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We present an automatic lung lobe segmentation algorithm for COPD patients. The method enhances fissures, removes unlikely fissure candidates, after which a B-spline is fitted iteratively through the remaining candidate objects. The iterative fitting approach circumvents the need to classify each object as being part of the fissure or being noise, and allows the fissure to be detected in multiple disconnected parts. This property is beneficial for good performance in patient data, containing incomplete and disease-affected fissures. The proposed algorithm is tested on 22 COPD patients, resulting in accurate lobe-based densitometry, and a median overlap of the fissure (defined 3 voxels wide) with an expert ground truth of 0.65, 0.54 and 0.44 for the three main fissures. This compares to complete lobe overlaps of 0.99, 0.98, 0.98, 0.97 and 0.87 for the five main lobes, showing promise for lobe segmentation on data of patients with moderate to severe COPD.

The Capital Hip implant was a Charnley-based system which included a flanged and a roundback stem, both of which were available in stainless steel and titanium. The system was withdrawn from the market because of its inferior performance. However, all four of the designs did not produce poor rates of survival. Using a simulated-based, finite-element analysis, we have analysed the Capital Hip system. Our aim was to investigate whether our simulation was able to detect differences which could account for the varying survival between the Capital Hip designs, thereby further validating the simulation.We created finite-element models of reconstructions with the flanged and roundback Capital Hips. A loading history was applied representing normal walking and stair-climbing, while we monitored the formation of fatigue cracks in the cement.Corresponding to the clinical findings, our simulation was able to detect the negative effects of the titanium material and the flanged design in the Capital Hip system. Although improvements could be made by including the effect of the roughness of the surface of the stem, our study increased the value of the model as a predictive tool for determining failure of an implant.

Objective:The aim of this study was to analyze a possible contribution of human neutrophil defensins and secretory leukocyte proteinase inhibitor (SLPI) to the induction of airway epithelial changes such as squamous cell metaplasia. Materials and methods:The presence of these molecules and the number of proliferating (Ki-67-positive) epithelial cells was analyzed by immunohistochemistry in bronchial epithelium from subjects with (n = 15) or without (n = 14) chronic obstructive pulmonary disease (COPD). Results:Our data demonstrate higher numbers of defensin-positive (p = 0.0001), elastase-positive (p = 0.0001) and Ki-67-positive (p = 0.0001) cells in areas with squamous cell metaplasia as compared to areas with intact or damaged epithelium, while the reverse was observed for SLPI expression (p = 0.002). No differences were observed between subjects with or without COPD, nor between current smokers and those that had stopped smoking. Conclusions:These data are in line with a role of defensins in the hyperproliferative phenotype of squamous metaplastic lesions in the airways. This role does not seem to be restricted to patients with COPD.

Background It has been suggested that oxidative stress is an important factor in the pathogenesis of chronic obstructive pulmonary disease (COPD). We have shown that an oxidant/antioxidant imbalance occurs in the distal air spaces of smokers and in patients with COPD which is reflected systemically in the plasma. A study was undertaken to determine whether plasma antioxidant status correlated with lung function as assessed by forced expiratory volume in one second (FEV₁) and forced vital capacity (FVC) in smokers and patients with COPD. Methods Plasma antioxidant capacity, assessed by the Trolox equivalent antioxidant capacity (TEAC) as an index of overall systemic oxidative stress, and protein thiol levels were measured in 95 patients with stable COPD, in 82 healthy smokers, and in 37 healthy non-smokers. Results Mean (SE) plasma TEAC levels were significantly decreased in patients with COPD (0.81 (0.03) mmol/l, p<0.001) and in healthy smokers (0.87 (0.04) mmol/l, p<0.001) compared with healthy non-smokers (1.31 (0.11) mmol/l). The mean differences in plasma antioxidant capacity (mM) were (0.81, 95% confidence interval (CI) 0.22 to 1.48), (0.87, 95% CI 0.2 to 1.46), and (1.31, 95% CI 1.09 to 1.58) in patients with COPD, healthy smokers, and healthy non-smokers, respectively. This reduction was associated with a 29% (95% CI 18 to 38) and a 30% (95% CI 19 to 40) decrease in plasma protein thiol levels in COPD patients and smokers, respectively. Current smoking was not the main contributor to the reduction in antioxidant capacity in patients with COPD as those patients who were still smokers had similar TEAC levels (mean (SE) 0.78 (0.05); n = 25) to those who had stopped smoking (0.84 (0.02); n = 70). No significant correlations were found between spirometric data measured as FEV₁ % predicted or FEV₁/FVC % predicted and the plasma levels of TEAC in patients with COPD, healthy smokers, or healthy non-smokers. Similarly, there was no significant correlation between FEV₁ % predicted or FEV₁/FVC % predicted and the levels of plasma protein thiols in the three groups. Conclusions These data confirm decreased antioxidant capacity in smokers and patients with COPD, indicating the presence of systemic oxidative stress. However, no relationship was found between protein thiols or TEAC levels and measurements of airflow limitation in either smokers or in patients with COPD.

One hundred eight human ovarian cancers were analyzed for estrogen (ER), progestin (PgR), and androgen (AR) receptors. The receptor levels were related to histological type and grade of the tumor. There were 103 common epithelial carcinomas subdivided into serous (36), endometrioid (36), mucinous (18), clear cell (5), malignant Brenner (3), mixed epithelial (2), and undifferentiated (3) types. Of the remaining five, four were sex cord-stromal tumors and there was a single case of germ cell tumor. ER was detected in 52, PgR in 52, and AR in 91 of the cases. There was no correlation between the presence of ER and AR and the tumor histology. The presence of PgR correlated with the grade of endometrioid carcinoma, while no clear correlation existed for the other tumor types. PgR was absent in the three undifferentiated carcinomas. Interestingly, high PgR levels were detected in the three granulosa cell tumors.

Summary: Secretory leukocyte inhibitor (SLPI) is a potent inhibitor of serine proteinases, but sensitive to oxidative inactivation due to a methionine residue in the active centre of the inhibitor. We compared the potency of an oxidation-resistant mutant of recombinant SLPI with native recombinant SLPI in lipopolysaccharide (LPS)-induced emphysema in the hamster. Application of this oxidation-resistant mutant reduced the induced emphysema by 70 and 85% in two separate series of experiments. In contrast, an equal amount of native rSLPI resulted in significantly lower inhibition, 30 and 23%, respectively (P=0.002). To demonstrate the effect of oxygen radicals upon a single LPS instillation in the lungs, we measured anti-neutrophil elastase activity in lung lavage fluid at 10 and 24 h after the instillation of a mixture of LPS and native rSLPI. We found that residual native rSLPI was only 70 and 55% active, respectively. The rSLPI-mutant remained 93% active in a similar experiment. The native and mutant inhibitor showed equal potency against proteinases in a granule extract of hamster neutrophils. We conclude that the replacement of methionine by leucine in the inhibitory centre of rSLPI results in a decreased sensitivity to oxidative inactivation and that this alone is sufficient to explain the greater efficiency of the rSLPI-mutant in reducing the extent of LPS-induced emphysema. Copyright 1993, 1999 Academic Press

rTNFα facilitates highly reproducible adherence of polymorphonuclear leukocyte (PMN) to fibrinogen‐coated surfaces in a concentration‐ and time‐dependent manner. The adhesion was maximal with 1.0 nM rTNFα within 40–50 min at 37°C. A monoclonal antibody (1B4) directed toward the β2‐chain of the integrin receptor for fibrinogen (CD11b, CD18) completely inhibited the rTNFα induced adhesion. TNFα caused a time‐dependent secretion of the granule markers gelatinase and lactoferrin but no liberation of myeloperoxidase and minimal production of Aα(1–21), a specific cleavage product of fibrinogen generated by elastase, as markers for the azurophilic granule. PMN adhered to fibrinogen in the presence of rTNFα could be further stimulated with cytochalasin B and N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP) to release azurophilic granule markers as measured by increasing MPO activity and Aα(1–21) production over time. Thus the rTNFα‐facilitated adherence of PMN to a fibrinogen matrix provides a system for partial activation of PMN resulting in release of markers of specific and tertiary but not azurophilic granules. Moreover, these conditions should provide an opportunity to define more clearly the signal transduction processes involved in azurophilic granule release.

The metabolic clearance rate (MCR) of both bovine and rat dopamine beta-hydroxylase (DBH) preparations was measured using two complementary procedures, pulse-dose injection and constant infusion of enzyme into the rat circulation. Rats that received injections of DBH activity had plasma DBH activity levels similar to those of controls by 24 hr after a pulse dose of rat DBH. The DBH MCR computed by stochastic analysis of the disappearance curve of injected DBH activity was about 1.0 ml/hr/100 g body weight; the mean transit time of DBH was about 8 hr. The disappearance curve of heterologous enzyme (bovine DBH) was more rapid than that of the rat, yielding an MCR of about 8 ml/hr/100 g body weight. MCR values obtained with the constant-infusion technique were similar to those obtained with the pulse-dose technique. These kinetic parameters are consistent with the time frame for altered plasma DBH activity observed with pharmacological and endocrinological factors. These data support the conclusion that plasma DBH turnover time is measured in hours, not days.

The potential role of brain adrenergic neurons in regulating noradrenergic neuronal metabolism was assessed using inhibitors of phenylethanolamine N-methyltransferase (PNMT), the enzyme responsible for epinephrine production. Two centrally active PNMT inhibitors (SK&F 64139 and LY134046) were administered over a 6-day treatment period to cause prolonged reductions in epinephrine formation. In brain regions containing endogenous epinephrine (medulla-pons and hypothalamus), chronic treatment with PNMT inhibitors produced: 1) reductions of epinephrine content, 2) elevation of tyrosine hydroxylase activity and 3) elevation of alpha-1 and particularly alpha-2 adrenergic receptor radioligand binding sites; neither norepinephrine turnover nor beta adrenergic receptor binding was affected. In brain regions devoid of endogenous epinephrine (cerebellum, frontal cortex and hippocampus), chronic treatment with PNMT inhibitors produced 1) a variable increase in tyrosine hydroxylase activity (cerebellum only) and 2) a reduction in norepinephrine turnover; neither alpha or beta adrenergic receptor binding was altered. A PNMT inhibitor failing to cross the blood-brain barrier, SK&F 29661, and an alpha-1 adrenoceptor antagonist, prazosin, had no effect on brain catecholamine metabolism. High doses of an alpha-2 adrenoceptor antagonist, yohimbine, increased medulla-pons tyrosine hydroxylase activity but also resulted in prominent reductions in norepinephrine content in all brain regions. The results suggest that prolonged reductions in endogenous brain epinephrine formation produce unique effects on brain norepinephrine function; these effects are regionally distinctive and are qualitatively different from the effects seen with chronic alpha-1 or alpha-2 adrenergic receptor blockade. These data are consistent with regulation of brainstem norepinephrine-containing cell bodies by endogenous adrenergic systems, probably via medullary-pontine alpha-2 adrenergic receptors.

It is difficult to predict the possible development of a malignant trophoblastic tumor after the evacuation of a hydatidiform mole. In order to help resolve this difficulty, a morphometric study has been carried out. The mean nuclear area of the trophoblast in a group of hydatidiform moles, followed by a trophoblastic malignancy, was found to be statistically significantly larger than that of the trophoblast in a group of hydatidiform moles which were not followed by malignant trophoblastic disease. However, the mean trophoblast/nontrophoblast ratio in villi demonstrated no statistically significant difference between those 2 groups of hydatidiform moles. Therefore it is not advisable to grade hydatidiform moles on the basis of trophoblastic proliferation alone.

The catecholamine-synthesizing enzymes, tyrosine hydroxylase, dopamine-ß-hydroxylase and phenylethanolamine-N-methyltransferase were examined by immunohistochemistry in hypertrophied paraganglia of aged male Fischer-344 rats. All paraganglionic cells reacted with antibodies against tyrosine hydroxylase. Dopamine ß-hydroxylase was identified in most paraganglionic cells, indicating that they synthesized norepinephrine. A variable number of paraganglia were positive for phenylethanolamine-N-methyltransferase, which suggested that they synthesized epinephrine. The formaldehyde-induced fluorescence method demonstrated greenish-yellow fluorescence or yellowish-brown fluorescence. The intensity of the fluorescence was in the same range as in adrenal medullary cells. The observations indicate that paraganglia are capable of synthesizing epinephrine.

Upon stimulation, polymorphonuclear leucocytes (PMNs) release potent serine proteases, i.e. elastase, cathepsin G and proteinase 3, which contribute to the degradation of tissue and plasma components. Here, we describe the development of a plasma test to assess PMN-mediated fibrinogenolysis as a biochemical marker for actual PMN-derived proteolysis in vivo, useful for monitoring therapeutic efficacy, i.e. of elastase inhibitors. We generated a monoclonal antibody (MAb), designated 1-1/B3, with a high affinity for elastase-degraded fibrinogen (EDF). The epitope for 1-1/B3 becomes exposed in a time-dependent manner during digestion of fibrinogen with purified PMN-derived serine proteases and with isolated PMNs in vitro. However, 1-1/B3 does not react with plasma fibrinogen or with fibrin(ogen) degradation products generated by plasmin or by other active proteases that may occur locally, i.e. metalloproteases and lysosomal cathepsins. On the basis of MAb 1-1/B3, we developed a plasma test for the assessment of PMN-mediated fibrin(ogen) degradation products (PMN-FDP). In a panel of control plasmas, we observed concentrations of PMN-FDP of 8.2 ± 0.9 ng mL-1 (n = 18). These values were increased twofold in patients with alpha1-proteinase inhibitor deficiency (18.6 ± 3.3 ng mL-1; n = 12; P < 0.0001) and even more in patients with sepsis (365.7 ± 97.7 ng mL-1; n = 16; P < 0.0001). Furthermore, synovial tissue extracts from patients with rheumatoid arthritis contained increased levels of PMN-FDP, compared with synovial tissue extracts (P < 0.005) from patients with osteoarthritis.

Circulatory dopamine-beta-hydroxylase (DBH) activity was increased as much as 6-fold in rats with streptozotocin-induced diabetes mellitus. The increased enzymatic activity correlated with increased DBH protein as assessed by neutralization with homologous antiserum. The high levels of circulating DBH activity induced by streptozotocin was associated with a markedly slowed disappearance of enzyme activity after the i.v. injection of exogenous bovine DBH or exogenous rat DBH. Treatment of streptozotocin-treated rats with insulin prevented the increase in circulating DBH activity and reduced the initial half-time of disappearance of bovine DBH in a dose-related manner; the correlation between the initial half-time of disappearance of the bovine enzyme and the circulating DBH activity level was strongly positive. These results indicate that a reduction in the metabolic clearance rate of circulating DBH is a major factor accounting for the increase in serum DBH activity in the streptozotocin-diabetic rat.

Morphological changes are described in pelvic lymph nodes excised 10 days after C. parvum (CP) treatment of patients with cervical carcinoma. Guinea-pig popliteal and inguinal lymph nodes were investigated from Days 1 to 10 after an injection of 70 micrograms CP into the footpad. Eosinophils were detected from the first few hours after stimulation, initially in the marginal sinus, then in the medullary sinuses and subsequently in the efferent lymphatics. From Day 2 to Day 6, histiocyte accumulations with the appearance of epithelioid cells were found mainly in subcapsular and interfollicular areas, and small granulomas were also seen in the paracortex. The granuloma formation in the lymph node was considered as an indication of the activation of histiocytes. Besides small granulomas in the paracortex, activated interdigitating cells, surrounded by scattered lymphoblasts and eosinophils, were also present. We considered this lymphoblastic response and eosinophilic accumulation as likely to be due to blastogenic factor and eosinophil stimulation promotor. Eight to 10 days after CP stimulation, the macrophage lymphoblast eosinophil response was replaced by a B-cell reaction: germinal-centre activation and medullary plasma cells. Such a B-cell reaction was also found in the human pelvic nodes removed at operation, but this reaction could not be attributed to CP treatment alone, since cervical-carcinoma patients not treated with CP also showed such reactions. In contrast, pelvic lymph nodes removed at necropsy from females killed in traffic accidents showed no predominance of either B- or T-cell stimulation.

The effect of adjuvant immunotherapy with a single neighbourhood injection of 2 mg C. parvum (CP) was investigated in a randomized study involving 43 patients with carcinoma of the cervix uteri, all of whom were treated by radical surgery. All patients had carcinoma confined to the cervix, the upper part of the vagina or the parametrial region. When the malignancy had spread to the parametrial region, additional postoperative radiotherapy was given. 22 patients received immunotherapy 10 days before surgery, whereas the remaining 21 control patients received no immune stimulation. Only minor side effects of CP were encountered. Follow-up shows a relapse rate of 5% in the CP treated group and of 29% in the controls (P less than 0.05). A further 15 patients with more advanced malignancies were added to our studies. In these, CP stimulation had no effect on relapse rates, but the relapse-free intervals were longer after immune stimulation: control 3.5 months (mean) +/- 1.5 (s.d.), CP 13.0 months +/- 7.0 (P less than 0.05). The number of peripheral T cells and the ability to become sensitized to DNCB were increased after CP stimulation. A decrease was found in the number of blood monocytes and the number of monocytes capable of transforming into active macrophages, indicating a possible sequestration of these cells in the tissues.

In earlier experiments we showed that locally administeredCorynebcicterium parvum (C. parvum)stimulated the T-cell system and had a beneficial effect on the recurrence rate of surgically resected cancers of the uterine cervix. In this paper we report the use of an immunoperoxidase technique to traceC. parvumantigen in the draining lymph nodes. In a guinea pig model the popliteal lymph node was studied after the injection of 70 μg ofC. parvumin the hind footpad. At 6 h, intact bacteria were detected in sinus histiocytes. A transient granuloma formation was apparent between days 2 and 6, originating in the subcapsular and interfollicular areas. Three antigen-positive cell types were observed in these granulomas: a) cytophagocytic macrophages which were weakly positive, the antigen being distributed in clumps; b) dendritic cells with a strong, fine-granular positivity and c) some epithelioid cells with a small positive cytoplasmic rim. The majority of epithelioid cells was negative. Antigen-positive dendritic cells were also observed just beyond the granulomas in the T-dependent paracortical area. These cells are known as interdigitating cells (IDC) and present antigen to T-cells. Ten days followingC. parvuminjection the lymph node follicles became positive and the antigen could be detected in the long cellular protrusions of the dendritic reticulum cells (DRC). DRC probably play a part in immunological memory by trapping antigen in the form of immune complexes.

Antileukoprotease (ALP), or secretory leukocyte proteinase inhibitor, is an endogenous inhibitor of serine proteinases that is present in various external secretions. ALP, one of the major inhibitors of serine proteinases present in the human lung, is a potent reversible inhibitor of elastase and, to a lesser extent, of cathepsin G. In equine neutrophils, an antimicrobial polypeptide that has some of the characteristics of ALP has been identified (M. A. Couto, S. S. L. Harwig, J. S. Cullor, J. P. Hughes, and R. I. Lehrer, Infect. Immun. 60:5042-5047, 1992). This report, together with the cationic nature of ALP, led us to investigate the antimicrobial activity of ALP. ALP was shown to display marked in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus. On a molar basis, the activity of ALP was lower than that of two other cationic antimicrobial polypeptides, lysozyme and defensin. ALP comprises two homologous domains: its proteinase-inhibitory activities are known to be located in the second COOH-terminal domain, and the function of its first NH2-terminal domain is largely unknown. Incubation of intact ALP or its isolated first domain with E. coli or S. aureus resulted in killing of these bacteria, whereas its second domain displayed very little antibacterial activity. Together these data suggest a putative antimicrobial role for the first domain of ALP and indicate that its antimicrobial activity may equip ALP to contribute to host defense against infection.

Serum contains many growth factors and nutrients that stimulate colony formation of hematopoietic progenitor cells (HPC) in semisolid cultures. In the absence of serum, no proliferation of HPCs could be obtained in semisolid medium cultures of partially purified bone marrow cells in the presence of multiple hematopoietic growth factors, insulin, cholesterol, and purified clinical-grade human albumin. This appeared to be due to a suppressive activity induced by monocyte- and T lymphocyte-depleted accessory cells on CD34+ HPCs. Serum-free conditioned medium from the bladder carcinoma cellline 5637 could replace serum to support the growth of HPCs in these cultures. After gel filtration and reverse-phase high-performance liquid chromatography of 5637 supernatants, this activity could be attributed to a 15-kD protein that was further identified by NH2-terminal sequence analysis as the serine proteinase inhibitor antileukoproteinase (ALP). The growth-supportive activity from the 5637 conditioned medium and the (partially) purified fractions could be completely neutralized by a polyclonal rabbit IgG antibody against human ALP (huALP). Similar supportive effects on the growth of HPC could be obtained in the presence of recombinant huALP. We demonstrated that the COOH-terminal domain of ALP containing the proteinase inhibitory activity was responsible for this effect. alpha-1 proteinase inhibitor was capable of similar support of in vitro HPC growth. These results illustrate that proteinase inhibitors play an important role in the in vitro growth of hematopoietic cells by the neutralization of proteinases produced by bone marrow accessory cells. This may be of particular relevance for in vitro expansion of human hematopoietic stem cells in serum-free media.

Antileukoprotease (ALP), or secretory leukocyte proteinase inhibitor, is an endogenous inhibitor of serine proteinases that is present in various external secretions. ALP, one of the major inhibitors of serine proteinases present in the human lung, is a potent reversible inhibitor of elastase and, to a lesser extent, of cathepsin G. In equine neutrophils, an antimicrobial polypeptide that has some of the characteristics of ALP has been identified (M. A. Couto, S. S. L. Harwig, J. S. Cullor, J. P. Hughes, and R. I. Lehrer, Infect. Immun. 60:5042-5047, 1992). This report, together with the cationic nature of ALP, led us to investigate the antimicrobial activity of ALP. ALP was shown to display marked in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus. On a molar basis, the activity of ALP was lower than that of two other cationic antimicrobial polypeptides, lysozyme and defensin. ALP comprises two homologous domains: its proteinase-inhibitory activities are known to be located in the second COOH-terminal domain, and the function of its first NH2-terminal domain is largely unknown. Incubation of intact ALP or its isolated first domain with E. coli or S. aureus resulted in killing of these bacteria, whereas its second domain displayed very little antibacterial activity. Together these data suggest a putative antimicrobial role for the first domain of ALP and indicate that its antimicrobial activity may equip ALP to contribute to host defense against infection.

SR proteins are a family of proteins that have a common epitope recognized by a monoclonal antibody (MAb104) that binds active sites of polymerase II transcription. Four of the SR family members have been shown to restore activity to an otherwise splicing-deficient extract (S100 extract). Here we show that two untested SR proteins, SRp20 and SRp75, can also complement the splicing-deficient extract. We isolated a cDNA encoding SRp75 and found that this protein, like other SR proteins, contains an N-terminal RNA recognition motif (RRM), a glycine-rich region, an internal region homologous to the RRM, and a long (315-amino-acid) C-terminal domain composed predominantly of alternating serine and arginine residues. The apparent molecular mass of dephosphorylated SRp75 is 57 kDa, the size predicted from the cDNA clone. We also detected mobility shifts after dephosphorylating SRp55, SRp40, SRp30a, and SRp30b; the sizes of the shifts are proportional to the length of the SR domain, suggesting that serines in this domain are phosphorylated.

An antibody was identified previously that recognizes sites of polymerase II transcription on lampbrush chromosomes, puffs on polytene chromosomes, and many small granules in the nucleoplasm of all cells tested. This antibody binds a conserved family of phosphorylated polypeptides in vertebrate and invertebrate cells. We developed a method for purifying these proteins that involves differential solubility in MgCl2. We isolated a Drosophila cDNA encoding one of the proteins using information obtained from microsequencing. In vivo expression studies show that this protein is concentrated on sites of polymerase II transcription and that it is highly phosphorylated. The protein shares a high degree of homology with proteins involved in alternative splicing of pre-mRNA suggesting the possibility that this protein plays a role in pre-mRNA splicing.

1. Ozone is a major constituent of air pollution in the summer. Epidemiological studies have demonstrated that there is an increase in hospital admissions for respiratory diseases 1 day after peak levels of ambient ozone. This may be due to an increase in the responsiveness of the airways to bronchoconstrictor stimuli. 2. In the present study we therefore studied the effect of a controlled exposure to ozone on the maximal degree of airway narrowing to a non-specific bronchoconstrictor, methacholine, 12 h after exposure. Both non-asthmatic and mild-asthmatic volunteers were exposed to ozone. 3. The study had a single blind design. Experimental exposures were to filtered air, 0.40 ppm ozone and filtered air respectively, at 1-week intervals. The duration of each exposure was 2 h with alternating periods of 15 min rest and exercise. At 12 h after exposure, methacholine inhalation challenge tests and sputum induction were performed. 4. Twelve hours after exposure to ozone there was a significant increase in the maximal degree of airway narrowing to methacholine (P < 0.02) compared with exposure to air, in non-asthmatic as well as asthmatic subjects. These physiological changes were accompanied by a significant rise in the percentage of neutrophils in induced sputum (P < 0.02). All changes had returned to baseline values 1 week after exposure to ozone. 5. Exposure to ozone causes a transient increase in the maximal degree of airway narrowing to methacholine in both non-asthmatic and asthmatic subjects. These laboratory results, obtained using relatively high ozone exposure in carefully selected subjects, might provide an explanation for the temporal relationship between ambient ozone levels and hospital admissions for asthma.

Transtracheal oxygen delivery seems to be a safe procedure in the treatment of chronic obstructive pulmonary disease (COPD) with chronic hypoxaemia. Even so, serious complications do occur. Three patients in whom we used a subcutaneous tunnelled intratracheal oxygen catheter (ITO2C) are described. Surgical intervention was required in all because of complications from the procedure. One of the complications—tracheal and catheter obstruction with stridor and subcutaneous emphysema by granulomatous tissue—has to our knowledge not been reported before.