Lung cell reactions in guinea pigs after inhalation of asbestos (amosite)

To study the long-term effect of inhaled asbestos, guinea-pigs were exposed to airborne amosite at a concentration of 49 mg/m3, 2 h/day for 3 or 6 weeks and examined up to 2 years after exposure. Macrophages in lung lavage fluid (LLF) were increased at 16, 24 and 93 weeks and lymphocytes at 24 weeks. Examination of lung wall cells (LWC) 2 years after exposure compared to cells obtained by LLF showed higher proportions of LWC lymphocytes and neutrophils. Percoll gradient centrifugation of these cells showed a higher proportion of high density macrophages in LLF from the amosite-exposed animal and an increased number of low density lymphocytes in the LW. Cathepsin D was increased in LLF at 8 and 24 weeks and in alveolar macrophages 24 weeks and 2 years after exposure. Fibroblast cultures exposed to LLF did not show any statistical significant changes in their collagen synthesis. Histology 93 weeks after exposure showed macrophage and mediastinal lymph node accumulation of asbestos, as well as collagen in alveolar walls. Granulomas were found in the vicinity of blood vessels and in connection with the bronchioles. The data suggest that amosite at low doses ultimately causes fibrosis with a reaction pattern different from that seen in silicosis. The inflammation and fibrosis seems to develop only within the interstitium.     

Contrast sensitivity and acuity relationship in strabismic and anisometropic amblyopia.

The contrast sensitivity function (CSF) and visual acuity were determined in children and adults with unilateral amblyopia due to strabismus or anisometropia with central fixation. The preschool children were examined repeatedly during occlusion treatment. All amblyopes had CSF deficits. The CSF was characterised by its peak value (the maximal sensitivity, Smax, and the spatial frequency at which Smax occurs, Frmax) calculated by a single peak least-square regression method. The two amblyopic groups showed discrepancies in relationship of both Smax and Frmax versus visual acuity both initially and during treatment. The strabismic cases had a more marked visual acuity deficit in relation to the contrast sensitivity losses, whereas these parameters are affected similarly in anisometropic amblyopes. The relationship between recovery of visual acuity and CSF during the initial month of occlusion treatment was of prognostic significance for the outcome of visual acuity improvement.     

Bronchial hyperresponsiveness, epithelial damage, and airway eosinophilia after single and repeated allergen exposure in a rat model of anhydride-induced asthma

Bronchial hyperresponsiveness (BHR) and damage of the epithelium, as well as eosinophilia in the airway wall, induced by trimellitic anhydride (TMA) in sensitized brown Norway rats were studied. Rats were challenged once or seven times with aerosol of TMA conjugated to rat serum albumin (TMA-RSA) 3 weeks after intradermal TMA sensitization. Airway responsiveness (-log PC₃₀₀ of acetylcholine i.v.) was measured 24 h after allergen challenge. Epithelial lesion and eosinophil infiltration in the airway walls were quantified under light microscopy, and TMA-specific IgE and IgG in serum were evaluated with ELISA. High levels of TMA-specific IgE and IgG were found in all rats in the sensitized groups compared to nonsensitized groups ( P < 0.001). Repeated allergen challenges of 0.03% TMA-RSA for 7 consecutive days enhanced the level of TMA-specific IgG, compared to single challenge ( P < 0.05). Single allergen challenge of 0.3% TMA-RSA had a nonsignificant tendency to produce BHR in sensitized rats compared to nonsensitized rats ( P =0.06). However, repeated allergen challenges (0.003% and 0.03% TMA-RSA for 7 consecutive days) produced significant BHR in sensitized rats ( P < 0.05). Furthermore, repeated low-dose (0.003%) TMA-RSA challenge produced more BHR than a 10 times higher single dose (0.03%) ( P < 0.05). Slight damage of the airway epithelium was seen in sensitized and repeat-challenged groups. However, bronchial eosinophilia was found in the sensitized and single-challenged groups, but not in nonsensitized nonchallenged, and sensitized repeat-challenged groups ( P < 0.005). We conclude that the brown Norway rat can be sensitized with TMA, and that repeated low-dose allergen challenges produce slight epithelial damage and BHR which is independent of ongoing eosinophilia in the airway wall.     

Die funktionelle Bedeutung des Ultrafeinbaues von Gewebezellen

Ohne Zusammenfassung     

Mast cell myositis: a new feature of allergic asthma?

There is some evidence that, in asthma, mast cells infiltrate the airway smooth muscle layer and, as a consequence, alter the functional and structural properties of myocytes. This inflammation so-called mast-cell myositis, probably contributes to both bronchial hyperresponsiveness and airway remodelling. Previous observations have pointed out the presence of mast cells within airway smooth muscle of atopic patients and recent data obtained in asthmatic patients demonstrate that this infiltration is more important in asthmatic patients with atopy. Although the mechanism of such a mast cell attraction remains to be fully understood, experimental data demonstrate that, upon stimulation by tryptase or cytokines, smooth muscle cells can attract mast cells through the production of TGF-beta1 or SCF. Once at the site of inflammation, activated mast cells are responsible for an important extracellular deposition of inflammatory products that may facilitate the increase in smooth muscle mass. In addition, comparison of asthmatic patients with and without atopy suggests that mast cell myositis is closely related with atopy.     

Suprathreshold vision in acute optic neuritis.

The perception of contrast was measured in patients with acute unilateral optic neuritis by a technique of subjective suprathreshold contrast matching, and was compared with contrast sensitivity as defined by threshold measurements. The suprathreshold apparent contrast and threshold contrast sensitivity was repeatedly assessed during the recovery phase. Generally, an attenuation of suprathreshold apparent contrast was found for high and intermediate spatial frequencies in the eye with optic neuritis. At a low spatial frequency, however, the suprathreshold contrast vision was spared. The threshold contrast sensitivity was not however, spared at low spatial frequencies. During recovery this frequency-specific loss in suprathreshold apparent contrast diminished and finally a "normal" suprathreshold contrast vision was observed in all affected eyes reaching a visual acuity of 1.0 or better. In these cases also subjectively normal vision was reported in site of a persisting abnormality in threshold contrast sensitivity.     

Thoracic epidural analgesia as an adjunct to general anaesthesia for cardiac surgery. Effects on pulmonary mechanics

BACKGROUND: A lasting impairment of pulmonary function is common after cardiac surgery. Pain from the sternotomy may contribute to the impairment. Thoracic epidural analgesia (TEA) can efficiently relieve pain in the postoperative phase, but may also affect respiratory muscle function if local anaesthetics are used. We examined the effects of TEA on pulmonary function and ventilation at rest, before and after coronary artery bypass graft surgery (CABG). METHODS: Thirty patients scheduled for CABG were randomized to receive either general anaesthesia alone or general anaesthesia with TEA. Before and after the operation the patients were examined by respiratory inductive plethysmography and spirometric tests. RESULTS: Before the operation, TEA caused significant reductions in forced vital capacity (FVC), forced expired volume in 1 s (FEV1), maximal inspiratory (PImax) and expiratory (PEmax) pressure. The rib cage contribution to tidal volume decreased significantly but the co-ordination of the thoracic and abdominal movements remained essentially unaffected. Minute volume and respiratory frequency did not change significantly. On the first postoperative day a decrease in maximal breathing efforts was found in both groups. No differences between the groups in FVC, FEV1 and PImax were found, but PEmax was significantly greater in the TEA group. Despite the impairment, breathing at rest was largely normal in both groups. CONCLUSIONS: A better pain-relief from TEA after CABG may improve the ability to cough by a greater expiratory muscle strength. FVC, FEV1, PImax and breathing at rest are not affected by TEA after cardiac surgery.