Biomedical subjects

A Ivarsson

Publications and source records attributed to A Ivarsson.

98 records · Page 6Linked to original sources

PubMedDate not supplied

Patency of the maxillary sinus ostium in healthy individuals.

In a group of 20 healthy subjects the patency of the maxillary ostium has been evaluated in 35 maxillary sinuses with three different techniques: simultaneous pressure recording in the sinus and the ipsi- and contralateral nasal cavity; simultaneous recording of differential pressure between the sinus and the ipsilateral nasal cavity and air-flow through the ostium during nasal breathing; recording of the pressure rise in the sinus with an artificial air-flow of 1 litre per minute applied to the sinus. The tests were carried out in sitting and recumbent positions. In 5 persons (10 sinuses) a retest was performed after 2 months. These subjects were also tested with an inflatable neck cuff in order to obtain an increased venous pressure. Rhinomanometry at rest and after physical effort was also performed. The pressure relationship between the maxillary sinus and the ipsilateral nasal cavity was 1:1 in both the sitting and the recumbent position, but less than 1 when the contralateral nasal cavity was measured. Pressure recording alone gives no quantitative information about the patency of the ostium. Determination of the ostial resistance during nasal breathing could be performed in 13 sinuses, but in the remaining 22 the ostia were too wide to give a measurable resistance. The equivalent ostial diameter during inspiration could be estimated in 12 of the sinuses from a diagram constructed from known ostial diameters in model experiments. With an artificial air-flow applied into the sinus, the equivalent ostial diameters could be estimated from the diagram in all cases. No statistical difference was found in comparable cases between the mean equivalent ostial diameters estimated with the two methods. The equivalent ostial diameters showed a statistically significant reduction in the recumbent position and after application of the neck cuff. A statistically significant relationship was also found between the airway resistance of the nasal cavity and the equivalent diameter of the ostium in sitting and recumbent positions. Such a relationship could not be found between the equivalent ostial diameters measured at rest and the nasal resistance recorded after physical effort.

Adult↗

PubMedDate not supplied

Studies on the maxillary ostial function in cases with maxillary pain, intrasinusal cysts and chronic sinusitis.

The maxillary ostial function, measured as pressure transmission capacity, ostial airway resistance, equivalent ostial diameter during nasal breathing and with a constant artificial air-flow of 16.7 cm3 X S-1 into the sinus, was compared in three groups of patients. One group consisted of 7 sinuses in 6 patients with maxillary pain but without any signs of sinusitis; a second group of 6 sinuses in 6 patients with intramaxillary cysts; and a third group of 6 sinuses in 5 patients with chronic maxillary sinusitis. No impairment of the ostial function was found in groups one and two. In the third group an increased airway resistance of the ostia and small equivalent ostial diameters were found in both sitting and recumbent positions. With the pressure recording technique, the ostium can be judged as patent, non-patent, or partially obstructed, but no further grading can be done. With the pressure-flow technique the ostial function can be evaluated as ostial resistance or equivalent ostial diameters under 'physiological conditions' when the ostium is patent. With a constant artificial air-flow into the sinus the equivalent ostial diameter can be estimated even in non-patent ostia but the equivalent ostial diameters obtained do not always reflect the true functional state of the ostium.

Adult↗

PubMedDate not supplied

The effect of pressure change rate on the eustachian tube function in pressure chamber tests.

The capacity of the Eustachian tube to equilibrate pressure differences across the eardrum was tested repeatedly at different rates of pressure change with the aid of a quantitative impedance method in a pressure chamber. Three recordings of the active and passive pressure equilibration functions were made during chamber pressure changes of 0.3, 0.7 and 1.5 kPa-1s in 53 ears in 28 otologically healthy subjects. The middle ear pressures at which the active and passive equilibrations were achieved increased with increasing rates. The test-retest reliability was not rate dependent as regards the passive pressure equilibration functions, but tended to deteriorate with increasing rates for the active equilibration functions. Advantages and disadvantages of the different rates in such tests are discussed.

Adult↗

PubMedDate not supplied

Effects of phenylpropanolamine on ostial and nasal patency in patients treated for chronic maxillary sinusitis.

Ostial and nasal patency were measured in different body positions and after phenylpropanolamine (Ppa) treatment in 12 patients earlier treated for chronic unilateral maxillary sinusitis of varying severity. Six of the sinuses were of normal appearance on sinoscopy. Phenylpropanolamine in a single dose of 100 mg was found to increase the equivalent ostial diameter significantly in the sitting and recumbent positions. The drug also reduced the nasal airway resistance. The Ppa effect might be of benefit in patients treated for chronic maxillary sinusitis.

Adult↗

PubMedDate not supplied

Effects of phenylpropanolamine on ostial and nasal airway resistance in healthy individuals.

Ostial airway resistance (OAR) of 11 maxillary ostia and the airway resistance of the nasal cavity (NAR) in 6 healthy persons were tested before and after administration of phenylpropanolamine (Ppa) and placebo. The effects of physical exercise were also tested. After logarithmic transformation, the resistance values showed a normal distribution. Significant effects on the ostial resistance in relation to initial values were found after Ppa medication. The effect was more pronounced in recumbency than in the sitting position. Physical exercise also gave a significant reduction of ostial resistance while placebo treatment was without effect. On comparison of the Ppa- and placebo-groups in an extended statistical analysis, more striking differences were found both for OAR and NAR. In this model study, Ppa thus showed effects in healthy individuals.

Adult↗

PubMedDate not supplied

Ostial and nasal patency in chronic maxillary sinusitis. A long-term post-treatment study.

In a long-term follow-up study (mean 3.5 years) after treatment of chronic maxillary sinusitis of either rhinogenous or dental origin, 72 sinuses in 66 patients were examined with respect to maxillo-ostial and nasal resistance. In sinusitis of rhinogenous etiology, the mean equivalent ostial diameter was pathologically narrowed (0.89 mm, in patients treated conservatively) whereas it was normal (2.51 mm) in sinusitis of dental etiology (dental treatment in combination with local sinus surgery). In the former group, all sinuses were diseased, compared with 3 out of 23 in the dental group. In order to distinguish between functional and organic ostial stenosis, the patients were also tested after physical exercise. The functional ostial diameter in healthy sinuses was significantly increased in contrast to the diseased sinuses. In one patient the narrow ostium was due to mucosal swelling only, but in the other cases was caused mainly by an organic stenosis. In sinusitis of rhinogenous etiology, a pathologically increased nasal resistance was found in 14.3%, while the corresponding figure in the dental group was 4.3%. Improved sinusal and nasal ventilation, achieved either pharmacologically or, preferably by surgical intervention, seems necessary for successful treatment of chronic maxillary sinusitis.

Adult↗

PubMedDate not supplied

Comparison between hearing threshold measurements made with and without the aid of an ear speculum.

The hearing threshold levels of a small group of shipyard workers having differing degrees of hearing impairment were measured five times using the following audiometric techniques: fixed-tone Békésy audiometry with MX 41/AR cushions, fixed-tone Békésy audiometry with an ear speculum, and sweep-frequency Békésy audiometry with an ear speculum. From these data the mean standard deviations of the hearing threshold levels for the frequencies 0.5, 1, 2, 3, 4, 5, 6, 7 and 8 kHz were calculated, thus giving a measure of the accuracy of each method. The hearing threshold levels obtained by the three methods are compared, and the merits of data handling, expressing hearing threshold levels in pascals rather than decibels, are also discussed.

Audiometry↗

PubMedDate not supplied

Hair cell damage in the inner ear of the guinea pig due to noise in a workshop.

Guinea pigs were exposed to noise in various workshops at a shipyard. The equivalent sound level ranged from 87 to 90 dB(A) and the exposure time was 30 days of 8 hours. The numbers of lost outer hair cells were greater than in control animals, thus establishing a relation between the number of lost hair cells and the total noise dose. A comparison between the results obtained here and results obtained in laboratory experiments shows that although many physical sound parameters may be identical, the effect on the hair cells can be quite different. In particular, the total noise dose is not a parameter which can be directly related to hair cell loss. The most probable explanation for the difference in damage between the laboratory and workshop animals seems to be the rest periods of 16 hours between each of the 8-hour exposure periods.

Animals↗