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Biomedical subjects

K Taniguchi

Publications and source records attributed to K Taniguchi.

At least 415 records · Page 23Linked to original sources
PubMed1994

Improvement of impaired brain monoamine metabolism by the cognition-enhancing agent nefiracetam after microsphere-induced cerebral embolism in rats.

Nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide DM-9384, CAS 77191-36-7), a pyrrolidone (cyclic GABA) derivative, is a newly developed cognition-enhancing (nootropic) agent. In the present study, the effects of nefiracetam on cerebral monoamine metabolism in rats after microsphere-induced cerebral embolism have been examined. For cerebral embolization, microspheres were injected into the left internal carotid artery. Nefiracetam (3, 10 and 30 mg/kg p.o.) was administered daily to the animals for 13 days from the 9th day after the operation. The levels of DA, DOPAC and HVA in the control (embolism-induced, but untreated) group were significantly decreased compared with those of the normal (non-operated) group. In animals treated with nefiracetam (3 mg/kg p.o.), these monoamine levels were higher than controls in the cortex and hippocampus, whereas they were not significantly changed in the striatum. 5-HT contents in the control group significantly decreased from normal levels in the cortex and hippocampus, on which nefiracetam at various doses had no effect. The levels of 5-HIAA in the control group also decreased, which were, however, significantly increased by 3 mg/kg of nefiracetam. The results suggest that nefiracetam has improving actions on the dysfunction of the dopaminergic and serotonergic systems induced by cerebral embolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

[Intra-ocular pressure changes during laparoscopic cholecystectomy].

Intra-ocular pressure (IOP) was measured during laparoscopic cholecystectomy (n = 20) under continuous epidural block and nitrous oxide-oxygen anesthesia. There was a slight but significant increase in IOP and peak airway pressure when the abdominal CO2 insuffration was started, and the IOP recovered to the preoperative level after the postural change to the head-up position. It was not associated with any significant change in mean arterial pressure and end-tidal CO2. In one ocular hypertension case undergoing laparoscopic chorecystectomy and appendectomy, however, there was profound increase in IOP during abdominal CO2 insuffration with head down position. We speculate that it was due to the effect of increased CVP with abdominal CO2 insuffration and postural change on the IOP. Thus the laparoscopic operation with head-down position should be avoided in patients with ocular hypertension.

Anesthesia, Epidural↗
PubMed1994

[Atypical MDR].

Multiple drug resistance(MDR) is a major clinical obstacle in cancer chemotherapy. Acquirement of MDR phenotype in cancer cells is often associated with enhanced expression of human MDR-1 gene: MDR-1 gene codes membranous P-glycoprotein which catalyses energy-dependent outward transport of anticancer agents. By contrast, MDR cancer cell lines without overexpression of P-glycoprotein are called as atypical MDR (at MDR) cells. The acquirement of at MDR has been shown to be partly associated with altered DNA topoisomerase II. Furthermore, a new ATP binding cassette (ABC) family, MRP gene has just recently shown to involve in acquirement of at-MDR in cancer cell lines, which do not express both altered topoisomerase II and P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[Evaluation of a new nitric oxide delivery system during mechanical ventilation].

A new nitric oxide delivery and continuous monitoring system is described. During mechanical ventilation, this new system connected with Siemens Servo 900C ventilator was shown to be able to provide a constant inspired NO concentration (10-100 ppm) using chemiluminescence technique for NO analysis. Gas was analysed at the mixing chamber in front of the ventilator inlet and inspiratory tube connected with the soda-lime carbon-dioxide absorber. Both NO concentrations showed a good correlation (r = 0.99). The actual NO concentration from the NO supply cylinder was 1154 ppm and NO2 concentration was 14 ppm. In mongrel dogs, after 20 minutes of NO inhalation (10-100 ppm), the blood methemoglobin level reached a peak value of 2.2% starting from the pre-inhalation level of 0%. To optimize the safety of the clinical application of NO, its concentration should be measured continuously with chemiluminescence technique.

Animals↗
PubMed1994

[Aging changes of cerebral high intensity areas on T2-weighted MRI--a study in medical checkup patients].

To determine normal aging process of the brain, cerebral T2-weighted MRI was evaluated in 400 healthy individuals who visited our hospital for routine medical checkups. The results are summarized as follows. 1) High intensity areas (measuring 2 mm x 2 mm or more) were observed most frequently in the cerebral white matter including the corona radiata (CR). The incidence of these areas increased linearly with age, and approached about 50% in the patients of the seventh decade. 2) High intensity areas in the basal ganglia (BG) were the second commonest. High intensity areas were rarely seen in the thalamus (TH) and pontine base (PO). 3) High intensity areas were confined to the CR (66.9%) in the majority of the cases, while there were few cases having these areas restricted to the BG, TH and PO; that is, most of them were accompanied by additional high intensity areas in the CR. 4) Periventricular hyperintensity areas increased in size with age, and were prominent in those who had multiple or large high intensity areas in the CR, or those who had signal hyperintensity in the BG, TH or PO.

Adolescent↗
PubMed1994

[Clinical evaluation of diazepam suppository for premedication in children].

Anesthesiologists need a safe and effective premedication before general anesthesia and want to help decrease anxiety and minimize psychologic trauma to children. Therefore, we evaluated diazepam suppository (0.5 mg.kg-1 body weight) administered to 21 children before minor surgery under general anesthesia. We evaluated the sedative effect of the diazepam suppository (tablet) on the arrival at the operating room, during anesthesia induction and in the recovery room. On the arrival at operating room, 86% of children were sedated, and 65% of children could be induced smoothly under mask. There was no delayed emergence. Plasma diazepam level at induction was 376.5 +/- 28.4 ng.ml-1, which is the level needed for sedation. We conclude that diazepam suppository is a useful drug for premedication in children.

Anesthesia, General↗
PubMed1993

Phosphorylation of half and all sites in H+,K(+)-ATPase results in opposite changes in tryptophan fluorescence.

The Trp fluorescence increased accompanying phosphorylation by ATP and Acetyl phosphate (AcP) in pig stomach H+,K(+)-ATPase, respectively, to maximum values of 0.86 and 0.37%. The stoichiometry of the maximum amount of phosphoenzyme formed from ATP, that from AcP, that from inorganic phosphate (Pi), and the maximum amount of ATP binding to the enzyme was shown to be close to 1:2:2:2. Phosphoenzymes formed were shown to be turning over. The addition of K+ reduced the amount of phosphoenzyme from ATP to one-tenth but reduced those from AcP or Pi to only the half. The data show that the Trp fluorescence increased with phosphorylation of half of the sites but decreased with phosphorylation of all sites.

Adenosine Triphosphate↗
PubMed1993

Fate of right ventricular hypertrophy in tetralogy of Fallot after corrective surgery.

To elucidate the reversibility of right ventricular (RV) myocardial hypertrophy in tetralogy of Fallot (TF), 30 patients underwent RV endomyocardial biopsies 1 to 25 years (mean 9.7 +/- 6.6) after corrective surgery. Myocardial cell diameter was evaluated by comparing histopathologic data with preoperative patients with TF and normal subjects. As a whole, postoperative cell diameter was smaller than that of age-matched preoperative patients with TF, and larger than that of age-matched normal subjects. In 7 patients without significant residual pulmonary stenosis whose preoperative data were also available, cell diameter significantly decreased after surgery (17.1 +/- 2.1 to 14.0 +/- 2.1 microns, p < 0.01). There was a positive correlation between postoperative cell diameter and age at study (p < 0.01). To negate the influence of age, cell diameter was expressed in terms of a percentage of age-matched normal values (percent cell diameter). There was no significant correlation between percent cell diameter and age at surgery, age at study or the follow-up periods. There were positive correlations between percent cell diameter and the following parameters: RV systolic pressure (p < 0.05), percent normal RV end-diastolic (p < 0.05) and end-systolic (p < 0.01) volumes. These results demonstrate that RV myocardial hypertrophy in TF can regress to some extent after corrective surgery if significant residual pulmonary stenosis is avoided.

Adolescent↗
PubMed1993

Subdivisions of the accessory olfactory bulb, as demonstrated by lectin-histochemistry in the golden hamster.

Lectin-binding patterns in the accessory olfactory bulb (AOB) of the golden hamster were investigated histochemically with 21 biotinylated lectins. The AOB was divided into rostral and caudal halves according to binding patterns of 16 lectins, WGA, s-WGA, LEL, STL, DSL, BSL-II, DBA, SBA, BSL-I, VVA, SJA, PNA, ECL, UEA-I, Con A and PSA. The caudal half of the AOB was further subdivided into anterior 2/3 and posterior 1/3 by 10 lectins, WGA, s-WGA, BSL-II, DBA, SBA, BSL-I, VVA, SJA, PNA and ECL. In addition, the rostral half of the AOB was subdivided into anterior 1/4 and posterior 3/4 by one lectin, PNA. Thus, the AOB of the golden hamster was divided into 4 divisions on the basis of lectin-binding patterns.

Animals↗
PubMed1993

Reversible changes in the fluorescence energy transfer accompanying formation of reaction intermediates in probe-labeled (Na+,K+)-ATPase.

A preparation of pig kidney Na+,K(+)-ATPase showed changes in fluorescence energy transfer between probes bound to the alpha-subunit. Excitation (305 nm) of an N-(p-(2-benzimidazolyl)phenyl)maleimide (BIPM) probe, which was covalently bound to Cys-964, and excitation (470 nm) of a fluorescein 5'-isothiocyanate (FITC) probe at Lys-501 gave different FITC fluorescence intensity changes at 520 nm in BIPM-FITC doubly labeled enzyme accompanying formation of reaction intermediates. Addition of acetyl phosphate to a Na(+)-bound enzyme (NaE1) to accumulate acetate-sensitive phosphoenzyme (E1P) induced a faster and greater FITC fluorescence decrease when excited at 470 nm than at 305 nm. An oligomycin-sensitive transition of E1P to K(+)-sensitive phosphoenzyme (E2P) was also accompanied by a larger FITC fluorescence decrease when excited at 470 nm. The addition of K+ to [32P]E2P to form a K(+)-bound enzyme (KE2) induced a rapid dephosphorylation (140/s) with both a slow rate of FITC fluorescence increase and a larger fluorescence increase when excited at 470 nm. The addition of Na+ to KE2 induced both a slow increase of FITC fluorescence and a larger fluorescence increase when excited at 470 nm. The data suggest that fluorescence energy transfer from the BIPM to the FITC probe accompanies the processes of migration of Na+ and K+ in the pump molecules. The dynamic fluorescence changes after phosphorylation and dephosphorylation seem to reflect changes in the binding state or the process of migration of these ions.

Acetates↗
PubMed1993

Immunohistochemical demonstration of protein gene product 9.5 (PGP 9.5) in the primary olfactory system of the rat.

Immunohistochemical localization of protein gene product 9.5 (PGP 9.5) was examined in the primary olfactory system of the rat. Receptor cells were intensely immunopositive in the olfactory epithelium, vomeronasal organ and septal olfactory organ of Masara. The mitral cells and some of the short-axon cells of the main olfactory bulb (MOB) were also intensely immunopositive, while the tufted cells of the MOB and the mitral/tufted cells of the accessory olfactory bulb varied in immunoreactivity.

Animals↗
PubMed1993

Cysteine proteinases in rat dorsal root ganglion and spinal cord, with special reference to the co-localization of these enzymes with calcitonin gene-related peptide in lysosomes.

To examine the localization of lysosomal cysteine proteinases, cathepsins B, H, and L, and their correlation with a neuropeptide, calcitonin gene-related peptide (CGRP) in nerve cells, immunocytochemistry was applied to rat dorsal root ganglion (DRG) and spinal cord (SC) of lumbar segments. By light microscopy, granular immunodeposits for cathepsins B and L were localized in small and large nerve cells in DRG and SC. The cathepsin B- and L-positive smaller nerve cells in DRG and large nerve cells in the ventral horn of SC were also immunostained by anti-CGRP. By electron microscopy, nerve cells in DRG and SC contained lysosomes labeled by immunogold particles indicating cathepsins B and L, while immunogold particles for cathepsin L labeled lysosomes of glial cells. Double immunostaining co-localized immunogold particles for cathepsin B or L and CGRP in lysosomes of small nerve cells in DRG and motoneurons in SC. Moreover, cathepsin H was immunocytochemically demonstrated in lysosomes of satellite cells in DRG, while lysosomes of perivascular microglia-like cells were labeled by immunogold particles for cathepsins B, H, and L. The results suggest the possibility that lysosomes in nerve cells participate in regulation of intraneuronal CGRP level by degrading CGRP.

Animals↗
PubMed1993

Transport pathways for macromolecules in the aortic endothelium: I. Transendothelial channels revealed by three-dimensional reconstruction using serial sections.

Three-dimensional organization of structures labeled by horseradish peroxidase as a tracer molecule in rat aortic endothelium was examined to elucidate the transport pathways for macromolecules. Aortic endothelium was divisible morphologically into four distinct parts, i.e., the parajunctional region (JR), peripheral region (PR), organelle region (OR), and nuclear region (NR). Almost all vesicles, intercellular clefts, and phagosomes were labeled by horseradish peroxidase. Peroxidase-positive vesicles tended to gather in the PR, occasional JR, and the upper part of the NR. Ultrathin serial micrographs revealed the transcellular channels composed of vesicles in the PR and JR, and the paracellular channels composed of the intercellular cleft without constrictions of tight and gap junctions. Transcellular channels were subdivided into three morphologically different types, where not only vesicles but invagination of abluminal membrane and intercellular cleft occasionally participated in their formation. Three-dimensional reconstructions from three series of consecutive electron micrographs revealed that almost all peroxidase-positive vesicles were connected directly or indirectly with the cell surface. These results indicate that the transcellular and paracellular channels are the transport pathways for macromolecules in the aortic endothelium and may suggest that the "shuttle" hypothesis is unsuitable to explain transport system for macromolecules because it postulates the existence of many free vesicles in the cytoplasm.

Animals↗
PubMed1993

Transport pathways for macromolecules in the aortic endothelium. II. The distribution analysis of plasmalemmal vesicles reconstructed by serial sections.

Three-dimensional organization of vesicles was examined to elucidate the transendothelial transport properties for macromolecules in rat aortic endothelium using ultrathin serial sections and horseradish peroxidase (HRP) as a tracer molecule. A total number of reconstructing vesicles was 1,298 in nine series of serial electron micrographs, if each vesicular entity was counted as one regardless of composite number of vesicles. The vesicles could be classified into the following six types: HRP-positive luminal, abluminal and intercellular invaginations; HRP-positive channels; HRP-positive and -negative vesicles. The vesicular invaginations and the channels occupied 97.8% and 0.9% of the total vesicles, whereas HRP-positive and -negative free vesicles were found in 0.8% and 0.5%, respectively. The average numerical density of the luminal invagination was 41.1/microns 2 and approximately equal to that of the abluminal invagination (42.0/microns 2), whereas the frequency of the latter was 1.4 times higher than that of the former since the abluminal surface of the endothelium was more irregular to increase a surface area. Each endothelial region varied in the vesicular density and the peripheral region generally showed the higher density, although the transendothelial channels composed of vesicles were not always found in every peripheral region. These results suggest that the shuttle hypothesis is unsuitable to explain "vesicular transport" in the arterial endothelium as well as in the capillary endothelium and that the channels in the peripheral region mainly control transendothelial transport for macromolecules via vesicles.

Animals↗