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Biomedical subjects

K Shiraishi

Publications and source records attributed to K Shiraishi.

At least 19 recordsLinked to original sources
PubMed1995

Developmental changes in the distribution of the endoplasmic reticulum and inositol 1,4,5-trisphosphate receptors and the spatial pattern of Ca2+ release during maturation of hamster oocytes.

During maturation of hamster oocytes, the distribution of the endoplasmic reticulum (ER) and inositol 1,4,5-trisphosphate receptors (InsP3Rs) was found to change dramatically, as observed using confocal microscopy with DiI and electron microscopy for the ER and immunohistochemistry for InsP3Rs. In immature oocytes at the germinal vesicle (GV) stage, ER and InsP3Rs were located predominantly in several large masses near the surface and also in the perinuclear region near the surface. In contrast, fine ER networks and low-density InsP3Rs were present in the inner cytoplasm. The ER appeared to be formed as vesicles from annulate lamellae (AL) in the subcortical area. Rises in Ca2+ concentration occurred in the cytoplasm and the GV when immature oocytes were inseminated, but clear Ca2+ waves did not occur. Ca2+ rises began preferentially from the perinuclear region in response to low doses of serotonin or to uniform stimulation of InsP3Rs with photocleavage of caged InsP3. Serum also induced inhomogeneous Ca2+ release, shown by nonpropagating Ca2+ rises at multiple surface sites. Between the GV stage and prometaphase I the number and size of the surface ER masses increased, and the AL disappeared. This quantitative ER maturation was followed by a second step, spatial maturation. After prometaphase I, surface ER masses gradually dispersed to a number of much smaller ER clusters near the surface and, together with the perinuclear mass, were incorporated into thicker ER networks, resulting in a reticular pattern of the ER with small patches of InsP3Rs throughout the mature egg. The ER shifted to the peripheral surface with apposition to cortical granules. These developmental changes in ER Ca2+ stores may account, at least partly, for the acquisition of the ability of an egg to undergo normal fertilization.

Animals↗
PubMed1995

Topography of binaural interaction in the auditory brainstem response.

The scalp topography of binaural interaction (BI) in the auditory brainstem response (ABR) was studied in fourteen normal individuals. BI was observed from all recording sites of the scalp, and the peak amplitude was noted mostly in the bilateral parietal and occipital regions. There was a significant difference in amplitude shown by significance probability mapping (SPM) when the waveform obtained by binaural stimulation was compared with the sum of the waves obtained by monaural stimulation. The topography of BI was different from that of the wave III and the wave IV/V complex. In contrast to previous reports by other workers, we found that BI mainly corresponded to the first half of the wave IV/V complex.

Adult↗
PubMed1995

Analysis of auditory brainstem response waveforms derived ipsilaterally and contralaterally to monaural stimulation.

The auditory brainstem responses (ABRs) obtained from 28 normal healthy adults were studied using the ipsilateral and contralateral recordings from the positions of vertex and each mastoid to monaural stimulation. Each wave of ABRs recorded by ipsilateral and contralateral derivations to stimulation site showed slightly significantly differences. Comparing the ipsilateral and contralateral data, the latencies of waves II and V showed a slightly small reduction in the ipsilateral recording, while these of waves III and IV showed a small increase. Next, the distributions of potentials and latencies of waves II to V were investigated from ABRs situating different electrodes in mid-coronal array of the scalp and non-cephalic reference electrode on the seventh cervical vertebra (CVII). The results of latencies showed the reverse relation to the data obtained from the ipsilateral and contralateral recordings using the reference electrodes on each mastoid. These facts suggest that the comparable differences of latencies in the bilaterally recorded ABRs are explained by the pseudo-phenomena of differential recordings, which the phase delayed or advanced potential propagated to each mastoid being reference electrode position.

Acoustic Stimulation↗
PubMed1995

A device for controlling odorant stimulation and olfactory evoked responses in humans.

We developed a device for odorous stimuli control to record olfactory evoked responses from the human scalp. The characteristics of the apparatus are as follows. Translating the subject's respiration into electric signals with a sensor attached to the nose. The period and timing of odorous stimuli could be adjusted, so that stimuli could be synchronous with respiration. The interstimulus interval could be arbitrarily selected once every 1 to 9 respiration(s) so that adaptation could be prevented. We obtained evoked responses to odorous stimuli using this apparatus from the human scalp, whose positive peak latencies were approximately 350 and 700 msec. Such responses were not recorded if oxygen stimuli were used instead of odorous stimuli or with click sounds produced by the switching electromagnetic valve. Three types of odorant evoked scalp potentials were obtained in normal human subjects. The first type consisted mainly of two positive peaks with a peak latency of about 350 msec (P350) and about 700 msec (P700). The second type and the third type consisted of only one positive peak with a peak latency of about 350 msec and 700 msec, respectively. Such a P350 or P700 peak as that observed in the normal subjects was not detected in anosmic patients.

Electric Stimulation↗
PubMed1995

Expression of granulocyte colony-stimulating factor receptor on CD10-positive human B-cell precursors.

We examined the expression of CD10 and G-CSF receptor (G-CSFR) on the lymphoid population of mononuclear cells obtained from bone marrow (BM) using two-colour analysis. In the BM of children with ALL in remission, the CD10+ population was significantly increased (20.6 +/- 5.1% compared with that of controls (2.5 +/- 0.5%). More than half (61.3 +/- 2.9%) of the CD10+ cells co-expressed G-CSFR, but not CD13. These results indicate G-CSFR+ B-cell precursors are markedly increased in BM of ALL in remission, suggesting the probable involvement of G-CSF in the human early B-cell ontogeny.

Adolescent↗
PubMed1995

[mRNA expression and protein localization of placental tissue protein 11, 12, 19 in gynecologic malignant tumors].

In recent years, the localization and function of placental tissue proteins (PPs), extracted by Bohn et al., have been extensively studied, the genetic code has been identified for each of the PPs. The present study was carried out to clarify the mRNA expression and protein localization of PP11, PP12, PP19 at the cell level and also to define PP19 the nature of which has remained obscure. PP19 was said to be placenta-derived S-100P. PP11 mRNA was not expressed in cytotrophoblast-derived normal placental tissue or endometrium-derived normal cells, but was expressed in syncytiotrophoblast-derived normal placental tissue, and in choriocarcinoma and endometrial adenocarcinoma, suggesting its involvement in carcinogenesis. PP12 mRNA was expressed in cytotrophoblast-derived normal placental tissue or endometrium-derived normal cells, but was not expressed in syncytiotrophoblast-derived normal placental tissue, choriocarcinoma or endometrial adenocarcinoma, suggesting that this protein serves in the function of normal cells. PP19 mRNA was expressed in the squamous epithelial cells of the uterine cervix and the villous cells, PP19 was localized in more differentiated regions, where cells tended toward keratinization, in both normal and dysplastic uterine cervices. In squamous cell carcinoma, PP19 was localized in more differentiated cells with a large cytoplasm. PP19 mRNA was not expressed in normal endometrial glands, but was detected in endometrial adenocarcinoma, suggesting its involvement in cell differentiation in cervical epitherial cells.

Base Sequence↗
PubMed1994

Daily intakes of alkaline earth metals in Japanese males.

Diet samples were collected for two duplicate portion studies and one market basket study. 226Ra in the diet samples was determined by alpha spectrometry and daily intake was estimated as 23 mBq (0.62 pCi) per person. Other alkaline earth metals were determined by inductively coupled plasma atomic-emission spectrometry. Average mineral intakes of calcium, magnesium, strontium, and barium were 0.55 g, 0.21 g, 2.3 mg, and 0.39 mg, respectively. Element ratios magnesium:calcium 0.38, strontium:calcium 4.2 x 10(-3), barium:calcium 7.1 x 10(-4), and 226Ra:calcium 1.1 x 10(-12) were found in the diet; these compared with element ratios in Japanese vertebrae of magnesium:calcium 0.1:1, strontium:calcium 3.1 x 10(-4), barium:calcium 2.7 x 10(-5), and radium:calcium 2.6 x 10(-14). Observed ratios, defined as the element ratio in bone divided by the respective element intake ratio in Japanese males, were as follows: 226Ra 0.02, magnesium 0.03, strontium 0.07, and barium 0.04.

Adult↗
PubMed1994

Application of an air-filled tube for measuring intraesophageal pressure.

We devised a new method for measuring esophageal pressure (Pes) with use of a flexible tube without a balloon at a constant rate of airflow through the tube into the esophagus (balloonless method). A study with 133Xe showed that the air that accumulated in the esophagus did not interfere with the measurement of Pes. We measured dynamic compliance (Cdyn) and pulmonary resistance (RL) with the balloonless method in 19 subjects and obtained a static deflation pressure-volume curve (P-V curve) in 10 other subjects. Cdyn was 0.243 +/- 0.099 l/cmH2O and RL was 1.52 +/- 0.42 cmH2O.l-1.s. In 6 of the 10 subjects, a P-V curve was also obtained with the balloon tube (balloon method). K, the index of compliance in the exponential function V = V0(1-e-KP) where V0 is volume at infinite pressure, was 0.136 +/- 0.040 cmH2O-1 with the balloonless method and 0.153 +/- 0.023 cmH2O-1 with the balloon method. No statistically significant difference was found between these two values. In conclusion, Cdyn, RL, and the P-V curve can be obtained precisely with the balloonless method.

Adult↗
PubMed1993

Subtype of muscarinic receptors mediating relaxation and contraction in the rat iris dilator smooth muscle.

1. Carbachol produced a relaxation of dilator muscle at a concentration lower than 1 microM and a contraction at a concentration higher than 1 microM. 2. We studied the effects of the M1-selective antagonist, pirenzepine, the M2-selective antagonist, himbacine, the M3-selective antagonist, 4-diphenyl-acetoxy-N-methylpiperidine methiodide (4-DAMP) and the non-selective antagonist, atropine, on carbachol-induced relaxation and contraction of the rat iris dilator smooth muscle. All the antagonists competitively inhibited both the responses to carbachol. 3. In relaxation and contraction, the low affinity of pirenzepine and himbacine suggest that the rat iris dilator smooth muscle receptors are not of the M1 and M2 subtypes. In contrast, 4-DAMP potently inhibited the carbachol-induced relaxation and contraction with affinities similar to those reported for the M3 subtype. 4. Carbachol-induced relaxation and contraction of the rat iris dilator appears to be mediated through a homogeneous population of M3 subtype.

Alkaloids↗
PubMed1993

Zinc enhances kainate neurotoxicity in the rat brain.

Zinc, a trace element, is epileptogenic in rats and rabbits. Its distribution in the CNS is mainly localized in the hippocampus, where kainate (KA) can develop neuronal damage with limbic seizures. We examined the zinc neurotoxicity int he rat brain with KA. The unilateral intracarotid artery infusion of zinc chloride seemed to enhance the specific binding of KA at the ipsilateral hippocampus in the method of receptor-binding autoradiography. Actually, the zinc infusion followed by the intravenous injection of KA 0.5 mg-1 kg-1 body weight induced ipsilateral neuronal damage at the cortex and the CA3-4 of the hippocampus. A potent non-N-methyl-D-aspartate (NMDA) antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) could not change KA binding, but could partially prevent that neuronal damage. According to these results, we consider that zinc administration through intracarotid infusion can enhance the KA neurotoxicity in its binding activities and that CNQX is potent to decrease KA neurotoxicity in the KA insulted area in the rat brain.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1993

Impaired erythrocyte deformability and membrane fluidity in alcoholic liver disease: participation in disturbed hepatic microcirculation.

The erythrocyte deformability, membrane fluidity, mean corpuscular volume (MCV), and lipid compositions of erythrocyte membrane were investigated to evaluate the possible role in disturbed hepatic microcirculation in alcoholic liver disease. Erythrocyte deformability was assessed in 37 alcoholic patients and 20 normal subjects. Erythrocyte deformability determined by the filtration method was found to be decreased significantly in alcoholic patients. Erythrocyte membrane fluidity in alcoholic liver disease analysed by fluorescence recovery time after photobleaching was decreased significantly. The decrease of erythrocyte membrane fluidity in alcoholic patients correlated significantly with a decrease of erythrocyte deformability (r = -0.65, P < 0.02). The increased MCV in alcoholic liver disease also correlated with a decrease of erythrocyte deformability significantly (r = 0.652, P < 0.02). The lipid compositions of erythrocyte membrane were abnormal in alcoholic liver disease; the phosphatidylcholine:sphingomyelin ratio was increased (P < 0.001) and unsaturated:saturated fatty acid ratio was decreased (P < 0.01). We conclude that, in alcoholic liver disease, the decreased erythrocyte deformability was closely associated with changes of membrane fluidity and MCV. It was also associated with abnormalities of membrane lipid compositions. It is speculated that these abnormalities of erythrocytes result in further reduction of sinusoidal blood flow in alcoholic liver disease, and consequently disturb metabolic functions of the liver.

Analysis of Variance↗
PubMed1993

Sonography of urethral calculi.

We performed sonography in 7 males with membranous and posterior urethral calculi. Sonography demonstrated the urethral calculi in all 7 patients. These findings suggest that sonography is useful as a noninvasive screening technique for urethral calculi.

Adult↗
PubMed1993

Inhibitory effect of pilocarpine on norepinephrine release from electrically stimulated iris dilator muscles of rabbits as a most possible mechanism of pilocarpine-induced miosis.

Instillation of pilocarpine-induced a miosis in a rabbit. In an isolated iris sphincter muscle of rabbit, pilocarpine induced a small contraction and behaved as an antagonist of carbachol. The contractile response of an isolated rabbit dilator muscle to a field stimulation was inhibited by pilocarpine. This inhibitory action of pilocarpine was antagonized by atropine in a concentration-dependent manner. An amount of norepinephrine released from the electrically stimulated dilator muscle was inhibited by pilocarpine. The inhibitory effect of pilocarpine on norepinephrine release was decreased by atropine. A following explanation is proposed as a most possible mechanism for the pilocarpine-induced miosis in the rabbit. Pilocarpine activates the prejunctional cholinoceptors to inhibit norepinephrine release from the adrenergic nerve in the dilator muscle. Thus pilocarpine decreases tonus of the dilator muscle and induces the miosis.

Animals↗
PubMed1993

[Usefulness of polymerase chain reaction (PCR) technique in making early diagnosis and treatment of cytomegalovirus and Pneumocystis carinii-pneumonia in patients with hematological neoplasms].

Recently, the incidence of opportunistic infections in patients with hematological neoplasms has been markedly increasing. However, early and definitive diagnosis and treatment of these infections remain difficult. In this study, we report three patients, a 47-year-old female with ATL, a 54-year-old female with CML and a 65-year-old female with ATL. All these cases were complicated with pneumonia caused by Pneumocystis carinii (Pc) or cytomegalovirus (CMV). They were successfully treated with sulfamethoxazole/trimethoprim or ganciclovir after detection of the respective microorganisms from sputum samples in the early stage of the infections by polymerase chain reaction (PCR) method. The above clinical evidence demonstrated the PCR technique to be a rapid and sensitive diagnostic procedure for the detection of Pc or CMV and to be helpful for the early initiation of appropriate treatment of the infections in patients with hematological neoplasms.

Aged↗
PubMed1992

Effect of chronic hypoxia on fibronectin in plasma, bronchoalveolar lavage fluid and liver of rats.

The present study was undertaken to measure fibronectin (FN) concentration in plasma and bronchoalveolar lavage fluid (BALF) with an enzyme linked immunosorbent assay (ELISA) method, to observe the distribution of FN in liver with an immunohistochemical stain method and to investigate the effect of chronic normobaric hypoxia on them in experimental rats. The results showed that chronic hypoxia caused a significant decrease in plasma FN concentration while BALF FN concentration and the distribution of FN in the liver were not significantly affected, suggesting that the change in FN in the lower respiratory tract can not be reflected by the change in plasma FN concentration and that the decrease in plasma FN concentration can not be attributed to the change in liver FN secretion. The decrease in plasma FN concentration may lead to a decrease in the defence ability of the body and may contribute to the development of hypercoagulability observed in some patients with chronic hypoxia.

Animals↗