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Biomedical subjects

S Takagi

Publications and source records attributed to S Takagi.

At least 505 records · Page 28Linked to original sources
PubMed1987

Brain neurotransmitter receptor alterations in offspring of rats exposed to phenobarbital, phenytoin or their combination during pregnancy.

Neurotransmitter receptor binding was studied in the progeny of rats exposed to phenobarbital (80 mg/kg), phenytoin (80 mg/kg) or their combination daily from 5 to 20 days of gestation. At 22 days postnatally, female pups in all treated groups showed decreased binding of [3H]spiroperidol to striatal membranes. A decreased binding of [3H]diazepam to frontal cortical membranes was observed in the female pups of rats exposed to phenytoin or the combination. The Scatchard analysis of data from the affected groups revealed a decrease in the maximum number of dopamine and benzodiazepine receptor sites and no change in their affinities. The binding of [3H]spiroperidol or [3H]diazepam was not altered significantly in any of the drug-treated male pups. Also, no significant change in the binding of [3H]serotonin or [3H]quinuclidinyl benzilate to frontal cortical membranes was observed in any of the treated groups. At 60 days postnatally, no significant change in the binding of any of the above ligands was evident. The above prenatal drug exposures appear to cause transitory subsensitivity of dopamine and benzodiazepine receptors in rats.

Animals↗
PubMed1987

[Effects of RU38486, an antiprogesterone agent, on endometrium, fertilized ovum and serum sex steroid levels in rats].

Effects of antiprogesterone RU38486 were studied in rats. The synthetic compound effectively (100%) inhibited implantation when administered on day 2 as well as on day 4 postconception (2.5mg/kg, in glycerol). This treatment, however, did not alter circulating estradiol and progesterone levels. Fertilized ovum yielded on day 4 from the uterine cavity showed normal morphology including adequate progress in cell division. A light microscopic study of the endometrium showed decreased cytoplasmic vacuole formation but estrogenic effects were apparently preserved. These data suggest that administration of RU38486 immediately after conception could successfully prevent implantation without altering early luteotropic functions in rats. Also the high dose of the compound was found to have no significant toxic effects on fertilized ovum, indicating that the anticonceptional action of RU38486 mainly functions at the uterine endometrial level.

Animals↗
PubMed1987

A study of anti-progestational compound RU38486 action on the estrogen-induced enlargement of the rat pituitary gland.

Long term administration of estradiol to intact and ovariectomized female rats caused enlargement of the pituitary gland. This process was partially antagonized in intact animals when antiprogestational compound RU38486 was given concomitantly. In ovariectomized rats, however, this effect of RU38486 was not apparent. Since administration of the compound to ovariectomized animals did not alter estrogen-receptor translocation or estrogen induced hypervascularity in the pituitary gland, this inhibitory effect of RU38486 seems not to be exerted through estrogen-receptor binding antagonism but rather due to a progesterone receptor blockade at the hypothalamic-pituitary axis.

Adenoma↗
PubMed1986

High homology is present in the primary structures between murine senile amyloid protein (ASSAM) and human apolipoprotein A-II.

The primary structure of a murine senile amyloid protein (ASSAM) was determined. The protein consists of a single polypeptide chain of 78 amino acid residues. The amino-terminus is blocked with pyrrolidone-carboxylic acid. The sequence differs from that of the known murine amyloid A protein and is highly homologous to human apolipoprotein (apo) A-II. The result indicates that the putative precursor of the senile amyloid protein is apo A-II in mice.

Amino Acid Sequence↗
PubMed1986

Evaluation by pulsed Doppler echocardiography of the atrial contribution to left ventricular filling in patients with DDD pacemakers.

To evaluate the significance of the left atrial (LA) contribution to left ventricular (LV) filling in cardiac pacing, LV inflow velocity was recorded with pulsed Doppler echocardiography in 20 patients with a DDD pacemaker. The pacemaker was programmed to atrioventricular (AV) sequential pacing with AV intervals of 50, 100, 150, 200 and 250 ms, and then to VVI pacing at a fixed rate of 70 beats/min. To evaluate the relative changes of LV filling volume in individual patients, the percent change in time-velocity integral of LV inflow velocity in each pacing mode was calculated as the ratio to that of AV sequential pacing with an AV interval of 150 ms. To estimate the degree of LA contribution to LV filling, the ratio of time-velocity integral during LA ejection phase to that during total LV filling phase was measured at the optimal AV interval. The percent LV inflow volume in AV sequential pacing was 74% for an AV interval of 50 ms, 87% for 100 ms, 98% for 200 ms and 90% for 250 ms. The percent LV inflow volume in VVI pacing was 72%. The percent LV inflow volume at AV intervals of 150 ms was significantly greater than that at an AV interval of 50, 100 and 250 ms, and in VVI pacing (p less than 0.05). The degree of LA contribution to LV filling showed a positive correlation with the percent increase of LV inflow volume with mode conversion from VVI to AV sequential pacing (p less than 0.005) and also with age (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Immunoregulatory function and expression of OKT17 antigen of adult T-cell leukemia cells.

Research was carried out on neoplastic T-cells taken from 10 cases of Japanese adult T-cell leukemia (ATL) in regard to their immunoregulatory activity on pokeweed mitogen (PWM)-driven immunoglobulin (Ig) production and their differentiation antigens. ATL cells were reactive with OKT3, OKT4 and OKT11 in most cases; however, the ATL cells from one case did not react with OKT11 nor formed E-rosettes. ATL cells of three cases were reactive with OKT8 as well as OKT4. In six cases, the ATL cells were reactive with OKT17 and coincidentally displayed suppressor activity on Ig production. The cells of the remaining four cases did not have such reactivity with OKT17 or suppressor activity. Moreover, the OKT17(+) ATL cells from one case sorted by FACS 440 demonstrated suppressor activity, while the OKT17(-) ATL cells did not. These results indicated that ATL cells with suppressor activity had OKT3(+), OKT4(+), OKT17(+) phenotype.

Adult↗
PubMed1986

Clinical application of the perineal scan: prepartum screening for cord presentation.

Real-time linear-array ultrasonographic scanning was performed from the perineum on 12 primiparous term women with the fetus in breech or foot presentation. Scanning was done with the patient initially in lithotomy position and then in semi-Trendelenburg position if a better view was required. The technique appears to be excellent for visualization of the forelaying umbilical cord even when the cervix is closed and is not affected by the acoustic shadow of the public arch. The information obtained by the scanning may be of value in avoiding or improving perinatal mobility of breech/footling fetuses and in providing better perinatal management.

Breech Presentation↗
PubMed1986

Plasticity and rigidity of differentiation of brain vesicles studied in quail-chick chimeras.

Transplantation of a piece of the alar plate of the prosencephalon or of the rhombencephalon of quail embryos into the roof of the mesencephalon of chick embryos was carried out at 7-10 somite stage. Results obtained were: the transplanted alar plate of the prosencephalon differentiated into tissue closely resembling the tectum when the transplants were integrated into the host mesencephalon; in all the cases, the alar plate of the rhombencephalon did not differentiate into tectum-like structure, but into rhombencephalic descendants. We conclude that the alar plate of the prosencephalon at 7-10 stage is not definitively determined and may retain an ability to differentiate into the optic tectum, whereas the prospective fate of the rhombencephalon has already been determined at 7-10 stage.

Animals↗