Molecular characterization of human rotavirus VP4 genes by polymerase chain reaction and restriction fragment length polymorphism assay.
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Base Sequence↗
Biomedical subjects
M Iizuka
Publications and source records attributed to M Iizuka.
[Tumor-node-metastasis classification for thymic epitherial tumors].
We applied the tentative TNM classification of thymoma to 24 cases of IV b thymoma, 59 cases of thymic carcinoma, and 26 cases of thymic carcinoma (109 cases in total). This classification was useful in these cases because cases could be divided into different grades (e.g. N 0, N 1, N 2, N 3) of the factor N (lymph node metastasis) without any shift to particular grades. Based on this finding, we hereby propose a TNM classification of thymic epitherial tumors which was prepared by slightly modifying the tentative TNM classification of thymoma.
Carcinoid Tumor↗
[Albumin and fibronectin dynamics in an experimental adult respiratory distress syndrome model].
We produced an experimental adult respiratory distress syndrome model by intravenous administration of oleic acid (OA) in 30 dogs (Group I: 10 normal dogs; Group II: 10 dogs with 0.02 ml/kg of OA; Group III: 10 dogs with 0.04 ml/kg of OA; Group IV: 10 dogs with 0.08 ml/kg of OA). Changes in albumin (AL) and fibronectin (FN) in serum and BALF of these dogs were examined. The following results were obtained: 1) Serum values of AL and FN were significantly decreased after OA injection as compared with the baseline values. These changes were not correlated with the severity of pulmonary edema. 2) BALF values of AL and FN were significantly increased after OA injection as compared with the baseline values. Significant linear correlations were found between the BALF value of AL and ELWV, and between BALF value of AL and delta ELWV, [r = -0.682, 0.573 (p < 0.01)]. Significant linear correlations were also found between the BALF value of FN and ELWV, and the BALF value of FN and delta ELWV, [r = 0.722, 0.650 (p < 0.01)]. BALF value of AL increased significantly even with the low OA dose (0.02 ml/kg). Thus in comparison with BALF value of AL after OA injection, BALF value of FN was significantly higher than that in the normal group even when pulmonary edema were severe (Groups III and IV). We concluded that we could estimate the severity of pulmonary edema by measuring BALF value of AL and FN simultaneously.
Animals↗
Resetting from low threshold afferents of N-methyl-D-aspartate-induced locomotor rhythm in the isolated spinal cord-hindlimb preparation from newborn rats.
In this study we have investigated the effects of low threshold afferent stimulation on the centrally generated locomotor rhythm in an isolated spinal cord-hindlimb preparation from newborn (0-3 days old) rats. Locomotor activity was induced by bath application of N-methyl-D-aspartate (NMDA). Stimulation of low threshold afferents (below 2 times threshold (x T) for the incoming volley) in L2 and L3, but not L4 and L5 dorsal roots resets the ongoing rhythm. This is due to an abrupt excitation of the L2 and L3 ventral root bursts and an inhibition of the L5 ventral root burst on the ipsilateral side followed by reciprocal effects on the contralateral side. Similar effects were seen after stimulation of the quadriceps nerve with weak intensity (below 1.8 x T). We conclude that low threshold muscle afferents, possible group I afferents, have access to central pattern generators early in postnatal life and suggest that these findings may give an important opening in ontogenetic studies of how neural networks are assembled.
Afferent Pathways↗
Action of neopullulanase. Neopullulanase catalyzes both hydrolysis and transglycosylation at alpha-(1----4)- and alpha-(1----6)-glucosidic linkages.
The transglycosylation reaction catalyzed by neopullulanase was analyzed. Radioactive oligosaccharides were produced when the enzyme acted on maltotriose in the presence of [U-14C]glucose. Some of the radioactive oligosaccharides had only alpha-(1----4)-glucosidic linkages, but others were suggested to have alpha-(1----6)-glucosidic linkages. The existence of alpha-(1----6)-glucosidic linkages in the products from maltotriose with neopullulanase was proven by proton NMR spectroscopy and methylation analysis. We previously reported that the one active center of neopullulanase catalyzes the hydrolysis of alpha-(1----4)- and alpha-(1----6)-glucosidic linkages (Kuriki, T., Takata, H., Okada, S., and Imanaka, T. (1991) J. Bacteriol. 173,6147-6152). These facts proved that neopullulanase catalyzed all four types of reactions: hydrolysis of alpha-(1----4)-glucosidic linkage, hydrolysis of alpha-(1----6)-glucosidic linkage, transglycosylation to form alpha-(1----4)-glucosidic linkage, and transglycosylation to form alpha-(1----6)-glucosidic linkage. The four reactions are typically catalyzed by alpha-amylase, pullulanase, cyclomaltodextrin glucanotransferase, and 1,4-alpha-D-glucan branching enzyme, respectively. These four enzymes have some structural similarities to one other, but reactions catalyzed by the enzymes are considered to be distinctive: the four reactions are individually catalyzed by each of the enzymes. The experimental results obtained from the analysis of the reaction of the neopullulanase exhibited that the four reactions can be catalyzed in the same mechanism.
1,4-alpha-Glucan Branching Enzyme↗
c-myc expression is down-regulated by cell-cell and cell-extracellular matrix contacts in normal hepatocytes, but not in hepatoma cells.
Primary culture of adult rat hepatocytes resulted in marked increase of c-myc expression within a few hours. The high level of c-myc mRNA was maintained throughout culture on collagen-coated dishes, but decreased greatly with time during culture on collagen-gel or matrigel. Expression of c-myc was also down-regulated at high cell density. The decrease in its expression appeared closely related to inhibitions of DNA synthesis and cell spreading. In contrast, hepatoma H4TG cells showed a high level of c-myc expression which was not affected by culture on any extracellular matrices examined or by the cell density. These results suggest that up-regulation of expression of the c-myc gene is linked to G0 to G1 transition during cell cycle progression, which in normal hepatocytes is strictly regulated by cell-cell and cell-extracellular matrix interactions, but that this control mechanism is defective in malignant hepatic tumor cells.
Animals↗
Differential regulation of thyrotropin-releasing hormone receptor mRNA levels by thyroid hormone in vivo and in vitro (GH3 cells).
We studied the effect of thyroid status on thyrotropin-releasing hormone receptor (TRH-R) mRNA levels both in vivo and in vitro (GH3 cells) using a cloned rat TRH-R cDNA by RT-PCR. Experimental hypothyroid rats were produced by total thyroidectomy and were then killed 7 days after the operation. TRH receptor binding in the anterior pituitary and serum TSH level were elevated approximately 2-fold and 8-fold, respectively, in 7 day thyroidectomized rats. TRH-R mRNA levels in hypothyroid rats were also increased significantly compared with those of normal rats. In GH3 cells, however, no significant change of TRH-R mRNA level was observed between cultures treated with triiodothyronine (T3, 10(-9) and 10(-7) M) and the untreated group. The present data indicate that 1) the in vivo effects of thyroid status on TRH-R mRNA levels differ from the in vitro one, and that 2) the down regulation of TRH-R binding by thyroid hormone in GH3 cells may be mediated by translational or post-translational mechanisms.
Amino Acid Sequence↗
Active movement of cardiac myosin on Characeae actin cables.
The active sliding of cardiac myosin on actin cables was studied using an in vitro movement assay. Cardiac myosin prepared from either adult rabbit or rat hearts was mixed with small latex beads to coat them. Actin cables were obtained from the internodal cells of green algae, Characeae. When the myosin-coated beads suspended in physiological buffer were introduced into the internodal cells, the myosin started to interact with the actin causing the beads to move. The sliding movement of the beads was observed under microscopy and the sliding velocity measured. The observed movement was smooth and the velocity was constant over a long distance. The movement was physiological in nature: a) it was ATP-dependent, but above a certain level of ATP, the velocity was constant; b) the velocity was maximum at pH 7.0, and decreased in both acidic and alkaline conditions. The average sliding velocity of cardiac myosin obtained from rabbit ventricles (0.31 +/- 0.11 micron/s) was slower than that from rat ventricles (1.04 +/- 0.26 micron/s) reflecting the lower ATPase activity of rabbit cardiac myosin. This assay system is considered to be a useful tool linking biochemistry and physiology at the molecular level.
Actins↗
Effects of new intravascular contrast agents on [Ca2+]i transients and contraction in cultured ventricular myocytes.
We examined the effects of four kinds of intravascular contrast agents (amidtrizoic acid, iohexol, iopamidol, and ioxaglic acid) on [Ca2+]i transients (indo-1 fluorescence) and cell contraction (video motion analyzer), using cultured chick embryo ventricular myocytes. Exposure of ventricular myocytes to amidtrizoic acid (a conventional contrast agent) reduced the [Ca2+]i transients and the sensitivity of the contractile elements to [Ca2+]i. Ioxaglic acid (a low osmotic contrast agent) also reduced the [Ca2+]i transients, but did not significantly change the sensitivity of the contractile elements to [Ca2+]i. Neither iohexol nor iopamidol (nonionic contrast agents) reduced the [Ca2+]i transients, but both significantly decreased the sensitivity of the contractile elements to [Ca2+]i. A marked negative inotropic effect of amidtrizoic acid was caused by both calcium binding and hypertonicity. The less marked depression of contractility produced by ioxaglic acid is possibly the result of calcium binding, but is not caused by hypertonicity. The negative inotropism produced by nonionic contrast agents (iohexol and iopamidol) was due to hypertonicity, but not due to alterations in the [Ca2+]i transients. Exposure of ventricular myocytes to nonionic contrast agents (iohexol and iopamidol) slowed decay in the [Ca2+]i transients with increased end-diastolic [Ca2+]i. After washing out the nonionic contrast agents, these parameters returned to control levels. On the other hand, exposure to amidtrizoic acid decreased end-diastolic [Ca2+]i without changing decay time in the [Ca2+]i transients. After washing out amidtrizoic acid, there was a prolongation of half decay time in [Ca2+]i transients with a significant increase in end-diastolic [Ca2+]i and cell position. Diastolic dysfunction just after washout of amidtrizoic acid was possibly caused by an increase in [Na+]i due to sodium influx during exposure to the contrast agent.
Animals↗
IgG subclass-containing cells around the lymph follicle in the human intestine.
The authors previously reported the ring-like distribution of IgG-containing cells around the lymph follicle in both the small and large intestine. In the present study, the distribution of IgG subclass-containing cells around the lymph follicle was examined in both the small and large intestine, including Peyer's patches, by the indirect immunoperoxidase staining method. A ring-like distribution of IgG subclass-containing cells was observed in 14 out of 21 lymph follicles including 4 Peyer's patches (66.7%) in the terminal ileum, and 4 out of 7 (57.1%) in the large intestine. The percentages of IgG1-, IgG2-, IgG3-, and IgG4- containing cells around the lymph follicle in the terminal ileum were 27.6 +/- 11.6%, 51.9 +/- 15.4%, 16.5 +/- 10.2%, and 4.0 +/- 3.1%, respectively, and those in the large intestine were 22.9 +/- 15.4%, 47.4 +/- 14.9%, 11.2 +/- 4.1%, and 18.5 +/- 7.7%, respectively. Thus, among the IgG subclasses, IgG2-containing cells showed the most frequent ring-like distribution around the lymph follicle. The IgG2 predominance around the lymph follicle in the intestine was markedly different from reported IgG1 predominance in the lamina propria in the large intestine. This difference in IgG subclass distribution may suggest different origins of the IgG subclass-containing cells in the lamina propria and in areas around the lymph follicle.
Adolescent↗
Expression of MHC class II antigens (HLA-DR, -DP, and -DQ) on human gastric epithelium.
Class II antigen expression on gastric epithelium was investigated using an immunoperoxidase method in relation to the degree of inflammatory cell infiltration in the lamina propria. Sixty-six biopsy specimens from 43 patients with chronic gastritis were examined. The frequency of HLA-DR expression in specimens with cell infiltration was 94%, while that in specimens without cell infiltration was 24%. There was significant difference in the frequency of HLA-DR expression between the two groups (P less than 0.01). HLA-DR was most intensely expressed in the glandular neck portion. The frequency and extent of class II antigen expression on gastric epithelium with cell infiltration were in the following order: DR greater than DP greater than DQ. The extent of DR and DP, but not DQ expression generally paralleled the degree of cell infiltration. Intestinal metaplasia was found in 13 specimens. In the area of intestinal metaplasia, epithelial class II staining was absent except for one specimen. These results suggest that the respective genes of three class II antigens are regulated by different mechanisms and that an immunological mechanism plays a role in the pathogenesis of gastritis.
Epithelium↗
Cloning of the mouse hypothalamic preprothyrotropin-releasing hormone (TRH) cDNA and tissue distribution of its mRNA.
A complementary DNA (cDNA) for mouse hypothalamic preprothyrotropin-releasing hormone (TRH) was isolated and characterized using three different combinations of the polymerase chain reaction (PCR). Using this cDNA, we examined the tissue distribution of expression of the mouse preproTRH gene and evaluated the evolutionary basis of the preproTRH gene by comparison of the cloned sequence with sequences of preproTRH in other species. The deduced protein sequence of the mouse preproTRH contained 256 amino acids featured by possessing an insertion of one amino acid as compared with that of rat preproTRH. Five repetitive copies of the TRH progenitor sequence (Lys-Arg-Gln-His-Pro-Gly-Arg/Lys-Arg) were found in the mouse preproTRH. Northern blot analysis showed an apparent single band of hypothalamic mRNA of approximately 1600 base pairs in length. The homology of the coding region of the mouse preproTRH with the rat and human preproTRH is 92 and 65% at the nucleic acid level, respectively, and 88 and 56% at the amino acid level, respectively. By means of the PCR procedure, a characteristic expression of the preproTRH mRNA was observed solely in the mouse hypothalamus and testis. Moreover, it was noteworthy to find that the degree of homology to the region containing the sixth TRH-coding sequence of the human preproTRH was higher in the mouse preproTRH than the rat counterpart.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗
Cloning and polymerase chain reaction-single-strand conformation polymorphism analysis of anonymous Alu repeats on chromosome 11.
We have shown that many of the Alu repeats found in the GenBank database are polymorphic and that this polymorphism can be detected by a simple technique, single-strand conformation polymorphism (SSCP) analysis, after polymerase chain reaction (PCR) amplification of each repeat from DNA of individuals. Here, we describe a method for collecting many anonymous Alu repeats and their flanks in a chromosome-specific phage library and cloning them into plasmids. The flanking single-copy sequences of each repeat in the plasmid were then determined, and 20mer to 30mer segments of these sequences were used as primers for the PCR-SSCP analysis. Many new polymorphic DNA markers on chromosome 11 were obtained with this method. These markers can also serve as sequence-tagged sites for physical mapping of the genome.
Bacteriophages↗
Analysis of the TSH receptor gene structure in various thyroid disorders: DNA from thyroid adenomas can have large insertions or deletions.
We examined the structure of the TSH receptor gene in various thyroid disorders by a restriction fragment length polymorphism (RFLP) study with a cloned human TSH receptor cDNA as a probe. Southern blot analysis of DNAs in peripheral white blood cells obtained from normal individuals revealed a single band in each of several restriction enzyme digestions, indicating that the TSH receptor gene is a single copy gene in the human genome. Although RFLPs were not detected in peripheral blood cells and thyroid tissues in patients with Graves' disease, thyroid carcinomas, or subacute thyroiditis, significant RFLPs were found in 2 of 6 patients with adenoma in all restriction enzyme digestions examined. Moreover, these RFLPs were heterozygous and adenoma specific, and these additional bands in adenoma were amplified in both cases. We conclude that there are no major abnormalities in the structure of the TSH receptor gene in patients with Graves' disease, thyroid carcinoma, or subacute thyroiditis, although there may be a possibility of point mutations, small insertions, or deletions that cannot be detected by RFLP studies, and that there are large insertions or deletions in the region, including the TSH receptor gene, in some patients with thyroid adenoma.
Blotting, Southern↗
Persistence of repeated sequences that evolve by replication slippage.
The evolution of short repeated sequences by replication slippage under the assumption of selective neutrality is modeled using a linear birth and death process. The equilibrium distribution, the distribution of the life expectancy of a repeated sequence when the process starts from two repeats, the age distribution of repeats, the probability of obtaining two genes with i and j copies which diverged t generations ago and the conditional variance of copy number given the repeat number is more than one are computed. The distributions of life expectancy and age are shown to have long tails. Also the statistic which estimates the conditional variance is shown to have a large coefficient of variation. Using these theoretical results, we develop an approximate test of our model and analyze persistent repeated sequences found in the primate beta-globin gene region and Oenothera chloroplast DNA which are polymorphic within species. We found one sequence in Oenothera chloroplast DNA which does not fit to our neutral model.
Animals↗
Sliding velocity of isolated rabbit cardiac myosin correlates with isozyme distribution.
To investigate the relationship between the mechanical and biochemical properties of cardiac myosin, the sliding velocity of isolated cardiac myosin obtained from both euthyroid and hyperthyroid rabbits on actin cables was measured with an in vitro motility assay system. Ten rabbits (T) were treated with L-thyroxine to induce hyperthyroidism, and eight nontreated animals (N) were used as controls. Myosin was purified from the left ventricles of anesthetized animals. Myosin isozyme content was analyzed by the pyrophosphate gel electrophoresis method, and myosin adenosinetriphosphatase (ATPase) activity was determined on the same sample. Long well-organized actin cables of green algae, Nitellopsis, were used in the in vitro motility assay. Small latex beads were coated with purified cardiac myosin and introduced onto the Nitellopsis actin cables. Active unidirectional movement of the beads on the actin cables was observed under a photomicroscope, and the velocity was measured. The velocity was dependent on ATP concentrations, and the optimal pH for bead movement was approximately 7.0-7.5. The mean velocity was higher in T than in N (0.66 +/- 0.12 vs. 0.32 +/- 0.09 micron/s, P less than 0.01). Both Ca(2+)-activated ATPase activity and the percentage of alpha-myosin heavy chain were also higher in T than in N (0.691 +/- 0.072 vs. 0.335 +/- 0.072 microM Pi.mg-1.min-1, P less than 0.01, and 79 +/- 12 vs. 26 +/- 7%, P less than 0.01, respectively). The velocity of myosin closely correlated with both Ca(+2)-activated myosin ATPase activity (r = 0.87, P less than 0.01) and the percentage of alpha-myosin heavy chain (r = 0.87, P less than 0.01).
Animals↗
Cardiac adaptation and its limitation in an experimental model of congestive heart failure.
To elucidate mechanisms of adaptation and maladaptation in heart failure, abnormalities of left ventricular function and their relationships to myocardial contractile protein were studied in the Syrian hamster Bio 14.6. Left ventricular and heart weights were both increased in 20-week-old cardiomyopathic hamsters, indicating cardiac hypertrophy as a compensatory mechanism to the disease process of cardiomyopathy. However further increase in the left ventricular weight was not observed in older (40-week-old) cardiomyopathic hamsters. On the other hand left ventricular volume and volume/mass ratio were increased progressively. Correspondingly, V3 type myosin was increased and myosin sliding velocity was decreased. Left ventricular function of cardiomyopathic hamsters evaluated using an isovolumically beating perfused heart preparation was depressed, and this functional impairment was also progressive. Chronic administration of metoprolol, a beta-blocking agent, induced further increase in left ventricular volume and mass without changing left ventricular function and myosin isozyme pattern. Thus in cardiomyopathic hamsters, left ventricular function progressively deteriorates in spite of a variety of adaptive mechanisms, and remodeling occurs.
Adaptation, Physiological↗
[Effect on hemodynamic parameters and exercise tolerance by PTMC].
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Adult↗