Long‐term effects of a midgestational asphyxial episode in the ovine fetus

Abstract

We and others have shown previously that fetuses at midgestation can survive 30 min of complete umbilical cord occlusion, although hydrops fetalis (or gross fetal edema) results. To investigate whether this hydrops resolves by late gestation and if there are any long-term consequences of the asphyxial insult on the heart and kidneys, eight fetuses were subjected to 30 min of complete umbilical cord occlusion at 0.6 gestation (90 days; term 150 days) and were compared to a sham group (n ¼ 10). During the occlusion period, fetuses became severely hypoxemic, hypercapnemic, and acidotic, with both blood pressure and heart rate decreasing. Most variables had returned to normal by 2-hr recovery. At 129 6 1 days of gestation, approximately 40 days post occlusion, some fetuses were still slightly hydropic as skin fold measurements were increased (P < 0.01), although fetal body weight was not different from the sham group. The two groups had similar heart and kidney weights, ventricular cardiac myocyte nucleation, and glomerular number. By contrast, brain weight was reduced by 37% (P < 0.001) and the cerebral lateral ventricles were grossly dilated. Lungs were 50% smaller than in sham fetuses (P < 0.001). Thus, the hydrops that develops at midgestation as a result of a severe asphyxial episode can, but does not always, fully resolve by late gestation. Also, while fetuses at midgestation can survive this asphyxial episode with no long-term impact in renal or cardiac size, nephron number, or cardiomyocyte nucleation, the brain and lungs are severely affected.

Aberrant gene expression patterns in placentomes are associated with phenotypically normal and abnormal cattle cloned by somatic cell nuclear transfer

“…Therefore, because of the constraints in supplying oxygen and nutrients, the anaerobic pathway may be used more in SCNT placentomes, which would result in pyruvate being reduced to lactate and less ATP production (13). In sheep, asphyxiation of the placenta for 30 min during midterm pregnancy produced phenotypes with similarities to hydrops in cattle (65). On the basis of the DEG found in the SCNT and hydrops comparisons, our data are consistent with the hypothesis that abnormal placental development in clones leads to reduced functioning of the placenta, resulting in less oxygen to the fetus.…”

Glomerular Hypertrophy in Offspring of Subtotally Nephrectomized Ewes

“…The protocol for kidney processing and glomerular counting is detailed extensively by O'Connell et al (2006). The fixed tissue was cut into slices 2 mm thick and each slice cut into pieces 5 mm long.…”

“…Every 10th and 11th sections were mounted onto slides and stained with periodic acid-Schiff reagent (PAS) and counter stained with haematoxylin. Using the physical disector/fractionator technique, the total number of glomeruli (nephrons; N glom,kid ) in the kidney was estimated (O'Connell et al, 2006). Mean glomerular volume and mean renal corpuscle volume were also determined using stereological techniques (O'Connell et al, 2006).…”

“…Using the physical disector/fractionator technique, the total number of glomeruli (nephrons; N glom,kid ) in the kidney was estimated (O'Connell et al, 2006). Mean glomerular volume and mean renal corpuscle volume were also determined using stereological techniques (O'Connell et al, 2006). By multiplying total glomerular number by mean glomerular volume, we calculated the total volume of all glomeruli in kidneys.…”

Filtering the good from the bad: A focus on kidney development and disease to celebrate John Bertram's long‐standing career in anatomy and renal research

“…Indeed, it is John's expertise in stereology that has led to many of his collaborations over his career (Figure 2). Most of the articles that John has published in The Anatomical Record relate to stereological methods and their applications in the biological context (Bertram, Young, Spencer, & Gordon, 2000; Brandon et al, 2008; Foster, Bertram, & Holbrook, 1988; Nurcombe, Wreford, & Bertram, 1991; O'Connell et al, 2006). At The Anatomical Record , the strength of stereological methods in quantitating morphological biological parameters is well recognized and many of the leaders in the stereological field choose to publish in The Anatomical Record on a regular basis.…”