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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

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

Acceleration of atherosclerotic lesions in transgenic mice with hypertension by the activated renin-angiotensin system.

The present study was designed to investigate the development of atherosclerotic lesions in hypertensive transgenic mice carrying both the human renin and angiotensinogen genes (Tsukuba hypertensive mice; THM). THM and C57BL/6J control mice 2 to 3 months of age were fed with either an atherogenic or a normal diet for 14 weeks. Although the systolic blood pressure of either strain remained the same regardless of diet, it was significantly higher in THM than in C57BL/6J on both diets. Total plasma cholesterol concentrations in mice on the atherogenic diet were significantly higher than those in mice fed the normal diet. Lipoprotein profiles of cholesterol in THM were fundamentally similar to those in C57BL/6J on either the atherogenic or normal diet. Compared with controls, however, microscopic analyses revealed accelerated damage of cellular structure in the aortic root in THM fed with the atherogenic diet. Remarkably, the surface area of atherosclerotic lesion in THM was shown by quantitative image analysis to be 4 times larger than that in C57BL/6J on the same atherogenic diet. These findings suggested that hypertension induced by the activated renin-angiotensin system is involved in the development of atherosclerotic lesions. Therefore, THM should be a useful animal model for the study on the pathogenesis of atherosclerosis.

Angiotensinogen↗
PubMed1997

[Hemorheological effects of autologous blood storage before surgery for cardiac valvular diseases].

The hemorheological effects of autologous blood storage with or without the use of erythropoietin were examined before surgery for valvular disease. There was no rheological difference between patients with aortic (16 cases) or mitral (10 cases) valve disease. Before storage, the levels of hematocrit, whole blood viscosity, and especially coefficient of rheology, were lower (p < 0.05) in the blood stored with erythropoietin, but this difference disappeared after storage. The plasma viscosity of both groups did not change before and after storage. The viscosity of blood was equalized after the storage of blood, irrespective of the use of erythropoietin.

Adult↗
PubMed1997

[Anesthetic management for a patient with pure autonomic failure].

Pure autonomic failure is characterized by orthostatic hypotension, sweating disorder, urinary incontinence, and syncope. A 64 year-old man with pure autonomia failure was scheduled for suprapubic prostatectomy. We monitoring direct arterial pressure and inserted pulmonary artery catheter prior to the induction of anesthesia. General anesthesia was induced with diazepam 10 mg, fentanyl 0.3 mg, and vecuronium 8 mg for tracheal intubation. Anesthesia was maintained with sevoflurane (0.2-1.5%), 60% nitrous oxide in oxygen supplemented with intermittent epidural anesthesia. During anesthesia, blood loss was immediately replaced with banked blood because autonomic failure could not compensate hypovolemia well. Epidural anesthesia in this patient was considered to cause less hypotension than in patients with normal autonomic function. Therefore, we think epidural anesthesia is a useful anesthesia method for patients with pure autonomic failure. The emergence from anesthesia was smooth and no complications were seen during the perioperative period.

Anesthesia, Epidural↗
PubMed1997

[Genetically engineered mice for study of human hypertension].

Human essential hypertension is generally recognized as a multifactorial disease based on genetic diathesis. Despite the usefulness of SHR and Dahl rats as laboratory tools, the genetic diathesis including the development of hypertension in these rats remains unclear. Rapid advances in embryonic engineering and molecular biological techniques may make it possible to develop transgenic mice and gene-targeted mice and open new avenues for the molecular investigation of human disease. This report introduces genetically engineered mice with hypertension and hypotension.

Animals↗
PubMed1997

[The change of hepatic energy status after transcatheter arterial embolization (TAE) for hepatocellular carcinoma--a study using 31P-MRS].

In six patients with hepatocellular carcinoma, adenosine triphosphate (ATP) phosphomonoester (PME), phosphoric acid (Pi) and pH were measured before and after transcatheter arterial embolization (TAE), using 31P-magnetic resonance spectroscopy (MRS). The effectiveness of TAE was judged by the extent of lipiodol accumulation within the tumor and change in serum alphafetoprotein level. The pH within the tumor decreased 2-9 days after TAE in all the cases, and beta ATP/Pi ratio decreased when TAE was effective, whereas the ratio did not decrease when TAE was ineffective. The beta ATP/Pi ratio measured by 31P-MRS seems to be a useful, non-invasive marker of the anti-tumor effect of TAE, although further investigation is needed.

Adenosine Triphosphate↗
PubMed1997

A new simple assay for determining aminoglycoside inactivation in intact cells of Pseudomonas aeruginosa.

Intact cells of aminoglycoside (AG) antibiotic-resistant Pseudomonas aeruginosa usually do not inactivate AG, even though they possess the AG-modifying enzyme. An assay method for determining the activity of inactivating enzyme in intact cells of streptomycin-resistant P. aeruginosa was previously reported. Although this assay method was applied to the determination of the activity of kanamycin (KM)-inactivating enzymes, it could not apply to some of the KM-resistant strains. A new simple assay method has now been investigated for determining the activity of KM-inactivating enzyme in intact cells of clinically isolated KM-resistant P. aeruginosa. The determination of AG-inactivating enzyme activity was attempted using lysozyme for release of the inactivating enzymes in washed cells, and both DNase and RNase were added to digestion of the nucleic acids released by bacteriolysis. This lysozyme-DNase-RNase (LDR) method has facilitated the confirmation of the presence of AG-inactivating enzyme in the strains used. In addition, the LDR technique was applicable to the determination of inactivating enzyme activity for various AGs other than KM. Since this simple assay method can determine any type of AG-inactivating enzyme activity of various P. aeruginosa strains, it may contribute significantly to the rapid selection of drugs in clinical use.

Anti-Bacterial Agents↗
PubMed1997

[Noninvasive hemodynamic assessment of internal thoracic artery grafts using duplex echocardiography from supraclavicular fossa--a comparison with Doppler catheter method].

We evaluated the usefulness of noninvasive hemodynamic assessment of internal thoracic artery grafts (ITAGs) using duplex Doppler echocardiography from the supraclavicular fossa (transcutaneous pulsed Doppler method: PD method). Eighteen ITAGs were examined by PD method in comparison with Doppler catheter method using Doppler flowire (DC method). The hemodynamic indices used were the diastolic/systolic peak velocity ratio (DSVR) and the diastolic fraction of time-velocity integral (DF) in the ITAGs. A significant linear correlation was seen both in DSVR and DF between these two methods (p < 0.01). The subjects were assigned to two groups according to angiographic findings Group A (Gr-A: 5 grafts) with string sign including significant graft stenosis and group B (Gr-B 13 grafts) with good patency. In both PD and DC methods, DSVR and DF were significantly lower in Gr-A than in Gr-B (p < 0.01). The blood flow pattern was thus systolic dominant in the grafts with string sign, while it was diastolic dominant in the grafts with good patency. In some grafts in Gr-B, however, both DSVR ad DF were as low as that in Gr-A. Responding to pacing, Gr-B further increased both DSVR and DF, but Gr-A did not. As a result, the difference between both groups was further distinguished. In summary, ITAG function can be assessed by the noninvasive PD method. Interventions such as exercise, dobutamine infusion may make it more accurate, particularly in evaluating borderline data.

Aged↗
PubMed1997

Effect of training program based on anaerobic threshold in the early phase after acute myocardial infarction.

We devised a new physical training program on the basis of anaerobic threshold for rehabilitation in the early phase of acute myocardial infarction. Forty-four patients were divided into two groups, control and training. We measured the left ventricular ejection fraction using nuclear stethoscopy during the treadmill test and calculating radioactive cardiac output. In the training group, anaerobic threshold and exercise time to the anaerobic threshold point were significantly increased, and stroke volume at rest measured by the dye dilution method increased significantly. Radioactive cardiac output during exercise also increased after the exercise therapy. These results indicate that the rehabilitation program consisting of physical training based on the anaerobic threshold is effective.

Adult↗
PubMed1996

Ser-27, Tyr-10 and Tyr-7 in the alpha-chain of pig stomach H+,K(+)-ATPase as Ca(2+)-dependent phosphorylatable sites by intrinsic and extrinsic protein kinases.

When pig stomach membrane H+,K(+)-ATPase preparations were incubated with [gamma-32P]ATP, Mg2+ and Ca2+, reversible phosphorylation of specific Tyr and Ser residues in the N-terminal alpha-chain of H+,K(+)-ATPase occurred without any detectable phosphorylation in other regions of the alpha-chain. Mild tosylphenylalanyl chloromethyl ketone trypsin treatment followed by reverse-phase column chromatography yielded three radioactive peptide peaks. The first peak contained both Tyr10(32P) and Tyr7(32P) and the second peak contained Tyr10(32P). The third peak contained Ser27(32P) which was also obtained after trypsin treatment of partially purified H+,K(+)-ATPase preparations phosphorylated with protein kinase-C + Ca2+ or protein kinase-A. This is the first demonstration of Ca2(+)-dependent phosphorylation of the alpha-chain of H+,K(+)-ATPase by protein kinases.

Amino Acid Sequence↗
PubMed1996

Sequence analysis of normal and rearranged NSP5 genes from human rotavirus strains isolated in nature: implications for the occurrence of the rearrangement at the step of plus strand synthesis.

We determined the nucleotide sequences of normal and rearranged NSP5 genes from the human rotavirus strains (Mc323 and Mc345, respectively) which had previously been isolated from Thai infants with diarrhea in the same epidemic season. While the two strains shared G serotype 9 specificity and subgroup I specificity and they showed a high level of overall genomic relatedness to each other, they exhibited different RNA profiles; a long pattern for Mc323 and a super-short pattern for Mc345. Their NSP5 sequences were more closely related to those of porcine rotaviruses than to those of human rotaviruses. Mc345 NSP5 gene was shown to have concatemerization. In a head-to-tail orientation resulting in its length being 1182 bp, as compared with the Mc323 NSP5 sequence which was 664 bp in length. Sequence analysis suggested that the rearrangement found in the strain Mc345 occurred at the step of plus strand synthesis.

Base Sequence↗
PubMed1996

A human canalicular multispecific organic anion transporter (cMOAT) gene is overexpressed in cisplatin-resistant human cancer cell lines with decreased drug accumulation.

By targeting the ATP binding conserved domain in three ATP binding cassette superfamily proteins (P-glycoprotein, multidrug resistance protein, and cystic fibrosis transmembrane regulator), we isolated the cDNA of a new ATP binding cassette superfamily that was specifically enhanced in a cisplatin-resistant human head and neck cancer KB cell line. A human clone homologous to rat canalicular multispecific organic anion transporter (cMOAT) was found and designated human cMOAT. Fluorescence in situ hybridization demonstrated the chromosomal locus of the gene on chromosome 10q24. The human cMOAT cDNA hybridized a 6.5-kb mRNA that was expressed 4- to 6-fold higher by three cisplatin-resistant cell lines derived from various human tumors exhibiting decreased drug accumulation. Human cMOAT may function as a cellular cisplatin transporter.

Adenosine Triphosphate↗
PubMed1996

Drug-induced down-regulation of topoisomerase I in human epidermoid cancer cells resistant to saintopin and camptothecins.

The anticancer agent saintopin induces DNA cleavage mediated by both topoisomerase (topo) I and topo II in vitro through stabilization of the reversible enzyme-DNA cleavable complex. We established saintopin-resistant cell lines (KB/STP-1 and KB/STP-2) from human epidermoid cancer KB cells by stepwise exposure to increasing doses of the drug. KB/STP-1 and KB/STP-2 cells showed 12- and 44-fold increases, respectively, in resistance to saintopin relative to that of KB cells. Both saintopin-resistant cell lines showed only small reductions in sensitivity to the topo II inhibitor etoposide but developed marked cross-resistance to the topo I-targeting camptothecin derivative CPT-11 [(4s)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbony loxy] dione hydrochloride trihydrate] and its active form, SN-38 (7-ethyl-10-hydroxycamptothecin). In contrast, both KB/STP-1 and KB/STP-2 cells showed increased collateral sensitivity to cisplatin, a nitrosourea derivative, mitomycin C, and UV light. The protein concentration, activity, and mRNA abundance of both topo I and topo II were similar in KB/STP-1, KB/STP-2, and the parental KB cells. There were no significant changes in the drug-stabilized topo-DNA cleavable complex formation in KB and KB/STP-2 cells. Two point mutations were detected in topo I cDNA from KB/STP-2 cells, but these were also present in KB cells. Topo I mRNA abundance decreased markedly immediately after exposure of KB/STP-2 cells to saintopin; no such effects were apparent in KB cells. In contrast, topo II mRNA was not markedly affected by saintopin in either KB or KB/STP-2 cells. Treatment with CPT-11 or SN-38 also induced a markedly greater and more persistent reduction in topo I mRNA abundance in KB/STP-2 cells than in KB cells. Etoposide had no marked effect on topo I mRNA abundance in either KB/STP-2 or KB cells. Topo I mRNA was highly unstable in KB/STP-2 cells in comparison to KB cells when incubated with saintopin. This novel regulation of topo I mRNA by topo I-targeting agents could be associated with acquirement of drug resistance to saintopin or SN-38/CPT-11 in KB/STP-2 cells.

Antibiotics, Antineoplastic↗
PubMed1996

Leukocyte depletion attenuates reperfusion injury in patients with left ventricular hypertrophy.

BACKGROUND: Reperfusion injury can occur after a long period of aortic cross-clamping in patients with left ventricular hypertrophy during open-heart surgery, even with the most up-to-date techniques of myocardial protection. In the present study, we examined whether leukocyte depletion as an adjunct to terminal blood cardioplegia (LDTC) attenuates reperfusion injury in patients with left ventricular hypertrophy (LV mass, >300 g; left ventricular end-systolic volume index, >100 mL/m2) in a group of 30 patients undergoing aortic valve replacement. METHODS AND RESULTS: We used basic cold potassium crystalloid cardioplegic solution. Terminal blood cardioplegic solution (TC) or LDTC was accomplished by mixing a cold potassium crystalloid cardioplegic solution with warm arterial blood obtained through cardiopulmonary bypass and administered to the aortic root for the first 10 minutes of reperfusion. During delivery of LDTC, warm arterial blood was passed through a leukocyte-removal filter. Patients were randomized into one of three groups for reperfusion: whole blood (WB) (n=10), TC (n=10), and LDTC (n=10). Left ventricular biopsies were obtained before ischemia, at the end of ischemia, and 15 minutes after reperfusion. Semiquantitative scoring for ultrastructural alterations indicated that the LDTC group achieved significantly better recoveries of both scores at reperfusion for myocyte damage and for endothelial cell damage of capillaries than did the WB and TC groups. The LDTC group had significantly fewer neutrophils adhering to endothelial cells at reperfusion and a lower level of malondialdehyde derived from myocardium than did the WB and TC groups. Regarding the clinical data, the LDTC group had a lower maximum creatine kinase-MB, a higher percentage of spontaneous defibrillation, a lower pulmonary capillary wedge pressure, and a lower requirement for dopamine that did the WB group, whereas the TC group failed to do better than the WB group. CONCLUSIONS: These results demonstrate that leukocyte-depleted reperfusion is potentially beneficial as an adjunct to terminal cardioplegia during cardiac surgery to attenuate reperfusion injury in patients with left ventricular hypertrophy.

Adult↗
PubMed1996

Applicability of monoclonal antibody Fab fragments as a carrier of neocarzinostatin in targeting chemotherapy.

Two types of fragments of MAb A7 were produced to improve the efficacy and safety in targeting chemotherapy with neocarzinostatin. In this study, 125I-labeled F(ab')2 and Fab fragments of MAb A7 and 125I-labeled MAb A7 were injected intravenously into mice with pancreatic carcinoma xenografts, and the accumulation of each antibody in the tumors was compared. A greater amount of the 125I-labeled Fab fragments of MAb A7 localized in the tumor 2 h following the injection than was observed with the other probes. Relatively less 125I-labeled MAb A7 localized in the tumor 2 h following the injection than was observed with the other two probes. Moreover, reaction of rabbit antimouse IgC with the Fc portion, which is the most immunopotent region of the Fab and F(ab')2 fragments of MAb A7 and MAb A7, was determined by ELISA; the weakest reaction was observed with the Fab fragments of MAb A7. These results suggest that the Fab fragments of MAb A7 may be more suitable carriers of an anticancer drug that is inactivated rapidly in the blood, such as NCS, in targeting chemotherapy than either intact MAb A7 or the F(ab')2 fragments of MAb A7.

Animals↗
PubMed1996

The valine catabolic pathway in human liver: effect of cirrhosis on enzyme activities.

The activities of key enzymes in the valine catabolic pathway--branched-chain aminotransferase, branched-chain alpha-keto acid dehydrogenase complex, methacrylyl (MC)-coenzyme A (CoA) hydratase (crotonase), and 3-hydroxyisobutyryl-CoA (HIB-CoA) hydrolase--were measured in normal and cirrhotic human livers. Unlike rat liver, which does not contain branched-chain aminotransferase, the aminotransferase activity in the normal liver was measurable and is increased somewhat in cirrhosis of the human liver. The total activity of branched-chain alpha-keto acid dehydrogenase complex in the normal human liver was approximately 1% of that in rat liver, and 20% to 30% of the complex was in the active form in both normal and cirrhotic livers. Only the actual activity of the enzyme was significantly decreased by cirrhosis. These results suggest that human liver is less active than rat liver in the catabolism of branched-chain amino and alpha-keto acids. Activities of MC-CoA hydratase and HIB-CoA hydrolase in human liver were very high compared with that of branched-chain alpha-keto acid dehydrogenase complex, suggesting an important role for these enzymes in catabolism of a potentially toxic compound, MC-CoA, formed as an intermediate in the catabolism of valine and isobutyrate. Cirrhosis resulted in a significant decrease in HIB-CoA hydrolase activity but had no effect on the citrate synthase activity, suggesting that the decrease in HIB-CoA hydrolase activity does not reflect a general decrease in mitochondria but that it may contribute to cellular damage that culminates in liver failure.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗