Biomedical subjects

M Kishi

Publications and source records attributed to M Kishi.

At least 37 records · Page 2Linked to original sources

PubMed2000

Spectroscopic and electrochemical studies on structural change of plastocyanin and its tyrosine 83 mutants induced by interaction with lysine peptides.

Interactions of wild-type and Tyr83 mutant (Y83F, Y83S, Y83L, and Y83H) plastocyanins (PCs) with lysine peptides as models for the PC interacting site of cytochrome f have been studied by absorption, resonance Raman, and electron paramagnetic resonance (EPR) spectroscopies and electrochemical measurements. The spectral and electrochemical properties of PCs corresponded well with each other; species having a longer wavelength maximum for the S(Cys) pi --> Cu 3d(x)()()2(-)(y)()()2 charge transfer (CT) band observed around 600 nm and a stronger intensity for the 460-nm absorption band exhibited stronger intensities for the positive Met --> Cu 3d(x)()()2(-)(y)()()2 and negative His pi(1) --> Cu 3d(x)()()2(-)(y)()()2 circular dichroism (CD) bands at about 420 and 470 nm, respectively, a lower average nu(Cu)(-)(S) frequency, a smaller |A( parallel)| EPR parameter, and a higher redox potential, properties all related to a weaker Cu-S(Cys) bond and a more tetrahedral planar geometry for the Cu site. Similarly, on oligolysine binding to wild-type and several Tyr83 mutant PCs, a longer absorption maximum for the 600-nm CT band, a stronger intensity for the 460-nm absorption band, stronger 420-nm positive and 470-nm negative CD bands, and a lower average nu(Cu)(-)(S) frequency were observed, suggesting that PC assumes a slight more tetrahedral geometry on binding of oligolysine. Since changes were observed for both wild-type and Tyr83 mutant PCs, the structural change due to binding of oligolysine to PC may not be transmitted through the path of Tyr83-Cys84-copper by a cation-pi interaction which is proposed for electron transfer.

Amino Acid Substitution↗

PubMed2000

Replication ability in vitro and in vivo of equine infectious anemia virus avirulent Japanese strain.

An attenuated equine infectious anemia virus (EIAV), V26, was previously prepared by 50 passages of the Japanese virulent strain V70 in primary horse macrophage culture. The horses inoculated with this V26 virus were shown to raise neutralizing antibodies against V70 without any viremia. Here, we investigated the in vitro and in vivo replication ability of V26. Comparison of the long-terminal repeat (LTR) sequences between V26 and V70 revealed a large insertion within the LTR U3 hypervariable region of V26. V26 with the mutation in the LTR showed much higher promoter activity in vitro than V70. This is consistent with the much higher replication rate of V26 in horse primary macrophage cultures compared with V70. In sharp contrast, we failed to identify the V26-specific LTR sequence by PCR, at least in sequential samples of plasma or peripheral blood mononuclear cells derived from three horses until day 62 after V26 inoculation. In contrast, antibody responses to EIAV were observed in all horses. The results suggest that the replication ability of V26 in vivo is extremely low. When one of the horses was subsequently challenged with cell-associated V70, it was found that the horse became PCR positive for EIAV. There was no LTR mutation in EIAV genome in samples periodically prepared from the V70-challenged horse. Thus it was suggested that the LTR mutation in EIAV, which occurs during serial passage in vitro, affects EIAV replication in vitro and in vivo.

Animals↗

PubMed2000

Involvement of cyclic AMP - PKA pathway in VIP-induced, charybdotoxin-sensitive relaxation of longitudinal muscle of the distal colon of Wistar-ST rats.

The intracellular mechanism of vasoactive intestinal peptide (VIP)-induced, charybdotoxin (ChTx)-sensitive relaxation of longitudinal muscle of the distal colon of Wistar-ST rats was studied. A single pulse or 100 pulses at 10 Hz of electrical field stimulation (EFS) induced rapid transient relaxation or that with a subsequent contraction of the longitudinal muscle in the presence of atropine and guanethidine, respectively. Rp-8 bromo cAMPS, an inhibitor of cyclic AMP dependent protein kinase (PKA), at 30 microM inhibited the relaxations induced by EFS with a single or 100 pulses maximally by about 80 or 60%, respectively. It also inhibited VIP (300 nM)-induced relaxation by 82%. VIP (100 nM - 1 microM) increased the cyclic AMP content of longitudinal muscle myenteric plexus preparations obtained from the distal colon. ChTx at 100 nM almost completely inhibited 8 bromo cyclic AMP-induced relaxation of the distal segments. EFS with two or three pulses at 10 Hz induced inhibitory junction potentials consisting of two phases, rapid and subsequent slow hyperpolarization in the membrane potential of longitudinal smooth muscle cells. Rp-cAMPS, another inhibitor of PKA, inhibited the delayed slow hyperpolarization. It also inhibited the exogenously added VIP-induced hyperpolarization of the cell membrane. Thus, the present study suggests that activation of PKA via activation of VIP receptors is associated with activation of ChTx-sensitive K(+) channels in relaxation of longitudinal muscle of the distal colon of Wistar-ST rats. British Journal of Pharmacology (2000) 129, 140 - 146

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2000

Characteristics of infection and leukocyte count in severely head-injured patients treated with mild hypothermia.

OBJECTIVE: This study was designed to characterize the infectious complications and kinetics of leukocyte count in severely head-injured patients treated with mild hypothermia. PATIENTS AND METHODS: We retrospectively analyzed the incidence and severity of infectious complications as well as daily changes in leukocyte count in 41 severely head-injured patients treated with mild hypothermia (group H). They were retrospectively compared with 25 severely head-injured patients treated with high-dose barbiturates (group B) and to 25 other severely head-injured patients treated with no barbiturates (group N). RESULTS: Initial intracranial pressure was significantly higher in group H than in the other groups. No significant differences existed in the incidence of pneumonia or meningitis among the three groups, whereas the incidence of bacteremia was significantly higher in group H than in the other two groups. Pneumonia was significantly more severe in group H than in the other groups. In six patients of group H, pneumonia spread fulminantly to become life threatening. Daily changes in total leukocyte count showed the same pattern, consisting of a peak, a nadir, and a second peak in all groups. Total leukocyte count was, however, significantly lower during the first 2 weeks in group H than in the other two groups. Lymphocyte and neutrophil counts were also lower in group H. CONCLUSION: Infectious complications were more severe and leukocyte counts were lower in patients treated with mild hypothermia, who also had the highest initial intracranial pressures, than in patients treated with conventional therapies. Measures against increased susceptibility to infection and leukocyte suppression should be explored.

Abbreviated Injury Scale↗

PubMed2000

Characterization of the P protein-binding domain on the 10-kilodalton protein of Borna disease virus.

The Borna disease virus (BDV) is the prototype member of the Bornaviridae, and it replicates in the cell nucleus. The BDV p24P and p40N proteins carry nuclear localization signals (NLS) and are found in the nuclei of infected cells. The BDV p10 protein does not have an NLS, but it binds with P and/or N and is translocated to the nucleus. Hence, p10 may play a role in the replication of BDV in the cell nucleus. Here, we show that the P-binding domain is located in the N terminus of p10 and that S(3) and L(16) are important for the interaction.

Amino Acid Sequence↗

PubMed2000

The C-terminal tail of the rat lutropin/choriogonadotropin (CG) receptor independently modulates human (h)CG-induced internalization of the cell surface receptor and the lysosomal targeting of the internalized hCG-receptor complex.

The analysis of 21 progressive truncations of the C-terminal tail of the rat LH/CG receptor (rLHR) revealed the presence of a region delineated by residues 628-649 that, when removed, enhanced the degradation of the internalized human (h)CG. The analysis of these truncations also revealed the presence of a region delineated by residues 624-631 that, when removed, enhanced the rate of internalization of hCG. Since there is little overlap between these two regions, we conclude that the structural features of the rLHR that mediate internalization and degradation of the internalized hormone are different. Detailed analyses of cells expressing a truncation at Y637 (designated rLHR-t637) showed that the enhanced degradation of hCG observed in the these cells is due to an increase in the rate of transfer of the internalized hCG-rLHR complex from the endosomes to the lysosomes rather than to the enhanced dissociation of the hCG-rLHR complex in the lysosomes.

Amino Acid Sequence↗

PubMed2000

Requirement of Sox2-mediated signaling for differentiation of early Xenopus neuroectoderm.

From early stages of development, Sox2-class transcription factors (Sox1, Sox2 and Sox3) are expressed in neural tissues and sensory epithelia. In this report, we show that Sox2 function is required for neural differentiation of early Xenopus ectoderm. Microinjection of dominant-negative forms of Sox2 (dnSox2) mRNA inhibits neural differentiation of animal caps caused by attenuation of BMP signals. Expression of dnSox2 in developing embryos suppresses expression of N-CAM and regional neural markers. We have analyzed temporal requirement of Sox2-mediated signaling by using an inducible dnSox2 construct fused to the ligand-binding domain of the glucocorticoid receptor. Attenuation of Sox2 function both from the late blastula stage and from the late gastrula stage onwards causes an inhibition of neural differentiation in animal caps and in whole embryos. Additionally, dnSox2-injected cells that fail to differentiate into neural tissues are not able to adopt epidermal cell fate. These data suggest that Sox2-class genes are essential for early neuroectoderm cells to consolidate their neural identity during secondary steps of neural differentiation.

Animals↗

PubMed2000

Hepatic veno-occlusive lesions and other histopathological changes of the liver in severe alcoholic hepatitis--a comparative clinicohistopathological study of autopsy cases.

BACKGROUND: The clinicopathological features of veno-occlusive lesions (VOL) in the liver were studied in 18 autopsy cases of severe alcoholic hepatitis (sALH). All the cases were heavy drinkers and died of liver failure or variceal rupture. METHODS: We performed histological evaluation by examining stained sections of liver blocks from each case. The severity of VOL was compared with the clinical findings and histopathological changes of alcoholic liver diseases (ALD). RESULTS: Clinically, as the severity of VOL increased, the amount of ascites observed during autopsy increased significantly (p = 0.001) and the time from hospitalization to death was significantly longer (p < 0.05). The peripheral leukocyte count tended to increase and the serum bilirubin level increased significantly (p < 0.05) with increased VOL severity, after we excluded one case that was complicated by acute respiratory distress syndrome and bacterial endocarditis. Histopathologically, the appearance of Mallory bodies increased significantly as VOL became more severe (p < 0.05), but the VOL severity did not correlate with sinusoidal neutrophil infiltration. Fatty degeneration tended to be milder as VOL increased in severity although the difference was not significant, whereas bile retention tended to be more marked. CONCLUSIONS: We conclude that investigation of VOL is clinicopathologically important when assessing the pathophysiology and severity of sALH.

Adult↗

PubMed2000

[A case report of Bickerstaff's brainstem encephalitis with positive anti GQ 1 b, GT 1 a, GM 1 ganglioside antibodies].

Patient was an 18-year-old female student. After she had symptoms of common cold for 3 days, she developed somnolence, diplopia, dysarthria, urinary disturbance and ataxia. On admission neurological examination revealed coma with mydriasis, ophthalmoplegia, ptosis and weakness of the upper limbs. Light reflex, corneal reflex and oculocephalic test were all negative. Deep tendon reflexes were brisk and extensor toe signs were positive bilaterally. She did not have nuchal rigidity. Laboratory test revealed normal cerebrospinal fluid with negative myelin basic protein. Brain MRI, brainstem evoked potentials presented no abnormality. EMG revealed normal conduction velocity and no conduction block. EEG had diffuse theta and delta slowing. Culture of the stool represented no Campylobacter jejuni. At the fifth day of admission consciousness level improved, and other neurological findings disappeared in about 6 weeks. She had anti GQ 1 b, GT 1 a(IgG, IgM) and anti GM 1(IgM) antibodies in the serum. We made a diagnosis of Bickerstaff's brainstem encephalitis from these neurological symptoms and clinical course. The main lesion was present in the brainstem from midbrain to medulla oblongata in the midline. High titer of anti GT 1a antibody may be related to the ophthalmoplegia as noted in Miller Fisher syndrome. As a result of EMG and stool culture, it denied the complication of Guillain-Barré syndrome. We had no proof of the reason of the presentation of anti GM 1 antibody.

Adolescent↗

PubMed1999

Structure and distribution of rat menin mRNA.

Menin is a protein product of a tumor suppressor gene MEN1, mutations of which are responsible for multiple endocrine neoplasia type 1, an autosomal dominant familial cancer syndrome. We isolated rat menin cDNA clones from a fetal rat brain cDNA library. We also determined the nucleotide sequence of the protein coding region of mouse menin cDNA, which was partly registered in the expressed sequence tag (EST) database. Deduced amino acid sequences of rat and mouse menin are highly homologous to human menin. All of the previously reported disease-associated missense mutations and single amino acid deletions were observed at the residues that are conserved among these three species. Rat MEN1 transcripts were detected not only in the endocrine tissues but also in the tissues of the nervous, digestive, reproductive and immune systems. The MEN1 transcripts were abundantly expressed in the developing rat brain on day 14-18 of gestation. Immunoblotting and immunocytochemical analysis of the COS-7 cells transfected with a rat menin-expression vector revealed that the translated product has a molecular mass of approximately 70 kDa, and is localized mainly in the nucleus. These findings are consistent with those reported on human menin.

Amino Acid Sequence↗

PubMed1999

A novel splicing mutation (894-9 G --> A) of the MEN1 gene responsible for multiple endocrine neoplasia type 1.

Germline MEN1 gene mutations are responsible for multiple endocrine neoplasia type 1 (MEN1), a dominantly inherited cancer syndrome. We identified a MEN1 germline mutation 894-9 G --> A in three MEN1 patients from two unrelated families. This mutation was not present in any of the 100 blood samples from normal volunteers. The wild type MEN1 sequence was lost in the patient's pancreatic tumor. Abnormal mRNA was identified in the tumor, which retained an intronic sequence indicating aberrant mRNA splicing at a newly created splicing acceptor site. These findings indicate that this nucleotide substitution is, though previously reported to be a polymorphism, a causative splicing mutation.

Adult↗

PubMed1999

Nuclear localization of the protein from the open reading frame x1 of the Borna disease virus was through interactions with the viral nucleoprotein.

Previous studies have predicted the presence of a small open reading frame (ORFx1) located between ORF-1 and ORF-2 of the Borna disease viral (BDV) genome. The ORFx1 is expressed as a p10 protein that is localized in the nucleus and cytoplasm of BDV-infected cells. In this study, we cloned the nucleotide sequence of ORFx1 into expression vectors and showed that it is expressed as p10. An anti-p10 serum gave nuclear and cytoplasmic staining of cells persistently infected with BDV. Immunoprecipitation of p10 from BDV-infected cells coprecipitated the p40 nucleoprotein N and the 24-kDa viral phosphoprotein P. Transient transfection of noninfected cells showed that p10 and p40 can be coprecipitated and revealed that p10 localized in the cytoplasm was imported into the nucleus in the presence of the BDV p40 N. In vitro protein-protein interaction studies on solid phase showed the direct interaction of the p10 with the BDV N protein. The subcellular distribution of p10 and its interaction with p40 suggest that this protein may play a role in the nuclear replication and/or transcription of BDV.

Amino Acid Sequence↗

PubMed1999

Lactation-dependent expression of an mRNA splice variant with an exon for a multiply O-glycosylated domain of mouse milk fat globule glycoprotein MFG-E8.

Expression of mRNA encoding MFG-E8, a milk fat-associated glycoprotein was investigated in mouse mammary gland. Two forms of mRNA, long and short variants, were shown to be expressed in the mammary tissue by RT-PCR analysis. Sequence analyses of these two variants and an isolated MFG-E8 gene segment indicated that the long and short mRNA variants resulted from an alternative splicing of a single pre-mRNA through in-flame inclusion and skipping of one exon, which encodes a proline/threonine (Pro/Thr)-rich domain. The long variant was expressed predominantly in mammary gland and the expression level was remarkably increased at late gestation and kept high during lactation. On the contrary, the short variant was detected ubiquitously in various tissues and its expression in the mammary gland was rather decreased in a lactation dependent manner. Expression of the long variant was also detected in a mouse mammary epithelial cell line, COMMA-1D, and enhanced by incubation with lactogenic hormones. Glycosylation inhibition analyses using tunicamycin and alpha-benzyl-GalNAc were conducted with COS7 cells transfected with plasmids expressing each mRNA variant, demonstrating that a fully glycosylated product of the long mRNA variant was not only N-glycosylated but also multiply O-glycosylated, whereas a product of the short one had only N-glycan(s). These results suggest that the alternative splicing plays a critical role for the mammary-specific and lactation-dependent expression of the MFG-E8 isoform and that the multiply O-glycosylated Pro/Thr-rich domain of this isoform is functionally important for formation of milk fat globules in mammary epithelial cells.

Alternative Splicing↗

PubMed1999

Tyrosine kinase involvement in apamin-sensitive inhibitory responses of rat distal colon.

1. It has been suggested that pituitary adenylate cyclase activating peptide (PACAP) may be involved in the non-adrenergic, non-cholinergic (NANC) inhibitory response of longitudinal muscle of rat distal colon. In this study, we have investigated the intracellular mechanism of PACAP-induced relaxation in this muscle. 2. PACAP induced an apamin-sensitive relaxation of the longitudinal muscle. The tyrosine kinase inhibitors genistein at 10 microM and tyrphostin 25 at 30 microM, but not the cyclic AMP-dependent protein kinase inhibitor Rp-8-bromoadenosine-3',5'-cyclic monophosphorothioate at 30 microM significantly inhibited the PACAP-induced relaxation to 60% and 25% of control values, respectively. PACAP did not increase the cyclic AMP content of the muscle. 3. Tyrphostin 25 at 10 microM significantly inhibited the relaxation of longitudinal muscle induced by electrical field stimulation (EFS), to 50% of control values. Apamin at 1 microM, an antagonist of small conductance Ca2+-activated K+ channels, also inhibited the relaxation, to 42 % of control values. The inhibitory effects of tyrphostin 25 and apamin were not additive (44 % of control values). 4. PACAP induced an apamin-sensitive, slow hyperpolarization of the cell membrane of the muscle. Tyrphostin 25 at 3 microM inhibited this PACAP-induced hyperpolarization. Tyrphostin 25 at 10 microM and genistein at 10 microM inhibited the apamin-sensitive inhibitory junction potentials induced by a single pulse of EFS. 5. The PACAP-induced relaxation of longitudinal muscle occurred with a concomitant decrease in intracellular Ca2+ levels ([Ca2+]i). Tyrphostin 25 at 10 microM and apamin at 1 microM abolished these PACAP-induced responses. 6. From these findings it is suggested that the activation of tyrosine kinase is involved in PACAP-induced relaxation of longitudinal muscle from rat distal colon, 'upstream of' the activation of apamin-sensitive K+ channels.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1999

Ultrasound-guided follicle aspiration: the collection of bovine cumulus-oocyte complexes from ovaries of slaughtered or live cows.

To increase the collection efficiency of bovine cumulus-oocyte-complexes (COCs) by transvaginal aspiration, the effects of aspiration pressure and needle diameter on bovine follicular oocyte collection were assessed. Oocytes were aspirated from ovaries of slaughtered cows using 2 different diameter needles (18- or 21-gauge) with 4 different aspiration pressures (40, 80, 120 or 160 mmHg) and of live cows using 18-gauge needles with 40 or 80 mmHg, or using 21-gauge needles with 80 or 120 mmHg. The recovered oocytes were divided into 4 categories according to the surrounding cumulus cells and quality of oocytes: 1) 4 or more layers, 2) between 1 and 3 layers, 3) completely or partially denuded and 4) all others, including expanded cumulus cells and degenerated oocytes. The highest oocyte recovery rates from Categories 1 and 2 were obtained using 18-gauge needles with 40 mmHg pressure and 21-gauge needles with 120 mmHg pressure, respectively, from the ovaries of slaughtered cows. When oocytes were collected from live cows, the highest recovery rates for Categories 1 and 2 were obtained using an 18-gauge needle and 40 mmHg pressure, and 21-gauge needle and 80 mmHg, respectively. In addition, the proportion of oocytes in each category were compared between ovaries from slaughtered and live cows. The proportion of Category 1 oocytes collected from live cows was lower than from slaughtered cows when 18-gauge needles at 80 mmHg (P<0.05). The results show that the combination of aspiration pressure and needle diameter is crucial for COC collection, and they suggest that optimal aspiration conditions for ovaries of slaughtered cows are not necessarily applicable to live cows.

Animals↗

PubMed1999

Morbidity and mortality of hospitalized patients after the 1995 Hanshin-Awaji earthquake.

The objective of this study was to provide an overview of the morbidity and mortality of hospitalized patients during the Hanshin-Awaji earthquake. Medical records of 6,107 patients admitted to 95 hospitals (48 affected hospitals within the disaster area and 47 back-up hospitals in the surrounding area) during the initial 15 days after the earthquake were analyzed retrospectively. Patient census data, diagnoses, dispositions, and prognoses were considered. A total of 2,718 patients with earthquake-related injuries were admitted to the 95 hospitals included in our survey, including 372 patients with crush syndrome and 2,346 with other injuries. There were 3,389 patients admitted with illnesses. Seventy-five percent of the injured were hospitalized during the first 3 days. In contrast, the number of patients with illnesses continued to increase over the entire 15-day period after the earthquake. The mortality rates were 13.4% (50/372), 5.5% (128/2,346), and 10.3% (349/3,389) associated with crush syndrome, other injuries, and illness, respectively. The overall mortality rate was 8.6% (527/6,107 patients). Morbidity as well as mortality rates increased with age in patients with both injuries and illnesses. In the initial 15-day period, there was an unprecedented number of patients suffering from trauma, and they converged upon the affected hospitals. Subsequently an increased incidence of illness was observed. This survey underscores the need for adequate disaster response in such an urban situation.

Adolescent↗

PubMed1999

Multiple sclerosis with extensive lesions left hemiplegia, mental dysfunction and retrobulbar neuritis.

Multiple sclerosis (MS) is usually diagnosed on the basis of the typical clinical course, with remission and exacerbation in multiple parts of the central nervous system (CNS). Recently, magnetic resonance imaging (MRI) has made a large contribution to the diagnosis of patients with MS. But it is difficult to make a definite diagnosis due to clinical variability of the disease and variable MRI findings. We report the case of a 26-year-old woman who developed progressive left hemiplegia, mental dysfunction, and had extensive bilateral cerebral white matter lesions diagnosed by brain MRI. Complete recovery from the left hemiplegia followed the use of corticosteroid, and her brain MRI findings also improved after medication. Early in the clinical course it was difficult to differentiate between multiple sclerosis and granulomatous angiitis of the CNS. After recovery from the first episode of left hemiplegia and mental dysfunction, she developed acute visual disturbance five months after her first admission. Readmission followed and her retrobulbar neuritis was successfully treated by methylpredonisolone pulse therapy. In summary, she experienced two episodes of neurological deficit, had left hemiplegia and mental dysfunction associated with multiple lesions in bilateral cerebral white matter in brain MRI, and the left retrobulbar neuritis with delay of P100 by visual evoked potential study. Due to these two episodes we concluded that she had multiple sclerosis. Though the initial diagnosis was difficult, prompt treatment and close follow-up was important, since multiple sclerosis and granulomatous angiitis of the CNS can both recur.

Adult↗

PubMed1999

Hepatic veno-occlusive lesions in severe alcoholic hepatitis and alcoholic liver cirrhosis: a comparative histopathological study in autopsy cases.

Clinicopathological features of veno-occlusive lesions in hepatic veins were studied in autopsy cases of severe alcoholic hepatitis (15 cases) and alcoholic liver cirrhosis (15 cases). All the cases were heavy drinkers and died of liver failure or variceal rupture. The frequency and degree of veno-occlusive lesions, and the diameter and number of hepatic veins were studied from stained sections of liver blocks from each case. The hepatic veins observed ranged from 60 to 3000 microm in diameter. The veno-occlusive lesions were found in hepatic veins mainly 60 to 1200 microm in diameter. These findings were recognized in the majority of severe alcoholic hepatitis cases and alcoholic liver cirrhosis cases. Furthermore, more severe veno-occlusive lesions were noted in severe alcoholic hepatitis, compared with alcoholic liver cirrhosis. In the cases with obstruction in hepatic veins of >400 microm, a decrease in the number of hepatic veins and zonal necrosis were noted. In addition, some of the veno-occlusive lesions were recognized focally in the same cases. Clinical findings also indicated that ascites increased with the progression of the veno-occlusive lesions. We conclude that investigation of veno-occlusive lesions in severe alcoholic liver disease has clinicopathological significance.

Adult↗