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Biomedical subjects

S Fabro

Publications and source records attributed to S Fabro.

At least 19 recordsLinked to original sources
PubMed1988

The development and use of a standard symphysial-fundal height growth curve in the prediction of small for gestational age neonates.

The symphysial-fundal height (SF) measurement has been routinely used in obstetrics, although its value in the prediction of small-for-gestational-age (SGA) infants remains controversial. A retrospective study was performed in order to assess the sensitivity and specificity of the SF distance and establish guidelines for its use. Local neonatal birthweight distribution and SF growth curves were developed. Eighty-six percent of 28 SGA infants demonstrated one measurement under--1 S.D. of the mean SF growth curve as did 36% of appropriate for gestational age (AGA) neonates. Seventy-five percent of SGA infants subsequently demonstrated a second measurement below--1 S.D. of the mean curve, 90% prior to 36 weeks. Only 16% of AGA exhibited such a SF growth pattern. A protocol for maximizing the use of this inexpensive and easily obtained parameter is proposed.

Adult↗
PubMed1985

Pharmacokinetics of magnesium sulfate in the sheep model.

The pharmacokinetic parameters of MgSO4 were followed in the pregnant sheep model following intravenous dosages of MgSO4 comparable to those used in the therapy of the preeclamptic woman. Hemodynamic parameters, including maternal arterial pressure, central venous pressure, systemic vascular resistance, pulmonary artery pressure, heart rate, cardiac output, cardiac index, rate pressure product, stroke volume, stroke index, blood gases, fetal arterial pressure, heart rate, and blood gases, all remain stable during the infusion of MgSO4. Biochemical changes accompanying MgSO4 infusion in these doses were evaluated. It was found that the fetal serum levels of MgSO4 were approximately 70% of those in the mother. The MgSO4 was rapidly excreted into the maternal urine and 8.9% of the MgSO4 infused was cleared by 2 hr after the termination of the infusion. MgSO4 was also excreted by the fetus into amniotic fluid. It was found that a minimum dosage of 1 mg/kg/hr of magnesium was required to achieve a magnesium level in maternal serum at the lower limit of the therapeutic range of 4 mEq/L.

Animals↗
PubMed1984

Chemical exposure of embryos during the preimplantation stages of pregnancy: mortality rate and intrauterine development.

Exposure of CD-1 mouse embryos at the eight- to 16-cell stage for 1 hour to methylmethanesulfonate (MMS; 0.25, 0.5, and 1.0 mM) produced DNA breakage and interfered with embryonic development in a dose-related manner. MMS-exposed blastocysts were transferred to oviducts of untreated recipient female mice, and the conceptuses were allowed to develop to term. MMS exposure resulted in an increased intrauterine death rate, although the number of implantation sites was not decreased. Surviving MMS-treated offspring showed intrauterine growth retardation, but there was no increase in the incidence of gross abnormalities. Intrauterine growth retardation, without an increase in gross abnormalities, was also observed in the offspring of pregnant New Zealand White rabbits dosed during the preimplantation stages of pregnancy with an "environmental cocktail" composed of ethanol, nicotine, caffeine, sodium salicylate, and dichloro-diphenyl-trichloro-ethane (DDT). When the compounds were tested individually, nicotine and DDT were the only two that produced intrauterine growth retardation. DDT-treated 8-day rabbit conceptuses were smaller than controls and showed abnormal persistence of preimplantation proteins in the yolk sac fluid. These results suggest that exposure to chemicals during the preimplantation stages of pregnancy may result in a cessation of growth and development before implantation or during later intrauterine development. Damage can be repaired but it may result in offspring that show intrauterine growth retardation without gross abnormalities.

Animals↗
PubMed1983

In vitro exposure of male and female mice gametes to cadmium chloride during the fertilization process, and its effects on pregnancy outcome.

The effect of cadmium chloride (Cd) on gamete fusion in vitro was evaluated, with further observations of the embryonic development and assessment of the pregnancy outcome of the in vitro fertilized mice. Oocytes were recovered from superovulated B6C3F1 females. Of 1210 control oocytes, 53.2% cleaved into two-cell stage embryos. Of these, 46.6% developed into blastocyst stage embryos which were then surgically transferred to pseudopregnant female CD-1 mice. Of a total of 63 implanted embryos, 8 (12.7%) developed in utero to live fetuses. Teratological examinations of these "test-tube" mice revealed no signs of abnormalities caused by in vitro culture. Male and female gametes were exposed to 0.4, 0.8, or 1.6 microM of Cd and a decrease in sperm motility was noted in the 1.6 microM group. Nevertheless, even in the highest concentration used, 56.4% of the ova cleaved into the two-cell stage, thus indicating no effect of Cd on initial gamete interaction. Gametes that had been treated with 0.4 and 0.8 microM Cd developed to blastocysts at rates comparable to that of the controls. In the 1.6 microM group, however, only one (3.2%) of the two-cell embryos developed to the blastocyst stage. Blastocysts from 0.4 microM Cd-treated gametes were then transferred to surrogate dams. Statistically significant blastocyst losses were recorded during the implantation period, whereas the pregnancy rate and the numbers of resorbed and live fetuses, were comparable to those of the controls. The offspring exhibited no malformations, and their body weights remained within the control values.

Animals↗
PubMed1982

The relative teratogenic index and teratogenic potency: proposed components of developmental toxicity risk assessment.

Teratogenicity tests should provide answers to three questions: (1) Can the agent induce developmental defects? ("teratogenic potential"); (2) What are the effective doses? ("teratogenic potency"); and (3) Are effective doses below adult toxic doses? ("teratogenic hazard"). The answers to (2) and (3) should be quantitative in nature, but there are no accepted parameters to express these properties. In this paper we propose parameters for the description of teratogenic potency and hazard in quantitative terms. Derivation and calculation of the parameters are illustrated by the analysis of adult lethality and teratogenicity data of eight structurally related anhydrides and imides, following testing in the CD-1 mouse. Teratogenicity was evaluated following treatment on Days 8-10 of gestation, using an average of four dose groups per compound and at least 10 dams per group. Adult lethality was estimated following a similar 3-day dosage schedule with an average of 6 dose groups per compound and at least 8 animals per group. Dose-response relationships of teratogenicity were fitted to a probit model from which tD50 (median effective dose), and other effective doses were computed. It is proposed that tD05, as a minimum teratogenic dose, best represents teratogenic potency. In this study, potency ranged from 0.17 mmol/kg/day for phenytoin to 5.2 mmol/kg/day for ethosuximide. In order to measure teratogenic hazard a ratio between adult toxic (lethality was chosen as the most appropriate measure) and teratogenic responses was made. Since the dose-response slopes of lethality and teratogenicity were different, a simple ratio between median effective doses could not be used. It is shown that a ratio of LD01 to tD05 provides a "Relative Teratogenic Index" (RTI) which reflects the teratogenic hazard of a test agent. The following RTI values (LD01/tD05) were computed in this study: phthalic anhydride, 0.9; phensuximide, 1.0; succinic anhydride, 1.0; ethosuximide, 1.2; phenytoin, 1.6; phenacemide, 3.3; trimethadione, 4.0; and sodium valproate, 4.1. For these data, tD05 and RTI clearly represent the differing teratogenic potencies and hazards of the tested compounds. it is suggested that these parameters may be useful in comparative teratogenicity studies and may be valuable components of developmental toxicity risk assessment.

Abnormalities, Drug-Induced↗
PubMed1981

Quantitation of rat embryonic development in vitro: a morphological scoring system.

In order to realize the maximum potential of whole-embryo culture techniques, definitive parameters must be developed for the quantitative estimation of embryonic growth and development. An objective scoring system has been devised which provides a precise measure of morphological development. Examination of rat conceptuses from dams on pregnancy days 10, 11, 12, and 13 (sperm positive = day 1) led to the selection of 17 morphological features for use in the system. Up to six developmental stages of each feature were defined and assigned scores of 0 to 5. The numerical total of scores for an individual embryo is taken as the overall morphological score (MS). The system was applied prospectively to 103 Sprague-Dawley rat conceptuses aged 9 to 12.7 days (0 = time of copulation). The variation of score with embryonic age (EA, days) was highly linear: MS = 202.28 + 20.932 EA (R2 = 0.991). Thus, the morphological score can be used to compute apparent embryonic age, and the calculated standard error of prediction is +/- 2.2 hrs. The number of somites (SN) was also found to vary linearly with age over this period: SN = -126.23 + 13.217 EA (R2 = 0.982), and could be used to estimate development. However, the standard error for prediction of apparent embryonic age is greater (+/- 3.1 hours) than that for morphological score, and this single feature will not necessarily reflect overall development. Several parameters were examined as estimates of embryonic growth, as distinct from development. Yolk sac diameter, crown-rump length, and head length were found to vary with EA as quadratic functions over this time. Total embryonic protein increased logarithmically with EA and was considered to be the most suitable measure of embryonic growth. Use of the morphological scoring system in embryo culture experiments provides a precise index of embryonic development, aids the detection of retardation or dysmorphogenesis of specific primordia, and allows a quantitative comparison of development and growth.

Animals↗
PubMed1979

Ethanol embryotoxicity: direct effects on mammalian embryos in vitro.

Exposure to ethanol retards growth and differentiation in cultured rat embryos during organogenesis. The development of untreated embryos is indistinguishable from growth in utero. These data suggest that the hypoplastic features of children born to chronically alcoholic mothers are due, at least in part, to a direct action of ethanol, which causes reduced embryonic cellular proliferation early in gestation.

Animals↗