Search PubMed⌕ Search

Biomedical subjects

K Arai

Publications and source records attributed to K Arai.

At least 37 records · Page 2Linked to original sources
PubMed2003

RhoA is associated with invasion and lymph node metastasis in upper urinary tract cancer.

OBJECTIVE: To assess the roles of RhoA small GTPase (RhoA) in upper urinary tract cancer by analysing the mRNA and protein levels of RhoA. PATIENTS AND METHODS: The mRNA and protein levels of RhoA in matched sets of tumour, non-tumour and metastatic lymph node tissues of surgical specimens were analysed in 47 consecutive patients with renal pelvic/ureteric cancer, using the polymerase chain reaction after reverse transcription and Western blotting. The relationship between mRNA and protein levels of RhoA in tumour tissues and the clinicopathological features of the patients was also assessed. RESULTS: The mRNA levels of RhoA and RhoA protein were greater in tumour and metastatic lymph node tissues than in non-tumour tissues (all P < 0.001). The expression levels of RhoA mRNA and protein levels in primary tumours was related to poorly differentiated grade (both P < 0.05) and muscle invasion (P < 0.01 and < 0.001, respectively). Kaplan-Meier plots of survival in patients with low or high RhoA showed that high mRNA and protein levels were associated with a shorter disease-free (P < 0.01) and overall survival (P < 0.001). Multivariate analysis using the Cox proportional hazards model showed that a high RhoA protein level was an independent prognostic factor, second to stage, in disease-free and overall survival (both P < 0.05). CONCLUSIONS: These findings suggest that RhoA is involved in the invasion and metastasis of upper urinary tract cancer, indicating that RhoA may be a useful prognostic factor in this disease.

Aged↗
PubMed2003

The Ishiguro extension block technique for the treatment of mallet finger fracture: indications and clinical results.

The results of extension block Kirschner wire fixation for the treatment of mallet fractures of the distal phalanx were retrospectively assessed in 65 consecutive patients. The indications for this technique were the presence of a large bone fragment, and palmar subluxation or the loss of joint congruity of the distal interphalangeal joint. Using the Wehbé and Scheider classification there were 27 type IB, 19 type IIB, 17 type IA, and 2 type IIA fractures. According to the Crawford rating system there were 46% excellent, 32% good, 20% fair and 2% poor results. We believe that this technique, when properly applied, produces satisfactory results.

Adolescent↗
PubMed2003

Endogenous prostaglandin I2 regulates the neural emergency system through release of calcitonin gene related peptide.

BACKGROUND: We previously reported that endogenous prostaglandin I(2), generated by a mild irritant, sensitised calcitonin gene related peptide (CGRP) containing sensory nerves and facilitated the release of CGRP and gastric mucosal protection against ethanol. Administration of capsaicin also inhibited ethanol induced gastric mucosal injury through immediate release of CGRP from primary sensory neurones, which is termed the neural emergency system. In the present study, we tested whether endogenous prostaglandin I(2) also modulates the cytoprotective action of capsaicin using prostaglandin I receptor knockout mice (IP(-/-)). METHODS: The stomachs of IP(-/-) or their wild-type counterparts (IP(+/+)), anaesthetised with urethane (1.225 g/kg), were doubly cannulated from the oesophageal and duodenal sides, and the gastric mucosa was perfused (1 ml/min) with physiological saline. Perfusate was changed to 50% ethanol alone, or 50% ethanol containing capsaicin (16 approximately 1600 micro M). The injured area was estimated at the end of each perfusion experiment. In some animals, CGRP-(8-37), a CGRP antagonist (0.3 mg/kg), or indomethacin (1 mg/kg) was intravenously injected before perfusion of 50% ethanol containing capsaicin. RESULTS: Capsaicin inhibited the injured area in a dose dependent manner. Fifty per cent ethanol containing capsaicin (480 micro M) immediately increased intragastric levels of CGRP although 50% ethanol alone did not. The protective action of capsaicin (480 micro M) against ethanol was completely abolished by intravenous injection of CGRP-(8-37). Indomethacin also inhibited the protective action of capsaicin, and this was accompanied by reduced levels of intragastric CGRP. Intragastric levels of prostaglandin E(2) were not increased by capsaicin treatment but those of 6-keto-prostaglandin F(1alpha), a metabolite of prostaglandin I(2), were markedly increased. No protective action of capsaicin was observed in IP(-/-) which lacked the ability to increase intragastric CGRP levels in response to ethanol containing capsaicin. The CGRP content of the stomach from untreated IP(-/-) did not differ from those in IP(+/+). Capsaicin (160 micro M) together with intragastric perfusion of beraprost sodium (PGI(2) analogue, 2.5 micro g/ml) showed enhanced protection against ethanol induced injury. This enhanced protection was completely blocked by intravenous injection of CGRP-(8-37). CONCLUSIONS: The present results suggest that endogenous prostaglandin I(2) enhances the protective action of the capsaicin mediated neural emergency system against ethanol induced gastric mucosal injury through enhancement of CGRP release.

6-Ketoprostaglandin F1 alpha↗
PubMed2003

Expression of class II beta-tubulin by proliferative myoepithelial cells in canine mammary mixed tumors.

Benign mammary mixed tumors in dogs resemble human salivary pleomorphic adenomas with regard to their histogenesis, including the occurrence of cartilaginous or bony metaplasia as well as the expression pattern of cytoskeletal proteins in proliferative myoepithelial cells. Recently, a monoclonal antibody specific for class II beta-tubulin has been developed. The epitope it recognizes was determined to be the heptapeptide Glu-Glu-Glu-Glu-Gly-Glu-Asp, which is the common sequence found among the canine, rat, mouse, and human class II beta-tubulin-specific regions. We carried out immunohistochemical studies on mammary mixed tumors obtained from three female dogs using this the monoclonal antibody. The antibody to class II beta-tubulin reacted intensely with proliferative myoepithelial cells in canine mammary mixed tumors, whereas staining was barely detectable in normal myoepithelial cells surrounding alveoli and alveolar ducts within the tumor and adjacent normal tissue. Proliferative myoepithelial cells also expressed vimentin, but alpha-smooth muscle actin (alphaSMA) staining was barely detectable. Immunoblot analysis showed that class II beta-tubulin and vimentin were expressed in myoepithelial cell lines prepared from the three mammary mixed tumors. On the other hand, only one cell line, which was negative for alphaSMA, produced cartilage-specific type II collagen. These results suggest that class II beta-tubulin could be a new molecular marker of proliferating myoepithelial cells in canine mammary mixed tumors and that differential expression of cytoskeletal components is associated with cartilaginous metaplasia of proliferative myoepithelial cells in mixed mammary tumors.

Amino Acid Sequence↗
PubMed2002

Superconductivity and magnetic fluctuations in Cd(2))Re(2)O(7) via Cd nuclear magnetic resonance and re nuclear quadrupole resonance.

We report Cd nuclear magnetic resonance (NMR) and Re nuclear quadrupole resonance (NQR) studies on Cd(2)Re(2)O(7), the first superconductor among pyrochlore oxides (T(c) approximately 1 K). The Re NQR spectrum at zero magnetic field below 100 K rules out any magnetic or charge order. The spin-lattice relaxation rate below T(c) exhibits a pronounced coherence peak and follows the weak-coupling BCS theory with nearly isotropic energy gap. The results of Cd NMR point to a moderate ferromagnetic enhancement at high temperatures followed by a rapid decrease of the density of states below the structural transition temperature of 200 K.

Journal Article↗
PubMed2002

Binding evaluation of the combination between the superconductor and matrix by ultrasonic spectra.

Combination of the superconductor and high conductive normal metal is now indispensable in the practical use of superconducting magnet. And the binding property of both materials is one of the key points whether superconductive characteristics are fully attained or the current fails prematurely in the practical magnet. But this binding evaluation is not so easy, because even in the mechanically well-jointed conductor, it often appears poor in electric and magnetic joint in cryogenic temperature. Since we have examined and reported fundamental AE properties of superconductor from UI-91, UI-93, UI-95, and UI-97, we have found the simple but important discovery for getting new information about the binding evaluation. Here we report a new technique for evaluating these bindings by observing ultrasonic spectra when a normal transition is propagated along the superconductor. We have discovered that a good contacting conductor has an emission of this sound with sharp resonating frequency peak or peaks at around the highest spectrum area; from 0.5 to 1.0 MHz. Our interpretation of the evaluations are so simple that we can say that binding degrees are best, good or bad, according to the resonating Q-value at around the highest spectrum of the ultrasonic sound.

Journal Article↗
PubMed2002

A patient homozygous for the SCA6 gene with retinitis pigmentosa.

The present authors studied a 55-year-old-patient homozygous for the SCA6 gene who experienced frequent attacks of positional vertigo at 37 years of age with subsequent staggering gait and night blindness. Retinitis pigmentosa (RP), as well as cerebellar ataxia and vertical antidirectional nystagmus, were detected. The subject's parents were first cousins, and two of his three male cousins, whose parents were also first cousins, had RP without ataxia or nystagmus. The numbers of CAG repeats in the expanded alleles of the SCA6 gene found by molecular analysis were 21 and 21. The genetic results were negative for SCA1, SCA2, SCA3, SCA7 and dentatorubral pallidoluysian atrophy. The retinal degeneration in this patient is most likely to be secondary to a genetic disorder of autosomal or X-linked recessive inheritance rather than SCA6. Other reported cases of patients homozygous for the SCA6 gene are also reviewed.

Calcium Channels↗
PubMed2002

Na,K-ATPase alpha3 subunit in the goldfish retina during optic nerve regeneration.

The goldfish optic nerve can regenerate after injury. To understand the molecular mechanism of optic nerve regrowth, we identified genes whose expression is specifically up-regulated during the early stage of optic nerve regeneration. A cDNA library constructed from goldfish retina 5 days after transection was screened by differential hybridization with cDNA probes derived from axotomized or normal retina. Of six cDNA clones isolated, one clone was identified as the Na,K-ATPase catalytic subunit alpha3 isoform by high- sequence homology. In northern hybridization, the expression level of the mRNA was significantly increased at 2 days and peaked at 5-10 days, and then gradually decreased and returned to control level by 45 days after optic nerve transection. Both in situ hybridization and immunohistochemical staining have revealed the location of this transient retinal change after optic nerve transection. The increased expression was observed only in the ganglion cell layer and optic nerve fiber layer at 5-20 days after optic nerve transection. In an explant culture system, neurite outgrowth from the retina 7 days after optic nerve transection was spontaneously promoted. A low concentration of ouabain (50-100 nm ) completely blocked the spontaneous neurite outgrowth from the lesioned retina. Together, these data indicate that up-regulation of the Na,K-ATPase alpha3 subunit is involved in the regrowth of ganglion cell axons after axotomy.

Amino Acid Sequence↗
PubMed2002

Progressive supranuclear palsy: neuronal and glial cytoskeletal pathology in the higher order processing autonomic nuclei of the lower brainstem.

The medial and lateral parabrachial nuclei (MPB, LPB), the gigantocellular reticular nucleus (GI), the raphes magnus (RMG) and raphes obscurus nuclei (ROB), as well as the intermediate reticular zone (IRZ) represent pivotal subordinate brainstem centres, all of which control autonomic functions. In this study, we investigated the occurrence and severity of the neuronal and glial cytoskeletal pathology in these six brainstem nuclei from 17 individuals with clinically diagnosed and neuropathologically confirmed progressive supranuclear palsy (PSP). The association between the severity of the pathology and the duration of the disease was investigated by means of correlation analysis. The brainstem nuclei in all of the PSP cases were affected by the neuronal cytoskeletal pathology, with the IRZ and GI regularly showing severe involvement, the MPB, RMG, and ROB marked involvement, and the LPB mild involvement. In the six nuclear greys studied, glial cells undergo alterations of their cytoskeleton on an irregular basis, whereby diseased oligodendrocytes predominantly presented as coiled bodies and affected astrocytes as thorn-shaped astrocytes. In all six nuclei, the severity of the neuronal or glial cytoskeletal pathology showed no correlation with the duration of PSP. In view of their functional role, the neuronal pathology in the nuclei studied offers a possible explanation for the autonomic dysfunctions that eventually develop in the course of PSP.

Aged↗
PubMed2002

Clinicopathological analysis of early gastric cancer with solitary lymph node metastasis.

BACKGROUND: The sentinel node concept has not yet been established in gastric cancer. METHODS: Fifty-four patients with early gastric cancer who had only one lymph node metastasis were regarded retrospectively as patients with a possible sentinel node metastasis, and the morphological features of these nodes were assessed. The level I nodes in seven patients with a possible skip metastasis at routine haematoxylin and eosin staining were re-examined using cytokeratin (CK) immunostaining. RESULTS: The shape of the gastric cancer lesion could be examined in 53 of the patients; more than one-third (20 of 53) were microfocal type. Concerning the intranodal cancer foci, the marginal sinus type was found in 32 affected nodes, medullary sinus type in 14 and mixed type in seven. Forty-three per cent of suspected sentinel nodes were the largest in size among all nodes from the station. CK immunostaining of seven non-metastatic nodes with haematoxylin and eosin revealed that three were CK positive. CONCLUSION: These findings suggest that possible sentinel nodes detected by conventional means may not always be primary portions of any metastasis. Adoption of sentinel node biopsy in gastric cancer must await the development of improved procedures for diagnosis during surgery.

Humans↗
PubMed2002

The rho/rho-kinase pathway is involved in the progression of testicular germ cell tumour.

OBJECTIVE: To clarify the role of one of the downstream effectors of Rho (Rho-kinase) in testicular germ cell tumour (GCT) by quantifying mRNA expression for Rho-kinase in patients with this disease. MATERIALS AND METHODS: The mRNA levels of the RhoA and Rho-kinase genes were analysed in surgical specimens of testicular GCT tissues from 57 consecutive Japanese patients, and in the corresponding non-tumour tissue originating from the same patient, using the polymerase chain reaction after reverse transcription. The expression levels of these genes were compared between the tissues and the relationship between their expression levels evaluated within tumours and with tumour stage. The difference in the expression levels of the mRNAs of RhoA and Rho-kinase genes were also assessed between tumours that were seminoma only and mixed tumours of seminoma and nonseminoma. RESULTS: RhoA and Rho-kinase mRNAs were more abundant in tumour tissue than in non-tumour tissue (P < 0.01 and < 0.05, respectively). High RhoA and Rho-kinase mRNA expressions were related to tumour stage (P < 0.05 and < 0.01, respectively). The mRNA levels of RhoA and Rho-kinase in mixed tumours were higher than in tumours with seminoma only (P < 0.01 and < 0.05, respectively). There was a positive relationship between expression levels of mRNAs of RhoA and Rho-kinase in tumour tissues (P < 0.001). CONCLUSIONS: These findings suggest that the RhoA/Rho-kinase pathway is involved in the progression of testicular GCT. This pathway might be a molecular target for new treatment strategies for this disease.

Adolescent↗
PubMed2002

Treatment of soft tissue injuries to the dorsum of the metacarpophalangeal joint (Boxer's knuckle).

We retrospectively reviewed the surgical treatment for 16 cases of traumatic soft tissue injury to the metacarpophalangeal joint (Boxer's knuckle). A history of trauma was present in all cases and there was an associated extensor tendon dislocation in seven cases. Eight cases were initially treated conservatively, but their symptoms persisted. Intraoperative findings included rupture of the extensor hood or joint capsule in all cases. Surgical closure of the rupture of the joint capsule resulted in a successful outcome in all cases. We consider that conservative treatment of this injury may not be effective when the joint capsule of the metacarpophalangeal joint is ruptured. We recommend arthrography of the metacarpophalangeal joint to assist in the decision as to whether to proceed with surgical or conservative treatment.

Adolescent↗
PubMed2002

The carpal detachment injury of the triangular fibrocartilage complex.

Triangular fibrocartilage complex (TFCC) injuries were suspected clinically in 22 wrists of 21 patients, but arthrography and MRI assessments of this structure were normal. As conservative therapy for 2 months did not improve their symptoms, wrist arthroscopy was then performed. Although no abnormalities of the TFCC and ligaments were observed, meniscus homologue-like tissue which arose from TFCC was riding on the articular surface of the triquetrum. After resection of this soft tissue with a shaver and a punch, the symptoms disappeared in all cases. The arthroscopic findings suggested that a portion of TFCC that was originally attached to the ulnar side of the triquetrum had become detached.

Adolescent↗
PubMed2002

Distraction lengthening by callotasis in the hand.

The clinical results of 26 digits (18 patients) lengthened by distraction callotasis were evaluated and the factors which influenced healing were analysed. There were 14 men and four women, with a mean age of 39 years. All digits had suffered traumatic amputation. There were eight thumbs and 18 fingers. The level of the site of the osteotomy was at the proximal metaphysis in ten, the middle diaphysis in 13 and the distal metaphysis in three. Although the proposed length was achieved in 23 of the 26 digits, five required additional bone grafts. The rate of healing was 96 days/cm in the digits without complications such as callus fracture or poor callus formation, and 158 days/cm in those with complications. Lengthening at the proximal metaphysis gave a better result than at the diaphysis or distal metaphysis.

Adolescent↗
PubMed2002

Potential role of activin A in follicular development during the second half of pregnancy in the golden hamster: utero-placental source of activin A.

Numerous antral follicles develop during the second half of pregnancy in the golden hamster. However, mechanisms regulating follicular development during this period are unknown. Because inhibin and activin are related to follicular development, these hormones were studied to gain insight into any potential roles in follicular development. Plasma inhibin A and B suddenly increased from day 8 of pregnancy, reached peak levels on day 10 and gradually declined to term. Plasma activin A gradually increased from day 8 to day 15 of pregnancy, and this was followed by an abrupt decrease at day one of lactation. Ovariectomy on day 12 of pregnancy rapidly reduced plasma inhibin A and B, but not activin A levels. Hysterectomy or placentectomy on day 12 of pregnancy caused an abrupt decrease in the levels of plasma activin A and FSH, but not inhibin A and B at 6 h after surgery. Hysterectomy also induced atresia of large antral follicles at 24 h after surgery. These results indicate that antral follicles are the main source of circulating inhibin A and B, whereas uteri and placentae are the main source of circulating activin A. These results suggest that increased levels of activin A may be involved in folliculogenesis in the ovary during the second half of pregnancy in the golden hamster.

Activins↗
PubMed2002

Secretory pattern of inhibin A, inhibin B and inhibin pro-alpha C during induced follicular atresia and subsequent follicular development in the golden hamster (Mesocricetus auratus).

The changes in plasma concentrations of inhibins A, B and pro-alpha C were determined in the cyclic golden hamster during follicular atresia induced with antiserum against luteinizing hormone releasing hormone (LHRH-AS) at 1100 h on day 4 (day 1=day of ovulation). Follicular status in the ovary was also studied by determining the number of follicles ovulating in response to human chorionic gonadotrophin (hCG) injection. The time-courses of changes in plasma concentrations of inhibins A, B and pro-alpha C were different from each other during induced follicular atresia and subsequent follicular development. Plasma concentrations of inhibin A decreased to 58.6% of initial values by 24 h after LHRH-AS treatment, and then remained relatively low until at least 60 h later. Plasma concentrations of inhibin B decreased to 64.2% of the initial values by 18 h after LHRH-AS treatment and remained at basal values for 36 h, but increased abruptly to greater than initial values at 42 h after the treatment. Plasma concentrations of inhibin pro-alpha C increased at 6 and 12 h, decreased suddenly to 21.9% of the initial values by 24 h after LHRH-AS treatment, and then gradually increased until 60 h after LHRH-AS. The number of follicles responding to hCG decreased gradually between 0 and 30 h after LHRH-AS, when no ovulations were observed, and then gradually increased until 60 h. The changes in follicular ovulatory responses to hCG correlated with the plasma profile of inhibin A throughout the experiment. These results suggest that inhibin A is mainly secreted by large antral follicles. In contrast, during the subsequent follicular development, the plasma concentration of inhibin B increased earlier than that of inhibin A. These results suggest that inhibin B is secreted by small and large antral follicles. Plasma concentrations of inhibin pro-alpha C were high at a time when plasma concentrations of oestradiol-17 beta had already decreased, indicating that inhibin pro-alpha C is secreted not only from healthy follicles but also from early atretic antral follicles.

Animals↗
PubMed2001

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF) stimulates primitive and definitive erythropoiesis in mouse embryos expressing hGM-CSF receptors but not erythropoietin receptors.

Although erythropoietin (EPO) and its receptor (EPOR) are crucial for the proliferation, survival, and terminal differentiation of erythroid progenitors, it remains to be elucidated whether EPOR-unique signaling is required for erythropoiesis. To address this issue, human granulocyte-macrophage colony-stimulating factor (hGM-CSF) receptor (hGMR)-transgenic mice and heterozygous EPOR mutant mice were crossed by in vitro fertilization. In methylcellulose clonal culture of fetal liver (FL) cells of generated hGMR-expressing EPOR(-/-) embryos at embryonic day (E) 12.5 of gestation, hGM-CSF stimulated erythroid colony formation under serum-containing and serum-free conditions. Analysis of globin expression in individual erythrocyte-containing colonies formed from E12.5 FL cells showed that hGM-CSF supports primitive and definitive erythropoiesis even in EPOR(-/-) embryos. In comparison of activities between hGM-CSF and EPO in hGMR-expressing EPOR(+/+) embryos, the 2 substances supported the formation of similar numbers of erythroid colonies in clonal culture of E12.5 FL cells; enhanced adult, but not embryonic, globin synthesis; and induced increase of GATA-1 expression and decrease of erythroid Kruppel-like factor and cMyb expression in the FL cells. On the other hand, in E8.0 yolk sac erythropoiesis, both substances had a similar effect on erythroid colony formation, but hGM-CSF induced an increase of beta-major globin expression, while EPO did not. All together, the results of the present study demonstrated that hGM-CSF can stimulate the proliferation and differentiation of primitive and definitive erythroid cells independently of EPOR signal if they express hGMR, and the activity is comparable to that of EPO in definitive, but not primitive, erythropoiesis.

Animals↗