation of hypothalamic-pituitary-adrenal axis activity

These studies further evaluated the relative role of mineralocorticoid (type I) and glucocorticoid (type II) receptors in mediating corticosteroid feedback regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Acute treatment of rats with the selective mineralocorticoid receptor antagonist, RU28318 (50 mg/kg sc), produced elevated basal corticosterone levels in the morning, but had no effect on basal corticosterone levels in the evening or on restraint stress corticosterone levels at either time of day. Acute treatment with the selective glucocorticoid receptor antagonist, RU40555 (30 mg/kg sc) had no effect on basal or restraint stress corticosterone levels at either time of day. However, combined treatment with RU28318 and RU40555 produced an elevation of evening basal corticosterone levels (and morning basal on one occasion) and produced an increase in corticosterone levels during and after stress at both times of day. In a separate experiment conducted in the morning, the combined RU28318 and RU40555 treatment also produced elevated ACTH responses during restraint stress. Based on available corticosteroid receptor measures, the RU28318 treatment was estimated to selectively occupy approximately 85% of mineralocorticoid receptors in rat brain, whereas the RU40555 treatment was estimated to selectively occupy approximately 50% of glucocorticoid receptors in rat brain. We conclude that mineralocorticoid receptor activation is necessary and sufficient to maintain low basal corticosterone levels during the circadian trough, whereas glucocorticoid receptor activation is necessary to constrain corticosterone secretion during the circadian peak or during acute stress. However, even during the circadian peak or acute stress, mineralocorticoid receptor activation plays an important role in facilitating the glucocorticoid receptor dependent regulation of HPA axis activity by corticosterone.

Genetics of the deflagellation pathway in Chlamydomonas

Signal-induced deflagellation in Chlamydomonas involves Ca2+-activated breakage of the nine outer-doublet axonemal microtubules at a specific site in the flagellar transition zone. In this study, we isolated 13 new deflagellation mutants that can be divided into two phenotypic classes, the Adf class and the Fa class. Cells with the Adf deflagellation phenotype are defective in acid-stimulated Ca2+ influx, but can be induced to deflagellate by treatment with nonionic detergent and Ca2+. Genetic analyses show that the five new Adf mutations, as well as the previously identified adf1 mutation, are alleles of the ADF1 gene. Mutants in the second phenotypic class, the Fa mutants, fail to deflagellate in response to any known chemical stimulus and are defective in Ca2+-activated microtubule severing. Genetic analysis of these eight new Fa strains demonstrated that they define two complementation groups, and one of these contains the previously identified fa1 mutation. Diploid analysis showed that five alleles map to the FA1 gene, whereas four alleles define a novel gene that we have named FA2. The isolation of multiple mutant alleles of each gene, generated by either ultraviolet irradiation or insertional mutagenesis, indicates that ADF1, FA1, and FA2 may be the only genes that can be identified in a loss-of-function screen. These alleles should provide a better understanding of the regulation of microtubule severing by Ca2+.

Linear and nonlinear spectral integration in type IV neurons of the dorsal cochlear nucleus. II. Predicting responses with the use of nonlinear models

Two nonlinear modeling methods were used to characterize the input/output relationships of type IV units, which are one principal cell type in the dorsal cochlear nucleus (DCN). In both cases, the goal was to derive predictive models, i.e., models that could predict the responses to other stimuli. In one method, frequency integration was estimated from response maps derived from single tones and simultaneous pairs of tones presented over a range of frequencies. This model combined linear integration of energy across frequency and nonlinear interactions of energy at different frequencies. The model was used to predict responses to noisebands with varying width and center frequency. In almost all cases, predictions using two-tone interactions were better than linear predictions based on single-tone responses only. In about half the cases, reasonable quantitative fits were achieved. The fits were best for noisebands with narrow bandwidth and low sound levels. In the second nonlinear method, the spectrotemporal receptive field (STRF) was derived from responses to broadband stimuli. The STRF could account for some qualitative features of the responses to broad noisebands and spectral notches embedded in broad noisebands. Quantitatively, however, the STRFs failed to predict the responses of type IV units even to simple broadband noise stimuli. For narrowband stimuli, the STRF failed to predict even qualitative features (such as excitatory and inhibitory frequency bands). The responses of DCN type IV units presumably result from interactions of two inhibitory sources, a strong one that is preferentially activated by narrowband stimuli and a weaker one that is preferentially activated by broadband stimuli. The results presented here suggest that the STRF measures effects related to the broadband inhibition, whereas two-tone interactions measure mostly effects related to narrowband inhibition. This explains why models based on two-tone interactions predict the responses to narrow noisebands much better then models based on STRFs. It is concluded that a minimal stimulus set for characterizing type IV units must contain both broadband and narrowband stimuli, because each stimulus class by itself activates only partially the integration mechanisms that shape the responses of type IV units. Similar conclusions are expected to hold in other parts of the auditory system: when characterizing a complex auditory unit, it is necessary to use a range of stimuli to ensure that all integration mechanisms are activated.

4-hydroxy-2-nonenal pyrrole adducts in human neurodegenerative disease

Increasing age and inheritance of the epsilon 4 allele of apolipoprotein E (APOE4) are significant risk factors for sporadic and late onset familial Alzheimer disease (AD); however, the mechanisms by which either leads to AD are unknown. Numerous studies have associated advancing age with increased indices of oxidative challenge to brain, and with still further increased oxidative damage to relevant brain regions in AD patients. A major consequence of oxidative damage to brain is lipid peroxidation with production of the neurotoxic metabolite 4-hydroxy-2-nonenal (HNE). HNE reacts with protein to yield several adducts, including a pyrrole adduct that forms irreversibly in biological systems. Previously, we have shown in a small number of AD and control patients that HNE pyrrole adduct antiserum is immunoreactive with neurofibrillary tangles (NFT), and that this reactivity was significantly associated with inheritance of APOE4. Others have confirmed this pattern of immunoreactivity in AD brain but did not observe an association with APOE4. Herein, we have expanded the study group to 19 AD patients homozygous for APOE4 or APOE3, as well as 30 patients with other neurodegenerative diseases, including diffuse Lewy body disease, Pick's disease, progressive supranuclear palsy, Parkinson's disease, and human immunodeficiency virus-1 encephalitis. HNE pyrrole adduct immunoreactivity on NFT in AD patients was strongly associated with APOE4 homozygosity. With the exception of rare immunoreactive Pick bodies in one case of Pick's disease, no other structure was recognized by HNE pyrrole adduct antiserum in this series of patients. We propose that there is a significant difference between the interaction of apoE3 and apoE4 with lipid peroxidation in the brains of AD patients.

Diazepam attenuation of restraint stress-induced corticosterone levels is enhanced by prior exposure to repeated restraint

Prior research has demonstrated that diazepam decreases hypothalamic-pituitary-adrenal cortex (HPA) axis activity in stressful contexts but, paradoxically, acts as a stimulator of basal axis activity. Also, several investigators have reported that low doses of diazepam are not effective in reducing stress-induced corticosterone (CORT) levels, yet similar doses typically produce anxiolytic effects on behavioral measures of fear and anxiety. We have examined the effects of diazepam on plasma CORT levels in male Sprague-Dawley rats utilizing a repeated restraint paradigm. Consistent with most literature, diazepam administered IP (1.5, 3.0, or 6.0 mg/kg) 1 h prior to restraint increased non-stress, baseline plasma CORT levels in a dose-dependent fashion. During the first exposure to the 1 h restraint-stress procedure, CORT levels of diazepam-injected rats did not differ from the stress levels of controls except at the 60-min stress time point in those subjects receiving 6.0 mg/kg. However, diazepam at all three doses was able to attenuate the stress-induced increase in CORT following 5 days of diazepam+restraint treatment. Using the 3.0 mg/kg dose as a probe, it was found that this effect was not dependent on the repeated administration of diazepam, but rather on repeated exposure to restraint. These results suggest that repeated restraint produces a change in neural sensitivity to benzodiazepines.

Comparative analysis of spectro-temporal receptive fields, reverse correlation functions, and frequency tuning curves of auditory-nerve fibers

The tuning properties of single auditory-nerve fibers (ANFs) are characterized with spectro-temporal receptive fields (STRFs), reverse correlation functions (revcors), and frequency tuning curves (FTCs). Measures of tuning and latency from the STRFs and revcors are largely comparable to the traditional measures of tuning from FTCs and measures of latency from peristimulus time histograms (PSTHs), but several important differences are found. As is well known, revcors can only characterize low (< 6 kHz) best frequency (BF) units, whereas STRFs are able to characterize all units studied (BFs ranging from 0.26-23 kHz), except for a few very low-BF examples. Whereas tuning bandwidth derived from revcor exceeds that measured from FTCs at all BFs and increases with sound level. STRF bandwidth is comparable to FTC bandwidth, except at low BFs, and is stable with sound level. The STRF may reflect nonlinear properties of auditory-nerve fibers such as refractoriness and two-tone suppression that are absent in the FTC and revcor characterizations. The principal drawback of the STRF is its narrow dynamic range.

Judgment error in category vs magnitude scales

The effects of a variety of experimental conditions on the judgments (length of lines) of 16 normal and 16 mentally retarded observers were examined using category and magnitude scaling techniques. Using error and variability of judgment as criteria for measuring response bias, for normal subjects knowledge about the stimulus range, whether learned or provided, had as much to do with resulting judgments as the type of scale used. Judgment error of the retarded group was significantly greater than the normal group and appeared to be related to their limited ability to assign categories or proportions to the simuli used.