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Biomedical subjects

K Ash

Publications and source records attributed to K Ash.

28 records · Page 2Linked to original sources
PubMed1994

Isolation and partial purification of plasma membrane from porcine oocytes.

Egg plasma membrane (EPM) was isolated in comparatively large amounts from porcine slaughterhouse ovaries. Ovaries were minced, and the oocyte containing fluid was filtered to retrieve zona pellucidae-intact oocytes. The oocytes were homogenized and filtered again to remove zona pellucidae. The egg filtrate was subjected to differential centrifugation to remove membrane bound organelles and the remaining plasma membrane containing material was pelleted by ultracentrifugation. Plasma membranes were further separated from cellular material by sucrose density gradient centrifugation and were collected from portions of the gradient that correspond to the densities of plasma membrane. The purity of isolated plasma membranes was assessed by membrane marker enzyme analysis and transmission electron microscopy. Activities of the plasma membrane marker enzymes 5' nucleotidase and alkaline phosphatase increased from nondetectable levels in the egg filtrate to relatively high levels in the plasma membrane preparation. Marker enzymes for mitochondrial and lysosomal membranes fell from detectable levels in the egg filtrate to levels that were at the lower limits of the assays to detect in the final preparation. Evidence provided by binding of biotin-labeled EPM to capacitated sperm suggests that the isolated EPM retains its biological activity. The procedure presented here represents a novel method of isolating porcine egg plasma membranes for further study involving sperm-egg interaction.

5'-Nucleotidase↗
PubMed1993

Fetal tumors associated with hydrops: the role of the pediatric surgeon.

Fetal tumors are being diagnosed with increasing frequency and great accuracy by antenatal ultrasound. High-output cardiac failure and hydrops indicate fetal distress. Management may be limited by the gestational age of the fetus. Our experience with three fetal tumors demonstrates the dilemma with respect to timing of delivery and prognosis. Following the diagnosis of a large sacrococcygeal tumor, a 22-week-gestation fetus became hydropic and died. Another fetus with a rapidly growing posterolateral chest wall mass required cesarean section delivery at 29 weeks gestation. Postnatal course was complicated by pulmonary hypoplasia, intratumoral hemorrhage, and death. The third fetus had an enlarging tumor in the right lobe of the liver. Poor biophysical profile and mild hydrops necessitated cesarean section delivery at 34 weeks. Right hepatic lobectomy was performed and the infant was subsequently discharged home at one month of age. The deleterious effects of the fetal tumor and the need for its removal have to be carefully weighed against the ability of the fetus to survive postnatally.

Adult↗
PubMed1991

Congenital chylothorax and mediastinal neuroblastoma.

This is the first reported association of congenital chylothorax and mediastinal neuroblastoma in a newborn infant. The infant exhibited features of both congenital and acquired chylothorax. Resolution of the chylothorax occurred following ligation of thoracic duct after failure of conservative management with multiple thoracentesis and chest tube drainage.

Chylothorax↗
PubMed1990

TRAP sequence--successful outcome with indomethacin treatment.

A case of twin reversed arterial perfusion (TRAP) sequence (acardiac twin) complicated by hydramnios was managed by maternal administration of indomethacin. Successful outcome was achieved after 8.5 weeks of therapy with delivery of a normal live-born infant at 34 weeks.

Abnormalities, Severe Teratoid↗
PubMed1990

Fetal echocardiography in Manitoba: a regional perspective.

In order to investigate the impact of detailed fetal echocardiography on perinatal care at a tertiary health care centre, the records of all 29 cases referred for fetal echocardiography during the years 1987-88 were reviewed. All patients had risk factors for offspring with congenital heart disease. A family history of congenital heart disease led to fetal echocardiography in about two-thirds of the cases, while the remainder were referred on the basis of abnormal cardiac screening examinations during fetal assessment. Forty examinations were performed on patients at gestational ages of 16 to 37 weeks. Detailed fetal echocardiography did not alter the perceived severity of major structural cardiac defects previously identified by an experienced fetal assessment unit and did not change or influence intrapartum care. The value of fetal echocardiography in the diagnosis and treatment of fetal tachyarrhythmias was confirmed. Also, fetal echocardiography provided reassurance of cardiac normality in cases with familial and maternal risk factors for congenital heart disease. Fetal echocardiography appears to be an inappropriate screening tool in view of its limited availability and focus. Comprehensive fetal assessment with four chamber cardiac imaging is the appropriate first-line screening test for patients with risk factors for offspring with congenital heart disease.

Echocardiography↗
PubMed1989

Competition between split and nonmanipulated embryos in the production of identical piglets.

The effect of nonmanipulated embryos on in utero survival of split porcine embryos was examined in this study. Previously, only limited success in the production of identical twin piglets has been reported. Embryos were collected from slaughtered donors (4 to 7 d post estrus) and were either split with the aid of a micromanipulator or left as whole embryos. Monozygotic pairs of split embryos were then surgically transferred to recipients with a complement of either split or nonmanipulated embryos. A total of 217 split embryos and 60 nonmanipulated embryos were transferred to 19 recipients. Nine of these recipients farrowed. In the two recipients that received only split embryos and farrowed, 31% of the split embryos survived to term, including two sets of monozygotic twins. In the remaining seven recipients, only 10% of the split embryos that were transferred along with nonmanipulated embryos survived to farrowing. This difference in split embryo survival (31 vs 10%) was significantly different (P<0.005). Sixty-nine percent of the nonmanipulated embryos survived to term in recipients that maintained pregnancy. Data presented in this study suggest that competition occurs between split and nonmanipulated embryos transferred to the same uterine environment.

Journal Article↗
PubMedDate not supplied

Unexpected preterm delivery in tourists: implications for long-distance travel during pregnancy.

From 1984 to 1989, 33 pregnant tourists were delivered of preterm infants requiring neonatal intensive care. We retrospectively reviewed medical records of all high-risk infants delivered to tourists during this period and compared these results with those of a previous review from 1978 to 1984. Thirty-seven infants were admitted during this later period compared with 27 previously observed. Of recent mothers, 30% had identifiable high-risk factors compared with 50% previously studied. Infant demographic and outcome data were similar, except for fewer recent intraventricular hemorrhages. Outcome was adversely affected by maternal high-risk factors during both periods. Pregnant tourists, many with identifiable high-risk factors, continue to be delivered of premature infants who may require prolonged hospitalization. Because of this, and the potential for serious psychosocial and economic consequences of preterm delivery, we recommend that long-distance travel in pregnant women with identified high-risk factors be restricted about the time when viability of the fetus is possible.

Adult↗