Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

At least 73 records · Page 4Linked to original sources

PubMed1999

Localization of verotoxin receptors in nervous system.

We use immunohistochemistry to show the existence of verotoxin receptor in small sensory neurons in DRG of human, rabbit, rat and mouse. In capillary in nervous system, the verotoxin receptor exists in human and rabbit, but the receptor could not be demonstrated in rat and mouse, by this method. The receptors in sensory neuron of rat and in capillary in rabbit brain are determined as galactosylglobotriaosylceramide (GalGb3) and globotriaosylceramide (Gb3,), respectively. Although verotoxin was reported to bind to glycolipid receptors that possess the terminal disaccharide Galalpha1-4Galbeta (galactobiose), the binding to toxin to galabiosylceramide was half of that of GalGb3 which has galactobiose internally.

Animals↗

PubMed1999

Trigeminal ganglioneuroma.

We present the case of an 8-year-old girl with a ganglioneuroma in the left cerebellopontine angle region. The tumor originated from the sensory root of the trigeminal nerve. Histopathologically, it was composed of neoplastic ganglion cells and Schwann cells, leading us to the diagnosis of ganglioneuroma. Intracranial ganglioneuroma is very rare. To our knowledge, this is the first report of a trigeminal ganglioneuroma. The nature and origin of this tumor are discussed and the literature reviewed.

Cerebellopontine Angle↗

PubMed1999

Epithelioid trophoblastic tumor: morphological and immunohistochemical study of three lung lesions.

Epithelioid trophoblastic tumor (ETT) is a term proposed for an unusual variant of trophoblastic tumor that is closely related to choriocarcinoma but shows monomorphic growth of highly atypical trophoblastic cells instead of the typical dimorphic pattern of choriocarcinoma. We report here 3 cases of ETT, all of which were lung lesions probably originating from uterine trophoblastic disease. The antecedent pregnancies of the 3 cases were hydatidiform mole, invasive mole, and term pregnancy, respectively. The tumors were composed of highly atypical mononucleate cells, which mainly involved alveolar spaces, forming nests with central eosinophilic necrosis. Multinucleate giant cells were found within the nests, but they were fewer in number than in typical choriocarcinoma. The tumors were not associated with extensive hemorrhage or necrosis, except for 1 case, in which the ETT was combined with typical dimorphic choriocarcinoma. Immunohistochemically, multinucleate giant cells and occasional mononucleate tumor cells showed positivity for human chorionic gonadotropin. Staining for human placental lactogen was positive in rare multinucleate giant cells, and in 1 case, tumor cells showed diffuse positivity for placental alkaline phosphatase. Because ETT has a remarkably epithelioid appearance in cytological and architectural features, differentiation from the epithelial malignancies is problematic. Trophoblastic markers are frequently expressed in nontrophoblastic tumors, and reactivity for those markers alone is not sufficient for exclusion of other tumors. Rather, evidence of ETT comes from a combination of morphological features, immunohistochemical study, and clinical history.

Adult↗

PubMed1999

Differential vascular alpha1-adrenoceptor antagonism by tamsulosin and terazosin.

AIMS: In patients with lower urinary tract symptoms suggestive of benign prostatic obstruction the alpha1-adrenoceptor antagonist terazosin lowers blood pressure whereas only very small if any alterations were reported with the alpha1-adrenoceptor antagonist tamsulosin. Therefore, we have compared the vascular alpha1-adrenoceptor antagonism of tamsulosin and terazosin directly. METHODS: Ten healthy subjects were investigated in a randomized, single-blind, three-way cross-over design and received a single dose of 0.4 mg tamsulosin, 5 mg terazosin or placebo on 3 study days at least 1 week apart. Before and 1, 3, 5, 7, 10 and 23.5 h after drug intake, alterations of diastolic blood pressure and other haemodynamic parameters in response to a graded infusion of the alpha1-adrenoceptor agonist phenylephrine were determined non-invasively. RESULTS: At most time points tamsulosin inhibited phenylephrine-induced diastolic blood pressure elevations significantly less than terazosin (5 h time point: median difference in inhibition 35%, 95% CI: 18.7-50.3%). On the other hand, phenylephrine-induced changes of cardiac output, heart rate and stroke volume were similar during both active treatments. CONCLUSIONS: In doses equi-effective for treatment of lower urinary tract symptoms tamsulosin causes less inhibition of vasoconstriction than terazosin.

Adrenergic alpha-Antagonists↗

PubMed1999

A mammalian ortholog of Drosophila timeless, highly expressed in SCN and retina, forms a complex with mPER1.

BACKGROUND: It is now becoming clear that the circadian rhythm of behaviours and hormones arises from a rhythm at the level of gene expression, and that mammals and Drosophila essentially use homologous genes as molecular gears in the control of circadian oscillation. In Drosophila, the period and timeless genes form a functional unit of the clock and its autoregulatory feedback loop for circadian rhythm. However, in mammals, the counterpart of timeless has not been found. RESULTS: We have isolated a mammalian homologue of timeless, mTim, from the mouse brain. mTim is highly expressed, with a weak or absent rhythm in the suprachiasmatic nucleus, the mammalian circadian centre. In the retina, mTim mRNA was found to be expressed with a circadian rhythm, and a particularly robust cycle was observed in the presence of light/dark cycles. We demonstrated that mTIM physically associates with mPER1 in vitro and in the nuclei of cultured COS7 cells. CONCLUSIONS: We have reported the isolation of the mouse timeless cDNA, the expression of the mTim mRNA and an interaction of mTIM with mPER1. These results indicate that the autoregulatory feedback mechanism of circadian oscillation of the period gene may also be conserved in mammals.

Amino Acid Sequence↗

PubMed1999

Identification of human cytochrome P450 isoforms involved in the metabolism of S-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid.

1. To identify the cytochrome P450 (CYP) isoenzymes responsible for the major metabolic pathways of S-2-[4-(3-methyl-2-thienyl)phenyl] propionic acid (S-MTPPA) in man, the metabolism of S-MTPPA was examined using human liver microsomes and microsomes containing cDNA-expressed CYP isozymes (CYP1A2, 2A6, 2B6, 2C9-Arg, 2C9-Cys, 2C19, 2D6-Val, 2E1 and 3A4). 2. S-MTPPA was mainly oxidized to the 5-hydroxylated metabolite of the thiophene ring (MA6) with human liver microsomes in the presence of NADPH. The formation of MA6 was inhibited by SKF 525-A, suggesting that CYP plays role in the formation of MA6. 3. Eadie-Hofstee plots for the 5-hydroxylation of S-MTPPA in the range 5-100 microM were linear for all samples studied, suggesting that the formation of MA6 by human liver microsomes follows simple Michaelis-Menten kinetics. Apparent Vmax = 1.42+/-0.64 nmol/min/mg protein; Km = 12+/-5 microM. 4. Among the CYP inhibitors examined (alpha-naphthoflavone, sulphaphenazole, omeprazole, quinidine and troleandomycin), sulphaphenazole (a CYP2C9 inhibitor) showed the most potent inhibitory effect on the 5-hydroxylation of S-MTPPA by human liver microsomes. 5. When incubated with microsomes containing cDNA-expressed CYP isozymes, S-MTPPA was substantially oxidized to MA6 only by CYP2C9. 6. These results suggest that formation of the major metabolite of S-MTPPA, MA6, in human liver microsomes is catalysed predominantly by a single CYP isoenzyme, namely CYP2C9.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

Enhancement of propylene glycol distribution in the skin by high purity cis-unsaturated fatty acids with different alkyl chain lengths having different double bond position.

Enhancement of skin distribution of propylene glycol (PG) in the skin by high purity cis-unsaturated fatty acids with different alkyl chain lengths was studied in the rat using Fourier transform/attenuated total reflection (FT-IR/ATR) analysis. Two fatty acids with the double bond at the delta9 position, palmitoleic acid (omega7, delta9) and oleic acid (omega9, delta9), enhanced PG flux into the dermis and increased the dermal steady state level of PG. In contrast, myristoleic acid (omega5, delta9) was extremely weak in its action. A positional effect of the omega chain was observed. The rate of skin structural alteration increased in proportion to omega chain length. The application of three fatty acids with the double bond at the omega9 position, oleic acid (omega9, delta9), gondoic acid (omega9, delta11), erucic acid (omega9, delta13) enhanced PG distribution in the skin. While, nervonic acid (omega9, delta15) did not increase PG distribution in the skin. The relationship of the delta/omega ratio to parameters characterizing the action of enhancers (PG(peak area max), T(max alteration), and the slope) suggest that skin distribution increases as the position of the double bond is shifted toward the hydrophilic end. It is therefore likely that the ratio of the delta/omega chain length of the cis-unsaturated fatty acid determines the efficacy of these compounds as skin penetration enhancers. An adequate molecular volume may be required for cis-unsaturated fatty acids to act as enhancers.

Animals↗

PubMed1999

Morphological study on pigmented cells in the horse testis.

One of the most attractive characteristics of a horse testis is the change of the weight during development. As the testicular weight changes and the number of Leydig cells decreases, pigments appear in interstitial tissues. In the present study, the characteristics of the pigments found in the interstitial tissues were examined histochemically and ultrastructurally. Specific stainings indicated that the pigmented granules showed almost all of the histological and histochemical characteristics of ceroid or ceroid-like pigment. The cells showed positive reaction for acid phosphatase while the pigmented cells contained a lot of lysosomes ultrastructurally. These results suggest that macrophages might phagocytize Leydig cells, and store their digested materials as ceroid-like pigment.

Animals↗

PubMed1999

Anatomical studies of the autonomic nervous system in the human pelvis by the whole-mount staining method: left-right communicating nerves between bilateral pelvic plexuses.

PURPOSE: Some recent neurophysiological studies have suggested cross-innervation of pelvic genitourinary organs by extrinsic left-right communicating nerves. However, no definite course for these nerves has been clearly determined macroanatomically in humans. In the present study we extensively investigated the adult human pelvis to elucidate their courses by the whole-mount staining method. MATERIALS AND METHODS: A total of 6 male human specimens that had been subjected to pathological dissection were examined by means of an acetylcholinesterase whole-mount staining method. A map of nerve pathways was made by composite photomicrography. Histologically, nerves dissected accurately under a dissecting microscope were stained with both Klüver-Barrera stain and the Bodian method. RESULTS: The communicating nerves between bilateral pelvic plexuses were observed at the back of the rectum and in the rectoprostatic space. The former were composed of nothing but myelinated fibers in the same way as the pelvic splanchnic nerve. By contrast, the latter were composed of unmyelinated fibers with a few myelinated fibers. The pelvic plexus could be divided into three portions, anterosuperior, anteroposterior and inferior areas, by ganglion type. Morphologically, fiber components differed among those three portions. CONCLUSION: The communicating nerves at the back of the rectum seemed to be predominantly parasympathetic communicantes between bilateral pelvic splanchnic nerves rather than pelvic plexuses. These nerves may be involved in postoperative voiding function in the case of pelvic surgery with hemilateral nerve preservation. The function of the pelvic plexus seemed to be heterogeneous in each portion according to our morphological results.

Aged↗

PubMed1999

The effects of morphine-induced increases in extracellular acetylcholine levels in the rostral ventrolateral medulla of rat.

The present study examined the role of the rostral ventrolateral medulla (RVLM) in the modulation of acetylcholine (ACh) release by morphine. We examined the effect of morphine on the release of ACh in the RVLM of freely moving rats using the in vivo microdialysis method. The basal level of ACh was 303.0 +/- 28.2 fmol/20 microliter/15 min in the presence of neostigmine (10 microM). Morphine at a low dose of 5 mg/kg (i.p.) increased ACh release by the RVLM by 42.4%. A higher morphine dose (10 mg/kg i.p.) significantly increased the release of ACh by 75.4%, with a maximal effect (86.4%) at 75 min. This enhancement following i.p. administration of morphine was reversed by naloxone (1 mg/kg i.p.). Addition of morphine (10(-4) M) to the perfusion medium increased the ACh release by 85.8% of the predrug values. The increased ACh release induced by local application of morphine was reversed by pretreatment with naloxone (1 mg/kg i.p.). The antinociceptive effect of locally applied morphine into the RVLM was assessed using the hot-plate test and tail immersion test in unanesthetized rats. Local application of morphine (10(-4) M) via a microdialysis probe induced an increase in both tail withdrawal and hot-plate response. These findings suggest that morphine seems to exert a direct stimulatory effect on ACh release by the RVLM and that morphine-induced nociception is, in part, activated by the release of ACh in freely moving rats.

Acetylcholine↗

PubMed1998

Clinicopathologic features of patients with hepatocellular carcinoma surviving >10 years after hepatic resection.

BACKGROUND: This study was performed to clarify the clinicopathologic features of hepatocellular carcinoma (HCC) patients surviving >10 years after hepatic resection. METHODS: Between January 1971 and April 1987, 142 patients underwent hepatic resection. Thirty-nine patients who died of surgical morbidity (surgical mortality rate: 27.5%) were excluded from this study. Among the 103 patients who survived and were observed for >10 years after surgery, 12 patients (11.7%) survived >10 years after hepatectomy. The surviving patients were divided into 2 groups: 10-year survivors (n = 12) and nonsurvivors (n = 91). A comparative study between the two groups was made. RESULTS: Preoperative liver function tests such as the indocyanine green retention test at 15 minutes and albumin levels showed that 10-year survivors had better liver function than nonsurvivors. With regard to virus markers, 5 of 12 patients (41.7%) were positive for hepatitis B surface antigen (HBs-Ag) and the incidence of hepatitis B virus-related HCC was significantly higher than in nonsurvivors (P = 0.020). The results also showed that 4 of 12 long term survivors had hepatitis C virus (HCV) antibody and 1 patient did not have any HCV antibody or HBs-Ag. In two other patients, the HCV antibody was not measured and HBs-Ag was negative. Among four patients with the HCV antibody, the serum HCV RNA concentration, measured by branched DNA probe assay, was <0.5 in 3 patients and 1.72 in 1 patient. Therefore, the HCV RNA concentration tended to be lower in 10-year survivors. Tumor recurrence occurred in 8 of the 10-year survivors. Solitary recurrence was observed in five patients whereas multiple recurrence was observed in three patients. All five patients with solitary recurrence underwent a second resection. CONCLUSIONS: Based on the results of the current study, good liver function, HBs-Ag positivity, and a low concentration of serum HCV RNA in HCV-related HCC should be considered potentially good predictors of a long term survival.

Adult↗

PubMed1998

The effect of methamphetamine on the release of acetylcholine in the rat striatum.

We examined the effect of methamphetamine on the release of acetylcholine in the striatum of freely moving rats, using an in vivo microdialysis method. The basal level of acetylcholine was 3.67+/-0.47 pmol/30 microl per 15 min in the presence of neostigmine (10 microM). Tetrodotoxin (1 microM), a selective blocker of voltage-dependent Na+ channels, markedly inhibited the release of acetylcholine in the striatal perfusates. Apomorphine (1.0 mg/kg, i.p.), a dopamine receptor agonist, also significantly attenuated acetylcholine release. Methamphetamine (0.1 and 0.5 mg/kg, i.p.) did not immediately affect acetylcholine release in the striatum, but a dose of 1.0 mg/kg (i.p.) induced an increase of acetylcholine release in the striatum at 15-60 min. Striatal infusion of methamphetamine (5 and 10 microM) did not influence acetylcholine release. The increase following intraperitoneal administration of methamphetamine was slightly diminished by haloperidol (0.5 mg/kg). After microinjection of the neurotoxin, 6-hydroxydopamine (6 microg/3 microl), in the substantia nigra 7 days before, the increase of acetylcholine induced by the administration of methamphetamine (1.0 mg/kg) was slightly attenuated, whereas the administration of reserpine (2 mg/kg, i.p.) 24 h before, combined with alpha-methyl-p-tyrosine (300 mg/kg, i.p.) 2.5 h before, completely blocked the increase in release of acetylcholine. These findings suggest that methamphetamine exerts an excitatory influence on striatal acetylcholine release in freely moving rats, and that this excitatory effect involves the dopaminergic system and the catecholaminergic system.

Acetylcholine↗

PubMed1998

A light-independent oscillatory gene mPer3 in mouse SCN and OVLT.

A new member of the mammalian period gene family, mPer3, was isolated and its expression pattern characterized in the mouse brain. Like mPer1, mPer2 and Drosophila period, mPer3 has a dimerization PAS domain and a cytoplasmic localization domain. mPer3 transcripts showed a clear circadian rhythm in the suprachiasmatic nucleus (SCN). Expression of mPer3 was not induced by exposure to light at any phase of the clock, distinguishing this gene from mPer1 and mPer2. Cycling expression of mPer3 was also found outside the SCN in the organum vasculosum lamina terminalis (OVLT), a potentially key region regulating rhythmic gonadotropin production and pyrogen-induced febrile phenomena. Thus, mPer3 may contribute to pacemaker functions both inside and outside the SCN.

Amino Acid Sequence↗

PubMed1998

Treatment strategy for patients with cystic lesions mimicking a liver tumor: a recent 10-year surgical experience in Japan.

OBJECTIVE: To clarify some of the difficulties in determining the appropriate surgical indications for cystic lesions mimicking a neoplasm in the liver. DESIGN: A retrospective review of hepatic resections for cystic lesions mimicking a neoplasm in the liver between August 1, 1986, and July 31, 1996. SETTING: A university hospital with a long history of hepatic resection for cystic lesions mimicking a neoplasm in the liver. PATIENTS: Ten patients with such cystic lesions in the liver, who underwent a hepatectomy during a recent 10-year period, were included in this study. MAIN OUTCOME MEASURES: Detailed clinicopathologic data were analyzed, and comparisons were made between the preoperative and postoperative diagnoses. RESULTS: The postoperative diagnoses consisted of cysts, including cysts complicated by an infection or hemorrhage in 7 patients, localized cystic dilation of the bile duct due to hepatolithiasis in 1, cystadenoma in 1, and mucin-producing cholangiocarcinoma in 1. In only one case was postoperative diagnosis identical to the preoperative diagnosis. In one case, an intraoperative pathological examination showed the tumor to be a mucin-producing cholangiocarcinoma instead of a cystadenocarcinoma. A tumor-marker analysis of the fluid in the cystic lesions also did not contribute to a definite diagnosis. Furthermore, cytological examination of the fluid could not completely exclude malignancy. Neither mortality nor morbidity occurred in any of the patients, and their mean length of hospitalization after hepatectomy was only 13.7 days. CONCLUSIONS: The accurate diagnosis of cystic lesions mimicking a tumor remains problematic; however, the results of hepatectomy for such cases are normally satisfactory. Such cystic lesions of the liver should be indicated for hepatectomy whenever the possibility of a cancerous neoplasm cannot be completely ruled out.

Adult↗

PubMed1998

Bone marrow necrosis in a patient with acute myeloblastic leukemia during administration of G-CSF and rapid hematologic recovery after allotransplantation of peripheral blood stem cells.

Allogeneic peripheral blood stem cell transplantation from an HLA-identical sibling was performed for a 38-year-old male with refractory acute myeloblastic leukemia. The patient was conditioned with total body irradiation (TBI) and high-dose cytosine arabinoside (Ara-C). G-CSF (300 microg/body) was started for priming of residual leukemic cells 24 hr before the beginning of TBI (day -9). However, intolerable generalized bone pain appeared shortly after the start of first dose of G-CSF, and persisted for 3 days in spite of the cessation of G-CSF. Posttransplant hematopoietic engraftment was very rapid. Bone marrow biopsy specimens on day 14 and 30 showed typical bone marrow necrosis histologically. This is the first case of bone marrow necrosis during administration of G-CSF, and our experience suggests that PBSC could repopulate hematopoiesis in spite of severe bone marrow necrosis.

Adult↗

PubMed1998

Enhanced expression of thrombospondin-1 and hypovascularity in human cholangiocarcinoma.

Cholangiocarcinoma (CCC) is relatively hypovascular, in contrast to hepatocellular carcinoma (HCC), which is often highly vascular. We investigated if the diminished vascularity of CCC is related to altered expression of thrombospondin-1 (TSP-1), an antiangiogenic factor, and/or vascular endothelial growth factor (VEGF), a potent angiogenic factor, comparing the relationships with those of high- and low-vascular HCC. We also investigated the relationship between the mutation of the p53 gene and TSP-1 expression or VEGF expression. Northern blot analysis and immunohistochemical staining were performed on surgically resected human CCC and HCC. The ratios of TSP-1 mRNA level in cancer cells versus adjacent noncancerous cells (T/N ratios) were significantly higher in CCC (n = 11) than in HCC with high vascularity (n = 15). In contrast, T/N ratios of VEGF mRNA level in CCC (n = 11) were comparable with those in HCC with low vascularity (n = 5). In CCC, the cancer cells and fibroblasts were positively stained with anti-TSP-1 antibody. We observed that T/N ratios of VEGF mRNA level, but not those of the TSP-1 mRNA level, were significantly correlated with vascularity in HCC. The relative increase in TSP-1 and the relative decrease in VEGF in tumors compared with normal tissue may underlie the limited angiogenesis of CCC. The p53 gene did not affect the expression of TSP-1 in CCC or VEGF in HCC.

Adult↗

PubMed1998

Comparison of human alpha1-adrenoceptor subtype coupling to protein kinase C activation and related signalling pathways.

The coupling of human alpha1-adrenoceptor subtypes to protein kinase C (PKC) and PKC-related signalling events were investigated in rat-1 fibroblasts stably expressing alpha1A-, alpha1B- or alpha1D-adrenoceptors at densities of 1328+/-200, 5030+/-703 and 150+/-14 fmol/mg protein respectively. In functional assays the alpha1-adrenoceptor agonist phenylephrine significantly stimulated PKC (assessed as increased activity in the membrane fraction) in cells expressing alpha1A- or alpha1B- but not alpha1D-adrenoceptors. In immunoblot assays phorbol ester treatment enhanced membrane-associated immunoreactivity of PKCalpha, PKCdelta and PKCepsilon to a similar extent in all three cell lines. Stimulation of alpha1A- and alpha1B-adrenoceptors also increased immunoreactivity of PKCalpha, PKCdelta and PKCepsilon in the membrane fraction, while alpha1D-adrenoceptor stimulation yielded only very small and inconsistent alterations. Immunoreactivity of PKCzeta was not consistently affected by phorbol ester or phenylephrine in any of the cell lines. Stimulation of all three alpha1-adrenoceptors time- and concentration-dependently increased inositol phosphate formation. Maximum activation occurred with the order alpha1A approximately = alpha1B > alpha1D. Phenylephrine also concentration dependently elevated free intracellular [Ca2+] in all three cell lines with the order of efficacy alpha1A > alpha1B > alpha1D. In the presence of ethanol, phenylephrine stimulated phosphatidylethanol formation in alpha1A- and alpha1B-adrenoceptor-expressing cells time and concentration dependently but only weakly and inconsistently in alpha1D-adrenoceptor-expressing cells. The efficacy of phenylephrine (100 microM) relative to that of noradrenaline (100 microM) for stimulation of phosphatidylethanol formation was similar (> or = 75%) for all three subtypes. The alkylating agent phenoxybenzamine concentration dependently reduced alpha1A-adrenoceptor density and phenylephrine-stimulated Ca2+ elevations to levels seen with alpha1D-adrenoceptors but reductions of phenylephrine-stimulated phosphatidylethanol formation were weaker. We conclude that human alpha1A- and alpha1B-adrenoceptors expressed in rat-1 cells couple to activation of PKCalpha, PKCdelta and PKCepsilon but not PKCzeta; this may involve stimulation of phospholipases C and D and intracellular Ca2+ elevations. Activation of these pathways by alpha1D-adrenoceptors appears to be much weaker and was not detected consistently; this was not fully explained by weak partial agonism of phenylephrine at this subtype or by lower receptor densities. Overall the alpha1A-adrenoceptor may have the highest efficiency of stimulus-response coupling among human alpha1-adrenoceptor subtypes.

Adrenergic alpha-1 Receptor Antagonists↗

PubMed1998

Transverse colonic stenosis.

A 3-year child presented with episodic lower abdominal pain; during the eighth attack, a mass was palpable in the left upper quadrant, and a barium enema revealed a stenotic area in the transverse colon. This was resected and an uneventful postoperative course followed. Subsequently, the child has remained symptom-free. instruments are no longer in use.

Colon↗