A conventional approach to chimpanzee cognitionResponse to M.D. Hauser (2000).
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Journal Article↗
Biomedical subjects
N Kawai
Publications and source records attributed to N Kawai.
In vivo antioxidative activity of propolis evaluated by the interaction with vitamins C and E and the level of lipid hydroperoxides in rats.
In vivo antioxidative activity of propolis was evaluated on the basis of ameliorative effects on the oxidative stress induced by vitamin E deficiency in rats. The control group was fed vitamin E-deficient diet, and the propolis group was fed vitamin E-deficient diet supplemented with 1% of propolis for 4 and 8 weeks. Comparisons were made in tissue concentrations of vitamin C, vitamin E, and lipid hydroperoxides between these groups. No significant difference was observed in tissue vitamin E concentration between these groups after both 4 and 8 weeks. After 4 weeks, the plasma vitamin C concentration of the propolis group was significantly higher than that of the control group. After 8 weeks, the tissue concentrations of vitamin C in the kidney, stomach, small intestine, and large intestine of the propolis group were significantly higher than those of the control group. These results suggest that some components of propolis are absorbed to circulate in the blood and behave as a hydrophilic antioxidant that saves vitamin C. The concentration of lipid hydroperoxides in the large intestine of the propolis group was significantly lower than that of the control group after 8 weeks. These results suggest that propolis exerts its antioxidative effect where it is assumed to accumulate, such as on the kidney, where it is excreted, and on the gastrointestinal tract, where propolis influences these tissues even from the outside of the cell.
Animals↗
Adeno-associated virus vector-mediated bcl-2 gene transfer into post-ischemic gerbil brain in vivo: prospects for gene therapy of ischemia-induced neuronal death.
The proto-oncogene bcl-2 is known as an anti-apoptotic gene that confers the ability to block neuronal cell death after transient ischemia. In order to examine whether the bcl-2 gene can be used for protection of ischemic brain injury, we generated adeno-associated virus (AAV) vectors capable of expressing human bcl-2. Replication-defective AAV vectors were found effectively to transfer and express bcl-2 gene in the gerbil hippocampal neurons. Transduction with AAV bcl-2 5 days before forebrain ischemia prevented the DNA fragmentation in the CA1 neurons that is commonly associated with ischemia-induced cell death. Furthermore, the application of AAV bcl-2 as late as 1 h following an ischemic insult also prevented DNA fragmentation in CA1 neurons. These results suggest that the bcl-2 protein has neuroprotective functions that inhibit ischemic cell death and demonstrate the potential of AAV bcl-2 for use in post-ischemic gene therapy in the brain. Gene Therapy (2000) 7, 1244-1249.
Adenoviridae↗
Cyclo-oxygenase-2 inhibitors suppress epithelial cell kinetics and delay gastric wound healing in rats.
BACKGROUND AND AIMS: The present study examined the effects of NS-398, a specific cyclo-oxygenase-2 inhibitor, on gastric mucosal cell kinetics and gastric wound healing following acid-induced injury. METHODS: Male Sprague-Dawley rats were fasted for 24 h and then 0.6 mol/L hydrochloric acid (HCl; 1 mL) was administered into the stomach; NS-398 or indomethacin was administered to the animals 10 min after the acid. Levels of constitutive cyclo-oxygenase (COX-1) and mitogen-inducible cyclo-oxygenase (COX-2) in the gastric mucosa were analysed using western blotting and immunohistochemical staining. The grade of the lesion was assessed using planimetry and histological examination, including immunohistochemistry for proliferating cell nuclear antigen (PCNA). RESULTS: Although there was strong expression of COX-1, there was minimal expression of COX-2 in the gastric mucosa. Expression of COX-2 was enhanced mainly in surface epithelial cells and neck cells following HCl administration. Gastric mucosal ulcers and erosions healed within 48 h, during which time the proliferative zone expanded in the control animals. Indomethacin and NS-398 suppressed the expansion of the proliferative zone and delayed the healing of the gastric injury. CONCLUSION: The present study demonstrated that cyclo-oxygenase-2 inhibitors delay gastric wound healing by suppressing expansion of the mucosal proliferative zone. These results provide evidence that cyclo-oxygenase-2 has an important role in gastric mucosal regeneration.
Animals↗
A new class of neurotoxin from wasp venom slows inactivation of sodium current.
The effects of alpha-pompilidotoxin (alpha-PMTX), a new neurotoxin isolated from the venom of a solitary wasp, were studied on the neuromuscular synapses in lobster walking leg and the rat trigeminal ganglion (TG) neurons. Paired intracellular recordings from the presynaptic axon terminals and the innervating lobster leg muscles revealed that alpha-PMTX induced long bursts of action potentials in the presynaptic axon, which resulted in facilitated excitatory and inhibitory synaptic transmission. The action of alpha-PMTX was distinct from that of other known facilitatory presynaptic toxins, including sea anemone toxins and alpha-scorpion toxins, which modify the fast inactivation of Na+ current. We further characterized the action of alpha-PMTX on Na+ channels by whole-cell recordings from rat trigeminal neurons. We found that alpha-PMTX slowed the Na+ channels inactivation process without changing the peak current-voltage relationship or the activation time course of tetrodotoxin (TTX)-sensitive Na+ currents, and that alpha-PMTX had voltage-dependent effects on the rate of recovery from Na+ current inactivation and deactivating tail currents. The results suggest that alpha-PMTX slows or blocks conformational changes required for fast inactivation of the Na+ channels on the extracellular surface. The simple structure of alpha-PMTX, consisting of 13 amino acids, would be advantageous for understanding the functional architecture of Na+ channel protein.
4-Aminopyridine↗
Treatment of arteriovenous malformation of the brain--preliminary experience.
With the availability of new techniques, such as intravascular embolisation and radiosurgery, the therapeutic approach to arteriovenous malformations (AVMs) of the brain has recently been modified. The present study reports the authors, experiences in treating AVMs over the past 13 years. Spetzler-Martin grading of AVMs was I and II in 19 cases, III in 12, IV in 5 and V in 1 case. Four therapeutic regimens were utilised: surgical resection alone, embolisation and resection, and radiosurgery alone or after surgical resection. Generally, for low-grade AVMs (Spetzler-Martin grades I, II and III), the therapeutic choice was surgical resection in 27 cases, in combination with pre-operative embolisation in two of these patients. Two cases received radiotherapy only and one case received radiosurgery after embolisation, while one case was treated conservatively. Of the five cases of grade IV, four required surgical treatment, whereas the fifth case was treated conservatively. Favourable results (good recovery and moderate disability) were obtained in 96% of the low-grade AVMs as compared with the high-grade AVMs (66%) that had a poor outcome (due to primary brain damage resulting from haemorrhage at the onset in three cases and due to postoperative re-bleeding in one case). This report summarises preliminary experience in treating intracranial AVMs by surgical resection, intravascular embolisation and radiotherapy. Good therapeutic results can be expected by combining these therapeutic modalities.
Adult↗
Expression of cyclooxygenase-2 and nitrotyrosine in human gastric mucosa before and after Helicobacter pylori eradication.
To determine whether cure of Helicobacter pylori infection influences the expression of COX-2 and nitrotyrosine in the distal stomach of humans, biopsy specimens were examined immunohistochemically. H. pylori infection was determined using a rapid urease test, culture and histology. Positive staining of COX-2/nitrotyrosine in the epithelium was expressed as the percentage of stained cells to the total epithelial cells. There was a significant increase in COX-2/nitrotyrosine staining in H. pylori -positive subjects compared with H. pylori -negative subjects. Cure of the infection resulted in a significant decrease in both COX-2/nitrotyrosine staining in all patients (52.1+/-12.1% vs 15. 4+/-7.2%, P<0.001; and 57.3+/-13.6% vs 36.1+/-18.0%, P<0.01, respectively). However, immunoreactivity of COX-2/nitrotyrosine was observed in all cases with intestinal metaplasia even after the cure of H. pylori infection.Thus, cure of H. pylori infection may decrease the risk of gastric carcinogenesis due to COX-2 and NO-related compounds in gastric mucosa but not in those patients with intestinal metaplasia.
Adult↗
Effects of hypothermia on intracranial pressure and brain edema formation: studies in a rat acute subdural hematoma model.
Acute subdural hematoma (SDH) is the most common mass lesion in severe head injury, and brain ischemia is the leading pathophysiological mechanism in the development of secondary brain damage following SDH. Hypothermia has been employed as an effective neuroprotective procedure in clinical and laboratory studies on cerebral ischemic and contusional injuries. In the present study, we used a rat acute SDH model to assess the effect of hypothermia on the intracranial pressure (ICP) and also on the brain edema formation at 4 h after hematoma induction. Mild (34 degrees C) and moderate (32 degrees C) hypothermia did not significantly affect the ICP or cerebral perfusion pressure, but they were associated with a significant lower cortical brain edema formation beneath the hematoma (81.09 +/- 0.49%, p<0.05; and 80.88 +/- 0.17%, p<0.01) when compared with the normothermic control group (81.65 +/- 0.52%). This reduction in brain edema formation was comparable to the results of MK-801 treatment (80.95 +/- 0.35%, p<0.01). The present findings indicate that hypothermia represents a potent neuroprotective strategy. The possible protective mechanisms of hypothermic protection afforded in this rat acute SDH model are discussed.
Animals↗
Antihypertensive effects of a mixed endothelin-A- and -B-receptor antagonist, J-104132, were augmented in the presence of an AT1 -receptor antagonist, MK-954.
The single oral administration of a mixed endothelin-A-and -B- (ETA/ETB) receptor antagonist, J-104132 (L-753,037) decreased the blood pressure in conscious spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP) and Dahl salt-sensitive hypertensive rats fed high-salt diet (DS-H) at doses of 3 and 10 mg/kg, with a duration of approximately 24 h. The magnitude of the antihypertensive effects was greater in DS-H than in SHR and SHRSP Preproendothelin-1 mRNA expression in the kidney and aorta was greater (about twofold) in DS-H than that in nonnotensive Dahl salt-resistant rats fed high-salt diet (DR-H), while there was no difference in preproendothelin-1 mRNA expression between SHR and Wistar Kyoto rats (WKY). An AT1-receptor antagonist, MK-954 (Losartan), also attenuated hypertension in SHR and SHRSP at oral doses of 3 and 10 mg/kg, but bad no effect in DS-H. The concomitant treatment with MK-954 and J-104132 showed additive antihypertensive effects in SHR and SHRSP. In DS-H, MK-954 potentiated the antihypertensive effects of J-104132. From these results, we suggest that: (1) the contribution of endothelin (ET) to the maintenance of hypertension is greater in salt-sensitive hypertensive models than in SHR and SHRSP; (2) the antihypertensive efficacy of ETA/ETB blockade is augmented by AT1-receptor blockade; (3) ET blockers alone or in combination with AT1 antagonists could be useful in the treatment of hypertension for patients who do not respond adequately to renin-angiotensin system inhibitors alone.
Angiotensin Receptor Antagonists↗
Inaudible high-frequency sounds affect brain activity: hypersonic effect.
Although it is generally accepted that humans cannot perceive sounds in the frequency range above 20 kHz, the question of whether the existence of such "inaudible" high-frequency components may affect the acoustic perception of audible sounds remains unanswered. In this study, we used noninvasive physiological measurements of brain responses to provide evidence that sounds containing high-frequency components (HFCs) above the audible range significantly affect the brain activity of listeners. We used the gamelan music of Bali, which is extremely rich in HFCs with a nonstationary structure, as a natural sound source, dividing it into two components: an audible low-frequency component (LFC) below 22 kHz and an HFC above 22 kHz. Brain electrical activity and regional cerebral blood flow (rCBF) were measured as markers of neuronal activity while subjects were exposed to sounds with various combinations of LFCs and HFCs. None of the subjects recognized the HFC as sound when it was presented alone. Nevertheless, the power spectra of the alpha frequency range of the spontaneous electroencephalogram (alpha-EEG) recorded from the occipital region increased with statistical significance when the subjects were exposed to sound containing both an HFC and an LFC, compared with an otherwise identical sound from which the HFC was removed (i.e., LFC alone). In contrast, compared with the baseline, no enhancement of alpha-EEG was evident when either an HFC or an LFC was presented separately. Positron emission tomography measurements revealed that, when an HFC and an LFC were presented together, the rCBF in the brain stem and the left thalamus increased significantly compared with a sound lacking the HFC above 22 kHz but that was otherwise identical. Simultaneous EEG measurements showed that the power of occipital alpha-EEGs correlated significantly with the rCBF in the left thalamus. Psychological evaluation indicated that the subjects felt the sound containing an HFC to be more pleasant than the same sound lacking an HFC. These results suggest the existence of a previously unrecognized response to complex sound containing particular types of high frequencies above the audible range. We term this phenomenon the "hypersonic effect."
Acoustic Stimulation↗
Solitary fibrous tumor of the peritoneum found in the prevesical space.
Solitary fibrous tumors (SFT) are well recognized in the pleura, but their rare occurrence at other sites has become appreciated only in recent years. We experienced a 68-year-old male patient who presented with frequency of urination and difficulty in voiding. Computed tomographic scan revealed a solid and cystic mass which measured 12 x 10 cm in the prevesical space. This tumor showed typical histopathologic features of SFT, and was immunostained positive for vimentin, CD34 and CD99. This is an extremely rare case of SFT arising from the parietal peritoneum found in the prevesical space.
Aged↗
Effects of delayed intraischemic and postischemic hypothermia on a focal model of transient cerebral ischemia in rats.
BACKGROUND AND PURPOSE: Intraischemic mild hypothermia has been shown to be neuroprotective in reducing cerebral infarction in transient focal ischemia. As a more clinical relevant issue, we investigated the effect of delayed intraischemic and postischemic hypothermia on cerebral infarction in a rat model of reversible focal ischemia. We also examined the effect of hypothermia on the inflammatory response after ischemia-reperfusion to assess the neuroprotective mechanism of brain hypothermia. METHODS: Rats were subjected to 2 hours of middle cerebral artery occlusion followed by 22 hours of reperfusion under the following protocols: (1) rats were treated with normothermia (37.0 degrees C, 4 hours) and then housed in room temperature (25 degrees C, 18 hours) and (2) rats were treated with hypothermia (33.0 degrees C, 4 hours, brain temperature modulation was started 30 minutes before the reperfusion) and then housed in cold temperature (5 degrees C, 18 hours). Animals were killed 24 hours after the onset of ischemia. The infarct volume was examined with 2,3,5-triphenyl-tetrazolium chloride staining. The accumulation of polymorphonuclear leukocytes (PMNLs) and the expression of intercellular adhesion molecule-1 mRNA were evaluated in both groups. RESULTS: A significant reduction (P<0.05) in infarct volume was found in the hypothermia group compared with the normothermia group. Compared with the normothermia group, hypothermic treatment also significantly reduced the accumulation of PMNLs (P<0.01) and inhibited the overexpression of intercellular adhesion molecule-1 mRNA at 22 hours of reperfusion after 2 hours of ischemia. CONCLUSIONS: Ischemic brain damage can be reduced with delayed intraischemic and prolonged postischemic hypothermia in a focal model of transient cerebral ischemia in rats. The neuroprotective mechanism of hypothermia may be mediated by suppression of PMNL-mediated inflammatory response after ischemia-reperfusion in this model.
Animals↗
[Model and inference for quantal response pharmacological assay].
A quantal response bioassay is defined as an experiment for estimating the potency of a drug, material or process by means of the reaction (quantal response) that follows its application to living matter. For example, the main object of bioassays in drug development is to measure the potency of some new compounds relative to some standard drug in terms of magnitudes of their effects on responses from living subjects. The quantitative estimates of their potency are summarized by comparing these dose-response curves. In this paper, we focus on analyses intended to compare two dose-response curves with quantal response and consider the model validation and the interpretation of fitting results from a statistical point of view.
Animals↗
Structural features of N-glycans linked to royal jelly glycoproteins: structures of high-mannose type, hybrid type, and biantennary type glycans.
The structures of N-glycans of total glycoproteins in royal jelly have been explored to clarify whether antigenic N-glycans occur in the famous health food. The structural feature of N-glycans linked to glycoproteins in royal jelly was first characterized by immunoblotting with an antiserum against plant complex type N-glycan and lectin-blotting with Con A and WGA. For the detail structural analysis of such N-glycans, the pyridylaminated (PA-) N-glycans were prepared from hydrazinolysates of total glycoproteins in royal jelly and each PA-sugar chain was purified by reverse-phase HPLC and size-fractionation HPLC. Each structure of the PA-sugar chains purified was identified by the combination of two-dimensional PA-sugar chain mapping, ESI-MS and MS/MS analyses, sequential exoglycosidase digestions, and 500 MHz 1H-NMR spectrometry. The immunoblotting and lectinblotting analyses preliminarily suggested the absence of antigenic N-glycan bearing beta1-2 xylosyl and/or alpha1-3 fucosyl residue(s) and occurrence of beta1-4GlcNAc residue in the insect glycoproteins. The detailed structural analysis of N-glycans of total royal jelly glycoproteins revealed that the antigenic N-glycans do not occur but the typical high mannose-type structure (Man(9 to approximately 4)GlcNAc2) occupies 71.6% of total N-glycan, biantennary-type structures (GlcNAc2Man3 GlcNAc2) 8.4%, and hybrid type structure (GlcNAc1 Man4GlcNAc2) 3.0%. Although the complete structures of the remaining 17% N-glycans; C4, (HexNAc3 Hex3HexNAc2: 3.0%), D2 (HexNAc2Hex5HexNAc2: 4.5%), and D3 (HexNAc3Hex4HexNAc2: 9.5%) are still obscure so far, ESI-MS analysis, exoglycosidase digestions by two kinds of beta-N-acetylglucosaminidase, and WGA blotting suggested that these N-glycans might bear a beta1-4 linkage N-acetylglucosaminyl residue.
Blotting, Western↗
Analysis of hepatocellular carcinoma fed by internal thoracic artery
Purpose: The purpose of this study was to elucidate the clinical features of hepatocellular carcinoma (HCC) fed by the internal thoracic artery (ITA). Methods: In seven patients HCC fed by the ITA was confirmed by digital subtraction angiography. The number of previous transcatheter arterial embolization (TAE), the period from the first TAE to TAE of the ITA, tumor location, tumor size, and occlusion of the hepatic artery (HA) and other collateral vessels were explored in each case. Results: The HCCs were located in S4 of the liver (n = 5) and in S8 (n = 1) and were fed by the right ITA and one nodule in S2-3 was fed by the left ITA. Tumor size was 3-10 cm. The number of previous TAE of the HA ranged from 2 to 12. The period from the first TAE to TAE of the ITA was 3-53 months. Angiography of these patients showed occlusion of the HA in six cases, and of the extrahepatic collaterals including the inferior phrenic artery (IPA) in five cases, intercostal artery (ICA) in one case, and epicholedocal artery (EPA) in one case. Conclusion: The ITA often supplies HCC located in the anterior superior region of the liver under the diaphragm; there can be long-term survival with repeated TAE and occlusion of HA.
Journal Article↗
[Regulation of neural network by changes in receptors: overview].
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Adenoviridae↗
[Changes in glutamate receptors after brain ischemia].
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Animals↗
Altered synaptic transmission in the hippocampus of the castrated male mouse is reversed by testosterone replacement.
PURPOSE: To determine the effect of castration on hippocampal function, we have investigated synaptic transmission in the castrated male mouse in vivo. We also examined whether administering testosterone can reverse the changes. MATERIALS AND METHODS: Male 12 weeks-old C57BL/6J mice were divided into three experimental groups; sham-castration (Control), the castration group (Cast), and the castration plus testosterone propionate group (Cast+TP). Field excitatory postsynaptic potentials (fEPSP) were evoked in the CA1 area of the hippocampus by stimulating the commissural fibers of the contralateral hippocampus. Field EPSPs were evoked in the granular cells of the dentate gyrus (DG) by stimulating the ipsilateral perforant path fibers. RESULTS: Laminar analysis of the fEPSPs in the hippocampal CA1 pyramidal cell layer did not differ significantly between the three experimental groups. However, paired pulse facilitation (PPF) of the fEPSP with short inter-stimulus intervals (30 to 100 msec) was significantly suppressed in Cast group. This suppression was reversed by testosterone injection (Cast+TP). Longterm potentiation (LTP) in the CA1 pyramidal neurons by high frequency stimulation (HFS) did not differ significantly between the three experimental groups, whereas potentiation evoked by primed burst stimulation (PBS) was much weaker in the Cast group compared with the Control group. Testosterone injection restored the PBS-induced potentiation to the control level. Synaptic transmission between perforant pathway and the granule cells in the dentate gyrus (DG) did not differ significantly among the three experimental groups. CONCLUSIONS: Suppression of PPF and impairment of the potentiation by PBS in CA1 hippocampal neurons was observed in castrated male mice and these changes were reversed by testosterone injection. These findings suggest that altered synaptic transmission in the castrated male mouse is caused by disturbance of inhibitory neuronal networks that are influenced by testosterone.
Animals↗