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Biomedical subjects

M Takamatsu

Publications and source records attributed to M Takamatsu.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Comparison between HGV genome and HGBV-C genome].

New hepatitis viruses, hepatitis G virus(HGV) and hepatitis GB virus C(HGBV-C), were reported from two groups of researchers. Now these two are thought to be similar but HGV genome(U44402) and HGBV-C genome(U36380) do not have the same sequence. We compare these two sequences in both nucleotide and aminoacid analyses. Homology of nucleotide between HGV and HGBV-C is 83.8% in 5'NC region, 88.8% in core, 85.1% in E1, 85.7% in E2, 85.1% in NS2-3, 84.5% in NS4A, 86.8% in NS4B-5A, 88.6% in NS5B and 18.0% in 3'NC. The length of 3'NC is quite different between HGV and HGBV-C. Homology of aminoacid between these two viruses is 82.9% in core region, 87.3% in E1, 91.0% in E2, 97.4% in NS2-3, 93.8% in NS4A, 96.2% in NS4B-5A and 96.6% in NS5B. Especially helicase and replicase regions are highly conserved in 99.0% and 92.7% of aminoacid homology, respectively.

Amino Acid Sequence↗
PubMed1996

Endoscopic injection sclerotherapy for esophageal variceal hemorrhage in a patient with idiopathic myelofibrosis.

A 74-year-old female with idiopathic myelofibrosis (IMF) was admitted to our hospital because of massive hematemesis and melena. Immediate upper gastrointestinal endoscopy revealed an intermittent spurting hemorrhage from extensive esophageal varices. Endoscopic injection sclerotherapy (EIS) was carried out and the bleeding ceased. After five courses of EIS, all the esophageal varices were eradicated. About 15 months later, the patient died, due to a cerebral hemorrhage, without further variceal bleeding. A postmortem examination was carried out and the portal hypertension was considered to be due not only to extramedullary hematopoiesis in the sinusoids, but also to increased splenic blood flow. We are confident that EIS is an effective therapeutic procedure for patients with IMF showing esophageal variceal hemorrhage. EIS should be the preferred choice of treatment for esophageal varices in patients with IMF, since it is less invasive than splenectomy.

Aged↗
PubMed1996

Ultrasound biomicroscopic study of ciliary body thickness after topical application of pharmacologic agents.

PURPOSE: To examine the changes in ciliary body thickness after topical application of pilocarpine, cyclopentolate hydrochloride, and PhXA41, a prostaglandin F2alpha analog. METHOD: We used high-frequency Humphrey UBM840 ultrasound biomicroscope to examine 36 healthy young Japanese subjects. RESULTS: The mean ciliary body thickness increased from 0.67 +/- 0.07 mm to 0.073 +/- 0.08 mm (P < .01) after application of 2% pilocarpine; 1% cyclopentolate hydrochloride and 0.005% PhXA41 decreased the mean ciliary body thickness from 0.75 +/- 0.07 mm to 0.69 +/- 0.05 mm (P < .05) and from 0.78 +/- 0.06 mm to 0.75 +/- 0.06 mm (P < .01), respectively. CONCLUSIONS: Our ultrasound study clearly indicates that pilocarpine increased comparative thickness of the ciliary body by 8.3%, whereas PhXA41 decreased comparative thickness by 3.3% in a manner similar to cyclopentolate hydrochloride.

Administration, Topical↗
PubMed1996

The kinase, SH3, and SH2 domains of Lck play critical roles in T-cell activation after ZAP-70 membrane localization.

Antigenic stimulation of the T-cell antigen receptor initiates signal transduction through the immunoreceptor tyrosine-based activation motifs (ITAMs). When its two tyrosines are phosphorylated, ITAM forms a binding site for ZAP-70, one of the cytoplasmic protein tyrosine kinases essential for T-cell activation. The signaling process that follows ZAP-70 binding to ITAM has been analyzed by the construction of fusion proteins that localize ZAP-70 to the plasma membrane. We found that membrane-localized forms of ZAP-70 induce late signaling events such as activation of nuclear factor of activated T cells without any stimulation. This activity was observed only when Lck was expressed and functional. In addition, each mutation that affects the function of Lck in the kinase, Src homology 2 (SH2), and SH3 domains greatly impaired the signaling ability of the chimeric protein. Therefore, Lck functions in multiple manners in T-cell activation for the steps following ZAP-70 binding to ITAM.

Humans↗
PubMed1996

[Effects of beta-adrenergic blockers on retinal circulation].

We evaluated the effects of 0.5% betaxolol hydrochloride and 0.5% timolol maleate on retinal blood flow. We measured the diameter of the retinal artery (Da) and vein (Dv), and retinal venous blood flow rate (V) in 8 healthy young volunteers by laser speckle velocimetry before and after the application of betaxolol or timolol topically to both eyes daily for one week. There were no any significant changes. Da before and after the application of betaxolol was 114.2 +/- 6.3 (mean +/- standard deviation) microns and 115.6 +/- 6.7 microns and before and after the application of timolol, 117.5 +/- 12.7 microns and 101.3 +/- 9.5 microns. Dv before and after the application of betaxolol was 149.5 +/- 11.1 microns and 148.4 +/- 13.3 microns, and before and after the application of timolol 148.5 +/- 9.2 microns and 146.2 +/- 10.3 microns. V before and after the application of timolol was 12.3 +/- 2.6 mm/s and 12.6 +/- 2.4 mm/s, and before and after the application of betaxolol, 11.6 +/- 1.5 mm/s and 11.4 +/- 2.1 mm/s. Thus one-week application of the beta-blockers, betaxolol and timolol did not change the retinal arterial or venous blood flow.

Adolescent↗
PubMed1995

Analysis of phosphorylation of tau with antibodies specific for phosphorylation sites.

Previously, we determined sites of tau protein phosphorylation by tau protein kinase (TPK) I/glycogen synthase kinase 3 beta (GSK-3 beta) and TPKII/(cyclin-dependent kinase 5 (CDK5) + p23). We prepared antibodies specific for these sites of tau phosphorylated by TPKI and TPKII, using chemically synthesized phosphopeptides as antigens. Each antibody specifically reacts with each phosphorylation site. With these antibodies, it was confirmed that TPKI and TPKII are responsible for these phosphorylation sites, as reported previously, except that Ser404 is also weakly phosphorylated by TPKI alone. It was also observed that TPKII-phosphorylation enhances TPKI-phosphorylation. These results indicate that these antibodies are useful tools for investigation of the phosphorylation of tau by TPKI and TPKII.

Amino Acid Sequence↗
PubMed1995

Involvement of tau protein kinase I in paired helical filament-like phosphorylation of the juvenile tau in rat brain.

tau protein kinase I (TPKI) phosphorylates tau and forms paired helical filament epitopes in vitro. We studied temporal expression and histochemical distribution of tau phosphoserine epitopes at sites known to be phosphorylated by TPKI. Antibodies directed against phosphorylated Ser199 (anti-PS 199) or phosphorylated Ser396 (C5 or anti-PS 396) were used. TPKI is abundantly expressed in the young rat brain and the highly phosphorylated juvenile form of tau occurs in the same period. The activity peak of TPKI coincided with the high level of phosphorylation of Ser199 and Ser396 in juvenile tau at around postnatal day 8. By immunohistochemistry on the hippocampus and neocortex of 3-11-day-old rats, phosphorylated Ser396 was found in young axonal tracts and neuropil, where TPKI immunoreactivity was also detected. TPKI and phospho-Ser199 immunoreactivities were also detected in the perikarya of pyramidal neurons. TPKI immunoreactivity had declined to a low level and phosphorylated serine immunoreactivities were undetectable in the sections of adult brain. These findings implicate TPKI in paired helical filament-like phosphorylation of juvenile form of tau in the developing brain.

Aging↗
PubMed1995

Emphysematous cholecystitis after endoscopic wallstent placement complicated by distal migration of the stent.

Endoscopic placement of Wallstents was thought to be a less invasive procedure, and in previous publications serious complications were infrequent. We report here on the case of a 58-year-old man with unresectable pancreatic cancer who developed emphysematous cholecystitis after endoscopic placement of a Wallstent, which was further complicated by distal migration of the stent. A second stent had to be placed into the first to fully bridge the malignant stricture. Three days later, the patient developed cholecystitis and septic complications, and he finally died of septic shock with disseminated intravascular coagulation. This previously unreported complication should be considered if abdominal pain and high fever develop after Wallstent placement.

Cholecystitis↗
PubMed1995

[Endoscopic placement of self-expandable metallic stents (Wallstent) for malignant biliary stenosis, with special reference to preventive endoscopic nasal bile drainage against acute obstruction after stenting].

From December 1993 to December 1994, we inserted 14 biliary endoprostheses (Wallstent) endoscopically in 12 consecutive patients (5 men and 7 women; 55-91 years [mean 69.8 years] of age) with malignant biliary stenosis. Successful placement of Wallstent was achieved in all 12 patients. Procedure related death was encountered in one patient (8.3%) who was complicated with emphysematous cholecystitis, combined with a slipping migration of the stent. In 11 of the 12 patients, serum bilirubin levels reduced to less than 2.0 mg/dl. Acute obstruction, which was defined as the obstruction of the stent within 24 hours after the stent placement, occurred in 2 patients (16.7%). Endoscopic nasal bile drainage (ENBD) following stent placement was performed in 4 patients and acute obstruction was not developed in these cases. After endoprosthesis 8 patients were discharged with 6-47 hospital days and the average hospitalized period excluding a case with cerebral infarction was 12.7 days. Excluding one procedure related death, 6 patients died of primary malignancy 39-189 days (average 90.7 days) after endoprosthesis and in 2 cases recurrence of jaundice was observed. The other 4 patients have been alive for 60-174 days (average 102.5 days) without jaundice. The survival rate of the all patients was 64% for 3 months and 32% for 6 months, respectively. In conclusion, we suggested that the endoscopic Wallstent placement would contribute to the improvement of the quality of life for patients with malignant biliary stenosis. However, acute obstruction may be developed in some cases. For the purpose of managing acute obstruction, we recommend ENBD for a few days following the placement of a Wallstent.

Acute Disease↗
PubMed1994

Precursor of cdk5 activator, the 23 kDa subunit of tau protein kinase II: its sequence and developmental change in brain.

Tau protein kinase II (TPKII) is shown by immunoprecipitation to be a complex composed of two subunits, a catalytic subunit, cdk5, and regulatory subunit, p23. By sequence analysis of p23 cDNA, p23 was found to occupy a region from the 99th amino acid residue to the C-terminus of a novel protein with a molecular weight of 34,000 Da, suggesting that this 34 kDa protein is a precursor of p23 (pre-p23). These findings suggest that p23 results from the processing of the precursor protein, pre-p23. The precursor mRNA was expressed most abundantly in rat brain just before and after birth. Expression of pre-p23, but not of cdk5, mRNA changed, coinciding with the developmental change of TPKII activity, suggesting that its expression controls the phosphorylation of tau by the TPKII/TPKI system in the neonatal brain. p23 appears to be a cdk5 activator in neuronal cells.

Amino Acid Sequence↗
PubMed1994

Identification of the 23 kDa subunit of tau protein kinase II as a putative activator of cdk5 in bovine brain.

Tau protein kinase II (TPKII) was reported previously to be composed of a neuron-rich cdc2-related kinase (PSSALRE/cdk5) and 23 kDa subunit. Here we show that the 23 kDa subunit is a putative activator for the kinase activity. Amino acid sequence analysis revealed that the protein was novel and included a partial similarity of amino acids to a cyclin box important for the interaction with cdc2-related kinase. These results suggest that the 23 kDa subunit, but not cyclin, activates cdk5 in neuronal cells, which no longer exhibit cell cycling but are terminally differentiated cells.

Amino Acid Sequence↗
PubMed1994

[Quantitative analysis of blood group antigen of transitional cell carcinoma of the urinary tract by flow cytometry].

We propose a new method of quantitative measurement of cell surface blood group antigen (BGA) in superficial transitional cell carcinoma (TCC) of the urinary tract by using flow cytometry. Flow cytometric analysis was performed on 22 cases of superficial urinary tract TCC registered at the department of Urology, Okayama University Hospital during April, 1992-Feb. 1993. Fresh samples were divided into two specimens. One specimen was fixed in 20% formalin and was subjected to immunohistochemical staining of BGA using avidine-biotine complex (ABC) method. The other specimen was dissociated into single cell with mincing. The single cell was further divided into two specimens. One specimen was incubated on ice with anti-ABH mouse monoclonal antibody (DAKO)as a primary antibody. The other specimen was incubated on ice with mouse IgM as a negative control. These two specimens were reacted with FITC-conjugated rabbit anti-mouse IgM and propidium iodide (PI). Next, these cells were subjected to the flow cytometry using FACStar (Becton & Dickinson). By gating on the bivariate display of FSC vs. FL2 (PI), all nucleated cells were obtained separately and the positive rate was measured. The positive rate of FCM was successfully correlated with the degree of immunohistochemical stain. Compared with immunohistochemical staining thus far, this new technique provides a way to standardize the quantitative measurement of BGA expressions.

ABO Blood-Group System↗
PubMed1993

A cdc2-related kinase PSSALRE/cdk5 is homologous with the 30 kDa subunit of tau protein kinase II, a proline-directed protein kinase associated with microtubule.

We previously reported that tau protein kinase II (TPKII) from bovine brain was composed of 30 kDa and 23 kDa subunits. The 30 kDa subunit of TPKII can be regarded as a catalytic subunit because of its ATP-binding activity. Antibodies directed against TPKII-phosphorylated tau also reacted with tau phosphorylated by cdc2 kinase obtained from starfish oocytes, indicating that TPKII and cdc2 kinase phosphorylate the same sites. We determined the amino acid sequence of the 30 kDa subunit and found it to be homologous with a cdc2-related kinase, PSSALRE/cdk5. Moreover, an antibody against PSSALRE/cdk5 reacted with the 30 kDa subunit. These results indicate that the 30 kDa subunit of TPKII is bovine homologue of PSSALRE/cdk5. Expression of the 30 kDa subunit mRNA was enhanced in juvenile rat brain. This result supports our previous hypothesis that the kinase works actively in juvenile brain.

Amino Acid Sequence↗
PubMed1993

Presence of env genes in members of the RTVL-H family of human endogenous retrovirus-like elements.

We have found that the RTVL-H family of human endogenous retrovirus-like elements was highly expressed in lung squamous cell carcinoma tissue and several human cell lines. We determined the nucleotide sequences of several cDNA clones and found a unique sequence that was not present in the published "prototypic" RTVL-H sequence. An open reading frame in this region encoded an amino acid sequence homologous to the conserved sequence in the transmembrane envelope protein of various retroviruses. Two genomic clones that encoded this sequence were obtained and sequenced. One RTVL-H element containing the env gene was 8.7 kilobase pairs in length. The putative env gene, consisting of about 1800 base pairs, had two open reading frames interrupted by a termination codon. The amino acid sequence of this region showed significant homology with those of other retroviral envelope proteins and contained eight potential glycosylation sites. There were estimated to be about 100 copies of RTVL-H elements containing the env gene per haploid human genome.

Amino Acid Sequence↗