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Helicobacter pylori, one of the most common bacterial pathogens of humans, colonizes the gastric mucosa, where it appears to persist throughout the host's life unless the patient is treated. Colonization induces chronic gastric inflammation which can progress to a variety of diseases, ranging in severity from superficial gastritis and peptic ulcer to(More)
The endocochlear potential (EP) was reversibly decreased in adult gerbils by the intraperitoneal injection of furosemide, while cochlear functioning was monitored by measurement of distortion production otoacoustic emissions (DPE) at a range of stimulus intensities. Stimulus frequencies for DPEs were f1 = 6.8 and f2 = 8 kHz (f2/f1 = 1.18). Emissions(More)
The US Acid Rain Program (Title IV of the 1990 Clean Air Act Amendments) has achieved substantial reductions in emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) from power plants in the United States. We compare new estimates of the benefits and costs of Title IV to those made in 1990. Important changes in our understanding of and ability to(More)
The auditory function of four wild-caught echidnas was measured using distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs). Emission audiograms were constructed by finding the stimulus levels required to produce a criterion emission amplitude at a given stimulus frequency. For an emission amplitude of -10 dB SPL, the(More)
Auditory characteristics of metabolic or strial presbycusis were investigated using an animal model in which young adult Mongolian gerbils ( Meriones unguiculates) were implanted with an osmotic pump supplying furosemide continuously to the round window. This model causes chronic lowering of the endocochlear potential (EP) and results in auditory responses(More)
The inositol phosphatases phosphatase and tensin homologue (PTEN) and Src homology 2 domain-containing inositol phosphatase (SHIP) negatively regulate phosphatidylinositol-3-kinase (PI3K)-mediated growth, survival, and proliferation of hematopoietic cells. Although deletion of PTEN in mouse T cells results in lethal T cell lymphomas, we find that animals(More)
Exposure of naïve B cells to the cytokine interleukin-4 (IL-4) and/or antigen leads to a state of "priming," in which subsequent aggregation of major histocompatibility complex class II molecules induces the mobilization of calcium ions and cell proliferation. However, it is not clear how critical this priming is for immune responses or how it is normally(More)
Cochlear function was monitored in adult gerbils using distortion product otoacoustic emissions (DPOAE) during intraperitoneal injection of furosemide. All stimulus parameters were varied independently over a wide range, the stimulus frequencies f1 and f2 from 1 to 16 kHz, and the stimulus levels L1 and L2 from 20 to 80 dB SPL. The observed emissions at(More)
OBJECTIVE The purpose of this study was to further investigate the possibility of developing noninvasive methods of differential diagnosis of hearing disorders through the study of experimental animals with induced lesions. In particular, it was desired to compare distortion product otoacoustic emission (DPOAE) responses and auditory brain stem response(More)
The development of the cochlear amplifier was examined in gerbils aged 14 days after birth (dab) to adult, for stimulus frequencies from 1 to 48 kHz. Distortion product otoacoustic emissions (DPOAEs) were employed to determine the characteristics of active emissions associated with cochlear amplifier operation. DPOAEs were also used to determine the(More)