F1-ATPase: a rotary motor made of a single molecule.
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Binding Sites↗
Biomedical subjects
M Yoshida
Publications and source records attributed to M Yoshida.
Physical and serologic examinations of foals at 30 and 45 days of age for early diagnosis of Rhodococcus equi infection on endemically infected farms.
OBJECTIVE: To evaluate results of physical and serologic examinations of foals at 30 and 45 days of age on 3 types of farms with various prevalences of clinical disease (endemic, sporadic, none) caused by Rhodococcus equi and to determine whether evaluations were helpful in early diagnosis and control of the disease. DESIGN: Prospective cohort study. ANIMALS: 144 foals at 30 and 45 days of age. PROCEDURE: During a 2-year period, 36 foals on farms at which R equi infection was endemic, 71 foals on farms at which the disease was sporadically detected, and 37 foals on farms without the disease were examined by means of auscultation of lungs, serum biochemical and hematologic analyses, and determination of antibody titers against R equi, using ELISA. Transtracheal aspirates were obtained from 14 of 32 foals that had clinical signs of disease and 7 of 41 seropositive foals that did not have clinical signs of disease. RESULTS: Prevalences of respiratory tract disease and seropositive conversion rates for 45-day-old foals on endemically and sporadically infected farms were significantly higher than on farms without the disease. Rhodococcus equi was isolated from tracheal aspirates of seropositive foals, even when clinical signs were not evident. CLINICAL IMPLICATIONS: Physical and serologic examinations of foals at 30 and 45 days of age were useful for early diagnosis of R equi infection, especially for foals on farms at which the disease was endemic.
Actinomycetales Infections↗
Conversion of Amadori product of Maillard reaction to Nepsilon-(carboxymethyl)lysine in alkaline condition.
Nepsilon-(carboxymethyl)lysine (CML) is known to be formed by oxidative cleavage of Amadori products between C-2 and C-3 of the carbohydrate chain. We report here that CML formation from Amadori compounds is highly accelerated under alkaline conditions. Incubation of glycated human serum albumin (HSA) in 0.1 N NaOH led to the formation of CML whereas glycated HSA reduced by NaCNBH3 or non-glycated HSA did not generate CML. Nalpha-t-butyloxycarbonyl-Nepsilon-fructoselysine (Boc-FL), a model compound of Amadori product, was converted to CML under alkaline conditions. CML level of human sera (n=224) preincubated with 0.1 N NaOH correlated well with glycated albumin value (r=0.912) and hemoglobin A1c (r=0.797).
Amino Acids↗
Development of an assay for bioactive insulin.
A method to detect the biological activity of serum insulin has been developed. This method, called a bioactive insulin assay, determines the ability of serum insulin to stimulate the autophosphorylation of insulin receptors in an intact cell system. For this, intact Chinese hamster ovary cells which overexpress the human insulin receptor are treated with serum and then lysed. Autophosphorylation of the insulin receptors is then measured by a two-site immunofluorometric assay using monoclonal anti-insulin receptor antibodies and europium-labeled anti-phosphotyrosine antibodies. The detection limit of this assay is 1 microU/ml of insulin. Dilution and recovery test inter- and intraassay coefficient variations are permissible. The amount of insulin determined by this assay correlated well with the amount of insulin detected by a traditional immunological assay for insulin (r = 0.94, P < 0.001). In the case of a mutant insulin, the insulin from a Wakayama subject, the biologically active insulin was found to constitute 9% of the immunologically reactive insulin. Since this assay specifically measures the amount of biologically active insulin present in serum, it should be particularly useful in monitoring active insulin in patients with various mutant insulins.
Animals↗
The gene structure and promoter sequence of mouse hyaluronan synthase 1.
The structure and organization of mouse hyaluronan synthase 1 gene, HAS1 were determined by direct sequencing of lambda phage clones carrying the entire gene and by application of the long and accurate (LA)-PCR method to amplify regions encompassing the exon-intron boundaries and all of the exons. This gene spans about 11kb of genomic DNA and consists of 5 exons and 4 introns. A similarity in the exon-intron organization was found between the genes of mouse HAS1 and Xenopus laevis DG42 which was recently identified as Xenopus hyaluronan synthase. The transcription initiation site was determined by rapid amplification of the cDNA ends (5'-RACE). Position +1 is located 55 nucleotides upstream of the ATG initiation codon. The promoter region of the HAS1 gene has no typical TATA box, but contains a CCAAT box located 190 nucleotides upstream of the transcription initiation site. Further analysis of 1.4 kb of the 5' flanking region revealed several potential binding motifs for transcription factors. This information about the gene structure may be useful for further studies on the promoter activity.
Animals↗
NMDA- and MK801-induced changes in dopamine release are attenuated in kainic acid-lesioned nucleus accumbens of conscious rats: an in vivo microdialysis study.
Local application of N-methyl-d-aspartate (NMDA) and a NMDA receptor antagonist, MK801 through the dialysis membrane into the nucleus accumbens (NAC) caused a significant decrease and increase in extracellular dopamine (DA) in the NAC of conscious rats, respectively. These neurochemical changes were significantly smaller in the kainic acid (KA)-lesioned NAC than in the intact NAC. These findings show that locally applied NMDA and MK801 into the NAC modulate DA release mainly through indirect mechanism involving putative GABA neuron of the NAC.
Animals↗
MKBP, a novel member of the small heat shock protein family, binds and activates the myotonic dystrophy protein kinase.
Muscle cells are frequently subjected to severe conditions caused by heat, oxidative, and mechanical stresses. The small heat shock proteins (sHSPs) such as alphaB-crystallin and HSP27, which are highly expressed in muscle cells, have been suggested to play roles in maintaining myofibrillar integrity against such stresses. Here, we identified a novel member of the sHSP family that associates specifically with myotonic dystrophy protein kinase (DMPK). This DMPK-binding protein, MKBP, shows a unique nature compared with other known sHSPs: (a) In muscle cytosol, MKBP exists as an oligomeric complex separate from the complex formed by alphaB-crystallin and HSP27. (b) The expression of MKBP is not induced by heat shock, although it shows the characteristic early response of redistribution to the insoluble fraction like other sHSPs. Immunohistochemical analysis of skeletal muscle cells shows that MKBP localizes to the cross sections of individual myofibrils at the Z-membrane as well as the neuromuscular junction, where DMPK has been suggested to be concentrated. In vitro, MKBP enhances the kinase activity of DMPK and protects it from heat-induced inactivation. These results suggest that MKBP constitutes a novel stress-responsive system independent of other known sHSPs in muscle cells and that DMPK may be involved in this system by being activated by MKBP. Importantly, since the amount of MKBP protein, but not that of other sHSP family member proteins, is selectively upregulated in skeletal muscle from DM patients, an interaction between DMPK and MKBP may be involved in the pathogenesis of DM.
Amino Acid Sequence↗
Maternal anticipation in Machado-Joseph disease (MJD): some maternal factors independent of the number of CAG repeat units may play a role in genetic anticipation in a Japanese MJD family.
We studied the relationship between the number of CAG repeat units in the MJD1 gene and clinical features of Machado-Joseph disease (MJD) in eight patients from two generations of a Japanese MJD family. Because of lack of characteristic clinical signs of MJD such as dystonia, bulging eyes or facial myokymia, clinical diagnosis of MJD in this family was difficult to make prior to molecular testing for the CAG repeat expansion in the MJD1 gene. All the patients exhibited maternal transmission of MJD, and the intergenerational change in the number of CAG repeat units in the MJD1 gene was very small (+0.5+/-0.3, mean+/-S.E.M., n=4) in spite of marked genetic anticipation (-17.0 years/generation). In the present family, the degree of anticipation per repeat unit in maternal transmissions was much larger than that in maternal transmissions in the other six MJD families. This indicates that some maternal factors other than the increase of the number of CAG repeat units, which is known to be the basis of anticipation, may play a role in genetic anticipation in this MJD family.
Adult↗
Identification of a human homolog of the Drosophila neuralized gene within the 10q25.1 malignant astrocytoma deletion region.
The loss of chromosome 10 is the most frequent genetic alteration found in malignant astrocytomas. In particular, the long arm of chromosome 10 was previously reported to have two or more common deletion regions where tumor suppressor genes may be located. In this study, we performed deletion mapping of 44 malignant astrocytomas using 12 microsatellite markers on chromosome 10q and demonstrated that the minimal common region of loss of heterozygosity (LOH) was present between D10S192 and D10S566 localized at 10q25.1. Subsequently, we have identified a novel gene, termed h-neu, within the region frequently deleted and found that h-neu encodes a protein with strong homology to the Drosophila neuralized (D-neu) protein. Northern blot and RT-PCR analyses revealed that h-neu mRNA was expressed at very low levels in human malignant astrocytoma tissues and the majority of glioma cell lines examined, while normal brains expressed h-neu transcript. Furthermore, DNA sequencing analysis of the h-neu transcript revealed one of the glioma cell lines, U251MG, had a single nucleotide substitution which resulted in an amino acid change from glycine (GGC) to serine (AGC) at codon 253. The D-neu gene is known to serve a critical function in neurogenesis in Drosophila, and loss-of-function mutations produce hyperplasia of primitive neuronal cells. These observations led us to hypothesize that h-neu gene plays a role in determination of cell fate in the human central nervous system and may act as a tumor suppressor whose inactivation could be associated with malignant progression of astrocytic tumors.
Amino Acid Sequence↗
Solution structure of the novel antitumor drug UCH9 complexed with d(TTGGCCAA)2 as determined by NMR.
Aureolic acid group compounds, such as chromomycin A3(CHM) and mithramycin (MIT), are known as antitumor drugs. Recently we isolated a novel aureolic acid group antitumor drug, UCH9, from Streptomyces sp. The chemical structure of UCH9 is unique in that mono- (A ring) and tetrasaccharide (B-E rings) segments and a longer hydrophobic sidechain are attached to the chromophore, while di- and trisaccharide segments and a methyl group are attached to it in the cases of CHM and MIT. It has been shown by two-dimensional agarose gel electrophoresis that the three drugs cause DNA unwinding, UCH9 causing less than the others. A photo-CIDNP experiment has revealed that UCH9 binds to the minor groove of DNA. The structure of the UCH9-d(TTGGCCAA)2 complex has been determined by 1H NMR and simulated annealing calculations. The obtained structure indicates that UCH9 binds as a dimer to the minor groove of d(TTGGCCAA)2, like CHM and MIT, but that the structural change in DNA induced on binding of UCH9 is moderate in comparison with those on binding of the other two drugs. It turns out that the dimer structure of UCH9, stabilized presumably through a hydrophobic interaction involving the A, D and E rings and the hydrophobic sidechain is different from that of CHM and thus DNA can interact with UCH9 in the minor groove with a moderate structural change.
Animals↗
A nitric oxide donor NOC 7 suppresses renal responses induced by norepinephrine and angiotensin II in the NO-depleted denevated rabbit kidney.
Intrarenal arterial infusion of norepinephrine (30 ng/kg per min) or of angiotensin II (4 ng/kg per min) reduced the glomerular filtration rate and urinary Na+ excretion in denervated kidneys of anesthetized rabbits pretreated intrarenally with a nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine methyl ester (50 microg/kg per min). Angiotensin II but not norepinephrine reduced fractional Na+ excretion. Intrarenal administration of a spontaneous NO donor 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene (NOC 7, 30 ng/kg per min) in L-NAME pretreated kidneys did not affect basal values, but attenuated the reduction in urinary Na+ excretion induced by these agonists without affecting the angiotensin II-induced reduction in glomerular filtration rate. The results suggest that NOC 7 can suppress the norepinephrine-induced hypofiltration and the angiotensin II-evoked tubular reabsorption and thereby attenuates the agonist-induced antinatriuresis in the denervated and endogenous NO-depleted rabbit kidney.
Angiotensin II↗
Possible role of cAMP, cGMP and [Ca2+]i during NANC relaxation in the cat airway smooth muscle.
To investigate the possible role of cyclic nucleotides and [Ca2+]i in non-adrenergic non-cholinergic (NANC) relaxations evoked by electrical field stimulation (EFS) in the cat airway, we studied the effects of specific phosphodiesterase (PDE) type IV or V inhibitors on the biphasic-NANC relaxations, the correlation between NANC relaxation and changes in intracellular levels of cAMP and cGMP ([cAMP]i and [cGMP]i), and measured changes in [Ca2+]i during the NANC relaxation. EFS (repetitive stimuli at 20 Hz, 1 or 4 ms pulse duration, 50 V) applied to the bronchial smooth muscle during contraction induced by 5-HT (10(-5) M) in the presence of atropine (10(-6) M) and guanethidine (10(-6) M) elicited biphasic NANC relaxations. Zaprinast (> 3 x 10(-7) M), a specific PDE type V inhibitor, preferentially enhanced the amplitude of the first component of the NANC relaxations. However, rolipram (> 3 x 10(-7) M) enhanced both the first and second component of the NANC relaxation to a similar extent. In the trachea, EFS evoked monophasic NANC relaxation accompanied by a concomitant accumulation of [cAMP]i and [cGMP]i. Pretreatment with rolipram (3 x 10(-6) M) enhanced the accumulation of [cAMP]i and amplitude of NANC relaxation evoked by EFS. However, zaprinast did not affect the amplitude of NANC relaxation although it significantly increased the levels of [cGMP]i. Nomega-Nitro-L-arginine methylester (L-NAME; 10(-5) M) completely suppressed the accumulation of [cGMP]i but only partly suppressed the NANC relaxation evoked by EFS. In contrast, EFS significantly enhanced [cAMP]i in the presence of L-NAME. During NANC relaxation, time-dependent decrease in [Ca2+]i occurred, which was partly suppressed by L-NAME. These results indicate that NANC relaxation is associated with concomitant accumulation in both [cAMP]i and [cGMP]i, and decrease in [Ca2+]i. However, the timing of the action of [cGMP]i and [cAMP]i in NANC relaxations differs in the central and peripheral airway.
Animals↗
ATP synthesis by F0F1-ATP synthase independent of noncatalytic nucleotide binding sites and insensitive to azide inhibition.
ATP hydrolyzing activity of a mutant alpha3beta3gamma subcomplex of F0F1-ATP synthase (DeltaNC) from the thermophilic Bacillus PS3, which lacked noncatalytic nucleotide binding sites, was inactivated completely soon after starting the reaction (Matsui, T., Muneyuki, E. , Honda, M., Allison, W. S., Dou, C., and Yoshida, M. (1997) J. Biol. Chem. 272, 8215-8221). This inactivation is caused by rapid accumulation of the "MgADP inhibited form" which, in the case of wild-type enzyme, would be relieved by ATP binding to noncatalytic sites. We reconstituted F0F1-ATP synthase into liposomes together with bacteriorhodopsin and measured illumination-driven ATP synthesis. Remarkably, DeltaNC F0F1-ATP synthase catalyzed continuous turnover of ATP synthesis while it could not promote ATP-driven proton translocation. ATP synthesis by DeltaNC F0F1-ATP synthase, as well as wild-type enzyme, proceeded even in the presence of azide, an inhibitor of ATP hydrolysis that stabilizes the MgADP inhibited form. The time course of ATP synthesis by DeltaNC F0F1-ATP synthase was linear, and gradual acceleration to the maximal rate, which was observed for the wild-type enzyme, was not seen. Thus, ATP synthesis can proceed without nucleotide binding to noncatalytic sites even though the rate is sub-maximal. These results indicate that the MgADP inhibited form is not produced in ATP synthesis reaction, and in this regard, ATP synthesis may not be a simple reversal of ATP hydrolysis.
Adenosine Triphosphate↗
Thermal control of drug release by a responsive ion track membrane observed by radio tracer flow dialysis.
The combination of a responsive hydrogel with a rigid porous supporting structure yield a membrane with high mechanical strength and high on-off-permeability ratio. A membrane consisting of an ion track filter with a thermally responsive lining was prepared by penetrating a 19 micron thick foil of poly(ethylene terephthalate) (PET) with swift heavy ions at a fluence of 5 x 10(5) ions/cm2, followed by etching of the ion tracks to generate an ion track filter with 2.9 micron pore diameter, onto which a thin layer of poly(N-isopropylacrylamide) (NIPAAm) hydrogel was grafted. It was revealed that the mass flow of various molecules (water, chloride-, choline+, insulin, and albumin) through the membrane could be thermally controlled. The on-off-permeability ratio ranged between 3 and 10 increasing with molecular weight. Over a storage time of 5 months the permeabilities varied up to a factor of 2.6, while the on-off-permeability ratio and temperature sensitivity remained practically constant.
Drug Delivery Systems↗
Multiple myeloma associated with serum amino acid disturbance and high output cardiac failure.
We experienced a plasma cell leukemia (PCL) patient complicated with high output cardiac failure (HOCF), proved as his elevated cardiac index and pulmonary artery wedge pressure and decreased systemic vascular resistance index in a hemodynamic study. We found no possible causes of HOCF. Interestingly, HOCF was improved as PCL responded to intensive chemotherapy. On the other hand, he showed consciousness disturbance, and had frequent attacks of generalized seizure. His electroencephalogram showed slow waves, and a spike and wave complex. Hyperammonemia and abnormal amino acid distribution were also found. This abnormal serum amino acid distribution, especially elevated glycine level, was different from that seen in chronic liver failure, and he had no hepatic disease. After intensive chemotherapy, the serum ammonia level and glycine level decreased. In this patient, PCL seemed to be responsible for HOCF, hyperammonemia, and abnormal amino acid distribution. We experienced two more cases of multiple myeloma (MM) with HOCF, hyperammonemia, abnormal serum amino acid distribution, and consciousness disturbance of unknown origin. Those two cases showed slow waves in the electroencephalogram. Improvement was seen in their HOCF, hyperammonemia, and abnormal amino acid levels after chemotherapy. The possibility of MM as a cause of HOCF is discussed.
Adult↗
From dystrophinopathy to sarcoglycanopathy: evolution of a concept of muscular dystrophy.
Duchenne and Becker muscular dystrophies are collectively termed dystrophinopathy. Dystrophinopathy and severe childhood autosomal recessive muscular dystrophy (SCARMD) are clinically very similar and had not been distinguished in the early 20th century. SCARMD was first classified separately from dystrophinopathy due to differences in the mode of inheritance. Studies performed several years ago clarified some immunohistochemical and genetic characteristics of SCARMD, but many remained to be clarified. In 1994, the sarcoglycan complex was discovered among dystrophin-associated proteins. Subsequently, on the basis of our immunohistochemical findings which indicated that all components of the sarcoglycan complex are absent in SCARMD muscles, and the previous genetic findings, we proposed that a mutation of any one of the sarcoglycan genes leads to SCARMD. This hypothesis explained and predicted various characteristics of SCARMD at the molecular level, most of which have been verified by subsequent discoveries in our own as well as various other laboratories. SCARMD is now called sarcoglycanopathy, which is caused by a defect of any one of four different sarcoglycan genes, and thus far mutations in sarcoglycan genes have been documented in the SCARMD patients. In this review, the evolution of the concept of sarcoglycanopathy separate from that of dystrophinopathy is explained by comparing studies on these diseases.
Animals↗
Ultrastructure of the foregut and associated glands in the lung fluke, Paragonimus miyazakii (Digenea: Troglotrematidae), with particular reference to their functional roles.
The foregut and associated glands of a digenetic trematode, Paragonimus miyazakii, were examined in the forebody by transmission and scanning electron microscopy as well as by light microscopy, and their functional roles were discussed. The foregut is lined with a general tegument without spines and sensory receptors throughout its length, although it consists of the mouth, pharynx, and esophagus. This foregut tegument is regionally and intraregionally modified in appearance, suggesting the performance of auxiliary functions in digestion. This appearance is characterized by long, frequent cytoplasmic extensions of the apical tegument around the middle portion of the mouth and the anterior esophagus. Electron-dense granules and multimembranous and multilamellar bodies are developed in the tegument to various degrees, and elaborately in the apical layer of the prepharynx. A single type of unicellular gland is embedded in the antero-middle part of the worm in small groups. The gland cells synthesize clear secretory granules as a chief product, each granule with a pleomorphic, dense, core-like inclusion. Mature granules are elliptical in shape, approximately 500 nm in diameter, and are subsequently discharged into the prepharyngeal foregut lumen after passing through the elongated cytoplasm of the gland cell. In the prepharynx and pharynx, host blood cells are apparently processed for digestion. In the wide lumen of the esophagus, foodstuff could undergo sufficient digestion prior to absorption by the cecal epithelium.
Animal Structures↗
Natural killer cell activity reduced by microwave exposure during pregnancy is mediated by opioid systems.
We have previously demonstrated immunosuppression including reduced splenic natural killer cell activity (NKCA) in pregnant rats exposed to microwaves produced mainly by their thermal action. To examine the involvement of opioid systems in reduced NKCA in pregnant rats exposed to microwaves at a relatively low level (2 mW/cm2 incident power density at 2450 MHz for 90 min), we assayed beta-endorphin (betaEP) in blood, pituitary lobes, and placenta as well as splenic NKCA in virgin and/or pregnant rats. Although microwaves elevated colonic temperatures by 0.8 degreesC for virgin and 0.9 degreesC for pregnant rats, and betaEP in blood and anterior pituitary lobes (AP) significantly, it did not change blood corticosterone as an index of hypothalamic-pituitary adrenal axis. There were significant interactions between pregnancy and microwave exposure on splenic NKCA, betaEP in both blood and AP, and blood progesterone. Intra-peritoneal administration of opioid receptor antagonist naloxone prior to microwave exposure increased NKCA, blood, and placental betaEP in pregnant rats. Alterations in splenic NKCA, betaEP and progesterone in pregnant rats exposed to microwaves may be due to both thermal and nonthermal actions. These results suggest that NKCA reduced by microwaves during pregnancy is mediated by the pituitary opioid system.
Animals↗