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Biomedical subjects

K Ishii

Publications and source records attributed to K Ishii.

At least 19 recordsLinked to original sources
PubMed1992

Inhibition of passive cutaneous anaphylaxis by synthetic human immunoglobulin E peptide fragments.

In an attempt to determine the regions responsible for type I immediate hypersensitivity, a total of 42 peptide fragments, which cover the CH3-CH4 domains in human immunoglobulin E (IgE), were chemically synthesized. Several peptide fragments located in the amino acid sequences Ala329-Thr357 and Arg419-Ala463, inhibited passive cutaneous anaphylaxis (PCA) in vivo. In order to pinpoint the sites responsible for the inhibition of the PCA reaction, various fragment peptides in these two regions were synthesized. As a result, residues Pro343-Leu348, Pro426-Thr433, and Ser456-Thr461 were suggested to be involved in type I immediate hypersensitivity.

Amino Acid Sequence↗
PubMed1992

Isolation and identification of C-type natriuretic peptide in human monocytic cell line, THP-1.

In a survey for unknown bioactive peptides in mammalian cell lines, we isolated peptides exhibiting a strong relaxant effect on chick rectum from a phorbol ester-supplemented culture medium of the human monocytic cell line, THP-1. The peptide was deduced to be a C-terminal 29-residue peptide derived from a human C-type natriuretic peptide (CNP) precursor. CNP mRNA was also detected in the THP-1 cells, and expression of CNP gene and CNP concentration in the culture medium was found to be highly augmented by the stimulation of phorbol ester. Production of CNP in THP-1 cells suggests that CNP also functions as a local regulator in the blood cell-vascular system, although CNP has previously been recognized as a neuropeptide functioning in the central nervous system.

Amino Acid Sequence↗
PubMed1992

Modulation of transient type K channel cloned from rat heart.

We have cloned a transient type K channel from rat heart (RH10) and coexpressed a metabotropic glutamate receptor (mGluR5) to study the functional modulation of RH10 coupled to the phosphatidylinositol (PI) hydrolysis. Stimulation of mGluR5 suppressed peak amplitude of RH10 current and affected voltage dependence of activation and inactivation of the channel.

Animals↗
PubMed1992

Gene expression of mouse choline acetyltransferase. Alternative splicing and identification of a highly active promoter region.

Seven types of mRNA for choline acetyltransferase that differ in the 5'-noncoding region were identified in the mouse spinal cord by cDNA cloning and polymerase chain reaction. Among these transcripts, the M-type mRNA corresponding to the previously cloned mouse cDNA was most abundant in the spinal cord of mouse. A mouse genomic DNA clone containing the 5'-region of choline acetyltransferase mRNA was isolated and sequenced. Comparison of the sequences between the cDNAs and the genomic DNA revealed that the different mRNA species were transcribed from different promoter regions and produced by differential splicing. Two murine cholinergic cell lines, NS20Y and NG108-15, were shown to express the M-type mRNA almost exclusively, and were therefore used to study transcription of M-type mRNA. Fragments of the 5'-region of choline acetyltransferase gene were ligated with chloramphenicol acetyltransferase reporter gene and introduced into cultured cells. The fragment from -2752 to +46, which contained the M-type exon, a TATA-box like element upstream of the M-type exon, and the downstream intron, induced a significant expression of CAT activity in neuronal but not in non-neuronal cell lines. This result indicates that this region of choline acetyltransferase gene contains elements that regulate neuron-specific expression of choline acetyltransferase activity. However, there was no parallel correlation between reporter gene expression in the transfected cells and intrinsic choline acetyltransferase activity in these neuronal cell lines. Possible mechanisms that would explain this observation are discussed.

Alternative Splicing↗
PubMed1992

[Clinical evaluation of hepatic scintigraphy using 99mTc-GSA].

Functional hepatic imaging was performed using 99mTc-DTPA-galactosyl human serum albumin (99mTc-GSA), a radiolabeled ligand that reacts specifically to the asialoglycoprotein receptor that resides at the plasma membrane of hepatocytes, in 21 patients: five with chronic active hepatitis (CAH), 14 with compensative liver cirrhosis (LC), one with chronic inactive hepatitis and one with acute hepatitis. The former two diseases were mainly investigated. Serial liver images were acquired at the rates of 10 sec/frame for 0-5 min and 2 min/frame for 6-30 min after the injection of 99mTc-GSA, and the images were compared with 99mTc-phytate images in 2 patients with CAH and 11 with LC, and those with portal scintigrams using 123I-iodoamphetamine (IMP) in 3 patients with LC. The images using 99mTc-GSA were in better agreement with hepatic function than those using 99mTc-phytate, and with the findings of portal scintigraphy using 123I-IMP. LHL15 (liver/liver and heart radioactivities at 15 min after the injection of 99mTc-GSA) correlated with the hepaplastin test (r = 0.978 in CAH, and r = 0.544 in LC), indicators of hepatic reserve. These results suggest that liver scintigraphy using 99mTc-GSA might be a useful method for evaluating liver function.

Adult↗
PubMed1992

Inhibitory effect of noradrenaline on acute liver injury induced by carbon tetrachloride in the rat.

The effect of exogenous noradrenaline (NA) on acute liver injury was investigated in rats receiving a single dose of carbon tetrachloride (CCl4). Animals were divided into the following groups: (I) no treatment, used for plasma catecholamine assay; (II) received CCl4 only; (III) treated with CCl4 plus noradrenaline (NA). Plasma levels of catecholamine (CA) were elevated in both groups II and III, particularly in NA: average value at 33 h after the exposure of CCl4 increased to 290-fold of the control in group II and to 513-fold in group III. Subsequently, the levels of NA decreased with time, and were comparatively well-preserved in the rats of group III. Hepatic changes observed in the animals of group II were as follows: destruction with reduced number in rough endoplasmic reticulum; destruction and disappearance of cristae in mitochondria, and numerous fat droplets (shown by electron microscopy); histologically observed marked centrilobular necrosis with steatosis followed by progression with time; and microangiographically demonstrated deranged intrahepatic microvasculature. By contrast, these changes were successfully prevented by NA treatment (group III). Furthermore, histologically observed centrilobular change was restored with time. It was concluded that, in a deranged state, NA takes a form quite dissimilar to ordinary state: Na exerts for hapatoprotective and is highly involved in liver injury.

Animals↗
PubMed1992

Cloning and modulation by endothelin-1 of rat cardiac K channel.

We have cloned a delayed rectifier type K channel from rat heart (RH1). RH1 was identical to the rat brain K channel BK2 and differed from recently cloned rat cardiac K channel RAK by one amino acid residue. Endothelin receptors(ETRs)-mediated modulation of RH1 current (IRH1) was studied using Xenopus oocyte expression system. Activation of two different subtypes of ETRs by endothelin-1 equally suppressed the amplitude of IRH1. Stimulation of phosphatidylinositol turnover will probably be responsible for the suppression.

Animals↗
PubMed1992

Identification of two enhancer elements in the gene encoding the type 1 glucose transporter from the mouse which are responsive to serum, growth factor, and oncogenes.

The type 1 glucose transporter (GLUT1) gene encodes an integral membrane glycoprotein responsible for facilitating transfer of glucose across plasma membrane and is rapidly activated by serum, growth factors, and by oncogenic transformation. To elucidate the molecular mechanisms of regulation of GLUT1 gene expression, we isolated and characterized the mouse GLUT1 gene. DNA elements regulating transcription of the gene were analyzed in transient expression assays after transfection of NIH/3T3 cells with a low background chloramphenicol acetyltransferase (CAT) vector system pSVOOCAT. We identified two enhancer elements; the first one is located 2.7 kilobases upstream of the cap site of the gene which contains the homologous sequences with two 12-O-tetradecanoylphorbol-13-acetate-responsive elements (TREs), a serum response element, a cyclic AMP-responsive element (CRE) and three GC boxes, and the second one is located in the second intron of the gene which contains the homologous sequences with two TREs and one CRE. With the promoter alone the transcription of the gene is activated by src, only slightly activated by ras and is not activated by serum and platelet-derived growth factor. When the gene is accompanied by one of these enhancers, the transcription is activated by all these stimuli.

3T3 Cells↗
PubMed1992

Barbiturates suppress glucose utilization by inhibition of hexokinase in neuroblastoma cells.

Exposure to the pentobarbital potently inhibited the 2-deoxy glucose uptake in cultured neuroblastoma cells. The inhibition was assumed to be due to saturation of the uptake in the early stage where the incorporation was linear in the nontreated cells. On the contrary, the incorporation of 3-O-methyl glucose, another glucose analog which is not phosphorylated by hexokinase, was not altered by the treatment with pentobarbital. These results suggest that the suppression of hexokinase is involved in the above-mentioned effect of pentobarbital.

3-O-Methylglucose↗
PubMed1992

Insulin secretion from pancreatic B cells caused by L-arginine-derived nitrogen oxides.

L-arginine causes insulin release from pancreatic B cells. Data from three model systems support the hypothesis that L-arginine-derived nitrogen oxides (NOs) mediate insulin release stimulated by L-arginine in the presence of D-glucose and by the hypoglycemic drug tolbutamide. The formation of NO in pancreatic B cells was detected both chemically and by the NO-induced accumulation of guanosine 3',5'-monophosphate. NG-substituted L-arginine analogs inhibited the release of both insulin and NO. Protein immunoblot and histochemical analysis with antiserum to type I NO synthase suggest that the formation of NO in pancreatic B cells is catalyzed by an NADPH- (reduced form of nicotinamide adenine dinucleotide phosphate), Ca2+/calmodulin-dependent type I NO synthase of about 150 kilodaltons.

Amino Acid Oxidoreductases↗
PubMed1992

IgD myeloma presenting as a testicular tumor: establishment and characterization of an IgD-secreting myeloma cell line.

A 72-year-old man presented with a left testicular tumor and underwent orchiectomy. The tumor was massively infiltrated with myeloma cells bearing monoclonal cytoplasmic IgD lambda. Three months after orchiectomy, he developed huge abdominal masses and subsequently ascites containing numerous myeloma cells. An IgD-secreting myeloma cell line, designated delta-47, was established from the ascites. This cell line expressed CD4 and CD38, but lacked Fc and complement receptors, surface immunoglobulin, CD19, HLA-DR, and PCA-1. CD30 was detected on the cultured cells but not on the ascites tumor cells. Delta-47 cells secreted the same immunoglobulin (IgD lambda) as was found in the patient's serum. The light chain had a molecular weight of 35 kD which was larger than that of the normal light chain. Chromosome analysis of delta-47 revealed an aneuploid karyotype with complex abnormalities including 1q+, 2p+, and 14q+. To our knowledge, this is the only IgD-secreting myeloma cell line and would provide a useful tool for the study of IgD production and IgD myeloma.

ADP-ribosyl Cyclase↗
PubMed1992

Extracellular matrix in the rat spiral limbus.

The matrix of the spiral limbus is obviously a special form of the intercellular substance. In the present study, the rat's spiral limbus was investigated by electron microscopy after fixation with ruthenium red and tannic acid and immunofluorescence to demonstrate matrix components. Collagen types I, II, V, VI, VII, IX and XI and fibronectin were not observed. Collagen type II and cartilage-specific proteoglycans, however, occurred in large quantities. The basal lamina of interdental cells and inner sulcus cells did not contain any collagen type IV, while the basal lamina of the capillaries had only minor amounts. Laminin and nidogen appeared in large amounts in the basal lamina. After fixation with tannic acid, the matrix between the interdental cells and the capillaries contained 20- to 22-nm-thick single and irregularly running fibrils as well as plaques of a fine granular material. After fixation with ruthenium red, 30- to 60-nm-thick, electron-dense granules occurred and most probably consisted of proteoglycans. These findings indicate that the composition of the matrix of the spiral limbus is similar to that of cartilage but not identical.

Animals↗
PubMed1992

Secretory meningioma associated with numerous meningothelial rosettes.

A case of secretory meningioma with numerous meningothelial rosettes is reported. A 66-year-old man with moyamoya disease gradually developed skull deformity, and underwent surgery for the skull tumor overlying the hemisphere. Histological examination disclosed numerous meningothelial rosettes quite similar to those induced by subarachnoid injection of epinephrine and pseudopsammoma bodies described by Kepes. This may be the first case of meningioma associated with numerous rosette formations.

Aged↗
PubMed1992

MRI of anterior spinal artery syndrome of the cervical spinal cord.

Cervical spinal cord lesions in the anterior spinal artery syndrome were delineated on magnetic resonance images (MRI) in four patients. The lesion was always seen anteriorly in the cervical cord. On T2-weighted images, the lesions appeared hyperintense relative to the normal spinal cord, while on T1-weighted images, two chronic lesions appeared hypointense, with local atrophy of the cord. In one case, repeated T1-weighted images showed no signal abnormality 4 days after the ictus, but the lesion became hypointense 18 days later, when contrast enhancement was also recognized after injection of Gd-DTPA; this sequence of intensity changes was similar to that of cerebral infarction. The extent of the lesion seen MRI correlated closely with neurological findings in all cases. Although the findings may not be specific, MRI is now the modality of choice for confirming the diagnosis in patients suspected of having an anterior spinal artery syndrome.

Adult↗
PubMed1992

Verapamil attenuates postischemic oxidative injury in the rat liver.

We assessed the effects of the calcium channel blocker verapamil on postischemic oxidative injury in the rat liver. In the untreated rats, the values of tissue lipid peroxidation products (thiobarbituric acid-reactive substances) remained unchanged during 90 min of warm ischemia. However, the values increased significantly after the next 60 min of reperfusion compared with those in the sham-operated rats (P less than 0.01). Intravenous infusion of verapamil (5 micrograms.kg-1.min-1) significantly reduced the extent of lipid peroxidation during reperfusion compared with that in the untreated rats (P less than 0.02). The percentages of tissue water content and the serum lactate dehydrogenase activities after 60 min of reperfusion were significantly lower in the treated rats than in the untreated rats (P less than 0.02 and P less than 0.01, respectively). We also investigated the influence of verapamil on superoxide-generating activity determined by the superoxide-dependent cytochrome c reduction of peritoneal polymorphonuclear leukocytes (PMNs) harvested from normal, non-ischemic, and non-treated rats in vitro. This demonstrated that there was no apparent effect with the highest verapamil concentration level (8 microM) observed in the rat plasma during our experiment. These findings suggest that verapamil might reduce the postischemic oxidative injury in the rat liver by mechanisms perhaps not related to the suppression of rat PMNs superoxide-generating activity.

Animals↗
PubMed1992

A separating method for quantifying mucus glycoprotein localized in the different layer of rat gastric mucosa.

A method was devised for separating rat gastric mucosa into three layers each containing a different mucin species. The mucus gel (first layer) was removed by stirring the gastric mucosa in a solution of phosphate-buffered saline containing 2% N-acetylcysteine. The surface mucosa (second layer), rich in surface mucus cells, was then separated from the deep mucosa (third layer) containing mucus neck cells, by scraping with forceps. The effectiveness of this method was confirmed by light microscopical observation after GOCTS-PCS (dual staining by the galactose oxidase-cold thionin Schiff method and paradoxical concanavalin A method) and AB-PAS staining (dual staining with alcian blue and the periodic acid Schiff method). The fixed specimen of scraped mucus and cell debris was rich in AB-PAS and GOCTS positive mucus, but was hardly stained by PCS, indicating mucus derived from surface mucus cells to have been efficiently recovered from this preparation. The residual mucosa could be stained by PCS but hardly at all by AB-PAS or GOCTS. The lyophilized powder specimens obtained from the three different layers of rat gastric mucosa were used to extract and quantify mucus glycoprotein (mucin). This was done to examine changes in mucin content in the three layers of gastric mucosa one hour following the oral administration of 20% ethanol or 0.35 N hydrochloric acid, both mild irritants. Mucin content was noted to significantly increase in the first layer but hardly at all in the second layer. In the third layer, it decreased significantly by 0.35 N hydrochloric acid, but changed only slightly by 20% ethanol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Distribution of retinol-binding protein in the human digestive tract.

By employing polyclonal antibodies for retinol-binding protein (RBP), its distribution in the human pancreas and digestive tract mucosa was compared with those of transthyretin (TTR) and various peptide hormones. The materials used included surgically removed pancreas, esophagus, stomach, small and large intestines. Paraffin sections were stained by the indirect immunoenzyme method. The results indicate that RBP-containing cells are found in the pancreas and the gastrointestinal mucosa, but most frequently in the gastric antrum and duodenum. In the pancreas, RBP-containing cells are found in the islets and among acinar and ductal epithelial cells, and consistently stain for chromogranin A. RBP-containing cells in the gastrointestinal mucosa showed typical features of endocrine cells and also stained for chromogranin A. The distribution of TTR in these tissue sites resembled that of RBP, but the immunoreactive intensities of both peptides altered independently. Comparison of the distribution of RBP, TTR, and various gastrointestinal peptide hormones revealed that the distribution of RBP coincided with none of the other peptides, although some of the RBP-containing cells stained for most of the peptides examined and vice versa. These results suggest that RBP may be a consistent component of gastrointestinal endocrine cells.

Antibodies↗