| 1. |
- Arup, Ulf, et al.
(author)
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Placidiopsis custnani – a new pyrenocarpous species to Sweden
- 2014
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In: Graphis Scripta. - 0901-7593. ; 26:1-2, s. 42-45
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Journal article (peer-reviewed)abstract
- Placidiopsis custnani (A. Massal.) Körb., last recorded from the Nordic countries almost 160 years ago, is reported from the island of Gotland as new to Sweden. Its taxonomy and ecology are described from the new locality, and a key is provided for the former members of the genus Catapyrenium growing on soil, mosses or bark in the Nordic countries.
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| 2. |
- Arup, Ulf, et al.
(author)
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Placidium umbrinum – a pyrenocarpous species new to northern Europe.
- 2011
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In: Graphis Scripta. - 0901-7593. ; 23:2, s. 42-46
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Journal article (peer-reviewed)abstract
- Placodium umbrinum Breuss is reported as new to northern Europe from the island of Gotland, Sweden. The species is described and depicted, and its ecology at the locality on Gotland is given. A key is given for former members of the genus Catapyrenium growing on soil, mosses or bark in the Nordic countries.
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| 3. |
- Pettersson, Åke, et al.
(author)
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Skolsvenskan duger inte
- 2007
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In: Sydsvenskan. - 1652-814X. ; :261
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Journal article (pop. science, debate, etc.)
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| 4. |
- Stenqvist, Monika, et al.
(author)
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Cochlear changes after lateral and posterior semicircular canal destruction in healthy and previously toxin exposed rats : An electrophysiological and morphological investigation
- 1997
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In: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 117:5, s. 681-688
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Journal article (peer-reviewed)abstract
- One group of Sprague-Dawley rats (group A, n = 6) was treated by instilling Pseudomonas aeruginosa exotoxin A (PaExoA), and another (group B, n = 6) treated similarly with Haemophilus influenzae type b endotoxin (HiBEndo). In group A a 20 dB hearing loss was observed, predominantly in the high-frequency region, which was reversible within 1 month. In group B no significant hearing impairment was noted. Between 1 and 6 months later, the lateral and posterior semicircular canals (SCCs) were ablated unilaterally. Control rats (group C, n = 8) were subjected to ablation only. All rats were cochleotomized contralaterally prior to labyrinthine surgery. Frequency-specific evoked potential testing at 2-31.5 kHz tone bursts was performed before and directly after surgery, 6, 24 and 48 hours and 1, 4 and 16 weeks postoperatively. After surgery in 18 rats, thresholds rose immediately, predominantly at 2, 4 and 6 kHz, followed by varying degrees of recovery. Greatest immediate postoperative hearing loss was observed in group A; no rat recovered completely and two rats showed severe permanent threshold elevation. All group B rats recovered completely, except one showing moderate threshold impairment. No permanent hearing loss was observed in group C. This study shows that destruction of SCCs in rats does not necessarily cause permanent hearing loss, even if the fluid spaces are not sealed off. However, previous exposure of the middle ear to PaExoA (but not HiBEndo) renders the cochlea more vulnerable and can result in persistent hearing loss.
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| 5. |
- Stenqvist, Monika, et al.
(author)
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Effect of Pseudomonas aeruginosa exotoxin A on inner ear function
- 1997
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In: Acta Oto-Laryngologica. - 0001-6489 .- 1651-2251. ; 117:1, s. 73-79
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Journal article (peer-reviewed)abstract
- Electrophysiological changes were studied in the albino rat following instillation of Pseudomonas aeruginosa exotoxin A into the middle ear cavity through the tympanic membrane. Hearing threshold was measured by a burst-elicited, frequency-specific auditory brainstem response (ABR) technique prior to exposure, then 24 and 48 h, 5 days, 2 and 4 weeks after the toxin instillation. A single dose (1 microgram/20 microliters) of Pseudomonas aeruginosa exotoxin A raised the ABR threshold over the whole frequency range, by 5-25 dB, particularly in the high tones. All threshold shifts were of combined conductive and cochlear type, reversible, with deterioration starting at 24-48 h and recovery at 2-4 weeks. Effusion of serous fluid occurred at 24 or 48 h, resulting in conductive hearing loss. Latency/intensity curves revealed a cochlear component in addition to conductive hearing loss. Morphological examination by SEM showed slight and inconsistent derangement of OHCs. It is concluded that Pseudomonas aeruginosa exotoxin A causes middle ear inflammation, facilitating penetration to the inner ear and that this toxin also reversibly affects cochlear function.
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| 6. |
- Stenqvist, Monika, et al.
(author)
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Electrophysiological effects of multiple instillation of Haemophilus Influenzae Type b endotoxin on the inner ear
- 1997
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In: Acta Oto-Laryngologica. - 0001-6489 .- 1651-2251. ; 117:3, s. 352-7
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Journal article (peer-reviewed)abstract
- An analysis of auditory brainstem response (ABR) thresholds and ABR-based frequency tuning curves was performed in 15 Sprague-Dawley rats exposed to Haemophilus influenzae type b endotoxin; 5 microg/50 microl toxin was instilled every second day, altogether five times, into the middle ear cavity through a small perforation in the tympanic membrane. ABR was measured 48 h after the second application and 24 h, 48 h, 5 days and 10 days after the fifth instillation. Five applications of toxin had no statistical effect on ABR thresholds and no changes in TC configuration were observed. It is concluded that Haemophilus influenzae type b endotoxin, instilled repeatedly through the tympanic membrane into the middle ear, does not affect cochlear electrophysiology.
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| 7. |
- Kakoi, Hiroyuki, et al.
(author)
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Auditory epithelial migration : I. Macroscopic evidence of migration and pathways in the rat
- 1996
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In: Acta Oto-Laryngologica. - 0001-6489 .- 1651-2251. ; 116:3, s. 435-8
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Journal article (peer-reviewed)abstract
- Auditory epithelial migration (AEM) was studied in the rat for up to 42 days following the application of dye on the tympanic membrane (TM) and external auditory canal (EAC). Migratory pathways were similar to those in the human. In the pars tensa (PT), pathways were radially and centrifugally oriented from the handle of the malleus (HM) toward the annulus. However, the pathway along the HM from the umbo to the pars flaccida (PF), as reported in the human, was not observed in the rat; instead, a shallow downward pathway along the HM. In the PF, the radial spread of dye-markings from the proximal part of the HM to the upper wall of the EAC, as found in the human, was also observed in the rat. We conclude that the TM and EAC of the rat constitute an appropriate experimental model with which to study the human type of AEM.
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| 8. |
- Kakoi, Hiroyuki, et al.
(author)
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Morphological changes in rat submandibular gland mucous cells during fixation with 10% formalin
- 1996
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In: European Archives of Oto-Rhino-Laryngology. - 0937-4477 .- 1434-4726. ; 253:4-5, s. 214-21
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Journal article (peer-reviewed)abstract
- The features of mucous cells in 10% formalin (FA)-fixed submandibular glands differ markedly from those fixed in glutaraldehyde (GA). We therefore studied morphological changes in mucous cells during 10% FA fixation. Mucous cells were fixed in either 10% FA, neutral sodium-phosphate-buffered (Na-PBed) 10% FA, ice-cold 10% FA or an ice-cold fixative mixture of 2.0% paraformaldehyde (PA) and 0.5% GA. Two different methods were used: immersion fixation and venous perfusion fixation. The 10% FA-fixed tissues had elliptical or flattened nuclei, a clear cytoplasm and no secretory granules. Tissues fixed with the fixative mixture displayed almost round nuclei, a broad endoplasmic reticulum and abundant secretory granules in the cytoplasm. Tissues immersion-fixed with neutral Na-PBed 10% FA or perfusion-fixed with ice-cold 10% FA had almost the same light microscopic appearance as that of the mixture-fixed tissues. To elucidate the process of morphological changes during 10% FA fixation at room temperature, samples immersed in 10% FA for varying periods of time were postfixed immediately in the fixative mixture and exposed to microwave irradiation. This method produced a variety of findings, even within the same section. There was a significant difference in the findings seen in the center of the section and at the periphery. The initial changes caused by 10% FA were rupture of the secretory granules located in the perinuclear region and destruction of the perinuclear organelles such as Golgi apparatus, mitochondria and endoplasmic reticulum. Absorption of the endoplasmic reticulum progressed so that the perinuclear region became translucent. To obtain a better structure in mucous cells from the fixed submandibular gland tissues, an appropriate fixative such as GA should be used and the fixative should infiltrate into the tissues as quickly as possible.
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| 9. |
- Anniko, Matti, et al.
(author)
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Alpha-Bungarotoxin Inhibits Outer Hair Cell Motility in situ
- 1995
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In: Journal for Oto-Rhino-Laryngology. - : S. Karger AG. - 0301-1569 .- 1423-0275. ; 57:2, s. 105-109
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Journal article (peer-reviewed)abstract
- The effect of two substances (alpha-bungarotoxin, alpha-BGTX, a small protein, and the local anesthetic bupivacaine hydrochloride) with an assumed effect on outer hair cell (OHC) motility were analyzed after exposing the cochlea via the round window membrane. Electrophysiological measurements were performed with a very narrow frequency-specific gating (+/- 100 Hz) technique to determine auditory brainstem response (ABR) thresholds, including ABR-based frequency tuning curves. Exposure to alpha-BGTX gave a minor improvement in thresholds, interpreted as a facilitation of OHCs, i.e. releasing their efferent inhibitory control, whereas exposure to bupivacaine hydrochloride impaired ABR thresholds, possibly due to immobilization of OHC motility via the lateral cell membrane. Our results are consistent with the hypothesis that efferent influence on the cochlea may be linked with a modulation of the mechanical function of OHCs. We can now postulate that there is in vivo evidence that acetylcholine exerts its effect at the OHCs via an alpha-BGTX alpha-BGTX binding acetylcholine receptor.
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| 10. |
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