Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

At least 55 records · Page 3Linked to original sources

PubMed2000

The effects of intense click sounds on velocity storage in optokinetic after-nystagmus.

Vestibular evoked myogenic potentials (VEMP) occurring after click stimulation in cervical muscles are thought to be a polysynaptic response of otolith-vestibular nerve origin. In optokinetic after-nystagmus (OKAN) the direction of after-nystagmus changes and slow-phase velocity decreases with head tilt. This phenomenon may be an otolith response to the direction of gravity. We assumed that intense clicks might have some influence on OKAN via the otolith-vestibular nerve. Twelve normal subjects who showed VEMP at 75 dB normal hearing level (nHL) clicks were examined. The OKAN was recorded under four conditions: right monaural, left monaural and binaural stimulation by 75 dB nHL clicks, and absence of click stimulation. Horizontal optokinetic stimulation was applied using stepwise increasing speeds from 30 deg/s to 90 deg/s. Two seconds before the stimulus ended, clicks were sounded. The slow-phase velocity of the recorded electro-nystagmography was manually measured. There was no effect on OKAN with unilateral stimulation but binaural stimulation suppressed it. These results suggest that a velocity storage integrator is influenced by intense clicks via the otolithic area.

Acoustic Stimulation↗

PubMed2000

Recent developments in imaging diagnostics for HCC: CT arteriography and CT arterioportography evaluation of vascular changes in premalignant and malignant hepatic nodules.

We analyzed the hemodynamic properties and vascular supply changes in relation to the carcinogenesis of hepatocellular carcinoma (HCC), selecting 18 premalignant and malignant nodules less than 3 cm diameter (from 14 patients) for our study. The computed tomographic (CT) arteriography and CT arterioportography (CTAP) findings for these nodules were correlated with the histopathologic findings. The ratios of all microscopically counted arteries (normal hepatic and abnormal arteries), normal hepatic arteries, and portal veins in each nodule to those in the surrounding liver were calculated. Well differentiated lesions had low attenuation on CT arteriography and isoattenuation on CTAP. Moderately-to-poorly differentiated lesions had high attenuation on CT arteriography and low attenuation on CTAP. In well differentiated lesions, the ratios of all arteries, normal hepatic arteries, and portal veins were 1.17+/-0.10, 0.66+/-0.12, and 0.80+/-0.10, respectively. In moderately-to-poorly differentiated lesions, the ratios were 2.64+/-0.23, 0.09+/-0.03, and 0.07+/-0.03, respectively. We concluded that blood flow does not parallel the actual number of arteries seen on the histological examination of tumors. In well differentiated lesions, the combination of normal hepatic arterial degeneration and preserved portal veins results in low attenuation on CT arteriography and isoattenuation on CTAP. In advanced HCC, the combination of neoplastic (abnormal) arterial development by angiogenesis and obliteration of portal veins results in high attenuation on CTA and low attenuation on CTAP. These findings are characteristic of early and advanced stage HCC, and may reflect a combination of sequential changes in their hemodynamic states.

Aged↗

PubMed2000

Hepatic sclerosing hemangioma mimicking a metastatic liver tumor: report of a case.

We present herein the case of a sclerosing hemangioma of the liver which was extremely difficult to differentiate from liver metastasis of rectal cancer, in a 67-year-old woman. All the radiological findings were compatible with liver metastasis; however, marginal pooling of the tumor revealed by computed tomographic angiography and magnetic resonance imaging scans was inconsistent with a diagnosis of liver metastasis. At laparotomy, the tumor was macroscopically unusual in that it was yellowish elastic-hard with a very clear margin, and thus, it did not have the appearance of a metastatic tumor. Mile's operation and a partial hepatectomy were performed, followed by an uneventful postoperative course and no signs of recurrence. The carcinoembryonic antigen (CEA) level in the peripheral blood was not elevated at any time. The postoperative pathological diagnosis was a rare hepatic tumor, namely, a "sclerosing hemangioma," based on the findings of cellular fibrous stroma containing vascular channels with flattened endothelial cells. Preoperatively differentiating between sclerosing hemangioma and a metastatic liver tumor from colorectal cancer may be very difficult; however, this case demonstrated some interesting characteristics, namely, the serum CEA level was not elevated, marginal pooling of the tumor was found in the enhanced radiological findings, and the tumor was macroscopically unusual. Therefore, the possibility of sclerosing hemangioma should be borne in mind when considering the differential diagnosis of patients suspected of having colorectal liver metastasis. A preoperative biopsy should be carried out and when a laparotomy is performed under the misdiagnosis of colorectal liver metastasis, it is advisable that either an intraoperative needle biopsy or a frozen histological analysis be undertaken to avoid unnecessary extended hepatic resection of this rare benign hepatic tumor.

Aged↗

PubMed2000

Distribution of capsaicin-sensitive substance P- and calcitonin gene-related peptide-immunoreactive nerves in bovine respiratory tract.

The distribution of nerve fibers immunoreactive for substance P (SP) and calcitonin gene-related peptide (CGRP) was examined by means of immunohistochemical methods in the respiratory tract from nose to lung of normal and capsaicin-treated cattle. SP- and CGRP-immunoreactive (IR) nerve fibers with varicosities were detected in all portions. They were more numerous in calves than in cows. They were abundant in the nasal and laryngeal mucosae and tracheal bronchus, and few in number in the lung. SP- and CGRP-IR nerve fibers were mainly seen in the epithelium, in connective tissue beneath the epithelium and around blood vessels, and in the glands throughout the respiratory tract. In contrast, SP- and CGRP-IR nerve fibers were sparse in the smooth muscle layer. Capsaicin treatment of neonates caused a remarkable reduction in the number of SP- and CGRP-IR nerve fibers in the respiratory tract of calves. Double immunofluorescence experiments showed the colocalization of SP and CGRP in most of the nerve fibers. The present findings suggest that SP- and CGRP-IR nerve fibers are involved in the regulation of the bovine respiratory tract, and that capsaicin-sensitive SP- and CGRP-IR nerve fibers are sensory neurons of the bovine respiratory tract.

Aging↗

PubMed2000

The importance of hepatic resection for hepatocellular carcinoma originating from nonfibrotic liver.

BACKGROUND: Our study aimed to clarify the characteristics of hepatocellular carcinoma (HCC) in patients with a nonfibrotic liver and the role of surgical resection for HCC in nonfibrotic liver compared with patients with HCC in fibrotic or cirrhotic livers. STUDY DESIGN: A total of 516 patients who underwent hepatectomy between April 1985 and June 1999 were classified into two groups: a nonfibrotic liver group (n=65) and a fibrotic liver group (n=451), which included fibrotic or cirrhotic livers. Clinicopathologic variables were then compared between the groups, including disease-free survival rate and patient survival rate. RESULTS: Only 8 of 65 patients (12.3%) with a nonfibrotic liver showed a histologically completely normal liver. The numbers of men and patients with alcohol abuse in the nonfibrotic liver group were higher than in the fibrotic liver group. The numbers of patients with positive hepatitis B antigen and positive hepatitis C antibody in the nonfibrotic liver group were lower than in the fibrotic liver group. Results of liver function tests in the nonfibrotic liver group were better than those in the fibrotic liver group. The rates of both portal vein and hepatic vein invasion of cancer cells in the nonfibrotic liver group were higher than in the fibrotic liver group. The tumor size in the nonfibrotic liver group was larger than in the fibrotic liver group. The patient survival and disease-free survival rates in the nonfibrotic liver group were better than in the fibrotic liver group. CONCLUSIONS: Hepatic resection can be beneficial for patients with HCC originating from a nonfibrotic liver when compared with fibrotic or cirrhotic patients with HCC.

Carcinoma, Hepatocellular↗

PubMed2000

Thrombopoietic activity of recombinant human interleukin-11 in nonhuman primates with ACNU-induced thrombocytopenia.

The effect of recombinant human interleukin-11 (rHuIL-11) on myelosuppressive nimustine (ACNU)-induced thrombocytopenia was assessed in nonhuman primates. A single intravenous (i.v.) injection of ACNU (15 mg/kg) was administered to cynomolgus monkeys on day 0. rHuIL-11 (100 microg/kg/day) or the vehicle was given subcutaneously (s.c.) from day 1 to day 21. In monkeys receiving ACNU, the circulating platelet count decreased to a low of 42 +/- 6 x 10(9)/L by day 21 but returned to pretreatment levels (375 +/- 48 x 10(9)/L) on day 30. Administration of rHuIL-11 prevented severe thrombocytopenia; the platelet count fell only to 138 +/- 23 x 10(9)/L on day 18, and platelet recovery was faster (458 +/- 91 x 10(9)/L by day 27) compared with that of the control animals. The size of bone marrow megakaryocytes from rHuIL-11-treated animals was larger than that of the controls, indicating that rHuIL-11 stimulated megakaryopoiesis in a myelosuppressive condition. Treatment with ACNU also caused leukopenia and moderate anemia. rHuIL-11 transiently and slightly decreased the white blood cell (WBC) and red blood cell (RBC) counts. Conversely, rHuIL-11 accelerated recovery of RBC count in the late administration period. These results support the assertion that rHuIL-11 may be an important therapeutic agent for reducing the severity and duration of thrombocytopenia following cancer chemotherapy.

Animals↗

PubMed2000

High temporal resolution for multislice helical computed tomography.

Multislice helical computed tomography (CT) substantially reduces scanning time. However, the temporal resolution of individual images is still insufficient for imaging rapidly moving organs such as the heart and adjacent pulmonary vessels. It may, in some cases, be worse than with current single-slice helical CT. The purpose of this study is to describe a novel image reconstruction algorithm to improve temporal resolution in multislice helical CT, and to evaluate its performance against existing algorithms. The proposed image reconstruction algorithm uses helical interpolation followed by data weighting based on the acquisition time. The temporal resolution, the longitudinal (z-axis) spatial resolution, the image noise, and the in-plane image artifacts created by a moving phantom were compared with those from the basic multislice helical reconstruction (helical filter interpolation, HFI) algorithm and the basic single-slice helical reconstruction algorithm (180 degrees linear interpolation, 180LI) using computer simulations. Computer simulation results were verified with CT examinations of the heart and lung vasculature using a 0.5 second multislice scanner. The temporal resolution of HFI algorithm varies from 0.28 and 0.86 s, depending on helical pitch. The proposed method improves the resolution to a constant value of 0.29 s, independent of pitch, allowing moving objects to be imaged with reduced blurring or motion artifacts. The spatial (z) resolution was slightly worse than with the HFI algorithm; the image noise was worse than with the HFI algorithm but was comparable to axial (step-and-shoot) CT. The proposed method provided sharp images of the moving objects, portraying the anatomy accurately. The proposed algorithm for multislice helical CT allowed us to obtain CT images with high temporal resolution. It may improve the image quality of clinical cardiac, lung, and vascular CT imaging.

Algorithms↗

PubMed2000

Protein kinase C modulates Ca2+-activated K+ channels in cultured rat mesenteric artery smooth muscle cells.

The electrical and pharmacological properties of protein kinase C (PKC) and its effect on the single Ca2+-activated K+ channel (Kca-channel) in the cultured smooth muscle cells of rat mesenteric artery were studied using a patch-clamp technique. The Kca-channel had a slope conductance of 151+/-7 pS (mean+/-S.E.) in symmetrical 142 mm K solutions. The high conductance K+ channel, applied to the outer side of membrane patches, was potently inhibited by charybdotoxin (0.1 microM) and tetraethylammonium (0.5 microM), but not by apamin (0.4 microM). In cell-attached patches, bath application of phorbol 12-myristate 13-acetate (PMA, 2 microM), a PKC activator, inhibited the activity of the Kca-channel in the presence of the Ca2+ ionophore, A 23187 (10 microM). This inhibition was reversed by subsequent application of staurosporine (1 nM), a PKC inhibitor. Application of 1-oleoyl-2-acetylglycerol (OAG, 30 microM), another PKC activator, also inhibited the A 23187-induced activation of the K+ channel, and this inhibition was reversed by staurosporine. In inside-out patches, bath application of PKC (0.2 munits), in the presence of ATP (1 mM) and PMA (1 microM), inhibited the K+ channel. These results indicate that protein kinase C inhibits the Ca2+-activated K+ channel of mesenteric artery smooth muscle cells in the rat.

Adenosine Triphosphate↗

PubMed2000

Use of electroporation to accelerate the skin permeability enhancing action of oleic acid.

Rat skin permeability after treatment by electroporation (newly developed frog type electrode, 100V, 10 pulses), oleic acid/propylene glycol (PG) and a combination of both were investigated using Fourier transformed infrared attenuated total reflectance (FT-IR/ATR) analysis. Electroporation immediately disordered the stratum corneum lipid structure up to a certain threshold level. This action lasted throughout the experiment. This may be attributed to the formation of long lifetime of metastable lipid structures, which may allow molecules to pass to the inside of the stratum corneum due to the electroporation-induced fluidized lipid membranes. Electroporation also altered the protein structure of the stratum corneum. When electroporation was combined with 0.05 M oleic acid/PG, uptake of oleic acid and PG into the stratum corneum was remarkably accelerated compared to the application of only 0.05 M oleic acid/PG to the skin. This indicates that electroporation enables oleic acid and PG to penetrate the stratum corneum easily by disrupting the structure of the latter. PG transfer into the dermis from the epidermis was accelerated, not because of the direct action of electroporation on the dermis, but because electroporation induced the rapidly disordering action of oleic acid on the stratum corneum. Lipid-soluble indomethacin permeated the skin more rapidly when the skin was treated with electroporation plus oleic acid/PG than with 0.05 M oleic acid/PG in vitro.

Animals↗

PubMed2000

[A very elderly autopsy case of cecal cancer with pulmonary lymphangitis carcinomatosa].

A 91-year-old man was admitted with colliquative diarrhea, anorexia and weight loss. He had a history of healed tuberculosis, hypertension and atherosclerotic abdominal aortic aneurysms. On admission, shortness of breath without cough, exertional dyspnea, and ascites were also noticed. His chest X-ray and CT showed almost normal findings in the lung fields except for calcified old pleurisy. Since laboratory tests revealed thrombocytopenia, low fibrinogen, and increased CA19-9. DIC induced by an unknown cancer was diagnosed. He died on the eighth day due to progressive respiratory failure which did not respond to oxygen therapy. Autopsy revealed that he had a poorly differentiated adenocarcinoma in the cecum complicated with pulmonary lymphangitis carcinomatosa. Lymphangitis should be considered in the case of unexplained progressive respiratory failure developing in patient with cancer, even in the absence of X-ray findings.

Adenocarcinoma↗

PubMed2000

Correlation between elevated intratumoral thymidine phosphorylase and prognosis of node-positive breast carcinoma undergoing adjuvant doxifluridine treatment.

We determined intratumoral thymidine phosphorylase (dThdPase) activity in 213 patients with T2N0M0 or T2N1M0 breast cancer. After surgery doxifluridine, an intermediate metabolite of capecitabine, and tamoxifen were given by mouth. According to dThdPase activity the examined patients were classified as: A, high activity group; tumors with the activity not less than the mean value and B, low activity group; tumors with activity less than the mean value. Group A had a better prognosis than group B in node-positive patients (disease-free survival, p=0.0446; overall survival, p=0.0788). Intratumoral dThdPase activity might be a useful marker for predicting responsiveness to doxifluridine treatment in the adjuvant setting.

Adult↗

PubMed2000

Increased expression of an ATP-binding cassette superfamily transporter, multidrug resistance protein 2, in human colorectal carcinomas.

The expression of ATP-binding cassette superfamily transporter genes, such as P-glycoprotein/multidrug resistance (MDR) 1 and MDR protein (MRP) 1, is often up-regulated in various tumor types and is involved in responses to some anticancer chemotherapeutic agents. Five human MRP subfamily members (MRP2-6) with structural similarities to MRP1 have been identified. The relationships between MRP2-6 mRNA levels and drug resistance are not well understood. Data on 45 patients with colorectal cancer were analyzed. Of the ATP-binding cassette superfamily genes, we asked whether mRNA levels of MDR1, MRP1, MRP2, and MRP3 correlated with drug resistance to anticancer agents. For this analysis, we used quantitative reverse transcription-PCR, and the sensitivity to anticancer agents in surgically resected colon carcinomas was determined using the in vitro succinate dehydrogenase inhibition test. MDR1, MRP1, and MRP3 were highly expressed in normal colorectal mucosa, and the relative mRNA levels of MDR1, MRP1, and MRP3 in cancerous tissues compared with noncancerous tissues were decreased or unchanged. By contrast, MRP2 mRNA expression was low in normal colorectal mucosa and specifically increased in cancer regions compared with noncancerous regions. Of the anticancer agents prescribed for patients with colorectal cancers, including doxorubicin, mitomycin C, cisplatin, 5-fluorouracil, etoposide, and a camptothecin derivative, mRNA expression of MRP2 was significantly associated with resistance to cisplatin. MRP2 may be important for resistance to cisplatin treatment in colorectal cancer.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2000

Effects of microiontophoretically-applied opioid peptides on Purkinje cells in the cat cerebellum.

AIM: The purpose of the present study was to examine the effects of microiontophoretically-applied opioid peptides on Purkinje cell of the cerebellum. METHODS: The effects of microiontophoretically-applied morphine, leucine-enkephalin (Leu-Enk), methionine-enkephalin (Met-Enk), and dynorphin 1-13 (Dyn) on the spontaneous discharge of Purkinje cells in the cerebellum of the anesthetized cat were examined. RESULTS: Microiontophoretic applications of Leu-Enk and morphine produced inhibitory and excitatory responses, respectively in Purkinje cells. Application of both morphine and Leu-Enk induced dose-dependent responses. The excitatory responses were antagonized by naloxone, whereas the inhibitory responses were not. Bicuculline, a GABA-A antagonist, completely abolished both the Leu-Enk- and morphine-induced-inhibitory responses. Iontophoretic application of Met-Enk and dyn produced inhibitory responses only. Met-enk- and dyn-induced inhibition was antagonized by naloxone. CONCLUSION: In Purkinje cell activity, microiontophoretically applied Leu-Enk- and morphine-induced excitation is connected with opiate receptors, whereas inhibition is related to the GABA receptor. However, Met-Enk and dyn produced only inhibitory effects via an opiate receptor in the cerebellum of cats.

Action Potentials↗

PubMed1999

Imaging assessment of the responses of osteosarcoma patients to preoperative chemotherapy: angiography compared with thallium-201 scintigraphy.

BACKGROUND: Assessment of the responses of osteosarcoma patients to preoperative chemotherapy is of clinical importance. The purpose of this study was to estimate the accuracy of angiography and thallium-201 scintigraphy, compared with histology, in assessing the responses of patients with osteosarcoma to preoperative chemotherapy. METHODS: Nineteen patients with osteosarcoma who were diagnosed between 1992 and 1997 were studied. The findings of angiography and thallium-201 scintigraphy before and after preoperative chemotherapy were compared with the percentage of necrosis of tumor cells and the response grade as determined histologically. Quantitative analysis of the isotopic uptake by thallium-201 scintigraphy before and after chemotherapy, defined as the alteration ratio, was correlated with the percentage of tumor necrosis. RESULTS: Angiography yielded a sensitivity of 88%, a specificity of 73%, and a predictive accuracy of positive test of 70%, whereas thallium-201 scintigraphy achieved 88%, 100%, and 100%, respectively. Both angiographic and scintigraphic assessment showed a significant correlation with response grade as determined histologically (P < 0.05 and P < 0.0003, respectively). The alteration ratio of thallium-201 scintigraphy showed a strong, highly significant correlation with the percentage of tumor necrosis (P < 0.0001). CONCLUSIONS: A change in the tumor uptake of thallium-201 scintigraphy after preoperative chemotherapy can predict the tumor necrosis in osteosarcoma precisely. Thallium scintigraphy is a noninvasive technique and seems to be more useful than angiography in assessing the response of osteosarcoma to preoperative chemotherapy.

Adolescent↗

PubMed1999

Co-expression of 3-ketoacyl-ACP reductase and polyhydroxyalkanoate synthase genes induces PHA production in Escherichia coli HB101 strain.

The Escherichia coli 3-ketoacyl-ACP reductase gene (fabGEc) was cloned using a PCR technique to investigate the metabolic link between fatty acid metabolism and polyhydroxyalkanoate (PHA) production. Three plasmids respectively harboring fabGEc and the poly-3-hydroxyalkanoate synthesis genes phaCAc and phaC1Ps from Aeromonas caviae and Pseudomonas sp. 61-3 respectively were constructed and introduced into E. coli HB101 strain. On a two-stage cultivation using dodecanoate as the sole carbon source, recombinant E. coli HB101 strains harboring fabGEc and phaC genes accumulated PHA copolymers (about 8 wt% of dry cell weight) consisting of several (R)-3-hydroxyalkanoate units of C4, C6, C8, and C10. It has been suggested that overexpression of the fabGEc gene leads to the supply of (R)-3-hydroxyacyl-CoA for PHA synthesis via fatty acid degradation.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗

PubMed1999

High-performance liquid chromatographic-fluorimetric assay for cathepsin A (lysosomal protective protein) activity.

A rapid and sensitive assay for the determination of cathepsin A activity is reported. This method is based on fluorimetric detection of a dansylated peptide, 5-dimethylaminonaphthalene-1-sulfonyl-L-Phe, enzymatically formed from the substrate 5-dimethylaminonaphthalene-1-sulfonyl-L-Phe-L-Leu, after separation by high-performance liquid chromatography using a C18 reversed-phase column and isocratic elution. This method is sensitive enough to measure 5-dimethylaminonaphthalene-1-sulfonyl-L-Phe at concentrations as low as 300 fmol, yields highly reproducible results and requires less than 7.0 min per sample for separation and quantitation. The optimum pH for cathepsin A activity was 4.5-5.0. The Km and Vmax values were respectively 14.9 microM and 27.91 pmol/microg/h with the use of enzyme extract obtained from mouse kidney. Cathepsin A activity was strongly inhibited by Ag+, Hg2+, diisopropylfluorophosphate and p-chloromercuriphenylsulphonic acid. Among the organs examined in a mouse, the highest specific activity of the enzyme was found in kidney. The sensitivity and selectivity of this method will aid in efforts to examine the physiological role of this peptidase.

Animals↗

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↗