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Biomedical subjects

L Shenker

Publications and source records attributed to L Shenker.

At least 37 records · Page 2Linked to original sources
PubMed1986

Doppler echocardiographic studies of diastolic function in the human fetal heart: changes during gestation.

With the combined use of two-dimensional ultrasound and Doppler echocardiography, noninvasive examination of the human fetal heart and circulation has recently become possible. These techniques were employed to investigate diastolic atrioventricular valve flow in the fetal heart in 120 fetuses studied between 17 and 42 weeks of gestation. Two-dimensional ultrasound was used to examine fetal and intrauterine anatomy, and estimates of gestational age were made based on biparietal diameters and femur lengths. Doppler echocardiography was performed with a 3.5 or 5 MHz Doppler sector scanner. Flow velocity patterns were obtained through the tricuspid and mitral valves during diastole. Peak flow velocity during late diastole or atrial contraction (A) was compared with peak flow velocity during early diastole (E) in four groups of fetuses: Group 1, 17 to 24 weeks of gestation; Group 2, 25 to 30 weeks; Group 3, 31 to 36 weeks; and Group 4, 37 to 42 weeks. The ratio of A to E decreased significantly as gestational age advanced, from 1.56 +/- 0.06 (+/- SE) to 1.22 +/- 0.03 across the tricuspid valve (p less than 0.001) and from 1.55 +/- 0.04 to 1.22 +/- 0.06 across the mitral valve (p less than 0.001). In tricuspid valve measurements, peak flow velocity during early diastole increased from 26.3 +/- 2.0 cm/s in Group 1 to 36.5 +/- 1.7 cm/s in Group 4 (p less than 0.001), whereas peak flow velocity during atrial contraction did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1986

Cardiac Doppler flow velocities in human fetuses.

Cardiac Doppler flow velocity studies were performed in normal human fetuses between 18 and 40 weeks of gestation. Two-dimensional linear array and sector scanning techniques were used for the initial evaluation of the fetuses, which included a standard ultrasound examination to determine normal anatomy and estimated gestational age and weight. Fetal cardiac ultrasound examination was then performed, with four-chamber, short-axis/great vessel, long-axis/left ventricular outflow tract, and aortic arch views obtained. Pulsed echo Doppler instrumentation was used to obtain flow velocity measurements through the tricuspid, pulmonary outflow, mitral, and aortic outflow regions. Calculation of transvalve volume flow for mitral and tricuspid valves was performed by combining the valve anulus sizes and calculated mean temporal velocities for the valves. Maximal flow velocities were greater through the tricuspid (mean maximal velocity 51 +/- 1.2 [SE] cm/sec) than through the mitral (47 +/- 1.1 cm/sec; p less than .05) valve regions, with a wide range of scatter for results between fetuses but less than 6% average variation in the individual fetuses during gestation. For 18 fetuses, right heart dimensions and volume flows (mean 307 + 30 ml/kg/min) were greater than left heart dimensions and volume flows (232 +/- 25 ml/kg/min). Doppler echocardiography may prove to be useful as an adjunct to imaging echocardiography for evaluation of fetal cardiac anatomy and function.

Aorta↗
PubMed1986

Embryonic heart rates before the seventh week of pregnancy.

Previous studies of normal human embryonic heart rates showed an increase in the rates between the 7th and 9th gestational weeks; the rates gradually declined thereafter until the 15th week. The present study added new information about embryonic heart rates before the seventh week. The heart rates are slower than those reported to occur after the seventh week. These observations are connected with morphologic and physiologic changes during this period of embryonic life.

Female↗
PubMed1985

Syndrome of camptodactyly, ankyloses, facial anomalies, and pulmonary hypoplasia (Pena-Shokeir syndrome): obstetric and ultrasound aspects.

Two siblings with Pena-Shokeir syndrome are described. This syndrome consists of polyhydramnios, intrauterine growth retardation, short umbilical cord, perinatal death, facial abnormalities, limb abnormalities including arthrogryposis, and lethal pulmonary hypoplasia. The mode of inheritance is most likely autosomal recessive. Prenatal diagnosis was made in the second pregnancy with ultrasound performed at 26 weeks' gestation. The roles of fetal akinesia and fetal apnea in the production of the various manifestations of the syndrome are detailed, and the possibility of early prenatal diagnosis is considered.

Abnormalities, Multiple↗
PubMed1985

SEM-dissection of a human embryo derived from an ectopic pregnancy.

A 6.5-week-old human embryo with an approximate crown-rump length of 13.2 mm was obtained from a tubal pregnancy. Two hours before surgical removal, the embryo was imaged with real time ultrasound and was noted to have rhythmic cardiac motion. Subsequent to surgical removal, the embryo was dissected free from the placenta and prepared for routine scanning electron microscopic (SEM) studies. Progressive stages of dissection with microsurgical instruments followed by SEM photography elucidated the three-dimensional aspects of embryonic development of many structures, including the lens placode, tongue bud, Rathke's pouch, atrial and ventricular foramina, primitive intestinal loop and undifferentiated external genitalia. Almost certainly, such clear views of dissected structures can contribute to our understanding of human embryonic development.

Dissection↗
PubMed1982

Balanced translocation karyotypes in patients with repetitive abortion. Case study and literature review.

Cytogenetic studies were conducted upon 100 consecutive couples with abortions. Eight balanced carrier translocation karyotypes were discovered (8%): three cases of Robertsonian translocations and five reciprocal translocations. Two structural variant karyotypes and a poly-X mosaic were also found. A review of the literature on repetitive abortion revealed 82 balanced translocations in 1,331 couples, a rate of 6.2%. Cytogenetic studied should be routine for patients with repetitive abortion. In the pooled series, 3.7% of couples with translocation had wastage, including some with normal offspring; 9.2% had malformed offspring; 62% of the carrier couples lacked the malformation history. Seventy-four percent of the translocations were reciprocal; risk rates for imbalanced progeny were undefined for 90% of the carrier couples. Only 11 imbalanced conceptuses were demonstrated cytogenetically in 262 pregnancies of the carrier group.

Abortion, Habitual↗
PubMed1979

Fetal cardiac arrhythmias.

Fetal cardiac arrhythmias have been classified and the current literature reviewed. Emphasis is placed on antepartum diagnosis and appropriate therapy. The incidence of congenital heart disease varies with the type of arrhythmia. The differential diagnosis of fetal cardiac arrhythmias and management are discussed.

Adult↗
PubMed1979

Bicornuate uterus with incomplete vaginal septum and unilateral renal agenesis. Ultrasound demonstration in two patients.

Ultrasound studies in two patients revealed identical anomalies consisting of unilateral renal agenesis, bicornuate uterus, communication between the two uterine cavities at a level just above the cervix, and incomplete vaginal septum with a blind hemivagina filled with purulent material. One patient was 28 weeks pregnant at the time of diagnosis and was managed surgically.

Abnormalities, Multiple↗
PubMed1975

Routine electronic monitoring of fetal heart rate and uterine activity during labor.

Routine electronic monitoring has been performed on 2411 labor patients at Booth Memorial Medical Center. Most recently, 88% of all patients delivered were monitored. As a direct result of this program, intrapartum stillbirths have been dramatically reduced from 1.2/1000 livebirths to 0.5/1000 livebirths. Perinatal mortality for fetuses over 1000 g has fallen to 8.8/1000 deliveries. Apgar scores below 6 at 5 minutes have decreased from a rate of 24/1000 to 14/1000 livebirths. No increase in cesarean sections for fetal distress has occurred although the primary cesarean section rate has increased over the past 10 years, apparently unrelated to fetal monitoring. It is strongly recommended that all patients in labor be monitored by currently available technics.

Apgar Score↗