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Biomedical subjects

T Taguchi

Publications and source records attributed to T Taguchi.

At least 253 records · Page 14Linked to original sources

Long-lasting enhancement of synaptic activity in dissociated cerebral neurons induced by brief exposure to Mg2+-free conditions.

The long-lasting enhancement of periodic clusters of spontaneous excitatory postsynaptic currents (SEPSCs) was examined in dissociated chick cerebral neurons that had been transiently exposed to Mg2+-free solution for 15 min. Since the enhancement was diminished by blockade of synaptic transmission, it clearly depended on synaptic activities. A specific antagonist of N-methyl-D-aspartate receptors (NMDARs) also inhibited the potentiations. Furthermore, the presence of inhibitors of protein and RNA synthesis in the Mg2+-free solution blocked the potentiation. In the potentiated neurons, the frequency of miniature excitatory postsynaptic currents (mEPSPs) increased. In addition, a diffusible molecule(s) that promoted the potentiation appeared to be involved in this phenomenon, since the conditioned medium of Mg2+-free treated neurons enhanced synaptic activity in other dish.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Changes in cholinergic neurons and failure in learning function after microsphere embolism-induced cerebral ischemia.

Central cholinergic neurons play an important role in learning and memory functions. The present study was undertaken to elucidate the pathological changes in learning function and acetylcholine metabolism of the cerebral cortex and hippocampus, following microsphere embolism in rats. Microspheres (48 microns) were injected into the right internal carotid artery of the rats. Learning function was determined using a passive avoidance task on the seventh day after the embolism. In the biochemical study, acetylcholine and choline contents, and choline acetyltransferase activity were measured in the cerebral cortex and hippocampus. Cortical acetylcholinesterase-containing fibers were quantitatively estimated in the embolized rat. Passive avoidance was impaired in the microsphere-embolized rat. Microsphere embolism decreased the acetylcholine concentration and choline acetyltransferase activity in the cerebral cortex and hippocampus. In the histochemical study, the length of cortical acetylcholinesterase-containing fibers was decreased, but cell density was unchanged in the ipsilateral hemisphere of the microsphere-embolized rat. The results suggest that microsphere embolism induces severe damage to cholinergic neurons, which may be related to the impairment of learning function in the ischemic brain.

Acetylcholine↗

Proton NMR study of triantennary complex type N-linked glycan chains: assignment of proton chemical shifts of the beta-Man residue in a basic unit of the triantennary glycan chain having a GlcNAc beta 1-->6 Man alpha 1-->6 Man beta-->sequence.

The chemical shifts of ring protons of the beta-Man residue in a triantennary complex type N-linked glycan chain having a GlcNAc beta 1-->6(GlcNAc beta 1-->2)Man alpha 1-->6 Man beta sequence were unambiguously determined by two-dimensional proton nuclear magnetic resonance (1H-NMR) spectroscopic methods. The chemical shift of H4 (3.84 ppm) of the beta-Man residue was for the first time revealed to be different from those (approximately 3.77 ppm) of biantennary and alternative type of triantennary glycans having a GlcNAc beta 1-->2 Man alpha 1-->6 Man beta sequence, but quite close to that (3.86 ppm) of a pentaantennary glycan containing a GlcNAc beta 1-->6 residue on the Man alpha 1-->6 Man beta sequence. Thus, the addition of GlcNAc beta 1-->6 residue on the Man-4' residue, whose formation is catalyzed by GlcNAc transferase V, is considered to cause a down-field shift of beta-Man H4 in the complex-type N-glycan chains. One possible explanation of this phenomenon is that the conformation of Man alpha 1-->6 arm is folded back toward the proximal core region, as is the case with the complex-type N-glycan chains with the bisecting GlcNAc residue.

Acetylglucosamine↗

Occurrence of terminal alpha 2-->8-linked disialylated poly-N-acetyllactosamine chains with Le(X) and I antigenic glycotopes in tetraantennary arms of an N-linked glycoprotein isolated from rainbow trout ovarian fluid.

The Pronase digestion of a 54K glycoprotein present in ovarian fluid of rainbow trout yielded a major glycopeptide. Carbohydrate compositional analysis revealed that this glycopeptide was likely to possess a single large N-glycan chain having low molecular weight oligomers of N-acetylneuraminic acid (oligoNeu5Ac). Structural studies of this glycopeptide revealed novel alpha 2-->8-linked disialylated poly-N-acetyllactosamine chains with Le(X) and I antigenic determinants on the N-linked tetraantennary core glycan. In our recent studies (Kitazume,S., Kitajima,K., Inoue,S., Inoue,Y. and Troy,F.A. (1994) J. Biol. Chem. 269, 10330-10340) we presented evidence that synthesis of alpha 2-->8-linked polysialic acid (polySia) chains is a two-step process in which chain initiation is catalyzed by an alpha 2-->8-sialyltransferase (alpha 2-->8-ST; initiase) that catalyzes synthesis of the first Sia alpha 2-->8-linkage, forming the disialic acid (diSia) unit, Sia alpha 2-->8-Sia alpha 2-->6-Gal-. Chain polymerization is then postulated to be catalyzed by a second enzyme, an alpha 2-->8-polyST ("polymerase") that converts the diSia units to polySia chains. The present structural studies leading to the discovery of alpha 2-->8-linked disialylated units that terminate poly-N-acetyllactosamine chains in an N-linked glycoprotein is further evidence in support of our hypothesis that more than one sialyltransferase activity is required for polySia chain synthesis and polymerization.

Animals↗

Plasmapheresis in the treatment of rapidly progressive glomerulonephritis.

The present study was carried out to examine the efficacy of plasma exchange in patients with rapidly progressive glomerulonephritis (RPGN). Seventeen patients with RPGN were treated with plasmapheresis as adjunct to immunosuppressive therapy. Of these, 4 had antiglomerular basement membrane (GBM) antibody-mediated glomerulonephritis (GN), 8 had immune-complex GN (5 SLE, 2 HSP, 1 cryoblobulinemia), 5 had pauci-immune GN (3 peripheral antineutrophil cytoplasmic antibody [P-ANCA], 1 cytoplasmic antineutrophil cytoplasmic antibody [C-ANCA], 1 other). Treatment of 10 of these patients with plasmapheresis within the first month of disease onset resulted in a stable renal function for a period extending from 1 to 3 years, except in 2 patients who had high baseline levels of serum creatinine. In the remaining patients, 2 were treated with hemodialysis 6 years later at the end of follow-up. We conclude that plasmapheresis, when used in combination with immunosuppressive drugs, is beneficial, leading to improved renal function.

Basement Membrane↗

Identification of type VI collagen synthesizing cells in human diabetic glomerulosclerosis using renal biopsy sections.

Although the role of extracellular matrices in the development of glomerulosclerosis has been discussed widely, the cellular origin of type VI collagen in diabetic nephropathy (DN) has remained relatively unexplored. This study reports the distribution and cellular origin of type VI collagen in DN. Type VI collagen-specific oligonucleotide probes and monoclonal antibody were used to assess the relative expression of mRNA for alpha 1 (VI) chain and its translated protein in paraffin-embedded renal biopsy sections of DN. By immunohistochemistry, compared to the control, increased deposition of type VI collagen was noted in the diffuse and nodular lesions of diabetic glomeruli. For cellular localization of type VI collagen mRNA, paraffin-embedded renal sections of the control and DN were hybridized in situ with digoxigenin (Dig)-labeled antisense oligo-DNA probe complementary to a part of alpha 1 (VI) mRNA. In comparison to the control kidney sections, increased numbers of intraglomerular cells (both mesangial and epithelial cells) were positive for alpha 1 (VI) mRNA in renal biopsy sections of DN. From the results, we conclude that overexpression of type VI collagen by intraglomerular cells with its increased deposition might significantly contribute to the glomerulosclerosis found in DN.

Biopsy↗

Clinical application of biochemical modulation in cancer chemotherapy: biochemical modulation for 5-FU.

The addition of Uracil to Tegafur, a prodrug of 5-fluorouracil (5-FU), has been shown to enhance the antineoplastic effect of 5-FU while reducing the side effects attributed to 5-FU catabolism. Studies of 5-FU levels have shown that the 5-FU concentration in the tumor tissues of patients with head and neck cancer was 16.9 times greater than that in serum and approximately 2-6 times greater than in normal tissue. Similar observations have been made in tumor tissues of patients with breast cancer. The clinical efficacy of UFT, the combination of Uracil and Tegafur in a molar ratio of 4:1, has been studied in a variety of tumor types. An overall response rate of about 23% was obtained, with responses exceeding 30% in patients with head and neck, breast, and bladder cancer. Side effects are predominantly that of gastrointestinal toxicity. Hematologic toxicity is minimal and hepatotoxicity is rare. The UFT combination produces a good clinical effect in a variety of tumor types and is well tolerated.

Adolescent↗

Negative charges bound to collagen fibrils in the rabbit articular cartilage: a light and electron microscopic study using cationic colloidal iron.

Negative charged sites in the normal rabbit articular cartilage were investigated using cationic colloidal iron methods. In light microscopy of the cartilage stained with the colloidal iron at pH 1.5, a distinct Prussian blue reaction was observed in the pericellular matrix, and a weak blue reaction in the territorial and interterritorial matrices. At pH 7.0, a diffuse Prussian blue reaction was observed in the pericellular and interterritorial matrices. Digestion with chondroitinase ABC, hyaluronidase and keratanase could not erase the Prussian blue reaction. However, the sections digested with collagenase followed by chondroitinase ABC showed significant elimination of the Prussian blue reaction. Electron microscopy of ultrathin sections stained with the colloidal iron at pH 1.5 revealed that the cationic colloid particles were deposited abundantly in the pericellular matrix and dotted along collagen fibrils in the territorial and interterritorial matrices. The present results suggest that negatively charged sites in the articular cartilage derive mostly from chondroitin sulfate, whose proteoglycans firmly bind to collagen fibrils. Such an ultrastructure may maintain the electrostatic microenvironment in the collagen plexus, holding much water in the cartilage matrix, and also producing biomechanical properties such as tensile strength and elasticity of the cartilage.

Animals↗

Severe chest pain due to gastric anisakiasis.

We treated two cases of gastric anisakiasis presenting with severe chest pain. In both cases, there was a history of prior ingestion of raw saltwater fish. After endoscopic removal of larvae, the chest pain disappeared and never recurred. Other diseases causing chest pain were ruled out by symptoms, signs, blood tests, electrocardiography, chest radiograph, and ultrasonic examination of the heart and abdomen. Thus the chest pain was considered to be caused by gastric anisakiasis. Gastric anisakiasis should be included in the differential diagnosis of acute chest pain.

Adult↗

Myeloperoxidase-antineutrophil cytoplasmic antibody-associated glomerulonephritis with membranous nephropathy in remission.

A 47-year-old woman developed pulmonary hemorrhage and an increase in proteinuria during remission of membranous nephropathy. Renal biopsy revealed crescentic glomerulonephritis. She also had a high perinuclear antineutrophil cytoplasmic antibody level, so a diagnosis of myeloperoxidase-antineutrophil cytoplasmic antibody-associated glomerulonephritis was made. After immunosuppressive therapy was started, the pulmonary hemorrhage resolved and her proteinuria decreased. Renal biopsy was repeated after treatment and showed histological improvement. This case suggests that there may be a relationship between membranous nephropathy and myeloperoxidase-antineutrophil cytoplasmic antibody-associated glomerulonephritis.

Anti-Glomerular Basement Membrane Disease↗

Frequent hepatic involvement in adult T cell leukemia: comparison with non-Hodgkin's lymphoma.

We examined 111 patients with acute type- or lymphoma type-adult T-cell leukemia (ATL) and compared them with 106 patients with non-Hodgkin's lymphoma (NHL). In addition to skin involvement and hypercalcemia which are already known to be frequent in ATL, ATL patients showed an higher incidence of hepatic involvement. There was more frequent palpable hepatomegaly, higher total bilirubin, GOT, GPT, lactate dehydrogenase (LDH), and alkaline phosphatase values in ATL than in NHL patients (p < 0.0001). Among 36 autopsied liver samples, invasion of ATL cells was confirmed in 22 cases. ATL patients with impaired hepatic function showed shorter survival times than patients without hepatic dysfunction. Moreover, ATL patients showed a worse performance status (PS), a higher incidence of lytic bone lesions, lower total protein (TP) and serum albumin levels than NHL patients. This invasive characters of ATL cells and consequent impaired general condition seemed to be factors affecting the poor prognosis recorded in ATL.

Adult↗

[Juvenile cerebral infarction with familial hyperlipoproteinemia (a)--case report].

A 34-year-old male with a history of angina pectoris suddenly developed weakness in the right upper and lower limbs, and consulted our hospital. Computed tomography (CT) and magnetic resonance imaging (MRI) suggested cerebral infarction. Cerebral angiography revealed stenosis at the M1 portion of the left middle cerebral artery. Hypertension, diabetes, tobacco or hyperlipidemia were not considered as risk factors for cerebral infarction. The lipoprotein (a) [Lp(a)] level was high. In the present case, medication with a nicotinic acid agent, niceritrol, for hyperlipoproteinemia and low density lipoprotein (LDL) apheresis were performed. Concerning family history, the patient's mother and younger sister had hyperlipoproteinemia. Recent studies have reported that increased Lp(a) levels are an independent risk factor even in cerebral infarction and coronary artery disease. Measurement of Lp(a) levels and treatment for increased Lp (a) levels may be important.

Adult↗

[Clinical efficacy of GG032X tablets, a new dosage form of ondansetron (fast dispersing tablet), on cisplatin-induced nausea and emesis].

The inhibitory effects of GG032X tablets, a new dosage form (fast dispersing tablet) of ondansetron, 5-HT2 receptor antagonist, on nausea and emesis induced by cisplatin (CDDP), were investigated along with safety and usefulness. Subjects were chemotherapy patients starting CDDP administration for the first time, who were receiving a high single dose of CDDP (50 mg/m2 or more and intravenous drip infusion of less than 4 hours), or lower multiple doses of CDDP (a single dose of 10 mg/m2 or more, administered intravenously for 3-5 consecutive days). GG032X tablets were administered orally 1-2 hours before CDDP administration. In lower multiple doses of CDDP, GG032X tablets and CDDP were administered, as much as possible, at the same respective time when they were administered on the first day. Efficacy of GG032X tablets was evaluated in terms of inhibitory effect on nausea and emesis 24 hours after administration of a high single dose of CDDP, and of the inhibitory effect on nausea and emesis during the study period (3-5 days) in lower multiple doses of CDDP. Efficacy, safety and usefulness were evaluated in accordance with the evaluation criteria used in the clinical study of already-approved ondanstron tablets. In a high single dose of CDDP, the cases judged "effective" or better in the investigation of the inhibitory effect of the drug on nausea and emesis, accounted for 52.9% (63/119 cases). As for the overall safety rating, the cases judged as "safe" accounted for 87.0% (107/123 cases), and as a "minor safety problem" accounted for 13.0% (16/123 cases). As for the usefulness rating, the cases judged "useful" or better accounted for 52.1% (62/119 cases). Major adverse effects included headache, fever, atrial fibrillation and increases in total bilirubin, GOT and GPT values. None of these was serious, and the patients recovered without any treatment or by nosotropic therapy. Meanwhile, in lower multiple doses of CDDP, the inhibitory effect judged "effective" or better accounted for 70.6% (12/17 cases). As for the overall safety rating, all cases were judged "safe". In terms of usefulness, those cases judged "useful" or better accounted for 70.6% (12/17 cases). No adverse effect was observed. Study results of these two groups were almost the same as those for already-approved ondansetron tablets. According to the results of questionnaires for the patients who participated in the study and took GG032X tablets, the drug was found to be easy to take and had favorable results. Based on the above results, GG032X tablets were evaluated as having the same inhibitory effect as the already-approved ondansetron tablets against CDDP-induced nausea and emesis, and were considered safe and clinically useful.

Administration, Oral↗

[TUT-7 phase I clinical study. TUT-7 Study Group].

A phase I study with TUT-7, a new anthracycline antitumor antibiotic, was conducted in 35 malignant tumor patients at 11 institutions nationwide. The study was initiated with a single dose at 100 mg/body which was equivalent to 2n, then the dose as escalated up to 700 mg/body in accordance with the modified Fibonacci's scheme. The dose limiting factor (DLF) was considered to be leukopenia, and maximum tolerated dose (MTD) was 700 mg/ body. The consecutive days dosing study subsequently conducted started with 25 mg/body/day, and the dose level was escalated up to 150 mg /body/day. TUT-7 was orally administered for seven (7) to fourteen (14) consecutive days in principle. It was considered that DLF was leukopenia and MTD was 100 mg/body/day for consecutive days dosing. The study indicated that serum drug concentrations reached their plateaus on the 5th day after initiation of TUT-7 treatment and the accumulation of this compound was low. With these findings, a regimen with a dose of 100 mg/body/day orally administered for 14 consecutive days was recommended for early phase II studies.

Administration, Oral↗

[TUT-7 early phase II clinical study for various solid tumors and hematologic malignancies].

An early Phase II study with TUT-7 (menogaril), a new anthracycline antitumor antibiotic, was conducted in patients with various malignant tumors at 81 departments of 65 institutions nationwide. One course of TUT-7 treatment consisted of seven (7) or fourteen (14) consecutive days of administration at 75 or 100 mg/body/day with two-week drug withdrawal; at least two courses of treatment were given in principle. Among the 165 patients registered, 145 patients were eligible and 128 patients were evaluable for antitumor efficacy. In 11 patients with malignant lymphoma, one (1) had CR and five (5) had PR (54.5%); in three (3) patients with prostate cancer, one (1) had PR (33.3%); and in 12 patients with uterine cervical cancer, two (2) had PR (16.7%). Adverse drug reactions frequently observed were digestive organ disorders (anorexia and nausea/vomiting) and malaise. The abnormality in laboratory tests observed frequently was myelosuppression (leukopenia and neutropenia).

Adult↗

[Menogaril (TUT-7) late phase II study for malignant lymphoma, adult T-cell leukemia and lymphoma (ATLL)].

A late Phase II multicenter study with menogaril was conducted nationwide in patients with malignant lymphoma [non-Hodgkin's lymphoma (NHL), Hodgkin's disease (HD)], and ATLL, menogaril was orally administered at 100 mg daily after breakfast, for seven consecutive days with two- or three-week drug withdrawal, then menogaril administration was repeated. For malignant lymphoma, in 81 patients with NHL and 5 patients with HD registered, 70 and 5 patients were evaluable for efficacy, respectively. The efficacy rates were 32.9% (6 CRs + 17 PRs/70) for NHL and 20.0% (1 PR/5) for HD, respectively; that for the NHL patients with prior anthracycline antibiotic chemotherapy was 30.5% (5 CRs and 13 PRs/59). For ATLL, among the 16 patients registered, 15 were evaluable for efficacy, and the efficacy rate was 40.0% (2 CRs and 4 PRs/15). Adverse drug reactions frequently observed in the patients with malignant lymphoma and ATLL included bone-marrow suppression and gastrointestinal symptoms such as anorexia, and nausea/vomiting. With these results, menogaril was considered to be effective for the treatment of non-Hodgkin's lymphoma and ATLL.

Administration, Oral↗