Free blastocyst and implantation stages in the European brown hare: correlation between ultrasound and histological data.

The European brown hare (Lepus europaeus) is the only species with superconception, whereby the maternal reproductive tract hosts two sets of conceptuses at different developmental stages. The embryonic development of the hare has not yet been described. To understand the mechanism of superconception, we studied oviduct transport and implantation stages by embryo flushing and live high-resolution ultrasound. Ultrasound data of implantation stages is correlated with histology. In the oviduct, a mucin coat is deposited on the zona pellucida. The blastocysts enter the uterine horns on Day 5, 1 day later than in the rabbit, and directly expand approximately threefold. Spacing is accompanied by peristaltic movement of the endometrium. The mucin coat disappears and the conceptuses attach. The yolk-sac expands in the blastocoel and syncytial knobs invade the antimesometrial endometrium. Maternal blood lacunae appear in the mesometrial endometrial folds, which are subsequently invaded by the syncytiotrophoblast. The haemochorial chorioallantoic placenta forms. The yolk-sac cavity is gradually replaced by the allantois and finally by the exocoel. The different reproductive strategies of the precocial hare and the altricial rabbit are discussed. We assume that the lagomorph-specific mucin coat and the hare-specific delay of the oviduct-uterine transition are prerequisites for superconception.

Allantoid cyst in the umbilical cord diagnosed with B-flow ultrasound.

Allantiod cysts are true cysts in the umbilical cord. They arise from persistent structures of allantois, and the cysts are filled with urine because of a connection to the urinary bladder. Allantoid cysts are located centrally in the umbilical cord and separate the umbilical cord vessels. B-flow ultrasound is a new technique illustrating blood flow. This method is independent of the insonation angle and therefore superior to Doppler ultrasound visualising long segments of vessels with a winding course. The authors present a case with allantoid cysts diagnosed with B-flow ultrasound.

Allantoic cysts and posterior urethral valves: a case report.

Allantoic cysts are a somewhat rare entity. They are identifiable on antenatal ultrasound examination but are not easily distinguishable from pseudocysts, which are often associated with a poor prognosis. Their etiology remains obscure and obstructive uropathies have been proposed to be one of the underlying mechanisms. We report on a case in which both allantoic cysts and a patent urachus were detected antenatally and turned out to be associated with posterior urethral valves (PUV). The cysts were first seen in the early second trimester, with a full fetal bladder and patent urachus. They disappeared by the 29(th) week. During the subsequent sonographic examinations, the bladder was emptying regularly. The kidneys remained normal throughout the pregnancy. It is hypothesized that the increased pressure within the urinary tract kept the urachus patent, led to the formation of allantoic cysts and, later, to their perforation; this allowed the fetus to empty his bladder and kept him from the usual complications of PUV. This case emphasizes the importance of detection and characterization of umbilical cord cysts on antenatal ultasound examination and suggests that obstructive uropathies should be included in the differential diagnosis of umbilical cord cyst communicating with the fetal bladder.

Umbilical cord cysts of allantoic and omphalomesenteric remnants with progressive umbilical cord edema: a case report.

We present a unique case of umbilical cord cysts of allantoic and omphalomesenteric remnants with progressive cord edema during pregnancy. Enlargement of the umbilical cord was observed initially at 28 weeks' gestation; the cord cysts were first recognized at 17 weeks. At 37 weeks, a cesarean section was performed and a male infant weighing 2,300 g was delivered. The entire length of the umbilical cord was 80 cm; the 50-cm proximal portion was strikingly edematous and was 7 cm in diameter. On the 1st day of life, operative exploration was undertaken via an infraumbilical incision. It was evident that a patent urachus protruded from the bladder. The lesion was excised and the bladder was closed in a two-layer anastomosis. Histologically, the intestinal epithelium was connected to the transitional epithelium at the top of the urachus, indicating allantoic remnants fused with omphalomesenteric remnants. Such a case has not been reported previously. It was considered that the overflow of urine from allantoic remnants to omphalomesenteric remnants caused the extraordinary edema of the umbilical matrix. Based on our experience, finding progressive umbilical cord edema may indicate a patent urachus co-existing with allantoic and omphalomesenteric remnants.

Evaluation of early fetal loss induced by gavage with eastern tent caterpillars in pregnant mares.

OBJECTIVE: To determine whether gavage of pregnant mares (housed without access to pasture) with starved eastern tent caterpillars (ETCs) or their excreta is associated with early fetal loss (EFL), panophthalmitis, or pericarditis. DESIGN: Randomized clinical trial. ANIMALS: 15 mares. PROCEDURE: 15 mares with fetuses from 40 to 80 days of gestation (dGa) were randomly assigned to 1 of 3 groups and received 2.5 g of ETC excreta, 50 g of starved ETCs, or 500 mL of water, respectively, once daily for 10 days. Mares were housed in box stalls, walked twice daily, and not allowed access to pasture for 12 days before or during the 21-day trial. RESULTS: 4 of 5 mares gavaged with starved ETCs (group 2) aborted on trial days 8 (2 mares), 10, and 13. No control mares or mares that received excreta aborted. Differences between the ETC group and other groups were significant. Abortion occurred on 49, 64, 70, and 96 dGa. Allantoic fluids became hyperechoic the day before or the day of fetal death. Alpha streptococci were recovered from 1 fetus and Serratia marcescens from 3 fetuses. Neither panophthalmitis nor pericarditis was seen. The abortifacient component of the ETCs was not elucidated. CONCLUSIONS AND CLINICAL RELEVANCE: These findings suggest that mares with fetuses from 40 to 120 days of gestation should not be exposed to ETCs because they may induce abortion.

A case of fetal vesicoallantoic cyst in the umbilical cord.

A vesicoallantoic cyst in the umbilical cord was detected by fetal ultrasonography at 16 weeks of gestation. The blood flow through the umbilical vessels was evaluated with periodic color Doppler ultrasonographic examinations because compression by the cyst may cause reduction in blood flow and lead to fetal death. After disappearance of the cyst, the infant was delivered vaginally. Retrograde cystography revealed a narrow channel between the bladder and the navel, confirming patent urachus, which was resected without any complications.

Unusual fate of vesicoallantoic cyst with non-visualization of fetal urinary bladder in a case of patent urachus.

We present the sonographic findings of a fetus with a vesicoallantoic cyst. The cyst was first identified at 17 weeks of gestation; it was associated with an omphalocele, and disappeared spontaneously at 29 weeks. The fetal urinary bladder was not visualized thereafter. An omphalocele and exstrophia of the urachus were found at birth and repaired. Non-visualization of the fetal urinary bladder suggested rupture of the covering membrane of the omphalocele and allantois during fetal life. A defect in the wall of the omphalocele supported our hypothesis.

Hydrallantois in a caprine doe.

Hydrallantois was diagnosed in a 5-year-old Toggenburg doe. Clinical signs included bilateral abdominal distention, anorexia, and recumbency. Ultrasonographically, excessive fluid and live fetuses were detected in the uterus. At the time of cesarean section, the fluid (approx 12 L) was determined to be in the allantoic cavities; concentrations of electrolytes in the fluid were similar to concentrations in allantoic fluid from cows with hydrallantois. Two viable fetuses and 1 nonviable fetus were delivered. The doe retained its placentas for 60 hours, but made a good recovery. Hydrallantois should be considered in the differential diagnosis of abdominal distention in caprine does in late gestation.