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The cytosolic glucocorticoid receptor of 21st gestational day rat epiphyseal chondrocytes has been evaluated. The receptor, a single class of glucocorticoid binding component approached saturation, utilizing [3H]triamcinolone acetonide ([3H]TA) as the radiolabeled ligand, at approximately 1.8-2.0 x 10(-8) M. The dissociation constant (Kd) reflected high-affinity binding, equaling 4.0 +/- 1.43 x 10(-9) M (n = 7) for [3H]TA. The concentration of receptor estimated from Scatchard analysis was approximately 250 fmol/mg cytosolic protein and when calculated on a sites/cell basis equalled 5800 sites/cell. The relative binding affinities of steroid for receptor were found to be triamcinolone acetonide greater than corticosterone greater than hydrocortisone greater than progesterone greater than medroxyprogesterone acetate much greater than 17 alpha-hydroxyprogesterone much greater than testosterone greater than 17 beta-estradiol. Cytosolic preparations activated in vitro by warming (25 degrees C for 20 min) were shown to exhibit an increased affinity for DNA-cellulose. 46% of the total specifically bound activated ligand-receptor complex was bound to DNA-cellulose. Cytosol maintained at 0-4 degrees C in the presence of 10 mM molybdate or activated in vitro in the presence of molybdate, bound to DNA-cellulose at 8 and 10% respectively. DEAE-Sephadex elution profiles of the nonactivated receptor were indicative of a single binding moiety which eluted from the columns at 0.4 M KCl. Elution profiles of activated receptor were suggestive of an activation induced receptor lability. The 0.4 M KCl peak was diminished, while a concomitant increase in the 0.2 M KCl peak was only modestly discernible. Evaluation of endogenous proteolytic activity in chondrocyte cytosol using [methyl-14C]casein as substrate show a temperature-dependent proteolytic activity with a pH optimum of 5.9-6.65. The proteolytic activity was susceptible to heat inactivation and was inhibitable, by 20 mM EDTA. The sedimentation coefficient of the nonactivated receptor was 9.3s (n = 6) on sucrose density gradients and exhibited steroid specificity and a resistance to activation induced molecular alterations when incubated in the presence of 10 mM molybdate. Receptor activation in vitro, in the absence of molybdate induced an increased receptor susceptibility to proteolytic attack and/or enhanced ligand receptor dissociation as evidenced by a diminution of the 9.3s binding form without a concomitant increase in 5s or 3s receptor fragments.

In the late 1950s, we initiated an investigative program that appeared to be completely unrelated to placental transport, yolk sac dysfunction, or teratogenesis. We were interested in the changing pattern of tissue antigens throughout embryonic development and especially in the importance of cell surface macro-molecules in embryonic development. As a part of that project, we raised numerous heterologous antisera against embryonic and adult rat tissues. During localization studies with these antisera in pregnant rats, we discovered that rabbit anti-rat kidney serum was a potent teratogenic agent (Fig. 14. 1).1 Kidney antiserum produced teratogenesis growth retardation, and embryonic death during the entire perid of early organogenesis. The higher the dose, the greater the effect (Table 14. 1).

In Reply .—We appreciate the historical perspective that Maberly provides the readers of Pediatrics concerning the obstacles that have confronted scientists when new ideas or discoveries have been proposed to the scientific and lay communities.1,2 Maberly reflects on the lengthy battle that lasted more than a century before iodination of salt was established as an acceptable public health practice; even after acceptance occurred, there were a few doomsday predictors of catastrophe or poisonings. We remember from …

In Reply .— We thank Dr Merritt and his colleagues for their original publications about a case of childhood lead poisoning associated with the ingestion of a lead-contaminated toy necklace1,2 and Dr Merritt for the letter above. He disagrees with our assessment that this child had chronic lead exposure rather than simply 1 “acute” exposure from the swallowed medallion and offer the fact that a thorough environmental investigation failed to uncover a source of lead exposure as evidence that this child's problem was caused exclusively by this ingestion. They also point in their letter to their ongoing neurocognitive surveillance of this youngster rather than offer input on our suggestion that this …

Prevention of Teratogenic Antiserum-Induced Dysmorphology by Methionine Supplement in Rat Embryos Cultured in Vitro

Reproductive Risks of Ionizing Radiation: The Contribution of Animal Studies and New Clinical Studies in Resolving the Threshold Dose for Teratogenesis and the Risk of Cancer and Mental Retardation

Mechanisms of Nutritionally Caused Congenital Malformations: The Role of Methionine in Counteracting Antiserum-Induced Embryopathy • 362

NUTRITION STUDIES DURING EARLY ORGANOGENESIS: DISPARATE UTILIZATION OF LEUCINE AND METHIONINE BY THE 8.5 AND 9.5 DAY RAT EMBRYO. • 326

DESERT STORM SEQUELAE: ARE GULF WAR VETERANS FATHERING AN INCREASED INCIDENCE OF CHILDREN WITH CONGENITAL MALFORMATIONS?. 472

The examination of pregnant women using diagnostic ultrasound has increased greatly over past decades in the United States. As sonography techniques have been altered and refined, there has been renewed interest concerning possible effects on the developing fetus, since exposures in mid-gestation occur during the sensitive period of brain development. The present study is concerned with possible neonatal functional deficits due to exposure of the fetus to ultrasound. An ultrasound exposure tank was designed specifically for controlled studies of bioeffects. Thirty-six pregnant rats were anesthetized, immersed to the axilla in a water tank and exposed on the 15th, 17th and 19th days of gestation. Twelve rats were exposed to 5.0 MHz pulsed ultrasound of effective pulse duration equal to approximately 0.170 microseconds, pulse repetition rate 1 kHz, and a spatial peak, temporal peak intensity (ISPTP) of 500 W/cm2, representing a clinically relevant exposure level. The spatial peak, pulse average intensity (ISPPA), spatial peak temporal average intensity (ISPTA) and maximum intensity (Im) were determined to be 100 W/cm2, 24 mW/cm2 and 230 W/cm2, respectively. The maximum rarefaction pressure, pr, was measured as 12.5 x 10(5) Pa, and the total power was 2.5 mW. Twelve other rats were exposed to 1500 W/cm2, ISPTP (ISPPA, 350 W/cm2; ISPTA, 58 mW/cm2; Im, 600 W/cm2). Twelve additional rats were sham-exposed. Since the focal area was about 0.5 cm2, computer-controlled stepper motors moved the rats through the ultrasound field to assure uniform exposure of the abdominal/pelvic region. Total exposure time was 35 min. Additionally, a miniature thermocouple was implanted in a few rats to verify that no significant increase in body temperature took place during exposure. All neonates were subjected to five reflex tests and observed for four physiological parameters. Postnatal growth also was monitored. Analyses of the data indicate there were no significant alterations in neonatal development or postnatal growth due to exposure to 5.0 MHz ultrasound below an intensity (ISPTP) of 1500 W/cm2. Studies continue to be completed at higher exposure levels to determine the margin of safety, and the animals will continue to be monitored and evaluated through young adulthood to determine if there are long-term behavioral effects due to fetal exposure to ultrasound.

The embryotoxic effects of neutron radiation on rodent embryos are documented, but there is disagreement about the dose-response relationship and the impact of protracting the dose. Pregnant rats were exposed to total absorbed doses of 0.15 to 1.50 Gy 14.1 MeV neutrons on day 9.5 after conception, coincident with the most sensitive stage of embryonic development for the induction of major congenital malformations. In general terms, the incidence of embryotoxic effects increased with increasing total absorbed dose. However, the dose-response relationship differed depending on the parameter of embryotoxicity chosen, namely, intrauterine death, malformations or very low body weight. In a second study, embryos were exposed to a single embryotoxic absorbed dose (0.75 Gy) administered at a range of dose rates, from 0.10 to 0.50 Gy/h. The results offer no evidence that protraction of this selected dose significantly increased or decreased the incidence or pattern of embryotoxicity of the neutron exposure used in...

This manual was prepared by 12 representatives of major medical centers in the United States and reviewed by three faculty members from major universities and two administrators from similar institutions. It has 11 sections and comes in a small (five- by seven-inch), loose-leaf format. The introduction describes the riskmanagement department and discusses specific issues of confidentiality, records, early warning systems, communication, and the resources that are available to the physician. The next section, "Policy Resources," provides a list of administrative staff who could be helpful to the physician in answering questions about risk management or medicolegal situations that may arise. Within this section is also an excellent discussion of the patient's bill of rights and patient responsibilities. The next section deals with documentation and is an analytical approach to all aspects of record keeping with regard to medical care in a hospital. Besides discussing each of the various types of

Sir .—I read the editorial by Boyce 1 in the August 1990 issue of AJDC and believe it discusses a subject that should be of great interest to everyone. Dr Boyce is a thoughtful and kind individual who has given the reader his "highly personal" view on this subject. While personal views are sometimes insightful and creative, they may also fail to note that there may be extensive literature on the subject. Twenty-five years ago, I began what has evolved into an annual lecture to freshmen medical students at Jefferson Medical College, Philadelphia, Pa, entitled "Medicine, An Excuse From Living." 2 It was published in 1978 and reprinted in 1990. 3 Before and since the 1978 publication, many articles have been published dealing with this subject. The publications are not all in agreement and they do not reflect the same level of scholarship or insight. Dr Boyce discusses five criteria

Published data regarding the human teratogenic potential of 157 drug components that are frequently prescribed to outpatients in the United States were evaluated according to a protocol developed for TERIS, an automated clinical teratology resource. This protocol stipulates that a bibliographic search be performed on each agent, a brief narrative summary of the available teratologic information prepared, and a risk rating assigned. The ratings are determined by consensus of five clinical teratologists, who independently assess the magnitude of teratogenic risk associated with each agent under usual therapeutic conditions as "none," "minimal," "small," "moderate," "high," and "undetermined." Forty-nine percent of the components of these frequently prescribed drugs had insufficient published information available to assess the risk of human teratogenicity. Of the agents that could be rated, the teratogenic risk in usual therapeutic doses was considered to be minimal or less in 92.5%. Many of these agents have also been assigned Pregnancy Categories by the United States Food and Drug Administration (FDA) according to a system designed to provide therapeutic guidance. There was no more agreement than that expected by chance between TERIS ratings and the FDA Pregnancy Categories for 83 agents that were classified according to both systems. We believe that the FDA Pregnancy Categories should not be used to provide counseling regarding the risk of teratogenic effects to women who have taken medication during pregnancy. Such counseling should be based on a more comprehensive evaluation of the teratologic literature and clinical situation, but need not involve consideration of the therapeutic benefit of the agent.

We report that protease inhibitors can reduce the incidence of radiation-induced exencephaly in mice. Previous studies from this and other laboratories have demonstrated that protease inhibitors, in particular antipain and the Bowman-Birk inhibitor, are effective anticarcinogenic agents in a variety of in vivo systems and inhibit cell transformation in vitro. Given our results, further investigation is warranted into preventive effects of protease inhibitors on the inhibition of neural tube defects.

Forty-one pregnant Wistar strain rats were irradiated with 0.6-Gy X rays or were sham irradiated on the 9th or 17th days of gestation to determine if this dosage level would result in alterations in postnatal neurophysiologic development. Half of the mothers were sacrificed at term, and the developmental status of 221 newborns was evaluated. The remaining mothers delivered and raised their litters. The 161 offspring were observed for the age of attainment of the following physiologic parameters: pinna detachment, eye opening, testes opening. Offspring were also tested for the acquisition of the following selected reflexes: surface righting, negative geotaxis, auditory startle, air righting, and visual placing. Term fetal weight was lower than the controls in the group irradiated on the 9th day but was recuperable postnatally. None of the 9 developmental tests performed postnatally were abnormal in the animals irradiated on the 9th day. Thus, at least with regard to these measures, the surviving embryos exposed during the all-or-none period could not be differentiated from the controls. Offspring irradiated on the 17th day exhibited retarded growth which persisted during neonatal life. The three-day-mean neonatal weight was significantly lower in the group irradiated on the 17th day compared to controls. There were no significant maternal body weight or organ/weight differences between the groups. Rats exposed in utero on the 17th day had a significantly delayed acquisition of air righting. These results demonstrate that 0.6-Gy in utero irradiation on the 17th day of gestation can cause subtle alterations in growth and development of the Wistar strain rat during postnatal life.

The present investigation was designed to study the effects of protracted prenatal exposure of rats to a 20-mW/cm2 power density level of microwave radiation at a frequency of 2450 MHz. Preliminary studies using 24 rats indicated that this power density level did not cause a significant increase in maternal body temperature as measured by a rectal thermocouple. Of 75 pregnant rats, 12 were exposed to microwave radiation, 4 sham-irradiated, and 59 used as environmental control animals. Rats were exposed throughout pregnancy for a total exposure time of approximately 270 h. Daily maternal weights were recorded before irradiation. At term animals were killed, selected maternal tissues were removed, and fetal and placental positions and weights were recorded. After fixation for at least 3 wk, 462 term fetuses were dissected and examined for abnormalities. No significant alterations were observed for the following parameters: maternal weight gain during pregnancy, term maternal organ weights (brain, liver, kidneys, ovaries), term fetal weight, resorption rate, or abnormality rate. These results indicate that the protracted exposure of pregnant rats to 2450-MHz microwave radiation at a power density level of 20 mW/cm2 is not embryopathic.

The basement membrane (Reichert's membrane) of the entire capsular portion of the parietal yolk sac of rat embryos was examined both morphologically and chemically at various stages of gestation. The overall microscopic and compositional analyses showed Reichert's membrane to be typical of basement membranes isolated from other tissues and species. However, with increasing gestational age (from 11.5 to 17.5 days) a number of changes involving Reichert's membrane were noted: 1. The thickness increased rapidly then declined, while the surface area increased tenfold; 2. The total protein content increased twenty-fold while the collagen content increased eight-fold. As a result, the relative collagen content declined significantly; 3. The changes in the amino acid and carbohydrate composition were consistent with the latter finding. The observations listed above were evaluated in light of their possible relevance to an understanding of the morphogenesis of basement membranes during development, and to the possible mechanisms involved in pathogenesis of basement membrane dysfunction.

Thirty-nine pregnant adult Wistar strain rats were randomly assigned to one of three exposure groups: 0, 0.75, or 1.50 Gy X-radiation total exposure. Animals were exposed from the 14th to the 18th days of gestation at 0, 0.15, or 0.30 Gy per day. At term, 15 rats were killed and morphologic analyses were completed. Twenty-four rats were allowed to deliver their offspring. On the first day of postnatal life, litters were reduced to a maximum of eight pups per litter, with equal numbers of male and female offspring wherever possible. A total of 187 pups were observed for the age of acquisition of five reflexes (air righting, surface righting, visual placing, negative geotaxis, auditory startle) and the appearance of four physiologic markers (pinna detachment, eye opening, vaginal opening, testes descent). There was significant dose-related weight reduction in term fetuses and offspring throughout the 86-day postnatal period. Postnatal growth rate (g gained/day) was unaffected. Adult offspring brain and gonadal weight and organ weight:body weight ratios were reduced. Using the PAC50 methodology, dose-related alterations occurred in the acquisition of several reflexes. All physiologic markers exhibited a dose-related delay in appearance. These results indicate that fractionated exposure to X-radiation during the fetal period in the rat results in dose-dependent alterations in postnatal growth and physiologic development. These studies are important for our understanding of the long-range effects of prenatal exposure to ionizing radiation late in gestation.

In 1967, I indicated that the number of lawsuits involving malformed infants seemed to be increasing, not realizing that the increase was foretelling an epidemic. The reasons for this epidemic are described in this paper and are due to attitudes and happenings in the medical, legal, and lay sectors of our society. Case histories have been used to demonstrate that the litigation process can produce pain and suffering. The case histories also indicate that, when the members of family become orchestrated by a lawyer into the position of devoting a great deal of their energy to litigation, many high priority family responsibilities are ignored and important ethical standards are distorted. To win at all costs may be good for a football team, but it is obviously bad for a family. We must take drastic changes in the method of supporting the victims of disease and injury so that litigation is no longer necessary to compensate and support patients and families, whether negligence is or is not a factor. Recommendations for diminishing the malpractice crises include: education of the patient about the consequences of the litigation process--that only a small portion of the malpractice premium dollar ever reaches the patient and that most human malformations are not produced by medical negligence, altering the deteriorating image of the physician, reversing the increase in irresponsible medical expert testimony and changing the laws pertaining to medical licensure and loss of medical licensure, improving the health care system, making the awards more realistic by taking into consideration community and insurance resources of the patient and by eliminating lump sum awards and "punitive" awards, decreasing lawyer representation in legislative bodies so that legal reforms will become a possibility, and eliminating the contingency fee system by replacing it either with legal insurance so that the attorney is working for the patient or by adopting no-fault malpractice insurance with binding arbitration so that the negligently injured patient is compensated properly. The process of litigation rarely solves the patient's problems and frequently develops into a disease all its own.

Significant �, 3$3-hydroxysteroid dehydrogenase (3�-HSD) activity was observed in homogenates of rat parietal yolk sac (PYS) incubated with [3 HI -labeled pregnenolone or dehydroepiandrosterone in the presence of NAD+. The enzyme(s) is localized exclusively in the trophoblastic giant cells which constitute the maternal surface of the PYS. The specific activity of 3j3-HSD in PYS is maximal on Day 13 of pregnancy and then drops precipitously. Total 3�-HSD activity of PYS on Days 13 and 14 is comparable to that of the chorioallantoic placenta on the days of its maximal activity (Days 15-19 of pregnancy). The potential for the production of significant amounts of progesterone by the PYS suggests that this extraembryonic membrane is a true steroid hormone producing organ. Furthermore, since a progesterone primed uterus is required for the maintenance of pregnancy, the presence of 3�l-HSD activity in the PYS indicates a role for proges

The deafening effect of high intensity noise is well known—from rock music, aircraft, snowmobiles, motorcycles and the shooting of guns. The effects of hospital noise and its interaction with ototoxic drugs are less well known. The subject is of particular importance to pediatricians, because infants in incubators are exposed to substantial noise from the motor, airflow, respirators, slamming of incubator doors and the baby's own crying. Furthermore, animal experimentation1 shows that the ototoxic drug, kanamycin (often given to the premature infant to combat sepsis), can potentiate the effect of noise on hearing loss as much as 100-fold. Whether or not an interaction between noise and potentially ototoxic drugs occurs in man is as yet unknown. MEASUREMENT Noise has frequency and intensity. Frequency is measured in cycles per second, designated hertz (Hz). The young human ear is sensitive to a frequency range of 20 to 20,000 Hz. White noise, the auditory counterpart of white light, has equal energy in each frequency in the audible range. Intensity is measured in decibels on a scale which is linear with respect to audible frequencies. This measurement is designated dB (linear). Since the human ear is more sensitive to the damaging effects of high frequency sound than to low frequency, a better correlate with noise-induced hearing loss can be obtained when low frequencies are filtered out. Filtered sound level, measured on a so-called A-weighted scale, is designated dB(A). Room conversation produces 60 to 70 dB(A), rock music 100 to 120 dB(A) and snowmobiles 105 to 135 dB(A) for the driver.

It is evident that significant permanent tissue hypoplasia can be produced following radiation exposure late in fetal development. Because two organs, brain and testes, are developmentally and functionally interrelated, it was of interest to determine whether fetal testicular hypoplasia was a primary or a secondary effect of fetal brain irradiation. Twenty-four pregnant Wistar strain rats were randomly assigned to one of four groups, and a laparotomy was performed on day 18 of gestation. The fetuses received sham irradiation, whole body irradiation, or only head/thorax or pelvic body irradiation at a dosage level of 1.5 Gy. Mothers were allowed to deliver and raise their offspring until postnatal day 30, when the offspring were weaned. At 60 days of age, 74 male offspring were allowed to mate with colony control females of similar age until successful insemination or until the males reached 90 days of age, when they were killed. Testes were weighed and processed for histologic examination. Direct radiation of testes, due to whole body or pelvic exposure, resulted in testicular growth retardation and significantly reduced spermatogenesis. Breeding activity of the males and the percent of positive inseminations were also slightly reduced. However, a significant percentage of male offspring receiving direct testicular radiation did produce offspring. Head/thorax-only irradiation did not adversely affect testicular growth or spermatogenesis. Therefore, the use of histologic analysis as the sole determinant of infertility may be misleading. This study indicates that testicular growth retardation and an increased infertility rate result from direct prenatal exposure of rat testes to X-radiation and are not necessarily mediated via X-irradiation effects on the central nervous system.

Rabbit anti-rat Reichert's membrane (RM) serum, when injected into pregnant rats on the ninth day of gestation, produced embryolethality and stunting but a surprisingly low incidence of malformations. Immunofluorescent studies revealed that the maternally injected RM antiserum localizes in RM and in the basement membrane of some maternal kidney tubules but not in the maternal glomerulus or in the cytoplasm of the visceral yolk sac (VYS) cells as had teratogenic VYS and kidney antisera. When antiserum against rat RM was injected into mice, localization occurred in the glomerular basement membranes, thus confirming the findings of Pierce and co-workers. When teratogenic term VYS antiserum is adsorbed with RM, it still localizes in the VYS, does not localize in RM, and is still teratogenic. When this same antiserum is adsorbed with VYS, the antiserum is no longer teratogenic. It appears that the localization of antibodies in the VYS cells is the major contributor to the production of congenital malformations because localization of antisera in RM alone was associated with a very low incidence of teratogenesis. Since both structures participate in a multitude of biochemical processes, which include adsorption, transport, catabolism, and anabolism of nutrients, nonnutrients, and waste products, there are many plausible hypotheses to explain the nature of the parietal and visceral yolk sac dysfunction.

The objective of this investigation was to determine the effect of low-dose prenatal X-irradiation on postnatal growth and neurobehavioral development, and whether alterations would manifest at dosages lower than those which produce anatomic malformations from exposure at the most sensitive period of organogenesis. Ninety-eight Wistar strain rats were exposed to 0.1, 0.2, or 0.4 Gy X-radiation of were sham irradiated on the 9th or 17th day of gestation. A conventional teratologic evaluation was completed on half of the animals (572 fetuses). The age of appearance of four physiologic markers and of acquisition of six reflexes was observed in 372 offspring. Exposure during early organogenesis at these levels had no effect on any of these parameters. Prenatal exposure to X-radiation on the 17th day of gestation at dosage levels greater than 0.1 Gy resulted in alterations in the appearance of three postnatal neurophysiologic parameters. Growth retardation throughout the postpartum period also was observed in the offspring. The induction of developmental and reflex alterations had a comparable threshold to the known threshold for anatomic malformations on the 9th day. These results indicate that all of the parameters studied had thresholds either at or above 0.2 Gy acute radiation, and that the postpartummore » developmental and reflex acquisition measures were not more sensitive indicators of exposure to X-radiation than growth parameters.« less

Basic principles of teratology and mechanisms of teratogenesis applicable to human exposures to environmental drags and chemicals are discussed. The available clinical and experimental animal literature on environmental agents alleged or known to cause human malformations Is critically reviewed and summarized.

Since it has been well established that heterologous antiserum against whole rat kidney is both teratogenic and nephrotoxic, it is important to determine if these two separate pathologic effects are caused by the same or a different group of antibodies. Two antisera were prepared from the following groups of soluble antigens: (1) GBM antigens were obtained by solubilizing isolated rat glomerular basement membrane with trypsin, (2) PBS-soluble kidney antigens were obtained from the supernatant of homogenized, perfused whole rat kidneys following centrifugation at 105,000 × G. Both antisera were assayed for teratogenicity and nephrotoxicity. Nephrotoxicity of the antisera was evaluated by measuring proteinuria and examining light and electron microscopic preparations of kidneys following the injection of antisera into male rats and pregnant rats. The antiserum to trypsin-solubilized GBM antigens was nephrotoxic but not teratogenic while the antiserum to PBS-soluble kidney antigens was teratogenic but not nephrotoxic. In addition, the results of absorption studies utilizing antiserum against whole rat kidney indicate that a) the teratogenic effect of the antiserum against whole rat kidney can be abolished by incubating the antiserum with PBS-soluble kidney antigens, b) the nephrotoxic effects of the antiserum against whole rat kidney still persists after absorbing the antiserum with PBS-soluble kidney antigens. In vivo immunofluorescent studies demonstrated that the antibodies to PBS-soluble kidney antigens localized in the maternal GBM, Reichert's membrane, and visceral yolk sac endodermal cells whereas the antibodies to trypsin-solubilized GBM antigens localized only in the maternal GBM. These data indicate that the teratogenic antibodies present in the classical (Masugi) nephrotoxic serum are not the same group of antibodies that are responsible for nephrotoxicity.

The teratogenicity of rabbit anti-rat visceral yolk-sac antiserum, injected into pregnant rats at either 8 ·5 or 9 ·5 days of gestation, has been confirmed. Normal rabbit serum was found not to be teratogenic. When conceptuses from 9 ·5-day pregnant rats were cultured for 48 h in heat-denatured homologous serum, to which antiserum was added for the final (or the penultimate) 6 h of culture, embryonic development was normal. The protein contents of embryos and yolk sacs (at harvesting) were however decreased. When antiserum was present in cultures for the final 6 h, pinocytosis by the yolk sac, as measured by the uptake of 125l-labelled polyvinylpyrrolidone (PVP), was decreased to an extent related to the concentration of antiserum in the culture medium and to a minimum level of about 40%. The presence of antiserum in cultures for the penultimate 6 h only, with 125I-labelled PVP present for the final 6 h only, produced an identical result. No uptake of radioactivity into the embryo was observed, in either the absence or presence of antiserum. When conceptuses were cultured for the final 6 h in vitamin- and glucose-supplemented dialysed homologous serum whose proteins were [3H]leucine-labelled, the presence of antiserum for either the final or penultimate 6 h again resulted in a decrease in the uptake of radioactivity by conceptuses. Uptake of radioactivity into yolk sac and embryo was decreased by the same amount, indicating that proteolysis in yolk-sac lysosomes was not inhibited. In parallel control experiments in which normal rabbit serum replaced rabbit anti-rat visceral yolk-sac antiserum, no effects on embryonic development, on protein contents of yolk sacs and embryos at harvesting, or on the uptake of radioactivity by conceptuses were observed. These results are interpreted as providing evidence that teratogenic antibodies decrease pinocytosis of protein by visceral yolk sac at the early organogenesis stage and consequentially decrease the availability of amino acids and thus protein synthesis in both yolk sac and embryo. It is proposed that this effect constitutes the mechanism of action of teratogenic antisera.

The criteria used to regulate exposure to a drug or chemical are different from those employed to implicate an agent as a human teratogen In general and in an individual patient. The importance of regulating exposures and in implicating teratogenicity merit special attention to the problems of educating physicians and the lay public, scientifically evaluating teratogenicity, preventing unnecessary abortions, and protecting the public.

It has been well established that heterologous antisera against whole rat kidney homogenate when injected into pregnant rats during the embryonic organogenetic period may induce abnormal embryonic development. Attempts were made to isolate the active components from soluble rat kidney extract by ammonium sulfate precipitation, anion-exchange chromatography, and concanavalin A-Sepharose 4B affinity chromatography. The glycoproteins isolated were capable of stimulating the production of potent rabbit antisera. When injected ip into the 9th day pregnant rats, these antisera induced embryonic death, congenital abnormalities, and fetal growth retardation. Eighty-four surviving fetuses were examined, all of them were malformed. The most frequently observed congenital defects were anophthalmia and microphthalmia. Attempts were made to analyze the glycoprotein fraction by discontinuous and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The results indicate that the glycoproteins were of high molecular weight and could be dissociated by SDS into a multitude of molecules or subunits. Although double immunodiffusion indicated that there were one major and two minor antigens in the glycoprotein fraction, attempts to identify the antigens as to their size by analytical gel electrophoresis have not been successful. Electron microscopic study seemed to suggest that the glycoproteins might tend to aggregate to form particulates. The underlying mechanism whereby the antisera to these glycoproteins induce abnormal embryonic development is not understood. The hypotheses to explain the possible sites of teratogenic antibody interaction are discussed.

This review discusses the mechanisms involved in congenital malformations that are primarily environmentally produced. The etiology of human malformations in the 1st year of life is genetic in 20-25% of cases environmental in 9-10% of cases and unknown (polygenic or multifactorial) in the remaining instances. Environmentally produced malformations demonstrate stage sensitivity a dose-response relationship threshold effects and genetic variability. It has been suggested that mechanisms of teratogenesis include mutation chromosomal aberrations mitotic interference altered nucleic acid synthesis and function lack of precursors and substrates for biosynthesis altered energy sources enzyme inhibition osmolar imbalance altered membrane characteristics and other mechanisms. However the fact that an environmental agent can induce 1 of these pathologic processes does not guarantee that exposure will result in teratogenesis nor does it enable prediction of teratogensis in a human if an agent exhibits 1 of these characteristics in an experimental test system. Agents that have been proven to cause congenital malformations in humans include alcohol aminopterin and methotrexate androgens coumarin derivatives diethylstilbestrol diphenylhydantoin methylmercury oxazolidine-24-diones polychlorinated biphenyls progestins radiation tetracycline thalidomide and drugs used to treat maternal hyperthyroidism. Continued investigation of the etiology and mechanisms of teratogenesis is needed to prevent exposure to environmental teratogens.

Many forces have created the epidemic of negligence and malpractice litigation. One of the contributing factors to the rising rate of nonmeritorious litigation is the increasing number of unqualified and irresponsible expert witnesses. The high remuneration has attracted physican-scientists who are unaware of the proper role of an expert witness. They are frequently manipulated by the attorneys and function as partisans rather than scholars. The role of the expert witness should be taught in medical and graduate school. Testimony should be treated as a scholarly endeavor and experts should be encouraged to seek peer review of their opinions and not to testify secretly and in isolation. It is suggested that greater visibility of experts and their testimony (light of day phenomenon) should raise the quality of expert witness testimony and encourage more qualified experts to participate as expert witnesses, thus removing the stigmata usually associated with unqualified expert witnesses.

Summary The parietal yolk sac (PYS) of the rat fetus at the 14th day of gestation contains glucocorticoid as well as progesterone receptors; both are present in the trophoblast cell layer. Following heat activation the receptors are capable of binding to deoxyribonucleic acid-(DNA-)cellulose. Glucocorticoid receptors, but not progesterone receptors, are also present in the visceral yolk sac (VYS) at the 14th day of gestation. Greater amounts (some 250 femtomoles/mg cytosol protein) of a glucocorticoid receptor are present in the VYS on the 17th day of gestation. The Kd is approximately 4×10−9 m ; following activation it also binds to DNA—cellulose. The elution pattern of the activated VYS receptor from diethylaminoethyl-(DEAE-)Sephadex, however, is similar to that found with kidney and colon rather than that of liver (i.e., it resembles corticosteroid binder IB rather than binder II) indicating a possible role in transport. Although the receptors are separate entities, progesterone competes as effectively as corticosterone for binding to the glucocorticoid receptors in both the PYS and VYS, thus raising the question of the possible effect of changes in progesterone concentrations on the functioning of glucocorticoids during development.

Although major advances have been made in -the epidemiology of birth defect surveillance, in intrauterine diagnosis and treatment, and In clarifying the role of environ-mental factors, we are uncertain about the causes of the majority of birth defects. Miseducation of the public and some professional groups has led to an overemphasis on the importance of drugs and chemicals as causes of birth defects and has resulted in major health and social problems. Many problems remain in preventing or reducing the Incidence of human malformations, which may be solved by the combined efforts of clinical surveillance programs and advances in the fields of genetics, developmental biology, and biochemistry.

This investigation was carried out to determine whether heterologous antisera to alpha fetoprotein (AFP) are embryotoxic to developing rat embryos. Homogeneous rat AFP was isolated and antisera directed against this glycoprotein were produced in rabbits, horse and goat. The effect of the antisera on embryonic development was examined by injecting the antisera intraperitoneally into pregnant rats on the ninth, eleventh and thirteenth days of gestation. The results demonstrated that there was no evidence of increased incidence of fetal abnormalities in 472 surviving fetuses of 42 injected rats. There was no evidence of increase embryonic death or retardation of intrauterine growth following administration of the antisera on the ninth, eleventh and thirteenth days of gestation. The localization of the injected antisera was examined by the indirect immunofluorescent method. The results showed that the heterologous AFP antibodies localized specifically in the visceral yolk sac placenta. No antibody localization was observed in the embryo proper or the chorioallantoic placenta. It is speculated that the localization of AFP antibodies in the visceral yolk sac does not interfere with the embryotrophic function of the visceral yolk sac placenta.