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Biomedical subjects

T Miyazaki

Publications and source records attributed to T Miyazaki.

At least 595 records · Page 33Linked to original sources
PubMed1991

Increased density of fluorescent adrenergic fibers around the middle cerebral arteries of stroke-prone spontaneously hypertensive rats.

The distribution of fluorescent adrenergic nerve fibers in the proximal portion (horizontal segment, Hs) and the three distal portions (major branches) of the middle cerebral arteries (MCA) was examined in stroke-prone spontaneously hypertensive rats (SHRSP) aged 10, 30, 60, 90, and 180 days, by the glyoxylic acid method. The results were compared with those in age-matched normotensive Wistar Kyoto (WKY) rats. While the distribution pattern of fluorescent nerve fibers in the proximal portion of WKY rats changed from a straight linear arrangement at 10 and 30 days of age to a network-like arrangement after 60 days, those from SHRSP showed a constant meshwork pattern throughout the entire examination period. In the distal portions of the MCA of both SHRSP and WKY rats at all ages examined, fluorescent nerve fibers formed a coarse network. The distribution densities of adrenergic nerve fibers in the proximal and distal portions of the MCA of SHRSP were significantly higher (P less than 0.01 and 0.05) than those of WKY rats at all ages examined, except in the proximal portion at 90 and 180 days of age. The difference in nerve fiber density between SHRSP and WKY rats reached a peak at 30 days of age in both proximal and distal portions, and then gradually decreased with age. The present study suggests that sympathetic hyperinnervation is an important factor in the development of hypertension, and is involved in its maintenance in SHRSP.

Adrenergic Fibers↗
PubMed1991

Immunogenetic study of thyroid hormone autoantibodies in a family.

Haplotypes of the human major histocompatibility complex (HLA) and immunoglobulin G heavy chain allotype (Gm) were determined in nine members of a family in which three sisters had thyroid hormone autoantibodies (THAA) in serum. Among three sisters with THAA, two of them were hypothyroid and treated with synthetic thyroid hormones (patients nos. 1 and 2). The other remaining sister (patient no. 3) was euthyroid. Light chain allotype (Km) in them was also examined. Three patients had the same two Gm haplotypes. Km (1) allotype was negative in these three patients. HLA haplotypes of patient no. 1 were the same as those of patient no. 2. However, HLA haplotypes of patient no. 3 were completely different from those of patients nos. 1 and 2. The same combination of Gm haplotypes and the absence of Km (1) allotype were not observed in the remaining members without THAA. These results suggest that genes linked to Gm and Km allotypes are associated with the production of THAA at least in our patients.

Autoantibodies↗
PubMed1991

Identification of aldosterone metabolites formed by A6 cells.

The A6 cell line of the toad kidney is well known to form an Na+ transporting tight epithelium in culture and is often used as an experimental model for Na+ transport systems. Although it has been shown that A6 cells can convert aldosterone to polar metabolites, these metabolites have not been identified. Therefore, in this study, we tried to identify the metabolites of aldosterone formed by A6 cells in culture. A6 cells at confluence were incubated with serum-free culture media containing [3H]aldosterone. When radioactive compounds in incubation media were separated by reversed phase high-pressure liquid chromatography (HPLC), four fractions (fractions A-D) were obtained. Fraction A, a mixture of two components, comprised the majority of metabolites formed. The more polar material (fraction A-1) and the less polar material (fraction A-2) of fraction A contained 47-71 and 9-19% of total radioactivity, respectively. When incubated in cell-free media, fraction A-2 was found to be unstable and partially converted to fraction A-1. Fraction B, 0.7-1.5% of total radioactivity, and fraction C, 8-21% of total radioactivity, cochromatographed with iso-aldosterone and D-aldosterone, respectively. Fraction D, 4-8% of total radioactivity, was a mixture of two components, which cochromatographed with 3 beta,5 beta-tetrahydroaldosterone and 5 alpha-dihydroaldosterone, respectively. In order to identify fraction A-2 material, large-scale cultures were performed and fraction A-2 was separated and purified by reversed phase HPLC. The purified material was analyzed by fast atom bombardment mass spectrometry and nuclear magnetic resonance spectroscopy. These two procedures unambiguously revealed that this material was 6 beta-hydroxyaldosterone. These results demonstrate that aldosterone can be converted to at least four metabolites by the incubation with A6 cells, and that major metabolites are polar compounds, a portion of which is 6 beta-hydroxyaldosterone.

Aldosterone↗
PubMed1991

Do prostaglandins lead to ovulation in the rabbit by stimulating proteolytic enzyme activity?

OBJECTIVE: To determine if prostaglandins (PGs) have a direct effect on the ovarian proteolytic enzyme system by examining ultrastructure of the follicle wall and the microvasculature in the presence and absence of indomethacin and by using the isolated perfused rabbit ovary. DESIGN: Nine hours after administration of human chorionic gonadotropin (hCG) or hCG plus indomethacin, follicles were removed and processed for scanning and transmission electron microscopy. Isolated perfused rabbit ovaries were induced to ovulate with PGF2 alpha (100 ng/mL) in the presence and absence of tranexamic acid (0.1, 1.0, or 10 mM), a plasminogen activator inhibitor. RESULTS: The addition of indomethacin to hCG inhibited ovulation and production of PGs without affecting the follicular microvasculature. However, the changes in follicle wall architecture were less pronounced after treatment with indomethacin. Ovulatory efficiency in response to PGF2 alpha (the percent of follicles greater than 1.5 mm that ovulate) was significantly reduced (P less than 0.01) by 10 mM tranexamic acid. CONCLUSIONS: These results suggest that PGs induce follicular rupture by activation of proteolytic enzymes located in the follicle wall.

Animals↗
PubMed1991

Protective role of superoxide dismutase in human sperm motility: superoxide dismutase activity and lipid peroxide in human seminal plasma and spermatozoa.

The levels of superoxide dismutase (SOD), a highly specific scavenging enzyme for superoxide anion radicals (O2-), and lipid peroxide produced by oxygen free radicals were measured in human seminal plasma and spermatozoa. Seminal plasma contained 366.8 +/- 20.9 U/ml (mean +/- SE) of SOD activity. SOD activity in human spermatozoa showed a significant correlation to the number of motile spermatozoa, while the activity in seminal plasma did not relate to the sperm concentration or motility. The lipid peroxide concentration in seminal plasma was 6.22 +/- 0.46 nmol/ml and had no significant relationship to sperm concentration or motility. The malondialdehyde (MDA) concentration in spermatozoa was significantly related to the number of immotile spermatozoa. A decrease in the motility of spermatozoa incubated in medium without seminal plasma was observed after 120 min, while the MDA concentration of the spermatozoa increased. Addition of exogenous SOD (400 U/ml) to the sperm suspension significantly decreased this loss of motility and the increase of the MDA concentration. These data suggest a significant role for SOD in sperm motility. It seems that lipid peroxidation of human spermatozoa may cause loss of motility and that SOD may inhibit this lipid peroxidation. These results suggest that SOD may have a possible clinical application in the use of spermatozoa for in-vitro fertilization (IVF) or artificial insemination.

Humans↗
PubMed1991

Effect of acetylpolyamines on in vitro protein synthesis and on the growth of a polyamine-requiring mutant of Escherichia coli.

The functions of acetylpolyamines were examined with respect to stimulation of protein synthesis and cell growth. Unlike polyamines, acetylpolyamines could not lower the optimal Mg2+ concentration of protein synthesis, and the degree of stimulation of protein synthesis by acetylpolyamines was small. The addition of N1-acetylspermine did not stimulate cell growth of a polyamine-requiring mutant of Escherichia coli MA261, although acetylspermine was accumulated in the cells. Acetylspermine did not interfere with polyamine stimulation of protein synthesis and cell growth of E. coli MA261. The binding of acetylpolyamines to RNA was very weak, and the binding of polyamines to RNA was not disturbed significantly by the presence of acetylpolyamines. When the growth of E. coli MA261 was stimulated by addition of polyamines, significant amounts of acetylpolyamines were also formed in the cells. These results suggest that acetylation of polyamines, together with polyamine excretion, may regulate the intracellular level of the parent polyamines when excess amounts of polyamines accumulate intracellularly.

Acetylation↗
PubMed1991

Increased N-acetylglucosamine-1-phosphotransferase activity in sera from patients with leukemia.

In human cancer, lysosomal hydrolases contain increased amounts of phosphorylated sugar chains. Sugar chains of the hydrolases undergo post-translational processing which is catalyzed by N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) at the first step. In the present study we estimated serum GlcNAc-phosphotransferase in 50 adults suffering from leukemia and myelodysplastic syndrome. The serum GlcNAc-phosphotransferase was increased to moderate or high levels in patients with acute nonlymphocytic leukemia (ANLL), acute lymphoblastic leukemia and chronic myelogenous leukemia, suggesting that the serum transferase is released from leukemic cells. In many cases of ANLL examined, activity of the transferase was decreased concomitantly with reduction of peripheral blastic cells by effective chemotherapy.

Acetyltransferases↗
PubMed1991

Establishment and characterization of a plasma cell leukaemia cell line dependent for growth on IL-6 and a bi-phenotypic subclone dependent upon both IL-3 and IL-6.

A human plasma cell leukaemia cell line (HSM-2) and a subclone (HSM-2.3) have been established from the bone marrow of a patient with bi-phenotypic leukaemia. Proliferation assays using a variety of cytokines demonstrated that HSM-2 proliferated in response to recombinant interleukin-6 (rIL-6), but did not respond to rIL-1, rIL-2, rIL-3, rIL-4, rIL-5, recombinant granulocyte-colony stimulating factor (rG-CSF), or recombinant granulocyte-macrophage-colony stimulating factor (rGM-CSF), and that HSM-2.3 responded to rIL-3 and rIL-6. HSM-2 expressed the CD38 (OKT10), PCA-1, cytoplasmic-IgM, and surface kappa light chain. HSM-2.3 expressed the CD14 (My4), CD33 (My9), CD38 (OKT10), CD19 (B4), CD24 (OKB2), CD10 (J5), PCA-1. HSM-2 and HSM-2.3 are useful tools for analysing the possible role of IL-3 and IL-6 in the oncogenesis of plasma cell leukaemia.

Aged↗
PubMed1991

[Analysis of 98 cases of thoracic empyema].

Ninety-eight cases of empyema thoracis admitted to Juntendo University Hospital between 1979 and 1990 were reviewed. Males accounted for 78 cases and females 20 cases. Thirteen pediatric patients ranged in age from 17 days to 4 years, while the 85 adult cases ranged from 16 to 89 years (mean: 58.4 years). The mortality rate increased with age. Fifty-three cases of community-acquired empyema thoracis consisted of 24 with no underlying disease (including 13 pediatric cases), and 29 with diabetes mellitus, alcoholic liver damage or chronic obstructive bronchopulmonary disease. Forty-five nosocomial empyema cases occurred after chest operation or thoracocentesis, or due to a subdiaphragmatic pathogenic condition or congestive heart failure complicated with aspiration pneumonia. In this series, 63 patients (64.3%) had para- or post-pneumonic empyema. Compared with the community-acquired infection cases, the mortality rate of the nosocomial infection cases was very high. Seventy-eight cases were culture-positive, including 3 positive for Mycobacterium tuberculosis. The remaining 20 cases were culture-negative. In 75 cases of culture-positive pleural fluid, aerobic bacteria were isolated from 31 cases (mortality rate: 22.6%), anaerobes mixed with aerobes from 21 cases (mortality rate: 52.4%), and anaerobes only from 23 cases (mortality rate: 21.7%). Thus, the mortality rate of mixed infected cases was highest. Anaerobes were frequently isolated from the community-acquired empyema cases, and were often found in para- or postpneumonic lesions, including aspiration pneumonia. The most commonly encountered aerobe was Staphylococcus aureus. Among the anaerobes, Bacteroides spp., microaerophilic streptococcus, Peptostreptococcus and Fusobacterium spp. were most common. A single organism was isolated in pure culture from 39 cases. Single organisms isolated from fluids were more frequently aerobes (25) than anaerobes (14). The cases harboring Bacteroides spp. showed the worst outcome, with 11 deaths in 25 such cases.

Adolescent↗
PubMed1991

[Laboratory and clinical investigation of lysis centrifugation blood culture method for fungemia].

We compared the lysis centrifugation blood culture system using Isolator (Du Pont) to the conventional blood culture bottle using BCB system (Roch), and the following results were obtained. In the investigation of experimental fungemia made by human blood and Candida albicans, the organism was detected 9/12 after 1 day and 11/12 after 3 days by Isolator, although the organism was detected 3/12 after 3 days and 11/12 after 6 days by the culture bottle system. In the experimental fungemia of Candida tropicalis, the organism was detected 12/12 after 2 days by Isolator, although it was detected 1/12 after 6 days and 4/12 after 10 days with the culture bottle system. Isolator showed faster and a more sensitive detection rate for fungemia. Clinical investigation of 94 cases (180 cultures) showed a 11.1% isolation rate with Isolator system and a 7.1% isolation rate with the culture bottle system. In 43 cases which were examined by the both systems, 7 cases were positive with Isolator, 3 positive with culture bottle. The culture bottle system isolated only Candida albicans and Candida parapsilosis, where as the Isolator isolated Candida albicans, Candida parapsilosis, Candida tropicalis, Candida krusei, and Candida spp. This investigation suggested that the Isolator system was an excellent method for the detection of fungemia.

Blood↗
PubMed1991

Pneumoperitoneum in a patient with lymphangiomyomatosis.

A 32-year-old Japanese housewife with a 2-year history of retroperitoneal and pulmonary lymphangiomyomatosis had a sudden onset of severe abdominal pain. Chest X-ray and plain abdominal films showed free air under the diaphragm and a small pneumothorax in the left lower pleural space. Emergency laparotomy revealed no perforated viscera, but there was a rupture in the mid-portion of the left diaphragm. It appears that increasing pressure in the left pneumothorax burst the left diaphragm leading to pneumoperitoneum.

Adult↗
PubMed1991

Formation of 6 beta-hydroxydexamethasone from dexamethasone by A6 cells.

A6 cells, a continuous cell line derived from kidney of Xenopus laevis, were incubated with [3H]-dexamethasone for 24 h. When radioactive compounds in media were separated by reversed phase high pressure liquid chromatography, two radioactive fractions were found. The less polar fraction which contained 91-93% of total radioactivity cochromatographed with dexamethasone, whereas the polar fraction contained 5% of total radioactivity in media. In order to rigorously identify the polar metabolite, large scale cultures were carried out and the polar compound was separated and purified by reversed phase high pressure liquid chromatography. The purified material was analyzed by secondary ion mass spectrometry and nuclear magnetic resonance spectroscopy. By these procedures, this material was identified as 6 beta-hydroxydexamethasone. To our knowledge these are the first data indicating that dexamethasone can be metabolized by transporting epithelia such as A6 cells.

Animals↗
PubMed1991

Effect of inhibition of oxygen free radical on ovulation and progesterone production by the in-vitro perfused rabbit ovary.

The potential role of oxygen free radicals in hCG-induced ovulation was investigated using the free radical scavenging enzymes superoxide dismutase (SOD) and/or catalase with the in-vitro perfused rabbit ovary preparation. SOD (25 micrograms/ml) and SOD + catalase (25 micrograms/ml) significantly reduced the % of large follicles that ovulated during perfusion (P less than 0.005). Neither maturity nor degeneration of ovulated ova and follicular oocytes was affected by SOD and/or catalase. Progesterone concentration in the perfusate was significantly increased in the SOD + catalase treatment group (P less than 0.01). These results indicate a significant role for oxygen free radicals in the process of ovulation.

Animals↗
PubMed1991

Direct effect of angiotensin II on in-vitro perfused rabbit ovary.

The effects of angiotensin II (AII) and its receptor blocker, saralasin (SAR), on ovulation and oocyte maturation were investigated in an isolated, in-vitro perfused rabbit ovary. Ovulation and oocyte maturation were induced by AII in the absence of human chorionic gonadotrophin (hCG). SAR inhibited ovulation induced by AII or hCG, but not oocyte maturation. AII appears to play a critical role in follicle rupture, but not in resumption of oocyte meiosis.

Angiotensin II↗
PubMed1991

Mechanical contraction property of the levator veli palatini muscle.

Twenty adult dogs anesthetized with sodium pentobarbital were used as experimental animals in an analysis of the mechanical contraction properties of the levator veli palatini muscle. The following results were obtained: the contraction time and half relaxation time of maximal isometric twitch of the muscle were revealed to be 43 msec and 33 msec, respectively; a summation curve was obtained with stimulation at 15 Hz and maximal tetanic tension was at 70 Hz. The average of the tetanic tension ratio was found to be 5.7. The maximum rate of tension rise was observed at 150 Hz, and the value was twice the rate of the twitch contraction. The duration time of the active state plateau showed values of 3.9 to 4.5 msec. The contraction time of the levator veli palatini muscle closely resembles that of the intrinsic laryngeal and the orbicularis oris muscle.

Animals↗
PubMed1991

Effect of a platelet activating factor antagonist and antithrombin III on septicemia and endotoxemia in rats.

Disseminated intravascular coagulation (DIC) or renal damage associated with septicemia was induced in rats by ligating the cecum or by injecting endotoxin. In the septicemia model, the number of E. coli and Bacteroides spp in the blood increased concomitantly with an increase of endotoxin. In this model the development of hypercoagulability with mild fibrinolysis was observed. Histopathologic findings in the kidneys, including the formation of microthrombi in the glomeruli and the vacuolization and dilatation of renal tubular cells, suggest the development of mild DIC. In the endotoxin-induced DIC model, both remarkable state of hypercoagulability and fibrinolysis were observed with fibrin thrombi in glomeruli. The administration of the platelet-activating factor antagonist, CV-6209, or of human antithrombin III, ameliorated DIC significantly by limiting the increases in prothrombin time, activated partial thromboplastin time and fibrin degradation products. These agents significantly reduced the deposition of fibrin in the glomeruli and significantly prolonged the survival time of the endotoxin injected rats. These observations suggest that the PAF antagonist CV-6209 and ATIII merit clinical evaluation in the management of DIC caused by septisemia.

Animals↗
PubMed1991

A case of lupus nephritis showing rectal erosion with cytomegalovirus infection.

A case of lupus nephritis showing rectal erosion with cytomegalovirus infection is described. The patient revealed nephrotic syndrome. She complained of skin ulcer with livedo reticularis on the right breast, purpura with thrombocytopenia, hepatic dysfunction, and bloody stool. Renal biopsy demonstrated diffuse proliferative lupus nephritis with prominent wire loops. Intestinal fiberscopy showed rectal erosion which was a cause of bloody stool, and rectal biopsy revealed cytomegalic inclusions characteristic of cytomegalovirus infection. Immunosuppression due to combined therapy with prednisolone and mizoribine could have led to reactivation of latent cytomegalovirus infection, resulting in the rectal erosion with bloody stool.

Adult↗