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Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

At least 577 records · Page 32Linked to original sources
PubMed1992

Possible role of the vascular renin-angiotensin system in hypertension and vascular hypertrophy.

To investigate the vascular renin-angiotensin system in two-kidney, one clip (2K1C) hypertension, we measured angiotensinogen messenger RNA (mRNA) in the aorta and aortic and plasma angiotensin II (Ang II) concentration in 2K1C rats during early (4 weeks) and chronic (16 weeks) phases. Four weeks after clipping, there was no significant change in aortic angiotensinogen mRNA in both groups. However, the levels of plasma and aortic Ang II in 2K1C rats were significantly elevated compared with levels in control rats (p less than 0.05). Sixteen weeks after clipping, aortic angiotensinogen mRNA in 2K1C rats did not differ compared with the level in control rats. The aortic Ang II level in 2K1C rats was significantly increased compared with that in control rats (p less than 0.05), whereas there was no significant difference in the plasma Ang II level between the groups during this chronic phase. During both phases, morphological studies in 2K1C rats showed arteriosclerotic changes, with a significant increase in the wall-to-lumen ratio (p less than 0.01). The present study is the first to demonstrate an increase in vascular Ang II levels and concomitant morphological arteriosclerotic changes during both the early and chronic phases in 2K1C rats. Together with the results of our previous study that demonstrated an elevation of vascular renin activity during the early phase and increased vascular angiotensin converting enzyme activity during the chronic phase, we conclude that the elevated vascular renin activity and vascular angiotensin converting enzyme activity during each phase may play a dominant role in the increase in vascular Ang II observed during both phases.

Angiotensin I↗
PubMed1992

Increase of angiotensin converting enzyme gene expression in the hypertensive aorta.

To investigate the possible role of vascular angiotensin converting enzyme (ACE) in the development and maintenance of hypertension, we examined aortic ACE messenger RNA (mRNA) levels in two-kidney, one clip (2K1C) hypertensive rats. The blood pressure was increased remarkably at 4 weeks (early stage) after clipping and remained elevated at 12 weeks (chronic stage). The aorta ACE mRNA levels were significantly elevated in both early and chronic stages concurrently with the increases in aortic ACE activity and blood pressure. The plasma renin activity rose markedly at 4 weeks, but returned to the normal level at 12 weeks. Neither ACE activity in the lung and plasma, nor ACE mRNA level in the lung was altered at either stage. The aorta and liver angiotensinogen mRNA levels and renal renin mRNA level were increased at 4 weeks but decreased at 12 weeks. These results indicate that the acceleration of all components in the renin-angiotensin system may contribute to the development of 2K1C hypertension in the early stage. In the chronic stage, the increased vascular ACE induced by the elevated ACE mRNA levels in the aorta may play the primary role in the acceleration of local angiotensin II formation and thus may sustain the hypertension.

Angiotensinogen↗
PubMed1992

Distinct responses of interleukin-6 and other laboratory parameters to treatment in a patient with polyarteritis nodosa--a case report.

The authors describe a patient in whom the serum levels of interleukin-6 (IL-6) and other laboratory parameters were monitored. The IL-6 and C-reactive protein (CRP) levels, which were extremely high before treatment, declined rapidly with administration of prednisolone. Rheumatoid factor, IgG, and platelets count declined more gradually. Thus, determination of the serum IL-6 level might be useful in diagnosing and monitoring polyarteritis nodosa.

Aged↗
PubMed1992

Circadian rhythm in patients with hydranencephaly.

Circadian rhythm and sleep were studied in three hydranencephalic infants who were diagnosed on the basis of computed tomographic and/or magnetic resonance imaging scans and electrophysiologic findings. In all three cases, although the active sleep cycle was preserved, quiet sleep decreased and indeterminate sleep increased. The sleep-circadian rhythm was disturbed in all three cases. The hormone secretion rhythm was studied in two cases (cases 1 and 3). In both cases, cortisol secretion showed two or three peaks during the day. In one case (case 3), growth hormone secretion did not show sleep enhancement. Prolactin secretion showed an increase during sleep in both cases. The circadian rhythm of body temperature appeared at 6 months of age and disappeared after 1 year of age in case 1. Case 2 did not show a circadian rhythm of body temperature, but case 3 did at 2 years 6 months of age. However, it was thought that the circadian rhythm of body temperature in case 3 was a false one due to severe opisthotonus. Thus, it is suggested that the development of the circadian rhythm may require the rostral brain structure more than the midbrain and that there may be multiple oscillators in humans.

Brain Stem↗
PubMed1992

A study of embolizing materials for chemo-embolization therapy of hepatocellular carcinoma: embolic effect of cisplatin albumin microspheres using chitin and chitosan in dogs, and changes of cisplatin content in blood and tissue.

Hepatic artery of dogs was embolized with cisplatin (CDDP) albumin microspheres containing chitin and chitosan to investigate the in vivo CDDP release kinetics from CDDP albumin microspheres, the CDDP cumulative characteristics in the liver, and the influence of microsphere administration on hepatic tissue. Results showed that changes in blood CDDP content were dependent on CDDP albumin microsphere type and that release kinetics were better sustained when chitin was added to the microspheres or when the microspheres were treated with chitosan. In particular, the administration of CDDP in the chitin-containing CDDP chitosan albumin microspheres showed a blood CDDP content of approximately 0.26 micrograms Pt/ml 14 d after administration. The administration of chitin-containing or chitosan treated CDDP microspheres showed a CDDP content in the hepatic tissue of 0.14 to 0.23 micrograms Pt/g 28 d after administration. They also showed better control of CDDP release than those without chitin or chitosan treatment. No CDDP influence on hepatic tissue was observed. We conclude that, even in vivo, chitin and chitosan are effective embolic materials.

Animals↗
PubMed1992

A study of embolizing materials for chemo-embolization therapy of hepatocellular carcinoma: antitumor effect of cis-diamminedichloroplatinum(II) albumin microspheres, containing chitin and treated with chitosan on rabbits with VX2 hepatic tumors.

As an effective therapy for hepatocellular carcinoma, hepatic arterial chemo-embolization therapy has been widely used, and many embolizing materials have been extensively investigated. In the present study, we prepared various types of cis-diamminedichloroplatinum(II) (CDDP) albumin microspheres using chitin and chitosan, both of which have attracted considerable attention as new non-toxic biological polymer materials having favorable characteristics such as immune adjuvant activity, biological compatibility, and biodegradation. Hepatic artery of rabbit hepatic cancer models, which had transplanted VX2 tumors, were embolized with various types of microspheres. The anti-tumor effects and tumor-targeting of the microspheres, and the effects of the microspheres administration on the hepatic tissue were investigated. As a result, anti-tumor activity of the microspheres was increased by the addition of chitin-containing or chitosan treated materials; tumor growth rates of chitin addition and chitosan treated groups were approximately 160% and 120%, respectively, and were significantly lower than that of the non-treatment groups with a rate of approximately 580%. However, complete inhibition of tumor growth might have been impossible. Anti-tumor activity was increased by the addition of chitin-containing or chitosan treated materials. Whereas the growth inhibitory effect was insufficient, in order to potentiate anti-tumor activity, higher CDDP contents and sustained release of CDDP at a high level from microsphere and so on should be essentially improved for the near future. The CDDP level in hepatic tissue following the administration of microspheres was increased by adding chitin to the microspheres or by treating the microspheres with chitosan.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1992

Changes in the interposed capsule after Chiari osteotomy. An experimental study on rabbits with acetabular dysplasia.

We have investigated the changes in the interposed capsule after a Chiari pelvic osteotomy, in an experimental study on dysplastic hips in 20 adolescent rabbits. Radiographic, macroscopic and microscopic observations were made up to 12 months after operation. The new acetabular roof had incorporated the interposed capsule and remodelled completely by six months. By 12 months there was a new, stable hip with continuity between the capsule and the original acetabular cartilage. Histologically, the capsule underwent metaplastic change to fibrocartilaginous tissue after six months, with some hyaline-like cartilage near the joint surface. These changes in the interposed capsule play an important role in the formation of a new joint after a Chiari pelvic osteotomy.

Acetabulum↗
PubMed1992

Antiproliferative effects of suramin on human cancer cells in vitro and in vivo.

The present experiment was undertaken to study what types of human cancers are responsive to the antiproliferative effects of suramin. The human malignant cells used were as follows: cervical cancer (HeLa), mammary cancer (MCF-7), bladder cancer (EJ), hepatoma (HuH-7, PLC/PRF/5), embryonal carcinoma (PA-1), in vitro transformed fibroblasts (KMST-6, SUSM-1, VA-13), five myeloma cell lines (KMM-1, KMS-5, KMS-11, KMS-12, RPMI 8226), Burkitt's lymphoma (Raji), acute promyelocytic leukemia (HL-60), chronic myelocytic leukemia (K562), Epstein-Barr virus nuclear antigen positive lymphoblastoid cells (KMS-9). The cells were treated with 25 to 100 micrograms/ml suramin for 72h. Proliferation of HuH-7 and two human myeloma cells (KMS-11 and KMS-12) was remarkably inhibited, and that of PA-1, PLC/PRF/5, KMST-6, two other myeloma cell lines (KMM-1 and KMS-5), Raji and HL-60, was moderately inhibited. In order to confirm part of the results obtained from in vitro experiments, in vivo experiments were also undertaken. The growth of HuH-7 cells transplanted subcutaneously into nude mice was significantly suppressed by intravenous injection of suramin. We discussed the possibility that certain types of human cancers, the growth of which seemed to be more or less dependent on polypeptide growth factors, might be sensitive to the antiproliferative effects of suramin.

Animals↗
PubMed1992

Increased frequency of the heterozygous switch region of IgA2 in Japanese patients with IgA nephropathy.

The relation between IgA hyperproduction and restriction fragment length polymorphism (RFLP) of the immunoglobulin heavy chain switch (S) region was examined in Japanese patients with IgA nephropathy (IgAN) using Southern blot hybridization. Polymorphism in the S regions of IgM, IgA1 and IgA2 (SA2) was detected. A significant increase in the frequency of heterozygous phenotype of SA2 was shown in the patients. These patients showed a significant increase in the amount of serum IgA, IgA bearing cells and levels of proteinuria. Although two reports on RFLP of the S region have been published in Europe, the results differed. A comparison of the three reports showed different frequencies in the phenotype of the S region between Caucasian and Japanese patients. These results suggested that there is heterogeneity at the S region in IgAN patients in various countries and that this polymorphism might be associated with IgA hyperproduction and the development of proteinuria in Japanese patients.

Adult↗
PubMed1992

Lupus nephritis associated with bacterial panperitonitis and lung alveolar hemorrhage.

A 36-year-old woman was admitted to the hospital with the diagnosis of nephrotic syndrome due to lupus nephritis. The patient had panperitonitis caused by Staphylococcus aureus as a complication, and an emergency laparotomy was performed. After the operation, the patient developed a massive lung alveolar hemorrhage. Methylprednisolone pulse therapy showed a marked effect on the lung hemorrhage. It is known that lung alveolar hemorrhages associated with systemic lupus erythematosus have a very high mortality; the present case is relatively rare because of the good response to steroid pulse therapy.

Adult↗
PubMed1992

Evaluation of complement in patients with eosinophilic pneumonia.

Complement evaluation was performed in two patients with active eosinophilic pneumonia and in one in remission, to determine the role of complement activation in the pathogenesis of this disorder. All three had cough, dyspnea, malaise, and blood eosinophilia; two patients also had pyrexia. In all 3 cases the pulmonary eosinophilic infiltrates (radiographic findings) and symptoms responded rapidly to steroid administration. The two patients with active eosinophilic pneumonia showed elevated CR3 but reduced FcrR on the PMN before and during steroid administration. In contrast PMN from four patients with bronchial asthma exhibited slightly elevated expression of both CR3 and FcrR during their asthma attack. It is suggested that clinical symptoms disappear soon after the beginning of steroid but changes of complement receptors on PMN may last for longer periods. On the basis of the combined results, this study indicates that estimation of complement activation may provide a useful indicator for disease activity in patients with eosinophilic pneumonia of unknown etiology.

Adult↗
PubMed1992

Simultaneous measurements of adenosine deaminase activity and tuberculostearic acid in pleural effusions for the diagnosis of tuberculous pleuritis.

Adenosine deaminase (ADA) activity and tuberculostearic acid (TSA) levels in pleural effusions were measured in 18 patients with active tuberculous pleuritis, 16 patients suspected of having tuberculous pleuritis, 14 patients with carcinomatous pleuritis, and 19 patients suffering from pleuritis of non-malignant and non-tuberculous etiology. In the patients with active tuberculous pleuritis, ADA was elevated in 56% and TSA was positive in 78%. In 83% of these patients, either ADA was elevated or TSA was positive. ADA was elevated together with a positive TSA in 50%. In contrast, TSA was positive in only 6% and ADA was elevated in 24% of the patients with non-tuberculous pleuritis, and none of these patients showed the combination of an elevation of ADA and a positive TSA. These results suggest that simultaneous measurements of both ADA and TSA in pleural effusions are useful for the diagnosis of tuberculous pleuritis.

Adenosine Deaminase↗
PubMed1992

Late-onset homozygous protein C deficiency manifesting cerebral infarction as the first symptom at age 27.

We report a 31-year-old female who had repeated thrombosis and was diagnosed as having congenital homozygous protein C deficiency based on decreased protein C antigen and activity, and the findings of family history. This patient had shown no symptom of thrombosis until the age of 27 years, when she had cerebral infarction as the first symptom. Low molecular weight heparin was useful for disseminated intravascular coagulation (DIC) that complicated protein C deficiency in this patient.

Adult↗
PubMed1992

[Hepatic protein synthesis and cytokines in obstructive jaundice].

UNLABELLED: To clarify the mechanism of the increase of hepatic protein synthesis observed in the obstructive jaundiced rats, hepatocellular protein synthesis (HPS) and secretory protein synthesis (SPS) were estimated in the rats with obstructive jaundice and the contents of the following in the peripheral blood were determined in 21 patients with obstructive jaundice before and two weeks after percutaneous transhepatic biliary drainage (PTBD): interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF alpha), endotoxin (Et), acute-phase protein (APP) and negative acute-phase protein (NAPP). THE RESULTS: (1) HPS and SPS were markedly increased by obstructive jaundice; (2) IL-1 beta and IL-6 were significantly high and were reduced after PTBD; (3) neither TNF alpha nor Et was detected; (4) APP were significantly high and failed to decline after PTBD; (5) NAPP were significantly low and the contents were restored to the normal levels after PTBD. These results suggest that increased hepatic protein synthesis observed in the rats with obstructive jaundice correspond to the increased hepatic production of APP in patients with obstructive jaundice.

Acute-Phase Proteins↗
PubMed1992

CD4 subsets in IgA nephropathy.

CD45RA+ (2H4+) and CD45RA-(CD29, 4B4+) antigenic expressions, recognized as a suppressor inducer and a helper inducer, respectively, on CD4+ and T alpha 4+ cells (Fc alpha receptor bearing CD4 T cells) were measured by three color flow cytometry in patients with IgA nephropathy (IgAN). The 4B4+ subsets of CD4 and T alpha 4 T cells were increased significantly in the patient group compared with the control group. The level of the 2H4+ subset did not differ between the two groups. No significant correlation was observed between the increase in the 4B4+ subset and disease severity, as estimated by measuring the proteinuria, levels of serum creatinine and immunoglobulins (Igs) or renal tissue damage. It was concluded that 4B4+ CD4+ and 4B4+ T alpha 4+ subsets might be involved in the mechanism of immunopathogenesis of IgA nephropathy.

Adult↗