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Biomedical subjects

F Hayashi

Publications and source records attributed to F Hayashi.

At least 127 records · Page 7Linked to original sources
PubMed1992

Heterogeneity of the retinal G-protein transducin from frog rod photoreceptors. Biochemical identification and characterization of new subunits.

Transducin, a retinal G-protein, has been shown to exist as heterotrimers of alpha (39,000), beta (36,000), and gamma (approximately 7,000) subunits. Blue Sepharose CL-6B column chromatography of a transducin preparation extracted with a metal-free, low salt buffer containing GTP showed three distinct alpha and two distinct beta gamma activities in frog (Rana catesbeiana) rod outer segment. The binding of a hydrolysis-resistant GTP analog in these alpha fractions was proportional to the amount of the M(r) 39,000 protein. The first alpha was eluted in a complex with an inhibitory subunit of cGMP phosphodiesterase, but alpha subunits in the second and the third fractions were not complexed with any proteins. Two-dimensional gel electrophoresis and characterization with regard to the interaction with the inhibitory subunit of cGMP phosphodiesterase suggested that the first and the second alpha s were the same protein; however, the third alpha showed different characters as follows. We designated alpha in the first two fractions as alpha 1, and alpha in the third fraction as alpha 2. Nonlinear regression analysis for the binding of a hydrolysis-resistant GTP analog to both alpha subunits revealed a single class of GTP binding sites with an apparent stoichiometry of 1 mol of GTP/mol of alpha. Compared with alpha 1, alpha 2 required larger amounts of rhodopsin and beta gamma for the binding of a hydrolysis-resistant GTP analog. alpha 2 also showed less binding with the inhibitory subunit of cGMP phosphodiesterase. Both alpha 1 and alpha 2 complexed with beta gamma or beta delta (described below) were substrates for pertussis toxin-dependent ADP-ribosylation. The protein profiles of two beta gamma fractions revealed that the main fraction was composed of a beta gamma complex; however, the second active fraction was composed of beta complexed with delta (M(r) 12,000). Compared with beta gamma, beta delta stimulated GTP binding to alpha 1 at approximately 10-fold higher concentration. Two-dimensional gel electrophoresis revealed five beta and two gamma isoforms in beta gamma. Only one beta isoform was present in beta delta. The diversity of transducin subunits may reflect different signaling pathways in visual signal transduction.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1992

5-Hydroxytryptophan (5-HTP) augments spontaneous and evoked phrenic motoneuron discharge in spinalized rats.

Experiments on anesthetized, spinalized rats were conducted to determine the effects of systemic 5-hydroxytryptophan (5-HTP) administration on: (1) spontaneous phrenic nerve activity and (2) evoked phrenic responses to short latency, non-serotonergic synaptic inputs elicited by electrical stimulation of lateral funiculus. 5-HTP augmented spontaneous phrenic activity and allowed expression of a second, longer latency evoked response. Both effects were antagonized by methysergide. Our results suggest that spinal serotonin increases the efficacy of synaptic inputs to phrenic motoneurons.

5-Hydroxytryptophan↗
PubMed1992

Refilling the lens with a inflatable endocapsular balloon: surgical procedure in animal eyes.

In this report we describe the surgical details involved in refilling the lenses of 13 rabbit and 3 primate eyes using an inflatable endocapsular balloon to restore accommodation. The procedure involves endocapsular phacoemulsification through a small "buttonhole" or "dumbbell" anterior capsulotomy or minicircular capsulotomy and the simultaneous preservation of capsular integrity, including the zonules and ciliary muscles. An inflatable balloon made of thin silicone membrane is then inserted into the empty capsular bag. A liquid silicone polymer is injected into the balloon through a delivery tube, and the empty capsular bag is refilled by the inflated balloon. The procedure was found to be reproducible, and an accommodation of 6 D was confirmed in one primate eye. Capsular opacification occurred, but the proliferation and migration of residual lens epithelial cells could be hindered by abundant refilling. This lens-refilling technique may provide restoration of accommodation in future cataract surgery.

Accommodation, Ocular↗
PubMed1992

Extensive demyelinating changes in the peripheral nerves of Crow-Fukase syndrome: a pathological study of one autopsied case.

Pathological changes of the peripheral nervous system in one autopsied case of Crow-Fukase syndrome (POEMS syndrome) was systemically examined. Distally accentuated myelinated axon loss was observed in the peripheral nerve trunks, ventral and dorsal spinal roots, but was not observed in the fasciculus gracilis. Segmental demyelination and remyelination associated with focal excessive myelin outfolds were the most characteristic features, the distribution of which was more prominent in the proximal nerve trunks and the spinal nerve roots. Endoneurial edema was present, and focal perivascular T lymphocyte accumulation was occasionally observed in the spinal nerve roots and proximal nerve trunks. Neurons in the sympathetic ganglia, dorsal root ganglia and ventral horns were well preserved.

Aged↗
PubMed1992

The role of inhibitory amino acids in control of respiratory motor output in an arterially perfused rat.

The respiratory effects of drugs affecting GABAergic and glycinergic transmission were examined in order to assess the role of synaptic inhibition in breathing rhythmogenesis. Experiments were performed in the arterially perfused in situ brainstem-spinal cord preparation from adult rats (Hayashi et al., 1991, J. Neurosci. Meth. 36:63-70). Administration to the perfusate of agonists of GABAA, GABAB, and glycine receptors reduced both the frequency and amplitude of the activity recorded from the phrenic and hypoglossal nerves. Similar effects were observed following the infusion of aminooxyacetic acid (a blocker of GABA-transaminase). Picrotoxin (0.1-2 microM), bicuculline (0.05-0.2 microM), strychnine (0.1-1 microM) and phaclofen (0.1-0.2 mM) usually increased the frequency and amplitude of inspiratory bursts. Perfusion with low Cl- (8 mM) solution elicited tonic discharge followed by reversible arrest of the respiratory activity. It is concluded that synaptic inhibition is involved in the respiratory rhythm generation process in the mature mammalian brain. As data from the literature indicate that interference with central inhibitory processes does not largely affect the rhythm generation process in newborn rats, a possibility is discussed that the brainstem respiratory generator undergoes a developmental change from a 'pacemaker' driven circuit at the neonatal stage to a network requiring post-synaptic inhibition in the mature brain.

Amino Acids↗
PubMed1992

Depudecin: a novel compound inducing the flat phenotype of NIH3T3 cells doubly transformed by ras- and src-oncogene, produced by Alternaria brassicicola.

A novel compound depudecin inducing the flat phenotype of ras- and src- transformed NIH3T3 cells at a concentration of 1 microgram/ml was isolated from the culture broth of Alternaria brassicicola. Based on its spectroscopic characteristics and X-ray crystallographic analysis of its bis-(1S)-(-)-camphanate, the structure of depudecin was determined to be (2R,3S,4S,5E,7S,8S,9R)-2,9- dihydroxy-3,4;7,8-diepoxy-undeca-5,10-diene.

3T3 Cells↗
PubMed1992

[Involvement of the ventral horn cells in Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuritis].

The lumbar ventral horn cells and myelinated fibers in the ventral spinal roots of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuritis (CIDP) were morphometrically analyzed. In all six cases, central chromatolytic changes in the ventral horn cells were commonly observed. In addition, two out of four GBS cases and one of two CIDP cases showed a significant reduction in the ventral horn cell population, particularly in neurons with a large diameter. The cases with significant motoneuron loss also showed a remarkable reduction in the number of myelinated fibers in the ventral spinal roots, and severe axonal degeneration was observed in cases in acute phase. Astrogliosis of the ventral horn was also seen in some cases. The present study suggested that motoneuron loss in the primary demyelinating diseases like GBS and CIDP is the consequence of the axonal pathology of the motoneuron axons. These observations are helpful to understand motoneuron loss in certain motoneuron diseases with preferential involvement of lower motor neurons.

Adult↗
PubMed1992

[Effects of propentofylline (HWA285) on recovery of brain function following total cerebral ischemia (TCI) in dogs].

We examined the effects of a xanthine derivative, propentofylline, on recovery of brain function following TCI in 23 adult mongrel dogs. TCI was produced by clamping ascending aorta with aortoatrial bypass formation. The dogs were divided into 3 groups: preischemic administration (0.3 mg.kg-1.min-1, 30 min), post-ischemic administration (0.5 mg.kg-1.min-1, 6h) and control. The progress of recovery of EEG, respiration, reflexes, motor functions, arousal state and behavior were observed for 7 days after TCI and the latter 5 functions were analysed using neurologic deficit score (NDS). Propentofylline shortened the time necessary for reappearance of EEG after the starting of recirculation but could not improve the NDS.

Animals↗
PubMed1992

[Cytokine production by peripheral blood monocytes/macrophages in the patients with multiple sclerosis and its suppression by methylprednisolone].

The production of tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) by stimulated peripheral blood monocytes/macrophages (PBM) was assessed in patients with multiple sclerosis (MS), other neurological diseases (OND) or normal controls (NC) using enzyme-linked immunosorbent assay (ELISA). PBM obtained from acute phase of MS produced significantly higher amount of all these cytokines than those from chronic stable MS, OND or NC (TNF alpha, IL-1 alpha, IL-6: p less than 0.01, IL-1 beta: p less than 0.05). Methylprednisolone (MP) inhibited the lipopolysaccharide-induced cytokine production in a dose-dependent manner. These results suggest the possible roles of activated monocytes/macrophages in the acute exacervation of MS and suppressive effect of MP on cytokine production by activated monocytes/macrophages.

Adult↗
PubMed1991

Polymorphism in purified guanylate cyclase from vertebrate rod photoreceptors.

Guanylate cyclase from rod photoreceptors of amphibian (toad, Bufo marinus, and frog, Rana catesbeiana) and bovine retinas was solubilized and purified by a single chromatography step on a GTP-agarose column. Silver staining of purified amphibian enzymes in SDS/polyacrylamide gels disclosed a doublet band (110 and 115 kDa), while the bovine enzyme appeared as a singlet band (110 kDa). The identification of these guanylate cyclases was confirmed using three chromatography systems with the purified enzymes. Specific binding to Con A-Sepharose suggested that rod guanylate cyclase is a glycoprotein. Two-dimensional gel electrophoresis of purified toad, frog, and bovine enzymes resolved two, three, and five variants, respectively, that differed in isoelectric point. Two variants of toad guanylate cyclase showed differences in various characterizations. These data suggest multiple mechanisms for regulation of guanylate cyclase activity in vertebrate rod photoreceptors.

Animals↗
PubMed1991

Phosphatidylinositol-stimulated phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in vertebrate rod photoreceptors.

An inhibitory subunit (P gamma) of cGMP phosphodiesterase from vertebrate rod photoreceptors (frog, toad, and bovine) was phosphorylated by cytosolic protein kinase(s) derived from intact frog rod outer segments. The phosphorylation of frog P gamma was stimulated by phosphatidylinositol but not by cAMP or cGMP. One- and two-dimensional gel electrophoresis revealed that 70-80% of P gamma was phosphorylated with 1 mol of phosphate per frog P gamma under optimal conditions. A peptide that derived from an active domain of bovine P gamma was also phosphorylated. Phosphorylation of frog P gamma was inhibited by addition of the peptide to the reaction mixture. Phosphorylation of frog P gamma was also inhibited by addition of transducin subunits or active (P gamma-less) cGMP phosphodiesterase. Okadaic acid, on the other hand, enhanced P gamma phosphorylation, suggesting the presence of protein phosphatase(s) in the cytosolic fraction. These data suggest another mechanism for the regulation of cGMP phosphodiesterase in vertebrate rod photoreceptors.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1991

Malignant hemangiopericytoma of the liver: report of a case.

A 30 year old female was admitted with right upper abdominal pain and fever. Ultrasonography and computed tomography revealed a large cystic mass in the right lobe of the liver, and aspiration bacteriology was negative. A right hepatic lobectomy was performed for a suspected cystadenocarcinoma, however, the tumor was histologically diagnosed as a hemangiopericytoma with prominent venous invasion. The patient died within a short time of multiple pulmonary metastases. Primary hepatic hemangiopericytoma is extremely rare, and according to our research, this is only the 4th case reported in the literature.

Adult↗
PubMed1991

Respiratory patterns in anesthetised rats before and after anemic decerebration.

Experiments were undertaken to test the comparability of changes in respiratory frequency and tidal volume during hypoxia and hypercapnia in rats with and without intact peripheral chemoreceptors and with intact vagi. Neural organisation of respiratory control was perturbed by anemic decerebration, achieved by ligation of the common carotid and basilar arteries. Ischemia of the brain was produced as far candal as the rostral pontine nuclei involved in respiratory control but left the medulla well perfused. The dominant respiratory effect in animals breathing air or oxygen was polypnea with hypocapnia (mean PaCO2 when breathing air 24.7 mmHg, when breathing oxygen 29.6 mmHg). After decerebration the increase of ventilation produced by breathing 10% O2 in N2 was reduced compared with responses in the intact state but levels of ventilation (V1) in hypoxia were similar to those before decerebration. After decerebration, the increase of ventilation produced by breathing 5% CO2 was greatly reduced and the level of V1 in animals breathing CO2 was significantly less than in the intact state. Intermediate changes were seen in animals breathing 2-3% CO2 which converted the hypocapnia (PaCO2 30.9 mmHg) to eucapnia (PaCO2 46.4 mmHg). In the intact state, hypoxia dominantly caused increased frequency (f) and hypercapnia caused increased tidal volume (VT); after decerebration, hypoxia produced reduction of VT while hypercapnia produced reduction of f. Bilateral carotid sinus nerve section in decerebrate animals eliminated the ventilatory response to hypoxia but left the responses to hypercapnia unaltered. The results point to differences in the mechanisms by which hypoxia and hypercapnia influence respiration in both intact and decerebrate animals with carotid sinus and vagus nerves functional. The differences can now be interpreted in terms of specific neural features of respiratory control.

Anemia↗
PubMed1991

Intracellular recording from respiratory neurones in the perfused 'in situ' rat brain.

The study describes an arterially perfused in situ rat brain preparation, which uses an 'open circuit' flow of blood substitute with or without an oxygen carrier (2% perfluorotributylamine). The respiratory motor output was recorded from the phrenic and hypoglossal nerves, and could be maintained for up to 11 h from the start of perfusion (temperature of perfusate: 27-30 degrees C). The preparation allowed stable intracellular recordings from respiratory neurons in the brain stem and cervical spinal cord, and should be suitable for other studies which cannot be performed in standard whole animal models. The advantages of this approach compared with other in vitro or perfused in situ preparations are discussed.

Animals↗
PubMed1991

[Individual differences in image and pulse-wave responses elicited by listening to music].

This study was undertaken to clarify individual differences in psycho-physiological responses observed in subjects listening to music. Forty-five healthy females listened to the third movement of Mozart's "Eine Kleine Nachtmusik" via a biaural headphone at 69.4 dB(A) in Leq and 83.6 dB(A) in Lmax. This was undertaken twice with an interval of six days between sessions. Pulse-waves were recorded continuously before, during, and after listening by using a photoelectric plethysmograph. The psychological image each listener had of the music was measured immediately after listening by the SD method composed of fifteen scales with five rating points. The following results were obtained: 1) The pulse-wave height initially became low right after the onset of listening, though the degree of the decrement weakened in the second trial. Spectral analysis of pulse-waves revealed that the power percentage in the low frequency-bands below 0.3912 Hz grew markedly and that in the frequency-bands above 0.4238 Hz it dwindled during and after listening at the first trial. However, these changes of power percentage weakened in the second trial. 2) The image of the music being listened to changed significantly in 11 scales from the first trial to the second trial. 3) Subjects having a previous experience of listening to the music showed smaller image changes and responses in pulse-waves in the second trial than subjects having no such experience. 4) Previous experience of learning any music and the amount of contact with any music were not related to the image changes and pulse-wave responses in the second trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Characterization and classification of Actinobacillus (Haemophilus) pleuropneumoniae plasmids.

Actinobacillus (Haemophilus) pleuropneumoniae plasmids were characterized and classified. They were isolated from A pleuropneumoniae strains different in serotype, year isolated, or location from which isolated. Six of 8 plasmids encoded streptomycin (Sm) and sulfonamide (Su) resistance (SmSu). One of the other plasmids, pVM105, encoded ampicillin (Ap) resistance and another, pHM0, encoded no drug resistance. All SmSu plasmids were transferred to Escherichia coli strains by transformation. Among them, pABO and pMS260 were 8.1 kb and incompatible with each other; they were stable in E coli. The other SmSu plasmids, pHM1, pVM104, pVM106, and pKD25, were 4.3 kb and did not replicate stably in E coli. The former SmSu plasmids were mobilized in E coli strains by a plasmid RP4, which belonged to incompatibility (Inc) group P, but the latter plasmids were not. Further, each 8.1-kb SmSu plasmid and each 4.3-kb plasmid had the same respective restriction pattern. These results indicated that there were at least 2 types of SmSu plasmids in A pleuropneumoniae. The 2 types were classified in 2 groups: H1(pMS260 and pABO) and H2(pHM1, pVM104, pVM106, and pKD25). The H1 and H2 plasmids belonged to different Inc groups, and H2 plasmids belonged to a different Inc group from that of pHMO and pVM105.

Actinobacillus pleuropneumoniae↗
PubMed1991

[A case of hypereosinophilic syndrome associated with pulmonary infarction and hepatic vein obstruction (Budd-Chiari syndrome)].

A 21-year-old man was admitted in March 1987 with low grade fever and chest pain. Eosinophilia had been pointed out and PIE syndrome was diagnosed in another hospital a month before admission. Steroid therapy had been started. On the first admission, the chest roentgenogram showed bilateral pleural effusion and a nodular shadow in the left lower lung field. Open lung biopsy was performed and a diagnosis of pulmonary infarction was made. Eosinophilia, low grade fever and chest pain were improved by steroid therapy. He was discharged in April 1987. He was readmitted in September 1987 because of fever, back pain and abdominal distension. On the second admission, eosinophilia (4,510/mm3) was pointed out. The case was diagnosed as hepatic vein obstruction by hepatic vein angiography, liver biopsy and ultrasonic examination. He had transient remission on corticosteroid and anti-coagulant therapy. This case was considered as a rare case of hypereosinophilic syndrome associated with pulmonary infarction and Budd-Chiari syndrome.

Adult↗