No effect of montelukast on asthma-like symptoms in elite ice hockey players.

BACKGROUND: Controlled clinical trials on the effects of leukotriene antagonists on asthma-like symptoms, bronchial hyperresponsiveness and airway inflammation have not been performed in elite athletes. METHODS: In 2001, we examined 88 of 102 (86%) players from three junior, national league ice hockey teams in Helsinki. Athletes were included in the intervention if they reported at least two exercise-induced bronchial symptoms (wheeze, cough, shortness of breath) weekly during the previous month on a previously validated respiratory-symptom questionnaire. Sixteen male ice hockey players fulfilled the study criteria. A double-blind, randomized, cross-over, placebo-controlled study included 4-week active treatment (10 mg oral montelukast, bedtime), 1-week washout period, and 4-week placebo treatment. Before entering the study, all patients were clinically examined, skin prick tested, filled in a respiratory symptom questionnaire, performed a spirometry and a histamine challenge test, and gave induced sputum samples. Exhaled NO was measured. These measures were repeated after both treatment periods. During the treatment the athletes kept daily diary on lower respiratory tract symptoms on a scale from 0 (no symptoms) to 10 (most severe symptoms), morning peak expiratory flow (PEF), training amount, and use of study medication. Primary end-point was daily lower respiratory tract symptom score. RESULTS: Montelukast had no effect on daily lower respiratory symptom scores, spirometry parameters [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, PEF], bronchial hyperresponsiveness, sputum eosinophil or neutrophil cell counts, exhaled NO measurements, or morning PEF. Nine subjects were atopic in skin prick test, but their results did not differ from the nonatopic subjects. CONCLUSION: A leukotriene antagonist, montelukast, was of no benefit in the treatment of asthma-like symptoms, increased bronchial hyperresponsiveness or a mixed type of eosinophilic and neutrophilic airway inflammation in highly-trained ice hockey players.

Airway inflammation, bronchial hyperresponsiveness and asthma in elite ice hockey players.

There is little information of lower respiratory symptoms, bronchial hyperresponsiveness and airway inflammation in elite ice hockey players. A total of 88 highly trained ice hockey players and 47 control subjects were studied. All the subjects were subjected to skin-prick tests, resting spirometry examinations and histamine-challenge tests. Adequate induced sputum samples were obtained from 68 of the ice hockey players and from 18 symptom-free control subjects on a separate day. Bronchial hyperresponsiveness in a histamine-challenge test was found in 21 (24%) of the athletes and in five (11%) of the controls. Current asthma (current asthmatic symptoms and increased bronchial responsiveness) was observed in 13 (15%) of the athletes and in one (2%) of the control subjects. Total asthma (current asthma or previously physician-diagnosed asthma) occurred in 19 (22%) of the athletes and in two (4%) of the controls. Atopy, according to skin-prick tests, was observed in 51 (58%) of the athletes and 17 (36%) of the control subjects. The differential cell counts of eosinophils (2.6 versus 0.2%) and neutrophils (80.9 versus 29.9%) in the sputum samples of the ice hockey players were significantly higher than in those of the control subjects. Asthma is common in elite ice hockey players and they show signs of a mixed type of neutrophilic and eosinophilic airway inflammation. Inhalation of cold air associated with exposure to indoor pollutants during intensive training is a possible causative factor.

Exercise-induced changes in pulmonary function of healthy, elite long-distance runners in cold air and pollen season exercise challenge tests.

Exercise-induced changes in postexercise pulmonary function have not been studied in healthy elite athletes in normal training conditions. Twelve healthy elite runners volunteered. They showed normal resting spirometry and bronchial responsiveness to histamine, and were non-atopic. They performed free running exercise challenge tests (ECT) at subzero temperature and immediately after highest birch pollen season. The mean maximal postexercise changes in FEV(1), PEF, FVC, and FEV(1)/FVC did not differ between the cold air and pollen season ECTs. Compared with pre-exercise values, FEV(1)increased significantly at 10 min (p = 0.028) and 20 min (p = 0.033) postexercise in the cold air ECT, as well as at 10 min (p = 0.024) and 20 min (p = 0.010) postexercise in the pollen season ECT. The mean (SEM) maximal postexercise change in FEV(1) was mostly small + 2.6 (0.6)% in the winter and + 2.7 (0.9)% in the pollen season. In contrast, significant decreases in PEF, compared with baseline, were found at 10 min (p = 0.071) and 20 min (p = 0.0029) postexercise in the cold air ECT, as well as at 10 min (p = 0.060) and 20 min (p = 0.010) postexercise in the pollen season ECT (p = 0.0076). The mean (SEM) maximal postexercise fall in PEF was 5.9 (1.0)% in the winter and 6.0 (1.8)% in the pollen season. Heavy exercise challenge tests in extreme conditions increased FEV(1) post-exercise, while PEF decreased as compared with pre-exercise values. Thus, even small postexercise falls in FEV(1) may be considered as deviate exercise responses in elite athletes.

Nitric oxide synthase immunoreactivity in the rat hippocampus after status epilepticus induced by perforant pathway stimulation.

Nitric oxide has recently been implicated in mediation of neuronal excitotoxicity and damage. This study aimed at elucidating the changes in the expression of neuronal isoform of nitric oxide synthase (nNOS) in the hippocampus after status epilepticus induced by perforant pathway stimulation. nNOS-immunoreactivity (nNOS-ir) and neuronal damage, assessed by silver staining, were evaluated separately in different hippocampal subfields 2 weeks after induction of status epilepticus. Perforant pathway stimulation resulted in an increase in the number of nNOS-immunoreactive neurons in the stratum radiatum of the CA1 and CA3 subfields of the hippocampus proper, and the hilus of the dentate gyrus. The morphology and distribution of the nNOS-ir neurons resembled that of interneurons. No correlation of the number of nNOS-ir neurons to the neuronal damage score was observed. Our results suggest that status epilepticus provokes a de novo expression of nNOS protein, and the nNOS expressing neurons may be selectively resistant to epileptic brain injury.

Age-related augmentation of the dehydration-induced increase in the supraoptic nitric oxide synthase activity in rats.

Hypothalamic supraoptic nucleus (SON) neurons express nitric oxide synthase (NOS) in an activity-dependent manner. In the present study, the effect of aging on the NOS expression of the SON neurons, as detected by nicotinamide adenine dinucleotide phosphate-diaphorase activity, was studied under normal conditions and under dehydration stress induced by salt loading. In the control rats, the number of stained neurons did not differ between the two age groups. Dehydration resulted in an increase in both the number of staining neurons and in the staining intensity in both 2- and 14-16-month-old rats. Furthermore, dehydration-induced NOS expression was significantly higher in the older animals. The results suggest that the response to dehydration, as indicated by increased NOS activity in the supraoptic nucleus, is enhanced in the aging rat.

Colchicine differentially induces the expressions of nitric oxide synthases in central and peripheral catecholaminergic neurons.

This study was aimed at elucidating differences in nerve injury induced expression of nitric oxide synthases (NOS) between the peripheral and central catecholaminergic neurons. Colchicine was used to disrupt chemically the neuronal cytoskeletal integrity. A marked increase in the expression of neuronal NOS-IR and NADPH-diaphorase activity, a marker of neuronal NOS (nNOS), was seen in distinct populations of post-ganglionic sympathetic neurons of the superior cervical ganglion after intraganglionic colchicine injection. Similarly, immunoreactivity for the inducible form of NOS (iNOS) was induced in some sympathetic neuron somata. However, this immunoreactivity did not coincide with nNOS-IR. In contrast to the sympathetic neurons, hypothalamic arcuate and periventricular dopaminergic neurons did not show NOS-IR or NADPH-DA either in intact animals or in animals treated with an intracerebroventricular injection of colchicine. Immunoreactivity for the inducible form of NOS revealed no neuronal staining in the hypothalamic neurons in either group, while a large number of glia-resembling cells around the third ventricle showed slight expression of iNOS-IR. The present results show that expression of both neuronal and inducible forms of NOS may be induced by colchicine in some catecholaminergic neurons. It is suggested that these inductions are specific to certain catecholaminergic neuronal systems, like the sympathetic neurons, rather than a general property of catecholaminergic neurons.

Pancreatic carcinomas deposit laminin-5, preferably adhere to laminin-5, and migrate on the newly deposited basement membrane.

We studied the adhesion mechanism of pancreatic carcinoma using in vitro adhesion and migration assays of stable cell lines and tumors grown from these cell lines in nude mice. We also compared the results with the expression profiles of laminins and their receptors in pancreatic carcinomas to evaluate the relevance of these mechanisms in vivo. All of the cell lines preferably adhered to laminin-5, irrespective of their capability to synthesize laminin-5. Cell migration was studied in the presence of hepatocyte growth factor, as it increased the speed of migration manyfold. Herbimycin A treatment and antibodies against the beta 1 and alpha 3 integrin subunits and laminin alpha 3 chain almost entirely blocked cell migration of the BxPC-3 cell line, whereas migration was nearly unaffected by RGD peptide and only moderately inhibited by antibody against the alpha 6 integrin subunit. Indirect immunofluorescence microscopy of wounded BxPC-3 cells suggested a rapid endocytosis of alpha 3 integrin subunit in the cells at the margin of the wound and a rapid, polarized rearrangement of the alpha 6 beta 4 integrin. Especially HGF-treated cultures showed a prominent cytoplasmic reaction for laminin-5 at the margin of the wound. Xenografted cells formed tumors that produced and deposited the same laminin chains as the in vitro cultures. Frozen sections of human pancreatic carcinomas showed reactivity for laminin chains suggestive for expression of laminin-1 and laminin-5. Both xenografted tumors and human pancreatic carcinomas also showed stromal reactivity for laminin-5. Electron microscopy of the human tumors suggested that this was due to an abundant reduplication the basement-membrane-like material around the nests of malignant cells. Our results suggest that pancreatic carcinomas synthesize and deposit laminin-5 in the basement membrane in an abnormal manner. Invading cells adhere to this newly produced basement membrane and migrate on it by using the alpha 3 beta 1 integrin receptor recognizing laminin-5.

Expression of nitric oxide synthase in hypothalamic nuclei following axonal injury or colchicine treatment.

Nitric oxide (NO) has recently gained much attention due to its apparently double-edged role in neuronal injury. This study was aimed at elucidating neuronal nitric oxide synthase (nNOS) expression in the brain after two types of injury, namely axonal transection and colchicine treatment. The neurosecretory hypothalamo-pituitary pathway served as a model for the reaction of central neurons to these two types of injury. Axonal transection, i.e., pituitary stalk section, resulted in a qualitative increase in NOS content in the supraoptic and paraventricular nuclei. In these nuclei, there was also an increase in the number of NOS-expressing neurons after the operation. Surprisingly, in the periventricular nucleus, a strong decrease in the number of NOS-positive magnocellular neurons was observed in the anterior part of the nucleus. Intracerebroventricular injection of colchicine resulted in an increase in the cell count in the paraventricular nucleus, while the other nuclei remained unchanged. Our results suggest that axonal injury results in an increase in nNOS expression in the major neurosecretory nuclei, while the periventricular nucleus shows the opposite reaction. Colchicine treatment has an effect similar to that of axotomy in the major neurosecretory nuclei, suggesting that an increase in NOS expression may be induced by interrupted axonal transport. In the periventricular nucleus, the decrease in the number of NOS-containing neurons suggests differences among hypothalamic NOS-containing neuron groups in response to neuronal injury.

Nitric oxide synthase in the autonomic and sensory ganglia innervating the submandibular salivary gland.

This article reviews the neuroanatomical studies on the distribution of nitric oxide synthase (NOS) in neurons and nerve fibers innervating the submandibular gland. Specificity of NADPH-diaphorase activity as a histochemical marker of neuronal NOS is discussed in light of corresponding NOS immunoreactivity. Anatomical data suggest that nitric oxide may affect neural regulation of the submandibular gland through both sympathetic, parasympathetic and sensory divisions of the autonomic nervous system. NOS-containing nerve terminals in the gland parenchyme are mainly vascular and either parasympathetic and/or sensory in nature, while sympathetic terminals lack NOS. Most postganglionic parasympathetic neurons are intensely NOS-immunoreactive. Some of the preganglionic parasympathetic neurons show vague reactivity, while their terminals in the submandibular ganglia stain heavily. The postganglionic sympathetic neurons normally show only barely visible reactivity, while manipulations interrupting axonal continuity increase neuronal NOS content. A subpopulation of the preganglionic sympathetic neurons and their terminals are intensely reactive. The observations summarized here suggest that nitric oxide participates in the control of blood flow through the gland, while direct effect on secretion is unlikely.

Axonal transport of nitric oxide synthase in autonomic nerves.

By using mechanical nerve ligation or nerve pinch technique, we provide evidence that nitric oxide synthase (NOS) is transported in the preganglionic sympathetic axons, while postganglionic axons lack NOS transport. This finding corroborates the preganglionic sympathetic terminal as the site of NO synthesis, which is known to affect ganglionic transmission. Both vasoactive intestinal polypeptide (VIP) and substance P (SP) containing neurons of the nodose ganglion transport NOS in their axons. These results therefore suggest that NOergic innervation of autonomically innervated tissues is of parasympathetic and/or sensory, rather than sympathetic, origin.