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Y Kudo

Publications and source records attributed to Y Kudo.

At least 271 records · Page 15Linked to original sources
PubMed1990

Preparation and opioid activities of N-methylated analogs of [D-Ala2,Leu5]enkephalin.

Analogs of opioid pentapeptide [D-Ala2,Leu5]enkephalin were prepared using two kinds of N-methylation reactions, namely quaternization and amide-methylation. Quaternization reaction with CH3I-KHCO3 in methanol was applied to the deprotected N-terminal group of the pentapeptide derivatives affording trimethylammonium group-containing analogs. [Me3+Tyr1,D-Ala2,Leu5]enkephalin and its amide were found to show opioid activity on guinea pig ileium assay only slightly lower than the parent unmethylated peptides. Application of amide-methylation reaction using CH3I-Ag2O in DMF to the protected pentapeptide yielded a pentamethyl derivative in which all of the five N atoms were methylated. Deprotection of the derivative gave pentamethyl analogs of [D-Ala2,Leu5]enkephalin, which showed no significant activity on the guinea pig ileum assay and opiate-receptor binding assay.

Amino Acid Sequence↗
PubMed1990

Human placental L-tyrosine transport: a comparison of brush-border and basal membrane vesicles.

1. The mechanisms responsible for L-tyrosine transport at both the maternal-facing and fetal-facing surfaces of the human full-term placenta have been studied using isolated brush-border and basal membrane vesicles under conditions where a direct comparison of the transport properties of the two membranes can be made. 2. Brush-border vesicle uptake of L-tyrosine was substantially into an osmotically active space. Transport was Na(+)-independent, N-ethylmaleimide-sensitive (half-maximal inhibition, Ki = 1.1 mM), and insensitive to pH over the range 5.5-8.5. The initial rate of brush-border L-tyrosine uptake as a function of concentration showed saturation and obeyed Michaelis-Menten kinetics with Michaelis constant (Km) and maximum velocity (Vmax) values of 54.2 microM and 1.28 pmol (mg protein)-1 s-1, respectively. Influx of L-tyrosine was stereospecific and was virtually completely abolished by L-phenylalanine, L-tryptophan, L-leucine or by 2-aminobicycloheptane-2-carboxylic acid. These properties suggest that system L is responsible for brush-border L-tyrosine transport. 3. Basal membrane transport of L-tyrosine was more complex and uptake was slower than that found in the brush border. Although, as in the brush-border membranes, uptake was completely Na(+)-independent, N-ethylmaleimide was a less effective inhibitor, there was stimulation of transport at more alkaline pH and uptake did not show marked stereospecificity. An apparent Km of 168.9 microM and a Vmax of 0.31 pmol (mg protein)-1 s-1 were calculated for basal L-tyrosine transport. There was clear inhibition by L- and D-tyrosine, L-phenylalanine and L-tryptophan. 2-Aminobicycloheptane-2-carboxylic acid was not as effective. 4. These findings suggest the existence of non-identical carrier-mediated transport systems for L-tyrosine in brush-border and basal membranes. Brush-border transport resembles that by system L; L-tyrosine transport at the basal membrane may be via system t.

Amino Acids↗
PubMed1990

[Effects of vitamin E deficiency on bleomycin-induced pulmonary fibrosis in hamsters].

We examined the effect of free radicals on lung defense mechanism in bleomycin (BLM)-induced pulmonary fibrosis in hamsters. The concentration of vitamin E (VE) in the lung tissue increased significantly after intratracheal BLM administration. VE deficient hamsters showed increased lipid peroxide values in the lung tissue at a very early stage after BLM treatment. This was followed by decreased superoxide dismutase activities in the lung tissue. The results indicate that; 1) VE appears to be necessary for the prevention of lipid peroxidation in BLM-induced oxidant lung injury, 2) VE deficiency produces a large number of free radicals at the early stage after BLM treatment, and might induce protease-antiprotease imbalance within the lung, which probably causes an emphysematous change in the BLM-treated lung at a late stage after BLM administration.

Animals↗
PubMed1990

[A case of fibromuscular dysplasia presenting lateral medullary syndrome].

We reported a case of fibromuscular dysplasia (FMD) presenting lateral medullary syndrome accompanied with left truncal ataxia, left Horner's syndrome and superficial sensory deficit in the right extremities. He was 46-year-old man and had no remarkable risk factors for the cerebrovascular disease such as hypertension, diabetes mellitus and valvular heart disease. Cerebral angiography was performed and there was the string-of-beads-like shadow in the left vertebral artery, revealing a localized FMD. Wedge-shaped area of low signal intensity in the left lower medulla was recognized in magnetic resonance imaging (spin echo Tr/Te 600/30). It was suggested that the lesion of the lower medulla caused the patient's several symptoms. In Japan, there have been a few case reports of cervical or intracranial FMD, but we cannot find any report of FMD localizing in the unilateral vertebral artery. In general, it has been said that the etiology of lateral medullary syndrome under fifty years old differs from those of geriatric patients. The authors pointed out the significance of FMD as one of those risk factors causing lateral medullary syndrome and also discussed the mechanism of the sensory disturbance sparing face.

Arterial Occlusive Diseases↗
PubMed1989

Characterization of amino-acid transport systems in guinea-pig intestinal brush-border membrane.

The amino-acid transport systems have been characterized in brush-border membrane vesicles prepared from guinea-pig small intestine. Uptake of all amino acids tested was measured at the initial velocity for 5 s. L-Proline, alpha-(methylamino)isobutyrate, glycine, L-alanine and L-methionine were transported dependent solely on an Na+ gradient from the outside to the inside of the vesicles, and L-cysteine, L-phenylalanine and L-leucine were transported dependent largely on the Na+ gradient with a small fraction of Na+-independent transport. The transport of L-aspartic acid and L-lysine was independent of the Na+ gradient and L-lysine transport was somewhat inhibited by the presence of cations, including Na+, K+ and Li+. A cross-inhibition study of the uptake of these amino acids in the brush border of guinea-pig intestine revealed the presence of at least three Na+-dependent and three Na+-independent carrier-mediated systems. One Na+-dependent system interacted mainly with imino acid. Another Na+-dependent system interacted with neutral amino acids, while a third system was selective for glycine. One Na+-independent system is for acidic amino acids, another is responsible for neutral amino acids and a third for cationic amino acids. These transport systems of amino acids in guinea-pig small intestine are compared with those in rabbit and mouse intestine.

Amino Acids↗
PubMed1989

Three types of voltage-dependent calcium current in cultured rat hippocampal neurons.

Voltage-dependent calcium (Ca2+) currents in cultured rat hippocampal neurons were studied with the whole-cell recording mode of the patch-clamp technique. On the basis of the voltage-dependence of activation, kinetics of inactivation and pharmacology, 3 types of Ca2+ currents were distinguished. The low-threshold Ca2+ current (Il) was activated at -60 mV, and completely inactivated during a 100-ms depolarization to -40 mV (time constant: tau = 16 +/- 1 ms). The high-threshold currents (Ih), which were activated at -20 mV, could be separated into two types. The high-threshold, fast inactivating current (Ih,f) decayed quickly during a maintained depolarization (tau = 33 +/- 3 ms at 0 mV), whereas the high-threshold, slowly inactivating current (Ih,s) decayed with a much slower time constant (tau = 505 +/- 42 ms at 0 mV). The inactivations of Ih,f and Ih,s exhibited different time- and voltage-dependencies. Nickel ions (Ni2+, 25 microM) markedly suppressed Il, but little affected Ih. Cadmium ions (Cd2+, 10 microM) almost completely suppressed Ih, but left a small amount of Il. Lanthanum ions (La3+, 10 microM) almost completely suppressed both Il and Ih. Ih,s was sensitive to block by the dihydropyridine antagonist nicardipine (10 microM).

Animals↗
PubMed1989

Preparation and characterization of monoclonal antibodies against human myeloperoxidase.

We established 11 hybridomas producing monoclonal antibodies (MoAbs), designated AM, against human myeloperoxidase (MPO), by immunizing mice with the three forms of MPO (I, II, and III) purified from healthy human polymorphonuclear leukocytes (PMN) and characterized the specificity of the AM MoAbs. Ten of the AM MoAbs reacted similarly to each of the three forms using an enzyme-linked immunosorbent assay. When a cetyltrimethylammonium bromide (CETAB) extract of human PMN was electrophoresed in a CETAB polyacrylamide gel and transferred to a nitrocellulose filter, IgG1 class AM MoAbs immunostained only the MPO band of the proteins of the extract. In addition, the AM MoAbs reacted to two radioactive bands of 94 and 92 kDa in a HL-60 cell lysate labeled with [35S]methionine for 1 h. After a chase period of 24 h, these bands were replaced by four radioactive bands of 64.5, 43, 16.7, and 13.4 kDa, demonstrating that the MoAbs recognize not only mature MPO but also the MPO precursors of 94 and 92 kDa. The data also indicated that the two major bands of 64.5 and 13.4 kDa corresponded to heavy and light chains of mature MPO, respectively, and the additive intermediate bands of 43 and 16.7 kDa were MPO-related proteins. Moreover, AM MoAbs reacted to a similar extent to the deglycosylated form of MPO III with endo-beta-N-acetylglucosaminidase H (Endo-H). Thus, IgG1 class AM MoAbs recognized MPO with high specificity and reacted to the structure which is commonly conserved in the three mature forms of MPO (I, II, and III), MPO precursors, and deglycosylated MPO with Endo-H. AM MoAbs also specifically reacted to PMN and/or monocytes but did not react to lymphocytes when the cell staining method was used.

Animals↗
PubMed1989

An attempt to cause the selective loss of the cholinergic neurons in the basal forebrain of the rat: a new animal model of Alzheimer's disease.

In the present study, we attempted to develop a new animal model of Alzheimer's disease. Injections of a nerve growth factor (NGF)-diphtheria toxin conjugate into the cerebral cortex resulted in a marked ipsilateral reduction of cholinergic neurons in the horizontal limb of the diagonal band and basal magnocellular nucleus of rats. No effects could be seen in the cholinergic neurons located in the laterodorsal tegmental nucleus intrinsic cortical cholinergic neurons, and catecholaminergic locus coeruleus neurons. Injections of the conjugate into the caudoputamen failed to cause changes in the striatal cholinergic neurons. Since our method could selectively reduce cholinergic neurons in the basal forebrain without damage to the non-cholinergic neurons or passing fibers in this nucleus, this animal model method seems to be very useful in analyzing the pathogenesis of Alzheimer's disease or in examining the function of acetylcholine in the cholinergic neurons of the basal forebrain.

Alzheimer Disease↗
PubMed1989

Carrier-mediated transport system for cephalexin in human placental brush-border membrane vesicles.

The uptake of cephalosporin antibiotics, cephalexin, was studied with brush-border microvillous plasma membrane vesicles prepared and purified from human full-term placental syncytiotrophoblasts. The uptake of cephalexin by the membrane vesicles was not stimulated in the presence of an Na+ gradient from the outside to the inside of the vesicles, whereas alpha-(methylamino)isobutyrate uptake into the vesicles of the same preparation was stimulated by an Na+ gradient. The equilibrium level of cephalexin uptake decreased with increasing osmolarity of the medium, which indicates that cephalexin is transported into the membrane vesicles. When cephalexin concentrations were varied, the initial rate of uptake obeyed Michaelis-Menten kinetics with Km and Vmax values of 2.29 mM and 2.98 nmol/mg of protein per 60 s, respectively. The uptake of cephalexin was inhibited by structural analogues and sulfhydryl modifying reagents. These results indicate the existence of a carrier-mediated transport system for cephalexin in the human placental brush-border membranes.

Biological Transport, Active↗
PubMed1989

A new device for monitoring concentrations of intracellular Ca2+ in CNS preparations and its application to the frog's spinal cord.

For monitoring the changes in intracellular concentrations of Ca2+ in vertebrate CNS neurones in situ, we devised an assembly of two quartz-made optic fibres enclosed in a glass capillary. Esterified fluorescent Ca2+ indicator (quin2/AM) was injected into the motoneuronal pool of the frog's spinal cord, and about 60 min later, the assembly was inserted directly into the same region. Ultraviolet light for exciting the indicator was transmitted through one optic fibre, while the fluorescence emitted from the cells was guided to a photoelectric converter through the other fibre. Administration of Ringer's solution containing some stimulant (KCl, excitatory amino acids) through arterial perfusion, evoked both an increase of fluorescence intensity under excitation light of 340 nm wavelength and a decrease under 380 nm light. Electrical stimulation delivered to a dorsal root provoked equivalent responses in fluorescence; this response is known to be an indicator of an elevation in intracellular concentrations of Ca2+.

Aminoquinolines↗
PubMed1989

The use of an enzyme-linked immunosorbent assay for estimation of the immune status of chickens artificially immunized against coccidiosis.

Nine thousand commercial breeder chicks (Chankee) reared in a floor pen were exposed to restricted numbers of Eimeria tenella and E. necatrix oocysts to confer immunity. Antibody induction in these chicks was examined by the enzyme-linked immunosorbent assay (ELISA) with antigen prepared from E. tenella oocysts. The oocyst excretion pattern demonstrated recycled infections which continued in these chicks for greater than or equal to 22 days after exposure. Antibody levels in their sera, as determined by the mean absorbence values in ELISA, increased gradually up to 38 days post-inoculation. Mean absorbence values of sera from control chicks remained at a low level. When infected and control chicks were challenged with the two species of coccidia, the test chicks were protected against both species. The antibody level did not change for 8 days in the challenge groups, while in the control chicks, absorbence in ELISA rose significantly and the mean absorbence value was higher than that in immunized chicks. Some factors which influence the results of ELISA are considered and the applicability of this method to measuring immunity against coccidiosis in chickens is discussed.

Animals↗
PubMed1989

Pepsinogen secretion from cultured rat gastric mucosal cells.

Rat gastric mucosal cells were isolated with the aid of 0.1% collagenase and Dispase. Pepsinogen secretion from these cells was stimulated by carbachol, cholecystokinin octapeptide (CCK(S)-8) and pentagastrin, but not by histamine. Attempts to obtain a sufficient number of cells using a higher concentration of Dispase resulted in disappearance of the responses to secretagogues. However, when gastric mucosal cells thus prepared were cultured for 24 h in a CO2 incubator, they were found to respond not only to carbachol, CCK(S)-8 and pentagastrin, but also to histamine, resulting in an increase in pepsinogen secretion. The secretagogue-induced pepsinogen secretion was inhibited by its antagonist in a dose-dependent manner. These results suggest that the receptor present in chief cells for pepsinogen secretion was destroyed during the isolation procedure and regenerated during culture.

Animals↗
PubMed1989

Effects of afloqualone on vestibular nystagmus and the lateral vestibular nucleus.

To clarify the antivertiginous effect of afloqualone, an antispastic drug, we examined its action on the vestibular nervous system in cats. The results suggest that afloqualone inhibits vestibular nystagmus probably due to both inhibition of selective polysynaptic transmission and enhancement of the effects of GABA and glycine in the lateral vestibular nucleus (LVN), and its GABA-enhancing effect is thought to be attributable to the increased sensitivity of GABA receptors of the LVN neuron site.

Acetylcholine↗
PubMed1989

[Prevention of hepatitis B--HLA DR/DQ in HBs Ag nonresponder].

To evaluate the immunological background in HBs Ag nonresponders against hepatitis B vaccine, the lymphocyte surface marker and HLA-DR/DQ antigen were determined on hospital personnel, 70 males and 256 females, injected hepatitis B vaccine for three times. The vaccine made from the plasma of HBs Ag carriers was injected at the first and second vaccination and recombinant hepatitis B vaccine was injected at the third vaccination. A month after the third vaccination, blood was withdrawn for HBs antigen test by RIA. Border line cases (cut off index 1.0-1.9) are included in nonresponder (cut off index less than 0.9). Both nonresponders and low responders (cut off index 2-49) are more often seen in males than females and high responder (cut off index 50 or more) are seen more often in young females than males. Lymphocyte surface markers were studied by flow cytometry using the following monoclonal antibodies; OKT 3, 4, 8, DR, NK, Ia 1 and B7. No differences between lymphocyte surface markers of nonresponders and responders were noted. HLA-DR/DQ antigens were studied by the cytotoxicity test using Locus DR/DQ, Terasaki Second DR W-60 Tray and using following antibodies; DR 1, DR 2, DRW 15, DR 4, DR 5, DR 7, DR 9, DRW 10, DRW 8, DRW 12, DRW 13, DRW 6, DRW 52, DRW 53, DQW 1, DQW 6, DQW 2, DQW 3, DQW 7 and DQW 4. No significant differences between HLA-DR/DQ of nonresponders and responders were noted.

Adult↗
PubMed1989

[Experimental study on the dissecting aortic aneurysm].

Type I dissecting aortic aneurysm is not only the most common type of all but an extremely lethal event. It is important to create the experimental model of type I dissection for clarifying behavior of this disease and successful treatment. The purpose of this study is: (1) production of experimental model of type I aortic dissection; (2) examination of progression manner of dissection; (3) and investigation of influence of dissection upon aortic valve and coronary artery. The experimental model of type I aortic dissection was produced in adult mongrel dogs. Bilateral thoracotomy was made and intimal tear was created in the ascending aorta by modified Blanton's procedure. Hypertension and creation of large pocket of the aortic media were necessary to produce type I aortic dissection. Extension of dissection had a tendency toward the inner layer of the aortic wall at distal site. However, at proximal site the dissection progressed in the same layer of the aortic wall. In this series, retrograde extension of dissection remained blind above annulus of aortic valve, and no incidence of aortic regurgitation or coronary ischemia was occurred. But on histologic examination, degeneration of the aortic wall by the dissection was observed. Such weakness of aortic wall showed potentiality to developed into subsequent aortic regurgitation or coronary ischemia.

Aged↗
PubMed1989

[A case of acute idiopathic pandysautonomia].

A 19-year-old male student who complained of orthostatic syncope and low grade fever was admitted to our hospital and diagnosed acute idiopathic pandysautonomia (AIPD). He had dysesthesia and hypalgesia of his face and the upper part of the level of Th4, slight hypalgesia of the limbs and slightly exaggerated jaw jerk and diminished deep tendon reflexes of the limbs, but his main clinical manifestations were orthostatic hypotension (OH), sweating disturbance and alternative diarrhea and constipation. Paroxysmal cough and vomiting attack, severe weight loss and slight emotional change were also observed. There were no abnormal findings in the routine laboratory examinations, but the protein in the cerebrospinal fluid was slightly elevated in the initial state. The results of autonomic function tests, such as OH on tilting, no blood pressure effects on cold pressor test and hand grip test, no overshoot in Valsalva maneuver, low norepinephrine (NE) level at resting and poor NE response on tilting, exaggerated response to a small dose of NE infusion (denervation supersensitivity), suggested that the sympathetic post-ganglionic sites were chiefly affected. The parasympathetic nervous functions were seemed to be almost intact by the results of Aschner test, Czermak test and coefficient variation of R-R intervals. Sural nerve biopsy revealed a marked loss of small myelinated and unmyelinated fibers, suggesting axonal degeneration. These findings were different from those of the Guillain-Barré syndrome (GBS), although the allergic or immunological mechanisms are suggested as the cause of both AIPD and GBS. In this case, amezinium metilsulfate, an indirect sympathomimetic agent, was most effective to OH and cough attack.

Acute Disease↗
PubMed1988

Stimulation of muscarinic receptor in hippocampal neuron induces characteristic increase in cytosolic free Ca2+ concentration.

Changes in cytosolic free Ca2+ concentration ([Ca2+]i) in response to acetylcholine (ACh) were examined by fura-2 fluorometry in cultured rat hippocampal neurons. ACh (greater than or equal to 10(-5) M) induced an increase in [Ca2+]i composed of fast transient and slow long-lasting phases. Atropine (10(-8) M) abolished the fast component and greatly reduced the slow component. The slow component was selectively blocked by pirenzepine (10(-6) M). The effect of ACh remained partially in a Ca2+-deficient medium where effects of L-glutamate and KCl (50 mM) were abolished. Present results suggest that ACh elevates [Ca2+]i by activation of muscarinic receptor subtypes, one of which is coupled with ion channels and the other of which transduces the ACh binding to mobilization of intracellularly stored Ca2+.

Acetylcholine↗