Sequence of a 42-kb mouse region containing the imprinted H19 locus: identification of a novel muscle-specific transcription unit showing biallelic expression.
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Alleles↗
Biomedical subjects
R Kato
Publications and source records attributed to R Kato.
Mesangial cell apoptosis induced by a fibronectin fragment.
We previously showed that in passive Heymann nephritis (PHN) rats, a large quantity of fibronectin (FN) fragments containing the central cell-binding (CCB) domain and adjacent domains are generated in the kidney and excreted into urine (Nishizawa et al., Biol Pharm Bull 1998; 21: 429-433). To ascertain whether the FN fragments could affect the progression of PHN, we investigated the effect of a 150 K FN fragment containing the CCB and carboxyl-terminal heparin-binding (Hep 2) domains on cultured rat mesangial cells. When rat mesangial cells cultured on FN-coated plates were exposed to the 150 K FN fragment, some mesangial cells detached from the FN substrate and then underwent apoptosis as judged by nuclear and DNA fragmentations. The 150 K FN fragment competitively inhibited the mesangial cell adhesion to the FN substrate in a dose-dependent manner. Furthermore, gelatinzymography of the conditioned medium of mesangial cells showed that the 150 K FN fragment induced and/or potentiated the extracellular matrix (ECM)-degrading proteinases including matrix metalloproteinases (MMPs) of mesangial cells. These results indicate that the 150 K FN fragment may elicit mesangial cell apoptosis by disrupting the mesangial cell adhesion through two distinct ways: the inhibition of mesangial cell adhesion and the ECM-degradation by the 150 K FN fragment-induced MMPs. Thus, FN fragments containing the CCB and adjacent domains generated in the kidneys of PHN rats may be involved in the evolution of the renal injury.
Journal Article↗
Early and late post-ischaemic recovery of contractile function is affected to different degrees by isoflurane and halothane in the anaesthetized rabbit model.
The protective efficacy of halogenated anaesthetics on myocardial injury has never been compared during early reperfusion and late reperfusion in an in vivo animal model. We compared recovery of left ventricular function under isoflurane (0.5 MAC) and halothane (0.5 MAC) anaesthesia after a brief period of regional ischaemia (15 min) in acutely instrumented rabbits. Rabbits were instrumented for the measurement of regional segment length and left ventricular pressure. Rabbits receiving isoflurane showed greater recovery of systolic shortening fraction (%SS) both during early and late reperfusion compared with halothane anaesthesia. Isoflurane protected the post-ischaemic myocardium to a greater extent than halothane anaesthesia. Early recovery of contractile function may be a predictor of contractile recovery during the later stages of reperfusion.
Anesthetics, Inhalation↗
Milrinone decreases both pulmonary arterial and venous resistances in the hypoxic dog.
We have studied the effect of milrinone on pulmonary vascular resistance (PVR) in dogs with hypoxic pulmonary vasoconstriction (HPV). Using a pulmonary arterial occlusion method, we measured effective pulmonary capillary pressure (Pcap) by which total PVR was partitioned into arterial (PVRa) and venous (PVRv) components. Hypoxic ventilation (FIO2 = 0.11-0.13) produced significant increases in mean pulmonary arterial pressure (PAP) and Pcap (P < 0.01) associated with increases in PVRa and PVRv (P < 0.01). During the hypoxic period, milrinone significantly decreased mean PAP and Pcap (P < 0.01), reflected in decreases in PVRa and PVRv (P < 0.01). The longitudinal distribution of PVR (PVRa/PVRv) remained unchanged throughout the experiment, indicating that HPV occurred equally in the arterial and venous segments and that milrinone-induced vasodilatation occurred equally in both segments. During hypoxia, milrinone did not produce an increase in cardiac output or a decrease in PaO2. Milrinone also produced significant decreases in mean systemic arterial pressure (P < 0.01) and systemic vascular resistance (P < 0.05) to a similar extent to the decreases in mean PAP and PVR, suggesting no selective dilating effect of milrinone on the pulmonary vasculature. These results indicate that in HPV, milrinone decreased the vascular tone of both pulmonary arterial and venous segments without increasing cardiac work or impairing pulmonary oxygenation. This suggests a potential for use in patients suffering from hypoxic pulmonary hypertension.
Animals↗
Macrofollicular variant of papillary thyroid carcinoma.
A rare case of a macrofollicular variant of papillary thyroid carcinoma occurring in an 18-year-old male is described. The extirpated tumor, 5.5 x 5.5 x 3.5 cm in size, was well demarcated and multinodular, and histopathologically showed a predominantly macrofollicular structure reminiscent of adenomatous goiter or macrofollicular adenoma. In the tumor tissue, however, there were several small foci of microfollicular or papillary structure with the nuclei characteristic of papillary carcinoma. Parts of the macrofollicular areas also showed similar nuclear characteristics with a transition to microfollicular or papillary areas. Incomplete capsular invasion and minimal vascular invasion were also present. Additional resected specimens contained small metastatic nodules in the residual left lobe and lymph nodes. Immunohistochemistry showed a small number of p53-positive tumor cells in the microfollicular or papillary areas. It is suggested that this tumor is a well-differentiated variant which should be distinguished from benign thyroid lesions, although there have been some cases of metastases which appear related to capsular and/or vascular invasion.
Adolescent↗
Heterogeneity of ictal SPECT findings in nine cases of West syndrome.
We evaluated the ictal and interictal single photon emission computed tomography (SPECT) of 9 patients with West syndrome (WS). In this group, we noted two clear patterns of cortical hyperperfusion and subcortical hyperperfusion in the ictal SPECT. Both patterns were different from the previously documented ictal patterns for complex partial seizures (CPS) or secondarily generalized seizures. Our results suggest that the tonic spasms of WS do not always have a single neurophysiological basis; e.g., patients with hemihypsarrhythmia and focal hypsarrhythmia did not show ictal hyperperfusion of the lesion with hypsarrhythmia. These findings indicate that the origin of hypsarrhythmia as an EEG feature and the origin of tonic spasms may be different in such patients. In particular, hypsarrhythmia appears to originate from cortical lesions, whereas the subcortical structures may be primarily responsible for the tonic spasms. Our report is the first published study of ictal SPECT in patients with WS.
Adolescent↗
A case report of myolysis during high-dose amiodarone therapy for uncontrolled ventricular tachycardia.
We report a rare case of a 41-year-old male patient, a professional musician, with dilated cardiomyopathy and sustained ventricular tachycardia (VT) that was refractory to class I antiarrhythmic drugs. Severe myolysis developed after 10 months' administration of amiodarone (400 mg/day) in combination with mexiletine (300 mg/day) and disopyramide (400 mg/day). He had been suffering from severe moving muscle pain and an extremely high (16,830) IU/ml) serum level of creatine kinase (CK). The dosage of amiodarone was reduced from 400 mg/day to 200 mg/day without reduction of mexiletine or disopyramide and the patient's symptoms diminished. However, sustained VT developed, and so the dosage of the drug was increased to 250 mg/day. The high serum level of CK also decreased and returned to the normal range after the reduction in amiodarone dosage. Electrophysiologic examination of moving muscle revealed normal motor and sensory conduction velocities and, furthermore, the electromyogram revealed normal potentials and normal motor units. We conclude that severe myolysis developed as a result of the high dose and chronic administration of amiodarone. This is the first report of a Japanese patient showing rare and serious adverse effects in response to amiodarone treatment.
Adult↗
Binding characteristics of antibodies to the TSH receptor.
We have used fragments of the TSH receptor (TSHR) expressed in E. coli as glutathione S-transferase fusion proteins to produce rabbit polyclonal antibodies and a panel (n=5) of monoclonal antibodies to the extracellular fragment of the TSHR. The binding characteristics of the antibodies to linear, conformational, glycosylated and unglycosylated forms of the receptor in different assay systems have been investigated. The reactivity of these antibodies with the TSHR was assessed by Western blotting with both native and recombinant human TSHR expressed in CHO cells, immunoprecipitation of 35S-labelled full-length TSHR produced in an in vitro transcription/ translation system, immunoprecipitation of 125I-TSH/TSHR complexes, inhibition of 125I-TSH binding to the TSHR and fluorescence activated cell sorter (FACS) analysis of binding to CHO-K1 cells expressing the TSHR on their cell surface. Fab fragments of monoclonal antibodies were isolated, labelled with 125I and used to determine the affinity constants of these antibodies with receptor, bound and free Fab being separated by polyethylene glycol (PEG) precipitation. Rabbit polyclonal and mouse monoclonal antibodies reacted with the TSHR in Western blotting and one monoclonal antibody (3C7) was able to inhibit 125I-TSH binding to native human TSHR (74% inhibition), recombinant human TSHR (84% inhibition) and porcine TSHR (65% inhibition). Affinity constant values for TSHR monoclonal antibody Fab fragments calculated using Scatchard analysis were about 10(7) M(-1). Four out of five monoclonal antibodies reacted in FACS analysis with TSHR expressed on the surface of CHO-K1 cells. The FACS unreactive monoclonal (3C7) bound well to detergent solubilised TSH receptors and this emphasised the importance of using a combination of FACS analysis and radioactively-labelled probes in analysis of the TSH receptor. The monoclonal antibodies produced in this study were found to be of relatively low affinity but proved useful for detection of the receptor by Western blotting and by FACS analysis.
Animals↗
[Fibroepithelial polyp of the renal pelvis. A case report].
Benign tumors of the renal pelvis are relatively rare, and only a few reports have been published so far. Recently we experienced a case of a 50-year-old woman with a fibroepithelial polyp in the left pelvis. Drip infusion pyelography and abdominal CT revealed a filling defect and tiny renal stones in the left pelvis under the study of her urinary blood occult. A transitional cell carcinoma of the renal pelvis was suspected, so a left total nephroureterectomy was done. The pathological diagnosis of this tumor was fibroepithelial polyp. As it is said that preoperative diagnosis of such a polyp is difficult, preoperative ureteroscopy or perioperative pathological diagnosis by frozen sections should be attempted. But it is difficult to avoid a nephroureterectomy because low incidence of the disease.
Female↗
[A case of complete mediastinal goiter located in the retrotracheal region: review on reported cases from 1986 to 1997 in Japan].
A 66-year-old man was admitted to our hospital as a result of an abnormal shadow which was observed on his chest X-ray. A chest CT scan and chest MRI revealed an upper mediastinal tumor. The tumor was located in the retrotracheal region and resected completely following a thoracotomy. Histological examination of the tumor revealed follicular adenoma of the thyroid gland. Complete mediastinal goiter is a relatively rare lesion, with only 59 cases (including our case) in Japan prior to 1997. Only two cases were reviewed, in which the tumors were located in the retrotracheal region, out of the 59 cases in Japan.
Adenoma↗
[Different therapeutic approaches for patients with bronchogenic cysts within the esophageal wall].
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Adult↗
A method to differentiate between thyroglobulin derived from normal thyroid tissue and from thyroid carcinoma based on analysis of reactivity to lectins.
OBJECTIVE: The composition of sugar chains on thyroglobulin (Tg) produced in thyroid carcinoma cells (C-Tg) is different from Tg produced in normal thyroid tissues (N-Tg). In this study, we designed a new method for detecting Tg derived from thyroid carcinoma based on the differences between C-Tg and N-Tg in the reactivity with lectins. MATERIALS AND METHODS: Thyroglobulin preparations obtained from various thyroid tissues were incubated with lectins, and the amount of lectin-unbound Tg (ub-Tg) in the supernatant relative to Tg untreated with lectin was determined by enzyme-linked immunosorbent assay and expressed as ub-Tg(%). In addition, to study further the differences in glycosylation between C-Tg and N-Tg, concanavalin A binding to Tg digested with Staphylococcus aureus V8 protease was analyzed on nitrocellulose membrane after Western blotting. RESULTS: The ub-Tg(%) in C-Tg from papillary carcinoma was significantly higher than in Tg from Graves' disease, benign goiter, and normal thyroid tissue for both concanavalin A and ricinus communis agglutinin-120. Concanavalin A did not appear to bind to Tg from papillary carcinoma after V8 treatment by Western blot analysis. The ub-Tg(%) in Tg from follicular adenoma was significantly higher than C-Tg from follicular carcinoma, whereas there were no differences in ub-Tg(%) between follicular carcinoma and normal thyroid tissue in concanavalin A treatment. CONCLUSIONS: These results suggest our new methods can distinguish both between C-Tg from papillary carcinoma and N-Tg, and between follicular carcinoma and follicular adenoma in thyroid tissue specimens. Thus, this type of analysis may be applicable to differentiate C-Tg from N-Tg in thyroid aspirates for the adjunctive cytodiagnosis of thyroid carcinoma.
Biomarkers↗
Restoration of sexual behavior and dopaminergic neurotransmission by long term exogenous testosterone replacement in aged male rats.
PURPOSE: We investigated the effects of long-term testosterone replacement on copulatory behavior and dopaminergic neurotransmission in the medial preoptic area of aged male rats. MATERIALS AND METHODS: The rats were divided into 3 groups depending on testosterone replacement. Those in the long-term replacement group were castrated at the age of 12 months and received testosterone replacement thereafter for 12 months. In the short-term replacement group, rats were castrated at the age of 22 months and high or low dose testosterone replacement was done for 2 months. The control group consisted of aged rats 24 months old and young rats 12 weeks old, neither of which had been castrated or received testosterone replacement. We observed sexual behavior in rats of these groups. After a behavioral test, we measured the tissue concentration of dopamine in the MPOA and the change rate of the extracellular dopamine level induced by infusion of N-methyl-D-aspartic acid (NMDA) in the MPOA and compared the long-term replacement and no-replacement groups. RESULTS: The rats in the long-term replacement group showed a mount rate at the same level as that of young rats at 6 weeks after starting replacement and it was maintained to 24 months of age. Their mount rate was significantly higher than that of the rats with the short-term replacement. A significantly higher change rate of dopamine release was recognized in the long-term group; however, no significant difference in the concentration of dopamine was recognized between aged rats with long-term replacement and those without replacement. CONCLUSIONS: Aged rats (24 months old) with long-term testosterone replacement maintained almost the same level of mount behavior as young rats (12 weeks old). The results imply that long-term testosterone replacement may favorably alter the decline in the process of sexual activity with aging. The restoration by testosterone replacement of dopaminergic activity in the MPOA may be involved in the maintenance of sexual function in aged rats.
Aging↗
[Peripheral gamma delta T-cell lymphoma].
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Antigens, CD↗
Cloning and characterization of the uvrD gene from an extremely thermophilic bacterium, Thermus thermophilus HB8.
The uvrD gene encodes a DNA helicase which plays an important role in prokaryotic nucleotide (nt) excision repair, mismatch repair and DNA replication. A cosmid-based genomic DNA library for Thermus thermophilus (Tt) HB8 was constructed, and this was screened by Southern hybridization using a uvrD fragment amplified by PCR as the probe. The nt sequence of cloned Tt uvrD was then determined. Characteristic helicase motifs, made up of seven elements, were all conserved in the amino acid (aa) sequence of Tt UvrD. The aa sequence showed 41% homology with that of Escherichia coli (Ec). In the aa composition of Tt UvrD, the number of Asn, Gln, Met and Cys residues was decreased, and the number of Pro residues was increased. The distribution of Pro residues and recent data on X-ray crystallographic structure suggested the importance of the structural dynamics of the protein. These changes are thought to stabilize the native protein conformation against heat denaturation. Tt uvrD complemented the UV sensitivity of a Ec uvrD mutant. Thus, the thermophilic bacterium has a UvrD helicase, whose function is common to Ec UvrD.
Adenosine Triphosphatases↗
A 1.2-megabase BAC/PAC contig spanning the 14q13 breakpoint of t(2; 14) in a mirror-image polydactyly patient.
We previously assigned a 14q13 breakpoint of t(2; 14) in a patient with mirror-image polydactyly to a segment between two loci, AFM200ZH4 and D14S306, within a genetic distance of 0.6 cM. In the present study, we constructed a 1.2-Mb high-resolution physical map with a contig composed of 16 bacterial artificial chromosomes (BACs) and 6 P1-derived artificial chromosomes (PACs) at a region around the breakpoint, extending from D14S75 to D14S728 loci. Thirty-four novel sequence-tagged sites (STSs) were also characterized at this region. Of nine ESTs that had been mapped between D14S75 and D14S288, T99065 was confirmed to be in two BAC clones, B102 and B319. This BAC/PAC contig with STSs is useful for further genomic sequencing, for construction of a transcription map, and for the isolation of the putative gene for mirror-image polydactyly.
Chromosome Mapping↗
Domain structure of Thermus thermophilus UvrB protein. Similarity in domain structure to a helicase.
UvrB protein plays an essential role in the prokaryotic excision repair system. UvrB protein shows cryptic ATPase activity, DNA binding, helicase-like activity, and incision activity by interacting with UvrA or UvrC proteins. To reveal the structure-function relationship of this multifunctional protein, the domain structure of Thermus thermophilus UvrB protein (ttUvrB) was studied by limited proteolysis and denaturation experiments. Proteolytic profiles indicated that ttUvrB consists of four domains: the N domain (residues 2-105), M domain (106-455), C1 domain (456-590), and C2 domain (591-665). The properties of the proteolytic fragments indicated the involvement of the respective domains in the functions of the protein as follows: the N and C1 domains are necessary for ATPase activity, the C1 domain is indispensable for DNA binding, and the N and/or M domains are involved in UvrA binding. The structural stability of the C1 and C2 domains was higher than that of the N and M domains, which supports the proposed domain nature of ttUvrB. Based on these results and the crystal structure of PcrA helicase (Subramanya, H. S., Bird, L. E., Brannigan, J. A., and Wigley, D. B. (1996) Nature 384, 379-383), the domain organization of ttUvrB was proposed.
Adenosine Triphosphatases↗
Recombinant human TSH receptor expressed in E. coli.
We expressed the extracellular domain (20-408 aa, (T) of human TSH receptor (TSHR) in E. coli to detect TSHR autoantibodies (TRAb) and, moreover, we expressed the two portions (20-218 aa (5') and 217-408 aa (3')) of the extracellular domain thought to distinguish thyroid stimulating antibodies (TSAb) from blocking antibodies (TSBAb), using pGEX.3X as the expression vector. Using Western blotting analysis of the sera from patients with autoimmune thyroid disease, sera from Graves' patients and patients with idiopathic myxedema who had TSBAb reacted with the fusion protein (T), but none of the control sera reacted with it. We further evaluated whether or not the positive sear for T recognized fusion proteins (5') or (3'). The sera from Graves' patients reacted with both fusion proteins (5') and (3'). The sera from patients with idiopathic myxedema did not react with either of fusion proteins (5') or (3'). These findings suggest that these recombinant TSHR proteins could be used as antigens to detect TRAb, and differentiate TSABb from patients with idiopathic myxedema.
Antibodies, Blocking↗