Early-life co-administration of cockroach allergen and endotoxin augments pulmonary and systemic responses.

BACKGROUND: Environmental exposures to cockroach allergen and endotoxin are recognized epidemiological risk factors for the early development of allergies and asthma in children. Because of this, it is important to examine the role of early-life concurrent inhalation exposures to cockroach allergen and endotoxin in the pathogenesis of allergic airways disease. OBJECTIVE: We examined the effects of repeated concomitant endotoxin and cockroach allergen inhalation on the pulmonary and systemic immune responses of newborn and juvenile mice. METHODS: C3H/HeBFeJ mice were exposed to inhaled endotoxin and cockroach allergen via intranasal instillation from day 2 to 21 after birth, and systemic and pulmonary responses were examined in serum, bronchoalveolar lavage fluid, and lung tissue. RESULTS: Cockroach allergen exposures induced pulmonary eosinophilic inflammation, total and allergen-specific IgE, IgG(1), and IgG(2a) production, and alveolar remodelling. Co-exposures with endotoxin and cockroach allergen significantly increased serum IgE and IgG(1), lung inflammation, and alveolar wall thickness, and decreased airspace volume density. Importantly, compared with exposures with individual substances, the responses to co-exposures were more than additive. CONCLUSIONS: Repeated inhalation exposures of neonatal and juvenile mice to endotoxin and cockroach allergen increased the pulmonary inflammatory and systemic immune responses in a synergistic manner and enhanced alveolar remodelling in the developing lung. These data underscore the importance of evaluating the effect of multiple, concurrent environmental exposures, and of using an experimental model that incorporates clinically relevant timing and route of exposures.

Lesions of the rat nucleus basalis magnocellularis disrupt appetitive-to-aversive transfer learning.

Rats with selective lesions of the nucleus basalis magnocellularis (NBM) and sham-lesion control animals were tested in an operant appetitive-to-aversive transfer task. We hypothesized that NBM lesions would not affect performance in the appetitive phase, but that performance would be impaired during subsequent transfer to the aversive phase of the task. Additional groups of NBM lesion and control rats were tested in the avoidance condition only, where we hypothesized that NBM lesions would not disrupt performance. These hypotheses were based on the argument that the NBM is not necessary for simple association learning that does not tax attention. Both the appetitive phase of the transfer task and the avoidance only task depend only on simple associative learning and are argued not to tax attention. Consequently, performance in these tasks was predicted to be spared following NBM lesions. Complex, attention-demanding associative learning, however, is argued to depend on the NBM. Performance in the aversive phase of the transfer task is both attentionally demanding and associatively more complex than in either the appetitive or aversive tasks alone; thus, avoidance performance in the NBM lesion group was predicted to be impaired following transfer from prior appetitive conditioning. Results supported our hypotheses, with the NBM lesion group acquiring the appetitive response normally, but showing impaired performance following transfer to the aversive conditioning phase of the transfer task. Impairments were not attributable to disrupted avoidance learning per se, as avoidance behavior was normal in the NBM lesion group tested in the avoidance condition only.

Endotoxin responsiveness and subchronic grain dust-induced airway disease.

Endotoxin is one of the principal components of grain dust that causes acute reversible airflow obstruction and airway inflammation. To determine whether endotoxin responsiveness influences the development of chronic grain dust-induced airway disease, physiological and airway inflammation remodeling parameters were evaluated after an 8-wk exposure to corn dust extract (CDE) and again after a 4-wk recovery period in a strain of mice sensitive to (C3H/HeBFeJ) and one resistant to (C3H/HeJ) endotoxin. After the CDE exposure, both strains of mice had equal airway hyperreactivity to a methacholine challenge; however, airway hyperreactivity persisted only in the C3H/HeBFeJ mice after the recovery period. Only the C3H/HeBFeJ mice showed significant inflammation of the lower airway after the 8-wk exposure to CDE. After the recovery period, this inflammatory response completely resolved. Lung stereological measurements indicate that an 8-wk exposure to CDE resulted in persistent expansion of the airway submucosal cross-sectional area only in the C3H/HeBFeJ mice. Collagen type III and an influx of cells into the subepithelial area participated in the expansion of the submucosa. Our findings demonstrate that subchronic inhalation of grain dust extract results in the development of chronic airway disease only in mice sensitive to endotoxin but not in mice that are genetically hyporesponsive to endotoxin, suggesting that endotoxin is important in the development of chronic airway disease.

Effects of lisofylline on hyperoxia-induced lung injury.

Lisofylline [1-(5R-hydroxyhexyl)-3,7-dimethylxanthine] decreases lipid peroxidation in vitro and in vivo suppresses proinflammatory cytokine expression in models of lung injury due to sepsis, blood loss, and oxidative damage. In the present experiments, we used a murine hyperoxia model to examine the effects of lisofylline on the activation of nuclear transcriptional regulatory factors [nuclear factor-kappaB and cAMP response element binding protein (CREB)], the expression of proinflammatory cytokines in the lungs, and the circulating levels of oxidized free fatty acids as well as on hyperoxia-induced lung injury and mortality. Treatment with lisofylline inhibited hyperoxia-associated increases in tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 in the lungs as well as decreased the levels of hyperoxia-induced serum-oxidized free fatty acids. Although hyperoxic exposure produced activation of both nuclear factor-kappaB and CREB in lung cell populations, only CREB activation was reduced in the mice treated with lisofylline. Lisofylline diminished hyperoxia-associated increases in lung wet-to-dry weight ratios and improved survival in animals exposed to hyperoxia. These results suggest that lisofylline ameliorates hyperoxia-induced lung injury and mortality through inhibiting CREB activation, membrane oxidation, and proinflammatory cytokine expression in the lungs.

Spasticity. Mechanisms and nursing care.

Spasticity is a motor dysfunction affecting persons with an UMN injury in varying ways. Nurses can identify spasticity in their patients by the presence of hyperactive DTRs and hypertonicity (increased muscle tone). Other characteristics often present with spasticity are clonus and spasms. Spasticity interfering with recreation, work, or basic activities of daily living may be decreased through the use of a variety of nursing interventions. Some of these interventions are more advantageous for spasticity caused by brain injury, whereas others are more helpful for spasticity caused by the spinal cord injury. Interventions research has begun; however, more research needs to be done to identify the most effective nursing measures to decrease spasticity.

Immunochemical probing of the structure and cofactor of NADH dehydrogenase from Paracoccus denitrificans.

Monospecific antibody to the respiratory NADH dehydrogenase from Paracoccus denitrificans was prepared by using as antigen specific immunoprecipitates containing NADH dehydrogenase which were excised from crossed-immunoelectrophoresis plates. The latter were run with selectively solubilized plasma membranes and antibodies against plasma membranes. The antibody immunoprecipitated NADH dehydrogenase from P. denitrificans membranes biosynthetically labelled with 14C and solubilized with a wide range of detergents. All immunoprecipitates contained the two subunits of Mr 48,000 and 25,000, in an approximate 1:1 stoichiometry, that had previously been assigned to NADH dehydrogenase. A polypeptide of Mr 46,000 in P. denitrificans membranes, previously shown to cross-react with a subunit-specific antibody to mitochondrial NADH dehydrogenase (complex I), was not detected in any immunoprecipitate. Under some conditions a third polypeptide, of Mr 31,000, was also detected, but in variable and non-stoichiometric amounts relative to the two other subunits. It was concluded that this polypeptide was incorporated into the immunoprecipitates as an artefact and that the polypeptides of Mr 48,000 and 25,000 are the sole polypeptides firmly identified in the NADH dehydrogenase. Flavoproteins were specifically radiolabelled by growth of P. denitrificans in the presence of [14C]riboflavin. Crossed immunoelectrophoresis of membranes from such cells showed that succinate dehydrogenase contained flavin, but that there was no detectable flavin in NADH dehydrogenase under these conditions. Analysis of excised immunoprecipitates of succinate dehydrogenase showed that flavin was covalently bound to a polypeptide of Mr 56,000. Flavin was retained by NADH dehydrogenase under mild conditions of detergent solubilization. Subsequent immunoprecipitation, followed by analysis of the acid-extracted flavin, established that FMN is a cofactor, in common with mitochondrial NADH-ubiquinone oxidoreductase (complex I).

The effect of three species of mites upon fungal growth on wheat.

Every week, for 20 weeks, the growth of naturally occurring grain storage fungi on wheat infested with the three commonest British grain storage mites, Acarus siro, Glycyphagus destructor and Tyrophagus longior, was compared with that on uninfested wheat. The number of colonies of the Aspergillus glaucus group per gram were always less on grain infested with mites than on uninfested grain. Penicillium spp. were also less numerous on grain which was infested with A. siro but did not appear to be affected by the other mites. In contrast, two fungi which are pathogenic to mites, Aspergillus restrictus and Wallemia sebi, were more abundant in the presence of certain mites. The former was associated with G. destructor, the latter with G. destructor and A. siro. The three species of mites either feed on the A. glaucus group and Penicillium spp., or inhibit them by an unknown secretion. Pathogenic fungi are probably avoided. Mites are therefore an important variable in studies on fungal growth during grain drying and storage.

Structural relationships between the NADH dehydrogenases of Paracoccus denitrificans and bovine heart mitochondria as revealed by immunological cross-reactivities.

An antibody raised against two subunits (Mr 48 000 and 25 000) of NADH dehydrogenase from Paracoccus denitrificans cross-reacts with one of more than 20 polypeptides that form the bovine heart mitochondrial NADH dehydrogenase. The cross-reacting subunit has Mr 51 000 and is believed to be the NADH-binding subunit of the enzyme. Antibodies raised against certain subunits of the bovine heart NADH dehydrogenase were tested for cross-reactivity with P. denitrificans cytoplasmic membranes. Of those tested, only one, an antibody specific for the 49 kDa subunit of mitochondrial NADH dehydrogenase, cross-reacted with the bacterial membranes. It recognised a polypeptide of approximate Mr 46 000. This is an indication for a previously undetected third subunit of NADH dehydrogenase from P. denitrificans. The immunological cross-reactions indicate that the NADH dehydrogenases from P. denitrificans and bovine heart mitochondria are related structurally.

Immunochemical identification of a two-subunit NADH-ubiquinone oxidoreductase from Paracoccus denitrificans.

Analysis by crossed-immunoelectrophoresis of Paracoccus denitrificans membrane vesicles has shown that only one antigen stains for NADH dehydrogenase activity. This activity could be partially purified by a combination of gel filtration and ion-exchange chromatography of membrane vesicles that had been solubilised in the non-ionic detergent Nonidet P-40. From the limited number of precipitates observed after crossed immunoelectrophoresis of this partially purified preparation of NADH dehydrogenase it was possible to excise specifically part of the precipitate that stained for NADH dehydrogenase. Excised precipitates containing NADH dehydrogenase that had been radiolabelled by growth of cells in the presence of [35S]SO2-(4) allowed the polypeptide composition of the enzyme to be determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate followed by fluorography. Two subunits were identified with estimated relative molecular masses of 48000 and 25000. Subunits of similar molecular weight are found in the flavoprotein fragment of the NADH dehydrogenase of the mammalian mitochondrial respiratory chain. The latter has general similarities with the respiratory chain in the plasma membrane of P. denitrificans.