Biomedical subjects

K Morishige

Publications and source records attributed to K Morishige.

8 recordsLinked to original sources

PubMed1992

Intraventricular administration of thyrotrophin-releasing hormone (TRH) suppresses prolactin secretion and synthesis: a possible involvement of dopamine release by TRH from rat hypothalamus.

The administration of thyrotrophin-releasing hormone (TRH) causes a variety of dopamine-related biological events. To understand the specific role of TRH on rat hypothalamic dopamine neurones, we examined the in-vivo effects of intraventricular (i.c.v.) infusion of TRH on the release and synthesis of prolactin in the rat pituitary gland and on the changes in binding of [3H]MeTRH and dopamine turnover rates in rat hypothalamus. We have also examined the in-vitro effects of TRH on the release of [3H]dopamine from dispersed tuberoinfundibular dopamine neurones. Female rats were treated with i.c.v. infusions of 1 mumol TRH/1 daily for 1, 3 and 7 days using Alzet osmotic pumps. Following 7 days of treatment the serum prolactin concentrations were significantly decreased. A reduction in hypothalamic TRH-binding sites (Bmax) was also apparent but the dissociation constant (Kd) was unaffected. Northern blot analysis of total RNA isolated from the pituitary glands of control animals using 32P-labelled prolactin cDNA as a probe indicated the presence of three species of prolactin gene transcripts of approximately 3.7, 2.0 and 1.0 kb in size, and these were decreased by TRH treatment. We examined the turnover rate of dopamine in the rat hypothalamus when TRH was administered i.c.v. for 7 days. There was a significant increase in 3,4-dihydroxyphenylacetic acid/dopamine ratio with TRH treatment. Moreover, exposure to TRH stimulated [3H]dopamine release from rat tuberoinfundibular neurones in a time- and dose-dependent manner. Dopamine receptor antagonists such as SCH23390 and (-)sulpiride, and other neuropeptides such as vasoactive intestinal peptide and oxytocin did not affect TRH-stimulated [3H]dopamine release.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗

PubMed1991

Involvement of transforming growth factor alpha/epidermal growth factor receptor autocrine growth mechanism in an ovarian cancer cell line in vitro.

Although transforming growth factor (TGF) alpha and epidermal growth factor (EGF) receptor (EGFR) autocrine mechanism is widely demonstrated in many kinds of cancers, its biological significances still remain circumstantial. We critically assessed the significance of this mechanism on the growth of an ovarian cancer cell line. Northern blot analysis in polyadenylated RNA isolated from cells by using 32P-labeled pre-TGF alpha, EGRF, and prepro-EGF complementary DNAs as probes revealed that pre-TGF alpha and EGFR but not prepro-EGF gene transcripts were expressed in the cell. TGF alpha and EGFR but not EGF proteins were observed by immunocytochemical stainings, using monoclonal antibodies against human TGF alpha, EGFR, and EGF, respectively. This cell line possessed a class of high affinity EGF receptor by 125I-EGF binding studies; Kd being 2.9 x 10(-10) M and Bmax to be 7.7 x 10(4) sites/cell. As much as 1.12 +/- 0.14 ng (SD; n = 3)/10(7) cells/24 h of TGF alpha was secreted in the conditioned media. These results suggested the expression of a TGF alpha/EGFR autocrine mechanism in this cell line. We, therefore, assessed the biological significance of this mechanism on the growth of this cell line in serum-free monolayer cell cultures. Although 0.1, 1.0, and 10 nM concentrations of TGF alpha did not show significant growth promotion, monoclonal antibodies against TGF alpha and EGFR but not EGF significantly inhibited cell growth. All these data suggested the biological importance of a TGF alpha/EGFR autocrine mechanism on the growth of this cell line in vitro.

Antibodies, Monoclonal↗

PubMed1991

Importance of transforming growth factor alpha/epidermal growth factor receptor autocrine growth mechanism in an ovarian cancer cell line in vivo.

We have elucidated the importance of a transforming growth factor (TGF) alpha and epidermal growth factor receptor autocrine mechanism on the growth of a human ovarian serous cystadenocarcinoma-derived cell line (SHIN-3) in vitro. In this study, we studied the biological significance of this autocrine mechanism in vivo using female athymic nude (nu/nu) mice. We measured the mouse plasma epidermal growth factor and TGF alpha levels by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. Plasma epidermal growth factor concentrations were remarkably decreased by sialoadenectomy (Sx): 410 +/- 65 (SE) pg/ml (n = 10) in intact animals; and undetectable in Sx mice (n = 5). Plasma TGF alpha levels were 90 and 40 pg/ml in intact and in Sx animals, respectively. Ten million SHIN-3 cells inoculated into nu/nu mice formed tumors in 100% of mice, and tumors grew progressively. Implantabilities and tumor growth rates of inoculated cells were not affected by Sx and even by Sx and anti-mouse epidermal growth factor antibody treatment. However, anti-TGF alpha monoclonal antibody (mAb) administered to SHIN-3 cell-inoculated Sx animals drastically reduced the tumor growth. Although 10(7) SHIN-3 cells formed tumors in this group, tumor growth was significantly inhibited by 10 micrograms of anti-TGF alpha mAb given 3 times a week, and growth inhibitions were more by 20 micrograms of anti-TGF alpha mAb. Moreover, as aggressive tumor growth as that in Sx animals was resumed by the cessation of anti-TGF alpha mAb treatments. All these data suggested the biological importance of a TGF alpha/epidermal growth factor receptor autocrine mechanism on the growth of this cell line in vivo.

Animals↗

PubMed1991

Evidence for the involvement of transforming growth factor alpha and epidermal growth factor receptor autocrine growth mechanism in primary human ovarian cancers in vitro.

We examined 35 primary human ovarian adenocarcinomas for the presence of epidermal growth factor (EGF) receptor (EGFR) in plasma membranes from cancer tissues by using 125I-EGF as a ligand. Specific 125I-EGF bindings were observed in 20 (57%) of these 35 cases. Scatchard analysis showed a class of high affinity EGF receptor: Kd 5.0 +/- 1.0 x 10(-10) M; Bmax, 83.3 +/- 12.1 fmol/mg protein (mean +/- SE, n = 20). Northern analysis in polyadenylated RNA from 15 EGFR(+) cancers using pretransforming growth factor alpha (pre-TGF alpha), prepro-EGF complementary DNA, and pE7, a complementary DNA clone of human EGFR, as probes revealed that pre-TGF alpha and EGFR mRNAs but not prepro-EGF mRNA were expressed in all cases examined. Immunocytochemical studies using monoclonal antibodies (mAbs) against TGF alpha, EGF, and EGFR showed that TGF alpha and EGFR but not EGF proteins were present on ovarian cancer cells in all cases. These data suggested a possible TGF alpha/EGFR autocrine mechanism in EGFR(+) ovarian cancers. We, therefore, examined the biological significance of this autocrine mechanism by using primary monolayer cell cultures. In primary cultures from EGFR (+) cancers, TGF alpha added to the culture medium stimulated the [3H]thymidine incorporation dose dependently. Moreover, the addition of mAbs against TGF alpha and EGFR but not EGF inhibited [3H]thymidine incorporation dose dependently in EGFR(+) cancer cells. On the other hand, in primary cultures from EGFR(-) cancers, TGF alpha and anti-TGF alpha, -EGFR, and -EGF mAbs did not show any effects on [3H]thymidine incorporation. All these results suggested the possible crucial role of a TGF alpha/EGFR autocrine growth mechanism in primary human ovarian cancers which express EGFR.

Adenocarcinoma↗

PubMed1991

Epidermal growth factor attenuates cell proliferation by down-regulating the transforming growth factor-beta receptor in the osteoblastic cell line MC3T3-E1.

We investigated the role of transforming growth factor beta 1 (TGF-beta 1) in growth regulation of the murine osteoblastic cell line, MC3T3-E1. We detected TGF-beta activity in the conditioned medium of MC3T3-E1 cells and its activity was increased by acid treatment of the bioassay system using CC1 64 cells. Northern blot analysis revealed the expression of TGF-beta 1 precursor messenger ribonucleic acid (mRNA). MC3T3-E1 cells possessed a single class of high affinity TGF-beta 1 receptor (2.8 x 10(4) sites per cell, Kd = 196 pM). Cross-linking studies revealed three specific TGF-beta receptors with molecular masses of 65, 95 and 280 kDa. Both TGF-beta and epidermal growth factor (EGF) stimulated [3H]-thymidine incorporation into cells. EGF decreased the number of TGF-beta receptor dose-dependently, and pretreatment of cells with 10 nM EGF attenuated cell growth by TGF-beta. All these data suggested that TGF-beta might be an autocrine growth factor in murine osteoblastic MC3T3-E1 cells and that EGF might modulate the growth of cells by down-regulating the TGF-beta receptor level.

Animals↗

PubMed1991

Decrease in epidermal growth factor receptor and its messenger ribonucleic acid levels in intrauterine growth-retarded and diabetes mellitus-complicated pregnancies.

We measured the amounts of epidermal growth factor receptor (EGFR) in plasma membranes from human placentas at term delivery in three groups: appropriate for gestational age (AGA), intrauterine growth-retarded (IUGR), and diabetes mellitus-complicated (DM) pregnancies. At the same time, EGFR mRNA levels were examined in three groups by dot and Northern blot analyses. Binding studies were performed using 125I-labeled human EGF as a ligand, and two classes (high and low) of binding sites were found in all specimens. Although dissociation constants (Kd) were not significantly different among three groups, the number of binding sites was significantly decreased in IUGR and DM placentas compared to that in the AGA group. Total cellular RNA was isolated from a part of the placentas used for binding studies using the guanidinium CsCl method, denatured, and dot blotted onto nitrocellulose filter. Poly(A)+ RNA was selected from the total RNA, electrophoresed in 1% agarose gel, and transferred onto nitrocellulose filters. Then, hybridization with 32P-labeled pE7 (a cDNA of EGFR), autoradiography, and densitometry were performed. The amounts of mRNA hybridized with pE7 were reduced in IUGR and DM placentas compared to that in the AGA group. The molecular sizes of EGFR mRNA were 10 and 5.6 kilobases in all three groups. These results suggest possible physiological actions of EGF on adequate feto-placental growth and development in human pregnancy.

Diabetes Mellitus↗

PubMed1990

Invention of anti-Leishmania drugs on the basis of the nucleoside structures.

3'-Deoxy-3'-fluoroinosine is a potent inhibitor for the growth of the promastigote form of Leishmania tropica and Leishmania donovani. In culture, the EC50 values of 3'-deoxy-3'-fluoroinosine are 2.3 x 10(-7) and 1.0 x 10(-6) M for the promastigotes of L. tropica and L. donovani, respectively. It is less toxic towards mouse mammary tumor FM3A cells: the EC50 value is 2.0 x 10(-4) M. 3'-Deoxy-3'-fluoroinosine is metabolized by Leishmania promastigotes to give 3'-deoxy-3'-fluoroadenosine-5'-triphosphate. This metabolic conversion provides a mechanism for the parasite-selective toxicity of 3'-deoxy-3'-fluoroinosine.

Animals↗

PubMed1989

The use of serum TA-4 in monitoring patients with malignant transformation of ovarian mature cystic teratoma.

The development of cancer in mature cystic teratomas of the ovary is rare and sometimes difficult to detect because of sampling errors. Six cases of squamous cell carcinoma arising in ovarian mature cystic teratomas were studied, five of which showed an elevated level of a squamous cell carcinoma-associated antigen, TA-4, in the sera obtained preoperatively; the preoperative determination was not performed in the sixth case. However, no elevated TA-4 level was detected in the sera of 28 patients with mature cystic teratomas of the ovary. Moreover, serial determination of the serum TA-4 level showed a good correlation between the clinical course and the serum TA-4 level. Interestingly, an abnormal TA-4 level preceded the clinical detection of recurrence by 2 months in two patients. Thus, determination of the serum TA-4 concentration may be useful for diagnosing and monitoring patients with squamous cell carcinoma arising in mature cystic teratomas of the ovary.

Adult↗