Biomedical subjects

Y Taniguchi

Publications and source records attributed to Y Taniguchi.

At least 37 records · Page 2Linked to original sources

PubMed2002

Rotatory subluxation of the scaphoid in Kienböck's disease is not a cause of scapholunate advanced collapse (SLAC) in the wrist.

We have examined whether the rotatory subluxation of the scaphoid which is seen in patients with advanced Kienböck's disease is associated with scapholunate advanced collapse (SLAC) wrist. We studied 16 patients (11 men, 5 women) who had stage-IV Kienböck's disease with chronic subluxation of the scaphoid. All had received conservative treatment. The mean period of affection with Kienböck's disease was 30 years (14 to 49). No wrist had SLAC. In eight patients, 24 years or more after the onset of the disease, the articular surface of the radius had been remodelled by the subluxed scaphoid with maintenance of the joint space. The wrists of six patients were considered to be excellent, nine good, and one fair according to the clinical criteria of Dornan. Our findings have shown that rotatory subluxation of the scaphoid in Kienböck's disease is not a cause of SLAC wrist and therefore that scaphotrapeziotrapezoid arthrodesis is not required for the management of these patients.

Adolescent↗

PubMed2002

[Clinicopathological character and long-term results of thymic epithelial tumor categorized by WHO classification].

We analyzed clinicopathological character and long term results of 50 thymic epithelial tumors with reference to WHO histologic classification. There were 1 type A tumor, 8 type AB tumors, 13 type B1 tumors, 16 type B2 tumors, 10 type B3 tumors, and 2 type C tumors. Clinical stages were progressive in order of classification type A, AB, B1, B2, B3, and C. Type B1 and B2 were highly associated with myasthenia gravis (MG). There were four multiple thimic tumor in patients of advance clinical stage with polygonal epithelial cell tumor. Long term results were poor in order of the classification of type A, AB, B1, B2, B3, and C. In our study, WHO classification finely reflected the clinical character and prognosis of thymic epithelial tumors.

Adult↗

PubMed2001

Picometer-scale dynamical x-ray imaging of single DNA molecules.

Time-resolved dynamical x-ray imaging of individual DNA molecules with picometer-scale precision is demonstrated for the first time. Diffracted x-ray tracking (DXT), a single-molecule experiment with x rays, monitors the rotating motions, rather than the translational motions, of a labeled nanocrystal. DXT can obtain information about the dynamics of single molecules through a quantitative analysis, since the signals from DXT are independent of the chemical conditions.

DNA↗

PubMed2001

Overexpression of homeobox gene HOXD3 induces coordinate expression of metastasis-related genes in human lung cancer cells.

Homeobox-containing genes are expressed in spatiotemporal fashion during embryogenesis and act as master transcription-regulating factors which control the expression of a variety of genes involved in morphogenesis. They are also expressed in a tissue-specific manner in normal adult tissues and appear to give cells spatial information in the maintenance of their architectural integrity. We transfected a HOXD3 class I homeobox-containing gene into human lung cancer A549 cells and investigated alterations in gene expressions and phenotypes related to the maintenance of tissue architecture in HOXD3-overexpressing A549 cells. In the HOXD3-overexpressing cell lines, expression of E-cadherin was lost and plakoglobin was strongly repressed, whereas integrin alpha3 and beta3 were up-regulated and N-cadherin and integrin alpha4 were newly expressed. Compared with parental and control transfectant lines, the HOXD3-overexpressing cell lines showed highly motile and invasive activity. Blocking experiments using anti-integrin beta1 and beta3 suggested that the increased haptotaxis of the HOXD3-overexpressing cells to vitronectin resulted from increased expression and activation of integrin alphavbeta3, and that overexpression of the HOXD3 gene converted the integrin beta1-dependent haptotaxis to fibronectin into both integrin beta1- and beta3-dependent one. HOXD3 overexpression increased production of matrix-degrative enzymes including matrix metalloproteinase-2 and urokinase-plasminogen activator. When the tumor cells were intravenously injected into the tail veins of nude mice, HOXD3 transfectants formed a significantly large number of metastatic foci in lungs compared with the control transfectants. These findings suggest that HOXD3 can act as a metastasis-promoting gene in human lung cancer A549 cells.

Antigens, CD↗

PubMed2001

Natural infection of wild-born mandrills (Mandrillus sphinx) with two different types of simian immunodeficiency virus.

We found a novel primate lentivirus in mandrill (Mandrillus sphinx). To clarify the evolutionary relationships and transmission patterns of human/simian immunodeficiency virus (HIV/SIV), we screened blood samples from 30 wild-born healthy Cameroonian mandrills. Five (16.7%) of them were seropositive for SIV. Three SIV strains were isolated from the five seropositive mandrills by cocultivation of their peripheral blood mononuclear cells (PBMCs) with PBMCs of rhesus macaques, a human T cell line (M8166), and/or a cynomolgus macaque T cell line (HSC-F). One of the newly isolated SIV strains was intravenously inoculated into two rhesus macaques and resulted in chronic infection. In the SIV-infected macaques at 45 weeks after inoculation, we observed a mild decline in the number of peripheral CD4(+) lymphocytes, lymphadenopathy, and blastic follicular dendritic cells with mild follicular hyperplasia in the peripheral lymph nodes. A phylogenetic analysis based on the pol sequence showed that the newly found SIVs from Cameroonian mandrills did not cluster with SIVmndGB1, which is the former representative strain of SIVmnd. The SIVmnds from Cameroon formed a new, independent lineage that branched before the root of the HIV-1/SIVcpz lineage with 996 of 1000 bootstrap replications. They clustered host specifically, and exhibited about 16.9% diversity at the level of nucleotide sequence among Cameroonian SIVmnd strains. These results indicate that the SIVmnds isolated in Cameroon are a novel type of SIVmnd and have infected Cameroonian mandrills for a long time. We therefore designated the Cameroonian SIVmnd as SIVmnd type 2 and redesignated SIVmndGB1 as SIVmnd type 1. To date, M. sphinx is the only primate species other than humans that is naturally infected with two different types of SIV.

Animals↗

PubMed2001

Conservation of the biochemical mechanisms of signal transduction among mammalian Notch family members.

Mouse Notch1, which plays an important role in cell fate determination in development, is proteolytically processed within its transmembrane domain by unidentified gamma-secretase-like activity that depends on presenilin. To study this proteolytic event, we established a cell-free Notch cleavage assay system using the membrane fraction of fibroblast transfectants of various Notch constructs with deletion of the extracellular portion (Notch DeltaE). The cytoplasmic portion of Notch1 DeltaE was released from the membrane upon incubation at 37 degrees C, which was inhibited by the specific gamma-secretase inhibitor, MW167, or by overexpression of dominant negative presenilin1. Likewise, other members of mouse Notch family were proteolytically cleaved in a presenilin-dependent, MW167-sensitive manner in vivo as well as in the cell-free Notch DeltaE cleavage assay system. All four members of the mouse Notch family migrated to the nucleus and activated the transcription from the promoter carrying the RBP-J consensus sequences after they were released from the membrane. These results demonstrate the conserved biochemical mechanism of signal transduction among mammalian Notch family members.

Amino Acid Sequence↗

PubMed2001

Antitumor effects of Marginisporum crassissimum (Rhodophyceae), a marine red alga.

Marginisporum crassissimum (Yendo) Ganesan, a marine red alga found in the ordinal coastal sea around Japan, revealed antitumor (antimetastatic) effects in vitro and in vivo. In in vitro experiments, extracts of this alga inhibited not only the growth of several tumor cell lines, such as B16-BL6 (a mouse melanoma cell line), JYG-B (a mouse mammary carcinoma cell line) and KPL-1 (a human mammary carcinoma cell line), but also invasion of B16-BL6 cells in a culture system. In in vivo experiments, the lung metastasis of B16-BL6 cells inoculated to the tail vein of B57BL/6J mice was inhibited by intraperitoneal administration of an extract from the alga. In addition, life prolongation of B57BL/6J mice inoculated with B16-BL6 cells was also observed by the intraperitoneal administration of the extract. An effective substance showing B16-BL6 growth inhibition in vitro was partially purified by filtration and hydrophobic column chromatography, and was revealed to be sensitive to trypsin-digestion and heat-treatment. The molecular weight of the substance was greater than 100 kDa. This is the first study demonstrating antitumor (antimetastatic) effects of M. crassissimum.

Animals↗

PubMed2001

Pinopsin expressed in the retinal photoreceptors of a diurnal gecko.

Retinal cDNAs encoding the putative opsins, dg3 and dg4, were isolated from a diurnal gecko, Phelsuma madagascariensis longinsulae. dg3 mRNA is localized in about 20% of the thin members of type C double cones, and likely encodes an opsin of the ultraviolet-sensitive pigment. Surprisingly, dg4 is very similar to chicken pinopsin, a pineal-specific photoreceptive molecule. An anti-dg4 antiserum recognized a small population of photoreceptor outer segments in the retina and a large number of pinealocytes. Our results suggest that P. m. longinsulae expresses pinopsin in its retina, which usually plays a role as a photoreceptive molecule in the pineal organ.

Amino Acid Sequence↗

PubMed2001

Two KaiA-binding domains of cyanobacterial circadian clock protein KaiC.

kaiABC, a gene cluster, encodes KaiA, KaiB and KaiC proteins that are essential to circadian rhythms in the unicellular cyanobacterium Synechococcus sp. strain PCC 7942. Kai proteins can interact with each other in all possible combinations. This study identified two KaiA-binding domains (C(KABD1) and C(KABD2)) in KaiC at corresponding regions of its duplicated structure. Clock mutations on the two domains and kaiA altered the strength of C(KABD)-KaiA interactions assayed by the yeast two-hybrid system. Thus, interaction between KaiA and KaiC through C(KABD1) and C(KABD2) is likely important for circadian timing in the cyanobacterium.

Adenosine Triphosphate↗

PubMed2001

Effects of joint immobilization on firing rate modulation of human motor units.

We investigated the effects of 6 weeks of immobilization on firing rate modulation in motor units in the first dorsal interosseous (FDI) of human volunteers. The middle finger, index finger and thumb were immobilized for a period of 6 weeks in a fibre-glass cast, which kept FDI in a shortened position. During isometric contraction at 20, 40, 60 and 80 % of maximal voluntary contraction (MVC) (index finger abduction), motor unit action potentials were recorded from the FDI using a tungsten microelectrode, and the relationship between voluntary force and mean firing rate (MFR) was obtained by plotting the MFR of each motor unit action potential train as a function of voluntary force. Four recording sessions were held for each subject: before immobilization, after 3 and 6 weeks of immobilization, and after a 6 week recovery period. As a result of immobilization, FDI volume (as measured by computerized tomography (CT) scanning) decreased, with an accompanying reduction in aggregate EMG activity per day (P < 0.01). The force measured during MVC also decreased (P < 0.05). The slope of the relationship between voluntary force and MFR was significantly decreased after immobilization, as was the range of firing rate modulation (P < 0.01). Maximal MFR, estimated from the relationship between voluntary force and MFR, was decreased (P < 0.05). MFR was also plotted against voluntary force without being normalized with respect to MVC, and the slope of the regression line was decreased (P < 0.05). Voluntary force when the MFR was 15 Hz was estimated from regression equations for the absolute force-MFR relationship, and it was increased after immobilization (P < 0.05). These results suggest that firing rate modulation shows two different adaptations to joint immobilization: a restriction of motoneurone firing to the lower rates and an enhancement of the voluntary force exerted when the MFR is relatively low.

Adult↗

PubMed2001

Alterations in contractile properties of human skeletal muscle induced by joint immobilization.

The effects of joint immobilization on the contractile properties of human skeletal muscle were examined using the first dorsal interosseous (FDI) muscle. The middle finger, index finger and thumb were immobilized for a period of 6 weeks, and the contractile properties of FDI were tested before immobilization, after 3 and 6 weeks of immobilization, and after a 6 week recovery period. Twitch and tetanic contractions of FDI were evoked by per-cutaneous electrical stimulation. The peak twitch tension (Pt), contraction time (CT) and half-relaxation time (1/2RT) were measured from twitch contractions, while the stimulus frequency-force relationship was obtained from the tetanic contractions (2 s) evoked using various frequencies of stimulation (10-100 Hz). The fatigability of FDI was tested using Burke's fatigue protocol.Pt was significantly increased after 6 weeks of immobilization (P < 0.05) but little alteration was observed in CT or 1/2RT. No change was noted in the FDI fatigue index throughout the immobilization period. The stimulus frequency-force relationship was shifted to the left by immobilization, indicating that a larger percentage of maximal force was evoked by the lower rates of stimulation. Indeed, the tetanic force evoked by a stimulus frequency of 10 Hz was enhanced after immobilization (P < 0.05). On the other hand, the force evoked by frequencies above 50 Hz, including maximal tetanic tension, was decreased (P < 0.05). As a result, the twitch/tetanus ratio was increased (P < 0.01) after immobilization. The changes induced by immobilization in the FDI twitch/tetanus ratio and the estimated maximal firing rate of FDI motoneurones showed a significant correlation (r = 0.80, P < 0.05). It is suggested that the changes in the contractile properties of the FDI muscle seen after joint immobilization are causally linked to the changes in firing rate modulation of FDI motoneurones.

Adult↗

PubMed2001

Analysis of the canine IgE-binding epitope on the major allergen (Cry j 1) of Japanese cedar pollen with anti-Cry j 1 monoclonal antibodies.

In our previous study [Immunology 91 (1997) 161] using monoclonal antibodies (mAbs) specific to Cry j 1, a major allergen in Japanese cedar (Cryptomeria japonica) pollen, we identified five independent epitopes (EP-1-EP-5) on the molecule and found that EP-1 and EP-5 are the predominant allergic epitopes for humans and monkeys, respectively. In this study, we analyzed the epitopes recognized by IgE in the sera of 10 dogs sensitive to C. japonica pollen allergen using an IgE-ELISA inhibition method with these mAbs. The IgE reaction patterns varied among dogs. In eight of the 10 dogs, IgE recognized EP-5 which is a predominant allergic epitope for monkeys with the pollenosis. In four dogs, IgE recognized EP-1 which is a predominant allergic epitope for human patients with the pollenosis. In three dogs, IgE recognized EP-4 which is a heat-stable epitope. EP-5 is a predominant allergic epitope for dogs and some, but not all, dogs have IgE reaction patterns to the epitopes similar to those of humans.

Allergens↗

PubMed2001

FTIR study on heat-induced and pressure-assisted cold-induced changes in structure of bovine alpha-lactalbumin: stabilizing role of calcium ion.

The second derivative FTIR study of heat-induced and pressure-assisted cold-induced changes in the secondary structure of bovine alpha-lactalbumin was carried out for native holoprotein and calcium ion depleted apoprotein. The secondary structure and compactness of alpha-lactalbumin were examined in a temperature range from 20 to 80 degrees C during the heat treatment and 20 to -15 degrees C during the pressure-assisted cold treatment. This was the first FTIR study on the pressure-assisted cold denaturation of a protein. Because protein solutions had close to neutral pD and low ionic strength, the apoprotein remained in the molten globule state and the holoform maintained its native tertiary structure. In order to distinguish between unfolding-related and partially deuterated exchange-related spectral changes, we examined both the fully deuterated holoform and the partially deuterated holoform. The quantitative analysis of the spectral changes in the amide I/I' vibrational band revealed that the 3(10) helices were more prone to thermal unfolding than the alpha helices. We observed that the protein's compactness and secondary structure were both considerably stabilized against an increase and decrease in temperature by the presence of a calcium ion. Under the conditions of this study, only the apoprotein was susceptible to the cold denaturation. In contrast to this, an unexpected linear increase of the alpha-helical content was observed upon the cooling of the holoprotein under high pressure. The results were discussed in reference to the existing crystallographic data for crystals of human alpha-lactalbumin grown at two different temperatures.

Animals↗

PubMed2001

The lacrimal fascia redefined.

It has been commonly accepted that the lacrimal fascia is an intact septum, composed of connective tissue, that separates the orbital cavity into a large compartment, which contains the eyeball, and a small compartment, which contains the lacrimal sac and nasolacrimal duct. the septum, however, is not necessarily always intact. We found a circular or oval opening in the lacrimal fascia in 37 of 52 specimens (71.2%) examined. The opening, which we shall refer to as the lacrimal fascial foramen, was located at variable levels in the lacrimal fossa. The lacrimal fascial foramen was buried in fatty tissue through which passed a branch of either the inferior palpebral artery or the infraorbital artery and a vein of the nasolacrimal duct. The clinical implications of the lacrimal fascial foramen in obstruction of the nasolacrimal duct are discussed.

Aged↗

PubMed2001

Deficit in motor cortical activity for simultaneous bimanual responses.

Reaction time (RT) is known to be longer for simultaneous bimanual responses than for unimanual ones. This phenomenon is called "bilateral deficit". To identify the mechanisms subserving the bilateral deficit, brain electrical activity was examined, with a source derivation method, in 12 right-handed subjects, during the preparation and execution periods of a RT task. The responses were either unilateral or bilateral index finger flexion, performed either in a simple RT condition, with 20% catch trials, or in a choice RT condition. A deficit was observed in RT for the bilateral response for the right-index finger movement. In cerebral electrical activities, no evidence of a correlate of a bilateral deficit was found during the preparatory period. Conversely, during the execution period, an EEG correlate of the bilateral deficit was found. For the right hand, the activation of the sensorimotor area directly involved in the voluntary control was weaker for bilateral than for unilateral contralateral responses. The reasons for such a bilateral command weakness are discussed in the context of our RT task. First, the constraint of synchronisation included in the bilateral response might require an interhemispheric information transmission that resulted in a braking effect. Second, given that an ipsilateral inhibition is present in case of choice between the two hands of one particular unimanual response, and given that this ipsilateral inhibition is also present in case of simple unimanual trials, we hypothesise that a mutual transcallosal inhibitory effect also persists in the bilateral response.

Adult↗

PubMed2001

Mitoses of existing corticotrophs contribute to their proliferation in the rat pituitary during the late fetal period.

We studied the proliferation of pituitary corticotrophs quantitatively by labeling the proliferating cells with bromodeoxyuridine (BrdU) and carrying out immunocytochemistry for ACTH in rat fetuses at 19.5 days of gestation. In addition to labeling proliferating cells with a single injection of BrdU, we used double BrdU administrations at 9:00 and 19:00 for a more sensitive detection of proliferating cells. With this double administration, the number of cells labeled with either BrdU or both BrdU and ACTH increased by 1.75 and 2.3 times, respectively, compared with the single BrdU injection. The labeled cells further increased when the sections were stained for the proliferating cell nuclear antigen (PCNA) instead of BrdU. The number of cells labeled with PCNA or both PCNA and ACTH was 1.37 and 1.68 times that of the cells labeled with either BrdU or both BrdU and ACTH, respectively. The ratio of BrdU/ACTH-labeled cells or PCNA/ACTH-labeled cells to all corticotrophs was 13.6% and 24.3%, respectively, much higher than the ratios in fetuses having a single BrdU injection (6.6%). These results indicate that the mitosis of existing corticotrophs contributes greatly to their increase during the late fetal period.

Adrenocorticotropic Hormone↗

PubMed2001

Proliferation and differentiation of thyrotrophs in the pars distalis of the rat pituitary gland during the fetal and postnatal period.

Pituitary glands from rat fetuses (gestational age 17.5-21.5 days) and rat pups (3, 7, 10, 14, 28 days old) were labeled with bromodeoxyuridine (BrdU) 2 h prior to sacrifice and embedded in paraffin. Sections were consecutively immunostained with anti-BrdU and anti-rat TSH. The number of cells stained with anti-BrdU, anti-rTSH, or both of them were counted. The area of the section and the volume of the pituitary were measured and the number of immunostained cells per mm3 or per pituitary was calculated. Thyrotrophs were few in 17.5 day-fetuses but increased thereafter, with a rapid increase during the 2nd week after birth. The number of cells labeled with both BrdU and TSH peaked at 7 days after birth. It was estimated that about 1/5 of the thyrotrophs increased during this period was derived from the mitosis of existing thyrotrophs.

Aging↗

PubMed2001

Proliferation and differentiation of pituitary somatotrophs and mammotrophs during late fetal and postnatal periods.

Proliferation of somatotrophs and mammotrophs in the rat pituitary during late fetal and postnatal periods up to 4 weeks after birth was quantitatively studied with the double immunostaining of bromodeoxyuridine and the hormones produced by them. Somatotrophs were first detected in 18.5-day fetuses and rapidly increased in number throughout the periods studied. The cells labeled with both anti-BrdU and anti-GH were few in number until shortly before birth and then increased conspicuously during the first 10 days after birth. Mammotrophs were detected at gestational day 19.5 but they were few until the second week after birth, when their number began to increase rapidly. The percentage of the number of the cells double-labeled with both anti-BrdU and anti-GH to all somatotrophs was 8.3% at the most. This was about the same as that of corticotrophs during the late fetal period and that of thyrotrophs in the early postnatal period. In contrast, the percentage of double-labeled cells to all mammotrophs was 3.8% as a maximum, which is lower than the values for somatotrophs, corticotrophs, or thyrotrophs, indicating a smaller contribution of mitosis to mammotroph proliferation. It is possible that this smaller contribution is compensated for by transdifferentiation of cells committed to become the somatotroph lineage. However, coexistence of GH and PRL was not observed in the present material.

Animals↗