Biomedical subjects

A Sakai

Publications and source records attributed to A Sakai.

At least 91 records · Page 5Linked to original sources

PubMed1999

Two types of ftsZ genes isolated from the unicellular primitive red alga Galdieria sulphuraria.

FtsZ plays a crucial role in bacterial cell division, and may be involved in plastid division in eukaryotes. To investigate the evolution of the dividing apparatus from prokaryotes to eukaryotes, the ftsZ genes were isolated from the unicellular primitive red alga Galdieria sulphuraria. Two ftsZ genes (GsftsZ1 and GsftsZ2) were isolated. This suggests that duplication and divergence of the ftsZ gene occurred in an early stage of plant evolution. A comparison of the FtsZs of G. sulphuraria and other organisms shows that FtsZ is highly and universally conserved among prokaryotes, primitive eukaryotic algae, and higher plants. The GsftsZ2 gene seems to contain an intron. Southern hybridization analysis of the G. sulphuraria chromosomes separated by CHEF revealed that each ftsZ gene and its flanking region may be duplicated.

Amino Acid Sequence↗

PubMed1999

Auxin and cytokinin have opposite effects on amyloplast development and the expression of starch synthesis genes in cultured bright yellow-2 tobacco cells.

In cultured Bright Yellow-2 (BY-2) tobacco (Nicotiana tabacum) cells, the depletion of auxin (2,4-dichlorophenoxyacetic acid) in the culture medium induces the accumulation of starch. This is accelerated by the addition of cytokinin (benzyladenine). Light and electron microscopic observations revealed that this amyloplast formation involves drastic changes in plastid morphology. The effects of auxin and cytokinin on amyloplast development were investigated by adding auxin or cytokinin to cells grown in a hormone-free culture. Auxin repressed amyloplast development, whereas cytokinin accelerated starch accumulation regardless of the timing of hormone addition. RNA gel-blot analysis revealed that the accumulation of the ADP-glucose pyrophosphorylase small subunit gene (AgpS), granule-bound starch synthase, and starch branching enzyme transcripts were also affected by hormonal conditions. High levels of AgpS, granule-bound starch synthase, and starch branching enzyme transcripts accumulated in amyloplast-developing cells grown in auxin-depleted conditions. Furthermore, the addition of auxin to the cells cultured in hormone-free medium reduced the level of AgpS transcripts, whereas the addition of cytokinin increased it, irrespective of the timing of hormone addition. These results suggest that auxin and cytokinin exert opposite effects on amyloplast development by regulating the expression of the genes required for starch biosynthesis.

1,4-alpha-Glucan Branching Enzyme↗

PubMed1999

[Investigation of a new p24 antigen detection system by the chemiluminescence-enzyme-immuno-assay].

We investigated a new p24 antigen detection system by the chemiluminescence-enzyme-immuno-assay (CLEIA) and compared it with the conventional antigen-kits (A; Abbott, B; Coulter). The detection limit of CLEIA, A, and B were 4.3 pg/ml, 11.3 pg/ml, and 5.6 pg/ml, respectively. When the patient's sera and panel sera were examined by the three method, compatible results with the detection limit were obtained. CLEIA can be completed within 35 min, and is performed by an automatic system, which can treat many samples at one time. Therefore, this system is more suitable for screening of donor blood because of the shortening of the window period.

Enzyme-Linked Immunosorbent Assay↗

PubMed1999

AS-924, a novel orally active bifunctional prodrug of ceftizoxime. Synthesis and relationship between physicochemical properties and oral absorption.

Ceftizoxime (CZX), a parenteral cephalosporin, has potent and broad antibacterial activity. To improve its oral absorption, we synthesized a series of monofunctional and bifunctional prodrugs of CZX. In rabbits, urinary recovery after oral administration of CZX was improved by esterification of the carboxyl group at the C-4 position with various lipophilic moieties (monofunctional prodrugs), and was further increased by introduction of a hydrophilic L-alanine to the amino group on the thiazole ring at the C-7 position (bifunctional prodrugs). Least-squares analysis showed good parabolic correlations between log P and urinary recovery for monofunctional and bifunctional prodrugs, respectively. AS-924, a bifunctional prodrug with a pivaloyloxymethyl and L-alanyl moiety had the best balance of lipophilicity and water-solubility for oral absorption among the prodrugs synthesized.

Administration, Oral↗

PubMed1999

Intermittent administration of human parathyroid Hormone(1-34) prevents immobilization-related bone loss by regulating bone marrow capacity for bone cells in ddY mice.

ddY mice, 6 weeks of age, were neurectomized (Nx) in the right hindlimbs and sham-operated (Sham) in the left limbs for evaluation of the effects of intermittent injections of human parathyroid hormone (hPTH) on trabecular bone turnover and bone marrow cell development in unloaded and loaded limbs. Mice were given subcutaneous injections of hPTH(1-34) five times a week at a dose of 0 (vehicle), 4 (low dose), or 40 (high dose) microg/kg of body weight for 2, 4, or 6 weeks. Histomorphometric analyses of the trabecular bone of the proximal tibiae revealed that high-dose hPTH injections preserved the trabecular bone volume of the Nx limbs, which was reduced after neurectomy, at the same level as that of the contralateral Sham limbs. The mineral apposition rate in the Nx limbs was elevated to values above even that of the Sham limbs by high-dose hPTH injections. The bone formation rate reduced by neurectomy was maintained at the Sham level by low- and high-dose hPTH injections. The neurectomy-induced increase in osteoclast number was suppressed by high-dose hPTH injections. In the bone marrow cells, the numbers of nonadherent and adherent cells per tibia obtained from the Nx and Sham limbs did not change. The hPTH injections decreased the numbers of nonadherent cells and increased those of adherent cells in both the Nx and the Sham limbs, but the effects were less marked in the Nx than in the Sham limbs even at high-dose injections. The formation of osteogenic nodules in the marrow cultures obtained from the Nx limbs was decreased after surgery and was maintained at the level of the Sham limbs by high-dose hPTH injections. The number of osteoclast-like multinucleated cells was reduced in the Sham limbs by high-dose hPTH injections. The value was increased at 2 weeks after neurectomy, but it was maintained at the Sham level by high-dose hPTH injections through the experimental period. The numbers of colony forming units-fibroblastic, which were reduced by neurectomy, and those of colony forming units for granulocytes and macrophages were not altered by hPTH injections. These results demonstrate that intermittent high-dose hPTH administration in the Nx limbs as well as in the contralateral Sham limbs has similar anabolic effects, stimulating osteoblast cell lineage and suppressing osteoclast cell lineage. The anabolic effects at 4 microg were reduced, but the effects at 40 microg seemed to be less affected by unloading due to sciatic neurectomy.

Animals↗

PubMed1999

Trabecular bone turnover and bone marrow cell development in tail-suspended mice.

To clarify the relationship between the changes of trabecular bone turnover and bone marrow cell development during mechanical unloading and reloading, we performed experiments with tail-suspended mice. At 8 weeks of age, 150 male ddY mice were divided into three body weight-matched groups. Mice of group 1 were euthanized at the start of tail suspension (day 0) as a baseline control. The mice of group 2 were subjected to hindlimb unloading by tail suspension for 14 days and reloading for the subsequent 14 days. The mice of group 3 were normally loaded as age-matched controls. Mice of groups 2 and 3 were sacrificed at 7, 14, and 28 days after the start of the experiment. In the first experiment (histomorphometric study of tibiae), unloading for 7 and 14 days and reloading for the subsequent 14 days significantly decreased the bone volume compared with that in the age-matched controls, respectively. Unloading for 7 and 14 days also significantly reduced the bone formation rate (BFR/BS), respectively, but reloading for the subsequent 14 days restored BFR/BS to the control level. While the unloading for 7 and 14 days significantly increased both the osteoclast surface (Oc.S/BS) and the osteoclast number (Oc.N/BS), the reloading for the subsequent 14 days decreased Oc.S/BS and Oc. N/BS, respectively. In the second experiment (bone marrow cell culture study of tibiae), unloading for 7 and 14 days reduced the adherent stromal cell number, without significance. Unloading for 7 days significantly decreased the mineralized nodule formation. Reloading for the subsequent 14 days markedly increased the adherent stromal cell number and the mineralized nodule formation. Unloading for 7 days significantly increased the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. These data clearly demonstrate that unloading reduces bone formation and increases bone resorption, and subsequent reloading restores reduced bone formation and suppresses increased bone resorption, closely associated with the changes in adherent stromal cell number, mineralized nodule formation, and the number of TRAP-positive multinucleated cells.

Animals↗

PubMed1999

Induction of ovulation by Sairei-to for polycystic ovary syndrome patients.

In anovulatory patients ovulation is usually induced by clomiphene citrate (CC) or gonadotropin therapy, but in the case of polycystic ovary syndrome (PCOS), diagnosed by the presence of several micropolycysts in the ovaries and a high LH/FSH ratio in the serum, CC is only minimally effective, and side effects are often a problem with gonadotropin therapy. In the present study we administered a Chinese herbal medicine Sairei-to which appears to have a steroidal effect in anovulatory PCOS patients. As a result of the treatment, serum LH and the LH/FSH ratio significantly decreased (P<0.01) and the ovulatory rate was 70.6%. Serum testosterone levels were within normal limits before the treatment, and did not significantly change during the treatment. Sairei-to may therefore be useful for the treatment of anovulation in PCOS patients.

Anovulation↗

PubMed1999

Improved sensitivity for high resolution in situ hybridization using resin extraction of methyl methacrylate embedded material.

An in situ hybridization procedure resulting in both high resolution and sensitivity was established by using the removable methyl methacrylate resin, Technovit 9100. Young bicellular pollen of tobacco (Nicotiana tabacum L. SR-1) was embedded in Technovit 9100 resin and sectioned. The resin was extracted with (2-methoxyethyl)-acetate followed by in situ hybridization with cRNA probes to detect cytoplasmic 18S/25S rRNA. Signal intensity obtained by this procedure was approximately twice as great as that obtained by an earlier procedure using Technovit 7100, a glycol methacrylate resin that cannot be removed from sections. This improvement in sensitivity made it possible to observe subcellular localization of small amounts of RNA as revealed by visualization of plastid 23S rRNA in a generative cell of Plumbago auriculata pollen.

Acetates↗

PubMed1999

[Development of the Japanese version of the Buss-Perry Aggression Questionnaire (BAQ)].

The Aggression Questionnaire (Buss & Perry, 1992) has been used to investigate links between personality factors and health outcomes. We developed the Japanese version of the Buss-Perry Aggression Questionnaire (BAQ) and assessed validity and reliability of the scale. Study I (N = 1,125 college students) used a 45-item rating questionnaire measuring each of four components of aggression: Anger, Hostility, Physical Aggression, and Verbal Aggression. Four aggression subscales emerged clearly from exploratory factor analysis. Study II (N = 611 college students) used a 24-item questionnaire and replicated factor structure and factor loadings of Study I. The scales were shown to be highly internally consistent, and stable at appropriate levels over 4-month time period. Normative data, factorial validity, and external evidence of construct, convergent, and discriminant validity for the scales were also presented.

Adult↗

PubMed1999

[Survey of combined spinal-epidural anesthesia in Japan--analysis of questionnaire from 148 hospitals].

Combined spinal-epidural anesthesia (CSEA) offers theoretic advantages especially for lower abdominal and limb surgery, because it produces the rapid onset of anesthesia and the proper muscle relaxation, with the option to extend the blockade with an epidural catheter. Whereas it is not known whether this anesthetic method is commonly used in clinical practice in Japan. We analyzed questionnaires on CSEA obtained form 148 hospitals. It was revealed that most anesthesiologists in Japan preferred general anesthesia with epidural block for lower abdominal surgery to CSEA. For lower limb surgery longer than 2 hrs, CSEA was employed in 57 hospitals (39%). CSEA was mainly used for orthopedics, obstetrics and gynecology and urology. Double needle double interspace method was commonly used rather than needle through needle method. In general, CSEA was not a widely performed anesthetic technic in Japan. CSEA should contribute to reduction of the incidence of postoperative nausea and vomiting caused by general anesthetics, and produce pre-emptive analgesia. We hope CSEA to be a common anesthetic procedure, although some disadvantages exist in training system for junior staff, national health insurance scheme and available local anesthetics in Japan.

Abdomen↗

PubMed1999

[Propofol anesthesia for a patient with congenital myotonic dystrophy].

We report the anesthetic management for a five year old boy with congenital myotonic dystrophy. The patient was scheduled for bilateral orchiopexy under general anesthesia. Anesthesia was induced with fentanyl 50 micrograms, vecuronium 0.6 mg and propofol 40 mg intravenously to facilitate tracheal intubation. During operation, we monitored train of four ratio (TOF) to confirm effect of muscle relaxation. Anesthesia was maintained with propofol (2 mg.kg-1.hr-1), nitrous oxide and caudal block. At the end of the operation, the patient recovered smoothly from anesthesia and post-operative course was uneventful. Congenital myotonic dystrophy presents many problems for the management of general anesthesia, because of respiratory or circulatory complications. In this case, we were careful not to use drugs which may cause respiratory or circulatory depression. We have demonstrated that anesthesia with propofol is a safe method for the anesthetic management of a patient with this disease.

Anesthesia, General↗

PubMed1998

PTEN gene alterations in lymphoid neoplasms.

Recently, a novel phosphatase designated PTEN/MMAC1/TEP1 and located on chromosome 10q23.3 has been implicated as a new tumor suppressor gene in human cancer. Allelic loss and mutation of this gene has been reported in epithelial derived tumors, including breast cancer and prostate cancer, and in glioblastoma multiforme. The present study was designed to evaluate the potential involvement of PTEN in the pathogenesis of lymphoid neoplasms. We analyzed 27 hematopoietic cell lines (representing a variety of lymphoid lineages), 65 primary lymphoid tumors (including 24 lymphoblastic leukemia/lymphoma [LBL], 30 large B-cell lymphoma [LBCL], 7 Burkitt's lymphoma [BL], and 4 anaplastic large cell lymphoma [ALCL]), and 25 nonmalignant lymph node controls. Gene deletion and gross rearrangement were evaluated using Southern blot analysis, and mutations were studied by polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) (PCR-SSCP) and sequencing. Six of 27 cell lines (22.2%) and 3 of 65 primary lymphomas (4.6%) contained alterations of this gene. A large homozygous deletion spanning exons 2 through 5 was detected in one LBL cell line, and two insertions potentially resulting in premature termination, were detected in a second LBL cell line. Nonconservative nucleotide variations were found in two other cell lines (one LBCL and one BL) and in one primary case of LBCL. In addition, two other cell lines (one BL and one myeloma) and two primary lymphomas, both LBCL, contained small deletions within intron 7. These deletions mapped to a poly-T-rich tract just 5' to the intron 7/exon 8 spice site. Their significance is unclear, as they may represent polymorphisms. Overall, our results suggest that abnormalities of the PTEN gene can contribute to pathogenesis in a small percentage of malignant lymphomas.

Cell Transformation, Neoplastic↗

PubMed1998

Expressions of p53 and PCNA do not correlate with the international index or early response to chemotherapy in non-Hodgkin's lymphoma.

The expression of p53 and PCNA on deparaffinized sections of tumor was assessed in relation to the International Index and response to chemotherapy. Thirty-five non-Hodgkin's lymphoma (NHL) patients were divided into three groups: aggressive NHL, mantle cell lymphoma (MCL), and low-grade NHL. None of the expressions correlated with the International Index or early response to chemotherapy in any group. In low-grade NHL, none of the patients expressed p53. Only one of three patients with overexpression of p53 showed conformational change and alteration of sequence in exon 7 by PCR-SSCP and DNA sequencing. The results showed that p53 and PCNA staining were not useful for predicting early response to chemotherapy, and that their expressions had no correlation with the International Index.

Adult↗

PubMed1998

Painful junctura tendinum of the hand extensors.

A case of painful junctura tendinum of the hand extensors is presented. This rare condition may have developed because of anatomical factors, including the type of connection and location of the junctura, and because of the unique position that the fingers assume during bowling.

Adult↗

PubMed1998

Three-dimensional analysis of the senescence program in rice (Oryza sativa L.) coleoptiles. Investigations of tissues and cells by fluorescence microscopy.

The coleoptile of rice (Oryza sativa L. cv. Nippon-bare) emerges from an imbibed seed on day 2 after sowing. Then, it matures and senesces rapidly. For analysis of the senescence pattern within individual coleoptiles, we monitored the distribution of chlorophyll (Chl) in entire coleoptiles and in cross-sections of coleoptiles by recording the autofluorescence of Chl. Degradation of Chl was apparent at the tip of the margins of opened-out coleoptiles on day 4, when the overall levels of soluble protein and Chl per coleoptile had reached maximum values. Then, senescence proceeded from the tip to the base and from the inner mesophyll cells towards the outer epidermis, excluding tissues along vascular bundles. Further analysis of cellular senescence using samples embedded in Technovit 7100 resin revealed that the senescence of each green mesophyll cell followed an identical program, which consisted of the following steps: (i) degradation of chloroplast DNA; (ii) condensation of the nucleus, decrease in the size of chloroplasts, degradation of ribulose-1,5-bisphosphate carboxylase/oxygenase and chloroplast inner membranes; (iii) disorganization of the nucleus; (iv) complete loss of cellular components, distortion of the cell wall. Although the timing of each step and the rate at which each step was completed differed among cells of different locations within the coleoptile, this sequence was observed in all mesophyll cells in the coleoptile.

Cotyledon↗

PubMed1998

The division apparatus of plastids and mitochondria.

Mitochondria and plastids in eukaryotic cells contain distinct genomes and multiply in the cytoplasm by binary division of preexisting organelles. Mitochondrial and plastid nuclei are easily visualized as compartments in the matrix of organelles by high-resolution fluorescence microscopy and by immunoelectron microscopy using anti-DNA antibodies. Plastid and mitochondrial division can be clearly separated into two main events: division of the organelle nuclei, and then division of the rest of the organelles, the process of organellokinesis (mitochondriokinesis and plastidokinesis). The mechanical apparatus that regulates organellokinesis has remained undetermined. In 1986, the plastid-dividing apparatus (PD ring) for plastidokinesis was first identified by us in the primitive red alga Cyanidium caldarium RK-1. The PD ring is located in the cytoplasm outside the organelle envelope at the constricted isthmus of dividing organelles and has subsequently been found in all eukaryotic plants examined. We were also the first to identify the mitochondrion-dividing apparatus (MD ring) for mitochondriokinesis in the unicellular red alga Cyanidioschyzon merolae in 1993. Eukaryotic cell division is therefore controlled by at least three dividing apparata (rings), a contractile ring, an MD ring, and a PD ring, while bacterial division is controlled by a single bacterial contractile FtsZ ring. The aims of this review are to present the fine structure, process of formation, and contraction of the organelle-dividing apparatus, focusing on evolutionary conservation and diversion from the bacterial contractile ring.

Cell Division↗

PubMed1998

Fibroblast-migration in a wound model of ascorbic acid-supplemented three-dimensional culture system: the effects of cytokines and malotilate, a new wound healing stimulant, on cell-migration.

To assess the migratory response of fibroblasts in vitro, normal human dermal fibroblasts (NHDF) were cultured in the presence of L-ascorbic acid 2-phosphate to induce a multilayered structure. Round wounds were made by punching, and the migratory response was evaluated by counting the number of migrating cells in the wounded areas. Collagenase activity in the culture-medium was then measured. When the wound model was treated with bFGF, IL-1 alpha or PDGF, the migratory response was facilitated with increased collagenase secretion. In contrast, treatment with TGF-beta reduced the migratory response and collagenase secretion. Since the multilayered structure is rich in collagenous matrix, degradation of the matrix by secreted collagenase is probably necessary for the cells to migrate into the wounded areas. Furthermore, malotilate, which is now under development as an agent for wound therapy, facilitated the migratory response of NHDF with increased collagenase secretion in this wound model, suggesting that the wound healing effect of malotilate is in part attributable to stimulated migration of fibroblasts to wounded areas subsequent to extracellular matrix-degradation.

Ascorbic Acid↗

PubMed1998

Effects of a weekly injection of human parathyroid hormone (1-34) and withdrawal on bone mass, strength, and turnover in mature ovariectomized rats.

One hundred fifteen Wistar rats, 7 months of age, were ovariectomized (ovx) or sham-operated to evaluate the effects of a weekly injection of human parathyroid hormone (hPTH) and withdrawal on the bone mass, strength, and turnover in mature ovariectomized rats. At 3 months, ovx rats were given a weekly injection of hPTH(1-34) at the respective doses of 0 (vehicle), 10, and 90 microg/kg body weight (BW) for 3 months. Then, hPTH-treated rats were divided into two groups each: continuously treated groups, and the groups treated with vehicle only for another 3 months. Weekly hPTH injections at doses of 10 or 90 microg/kg BW maintained the lumbar BMD values and increased the values of the femoral cortical bone, increasing the bone formation rates in the trabecular, endocortical, and periosteal envelopes. Trabecular osteoclasts were increased in the 90 microg/kg dose group. Trabecular bone surface relative to the volume was decreased by hPTH. The compressive load of the lumbar bone and the bending moment of the midfemur were increased. The lumbar compressive load values, corrected for BMD and volume, and the moment of inertia of the midfemur were also increased. The intracortical porosity values were not increased by the treatment. After withdrawal of hPTH treatment, the BMD values in both the lumbar and the midfemur were reduced to ovx control levels. The bone mass stimulated by the 90 microg/kg dose was reduced faster than that by the 10 microg/kg dose. However, the parameters of bone strength were still larger than those of the ovx controls after cessation of the hPTH treatment. Thus, a weekly hPTH injection effectively stimulated the bone formation in both the trabecular and cortical bone, leading to positive effects on mass and structure of the bone. These data suggest the possibility of benefits of both a lower frequency of hPTH injections as well as high-frequency injections for human osteoporotics.

Absorptiometry, Photon↗