Biomedical subjects
Publications and source records attributed to C Angelborg.
Cochlear and cerebral blood flows were measured in albino rabbits by the microsphere method before and 15 min after intravenous administration of glycerol. Both cochlear and cerebral blood flow were significantly increased. The increase in cochlear blood circulation is interpreted as a contributory factor in producing the improvements in hearing threshold seen in the positive glycerol test in Ménière's disease.
Hearing was studied in nineteen patients with Meniere's disease before and after administration of three different hyperosmolar solutions-glycerol, ethanol, and Mannitol. Ethanol and Mannitol were found to be much less effective than glycerol in producing hearing gain. Alternative mechanisms underlying the observed differences are discussed.
The cochlear and cerebral blood flow was studied in rabbits with the microsphere method before and 15 min after i.v. administration of ethanol. In a series of control experiments only saline was injected. No alteration was measured in the cochlear and cerebral blood flow after the administration of saline, whereas both cochlear and cerebral blood flow showed an increase after ethanol administration. The results are discussed in relation to changes in serum osmolality and hearing in patients with Menière's disease.
The cochlear blood flow was measured with the microsphere methods, before and during CO2-inhalation, in anesthetized rabbits. Different gas mixtures and exposure times were used. The greatest increase of cochlear blood flow was measured after 5 min inhalation of 7% CO2 in air (115%) and the least increase (44%) in animals breathing 7% CO2 in oxygen. The difference is explained as due to a vasoconstriction caused by a high oxygen tension counteracting the vasodilating effect of CO2.
The cochlear blood flow was measured with the microsphere method before, during and after CO2 inhalation in anesthetized rabbits. Different gas mixtures and exposure times were used. The greatest increase of cochlear blood flow was measured after 5 min inhalation of 7% CO2 in air (115%) and the least increase (44%) in animals breathing 7% CO2 in oxygen. The difference is explained as due to a vasoconstriction caused by a high oxygen tension counteracting the vasodilating effect of CO2. The treatment with CO2 of supposed vascular diseases in the cochlea is discussed and the negative effects due to respiratory acidosis are emphasized.
The effect of noise after unilateral transection of the cervical sympathetic trunk on cochlear blood flow was studied in anesthetized cats. The sound pressure level was 100 dB and the exposure time 6 min. Neither noise nor sympathectomy were found to affect the blood flow.
The effect of noise and unilateral transection of the cervical sympathetic trunk on cochlear blood flow was studied in anesthetized cats. The sound pressure level was 100 dB and the exposure time 6 min. Neither noise nor sympathectomy were found to affect the blood flow.
The cochlear blood flow was studied with the microsphere method in guinea pigs, rats and cats. Results from experiments using different sizes of microspheres were compared and the effect of middle ear infection or perforation of the otic capsule on the cochlear microcirculation was investigated. Neither the opening of the cochlear bony wall nor the middle ear infection influenced the blood flow in the cochlea. 9- and 15-micrometer spheres were given simultaneously and the results were equivalent, indicating no more shunting of the smaller ones than of the bigger ones. Thus, the smaller spheres are to be preferred, since the smaller ones can be used in a larger number without negative effects on the general circulation. In cats, the cochlear blood circulation was determined before and during cervical sympathetic stimulation. Sympathetic stimulation caused a reduction of 25% of the cochlear blood flow.
A case of esthesioneuroblastoma was examined by histological, histochemical and electron microscopic techniques. The tumour cells showed an argyrophil reaction with the Grimelius technique and contained cytoplasmic secretory granules, but in contrast to previous reports were devoid of histochemically demonstrable biogenic amines. For routine diagnosis the argyrophil technique may be useful in differentiating this type of tumour from epidermoid carcinoma.
Transient hearing improvement was recorded in around 60% of patients with Menière's disease 2 hours after the ingestion of 20 g of urea perorally. Urea slightly increased the serum osmolality, which is thought to cause a transient reduction of the endolymphatic hydrops. Urea has no inconvenient side effects and is recommended primarily as a test substance for the verification of endolymphatic hydrops, in conformity with glycerol.
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Using the microsphere method combined with light microscopic observation of serially sectioned plastic-embedded cochleas, the distribution of microspheres trapped within the cochlea can be observed and the regional blood flow can be determined. In the guinea pig, the blood flow is greatest in the lateral wall, high in the modiolus, and low under the organ of Corti.
Glycerol has been injected intravenously in guinea pig and its effects on the pressure in the cochlear fluids have been studied. Simultaneously, arterial and cerebro-spinal pressures have been recorded. Glycerol lowered the intracochlear as well as cerebro-spinal and blood pressures, the latter only temporarily. Different possible mechanisms for the glycerol effect on the intracochlear pressure and its transient effect on hearing in Menière's disease are discussed.
Cochlear blood flow in the guinea pig was investigated using Tracer Sephadex 15 microspheres labelled with radioactive nuclides. A reference organ technique was used for quantitative measurements of cardiac output and the blood flow in the cochlear soft tissue, CNS and kidney. In some experiments the blood flow was measured at two occasions, either with 57Coor with 58Co-labelled microspheres. The results, including the size of cochlear blood flow are presented and discussed.