Biomedical subjects

M Ema

Publications and source records attributed to M Ema.

114 records · Page 7Linked to original sources

PubMedDate not supplied

Rat two-generation reproductive toxicity study of bisphenol A.

This study was conducted to determine the low-dose effects of bisphenol A (BPA) in a rat two-generation reproduction study. Groups of 25 male and 25 female Crj: CD (SD) IGS rats were given BPA at 0.2, 2, 20, or 200 microg/kg/day by gastric intubation throughout the study beginning at the onset of a 10- and 2-week premating period, in F0 males and females, respectively, and continuing through the mating, gestation, and lactation periods, for two generations. There were adult (F0, F1, F2) and postnatal day (PND) 22 (F1, F2) necropsies: the oldest F2 males and females being killed at postnatal weeks 7 and 14, respectively. No compound-related clinical signs or effects on body weight or food consumption were observed in any generation. There were no compound-related changes in surface righting reflex, negative geotaxis reflex, mid-air righting reflex, pinna detachment, incisor eruption, eye opening, testes descent, preputial separation, or vaginal opening in F1 and F2 generations, or behavior in the open field or water filled multiple T-maze in the F1 generation. No test compound-related changes in estrous cyclicity, copulation index, fertility index, number of implantations, gestation length, litter size, pup weight, pup sex ratio, pup viability, or other functional reproductive measures were noted in any generation. A few significant changes in the anogenital distance (AGD) per cube root of body weight ratio were found at 0.2 and 20 microg/kg in F1 males, at 2, 20, and 200 microg/kg in F1 females, and at 20 and 200 microg/kg in F2 females. However, the changes in the AGD were consistently small (within 5% of control values), and no continuous changes in the AGD or AGD/cube root of body weight ratio were detected. There were no compound-related changes in epididymal sperm counts or motility in F0 and F1 males. No compound-related necropsy findings or effects on organ weight including the reproductive organs were found in any generation. Histopathologic examinations revealed no evidence of compound-related changes in any organs including the reproductive organs of both sexes. The data indicate that oral doses of BPA of between 0.2 and 200 microg/kg over 2 generations did not cause significant compound-related changes in reproductive or developmental parameters in rats.

Administration, Oral↗

PubMedDate not supplied

Effects of triphenyltin chloride on implantation and pregnancy in rats.

The objective of this study was to characterize the adverse effects of triphenyltin chloride (TPTCl) during early pregnancy. Following successful mating, female rats were given TPTCl by gastric intubation at 3.1, 4.7, or 6.3 mg/kg on days 0 to 3 of pregnancy or at 6.3, 12.5, or 25.0 mg/kg on days 4 to 6 of pregnancy and were sacrificed on day 20 of pregnancy. In successfully mated females, TPTCl totally prevented implantation in a dose-dependent manner. The pregnancy rate was significantly decreased after administration of TPTCl on days 0 to 3 at 4.7 and 6.3 mg/kg and on days 4 to 6 at 12.5 and 25.0 mg/kg. In females having implantations, the numbers of implantations and live fetuses and the incidences of pre- and postimplantation loss and fetal malformations in the TPTCl-treated groups were comparable to the controls. It could be concluded that TPTCl during early pregnancy causes failure in implantation and TPTCl has greater antiimplantation effects when administered during earlier than later stages of blastogenesis.

Animals↗

PubMedDate not supplied

Reproductive effects of butyl benzyl phthalate in pregnant and pseudopregnant rats.

In our previous studies, butyl benzyl phthalate (BBP) was found to be embryolethal and teratogenic in rats. In this study, the reproductive effects of BBP were investigated in pregnant and pseudopregnant rats. Rats were given BBP by gastric intubation at 0, 250, 500, 750, or 1000 mg/kg on Days 0 to 8 of pregnancy and the pregnancy outcome was determined on Day 20 of pregnancy. The same doses of BBP were given to pseudopregnant rats, with an induced decidual cell response on Days 0 to 8 of pseudopregnancy, and the uterine weight on Day 9 served as an index of the uterine decidualization. BBP caused significant increases in the incidences of preimplantation loss in females successfully mated at 1000 mg/kg and of postimplantation loss in females having implantations at 750 mg/kg and above. Uterine decidual growth in pseudopregnant rats was significantly decreased at 750 mg/kg and above. These findings suggest that early embryonic loss due to BBP may be mediated, at least in part, via the suppression of uterine decidualization, an impairment of uterine function.

Administration, Oral↗

PubMedDate not supplied

Effects of dibutyl phthalate on reproductive function in pregnant and pseudopregnant rats.

In our previous studies, dibutyl phthalate (DBP) was found to be embryolethal and teratogenic in rats. In this study, the effects of DBP on reproductive function were investigated on pregnant and pseudopregnant rats. Rats were given DBP by gastric intubation at 0, 250, 500, 750, 1000, 1250 or 1500 mg/kg on Days 0 to 8 of pregnancy and the pregnancy outcome was determined on Day 20 of pregnancy. The same doses of DBP were given to pseudopregnant rats, with an induced decidual cell response, on Days 0 to 8 of pseudopregnancy, and the uterine weight on Day 9 served as an index of the uterine decidualization. DBP caused significant increases in the incidences of preimplantation loss in females successfully mated at 1250 and 1500 mg/kg and of postimplantation loss in females having implantations at 750 mg/kg and above. The uterine decidualization in pseudopregnant rats was significantly decreased at 750 mg/kg and above. These findings suggest that early embryonic loss due to DBP may be mediated, at least in part, via the suppression of uterine decidualization, an impairment of uterine function.

Animals↗

PubMedDate not supplied

Simple determination of tin in biological materials by atomic absorption spectrometry with a graphite furnace.

A simple and rapid determination of tin in biological materials (blood, brain, liver, kidney, etc,) by atomic absorption spectrometry (AAS) with a graphite furnace is described. Suppression of interferences by direct addition of ascorbic acid in wet-ashed biological materials was investigated for the determination of tin. This method involves no extraction with organic solvent for removal of the interferences, and therefore it is neither time consuming nor error prone, and is suitable for large sample sizes and small sample volumes. The limit of detection of this method is 0.002 microgram/mL, equivalent to a limit of detection in the materials of 0.02 microgram/g. The calibration graph is linear up to 1 microgram/mL of tin.

Animals↗

PubMedDate not supplied

Magnesium sulfate prevents alcohol-induced spasms of cerebral blood vessels: an in situ study on the brain microcirculation from male versus female rats.

Numerous studies indicate that alcohol can cause neural and vascular damage in the brain. Additional studies indicate that magnesium ions (Mg2+) possess the ability to modify vascular tone. We utilized an image-splitting television microscope recording system in an intact rat brain model in order to determine whether local (topical) application or systemic (intravenous or intra-arterial) administrations of MgSO4 exert vasodilator effects on cerebral arterioles (66-124 microns o.d.) and venules (66-137 microns o.d.). In addition, we investigated whether infusion of low doses of MgSO4 could modify cerebral vascular spasms induced by ethanol and a calcium mimic, i.e., Ba2+. Topical applications of MgSO4 (i.e., 1-100 mumol) in male and female rats produced dose-dependent dilations of cerebral arterioles and venules; male animals were clearly more sensitive to Mg2+. Systemic infusion of low doses of MgSO4 (i.e., 1.0 and 4.0 mumol/min) into the femoral vein or a branch of the internal carotid artery failed, completely, to induce changes in arterial blood pressure or diameter of arterioles and venules. However, such nonvasodilator doses of MgSO4, infused via either route, inhibited contractile responses induced by 5% Ba2+ and 10% ethanol in arterioles and venules in a dose-dependent manner in both male and female rats. Cerebral microvessels of male animals were more sensitive to inhibitory actions of Mg2+ against Ba(2+)-induced microvascular constrictions than were microvessels of females. Administration of a variety of pharmacologic antagonists as well as a cyclo-oxygenase inhibitor failed to influence either the local vasodilator effects of Mg2+ or the inhibitory actions of Mg2+. Basal plasma levels of Mg were higher in female vs. male rats (1.98 +/- 0.06 vs. 1.77 +/- 0.028 mg/dl). Systemic administration of MgSO4 in cerebral nonvasodilator doses resulted in rapid elevation of plasma Mg levels in a dose-dependent manner (e.g., 0.3-4.3 mg/dl over control levels). Plasma Mg levels were more elevated in female than male animals. It is concluded that magnesium ions can act as local vasodilators, in physiologic doses, on brain microvessels and that these divalent cations possess antispasmodic activities, in nonvasodilator doses, on intact rat brain arterioles and venules. In addition, our findings suggest that Mg2+ might be useful in the treatment and prevention of alcohol-induced brain vascular damage.

Administration, Topical↗