Different types of relationship between beta-adrenergic relaxation and activation of cyclic AMP-dependent protein kinase in canine saphenous and portal veins

We examined the relationships between the relaxation mediated by beta-adrenoceptor and either the associated cyclic AMP production or the activation of cyclic AMP-dependent protein kinase (A-PK) in canine saphenous and portal veins. In the saphenous vein constricted with methoxamine, isoproterenol caused concentration-dependent relaxation (maximum relaxation 92.7%), and concomitant increases in cyclic AMP and A-PK activity ratio (from 52.8 to 73.5%). The portal vein was only slightly relaxed by isoproterenol (14.7% in the longitudinal strips) after constriction with methoxamine, while cyclic AMP and A-PK activation increased significantly. Isoproterenol markedly activated A-PK of the portal vein after KCl constriction (from 52.6 to 74.6%) but the maximum relaxation was only slight (13.3%). The portal vein also showed a smaller relaxation response to either forskolin or dibutyryl cyclic AMP than the saphenous vein. These results indicated that the relationship between the relaxation response to isoproterenol and either cyclic AMP production or A-PK activation was different in the saphenous and portal veins.     

Suppressor T-lymphocyte dysfunction in MCNS: role of the H2 histamine receptor-bearing suppressor T lymphocytes

To evaluate the number and function of suppressor T cells in children with minimal change nephrotic syndrome (MCNS), we performed an inhibition test of rosette formation and measured leukocyte procoagulant activity. The number of histamine H2 receptor-bearing T lymphocytes (histamine H2 R+ lymphocytes) was markedly decreased at the onset of MCNS but gradually increased and was normalized following steroid therapy. The production of leukocyte procoagulant activity by normal T lymphocytes was abolished by incubation with patient's lymphocytes. However, pretreatment of the normal T lymphocytes with cimetidine markedly decreased the suppression. The results suggest an abnormality in the histamine H2 receptors on the patient's suppressor T lymphocytes.     

Genomic structure around joining segments and constant regions of swine T-cell receptor alpha/delta (TRA/TRD) locus

A complete genomic region of 131.2 kb including the swine T-cell receptor alpha/delta constant region (TRAC/TRDC) and joining segments (TRAJ/TRDJ) was sequenced. The structure of this region was strikingly conserved in comparison to that of human or mouse. All of the 61 TRAJ segments detected in the human genomic sequence were detected in the swine sequence and the sequence of the protein binding site of T early alpha, the sequence of the alpha enhancer element and the conserved sequence block between TRAJ3 and TRAJ4 are highly conserved. Insertion of the repetitive sequences that interspersed after the differentiation of the species in mammals such as short interspersed nucleotide elements is markedly suppressed in comparison to other genomic regions, while the composition of the mammalian-wide interspersed sequences is relatively conserved in human and swine. This observation indicates the existence of a highly selective pressure to conserve this genomic region around TRAJ throughout the evolution of mammals.     

Regional difference in the appearance of apoptotic cell death in the ligamentum flavum of the human cervical spine

Ossification or calcification of the ligamentum flavum (LF) is relatively common in the middle and lower cervical, thoracic, and lumbar spine but extremely rare in the upper cervical region. This clinical fact suggests that there exist local factors promoting or preventing ossification or calcification of LF. However, little is known about the differences in the ultrastructure and cellular alterations of the LF between the different spinal levels, even in the cervical spine. With electron microscopy, we examined samples of LF collected surgically from the upper and lower cervical spine regions; we then studied the apoptotic appearance of ligament cells using a preferential labeling method. We found direct evidence of apoptosis of ligament cells in the LF. Apoptosis was more apparent in the upper region samples than in the lower region samples. The spaces around the normal fibroblasts were filled with thick collagen fibrils, but the collagen fibrils disappeared around the apoptotic bodies and thin fibrils were formed. The difference of the level of apoptosis may correlate to the ultrastructual difference of LF, and our data will benefit further investigations seeking to clarify the mechanism of various pathological conditions in the human LF.     

Increased matrix metalloproteinase-9 activity in human ovarian cancer cells cultured with conditioned medium from human peritoneal tissue

Ovarian cancer cells disseminate by attachment to the peritoneal mesothelial cell surface of the abdominal cavity. We therefore investigated the influence of conditioned medium (CM) from human peritoneal tissues and mesothelial cells on the secretion of matrix metalloproteinases (MMPs) by ovarian cancer cells. The molecular weights of MMPs stimulating factors derived from human peritoneal tissues and mesothelial cells were estimated using microconcentrators with various cut-off membranes. Human peritoneal tissues were obtained from 12 surgical patients, and mesothelial cells were isolated from three peritoneal specimens. Exposure to CM from peritoneal tissue caused a concentration-dependent increase of the MMP-2 and MMP-9 bands in CM from NOM1 ovarian cancer cells, as shown by zymography. There was a significant difference in the increase of MMP-2 and MMP-9 (2.46-fold and 7.14-fold, respectively, at 0.4mg/ml protein; P < 0.005). CM from mesothelial cells also significantly increased the secretion of MMP-9 by NOM1 cells. The molecular size of possible MMP-9-stimulating factors secreted by peritoneal tissues and mesothelial cells was above M 100000. Further, CM of peritoneal tissues and mesothelial cells also induced the invasiveness of NOM1 cells. These findings suggest that mesothelial cells may secrete some factors which predominantly induce the MMP-9 production and increase invading cell numbers.     

Cationic polymerization of vinyl monomers with latent initiators, 3. 1-(p-methoxybenzyl)tetrahydrothiophenium hexafluoroantimonate as a new potent cationic initiator

Cationic polymerization of styrene in the presence of 1-(p-methoxybenzyl)tetrahydrothiophenium hexafluoroantimonate ( 3 ) as an efficient cationic initiator was investigated. 3 was synthesized in an excellent yield by the reaction of p-methoxybenzyl bromide with tetrahydrothiophene and the subsequent exchange of bromide ions for hexafluoroantimonate ions. In the polymerization of styrene, 3 acted as a potent thermally latent initiator which initiates the polymerization at a slightly higher temperature than room temperature, although no polymerization occurs at room temperature for 30 min. 3 is a much more active initiator than the previously reported benzylsulfonium salt 1 . The enhanced activity of 3 was also confirmed in the polymerization of glycidyl^b phenyl ether.     

Cloned Th cells confer eosinophilic inflammation and bronchial hyperresponsiveness

BACKGROUND: The essential role of Th cells and T cell cytokines in eosinophilic inflammation has been established. METHODS: To determine whether Th cells are sufficient for the development of airway eosinophilic inflammation, ovalbumin-reactive murine Th clones were established and infused into unprimed mice. RESULTS: Eosinophilic infiltration into the lung was induced upon antigen inhalation in parallel with the rise in bronchoalveolar lavage fluid (BALF) eosinophil peroxidase activity. Neither IgG, IgA, nor IgE antibodies were present in this model. Pathological examination showed swelling and desquamation of epithelial cells, mucous plugs, and goblet cell hyperplasia, all of which well resemble human asthma. Fluorescent probe labeled Th clones migrated into the lung prior to the eosinophil accumulation. Bronchial hyperresponsiveness (BHR) was clearly induced upon antigen inhalation. Anti-IL-5 monoclonal antibody abrogated the responses. Dexamethasone and cyclosporin A suppressed cytokine production by Th cells both in vitro and in vivo, BALF eosinophilia, and BHR. The number of eosinophils recovered in the BALF correlated with the intensity of BHR. CONCLUSION: The results clearly indicated that monoclonal Th cells are sufficient for the development of both airway eosinophilia and BHR. Agents capable of downregulating IL-5 production seem promising for the treatment of bronchial asthma.     

Morphologic Development of Fetal Rabbit Lung and Its Acceleration with Cortisol

The influence of cortisol on the maturation of fetal lungs of rabbits has been studied. The normal developmental pattern of the various lobes is also documented and it is shown that there is a definite sequence of maturation among the five lobes of the lung. At a given gestational age, both upper lobes are consistently most mature. The right middle lobe is somewhat less mature while right and left lower lobes are least mature. The difference in the rate of maturation between the most advanced right apex and the least advanced base of lower lobes is as much as 1½ days out of a total gestation of 30 days. Cortisol, injected into the fetuses 2 days prior to delivery, accelerated the overall maturation of the lung by about 1½ days. The maturation of the type II epithelial cells also was accelerated and their inclusion bodies were more numerous than those of the controls. As reported elsewhere, prematurely delivered cortisol-injected rabbits of 26 to 28 days' gestation are more viable, breathe better and their lungs are better aerated when compared with control littermates. The surface activity of the alveolar lining of these animals is greater than that of the controls as indicated by higher ratios of bubble stability. These findings are apparently the results of accelerated maturation of the type II alveolar epithelial cells, which contain surfactant or its precursors as inclusions within the cytoplasm.     

Fibronectin activates matrix metalloproteinase-9 secretion via the MEK1-MAPK and the PI3K-Akt pathways in ovarian cancer cells

Cell adhesion to the extracellular matrix appears to trigger a cascade of intracellular signalings. We have previously shown that treatment of ovarian cancer cells, NOM1, with fibronectin (FN) stimulated matrix metalloproteinase (MMP)-9 secretion and thereby activated the invasiveness of cells via the FAK/Ras signaling pathway. By use of chemical inhibitors, we investigated the downstream effectors critical for FN-dependent secretion of MMP-9. Treatment of cells with MEK1 inhibitors, U0126 and PD98059, dramatically suppressed the secretion of MMP-9 activated by FN. Similarly, PI-3 kinase inhibitors, Wortmannin and LY294002, strongly suppressed the FN-dependent secretion of MMP-9 together with the inhibition of Akt activation. In contrast, a specific PKC inhibitor (GF109203X) showed no inhibitory effect on the FN-dependent MMP-9 secretion. Moreover, we found that both the MEK1 inhibitor and the PI3-K inhibitor, but not the PKC inhibitor, strongly suppressed the invasiveness of NOM1 cells. Taken together, our results suggest that activation of dual signaling pathways, MEK1-MAPK and PI3K-Akt, is required for the FN-dependent activation of MMP-9 secretion. Our results suggest the importance of these signaling molecules as a chemotherapeutic target for cancer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Morphometry of right ventricular hypertrophy induced by myocardial infarction in the rat.

The growth response of the right ventricle was studied in rats following ligation of the left coronary artery, which produced infarcts comprising approximately 40% of the left ventricle. A month after surgery the weight of the right ventricle was increased 30%, and this hypertrophic change was characterized by a 17% wall thickening, consistent with the 13% greater diameter of myocytes. Myocardial hypertrophy was accompanied by an inadequate growth of the microvasculature that supports tissue oxygenation. This was seen by relative decreases in capillary luminal volume density (-27%) and capillary luminal surface density (-21%) and by an increase in the average maximum distance from the capillary wall to the mitochondria of myocytes (19%). In contrast, measurements of the mean myocyte volume per nucleus showed a proportional enlargement of these cells (32%), from 16,300 cu mu in control animals to 21,500 cu mu in experimental rats. Quantitative analysis of the right coronary artery revealed a 33% increase in its luminal area, commensurate with the magnitude of ventricular hypertrophy.