Evaluating the penetration of Cladosporium spores into the human respiratory system on the basis of aerobiological sampling results

The penetration of Cladosporium spores and spore aggregates into human airways was studied using three different spore sampling methods: 1) a Burkard spore trap for determining the aggregation degree of Cladosporium; two samplers, simulating the human respiratory system, 2) a 6-stage Andersen 2000 sampler, and 3) a new size-selective bioaerosol sampler (SSBAS), designed specifically for immunochemical and chemical analyses. The aggregation degree of Cladosporium spores varied between 1.0 and 1.3 spores per dispersal unit. Grouping seems to be of little if any importance to the penetration ability of Cladosporium spores into the respiratory tract. The distribution of spores in the Andersen and SSBAS differed significantly in the largest size class (spores greater than 7 microns in diameter); with the Andersen sampler only 10.8% of the spores were detected in stage 1, compared with 43% with the SSBAS. On the Andersen culture plates 95% of all colonies were detected in stages 1-4, where particles greater than 2.1 microns in diameter are trapped. In the SSBAS altogether 99.4% of spores were found in the first two filter stages (cutoff point approx. 2.5 microns in diameter). Conclusions regarding the penetration of spores to the lungs on the basis of aerobiological results should always be based on the use of properly calibrated spore traps.     

Pulmonary immune responses to Nippostrongylus brasiliensis: isotype-specific antibodies in bronchoalveolar lavage fluids of rats

Larvae of Nippostrongylus brasiliensis have an obligatory migratory phase through the lungs of rats during their development. Since earlier studies have shown that this migration is associated with accumulation of Fc receptor bearing effector cells in the bronchoalveolar spaces, wc have analysed antibody reactivity in bronchoalveolar lavage fluids (BALF) during development of immune responses against N. brasiliensis. The development of parasite specific antibodies in bronchoalveolar spaces was similar to that in the serum, but was of a lower titre. A secondary infection resulted in an anamnestic response. Iso type analysis showed that IgG, IgA and IgM antibodies were present in BALF and they recognized several proteins of the parasite ranging from 16-290 kDa. Immunoblot analysis on two-dimensional electrophoretic separated parasitic proteins identified stage specific differences in the BALF antibody responses. IgG was the predominant class of antibody in BALF and when compared with serum, IgM antibody responses were weak. Thus, infection with N. brasiliensis resulted in the appearance of site-, stage- and isotype-specific antibody responses in the lungs of rats.     

Circulating megakaryocytes: Delivery of large numbers of intact,mature megakaryocytes to the lungs

Abstract: To determine the locus of platelet production, we sought to determine if sufficient megakaryocytes reach the lungs in a state that could produce platelets. Elutriation was used to isolate megakaryocytes from blood reaching and leaving the lungs of 20 patients undergoing routine cardiac catheterizations. A mean of 5.0 intact megakaryocytes/ml were found in pulmonary artery blood, compared to only 0.5 megakaryocytes/ml, with partial cytoplasmic content, in aortic samples. The megakaryocytes in central venous and aortic samples were all mature. The identity of these cells as megakaryocytes, their maturity and normal morphology were confirmed by standard and immunoelectron microscopy. Cardiac outputs were obtained for each patient at the time of blood sampling, allowing an extrapolation that 40 × 10⁶ intact, mature megakaryocytes were being delivered to the lungs every day in the average patient, compared to only 4.0 × 10⁶ partially spent megakaryocytes exiting the lungs daily. About 98% of megakaryocyte cytoplasm reaching the lungs did not exit as recognizable megakaryocytes or fragments. The number and state of the megakaryocytes apparently filtered in the lungs is consistent with the hypothesis that megakaryocytes may shed platelets within the pulmonary microvasculature, which may be the primary site of platelet production.     

Solitary pulmonary metastasis: an enigma

Lung metastases, which are an expression of the new phase of the underlying neoplastic disorder, have been treated in the recent years by multiple disciplinary approach. When the metastases to the lungs are multiple, it is indicative of extensive tumor burden, and the organ plays an insignificant role in the distribution of the metastases in the different lobes of the lungs. However, when the pulmonary metastases appear after a prolonged disease-free interval it becomes an enigma; when the metastases are solitary, the majority (over 80% in this series) are located in the upper zone of the lungs. This study of 28 patients with solitary lung metastases explores the possible etiology of this clinical observation and proposes that the pattern of perfusion and anatomopathological features of the upper lobes are the main reasons why these lobes are prevalently the sites for solitary lung metastases.     

Conclusive evidence for distinct transporters for 5-hydroxytryptamine and noradrenaline in pulmonary endothelial cells of the rat

The aims of this study were to obtain conclusive evidence about the roles of a 5-hydroxytryptamine [5-HT] transporter and uptake, in the dissipation of 5-HT in the lungs of the rat and to compare the properties of the 5-HT transporter in rat lungs with that in other tissues, including brain and platelets. In the first part of the study, the IC₅₀ values of a range of selective inhibitors and substrates of the 5-HT transporter or uptake₁ were determined for inhibition of uptake of 5-HT or noradrenaline in intact perfused lungs of rats. Monoamine oxidase was inhibited and, in experiments with noradrenaline, catechol-O-methyltransferase was also inhibited. Initial rates of uptake of 5-HT or noradrenaline were measured in lungs perfused with 2 nmol/l ³H-5-HT or ³H-noradrenaline for 2 min, in the absence or presence of at least three concentrations of paroxetine, citalopram, fluoxetine, 7-methyltryptamine, tryptamine, nisoxetine, imipramine, 5-HT, desipramine, (+)-oxaprotiline, cocaine or tyramine. The results showed that pharmacologically distinct transporters are involved in the uptake of 5-HT and noradrenaline in rat lungs, since there was no significant correlation between the IC₅₀ values for inhibition of 5-HT and noradrenaline uptake in the lungs. However, there were significant correlations between the IC₅₀ values for (a) inhibition of 5-HT uptake in rat lungs and of uptake by the 5-HT transporter in rat brain and (b) inhibition of noradrenaline uptake₁ in rat lungs and of uptake, in rat phaeochromocytoma PC-12 cells. The results support the conclusion that 5-HT uptake in rat lungs occurs, at least predominantly, by a 5-HT transporter which is very similar to or the same as that in other tissues, such as the brain, and provide further evidence for transport of noradrenaline by uptake₁.Further experiments were carried out to determine whether there is any transport of 5-HT by uptake₁ or of noradrenaline by the 5-HT transporter in rat lungs. Lungs were perfused with 2 nmol/1 ³H-5-HT or ³H-noradrenaline for 2 min in the absence or presence of 1 mol/l citalopram, desipramine, or citalopram and desipramine. The results showed that there was no evidence of any transport of 5-HT in the lungs by uptake₁ or of noradrenaline by the 5-HT transporter, in that desipramine had no effect on 5-HT uptake (in the absence or presence of citalopram) and citalopram had no effect on noradrenaline uptake (in the absence or presence of desipramine).The final series of experiments was carried out to determine whether, at high concentrations of the amine, there is any interaction of 5-HT with uptake₁ or of noradrenaline with the 5-HT transporter. Noradrenaline, at a concentration of 10 mol/l, did not affect 5-HT uptake in lungs perfused with 2 nmol/l ³H-5-HT for 2 min (uptake₁ inhibited), but 50 mol/l 5-HT inhibited noradrenaline uptake by 56% in lungs perfused with 2 nmol/l ³H-noradrenaline for 2 min (5HT transporter inhibited). These and the above results show that the 5-HT transporter appears to be exclusively responsible for 5-HT uptake in rat lungs, despite the possible interaction of 5-HT at high concentrations with the uptake, transporter in the cells. On the other hand, noradrenaline is transported exclusively by uptake₁ in the lungs, and there is no evidence that it interacts with the 5-HT transporter, even at high concentrations.Preliminary results of this study were presented to the December 1993 meeting of the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists (Paczkowski and Bryan-Lluka 1993).     

Amezinium and debrisoquine are substrates of uptake1 and potent inhibitors of monoamine oxidase in perfused lungs of rats

Previous studies have resulted in the classification of amezinium as a selective inhibitor of neuronal monoamine oxidase (MAO), because it is a much more potent MAO inhibitor in intact tissues, in which it is accumulated in noradrenergic neurones by uptake₁, than in tissue homogenates. In the present study, the effects of amezinium on the deamination of noradrenaline were investigated in intact lungs of rats, since the pulmonary endothelial cells are a site where the catecholamine transporter is non-neuronal uptake₁. In addition, another drug that is both a substrate of uptake₁ and a MAO inhibitor, debrisoquine, was investigated in the study.The first aim of the study was to show whether amezinium and debrisoquine are substrates of uptake₁ in rat lungs. After loading of isolated perfused lungs with ³H-noradrenaline (MAO and catechol-O-methyltransferase (COMT) inhibited), the efflux of ³H-noradrenaline was measured for 30 min. When 1 mol/l amezinium or 15 mol/l debrisoquine was added for the last 15 min of efflux, there was a rapid and marked increase in the fractional rate of loss of ³H-noradrenaline, which was reduced by about 70% when 1 mol/l desipramine was present throughout the efflux period. These results showed that both drugs were substrates for uptake1 in rat lungs. In lungs perfused with 1 nmol/l ³H-noradrenaline (COMT inhibited), 10, 30 and 300 nmol/l amezinium caused 58%, 76% and 74% inhibition of noradrenaline deamination, respectively, and 30, 300 and 3000 nmol/l debrisoquine caused 56%, 89% and 96% inhibition of noradrenaline deamination, respectively. When MAO-B was also inhibited, 10 nmol/l amezinium caused 84% inhibition of the deamination of noradrenaline by MAO-A in the lungs. In contrast, in hearts perfused with 10 nmol/l ³H-noradrenaline under conditions where the amine was accumulated by uptake₂ (COMT, uptake₁ and vesicular transport inhibited), 10 nmol/l amezinium had no effect and 300 nmol/l amezinium caused only 36% inhibition of deamination of noradrenaline.The results when considered with previous reports in the literature show that amezinium is about 1000 times more potent and debrisoquine is about 20 times more potent for MAO inhibition in rat lungs than in tissue homogenates, and the reason for their high potencies in the intact lungs is transport and accumulation of the drugs in the pulmonary endothelial cells by uptake₁. Amezinium is much less potent as a MAO inhibitor in cells with the uptake₂ transporter, such as the myocardial cells of the heart. The results also confirmed previous reports that amezinium is highly selective for MAO-A.Abbreviations COMT catechol-O-methyltransferase - DOMA 3, 4-dihydroxy-mandelic acid - DOPEG 3, 4–'dihydroxyphenylglycol - ECS extracellular space - FRL fractional rate of loss - IC ₅₀ inhibitor concentration that causes 50% inhibition - K _{m uptake} Michaelis or half-saturation constant for uptake - k _{M AO} rate constant for deamination - k _{out NA} rate constant for efflux of noradrenaline - MAO monoamine oxidase - MAO-Aa type A monoamine oxidase - MAO-B type B monoamine oxidase - T/M _NA tissue to medium ratio of noradrenaline - U-0521 3, 4-dihydroxy-2-methylpropiophenone - V _max maximal rate - v _st–st steady-state rate of metabolite formation Preliminary results of this study were presented to the 1993 Meeting of the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists (Bryan-Lluka 1993).     

A retrospective database analysis to evaluate the potential of ex vivo lung perfusion to recruit declined lung donors

Ex vivo lung perfusion (EVLP) is currently used for both standard and extended‐criteria donor (ECD) lungs. To enlarge the donor pool, we might have to extend the threshold for ECD donation. The purpose of this study was to estimate how many additional ECD lungs could be recruited by EVLP. We reviewed all multi‐organ donors (MODs) from our collaborative donor hospitals (January 2010–June 2015). All unused lung donors were categorized using registered donor data and evaluated by two independent investigators to identify which lungs could be transplanted after EVLP. 584 MODs were registered at our transplant center. 268 (45.9%) were declined as lung donor at the moment of registration, and 316 (54.1%) were considered as a donor for lung transplantation. In the latter, lungs from 220 (37.7%) donors were transplanted and 96 donors (16.4%) were not. We identified 78 of 364 declined donors (21.4%) whose lungs could potentially become transplantable after EVLP. With this retrospective database analysis of unused lung donors, we identified a large potential for EVLP to further increase the donor pool in transplant centers where the majority of donor lungs are already extended.     

Solute Absorption from the Airways of the Isolated Rat Lung. III. Absorption of Several Peptidase-Resistant,Synthetic Polypeptides: Poly-(2-Hydroxyethyl)-Aspartamides

A series of samples of the synthetic polypeptide poly-,-[N(2-hydroxyethyl)-DL-aspartamide] (PHEA), containing covalently bound fluorophore, ethylcarbonyl-6-aminofluorescein, and exhibiting different molecular weight distributions with weight average molecular weights ranging from approximately 4 to 43 kD, was prepared and characterized. Aqueous solutions of the polymers were administered to the airways of isolated perfused rat lung preparations, and transfer to the perfusate was measured. Polymers administered directly to the perfusate were not degraded during the experiment. Polymer transfer rates were dependent upon starting molecular weight distribution, larger molecules being absorbed more slowly. In the case of a polymer with a median molecular weight of 7.2 kD, the absorbed species appeared to be smaller molecules than those which were originally administered. This was not the case for a 3.98-kD polymer; absorbed material had a gel permeation chromatography elution volume equivalent to that of the administered material. Absorption for the 3.98-kD polymer was found to be dose dependent. Approximately 70% absorption of a 0.2-mg dose occurred in 100 min. Much larger polymers (up to 11.65 kD) were also absorbed at finite rates. Results are discussed in the context of macromolecular delivery to the systemic circulation via the lung.