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Biomedical subjects

I Moriyama

Publications and source records attributed to I Moriyama.

At least 73 records · Page 4Linked to original sources
PubMed1987

The study of placental L-ascorbate (vitamin C) transport mechanism (using microvillous membrane vesicles).

To investigate the placental L-ascorbate (Vitamin C) transport mechanism, the uptake of L-ascorbate into microvillous membrane vesicles prepared from human term placenta was studied using the rapid filtration technique. The uptake of L-ascorbate into microvillous membrane vesicles was osmotically sensitive. This finding indicated that the uptake of L-ascorbate into microvillous membrane vesicles represented transport into the vesicles. The uptake of L-ascorbate into microvillous membrane vesicles was not dependent on sodium electrochemical gradient. The initial rate of uptake was not changed when the intravesicular space was rendered electrically more negative by membrane diffusion potential induced by the use of highly permeant anions. The initial rate of L-ascorbate transport exhibited saturation kinetics with respect to the L-ascorbate concentration; an apparent Km of 1.33 mM and Vmax of 47p mol/mg protein/20 sec was calculated. The uptake of L-ascorbate into microvillous membrane vesicles was competitively inhibited by D-isoascorbate. These results indicated that transport of L-ascorbate across the placental microvillous membrane vesicles was carrier mediated and was passive transport.

Ascorbic Acid↗
PubMed1987

[Relationship of fetal hind limb and fetal liver on amino acid metabolism in pregnant rats].

A tracer technique for injections into rat fetal abdomen in utero was employed to obtain a better knowledge of amino acid metabolism in fetal hind limb and fetal liver. Calculation of tissue fluid distribution via 3H-inulin space made possible an estimation of the fetal hind limb and fetal liver intracellular amino acid concentration based upon the fetal plasma and fetal tissue amino acid concentration. A significant concentration gradient between fetal plasma and fetal hind limb was found for glutamate (37.3) but not for alanine (9.7) or leucine (3.0). The radioactivity of fetal hind limb and fetal liver after the injection of 1 microCi of radioactive 14C-glutamate 14C-alanine or 14C-leucine into fetal abdomen was measured. In fetal hind limb, significant radioactivity was recognized after 14C-alanine administration, but not after 14C-glutamate administration as against the significant concentration gradient. However, in fetal liver, significant radioactivity was recognized after 14C-glutamate administration, but not after 14C-alanine administration. We concluded that in fetus, glutamate was released from the hind limbs and a large amount taken up by fetal liver.

Amino Acids↗
PubMed1987

[D-glucose reabsorption activity of fetal kidney (by using brush border membrane vesicles of proximal tubule)].

By using brush border membrane vesicles prepared from human mid gestational fetal kidney (cortex), the D-glucose transport mechanism and its developmental pattern was studied by the rapid filtration technique. 1. The transport of D-glucose into brush border membrane vesicles prepared from fetal kidney (18 gestational weeks) did not show a great degree of Na+ gradient (extravesicular greater than intravesicular) dependence. 2. The transport of D-glucose into brush border membrane vesicles prepared from fetal kidney (22 gestational weeks) depended on Na+ gradient. This Na+ dependent D-glucose transport showed overshoot and markedly increased when the intravesicular space was rendered electrically more negative with a membrane potential induced by highly permeant anions or by the K+ diffusion membrane potential via valinomycin. These results indicated that the Na+ dependent active D-glucose reabsorption system in the proximal tubules of kidney might be formed between 18 and 22 gestational weeks and the D-glucose reabsorption mechanism of kidney at 22 gestational weeks was Na+ cotransport dependent on membrane potential as in adult ones.

Absorption↗
PubMed1987

[Absorption of L-alanine in small intestine of human fetus (by using brush border membrane vesicles of jejunum)].

By using brush border membrane vesicles prepared from human mid gestational fetal intestine (jejunum), the intestinal L-alanine transport mechanism was studied using a rapid filtration technique. The uptake of L-alanine by the vesicles was osmotically sensitive. This finding indicated that the uptake of L-alanine by the vesicles represented transport into the vesicles. A Na+ electrochemical gradient (extravesicular greater than intravesicular) stimulated the initial rate of L-alanine uptake, and Na+ dependent uptake of L-alanine into vesicles showed a typical overshoot phenomenon. This overshoot and the initial rate of uptake markedly increased when the intravesicular space was rendered electrically more negative by membrane diffusion potentials induced by with highly permeant anions. A similar stimulation of L-alanine uptake was observed, when membrane potential (inside negative) was imposed by K+ diffusion potentials via valinomycin. These results indicated that an Na+ dependent uptake of L-alanine into the brush border membrane vesicles was dependent on the electrical potential difference of the membrane. The initial rate of L-alanine transport exhibited saturation kinetics with respect to the L-alanine concentration; an apparent Km of Km1; 1.6mM, Km2; 14.1mM, and Vmax of Vmax1; 4.0n mol/mg protein/20sec, Vmax2; 8.2n mol/mg protein/20 sec were calculated. From these results mid gestational fetal intestine (jejunum) already has an L-alanine absorption system which is comparable to the adult one's.

Alanine↗
PubMed1987

[The character of human placental glucose and amino acid transport activity (using microvillous membrane vesicles)].

To elucidate the character of human placental D-glucose and L-alanine transport activity, we investigated the uptake of D-glucose and L-alanine into microvillous membrane vesicles prepared from human early and term placenta using the rapid filtration technique. 1. The uptake of D-glucose into microvillous membrane vesicles did not depend on the Na+ gradient (extravesicular greater than intravesicular). The uptake of D-glucose into vesicles was three times as great as that of L-glucose. And phloretin prominently inhibited the uptake of D-glucose into vesicles. So, it was indicated that the transport mechanism of D-glucose across microvillous membrane was facilitated diffusion. 2. The uptake of L-alanine into microvillous membrane vesicles depended on Na+ gradient (extravesicular greater than intravesicular), so that the transport mechanism of L-alanine across microvillous membrane was a secondary active one. The transport of L-alanine into vesicles prepared from term placenta increased prominently compared to that of early placenta. On the other hand, the transport activity of D-glucose into vesicles prepared from term placenta did not differ from that of early placenta.

Alanine↗
PubMed1987

[Study on Na+ and L-alanine cotransport of the human placenta using microvillous membrane vesicles].

Using microvillous membrane vesicles prepared from human normal term placenta, placental cotransport system of Na+ and L-alanine was studied using rapid filtration technique. The uptake of L-alanine into microvillous membrane vesicles was Na+ ion electrochemical gradient (extravesicular greater than intravesicular) dependent and showed typical overshoot phenomenon. Both Na+ dependent L-alanine uptake and Na+ ion uptake into microvillous membrane were membrane potential dependent and were markedly increased when the intravesicular space was rendered electrically more negative by membrane diffusion potentials, induced by the use of highly permeant anions. L-alanine gradient (extravesicular greater than intravesicular) induced a temporary accumulation of Na+ ions. These results indicated that L-alanine and Na+ ions were cotransported across microvillous membrane and this cotransport was dependent on the electrical potential difference in the membrane.

Alanine↗
PubMed1986

Primary infection of Japanese infants with adult T-cell leukaemia-associated retrovirus (ATLV): evidence for viral transmission from mothers to children.

Primary infection with adult T-cell leukemia virus (ATLV) was investigated by follow-up studies on 16 ATLV-seropositive mothers and their breastfed infants in an ATLV-endemic area of Japan. Maternal antibody to ATLV decreased in all the infants, and was detectable in only three of 12 infants tested 6 months after birth. Reappearance of the antibody 9-18 months after birth was observed in only four of the 16 infants. The ATLV-bearing cells in peripheral blood were detected in all 16 mothers after delivery. None of the 16 infants showed ATLV-bearing cells in peripheral or cord blood sampled at birth, or 1, 3 or 6 months after birth. However, virus-bearing cells in the blood became detectable 9-18 months after birth in 13 of the 16 infants. Maternal antibody and virus-bearing cells were never detected in a control group of seven infants of ATLV-seronegative mothers. These findings provide evidence for the high incidence of primary ATLV infection during early infancy among infants born to ATLV-seropositive mothers and suggest maternal viral transmission. Furthermore, samples of breast milk from all 12 seropositive mothers examined contained cell-associated ATLV capable of being transmitted to peripheral leucocytes of neonates. This finding suggests that one of the possible maternal transmission routes of ATLV is via breast milk.

Adult↗
PubMed1986

[Study on placental L-glutamine transport mechanism using microvilli vesicles].

Using microvillous (brush border) membrane vesicles prepared from human term placenta, the uptake of L-glutamine was studied using a rapid filtration technique. The uptake of L-glutamine into the vesicles was osmotically sensitive. A Na+ electrochemical gradient (extravesicular greater than intravesicular) stimulated the initial rate of L-glutamine uptake and the Na+ dependent uptake of L-glutamine into vesicles showed a typical overshoot phenomenon. This overshoot and the initial rate of uptake were markedly increased when the intravesicular space was rendered electrically more negative by membrane diffusion potentials, induced by the use of highly permeant anions. A similar stimulation of L-glutamine uptake was observed when membrane potential (inside negative) was imposed by K+ diffusion potentials via valinomycin. These results indicated that a sodium dependent uptake of L-glutamine into the microvillous membrane vesicles was dependent on the electrical potential difference of membrane. The initial rate of L-glutamine transport exhibited saturation kinetics with respect to L-glutamine concentration; the apparent Km of 0.42 mM and Vmax of 1.54 nmol/mg protein/20 sec were calculated. The uptake of L-glutamine into the vesicles was competitively inhibited by L-alanine.

Amino Acids↗
PubMed1986

[Study on changes in placental L-alanine transport activity during gestation (using microvillous membrane vesicles].

Using microvillous membrane vesicles prepared from human normal early and full term placenta, we investigated the transport mechanism of L-alanine and the change in its transport activity during gestation. We estimated the purity of microvillous membrane vesicles prepared from human placenta from the relative specific activities (microvilli versus homogenate) of the membrane's maker enzymes, alkaline phosphatase (ALP), 5'-nucleotidase, and gamma-glutamyltranspeptidase ( gamma-GTP). In early pregnancy (12-15 weeks gestational age), the relative specific activities (microvilli versus homogenate) were calculated to be: ALP: 15.3, 5'-nucleotidase: 14.0, gamma-GTP: 8.3, and in full term pregnancy (37-40 weeks gestational age) the relative specific activities (microvilli versus homogenate) were calculated to be: ALP: 16.0, 5'-nucleotidase: 14.8, gamma-GTP: 7.5. The uptake of L-alanine into microvillous membrane vesicles was Na+ electrochemical gradient (extravesicular greater than intravesicular) dependent and this Na+ dependent uptake was membrane-potentially sensitive both in early pregnancy and in full term pregnancy. The kinetics parameter of the initial L-alanine uptake into microvillous membrane vesicles were calculated to be: Km: 0.78 +/- 0.20 mM, Vmax: 0.62 +/- 0.21 nmol/mg protein/20 sec in early pregnancy, Km: 0.80 +/- 0.24 mM, Vmax: 3.53 +/- 0.70 nmol/mg protein/20 sec in full term pregnancy. In conclusion, the placental transport mechanisms of L-alanine in both early and full term pregnancy were the same, and the L-alanine transport activity of full term pregnancy was much greater than that of early pregnancy.

Alanine↗
PubMed1986

[A study on the mechanism of bile acid transport in the human placenta (the passive transport system of taurocholate across microvillous membrane)].

The uptake of taurocholate into microvillous membrane vesicles prepared from human normal full term placenta was studied using a rapid filtration technique. The taurocholate uptake into microvillous membrane vesicles was sensitive to extravesicular osmolarity, and preincubation with the taurocholate increased the uptake of taurocholate into the vesicles. These findings indicate that the uptake of taurocholate by microvillous membrane vesicles represents transport into vesicles. The uptake of taurocholate into vesicles was not dependent on sodium electrochemical gradient (extravesicular greater than intravesicular). But, this uptake was markedly increased when the intravesicular space was rendered electrically more positive by the use of lowly permeant anions or K+ diffusion potentials via valinomycin. These findings indicated that taurocholate was transported into microvillous membrane vesicles as anion. Cholic acid inhibited the uptake of taurocholate into vesicles, but taurine didn't inhibit this uptake. The initial rate of taurocholate transport exhibited saturation kinetics with respect to the taurocholate concentration; an apparent Km of 67 microM and Vmax of 0.30n mol/mg protein/20 sec were calculated. These results indicated that placental taurocholate transport was not active but passive (facilitated diffusion), and taurocholate was transported from fetus to mother via placenta because the blood concentration was higher in fetus than mother.

Bile Acids and Salts↗
PubMed1986

[The transport mechanism of antibiotics using microvillous membrane vesicles (placental transport of fosfomycin)].

Using the rapid filtration technique, the uptake of fosfomycin into microvillous membrane vesicles isolated from human term placental trophoblast was investigated. The microvillous membrane vesicles exhibited the uptake of fosfomycin into an osmotically reactive intravesicular space and it was indicated that the uptake of fosfomycin by microvillous membrane vesicles represented transport into membrane vesicles. The uptake of fosfomycin by microvillous membrane vesicles was not dependent on the Na+ electrochemical gradient or membrane potential. The initial uptake of fosfomycin by microvillous membrane vesicles did not exhibit saturation kinetics with respect to fosfomycin concentration, and increased linearly as the fosfomycin concentration increased. These results indicated that fosfomycin was transported across the microvillous membrane by simple diffusion. L-alanine, L-valine, L-lysine, inorganic phosphate or D-glucose did not inhibit the uptake of fosfomycin into microvillous membrane vesicles. On the other hand, fosfomycin did not inhibit the uptake of L-alanine, L-valine, L-lysine inorganic phosphate or D-glucose into microvillous membrane vesicles. These results revealed that fosfomycin did not affect the placental transport activity of other nutrients.

Biological Transport↗
PubMed1985

[Behaviour of uterine muscle calmodulin and contraction during pregnancy and under estrogen, progesterone administration].

The calmodulin levels of human and rat myometrium were measured during pregnancy and under estrogen, progesterone administration, and uterine muscle contraction at the same time was also measured. The calmodulin concentration in the uterine muscle was increased as the stage of pregnancy advanced. This increase also intensified the maximum contractility of the uterine muscle together with the increase of growth during pregnancy. The calmodulin levels were increased by the administration of estrogen and this increase was restricted by progesterone. As a result, the adjustment of the calmodulin level by administration of these steroid hormones was found to be a very interesting mechanism for studying the physiology of uterine muscle contractions.

Animals↗
PubMed1985

[Nephritogenic glycopeptide (nephritogenoside): its existence in the urine of toxemia patients].

Previously we reported that we succeeded in isolating from human full term placenta, glycopeptide which was immunologically the same as nephritogenic glycopeptide (Nephritogenoside) prepared from human renal GBM (glomerular basement membrane). This time to clarify the correlation between the pathology of toxemia and Nephritogenoside, we examined the existence of Nephritogenoside in the urine of toxemia patients. To purify Nephritogenoside from the urine powder of toxemia patients, we use the same procedures (enzyme digestion, Con A affinity column chromatography e.t.c.) as used in purifying Nephritogenoside from human full term placental TrBM (trophoblast basement membrane). In the urine of toxemia patients we clarified the existence of glycopeptide, which had specific affinity with Con A and was immunologically the same as Nephritogenoside. The existence of Nephritogenoside in the urine of toxemia patients further strengthened the possibility of a relationship between Nephritogenoside and the pathology of toxemia.

Electrophoresis↗
PubMed1985

[Study on the mechanism of placental transport of L-lysine (using human placental microvillous (brush border) membrane vesicles)].

The uptake of L-lysine in human placental microvilli vesicles prepared from human term placenta was studied using the rapid filtration technique. The uptake of L-lysine into the vesicles was osmotically sensitive. This finding indicates that the uptake of L-lysine by placental microvilli vesicles represents transport into the membrane vesicles. The uptake of L-lysine into microvilli vesicles is sodium independent. The initial rate of uptake is markedly increased when the intravesicular space is rendered electrically more negative by membrane diffusion potential induced by the use of highly permeant anions or by K+ diffusion potentials via valinomycin. These results indicate that the sodium independent uptake of L-lysine into the microvilli membrane vesicles is dependent on the electrical potential difference of the membranes. A kinetic analysis of the uptake demonstrated that two transport systems for vesicular entry of L-lysine existed with a Km1 of 0.13 mM, Vmax1 of 590 pmol/mg protein/20 sec, Km2 of 0.91 mM, Vmax2 of 2010 pmol/mg protein/20 sec. The uptake of L-lysine in microvilli vesicles was inhibited by dibasic amino acid (L-arginine, L-ornithine, L-glutamine), but not by other classes of amino acid. These results indicate the existence of a dibasic amino acid specific transport system in placental microvilli membrane.

Arginine↗
PubMed1985

[Studies on L-glutamate transport mechanism in human placental trophoblast microvilli membrane vesicles].

The uptake of L-glutamate in brush border (microvilli) vesicles prepared from human term placenta was studied using the rapid filtration technique. The uptake of L-glutamate into the vesicles occurred osmotically, and preincubation with L-glutamate increased the uptake of amino acid. These findings indicate that the uptake of L-glutamate by placental trophoblast brush border membranes represents the transport into membrane vesicles. A Na+ electrochemical gradient (extravesicular greater than intravesicular) stimulated the initial rate of L-glutamate uptake about three times. The initial rate of transport exhibited saturation kinetics with respect to the L-glutamate concentration; an apparent Km of 0.15 mM and V max of 70 pmol/mg protein in 20 seconds were calculated. The uptake of L-glutamate into the vesicles was competitively inhibited by L-glutamate and L-cysteate (acidic amino acid). These results indicate that a Na-dependent acidic amino acid specific transport system exists in the placental trophoblast microvilli membrane. These results indicate that the transport of L-glutamate across the placental microvilli membrane is sodium-dependent and carrier mediated.

Aspartic Acid↗
PubMed1985

[Tissue polypeptide antigen in gynecological cancer].

Serum tissue polypeptide antigen (TPA), CEA and IAP were measured simultaneously in cervical cancer, corpus cancer and ovarian cancer. TPA levels were increased (more than 110 U/1) in 39% (32/82) of the cervical cancer and in 46% (6/12) of the corpus cancer patients, respectively. In ovarian cancer, TPA levels were elevated (146 U/1 or higher) in 64% (13/22). The positive rate of CEA was somewhat lower than that of TPA and LAP levels were as high as TPA. Moreover, TPA levels were correlated in clinical course. In immunohistochemical examination, TPA was present in cancer cells and absent in normal tissue.

Adenocarcinoma↗