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Biomedical subjects

H Tamada

Publications and source records attributed to H Tamada.

79 records · Page 5Linked to original sources
PubMed1980

The effect of estrogen on fetal survival in progesterone-treated ovariectomized rats.

In pregnant rats ovariectomized on Day 14 of pregnancy (sperm present=Day 1), the daily injection of 4 mg progesterone maintained normal pregnancy up to Day 17, but injured fetuses bearing hematomata on their extremities appeared very frequently thereafter, in spite of successive injections of progesterone. The addition of 0.2 microgram estradiol-17 beta to the daily dose of progesterone for two successive days between Days 15 and 18 of pregnancy prevented the occurrence of fetal injuries. Estradiol-17 beta was found to be more effective in preventing fetal damage than estrone or estriol. The results suggest that while progesterone is essential for the maintenance of pregnancy, estrogen is also necessary at the time when the conceptus elongates and becomes cylindrical.

Animals↗
PubMed1980

The effect of oestrogen on uterine plasticity in late pregnant rats.

Intrauterine pressure was recorded in anaesthetized rats on Day 20 of pregnancy by the replacement of a conceptus with a balloon. Intrauterine pressure in ovariectomized pregnant rats treated with progesterone alone was markedly higher than that in intact pregnant rats, but treatment with oestradiol as well reduced values to those of controls. Oestriol and oestrone were less effective. Uterine tolerance, tested by increasing the balloon volume until the uterus ruptured, was greater than 6.5 ml in intact rats and in ovariectomized rats treated with progesterone + oestradiol, but rupture occurred at a volume of 4.3 ml when progesterone alone was used. One of the roles of oestrogen during late pregnancy in rats may be to ensure sufficient plasticity of the uterus to allow for the increase in conceptus size.

Animals↗
PubMedDate not supplied

Detection of transforming growth factor-alpha and epidermal growth factor receptor mRNA and immunohistochemical localization of their proteins in the ovine uterus during the early implantation period.

Accumulated evidence suggests that growth factors of the epidermal growth factor (EGF) family play an important role in the murine implantation process. In the sheep, however, the uterine distribution of these factors and their receptor, EGF receptor (EGF-R), during implantation is not known. This study examined the presence of mRNA transcripts and immunohistochemical localization for transforming growth factor-alpha (TGF-alpha), the potent EGF-family member, and EGF-R in the ovine uterus during the early implantation period. By reverse transcriptase-polymerase chain reaction and sequencing of the products, the presence of TGF-alpha and EGF-R mRNA transcripts were detected in the endometrium on Days 14, 16 and 20 (Day 0 = day of mating). Immunohistochemical analysis revealed that the luminal and glandular epithelial cells and some stromal cells of the endometrium and the trophectoderm were positive for TGF-alpha and EGF-R on Days 14 and 15. Distinct staining for TGF-alpha was observed in the glandular epithelium of deep endometrial areas and strong immunoreactivity for EGF-R was found in the trophectoderm. On Days 16, 18 and 20, although the staining pattern for TGF-alpha was similar to that on the previous days, the immunoreactivity for EGF-R in the stromal cells increased and that in the gland decreased. A distinct immunoreactivity for EGF-R was found in the trophectoderm throughout the days examined. These results suggest that TGF-alpha expressed in the endometrium and trophectoderm may exert effects locally on these tissues during implantation in sheep. Furthermore, it is speculated that the temporal changes in the uterine EGF-R distribution may be related to the endometrial microvascular development.

Animals↗
PubMedDate not supplied

Secretion of testosterone and epidermal growth factor in mice with oligozoospermia caused by doxorubicin hydrochloride.

Oligozoospermia was induced experimentally by treatment with doxorubicin hydrochloride, an anticancer drug, in mice. In the testes, almost all germ cells disappeared, but Leydig cells appeared to be unchanged. The secretion of testosterone and epidermal growth factor (EGF), both of which are involved in spermatogenesis, was not influenced by the treatment. These results suggest that doxorubicin hydrochloride does not act indirectly by affecting testosterone and EGF, but produces oligozoospermia by effecting directly germ cells.

Animals↗
PubMedDate not supplied

The dipeptide alanyl-glutamine prevents intestinal mucosal atrophy in parenterally fed rats.

This study was performed to determine whether the addition of alanyl-glutamine (Ala-Gln) can prevent intestinal mucosal atrophy induced by standard solution of total parenteral nutrition (S-TPN). Forty-one male Sprague-Dawley rats weighing 250 g were randomly divided into four groups: group I was killed after overnight fasting; group II received S-TPN. The other groups received S-TPN supplemented with amino acids other than glutamine (group III) or supplemented with Ala-Gln 2 g/100 mL (group IV); both solutions were isocaloric and isonitrogenous. After 1 week of TPN the rats were killed, and the duodenum, proximal jejunum, mid-small bowel, and distal ileum were obtained for morphologic and functional analysis. Weight gain did not differ significantly among these four groups, and there was no difference in nitrogen balance between groups III and IV. Serum glutamine in group IV (102.8 +/- 13.3 mumol/dL) was significantly increased (p less than .05) compared with groups I, II, and III (66.2 +/- 3.9, 55.7 +/- 7.8, and 61.3 +/- 10.8 mumol/dL, respectively). Mucosal wet weight, protein, RNA, sucrase, and maltase of group IV were significantly increased (p less than .05) compared with groups II and III. Villus height was significantly increased (p less than .05) in the jejunum of group IV rats compared with groups II and III, but not in any other segments of the intestine. No significant changes were observed in crypt depth among all groups. Diamine oxidase in groups II, III, and IV was significantly decreased (p less than .05) compared with group I in all segments except for the ileum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Alanyl glutamine-enriched total parenteral nutrition restores intestinal adaptation after either proximal or distal massive resection in rats.

This study was designed to determine whether alanyl glutamine-containing total parental nutrition (TPN) can restore the impaired adaptive process of the remaining intestine, observed with administration of conventional TPN, after massive small-bowel resection. Seventy-four male Sprague-Dawley rats weighing 250 g were randomly divided into seven groups. Group I rats (n = 10) were killed after overnight fasting. Group II animals (n = 32) underwent massive small bowel resection (85%) with preservation of the first 15 cm of jejunum. Group III animals (n = 32) were also submitted to massive small-bowel resection with preservation of 15 cm of terminal ileum. Three different TPN solutions were prepared. Solution A was a conventional formulation that did not contain glutamine. Solution B contained 1.88 times the amino acid concentration of solution A. Solution C was prepared by adding alanyl glutamine (2 g/100 mL) to solution A. Solutions B and C were isonitrogenous and isocaloric. Each solution was infused to groups II and III, which were subdivided into groups IIA (n = 10), IIB (n = 11), IIC (n = 11), IIIA (n = 10), IIIB (n = 11), and IIIC (n = 11). After 1 week of TPN (270 kcal/kg per day), the experimental animals were killed and the intestine was taken for examination. Final body weight did not differ significantly among the groups, and there was no difference in nitrogen balance among the animals that received solution B or C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗