The type 2 corticotrophin-releasing hormone receptor mediates orexin A-induced luteinising hormone suppression in ovariectomised rats

Orexins are thought to be regulatory factors of the arousal and sleep patterns. They also affect immune, feeding, autonomic and neuroendocrine systems. We have previously shown that intracerebroventricular (i.c.v.) injection of orexin decreases pulsatile luteinising hormone (LH) secretion in ovariectomised (OVX) rats. However, the details of this mechanism have not been fully examined. Intracerebroventricular injection of orexin A also stimulates corticotrophin-releasing hormone (CRH) systems, which have been implicated in the stress-induced suppression of reproductive function. In the present study, we investigated the role of CRH systems in orexin-induced LH suppression. OVX rats were implanted with i.c.v. and intravenous (i.v.) cannulae. After i.c.v. injection of orexin and/or CRH receptor antagonists, blood samples were collected through the i.v. cannula at 6-min intervals for 120 min for LH measurement. Intracerebroventricular injection of orexin A or B (3 nmol/2.5 microl) suppressed pulsatile LH secretion. Coadministration of orexin A and alpha-helical corticotrophic-releasing factor (CRF), a nonselective CRH receptor antagonist (13 nmol/2.5 microl), or astressin(2)B, a selective type2 (CRH-R2) CRH receptor antagonist (28 nmol/2.5 microl), partly restored pulsatile LH secretion. Orexin B-induced LH suppression was not restored by alpha-helical CRF. In addition, i.c.v. injection of orexin A increased CRH and urocortin II (UcnII), but not Ucn mRNA levels, in the hypothalamus. These findings suggest that CRH-R2 mediates orexin A-induced LH suppression and it is possible that CRH and UcnII in the hypothalamus are involved in this pathway.

Relationship of airway wall thickening to an imbalance between matrix metalloproteinase-9 and its inhibitor in asthma

BACKGROUND

The balance between matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) may be critical in extracellular matrix remodelling, a characteristic of asthmatic airways. An excess of TIMP-1 over MMP-9 has been associated with chronic airflow obstruction but the mechanisms underlying this association remain unknown. Recent computed tomographic (CT) studies indicate that airway wall thickening is associated with chronic airflow obstruction.

METHODS

Sputum levels of MMP-9, TIMP-1, and their molar ratio were examined in 26 patients with stable asthma and their relationship with pulmonary function and airway wall thickness, assessed by a validated CT technique which measured wall area corrected by body surface area (WA/BSA), the ratio of WA to outer wall area (WA%), and the absolute wall thickness corrected by radicalBSA of a segmental bronchus (T/ radicalBSA), was examined.

RESULTS

Sputum MMP-9 levels were inversely correlated with WA% and TIMP-1 levels were positively correlated with WA/BSA and T/ radicalBSA. The MMP-9/TIMP-1 molar ratio was inversely correlated with WA% and T/ radicalBSA and positively correlated with post-bronchodilator values of mid-forced expiratory flow and maximum expiratory flow at the quartile of lung volume.

CONCLUSION

Excess TIMP-1 may have a pathogenetic role in airway wall thickening in asthmatic patients which may result in chronic airflow obstruction.

Serum eosinophil cationic protein levels measured during exacerbation of asthma: characteristics of patients with low titres

BACKGROUND

Serum eosinophil cationic protein (ECP) levels reflect ongoing eosinophilic airway inflammation and are used as a marker for asthma activity. ECP levels, however, may not be elevated in some asthmatic patients, even when they are symptomatic.

OBJECTIVE

To clarify the characteristics of patients with 'low' ECP titres despite asthma exacerbation.

METHODS

Serum ECP levels were measured in 113 asthmatic patients during exacerbation. Patients were divided into two groups according to ECP titre: a high ECP group (H; ECP > or = 16.0 microg/L) and a low ECP group (L; ECP <16.0 microg/L). Twenty-two patients who had recently received systemic steroids were excluded and the clinical features of the remaining patients in H (n = 54) and L (n = 37 were compared.

RESULTS

Gender, atopic or smoking status, disease severity, inhaled steroid or theophylline usage, peak expiratory flow (% personal best) and forced expiratory volume in 1 s (FEV1) (% predicted) did not significantly differ between the two groups. Patients in L were significantly older and had longer disease duration and lower serum IgE levels than those in H. Multivariate analysis combining age, disease duration and IgE levels showed that age and disease duration were independently associated with ECP level. Airway wall thickness, assessed in a subset of patients using computed tomography, was significantly larger in L.

CONCLUSION

Serum ECP levels in asthmatic patients may not be elevated during exacerbation and thus may not be a useful marker in patients who are older, have longer disease duration or possibly have thicker airway walls. Mechanisms other than eosinophilic inflammation, such as airway remodelling, may be involved in asthma exacerbation in these patients.

Identification and characterization of SEB, a novel protein that binds to the acute undifferentiated leukemia-associated protein SET

SET, the translocation breakpoint-encoded protein in acute undifferentiated leukemia (AUL), is a 39-kDa nuclear phosphoprotein and has an inhibitory activity for protein phosphatase 2A (PP2A). SET is fused to a putative oncoprotein, CAN/NUP214, in AUL and is thought to play a key role in leukemogenesis by its nuclear localization, protein-protein interactions and PP2A inhibitory activity. Here, we describe the isolation and characterization of a novel cDNA encoding a protein with 1542 amino-acid residues that specifically interacts in a yeast two-hybrid system as well as in human cells with SET. This new protein, which we name SEB (SET-binding protein), is identified as a 170-kDa protein by immunoprecipitation with a specific antibody and is localized predominantly in the nucleus. SEB1238--1434 is determined as a SET-binding region that specifically binds to SET182--223. SEB also has an oncoprotein Ski homologous region (amino acids 654--858), six PEST sequences and three sequential PPLPPPPP repeats at the C-terminus. SEB mRNA is expressed ubiquitously in all human adult tissues and cells examined. The SEB gene locus is assigned to the chromosome 18q21.1 that contains candidate tumor suppressor genes associated with deletions in cancer and leukemia. Although the function of SEB is not known, we propose that SEB plays a key role in the mechanism of SET-related leukemogenesis and tumorigenesis, perhaps by suppressing SET function or by regulating the transforming activity of Ski in the nucleus.

Airway wall thickness in asthma assessed by computed tomography. Relation to clinical indices

Postmortem studies have shown that airway wall thickening is present in asthmatic patients and may play a pathophysiologic role. We investigated the presence and characteristics of airway wall thickening in patients with asthma, using helical computed tomography. Eighty-one asthmatic patients and 28 healthy control subjects were studied cross-sectionally. Airway wall thickness was assessed by a validated method on the basis of wall area (WA), WA corrected by body surface area (WA/BSA), and WA%, defined as (WA/total area) x 100 at the apical bronchus of the right upper lobe. Airway luminal area (Ai) and Ai/BSA were also examined. Asthma duration and severity, pulmonary function, and serum eosinophil cationic protein levels were evaluated. Intraobserver and interobserver reproducibility of WA, WA%, and Ai measurements were good. As compared with control, WA, WA/BSA, and WA% were significantly increased in patients with mild (n = 13), moderate (39), and severe persistent (22) asthma but not in patients with intermittent asthma (7). Comparison of the four asthmatic subgroups demonstrated thicker airways in more severe disease, but no difference in Ai or Ai/BSA. When all asthmatic patients were analyzed together, WA and WA/BSA correlated with the duration, although weakly, and severity of asthma. WA and WA/BSA negatively correlated with FEV(1) (percentage of predicted), FEV(1)/FVC (%), and FEF(25-75%) (percentage of predicted), whereas WA% negatively correlated with only FEV(1). We conclude that airway wall thickening occurs in patients with asthma and is not limited to those with severe disease. The degree of airway wall thickening may relate to the duration and severity of disease and the degree of airflow obstruction.

Airway remodelling in cough-variant asthma

Subepithelial-layer thickening, a pathological feature of airway remodelling, is present in cough-variant asthma. In bronchial biopsy samples we found mean subepithelial-layer thickness was 7.1 (SE 0.4) microm in patients with cough-variant asthma, 8.6 (0.4) microm in patients with classic asthma with wheezing, and 5.0 (0.2) microm in healthy controls. Thickness was significantly higher in patients with asthma than in controls, and was significantly greater in those with classic asthma than in those with cough-variant asthma. Early anti-inflammatory treatment might, therefore, be beneficial in cough-variant asthma, as recommended in classic asthma.

[A study on cases diagnosed as pulmonary tuberculosis after admission to the general hospital lacking tuberculosis ward]

We analyzed retrospectively the clinical data of 12 patients diagnosed as pulmonary tuberculosis after admission to the National Himeji Hospital during the past 5 years. Ten out of 12 patients were male and were of elder age-groups (mean age: 65.5 years, range: 32-76 years). Seven patients at first visited the department of respiratory medicine, and the remaining three patients were admitted without consulting the department of respiratory medicine before admission. Only patient had a history of pulmonary tuberculosis. Two patients were suspected of pulmonary tuberculosis on admission. Tubercle bacilli were positive sputum smear in 6 patients, sputum culture in 1, smear of bronchial washing in 4, and smear of BALF in 1. It took 12.7 days on the average from the admission to make a final diagnosis as pulmonary tuberculosis patients into a general hospital lacking TB ward were as follows: (1) As pulmonary TB was not suspected, Chest X-ray and sputum examination were not performed. (2) The admission was done due to another disease and respiratory symptoms were scarce. (3) Tuberculosis lesions on chest X-ray were harbored by pleural effusions and diffuse shadows. (4) Though pulmonary tuberculosis was suspected, a patient was admitted because of general prostration as sputum smear was negative. After admission, however, repeated sputum culture revealed positive results. (5) Pulmonary tuberculosis developed after the admission.