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Biomedical subjects

M Ichijo

Publications and source records attributed to M Ichijo.

At least 127 records · Page 7Linked to original sources
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

Prevention of HTLV-I transmission through the breast milk by a freeze-thawing process.

Fifteen human breast milk samples obtained from mothers seropositive for human T-cell lymphotropic virus type-I (HTLV-I) antigen were kept frozen overnight at -20 degrees. Each milk sample was then co-cultivated with cord lymphocytes obtained from 15 anti-HTLV-I antibody-negative mothers. No HTLV-I antigen-positive cells were detected among the cord lymphocytes subjected to co-cultivation. These results suggest that thawing of frozen breast milk may prevent HTLV-I transmission from mother to child via breast milk.

Antigens, Viral↗
PubMed1986

[Fundamental and clinical studies of imipenem/cilastatin sodium in the field of obstetrics and gynecology].

Imipenem (MK-0787), a new carbapenem antibiotic, combined with cilastatin sodium (MK-0791), was studied clinically and microbiologically. The following results were obtained: Concentrations of MK-0787 in the plasma and internal genital tissues were measured at 1 hour after an intravenous drip infusion of MK-0787/MK-0791 (500 mg/500 mg) for 30 minutes. Mean plasma levels higher than 11.8 micrograms/ml and mean tissue levels higher than 2.3 micrograms/g were observed. When its MIC values are considered, MK-0787/MK-0791 appeared to be bactericidal against many Gram-positive and Gram-negative bacteria except some Pseudomonas sp. and Enterococcus faecium. Clinical effects of the therapy with MK-0787/MK-0791 (500 mg/500 mg) using a drip infusion twice daily were evaluated in 3 patients with pyometra and 3 patients with Bartholin's gland abscess. Clinical responses were good in 5 of the 6 patients. One patient with pyometra due to E. coli didn't respond to the therapy. No side effects or abnormal laboratory findings due to the drug were noted.

Abscess↗
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↗
PubMed1986

[Pharmacokinetics of adriamycin vaginal suppository in uterine cervical cancer].

Vaginal suppositories of Adriamycin (ADM, 5 mg), for reducing the capacity for repair from sublethal damage of X-ray-irradiated cells, were prepared using Wipepsol S-55 as the vehicle, and were intravaginally administered to patients with advanced uterine cervical cancer, and their pharmacokinetics and clinical effects were studied. The ADM concentration in the uterine cervical cancer tissues indicated high levels (17 to 566 micrograms/g), and migration into the cardinal ligament and regional lymph nodes was noted. However, little ADM was detected in serum (0 to 0.14 micrograms/g), probably because of its molecular weight and excellent tissue absorbance, and no side effects, such as cardiotoxicity and myelosuppression due to consecutive administration were detected. Histologically, the effect obtained when administered alone was limited, administration in combination with radiotherapy being more effective. Accordingly, radiotherapy of advanced uterine cervical cancer with concomitant administration of ADM vaginal suppositories seems to bring about a more powerful antitumoral effect with fewer systemic side effects.

Cervix Uteri↗
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↗