Biomedical subjects

Y Uchiyama

Publications and source records attributed to Y Uchiyama.

At least 55 records · Page 3Linked to original sources

PubMed2001

Effects of sodium hyaluronate on epithelial healing of the vesical mucosa and vesical fibrosis in rabbits with acetic acid induced cystitis.

PURPOSE: To evaluate the effect of sodium hyaluronate on epithelial healing of the vesical mucosa and vesical fibrosis, and clarify the effect of the sodium hyaluronate solution concentration, we administered sodium hyaluronate in the bladder of rabbits with acetic acid induced cystitis. MATERIALS AND METHODS: Sodium hyaluronate at 3 concentrations (0.1%, 0.2% and 0.4%) was injected intravesically into rabbits with cystitis. Seven days after injection the effect of sodium hyaluronate was evaluated by bladder capacity measurement. Furthermore, the epithelial defective region of the mucosal membrane and bladder dry weight were determined and the condition of the epithelial membrane and extent of fibrosis were examined histologically. RESULTS: In all sodium hyaluronate treated groups a significant improvement in bladder capacity was observed compared to controls. In addition, a significant reduction was noted in the area of the epithelial defective region in the groups treated with 0.2% or 0.4% sodium hyaluronate and a significant decrease was noted in bladder dry weight in the group treated with 0.4% sodium hyaluronate. Histological examination revealed accelerated epithelial healing of the vesical mucosa and inhibited vesical fibrosis in the group treated with 0.4% sodium hyaluronate. CONCLUSIONS: Our findings suggest that sodium hyaluronate is effective for promoting epithelial healing of the vesical mucosa and inhibiting vesical fibrosis.

Acetic Acid↗

PubMed2001

[Experimental study of pharmacological hypothermia: enhanced neuroprotective effect of a novel 5-HT 1 A agonist SUN N4057 by the pharmacological hypothermia].

PURPOSE: 5-hydroxytryptamine(5-HT) 1 A receptor agonists have a potentially marked neuroprotective reaction by both neuroprotective and hypothermic effects. We previously reported (1) the neuroprotective effect against the cerebral ischemia under normothermic condition, and (2) the hypothermic effect of the novel compound of 5-HT 1 A agonist, SUN N4057. The present investigation was designed to examine the enhancement of the neuroprotective effect by its pharmacological hypothermia. METHODS: In 24 anesthetized cats(body weight 1.9-4.6 kg), the left middle cerebral artery(MCA) occlusion was performed via the transorbital approach. Just after MCA occlusion, SUN N4057(6 micrograms/kg/min) was infused. Physiological parameters were measured continuously, and arterial blood gas was analyzed hourly for 6 hours and maintained within the normal ranges. Animals were randomly allocated to the following three groups: (1) ischemic controls infused with sterile saline(Group A, n = 8), (2) SUN N4057 under normothermic condition(Group B, n = 8), (3) SUN N4057 (Group C, n = 8). Then, brain coronal sections of 3 mm in thickness were stained with 1% triphenyltetrazolium chloride(TTC) solution, and hemispheric infarct volumes were calculated by using a computerized image analysis system. RESULTS: There were no significant differences in any physiological parameters among 3 groups. In Group C, brain temperature decreased significantly starting 1 hour after MCA occlusion and dropped by 2.1 +/- 0.7 degrees C 5 hours. Infarct volumes were 35.6 +/- 6.9% (Group A), 23.3 +/- 5.8% (Group B) and 12.3 +/- 11.3% (Group C), respectively. There were significant differences among three groups(p < 0.05). CONCLUSION: On the basis of these data, we conclude that SUN N4057 provides more effective neuroprotection by the combination of hypothermic and neuroprotective effects. Chemical hypothermia may lead to a new therapeutic approaches for treatment of brain ischemia.

Animals↗

PubMed2001

[A case of atropine-resistant bradycardia in a patient on long-term lithium medication].

A 44-year-old woman was scheduled for laparoscopic cholecystectomy and partial thyroidectomy. She had received lithium, 400-1200 mg daily, and other antidepressants for 10 years for her depressive disorder. Preoperative examination revealed a swelling of the right thyroid associated with hypothyroidism. Her heart rate was in the range of 45-70 min-1 preoperatively. After induction of anesthesia with propofol 50 mg, and fentanyl 100 micrograms, heart rate decreased to 36 min-1 and remained low after tracheal intubation. Atropine sulfate 1.1 mg in divided doses, and ephedrine 4 mg i.v. did not change the heart rate. However, a bolus of isoproterenol 0.02 mg i.v. increased the heart rate to 95 min-1. We suspect that atropine-resistant bradycardia was due to sinus node dysfunction produced by interaction of chronic lithium treatment, fentanyl and propofol. Therefore, an intractable sinus node dysfunction may occur in a patient in whom lithium is given chronically, particularly in whom hypothyroidism is associated. In such a patient, a beta-adrenergic stimulant may be effective in treating bradycardia.

Adult↗

PubMed2000

Necrotic death pathway in Fas receptor signaling.

A caspase 8-deficient subline (JB6) of human Jurkat cells can be killed by the oligomerization of Fas-associated protein with death domain (FADD). This cell death process is not accompanied by caspase activation, but by necrotic morphological changes. Here, we show that the death effector domain of FADD is responsible for the FADD-mediated necrotic pathway. This process was accompanied by a loss of mitochondrial transmembrane potential (DeltaPsim), but not by the release of cytochrome c from mitochondria. Pyrrolidine dithiocarbamate, a metal chelator and antioxidant, efficiently inhibited the FADD-induced reduction of DeltaPsim and necrotic cell death. When human Jurkat, or its transformants, expressing mouse Fas were treated with Fas ligand or anti-mouse Fas antibodies, the cells died, showing characteristics of apoptosis. A broad caspase inhibitor (z-VAD-fmk) blocked the apoptotic morphological changes and the release of cytochrome c. However, the cells still died, and this cell death process was accompanied by a strong reduction in DeltaPsim, as well as necrotic morphological changes. The presence of z-VAD-fmk and pyrrolidine dithiocarbamate together blocked cell death, suggesting that both apoptotic and necrotic pathways can be activated through the Fas death receptor.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Cathepsin D deficiency induces lysosomal storage with ceroid lipofuscin in mouse CNS neurons.

Cathepsin D-deficient (CD-/-) mice have been shown to manifest seizures and become blind near the terminal stage [approximately postnatal day (P) 26]. We therefore examined the morphological, immunocytochemical, and biochemical features of CNS tissues of these mice. By electron microscopy, autophagosome/autolysosome-like bodies containing part of the cytoplasm, granular osmiophilic deposits, and fingerprint profiles were demonstrated in the neuronal perikarya of CD-/- mouse brains after P20. Autophagosomes and granular osmiophilic deposits were detected in neurons at P0 but were few in number, whereas they increased in the neuronal perikarya within days after birth. Some large-sized neurons having autophagosome/autolysosome-like bodies in the perikarya appeared in the CNS tissues, especially in the thalamic region and the cerebral cortex, at P17. These lysosomal bodies occupied the perikarya of almost all neurons in CD-/- mouse brains obtained from P23 until the terminal stage. Because these neurons exhibited autofluorescence, it was considered that ceroid lipofuscin may accumulate in lysosomal structures of CD-/- neurons. Subunit c of mitochondrial ATP synthase was found to accumulate in the lysosomes of neurons, although the activity of tripeptidyl peptidase-I significantly increased in the brain. Moreover, neurons near the terminal stage were often shrunken and possessed irregular nuclei through which small dense chromatin masses were scattered. These results suggest that the CNS neurons in CD-/- mice show a new form of lysosomal accumulation disease with a phenotype resembling neuronal ceroid lipofuscinosis.

Action Potentials↗

PubMed2000

Detection of caspase-9 activation in the cell death of the Bcl-x-deficient mouse embryo nervous system by cleavage sites-directed antisera.

Caspases, which play crucial roles during apoptosis, are activated from their inactive proforms in a sequential cascade of cleavage by other members of the caspase family. Caspase-9 is autoprocessed by the Apaf-1/cytochrome c pathway and acts at an early point in this cascade, whereas Bcl-xL, an antiapoptotic member of the Bcl-2 family, prevents activation of caspases in vitro. Little is known, however, about the relation between caspase-9 and Bcl-xL during development of the mammalian nervous system. We used antisera against two cleavage sites in mouse caspase-9 that recognize only the activated form of mouse caspase-9, and we examined immunohistochemically the activation of mouse caspase-9 in the nervous system of Bcl-x-deficient mouse embryos. Mouse caspase-9 is processed at both D(353) and D(368), but it is processed preferentially at D(368) during apoptosis of cultured cells induced by various stimuli and in the nervous system of Bcl-x-deficient mouse embryos. We show that Bcl-xL protects against caspase-9- and/or caspase-3-dependent apoptosis in the caudal portion of the ventral hindbrain, anterior horn cells, and dorsal root ganglia neurons of the normal mouse embryos and against caspase-9/caspase-3-independent apoptosis in the dorsal region of the nervous system including the dorsal spinal cord. Furthermore, we demonstrate that Bcl-xL blocks cytochrome c release from mitochondria, causing activation of caspase-9 in anterior horn cells and dorsal root ganglia neurons in mouse embryos at embryonic day 11.5.

Animals↗

PubMed2000

Electron microscopic observation and single-stranded DNA binding activity of the Mcm4,6,7 complex.

Mcm2-7 proteins that play an essential role in eukaryotic DNA replication contain DNA-dependent ATPase motifs in a central domain that, from yeast to mammals, is highly conserved. Our group has reported that a DNA helicase activity is associated with a 600 kDa human Mcm4, 6 and 7 complex. The structure of the Mcm4,6,7 complex was visualized by electron microscopy after negative staining with uranyl acetate. The complex contained toroidal forms with a central channel and also contained structures with a slit. Gel-shift analysis indicated that the level of affinity of the Mcm4,6,7 complex for single-stranded DNA was comparable to that of SV40 T antigen, although the Mcm4,6,7 complex required longer single-stranded DNA for the binding than did SV40 T antigen. The nucleoprotein complexes of Mcm4,6,7 and single-stranded DNA were visualized as beads in a queue or beads on string-like structures. The formation of these nucleoprotein complexes was erased by Mcm2 that is a potential inhibitor of the Mcm4,6,7 helicase. We also found that the DNA helicase activity of Mcm4,6,7 complex was inhibited by the binding of Mcm3,5 complex. These results support the notion that the Mcm4,6,7 complex functions as a DNA helicase and the formation of 600 kDa complex is essential for the activity.

Animals↗

PubMed2000

An auxiliary mode of apoptotic DNA fragmentation provided by phagocytes.

CAD (caspase-activated DNase) can cause DNA fragmentation in apoptotic cells. Transgenic mice that ubiquitously express a caspase-resistant form of the CAD inhibitor (ICAD) were generated. Thymocytes prepared from the mice were resistant to DNA fragmentation induced by a variety of stimuli. However, similar numbers of TUNEL-positive cells were present in adult tissues of transgenic and wild-type mice. Exposure to gamma-irradiation caused a striking increase in the number of TUNEL-positive cells in the thymus of wild-type, but not transgenic, mice. TUNEL-positive nuclei in transgenic mice were confined to thymic macrophages. When apoptotic thymocytes from the transgenic mice were cocultured with macrophages, the thymocytes underwent phagocytosis and their chromosomal DNA underwent fragmentation. This DNA fragmentation was sensitive to inhibitors that block the acidification of lysosomes. Hence, we conclude that the DNA fragmentation that occurs during apoptosis not only can result cell-autonomously from CAD activity but can also be attributed to a lysosomal acid DNase(s), most likely DNase II, after the apoptotic cells are engulfed.

Animals↗

PubMed2000

Cloning and expression study of the mouse tetrodotoxin-resistant voltage-gated sodium channel alpha subunit NaT/Scn11a.

We have cloned a tetrodotoxin-resistant (TTX-R) voltage-gated sodium channel alpha subunit from a mouse cDNA library and designated it as NaT. It encodes 1765 amino acid residues and is virtually identical to that of Scn11a, which has been reported recently, except for 40 nt and 14 aa substitutions. The amino acid identity of NaT/Scn11a with rat NaN/SNS2 is 88%. NaT/Scn11a was mapped to mouse chromosome 9F3-F4 by fluorescence in situ hybridization (FISH). While rat NaN/SNS2 has been reported to be expressed specifically in the peripheral sensory neurons, NaT/Scn11a is expressed not only in the peripheral sensory neurons but also in the spinal cord, uterus, testis, ovary, placenta, and small intestine. NaT is detectable in mouse embryos 15 days postcoitus (p.c.), around the phase of organogenesis and gonadal differentiation. These findings demonstrate a unique distribution of NaT/Scn11a and suggest some of its roles in the above-mentioned processes.

Amino Acid Sequence↗

PubMed2000

Identification of a novel human voltage-gated sodium channel alpha subunit gene, SCN12A.

We have cloned a cDNA encoding a novel human voltage-gated sodium channel alpha subunit gene, SCN12A, from human brain. Two alternative splicing variants for SCN12A have been identified. The longest open reading frame of SCN12A encodes 1791 amino acid residues. The deduced amino acid sequence of SCN12A shows 37-73% similarity with various other mammalian sodium channels. The presence of a serine residue (S360) in the SS2 segment of domain I suggests that SCN12A is resistant to tetrodotoxin (TTX), as in the cases of rat Scn10a (rPN3/SNS) and rat Scn11a (NaN/SNS2). SCN12A is expressed predominantly in olfactory bulb, hippocampus, cerebellar cortex, spinal cord, spleen, small intestine, and placenta. Although expression level could not be determined, SCN12A is also expressed in dorsal root ganglia (DRG). Both neurons and glial cells express SCN12A. SCN12A maps to human chromosome 3p23-p21.3. These results suggest that SCN12A is a tetrodotoxin-resistant (TTX-R) sodium channel expressed in the central nervous system and nonneural tissues.

Amino Acid Sequence↗

PubMed2000

Novel biphasic effect of pyrrolidine dithiocarbamate on neuronal cell viability is mediated by the differential regulation of intracellular zinc and copper ion levels, NF-kappaB, and MAP kinases.

Nuclear factor kappaB (NF-kappaB) is a transcription factor involved in the expression of a wide range of genes, most of which code for proteins that play a role in immunity and inflammation. Pyrrolidine dithiocarbamate (PDTC) is a well-known inhibitor of NF-kappaB. Although its mechanism of action is conferred by its antioxidant property, other mechanisms by which PDTC can act as a prooxidant, metal chelator, and free thiol group modulator have recently been suggested. Here we report that PDTC caused a dual effect on cell viability in neuronal rat pheochromocytoma (PC12) cells, depending on its concentration. Increase of intracellular zinc and copper ion levels selectively potentiated the cytotoxic PDTC effect in a dose-dependent manner, and thiol reagents, such as glutathione and N-acetylcysteine, as well as divalent metal-chelating reagents, such as EDTA and bathocuproline disulfonic acid, blocked its cell death effect. The differential effect of PDTC on cell viability correlates well with the inhibition of NF-kappaB activities. In addition, PDTC differentially activated microtubule-associated protein (MAP) kinases, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), but not p38, depending on its dose, and the coaddition of glutathione (GSH), other antioxidants, and metal ions also modulated their activities. Furthermore, stable Bcl-2 expression blocked the PDTC-induced cell death. These results suggest that the thiol groups and free zinc and copper ion levels are important for the novel biphasic PDTC effect on cell viability, which is associated with the differential activation of NF-kappaB and MAP kinases.

Animals↗

PubMed2000

Immunohistochemical detection of cathepsin D, K, and L in the process of endochondral ossification in the human.

Cathepsins D, K, and L were immunolocalized in tissue undergoing endochondral ossification in the human. Cathepsins D, K, and L were localized in osteoclasts and chondroclasts attached to bone matrix and cartilage matrix, respectively. Cathepsins D and L were immunostained in chondrocytes. Immunolocalization of cathepsin D was limited to hypertrophic chondrocytes adjacent to the osteochondral junction. In contrast, cathepsin L was immunolocalized in both proliferating and hypertrophic chondrocytes. In the bone marrow space, cathepsins D, K, and L were localized in multinucleated cells. Cathepsin D was diffusely detected in mononuclear bone marrow cells which were negative for cathepsins K and L. The present findings indicated that cathepsins K, D, and L were associated with the process of endochondral ossification in the human, and suggested that these cathepsins share roles in bone and cartilage turnover in the human.

Bone Marrow↗

PubMed2000

Reduction in bone formation and elevated bone resorption in ovariectomized rats with special reference to acute inflammation.

Changes in bone modeling and remodeling in the tibia of growing rats within 30 days of ovariectomy (ovx) were evaluated by histomorphometric, mechanical; and biochemical means. Three days after ovx, suppressed bone formation was seen. This was shown by reduced osteoid volume, osteoblast surface, and bone formation rate in the secondary spongiosa, and a reduced longitudinal growth rate in the growth plate. In addition, the alkaline phosphatase and tartrate-resistant acid phosphatase activity in bone marrow supernatants was suppressed in conjunction with elevated serum sialic acid levels, indicating inflammation. Although estrogen deprivation itself may provoke the inflammatory process, the serum sialic acid level in the ovx group returned to the baseline level within 5 days after surgery, while that of estradiol in the ovx group remained consistently lower. This suggests that surgical stress, not estrogen deprivation, is the primary cause of the inflammatory response shortly after ovx. A significant difference (p < 0.01) between the ovx and sham rats was seen in the osteoclast surface, which peaked on day 7 in the ovx rats. On day 14 postovariectomy, the bone formation rate peaked and remained constant until day 30. In the ovx rats, there was a sustained reduction in the serum albumin level until day 30. Estrogen deprivation may be the primary cause of these changes, because both surgical ovx and medical oophorectomy with gonadotropin-releasing hormone agonist (G(nRHa) reduce the serum albumin level. In numerous studies dealing with changes after ovx in rats, we have observed: 1) a transient reduction in bone formation in relation to inflammatory changes evoked by ovx surgery, and 2) a sustained reduction in the serum albumin level for at least 30 days after ovx that is possibly due to estrogen deprivation.

Alkaline Phosphatase↗

PubMed2000

New ocular movement detector system as a communication tool in ventilator-assisted Werdnig-Hoffmann disease.

A non-contact communication system was developed for a ventilator-assisted patient with Werdnig-Hoffmann disease who had lost all voluntary movements except for those of the eye. The system detects the extraocular movements and converts them to either a 'yes' signal (produced by one lateral eyeball movement) or a 'no' signal (produced by two successive lateral eyeball movements) using a video camera placed outside the patient's visual field. The patient is thus able to concentrate on performing a task without any intrusion from the detection system. Once the setting conditions of the device have been selected, there is no need for any resetting, as the patient is unable to move his body. In addition to playing television games, the child can use the device to select television channels, compose music, and learn written Japanese and Chinese characters. This seems to broaden the patient's daily world and promote mental development.

Activities of Daily Living↗

PubMed2000

Selective localization of Bcl-2 to the inner mitochondrial and smooth endoplasmic reticulum membranes in mammalian cells.

Bcl-2, an anti-apoptotic protein, is believed to be localized in the outer mitochondrial membrane, endoplasmic reticulum, and nuclear envelope. However, Bcl-2 has also been suggested as playing a role in the maintenance of mitochondrial membrane potential, indicating its possible association with the inner mitochondrial membrane. We therefore further examined the exact localization of Bcl-2 in mitochondria purified from wild-type and bcl-2-transfected PC12 cells and pre- and postnatal rat brains. Double immunostaining demonstrated that Bcl-2 was co-localized with subunit beta of F1F0ATPase in the inner mitochondrial membrane. Biochemical analysis of isolated mitochondria using digitonin and trypsin suggests an association of Bcl-2 with the inner mitochondrial membrane. More interestingly, the majority of Bcl-2 disappeared from the inner membrane of mitochondria when cultured under serum deprivation. These results suggest that Bcl-2 acts as an anti-apoptotic regulator by localizing mainly to the inner mitochondrial and smooth ER membranes.

Animals↗

PubMed2000

Involvement of multinucleated giant cells synthesizing cathepsin K in calcified tendinitis of the rotator cuff tendons.

OBJECTIVES: Calcified tendinitis of the shoulder joint is a common painful condition. Resorption of the calcium deposits is one of the key events in the pathogenesis of this disease. The aim of this study was to examine whether the multinucleated giant cells that appear in this condition have osteoclast phenotypes. METHODS: Immunohistochemical and RNA in situ hybridization analysis of cathepsin K, a marker for osteoclasts, was performed in human surgical samples. RESULTS: The multinucleated cells located near the calcium deposits were positive for cathepsin K protein and mRNA. Reverse transcription-polymerase chain reaction using human cathepsin K-specific oligonucleotide primers confirmed that synthesis of cathepsin K mRNA occurs in the tissues of calcified rotator cuffs. CONCLUSION: The multinucleated giant cells which appear in the resorption area of calcium deposits in calcified tendinitis have the osteoclast phenotype.

Arthrography↗

PubMed2000

A comparison of distilled water and normal saline as diluents for endobronchial administration of epinephrine in the dog.

UNLABELLED: We compared the effects of distilled water and normal saline as diluents for the endobronchial administration of epinephrine in anesthetized dogs by using a cross-over design. Six dogs received 2 mL of either normal saline or distilled water into the bronchus, and the other solution was administered 1 wk later. Eight dogs received 0.02 mg/kg epinephrine diluted in either distilled water (E + water) or normal saline (E + saline) to a total volume of 2 mL into the bronchus, and the other solution was administered 1 wk later. Normal saline or distilled water without epinephrine did not affect the plasma epinephrine concentration, mean arterial pressure (MAP), and PaO(2). The peak plasma epinephrine concentration was significantly larger after treatment with E + water (26.5 +/- 7.9 ng/mL) than after E + saline (2.1 +/- 0.7 ng/mL). E + water caused an increase in MAP of 91 +/- 24 mm Hg, whereas E + saline did not affect MAP. The maximal decrease in PaO(2) after the administration of E + water (14 +/- 5 mm Hg) was significantly greater than after E + saline (7 +/- 2 mm Hg). In conclusion, distilled water as the diluent for endobronchially administered epinephrine to a total volume of 2 mL allowed better absorption of epinephrine compared with normal saline without a serious detrimental effect on PaO(2). IMPLICATIONS: Using a small volume of distilled water as the diluent for endobronchial epinephrine administration significantly increased epinephrine absorption and arterial pressure in comparison with normal saline, without having a serious detrimental effect on PaO(2), in an anesthetized, noncardiopulmonary, resuscitation dog model.

Animals↗

PubMed2000

Identification and analysis of the K5 gene of Kaposi's sarcoma-associated herpesvirus.

Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8 (HHV-8), belongs to the gammaherpesvirus subfamily and encodes approximately 80 open reading frames (ORFs). Among them are a few candidates for immediate-early genes (e.g., K5). We developed a monoclonal antibody (MAb), 328C7, against the K5 antigen. This MAb reacted with the K5 gene product by immunoscreening of a cDNA library from BCBL-1 cells, and this result was confirmed by transfection of the K5 ORF into Cos-7 cells. After induction of lytic infection by treatment with 12-O-tetradecanoylphorbol-13-acetate, MAb 328C7 reacted with an antigen in the cytoplasm of BCBL-1 and BC-3 cells as early as after 4 h of induction. Immunoelectron microscopy showed that the K5 antigen was situated mainly in the endoplasmic reticulum but was not present on the virion or in the nucleus. Northern blotting with a K5-specific probe revealed a single transcript of 1.2 kb, while Western blotting showed the antigen to be a 36-kDa polypeptide. The 5' and 3' ends were then determined by rapid amplification of cDNA, followed by sequencing of RACE products, and a splice was revealed upstream of the K5 ORF. K5 expression was unaffected by the respective DNA and protein synthesis inhibitors phosphonoformic acid and cycloheximide plus actinomycin D, confirming its immediate-early nature. Transient-transfection assays showed that the K5 promoter was transactivated by ORF 50 (KSHV Rta), a homolog of Epstein-Barr virus Rta, but the K5 gene product exhibited no transregulation of its own promoter or those of DNA polymerase and the human immunodeficiency virus type 1 long terminal repeat. This is the first such analysis of an immediate-early gene product; determination of its specific biological function requires further investigation.

Animals↗