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A stillborn bovine male fetus with abdominal distention, arthrogryposis and atresia ani was presented for diagnostic evaluation. At necropsy, this fetus had a large amount of ascites, urachal obstruction and marked bladder distention. The ventral surface of the bladder had ruptured and attached to the abdominal wall by fibrinous adhesions. There was bilateral hydronephrosis with moderate pelvic dilatation and cortical attenuation. The rectum was filled with meconium but the anus was imperforate. The right forelimb was contracted. The cause(s) of these abnormalities could not be determined; however, we believe that developmental abnormalities during embryogenesis may be the result of chromosomal abnormalities.

The expression of inducible nitric oxide synthase (iNOS), an enzyme that produces nitric oxide, was examined in the hearts of pigs infected with porcine enterovirus serotype 3 (PEV3). Piglets orally infected with PEV3 developed tremors and paralysis 3-7 days post-infection. Affected animals had pericarditis and myocarditis. There were fibrin and inflammatory cell infiltrates (macrophages and neutrophils) in the pericardial sac and myocardium. Immunohistochemically, the majority of inflammatory cells in the pericardial sac were positive for iNOS and nitrotyrosine, an end product of nitric oxide. These results suggest that iNOS is upregulated in the pericardial lesion, and that increased nitric oxide production plays an important role in the development of PEV3-induced pericarditis and myocarditis.

A 10-day-old male Holstein dairy calf with orthopaedic abnormalities was unable to stand but was alert with a suckle reflex. At necropsy, the calf showed multiple defects, including partial agenesis of the left rib plate, deformed left scapula, shortened left humerus, agenesis of the left kidney, atresia ani and scoliosis. The cause of these anomalies could not be determined. This report is the first to describe partial agenesis of ribs in a calf.

To establish a prediction table of parturition day the real-time B-mode ultrasonographic examinations were performed in the 8 pregnant Malteses and 10 Yorkshire terriers (total pups, 25 and 38 pups, respectively) from 18 days of gestation until the parturition. Ovulation was designated the first day of gestation (day 0). Extra fetal and fetal structures were measured from all conceptues. The parameters that exhibited the best correlation to parturition were used to compile a prediction table of parturition day. To testify the precision of the prediction table of parturition day, the 15 pregnant Malteses (48 pups) and 13 pregnant Yorkshire terriers (42 pups) with unknown mating time were examined using ultrasonography. Inner chorionic cavity diameter on days 18 to 37 and fetal head diameter on day 38 to parturition that showed the best correlation to gestational age were the most pertinent to the estimation of gestational age and the prediction of parturition day. The two parameters were used to compile a prediction table of parturition with averaged regression equations. In verificational examinations, with the exception of I Yorkshire terrier (3.6%) having 1 fetus, 18 of 28 bitches (64.3%) delivered exactly on the date predicted and 9 of 28 bitches (32.1%) delivered within I day of the date predicted. Therefore, the prediction table of parturition day seems to be a useful tool of the prediction of parturition day in practice.

A 10-day old male calf exhibited multiple congenital anomalies of the urinary and gastrointestinal tracts, including renal fusion (horseshoe kidney), ureteral fusion, rectovesicular fistula, and atresia ani. In horseshoe kidney, the organs were fused together at the caudal poles. The left kidney and cranial half of right kidney were shrunken, while the remaining lobules were hypertrophic. Ureters were fused cranially and bifurcated caudally. The terminal rectum was narrowed and connected with the bladder. The anus was imperforate. The cause of these anomalies could not be determined.

The objective of this investigation was to evaluate dose-incidence relationships on the prenatal effects of gamma-radiation. Pregnant ICR mice were exposed on day 11.5 after conception, coincident with the most sensitive stage for the induction of major congenital malformations, with 0.5-4.0 Gy of gamma-radiations. The animals were sacrificed on day 18 of gestation and the fetuses were examined for mortality, growth retardation, change in head size and any other morphological abnormalities. With increasing radiation dose, incidence of small head, growth retarded fetuses, cleft palate, dilatation of cerebral ventricle and abnormalities of the extremities in live fetuses rose. The threshold doses of radiation that induced cleft palate and dilatation of cerebral ventricle, and abnormal extremities were between 1.0 and 2.0 Gy, and between 0.5 and 1.0 Gy, respectively.

The objective of this investigation was to evaluate the influence of gestational age at exposure on the prenatal effects of gamma-radiation. Pregnant ICR mice were exposed to a single dose of 2.0 Gy gamma-radiation at a gestational 2.5 to 15.5 days post-coitus (p.c.). The animals were sacrificed on day 18 of gestation and the fetuses were examined for mortality, growth retardation, change in head size and any other morphological abnormalities. The only demonstrable effect of irradiation during the preimplantation period was an increase in prenatal mortality. Resorptions were maximal on post-exposure day 2.5 after conception. The pre-implantation irradiated embryos which survived did not show any major fetal abnormalities. Small head, growth retardation, cleft palate, dilatation of the cerebral ventricle, dilatation of the renal pelvis and abnormalities of the extremities and tail were prominent after exposure during the organogenesis period, especially on day 11.5 of gestation. Our results indicate that the late period of organogenesis in the mouse is a particularly sensitive phase in terms of the development of the brain, skull and extremities.