PubMed Health⌕ Search

Biomedical subjects

T Taguchi

Publications and source records attributed to T Taguchi.

At least 271 records · Page 15Linked to original sources
PubMed1997

Immunohistochemical Detection of P-glycoprotein in Breast Cancer and Its Significance as a Prognostic Factor.

Overexpression of P-glycoprotein (Pgp) in tumors is one of the major mechanisms which mediates the multidrug resistance (MDR) phenotype. To evaluate the prognostic significance of Pgp in breast cancer, Pgp expression was examined in paraffin-embedded tissue sections of 94 breast cancer specimens by immunohistochemistry. Tissue specimens were obtained by mastectomy without preoperative chemotherapy. UIC2 monoclonal antibody which recognizes an extracellular epitope of human Pgp was employed. Of the 94 breast cancer specimens, 35(37.2%)were positive for Pgp expression. Pgp expression had no correlation with menopausal or hormone receptor status, axillary Iymph node involvement or tumor size. However, a significant correlation was observed between Pgp expression and disease relapse (p=0.0322). Pgp-positive patients showed a significantly shorter disease-free survival period than Pgp-negative patients by the Kaplan-Meier method (p=0.0433). These results suggest that immunohistochemical detection of Pgp in breast cancer tissue may have prognostic value after radical operation.

Journal Article↗
PubMed1997

The Clinical Utility of Docetaxel in Adriamycin-Resistant Breast Cancer.

Taxanes were developed as third-generation anticancer agents following methotrexate and adriamycin, two major chemotherapeutic agents for breast cancer. These agents have been studied to confirm antitumor effects in anthracycline-resistant patients and patients with liver metastasis. In this study, we examined the usefulness of taxanes, especially docetaxel, in chemotherapy for breast cancer by reviewing results in Japan and other countries. In a late phase II clinical study in Japan, the administration of 60 mg/m(2) /hr/3-4w of docetaxel (DOC) reduced tumor size in 50.4% of patients. In 6% of these patients, complete response (CR) was achieved. The duration of response was 14.7 weeks. Thirty-five percent of 26 primary adriamycin(ADM)-resistant patients responded to DOC treatment (CR:4.0%).

Journal Article↗
PubMed1997

Changes in fidelity levels of DNA polymerases alpha-1, alpha-2, and beta during ageing in rats.

DNA polymerases (deoxynucleoside-triphosphate:DNA deoxynucleotidyltransferase EC 2.7.7.7.) were extracted from the regenerating livers of rats of various ages. The extracts were separated into three DNA polymerase fractions (alpha-1, alpha-2, and beta) by phosphocellulose column chromatography, and their fidelity levels were then monitored with the synthetic template-primer, poly (dA-dT), poly dA-dT10, or poly dC-poly dG. The fidelity levels of the three DNA polymerases from regenerating liver of rats younger than 20 months were high, while those of DNA polymerases from rats older than 20 months were significantly lower with similar profiles on all three template-primers. On the other hand, the fidelity levels of enzymes from 23- and 26-month-old rats were similar. These results indicate that the levels of error-prone DNA polymerases increase rapidly in the regenerating liver of rats from ages 20 to 23 months. This may due to the amplification of DNA polymerase gene mutations by an error-prone enzyme itself. However, the cells in which mutations in the functional gene occur may undergo cell death because the fidelity levels of the DNA polymerases in the older animals did not increase.

Aging↗
PubMed1997

Neurocrescin: a novel neurite-outgrowth factor secreted by muscle after denervation.

Regeneration of injured axons at neuromuscular junctions has been assumed to be regulated by extracellular factors that promote neurite outgrowth. We report here the cloning of a novel neurite outgrowth factor, designated neurocrescin, from chick denervated skeletal muscle. A recombinant neurocrescin promoted neurite outgrowth from cultured neurons of spinal cord and telencephalon of chick embryo. It was expressed predominantly in neural tissue and muscle, and was secreted extracellularly after intramolecular cleavage. This truncated form was detected in denervated muscle but not in innervated muscle. Thus, neurocrescin appears to be a novel neurite outgrowth factor that is secreted in an activity-dependent fashion. A highly homologous counterpart was also cloned from mouse brain.

Amino Acid Sequence↗
PubMed1997

Spatial distribution of corticospinal potentials following transcranial electric and magnetic stimulation in human spinal cord.

To investigate the spatial distribution of the human corticospinal tract in the spinal cord, evoked spinal cord potentials (ESCPs) following transcranial electrical and magnetic stimulation were recorded simultaneously from both the anterior and posterior epidural space in five anesthetized patients. One ESCP component following transcranial electrical stimulation (D-wave) and at least two ESCP components (initially D-wave and later I-wave) following transcranial magnetic stimulation were recorded in all subjects. The negative peak latency of all the potentials recorded from the posterior epidural space was the same as that recorded anteriorly. The amplitude ratio of the ESCP following electrical stimulation (posterior/anterior) was 1.10+/-0.12, while that of ESCPs following magnetic stimulation was 1.08+/-0.12 (N1) and 1.15+/-0.16 (N2). These results suggest that lateral corticospinal tract descending dorsolateral fasciculus in the spinal cord is main corticospinal pathway and spatial distribution of D and I-waves are similar in the human cervical cord.

Cerebral Cortex↗
PubMed1997

Photoaffinity labeling of peroxisome proliferator binding proteins in rat hepatocytes; dehydroepiandrosterone sulfate- and bezafibrate-binding proteins.

To detect the cellular sites which directly interact with peroxisome proliferators (PPs) and mediate their inducing effect on peroxisomal enzymes in rat hepatocytes, two kinds of radiolabeled ligands, AD12 (7alpha-N-(4-azido-2-hydroxy-5-iodo[125I]benzyl)-aminomethyl-5-and rostene-3beta-ol-17-one-O-3-sulfate) and BZ5 (2-[p-[2-(4'-azido-3',5'-diiodo[125I]benzamido-2'-hydroxy)ethyl]phenoxy] -2-methylpropionic acid), were developed for photoaffinity labeling. These compounds were derivatives of dehydroepiandrosterone sulfate (DHEAS) and bezafibrate, respectively, with an azido group as the photoreactive functional group. Upon UV-irradiation following incubation with rat liver cytosol and nuclei, both the ligands effectively radiolabeled several proteins analyzed by SDS-polyacrylamide gel electrophoresis/radioluminography. When [125I]AD12 was used at a concentration of 0.2 microM, two cytosolic proteins with molecular masses of 55 and 28 kDa and a nuclear protein of 40 kDa were specifically labeled, as coincubation with a 1000-fold excess of DHEAS inhibited labeling. Photoaffinity labeling of the cytosolic 28-kDa protein was also affected by Wy-14,643, but not by unsulfated dehydroepiandrosterone or androsterone sulfate, consistent with our previous findings obtained in competitive binding studies of [3H]DHEAS-binding detected in rat liver cytosol (Yamada et al. (1994) Biochim. Biophys. Acta 1224, 139-146). On the other hand, [125I]BZ5 specifically labeled a cytosolic protein of 31 kDa, which was inhibited by coincubation with bezafibrate, clofibric acid and Wy-14,643, but not with DHEAS. Thus, [125I]AD12 and [125I]BZ5 labeled several proteins which recognized DHEAS and bezafibrate, respectively, in rat liver cytosol and nuclei, providing a useful means to investigate PP-binding proteins.

Affinity Labels↗
PubMed1997

Identification of a gene containing zinc-finger motifs based on lost expression in malignantly transformed rat ovarian surface epithelial cells.

We have used a rat model of epithelial ovarian cancer to identify a gene that shows decreased or lost expression in five of eight independently transformed rat ovarian surface epithelial cell lines compared to the normal progenitor cells. Hence, we refer to this gene as Lot1 (lost on transformation 1; GenBank accession no. U72620). The most abundant transcript of the gene is approximately 6 kb. This sequence contains a 1749-nucleotide open reading frame and, within the 3' untranslated region, 22 near-perfect 60-70-bp repeats and adenine- and uracil-rich areas. The deduced amino acid sequence from the open reading frame contains seven zinc-finger motifs of the C2H2 type, as well as proline-, glutamine-, and glutamic acid-rich areas. The gene maps to the short arm of chromosome one in the rat. Lot1 shows a limited distribution of expression in normal rat tissues, including ovary, which shows abundant expression. Furthermore, examination of DNA derived from multiple species indicates that the gene is widely conserved.

Amino Acid Sequence↗
PubMed1997

A voltage- and K+-dependent K+ channel from a membrane fraction enriched in contractile vacuole of Dictyostelium discoideum.

We obtained a membrane fraction enriched in the contractile vacuole by aqueous-polymer two-phase partitioning and its channel activities were analysed by incorporating it into artificial planar lipid bilayers. In asymmetrical KCl solutions (cis, 300 mM/100 mM, trans), we observed single-channel currents of a highly K(+)-selective channel with slope conductance of 102 pS and reversal potential of -20.4 mV, which corresponded to PK+/PCl- = 7. They showed bursts separated by infrequent quiescent periods. At 0 mV the mean open time was 2.0 ms. Among monovalent cations, Na+ and Li+ were impermeable, whereas Rb+ showed permeability equivalent to that of K+, although the unitary conductance was apparently reduced when the current flowed from the Rb+ containing side, suggesting that Rb+ is a permeant blocking ion. The open probability within bursts remained constant at approx.0.6 as long as the holding potential was positive on the cis side with respect to the trans side, but it decreased to 0 at negative potential. This channel was blocked by submillimolar concentrations of quinine and 30 mM TEA+. The open probability-voltage relationship showed a striking dependency on the KCl concentration on either side. This channel may play a role in water transport in this organelle.

Animals↗
PubMed1997

Selective formation of silent synapses on immature postsynaptic cells in cocultures of chick neurons of different ages.

Glutamatergic synapses usually contain two types of ionotropic glutamate receptor, N-methyl-D-aspartate receptors (NMDARs) and non-NMDA receptors (non-NMDARs), and the ratio of these receptors is thought to be critical for synaptic plasticity. To determine whether or not the ratio of these receptors at synaptic sites is controlled by the developmental stage of postsynaptic neurons, we applied a dual whole-cell recording technique to a culture of dissociated chick cerebral neurons of different ages. We found that formation of synapses that contained both types of receptor required maturation of postsynaptic neurons. Moreover, during the early development of postsynaptic neurons, NMDARs were selectively present at synaptic sites prior to the presence of non-NMDARs, even though both types of receptor were expressed in functional form in the neuronal membranes.

Age Factors↗
PubMed1997

Coexisting peripheral nerve and cervical cord compression.

STUDY DESIGN: The authors investigated the clinical usefulness of recording motor evoked potentials after transcranial magnetic stimulation in coexisting peripheral nerve and cervical cord lesions. OBJECTIVE: To show that the measurement of central motor conduction time from the abductor policis brevis and the abductor digiti minimi can be used as a good screening method for double lesions involving peripheral nerves and the cervical cord. SUMMARY OF BACKGROUND DATA: Transcranial magnetic stimulation has been used in the diagnosis of compressive cervical myelopathy. This technique could be useful in the assessment of patients with an entrapment neuropathy and cervical myelopathy. METHODS: Motor evoked potentials after transcranial magnetic stimulation, compound muscle action potentials, and F waves after supramaximal peripheral nerve stimulation were recorded from the abductor policis brevis and the abductor digiti minimi. The central motor conduction time was calculated by subtracting the peripheral conduction time from the motor evoked potentials latency. RESULTS: Ten patients with coexisting peripheral nerve and cervical cord lesions were evaluated. Two patients did not show satisfactory improvement after the decompression of the entrapment lesions, and six patients had hyperreflexia of lower limbs. In seven of these patients, the central motor conduction time was prolonged an average of 2.5 standard deviation of the normal value. The remaining two patients had spinal cord compression due to the ossification of the posterior longitudinal ligament. The spinal cord compression was demonstrated by magnetic resonance imaging, but the central motor conduction time was normal. Subjective symptoms improved in these two patients after decompressive surgery at the entrapment site alone. CONCLUSIONS: Measurement of the central motor conduction time using motor evoked potentials is an ideal diagnostic approach for patients with coexisting entrapment neuropathy and cervical cord compression.

Carpal Tunnel Syndrome↗
PubMed1997

Activity of UDP-GlcNAc:GlcNAc beta 1-->6(GlcNAc beta 1-->2) Man alpha 1-->R[GlcNAc to Man] beta 1-->4N-acetylglucosaminyltransferase VI (GnT VI) from the ovaries of Oryzias latipes (Medaka fish).

UDP-GlcNAc:GlcNAc beta 1-->(GlcNAc beta 1-->2)Man alpha 1-R[GlcNAc to Man] beta 1-->4N-acetylglucosaminyltransferase VI (GnT VI) activity was shown to be present in crude homogenates of Medaka fish (Oryzias latipes) ovaries using UDP-[14C]GlcNAc and synthetic GlcNAc beta 1-->6 (GlcNAc beta 1-->2)Man alpha 1-->6Glc beta 1-->octyl as substrates. Characterization of this activity showed a pH optimum at about pH 7.0 and an absolute requirement for divalent cations. The optimum concentration of Mn2+ was at about 25 mM. This finding is the first report on GnT VI activity in fish; the enzyme has previously been described only in avian tissues.

Animals↗
PubMed1997

Collagen-binding heat shock protein (HSP) 47 expression in anti-thymocyte serum (ATS)-induced glomerulonephritis.

An increased accumulation of extracellular matrix (ECM), predominantly collagens, is the main component of the expanded mesangial matrix in anti-thymocyte serum (ATS)-induced glomerulonephritis (GN). Heat shock protein (HSP) 47 is a collagen-binding stress protein and has been shown to have a specific role in the intracellular processing of procollagen molecules. It is a collagen-specific molecular chaperone in various organs, but its role in the kidney in relation to matrix expansion is not yet known. This study was designed to assess whether increased ECM accumulation in ATS-induced GN is associated with HSP47. The expression of type I, type III and type IV collagens, with their molecular chaperone HSP47, was investigated in ATS-induced GN rat kidneys. Fifteen male Wistar rats were divided into two groups: ATS-induced GN rats (group I) and age-matched controls (group II). GN was induced by injecting a single dose of ATS (0.8 ml/100 g body weight). All the rats were killed on the third and tenth day of the experiment. In group I, 3 days after ATS injection, histological examination revealed a reduction in glomerular cell number with mesangiolysis. However, 10 days after ATS injection, histologically severe mesangial cell proliferation with expansion of the mesangial matrix was noted in group I rats. By semiquantitative analysis, compared with controls, increased type I, type III, and type IV collagen immunostaining was observed in the expanded mesangial matrix in ATS-induced GN (group I) rats on day 10. Immunoreactive HSP47 expression was weak in the intraglomerular cells and was occasionally seen in the interstitial cells in control kidneys. In contrast, strong immunostaining for HSP47 was noted in the glomeruli of the ATS-treated rat kidneys on day 10. In this study, there was a parallel increase of various collagens and their molecular chaperone HSP47 in the ATS-treated rat kidneys. Compared with controls, no significant difference in HSP47 expression was found in the ATS-treated rat kidneys without mesangial matrix expansion (3 days after ATS injection). It is concluded that overexpression of HSP47 might play a significant role in the excessive assembly of collagens and could subsequently contribute to the expansion of mesangial matrix found in ATS-treated rat kidneys.

Animals↗
PubMed1997

Combined chromosome microdissection and comparative genomic hybridization detect multiple sites of amplification DNA in a human lung carcinoma cell line.

Chromosome microdissection-fluorescence in situ hybridization and comparative genomic hybridization (CGH) were performed in parallel to identify the native location of amplified DNA in a human non-small cell lung cancer (NSCLC) cell line exhibiting a homogeneously staining region (hsr) and double minutes (dmin). The native locations of microdissected DNA from the hsr and dmin were 7p12-13 and 8q24, respectively. Southern analysis revealed coamplification of EGFR (7p12) and MYC (8q24). CGH detected amplification of DNA not only from 7p12-13 and 8q24, but also from 9p24 and 10q22.

Blotting, Southern↗
PubMed1997

The distribution and co-localization of nitric oxide synthase and vasoactive intestinal polypeptide in nerves of the colons with Hirschsprung's disease.

The distribution and co-localization of nitric oxide synthase (NOS) and vasoactive intestinal polypeptide (VIP) were examined by means of immunohistochemistry and NADPH diaphorase (NADPH-d) histochemistry in the gut of patients with Hirschsprung's disease. In the normoganglionic segment, many nitrergic nerve cells were localized in Auerbach's plexus and nerve fibres were observed preferentially in the circular muscle. The submucosal nitrergic nerve cells were mainly situated in Schabadasch's plexus with occasional cells demonstrable in Meissner's plexus. NOS and VIP were co-localized in most ganglion cells of Auerbach's plexus. In the oligoganglionic segment, a marked reduction of NOS- and VIP- positive nerve cells and fibres was noticed in both the myenteric and submucosal plexuses, and nitrergic fibres had disappeared in the inner layer of the circular muscle. In the aganglionic segment, NOS and VIP were revealed only in extrinsic nerve fasciculi and rami and co-localized in a few fibres. From these observations, the inner layer of the circular muscle of the oligoganglionic segment and the whole of the muscularis propria of the aganglionic segment were considered to be totally lacking in nitrergic innervation. Nitrergic nerves of the human colon comprise both intrinsic and extrinsic elements and the majority of intrinsic nitrergic nerve cells contain VIP. Very low numbers of extrinsic nitrergic fibres contain VIP.

Child↗
PubMed1997

Failure in learning task and loss of cortical cholingergic fibers in microsphere-embolized rats.

The present study was undertaken to elucidate the pathological changes in learning and memory functions and in the metabolism of cortical cholinergic neurons following microsphere embolism in the rat. Microspheres (48 microm) were injected into the right internal carotid artery of rats. Learning and memory functions were measured 7 or more days after the embolism by active and passive avoidance, and water maze tasks. In the biochemical study, cortical acetylcholine and choline contents, and choline acetyltransferase activity were measured. Cortical acetylcholinesterase-containing fibers were quantitatively estimated in the embolized rat. The active and passive avoidance, and water maze tasks were impaired in the microsphere-embolized rat. In the histochemical study, the density of cortical acetylcholinesterase-containing fibers of the ipsilateral hemisphere of the microsphere-embolized rat was decreased, but cell density was unchanged. Furthermore, microsphere embolism decreased the cortical acetylcholine concentration and choline acetyltransferase activity and increased the choline concentration. The results suggest that microsphere embolism causes severe damage to cortical cholinergic neurons, which may be, at least in part, related to the impairment of learning and memory functions in the sustained brain ischemia.

Acetylcholine↗
PubMed1997

A prospective study on the prognostic significance of urokinase-type plasminogen activator levels in breast cancer tissue.

Urokinase-type plasminogen activator (u-PA), which cleaves plasminogen to yield plasmin, is a serine protease of fibrinolysis and is presumed to play a key role in extracellular proteolysis and facilitate the migration of cancer cells. This study was conducted prospectively to evaluate the prognostic significance of u-PA antigen level in breast cancer tissues. u-PA concentrations in the cytosol of 226 breast cancer tissues were determined prospectively by enzyme-linked immunosorbent assay using cytosol fractions prepared for steroid hormone assay. The median follow-up period of the patients was 60 months. Various prognostic factors were evaluated by univariate analysis or multivariate analysis using the Cox proportional-hazards method. Patients with primary breast cancer containing high levels of u-PA had a significantly shorter disease-free survival than patients with low levels of u-PA antigens. In multivariate analysis, a high level of u-PA was an independent risk factor for disease-free survival, being independent of age, axillary node status, and estrogen receptor status. Among the major prognostic factors, a high u-PA antigen level, lymph node involvement, and a positive estrogen receptor status were the most important for predicting relapse-free survival (P = 0.044, P < 0.0001, P = 0.0039). This first prospective study confirmed the prognostic significance of the u-PA antigen level in association with other major prognostic factors. The results of our present study suggest that u-PA in breast cancer tissue might be involved in breast cancer invasion and metastasis.

Age Factors↗