Biomedical subjects

Y Ozaki

Publications and source records attributed to Y Ozaki.

At least 19 recordsLinked to original sources

PubMed1992

[Adverse reactions to low osmolar iodine contrast media (second report)].

From January to December 1990, we performed a prospective survey of adverse reactions to contrast media at two different institutes of Juntendo University. We collected a total of 4555 case sheets during the period. The radiological procedures we investigated were computed tomography, intravenous urography, arteriography, venography and myelography. Low osmolar iodine contrast medium was used almost exclusively (except for five cases). The overall incidence of adverse reactions was 7.0%, and there were no severe or fatal reactions. The incidence of adverse reactions was higher in females (8.5%) than in males (6.1%). The incidence of adverse reactions increased according to the dose of contrast medium, especially when more than 101 ml was injected. Intra-arterial injection caused adverse reactions most often, followed by regular intravenous injections, followed by bolus intravenous injections. Adverse reactions occurred most often during injection. The next occurred in 5 minutes after injection, and then, 5-10 minutes after the injection of contrast medium. The incidence of adverse reactions was higher in patients with a history of allergy or previous reactions. Allergic adverse reactions were observed at a higher frequency. Pretesting was performed in 56.7% of the cases.

Adolescent↗

PubMed1992

Effects of oral hypoglycaemic agents on platelet functions.

The in vitro effects of three oral hypoglycaemic agents, gliclazide (1-(4-methylbenzensulfonyl)-3-[3-azabicylo(3,3,0)octyl]urea) , glibenclamide (1-[4-[2-(chloro-2-methoxybenzamide)-ethyl]-phenyl- sulfonyl]-3-cyclohexyl-urea) and glimepiride (1-[4-[2-(3-ethyl-4-methyl-2-oxo-3-pyrroline-carboxamide)- ethyl]-phenylsulphonyl]3-(4-methylcyclohexyl)-urea), on functions of human platelets were evaluated. None of these agents up to a concentration of 40 microM inhibited platelet aggregation induced by thrombin. Glibenclamide and glimepiride in the range of 20-40 microM suppressed Ca2+ release from internal Ca2+ stores induced by thrombin. Gliclazide showed no effect on arachidonic acid metabolism of human platelets. Glimepiride selectively inhibited the cyclooxygenase pathway, while the activities of 12-lipoxygenase and phospholipase A2 were unaffected. Glibenclamide inhibited both the cyclooxygenase and 12-lipoxygenase pathways. It also attenuated arachidonic acid release from phospholipase A2. Oral hypoglycaemic agents with inhibitory effects on arachidonic acid metabolism may prove useful for the treatment of diabetic patients with enhanced platelet functions.

Arachidonic Acid↗

PubMed1992

Synthesis of phosphatidylinositol 3,4-bisphosphate but not phosphatidylinositol 3,4,5-trisphosphate is closely correlated with protein-tyrosine phosphorylation in thrombin-activated human platelets.

Synthesis of D-3-phosphorylated phosphoinositides and its correlation with protein-tyrosine phosphorylation were examined using human platelets. Thrombin stimulation of platelets resulted in time- and dose-dependent production of phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2), which is absent from resting platelets. In contrast, phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) was detected in resting platelets, but remained unaffected by thrombin treatment. The production of PtdIns(3,4)P2 but not PtdIns(3,4,5)P3 was inhibited by pretreatment with staurosporine or dibutyryl cyclic adenosine monophosphate (dbcAMP). Protein-tyrosine phosphorylation, which is reportedly involved in generation of 3-phosphorylated phosphoinositides, was elicited in thrombin-activated platelets. The tyrosine phosphorylation was suppressed by pretreatment with staurosporine or dbcAMP. These observations suggest that synthesis of PtdIns(3,4)P2 but not PtdIns(3,4,5) P3 is closely correlated with protein-tyrosine phosphorylation in human platelets.

Alkaloids↗

PubMed1992

Near-infrared FT-Raman spectra of the rat brain tissues.

Near-infrared Fourier transform (FT) Raman spectroscopy was applied to brain tissues in situ. The spectra were obtained from the cerebral cortex, white matter of the cerebrum, caudate-putamen, thalamus, synaptosomal fraction, and myelin fraction. High-quality Raman spectra in the 400 to 2940 cm-1 range were measured without interference of autofluorescence. Common spectral bands were assigned. The ratios of the intensity at 1664 (amide I), 1442 (CH2 deformation), 2885 (CH2 asymmetric stretching), 2938 cm-1 (CH3 symmetric stretching) could be used for differentiation between the gray and white matters.

Animals↗

PubMed1992

Molecular aging of lens crystallins and the life expectancy of the animal. Age-related protein structural changes studied in situ by Raman spectroscopy.

In order to investigate the relationship of molecular aging of lens crystallins to an animal's life expectancy or to the type of the lens, Raman spectra have been measured in situ for rabbit and guinea-pig lens nuclei at various stages of aging; these spectra have been compared with those of rat and mouse lens nuclei previously reported. Lens aging results in pronounced differences among the Raman spectra of the lens nuclei of the four species. It is shown that the rates of dehydration, inter- and intramolecular disulfide bond formation, and microenvironmental changes in the tryptophan residues of lens crystallins are different among the four species. Much faster changes occur for rat and mouse, which have a shorter life expectancy (2 years) and give rise to hard lens nuclei while slower changes occur for rabbit and guinea-pig, which have a longer life expectancy (5-7 years), and give soft lens nuclei. In addition, the Raman data reveal, for all the species investigated, that there are correlations among the rates of the dehydration, the inter- and intramolecular disulfide bond formation, and the microenvironmental changes in the tryptophan residues. Therefore, there seems to be a common mechanism for molecular aging of lens crystallins among the four species, although the rate of the molecular aging strongly depends upon the life expectancy of the animal and the type of the lens. The most important factor determining the rate of the molecular aging is probably the dehydration which decreases free water in the lens nucleus.

Aging↗

PubMed1992

Selective inhibition of membrane fusion events in echinoderm gametes and embryos by halenaquinol sulfate.

Halenaquinol sulfate, a hydroquinone sulfate obtained from the sponge Xestospongia sapra, prevented cell membrane fusion events of echinaderm gametes but did not affect early embryonic development of fertilized eggs up to the gastrula stage. However, halenaquinol sulfate inhibited secretion of hatching enzyme, resulting in the formation of gastrulae that were surrounded by the fertilization envelope. Therefore, the use of halenaquinol sulfate offers a unique opportunity to analyze the role of secretory events in complex populations of cells without affecting other cellular functions.

Animals↗

PubMed1992

Thrombin-induced calcium oscillation in human platelets and MEG-01, a megakaryoblastic leukemia cell line.

Digital imaging microscopy revealed that human platelets show periodic intracellular Ca++ elevation in response to 0.01 U/ml thrombin. MEG-01, a megakaryoblastic leukemia cell line, also responded with oscillatory intracellular Ca++ elevation (0.7-1 times/min) to thrombin (0.001-0.003U/ml). Ca++ transients appears to be fused with higher thrombin doses. With extracellular Ca++ concentrations of 0.1 mM or less, Ca++ oscillation could not be elicited, or even when present, it disappeared after a few spikings of [Ca++]i. Extracellular Ca++ concentrations of 0.3 mM or more were required to facilitate ongoing Ca++ oscillation, suggesting an important role of Ca++ influx for Ca++ oscillation.

Blood Platelets↗

PubMed1992

Anti-platelet action of isoliquiritigenin, an aldose reductase inhibitor in licorice.

The mechanism was studied by which isoliquiritigenin, a new aldose reductase inhibitor purified from licorice (Glycyrrhizae radix), inhibits platelet aggregation. This new agent significantly inhibited the phosphorylation of 40,000- and 20,000-dalton proteins, and inhibited the formation of 12 (S)-hydroxy-5,8,10-heptadecatrienoic acid, 12-hydroxyeicosatetraenoic acid and thromboxane B2. The inhibitory effect of isoliquiritigenin on platelet aggregation in vitro was comparable to that of aspirin. Our findings may indicate that isoliquiritigenin elicits an anti-platelet action by inhibiting not only cyclooxygenase but also lipoxygenase or peroxidase activity in platelets. Isoliquiritigenin also showed an anti-platelet action in vivo. Isoliquiritigenin appears to be the only aldose reductase inhibitor with a significant anti-platelet action. Since the hyperaggregability of platelets has been implicated in the pathogenesis of diabetic complications, isoliquiritigenin may offer a unique benefit as an aldose reductase inhibitor.

Aldehyde Reductase↗

PubMed1992

Re-appraisal of clinical usefulness of 67Ga-citrate scintigraphy for primary colorectal carcinoma: with evaluation of scintigram obtained from resected specimens.

Clinical usefulness of 67Ga-citrate scintigraphy for the diagnosis of colorectal carcinoma was reappraised at the standpoint of clinicopathological diagnosis. Fifty-eight patients with colonic carcinoma were subjected to this study. They underwent 67Ga scintigraphy before surgery. Colorectal carcinomas were detected in 38 patients, 65.5% by this procedure. Surgical specimens from thirty-seven patients underwent postoperative scanning. The scanning of the surgical specimen revealed accumulation of 67Ga-citrate in all 37 patients, suggesting that 67Ga-citrate accumulated in the carcinoma of the colon. The results suggested that detectability of carcinoma of the colon by 67Ga scintigraphy in this series was better than generally considered. 67Ga scintigraphy was considered to provide useful information in cases of severe stenosis and dolichocolon which were difficult to diagnose with a Barium enema and fiberscope. The problem is that abnormal accumulation is sometimes hard to distinguish from physiological excretion in the stools. However we believe that images should be carefully evaluated, keeping in mind the fact that 67Ga-citrate could accumulate in a colorectal carcinoma, and also believe that we radiologists should actively promote Ba-enema examination in positive cases rather than to devote time to the differentiation between physiological excretion of 67Ga in the stools and accumulation in a colorectal carcinoma.

Adenocarcinoma↗

PubMed1992

Long-term study of recurrent vasospastic angina using coronary angiograms during ergonovine provocation tests.

Chronologic changes of coronary spasm were examined by repeated ergonovine provocation tests during angiography. A total of 322 patients who had variant angina without severe atherosclerosis demonstrated a positive response to the first test. Ninety of these patients had recurrent variant anginal symptoms after an angina-free period of 38 +/- 12 months (mean +/- SD). Of these 90 patients, 76 (84%) had symptoms or electrocardiographic (ECG) findings similar to those of the first test. The initial 9 of these 76 patients underwent a second provocation test and showed coronary responses analogous to those on the first test. Of the 90 patients, 14 (16%) had different symptoms or ECG findings from those elicited at the first episode. All 14 patients again had a positive response to a second ergonovine test and the following angiographic changes were observed in the three major vessels between the two tests. Of the 21 vessels that had spasm on the first test, eight vessels (19%) did not have spasm on the second test. Of the 21 vessels that did not demonstrate spasm on the first test, 10 (24%) demonstrated spasm on the second test. In the present study it is concluded that the majority of patients with recurrent angina seemed to have consistency in the location of coronary spasm, while in some patients the fluctuation of coronary spasm was confirmed by two ergonovine provocation tests.

Adult↗

PubMed1992

Evaluation of platelet calcium ion mobilization by the use of various divalent ions.

Divalent ion mobilization in human platelets was evaluated with Fura-2 fluorescence changes induced by Ca2+, Sr2+, Ba2+ and Mn2+. Extracellular Ca2+, Sr2+ and Ba2+ all entered thrombin-stimulated platelets. These divalent ions were also able to refill the intracellular Ca2+ storage sites which had been depleted of Ca2+ by ionomycin treatment, and were released from the storage sites upon thrombin stimulation. However, only the refilling of the storage sites with Ca2+ and Sr2+, but not with Ba2+, were capable of suppressing the opening state of Ca2+ channels assessed with Mn2+ influx. Efflux of intracellularly accumulated divalent ions was observed with Ca2+ and Sr2+ but not with Ba2+. These findings indicate that there are subtle differences in the Ca(2+)-binding domains of the various systems involved in Ca2+ mobilization in platelets, some of which discriminate Ba2+ while accepting Sr2+.

Barium↗

PubMed1992

Antiinflammatory effect of tetramethylpyrazine and ferulic acid.

Tetramethylpyrazine (TMP) is one of the alkaloids contained in Ligusticum wallichii Franch (L. wallichii). Ferulic acid (FA) is a phenolic compound contained in L. wallichii and Angelica sinensis (Oliv.) Diels (A. sinensis). The present study was carried out to examine the antiinflammatory effect and to elucidate the mode of the effect of TMP and FA. Both compounds significantly inhibited the edema induced by carrageenin, the increase of the dye leakage induced by acetic acid and the granuloma formation induced by cotton pellet. And also, TMP and FA inhibited the number of writhes induced by acetic acid. From these results, it is suggested that both compounds have the antiinflammatory effect and the analgesic effect, and both compounds exert an antiinflammatory effect at the early and the late stages of processes in the inflammatory pathology.

Animals↗

PubMed1992

[Limonoids in Phellodendron amurense (Kihada)].

Limonoids and their glucosides in the seeds and barks of Phellondendron amurense (Kihada) were analyzed. The seeds contained limonin (1950 ppm), obakunone (20 ppm), limonin 17-beta-D-glucopyranoside (820 ppm) and obakunone 17-beta-D-glucopyranoside (1360 ppm). The barks contained limonin (6760 ppm), obakunone (1240 ppm) and nomilin (270 ppm).

Chromatography, High Pressure Liquid↗

PubMed1992

Estimation of structural changes in the cataractous rat lens using Raman spectroscopy.

For quantitative evaluation of cataract-related changes in lens proteins and lens water, the relative contents of water and SH residues and changes in the microenvironments of aromatic amino acid residues were quantitatively examined in cataract of the rat lens which had been induced by sodium selenite. Using Raman spectroscopy, results were compared with those of age-matched control lenses. The relative contents of water and SH residues decreased with increasing age in normal lenses from 3 to 8 weeks of age. In the cataractous lens, the relative water content increased constantly as compared with that of age-matched controls. The relative SH residue content continued to decline in the cataractous lenses of animals at every age. The microenvironments of tyrosine residues in cataractous lenses also changed progressively.

Animals↗

PubMed1992

Distribution of natural killer cells in periodontal diseases: an immunohistochemical study.

We studied the distribution and incidence of natural killer (NK) cells in gingiva affected with adult periodontitis (AP) and rapidly progressive periodontitis (RP) with immunohistochemical methods using antibodies Leu-7 and Leu-11b. The incidence of Leu-7 positive cells revealed no significant difference among mild AP, severe AP, and RP. On the other hand, Leu-11b positive cells were frequently found in severe AP and RP. The accumulation of NK cells reacting with Leu-11b in the infiltrated connective tissue was greater in severe forms of periodontal disease (severe AP and RP) than in mild AP. These results suggest that Leu-11b positive NK cells may play a role in the destruction of tissues in periodontal diseases.

Adult↗

PubMed1992

[Prophylactic intravesical instillation therapy in patients with superficial bladder cancer--results of a randomized prospective study].

A randomized prospective study was conducted for the purpose of investigating the efficacy of intravesical chemoprophylaxis of superficial bladder cancers. Eligible patients were randomized into three groups: 1) adriamycin (ADM) group; intravesical instillation with 50 mg of ADM dissolved in 100 ml physiological saline, 2) mitomycin C (MMC) group; intravesical instillation with 30 mg of MMC dissolved in 100 ml of physiological saline, 3) control group; transurethral resection or transurethral coagulation only. The characteristic features of our protocol consisted of frequent (six times) instillations of the drugs within two weeks after transurethral resection, followed by instillations on two consecutive days at four-week intervals for two years. Furthermore, large quantities (100 ml) of instillation fluid containing relatively low concentrations of the drugs (500 micrograms/ml for ADM or 300 micrograms/ml for MMC) were employed. One hundred and forty-four patients have been submitted to the study; 110 patients were fully evaluable for recurrence and 34 patients were eliminated as non-evaluable patients. The cumulative five-year non-recurrence rates of the patients with multiple tumors were 32% in the MMC group, 25% in the ADM group and 7% in the control group. The cumulative non-recurrence rates of the ADM and MMC groups were significantly higher than that of the control group. It is considered that this instillation therapy with ADM and MMC is useful for preventing the recurrence of superficial bladder cancers.

Administration, Intravesical↗

PubMed1992

[Effect of pH on blood cells].

Intracellular pH of blood cells is controlled by the Na+/H+ exchanger and anion channels. The Na+/H+ exchanger plays a major role in elevating intracellular pH in activated platelets, lymphocytes and neutrophils. In lymphocytes, intracellular alkalinization is associated with proliferation and differentiation. In platelets, protein kinase appears to increase the turnover rate of Na+/H+ exchange, thus accelerating the process of alkalinization. Intracellular alkalinization serves to increase the energy supply by glycolysis, and to activate the production of thromboxane A2, a potent activator of platelets. Clinically an increased activity of the Na+/H+ exchanger has been demonstrated with platelets from hypertensive patients.

Acid-Base Equilibrium↗

PubMed1992

[81mKr scintigraphic evaluation of hemodynamics in gynecologic malignancies under condition of angiotensin II-induced hypertension].

Transcatheter arterial infusion chemotherapy is one of the most useful therapeutic procedures for gynecologic malignancies. Recently, several reports have been published about Angiotensin II-induced hypertension chemotherapy and the efficacy of the method, but there have been no reports to evaluate an application for gynecologic malignancies. We evaluate the usefulness of the method for gynecologic malignancies demonstrating the changes of hemodynamics of the tumor using 81mKr scintigraphy. Thirteen patients with pathologically confirmed gynecologic malignancies were evaluated by angiography and continuous infusion of 81mKr via the catheter with and without Angiotensin II. At first, continuous infusion of 81mKr was performed under the superselective catheterization of the uterine artery. The radioactivities in the ROI were counted. Then, withdrew the catheter from the uterine artery to the internal iliac artery, and again continuously infused 81mKr and counted the radioactivities in the same ROI. Finally, keeping the catheter in the internal iliac artery, Angiotensin II and 81mKr were infused simultaneously. And counted the radioactivities. The radioactivities were highest when the catheter tip was placed in uterine arteries and lowest when the catheter tip was placed in internal iliac arteries. But radioactivities in the ROIs were definitely increased when Angiotensin II was used, even if the catheter tip was keeping in the internal iliac arteries. The optimal catheter position of transcatheter arterial chemotherapy for gynecologic malignancies is at proximal uterine artery. Since Angiotensin II-induced hypertension may increase blood flow of tumors, it seems to have indication for post-operative cases, highly advanced cases and cases with difficulties to perform superselective catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗