bluuebunny/crossref_metadata_2025 huggingface dataset:
Reporting of malformations in routine health registers
Authors: Hemminki Elina , Meriläinen Jouni , Teperi Juha
Published: June 2005

The utility of three national registers—the malformation, birth, and hospital in‐patient discharge registers—in identification of malformations among 60,255 children born in 1987 in Finland was compared. Information in the malformation register is collected by specific reporting of physicians; information on the malformed children in the other two registers in 1987, through 1990 was routinely collected and identified by ICD 9‐codes (740‐759, 7886A). From October 1990 on, the ICD‐9 codes were omitted from the birth register and malformation data were asked only in a yes‐no question. In 1987, the malformation register included 1,032, the birth register 3,084 and the inpatient register 2,003 malformed infants identified up to the age of 1 year. There was underrepresentation of almost all malformation diagnoses in the malformation register. Individual linkage of the three registers showed that the malformation register revealed very few cases not recorded in the birth and the in‐patient registers. With the adoption of the new recording method in the birth register beginning in October 1990, reports of malformation declined by 75%. Our analyses showed that data sources based on diagnoses collected routinely and not requiring an explicit decision on whether or not a problem is a malformation, can be more useful for routine surveillance of occurrence of malformations. © 1993 Wiley‐Liss, Inc.
Evaluation of the effectiveness of a teratogen information service: A survey of patient and professional satisfaction
Authors: Ludowese C. J. , Marini T. , Laxova R. , Pauli R. M.
Published: June 2005

We have evaluated the effectiveness of the Wisconsin Teratogen Project (WTP), a teratogen information service, using two retrospective surveys. We surveyed medical professionals who utilized the WTP and patients who had received teratogen counseling in a clinic setting. The results from the medical professional survey indicated that medical professionals rely on the WTP for accurate and convenient teratogen information. A tendency to rely on the Physician's Desk Reference as an alternative resource was noted, reinforcing the need to encourage professionals to use teratogen information service projects. Major findings and conclusions from the patient survey included: patients found counseling to be most helpful if, whenever possible, numeric risks were provided; recommendations made in the absence of known risk were not considered by patients to be helpful for providing reassurance; overall compliance with recommendations was high but behavioral recommendations seemed to reduce reassurance and increase dissatisfaction with the service for some patients; and pregnant women exposed to low‐dose ionizing radiation were more likely to have considered termination of pregnancy prior to referral but were not more likely to terminate following counseling.

Our findings suggest that although the WTP is considered an effective service overall, teratogen counselors should give special consideration to patient and counseling characteristics as these can significantly influence the perception of the risk counseling provided. Particular attention should be given to patients with low‐dose ionizing radiation exposure, since misperception of its teratogenic risk is extremely common. © 1993 Wiley‐Liss, Inc.
Relationship between abnormal somite development and axial skeletal defects in rats following heat exposure
Authors: Cuff Joyce M. , Kimmel Gary L. , Kimmel Carole A. , Heredia Dinorah J. , Tudor Natalie , Chen Judy
Published: June 2005

The effects of in vivo heat exposure on gestation day (GD) 10 rat embryos were evaluated on GD 11 to determine the relationships between morphological sequelae following in vivo and in vitro exposures and between effects detected on GD 11 and those observed in postnatal day (PND) 3 pups. Anesthetized rats were exposed to 42°C in a warm air incubator until their rectal temperatures reached 41°C or until a rectal temperature of 42–42.5°C had been maintained for 5 minutes. Heat‐exposed embryos exhibited a significant decrease in growth parameters including head length, somite number, and protein content/embryo versus controls. These changes correlated well with in vitro effects from an earlier study (G.L. Kimmel et al., '93). Among the morphological endpoints which were slightly delayed in development were the caudal neural tube, branchial bars, forelimb and hindlimb. The only effect on the embryos that could not be explained as a transient delay in development induced by heat was the induction of unsegmented somites. Additional embryos were exposed to 42°C for 15–20 min in vitro and examined specifically for unsegmented somites, which were observed in 47% of embryos exposed to 42°C in vivo or in vitro. This phenomenon was observed in somites 9–20, i.e., those that give rise to cervical and thoracic vertebrae and ribs. These results correlated well with the axial skeletal malformations observed in PND 3 pups exposed to the same heat treatment (C.A. Kimmel et al., '93). © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Glucose and scyllo‐inositol impair phosphoinositide hydrolysis in the 10.5‐day cultured rat conceptus: A role in dysmorphogenesis?
Authors: Strieleman P. J. , Metzger B. E.
Published: June 2005

Culture of the postimplantation rat conceptus from gestational day 9.5–10.5 in media supplemented with d‐glucose or scyllo‐inositol decreases tissue myo‐inositol and phosphoinositides with a concomitant increase in dysmorphogenesis. A number of mitogenic agents initiate cellular proliferation and differentiation through receptors coupled to phosphoinositide hydrolysis. To test whether the decrease in conceptus phosphoinositides is associated with a reduced phosphoinositide hydrolytic response, we developed a protocol to stimulate phosphoinositide hydrolysis. Phosphoinositide hydrolysis was monitored by measurement of [3H]inositol phosphates after preincubation in serum free media. We examined the ability of serum, platelet‐derived growth factor (PDGF), epidermal‐derived growth factor (EGF), insulin‐like growth factor 1 (IGF‐1), insulin like growth factor 2 (IGF‐2), endothelin‐1 (ET‐1), and endothelin‐2 (ET‐2), to stimulate phosphoinositide hydrolysis. As measured by [3H]inositol monophosphate ([3H]InsP1) accumulation, normal rat serum, ET‐1, and ET‐2 stimulated phosphoinositide hydrolysis 47%, 420%, and 154% above the basal rate observed in serum free controls. EGF stimulated a statistically insignificant 15% increase while PDGF, IGF‐1, or IGF‐2 were without effect. We further characterized ET‐1 stimulated phosphoinositide hydrolysis. Dose‐response studies disclosed that incremental increases in [3H]InsP1 (129–420%) are observed over a concentration range of 10–1,000 nM. Maximal stimulation was not reached even at 1,000 nM. Temporally [3H]InsP1 and [3H]InsP3 levels increased linearly during incubation periods of 15‐60 min. We further analyzed ET‐1 stimulated phosphoinositide hydrolysis in 10.5‐day conceptuses cultured for 24 hr in media containing high concentrations of glucose (23.3‐56.6 mM) or scyllo‐inositol (0.55, 5.5 mM). Under these dysmorphogenic conditions that concomitantly decrease the phosphoinositide precursor pool the response to ET‐1 was blunted 28–76% for glucose and 29–65% for scyllo‐inositol. This suggests that the effect of glucose and scyllo‐inositol on lowering phosphoinositide precursor pools also results in a decrease in the response to agonists using the inositol/lipid intracellular pathway. This impaired signaling response may contribute to initiating dysmorphogenic events in diabetic embryopathy. © 1993 Wiley‐Liss, Inc.
Developmental changes in the optic nerve related to ethanol consumption in pregnant rats: Analysis of the ethanol‐exposed optic nerve
Authors: Pinazo‐Duran Maria Dolores , Renau‐Piqueras Jaime , Guerri Consuelo
Published: June 2005

Visual impairment is one of the most common ophthalmic abnormalities in fetal alcohol syndrome. Pathologic changes in optic nerve development related to alcohol consumption could be involved in this dysfunction. In order to assess the consequences of pre‐ and postnatal exposure to alcohol on the developing optic nerve, we administered an ethanol‐containing liquid diet (5% w/v) before and during gestation and throughout lactation to rats and their offspring. A group of control animals were kept on a pair‐fed isocaloric diet. The optic nerves were obtained at key stages from fetuses (21 days of gestation) and pups (4, 7, 14, 21 and 28 postnatal days). Samples of the optic nerve cross‐section, behind the eyeball, were processed for analysis of gliogenesis, myelinogenesis, axonal growth, and remodelling events, using light and electron microscopy. Qualitative, morphometric, and immunocytochemical analyses, alternatively using anti‐GFAP and anti‐MBP antibodies, were carried out. Optic nerve cross‐sections from prenatal and postnatal alcohol‐exposed rats showed a decrease in size. Ultrastructural alterations and retarded development in macroglial cells, optic axons, and myelin sheath were also observed. The most prominent abnormalities were: damage of cytoplasmic organelles and disorganization of cytoskeleton in astrocytes; a decrease in free ribosome density and nuclear membrane inclusions in oligodendrocytes; and fragmentation of lamellae, aberrant myelin sheaths and intralamellar inclusions in myelin. These findings suggest that alcohol abuse during pregnancy is teratogenic to the optic nerve and closely related to the altered visual function. © 1993 Wiley‐Liss, Inc.
Effects of developmental stage and tissue type on embryo/fetal DNA distributions and 5‐fluorouracil‐induced cell–cycle perturbations
Authors: Elstein Kenneth H. , Zucker Robert M. , Andrews James E. , Ebron‐McCoy Marian , Shuey Dana L. , Rogers John M.
Published: June 2005

Cell‐cycle analysis of nuclei obtained from the circulating erythroblasts (gestational day [GD] 11–16), livers (GD 14–19), and whole embryos (GD 10–13) or remaining (extrahepatic) tissues (GD 14–16) of rat embryos/fetuses revealed age‐ and tissue‐dependent variations in the relative percentages of cells in the G0/G1, S, and G2/M phases of the cell cycle. With development, the rate of cell proliferation declined resulting in decreases in the relative percentage of S‐phase cells and increases in the G0/G1 percentage, while the percentage of G2/M‐phase cells remained relatively constant. Comparing tissue cell‐cycle profiles during development, erythroblasts exhibited the most rapid age‐dependent decline in S‐phase percentage (from 75% at GD 11 to 8% by GD 14), embryos/extrahepatic tissues exhibited a more gradual reduction (from 55% at GD 10 to 14% by GD 15), while the hepatic isolates exhibited a relatively constant S‐phase percentage of approximately 40% from GD 14 to GD 18 before decreasing to 23% at GD 19. These age‐dependent variations suggest that cellcycle distribution may be useful in staging embryogenesis and in detecting abnormal development.

To determine how these developmental and organ‐specific cell‐cycle variations affect toxic response, we sampled GD 11–13 embryos 6 hr after maternal administration of a teratogenic dose of 5‐fluorouracil (5‐FU), a thymidylate synthetase inhibitor that induces S‐phase accumulation. The results indicate that, on a relative basis, the amount of induced S‐phase accumulation in erythroblasts and whole embryos 6 hr postdosing increased with development. In contrast, a time course of hepatic cell‐cycle distributions from GD 14 embryos after maternal dosing revealed that S‐phase accumulations occurred at an earlier time, possibly as a consequence of a higher proliferative rate. These findings suggest that the extent of observed toxicant‐induced cell‐cycle perturbations depends on gestational age, tissue type, and the time of sampling. © 1993 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Developmental toxicity of gemcitabine, an antimetabolite oncolytic, administered during gestation to CD‐1 mice
Authors: Eudaly J. A. , Tizzano J. P. , Higdon G. L. , Todd G. C.
Published: June 2005

Gemcitabine was given intravenously to female mice on gestation days (GD) 6–15 at doses of 0, 0.05, 0.25, or 1.5 mg/kg/day (0, 0.15, 0.75, or 4.5 mg/m2/day, respectively). Animals assigned to the teratology segment (25/group) were killed on GD 18 for examination of maternal hematologic parameters and organ weights, as well as fetal viability, weights, and morphology. The postnatal segment females (20/group) were allowed to deliver, and offspring physical, behavioral, and reproductive parameters were monitored. After offspring weaning, these dams were killed for hematologic and organ weight evaluations. At necropsy, 3 days after the final dose, the teratology segment dams showed dose‐related increases in spleen and thymus weights. These changes were accompanied by a dose‐related decrease in leukocytes and modest increases in mean corpuscular volume (MCV) and hemoglobin (MCH) at the two higher doses. On postpartum day (PPD) 21, the dams in the postnatal segment showed no treatment‐related effects on these organ weights or hematologic parameters, indicating recovery of these maternal parameters within 3.5 weeks following termination of treatment. The decreases in maternal body weight and food consumption observed during gestation, and in liver and uterine weights at term in the 1.5 mg/kg/day group, were considered to be secondary to a high rate of prenatal mortality, evidenced by increased resorptions in the teratology segment and decreased live litter size in both segments of the study. Additional indications of developmental toxicity in this dose group were an increased incidence of malformations, primarily cleft palate, decreased fetal weights in the teratology segment, and decreased neonatal survival in the postnatal segment. Other indications of offspring toxicity were decreased startle amplitude in the 0.05 and 1.5 mg/kg/day treatment‐derived males, and decreased ovarian weights in all F1 females compared to controls. However, offspring growth, appearance of physical landmarks, F1 activity levels, active and passive avoidance, and reproductive performance were not affected adversely in the surviving offspring of the 1.5 mg/kg/day treatment‐derived group or in mice from either of the two lower dose groups. These results indicate that maternal effects related to the antiproliferative actions of gemcitabine may be detected at doses below those which result in overt developmental toxicity, i.e., malformations, weight changes, and decreased prenatal and neonatal survival. © 1993 Wiley‐Liss, Inc.
Clinical teratology counseling and consultation case report: Two distinct anterior neural tube defects in a human fetus: Evidence for an intermittent pattern of neural tube closure
Authors: Busam Klaus J. , Roberts Drucilla J. , Golden Jeffrey A.
Published: June 2005

Human neural tube closure is believed to be a continuous process that begins in the cervical region and progresses both rostrally and caudally. In contrast, an intermittent pattern of anterior neural tube closure has been demonstrated in rodents. Based on individual case photographs, a similar pattern of anterior neural tube closure, with multiple sites of closure, may also exist in humans. We report a human fetus with two distinct anterior neural tube defects separated by a cutaneous and mesenchymal bridge. The two defects occurred within distinct closure sites predicted by the murine model, one falling within closure II and the second within closure IV. Although one defect had adherent amniotic bands, evidence is presented to support a primary dysraphy rather than disruption from an amniotic band. This case provides further evidence supporting an intermittent pattern of anterior neural tube closure in human embryogenesis. © 1993 Wiley‐Liss, In.
Histological study of the cranial neural folds of mice genetically liable to exencephaly
Authors: Gunn T. M. , Juriloff D. M. , Vogl W. , Harris M. J. , Miller J. E.
Published: June 2005

The SELH/Bc (SELH) inbred stock of mice has a high liability to the neural tube closure defect, exencephaly. All SELH embryos close their cranial neural tubes by an abnormal mechanism, lacking elevation and initiation of fusion in the posterior prosencephalon/anterior mesencephalon region. Most embryos complete closure of the cranial neural tube by extension of a more rostral site of fusion, but in 10–20% this process fails, and the embryos are subsequently exencephalic.

In this study, transverse histological sections of the cranial neural folds of SELH embryos at the 3–5, 6–8, and 9–11 somite stages were compared to those of two strains with normal neural tube closure, ICR/Bc and LM/Bc. At all stages, consistent morphological differences were observed between SELH and the two normal strains. In 3–5 somite SELH embryos, the divergence of the folds from the neural groove is more angular, the folds are flatter, and their lateral tips appear “hooked” downward. In 6–8 somite SELH embryos, the lateral tips of the folds appear more elongated and in the prosencephalon they are less elevated than in the normal strains. The boundary between neuroepithelium and mesenchyme or surface ectoderm tends to be less clear than normal in SELH lateral tips. In 9–11 somite SELH embryos, divergence of the folds from the neural groove continues to be angular and the lateral folds are splayed horizontally. In addition, the lateral surface ectoderm is abnormally indented and the neuroepithelium/surface ectoderm boundary is more ventral and lateral in SELH than in ICR/Bc and LM/Bc.

The hypothesis that the defect in SELH cranial neural folds might involve the cytoskeleton was tested using a fluorescent probe for filamentous actin in 7 somite SELH and ICR/Bc embryos. The actin staining pattern in SELH embryos was like that of normal ICR/Bc embryos, with a strongly staining apical concentration in the neuroepithelium. This suggests that there is no gross cytological abnormality within the neuroepithelium, but does not rule out more subtle defects, such as those involving cytoskeletal function. © 1993 Wiley‐Liss, Inc.
Induction of a heat shock response (HSP 72) in rat embryos exposed to selected chemical teratogens
Authors: Mirkes Philip E. , Doggett Barbara , Cornel Leanne
Published: June 2005

A monoclonal antibody to the 72 kD heat shock protein (HSP 72), Western blot analysis and 2‐D gel electrophoresis/autoradiography were used to determine whether selected chemical teratogens induced the synthesis and accumulation of HSP 72 in postimplantation rat embryos exposed in vitro. The chemical teratogens studied include N‐Acetoxy‐2‐acetylaminofluorene (N‐Ac‐AAF), cadmium chloride (CAD), cyclophosphamide (CP), sodium arsenite (AS), and sodium salicylate (SAL). Exposures to test chemicals were selected that produced obvious embryotoxicity characterized by abnormal development and growth retardation. Of the five chemical teratogens studied, AS and SAL induced the synthesis and accumulation of HSP 72 in day 10 rat embryos. The kinetics of HSP 72 accumulation, however, differed between AS‐ and SAL‐treated embryos. Maximal levels of HSP 72 were observed 24 hours after AS exposure and 10 hours after SAL exposure. N‐Ac‐AAF, CD, and CP induced obvious embryotoxicity; however, none of these chemical teratogens induced HSP 72 at any of the timepoints assayed. Although only a small sample of chemical teratogens was studied, our results suggest that the heat shock response, characterized by the synthesis and accumulation of HSP 72, is not a general biomarker for chemical teratogens. © 1994 Wiley‐Liss, Inc.
Teratologic evaluation of rats prenatally exposed to pulsed‐wave ultrasound
Authors: Fisher J. Edward , Acuff‐Smith Karen D. , Schilling Mary A. , Vorhees Charles V. , Meyer Richard A. , Smith Nadine B. , O'Brien William D.
Published: June 2005

While there are no known risks associated with diagnostic ultrasound, uncertainty about the safety of prenatal ultrasound exposure remains. The purpose of the present experiment was to evaluate the teratogenic potential of pulsed‐wave (pw) ultrasound in rats, in the absence of maternal anesthesia or restraint. Pregnant CD rats, trained to remain immobile in a waterfilled ultrasound exposure tank, were scanned with 3‐MHz pw ultrasound at levels of 0, 2, 20 or 30 W/cm2 lSPTA (spatial peak, temporal average intensity) on gestational days 4–19 for approximately 10 min/day. Examination of fetuses on E20 revealed no increase in skeletal or visceral malformations in groups exposed to pw ultrasound in utero. The number of implantations/dam was significantly increased in all pw ultrasound exposure groups compared to sham‐exposed animals and, in a possibly related finding, resorptions were increased in the two highest exposure groups. Although significantly increased compared to controls, resorption frequencies in these groups were low (<10%). No exposure‐related changes in fetal weights were observed in offspring of rats scanned with pw ultrasound during gestation. The results indicate that, under the conditions described, no overt embryotoxicity is associated with gestational exposure to pw ultrasound intensities of up to 30 W/cm2. © 1994 Wiley‐Liss, Inc.
The teratogenic effects of valproic acid in human chondrogenesis in vitro
Authors: Aulthouse Amy Lynn , Hitt Daron C.
Published: June 2005

The anticonvulsant drug valproic acid (VPA) is a known teratogen in humans. In general, anticonvulsants effect major systems in the embryo causing craniofacial, cardiovascular, neurological, urogenital, and major and minor skeletal defects. The limb defects associated with in utero VPA exposure include digital hypoplasia, ectrodactyly, radial ray aplasia, and proximal phocomelia. Human studies are limited to case reports and to retrospective and/or prospective studies. Although animal studies have demonstrated a teratogenic effect of VPA on skeletogenesis, these doses were well above the human therapeutic dose which makes extrapolation from these studies to humans difficult. The purpose of this research was to evaluate the potential deleterious effects of VPA on chondrogenesis, a process that occurs in human limb formation. To accomplish this goal, human chondrocytes were cultured in a three dimensional agarose gel and treated with VPA. The use of this model system was a novel approach to evaluate the teratogenic potential of VPA during chondrogenesis. The influence of VPA on human chondrocytes was monitored using histochemical, immunocytochemical, and morphological techniques. There was a decrease in mitotic activity and the extracellular matrix was modified. At human therapeutic doses, immunofluorescence revealed that type II collagen was reduced, while type I collagen increased. In addition, the alcian blue‐staining matrices (i.e., sulfated proteoglycans) were reduced. Moreover, the Golgi apparatus had swelling in the trans‐face cisternae suggesting that proteoglycan synthesis may be altered. © 1994 Wiley‐Liss, Inc.
D‐mannitol, a specific hydroxyl free radical scavenger, reduces the developmental toxicity of hydroxyurea in rabbits
Authors: Desesso John M. , Scialli Anthony R. , Goeringer Gerald C.
Published: June 2005

Hydroxyurea (HU) is a potent mammalian teratogen. Within 2–4 hours after maternal injection, HU causes 1) a rapid episode of embryonic cell death and 2) profound inhibition of embryonic DNA synthesis. A variety of antioxidants delays the onset of embryonic cell death and reduces the incidence of birth defects. Antioxidants do not block the inhibition of DNA synthesis, indicating that early embryonic cell death is not caused by inhibited DNA synthesis. We have suggested that some HU molecules may react within the embryo to produce H2O2 and subsequent free radicals, including the very reactive hydroxyl free radical. The free radicals could cause the early cell death; antioxidants are believed to terminate the aberrant free radical reactions resulting in lessened developmental toxicity. To investigate whether hydroxyl free radicals cause the early episode of cell death, pregnant New Zealand white rabbits were injected subcutaneously on gestational day 12 with a teratogenic dose of HU (650 mg/kg) in the presence or absence of 550 mg/kg of D–mannitol (Man), a specific scavenger of hydroxyl free radicals. Osmotic control rabbits received HU plus 550 mg/kg of xylose (Xyl, a nonactive aldose). At term, the teratologic effects of HU were ameliorated by Man as evidenced by decreased incidences of the expected limb malformations. Xyl exerted no demonstrable effect on HU teratogenesis. Histological examination of limb buds at 3–8 hours after maternal injection, showed that Man delayed the onset of HU–induced cell death by as much as 4 hours. Xyl had no effect. That Man acts within the embryo was shown by performing intracoelomic injections on alternate implantation sites with Man, Xyl, or saline followed by subcutaneous injection of the pregnant doe with HU. Embryos were harvested 3–8 hours later. Limb buds from saline– and Xyl–injected embryos exhibited the typical pattern of widespread HU–induced cell death at 3–4 hours, whereas Man–injected embryos did not exhibit cell death until 5–8 hours. These results are consistent with those reported for antioxidant–mediated amelioration of HU–induced developmental toxicity and with the hypothesis that hydroxyl free radicals are the proximate reactive species in HU–induced early embryonic cell death. © 1994 Wiley‐Liss, Inc.
Dysmorphogenic effects of nitric oxide (NO) and NO‐synthase inhibition: Studies with intra‐amniotic injections of sodium nitroprusside and NG‐monomethyl‐L‐arginine
Authors: Lee Qwihee P. , Juchau Mont R.
Published: June 2005

Sodium nitroprusside (SNP), a chemical that is readily converted to nitric oxide (NO) in biological systems, was microinjected into the amniotic fluids of cultured whole rat conceptuses on day 10.5 of gestation and dysmorphogenic/embryotoxic effects were evaluated after a 24 hr incubation period. Injections of 217 ng/embryo (∼800 μM) resulted in whitened zones of dead cells in a discretely circumscribed region within the mesencephalon closely associated with the neural tube. These zones were observed with a high incidence after SNP microinjections and were referred to as “white caps” because of their microscopic appearance. At higher concentrations, the whitened zone extended into the rhombencephalon and occasionally appeared to extend the full length of the dorsal midline. The whitened zones of tissue separated readily from the apparently normal underlying tissues upon removal or disturbance of the amniotic membrane. Coinjection of ferrous hemoglobin with SNP selectively prevented the appearance of “white caps” but not other embryotoxic manifestations. Microinjections of the breakdown products of light‐exposed SNP elicited generalized embryotoxicity but “white caps” were not observed. In separate experiments, we found that embryonic enzymes catalyzed significant conversion of arginine to citrulline, indicating expression of NO‐synthase during organogenesis. NG‐monomethyl‐L‐arginine (L‐NMMA), a specific inhibitor of NO‐synthase, was microinjected (50–150 ng/embryo; ∼200–600 μM) on day 10.5 of gestation and produced malformations that differed markedly from those elicited by SNP. Failure of anterior and posterior neural tube closure and profound underdevelopment of the hyoid arch and optic cup were observed at concentrations that produced no apparent growth deficit. These studies with SNP and L‐NMMA indicated that both an excess and a deficiency of NO can be embryotoxic/dysmorphogenic and suggest important roles for optimal levels of NO and NO synthases in normal embryonic development. © 1994 Wiley‐Liss, Inc.
Effects of prenatal exposure to cocaine on heart rate and nonassociative learning and retention in infant rats
Authors: Heyser Charles J. , McKinzie David L. , Athalie Felixia , Spear Norman E. , Spear Linda Patia
Published: June 2005

Nonassociative learning and retention were assessed in terms of habitution of a heart‐rate (HR) orienting response (bradycardia) to a tone in 16‐day‐old male and female rats prenatally exposed to cocaine and in control offspring. Offspring were derived from Sprague‐Dawley dams given daily subcutaneous injections of 40 mg/kg/3 cc cocaine HCI (C40) from gestational days 8–20, pair‐fed control dams given saline injections (PF), and nontreated control dams (LC). Each pup was adapted to the test apparatus for 15 min prior to being given 10 presentations of a pulsing tone, each separated by a 65‐sec intertrial interval, with HR measured during a 5‐sec pretone period and throughout the 10‐sec tone for each trial. To assess retention, subjects were given 10 additional tone trials either 1, 2, 4, or 6 hr later. C40 male offspring displayed significantly lower basal HR following the initial 15‐min isolation period than either LC or PF offspring, whereas prenatal treatment had no effect on basal HR among females. Although no differences were seen in rate of habituation, prenatal cocaine exposure was observed to affect retention of the habituated orienting response. Whereas LC and PF offspring retained habituation of the orienting response for less than 4 hr, C40 offspring exhibited no forgetting after a 4‐hr interval, and showed significant loss of the habituation response only after a 6‐hr interval. © 1994 Wiley‐Liss, Inc.
Human fetal somatic and visceral morphometrics
Authors: Barr Mason , Blackburn Will R. , Cooley N. Reede
Published: June 2005

Because of the increasing prenatal use of high‐resolution ultrasonography to assess fetal growth and because growth aberration is one of the principal manifestations of abnormal intrauterine development, a more precise definition of normal growth is desirable. Our data set from autopsies of fetuses/neonates (50–4,000 g), collected with systematic attention to precision of measurement, is analyzed and presented. Previous computations of fetal growth curves appear to overstate the variation about the mean. Through the identification and exclusion of outliers and the use of appropriate curve fitting techniques, the problem of overestimation of variation about the mean has been largely eliminated. The new growth standards we present can be used to assess aberration from proportional growth and correlate it with gestational circumstances and particular morphological features of the fetus. © 1994 Wiley‐Liss, Inc.
Optic nerve hypoplasia: Comparative effects in children and rats exposed to alcohol during pregnancy
Authors: Strömland Kerstin , Pinazo‐Durán Maria Dolores
Published: June 2005

Children with the fetal alcohol syndrome often have ocular anomalies. These include abnormalities of the eyes and adnexa (strabismus, blepharoptosis, epicanthus), as well as intraocular defects (cataract, glaucoma, persistent hyperplastic primary vitreous, retinal and optic nerve anomalies). Based on the clinical results in an ophthalmological study of a group of Swedish children with the fetal alcohol syndrome, in which optic nerve hypoplasia was found in up to one‐half of the group, an experimental study was designed in rats pre‐ and perinatally exposed to alcohol by means of a liquid diet. The optic nerve was seriously affected. Macroglial cells and optic axons were ultrastructurally damaged. The diameter of the optic nerve cross section, glial cell nuclear area, axonal diameter, and the total number of optic axons showed significantly lower values in the alcohol‐exposed group than in the controls. In addition, the retina from the alcohol‐exposed animals displayed significantly lower values of the retinal thickness and ganglion cell nuclear volume, as compared to the controls. Thus, rats exposed to alcohol in utero developed hypoplasia of the optic nerve similar to the findings in children born to alcoholic mothers. This strongly supports the hypothesis that prenatal alcohol exposure may adversely affect the development of the optic nerve. © 1994 Wiley‐Liss, Inc.
Risk factors for hypoplastic left heart syndrome
Authors: Tikkanen Jorma , Heinonen Olli P.
Published: June 2005

A case‐control study was performed in Finland to investigate the etiology of the lethal heart malformation, hypoplastic left heart syndrome (HLHS). The cases represented all verified HLHS (n = 34) in Finland during 1982‐1983, and controls (n = 756) were randomly selected from all babies born during the same period. Both case and control mothers were interviewed by midwives approximately 3 mo after delivery. Maternal upper respiratory infection during the first trimester of pregnancy was a significant risk factor for HLHS (OR = 2.5, Cl95 = 1.2–5.4). Maternal exposures at work to factors such as disinfectants, pesticides, dyes, lacquers or paints, and anesthetic gases were rare and failed to indicate any risk for HLHS. Maternal use of deodorants or hairsprays during the first trimester of pregnancy was not a significant rick factor for HLHS (OR) = 1. 8, Cl95 = (0.9–3.6). The risk of HLHS was not associated with seasonal variation, maternal smoking, alcohol or coffee consumption, or use of acetosalicylic acid.

Because the study material is limited in size, the power of this investigation or weak for testing the teratogenicity of specific chemicals on the risk of HLHS. Thus, conclusions from the negative findings of this study should be drawn very carefully. © 1994 Wiley‐Liss, Inc. © 1994 Wiley‐Liss, Inc.
Behavioral teratologic effects of prenatal exposure to continuous‐wave ultrasound in unanesthetized rats
Authors: Vorhees Charles V. , Acuff‐Smith Karen D. , Schilling Mary A. , Fisher J. Edward , Meyer Richard A. , Smith Nadine B. , Ellis D. Scott , O'Brien William D.
Published: June 2005

While there are no known risks associated with diagnostic ultrasound, uncertainty about the safety of prenatal ultrasound exposure remains. The purpose of the present experiment was to evaluate the behavioral teratogenic potential of continuous‐wave (cw) ultrasound in rats, in the absence of maternal anesthesia or restraint. Pregnant CD rats, trained to remain immobile in a water‐filled ultrasound exposure tank, were scanned with 3 MHz cw ultrasound at levels of 0, 2, 10, 20, or 30 W/cm2|SPTA(spatial peak, temporal average intensity) on gestational days 4–20 for approximately 10 min/day. Offspring were examined postnatally for survival, growth, physical landmarks of development, behavioral development, and the adult functions of locomotor activity, learning and memory, and startle reactivity. No effects of prenatal ultrasound were found on maternal characteristics, offspring survival or growth, physical or behavioral landmarks of development, or adult tests of passive avoidance or startle. Effects at the highest intensity were obtained on corner and side locomotor activity and in a multiple‐T water maze on measures of errors of commission and time spent finding the goal. The results showed that prenatal cw ultrasound in rats can induce effects on some postnatal neurobehavioral functions at high exposure intensities (30 W/cm2), but at lower intensities (2–20 W/cm2) no consistent evidence of neurobehavioral effects was observed. © 1994 Wiley‐Liss, Inc.
Exposure of Drosophila melanogaster embryonic cell cultures to 60‐Hz sinusoidal magnetic fields: Assessment of potential teratogenic effects
Authors: Nguyen Paul , Bournias‐Vardiabasis Nicole , Haggren Wendy , Adey W. R. , Phillips Jerry L.
Published: June 2005

There is considerable concern about potential detrimental health effect associated with exposure to environmentally relevant magnetic fields. One specific concern relates to potential effects of magnetic field (MF) exposure on reproduction and development. Consequently, an in vitro teratogenesis (developmental toxicity) assay employing embryonicDrosophilacells has been used to determine whether exposure to a 60‐Hz MF of 100 μT for 16–18 hr is itself teratogenic and whether such an exposure could potentiate the teratogenic response induced by a chemical teratogen (developmental toxicant). The results demonstrated that (1) MF exposure alone did not induce a teratogenic response, whether the MF was oriented parallel or perpendicular to the plane of the culture dishes; and (2) MF exposure did not alter the teratogenic response induced by optimal or suboptimal concentrations of three chemical teratogens (retinoic acid, hydroxyurea, and cadmium). Furthermore, in additional studies, Drosophilaembryos were exposed to 60‐Hz MFs of 10 and 100 μT for 24 hr or for their entire development time (i.e., until adult ecolsion, about 10 days). Results demonstrated that MF exposure did not produce an increase in developmental abnormalities over those observed in unexposed controls.
Antisense inhibition of Engrailed genes in mouse embryos reveals roles for these genes in craniofacial and neural tube development
Authors: Augustine Karen A. , Liu Edison T. , Sadler T. W.
Published: June 2005

The roles ofengrailed‐1 (En‐1) andengrailed‐2 (En‐2) have been investigated during gastrulation and neurulation in mouse embryos. Using antisense oligonucleotides and murine whole embryo culture, early somite embryos were injected with antisense phosphorothioated oligonucleotides directed againstEn‐1 ofEn‐2 transcripts and then grown in vitro for 48 hr. Inhibition ofEn‐1 by antisense targeting during this period resulted in embryos with craniofacial abnormalities, specifically loss of mid‐and hindbrain tissue and hypoplasia in associated neural crest derived areas such as the face and first and second pharyngeal arches. In addition, En‐1 appeared to be essential in early patterning of the neural tube. Embryos removed from culture as 8 hr following injection exhibited undulations in the presumptive spinal cord. Histological analysis of the affected neural tubes at 48 hr showed disrupted cytoarchitecture and in some cases, apparent dorsal‐ventral duplication of the neural tube and underlying notochord. Using S100 beta as a notochord marker, embryos removed from culture at 8 or 12 hr following injection exhibited loss of S100 beta expression in the notochord region subjacent to affected neural tube segments, suggesting that S100 beta, or other notochordal genes, may be downstream components of the En‐1 regulatory cascade. Furthermore, antisense inhibition ofEn‐1 induced caudal dysgenesis, suggesting disruption in primitive streak function. Antisense targeting of En‐2 expression at early somite stages produced few alterations in development, although approximately one third of the embryos exhibited a series of lateral folds in the spinal cord at the level of the forelimb‐bud. Combined injections withEn‐1 andEn‐2 antisense resulted in no novel phenotypes, suggesting that the genes do not possess functional redundancy. © 1995 Wiley‐Liss, Inc.
Aspirin–alcohol interaction in the production of cleft palate and limb malformations in the TO mouse
Authors: Padmanabhan R. , Pallot David J.
Published: June 2005

Our objective in the present study was to determine the effects of alcohol on stages when the limb buds and renal primordia develop in the TO mouse and to see if aspirin pretreatment would prevent these organ systems from being malformed as was shown by Randall et al. ('91) in the C57 mice. On one of days 9‐12 of gestation, groups of TO mice were injected intraperitoneally (IP) with a single dose of 200 mg/kg of aspirin, or a proportionate volume of physiological saline. An hour later, half of the aspirin‐treated animals received a single dose of 0. 03 ml/g of freshly prepared 25% (v/v) solution of absolute alcohol and the other half received a proportionate volume of saline. Half of the saline‐treated animals received a single dose of 0.3 ml/g of saline or a proportionate volume of alcohol solution. All animals were killed on day 18 of gestation. Alcohol significantly increased embryonic resorption and caused remarkable intrauterine growth retardation (IUGR). It also induced arched palate, cleft palate and deformities of the digits with haematomas in a modest number of embryos. Aspirin alone did not have teratogenic effects. Pretreatment with aspirin significantly augmented alcohol‐induced resorption, IUGR, cleft palate and digital malformations associated with haematomas. Chronological observations on the development of the treated limbs showed the occurrence of vascular stasis, haematomas, edema and cell death at early stages. Subsequently, digital rays were either destroyed (ectrodactyly) or remained hypoplastic (brachydactyly). It appears that limb development in the aspirin‐ and alcohol‐treated TO mouse embryos is largely affected by vascular disruption. These data provide further evidence to our earlier observation that alcohol and aspirin interact in the production of malformations and that the teratogenic effects of alcohol in the TO mouse are possibly not mediated via treatment related prostaglandin elevation. © 1995 Wiley‐Liss, Inc.
Estimating intracellular pH in developing rodent embryos using a computer imaging technique: Changes in embryonic pH and proliferation rates following maternal treatment with acetazolamide
Authors: Schreiner Claire M. , Collins Michael D. , Scott William J. , Vorhees Charles V. , Colvin Jan , McCandless David
Published: June 2005

Using the transplacental distribution of the weak acid 5,5‐dimethyloxazolidine‐2,4‐dione (DMO), a computer assisted imaging technique has been developed to permit the estimation of intracellular pH (pHi) in very specific areas of the developing rodent embryo. The study reported here demonstrates the heterogeneity of radiolabeled DMO distribution in the developing mouse forelimb. The pattern of pHi distribution shifts from one of high pHi values in the proximal core of the mesoderm on day 10 of gestation to one of higher pHi values in the mesoderm just underlying the ectoderm on day 11. Studies [Scott et al. (1990) Toxicol. Appl. Pharmacol. 103:238‐254] in which DMO concentration was monitored following treatment with acetazolamide or acetazolamide plus amiloride were done in whole embryo homogenates or pooled limb samples which allow for the calculation of an average pHi but may not reflect the pHi in very specific locations of the limb. Two hours after acetazolamide administration, the pHi pattern was not significantly changed from control. Intracellular pH was raised above control levels but was not significant statistically except in the peripheral mesoderm in the ventral third of the forelimb. Fifteen hours after acetazolamide treatment, there was a significant decrease in pHi values with no change in pattern. However, treatment with acetazolamide plus amiloride for 15 hr produced a marked reduction of pHi values throughout the forelimb bud. Changes in bromodeoxyuridine labeling index (an indication of proliferative activity) following treatment with acetazolamide or acetazolamide plus amiloride are reported. The combination treatment reduced the labeling index by approximately 15% below that of control embryos in the limb region where absence of digit(s) will occur. However, we found no overall correlation of proliferative rate and pHi of limb bud mesoderm in treated embryos. Consequently, we were unable to causally associate reduced pHi with decreased proliferative rate. © 1995 Wiley‐Liss, Inc.
Population‐based study of tracheoesophageal fistula and esophageal atresia
Authors: Torfs Claudine P. , Curry Cynthia J. R. , Bateson Thomas F.
Published: June 2005

From a multiracial population of 1,035,384 births monitored by the California Birth Defects Monitoring Program (CBDMP) from 1983 to 1988, we ascertained 34 cases of esophageal atresia (EA), 204 cases of tracheoesophageal fistula (TEF) with an EA (TEF/EA), and 54 cases of TEF without EA. The total prevalence rate was 2.82 per 10,000 live births and stillbirths and showed no secular trend nor marked seasonal variation. Rates of multiple birth were high for each defect (TEF 3.7%, TEF/EA 4.9%, EA 8.8%; population 1.1%). Non‐Hispanic whites were overrepresented for TEF and TEF/EA, but not for EA. EXcluding trisomies, mean maternal age was above the population mean (26.8 years) for TEF (27.9 years) and TEF/EA (28.0 years), but not for EA (26.2 years). The proportion of trisomies was significantly higher for EA (23.5%) than for TEF (9.3%; p<0.02) or for TEF/EA (7.4%, p<0.003). We subdivided each defect into five mutually exclusive types: isolated, multiple, syndromic, chromosomal, and trisomic. Male‐to‐female (M/F) ratios varied considerably between types, both within and between defects. The highest M/F ratios within each defect were for the multiple type (TEF 2.29, TEF/EA 1.44, EA 1.33; population 1.05), and the lowest for trisomies (TEF 0.25; TEF/EA 0.25, and EA 0.60). All types excepttrisomies were significantly associated with a single umbilical artery. We found an association of EA and TEF/EA with dextrocardia (3.1% of cases), and confirmed the association of primary hydrocephalus with TEF and TEF/EA (2.7% of cases). The proportion of cases with additional midline defects or VATER or VACTERL type anomalies was similar for all three defects, suggesting a common developmental pathogenesis. Epidemiologic differences between defects, and between types within defects, may reflect differences in timing of the pathological process or differences in susceptibilities (e.g., by sex or aneuploidy) and emphasize the need to evaluate each defect and its types separately in epidemiologic studies. © 1995 Wiley‐Liss, Inc.
Effect of supplemental folic acid on valproic acid‐induced embryotoxicity and tissue zinc levels in vivo
Authors: Hansen Deborah K. , Grafton Thomas F. , Dial Stacey L. , Gehring Theresa A. , Siitonen Paul H.
Published: June 2005

Valproic acid (VPA) is an anticonvulsant drug known to cause spina bifida in humans. Administration of the vitamin, folic acid has been reported to decrease the frequency of VPA‐induced exencephaly in mice treated with the drug in vivo. A protective effect by folinic acid has not been observed in vitro. The purpose of this investigation was to reexamine the ability of folinic acid to decrease the incidence of VPA‐induced neural tube defects in vivo. We also examined the effect of increased intake of folic acid on zinc levels in various maternal and embryonic tissues. Folinic acid, whether administered by intraperitoneal injection or in osmotic mini‐pumps, did not decrease the number of mouse fetuses with VPA‐induced exencephaly. Dietary supplementation with 10–20 times the daily required intake of folic acid in rodents also failed to decrease the embryotoxicity of VPA. Such dietary supplementation had no effect on zinc levels in maternal liver, brain, or kidney, nor in embryonic tissues. These results indicate that folic acid is not able to reverse the embryotoxicity induced by the anticonvulsant, that there is no apparent effect of high dietary folate intake on maternal or embryonic zinc levels and suggest that folate is probably not involved in the mechanism of VPA‐induced embryotoxicity. © 1995 Wiley‐Liss, Inc.
Urinary steroid evaluations to monitor ovarian function in exotic ungulates: I. Pregnanediol‐3‐glucuronide immunoreactivity in the okapi (Okapia johnstoni)
Authors: Loskutoff N. M. , Ott J. E. , Lasley B. L.
Published: June 2005

Immunoreactive pregnanediol‐3‐glucuronide was assessed in daily urine samples from five female okapis. Indexed by creatinine (CR), the resultant profiles accurately reflect ovulation and pregnancy in this species. The infertile cycle was approximately 14.5 days by this method with the preovulatory levels averaging less than 1 ng/mg CR (N = 88) for approximately eight days (N = 28). Postovulatory levels averaged 24 ng/mg CR (N = 55) in one female and 12 ng/mg CR (N = 27) in another for approximately six days (N = 26). Pregnancy is confidently detected by three weeks postcoition by elevated pregnanediol levels that remain significantly higher that luteal phase levels until weeks before parturition.