Expression of MMP-2, MMP-9 and TIMP-1 in the Wall of Abdominal Aortic Aneurysms

An impaired mechanism of regulatory feedback by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) has been implicated in the development of abdominal aortic aneurysms (AAAs). This study examined the pathogenesis of AAAs with respect to pathological characteristics and expressions of MMP-2, MMP-9 and TIMP-1. Their expressions were evaluated by immunohistochemistry, competitive polymerase chain reaction (PCR) and Western blotting in a total of 23 consecutive AAAs. The AAA specimens were obtained by surgery, while control specimens were obtained at autopsy. Specimens consisted of 6 patients with small-diameter AAAs (30?45 mm), 17 with medium-large-diameter AAAs (> 45 mm) and 11 controls (17?25 mm). Immunohistochemistry showed MMP-2- and TIMP-1-positive cells mainly in the intima, and MMP-9-positive cells in the intima and adventitia. Competitive PCR showed a significantly higher expression of MMP-2 messenger RNA (mRNA) in the small-diameter AAAs, and higher expressions of MMP-9 mRNA in the small-diameter and medium-large-diameter AAAs than in the controls. The mRNA levels significantly correlated between TIMP-1 and MMP-9, and between MMP-2 and MMP-9 in the AAAs, especially in the medium-large-diameter AAAs. Western blotting revealed the expression of MMPs and TIMP-1 variably in all the specimens examined. These results indicated that MMP-2 and MMP-9 might act cooperatively and play a crucial role in the development of AAAs, and that TIMP-1 inhibits MMP-9 in the AAAs, especially in those medium-large-diameter AAAs

Activated Protein Kinase C Attenuates Ca2+ Overloading and Reoxygenation Hypercontracture in Isolated Rat Cardiomyocytes following Chemical Hypoxia

The aims of this study were i) to test the effects of protein kinase C (PKC) activation on the intracellular Ca2+ concentration of rat cardiomyocytes during chemical hypoxia-reoxygenation, ii) to determine the contribution of the sarcoplasmic reticulum (SR) and the Na+-Ca2+ exchange on the regulation of intracellular Ca2+ following PKC activation and iii) to test the role of PKC-dependent intracellular pH changes in intracellular Ca2+ regulation. We used the isolated adult rat cardiomyocyte perfusion model. Cardiomyocytes were loaded with the Ca2+-fluorescent probe Fluo-3 and the pH-fluorescent probe SNARF1. Cells were subjected to 50 min of glucose-free and NaCN chemical hypoxia followed by 30 min of simulated reoxygenation. The activation of PKC significantly inhibited the hypoxia-induced increase of Fluo-3 fluorescent intensity (control; 692 ± 100% and activated PKC; 322 ± 43%: P < 0.05). This inhibitory effect was not affected by the inhibition of the SR Ca2+ uptake induced by thapsigargin, but was cancelled by the inhibition of the Na+-Ca2+ exchange with dichlorobenzamil (thapsigargin 337 ± 47%; dichlorobenzamil 609 ± 100%). PKC activation also attenuated the decrease in intracellular pH during chemical hypoxia, even in the presence of the Na+-H+ exchange inhibitor amiloride (control; 6.54 ± 0.02, PKC; 6.72 ± 0.03, PKC + amiloride; 6.73 ± 0.03). We concluded that the PKC attenuation of Ca2+ overloading to rat cardiomyocytes during chemical hypoxia-reoxygenation does not depend on the Ca2+ uptake by the SR, but does require a Na+-Ca2+ exchange. Since PKC attenuated the increasing intracellular H+ during chemical hypoxia, a low H+ concentration may be important for the maintenance of Ca2+ extrusion via the Na+-Ca2+ exchange

Tyrosine Phosphorylation Regulates the Expression of Major Histocompatibility Complex Antigens on a Human Lung Cancer Cell Line by Interferon-gamma

Expression of major histocompatibility complex (MHC) antigens on cancer cells is essential for cell-mediated immune function. However, these molecules are reduced on cancer cells enabling them to escape from host immune surveillance. It is well known that interferon-γ (IFN-γ) upregulates the expression of MHC molecules and restores the immunogenicity of cancer cells. Nevertheless, the mechanism by which IFN-γ modulates MHC expression on cancer cells is not clear. Therefore, in this report, we examined the role of tyrosine protein kinases in IFN-γ-induced MHC expression in a human lung adenocarcinoma cell line, HLC-1. We found that a tyrosine protein kinase inhibitor, herbimycin A, inhibited both IFN-γ-inducible MHC class I and class II expression, as assessed by flow cytometry. Additionally, assessment of tyrosine phosphorylation of cellular substrates by confocal laser microscopy using an anti-phosphotyrosine monoclonal antibody (mAb) revealed that IFN-γ induced protein tyrosine phosphorylation within 5 min of treatment. Herbimycin A inhibited this IFN-γ-induced tyrosine phosphorylation. Thus, tyrosine phosphorylation plays an important role in IFN-γ-induced MHC class I and class II expression on HLC-1 cells

Induction of Apoptosis of Rat Neonatal Cardiomyocytes by Chemical Ischemia and Reoxygenation: The Role of Phosphatidylserine

Ischemia/reperfusion injury plays a crucial role in the induction of the cell death of myocytes. The precise mechanism of the cell death, however, has not been elucidated enough. This study examined the cell death of rat neonatal myocytes induced by chemical ischemia and reoxygenation with an in vitro model, in terms of apoptosis, and the role of phosphatidylserine, which is recognized with annexin V. Chemical ischemia and reoxygenation were conducted on the cultured myocytes obtained from 1- or 2-day-old Wistar rats. The cells were divided into 4 groups exposed to chemical ischemia for 9 h (Group A), 18 h (Group B) and 24 h (Group C) and one group not exposed to chemical ischemia (Control Group). DNA ladder formation on agarose gel electrophoresis was noted in Groups B and C followed by reoxygenation, but not in Group A, as well as all 4 groups without reoxygenation. There were cells positive to terminal deoxynucleotidyl transferase-mediated dUDP-biotin nick end labeling in all 3 groups except for the Control Group; after reoxygenation, the number of cells became larger in Groups B and C than in Group A. Flow cytometry revealed that annexin V-positive cells were 1.15 ± 0.82% in the Control Group, 4.07 ± 3.8% in Group A without reoxygenation and 15.5 ± 6.3% in Group A after 30-min reoxygenation, respectively; the value was significantly higher in the latter than the former two (P < 0.01). Although 18-h and 24-h ischemia increased the annexin V-positive cells, reoxygenation did not alter the number of cells in Groups B and C. These results indicate that i) chemical ischemia followed by reoxygenation variably induces apoptosis of rat myocytes, ii) long-term ischemia causes phosphatidylserine translocation on the cell surface membrane, regardless of reoxygenation and iii) mild ischemia necessitates reoxygenation to translocate phosphatidylserine, which might play a crucial role in the initiation of apoptosis of the myocytes

Genomic Organization of the Human Arpp Gene

A novel ankyrin-repeated protein, Arpp, is specifically expressed in skeletal and cardiac muscles. Arpp protein is homologous, in its amino acid sequences (52.7% identity), to Carp protein which is proposed to be a putative genetic marker for cardiac hypertrophy. In this study, we isolated the human Arpp gene by screening a human genomic library and analyzed the genomic structure and its 5' flanking region. The Arpp gene was found to encompass a sequence of 11 kb and to consist of 9 exons. The translational initiation site and the stop codon were found to be located at exon 1 and exon 9, respectively. Each exon from 5 to 8 was found to encode 1 of the 4 ankyrin-like domains, respectively. The 2.7 kb upstream of exon 1 was sequenced. The TATA box was identified 29 bp upstream of the transcriptional start site, and multiple putative regulatory elements including the E box and upstream stimulating factor-1 were distributed within the proximal promoter regions. Since these elements were also found in the promoter region of the mouse Arpp gene, they may play an important role in the transcriptional regulation of both human and murine Arpp genes

A Case of Catamenial Pneumothorax Treated by Video-Assisted Thoracoscopic Surgery

This is a case of a 47-year-old female who had a medical history of right pneumothorax for the second time. The pneumothorax, accompanying the start of menstruation, recurred and the patient was hospitalized. From the medical history, a catamenial pneumothorax was suspected. As for intraoperative findings, many small fenestrations of 1 mm or 3 mm were present in the border region with the muscle bundle of the central tendon of the diaphragm. The lesion site of the diaphragm and the apex area as a biopsy were partially excised under video-assisted thoracoscopic surgery. Although a postoperative Gn-RH agonist was started for endometriosis, it was stopped because side effects appeared. Because the right pneumothorax recurred in accordance with the start of menstruation, the treatment was changed to danazol. To date, the pneumothorax has not recurred