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Biomedical subjects

A Mizuguchi

Publications and source records attributed to A Mizuguchi.

At least 19 recordsLinked to original sources
PubMed1996

Differential responses between CA1 pyramidal cells and granule cells to ischemic insult in rat hippocampal slices.

Differential responses between CA1 pyramidal cells (PCs) and granule cells (GCs) to transient ischemic insults (oxygen and glucose deprivation, Hypo center dot G(-)) were studied in rat hippocampal slices using simultaneous recordings of membrane potentials and intracellular Ca2+ concentrations ([Ca2+]i). The average resting membrane potentials before Hypo center dot G(-) were significantly different between PCs (-66.5 +/- 1.5 mV) and GCs (-78.5 +/- 2.0 mV). In PCs, Hypo center dot G(-) produced an initial hyperpolarization and a subsequent rapid and large depolarization. In contrast, in GCs, Hypo center dot G(-) produced a gradual depolarization with an initial slight hyperpolarization. [Ca2+]i increased corresponding to the depolarization. The [Ca2+]i levels during Hypo center dot G(-) and after reoxygenation were significantly higher in the CA1 than in the dentate gyrus. These results suggest that PCs are more susceptible to Hypo center dot G(-) than GCs, as judged by the speed of depolarization and the elevation in [Ca2+]i.

Animals↗
PubMed1992

[Clinical application of 31P MRS to malignant liver tumors--with an emphasis on evaluation of response to therapy].

Malignant liver tumors in 19 cases (13 hepatomas and 6 metastatic tumors) were studied by 31P magnetic resonance (MR) spectroscopy. Five healthy volunteers were also studied. Volume localization was performed using the ISIS sequence. Compared with normal liver, the MR spectra of malignant tumors showed an elevated phosphomonoester (PME) peak relative to beta ATP (p less than 0.005), and tumors were slightly alkaline (pH 7.32 +/- 0.08) before therapy. Nine cases of hepatomas responding to chemoembolization showed extremely reduced signal intensity of spectra. Tumor pH was compared before and after therapy in four cases that showed good response to therapy, and was elevated in all of them. Three metastatic tumors with good response showed reductions in PME and ATP after therapy. MR spectroscopy with adequate localization technique is useful in demonstrating the response of malignant tumors to therapy.

Carcinoma, Hepatocellular↗
PubMed1991

An observation on hitherto unknown corticospinal fibers that descend between the tractus corticospinalis lateralis and ventralis in the cat.

Following injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) into the pericruciate (sensorimotor) cortex on one side in the cat, we found labeled fibers surrounding the ventral horn of the spinal cord bilaterally, in addition to the crossed and the uncrossed lateral, ventral and dorsal corticospinal tracts (CSTs). These hitherto unknown fibers, which could be traced to the caudal end of the L2 segment, were predominantly contralateral to the WGA-HRP injection side. This study indicates the presence of newly recognized CST fibers in the cat.

Animals↗
PubMed1991

Axonal projections from the pontine pneumotaxic region to the nucleus raphe magnus in cats.

In 15 pentobarbital anesthetized and vagotomized cats, 60 non-respiratory units recorded from the medial parabrachial and Kölliker-Fuse nuclear complex (NPBM-KF), were found to be antidromically activated by electrical stimulation of the nucleus raphe magnus (NRM). Seven respiratory units (6 inspiratory, 1 expiratory), comprising 8.0% of the 87 respiratory units examined, were also antidromically activated by stimulation of the NRM. The antidromic latencies ranged from 0.4 to 2.5 ms (mean 1.2 ms). In 6 cats, following injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, a number of retrogradely labelled neurons were observed mainly in the NPBM-KF complex, and some in subcoeruleus nucleus and adjacent tegmental field. These results demonstrate that predominantly non-respiratory and a portion of respiratory neurons in the rostral pons, especially in the NPBM-KF complex, send a monosynaptic axonal projection to the NRM. It is suggested that the NPBM-KF to NRM pathway could be, in part, involved in the control of respiration as well as nociception control.

Animals↗
PubMed1990

Descending axonal projections from the medial parabrachial and Kölliker-Fuse nuclear complex to the nucleus raphe magnus in cats.

In 9 Nembutal-anesthetized and vagotomized cats, a total of 42 units, including 2 respiratory units, recorded from the medial parabrachial (NPBM) and Kölliker-Fuse (KF) nuclear complex were found to be antidromically activated by electrical stimulation of the nucleus raphe magnus (NRM). The latencies ranged from 0.4 to 2.5 ms (mean 1.1 ms). In 5 cats, following injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, a number of retrogradely labelled neurons were observed in the rostral pons, mainly in the NPBM, KF and nearby pontine area. These results demonstrate that mainly non-respiratory neurons in the rostral pons, especially in the NPBM and KF nucleus, send monosynaptic axonal projections to the NRM.

Animals↗
PubMed1990

[Effects on blood coagulation-fibrinolytic system after transcatheter hepatic arterial therapy in cases of hepatocellular carcinoma analyzed by plasma levels of plasmin-alpha 2-PI complex, D dimer and thrombin-ATIII complex].

To clarify the effects on blood coagulation-fibrinolytic system after transcatheter hepatic arterial therapy for cases of hepatocellular carcinoma (HCC), plasma levels of Plasmin-alpha 2PI complex (PIC), Ddimer and Thrombin-ATIII (TAT) before and after therapy were measured by EIA, in addition to other conventional coagulofibrinolytic parameters. In the group (9 cases) treated with intra-arterial injection of adriamycin, there were no significant changes of coagulofibrinolytic parameters except for Ddimer (P less than 0.05) which was elevated 1-2 days after therapy. However, only two cases in whom plasma PIC, Ddimer and TAT levels were clearly elevated before therapy, showed further marked elevation of those parameters after therapy. In the group (29 cases) treated with intra-arterial injection of adriamycin-lipiodol suspension, whether or not embolized with gelfoam, plasma PIC, Ddimer and TAT levels were significantly elevated (P less than 0.01) after therapy, as well as other conventional coagulofibrinolytic parameters. These results indicate that hypercoagulable and hyperfibrinolytic states were induced by treatment. Moreover, the secondary hyperfibrinolytic state tended to persist longer than the hypercoagulable state. The 14 cases embolized with gelfoam seemed to have more apparent effects on blood coagulation-fibrinolytic system than cases not treated with gelfoam. Therefore, we conclude that caution and prophylaxis for the occurrence of disseminated intravascular coagulation are necessary for transcatheter arterial therapy for cases of HCC.

Antithrombin III↗
PubMed1990

[Qualitative analysis of tissue plasminogen activator in plasma obtained from various liver diseases by gel filtration and affinity chromatography].

Tissue plasminogen activator (t-PA) in plasma obtained from patients with acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma, drug-induced intrahepatic cholestasis, obstructive jaundice, fulminant hepatitis or disseminated intravascular coagulation (DIC), was analysed chromatographically. Liver disease cases showed a new peak (peak C) on HPLC fractionation. The protein of peak C had a lower molecular weight than ovalbumin. Lysine- and zinc- chelating affinity chromatography revealed that the peak C consist with the light chain (L-chain) of t-PA. The L-chain was also found in patients with DIC, but disappeared after improvement of DIC. Therefore, it was suggested that appearance of the L-chain would be related to acceleration of secondary fibrinolysis in plasma. The L-chain was especially high in plasma obtained from patients with decompensated liver cirrhosis. These results indicated that high increase of the L-chain in cases of severe liver disease may be due to either impaired clearance of t-PA in the liver or secondary hyperfibrinolysis accompanied by DIC. We concluded that determination of the L-chain of t-PA may contribute to clarify the mechanism of hyperfibrinolysis in liver diseases.

Chromatography, Affinity↗
PubMed1990

[Cardiac output monitoring by impedance cardiography in cardiac surgery].

The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients.

Aged↗