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Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

At least 91 records · Page 5Linked to original sources

Y-ligation: an efficient method for ligating single-stranded DNAs and RNAs with T4 RNA ligase.

Very efficient ligation of oligodeoxyribonucleotides was attained through a simple molecular construct, which is composed of one stem and two branches (Y-shape), with use of T4 RNA ligase. Single-stranded DNAs (naturally, RNAs also) of more than 100 nucleotides (even 800 nts) were considerably ligated, approximately as theoretically expected. Owing to the molecular construct adopted, such a tiny amount of ligation products could be amplified to a sufficient amount by PCR and then recovered as single-stranded DNAs. This advantage of being amplifiable is shown to be useful for both combinatorial chemistry and evolutionary molecular engineering, which deal with a pool of diversity molecules.

Biomedical Engineering↗

Radioreceptor assay analysis of tamsulosin and terazosin pharmacokinetics.

AIMS: A radioreceptor assay has been developed for alpha1-adrenoceptor subtypes and applied to a pharmacokinetic analysis of tamsulosin and terazosin. METHODS: Young, male, healthy volunteers received 0.4 mg tamsulosin (as Omnic modified release capsules) or 5 mg terazosin (as Flotrin tablets) in a randomized, cross-over design. Before and after 1, 3, 5, 7, 10 and 23.5 h plasma was analyzed by radioreceptor assay using cloned human alpha1A-, alpha1B- and alpha1D-adrenoceptors and specific h.p.l.c. analysis. RESULTS: Following ingestion of tamsulosin median peak plasma levels of 16 ng ml(-1) were reached after 5 h and declined to 2 ng ml(-1) at 23.5 h. The time course in the radioreceptor assay was similar, and at most time points binding to alpha1A-adrenoceptors was significantly greater than to alpha1B- and alpha1D-adrenoceptors. Following ingestion of terazosin median peak plasma levels of 91 ng ml(-1) were reached after 1 h and declined to 11 ng ml(-1) at 23.5 h. In the radioreceptor assay binding also peaked at 1 h and declined thereafter, but even after 23.5 h considerable binding activity remained detectable at all three subtypes. At most time points binding to the alpha1A- and alpha1D-adrenoceptor was significantly greater than to the alpha1B-adrenoceptor. CONCLUSIONS: We conclude that alpha1-adrenoceptor antagonist pharmacokinetics can be monitored by radioreceptor assays in a subtype-selective manner. Tamsulosin and terazosin exhibit subtype selective receptor binding ex vivo. The discordance between terazosin blood levels as determined by h.p.l.c. and radioreceptor assay at late time points indicates the possible involvement of metabolites in in vivo terazosin effects.

Administration, Oral↗

A new mammalian period gene predominantly expressed in the suprachiasmatic nucleus.

BACKGROUND: In mammals, two possible clock genes (Clock, Per1) have very recently been reported. mPer1 (the first identified mouse period gene), in particular, shows a circadian expression in suprachiasmatic nuclei (SCN), the mammalian circadian centre. However, only mPer1 and Clock as clock components may not be sufficient to understand all the events in circadian oscillation and entrainment. RESULTS: A mammalian period complementary DNA, mPer2, has been isolated from the mouse brain. The amino acid sequence of mPer2 is similar to mPer1 and Drosophila Period (dPer), indicating that mPer2 is a member of the family which contains mPer1, itself a homologue of dPer. mPer2 mRNA is predominantly expressed in SCN. A robust circadian rhythmic expression in the SCN supports the view that mPer2 is a clock gene. mPer2 is strongly expressed at the subjective afternoon in constant darkness, distinct from a morning-phase clock mPer1. Our precise quantitative in situ hybridizations have revealed that the peak expression of mPer2 transcripts is delayed by 8 h in LD (light-dark) or 4 h in DD (dark-dark) conditions when compared to mPer1. A short brief light exposure at the early subjective night, prompting a phase-shift in locomotor rhythms, induces a transient increase of mPer2 transcripts with delayed onset, as compared to mPer1 mRNA induction. Furthermore, mPer2 is co-expressed with mPer1 in single SCN cells. CONCLUSIONS: Mammalian period genes show molecular heterogeneity, each of which is composed of a different oscillator, and may serve to establish stable circadian rhythms in mammalian oscillating cells.

Amino Acid Sequence↗

Thyroid status affects the rat cardiac beta-adrenoceptor system transiently and time-dependently.

1. The aim of this study was to investigate the time-dependency of the influence of dysthyroid states on the beta-adrenoceptor system in rat heart left ventricle. Therefore, the influence of acute and chronic hyper- and hypothyroidism on beta-adrenoceptor-induced left ventricular responses, beta-adrenoceptor density, cardiac noradrenaline tissue concentrations, Gs alpha-proteins, and basal and stimulated adenylate cyclase activities was determined. 2. Hyperthyroid rats were obtained by feeding with thyroxine (T4)-containing rat-chow for 1, 4 and 8 weeks. Hypothyroidism was induced by adding 0.05% propylthiouracil (PTU) to the drinking water. Rats of varying ages were used in order to compensate for the differences in the duration of the treatments. Rats were aged 3 and 5 months at the end of the experiments. 3. Thyroxine treatment for 4 and 8 weeks increased the cardiac sensitivity to isoprenaline, but maximal induced inotropic responses were decreased. Cardiac ventricular beta-adrenoceptor density was increased only in rats treated with T4 for 1 week. This transient effect of hyperthyroidism on cardiac beta-adrenoceptor density was not observed in older rats. The PTU treatment resulted in a stable decrease of cardiac beta-adrenoceptor density. 4. Left ventricular tissue noradrenaline concentrations were unaffected by hyperthyroidism, where a decrease was observed in hypothyroid rats. Density of Gs alpha proteins was increased in hearts from chronic hyperthyroid rats. 5. These results indicate that the increased sensitivity to beta-adrenoceptor-mediated stimulation in chronic hyperthyroidism cannot be attributed to changes in cardiac beta-adrenoceptor density, but is probably caused by an enhanced content of Gs alpha. Accordingly, in hyperthyroidism, the beta-adrenoceptor system is influenced time-dependently, whereas hypothyroidism affects the beta-adrenoceptor system independent of time.

Adenylyl Cyclases↗

Primary malignant melanoma of the esophagus: report of a case successfully treated with pre- and post-operative adjuvant hormone-chemotherapy.

Primary malignant melanoma of the esophagus is a very rare and deadly disease, with a survival of 2.2% at 5 years and a median survival of about 10 months. The aggressive biological behavior of this disease and advanced stage at the time of diagnosis together with the lack of effective treatment have contributed to its poor prognosis. We present the case of a 45-year-old Japanese man diagnosed as having a primary melanoma of the esophagus by clinical evaluation and a histological examination of endoscopic biopsy specimens. A novel approach consisting of pre- and post-operative chemo-hormone therapy with dacarbazine, nimustine, cisplatin and tamoxifen in conjunction with radical esophagectomy accompanied by lymph node dissection was carried out. The tumor size was decreased to 70% by the pre-operative chemo-hormone therapy. During the post-operative 32 months of follow-up, no evidence of recurrence or metastatic disease has been found. Although this is only one case, the outcome observed suggests that the combination of pre- and post-operative chemo-hormone therapy and radical esophagectomy with lymph node dissection is a modality that can increase the possibility of curability or at least improve the survival of patients with primary melanoma of the esophagus.

Antineoplastic Combined Chemotherapy Protocols↗

Ultrastructure of murine tumour cell lines defective in MHC class I expression before and after interferon-gamma treatment.

Two tumour cell clones, 6D1 and 4C2 cells, which are defective both in the major histocompatibility gene complex (MHC) class I expression and in the endogenous antigen presentation, are recovered with interferon (IFN)-gamma treatment. The present study describes the ultrastructure of these cells by using scanning and transmission electron microscopy in relation to the effect of IFN-gamma treatment. The general morphology of these cells was found to be similar to each other and comparable to that of a tumour cell clone, 4A1 cells, of the same origin, normal in MHC class I expression; they exhibited a fibroblast-like appearance and had many blebs on all the cell surfaces, with desmosome-like junctions between cells. On IFN-gamma treatment, surface fine blebs appeared less, and mitochondria became more densely stained. Expression of MHC class I molecules on the cell surface was much higher in the IFN-gamma treated 6D1 and 4C2 cells than in untreated cells, when estimated by immunoelectron microscopy. The addition of an epitope peptide to these cells did not enhance the class I expression, which differed from other antigen presentation-defective cells such as RMA-S cells, nor change the cell surface morphology.

Animals↗

Prognostic factors after repeat hepatectomy for recurrent hepatocellular carcinoma.

OBJECTIVE: The aims of this study were to identify prognostic factors in patients who developed recurrent hepatocellular carcinoma (HCC) after repeat hepatectomy and to elucidate the role of multicentric occurrence in the second tumor after a first hepatectomy. SUMMARY BACKGROUND DATA: A repeat hepatectomy for recurrent HCC has been established as the most effective treatment modality, whenever it is possible. However, the prognostic factors for recurrent HCC after repeat hepatectomy have yet to be clarified. METHODS: Forty-one patients who underwent a curative repeat hepatectomy were retrospectively studied. Patient survival and disease-free survival after recurrence were univariately and multivariately analyzed using 38 clinicopathologic variables. The histologic grade of HCC at repeat hepatectomy was also compared with that at first hepatectomy. RESULTS: Patient survival after repeat hepatectomy did not differ substantially from that in 312 patients undergoing primary hepatectomy. However, the disease-free survival after repeat hepatectomy was significantly lower than that in patients with only a primary hepatectomy (p < 0.05). Multivariate analysis revealed only portal vein invasion in the first hepatectomy to be an independent and significantly poor prognostic factor. Regarding multicentric occurrence at repeat hepatectomy, only 6 of 40 patients (15%) whose specimens could be evaluated histologically were determined to be Edmondson and Steiner's Grade 1. CONCLUSIONS: The only prognostic factor identified in patients with recurrent HCC after repeat hepatectomy was portal vein invasion in the first hepatectomy. Most second tumors after the first hepatectomy are considered to be caused by metastatic recurrence, not by multicentric occurrence.

Algorithms↗

Sebaceous carcinoma of the submandibular gland with high-grade malignancy: report of a case.

A case of sebaceous carcinoma arising in the left submandibular gland of a 66-year-old man is reported. The clinical and pathological examinations revealed a carcinoma, which was to salivary gland in origin, with regional lymph nodal metastases. Pathological findings showed features of high-grade sebaceous carcinoma with spindle myoepitheliomatous differentiation. Neither squamous cell nor duct epithelial-like cell differentiation was noted. Immunohistochemically, tumor cells were positive for cytokeratin, S-100 protein and vimentin. Lipid was demonstrated in the cytoplasm of the tumor cells. Ultrastructurally, tumor cells contained numerous intracytoplasmic lipid droplets. Myoepitheliomatous differentiation is rare in sebaceous carcinoma of the salivary gland. Presented is the second reported case of sebaceous carcinoma arising in the submandibular gland.

Aged↗

Nm23-H1 expression in intrahepatic or extrahepatic metastases of hepatocellular carcinoma.

AIMS/BACKGROUND: Decreased expression of nm23, a putative metastasis suppressor gene, has been reported to be related to either intrahepatic metastasis or a poor prognosis in hepatocellular carcinoma (HCC). The aim of this study was to elucidate the true role of nm23-H1 expression in both intrahepatic and distant metastases of HCC. METHODS: Thirteen patients with single-nodule HCC, seven patients with HCC having satellite nodules and seven patients with HCCs having extrahepatic metastases were included in this study. The expression of nm23-H1 protein was immunohistochemically examined in both primary and metastatic nodules. RESULTS: Ten of 13 single-nodule HCCs were found to overexpress nm23-H1 protein. All main tumors, having satellite nodules, were found to overexpress nm23-H protein, except for two HCCs, which only partially expressed nm23-H1 protein. Regarding the nm23-H1 expression in intrahepatic metastases, most nodules overexpressed the protein. The expression of nm23-H1 was found to be low in only one intrahepatic metastasis specimen, while its primary tumor was also found to show a low expression of nm23-H1 protein. Microscopic portal vein invasion was found in three of the five patients studied, and all cancer cells in portal invasion overexpressed nm23-H1 protein. Nm23-H1 protein was expressed in all distant metastatic tumors and the staining intensity of most metastatic nodules was similar to that of the primary tumors. CONCLUSIONS: Our study demonstrated that nm23-H1 expression did not always decrease but instead tended to increase at both intrahepatic and extrahepatic metastatic sites. Based on these findings, nm23-H1 expression is not considered to be a reliable indicator of either intrahepatic or distant metastasis in HCC.

Adrenal Gland Neoplasms↗

Algorithm for image reconstruction in multi-slice helical CT.

Efforts are being made to develop a new type of CT system that can scan volumes over a large range within a short time with thin slice images. One of the most promising approaches is the combination of helical scanning with multi-slice CT, which involves several detector arrays stacked in the z direction. However, the algorithm for image reconstruction remains one of the biggest problems in multi-slice CT. Two helical interpolation methods for single-slice CT, 360LI and 180LI, were used a starting points and extended to multi-slice CT. The extended methods, however, had a serious image quality problem due to the following three reasons: (1) excessively close slice positions of the complementary and direct data, resulting in a larger sampling interval; (2) the existence of several discontinuous changeovers in pairs of data samples for interpolation; and (3) the existence of cone angles. Therefore we have proposed a new algorithm to overcome the problem. It consists of the following three parts: (1) optimized sampling scan; (2) filter interpolation; and (3) fan-beam reconstruction. Optimized sampling scan refers to a special type of multi-slice helical scan developed to shift the slice position of complementary data and to acquire data with a much smaller sampling interval in the z direction. Filter interpolation refers to a filtering process performed in the z direction using several data. The normal fan-beam reconstruction technique is used. The section sensitivity profile (SSP) and image quality for four-array multi-slice CT were investigated by computer simulations. Combinations of three types of optimized sampling scan and various filter widths were used. The algorithm enables us to achieve acceptable image quality and spatial resolution at a scanning speed that is about three times faster than that for single-slice CT. The noise characteristics show that the proposed algorithm efficiently utilizes the data collected with optimized sampling scan. The new algorithm allows suitable combinations of scan and filter parameters to be selected to meet the purpose of each examination.

Algorithms↗

Cloning and molecular analysis of the Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) biosynthesis genes in Pseudomonas sp. strain 61-3.

Two types of polyhydroxyalkanoate (PHA) biosynthesis gene loci (phb and pha) of Pseudomonas sp. strain 61-3, which produces a blend of poly(3-hydroxybutyrate) [P(3HB)] homopolymer and a random copolymer (poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) [P(3HB-co-3HA]) consisting of 3HA units of 4 to 12 carbon atoms, were cloned and analyzed at the molecular level. In the phb locus, three open reading frames encoding polyhydroxybutyrate (PHB) synthase (PhbCPs), beta-ketothiolase (PhbAPs), and NADPH-dependent acetoacetyl coenzyme A reductase (PhbBPs) were found. The genetic organization showed a putative promoter region, followed by phbBPs-phbAPs-phbCPs. Upstream from phbBPs was found the phbRPs gene, which exhibits significant similarity to members of the AraC/XylS family of transcriptional activators. The phbRPs gene was found to be transcribed in the opposite direction from the three structural genes. Cloning of phbRPs in a relatively high-copy vector in Pseudomonas sp. strain 61-3 elevated the levels of beta-galactosidase activity from a transcriptional phb promoter-lacZ fusion and also enhanced the 3HB fraction in the polyesters synthesized by this strain, suggesting that PhbRPs is a positive regulatory protein controlling the transcription of phbBACPs in this bacterium. In the pha locus, two genes encoding PHA synthases (PhaC1Ps and PhaC2Ps) were flanked by a PHA depolymerase gene (phaZPs), and two adjacent open reading frames (ORF1 and phaDPs), and the gene order was ORF1, phaC1Ps, phaZPs, phaC2Ps, and phaDPs. Heterologous expression of the cloned fragments in PHA-negative mutants of Pseudomonas putida and Ralstonia eutropha revealed that PHB synthase and two PHA synthases of Pseudomonas sp. strain 61-3 were specific for short chain length and both short and medium chain length 3HA units, respectively.

Acyltransferases↗

Skin penetration enhancing action of cis-unsaturated fatty acids with omega-9, and omega-12-chain lengths.

The skin penetrative action of high purity cis-omega-12-octadecenoic acid (petroselinic acid, HP-PSA) on rat skin was compared with that of high purity cis-omega-9-octadecenoic acid (oleic acid, HP-OA), following treatment of rat intact skin surface with either 0.05 M HP-PSA or HP-OA in propylene glycol (PG), using Fourier transform/attenuated total reflection (FT-IR/ATR) analysis. Both HP-PSA and HP-OA disordered the lipid structures of the stratum corneum region to a similar extent. Removal of the extractable lipids of the stratum corneum region was marked with HP-PSA/PG but was very slight upon HP-OA/PG treatment. The spectra of the amide II region which originated from proteins suggests that HP-PSA/PG more rapidly disordered the protein structures of both the stratum corneum and the dermis than HP-OA/PG. However, the extent of disordering of the protein structures was presumed to be similar between these two skin penetration enhancers at the maximum level. Enhancement of PG flux in the dermis showed strong positive correlation with the degree of dermis-disordering action of HP-PSA/PG and HP-OA/PG. These results demonstrate that HP-PSA, which has a double bond at an even numbered position (omega-12), more rapidly affects the perturbation of the structures of both the stratum corneum and the dermis than HP-OA, which has the double bond at an odd numbered position (omega-9). Differences in the physicochemical properties of HP-PSA and HP-OA which originate from differences in the double bond position most likely determine the efficacy of these compounds as skin penetration enhancers.

Animals↗

Cloning and characterization of the azurin iso-1 gene, concerned with the electron transport chain involved in methylamine/methanol oxidation in the obligate methylotroph Methylomonas sp. strain J.

Two azurin-type blue copper proteins, which is concerned with the electron transport chain involved in methylamine/methanol oxidation, have been found in the obligate methylotroph Methylomonas sp. strain J. The azurin iso-1 gene was cloned and sequenced to analyze the role in the electron transport chain. PCR products synthesized with primers based on the N- and C-terminal amino acid sequences of azurin iso-1 were used as probes for cloning. One complete open reading frame (the azurin iso-1 gene) and one partial orf (orf1) were found in a cloned Eco105I-HindIII fragment, pMAZ3, with a total of 1066 bp. The gene encoded 148 amino acid residues. The amino acid sequence after Ala-21, deduced from the nucleotide sequence, was identical to that of the azurin iso-1 protein. The gene was in a region separate from the mau gene cluster in the chromosome. Escherichia coli expressed azurin iso-1. The results of northern blotting analysis suggested that expression of the azurin iso-1 gene is regulated by a complex regulatory network controlling oxidation of methylamine or methanol in this strain; for example, copper ions affected the expression of the azurin iso-1 gene.

Amino Acid Sequence↗

L-type calcium channels in vascular smooth muscle cells from spontaneously hypertensive rats: effects of calcium agonist and antagonist.

Studies using the whole-cell voltage-clamp technique have demonstrated that L-type Ca2+ channel activity is increased in vascular smooth muscle cells from spontaneously hypertensive rats (SHR). We recorded L-type Ca2+ channel currents in cultured mesenteric artery smooth muscle cells from SHR and Wistar Kyoto (WKY) rats by using the cell-attached patch-clamp technique. Depolarizing voltage steps from a holding potential of -40 mV elicited voltage-dependent inward Ba2+ currents. There was no difference in the L-type Ca2+ channel I-V curve or in the open probability between SHR and WKY. The inward currents were inhibited by the Ca2+ antagonists nifedipine and verapamil, but were enhanced by the Ca2+ agonist Bay K 8644 in a concentration-dependent manner. The Bay K 8644-induced increase and the nifedipine-induced inhibition of the inward currents were enhanced in SHR, whereas there was no difference in the verapamil-induced inhibition of the currents between the two strains of rats. These results suggest that the enhanced L-type Ca2+ channel activity observed in vascular smooth muscle cells from SHR is not due to altered function of a single L-type Ca2+ channel. It appears that the sensitivity of dihydropyridine receptors in the channels is enhanced in SHR.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

Segregation of bovine viral diarrhea virus isolated in Japan into genotypes.

It was suggested that 3 strains of bovine viral diarrhea virus (BVDV) isolated from persistently infected calves in Tochigi prefecture in Japan belonged to BVDV type II. It was recognized lack of PstI site on the 5'-untranslated region of genome of them as well as BVDV type II reported previously. Inoculated with the 3 strains, the calves showed the mild decrease of platelet counts which was specific clinical sign of BVDV type II. We should report that the 3 strains were the first BVDV type II isolated in Japan. Neutralizing antibody titers of the antisera against the 3 strains using laboratory strains as neutralizing virus were lower than those of them using homologous strains. Therefore, it was indicated that the difference between BVDV type I and BVDV type II in the antigenicity.

Animals↗

[Prostatic cancer with cystic formation: a case report].

An 82-year-old man presented with a huge hypogastric tumor. A pelvic computed tomographic scan and magnetic resonance imaging revealed a multiple cystic mass 14 x 10 x 15 cm in diameter. The prostate specific antigen (PSA) value was elevated to 903 ng/ml. Histological examination of the needle biopsy specimens of the prostate revealed moderately differentiated adenocarcinoma. Bone scintigraphy showed a hot area in part of the costa. No other abnormalities were found. The tumor origin was suspected to be the prostate, but the possibility that it was another organ could not be denied completely since the tumor was located in the anterior portion above the bladder. Treatment with luteinizing hormone-releasing hormone agonist and diethylstilbestrol was initiated considering the patient's age. The PSA value returned to normal and the tumor size was reduced markedly after 28 weeks of therapy. Thirty-seven case of prostatic cancer with cystic formation in the Japanese literature are reviewed.

Adenocarcinoma↗