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Biomedical subjects

S Ohtsuka

Publications and source records attributed to S Ohtsuka.

At least 109 records · Page 6Linked to original sources
PubMed1992

[Optimal branching of hepatic artery in patients with liver cirrhosis].

Optimality in branching structure of the hepatic arterial vessel in 16 patients with liver cirrhosis was studied. The controls used in this study were 14 patients with gastric or colonic cancer not accompanied by liver dysfunction. Optimality principle was based on the concept that blood vessel size and arrangement provided for blood flow with minimum energy loss. Measurements were made of parent and branch vessel diameters from selective celiac arteriogram. After that we measured the included angles of the branch-points of portal vein using ultrasonography. The branch-points of interest were the third bifurcations of right intrahepatic portal vein and artery. The following results are presented in terms of three parameters (r2(2)/r1(2), r1/r0, and r2/r0). The theoretical equations have been shown by several authors. The curve representing these equations was shown by Zamir. We analyzed the scatter of the data points and compare the theoretical and actual results with them. The extent of the scatter is studied making a comparison between control patients and patients with cirrhosis. The data points in control patients were plotted near the theoretical curve. In patients with cirrhosis, the data points show a definite tendency to be plotted far away from the theoretical curve, when we take account of both vessel diameters and branching angles. This discrepancy between theoretical values and actual data in patients with cirrhosis is considered to be caused by the following factors which may influence the vascular structure; hemodynamic change caused by increase of intrahepatic shunt, and morphological change caused by increased fibrosis or/and parenchymal nodules of the liver.

Celiac Artery↗
PubMed1991

Isolation and characterization of 1,200 kDa peptide of alpha-connectin.

When rabbit skeletal muscle myofibrils were kept for 12 h at 4 degrees C, alpha-connectin was partially degraded and 1,200 kDa peptide was newly formed [Takahashi, K. & Takai, H. (1988) Abst. 80th Jpn. Soc. Zootech. Sci. p-102]. The latter was isolated together with remaining alpha-connectin. Ultracentrifugation of the mixture at low ionic strength resulted in sedimentation of alpha-connectin, leaving the 1,200 kDa peptide in the supernatant. Physicochemical properties of the isolated 1,200 kDa peptide were investigated: UV absorption spectra, circular dichroism spectra, amino acid composition, and molecular size and shape. Polyclonal antibodies against the 1,200 kDa peptide [PcAb(1200)] bound the Z line and I-band. The position of the stripe in the I band near the N1 line due to the binding of PcAb(1200) moved both away from the Z lines and from the A band as sarcomeres were elongated. Therefore, it is considered that the 1,200 kDa portion of alpha-connectin is elastic.

Actins↗
PubMed1990

Cutaneous pharmacodynamics of transdermally delivered isosorbide dinitrate.

Laser doppler velocimetry (LDV) has been used to assess the cutaneous pharmacodynamics of isosorbide dinitrate (ISDN) following transdermal delivery of the drug from prototypal patches. The delivery systems, which were saturated with ISDN, (a) produced various degrees of skin occlusion and (b) spanned a six-fold range of adhesiveness. The patches were applied to the ventral forearm skin of 10 healthy volunteers and the local ISDN-induced increase in local skin blood flow was determined using LDV by locating the probe in a central hole in the delivery system. Measurements were made for 1.5 hr and the pharmacodynamics were quantified by (i) the maximum LDV response and (ii) the area under the LDV response versus time curve. These parameters were not sensitive to patch occlusivity. They were significantly (P less than 0.01) dependent on patch adhesiveness, though, and decreased with increasing adhesion. Although this observation suggested that ISDN diffusion through the adhesive could determine, at least in part, the rate of drug delivery, it was subsequently demonstrated that ISDN release (in vitro, into a perfect "sink") was unaffected by the level of cross-linking in the adhesive polymer. Because the drug was present in all systems at unit thermodynamic activity, these results cannot be explained on the basis of altered ISDN partitioning at the device-stratum corneum interface. We speculate that the in vivo-in vitro discrepancy may be due to the efficiency of skin contact achieved by different adhesives: that is, the more adhesive, less flexible systems make poorer contact with the skin surface, thereby decreasing the effective surface area of drug delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗
PubMed1990

Effects of acutely impaired regional function on remote myocardial wall motion and blood flow in the canine left ventricle studied by coronary occlusion and hypoxic perfusion.

STUDY OBJECTIVE: The aim was to examine whether regional myocardial dysfunction has a significant effect on the wall motion and blood flow in remote non-ischaemic regions. DESIGN: Two different severities of regional dysfunction were produced by occluding the left anterior descending coronary artery and perfusing it with a hypoxic solution. Haemodynamic variables were otherwise identical in the two conditions. The relationship of regional dysfunction in the left anterior descending artery region to regional wall motion and regional myocardial blood flow in the left circumflex artery region were examined. EXPERIMENTAL MATERIAL: 22 anaesthetised mongrel dogs, 9-16 kg, were used for the studies: 14 for the regional wall motion studies, and eight for the regional myocardial blood flow studies. MEASUREMENTS AND MAIN RESULTS: Segment shortening in the left anterior descending artery region was impaired differently in the two conditions: arterial occlusion caused a bulge, while hypoxic perfusion caused only mild hypokinesis. Segment shortening and the myocardial blood flow in the left circumflex artery region were augmented similarly in the two conditions. Left ventricular end diastolic pressure and end diastolic segment length in the left circumflex region were increased and aortic pressure was slightly decreased by left anterior descending artery occlusion and hypoxic perfusion, but there was no significant difference between the two conditions. Heart rate was not affected. CONCLUSION: The augmentation of wall motion and blood flow of the remote myocardium does not depend on the magnitude of acutely induced regional dysfunction per se. The augmented wall motion in the remote region is unlikely to be due to mechanical unloading of the remote myocardium due to an intraventricular regional interaction, but rather to the Frank-Starling mechanism and left ventricular afterload reduction following acute ischaemia.

Animals↗
PubMed1990

New trend of cardiac imaging--intravenous coronary arteriography by synchrotron radiation.

Synchrotron radiation is a broadspectrum intense X-ray beam. Selected X-ray wavelength was obtained by Bragg reflex. That is a monochromatic beam, which has a high spatial resolution, and has a K-edge discontinuity in attenuation coefficient, which, by energy subtraction, contributes to improve time resolution. An attempt to apply this method to intravenous coronary arteriography was performed in 7 anesthetized dogs. The beam was obtained by synchrotron radiation from accumulation ring, was reflected by silicon crystal, and was detected by 7 inch image intensifier system. Two-dimensional real time images were recorded on video tape. Phantom experiment was also performed. In dogs, coronary arteries were clearly distinguished by synchrotron radiation, especially at real time by video system. Phantom experiment suggested that coronary arteries could be visualized even over the visualized left ventricle. In conclusion, synchrotron radiation using two-dimensional real time images is expected to be useful in intravenous coronary arteriography in man.

Animals↗
PubMed1990

[Digital plethysmogram in women with climacteric disturbance after cold-water challenge test and effect of estrogen].

Immediately after a cold-water challenge test (C-W test) the pulse height to the digital plethysmogram descended (descent wave: D wave), and a congestion wave (C wave) occurred after the D wave. Then the recovery wave (R wave) continued after the C wave. The effects of estrogen on the digital plethysmogram under the C-W test are as follows. (1) The D wave was less than 25% in young women and women without climacteric disturbance. (2) The recovery rate of the C wave in young women was better than in climacteric women without climacteric disturbance. (3) The before value for A1B'1/B'1C1 in the C-W test of young women was 1.0, and the other values during the C-W test did not change significantly compared with the before values. (4) U-time rose only temporarily in the former case. In addition the recovery rate of the R wave after the administration of premarin in women with climacteric disturbance was 19.3%, and this was a significant improvement over the cases without administration. The recovery rate of the R wave in the same women after the administration of premarin and cercine increased to 48.3% (p less than 0.01). These data suggested that estrogen may be able to control the function of the autonomic nervous system in climacteric woman.

Adolescent↗
PubMed1990

[Immunogenetic factors influencing HBV carrier state, the seroconversion and the development of chronic liver disease].

In order to investigate the immunogenetic factors associated with hepatitis B virus (HBV) carrier state, the HBe seroconversion and the development of chronic liver disease, HLA typing were performed in 278 asymptomatic HBV carriers (ASC) and 110 patients with chronic B type hepatitis (CH). HLA typing was also performed in 178 vaccinees who had received hepatitis B vaccine. The significantly decreased frequencies of DR1 and DRw13 were found in ASC, CH and non-responders to HB vaccine. This suggests that DR1 and DRw13 may be associated with the elimination of HBV. The frequency of DR4.2 was increased in ASC, but decreased in CH. The seroconversion rate of DR4.2 positive CH as well as ASC was high. Therefore DR4.2 may have relevance to the seroconversion from HBeAg to anti-HBe.

Carrier State↗
PubMed1989

[A study on fatty liver in health examination participants].

We investigated the condition of the liver in a total of 5486 subjects (3889 males and 1597 females) who received adult-disease screening examinations. The following results were obtained. 1. Fatty liver was found in 13.9% of the males and 3.8% of the females with a male/female ratio of about 3.7 to 1. In males, the prevalence of fatty liver was lower in those in their 20's than in any other age ranks, while there was little difference in the age range from the 30's to the 50's. In females, the prevalence sharply increased in those in their 50's. 2. The percentage of fatty liver increased with the obesity index in both males and females. 3. With respect to alcohol drinking, the prevalence of fatty liver was not affected by the presence or absence of alcohol drinking, the daily drinking quantity and total drinking quantity. 4. Of those screened for adult disease, 14.7% of the males and 2.7% of the females had abnormal liver function, with a male/female ratio of about 5.4 to 1. In both males and females, the prevalence of fatty liver was higher in those who had abnormal rather than normal liver function.

Adult↗
PubMed1989

Studies on GnRH agonist suppression of estrogen production in patients with endometriosis.

The chronic administration of GnRH agonists to women results in the reversible suppression of estrogen production by the ovary. In the present study, the mechanism of the GnRH agonist suppression of estrogen production was investigated in patients with endometriosis. During the treatment with intranasal buserelin spray, the concentration of serum estradiol-17 beta (E2) was suppressed to near-castrate levels. Despite this marked suppression of serum E2, immunoreactive LH and FSH levels in serum were not changed. On the other hand, serum bioactive LH was markedly reduced. It was also observed during the treatment that the pituitary LH pulse disappeared and pituitary response to exogenous GnRH was significantly suppressed. In contrast, ovarian response to human menopausal gonadotropin (hMG) was not altered during the treatment. These findings suggest that the GnRH agonist suppression of estrogen production in the patients with endometriosis is through both suppression of the secretion of biologically active LH and the reduction of the LH pulse, but not through a direct inhibitory effect on ovarian estrogen biosynthesis.

Administration, Intranasal↗
PubMed1989

Estrogen stimulates gonadotropin-releasing hormone release from rat hypothalamus independently through catecholamine and histamine in vitro.

Estradiol is known to stimulate gonadotropin-releasing hormone release from the rat medio-basal hypothalamus. Studies were made in an in vitro perifusion system on whether catecholamine and/or histamine was involved in estradiol-induced GnRH release. Normal cycling female rats were decapitated in diestrus II and their medio-basal hypothalami were combined and, perifused with Earl's balanced salt solution containing 0.01% bovine serum albumin bubbled with 95% O2 and 5% CO2. The levels of norepinephrine, dopamine, and histamine and of GnRH in the effluent were measured by HPLC and radioimmunoassay, respectively. Administration of 10(-6) mol/l estradiol resulted in releases of norepinephrine, dopamine, histamine and GnRH at levels of 98, 70, 91 and 288%, respectively, of initial values. Administration of 10(-6) mol/l norepinephrine or dopamine resulted in no increase in histamine release, and administration of 10(-6) mol/l histamine did not increase release of norepinephrine or dopamine. These data suggest that estradiol stimulates the releases of GnRH, catecholamine and histamine from the rat medio-basal hypothalamus, and that it increases GnRH release independently through catecholamine and histamine. As we found previously that norepinephrine or histamine stimulates GnRH release from the medio-basal hypothalamus, we conclude that estradiol stimulates releases of norepinephrine and histamine, resulting in GnRH release from the medio-basal hypothalamus.

Animals↗
PubMed1988

Vasoactive intestinal peptide stimulates gonadotropin-releasing hormone release from rat hypothalamus in vitro.

The effects of vasoactive intestinal peptide (VIP) on the releases of LH and GnRH were examined in a sequential double chamber perifusion system by perfusing the medio-basal hypothalamus and/or pituitary excised from normal female rats in diestrus or ovariectomized rats. When the medio-basal hypothalamus and pituitary from normal rats in series were perifused with VIP (10(-6) mol/l), the concentration of LH in the efflux was increased by 59-181% above that before the injection (P less than 0.05), VIP having a dose-dependent effect. VIP had no effect on LH release from the pituitary perifused alone. Infusion of VIP at 10(-6) mol/l induced a significant release (84-159% increase, P less than 0.05) of GnRH from the medio-basal hypothalamus. Infusion of 10(-6) mol/l VIP induced a significant release (41-99% increase, P less than 0.05) of LH in ovariectomized rats. These findings suggest that VIP induces GnRH release from the medio-basal hypothalamus, resulting in LH release from the pituitary, and that this process does not require ovarian estrogen.

Animals↗