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Mats Ulfendahl - One of the best experts on this subject based on the ideXlab platform.
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Type I hair cell degeneration in the utricular macula of the waltzing Guinea Pig.
Hearing research, 2007Co-Authors: Stig A Severinsen, Mats Ulfendahl, Merete K Raarup, Lise Wogensen, Jens R Nyengaard, Mette KirkegaardAbstract:Waltzing Guinea Pigs are an inbred Guinea Pig Strain with a congenital and progressive balance and hearing disorder. A unique rod-shaped structure is found in the type I vestibular hair cells, that traverses the cell in an axial direction, extending towards the basement membrane. The present study estimates the total number of utricular hair cells and supporting cells in waltzing Guinea Pigs and age-matched control animals using the optical fractionator method. Animals were divided into four age groups (1, 7, 49 and 343 day-old). The number of type I hair cells decreased by 20% in the 343 day-old waltzing Guinea Pigs compared to age-matched controls and younger animals. Two-photon confocal laser scanning microscopy using antibodies against fimbrin and betaIII-tubulin showed that the rods were exclusive to type I hair cells. There was no significant change in the length of the filament rods with age. Taken together, our data show that despite rod formation in the type I hair cells and deformation of hair bundles being present at birth, the type I hair cell population is not affected quantitatively until a year after birth.
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Augmented ototoxic effect of cisplatin in heterozygotes of the German waltzing Guinea Pig.
Audiology & neuro-otology, 2007Co-Authors: Åsa Skjönsberg, Violeta Bucinskaite, Göran Laurell, Mats UlfendahlAbstract:It has previously been demonstrated that the carriers of the German waltzing Guinea Pig are less susceptible to noise trauma. To explore whether this represents a general resistance to inner ear trauma, carriers of the German waltzing Guinea Pig were exposed to the ototoxic agent cisplatin. Two doses of cisplatin were injected intravenously into anesthetized carriers and weight-matched control animals. Prior to and 96 h after the injections hearing thresholds were established by recording the auditory brainstem responses at 3.5, 7, 14, and 28 kHz. The cochleae were harvested to estimate hair cell loss and to analyze total platinum content. The carriers of the German waltzing Guinea Pig Strain suffered from a more pronounced cisplatin-induced hearing loss compared to the control animals. The results suggest that mechanisms responsible for the protection against acoustic stress do not provide any protection against cisplatin in carriers of the German waltzing Guinea Pig.
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Auditory function and cochlear morphology in the German waltzing Guinea Pig.
Hearing Research, 2006Co-Authors: Zhe Jin, Åsa Skjönsberg, Paula Mannström, Leif Järlebark, Mats UlfendahlAbstract:The German waltzing Guinea Pig is a new Strain of animals with a recessively inherited inner ear defect resulting in deafness and severe vestibular dysfunction. Measurements of auditory brainstem responses (ABRs) demonstrated that the homozygotes (gw/gw) are deaf while the heterozygotes (gw/+) have normal hearing. In the gw/gw cochlea, a collapse of Reissner's membrane leads to the absence of scala media. Melanin Pigment accumulation was clearly observed in the gw/gw stria vascularis, and both the height and width of stria vascularis were significantly reduced. Ultrastructural observations further detailed the disorganization of stria vascularis in the gw/gw animals: marginal cells lacked basolateral infoldings; intermediate cells (melanocytes) were scarce and degenerated; and basal cells were difficult to identify. The level of degeneration of the organ of Corti varied between individual gw/gw animals. The density of spiral ganglion neurons was significantly decreased in old (1-2 years of age) gw/gw animals. In contrast, no pathological changes were observed in the cochleae of gw/+ animals. Our data suggest that the degeneration originates in the stria vascularis (most likely in the melanocytes), and that this is the primary cause for inner ear defects in the German waltzing Guinea Pig. Here, we describe the auditory function and cochlear morphology in this spontaneously mutated Guinea Pig Strain.
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A Guinea Pig Strain with Recessive Heredity of Deafness, Producing Normal-Hearing Heterozygotes with Resistance to Noise Trauma
Audiology & neuro-otology, 2005Co-Authors: Åsa Skjönsberg, Petra Herrlin, Maoli Duan, Ann-christin Johnson, Mats UlfendahlAbstract:A new Strain of waltzing Guinea Pigs arose spontaneously in a Guinea Pig breeding facility in Germany in 1996. In addition to obvious vestibular dysfunction, the waltzing animals appear deaf already a
Åsa Skjönsberg - One of the best experts on this subject based on the ideXlab platform.
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Reduced noise susceptibility in littermate offspring from heterozygous animals of the German waltzing Guinea Pig.
Neuroreport, 2015Co-Authors: Åsa Skjönsberg, Paula MannströmAbstract:The German waltzing Guinea Pig is a spontaneously mutated Strain with severe auditory and vestibular impairment caused by a so far unknown genetic mutation. The animals are born deaf and show a circling behavior. The heterozygote animals of this Guinea Pig Strain have functionally normal hearing and balance. However, these animals have, in earlier studies, shown an increased resistance to noise compared with normal wild-type Guinea Pigs. In the present study, we explored the functional hearing with auditory brainstem response thresholds before and at different time points after noise exposure. Symptom-free littermates from heterozygote couples of the German waltzing Guinea Pigs were exclusively used for the study, which, after the hearing test, were sent back for breeding to confirm their genotype (i.e. heterozygote or normal). The aim of this paper was to ascertain that the previously shown reduced susceptibility to noise trauma in the heterozygote animals of the German waltzing Guinea Pig was also evident when littermates were used as control animals. The findings are important for further analysis of the heterozygote animals of this Strain and for future investigations of the underlying mechanisms behind the diverse susceptibility to exposures of loud sound.
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Augmented ototoxic effect of cisplatin in heterozygotes of the German waltzing Guinea Pig.
Audiology & neuro-otology, 2007Co-Authors: Åsa Skjönsberg, Violeta Bucinskaite, Göran Laurell, Mats UlfendahlAbstract:It has previously been demonstrated that the carriers of the German waltzing Guinea Pig are less susceptible to noise trauma. To explore whether this represents a general resistance to inner ear trauma, carriers of the German waltzing Guinea Pig were exposed to the ototoxic agent cisplatin. Two doses of cisplatin were injected intravenously into anesthetized carriers and weight-matched control animals. Prior to and 96 h after the injections hearing thresholds were established by recording the auditory brainstem responses at 3.5, 7, 14, and 28 kHz. The cochleae were harvested to estimate hair cell loss and to analyze total platinum content. The carriers of the German waltzing Guinea Pig Strain suffered from a more pronounced cisplatin-induced hearing loss compared to the control animals. The results suggest that mechanisms responsible for the protection against acoustic stress do not provide any protection against cisplatin in carriers of the German waltzing Guinea Pig.
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Auditory function and cochlear morphology in the German waltzing Guinea Pig.
Hearing Research, 2006Co-Authors: Zhe Jin, Åsa Skjönsberg, Paula Mannström, Leif Järlebark, Mats UlfendahlAbstract:The German waltzing Guinea Pig is a new Strain of animals with a recessively inherited inner ear defect resulting in deafness and severe vestibular dysfunction. Measurements of auditory brainstem responses (ABRs) demonstrated that the homozygotes (gw/gw) are deaf while the heterozygotes (gw/+) have normal hearing. In the gw/gw cochlea, a collapse of Reissner's membrane leads to the absence of scala media. Melanin Pigment accumulation was clearly observed in the gw/gw stria vascularis, and both the height and width of stria vascularis were significantly reduced. Ultrastructural observations further detailed the disorganization of stria vascularis in the gw/gw animals: marginal cells lacked basolateral infoldings; intermediate cells (melanocytes) were scarce and degenerated; and basal cells were difficult to identify. The level of degeneration of the organ of Corti varied between individual gw/gw animals. The density of spiral ganglion neurons was significantly decreased in old (1-2 years of age) gw/gw animals. In contrast, no pathological changes were observed in the cochleae of gw/+ animals. Our data suggest that the degeneration originates in the stria vascularis (most likely in the melanocytes), and that this is the primary cause for inner ear defects in the German waltzing Guinea Pig. Here, we describe the auditory function and cochlear morphology in this spontaneously mutated Guinea Pig Strain.
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A Guinea Pig Strain with Recessive Heredity of Deafness, Producing Normal-Hearing Heterozygotes with Resistance to Noise Trauma
Audiology & neuro-otology, 2005Co-Authors: Åsa Skjönsberg, Petra Herrlin, Maoli Duan, Ann-christin Johnson, Mats UlfendahlAbstract:A new Strain of waltzing Guinea Pigs arose spontaneously in a Guinea Pig breeding facility in Germany in 1996. In addition to obvious vestibular dysfunction, the waltzing animals appear deaf already a
V Wicher - One of the best experts on this subject based on the ideXlab platform.
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Median infective dose of Treponema pallidum determined in a highly susceptible Guinea Pig Strain.
Infection and immunity, 1991Co-Authors: Konrad Wicher, V WicherAbstract:The median infective dose of Treponema pallidum subsp. pallidum and the production of immunity to reinfection in C4D Guinea Pigs have been determined with 10(1) to 10(6) organisms per infective dose. The mean infective dose is 10(2) organisms, and immunity--in those animals that demonstrated lesions--developed after 4.5 months postinfection.
Paula Mannström - One of the best experts on this subject based on the ideXlab platform.
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Reduced noise susceptibility in littermate offspring from heterozygous animals of the German waltzing Guinea Pig.
Neuroreport, 2015Co-Authors: Åsa Skjönsberg, Paula MannströmAbstract:The German waltzing Guinea Pig is a spontaneously mutated Strain with severe auditory and vestibular impairment caused by a so far unknown genetic mutation. The animals are born deaf and show a circling behavior. The heterozygote animals of this Guinea Pig Strain have functionally normal hearing and balance. However, these animals have, in earlier studies, shown an increased resistance to noise compared with normal wild-type Guinea Pigs. In the present study, we explored the functional hearing with auditory brainstem response thresholds before and at different time points after noise exposure. Symptom-free littermates from heterozygote couples of the German waltzing Guinea Pigs were exclusively used for the study, which, after the hearing test, were sent back for breeding to confirm their genotype (i.e. heterozygote or normal). The aim of this paper was to ascertain that the previously shown reduced susceptibility to noise trauma in the heterozygote animals of the German waltzing Guinea Pig was also evident when littermates were used as control animals. The findings are important for further analysis of the heterozygote animals of this Strain and for future investigations of the underlying mechanisms behind the diverse susceptibility to exposures of loud sound.
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Auditory function and cochlear morphology in the German waltzing Guinea Pig.
Hearing Research, 2006Co-Authors: Zhe Jin, Åsa Skjönsberg, Paula Mannström, Leif Järlebark, Mats UlfendahlAbstract:The German waltzing Guinea Pig is a new Strain of animals with a recessively inherited inner ear defect resulting in deafness and severe vestibular dysfunction. Measurements of auditory brainstem responses (ABRs) demonstrated that the homozygotes (gw/gw) are deaf while the heterozygotes (gw/+) have normal hearing. In the gw/gw cochlea, a collapse of Reissner's membrane leads to the absence of scala media. Melanin Pigment accumulation was clearly observed in the gw/gw stria vascularis, and both the height and width of stria vascularis were significantly reduced. Ultrastructural observations further detailed the disorganization of stria vascularis in the gw/gw animals: marginal cells lacked basolateral infoldings; intermediate cells (melanocytes) were scarce and degenerated; and basal cells were difficult to identify. The level of degeneration of the organ of Corti varied between individual gw/gw animals. The density of spiral ganglion neurons was significantly decreased in old (1-2 years of age) gw/gw animals. In contrast, no pathological changes were observed in the cochleae of gw/+ animals. Our data suggest that the degeneration originates in the stria vascularis (most likely in the melanocytes), and that this is the primary cause for inner ear defects in the German waltzing Guinea Pig. Here, we describe the auditory function and cochlear morphology in this spontaneously mutated Guinea Pig Strain.
Konrad Wicher - One of the best experts on this subject based on the ideXlab platform.
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Median infective dose of Treponema pallidum determined in a highly susceptible Guinea Pig Strain.
Infection and immunity, 1991Co-Authors: Konrad Wicher, V WicherAbstract:The median infective dose of Treponema pallidum subsp. pallidum and the production of immunity to reinfection in C4D Guinea Pigs have been determined with 10(1) to 10(6) organisms per infective dose. The mean infective dose is 10(2) organisms, and immunity--in those animals that demonstrated lesions--developed after 4.5 months postinfection.