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Y Harada

Publications and source records attributed to Y Harada.

At least 253 records · Page 14Linked to original sources
PubMed1996

Specificity and development of innervation pattern of Xenopus pectoralis muscle.

Multielectrode recordings were used to identify and measure the axonal inputs to each end plate on contiguous surface fibers covering about 25% of the Xenopus pectoralis muscle in mature and developing animals. The mature innervation pattern was remarkably precise. Individual axons tended to innervate fibers of similar input resistance (R(in)) in compact motor units restricted to only a portion of the region studied. Motor units comprising fibers of similar R(in) overlapped mainly near their borders. Most fibers had two end plates. In more than 80% of these fibers, both end plates received input from the same axon. In 57%, this was the only input to both end plates. This implies a powerful mechanism for excluding or eliminating inputs from other axons. About 16% of the mature junctions showed focal polyneuronal innervation, with the weaker end plate potential component often less than 1 mV in noncurarized preparation. However, we have no evidence that the weaker inputs were being eliminated. During development, motor units became more compact, which was associated with synapse elimination; but from the earliest times studied, soon after metamorphosis when many fibers were adding second end plates, a majority of those that had two end plates were innervated at both sites by the same axon.

Aging↗
PubMed1996

Regeneration of specific innervation in Xenopus pectoralis muscle.

We investigated the motor unit organization and precision of reinnervation in the Xenopus pectoralis muscle following different manipulations, including crush or section of the posterior pectoralis nerve, foreign nerve innervation, and crush coupled with activity modulation or block. Most fibers have two neuromuscular junctions, and multielectrode recordings were used to identify the axonal origin of all inputs to both junctions on most or all fibers covering about 25% of the muscle surface. Following simple nerve crush, a highly organized innervation pattern was restored, indistinguishable from the normal pattern, including selective innervation of fibers of similar input resistance (R(in)), compact motor unit organization, and high incidence of exclusive innervation of both end plates on each fiber by the same axon (distributed mononeuronal innervation, or a/a pattern). Initial reinnervation was equally precise when nerve conduction in the regenerating nerve was blocked by tetrodotoxin. More distant or repeated nerve crush or nerve section delayed and reduced the precision of reinnervation, but the majority of fibers still received input to both end plates by the same axon, often in combination with others. A foreign nerve, the pectoralis sternalis, which in its own muscle forms only single end plates, showed less precise reinnervation, but still had an incidence of a/a innervation far above chance. These data imply the expression and recognition of remarkably precise chemospecific cues even in mature animals, superimposed on which is a further refinement by synapse elimination, probably based on an activity-dependent process.

Animals↗
PubMed1996

Meckel's cartilage chondrocytes in organ culture synthesize bone-type proteins accompanying osteocytic phenotype expression.

We examined whether Meckel's cartilage of embryonic mice, 17 days in utero, undergo the cellular transformation into the osteocyte-like phenotype under organ culture conditions. Explants were grown by our original pithole method modified Trowell-type cultures for up to 4 weeks at 37 degrees C under 5% CO2 in air. Specimens were examined using histological procedures including immunostaining and electron microscopy. In addition, the effects of beta-glycerophosphate on matrix calcification were also examined in cultures with or without beta-glycerophosphate. Addition of beta-glycerophosphate induced calcification at a higher level, but calcium mineral deposition occurred regardless of the addition of beta-glycerophosphate to the culture medium. Light and electron microscopic analyses showed that freshly isolated chondrocytes prior to cell culture had typical hypertrophic morphology, but shortly after commencement of culture, they showed morphological modifications. The cells showing chondrocytic phenotypes became basophilic elliptical cells, and eventually transformed into flattened osteocyte-like cells. Bone-like features for cellular elements were characterized by spindle-shaped cells with elongated processes accompanying bone-specific thick-banded collagen fibrils. Immunostaining showed that at 2 weeks in culture, type I and type II collagens coexisted in the matrix, but subsequently type II collagen synthesis ceased and was replaced by type I collagen synthesis. Immunofluorescent labeling for osteocalcin was noted first in the peripheral cells by 1 week, but at 3 weeks this reaction spread to the central zone in explants. Alkaline phosphatase activity (ALPase) was expressed on the cells in the central zone prior to calcium mineral deposition as shown by von Kossa's reaction at 3 weeks in culture. These results showed that Meckel's cartilage chondrocytes in organ culture synthesize bone-type proteins accompanying osteocytic phenotype expression.

Alkaline Phosphatase↗
PubMed1996

Intraabdominal contamination after gallbladder perforation during laparoscopic cholecystectomy and its complications.

BACKGROUND: Gallbladder perforation often occurs during laparoscopic cholecystectomy. METHODS: The frequency and causes of gallbladder perforation as well as the relevant clinical background factors were investigated in 110 patients undergoing laparoscopic cholecystectomy. We also evaluated intraperitoneal contamination by bacteria and gallstones at the time of gallbladder perforation and investigated whether perforation caused early or late postoperative complications. RESULTS: Intraoperative gallbladder perforation occurred in 29 of the 110 patients (26.3%). It was caused by injury with an electric knife during dissection of the gallbladder bed, injury during gallbladder retraction with grasping forceps, injury during gallbladder extraction from the abdomen, and slippage of cystic duct clips (potentially causing bile and stone spillage). Perforation was more frequent in patients with positive bile cultures and in those with pigment stones (p < 0.02), but not in patients with cholecystitis or cystic duct obstruction. The peritoneal cavity was contaminated by bacteria in 11/29 patients (37.9%) and by spilled stones in 3/29 patients (10.3%). There was no difference in the incidence of postoperative complications between the patients with and without perforation either in the early postoperative period or during follow-up for 24-42 months. Only one patient developed abdominal pain and fever in the early postoperative period, and they were probably related to perforation. CONCLUSIONS: Although gallbladder perforation is sometimes unavoidable during laparoscopic cholecystectomy, the risk of severe complications appears to be minimized by early closure of perforation, retrieval of as many of the spilled stones as possible, and intraperitoneal lavage.

Cholecystectomy, Laparoscopic↗
PubMed1996

Increased migration of neutrophils to granulocyte-colony stimulating factor in rat carrageenin-induced pleurisy: roles of complement, bradykinin, and inducible cyclooxygenase-2.

Administration of human recombinant granulocyte colony-stimulating factor (G-CSF, 100 micrograms/kg/day, s.c) to rats for 4 days significantly increased circulating neutrophil counts (by 1130%), together with an increase in mononuclear leukocyte counts (by 119%). Infiltrated pleural neutrophil counts in G-CSF-treated rats (G-CSF-r) 5 h after the intrapleural injection of zymosan-activated serum were significantly higher (by 155%) than those in control rats (Vehicle-r). In carrageenin-induced pleurisy, counts of infiltrated pleural neutrophils in G-CSF-r 5 and 7 h after carrageenin were significantly higher (by 119% and 116%) than those in Vehicle-r. G-CSF treatment increased the volume of pleural exudate and the plasma exudation rate by 122% and 226%, compared to values in Vehicle-r 5 h after carrageenin. Cobra venom factor (75 micrograms/kg, i.v.) significantly reduced pleural neutrophil migration in G-CSF-r (by 53%) and Vehicle-r (by 49%). Bromelain (10 mg/kg, i.v.) and aspirin (100 mg/kg, p.o.) reduced pleural neutrophil migration and reduced exudate volume and plasma exudation. Intrapleural bradykinin-(1-5) and prostaglandin E2 levels were significantly higher in G-CSF-r than in Vehicle-r. The increased neutrophil migration in G-CSF-r may be attributed to enhanced activation of the complement system facilitated by increased plasma exudation due to bradykinin and prostaglandins.

Animals↗
PubMed1996

Therapeutic effect of secretin in patients with jaundice; double-blind placebo-controlled multicentric trial.

Secretin, a gastrointestinal hormone, has been shown to have a potent choleretic effect. Having already obtained some beneficial effects with secretin in patients with intrahepatic cholestasis, we sought to confirm its effects in a double-blind placebo-controlled study in patients with mild jaundice after acute or during chronic hepatitis, where total bilirubin level was in excess of 4.0 mg/dl for 3 days or more. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and familiar hyperbilirubinemia were excluded from the study. Ninety-three patients were included in this analysis, but the final evaluation covered 69 of them. No statistically significant differences were found in the reduction of serum bilirubin levels between secretin and placebo groups. As a number of patients with liver cirrhosis had been included, the subjects were subdivided into one group with cholestasis in hepatitis and one with liver cirrhosis. In the subgroup of cirrhotic patients who received secretin, serum levels of AST were significantly increased compared with the placebo group. However, since the choleretic effect of secretin is unique, further studies seem to be warranted.

Adolescent↗
PubMed1996

Role of prostaglandin H synthase-2 in prostaglandin E2 formation in rat carrageenin-induced pleurisy.

Rat carrageenin-induced pleurisy was used to clarify the role of prostaglandin H synthase (PGHS)-2 in acute inflammation. Intrapleural injection of 0.2 ml of 2% lambda-carrageenin induced accumulation of exudate and infiltration of leukocytes into the pleural cavity. When PGHS-1 and -2 proteins in the pleural exudate cells were analyzed by Western blot analysis, PGHS-2 was detectable from 1 hr after carrageenin injection. Its level rose sharply, remained high from 3 to 7 hr after injection, and then fell to near the detection limit. PGHS-1 was also detected, but kept almost the same level throughout the course of the pleurisy. Levels of prostaglandin (PG) E2 and thromboxane (TX) B2 in the exudate increased from hour 3 to hour 7, and then declined. Thus, the changes of the level of PGE2 were closely paralleled those of PGHS-2. The selective PGHS-2 inhibitors NS-398, nimesulide and SC-58125 suppressed the inflammatory reaction and caused a marked decrease in the level of PGE2 but not in those of TXB2 and 6-keto-PGF 1 alpha. These results suggest that the PGHS-2 expressed in the pleural exudate cells may be involved in PGE2 formation at the site of inflammation.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

Direct inhibition of the actomyosin motility by local anesthetics in vitro.

Using a recently developed in vitro motility assay, we have demonstrated that local anesthetics directly inhibit myosin-based movement of single actin filaments in a reversible dose-dependent manner. This is the first reported account of the actions of local anesthetics on purified proteins at the molecular level. In this study, two tertiary amine local anesthetics, lidocaine and tetracaine, were used. The inhibitory action of the local anesthetics on actomyosin sliding movement was pH dependent; the anesthetics were more potent at higher pH values, and this reaction was accompanied by an increased proportion of the uncharged form of the anesthetics. QX-314, a permanently charged derivative of lidocaine, had no effect on actomyosin sliding movement. These results indicate that the uncharged form of local anesthetics is predominantly responsible for the inhibition of actomyosin sliding movement. The local anesthetics inhibited sliding movement but hardly interfered with the binding of actin filaments to myosin on the surface or with actomyosin ATPase activity at low ionic strength. To characterize the actomyosin interaction in the presence of anesthetics, we measured the binding and breaking force of the actomyosin complex. The binding of actin filaments to myosin on the surface was not affected by lidocaine at low ionic strength. The breaking force, measured using optical tweezers, was approximately 1.5 pN per micron of an actin filament, which was much smaller than in rigor and isometric force. The binding and breaking force greatly decreased with increasing ionic strength, indicating that the remaining interaction is ionic in nature. The result suggests that the binding and ATPase of actomyosin are governed predominantly by ionic interaction, which is hardly affected by anesthetics; whereas the force generation requires hydrophobic interaction, which plays a major part of the strong binding and is blocked by anesthetics, in addition to the ionic interaction.

Actins↗
PubMed1996

Multiple- and single-molecule analysis of the actomyosin motor by nanometer-piconewton manipulation with a microneedle: unitary steps and forces.

We have developed a new technique for measurements of piconewton forces and nanometer displacements in the millisecond time range caused by actin-myosin interaction in vitro by manipulating single actin filaments with a glass microneedle. Here, we describe in full the details of this method. Using this method, the elementary events in energy transduction by the actomyosin motor, driven by ATP hydrolysis, were directly recorded from multiple and single molecules. We found that not only the velocity but also the force greatly depended on the orientations of myosin relative to the actin filament axis. Therefore, to avoid the effects of random orientation of myosin and association of myosin with an artificial substrate in the surface motility assay, we measured forces and displacements by myosin molecules correctly oriented in single synthetic myosin rod cofilaments. At a high myosin-to-rod ratio, large force fluctuations were observed when the actin filament interacted in the correct orientation with a cofilament. The noise analysis of the force fluctuations caused by a small number of heads showed that the myosin head generated a force of 5.9 +/- 0.8 pN at peak and 2.1 +/- 0.4 pN on average over the whole ATPase cycle. The rate constants for transitions into (k+) and out of (k-) the force generation state and the duty ratio were 12 +/- 2 s-1, and 22 +/- 4 s-1, and 0.36 +/- 0.07, respectively. The stiffness was 0.14 pN nm-1 head-1 for slow length change (100 Hz), which would be approximately 0.28 pN nm-1 head-1 for rapid length change or in rigor. At a very low myosin-to-rod ratio, distinct actomyosin attachment, force generation (the power stroke), and detachment events were directly detected. At high load, one power stroke generated a force spike with a peak value of 5-6 pN and a duration of 50 ms (k(-)-1), which were compatible with those of individual myosin heads deduced from the force fluctuations. As the load was reduced, the force of the power stroke decreased and the needle displacement increased. At near zero load, the mean size of single displacement spikes, i.e., the unitary steps caused by correctly oriented myosin, which were corrected for the stiffness of the needle-to-myosin linkage and the randomizing effect by the thermal vibration of the needle, was approximately 20 nm.

Actomyosin↗
PubMed1996

Factors affecting the cytokine production of human T cells stimulated by different modes of activation.

According to the widely accepted classification, human TH cell clones can be divided into two mutually exclusive subsets, TH1 and TH2, based on their profile of cytokine production. The intracellular difference between these clones is not clear. To characterize the biochemical nature of T-cell receptor (TCR)/CD3 complex-mediated signal transduction pathways, we introduced several human TH cell clones of THO- or TH1-like phenotype and analyzed the effects of various drugs and antibodies on cytokine production or proliferation of these clones. The tyrosine kinase inhibitor herbimycin inhibited the production of interferon-gamma (IFN-gamma) by THO-like clone, after stimulation with anti-CD3 monoclonal antibody alpha CD3-mAb) or with phorbol 12-myristate 13-acetate (PMA) and the calcium ionophore A23187. However, whereas herbimycin strongly inhibited the production of IL-4 and IL-5 by alpha CD3 mAb stimulated T cells, it did not affect the production of these cytokines after PMA/A23187 stimulation. Cyclosporin A inhibited the proliferation as well as the production of the cytokines, including that of IL-2, IL-4, IL-5, and IFN-gamma, irrespective of the mode of stimulation. A23187, which synergizes with PMA in the induction of IL-4 and IFN-gamma, inhibited PMA-induced IL-10 production in a dose-dependent manner. Transforming growth factor-beta and anti-IL-2 receptor monoclonal antibody partially inhibited alpha CD3 mAb-mediated T-cell proliferation, but had no effect on the proliferation induced by PMA and A23187. Cyclic adenosine monophosphate (cAMP)-elevating drugs, like prostaglandin E2 and dibutyryl cAMP, inhibited the TCR-mediated cytokine production but shifted the cytokine production profile from a TH0 to a TH2 type after stimulation with PMA and A23187. Finally, we analyzed the induction of activity of two transcription factors, nuclear factor-kappa B (NF-kappa B) and nuclear factor of activated T cells, involved in the regulation of cytokine gene expression, after a different mode of activation. The induction of NF-kappa B (p50/p65 heterodimer) by using alpha CD3-mAb stimulation but not by using PMA/A23187 stimulation was found to be inhibited by using cAMP-elevating drugs.

Antibodies, Monoclonal↗
PubMed1996

Spatial expression of a forkhead homologue in the sea urchin embryo.

Echinoderms are the sister group of the chordates and hemichordates within the deuterostomes. They lack a notochord or any structures obviously homologous with it. To gain insight into developmental mechanisms important in the origin and early evolution of chordates, we investigated sea urchin homologues of chordate genes that are implicated in notochord formation, viz. Brachyury and HNF-3 beta. Here we report the pattern of expression of a sea urchin orthologue of forkhead, Hphnf3 which is present as a single copy per haploid genome. An Hphnf3 transcript of 3.0 kb was first detected at the swimming blastula stage, accumulated maximally at the gastrula and prism-embryo stages, and decreased at the pluteus-larva stage. In situ hybridization signals were found in cells of the vegetal plate of the swimming blastula. During gastrulation, intense staining was evident in the cells surrounding the blastopore, whereas weak staining was detected in the invaginating archenteron. At the prism-embryo stage, the entire archenteron stained intensely; then, at pluteus stage, the larva staining decreased in intensity. The forkhead and Brachyury genes begin to be expressed almost simultaneously in sea urchin embryos, in the vegetal plate at the late blastula stage. After the onset of gastrulation, however, Hphnf3 is expressed in the posterior part of the archenteron, whereas the Brachyury orthologue, HpTa, is expressed in the secondary mesenchyme founder cells, which occupy the anterior tip of archenteron. Hphnf3 may contribute to specification of embryonic cells as archenteron, and the role of HpTa may be directed towards specification of mesodermal founder cells. Except for the basal character of expression in endoderm and endomesoderm, these transcription factors are clearly utilized differently in chordates.

Amino Acid Sequence↗
PubMed1996

Identification of early plasma cells in peripheral blood and their clinical significance.

In the peripheral blood (PB) we detected so-called early plasma cells that might already be committed to entering the bone marrow (BM). By two-colour staining with FITC-anti-CD38 antibody, their intensity (CD38++) of expression of CD38 antigen was between that of germinal centre (GC) B cells (low expression (CD38+)) and that of BM plasma cells (high expression (CD38++)), and their phenotype was CD38++ CD19+ CD10- CD20- CD21+ CD24- CD39+ CD5- VLA-4+ VLA-5- MPC-1- without expression of surface membrane IgM (SmIgM). Morphological and immunological examination of the sorted cells confirmed that they were plasmacytoid cells with expression of cytoplasmic IgG (cIgG). Variations of these early plasma cells were examined in various diseases. In active systemic lupus erythematosus, bacterial septicaemia and liver cirrhosis, early plasma cell levels were significantly increased in PB, and after subsidence of such inflammation (inactive states) these cells returned to normal levels. In contrast, normal early plasma cells were significantly suppressed in myelomas, whilst normal or slightly increased numbers of early plasma cells was found in benign monoclonal gammopathy (BMG). In addition, the number of normal early plasma cells returned to a normal level in myeloma cases with complete responses. Therefore, early plasma cells were identified phenotypically, and an increase and decrease in these cells in PB may reflect mobilization and suppression, respectively, of activated B cells into BM plasma cells.

ADP-ribosyl Cyclase↗
PubMed1996

Synthesis of secretory protein in regenerating liver of rat after partial hepatectomy.

Albumin immunoreactivity in the liver was examined on days 2, 5 and 10 after two-thirds partial hepatectomy by light and ultrastructural immunoperoxidase methods and the ultrastructural area of the rough endoplasmic reticulum (ER) in hepatocytes was measured. Albumin immunoreactivity was seen in the rough ER and Golgi apparatus of all hepatocytes in the hepatectomized liver and ultrastructural analysis showed a significantly greater area of rough ER on day 5 than on days 2 or 10. Albumin mRNA was studied by the in situ hybridization technique using radioisotopes and their numbers were determined visually. Albumin mRNA was present as grains in all hepatocytes and the grains varied in number during regeneration of the liver, being more abundant on day 5 than on days 2 or 10. The activity of [3H]-leucine incorporated into albumin synthesis, an indicator of translational activity, was higher on days 5 and 10 than on day 2 and was highest on day 5. In conclusion, albumin synthesis varied during liver regeneration after partial hepatectomy, being reduced at the peak of cell proliferation on day 2 and being most active on day 5.

Albumins↗
PubMed1996

Inhibitors of cytochrome P-450 augment fever induced by interleukin-1 beta.

Metabolites of cytochrome P-450 are produced in cells when arachidonic acid cascade is activated. Fever genesis depends largely on the cyclooxygenase branch of arachidonic acid cascade, which is caused by many stimuli, such as interleukin (IL)-1, IL-6, and interferon-alpha. To assess the significance of cytochrome P-450 branch in fever, murine recombinant IL-1 beta was bilaterally microinjected (1 ng/microliter) into the medial preoptic area and anterior hypothalamus in conscious rats treated 60 min previously with or without the cytochrome P-450 inhibitor econazole (15 mg/kg im). The IL-1 beta-induced rise in colonic temperature was enhanced after the plateau phase of fever (from 240 min after IL-1 beta) in econazole-pretreated rats (P < 0.001). Another cytochrome P-450 inhibitor, clotrimazole (15 mg/kg im), also enhanced IL-1 beta-induced fever from 160 min after IL-1 beta injection (P < 0.001). Econazole also enhanced the fever when it was given 120 min before injection of IL-1 beta (P < 0.001). The cytochrome P-450 inhibitor, however, did not affect the fever when given 10 min after IL-1 beta (P = 0.95). Econazole and clotrimazole did not alter normal body temperature (P = 0.65 and 0.73, respectively). The results suggest that the metabolite(s) of cytochrome P-450 affect the falling phase after the plateau phase of fever and act as putative endogenous antipyretic(s).

Animals↗
PubMed1996

Characterization of a new breast cancer-associated antigen and its relationship to MUC1 and TAG-72 antigens.

We have characterized a new tumor-associated antigen defined by monoclonal antibody (MAb) generated against HMA-1 breast cancer cell line. MAb AM-1 was selected based on its preferential reactivity to breast cancer cells versus to normal or benign epithelial cells by immunofluorescence and immunohistochemical assays of cultured, or fresh specimens. AM-1 demonstrated strong reactivity to breast cancer cell lines including HMA-1, YMB-1-E, YMB-1 and MDA-MB-231 in flow cytometry. In immunoprecipitation, AM-1 recognized high molecular weight components of 160-210 kDa and > 370 kDa. Reactivity with HMA-1 cells was diminished markedly when treated by heat, protease or periodate, suggesting that the antigenic epitope is composed with carbohydrates and peptides. Enzyme digestion of precipitated antigens demonstrated that the antigen contains O-linked and N-linked carbohydrates with neuraminic acid structures. Furthermore, binding inhibition and sandwich ELISA assays using MAbs reactive with known breast cancer-associated antigens and synthetic MUC1 core peptide (PDTRPAPGSTAPPAHGVTSAPDTR) demonstrated that the antigen is distinct from CEA, TAG-72 or MUC1, while the antigen conjoins with MUC1 and TAG-72 as a trimmer form in HMA-1 cells. These results suggest that AM-1 recognizes a novel glycoprotein which is abundant in breast cancer, and may be utilized in the management of breast cancer patients.

Adenocarcinoma↗
PubMed1996

Spinal schwannomas: a review of 42 cases.

In this study, 42 cases of spinal schwannomas are reviewed. We analyzed the therapeutic results of patients with spinal schwannomas in order to investigate the factors which affect the clinical outcomes. Early diagnosis and treatment could help procure a good result for the patient. The delay in diagnosis and the subsequent duration of symptoms was significantly longer in cases of lumbar lesions compared to cervical and thoracic lesions. Tumor recurrence was rare, but in some cases where complete resection was not possible, close follow-up of the patients postoperatively with MRI was indicated.

Adolescent↗
PubMed1996

Surgical treatment for metastatic tumors of the spine.

We report herein the results of anterior or posterior neural decompression with spinal stabilization in 16 patients with spinal metastases. Intractable back pain was relieved in 14 patients (87.5%) and 4 had complete pain relief. Neurologic recovery was observed in 8 out of 13 patients (61.5%) who had some neurologic deficits before surgery. The activities of daily living improved in 7 of 9 (77.7%), and 5 out of 8 patients (62.5%) who had been unable to walk before surgery became ambulatory after surgery. The average operation time was 3h 15 min with an average blood loss of 2150 ml. No patient died within 1 month after surgery and the median survival was 19.1 months. The results indicated that, if properly indicated, anterior or posterior neural decompression and spinal stabilization is a safe and effective treatment for patients with spinal metastases to improve the quality of life for the patients' remaining years.

Adolescent↗