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Biomedical subjects

Y Shiraishi

Publications and source records attributed to Y Shiraishi.

At least 19 recordsLinked to original sources
PubMed1999

Cupidin, an isoform of Homer/Vesl, interacts with the actin cytoskeleton and activated rho family small GTPases and is expressed in developing mouse cerebellar granule cells.

A developmentally regulated Homer/Vesl isoform, Cupidin (Homer 2a/Vesl-2Delta11), was isolated from postnatal mouse cerebellum using a fluorescent differential display strategy. The strongest expression of Cupidin was detected in the cerebellar granule cells at approximately postnatal day 7. Cupidin was enriched in the postsynaptic density fraction, and its immunoreactivity was concentrated at glomeruli of the inner granular layer when active synaptogenesis occurred. Cupidin protein could be divided into two functional domains: the N-terminal portion, which was highly conserved among Homer/Vesl family proteins, and the C-terminal portion, which consisted of a putative coiled-coil structure, including several leucine zipper motifs. The N-terminal fragment of Cupidin, which was able to associate with metabotropic glutamate receptor 1 (mGluR1), also interacted with F-actin in vitro. In keeping with this, F-actin immunocytochemically colocalized with Cupidin in cultured cerebellar granule cells, and a Cupidin-mGluR1-actin complex was immunoprecipitated from crude cerebellar lysates using an anti-Cupidin antibody. On the other hand, the C-terminal portion of Cupidin bound to Cdc42, a member of Rho family small GTPases, in a GTP-dependent manner in vitro, and Cupidin functionally interacted with activated-Cdc42 in a heterologous expression system. Together, our findings indicate that Cupidin may serve as a postsynaptic scaffold protein that links mGluR signaling with actin cytoskeleton and Rho family proteins, perhaps during the dynamic phase of morphological changes that occur during synapse formation in cerebellar granule cells.

Actins↗
PubMed1998

Cortical anesthesia reduced the amplitude of local P300 event-related potential in rabbits by auditory oddball paradigm.

Eight rabbits were employed in this study. Under anesthesia, one electrode was fixed in the skull at the bregma and another was fixed, with three guide cannulas around it, at a parietal point 5 mm lateral to the bregma. Two weeks later, with a 10-day interval, either 0.5% lidocaine (9 microl) or the same volume of normal saline was injected into cortex through the cannulas. Event-related potentials (ERPs) evoked by auditory oddball paradigm were recorded before and after the injections in alert rabbits. The probability of occurrence for the 2 and 1 kHz stimulus tones was 90% (frequent) and 10% (rare), respectively. After lidocaine injection, P3 amplitude to rare stimuli decreased to 37.6% (P < 0.05), while N1 did not show any significant changes. ERPs from the bregma were intact. P3 and N1 did not change after normal saline injection. Our results show that local parietal cortex is one of the P3 generators.

Anesthetics, Local↗
PubMed1998

Early pulmonary resection for localized Mycobacterium avium complex disease.

BACKGROUND: Results of antituberculous chemotherapy for Mycobacterium avium complex disease remain disappointing. Pulmonary resection during an early stage of the disease, therefore, may be beneficial to patients whose disease is localized and who can tolerate a resectional operation. METHODS: Thirty-three patients with localized M avium complex disease underwent 33 pulmonary resections between 1979 and 1996. There were 17 males and 16 females, with a mean age of 50 years (range, 30 to 69 years). Lobectomy was performed in 26 patients, pleuropneumonectomy in 1, segmentectomy in 5, and wedge resection in 1. RESULTS: There was no operative mortality. After pulmonary resection, 31 (94%) patients attained sputum-negative status. Bronchopleural fistula occurred in one patient who underwent a right upper lobectomy. There were two late deaths. A patient with bronchopleural fistula died of respiratory failure two years postoperatively. Another patient died of an unknown cause 12 years postoperatively. Of the 31 patients with negative sputum status postoperatively, only 2 patients (6%) had relapse at 1 and 9 years after operation. CONCLUSIONS: We recommend that patients with this disease be considered for pulmonary resection as early as possible.

Adult↗
PubMed1998

Effect of cilostazol, a phosphodiesterase type III inhibitor, on histamine-induced increase in [Ca2+]i and force in middle cerebral artery of the rabbit.

1. The effect of cilostazol, an inhibitor of phosphodiesterase type III (PDE III), on the contraction induced by histamine was studied by making simultaneous measurements of isometric force and the intracellular concentration of Ca2+ ([Ca2+]i) in endothelium-denuded muscle strips from the peripheral part of the middle cerebral artery of the rabbit. 2. High K+ (80 mM) produced a phasic, followed by a tonic increase in both [Ca2+]i and force. Cilostazol (10 microM) did not modify the resting [Ca2+]i, but it did significantly decrease the tonic contraction induced by high K+ without a corresponding change in the [Ca2+]i response. 3. Histamine (3 microM) produced a phasic, followed by a tonic increase in both [Ca2+]i and force. Cilostazol (3 and 10 microM) significantly reduced both the phasic and tonic increases in [Ca2+]i and force induced by histamine, in a concentration-dependent manner. 4. Rp-adenosine-3':5'-cyclic monophosphorothioate (Rp-cAMPS, 0.1 mM), a PDE-resistant inhibitor of protein kinase A (and as such a cyclic AMP antagonist), did not modify the increases in [Ca2+]i and force induced by histamine alone, but it did significantly decrease the cilostazol-induced inhibition of the histamine-induced responses. 5. In Ca2+-free solution containing 2 mM EGTA, both histamine (3 microM) and caffeine (10 mM) transiently increased [Ca2+]i and force. Cilostazol (1-10 microM) (i) significantly reduced the increases in [Ca2+]i and force induced by histamine, and (ii) significantly reduced the increase in force but not the increase in [Ca2+]i induced by caffeine. 6. In ryanodine-treated strips, which had functionally lost the histamine-sensitive Ca2+ storage sites, histamine (3 microM) slowly increased [Ca2+]i and force. Cilostazol (3 and 10 microM) lowered the resting [Ca2+]i, but did not modify the histamine-induced increase in [Ca2+]i, suggesting that functional Ca2+ storage sites are required for the cilostazol-induced inhibition of histamine-induced Ca2+ mobilization. 7. The [Ca2+]i-force relationship was obtained in ryanodine-treated strips by applying ascending concentrations of Ca2+ (0.16-2.6 mM) in Ca2+-free solution containing 100 mM K+. Histamine (3 microM) shifted the [Ca2+]i-force relationship to the left and increased the maximum Ca2+-induced force. Under the same conditions, whether in the presence or absence of 3 microM histamine, cilostazol (3-10 microM) shifted the [Ca2+]i-force relationship to the right without producing a change in the maximum Ca2+-induced force. 8. It is concluded that, in smooth muscle of the peripheral part of the rabbit middle cerebral artery, cilostazol attenuates the histamine-induced contraction both by inhibiting histamine-induced Ca2+ mobilization and by reducing the myofilament Ca2+ sensitivity. It is suggested that the increase in the cellular concentration of cyclic AMP that will follow the inhibition of PDE III may play an important role in the cilostazol-induced inhibition of the histamine-contraction.

Animals↗
PubMed1998

Effect of propofol on norepinephrine-induced increases in [Ca2+]i and force in smooth muscle of the rabbit mesenteric resistance artery.

BACKGROUND: Propofol (2,6-diisopropylphenol) possesses vasodilating activity in vivo and in vitro. The propofol-induced relaxation of agonist-induced contractions in small resistance arteries has not been clarified. METHODS: The effect of propofol was examined on the contractions induced by norepinephrine and high K+ in endothelium-denuded rabbit mesenteric resistance artery in vitro. The effects of propofol on the [Ca2+]i mobilization induced by norepinephrine and high K+ were studied by simultaneous measurement of [Ca2+]i using Fura 2 and isometric force in ryanodine-treated strips. RESULTS: Propofol attenuated the contractions induced by high K+ and norepinephrine, the effect being greater on the high K+-induced contraction than on the norepinephrine-induced contraction. In Ca2+-free solution, norepinephrine produced a transient contraction resulting from the release of Ca2+ from storage sites that propofol attenuated. In ryanodine-treated strips, propofol increased the resting [Ca2+]i but attenuated the increases in [Ca2+]i and force induced by both high K+ and norepinephrine. In the presence of nicardipine, propofol had no inhibitory action on the residual norepinephrine-induced [Ca2+]i increase, whereas it still modestly increased resting [Ca2+]i, as in the absence of nicardipine. CONCLUSIONS: In smooth muscle of the rabbit mesenteric resistance artery, propofol attenuates norepinephrine-induced contractions due to an inhibition both of Ca2+ release and of Ca2+ influx through L-type Ca2+ channels. Propofol also increased resting [Ca2+]i, possibly as a result of an inhibition of [Ca2+]i removal mechanisms. These results may explain in part the variety of actions seen with propofol in various types of vascular smooth muscle.

Anesthetics, Intravenous↗
PubMed1998

[Anesthetic management of a patient with antiphospholipid syndrome].

A 46-year-old woman with antiphospholipid syndrome (APS) underwent an emergent laparotomy. The symptoms and signs of APS are reported to be thrombosis, habitual abortion, thrombocytopenia and biological false positive (BFP) for syphilis' tests. Clinical symptoms are based on hypercoagulation of blood, while prothrombin time (PT) activity and activated partial thromboplastin time (APTT) are prolonged. Although we have selected general endotracheal anesthesia without epidural catheterization, we recommend that the regional analgesia is suitable for those APS patients with abnormality of coagulation. If PT and APTT differ from clinical symptoms, we have to think about APS and manage the patients carefully as APS.

Anesthesia, General↗
PubMed1998

Use of leukocyte depletion to decrease injury after lung preservation and rewarming ischemia: an experimental model.

BACKGROUND: Hypothermia is critical for proper lung preservation. Ideally, the lungs should be maintained at the optimal preservation temperature during the entire ischemic interval. Lung rewarming during implantation is commonly observed. This study was undertaken to investigate the severity of rewarming ischemia on preservation injury and the possibility of minimizing this by use of leukocyte depletion during initial reperfusion. METHODS: Four experimental groups were tested as follows: neonatal piglet heart-lung blocks were either (1) placed on an isolated, blood-perfused, working heart-lung circuit without intervening ischemia (control, n = 6), (2) reperfused on the circuit with whole blood (WB, n = 6) after 13 hours of preservation, (3) reperfused with WB after 12 hours of preservation and 1 hour of rewarming (RWB, n = 5), or (4) reperfused with leukocyte-depleted blood for an initial 10 minutes followed by WB, after 12 hours of preservation and 1 hour of rewarming (n = 6). All groups were studied for 4 hours. RESULTS: The partial pressure of arterial oxygen and lung compliance were significantly lower in the RWB group than in controls (113.8+/-33.1 vs 417.3+/-6.2 mm Hg, p < 0.01; and 0.8+/-0.2 vs 2.9+/-0.4 ml/cm H2O, p < 0.05, respectively). Pulmonary vascular resistance and lung wet/dry weight ratios were significantly higher in the RWB group than in controls (15884.1+/-11354.8 vs 6108.3+/-1309.9 dyne x sec x cm[-5], p < 0.05; and 7.13+/-0.24 vs 5.82+/-0.35, p < 0.05, respectively). The WB and leukocyte-depleted groups did not differ significantly from controls for any measured parameter. CONCLUSIONS: This model confirms that rewarming ischemia during lung implantation exacerbates reperfusion injury. Leukocyte-depleted reperfusion as tested for a short period of time (10 minutes) ameliorates this injury and therefore should be considered for clinical lung transplantation.

Animals↗
PubMed1997

Purification and characterization of a GroEL homologue from the moderately eubacterial halophile Pseudomonas sp. #43.

We have purified to apparent homogeneity and characterized a molecular chaperonin GroEL homologue (hpGroEL) from a moderately halophilic eubacterium, Pseudomonas sp. #43. Although this halophilic bacterium requires 1-2 M NaCl for growth, hpGroEL did not require a high concentration of salt for its stability, ATPase activity and refold-promoting activity for denatured protein. The ATPase activity was even more halo-sensitive than that of GroEL from Escherichia coli. The hpGroEL protein promotes Mg(2+)-ATP-dependent refolding of urea-denatured alpha-glucosidase in the presence of E. coli-GroES, indicating that chaperonins 60 and 10 isolated from halophilic and nonhalophilic eubacteria, respectively, can cooperate with each other.

Adenosine Triphosphatases↗
PubMed1997

Peritoneal lymphatic stomata of the diaphragm in the mouse: process of their formation.

BACKGROUND: Lymphatic stomata are channels connecting the peritoneal cavity with the lymphatics in the diaphragm. The process of sequential formation of the stomata has not been studied. The objective of this study was to examine the morphogenesis of the lymphatic stomata in mice. METHODS: Ultrathin sections of diaphragms from ddY mice obtained on embryonic day 18 and postnatal days 0, 4, and 10 were observed with a transmission electron microscope. RESULTS: By embryonic day 18 and postnatal day 0, lymphatics were already observed in the submesothelial connective tissue on the peritoneal side of the fetal diaphragm. The lymphatic endothelial cells, but not the mesothelial cells covering the diaphragm, protruded short cytoplasmic processes into the submesothelial connective tissue, and these almost reached the basal surfaces of individual mesothelial cells. By postnatal days 4 and 10, the lymphatic endothelial cells frequently protruded cytoplasmic processes into the submesothelial connective tissue, and the endothelial cell processes broke the continuity of both the basal lamina beneath the mesothelial cells and the submesothelial connective tissue. Neighboring endothelial processes formed a pair of U-shaped folds that were connected with each other via intercellular junctions at the apexes of the U-shaped folds. The disassembly of the intercellular junctions between the U-shaped folds was observed, and the basal surface of the mesothelial cell faced the lymphatic lumen. Dehiscence of the intercellular junctions between the mesothelial cells overlaying the lymphatics was observed, and lymphatic stomata were present. On the pleural side of the diaphragm, lymphatics were already present on embryonic day 18, but it was not observed that the endothelial process spanned the submesothelial connective tissue to the basal surface of the mesothelial cell. CONCLUSIONS: These results suggest the following process of the formation of the lymphatic stomata. (1) Neighboring lymphatic endothelial cells span the submesothelial connective tissue to the basal surfaces of mesothelial cells. (2) The lymphatic stomata are formed by the disassembly of the intercellular junctions between the neighboring endothelial cells and between the mesothelial cells overlying the endothelial cells.

Age Factors↗
PubMed1997

P300-like potential disappears in rabbits with lesions in the nucleus basalis of Meynert.

The nucleus basalis of Meynert (nbM, substantia innominata) in the basal forebrain provides a single major source of cholinergic innervation for the entire cerebral cortex. We tested the effects of nbM lesions on rabbit P300-like potentials. The P300-like event-related potential (ERP) was recorded in 14 female adult white rabbits using a conventional auditory oddball paradigm. The probability of occurrence for the 2-kHz and 1-kHz stimulus tones was 90% (frequent) and 10% (rare), respectively. The nbM was destroyed bilaterally in seven rabbits referred to as the nbM (+) group. In the other seven rabbits [nbM (-) group], putamen nuclei (n=6) or amygdaloid nuclei (n=1) were destroyed bilaterally. The evoked responses were recorded before and 1 week after the destruction. In the nbM (+) group, P300 amplitude to rare stimuli significantly decreased after the lesion. In the nbM (-) group, no component of ERPs showed changes after the lesions. These results indicate that the nbM might be involved in the generation of the rabbit P300.

Acoustic Stimulation↗
PubMed1997

Retrieval by other procurement teams provides favorable lung transplantation outcome.

BACKGROUND: During the last 4 years, we have increasingly used lungs retrieved by other procurement teams. We therefore investigated whether the use of those lungs affected the outcome of lung transplantation. METHODS: We analyzed the results of 159 consecutive lung transplantations performed at our institution between July 1, 1992, and December 31, 1995. The transplants were divided into three groups: distant donor lungs retrieved by our team (DB group, n = 68); distant donor lungs retrieved by other teams (DX group, n = 46); and local donor lungs retrieved by our team (LB group, n = 44). One transplantation with a local donor lung retrieved by another team was excluded from the analysis. RESULTS: No significant differences were noted between the three groups in alveolar-arterial oxygen gradient immediately after transplantation (DB group, 359 +/- 18 mm Hg; DX group, 329 +/- 23 mm Hg; LB group, 327 +/- 20 mm Hg) and at 24 hours; days on ventilator; days in the intensive care unit; length of hospital stay; 30-day mortality; and actuarial 1-year survival (DB group, 81%; DX group, 87%; LB group, 89%). CONCLUSIONS: The use of donor lungs retrieved by other teams achieves an equivalently satisfactory outcome after lung transplantation as lungs retrieved by our team.

Adult↗
PubMed1997

Possible mechanisms underlying the midazolam-induced relaxation of the noradrenaline-contraction in rabbit mesenteric resistance artery.

1. The mechanisms underlying the midazolam-induced relaxation of the noradrenaline (NA)-contraction were studied by measuring membrane potential, isometric force and intracellular concentration of Ca2+ ([Ca2+]i) in endothelium-denuded muscle strips from the rabbit mesenteric resistance artery. The actions of midazolam were compared with those of nicardipine, an L-type Ca2+-channel blocker. 2. Midazolam (30 and 100 microM) did not modify either the resting membrane potential or the membrane depolarization induced by 10 microM NA. 3. NA (10 microM) produced a phasic, followed by a tonic increase in both [Ca2+]i and force. Midazolam (10-100 microM) did not modify the resting [Ca2+]i, but attenuated the NA-induced phasic and tonic increases in [Ca2+]i and force, in a concentration-dependent manner. In contrast, nicardipine (0.3 microM) attenuated the NA-induced tonic, but not phasic, increases in [Ca2+]i and force. 4. In Ca2+-free solution containing 2 mM EGTA, NA (10 microM) transiently increased [Ca2+]i and force. Midazolam (10-100 microM), but not nicardipine (0.3 microM), attenuated this NA-induced increase in [Ca2+]i and force, in a concentration-dependent manner. However, midazolam (10 and 30 microM), had no effect on the increases in [Ca2+]i and force induced by 10 mM caffeine. 5. In ryanodine-treated strips, which have functionally lost the NA-sensitive Ca2+ storage sites, NA slowly increased [Ca2+]i and force. Nicardipine (0.3 microM) did not modify the resting [Ca2+]i but partly attenuated the NA-induced increases in [Ca2+]i and force. In the presence of nicardipine, midazolam (100 microM) lowered the resting [Ca2+]i and further attenuated the remaining NA-induced increases in [Ca2+]i and force. 6. The [Ca2+]i-force relationship was obtained in ryanodine-treated strips by the application of ascending concentrations of Ca2+ (0.16-2.6 mM) in Ca2+-free solution containing 100 mM K+. NA (10 microM) shifted the [Ca2+]i-force relationship to the left and enhanced the maximum Ca2+-induced force. Under these conditions, whether in the presence or absence of 10 microM NA, midazolam (10 and 30 microM) attenuated the increases in [Ca2+]i and force induced by Ca2+ without changing the [Ca2+]i-force relationship. 7. It was concluded that, in smooth muscle of the rabbit mesenteric resistance artery, midazolam inhibits the NA-induced contraction through its inhibitory action on NA-induced Ca2+ mobilization. Midazolam attenuates NA-induced Ca2+ influx via its inhibition of both nicardipine-sensitive and -insensitive pathways. Furthermore, midazolam attenuates the NA-induced release of Ca2+ from the storage sites. This effect contributes to the midazolam-induced inhibition of the NA-induced phasic contraction.

Animals↗
PubMed1997

Vaginal atresia with transverse septum in a cat.

A six and half-year-old nulliparous mixed breed cat which had the complaints of vomiting, abdominal distention and depression was presented to the Veterinary Teaching Hospital of Osaka Prefecture University. She was suspected of pyometra by clinical signs and tests. By laparotomy, it was clarified that both uterine horns and vagina showed distension by the accumulation of secretions, and the vagina ended blindly leaving a tough connective tissue at the border between cranial and caudal part of the vagina. Postoperative contrast-radiograph of the remaining vagina proved it had no persistence of the hymen. From these findings, the condition was diagnosed as a feline atresia vaginalis with the transverse vaginal septum which is caused by the embryonic failure of canalization of the paramesonephric duct between the end of the Müllerian duct and the urogenital sinus.

Animals↗
PubMed1997

[Acute retrograde dissection of the aorta is a formidable complication in retrograde perfusion through the femoral artery].

To avoid this complication, we applied a Nelaton catheter (Imamura, Tokyo, Japan: standard type) as a guide to insert an arterial perfusion cannula (Bardic) into the femoral artery. Initially, the Nelaton catheter is accurately placed into the femoral artery through a purse string suture without applying vascular clamps on the artery or its branches. Then the perfusion cannula is advanced using the Nelaton catheter as a guide. We believe this procedure will avoid acute retrograde dissection of the aorta since it protects the femoral artery from injuries caused by the vascular clamps or the tip of the perfusion cannula.

Aortic Dissection↗
PubMed1996

Ligation of lateral carotid artery attenuates disturbance of brain function caused by subsequent cerebral ischemia in rabbits.

The effects of right carotid artery ligation on the subsequent cerebral ischemia, induced by iron particle injection, in rabbits, were evaluated by recording somatosensory evoked potentials (SEPs) and cerebral blood flow (CBF) using laser Doppler flowmetry. Iron particle injection decreased CBF over 120 min and delayed SEP onset latency in rabbits with no previous carotid artery ligation (control group). In rabbits with a carotid ligation 3 days before, iron particle injection induced the decrease of CBF, as in the control group, but did not prolong the latency of SEP. Injection of iron particles induced only a transient decrease of CBF (less than 10 min) followed by an abrupt recovery, and no prolongation of SEP latency was observed in rabbits with a carotid ligation 6 days before. These results suggest that carotid artery ligation induces a beneficial effect on cerebral function during the subsequent ischemia, which is independent on the CBF changes.

Animals↗