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Biomedical subjects

T Nonaka

Publications and source records attributed to T Nonaka.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Significance of serine proteinase and matrix metalloproteinase systems in the destruction of human articular cartilage.

1. During the destruction of articular cartilage, fibrinolytic enzymes and matrix metalloproteinases (MMP) may contribute to the related pathology. The activities, antigens and messenger RNA (mRNA) levels of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in articular cartilage were measured in patients with no history of joint diseases (control), those with osteoarthritis (OA) classified into osteophyte-formed site (OS) and weight-bearing site (WS), and in patients with rheumatoid arthritis (RA). 2. The uPA content was higher in WS and RA compared to normal. The PAI-1 content was higher in OS and RA compared to normal. Weight-bearing site patients expressed a high uPA mRNA level but a low PAI-1 mRNA level. Osteophyte-formed site patients expressed a low uPA mRNA level but a high PAI-1 mRNA level. 3. The levels of the MMP and mRNA of tissue inhibitors of metalloproteinases (TIMP) were measured in WS, OS, and RA. In WS, the levels of MMP were high and levels of TIMP mRNA expression low. In OS, the levels of TIMP were high and levels of MMP mRNA were low. In RA, the levels of MMP and TIMP mRNA were high. 4. These findings suggest that regulation of fibrinolysis may play an important role in the matrix of articular cartilage with arthropathy.

Aged↗
PubMedDate not supplied

Mutation of the core region of HBV-DNA and submassive hepatic necrosis in patients with anti-HBe-positive chronic hepatitis B.

Three patients with submassive hepatic necrosis developed acute liver failure during the severe reactivation of chronic hepatitis B. The activity of hepatitis B virus (HBV) DNA polymerase increased in all three patients immediately before the onset of hepatic failure. Liver biopsy specimens obtained before and after the episode of submassive hepatic necrosis showed progression to advanced liver cirrhosis. The nucleotide sequences of the precore and core regions of HBV-DNA were investigated in two of the three patients and in another two patients with piecemeal and bridging necrosis. The nucleotide and amino acid sequences of the HBV-DNA core region changed after reactivation in the the two patients with submassive hepatic necrosis, while the sequences in the other two patients with piecemeal necrosis remained unchanged before and after reactivation. These results suggest that the antigenicity of the HBV-DNA core region may have been changed before and after severe reactivation. Due to mutation at the core region, a different type of epitope would be expressed on the hepatocytes after submassive hepatic necrosis, which would not be a target for the cytotoxic T cell. This was evident by the continuation of the normal serum GPT for 5 and 9 years, respectively.

Adult↗
PubMedDate not supplied

Significance of sublobular hepatic necrosis in the progression of chronic hepatitis C.

The clinical characteristics of hepatitis C virus associated chronic liver diseases (C-LD) in 17 patients were compared with hepatitis B virus associated diseases (B-LD) in 47 patients, by analysing the histological findings of the liver and the change in serum alanine aminotransferase (ALT) level. The persistence of the moderate abnormality in ALT (> 100 IU/L) for longer than 1 year was more frequently seen in the C-LD group (P < 0.01), although the severe exacerbation of the disease with ALT higher than 500 IU/L was more frequent in the B-LD group (P < 0.01). The patients with the histological finding of sublobular hepatic necrosis (SN) in the C-LD group progressed to advanced stages more frequently than those with SN in the B-LD group (P < 0.05). Furthermore, nine of 10 patients with SN in C-LD finally progressed to hepatocellular carcinoma (HCC) in 52 +/- 23 months, whereas three of 16 with SN in B-LD developed HCC in 81 +/- 34 months. Although the morphological features of SN in C-LD and B-LD were almost the same, SN in C-LD seemed to be a more significant diagnostic condition for the progression to liver cirrhosis or HCC. The patients with SN in the C-LD group should be closely followed for the early detection of HCC, although further study with a greater number of patients is necessary.

Adult↗
PubMedDate not supplied

The seroepidemiology of hepatitis A and B in a Japanese town.

Sera collected from 1,118 healthy children and adults aged between four years and 90 years during the period 1989 to 1990, were tested for serological markers of hepatitis A virus (HAV) [antibody to HAV (anti-HAV)] and hepatitis B virus (HBV) [hepatitis B surface antigen (HBsAg) and antibody to hepatitis B surface antigen (anti-HBsAb)]. The overall prevalence rates of anti-HAV, HBsAg, and anti-HBV were 20.2%, 0.36%, and 5.1%, respectively. No body was found to be positive for anti-HAV below 30 years of age but more than 70% of the adults aged 50 years or over were positive for anti-HAV. The level of exposure of HAV infection is declining in Japan and paradoxically at the same time a vast majority of people are becoming susceptible to more severe illness. The fall in prevalence of HBsAg possibly represents the positive impact of ongoing vaccination programs and other preventive measures against HBV.

Adolescent↗
PubMedDate not supplied

The 5-hydroxytryptamine2A receptor antagonist sarpogrelate hydrochloride inhibits acute platelet aggregation in injured endothelium.

In this study, the effect of sarpogrelate hydrochloride, a 5-hydroxytryptamine2A receptor antagonist, on platelet aggregation at the site of injured carotid artery endothelium was examined. The rat common carotid artery was clamped for 30 min to induce endothelial injury. Sarpogrelate hydrochloride was administered before and after the injury, and the effects were compared with those in rats receiving sham operation only and those receiving clipping injury but no sarpogrelate hydrochloride. The animals were killed 24 h after the procedure. The common carotid artery was examined by scanning electron microscopy and stained immunochemically for factor VIII. Sarpogrelate hydrochloride treatment was associated with reduced aggregation of platelets on electron microscopy and lower expression of factor VIII at the injured intima. Sarpogrelate hydrochloride has an inhibitory effect on platelet aggregation at the intima in the acute stage after injury, suggesting that this drug may be used to prevent early ischaemic complications after surgical or endovascular arterial intervention.

Animals↗
PubMedDate not supplied

Freeze-etching study of human and murine leprosy bacilli.

Morphologic features of the electron transparent zone (ETZ) material around human and murine leprosy bacilli were examined by a freeze-etching technic. The ETZ around human leprosy bacilli is composed of spherical droplets of hydrophobic material. These are always liquid at body temperature and they never show crystalline lamellar structure even at the temperature of liquid nitrogen. The ETZ around murine leprosy bacilli is composed of ribbon-like or membranous crystalline structures. This material is solid and crystalline at the body temperature of mice, and this solid material is the chief cause of the random arrangement of murine leprosy bacilli inside the cytoplasm of murine lepra cells. This crystalline structure has also been observed around murine leprosy bacilli grown on cell-free culture media.

Cell-Free System↗