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Biomedical subjects

S Kurata

Publications and source records attributed to S Kurata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Ambulatory monitoring of behavior in daily life by accelerometers set at both-near-sides of the joint.

In this paper we examined a new joint motion monitoring method by use of accelerometers to monitor subjects' detailed motion in daily activities. In this method two accelerometers are set at as near points of both sides around the joint as possible. The difference between these two sensors' outputs mainly depend on the joint angle because the centrifugal and the turning acceleration occurred by the rotation around the joint can be neglected. In the experiments we tried to monitor various subject's behaviors of his upper and lower extremities and whole body motion, and could show this method is useful for the ambulatory monitoring of behavior in daily life.

Acceleration↗
PubMed2000

Selective activation of p38 MAPK cascade and mitotic arrest caused by low level oxidative stress.

Apoptosis induced by high level oxidative stress accompanies diverse cellular biochemical events including activation of the stress signal cascades of JNK and NF-kappaB. We report here selective activation of p38 MAPK cascade and mitotic arrest under a low level oxidative stress that lacks apoptosis induction. U937 human lymphoid cells treated with low dose (0.02 mm) H(2)O(2) rapidly caused p38 MAPK cascade activation detectable by phosphorylation of MKK3/6, p38 MAPK, activating transcription factor-2, and cAMP-responsive element-binding protein, leaving the JNK and NF-kappaB cascades unaffected. The p38 kinase activation was sustained for 24 h under the low level stress conditions and led to formation of polyploid nuclei. N-Acetyl-l-cysteine, a precursor of anti-oxidant glutathione, canceled both p38 MAPK activation and abnormal cell cycle progression, whereas blockage of the kinase by specific inhibitor SB203580 allowed the appearance of apoptotic cells. Thus, mimicking the effects of nocodazole, the low level oxidative stimulus caused inhibition of cell division in the M phase through p38 MAPK activation. The kinase cascade may serve as a primary transducer of cytoplasmic oxidative signals to nucleus for stress-relieving gene expression and cell cycle control before apoptosis-inducing signals are transduced. This is the first report demonstrating that oxidative stress can participate in cell cycle control by induction of a signal cascade.

Acetylcysteine↗
PubMed2000

Notch signaling and the determination of appendage identity.

The Notch signaling pathway defines an evolutionarily conserved cell-cell interaction mechanism that throughout development controls the ability of precursor cells to respond to developmental signals. Here we show that Notch signaling regulates the expression of the master control genes eyeless, vestigial, and Distal-less, which in combination with homeotic genes induce the formation of eyes, wings, antennae, and legs. Therefore, Notch is involved in a common regulatory pathway for the determination of the various Drosophila appendages.

Animals↗
PubMed2000

Relationship between cancer cell proliferation and thallium-201 uptake in lung cancer.

UNLABELLED: Although thallium-201 (201Tl) uptake is related to perfusion in many normal tissues, the biologic rationale for 201Tl uptake in tumors is uncertain. To determine if tumor uptake is related to cell proliferation, we correlated the relative retention of 201Tl in lung tumors with expression of Ki-67, an indicator of cell proliferation. METHODS: Sixty patients with lung tumors, included small cell carcinoma (n = 8) and non-small cell carcinoma (n = 52), underwent 201Tl single photon emission computed tomography (SPECT) imaging. The 201Tl lesion uptake was determined on early and delayed images and the radiotracer retention index (RI) was calculated. Tumor specimens were obtained at surgery or bronchoscopy. The cell proliferation ratio was estimated with MIB-1, a monoclonal antibody that recognized the nuclear antigen Ki-67. RESULTS: The average 201Tl index was 2.13+/-0.61 (early) and 2.46+/-0.83 (delayed). The average RI was 17.44+/-35.01. Overall, the 201Tl index (delayed) and the cancer cell proliferation were correlated (r = 0.70, p < 0.0001). Of interest, there was a significant correlation (r = 0.872, p < 0.0005) between the 201Tl index on delayed images and the cell proliferation ratio in patients with small cell but not non-small cell lung carcinoma. The 201Tl index (delayed) was significantly higher (p < 0.0001) in patients with small cell lung carcinoma than in patients with non-small cell lung carcinoma. CONCLUSION: 201Tl imaging appears to be useful for evaluating patients with small cell lung carcinoma but not non-small lung carcinoma, and is correlated with the monoclonal antibody MIB-1, a marker of cell proliferation.

Adult↗
PubMed1999

Transcriptional activation of heme oxygenase-1 gene in mouse spleen, liver and kidney cells after treatment with lipopolysaccharide or hemoglobin.

Heme oxygenase (HO)-1 catalyzes the conversion of heme to biliverdin, iron and carbon monoxide. HO-1 is induced by many reagents including heme, Hb and lipopolysaccharide (LPS). LPS is known to activate the HO-1 gene in cultured mouse liver and macrophage cells through oxidative activation of NF-kappaB. But little is known about the effect of LPS and Hb on the HO-1 gene in living organisms. To study this issue, we examined the HO-1 and its mRNA levels in mouse liver, spleen and kidney after intravenous administration of LPS and Hb. On LPS treatment, the amount of HO-1 and its mRNA increased markedly mainly in mouse spleen, but on Hb treatment the amounts of HO-1 and its mRNA increased slightly only in liver. Run-off transcription assay supported the above results and band shift assays also revealed that LPS significantly activates an NF-kappaB-like factor in spleen cells, while Hb slightly activates it in liver cells. According to our previous study, a small amount of Hb injected to mouse is selectively taken up by liver as Hb-haptoglobin complex. These results suggest different pathways for the HO gene activation in mouse organs; one by LPS in spleen cells and the other by Hb in liver cells.

Animals↗
PubMed1999

The mRNA for protease nexin-1 is expressed in human dermal papilla cells and its level is affected by androgen.

Protease nexin-1, an inhibitor of serine proteases, plays important parts in the regulation of the growth, differentiation, and death of cells by modulating proteolytic activity. The mRNA for protease nexin-1 accumulates in rat dermal papilla cells in a hair cycle-dependent fashion and its levels are well correlated with the ability of dermal papilla cells to support hair growth. In an attempt to characterize the potential role of protease nexin-1 as a modulator of hair growth in humans, we investigated the steady-state level of protease nexin-1 mRNA in cultured human dermal papilla cells using a semiquantitative technique that involved reverse transcription and polymerase chain reaction, as well as the localization of this mRNA in vivo using dissected hair follicles. Protease nexin-1 mRNA was expressed in all dermal papilla cells examined, and it was also identified in the lower part of the connective tissue sheath. Moreover, we found that levels of protease nexin-1 mRNA were depressed by dihydrotestosterone, the most potent androgen, in cultured dermal papilla cells obtained from balding scalp. Our results suggest that protease nexin-1 might be a key molecule in the control of hair growth in humans and, moreover, that the androgen-mediated downregulation of the synthesis of protease nexin-1 might be associated with the progression of male-pattern baldness.

Adult↗
PubMed1999

Viability of isolated single hair follicles preserved at 4 degrees C.

BACKGROUND: Hair follicle preservation for the purpose of delayed application would help us to transplant hair follicles more efficiently. METHODS: Isolated single hair follicles were preserved at 4 degrees C in four different solutions. Viability of preserved follicles was judged by organ culture and cell culture. In addition, a small number of hair follicles were transplanted into athymic mice. RESULTS. By cell culture, both dermal papilla and outer root sheath cells could be cultivated after 7 days of preservation. Hair follicles preserved for 48 hours showed a significant increase of hair shafts in organ culture. Those preserved for 7 days regrew well when transplanted into athymic mice. CONCLUSION: Preservation of hair follicles at 4 degrees C could be one option to prepare many follicular units at one time for transplantation.

Adult↗
PubMed1999

Invasion of the lacrimal system by basal cell carcinoma.

BACKGROUND: The rate of recurrence of basal cell carcinoma (BCC) in the periorbital region is higher than that in other areas because of the spread of the tumor along barrier structures. OBJECTIVE: A better understanding of the biological behavior of BCC in this area, in particular as it relates to the lacrimal system, should improve the outcome of surgery. METHODS: A study was made of two cases of BCC that developed in the periorbital region and invaded the lacrimal system. RESULTS: The tumors were found to have invaded the lacrimal system along the mucosal epithelium. Magnetic resonance imaging (MRI) did not suggest any abnormalities in this area. In one patient, the tumor had infiltrated the nasal cavity without destruction of the periorbital bone and nasal cartilage. A preoperative fiberscopic examination clearly demonstrated the involvement of the nasal cavity in this case. CONCLUSION: The lacrimal system is often invaded by BCC that originates from the periorbital region. Physicians and surgeons need to be well aware of the possibility of such aggressive infiltration by BCC.

Aged↗
PubMed1999

Two subunits of the insect 26/29-kDa proteinase are probably derived from a common precursor protein.

We previously identified the 26/29-kDa proteinase in the hemocytes of Sarcophaga peregrina (flesh fly) that appears to participate in elimination of foreign proteins in this insect [Eur. J. Biochem. 209, 939-944 (1992)]. Here, we report the cDNA cloning of this proteinase. The cDNA encodes a protein which includes both the 26- and 29-kDa subunit, strongly suggesting that the both subunits are derived from a single precursor protein. The 26- and 29-kDa subunit located at the amino-terminal and carboxyl-terminal of the precursor protein. The 29-kDa subunit itself appeared to be a proteinase, for this subunit had 52% sequence identity with Sarcophaga cathepsin L, while 26-kDa subunit had no significant similarity. We also showed that 26/29-kDa proteinase was insensitive to specific inhibitors of cathepsin L. These results indicate that this proteinase is a novel member of the papain family. We isolated similar cDNAs from Drosophila melanogaster and Periplaneta americana (cockroach), suggesting that this proteinase is conserved in a wide variety of insects and participates in their defense mechanisms.

Amino Acid Sequence↗
PubMed1999

Enhancement by arginine vasopressin of the L-type Ca2+ current in guinea pig ventricular myocytes.

Effects of arginine-vasopressin (AVP) on the cardiac L-type Ca2+ current (ICa,L) were investigated in single ventricular cells of guinea pig hearts by the conventional and nystatin-perforated patch clamp methods. Using the conventional whole-cell clamp method, AVP (0.01-1 micromol/l) appeared to have little effect on ICa,L, but the same concentrations of AVP consistently increased ICa,L using the nystatin-perforated patch clamp mode. The stimulatory effect was blocked by either OPC-21268 (8 micromol/l), a selective V1 receptor antagonist, or staurosporine (10 nmol/l), an inhibitor of protein kinases. AVP further increased the amplitude of ICa,L previously augmented maximally by isoprenaline (1 micromol/l). When myocytes were pretreated with ryanodine (2 micromol/l) or cyclopiazonic acid (3 micromol/l), the increase in ICa,L by AVP was partially reduced. The present results indicate that protein kinase C might be involved in the AVP-induced increase of ICa,L. The AVP-induced increase in ICa,L may require intracellular constituents, which might be washed out during the use of the conventional whole-cell patch clamp method.

Animals↗
PubMed1998

A novel lectin from Sarcophaga. Its purification, characterization, and cDNA cloning.

A novel C-type lectin that agglutinates rabbit red cells was purified from NIH-Sape-4 cells derived from the flesh fly (Sarcophaga peregrina), and its cDNA was isolated. This lectin, named granulocytin, appeared to be a trimer of a 20-kDa subunit consisting of 151 amino acid residues. The gene for granulocytin was activated in third instar larvae, and its expression was enhanced when the larval body wall was injured. In third instar larvae, granulocytin was found to be synthesized by hemocytes and secreted into the hemolymph. The molecular mass and gene expression patterns of granulocytin were very similar to those of Drosophila lectin that we reported previously (Haq, S., Kubo, T., Kurata, S., Kobayashi, A., and Natori, S. (1996) J. Biol. Chem. 271, 20213-20218). However, these two lectins showed amino acid identities of 20% at most, and no significant hapten sugar for granulocytin was identified.

Adipose Tissue↗
PubMed1998

Surgery for abdominal aortic aneurysms associated with malignancy.

Of 148 patients treated for abdominal aortic aneurysms (AAA), 33 (22%) also had cancer. According to the classification of Szilagyi, there were 13 patients in group I, 19 in group II, and 1 in group IV. In group I, the mean interval between the cancer and AAA operations was 7 years (range 1-14 years). Aneurysmectomy was performed in 9 patients, wrapping in 2, and no operation in 2. In group II, a two-stage operation was performed in 8 patients, a single-stage operation in 4, only surgery for cancer in 4, and no operation in 3. Of 4 patients undergoing single-stage operations, 3 had colorectal cancer, and there were no postoperative complications such as graft infection or anastomotic breakdown. In group I, 6 of 13 patients died, but there were no cancer deaths. In group II, 9 of 19 patients died, 6 from progressive cancer. The group IV patient also died of cancer. These results suggest that if a patient can tolerate surgery for both diseases, a single-stage operation is preferable.

Abdominal Neoplasms↗
PubMed1998

Ambulatory physical activity monitoring system.

In this study, we have developed an ambulatory behaviour map and physical activity monitoring system by equipping our portable digital biosignal memory device developed previously with a GPS sensor and piezoresistive accelerometers. By this system, we can get the subjects behaviour map, his physical activities and posture changes in daily life.

Behavior↗
PubMed1997

Identification of gamma-aminobutyric acid-immunoreactive axon endings associated with mesencephalic periodontal afferent terminals and morphometry of the two types of terminals in the cat supratrigeminal nucleus.

A previous study has shown that mesencephalic periodontal afferent terminals receive contacts more frequently from axonal endings containing pleomorphic, synaptic vesicles (P-endings) in the supratrigeminal nucleus (Vsup) than in the trigeminal motor nucleus, suggesting that interneurons in Vsup play an important role in modulating the jaw-closing reflex. The present study was attempted to identify neurotransmitters in P-endings associated with mesencephalic periodontal afferents in cat Vsup through the use of intracellular staining of horseradish peroxidase combined with the postembedding immunogold methods. A morphometric analysis was carried out to compare the ultrastructural features of these two types of terminals. Serial sections of 31 labeled boutons and of their associated 38 P-endings were examined. They were processed for postembedding immunogold labeling with antibodies to the neurotransmitter gamma-aminobutyric acid (GABA). The 38 P-endings presynaptic to periodontal afferents showed GABA-like immunoreactivity, but the afferent terminals were free from the labeling. The morphometric analysis indicated that bouton volume, apposed surface area, total active zone size, and mitochondrial volume were smaller in GABA-immunoreactive P-endings than in periodontal afferents, but the pooled data of the two types of terminals showed that each synaptic parameter was highly correlated in a positive, linear manner with bouton volume. These observations provide evidence that P-endings presynaptic to mesencephalic periodontal afferents contain the neurotransmitter GABA and that their axoaxonic synapses are organized in accordance with the ultrastructural "size principle" proposed by Pierce and Mendell (Pierce and Mendell [1993] J. Neurosci. 13:4748-4763) on Ia-motoneuron synapses.

Animals↗
PubMed1997

Ultrastructural observations of synaptic connections of vibrissa afferent terminals in cat principal sensory nucleus and morphometry of related synaptic elements.

Previous work suggests that slowly adapting (SA) periodontal afferents have different synaptic arrangements in the principal (Vp) and oral trigeminal nuclei and that the synaptic structure associated with transmitter release may be related directly to bouton size. The present study examined the ultrastructures of SA and fast adapting (FA) vibrissa afferents and their associated unlabeled axonal endings in the cat Vp by using intra-axonal labeling with horseradish peroxidase and a morphometric analysis. All SA and FA afferent boutons contained clear, round, synaptic vesicles. All the FA and most SA boutons were presynaptic to dendrites, but a few SA boutons were axosomatic. Both types of bouton were frequently postsynaptic to unlabeled axonal ending(s) containing pleomorphic, synaptic vesicles (P-ending). The size of labeled boutons was larger in FA than SA afferents, but the size of dendrites postsynaptic to labeled boutons was larger for SA than FA afferents. Large-sized FA and SA boutons made synaptic contacts with small-diameter dendrites. The size of FA and SA boutons was larger than that of their associated P-endings. A morphometric analysis made on the pooled data of SA and FA boutons indicated that apposed surface area, active zone number, total active zone area, vesicle number, and mitochondrial volume were highly correlated in a positive linear manner with labeled bouton volume. These relationships were also applicable to unlabeled P-endings, but the range of each parameter was smaller than that of the labeled boutons. These observations provide evidence that the two functionally distinct types of vibrissa afferent manifest unique differences but share certain structural features in the synaptic organization and that the ultrastructural "size principle" proposed by Pierce and Mendell ([1993] J. Neurosci. 13:4748-4763) for Ia-motoneuron synapses is applicable to the somatosensory system.

Adaptation, Physiological↗
PubMed1997

Purification and characterisation of cathepsin B mRNA 3'-untranslated-region-binding protein (CBBP), a protein that represses cathepsin B mRNA translation.

We reported that the 3'-untranslated region (3'-UTR) of cathepsin B mRNA of Sarcophaga peregrina (flesh fly) is necessary for the repression of its translation, and detected the 3'-UTR-binding protein in lysates of larval hemocytes in which cathepsin B mRNA translation was repressed [Yano, T., Kurata, S. & Natori, S. (1995) Eur. J. Biochem. 234, 39-43]. In this study, we purified the 3'-UTR-binding protein from an embryonic cell line of Sarcophaga. The purified protein (CBBP) was found to repress cathepsin B mRNA translation in a rabbit reticulocyte lysate. We found that the CBBP contents of the hemocytes did not change during metamorphosis, although the cathepsin B mRNA became translatable only at the pupal stage. Moreover, we found that pupal, but not larval hemocytes, contained a factor that inhibited the binding of CBBP to the 3'-UTR. A regulatory mechanism of cathepsin B expression in Sarcophaga hemocytes is discussed.

Animals↗