bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of Glia Number in Drosophila by Rap/Fzr, an Activator of the Anaphase-Promoting Complex, and Loco, an RGS Protein
Authors: Kaplow Margarita E , Korayem Adam H , Venkatesh Tadmiri R
Published: April 2008

Glia mediate a vast array of cellular processes and are critical for nervous system development and function. Despite their immense importance in neurobiology, glia remain understudied and the molecular mechanisms that direct their differentiation are poorly understood. Rap/Fzr is the Drosophila homolog of the mammalian Cdh1, a regulatory subunit of the anaphase-promoting complex/cyclosome (APC/C). APC/C is an E3 ubiquitin ligase complex well characterized for its role in cell cycle progression. In this study, we have uncovered a novel cellular role for Rap/Fzr. Loss of rap/fzr function leads to a marked increase in the number of glia in the nervous system of third instar larvae. Conversely, ectopic expression of UAS-rap/fzr, driven by repo-GAL4, results in the drastic reduction of glia. Data from clonal analyses using the MARCM technique show that Rap/Fzr regulates the differentiation of surface glia in the developing larval nervous system. Our genetic and biochemical data further indicate that Rap/Fzr regulates glial differentiation through its interaction with Loco, a regulator of G-protein signaling (RGS) protein and a known effector of glia specification. We propose that Rap/Fzr targets Loco for ubiquitination, thereby regulating glial differentiation in the developing nervous system.
Multiple Rescue Factors Within a Wolbachia Strain
Authors: Zabalou Sofia , Apostolaki Angeliki , Pattas Savvas , Veneti Zoe , Paraskevopoulos Charalampos , Livadaras Ioannis , Markakis George , Brissac Terry , Merçot Hervé , Bourtzis Kostas
Published: April 2008

Wolbachia-induced cytoplasmic incompatibility (CI) is expressed when infected males are crossed with either uninfected females or females infected with Wolbachia of different CI specificity. In diploid insects, CI results in embryonic mortality, apparently due to the the loss of the paternal set of chromosomes, usually during the first mitotic division. The molecular basis of CI has not been determined yet; however, several lines of evidence suggest that Wolbachia exhibits two distinct sex-dependent functions: in males, Wolbachia somehow “imprints” the paternal chromosomes during spermatogenesis (mod function), whereas in females, the presence of the same Wolbachia strain(s) is able to restore embryonic viability (resc function). On the basis of the ability of Wolbachia to induce the modification and/or rescue functions in a given host, each bacterial strain can be classified as belonging in one of the four following categories: mod+  resc+, mod−  resc+, mod−  resc−, and mod+  resc−. A so-called “suicide” mod+  resc− strain has not been found in nature yet. Here, a combination of embryonic cytoplasmic injections and introgression experiments was used to transfer nine evolutionary, distantly related Wolbachia strains (wYak, wTei, wSan, wRi, wMel, wHa, wAu, wNo, and wMa) into the same host background, that of Drosophila simulans (STCP strain), a highly permissive host for CI expression. We initially characterized the modification and rescue properties of the Wolbachia strains wYak, wTei, and wSan, naturally present in the yakuba complex, upon their transfer into D. simulans. Confocal microscopy and multilocus sequencing typing (MLST) analysis were also employed for the evaluation of the CI properties. We also tested the compatibility relationships of wYak, wTei, and wSan with all other Wolbachia infections. So far, the cytoplasmic incompatibility properties of different Wolbachia variants are explained assuming a single pair of modification and rescue factors specific to each variant. This study shows that a given Wolbachia variant can possess multiple rescue determinants corresponding to different CI systems. In addition, our results: (a) suggest that wTei appears to behave in D. simulans as a suicide mod+ resc− strain, (b) unravel unique CI properties, and (c) provide a framework to understand the diversity and the evolution of new CI-compatibility types.
Epigenetic Control May Explain Large Within-Plant Heterogeneity of Meiotic Behavior in Telocentric Trisomics of Rye
Authors: Sybenga J , Verhaar H , Botje D G A
Published: April 2008

In telocentric trisomics (telotrisomics) of organisms in which the chromosomes normally have two distinct arms, a single chromosome arm with a centromere is present in addition to a complete diploid set of chromosomes. It is the simplest form of polysomy and suitable for analyzing meiotic pairing and recombination patterns in situations where chromosomes compete for pairing. When no suitable meiotic chromosome markers are available, four metaphase I configurations can be distinguished. Their relative frequencies are indicative of the pairing and recombination patterns. In short arm (1RS) telotrisomics of chromosome 1R of rye (Secale cereale) we observed great differences in pairing and recombination patterns among spikes from different tillers and clones of the same plants. Anthers within spikes were only very rarely different. We analyzed a large number of genotypes, including inbreds as well as hybrids. The effects of genetic and environmental conditions on heterogeneity, if any, were limited. Considering that the reproductive tissue of a spike is derived from one primordial cell, it seems that at the start of sexual differentiation there was variation among cells in chromosomal control, which at meiosis determines pairing and crossing-over competence. We suggest that it is an epigenetic system that rigidly maintains this pattern through generative differentiation. In competitive situations the combination most competent for pairing will pair preferentially, forming specific meiotic configurations with different frequencies for different spikes of the same plant. This would explain the heterogeneity between spikes and the homogeneity within spikes. The epigenetic system could involve chromatin conformation or DNA methylation. There were no signs of heterochromatinization.
Erythroid Apoptosis in Idiopathic Neonatal Jaundice
Authors: Özkan Hasan , Ören Hale , Tatlı Mansur , Ateş Halil , Kumral Abdullah , Duman Nuray
Published: April 2008

OBJECTIVES. The objectives of this study were to evaluate the contribution of erythroid apoptosis to neonatal idiopathic pathologic jaundice and to determine whether a measurement of the erythroid apoptosis value at birth could predict the development of hyperbilirubinemia during the first 15 days of life.

PATIENTS AND METHODS. Three groups were defined: group 1 (n = 101), healthy newborns whose erythroid apoptosis value and serum total bilirubin levels were detected from birth to day 15; group 2 (n = 24), newborns who were hospitalized for jaundice (serum total bilirubin level: >12.9 mg/dL) without any identifiable pathologic cause; and group 3 (control group, n = 24), healthy newborns whose serum total bilirubin levels were ≤12.9 mg/dL. Erythroid apoptosis value was assessed by flow cytometry using an annexin-V fluorescein isothiocyanate kit.

RESULTS. In group 1, there was no correlation between the erythroid apoptosis value and serum total bilirubin levels obtained at birth and at the fourth and 15th days of life; the erythrocyte apoptosis value obtained at birth was not significantly different between the neonates whose serum total bilirubin levels were >12.9 and ≤12.9 mg/dL and who had prolonged and nonprolonged jaundice during follow-up. The erythroid apoptosis value differed significantly between the newborns in groups 2 and 3. There was no significant correlation between the erythroid apoptosis value and serum total bilirubin levels of the infants in groups 2 and 3.

CONCLUSIONS. The erythroid apoptosis value obtained at birth could not predict the development of hyperbilirubinemia in neonates, but it was increased significantly in jaundiced neonates whose serum total bilirubin levels were >12.9 mg/dL. In these infants, increase in the erythroid apoptosis value may be a result of the toxic effect of bilirubin or of a protective mechanism of neonates to increase heme turnover and bilirubin production to diminish oxidative stress.
Embryonic Stem Cells as a Platform for Analyzing Neural Gene Transcription
Authors: Zhang Xiaodong , Horrell Scott A. , Delaney Deany , Gottlieb David I.
Published: April 2008

There is a need for improved methods to analyze transcriptional control of mammalian stem cell genes. We propose that embryonic stem cells (ESCs) will have broad utility as a model system, because they can be manipulated genetically and then differentiated into many cell types in vitro, avoiding the need to make mice. Results are presented demonstrating the utility of ESCs for analyzing cis-acting sequences using Olig2 as a model gene. Olig2 is a transcription factor that plays a key role in the development of a ventral compartment of the nervous system and the oligodendrocyte lineage. The functional role of an upstream region (USR) of the Olig2 gene was investigated in ESCs engineered at the undifferentiated stage and then differentiated into ventral neural cells with sonic hedgehog and retinoic acid. Deletion of the USR from the native gene via gene targeting eliminates expression in ventral neural cells differentiated in cell culture. The USR is also essential for regulated expression of an Olig2 transgene inserted at a defined foreign chromosomal site. A subregion of the USR has nonspecific promoter activity in transient transfection assays in cells that do not express Olig2. Taken together, the data demonstrate that the USR contains a promoter for the Olig2 gene and suggest that repression contributes to specific expression. The technology used in this study can be applied to a wide range of genes and cell types and will facilitate research on cis-acting DNA elements of mammalian genes.

Disclosure of potential conflicts of interest is found at the end of this article.
Water environment improvements in Zhenjiang City, China
Authors: Tang H. , Lu S. , Zhou Y. , Xu X. , Xiao Y.
Published: April 2008

The Neijiang River is the main water body in Zhenjiang City, a medium-sized city in the east of China, located in the Yangtze River delta. With the long-term aim of improving water quality and restoring the aquatic ecosystem of Zhenjiang City, integrated physical and numerical modelling of the Neijiang River was carried out. A series of engineering measures was proposed based on modelling results. The first is the construction of a sluice and pumping station near the inlet of the main course of water passage, that is, the navigation channel. The second proposal is to build desilting basins on both sides of the sluice/pumping station. Results of physical experiments indicate that the sluice/pumping station can effectively regulate water exchange between the Neijiang and Yangtze Rivers and reduce seasonal water level fluctuations of the Neijiang River. Large quantities of sediment accumulate in the two desilting basins, resulting in obvious increases in river water transparency. Other measures proposed are a vegetated dam downstream of the second desilting basin and new ecotypic banks inside the Neijiang River and urban rivers. Newly planted vegetation on the vegetated dam and riverbanks has already greatly enhanced the self-purification capacity of the Neijiang River while naturally maintaining the city landscape.
Circulating Retinol-Binding Protein-4 Concentration Might Reflect Insulin Resistance–Associated Iron Overload
Authors: Fernández-Real José Manuel , Moreno José María , Ricart Wifredo
Published: April 2008

OBJECTIVES—The mechanisms behind the association between retinol-binding protein-4 (RBP4) and insulin resistance are not well understood. An interaction between iron and vitamin A status, of which RBP4 is a surrogate, has long been recognized. We hypothesized that iron-associated insulin resistance could be behind the impaired insulin action caused by RBP4.

RESEARCH DESIGN AND METHODS—Serum ferritin and RBP4 concentration and insulin resistance were evaluated in a sample of middle-aged men (n = 132) and in a replication independent study. Serum RBP4 was also studied before and after iron depletion in patients with type 2 diabetes. Finally, the effect of iron on RBP4 release was evaluated in vitro in adipose tissue.

RESULTS—A positive correlation between circulating RBP4 and log serum ferritin (r = 0.35 and r = 0.61, respectively; P < 0.0001) was observed in both independent studies. Serum RBP4 concentration was higher in men than women in parallel to increased ferritin levels. On multiple regression analyses to predict serum RBP4, log serum ferritin contributed significantly to RBP4 variance after controlling for BMI, age, and homeostasis model assessment value. Serum RBP4 concentration decreased after iron depletion in type 2 diabetic patients (percent mean difference −13.7 [95% CI −25.4 to −2.04]; P = 0.024). The iron donor lactoferrin led to increased dose-dependent adipose tissue release of RBP4 (2.4-fold, P = 0.005) and increased RBP4 expression, while apotransferrin and deferoxamine led to decreased RBP4 release.

CONCLUSIONS—The relationship between circulating RBP4 and iron stores, both cross-sectional and after iron depletion, and in vitro findings suggest that iron could play a role in the RBP4–insulin resistance relationship.
Association Analysis of Type 2 Diabetes Loci in Type 1 Diabetes
Authors: Qu Hui-Qi , Grant Struan F.A. , Bradfield Jonathan P. , Kim Cecilia , Frackelton Edward , Hakonarson Hakon , Polychronakos Constantin
Published: April 2008

OBJECTIVE—To search for a possible association of type 1 diabetes with 10 validated type 2 diabetes loci, i.e., PPARG, KCNJ11, WFS1, HNF1B, IDE/HHEX, SLC30A8, CDKAL1, CDKN2A/B, IGF2BP2, and FTO/RPGRIP1L.

RESEARCH DESIGN AND METHODS—Two European population samples were studied: 1) one case-control cohort of 514 type 1 diabetic subjects and 2,027 control subjects and 2) one family cohort of 483 complete type 1 diabetic case-parent trios (total 997 affected). A total of 13 tag single nucleotide polymorphisms (SNPs) from the 10 type 2 diabetes loci were analyzed for type 1 diabetes association.

RESULTS—No association of type 1 diabetes was found with any of the 10 type 2 diabetes loci, and no age-at-onset effect was detected. By combined analysis using the Wellcome Trust Case-Control Consortium type 1 diabetes data, SNP rs1412829 in the CDKN2A/B locus bordered on significance (P = 0.039) (odds ratio 0.929 [95% CI 0.867–0.995]), which did not reach the statistical significance threshold adjusted for 13 tests (α = 0.00385).

CONCLUSIONS—This study suggests that the type 2 diabetes loci do not play any obvious role in type 1 diabetes genetic susceptibility. The distinct molecular mechanisms of the two diseases highlighted the importance of differentiation diagnosis and different treatment principles.
New data on the variation of laser induced retinal-damage threshold with retinal image size
Authors: Zuclich J. A. , Edsall P. E. , Lund D. J. , Stuck B. E. , Till S. , Hollins R. C. , Kennedy P. K. , McLin L. N.
Published: April 2008

In earlier studies, we examined the dependence of the laser induced retinal damage threshold on retinal image size for extended-source ocular exposures. We reported the spot-size dependence of the retinal threshold (based on ophthalmic observations at 24 h postexposure) for two pulsewidth regimes: nanosecond-duration (Q-switched) pulses from a doubled Nd:yttrium–aluminum–garnet laser and microsecond-duration pulses from a flashlamp-pumped dye laser at 590 nm. In either case, the retinal threshold was shown to vary with the area (i.e., diameter squared) for image diameters >5 mrad. More recently, we have collected additional data for the intermediate spot-size range (1.5–10 mrad) and have compared both the absolute values and the spot-size trend of retinal thresholds determined via ophthalmoscopic observation at 1 h postexposure to the analogous threshold data collected with observations at 24 h postexposure. These additional data and analyses reinforce our earlier conclusions regarding the threshold vs. spot-size trend and are compared to and reconciled with results from previously published extended-source ocular damage studies. The experimental spot-size trends are also contrasted to the existing laser safety standard treatments of maximum permissible exposure levels for extended-source ocular exposures.
Review of exposure limits and experimental data for corneal and lenticular damage from short pulsed UV and IR laser radiation
Authors: Schulmeister Karl , Sliney David H. , Mellerio John , Lund David J. , Stuck Bruce E. , Zuclich Joseph A.
Published: April 2008

Laser exposure limits as promulgated by the International Commission on Non-Ionizing Radiation Protection are compared to relevant experimental animal injury data for cornea and lens exposure in the nanosecond to microsecond pulse duration regime in both the ultraviolet (UV) and infrared spectral ranges. In the UV spectral range, thermal and photochemical damage mechanisms compete and thresholds must be carefully distinguished as a function of wavelength and pulse duration. The thermal UV damage data are compared with levels inferred from CO2 radiation thresholds and it is shown that the reduction factors between experimental data for thermal injury and the corresponding exposure limits appear to be unnecessarily high. The lack of data for nanosecond exposures for wavelengths below 355 nm is identified. Available experimental data for infrared radiation (1.4–4 μm) can be fitted well with an inverse-absorption curve for saline. The exposure limits roughly follow the absorption curve with a varying degree of safety scaling factor. A lack of experimental threshold data is identified for wavelengths around the 3 μm absorption peak for water absorption. The inverse curve for the spectral absorption of water would suggest a rather low threshold for a biological effect at 3 μm.
Effectiveness of Biocontrol Based IPM Modules Against Lipaphis Erysimi Kaltenbach (Hemiptera: Aphididae)
Authors: Pandey Rakesh , Singh Narendra
Published: April 2008

Effectiveness of Biocontrol Based IPM Modules Against Lipaphis Erysimi Kaltenbach (Hemiptera: Aphididae)

Rapessed and mustard are important oilseed crops in India. The vulnerability of the crop to mustard aphid,Lipaphis erysimiKaltenbach is the main bottleneck in successful cultivation of this crop. In order to use insecticides at a minimum level, effectiveness of different Integrated Pest Management (IPM) modules were tested under field conditions. The module (NSKE +Chrysoperla carnea) proved most effective in reducing the aphid population in terms of socio-economic and environmental values.
The Problems of Weed Management by Herbicide Systems Applied in Maize
Authors: Gołebiowska Hanna
Published: April 2008

The Problems of Weed Management by Herbicide Systems Applied in Maize

Detailed recognition of weed infestation state and degree in south-western region of Poland provided the basis for starting field experiment on three types of soils aiming at the assessment of weed control effectiveness by means of suitably selected herbicide systems. High efficiency of weed elimination on alluvial soils was obtained due to herbicide mixture mesotrione + nicosulfuron in split doses. In the experiment established on brown soils the mentioned weed species were most satisfactorily controlled by herbicide mixture applied according to infestation degree: mesotrione + nicosulfuron i rimsulfuron + adjuvant + dicamba applied once in full doses. The mixture rimsulfuron + adjuvant + dicamba showed to be the most efficient regarding the weeds typical for alluvial soils, except for Elymus repens, numerously occurring in the experiment, which exhibited medium sesitivity, as well as winter forms of Anthemis arvensis. Mixture of rimsulfuron + adjuvant + florasulam + 2,4- D allowed to eliminate undesired plants on that soil stand in the most efficient way and to achieve the highest grain yield.
Book Review Buntin G. D., Pike K. S., Weiss M. J., Webster J. A. 2007. (Eds.). Handbook of Small Grain Insects. Published jointly by the Entomological Society of America, Lanham, MD and the American Phytopathological Society, St. Paul, MN, USA. ISBN 978-0-9776209-1-3 & ISBN 780977-602913.
Authors: Lipa Jerzy
Published: April 2008

Book Review Buntin G. D., Pike K. S., Weiss M. J., Webster J. A. 2007. (Eds.). Handbook of Small Grain Insects. Published jointly by the Entomological Society of America, Lanham, MD and the American Phytopathological Society, St. Paul, MN, USA. ISBN 978-0-9776209-1-3 & ISBN 780977-602913.
Performance of Musicians and Nonmusicians on Dichotic Chords, Dichotic CVs, and Dichotic Digits
Authors: Nelson Dawn M. , Wilson Richard H. , Kornhass Suzanne
Published: April 2008

Perception of dichotic chords (free recall and directed recall), nonsense syllables (CVs), and three-pair digits was assessed on 24 musicians and 24 nonmusicians. On the dichotic-CV and dichotic-digit free-recall tasks, there was a significant right-ear advantage, but there were no
group differences. With the dichotic-chords, free-recall condition, a significant left-ear advantage was observed but no group difference. For the dichotic-chords, directed-recall conditions, the musicians performed significantly better by 10 percent than the nonmusicians. Unexpectedly, for
the dichotic chords, the 62–72 percent correct performances were better on the free-recall condition than the 42–55 percent performances on the directed-recall conditions. These differences between the two response modes were attributed to the difficulty of the dichotic-chord listening
tasks and the probabilities associated with the closed-set response paradigms. The findings suggest that the dichotic-chord paradigm used in this study should not be included in clinical protocols used to assess auditory perceptual abilities. La percepción de acordes dicóticos
(evocación libre y evocación dirigida), de sílabas sin sentido (CV) y de dígitos de tres pares fue evaluada por 24 músicos y 24 no músicos. En las tareas de sílabas dicóticas sin sentido y en evocación libre para dígitos
dicóticos, existió una ventaja significativa del oído derecho, pero no ocurrieron diferencias de grupo. Con los acordes dicóticos, en la condición de evocación libre, se observó una ventaja significativa del oído izquierdo, pero no existió
una diferencia de grupo. Para los acordes dicóticos, en la condición de evocación dirigida, los músicos rindieron significativamente mejor que los no músicos (diferencia del 10%). Inesperadamente, para los acordes dicóticos, el 62-72% de respuestas
correctas fue mejor para la condición de evocación libre, que el 45-55% de respuestas en la condición de evocación dirigida. Estas diferencias entre los dos modos de respuesta se atribuyen a la dificultad de las tareas de captación de los acordes dicóticos
y a las probabilidades asociadas a los paradigmas de respuesta de lista cerrada. Los hallazgos sugieren que el paradigma de acordes dicóticos utilizado en este estudio debería ser incluido en los protocolos clínicos usados para evaluar las capacidades perceptivas auditivas.
Normal Brief-Tone Bone-Conduction Behavioral Thresholds Using the B-71 Transducer: Three Occlusion Conditions
Authors: Small Susan A. , Stapells David R.
Published: April 2008

Behavioral thresholds were measured from 31 adults with normal hearing for 500, 1000, 2000, and 4000 Hz brief tones presented using a B-71 bone oscillator. Three occlusion conditions were assessed: ears unoccluded, one ear occluded, and both ears occluded. Mean threshold force levels
were 67, 54, 49, and 41 dB re:1μN peak-to-peak equivalent in the unoccluded condition for 500, 1000, 2000, and 4000 Hz, respectively (corrected for air-conduction pure-tone thresholds). A significant occlusion effect was observed for 500 and 1000 Hz stimuli. These thresholds may be used
as the 0 dB nHL (normalhearing level) for brief-tone bone-conduction stimuli for auditory brainstem response testing. Se midieron los umbrales conductuales de 31 adultos con audición normal para tonos breves en 500, 1000, 2000, y 4000 Hz, presentados utilizando un oscilador óseo
B-71. Se evaluaron tres condiciones de oclusión: oídos no ocluidos, un oído ocluido, y ambos oídos ocluidos. Los niveles de fuerza umbral promedio para 500, 1000, 2000 y 4000 Hz (corregidos para umbrales tonales puros por vía aérea) fueron 67, 54,
49 y 41 dB re:1μN pico-a-pico equivalente en la condición no ocluida, respectivamente. Un efecto significativo de oclusión fue observado en los estímulos de 500 y 1000 Hz. Estos umbrales pueden ser utilizados como el 0 dB nHL (nivel auditivo normal) para estímulos
de tono breve por conducción ósea en estudios de respuestas auditivas del tallo cerebral.
Transient Evoked Otoacoustic Emissions in Adults: A Comparison between Two Test Protocols
Authors: Kei Joseph , Sockalingam Ravi , Holloway Clive , Agyik Alan , Brinin Craig , Baine Doreen
Published: April 2008

This study compares the performance of the Quickscreen and Default protocols of the ILO-96 Otodynamics Analyzer in recording transient evoked otoacoustic emissions (TEOAEs) from adults using clinical decision analysis. Data were collected from 25 males (mean age = 29.0 years, SD = 6.8)
and 35 females (mean age = 28.1 years, SD = 9.6). The results showed that the mean signal-to-noise ratios obtained from the Quickscreen were significantly greater than those from the Default protocol at 1, 2, and 4 kHz. The comparison of the performance of the two protocols, based on the results
using receiver operating characteristics curves, revealed a higher performance of the Quickscreen than the Default protocol at 1 and 4 kHz but not at 2 kHz. In view of the enhanced performance of the Quickscreen over the Default protocol in general, the routine use of the Default protocol
for testing adults in audiology clinics should be reconsidered. Este estudio compara el rendimiento del protocolo Quickscreen y el predeterminado (default) en el Analizador Otodynamics ILO-96, para registrar emisiones otoacústicas evocadas por transientes (TEOAE) en adultos, utilizando
análisis de decisión clínica. Se recogió información de 25 hombres (edad media = 29.0 años, DS = 6.8) y 35 mujeres (edad media = 28.1 años, DS = 9.6). Los resultados mostraron que las relaciones señal/ruido medias obtenidas del Quickscreen
fueron significativamente mayores que las del protocolo predeterminado, en 1, 2 y 4 kHz. La comparación del rendimiento de los dos protocolos, basado en los resultados generados a partir de curvas características de receptor operante, reveló un rendimiento mayor del protocolo
Quickscreen sobre el protocolo predeterminado en 1 y 4 kHz, pero no en 2 kHz. En vista del rendimiento aumentado del protocolo Quickscreen sobre el protocolo predeterminado en general, debería reconsiderarse el uso rutinario del protocolo predeterminado en la evaluación de adultos
en las clínicas audiológicas.
Interactions of Hearing Aid Compression Release Time and Fitting Formula: Effects on Speech Acoustics
Authors: Ellison John C. , Harris Frances P. , Muller Thomas
Published: April 2008

The effects of the interaction of compression release time and prescribed gain on running speech processed through a hearing aid on KEMAR was investigated. A digital instrument was programmed to fit a mild to moderate sloping hearing loss using probe microphone measures to reach targets
prescribed by NAL-NL1, DSL I/O, FIG.6 or ASA2p with release times of 40 and 640 ms for each condition. Recordings were made through KEMAR and analyzed to determine the long-term-average-speech spectra, consonant-to-vowel ratios and the RMS amplitude of 32 phonemic units. Aided and unaided
results were compared. Within each prescriptive formula, changes in release time affected all of the speech measures subsequent to programming the instrument to a static-composite signal. The short release-time condition produced the greatest alteration to the speech signal. Release time may
need consideration when fitting hearing aids to target gain prescriptions. Se investigaron los efectos de la integración del tiempo de liberación de la compresión (compression release time) y de la ganancia prescrita, utilizando lenguaje corrido a través de un auxiliar
auditivo en el KEMAR. Un dispositivo digital fue programado para amplificar una hipoacusia leve a moderada con pendiente progresiva, utilizando medidas de un micrófono de prueba que alcanzaran los objetivos indicados en NAL-NL1, DSL I/O, FIG.6, ASA2P, con tiempos de liberación
de 40 a 640 ms para cada condición. Los registros se realizaron a través del KEMAR y fueron analizados para determinar los espectros promedio a largo plazo del lenguaje, las tasa consonante/vocal y la amplitud RMS de 32 unidades fonémicas. Se compararon los resultados
con y sin amplificación. Dentro de cada fórmula de prescripción, los cambios en el tiempo de liberación afectaron todas las medidas de lenguaje, luego de programar el instrumento para una señal estática-compuesta. La condición de tiempo de liberación
corto produjo la mayor alteración de la señal de lenguaje. El tiempo de liberación debería ser tomado en cuenta cuando se ajuste un auxiliar auditivo para alcanzar una ganancia de prescripción.
Evidence of Acclimatization in Persons with Severe-to-Profound Hearing Loss
Authors: Kuk Francis K. , Potts Lisa , Valente Michael , Lee Lidia , Picirrillo Jay
Published: April 2008

The present study examined the phenomenon of acclimatization in persons with a severe-to-profound hearing loss. A secondary purpose was to examine the efficacy of a digital nonlinear power hearing aid that has a low compression threshold with expansion for this population. Twenty experienced
hearing aid users wore the study hearing aids for three months and their performance with the study hearing aids was evaluated at the initial fitting, one month, and three months after the initial fitting. Performance of their current hearing aids was also evaluated at the initial fitting.
Speech recognition testing was conducted at input levels of 50 dB SPL and 65 dB SPL in quiet, and 75 dB SPL in noise at a +10 SNR. Questionnaires were used to measure subjective performance at each evaluation interval. The results showed improvement in speech recognition score at the one-month
evaluation over the initial evaluation. No significant improvement was seen at the three-month evaluation from the one-month visit. In addition, subjective and objective performance of the study hearing aids was significantly better than the participants' own hearing aids at all evaluation
intervals. These results provided evidence of acclimatization in persons with a severe-to-profound hearing loss and reinforced the precaution that any trial of amplification, especially from linear to nonlinear mode, should consider this phenomenon. El presente estudio examina el efecto de
la climatización en personas con hipoacusia severas a profundas. Un propósito secundario fue examinar la eficacia de un auxiliar auditivo potente, digital, no lineal, con un umbral de compresión bajo, pero con expansión para esta población. Veinte usuarios
con experiencia con audífonos utilizaron el auxiliar audítivo del estudio por tres meses y su rendimiento con el audífono del estudio se evaluó en la adaptación inicial, al mes y a los tres meses posteriores a la adaptación. El rendimiento de su auxiliar
auditivo original fue evaluado también al inicio. Se condujeron pruebas de reconocimiento del lenguaje a niveles de 50 dB SPL y a 65 dB SPL, en silencio, y a 75 dB SPL en ruido, con un SNR de + 10. Se utilizaron cuestionarios para medir el rendimiento subjetivo en cad a intervalo de
evaluación. Los resultados mostraron una mejoría en los puntajes de reconocimiento del lenguaje en la evaluación del primer mes, comparados con los iniciales. No se observó ninguna mejoria significativa en la evaluación a los tres meses, comparada con la
visita del primer mes. Además, el rendimiento subjetivo y objetivo del audífono del estudio fue significativamente mejor que el del propio audífono de los participantes, en todos los intervalos de evaluación. Estos resultados móstraron evidencia de la climatización
en personas con hipoacusias severas a profundas, y reafirmó la precaución que debe tenerse en cualquier estudio de amplificación, sobre todo del modo lineal al no lineal, debiendo considerarse este fenómeno.
The Effects of Click and Tone-Burst Stimulus Parameters on the Vestibular Evoked Myogenic Potential (VEMP)
Authors: Akin Faith Wurm , Murnane Owen D. , Proffitt Tina M.
Published: April 2008

Vestibular evoked myogenic potentials (VEMP) are short latency electromyograms (EMG) evoked by high-level acoustic stimuli and recorded from surface electrodes over the tonically contracted sternocleidomastoid (SCM) muscle and are presumed to originate in the saccule. The present experiments
examined the effects of click and tone-burst level and stimulus frequency on the latency, amplitude, and threshold of the VEMP in subjects with normal hearing sensitivity and no history of vestibular disease. VEMPs were recorded in all subjects using 100 dB nHL click stimuli. Most subjects
had VEMPs present at 500, 750, and 1000 Hz, and few subjects had VEMPs present at 2000 Hz. The response amplitude of the VEMP increased with click and tone-burst level, whereas VEMP latency was not influenced by the stimulus level. The largest tone-burst-evoked VEMPs and lowest thresholds
were obtained at 500 and 750 Hz. VEMP latency was independent of stimulus frequency when tone-burst duration was held constant. Los potenciales evocados miogénicos vestibulares (VEMP) son electromiogramas (EMG) de latencia corta, evocados por estímulos acústicos de alto
nivel y registrados con electrodos de superficie sobre el músculo esternocleidomastoideo (SCM) tónicamente contraído, y se presume que su origen es en el sáculo. El presente experimento examina los efectos del nivel de un click y de un burst tonal, así como
de la frecuencia del estímulo, sobre la latencia, la amplitud y el umbral de los VEMP, en sujetos con sensibilidad auditiva normal y sin historia de enfermedad vestibular. Los VEMP fueron registrados en todos los sujetos utilizando un click a 100 dB nHL. La mayor parte de los sujetos
tuvieron VEMP presentes a 500, 750 y 1000 Hz, y unos pocos sujetos tuvieron VEMP a 2000 Hz. La amplitud de respuesta del VEMP se incrementó con los niveles de los clicks y los bursts tonales, mientras que la latencia de los VEMP no se vio influenciada por el nivel del estímulo.
Los VEMP más grandes evocados por burst tonales, y los umbrales más bajos se obtuvieron a 500 y 750 Hz. La latencia de los VEMP fue independiente de la frecuencia del estímulo cuando la duración del burst tonal se mantuvo constante.
Unilateral Hearing Loss in Children with Shunt-Treated Hydrocephalus
Authors: Spirakis Susan E. , Hurley Raymond M.
Published: April 2008

This study investigated the characteristics of hearing loss in children with ventriculoperitoneal (VP) shunted hydrocephalus. Twelve hydrocephalic children with patent VP shunts participated. The etiology of the hydrocephalus was either intraventricular hemorrhage or spina bifida. Audiometric
examination included pure-tone air conduction thresholds, tympanometry, contralateral and ipsilateral acoustic reflex thresholds (ARTs), and distortion product otoacoustic emissions (DPOAEs). A unilateral, high-frequency, cochlear hearing loss was found in the ear ipsilateral to the shunt
placement in 10 (83%) of the 12 shunt-treated hydrocephalic children. No hearing loss was observed in the ear contralateral to shunt placement. Based on the pure-tone audiometric findings, coupled with the decrease in DPOAE amplitude in the shunt ear, the hearing loss appears to be cochlear
in nature. We suggest that cochlear hydrodynamics are disrupted as the result of reduced perilymph pressure, a consequence of cerebrospinal fluid (CSF) reduction due to the combined effects of a patent shunt and a patent cochlear aqueduct. In addition, a concomitant brain stem involvement
is evidenced in the ART pattern, possibly produced by the patent shunt draining the CSF from the subdural space, resulting in cranial base hypoplasia. Este estudio investigó las características de la pérdida auditiva en niños con hidrocéfalo y derivación
ventrículo-peritoneal (VP). Doce niños hidrocefálicos con derivaciones permeables (VP) participaron. La etiología del hidrocéfalo fue una hemorragia intraventricular o una espina bífida. Los exámenes audiométricos incluyeron umbrales
tonales puros de conducción aérea, timpanometría, umbrales de reflejo acústico ipsilateral y contralateral (ART) y emisiones otoacústicas por productos de distorsión (DPOAE). Se encontró una hipoacusia unilateral, en las altas frecuencias, en
el oído ipsilateral a la colocación de la derivación en 10 (83%) de los 12 niños hidrocefálico tratados con la derivación. Ninguna pérdida auditiva se observó en el oído contralateral al lado de colocación de la derivación.
Basados en los hallazgos audiométricos tonales puros, sumado a la disminución en la amplitud de las DPOAE en el oído de la derivación, la hipoacusia parece ser coclear en su origen. Sugerimos que la hidrodinámica coclear está alterada como resultado
de la presión endolinfática disminuida, como consecuencia de la reducción en el líquido cefalorraquídeo (CSF), debido a los efectos combinados de la derivación patente y del acueducto coclear patente. Además, un compromiso concomitante del tallo
cerebral es evidenciado en el patrón de los reflejos (ART), posiblemente producido por el drenaje de CSF que produce la derivación patente a partir del espacio subdural, resultando en una hipoplasia de la base del cráneo.
The Effects of High-Frequency Hearing Loss on Low-Frequency Components of the Click-Evoked Otoacoustic Emission
Authors: Murnane Owen D. , Kelly John K.
Published: April 2008

Click-evoked otoacoustic emission (CEOAE) input/output (I/O) functions were measured in ears with normal hearing and in ears with sensorineural hearing loss above 2000 Hz. The low- to midfrequency CEOAEs obtained from the ears with high-frequency hearing loss were significantly reduced
in level compared to the CEOAEs obtained from the ears with normal hearing even though there were no significant group differences in the 250–2000 Hz pure-tone thresholds. The findings are discussed within the context of two hypotheses that explain the low- to midfrequency reduction
in transient-evoked otoacoustic emission (TEOAE) magnitude: (1) subclinical damage to the more apical regions of the cochlea not detected by behavioral audiometry, or (2) trauma to the basal region of the cochlea that affects the generation of low-frequency emissions. It is proposed that localized
damage at basal cochlear sites affects the generation of low- to midfrequency CEOAE energy. Se midieron las funciones de input/output (I/O) para emisiones otoacústicas evocadas por clicks (CEOAE) en oídos con audición normal y en oídos con hipoacusias sensorineurales
por encima de los 2000 Hz. Las CEOAE de baja a media frecuencia obtenidas a partir de los oídos con hipoacusia de alta frecuencia fueron significativamente reducidas en su nivel, comparadas con las CEOAE obtenidas de los oídos con audición normal, aunque no existieron
diferencias significativas de grupo en los umbrales tonales de 250-2000 Hz. Los hallazgos se discuten dentro del contexto de dos hipótesis que explican la reducción en las frecuencias bajas a medias, en emisiones en la magnitud de las otoacústicas evocadas por transitorios
(TEOAE): (1) daño sub-clínico a las regiones más apicales de la cóclea, no detectadas por la audiometría conductual, o (2) trauma a la región basal de la cóclea que afecta la generación de emisiones de baja frecuencia. Se propone que
el daño localizado a los sitios basales de la cóclea afecta la generación de la energía de las CEOAE de baja a media frecuencia.
The Effect of Mild Hearing Impairment on Auditory Processing Tests
Authors: Neijenhuis Karin , Tschur Hans , Snik Ad
Published: April 2008

The application of auditory processing tests to patients with sensorineural hearing loss is controversial. Several studies have shown that it is difficult to separate peripheral from central hearing processes. In the present study, a Dutch auditory processing test battery was administered
to 24 subjects with mild, relatively flat, symmetrical sensorineural hearing loss. Tests were administered twice; the second time, the presentation level in four out of the six tests was adjusted according to the speech reception threshold. The scores of the hearing-impaired subjects were
significantly poorer than those of the subjects with normal hearing on five out of the six tests, even with the adjusted presentation level. Significant correlations were found between test scores and PTA (pure-tone average); scores on words-in-noise, filtered-speech and binaural-fusion tests
were additionally corrected according to PTA. In contrast to previous studies in the literature, the present dichotic-digit and pattern-recognition tests were greatly influenced by mild hearing loss. Therefore, this auditory processing test battery cannot readily be used to diagnose central
auditory processing disorders in patients with flat sensorineural hearing loss. At least, both adjustment of presentation level and additional correction are needed. La administración de pruebas de procesamiento auditivo a pacientes con trastornos auditivos sensorineurales es controversial.
Varios estudios han mostrado que es difícil separar los procesos auditivos periféricos de los centrales. En el presente estudio, se administró una batería holandesa de pruebas de procesamiento auditivo a 24 sujetos, portadores de una hipoacusia sensorineural leve,
simétrica y relativamente plana. Las pruebas se aplicaron dos veces; en la segunda vez, el nivel de presentación en cuatro de las seis pruebas se ajustó de acuerdo al umbral de recepción del lenguaje. Los puntajes de los sujetos hipoacúsicos fueron significativamente
peores que aquellos de los sujetos con audición normal en cinco de las seis pruebas, aún con los niveles ajustados de presentación. Se encontraron correlaciones significativas entre los puntajes de las pruebas y el PTA (promedio tonal puro). Los puntajes con palabras en
ruido, con lenguaje filtrado y con pruebas de fusión binaural fueron también corregidos de acuerdo al PTA. En contraste con estudios previos en la literatura, las hipoacusias leves influyeron importantemente en las presentes pruebas de dígitos dicóticos y de reconocimiento
de patrones. Por lo tanto, esta batería de pruebas de procesamiento auditivo no puede ser utilizada para diagnosticar trastornos centrales de procesamiento auditivo en pacientes con trastornos auditivos sensorineurales de perfil plano. Al menos, se requieren ajustes en el nivel de presentación
y correcciones adicionales.
Masking Redux I: An Optimized Masking Method
Authors: Turner Robert G.
Published: April 2008

This is the first in a series of two papers on masking. The objective of these papers is to develop a masking protocol that provides valid measures of threshold and is, in general, faster than the plateau method. In this paper, a masking method is developed that can replace the traditional
plateau method in most masking situations. This new method is optimized to require fewer masking levels than the plateau method. As a result, it can be significantly faster than the plateau method. There are some masking situations in which this optimized method cannot be used. This limitation
will be evaluated in the second paper and an alternate masking strategy provided for use when the optimized method is not appropriate. Este es el primero de una serie de dos trabajos relacionados con el enmascaramiento. El objetivo de estos trabajos es desarrollar un protocolo de enmascaramiento
que proporcione mediciones válidas del umbral y que sea, en general, más rápido que el método del plateau. En este trabajo, se desarrolla un método de enmascaramiento que reemplaza el tradicional método del plateau, en la mayoría de las situaciones
que requieren enmascaramiento. El nuevo método está optimizado para requerir menos niveles de enmascaramiento que el método del plateau. Como resultado, puede ser significativamente más rápido. Existen algunas situaciones donde este método optimizado
no puede ser usado. Esta limitación será evaluada en el segundo trabajo, donde se aportará una estrategia alternativa de enmascaramiento para usar cuando el método optimizado no sea apropiado.
Reception Thresholds for Sentences in Bilingual (Spanish/English) and Monolingual (English) Listeners
Authors: von Hapsburg Deborah , Champlin Craig A. , Shetty Suparna R.
Published: April 2008

Recent evidence on the perceptual performance of bilingual listeners suggests that a nonaudibility-based cost exists in processing a second language. That is, when compared to monolingual English speakers and early bilinguals, listeners who acquired English as a second language after
puberty show reduced performance when listening to the second language in background noise, despite normal auditory thresholds. However, past studies have not controlled for the homogeneity of the bilingual participants used in auditory research; therefore, it is unknown whether the deficit
observed in bilingual function is due to a lack of control for language-related variables. The ability of a homogeneous group of Spanish-English bilinguals and English monolingual listeners to perceive sentences in quiet and in noise at threshold levels was evaluated using the Hearing in Noise
Test (HINT). Both groups performed similarly in quiet conditions. In the noise conditions, the bilingual group's performance was significantly poorer than the monolingual group's performance. However, both groups showed a binaural advantage of 7–8 dB when the signal and noise were separated
by 90 degrees. La evidencia reciente sobre el rendimiento perceptivo de sujetos bilingües sugiere que, en relación con el procesamiento de una segunda lengua, existe un costo no relacionado con la audibilidad. Esto es, cuando se les compara con hablantes monolingües del inglés
y con bilingües de adquisición temprana, los sujetos que adquirieron el inglés como segunda lengua después de la pubertad, muestran una ejecución reducida cuando escuchan esta segunda lengua en medio de ruido de fondo incrementado, a pesar de tener umbrales
auditivos normales. Sin embargo, los estudios anteriores no controlaron la homogeneidad de los participantes bilingües utilizados en investigación auditiva; por lo tanto, no se sabe si el déficit observado en la función bilingüe es debido a la falta de control
de variables relacionadas con el lenguaje. Se evaluó la capacidad de un grupo homogéneo de sujetos bilingües en españolinglés y de sujetos monolingües en inglés para captar frases en silencio y en ruido, a niveles de umbral, con la prueba de Audición
en Ruido (HINT). Ambos grupos rindieron en forma similar en condiciones de silencio. Pero en condiciones de ruido, el rendimiento del grupo bilingüe fue significativamente peor que el rendimiento del grupo monolingüe. Sin embargo, ambos grupos mostraron una ventaja binaural de 7-8
dB cuando la señal y el ruido fueron separados por 90 grados.