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Biomedical subjects

K Kanemaru

Publications and source records attributed to K Kanemaru.

At least 19 recordsLinked to original sources
PubMed2001

NdWFamide: a novel excitatory peptide involved in cardiovascular regulation of Aplysia.

Although diverse peptides are known to affect invertebrate cardiac activity, the peptidergic regulation of the cardiovascular system of Aplysia is still poorly understood. Asn-D-Trp-Phe-NH(2) (NdWFamide) is a recently purified cardioactive peptide in Aplysia. Pharmacological experiments showed that NdWFamide was one of the most potent cardioexcitatory peptides among the known endogenous cardioactive peptides in Aplysia. NdWFamide-immunopositive neuronal processes were abundant in the cardiovascular region of Aplysia, and many of them originated from neurosecretory cells in the abdominal ganglion (R3-R13 cells). The data suggest that NdWFamide is a cardioexcitatory peptide utilized by R3-R13 cells of Aplysia.

Animals↗
PubMed2001

The effects of short-term blood pressure variability and nighttime blood pressure levels on cognitive function.

We investigated the relationship between 24-h blood pressure (BP) and cognitive function. We performed the Hasegawa Dementia Scale Revised (HDSR), the Mini-Mental State Examination (MMSE), and the Raven's Coloured Progressive Matrices Test (RCPM) in 88 subjects (71+/-9 years) with no history of stroke. Ambulatory BP was non-invasively measured using a TM2421 for 24 h in all patients. Whereas 90% of the scores converged into a narrow range between 25 and 30 points in the HDSR and the MMSE tests, the RCPM score was widely distributed, ranging from 9 to 36 points. The subjects were therefore divided into three groups of > or =25, 26-30, and 31-36 according to their RCPM scores. Subjects with lower scores were significantly associated with increased short-term BP variability during the daytime (p<0.05) and had a tendency toward higher nighttime SBP (p=0.05) compared with those with higher scores. Increased short-term variability of daytime BP and high nighttime systolic BP were associated with cognitive impairment as assessed by the RCPM. The RCPM, which can assess the capacity for judgment through visual information processing, may detect earlier stages of cognitive impairment related to high BP. To prevent a deterioration of cognitive function, strict control of nighttime BP and suppression of short-term BP variability are thus necessary.

Aged↗
PubMed2001

[Quantitative evaluation of the burden of those giving home care for senile dementia of Alzheimer type subjects using the burnout scale of pines].

We quantitatively measured the physical and psychological burden of caregivers of 25 patients with senile dementia of Alzheimer type (SDAT). The Barthel Index (BADL, full score: 20 points) and the caregiver burden in terms of physical symptoms correlated well (r = -0.964, p < 0.001), as did the degree of abnormal behavior and caregiver burden in terms of psychological symptoms (r = 0.946, p < 0.001). The correlation with the burnout scale (BOS) of Pines was best when both factors of psychological and physical symptoms were included. The correlation between BOS and the caregiver burden in terms of both physical and psychological symptoms was r = 0.874, p < 0.001, and the correlation between BOS and "the degree of abnormal behavior" +(20- "BADL") was r = 0.853, p < 0.001. The burden in terms of physical symptoms increased as the BADL score decreased, but the burden in terms of psychological symptoms increased initially and decreased in the last phase of the disease. We conclude that the BOS score of SDAT caregivers was stable in the initial phase, then increased rapidly, thereafter preserved high, and dropped rapidly as the BADL score decreased.

Activities of Daily Living↗
PubMed2001

[Antihypertensive therapy in patients with stroke].

Most patients with acute ischemic stroke do not need antihypertensive therapy, because the rapid lowering of blood pressure (BP) may reduce cerebral blood flow due to impaired cerebral autoregulation. In patients with severe hypertension, or associated with other complications (hemorrhagic transformation, myocardial infarction, renal failure or dissection of the aorta), antihypertensive therapy should be done cautiously. In chronic phase, the optimal BP level for the prevention of stroke recurrence remains unclear. The presence of the J-curve phenomenon is still controversial. The several large scale trials are now in progress to determine the optimal BP level for the secondary prevention in stroke patients.

Antihypertensive Agents↗
PubMed2000

Tri-n-butyltin-induced change in cellular level of glutathione in rat thymocytes: a flow cytometric study.

Since some of organotins, accumulated in edible mollusks of aquatic environments, exert a variety of toxic actions on experimental animals, it causes concern for the health of humans. We examined the effects of tri-n-butyltin chloride (TBT) and other organotins (triethyltin chloride, trimethyltin chloride, triphenyltin chloride and tetrabutyltin) on cellular content of glutathione (GSH) in rat thymocytes using a flow cytometer to further characterize the toxicity of TBT. When the cells were incubated with TBT at concentrations of 3 nM or more for 15 min, the cellular content of GSH dose-dependently decreased. However, it completely or partly recovered until 180 min even in the continued presence of TBT. This recovery was temperature-sensitive, suggesting an involvement of metabolic process. The efficacy of TBT to decrease the cellular content of GSH was greater than those of other organotins. Results suggest that TBT and some organotins at environmentally relevant (nanomolar) concentrations significantly reduce the cellular content of GSH, suggesting that they increase the vulnerability to some biological and chemical insults.

Animals↗
PubMed2000

Impairment and restoration of the endothelial blood-brain barrier in the rat cerebral infarction model assessed by expression of endothelial barrier antigen immunoreactivity.

Endothelial barrier antigen (EBA) can be used to detect the blood-brain barrier in the central nervous system of rats. This study investigated the temporal profile of antigen expression in cerebral vessels after infarction and assessed the relationship between re-establishment of this antigen in newly formed vessels and astrocytes around these vessels. Rats were subjected to cerebral ischemia for 2 h by the intraluminal thread method, then killed after 1, 3, 7, 14 and 28 days. Perfusion-fixed paraffin-embedded brains were immunostained for detection of EBA and glial fibrillary acidic protein (GFAP) by the streptavidin-biotin-peroxidase complex method. EBA immunostaining in vessels in the infarcted lesion was reduced at day 1 and had almost disappeared by day 3. Newly formed vessels were found from day 3, but were not stained at day 7. However, these new vessels were weakly stained at day 14 and definitely stained at day 28. GFAP immunostaining was completely negative around these proliferating vessels. The temporal profile of disappearance and re-expression of EBA in cerebral infarcted lesion may be associated with aggravation and improvement of brain edema, although barrier permeability was not explored in this study. The expression of this antigen has no relationship to the formation of astrocyte/endothelial contacts.

Animals↗
PubMed1999

Exposure of rat thymocytes to hydrogen peroxide increases annexin V binding to membranes: inhibitory actions of deferoxamine and quercetin.

Effects of hydrogen peroxide (H(2)O(2)) on rat thymocytes were examined, using a flow cytometer and three fluorescent probes, annexin V-fluorescein isothiocyanate (annexin V-FITC) for detecting phosphatidylserine expressed on the membrane surface, ethidium bromide for estimating dead cells, and fluo-3-acetoxymethyl ester (fluo-3-AM) for monitoring changes in intracellular Ca(2+) concentration ([Ca(2+)](i)), to characterize H(2)O(2)-induced cytotoxicity. Exposure to H(2)O(2) (30 microM or more) increased the number of annexin V-positive live cells dose- and time-dependently while the number of dead cells increased at concentrations of 1 mM or more. H(2)O(2) (30 microM or more) increased [Ca(2+)](i) in a dose-dependent manner. Threshold concentration of H(2)O(2) to increase [Ca(2+)](i) was similar to that to increase annexin V binding to membranes. The H(2)O(2)-induced change in cell membranes was attenuated under Ca(2+)-free conditions. Therefore, it is likely that Ca(2+) is involved in the H(2)O(2)-induced cytotoxicity. Deferoxamine was effective to protect the cells suffering from H(2)O(2)-induced oxidative stress, suggesting a contribution of hydroxyl radicals generated by the Fenton reaction. Quercetin also exerted a potent protective action on cells suffering from H(2)O(2)-induced oxidative stress. The results indicate that the exposure of rat thymocytes to H(2)O(2) at micromolar concentrations increases annexin V binding to cell membranes in a Ca(2+)-dependent manner, suggesting the possibility that the oxidative stress caused by H(2)O(2) (and/or hydroxyl radicals) induces apoptosis via increasing [Ca(2+)](i).

Animals↗
PubMed1999

Biochemical and physiological properties of pedicellarial lectins from the toxopneustid sea urchins.

Pedicellarial lectins (SUL-I, SUL-II, and TGL-I) were purified from the toxopneustid sea urchins, Toxopneustes pileolus and Tripneustes gratilla using gel filtration chromatography, affinity chromatography, and reverse-phase HPLC. SUL-I (Nakagawa et al., 1996) and SUL-II from the large globiferous pedicellariae of T. pileolus are D-galactose-binding lectins with molecular masses of 32 kDa and 23 kDa, respectively; while TGL-I from the globiferous pedicellariae of T. gratilla is a Ca(2+)-independent heparin-binding lectin with a molecular mass of 23 kDa. SUL-I induced mitogenic stimulation on murine splenocytes but TGL-I did not. At higher dose ranges SUL-I exhibited inhibitory effects on the cells. The dual response to SUL-I was effectively inhibited by D-galactose. SUL-I enhanced norepinephrine-induced contraction of isolated rat mesenteric artery with endothelium. When endothelium was removed from the artery, acetylcholine did not relax the norepinephrine-induced contraction. In the same artery the enhancing effect of the contraction by SUL-I was abolished, suggesting that SUL-I acts on the endothelium of mesenteric artery, and may release prostanoids. The present results suggest an extracellular function for SUL-I that may have wide-ranging effects in physiological processes. The primary role of pedicellarial lectins from T. pileolus and T. gratilla might be defense against a foreign body.

Agglutination↗
PubMed1998

Cerebrospinal fluid homovanillic acid levels are not reduced in early corticobasal degeneration.

To investigate the contribution of nigral degeneration to the development of parkinsonism in the early stages of corticobasal degeneration (CBD), we measured the cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) in patients with early CBD (n = 5), and compared the levels with those in patients with early Parkinson's disease (n = 11) and in normal subjects (n = 13). The mean CSF HVA level in the early CBD group (33.1 +/- 6.0 ng/ml) did not differ significantly from that in the control group (37.1 +/- 12.7 ng/ml), whereas that in the early Parkinson's disease group (19.0 +/- 7.6 ng/ml) was reduced significantly (P < 0.001). This result suggests that neuronal cell loss in the substantia nigra and presynaptic nigrostriatal dopaminergic neuron dysfunction are mild in the early stages of CBD.

Aged↗
PubMed1998

Cytotoxic actions of FTY720, a novel immunosuppressant, on thymocytes and brain neurons dissociated from the rat.

Effects of FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol HCl), a novel immunosuppressant, were examined on neurons and thymocytes respectively dissociated from rat brains and thymus glands using a flow cytometer to see if FTY720 exerts cytotoxic actions not only on spleen cells as previously reported but also on the other cells. FTY720 at a concentration of 10 microM deteriorated almost all of the thymocytes, while it was not the case for brain neurons. FTY720 increased the intracellular concentration of Ca2+ ([Ca2+]i) of thymocytes in both the presence and absence of external Ca2+, although the [Ca2+]i increased by FTY720 in the presence of external Ca2+ was much greater than that in the absence of external Ca2+. Thus, FTY720 may increase the membrane permeability of Ca2+ and release Ca2+ from intracellular Ca2+ stores in thymocytes. Furthermore, the number of thymocytes stained with ethidium, a dye impermeant to intact membranes, time-dependently increased after drug application. Therefore, FTY720 at concentrations of 3 - 10 microM non-specifically increases the membrane permeability of thymocytes, resulting in necrotic cell death, although FTY720 at micromolar concentrations was reported to induce apoptosis of spleen cells.

Animals↗
PubMed1997

[Familial parkinsonism: different clinical phenotype between a mother and her daughter].

We reported a familial case of parkinsonism in which clinical features are different between a mother and her daughter. The mother developed rigidity and bradykinesia at age 76. Her symptoms were slowly progressive, and were responsive to levodopa. Thus, she was diagnosed as having Parkinson's disease. In contrast, her daughter developed postural instability as well as rigidity and bradykinesia at age 53 in rapid progression. In addition, she also developed pyramidal signs and autonomic failures, including orthostatic hypotension and urinary incontinence. The disease phenotype of the daughter resembled that of striatonigral degeneration (SND). However, PET studies showed normal binding of 11C-N-methyl-spiperone (NMSP) in the striatum, suggesting that the daughter was also affected with Parkinson's disease.

Aged↗
PubMed1997

[Gait disturbance without motor and sensory involvement in cervical myelopathy--clinical course and radiological findings].

Among 100 patients with cervical myelopathy, we found 7 patients with gait disturbance in which motor or sensory involvements were absent (group A). In these patients, the gait was unsteady, but not ataxic nor spastic. Some of them showed mild hyperreflexia, but no one had Romberg's sign. We compared the effect of neck traction and radiological findings in group A with these in 25 patients who had gait disorders as well as other symptoms associated with cervical myelopathy (group B). Mean age in group A (mean 83.9 +/- 7.9 ys) was older than that in group B (mean 76.6 +/- 5.7 ys). Gait disorders improved in 6 cases of group A (86%), and 5 cases in group B (20%) by conservative therapy of Glisson's traction. On plain X-ray examination, the physiologic lordosis of cervical spine was preserved, the cervical canal diameters from C2 to C7 were more wide, and the number of intervertebral excessive mobility had tendency to be less in group A than in group B. Cervical MRI indicated that the number of intervertebral spinal compression was less in group A than in group B. In the cervical myelopathy, there was a type showing only gait disturbance which was characterized by the good response to Glisson's neck traction, and by the preserved physiological lordosis, relatively wide spinal canal, and slight intervertebral compression.

Aged↗
PubMed1996

Comparable amyloid beta-protein (A beta) 42(43) and A beta 40 deposition in the aged monkey brain.

Two distinct species of amyloid beta-protein (A beta), A beta 42(43) and A beta 40, are deposited in the brains of patients with Alzheimer's disease and normal aged individuals. A beta 42(43), the long tailed A beta, is the initially and predominantly deposited species in senile plaques. Deposition of A beta is also observed in the aged monkey brains. We investigated the A beta species in the aged monkey brains immunocytochemically using monoclonal antibodies that discriminate between the C-termini of A beta 42(43) and A beta 40. We report here that A beta 40 as well as A beta 42(43) deposit in various types of senile plaques, including diffuse plaques of the aged monkey brain and that the ratio of A beta 40 to A beta 42(43) is higher compared with that in human brain.

Aging↗
PubMed1996

Ginkgo biloba extract protects brain neurons against oxidative stress induced by hydrogen peroxide.

Effect of Ginkgo biloba extract was examined on dissociated rat cerebellar neurons suffering from oxidative stress induced by hydrogen peroxide using a flow cytometer and ethidium bromide. Hydrogen peroxide at a concentration of 3 mM increased the number of neurons stained with ethidium (presumably dead neurons) in a time-dependent manner. Pretreatment of neurons with G. biloba extract (10 micrograms/ml) greatly delayed a time-dependent increase in number of dead neurons during exposure to hydrogen peroxide. It was true, but less effective, in the case of treatment with G. biloba extract immediately or 60 min after start of oxidative stress. Results implicate G. biloba extract as a potential agent in protecting the neurons suffering from oxidative stress induced by hydrogen peroxide.

Animals↗
PubMed1996

Flow cytometric analysis of the H2O2-induced increase in intracellular Ca2+ concentration of rat thymocytes.

The effect of hydrogen peroxide (H2O2) on the intracellular Ca2+ concentration ([Ca2+]i) of rat thymocytes was examined by a flow cytometer and two fluorescent dyes, fluo-3-AM and ethidium bromide, a dye impermeant to intact membranes, to characterize the H2O2-induced increase in [Ca2+]i. H2O2 at concentrations greater than 30 microM dose-dependently increased the [Ca2+]i of thymocytes which were not stained with ethidium. Removal of external Ca2+ greatly reduced the degree of H2O2-induced increase in [Ca2+]i. However, H2O2 still increased the [Ca2+]i under the external Ca(2+)-free condition. Diethylmaleate, which is known to produce a chemical depletion of cellular nonprotein thiol, significantly increased the [Ca2+]i. Dithiothreitol, which is used to protect cellular nonprotein thiol, slightly decreased the [Ca2+]i, but greatly reduced the H2O2-induced increase in [Ca2+]i. Therefore, it is considered that H2O2 may increase the [Ca2+]i through a mechanism related to the effects of H2O2 on the cellular nonprotein thiol.

Aniline Compounds↗