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Biomedical subjects

K L Reed

Publications and source records attributed to K L Reed.

At least 55 records · Page 3Linked to original sources
PubMed1993

Basic technique of fetal echocardiography.

The fetal heart is the organ system most commonly affected with congenital disease. Though risk factors exist for congenital heart disease (eg, family history, toxin exposure, maternal illness, abnormal karyotype, and other fetal anomalies), the fetal heart is most often examined as part of a routine evaluation of the fetal anatomy in the fetus with no identifiable risk factors. The importance of a systematic, complete assessment of the cardiac axis cannot be overemphasized. All aspects of sonography (ie, real time, M-mode, pulsed, and color Doppler) can provide unique and integral information in evaluating the fetal heart and thorax.

Echocardiography↗
PubMed1993

Comparison of Doppler with two-dimensional sonography and CA 125 for prediction of malignancy of pelvic masses.

OBJECTIVE: To assess the validity of Doppler flow sonography for the prediction of malignancy in adnexal masses and to compare the results with two-dimensional ultrasonographic examination and CA 125 levels. METHODS: In a cross-sectional study, 55 patients with adnexal masses were examined using Doppler sonography to measure the resistance index of tumor-associated blood flow profiles. In addition, abdominal and transvaginal ultrasound examinations were performed and preoperative CA 125 serum levels were assessed. RESULTS: Sixteen patients had malignant tumors and 39 had benign tumors. A resistance index cutoff of less than or equal to 0.8 showed the highest sensitivity (93.8%), with a specificity of 56.4%, a positive predictive value of 46.8%, and a negative predictive value of 95.7%. Compared with two-dimensional sonographic evaluation using either a scoring system or subjective assessment, and with CA 125 levels, the resistance index showed higher sensitivity and negative predictive value but lower specificity and positive predictive value. False-positive resistance index values were prevalent with endometriosis, leiomyomata, and mucinous cystadenoma. The combination of the resistance index with either the sonographic features or CA 125 increased the sensitivity and negative predictive value to 100%, with only a slight decrease in specificity and positive predictive value, but was not superior to the combination of two-dimensional sonography and CA 125. CONCLUSION: Doppler sonographic evaluation of resistance indexes in the vessels of adnexal masses increased the sensitivity of two-dimensional sonography and CA 125. However, 46% of positive Doppler results were false and 37.5% of the benign tumors had low resistance indexes, thus limiting the validity of this technique for screening programs.

Adnexal Diseases↗
PubMed1992

Isolation and characterization of Chinese hamster ovary cells defective in the intracellular metabolism of low density lipoprotein-derived cholesterol.

We have isolated clones of an established cell line which express defects in intracellular cholesterol metabolism. Chinese hamster ovary cells were mutagenized, and clones unable to mobilize low density lipoprotein (LDL)-derived cholesterol to the plasma membrane were selected. Biochemical analysis of two mutant clones revealed a phenotype characteristic of the lysosomal storage disease, Niemann-Pick type C. The mutant cell lines were found to be defective in the regulatory responses elicited by LDL-derived cholesterol. LDL-mediated stimulation of cholesterol esterification was grossly defective, and LDL suppression of 3-hydroxy-3-methylglutaryl-CoA reductase was impaired. However, the mutants modulated these activities normally in response to 25-hydroxycholesterol or mevalonate. The LDL-specific defects were predicated by the inability of these mutants to mobilize LDL-derived cholesterol from lysosomes. Cell fractionation studies showed that LDL-derived, unesterified cholesterol accumulated in the lysosomes of mutant cells to significantly higher levels than normal, commensurate with defective movement of cholesterol to other cellular membranes. Characterization of cell lines defective in intracellular cholesterol transport will facilitate identification of the gene(s) required for intracellular cholesterol movement and regulation.

Amphotericin B↗
PubMed1992

History of federal legislation for persons with disabilities.

This paper discusses federal legislation relating to persons with disabilities and it divides into 13 areas. Several areas of legislation, such as education and basic education, have a long history beginning with World War I. Laws related to other areas, such as federal support for developing technology, have been adopted only within the past 5 years. The Americans With Disabilities Act of 1990 (ADA) (Public Law 101-336), which guarantees civil rights to Americans with disabilities, has five titles, and each is summarized. Although the ADA provides for Americans with disabilities to be included in American society, it has some major limitations, including the lack of an affirmative action requirement and of provisions for the education and training of persons with disabilities so that they can qualify for employment. Several of the federal laws related to persons with disabilities have affected the field of occupational therapy either favorably or adversely. The conclusion is drawn that occupational therapists need to be alert to pending legislation to promote the role of occupational therapy in serving persons with disabilities.

Civil Rights↗
PubMed1991

The dimension of chaos in the fetal heart rate.

Variability in the fetal heart rate is known to be a sign of fetal well-being, and yet the origins of the variations remain unclear. This study incorporated the nonlinear analytic techniques of phase-space reconstruction and dimensional analysis to 12 normal heart rate tracings obtained from fetal scalp electrodes of fetuses in labor. Phase-space attractors were constructed with the method of time delays and showed characteristics consistent with those of nonlinear chaotic systems. Dimensional analysis resulted in three distinct groups being identified. Results indicate that control of the fetal heart rate may be modeled as a nonlinear or chaotic system, and analytic techniques borrowed from the physical sciences are useful in exploring heart rate variability. That different groups could be distinguished among qualitatively similar heart rate tracings may lead to understanding of discrepancies between evaluation of the monitor tracing and neonatal outcome.

Cardiotocography↗
PubMed1991

Doppler flow velocities in single umbilical arteries.

Fetal compromise has been associated with an umbilical artery waveform pattern of low or absent diastolic velocity relative to systolic velocity. Fetuses with single umbilical arteries have an increased risk of major malformations, mortality, retarded fetal growth, and prematurity. In this study Doppler flow velocities were obtained in 13 fetuses (four twin fetuses and nine singletons) with a single umbilical artery. Five (38%) fetuses, consisting of four singletons and one twin, had anomalies. Six (46%) fetuses were small for gestational age, including two twin fetuses and three singleton fetuses with anomalies. Three (23%) of the 13 systolic-to-diastolic velocity ratios were abnormally high. Whereas this is a higher rate of abnormal ratios than the reported 2% to 3% in control populations, it is interesting to note that 77% of fetuses with single umbilical arteries had normal systolic-to-diastolic ratios.

Abnormalities, Multiple↗
PubMed1991

Significance of oligohydramnios complicating pregnancy.

Oligohydramnios is a serious complication of pregnancy that is associated with a poor perinatal outcome. Eighty pregnancies complicated by oligohydramnios constitute the basis for this retrospective study. Forty patients had premature rupture of the membranes; of these, outcomes were good in 25. Twelve of 14 fetuses with oligohydramnios and intrauterine growth retardation survived. None of the nine fetuses with severe renal anomalies lived. None of the twins with twin-twin transfusion and oligohydramnios survived. Six pregnancies with oligohydramnios and premature separation of the placenta were identified; all of these resulted in fetal or neonatal death during the second trimester.

Blood Flow Velocity↗
PubMed1991

Tricuspid valve disease with significant tricuspid insufficiency in the fetus: diagnosis and outcome.

The echocardiographic studies and clinical course of 27 fetuses (mean gestational age 26.9 weeks) diagnosed in utero with tricuspid valve disease and significant tricuspid regurgitation were reviewed. The diagnosis of Ebstein's anomaly was made in 17 of the fetuses, 7 had tricuspid valve dysplasia with poorly developed but normally attached leaflets and 2 had an unguarded tricuspid valve orifice with little or no identifiable tricuspid tissue. One fetus was excluded from data analysis because a more complex heart lesion was documented at autopsy. All fetuses had massive right atrial dilation and most who were serially studied had progressive right-sided cardiomegaly. Hydrops fetalis was found in six cases and atrial flutter in five. Associated cardiac lesions included pulmonary stenosis in five cases and pulmonary atresia in six. Four fetuses with normal forward pulmonary artery flow at the initial examination were found at subsequent study to have retrograde pulmonary artery and ductal flow in association with the development of pulmonary stenosis (n = 1) and pulmonary atresia (n = 3). On review of the clinical course of the 23 fetuses (excluding 3 with elective abortion), 48% of the fetuses died in utero and 35% who were liveborn died despite vigorous medical and, when necessary, surgical management, many of whom had severe congestive heart failure. Of the four infants who survived the neonatal period, three had a benign neonatal course, all of whom were diagnosed with mild to moderate Ebstein's anomaly; only one had pulmonary outflow obstruction. An additional finding at autopsy was significant lung hypoplasia documented in 10 of 19 autopsy reports.(ABSTRACT TRUNCATED AT 250 WORDS)

Ebstein Anomaly↗
PubMed1991

Introduction to fetal echocardiography.

Fetal echocardiography is used to diagnose or exclude cardiac disease before birth. Fetuses known to be at risk for cardiac anomalies may be methodically screened; other fetuses present with abnormalities as pregnancy progresses and are studied as they are discovered. Abnormalities of anatomy as well as function may be detected. Anatomic abnormalities are often associated with additional noncardiac or chromosomal defects. Fetal cardiac disease may progress as gestation advances. Signs of deterioration include cardiac dilatation, increasing valvular insufficiency, and hydrops. Detection of fetal cardiac abnormalities allows the management team to better prepare for possible complications of labor and delivery and, in some cases, allows for treatment before birth.

Echocardiography↗
PubMed1991

Association of umbilical venous with inferior vena cava blood flow velocities.

The fetal cardiac and placental circulations are interconnected through the umbilical venous and arterial vasculature. We hypothesized that alterations in umbilical venous blood flow velocities are present in fetuses with abnormal umbilical arterial circulation, and further, that changes in inferior vena cava blood flow velocities occur with, and might explain, these variations in umbilical venous blood flow velocities. Umbilical venous and inferior vena cava blood flow velocities were examined in 15 normal fetuses and in 59 fetuses with abnormalities that included absent end-diastolic umbilical artery blood flow velocities (N = 21) or abnormal heart rates (N = 27). Inferior vena cava velocities were also analyzed in 11 other fetuses with anomalies or known growth or placental abnormalities who had abnormal umbilical venous blood flow velocities. In normal fetuses, variations in umbilical venous velocities occurred during fetal activity or with fetal breathing; however, no variation in velocity corresponded with heart rate. Eleven of 21 fetuses with absent end-diastolic velocities in the umbilical artery demonstrated decreases in umbilical venous velocities ("venous pulsations") during arterial diastole. Blood flow velocities in the reverse direction, from the right atrium into the inferior vena cava with atrial contraction, were significantly greater in these fetuses than in those without umbilical venous pulsations (27.5 +/- 14.9% and 7.5 +/- 5.7% of total forward flow velocity, respectively; P less than .001). Venous pulsations were also seen in fetuses with abnormally fast or slow heart rates; reverse flow with atrial contraction in the inferior vena cava was likewise greater than normal in these fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1990

Variation and correlation in human fetal umbilical Doppler velocities with fetal breathing: evidence of the cardiac-placental connection.

Doppler velocity waveforms in the human fetal umbilical vein and artery were analyzed during episodes of fetal breathing. Heart rate, systolic and diastolic velocities were measured from the umbilical artery waveform. Diastolic velocity varied the most with a mean (+/- SD) coefficient of variation of 16.0% +/- 5.0%. The coefficient of variation of systolic velocity was 7.8% +/- 2.4% and of heart rate was 5.0% +/- 1.8%. We also found that umbilical arterial flow was related to umbilical venous flow, implying an interdependence between fetal cardiovascular blood flow and placental blood flow. During breathing, venous flow varies because of changes in intrathoracic pressure in the fetus. This variation in umbilical venous velocity may affect the umbilical arterial diastolic velocity through alterations in placental filling, and may affect the umbilical arterial systolic velocity through alterations in ventricular filling, which by the Frank-Starling mechanism changes stroke volume. The interdependency of umbilical venous and umbilical arterial blood flow velocities must be considered in the interpretation of the significance of umbilical artery Doppler velocity measurements.

Blood Flow Velocity↗
PubMed1990

Doppler studies of vena cava flows in human fetuses. Insights into normal and abnormal cardiac physiology.

We examined vena cava Doppler flow velocity tracings from 69 fetuses between 22 and 40 weeks' gestation. Twenty-three fetuses had arrhythmias. Fifteen fetuses had absent end-diastolic Doppler velocities in the umbilical artery, a condition associated with intrauterine growth retardation, and 15 normal fetuses with normal umbilical artery Doppler velocity ratios were matched by gestational age. In studies in 16 additional fetuses, inferior vena cava Doppler velocity waveforms were compared with superior vena cava Doppler velocity waveforms. Peak velocities and time-velocity integrals of forward or reverse flow during systole, early diastole, and atrial contraction were measured. In addition, the time-velocity integral during flow coincident with atrial contraction (a wave) was expressed as a percent of the time-velocity integral of total forward flow during both systole and early diastole. Systolic-to-diastolic ratios of inferior vena cava forward time-velocity integrals were not significantly different from systolic-to-diastolic ratios of superior vena cava forward time-velocity integrals (p = 0.86), but the percent of blood moving in a reverse direction during atrial contraction in the inferior vena cava was greater than the percent of blood moving in a reverse direction in the superior vena cava (p less than 0.05). Relative forward flow in early diastole in the group of normal fetuses increased with advancing gestational age (r = 0.60, p less than 0.05). During premature atrial contractions flow in the inferior vena cava was reversed, and the percent of reverse flow during atrial systole increased significantly from 4.5 +/- 0.3% to 28.3 +/- 3.7% (mean +/- SEM, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1989

Fetal pericardial effusion.

Forty-four fetuses with pericardial effusions have been identified by ultrasonographic examinations. The clinical histories and courses of these patients were reviewed. At least eight different clinical features accompanied and were probably responsible for the pericardial effusions. The most common cause of a fetal pericardial effusion was heart failure (13 fetuses). Fetal renal cystic dysplasia with oligohydramnios and other anomalies was present in six fetuses. Four of this group had microscopic evidence of pericarditis on postmortem examination. Fetal pericardial effusions are always a manifestation of another disease process often presenting as fetal hydrops. Some pericardial effusions are transient. The etiologic origin of fetal pericardial effusions differs from that in the child or adult.

Female↗
PubMed1989

Human fetal tricuspid and mitral deceleration time: changes with normal pregnancy and intrauterine growth retardation.

Studies in instrumented adults have shown an association between Doppler echocardiography-derived atrioventricular valve deceleration times and ventricular function. To determine how gestational age affects deceleration time in the tricuspid and mitral valve, pulsed Doppler ultrasonographic examinations were performed in 54 normal human fetuses. In addition, 26 fetuses with growth retardation and the absence of end-diastolic Doppler velocities in the umbilical artery were examined. Measurements were obtained from strip chart recordings; between three and five beats were used to obtain an average heart rate, ratio of peak velocity at atrial contraction to peak velocity in early diastole, and deceleration time in early diastole. Deceleration times increased during gestation from 86 +/- 27 to 116 +/- 18 msec in the tricuspid valve and from 98 +/- 25 to 132 +/- 21 msec in the mitral valve. Fetuses with growth retardation and the absence of end-diastolic Doppler velocities in the umbilical artery had longer deceleration times than those of normal fetuses (p less than 0.01). The increase in deceleration time across both atrioventricular valves in normal fetuses may be related to heart rate, an increased rate of ventricular relaxation, or an increase in ventricular compliance. The fetuses with intrauterine growth retardation and the absence of end-diastolic velocities in the umbilical artery have abnormally increased deceleration times; in the abnormal fetus this may be a result of impaired ventricular relaxation or decreased ventricular compliance.

Blood Flow Velocity↗
PubMed1989

Fetal arrhythmias: etiology, diagnosis, pathophysiology, and treatment.

The study of arrhythmias enables the clinician not only to treat and effectively prevent some types of fetal morbidity, but also to understand the normal human fetal physiology. It can be anticipated that the study of arrhythmias in the fetus will expand, if the work currently performed in the child and adult is any indication.

Arrhythmias, Cardiac↗