Biomedical subjects

S Sassa

Publications and source records attributed to S Sassa.

257 records · Page 15Linked to original sources

PubMedDate not supplied

Effects of estrone with or without medroxyprogesterone acetate on the femur in aged rats.

In an attempt to define the efficacy of hormone replacement therapy in postmenopausal osteoporosis, we investigated the effects of estrone with or without medroxyprogesterone acetate on the bone mineral density of the femur of aged rats, of which plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol were markedly reduced in comparison with those of younger rats. Although additional sex hormones had little effect on the plasma levels of gonadotropins, chronic administration of estrone significantly enhanced the bone mineral density of femur in aged animals.

Aging↗

PubMedDate not supplied

Effects of a new clerodane diterpenoid isolated from propolis on chemically induced skin tumors in mice.

Propolis is a resinous material gathered by honey bees from the buds and bark of certain trees and plants, and used inside their hives. Characteristic components of propolis are many kinds of flavonoid aglycones. The methanol extract of a Brazilian propolis was fractionated by HPLC, and a tumoricidal substance was isolated and characterized as a new clerodane diterpenoid (PMS-1) with a molecular formula of C20H32O3 (MW: 320). We investigated the effects of PMS-1 on skin tumorigenesis and the development of skin tumors induced by 7,12-dimethylbenz(a)anthracene application on mouse back skin. It was tentatively concluded that PMS-1 reduced the incidence of skin tumors by inhibition of DNA synthesis in a de novo pathway, and suppressed the growth of the tumors by decreasing DNA synthesis in a salvage pathway.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Additional effects of medroxyprogesterone acetate on mammary tumors in oophorectomized, estrogenized, DMBA-treated rats.

Although hormone replacement therapy not only relieves vasomotor symptoms but also reduces cardiovascular disease and osteoporosis, long-term estrogen therapy increases the risk of endometrial and/or mammary cancer. We investigated the effects of conjugated estrogens with or without medroxyprogesterone acetate in oophorectomized, 7,12-dimethylbenz(a)anthracene-treated rats. Chemically induced mammary carcinogenesis was completely suppressed by the simultaneous oophorectomy, but conjugated estrogens replacement with or without medroxyprogesterone acetate markedly stimulated mammary carcinogenesis in the ovariectomized rats. The chronic administration of conjugated estrogens and medroxyprogesterone acetate markedly reduced the activities of thymidylate synthetase and thymidine kinase and bromodeoxyuridine-immunoreactive (S-phase) cells in mammary tumors. These results indicate that the treatment using conjugated estrogens with or without medroxyprogesterone acetate may promote the mammary carcinogenesis in postmenopausal women but the chronic administration of medroxyprogesterone acetate may alter the development of established mammary cancer.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Effects of tamoxifen on mammary tumors and bone in 7,12-dimethylbenz-(a)anthracene-treated rats.

We investigated the effects of tamoxifen on the growth of 7,12-dimethylbenz(a)anthracene induced rat mammary tumors, the activity of thymidylate synthetase and thymidine kinase (key enzymes involved in de novo and salvage pathways for pyrimidine nucleotide synthesis), and also their gene expression. The effects on immunohistochemistry using bromodeoxyuridine in the tumors and bone mineral density of the femur in rats were also studied. Chronic administration of tamoxifen markedly reduced the expression of thymidylate synthetase mRNA, followed by a reduction in enzyme activity and S-phase cells in the mammary tumors, and significantly enhanced the bone mineral density. Tamoxifen not only attenuated bone loss in aging but also enhanced bone volume in mammary tumor-bearing rats in which tumor growth was suppressed via both the de novo and salvage pathways for pyrimidine nucleotide synthesis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Conservative management for perimenopausal women with uterine leiomyomas using Chinese herbal medicines and synthetic analogs of gonadotropin-releasing hormone.

The effects of a long-term intranasal administration of each of the gonadotropin-releasing hormone analogs, buserelin and nafarelin on uterine leiomyomas after conservative treatment using Chinese herbal medicines, Keishi-bukuryo-gan and Shakuyaku-kanzo-to were investigated in 30 perimenopausal women with leiomyomas. Hypermenorrhea and/or dysmenorrhea as a chief complaint was moderately improved by the treatment using Chinese herbal medicines in more than 60% of the patients with less than fist-sized leiomyomas, but not the over fist-sized. Afterwards, continuous treatment using analogs produced a long-term reduction in leiomyomas (less than 60%) along with decreases in the serum levels of luteinizing hormone, follicle-stimulating hormone, estradiol, and the tumor marker CA-125, and adverse effects including slight boneloss. Long-term treatment using Chinese herbal medicines and gonadotropin-releasing hormone analogs for the management of uterine leiomyomas could be beneficial for patients a few years before menopause, though possible side effects of this treatment should be monitored.

Adult↗