Biomedical subjects

C Katagiri

Publications and source records attributed to C Katagiri.

At least 55 records · Page 3Linked to original sources

PubMed1994

[A possible role of ultrasound-guided follicular aspiration in induction of ovulation in patients with polycystic ovaries].

To investigate a possible role of ultrasound-guided follicular aspiration in the induction of ovulation in patients with polycystic ovaries (PCO). Serum concentrations of immunoreactive LH (I-LH), bioactive LH (B-LH), FSH, androstenedione, testosterone (T), dehydroepiandrosterone sulfate, E1, E2, and progesterone before and after the follicular aspiration were examined. Follicular aspiration was carried out 7 days after hCG administration in twelve patients refractory to ovulation induction with clomiphene-hMG-hCG. Concentrations (mean +/- SEM) of I-LH, B-LH, and T on day 3 of the menstrual cycle after the aspiration were significantly lower than those before the aspiration (4.8 +/- 0.5 vs 12.6 +/- 1.0 mIU/mL, 18.1 +/- 2.1 vs 50.0 +/- 4.1 mIU/mL, 45.4 +/- 5.0 vs 60.8 +/- 7.1 ng/dl, respectively; p < 0.01). The pattern of LH secretion in response to GnRH challenge test was also normalized after the aspiration. A significant decline in serum levels of E2 and T (p < 0.001) was observed 2h after the aspiration. The ovulation rate was 83.3% (10/12), and one patient achieved pregnancy after the aspiration. The present study suggests that an acute decline in serum levels of ovarian steroids after the aspiration possibly acted on the hypothalamo-pituitary axis of the patients to normalize sensitivity, and the treatment could release the patients from an endocrinologically-mediated vicious cycle and result in the achievement of ovulation.

Adult↗

PubMed1993

Chromosome condensation in Xenopus mitotic extracts without histone H1.

The contribution of histone H1 to mitotic chromosome condensation was examined with the use of a cell-free extract from Xenopus eggs, which transforms condensed sperm nuclei into metaphase chromosomes. When H1 was removed from the extract, the resultant metaphase chromosomes were indistinguishable from those formed in complete extract. Nucleosomal spacing was the same for both. Thus, H1 is not required for the structural reorganization that leads to condensed metaphase chromosomes in this egg extract.

Animals↗

PubMed1993

Cold adaptations in Drosophila. Qualitative changes of triacylglycerols with relation to overwintering.

Triacylglycerols are the major fuel for basal metabolism during the winter in temperate species of the Drosophila melanogaster species group. Differential scanning calorimetry analysis revealed that the transition temperatures of triacylglycerols were lower in diapausing adults than in reproducing ones, and also lower in species or strains adapted to cooler climates than those adapted to warmer climates. These phenomena were correlated to the fatty acid compositions of the triacylglycerols; the proportion of unsaturated fatty acids in the triacylglycerols was higher in the diapausing individuals, and in the species or strains adapted to cooler climates. Furthermore, in the temperate species of the montium species subgroup (D. subauraria, D. biauraria, D. triauraria, and D. rufa), the amount of saturated triacylglycerols was smaller than the value expected on the assumption that fatty acids are randomly distributed in the triacylglycerols, suggesting the nonrandom distribution of unsaturated fatty acids among triacylglycerols. This may facilitate the lowering of the transition temperature of triacylglycerols, and hence may be related to the ability of Drosophila to cope with temperate climates.

Adaptation, Physiological↗

PubMed1993

Immuno-electron microscopic localization of calmodulin and calmodulin-binding proteins in the mouse germ cells during spermatogenesis and maturation.

When extracts of mouse testis were Western-blotted against a monoclonal antibody which reacts with calmodulin in the presence of Ca2+, all calmodulin was associated with the macromolecules of molecular weight above 50 kDa. Immuno-electron microscopy of testes using this antibody indicated that calmodulin is localized at higher density in the nucleus and cytoplasm of germ cells during the developmental phase between pachytene and round spermatid, showing the highest level just before meiotic divisions. There was no special association of calmodulin to any organelles in these cells. Extremely low levels of calmodulin occurred in spermatogonia and other testicular tissue cells. Calmodulin decreased dramatically as spermatids underwent metamorphosis, becoming detectable only at the perinuclear space of sperm heads. Further relocation to the postacrosomal region occurred during sperm transit to the cauda epididymis. Immunodetection after the calmodulin overlay on ultrathin sections revealed a sharp increase of calmodulin immunogold deposits in the nuclei of spermatids accompanying their condensation. The results indicate that some calmodulin-binding proteins, but not calmodulin itself, accumulate in the nuclei during the final steps of spermiogenesis.

Animals↗

PubMed1993

Increases in protein phosphatase 2B activity in lymphoid tissues and T-lymphocytes of autoimmune MRL/MpJ-lpr/lpr mice.

The assay conditions for protein phosphatase 2B (PP2B) in crude extracts from mouse lymphoid tissues and lymphocytes were extensively investigated. Under the conditions elucidated, the PP2B activity was measured in autoimmune-prone MRL/MpJ-lpr/lpr mice (MRL/lpr mice) and two control strains, MRL/MpJ- +/+ mice (MRL/+/+ mice) and C3H/HeJ mice. In the control mice, PP2B activity was distinctly higher in spleen and thymus than brain and liver. PP2B activity was further elevated in spleen of MRL/lpr mice than in the controls. Furthermore, we observed a specific increase in PP2B activity in T lymphocytes from MRL/lpr mice as compared with in those from control mice. On the other hand, no alteration was observed in PP2B activity in B lymphocytes. These results suggest the involvement of PP2B in the abnormal signal transduction and proliferation of T lymphocytes in MRL/lpr mice.

Animals↗

PubMed1992

Treatment of low density lipophorin with lipoprotein lipase: diacylglycerol content has no effect on dissociation of apolipophorin III from low-density lipophorin.

The mechanism of the conversion of low-density lipophorin (LDLp) to high-density lipophorin (HDLp) in long-distance flight insects was investigated using a lipoprotein lipase from a bacterium, Alcaligenes sp. Diacylglycerol of LDLp was steadily hydrolyzed in vitro by the lipase, resulting in a 90% loss of diacylglycerol from LDLp during incubation. The "lipase-treated LDLp" thus obtained still contained associated apolipophorin-III (apoLp-III). These data suggest that the dissociation of apoLp-III is independent of the depletion of diacylglycerol from LDLp, and that the decrease in particle diameter caused by the depletion of diacylglycerol does not force the dissociation of apoLp-III from the lipophorin particle. Some physico-chemical properties of the lipase-treated LDLp were measured.

Alcaligenes↗

PubMed1991

Structure of Colorado potato beetle lipophorin: differential scanning calorimetric and small-angle X-ray scattering studies.

The structure of lipophorin, isolated from hemolymph of the Colorado potato beetle, was investigated by differential scanning calorimetry (DSC) and small-angle X-ray scattering. The DSC heating curves of intact lipophorin showed endothermic peaks that were similar to peaks obtained with the hydrocarbon fraction isolated from this lipophorin. The observed peaks correlated with the transition of the hydrocarbons from an ordered into a more disordered state. Changes in structure of the lipophorin particles with increasing temperature were also observed by small-angle X-ray scattering studies. The structural organization of lipophorin was further elucidated by simulation analysis, using a three-layered symmetrical sphere as a model. These studies revealed that lipophorin from the Colorado potato beetle is a sphere with a maximum diameter of 175 A. The sphere is composed of three radially symmetrical layers of different electron densities. The outer layer (37.5-39.5 A in thickness) is composed of phospholipid, apolipophorin I, and part of apolipophorin II. The middle layer (5-10 A) contains diacylglycerol, the rest of apolipophorin II, and probably beta-carotene. The core of the particle (40-45 A) only contains hydrocarbons. This structure differs from another model, previously proposed for cockroach and locust lipophorins [Katagiri, C., Sato, M., & Tanaka N. (1987) J. Biol. Chem. 262, 15857-15861], in the small size of the middle layer. The volume of the middle layer correlated well with the low diacylglycerol content of this lipophorin.

Animals↗

PubMed1991

Primary structure of toad sperm protamines and nucleotide sequence of their cDNAs.

Acid extract of mature sperm of the toad, Bufo japonicus, exclusively comprised sperm-specific basic proteins which moved faster than somatic histones on acid/urea/Triton X-100 polyacrylamide gel electrophoresis. When these proteins were purified by reversed-phase high-performance liquid chromatography they were found to consist of three components; one of these was a phosphorylated form of another, so that there were only two distinct components (P1 and P2). Amino acid sequence analyses indicated that the components both contained 39 amino acid residues, with 43.6% Arg, and differed only in the 28th amino acid residue (P1, Asp; P2, Glu). They had molecular masses of 5092 Da (P1) and 5106 Da (P2). The nucleotide sequences of cDNA clones encoding P1 (245 bases) and P2 (305 bases) showed that the difference in the amino acid residue between P1 and P2 was due to the difference of a nucleotide at position +87. Both cDNAs possessed a canonical signal (AATAAA) for polyadenylation and/or cleavage of transcript at the 3' untranslational region. Statistical analyses of amino acid sequence similarities suggested that the Bufo protamines are homologous with the protamines of fishes rather than with those of avian/mammalians.

Amino Acid Sequence↗

PubMed1991

Egg exudate-induced reduction of sperm lysin sensitivity in the vitelline coat after fertilization of Bufo japonicus and its participation in polyspermy block.

The jellyless eggs of Bufo japonicus or those from which the vitelline coats (VCs) had been removed (denuded eggs) were electrically activated. The exudate that accompanied egg activation (AEX) was collected to study its role in preventing polyspermy. When dejellied (but VC intact) eggs were treated with AEX, the eggs lost not only fertilizability but also the sensitivity of their VCs to the sperm lysin. By contrast, denuded eggs treated with AEX were fertilizable; even activated eggs were highly fertilizable, provided they were deprived of their VCs and inseminated 30 min after activation. The loss of sensitivity to sperm lysin occurred in VCs 3-5 min after activation either in De Boer's or 1/20 De Boer's solution. The activity of AEX to reduce the sensitivity of VCs to sperm lysin was heat-sensitive and dependent on Ca2+, but it was not affected at all by the variety of protease inhibitors used. The activity was lost by the preincubation of AEX with fragmented VCs in the presence of Ca2+, suggesting Ca(2+)-dependent binding of AEX molecules to the VC at fertilization. Immunocytochemical studies employing anti-AEX rabbit serum showed that the pertinent antigens were localized in the cortical granules of unfertilized eggs and in both the inner surface of VCs and the perivitelline space of fertilized eggs. We conclude that the AEX-induced loss of lysin sensitivity in VCs and the deposition of cortical granule materials on the inner wall of VCs constitute a slow and permanent block to polyspermy.

Animals↗

PubMed1991

Characterization of the ooplasmic factor inducing decondensation of and protamine removal from toad sperm nuclei: involvement of nucleoplasmin.

Immunohistochemical studies with antiserum against the protamines of the toad, Bufo japonicus, revealed that the sperm nucleus loses protamines within 5 min after entry into the egg. Likewise, lysolecithin-permeabilized sperm incubated with the egg extract lose the protamines within 1 min, accompanied by nuclear decondensation. The activities that induce both protamine removal and decondensation in sperm nuclei were found in extracts from growing and mature oocytes and pregastrula embryos, but not in postneurula embryos or adult tissues. SDS-PAGE analyses revealed that the egg extract removed not only protamines from the Bufo sperm, but also selectively the sperm-specific basic proteins from sperm nuclei of Xenopus laevis. The protamine-removing activity (PRA) was partially purified from egg extracts as negatively charged macromolecules by anion-exchange chromatography and gel filtration. The PRA was heat-stable (100 degrees C, 10 min) and sensitive to proteinase K, but not to RNase A and DNase I. Immunoblot analysis of the supernatant after incubation of Bufo sperm in the fraction with the PRA revealed that protamines derived from sperm nuclei were associated with a major protein of the fraction. This protein exhibited mobilities of 140 and 36 kDa on native- and SDS-PAGE, respectively, with the isoelectric points in the range 4.2 to 4.5 and possessed an amino acid composition quite similar to that reported for Xenopus nucleoplasmin. We propose that in fertilized eggs the protamines are removed from sperm nuclei by nucleoplasmin by binding to but not by enzymatic degradation of the protamine.

Amino Acids↗

PubMed1991

Isolation of cDNA for a Xenopus sperm-specific basic nuclear protein (SP4) and evidence for expression of SP4 mRNA in primary spermatocytes.

A cDNA library was prepared in lambda gt 11 from poly(A)+ mRNA isolated from a pure population of Xenopus round spermatids and screened with an antibody against SP3-5 (sperm-specific proteins) of Xenopus sperm. Positive clones were sequenced and an arginine-rich clone, designated pXSP531, was obtained. The 473-nucleotide sequence of pXSP531 contained an open reading frame of 237 nucleotides which was preceded by a 5' untranslated region of 67 nucleotides. The 3' untranslated region contained 149 nucleotides, including a consensus polyadenylation signal (AAATAAAA). Twenty nucleotides of a poly(A) tail was contained in the pXSP531. SP3-5 were separated from each other by reverse-phase chromatography and sequenced. The amino acid sequence of the peptide fragments which were obtained by digestion of SP4 with V8 protease and separated by reverse-phase chromatography was identical to the sequence of the N-terminal 43 and C-terminal 15 amino acids deduced from the nucleotide sequence of pXSP531. This result demonstrates that pXSP531 encodes SP4. Northern hybridization of RNA extracted from primary spermatocytes and round spermatids on Days 0 and 6 with SP4 cDNA probe (pXSP531) showed that SP4 mRNA is present both in primary spermatocytes and in round spermatids as is protamine mRNA in the rainbow trout. The size of the SP4 mRNA in round spermatids on Day 0 was longer by 60 nucleotides compared to that in primary spermatocytes and that in spermatids on Day 6 was shorter by 30 nucleotides compared to that on Day 0. These size differences were due to differences in the length of the poly(A) tracts because digestion of poly(A) with ribonuclease H resulted in the shortening of mRNA to the same size for three stages.

Amino Acid Sequence↗

PubMed1991

Occurrence of H1 subtypes specific to pronuclei and cleavage-stage cell nuclei of anuran amphibians.

Male pronuclei were induced in vitro by incubating the lysolecithin-permeabilized sperm nuclei of anuran amphibians Bufo japonicus and Xenopus laevis with the extracts from homologous eggs, and nuclear basic proteins were analyzed by two-dimensional gel electrophoresis. By 5 min after the incubation, the sperm nuclei had completely lost sperm-specific proteins but possessed a whole set of nucleosomal core histones, except that H2A was mostly replaced by a putative H2A.X. The pronuclei did not possess any H1 histone subtypes found in differentiated somatic cell nuclei, but instead possessed components showing electrophoretic mobilities distinct from other H1 histones. This protein, designated as H1X, was regarded as an H1 subtype on the basis of its solubility in acids or salt and its lysine-rich amino acid composition. Peptide mapping using V8 protease further indicated that H1X is not a post-transcriptionally modified form of other somatic type H1 histones. By the time of chromosome condensation, pronuclear histones comprised H1X, H2A.X, H2B, H3, and H4. During embryonic development, H1X persisted in the nuclei up to the blastula stage, but mostly disappeared at the gastrula stage concomitant with the appearance of H1 subtypes of differentiated cells and the replacement of H2A.X by H2A. We conclude that H1X represents a maternally stored histone variant specific to nuclei of cleaving embryos.

Amino Acids↗

PubMed1990

Occurrence of nonlymphoid leukocytes that are not derived from blood islands in Xenopus laevis larvae.

Previous immunohistochemical observations using the monoclonal antibody (XL-1) which recognizes all types of leukocytes in Xenopus laevis revealed the occurrence of XL-1+ cells in the mesenchyme throughout the early larval body, before the appearance of any lymphocytes. The present experiments were performed to determine whether these leukocytes originate, like lymphocytes and red blood cells (RBCs), in the ventral blood islands (VBI) or the dorsolateral plate (DLP). For tracing the derivation of cells, a specific staining by quinacrine to nuclei of X. laevis and Xenopus borealis hybrid (LB) cells was used to distinguish them from X. laevis (LL) cells. Orthotopic graftings of VBI tissue from st.22-23 LB embryos to the stage-matched LL embryos and examinations at st.44-45 before differentiation of the lymphocytes showed that the proportion of XL-1+ LB cells was always significantly lower than that of RBCs with the same marker in all experimental larvae. The head (LB)-body (LL) chimeras from st.22-23 embryos and culture of the head-portions as VBI- and DLP-free explants from st.14-23 embryos both demonstrated that a significant number of XL-1+ cells which had originated in the head portions had begun to differentiate by st.42-43. These results indicate that there is a significant population of larval nonlymphoid leukocytes (mostly macrophages) that do not originate from either the VBI or DLP region, and are distributed in the mesenchyme throughout the body.

Animals↗

PubMed1989

Ontogeny and tissue distribution of leukocyte-common antigen bearing cells during early development of Xenopus laevis.

To analyze the ontogenic emergence of leukocytes during early development, a mouse monoclonal antibody (IgG1), designated as XL-1, was produced against the peritoneal macrophages of adult Xenopus laevis. The XL-1 determinant was expressed on all types of leukocytes, including lymphocytes, granulocytes, thrombocytes and macrophages, but not on erythrocytes of either larvae or adults. Immunohistochemical observations of the hemopoietic organs revealed that the XL-1+ cells with granulocyte and/or macrophage morphology appeared at st.36-37 in the liver, at st.44-45 in the mesonephric and the thymus rudiments, and at st.47 in the spleen. The XL-1 determinant was expressed on the precursor cells of T lymphocytes in the thymus rudiments at st.46-47, on the pre-B cells in the liver rudiments at st.47, and on lymphocytes in the spleen at st.48-49. A few XL-1+ cells were present in the ventral blood island of the st.35/36 embryos, where differentiating erythrocytes had predominated since st.28. XL-1+ cells with a macrophage-like morphology were found in several locations of the mesenchyme in the st.32 embryos, before the establishment of vascularization at st.33/34 and far earlier than the emergence of lymphocytes.

Animals↗

PubMed1988

Bufo japonicus japonicus and Xenopus laevis laevis egg jellies contain structurally related antigens and cortical granule lectin ligands.

The antigenic relationship of the egg jelly coat glycoproteins from Bufo japonicus japonicus and Xenopus laevis laevis was investigated using agar double diffusion methods. The presence of ligands in the jelly coats for the cortical granule lectin from X.l. laevis eggs was also investigated. Anti-jelly serum for both anuran species crossreacted with the jelly coat from the other species with precipitin patterns of identity. Each egg jelly coat of both species contained two ligands for the cortical granule lectin. Although the ligands in the two different jelly coats appeared to react with the lectin in a pattern of identity, the species ligands were antigenically distinguishable using anti-Xenopus jelly serum. The observations that the two anuran egg jelly coats were antigenically related and that they both contained ligands for the X.l. laevis cortical granule lectin was interpreted in terms of fertilization mechanisms in the two different species. In addition, these observations bring into question the currently accepted phylogenetic relationship of B.j. japonicus and X.l. laevis.

Animals↗

PubMed1988

Human sperm nuclei can transform into condensed chromosomes in Xenopus egg extracts.

The conditions necessary for inducing pronucleus formation and chromosome condensation of human sperm nuclei were studied using Xenopus egg extracts. When lysolecithin (LC)-and dithiothreitol (DTT)-treated spermatozoa were incubated with egg extract prepared with an extraction medium containing 10 mM EGTA, sperm nuclei transformed into chromosomes, bypassing the pronuclear stage. On the contrary, LC-DTT-treated spermatozoa incubated in egg extract without EGTA mimicked LC-permeabilized Xenopus spermatozoa in that they underwent pronucleus formation accompanied by DNA synthesis and subsequent chromosome condensation in the correct chronological order. These observations suggest the importance of intracellular calcium for regulating the states of nuclear chromatin. LC-permeabilized human spermatozoa were not responsive to the egg extract without any additives, but formed pronuclei when incubated with the egg extract supplemented with 5-10 mM DTT. However, subsequent chromosome condensation of sperm nucleus did not occur in the DTT extract. This suggests that disulfide-reducing agent blocks transformation of sperm pronuclei into condensed chromosomes.

Animals↗

PubMed1988

Classification, inhibition, and specificity studies of the vitelline coat lysin from toad sperm.

The sonicated supernatant of the sperm of the toad, Bufo japonicus, can digest easily the vitelline coat (VC) of uterine eggs, and to a lesser extent the VC of coelomic eggs, but not that of activated eggs. The VC lysis and fertilization were competitively inhibited in the presence of t-butyloxycarbonyl-L-Gln-L-Arg-L-Arg-4-methylcoumaryl-7-amide (Boc-Gln-Arg-Arg-MCA), suggesting the involvement of proteases in the fertilization process. Starting from a sonicated supernatant, a potent VC lysin, possessing hydrolytic activity on Boc-Gln-Arg-Arg-MCA, was obtained by anion-exchange chromatography and gel filtration. The activity of the partially purified lysin was inhibited by diisopropyl fluorophosphate (DFP) and by such trypsin inhibitors as soybean trypsin inhibitor, leupeptin, and (p-amidinophenyl) methanesulfonyl fluoride hydrochloride, but not by chymostatin, E-64, and ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid. The molecular weight of the lysin was estimated to be 32K, based on the fluorographic image of 3H-DFP binding to the lysin on sodium dodecyl sulfate gel electrophoresis. The VC lysin was most active at pH 7.0-7.6 and under low ionic strength equivalent to fresh water. The release of the VC lysin was induced upon incubation of sperm with the contents of oviducal pars recta granules (PRG), which are known to induce the acrosome reaction. We conclude that the protease studied here represents the VC lysin of toad sperm that is involved in fertilization by digesting the VC of uterine eggs, probably released as a result of the acrosome reaction induced by PRG.

Animals↗

PubMed1988

Egg envelope conversion following fertilization in Bufo japonicus.

The envelope of the Bufo japonicus egg becomes impenetrable to sperm following fertilization. Electrophoretic analysis of envelopes showed that two glycoprotein components with apparent molecular weights of 65,000 and 61,000 were hydrolyzed during fertilization to 62,000 and 58,000, respectively. These two envelope components were structurally related as shown by peptide mapping and deglycosylation studies. Hardening of the envelope following egg activation was also observed, as detected by an increase in the envelope melting temperature. The involvement of proteolytic activities in the envelope hydrolysis and hardening reactions was demonstrated using protease inhibitors, and was verified for the hydrolysis reaction by observing a loss of mass in deglycosylated envelope components obtained before and after fertilization. A low ionic strength medium (less than 50 mM) was required for both the hardening and hydrolysis reactions. Envelopes from eggs activated in a high ionic strength medium were resistant to lysin from sperm, indicating that neither hydrolysis nor hardening was necessary to block lysin activity on the envelope. Both envelope hydrolysis and hardening could be effected in the absence of sperm (i.e., when eggs were activated by electric shock) and after egg jelly had been removed, indicating that neither sperm nor jelly factors were required for the envelope modifications. In addition, when eggs were activated in the presence of NH4Cl to suppress cortical granule exocytosis, envelope hardening and hydrolysis were still observed, indicating that a cortical granule-derived factor may not be involved.

Animals↗