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Biomedical subjects

Y Tsunoda

Publications and source records attributed to Y Tsunoda.

At least 163 records · Page 9Linked to original sources
PubMed1987

Electrofusion for the pronuclear transplantation of mouse eggs.

The present study was undertaken to determine the efficiency of HVJ treatment and electrofusion for pronuclear transplantation in the mouse. The output voltage and duration of the pulses were fixed to 200 microsec at 10 V or to 150 microsec at 15 V for electrofusion, because the maximum rates of blastomere fusion of 2-cell embryos and development of fused embryos in vitro were obtained under these conditions. Although the proportion of eggs with fused karyoplast (78%) and the fused eggs developed to morulae or blastocysts the proportion of pregnant recipients and young obtained after treatment of fused eggs was not significantly different between these two procedures. It is advised that electrofusion can be used as a fusogenic procedure for pronuclear transplantation in the mouse in some cases where HVJ cannot be applied.

Animals↗
PubMed1987

Beneficial effect of agar for the frozen storage of bisected embryos.

The effect of agar embedding on the viability of intact and bisected goat embryos during freezing and thawing was examined. Blastocysts or hatched blatocysts were bisected into haves by micromanipulation. After embedding with or without agar, they were stored by deep freezing. After thawing, undamaged and some partially damaged embryos were transferred into uteri of recipients. Of 22 demi-embryos embedded with agar, only one was undamaged, but of 58 demi-embryos embedded with agar, 29 were undamaged. Although one set of monozygotic twins was obtained after the transfer of 15 sets of frozen-thawed bisected embryos, the pregnancy rate (47%) and the proportion of young (27%) were lower than those obtained by transfer of frozen-thawed, intact embryos (67 to 80% for pregnancy rate, 45 to 53% for the young).

Journal Article↗
PubMed1987

Development of one or two blastomeres from eight-cell mouse embryos to term in the presence of parthenogenetic eggs.

This study was undertaken to develop a new technique to produce identical offspring by aggregating a quarter or eighth embryo with a parthenogenetically activated egg in the mouse. One or two blastomeres from 8-cell embryos were aggregated with a parthenogenetic 4-cell egg from which one or two blastomeres had been removed. After micromanipulation and culture for 2 d in vitro, the morphologically normal blastocysts were transferred to the uterus of recipient females. The success rate in micromanipulation of eggs was 93 to 100%: aggregation of blastomeres occured about 60% of the time and the proportion of live young after transfer of aggregated eggs was 11 to 33% for the quarter and 2 to 24% for the eighth egg. The proportion of chimaeras as judged by coat color was 10% for the quarter and 20% for the eighth egg. However, GPI-1 analysis and progeny testing could not detect a parthenogenetic contribution in all offspring. The mean number of young obtained from one embryo was 1.7 for the quarter and 1.6 for the eighth embryo. The maximal number of young obtained from splitting one 8-cell embryo into quarters was three and into eighths was four. The mice of each set derived from a single embryo were of the same sex. Our study clearly demonstrates that the parthenogenone can assist development of the quarter and eighth mouse embryo to term. The proportion of chimaeras is low compared with that obtained when two fertilied eggs are combined.

Journal Article↗
PubMed1987

Ca2+ currents and acid secretion in the isolated parietal cell involved in response to gastrin, compound 48/80, and ethylenediamine tetraacetic acid.

In intact guinea pig parietal cells, gastrin or compound 48/80 caused an initial increase in cytosolic Ca2+ concentration and subsequent acid secretion, owing to release of intracellulary stored Ca2+ besides the Ca2+ entry from the extracellular space. However, the maximum gastrin-induced Ca2+ entry into the cell was delayed by 60 min, a time which coincided with sustained acid secretion (by gastrin) that was dependent on medium Ca2+. On the other hand, there are two ATP-dependent Ca2+-removal systems detected in either plasmalemma or smooth surfaced membrane besides that of mitochondria. The plasmalemmal Ca2+-removal system was dependent on calmodulin. Smooth surfaced membrane vesicles caused an ATP-dependent Ca2+ uptake that was almost similar to that taken by saponin-permiabilized cell. In this system (permeable cell), myo-inositol 1,4,5-triphosphate (InsP3) caused the release of ATP-accumulated Ca2+ into the cytosol, suggesting an ATP-dependent and InsP3-sensitive Ca2+ pool(s) is in or near the smooth surfaced membranes. The ATP-dependent Ca2+ uptake by vesicles was markedly enhanced by the stimulation of cells with gastrin, compound 48/80, or EDTA. The increase of this Ca2+ uptake in stimulated cells by plasmalemmal vesicles exceeded that by smooth surfaced ones. The increase of the Ca2+ uptake by plasmalemmal vesicles was abolished by the cease of intracellular Ca2+ release without Ca2+ entry. In addition, gastrin or compound 48/80 evoked an early Ca2+ efflux across the plasma membrane owing to a pump that was independent of medium Ca2+ in intact cells. These results suggest that in the first acid secretion by gastrin or others, the Ca2+ released, which may be derived from an ATP-dependent and InsP3-sensitive Ca2+ pool, is mainly pumped out by the plasmalemmal Ca2+-removal system rather than the intracellular Ca2+-removal system; whereas the sustained acid secretion by gastrin required medium Ca2+ and in this phase, Ca2+ efflux across the plasma membrane became lower, suggesting that an ATP-dependent Ca2+ pool may be replenished by Ca2+ entering from the extracellular space.

Aminopyrine↗
PubMed1987

[The effect of splenectomy in immature mice].

Overwhelming postsplenectomy infection in childhood has been investigated extensively, both clinically and experimentally. The immunological change after splenectomy in immature mice is reported in this paper. The studies were carried out in 3-week-old immature mice and in 10-week-old mature mice groups. The immunological change after splenectomy in immature mice were as follows. One week after splenectomy, cellular immunity decreased, so that the phagocytosis of macrophages and the function of granulocytes were decreased. Three weeks after splenectomy, cellular immunity and the function of granulocytes improved but the phagocytosis of macrophages was still at the low level. Cellular immunity, the function of granulocytes and the phagocytosis of macrophages were within normal range 5 weeks after splenectomy. Several previous reports have demonstrated a lower IgM concentration. Tuftsin deficiency and activity decreased in opsonization after splenectomy. We showed the more primitive responses than cellular immunity are also depressed in this paper, that is, splenectomy in immature mice resulted in decrease in the phagocytosis of macrophages and dysfunction of granulocytes.

Animals↗
PubMed1986

An ATP-dependent and inositol trisphosphate-sensitive Ca2+ pool linked with microfilaments of the parietal cell.

In digitonin-permeabilized parietal cells, myo-inositol 1,4,5-trisphosphate (Ins P3) or Ca2+ ionophore (A23187) increased the cytosolic Ca2+ concentration due to the intracellular Ca2+ release. Addition of ATP decreased the cytosolic Ca2+ concentration due to the rapid Ca2+ re-uptake into the same or similar pool which releases Ca2+ from a non-mitochondrial location (measured by quin2/AM and 45Ca2+). Cytochalasin B failed to increase the cytosolic Ca2+ concentration in response to Ins P3 or A23187 and even failed to decrease the cytosolic Ca2+ concentration in response to ATP. This implies that the ATP-dependent and Ins P3-sensitive Ca2+ pool is linked with the microfilaments of the parietal cell. In intact parietal cells, A23187 increased the amino[14C]pyrine accumulation (an index of acid secretion), that was independent of medium Ca2+. This increase of acid secretion was inhibited by the pretreatment with cytochalasin B. This suggests that medium Ca2+-independent acid secretion (by A23187) is regulated by the microfilaments. Therefore, there is a close relationship between the intracellular Ca2+ metabolism, microfilaments and acid secretion.

Actin Cytoskeleton↗
PubMed1986

Gastrin induces intracellular Ca2+ release and acid secretion regulation by the microtubular-microfilamentous system.

In the absence of extracellular Ca2+ gastrin induced accumulation of amino [14C]pyrine as an index of acid secretion and evoked a cytosolic Ca2+ rise (measured by quin2/AM), suggesting that an intracellular Ca2+ release after the activation of the gastrinergic pathway may trigger acid secretion. In isolated parietal cells pretreatment with colchicine or cytochalasin B abolished the amino [14C]pyrine accumulation and the rise in cytosolic Ca2+ concentration evoked by gastrin. The results suggest that the microtubular-microfilamentous system regulates gastrin-induced intracellular Ca2+ release and acid secretion.

Aminopyrine↗
PubMed1986

Effect of cutting the zona pellucida on the pronuclear transplantation in the mouse.

A new and reliable pronuclear transplantation procedure for the mouse egg has been developed by McGrath and Solter ('83). To overcome the technical difficulties of such a procedure, especially in uniformly preparing enucleation pipettes and in reducing damages during micromanipulation, we have examined the effect of cutting the zona pellucida of the eggs. By making a slit in the zona of an egg, the time for pipetting and exchange of pronuclei between eggs was shortened because the sharp tip of the pipette was not necessary. Although the proportion of pregnant recipients and young obtained after transfer of pronuclear transplanted eggs cultured for 1 day or 3 days was quite low, it was significantly increased (70% for pregnancy rate and 32% for the young) following transfer of eggs cultured for 4 days. These values were comparable with those after transfer of unoperated eggs cultured to morulae and blastocysts.

Animals↗
PubMed1985

Participation of the microtubular-microfilamentous system on intracellular Ca2+ transport and acid secretion in dispersed parietal cells.

Biphasic responses of amino[14C]pyrine accumulation and oxygen consumption were registered by gastrin stimulation in dispersed parietal cells from guinea pig gastric mucosa, and this was mimicked with the calcium ionophore A23187. The characteristics of these phases (first phase and second phase) were distinguished by the differences in the requirements of extracellular Ca2+. The first phase evoked by gastrin or ionophore A23187 was independent of extracellular Ca2+, whereas the second phase was not. In the first phase, fluorescence of a cytosolic Ca2+ indicator (quin2-AM) increased with the stimulation of ionophore A23187 and carbamylcholine chloride in the presence of extracellular Ca2+. In addition, an increase in cytosolic Ca2+ induced by ionophore A23187, but not by carbamylcholine chloride was also observed in the absence of extracellular Ca2+, suggesting that Ca2+ pool(s) in parietal cells might be present in the intracellular organelle. Cytochalasin B and colchicine, but not oligomycin, could eliminate this cytosolic Ca2+ increase induced by A23187 in a Ca2+-free medium. On the other hand, in a Ca2+-free medium, addition of ATP after pretreatment with digitonin could diminish the cytosolic Ca2+ increase brought about by A23187. This was also observed with oligomycin-treated cells, but not with cytochalasin B-treated cells. Similarly, subcellular fractionation of a parietal cell which had been pretreated with cytochalasin B or colchicine in an intact cell system reduced the rate of ATP-dependent Ca2+ uptake. These observations indicate that intracellular Ca2+ transport in dispersed parietal cells may be regulated by the microtubular-microfilamentous system. In conclusion, this study demonstrates the possibility of the existence of intracellular Ca2+ transport mediated by gastrin or ionophore A23187 and regulated by the microtubular-microfilamentous system in parietal cells.

Actin Cytoskeleton↗
PubMed1985

Production of monozygotic twins following the transfer of bisected embryos in the goats.

Embryos at the morula, blastocyst and hatched blastocyst stage were obtained from superovulated and naturally ovulated Japanese native goats. They were bisected into halves with a glass needle, and transferred immediately or after culture (for morula) to recipients. None of five does which received bisected morula became pregnant. Three of nine goats became pregnant after transfer of bisected hatched blastocysts, six of eleven recipients became pregnant. Four of them produced monozygotic twins and the remaining two produced singles. The present study demonstrated that the hatched blastocyst is suitable for bisection in the goat.

Journal Article↗
PubMed1985

Comparison of hemodynamic effects of morphine, butorphanol, buprenorphine and pentazocine on ICU patients.

Morphine and narcotic agonist-antagonists have been used to assist ICU patients in adapting to mechanical ventilation. In this study, 10 mg of morphine and the equipotent doses of synthetic analgesics, 2 mg of butorphanol, 0.6 mg of buprenorphine or 30 mg of pentazocine were administered intravenously to 29 patients requiring a ventilator. Hemodynamic effects on the heart rate, mean arterial pressure (MAP), cardiac index, stroke index, left ventricular stroke work index, mean pulmonary arterial pressure (MPAP), pulmonary capillary wedge pressure (PCWP) and systemic and pulmonary vascular resistance (PVR) were measured. The hemodynamic effects of the four drugs were mild and not statistically significant except for the reduction in PCWP and the increase in PVR after morphine and the increase in MAP and MPAP after pentazocine administration. These doses of the four drugs could be given safely even in critically ill patients. The hemodynamic effects of these analgesics showed a similarity between the administration of butorphanol and morphine, and between buprenorphine and pentazocine. This study demonstrates that morphine and butorphanol are preferred to the cases with hypertension, increased pulmonary arterial pressure or wedge pressure and that pentazocine and buprenorphine are more suitable for the cases with hypotension or hypovolemia.

Adult↗
PubMed1984

Monoclonal antibodies to porcine zona pellucida antigens and their inhibitory effects on fertilization.

Five hybridomas which produce monoclonal antibodies (Mabs) to porcine zona pellucida (ZP) were established. The immunoglobulin classes were IgG2a from hybridoma B11C8 and IgM from the other four. Using immunofluorescent staining, the Mab from B11C8 stained only porcine oocytes, the Mab from G10G5 stained oocytes of pigs and hamsters but Mabs from C6H1, D3H4, G10F9 stained oocytes of pigs, humans, hamsters, rats and mice. Mabs from B11C8 and G10F9 strongly blocked boar sperm binding to porcine ZP but other Mabs produced only slight blocking. However, no Mabs could block sperm penetration during in vitro fertilization (IVF) of hamster oocytes. When a goat antibody (IgG) to mouse serum gamma-globulin was applied after each Mab as a second antibody, only Mab from G10G5 impaired IVF of hamster oocytes.

Animals↗
PubMed1984

Effects of ethyl-2-(4-chlorophenyl)-5-ethoxy-4-oxazole acetate (Y-9738) on the serum lipids of patients with hyperlipidemia and/or hypo-HDL-emia.

With the view of examining the serum lipid metabolism-improving action of a new compound, ethyl-2-(4-chlorophenyl)-5-ethoxy-4-oxazole acetate (Y-9738), 900 mg was administered to 47 patients with various diseases associated with hyperlipidemia and/or hypo-HDL (high density lipoprotein)-emia for successive 16 weeks. Serum HDL-cholesterol increased significantly 4 weeks after the administration (mean 11.8%, p less than 0.01). In the patients with hypo-HDL-emia who showed the initial level of 50 mg/dl or less, the degree of increase was more remarkable (mean 16,4%, p less than 0.01), and a significant increase was noted until 12 weeks later. Further, a similar change was noted in respect to serum HDL-phospholipid. The main apoprotein of HDL, apoprotein A (I + II) began to increase significantly 4 weeks after the institution of the administration. At the end of the trial, it increased by mean 31% (p less than 0.01). Y-9738 did not exert any significant effect on serum total cholesterol, triglyceride and phospholipid, but it caused a reduction in so-called atherogenic indexes.

Adult↗