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Biomedical subjects

K Okazaki

Publications and source records attributed to K Okazaki.

At least 253 records · Page 14Linked to original sources
PubMed1994

Direct evidence for erythropoietin-induced release of endothelin from peripheral vascular tissue.

The effect of recombinant human erythropoietin (r-HuEPO, 0.1 to 2.0 U/ml) on endothelin-1 (ET-1) release was examined in isolated hind legs perfused with Krebs-Ringer solution from normal rats. r-HuEPO increased immunoreactive (ir-) ET-1 release in a dose-dependent fashion; the maximal percent increment in ir-ET-1 release evoked by r-HuEPO (2.0 U/ml) was about +210% over the basal rate of release. However, r-HuEPO showed no effect on release of angiotensin II, thromboxane B2 or vasodilatory prostaglandin I2 from the vasculature. These results not only provide direct evidence that r-HuEPO has the potential to specifically stimulate release of ET-1 from peripheral vascular beds, but, hence, suggest a contributory role of ET-1 in r-HuEPO-induced hypertension in anemic human subjects undergoing r-HuEPO therapy.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Properties of titanium dental implants produced by electro-discharge compaction.

Highly porous dental implants of a cylindrical shape were fabricated from commercial grade titanium REP-atomized powders by EDC. They were intended to have the maximum porosity for maximum osseointegration, but to maintain the minimum mechanical properties functionally required. Two level full factorial experiments were conducted with respect to the sample weight, capacitance, input energy and electrode configuration. All samples were X-rayed prior to tests to ascertain the presence, extent and distribution of internal macroscopic voids. Torque and compression tests were conducted to evaluate the yield or ultimate strengths (34-90 cm N and 205-502 MPa, respectively). These results indicate that macroscopic void-free, highly porous implants can be fabricated.

Dental Implants↗
PubMed1994

Quantitative evaluations of male pattern baldness.

Several methods for the evaluation of hair growth have been reported; however, none of the hitherto reported methods are satisfactory as unbiased double blind studies to evaluate the efficacy of hair growth agents. In the present paper, we describe quantitative evaluation methods for hair growth by measuring the anagen ratio and hair diameters in 56 Japanese subjects aged 23-56 for 3 years. The average anagen ratio decreased by 3.8% in 3 years. The average hair diameters showed a statistically significant decrease each year totalling 3.4 microns. Subjects were sorted according to their anagen ratio into 4 groups. Each group showed different distribution patterns of hair diameters. The higher anagen ratio group has a high frequency peak at thicker hair diameters and the lower anagen ratio group has a high frequency peak at thinner hair diameters. The number of thicker hairs decreased and the high frequency peak shifted to thinner hair diameters in 3 years. These methods are useful to evaluate both the progression of male pattern baldness and the effects of hair growth agents with double blind studies in an unbiased quantitative fashion.

Adult↗
PubMed1994

Identification of autoantibodies to a pancreatic antigen in patients with idiopathic chronic pancreatitis and Sjögren's syndrome.

A serum autoantibody to a pancreatic antigen was identified in patients with idiopathic chronic pancreatitis and Sjögren's syndrome by radioimmunoassay and Western immunoblotting. Antigen from porcine and human pancreas extracts was partially purified using a monoclonal antibody, SP3-1, which recognizes the antigen in duct cells of various exocrine organs. Solid phase radioimmunoassay of the pancreatic antigen showed a positive result in 6 of 20 patients with idiopathic chronic pancreatitis (30%), 3 of 11 patients with Sjögren's syndrome (27%), and 1 of 15 patients with alcoholic chronic pancreatitis (7%). Among seven patients with stone-related chronic pancreatitis, six patients with autoimmune thyroiditis, and 14 normal controls, none showed evidence of autoantibodies to the pancreatic antigen. Western immunoblotting showed that serum antibody commonly reacted with a 60-kD molecule of either porcine or human pancreatic antigen, with which SP3-1 also reacted. These results show the existence of the autoantibodies to pancreas, especially to an antigen expressed in ductal cells of exocrine glands, in idiopathic chronic pancreatitis and Sjögren's syndrome, and suggest the possibility of an autoimmune mechanism in the pathogenesis of idiopathic chronic pancreatitis.

Animals↗
PubMed1994

Expression of bovine herpesvirus 1 glycoprotein gIII by a recombinant baculovirus in insect cells.

Bovine herpesvirus 1 (BHV-1) glycoprotein gIII functions both as a major virus attachment protein and haemagglutinating protein. Here we constructed recombinant baculovirus incorporating the BHV-1 gIII coding sequence to characterize the expression, function and immunogenicity of the glycoprotein in insect cells. The recombinant gIII had an M(r) of 72K and seemed to form homodimers. The gIII was expressed on the surface of insect cells and a rosette formation assay demonstrated haemadsorbing activity of the glycoprotein. Antigenic authenticity of the recombinant gIII was confirmed by a panel of monoclonal antibodies specific for the glycoprotein produced in mammalian cells. Antisera raised to recombinant gIII neutralized the infectivity of BHV-1. These data suggest that recombinant gIII produced in insect cells may be a useful immunogen in a BHV-1 vaccine.

Animals↗
PubMed1994

Detection of specific systemic and local IgG and IgA antibodies of pigs after infection with Bordetella bronchiseptica by ELISA.

An enzyme linked immunosorbent assay (ELISA) for detection of IgG and IgA antibodies against Bordetella bronchiseptica in serum and nasal secretions of pigs was developed. The ELISA that used formolized phase I organisms of B. bronchiseptica as an antigen detected antibodies to a capsular K antigen(s) of the organism. In pigs which had an agglutinin titer of less than 10 and an ELISA value of 0.47, on average, of maternal antibodies to B. bronchiseptica, IgG antibody in serum increased 4 weeks on average and IgG and IgA antibodies in nasal secretions rose markedly 1 and 2 weeks, respectively, after appearance of more than 5 x 10(3) colony forming units per ml of the organisms in the nasal cavity. In contrast, IgG antibody response in serum was inhibited strongly and no increase of the antibody was observed in pigs that had high titers (an agglutinin titer of 149 and an ELISA value of 1.49, on average) of the maternal antibody. In the pigs, a typical decrease in the production and marked delay in the time course of the production of IgG and IgA antibodies in the nasal cavity were also observed. Thus, although pigs produced systemic and local antibodies to B. bronchiseptica, the antibody response was affected dose responsively by the maternal antibody. However, the effect seemed to be a little milder in local antibody responses than in systemic antibody responses. The role of the local antibodies in eradication of the organism in the nasal cavity was not elucidated.

Animals↗
PubMed1994

Immune complex specific for the pancreatic duct antigen in patients with idiopathic chronic pancreatitis and Sjögren syndrome.

Circulating immune complexes (ICs) containing the pancreatic antigen against SP3-1 monoclonal antibody were measured in patients with idiopathic chronic pancreatitis (ICP) and Sjögren syndrome (SjS) by Raji cell and solid-phase radioimmuno-assays (RIA). The mean serum levels of ICs measured by solid-phase RIA were significantly higher in patients with ICP (n = 23) and SjS (n = 21) than control (n = 15, p < 0.05, p < 0.02, respectively). ICs were positive in 10 patients with ICP (43%) and 12 SjS patients (57%). Raji cell assay also revealed a significantly higher serum ICs levels in patients with ICP (n = 17) and SjS (n = 12) compared with those of control (n = 7, p < 0.025, p < 0.005, respectively). Seven patients with ICP (41%) and 8 SjS patients (67%) had positive ICs. This was in contrast to the normal level of ICs in patients with alcoholic chronic pancreatitis, primary biliary cirrhosis, and chronic thyroiditis. Our analysis demonstrated a significant and positive relationship between RIA and Raji cell assay (r = 0.70, p < 0.05). Our results suggest that ICs specific for SP3-1 may play a role in the pathophysiology of ICP and SjS.

Alcoholism↗
PubMed1994

An evaluation of electrodischarged prototype implants in rabbit tibia: a preliminary study.

This is the first in a series of biological investigations using a porous implant fabricated by a novel process known as electrodischarge compaction (EDC). This process uses Ti-6A1-4V powder and electrical energy to construct a beaded porous implant without any compromise in physical characteristics, often found with conventional sintering. The purpose of this study was to evaluate the bone response in rabbit tibia of a porous titanium prototype implant fabricated by this new technique. One hundred forty-four porous EDC-fabricated implants were placed into the tibia of 36 New Zealand rabbits. Animals were placed into one of six time periods (2, 4, 8, 12, 18, and 24 weeks). At the appropriate time period, animals were killed, and bone ingrowth was evaluated qualitatively by light and scanning electron microscopy. Bone/implant interface bond strength was also measured. Slight bone ingrowth was observed as early as the two-week time period and increased in depth at each time period for the duration of the study. Implant/bone bond strength was measurable at four weeks and continued until reaching a plateau at week 12. The results of this study suggest that this novel EDC implant may be suitable for continued development of an easily fabricated, cost-effective dental implant.

Aluminum↗
PubMed1994

KN-62, a specific Ca++/calmodulin-dependent protein kinase inhibitor, reversibly depresses the rate of beating of cultured fetal mouse cardiac myocytes.

Effects of KN-62 (1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4- phenylpiperazine), a specific Ca++/calmodulin (CaM)-dependent protein kinase inhibitor, were examined on the rate of spontaneous beating and the intracellular Ca++ transient of cultured myocytes from fetal mouse ventricle. KN-62 depressed the rate of beating in a dose-dependent fashion. Spontaneous beating ceased 10 min after the administration of 1 microM KN-62 and recovered gradually after washing with cultured medium. Addition of KN-04 [N-(1-1[P-(5-isoquinolinsulfonyl)benzyl]-2-(4- phenylpiperazinyl)ethyl)-5-isoquinolinsulfonamide; 1 microM], an analog of KN-62, did not change the rate of beating. In the experiment using an intracellular Ca++ fluorescence indicator, fluo-3, KN-62 depressed the fluo-3 intensity at a systolic phase. The kinase activity to syntide-2 of Ca++/CaM kinase II purified from the rabbit heart was inhibited by KN-62, but not by KN-04. Addition of KN-62 inhibited the phosphorylation of phospholamban by Ca++/CaM kinase II in a dose-dependent manner. KN-62 depressed the Ca(++)-pumping ATPase activity in the presence of Ca++ and CaM by 32%. These findings indicate that Ca++/CaM kinase II changes an intracellular Ca++ transient and modulates the rate of beating at least in part.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1994

Strain difference in establishment of mouse embryonic stem (ES) cell lines.

For utilization of the mouse embryonic stem (ES) cells for various purposes, it is desirable that the cell lines are established from various sources such as inbred and mutant mouse strains. So far, however, most ES cell lines used in genetic manipulation have been derived from the 129/Sv strain. We have established ES cell lines from blastocysts of the C57BL/6 strain at high efficiency by use of a fibroblast cell line SL10 as feeder cells, and supplementing the culture medium with 5,000 unit/ml LIF. Using such culture conditions, we have also established a number of ES cell lines from the BALB/c, BXSB/MpJ-Yaa and MRL/Mp-lpr/lpr mouse strains. Procedure for establishment of ES cell lines had to be modified among the mouse strains, indicating the strain difference. For example, only a few stem cell colonies appeared from the BALB/c blastocysts. Stem cells of the BXSB strain were very sensitive to the trypsinization in subculturing. Most of these cell lines had normal karyotype and produced chimeric mice. Several C57BL/6 cell lines contributed to the germ-line. These results indicate that ES cell lines can be established from various mouse strains, but their characteristics are different among strains.

Animals↗
PubMed1994

[Myocardial metabolism, oxygen demand and oxygen supply during prostaglandin E1 induced hypotension].

The effects of hypotensive anesthesia induced by PGE1 on myocardial metabolism, oxygen demand and oxygen supply were studied. Nine mongrel dogs were anesthetized with pentobarbital and isoflurane. Mean blood pressure (MBP), cardiac output (CO), blood gases (BG), coronary blood flow (CBF), and myocardial tissue oxygen tension (MPO) were measured. Arterial and coronary venous lactate and pyruvate concentrations were also measured. We calculated myocardial oxygen consumption, L/P ratio, excess lactate, oxygen extraction ratio and lactate extraction ratio to estimate the adequacy of myocardial aerobic metabolism. CO and CBF decreased in accordance with MBP depression. Myocardial oxygen consumption decreased significantly with PGE1 administration. Lactate and pyruvate concentrations, L/P ratio, excess lactate and myocardial tissue oxygen tension were unchanged. These results suggest that PGE1 exerts no significant effect on myocardial metabolism during hypotensive anesthesia.

Alprostadil↗
PubMed1994

[The effects of adenosine-induced hypotension on myocardial metabolism].

The effects of hypotension induced by adenosine on myocardial metabolism were studied in ten mongrel dogs anesthetized with 0.5% isoflurane. Adenosine was infused intravenously to reduce mean arterial blood pressure by approximately 30% during a period of 20 min. Although heart rate was unchanged, cardiac output increased and coronary blood flow increased 3-fold of the preinfusion value. Oxygen tension of the myocardium, and oxygen extraction as well as lactate extraction of the myocardium decreased. Myocardial oxygen uptake and myocardial lactate uptake were unchanged, but lactate production was observed in three of ten dogs. In addition, coronary venous lactate/pyruvate ratio and excess lactate increased, and excess lactate became positive in five of ten dogs. The results suggest that adenosine-induced hypotension may inhibit the myocardial aerobic metabolism.

Adenosine↗
PubMed1994

[Effect of 10% carbon dioxide on regional myocardial tissue oxygen tension and myocardial metabolism].

We investigated the effects of arterial carbon dioxide tension on myocardial blood flow, tissue oxygen tension and metabolism in the anesthetized dogs. Eighteen adult mongrel dogs weighing 13.4 +/- 3.6 kg were anesthetized with 0.5% isoflurane, intubated and ventilated mechanically with 50% oxygen to maintain normocapnia. Endtidal CO2 fraction (FECO2) was monitored continuously by capnograph. Regional myocardial tissue PO2 was measured using a monopolar polarographic needle electrode inserted to the myocardium. Electromagnetic blood flow probes were applied on the left anterior descending artery and circumflex artery. For cardiac venous blood sampling, a 23G intravenous catheter was inserted into the cardiac veins (great coronary veins) carefully. After normocapnic ventilation, hypocapnia was induced by increasing the respiratory rate, and hypercapnia was induced by adding 10% carbon dioxide to the inspired gas. The coronary blood flow and myocardial tissue oxygen tension increased during hypercapnia and the myocardial lactate extraction decreased, while excess lactate and cardiac venous L/P ratio increased during hypercapnia. These results indicate that hypercapnia increase coronary flow and myocardial tissue oxygen tension but myocardial aerobic metabolism is impaired during hypercapnia.

Anesthesia, Inhalation↗
PubMed1993

Neurocalcin immunoreactivity in rat olfactory bulb.

Neurocalcin, a newly discovered calcium-binding protein belonging to the recoverin-like superfamily, was detected immunohistochemically in tufted cells from the rat olfactory bulb. More precisely, only periglomerular tufted cells and some tufted cells from the external plexiform layer were expressing neurocalcin. Western blot analysis has confirmed the presence of neurocalcin in rat olfactory bulb. Lack of neurocalcin immunoreactivity in mitral cells and periglomerular cells favor a different phylogenic origin between tufted and mitral or periglomerular cells.

Animals↗
PubMed1993

Mos is degraded by the 26S proteasome in a ubiquitin-dependent fashion.

Mos, the c-mos proto-oncogene product, is a key regulator of cell cycle progression. Recently, rapid turnover of Mos in an early stage of meiotic maturation of Xenopus oocytes was found to be mediated by the ubiquitin pathway, but the protease responsible for its breakdown was not identified. In the present study, we found that 35S-labeled Mos synthesized in an in vitro transcription/translation system was degraded ATP- and time-dependently by the 26S proteasome, but not by the 20S proteasome, in the presence of a ubiquitin-ligation system. The 26S proteasome did not degrade a mutant Mos in which Ser3 was replaced by Asp3 that is metabolically stable in oocytes, indicating a similarity in the proteolytic events in vivo to those observed in vitro in the present work. This is the first demonstration that the proteasome catalyzes the ATP-dependent degradation of a naturally occurring, short-lived oncoprotein by the ubiquitin pathway. This finding suggests that the proteasome may regulate the intracellular stability of various oncoproteins.

Adenosine Triphosphate↗