Claes Erwall

Indoor air pollutants in schools: nasal patency and biomarkers in nasal lavage

Background: There is growing concern about the respiratory health aspects of the indoor air quality in schools.

Nasal Congestion in Relation to Low Air Exchange Rate in Schools: Evaluation by Acoustic Rhinometry

Upper airway symptoms are common, but there is little information available on clinical findings in relation to indoor air pollution. This pilot study was conducted to test whether increased levels of indoor air pollutants in schools may correlate to a swelling of the nasal mucosa. The assumption was made that the degree of swelling could be related to the degree of decongestive effect of xylometazoline, and measured by acoustic rhinometry. The study was performed among 15 subjects in a school with low air exchange rate (0.6 air changes/h) and 12 subjects in a school with high air exchange rate (5.2 air changes/h). Hygienic measurements were performed in both schools. Acoustic rhinometry was performed for each individual under standardized forms. Cross-sectional areas and volumes of the nasal cavity were measured before and after decongestion with xylometazoline hydrochloride. Absolute values of the minimal cross-sectional area were lower in the school with poor ventilation. The decongestive effect of xylometazoline was significantly higher in the school with low air exchange, when correction for the influence of age was made. A diminished decongestive effect was seen with increasing age. The exposure measurements showed that indoor concentrations of volatile organic compounds, bacteria and moulds were higher in the school with low ventilation. In conclusion, raised levels of indoor air pollutants due to inadequate ventilation in schools may affect the upper airways and cause a swelling of the nasal mucosa, and acoustic rhinometry could be a useful objective method to measure human nasal reactions to the indoor environment.

Hyaluronan Content in Human Inner Ear Fluids

Histochemical analyses of the luminal contents of the endolymphatic sac in numerous mammalian species have indicated a presence of acid mucopolysaccharides or proteoglycans. In the present study, one of these substances, hyaluronan (hyaluronic acid; HA), in endolymphatic sac endolymph and vestibular perilymph in humans, was biochemically determined with a highly specific radioassay. A considerable variation in HA concentration was noted between the individual ES endolymph samples, with a mean value of 2.50 micrograms/g (range 0.00-10.86). In perilymph the HA concentrations were less variable and the mean concentration was 0.91 micrograms/g (range 0.56-1.51). The difference between endolymph and perilymph HA concentration was not statistically significant (p greater than 0.05). The ability of HA to interact with proteoglycans, thereby forming giant hydrophilic molecules, could be important for ES function. These molecules may create a swelling pressure which is resistant to compressive forces that under conditions of increased intracranial hydrostatic pressure otherwise could cause ES collapse and impaired function.

Origin of Sympathetic and Sensory Innervation of the Endolymphatic Sac

Lectin-conjugated horseradish peroxidase (WGA-HRP) was used as a retrograde axonal tracer to determine endolymphatic sac (ES) innervation and the nature of such a nervous supply. WGA-HRP placed into the ES of the guinea pig resulted in labelling of neurons in the ipsilateral sympathetic superior cervical ganglion and the sensory trigeminal ganglion. The number of labelled neurons in the cervical superior ganglion varied according to the survival time with peak labelling occurring after 48 h. Sparse labelling of the sensory trigeminal ganglion was also present after 48 h. The results indicate that sympathetic neurons from the superior cervical ganglion and to a certain extent trigeminal somatosensory neurons innervate the ES or perisaccular tissue. If these findings reflect the existence of a sympathetic functional reflex unit remains to be elucidated.

Perforation of the Oesophagus :A Comparison between Surgical and Conservative Treatment

A series of 48 patients with oesophageal perforations was reviewed retrospectively. Eighty-seven per cent of the perforations were iatrogenic. Twenty-four patients were treated conservatively; 3 of this group died. The other 24 patients were treated surgically and 4 of them died. Patients with alarming symptoms and/or a large perforation underwent operative treatment unless there were contra-indications. Retained foreign bodies after perforation, and malignancy in the perforation area, were considered as indications for operation. Conservative treatment was reserved for patients with minor tears combined with a less turbulent course. The interval between perforation and therapy was not of decisive importance for the mortality in our series. The clinical picture, which was dominated by chest pain, gave the earliest indication of perforation, while the responses of the sedimentation rate, temperature and white blood count occurred later and were less reliable diagnostic signs.

Effects of Hyperosmolar Substances on the Endolymphatic Sac

The murine endolymphatic sac (ES) was studied 15 min to 8 hours after intravenous glycerol administration. Initially the ES showed varying degrees of obliteration and this was mostly pronounced at 15-60 min after the injection. After 2 hours the normal volume was regained and after 4 hours the lumen was dilated to 160% of its normal volume. After 6-8 hours the ES had almost regained its normal appearance. The epithelial lining showed an increase in the number of granular cells which, after two hours, reached a peak of 15.8% (p less than 0.01) compared to normal controls which showed 6.1% granular cells of total cell population in the ES. The increase of granular cells was accompanied by filling of the ES lumen with a stainable substance. The epithelial reaction may serve the purpose of counteracting decreases in endolymph pressure either in the ES or in the entire labyrinth.

Embryonic and postnatal accumulation of homogeneous substance in the endolymphatic sac in the guinea pig

OBJECTIVE The endolymphatic sac (ES) of vertebrates contains varying amounts of a homogeneous substance (HS) that stains deeply with basic aniline dyes. Histochemically, HS is characterized as a carbohydrate-protein complex, being both neutral and acidic in nature. In the present study, deposition of HS in the ES was studied in the guinea pig from the 3rd week of gestation to 104 weeks postnatally in order to find out if HS accumulates with age, at which point during embryonic development this substance appears, if its presence is correlated to the sense of hearing and if the amount of substance in the left versus right ear of one and the same animal is correlated to any degree. METHODS Sixty-nine endolymphatic sacs were evaluated in 38 guinea pigs. The ES specimens were sectioned for light and transmission electron microscopy and the amount of HS filling was categorized in four groups: none, low, medium and a high level of substance. RESULTS The substance was not discerned until after 7 weeks of gestation, when it filled only a minor part of the distal ES lumen. At 9 weeks gestation the nature of the substance altered, becoming homogeneous, as visualized by osmium-toluidine blue staining and approximately filling the distal half of the luminal space. In the postnatal period, 65% of ES specimens were filled with HS to the intermediate or proximal ES, whereas only 6.5% of the ES specimens were devoid of the substance. The extent of filling of the ES in the prenatal temporal bones was significantly less than postnatally (P < 0.0001, chi2-test). The extent of postnatal filling was not correlated with age. Left and right ears were closely correlated in one and the same animal. Phagocytic cells were often found at the border between clear endolymph and stainable substance. CONCLUSION The appearance of HS seemed to coincide temporally with the onset of hearing during the prenatal period indicating that it could play a part in normal inner ear functioning in the guinea pig. The close correlation regarding the level of the HS in the left and right ear, both pre- and postnatally could reflect a general symmetry in endolymph pressure-volume conditions within the inner ear fluid systems, as well as in the environmental hydrostatic pressure in the posterior cranial fossa.