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Biomedical subjects

M Yamazaki

Publications and source records attributed to M Yamazaki.

At least 649 records · Page 36Linked to original sources
PubMed1990

[Tissue-type plasminogen activator and its inhibitor (PAI-1) in plasma in cases of non-insulin-dependent diabetes mellitus (NIDDM)].

Parameters of fibrinolysis, including plasminogen, alpha 2 plasmin-inhibitor (alpha 2 PI), tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) antigens, and fibrinogen were assayed in 53 patients (28 women and 27 men; mean age: 64 years, age range: 32-87 years) with non-insulin-dependent diabetes mellitus (NIDDM). The control group was similarly aged (mean age: 60.4 years, age range: 38-81). The levels of t-PA and t-PA/PAI-1 ratio of the diabetic group (mean +/- SD; 9.8 +/- 4.3 ng/ml, 0.94 +/- 0.47, respectively) were significantly higher than that of the control group (5.5 +/- 2.5 ng/ml, 0.51 +/- 0.23, respectively). The increased levels of t-PA antigen and t-PA/PAI-1 ratio in diabetics mean that free t-PA has been released. However, there was no significant difference in the level of PAI-1 between the diabetic group (12.9 +/- 6.4 ng/ml) and the control group (12.1 +/- 5.6 ng/ml). Levels of fibrinogen, plasminogen and alpha 2 PI in plasma were not different in the two groups. Duration of the disease, levels of glycosylated hemoglobin, differences in treatment and presense of diabetic nephropathy or retinopathy did not affect the fibrinolytic parameters. The levels of fibrinogen was higher in those with nephropathy than in the diabetics without nephropathy and retinopathy (p less than 0.05). There were no significant differences in the levels of t-PA, t-PA/PAI-1 ratio and PAI-1 between younger (less than 65 years) and older (65 years or more) subjects, in either the control or diabetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Molecular cloning of cDNA encoding a human heat-shock protein whose expression is induced by adenovirus type 12 E1A in HeLa cells.

We have identified by differential plaque hybridization, human cDNA clones encoding a member of a heat-shock protein family (hsp 90 alpha) in the cDNA library of Adenovirus Type 12 E1A transfected HeLa cells. The complete nucleotide sequence of one of the clones (pHB76-114A) was identified. The sequence of 2912 base pairs had a single reading frame with a coding potential for an 84,672-Da protein. The amino acid sequence was highly homologous, but not identical, to that of the human hsp 90 alpha gene isolated from human peripheral blood lymphocytes [M. Yamazaki, K. Akaogi, T. Miwa, T. Imai, E. Soeda and K. Yokoyama, Nucleic Acids Res., 17, 7108 1989)]. This cDNA hybridized with RNA species which increased 5- to 20-fold upon heat shock and more than 5-fold in the differentiation stage of human Tera 2 cells.

Adenoviruses, Human↗
PubMed1990

Effects of the new phosphodiesterase inhibitor griseolic acid on insulin release in rat pancreatic islets.

A new cyclic AMP phosphodiesterase inhibitor, griseolic acid (CAS 79030-08-3), in a dose-dependent manner increased insulin release and cyclic AMP level in rat pancreatic islets in the presence of 5.5 mmol/l glucose. Griseolic acid (0.26 mmol/l) or 3-isobutyl-1-methylxanthine (IBMX) (1 mmol/l) enhanced insulin release and cyclic AMP level both in the presence of 5.5 and 16.7 mmol/l glucose (no significant difference). In perifusion system, 45Ca++ efflux and insulin release showed a monophasic increase when the islets were exposed to 1.3 mmol/l griseolic acid or 1 mmol/l IBMX in the presence of 5.5 mmol/l glucose (no significant difference). In a cell-free system, griseolic acid had a stronger inhibitory effect on cyclic AMP phosphodiesterase activity than IBMX, has a stimulatory effect on insulin release through an increase of cyclic AMP by inhibiting phosphodiesterase in pancreatic islets, but it might not cross the plasma membrane easily.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Learning efficiency of a toothbrush for mastering scrubbing method.

Toothbrushing with long horizontal strokes often causes traumatization of sound enamel and gingival tissues. Also, dental plaque on cervical and adjacent surfaces of teeth can hardly be removed because toothbrush tips cannot reach these regions adequately. A toothbrushing device which indicates overstroke was tested to determine the efficacy with which it makes subjects master brushing with short horizontal strokes following an initial period of instruction. The degree of learning measured in the testing group was superior to that of the control group immediately after the first instruction. Moreover after one week and 12 weeks, its efficacy persisted. The plaque elimination ratio, however, showed no significant difference between the testing group and the control.

Adult↗
PubMed1990

[Study on prototype cylindrical HAP].

Hydroxyapatite (HAP) is currently utilized as biomaterials for implantation or reconstruction of bone defect in dentistry. In order to obtain better physical properties and biocompatibility, we have developed cylindrical sintered porous HAP which has longitudinal internal tubules. We measured compressive strength and specific surface area of cylindrical HAP. In the results, compressive strength was more 300MPa on average and specific surface area was 1.7-2.4 folds as HAP ceramics commercially available. This result indicates new bone formation. Cylindrical HAP used was subsequently applied to lower premolars and molars of male beagle dogs (1.5 years). We have implanted cylindrical HAP to bone defect of postextraction of tooth followed to sacrifice six months after. Specimens of bone block were stained with Villanueva bone stain and observed with fluorescence microscope and scanning electron microscope. New tissue formation was observed invading into tubules of 27 microns diameter of cylindrical HAP particles. This new tissue was confirmed to be bone tissue because the proportion of Ca to P was 1.616 obtained by energy dispersive X-ray analyzer.

Alveolar Bone Loss↗
PubMed1990

[A case of rigid spine syndrome with rimmed vacuole].

A case of rigid spine syndrome associated with rimmed vacuoles in muscle biopsy is reported. A 36-year-old man was admitted to our hospital because of gait disturbance and limited mortality of the spine. His family was free from any neuromuscular disorders. He was born in normal pregnancy and delivery. His physical development was normal. At age 7, he was unable to run fast. At age 36, he had right hemiparesis and dysarthria. He was diagnosed as cerebral infarction of the left basal ganglia by brain CT. Neurological examination revealed moderate proximal dominant muscular atrophy and weakness. His spine was straight, showing loss of physiological cervical and lumbar lordosis. The neck flexion was limited but the extension was full. And he had contracture of bilateral ankle joint. Laboratory findings were all normal. The electrocardiogram showed negative T wave in V4, V5 and QT interval elongation. The echocardiogram showed diffuse decrease of ventricular wall motion. Respiratory function test revealed decrease of vital capacity. Arterial blood gases on room air showed that the PaO2 and PaCO2 were 70 mmHg and 49 mmHg, respectively. The findings of electromyogram were compatible with myopathic change. Biopsy specimen of the biceps brachii muscle showed marked variation in fiber size, type 1 fiber predominancy and atrophy, and type 2B fiber deficiency. Numerous rimmed vaculoes were found in the same muscle. Four cases of the rigid spine syndrome with rimmed vacuoles have been described. Among them, three patients died in young ages and two suffered from constrictive respiratory failure. In rigid spine syndrome with rimmed vacuole formation, the cardiac and respiratory problems must be taken account intensively.

Adult↗
PubMed1990

[Effects of ketamine on voltage-dependent Ca2+ current in single smooth muscle cells from rabbit portal vein].

The effects of ketamine on membrane potentials and voltage-dependent Ca2+ current were studied in dispersed single smooth muscle cells from rabbit portal vein. The resting membrane potential (-56.2 +/- 1.5mV) was not affected by ketamine (10(-5)-10(-3)M). The duration and the amplitude of the action potential evoked by intracellular stimulation were significantly decreased by ketamine in the concentrations of 10(-4)M and 10(-3)M. Voltage-gated Ca2+ current in single smooth muscle cells was apparently decreased by ketamine at concentrations of between 10(-5)M to 10(-3)M. The activation threshold of Ca2+ current (approx. -30mV) was also decreased by ketamine. Therefore, these results suggest that inhibition of the contractile response by ketamine in vascular smooth muscle from rabbit portal vein may be attributable to the inhibition of the Ca2+ current.

Animals↗
PubMed1990

Purification and biochemical characterization of reno-ferredoxin from bovine kidney mitochondria.

Bovine reno-ferredoxin was purified from kidney mitochondria by an improved method that included hydrophobic and ion-exchange chromatography on Toyopearl gels. The optical absorption spectrum of the oxidized reno-ferredoxin revealed two peaks, at 414 and 455 nm in the visible region. The minimum molecular weight of the ferredoxin was 12,900 Da by SDS-polyacrylamide gel electrophoresis. The amino acid residues of the NH2-terminal sequence of the ferredoxin were investigated using by a gas-phase sequencer. Bovine reno-ferredoxin and adreno-ferredoxin showed almost identical NH2-terminal amino acid sequences. Reconstitution of the 25-hydroxyvitamin D3-1 alpha -hydroxylase system was performed with the following three components: NADPH-ferredoxin reductase from bovine kidney mitochondria, reno-ferredoxin, and cytochrome P-450(D1 alpha) from bovine kidney mitochondria. The results demonstrated that the reno-ferredoxin was essential for the 1 alpha-hydroxylase activity of 25-hydroxyvitamin D3.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1990

Purification and characterization of NADPH-ferredoxin reductase from bovine kidney mitochondria.

An NADPH-ferredoxin reductase (EC 1.6.7.1) was purified from bovine kidney mitochondria and its physicochemical properties were investigated. The ratio of the absorbances at 272 and 450 nm was 8.8, and the enzyme had a specific activity of 5,850 nmol/min/mg for the reduction of cytochrome c. We determined the molecular weights of the NADPH-ferredoxin reductase as 53,000 and 34,000 Da by SDS-PAGE and HPLC analysis, respectively. Renal ferredoxin was substituted by adreno-ferredoxin, but spinach ferredoxin was not. The reductase formed an immuno-precipitin line against antibody of the adrenal reductase on Ouchterlony double-diffusion analysis. The sequences of amino acid residues of this reductase in the amino-terminal regions were identical. The amino-terminal region of the reductase may thus play an essential role in the enzymatic function.

Adrenal Cortex↗
PubMed1990

[Queckenstedt test--pressure pattern analysis in spinal subarachnoidal block].

Pressure pattern analysis of Queckenstedt test was performed to detect the partial subarachnoidal block in patients with spinal or dural canal stenosis. The Queckenstedt test was performed by lumbar puncture when the patient was in lateral recumbent posture with bilateral jugular compression in three different neck positions; neutral, flexion and extension. Lumbar subarachnoidal pressure was visually measured each successive 5 seconds during a 30 second period of jugular compression, followed by a succession of 5 second measurements for 30 seconds after release of compression. The pressure changes during the total 60 seconds were demonstrated by pressure-time graph. The pressure pattern during jugular compression in patients with neurosis, neuropathy or muscle disease (total 18 cases, Fig.1) who were thought to have no subarachnoidal block showed sudden steep rise of pressure which gradually slowed and rapidly returned to pre-compression level after release of compression. The normal pattern showed upward convexity-downward concave and was almost identical in three different neck positions. Therefore we considered the normal pressure pattern to be a parabola-like or an exponential curve like patterns. The patients group with cevical spondylotic radiculopathy (16 cases, Fig. 3A) showed nearly normal pressure pattern except for some loss of upward convexity during neck extension and neutral positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

High-performance liquid chromatographic determination of secondary cardiac glycosides in Digitalis purpurea leaves.

An analytical method for the determination of secondary cardiac glycosides in Digitalis purpurea leaves by high-performance liquid chromatography (HPLC) is described. The procedure consisted of extraction of dry leaf powder with ethanol-chloroform (2:1) and clean-up by Sep-Pak cartridges prior to HPLC analysis. HPLC was performed on an octylsilyl bonded silica column, using acetonitrile-methanol-water (4:4:5) for trisdigitoxosides and acetonitrile-methanol-water (8:30:43) for strospeside; the effluent was monitored by ultraviolet detection (at 220 nm). Quantitation of these cardiac glycosides was carried out by the internal standard method. The amounts of digitoxin, gitoxin, gitaloxin and strospeside per 100 mg of dry leaf powder were estimated to be 22.6, 14.0, 54.7 and 1.9 micrograms, respectively. The method is sufficiently sensitive and reproducible to assay secondary glycosides in Digitalis purpurea leaves.

Chemical Phenomena↗
PubMed1989

Osmoelastic coupling in biological structures: formation of parallel bundles of actin filaments in a crystalline-like structure caused by osmotic stress.

A high molecular weight inert molecule, poly(ethylene glycol) (PEG), or a soluble protein, ovalbumin, causes parallel bundles of actin filaments in a crystalline-like structure under physiological conditions of ionic compositions and pH. The bundle formation depends on the molecular weight of PEG, and a larger molecular weight of PEG can make the bundle at a lower concentration. Actin bundle formation has a discrete dependence on the concentration of PEG. The light scattering following PEG-induced bundle formation increased abruptly at 4.5% (w/w) PEG 6000, while at concentrations less than or equal to 4.0% (w/w) no increase was observed. Labeling actin filaments with heavy meromyosin indicated that the polarity of the filament in the bundle is random. The PEG-induced bundle formation depends on the ionic strength of the solutions and also the concentration of the filament, showing that a higher concentration of PEG was required at lower ionic strength or a lower concentration of the filament. The results described above cannot be explained on the basis of the postulation that the direct binding of PEG molecules to the actin filaments may cause bundle formation. Alternatively, the mechanism can be explained reasonably by the theory of osmoelastic coupling based on preferential exclusion of PEG molecules from the filament surface. High molecular weight molecules such as PEG should be preferentially excluded from the region adjacent to the actin filaments (exclusion layer) by steric hindrance, thereby making imbalance of osmolarity between the bulk and the exclusion layer. This imbalance puts an osmotic stress on the actin filament.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1989

Isolation and characterization of a novel cytolytic factor in purple fluid of the sea hare, Aplysia kurodai.

A novel cytolytic factor, aplysianin P, which induces tumor lysis, was purified to apparent homogeneity from the purple fluid of the sea hare Aplysia kurodai. Purified aplysianin P was a single Mr 60,000 polypeptide. This factor was half-maximally active at 3-25 ng protein/ml and lysed all the tumor cells tested but did not lyse normal WBC or RBC. Aplysianin P was labile on treatments with heat, low pH, urea, and periodate, but not with Pronase. The factor completely inhibited the syntheses of DNA, RNA, and protein by tumor cells within 2 h and caused their complete cytolysis within 18 h. Tumor lysis by aplysianin P was inhibited by N-acetylneuraminic acid, suggesting that recognition of the sugar moiety is a key step in the cytolysis induced by aplysianin P. The factor also prolonged the survival of mice bearing syngeneic MM46 ascites. It did not resemble previously isolated antineoplastic glycoproteins from the eggs (aplysianin E) or albumen gland (aplysianin A) of A. kurodai in terms of molecular size, antigenicity, or amino acid composition. These results suggest that aplysianin P found in an invertebrate, the sea hare, is a new antitumor factor.

Amino Acids↗