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Biomedical subjects

T Wakayama

Publications and source records attributed to T Wakayama.

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

Hodgkin's disease preceded by unique neurological symptoms.

This is the first case report of Hodgkin's disease (HD) which showed both remission and exacerbation of neurological signs before a confirmed diagnosis of HD. The episodes occurred three times and multiple lesions were involved. Immunoabsorption plasmapheresis and double filtration plasmapheresis were effective for the first episode, whereas, corticosteroids partly improved the second and third episodes. Fever and lymph node swelling were apparent afterward and she was diagnosed as having HD from a supraclavicular lymph node biopsy. The remaining neurologic deficits responded to chemotherapy and radiotherapy. The neurological symptoms were considered as a paraneoplastic syndrome of HD.

Adult↗
PubMed2001

Protein expression and cell organelle behavior in spermatogenic cells.

Spermatogenic cells stage-specifically produce a wide variety of proteins during spermatogenesis, wherein protein expression is coordinated with cell organelle behavior. It has been shown that the Golgi apparatus and the endoplasmic reticulum (ER) are uniquely coordinated with the expression of an immunoglobulin super-family protein, flagellar plasma membrane MC31 (MC31/CE9), and a molecular chaperone, calmegin, respectively. When the Golgi apparatus begins to generate sperm components in the primary spermatocytes, it actively engages in producing proteins for the acrosome in round spermatids and for the flagellum in elongating spermatids. Structurally, the Golgi apparatus is reduced in size during meiotic division, moves from the apical to the basal region (cytoplasmic lobe) when spermatids differentiate from round to elongating phase, and then collapses in the late maturation phase. The ER is distributed uniformly over the entire cytoplasm of spermatocytes and round spermatids, and then moves distally toward the cytoplasmic lobe along the bundles of microtubule, called the manchette, in elongating spermatids. The ER is resorbed into the radial body in late maturation spermatids. MC31/CE9 expresses strong immunostaining twice on the Golgi apparatus during spermatogenesis, first in early pachytene spermatocytes and then in early elongating spermatids. Calmegin expression exactly parallels ER behavior. This mini-review focuses on the unique relationships in spermatogenic cells, particularly those between protein expression and cell organelle behavior.

Acrosome↗
PubMed2000

Zeta-crystallin catalyzes the reductive activation of 2,4,6-trinitrotoluene to generate reactive oxygen species: a proposed mechanism for the induction of cataracts.

Exposure to 2,4,6-trinitrotoluene (TNT) has been shown to cause induction of cataract in which oxidative stress plays a critical role. From bovine lens we purified to homogeneity and identified an enzyme that catalyzes the reduction of TNT, resulting in the production of reactive oxygen species. The final preparation of TNT reductase showed a single band with a subunit molecular weight of 38 kDa on SDS-PAGE. Sequence data from peptides obtained by digestion with lysylendopeptidase Achromobacter protease I (API) revealed that TNT reductase is identical to zeta-crystallin. Superoxide anions were formed during reduction of TNT by zeta-crystallin, though negligible enzyme activity or protein content for superoxide dismutase, a superoxide scavenging enzyme, was found in the lens. Thus, the present results suggest that the induction of cataracts by TNT may be associated with increased oxidative stress, as a result of reductive activation of TNT generating superoxide anions, there being minimal antioxidant enzyme activity for defense against reactive oxygen species exogenously produced in the lens.

Amino Acid Sequence↗
PubMed2000

Mammalian oocyte activation by the synergistic action of discrete sperm head components: induction of calcium transients and involvement of proteolysis.

Sperm-borne oocyte-activating factor (SOAF) elicits activation sufficient for full development and originates from sperm head submembrane matrices. SOAF comprises discrete, heat-sensitive and -stable components (referred to here respectively as SOAF-I and -II) which are each necessary but not sufficient to activate oocytes. The heat-sensitive SOAF component, SOAF-I(m), becomes solubilized from the perinuclear matrix under reducing conditions (the SOAF transition) to generate SOAF-I(s). Although calcium transients likely play an important role in oocyte activation at fertilization, the question is open as to whether demembranated heads or SOAF-I(s) and/or SOAF-II can induce calcium transients. We now report that injection of demembranated sperm heads into mouse oocytes efficiently induced Ca(2+) oscillations. When injected independently, SOAF-I(s) and demembranated heads heated to 48 degrees C failed to generate Ca(2+) oscillations. However, co-injection of SOAF-I(s) and 48 degrees C-heated heads induced oscillations, mirroring their synergistic ability to activate oocytes. This suggests that SOAF-mediated activation proceeds via pathways resembling those at fertilization and provides the first direct evidence that multiple sperm components are required to induce Ca(2+) oscillations. We probed the SOAF-I(s) liberation at the center of this activation and show that in vitro it was sensitive to a profile of serine protease inhibitors. These findings support a model in which mammalian oocyte activation, including the induction of calcium transients, involves proteolytic processing of SOAF from sperm head submembrane compartments.

Animals↗
PubMed2000

Birth of mice after nuclear transfer by electrofusion using tail tip cells.

Mice have been successfully cloned from cumulus cells, fibroblast cells, embryonic stem cells, and immature Sertoli cells only after direct injection of their nuclei into enucleated oocytes. This technical feature of mouse nuclear transfer differentiates it from that used in domestic species, where electrofusion is routinely used for nuclear transfer. To examine whether nuclear transfer by electrofusion can be applied to somatic cell cloning in the mouse, we electrofused tail tip fibroblast cells with enucleated oocytes, and then assessed the subsequent in vitro and in vivo development of the reconstructed embryos. The rate of successful nuclear transfer (fusion and nuclear formation) was 68.8% (753/1094) and the rate of development into morulae/blastocysts was 40.8% (260/637). After embryo transfer, seven (six males and one female; 2.5% per transfer) normal fetuses were obtained at 17.5-21.5 dpc. These rates of development in vitro and in vivo are not significantly different from those after cloning by injection (44.7% to morulae/blastocysts and 4.8% to term). These results indicate that nuclear transfer by electrofusion is practical for mouse somatic cell cloning and provide an alternative method when injection of donor nuclei into recipient oocytes is technically difficult.

Animals↗
PubMed2000

Postnatal growth and behavioral development of mice cloned from adult cumulus cells.

Since the first successful cloning of mammals from adult somatic cells, there has been no examination of the learning or behavior of cloned offspring. The possibility of adverse effects on animals produced through adult somatic cell cloning is high because many natural biological processes are bypassed and DNA from adult cells, which presumably contain mutations, are used. In this study, we compared cloned mice produced by microinjection transfer of cumulus cell nuclei into enucleated oocytes, to control mice that were specifically generated to eliminate confounding factors that are unique to our cloning procedure. Postnatal weight gain of clones was significantly greater than that of controls. Preweaning development observations revealed that first appearance or performance of 3 out of 10 measures was delayed in cloned mice; however, results of subsequent tests of learning and memory, activity level, and motor skills were comparable for both groups. Together, these data suggest that nuclear transfer of adult somatic cell nuclei to produce cloned mice may delay the appearance of a few developmental milestones but it does not adversely affect the overall postnatal behavior of mice. In addition, this procedure may cause late onset of significantly increased body weight in cloned offspring, the cause or causes of which are being further examined.

Animals↗
PubMed2000

Enzymatic reactivity and anti-tumor activity of 1-(beta-D-arabinofuranosyl)-2-thiocytosine derivatives.

Sixteen derivatives of 1-(beta-D-arabinofuranosyl)-2-thiocytosine (araSC), including five 5'-esters, three 3'-esters, five N4-amides and three 5'-phosphodiesters, were synthesized and their reactivity to mouse tissue homogenates, including plasma, liver and intestine, and antitumor activity in mice bearing P388 cells were measured. The ester derivatives had a potent effect on the enzyme systems while the amide and phosphodiester derivatives were less active. The reactivity of ester derivatives was highly dependent on their chemical structure. The reactivity of amides and phosphodiester derivatives on mouse plasma and intestinal homogenate was also dependent on the chemical structure, although their action on intestinal enzymes was very similar. Two of eight ester derivatives showed considerable antitumor activity in vivo, although they also showed serious toxicity indicated by a weight loss in the mice. Four out of five amides and two out of three phosphodiesters showed antitumor activity, and two were highly effective (>200% in T/C, the ratio of the mean survival time of the treated group to that of the control group) with only a very slight weight loss.

Animals↗
PubMed2000

Effect of light/dark cycle on bacterial hydrogen production by Rhodobacter sphaeroides RV. From hour to second range.

Hydrogen production by photosynthetic bacteria provides an efficient energy conversion method under low light intensity. However, under strong illumination, such as midday sunlight, the efficiency drops. This prevents the method from being applied industrially. To overcome this problem, we examined a method to thin out the excessive illumination. Light was given intermittently to reduce the total energy flux. The on/off ratio was set at 1/1 throughout the study, so that the time average of the light energy flux became half the continuous illumination. By keeping the time-average light flux constant (0.6 kW.m-2), the effects of the cycle period were examined in the range of hours to seconds. The hydrogen production rate was greatly affected by the cycle period, but cell growth and substrate consumption rates remained almost constant. The 30-min light/dark cycle (30 min on and 30 min off) provided the highest rate of hydrogen production (22 L.m-2.24 h-1). At the shorter cycles, the rate decreased except that there was a suboptimum at about 40 s. Under excessive light intensity (1.2 kW.m-2), the light-to-hydrogen conversion efficiency was greatly enhanced. The hydrogen production rate during the 30-min cycle was twice as high as during a 12-h cycle under the same conditions.

Activity Cycles↗
PubMed2000

The expression and cellular localization of the sperm flagellar protein MC31/CE9 in the rat testis: possible posttranscriptional regulation during rat spermiogenesis.

We isolated the MC31 cDNA clone coding the antigen specifically recognized by the monoclonal antibody mMC31, and found that MC31 was identical to rat CE9. Therefore, this molecule is called MC31/CE9. MC31/CE9, a member of the immunoglobulin superfamily molecules, was localized on the rat sperm flagellar plasma membrane. We analyzed the expression and cellular localization of MC31/CE9 mRNA and protein in the adult rat testis by use of Northern hybridization, in situ hybridization, and immunohistochemical analyses. In the course of spermatogenesis, MC31/CE9 mRNA first appeared in type B spermatogonia. The mRNA signal intensity increased progressively to pachytene spermatocytes and remained constantly at a considerable level throughout the subsequent phases of spermatocytes and round spermatids, and then decreased gradually from step-11 spermatids to disappear in step-15 spermatids. On the other hand, MC31/CE9 protein expression showed a bimodal pattern. Immunohistochemical analysis for the MC31/CE9 protein revealed its most intense immunoreactivity on the flagella of step-8 to step-19 elongated spermatids. The cytoplasmic immunoreactivity of the MC31/CE9 protein also appeared in preleptotene to early pachytene spermatocytes and elongated spermatids, with particularly intense immunoreactivity in the Golgi complexes of zygotene and early pachytene spermatocytes (stage XIII to III) as well as step-8 to step-13 spermatids. Between these two phases, the MC31/CE9 protein proved undetectable in the cytoplasm of any spermatogenic cells. Sertoli cells and Leydig cells were devoid of MC31/CE9 mRNA and its protein. Therefore, the production of MC31/CE9 is thought to be posttranscriptionally regulated during spermiogenesis.

Animals↗
PubMed2000

[Empyema thoracis accompanied by hyperammonemic encephalopathy].

A 50-year-old man was admitted to our hospital due to consciousness disturbance. On admission, he was comatose (200 on the Japan Coma Scale) but brain computed tomographic (CT) scans were normal. Chest radiographs and CT scans on admission revealed massive pleural effusion in the right hemithorax. A culture of purulent pleural fluid yielded three species of anaerobes, including Bacteroides fragilis. Laboratory examinations revealed markedly elevated WBC count, CRP, and serum ammonia (586 micrograms/dl). However, liver function was almost normal and no other metabolic disorders were demonstrated. After the initiation of antibiotic therapy and pleural drainage, the patient's cousciousness level gradually improved in parallel with decreasing serum levels of ammonia and CRP. Because no other potential causes of hyperammonemia were observed, we concluded that the consciousness disturbance was due to hyperammonemia presumably caused by a urease-producing anaerobe infecting the right pleural space.

Ammonia↗
PubMed1999

Mice cloned from embryonic stem cells.

Cloning allows the asexual reproduction of selected individuals such that the offspring have an essentially identical nuclear genome. Cloning by nuclear transfer thus far has been reported only with freshly isolated cells and cells from primary cultures. We previously reported a method of cloning mice from adult somatic cells after nuclear transfer by microinjection. Here, we apply this method to clone mice from widely available, established embryonic stem (ES) cell lines at late passage. With the ES cell line R1, 29% of reconstructed oocytes developed in vitro to the morula/blastocyst stage, and 8% of these embryos developed to live-born pups when transferred to surrogate mothers. We thus cloned 26 mice from R1 cells. Nuclei from the ES cell line E14 also were shown to direct development to term. We present evidence that the nuclei of ES cells at G(1)- or G(2)/M-phases are efficiently able to support full development. Our findings demonstrate that late-passage ES cells can be used to produce viable cloned mice and provide a link between the technologies of ES cells and animal cloning. It thus may be possible to clone from a single cell a large number of individuals over an extended period.

Animals↗
PubMed1999

Mammalian transgenesis by intracytoplasmic sperm injection.

Coinjection of unfertilized mouse oocytes with sperm heads and exogenous DNA encoding either a green fluorescent protein (GFP) or beta-galactosidase reporter produced 64 to 94 percent transgene-expressing embryos, reflecting DNA-sperm head association before coinjection. Nonselective transfer to surrogate mothers of embryos in the GFP series generated about 20 percent offspring expressing the integrated transgene. These data indicate that exogenous DNA can reproducibly be delivered into an oocyte by microinjected spermatozoa and suggest an adaptable method of transgenesis.

Animals↗
PubMed1999

Dysfunctions of the epididymis as a result of primary carnitine deficiency in juvenile visceral steatosis mice.

The juvenile visceral steatosis mutant mice serve as an animal model of primary carnitine deficiency, classified as the sudden infant death syndrome. The defect in carnitine uptake was recently found to be due to a defect in the carnitine transporter gene. We herein report, for the first time, the characteristics of epididymal dysfunction in juvenile visceral steatosis mice. At 8-9 weeks of age, the epididymis was deformed and weight was significantly increased. Histologically, the duct of the proximal epididymis was dilated due to the accumulation of an unusually high level of spermatozoa. Spermatozoa were extravasated from the epididymal duct into the stroma. In contrast, the duct of the distal epididymis was constricted and contained no spermatozoa. Thus, the epididymal disorder causes obstructive azoospermia, leading to infertility.

Abnormalities, Multiple↗
PubMed1999

Cloning the laboratory mouse.

A brief account is given of early attempts to clone mammals (mice) by transferring cells (nuclei) of preimplantation embryos into enucleated oocytes, zygotes or blastomeres of two-cell embryos. This is followed by a brief review of recent successes using adult somatic cells: mammary gland cells for sheep, muscle cells for cattle and cumulus cells for mice. We have developed a technique for cloning the laboratory mouse by transferring cumulus cell nuclei into enucleated oocytes. With this technique, we have produced a population of over 80 cloned animals, and have carried the process over four generations. Development and fertility of these appear normal. However, the yield is very low; only approximately 1% of injected oocytes are carried to term. The challenge is now to understand the reason for this high loss. Is it a problem of technique, genomic reprogramming, somatic mutation, imprinting or incompatible cell cycle phases?

Animals↗