Search PubMed⌕ Search

Biomedical subjects

C F Anderson

Publications and source records attributed to C F Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Prenatal diagnosis of congestive heart failure in a fetus with a sacrococcygeal teratoma.

Two-dimensional Doppler echocardiography was used to diagnose congestive heart failure in a fetus with a large sacrococcygeal teratoma. Ultrasound performed for size-date inconsistency revealed a 27.5-week fetus with hydrops and a large solid and cystic mass in the sacral region. Fetal echocardiography showed dilated ventricles and a pericardial effusion; Doppler ultrasound demonstrated increased velocities and volume flows, along with tricuspid and mitral regurgitation. At delivery, the mass was bleeding actively, the amniotic fluid was markedly bloody, and the neonatal hematocrit was 10%. We postulate that intrauterine hemorrhage from the teratoma led to anemia and high-output cardiac failure confirmed by Doppler echocardiography, and suggest that all fetuses with sacrococcygeal teratomas be evaluated by two-dimensional Doppler echocardiography to detect the presence of congestive heart failure, in order to allow well-timed therapeutic interventions.

Adult↗
PubMed1987

Competitive interactions of Co(NH3)6(3+) and Na+ with helical B-DNA probed by 59Co and 23Na NMR.

59Co NMR is demonstrated to provide a useful probe of the interactions of Co(NH3)6(3+) with helical B-DNA. The association of Co(NH3)6(3+) with B-DNA produces relatively modest effects on the relaxation rate and chemical shift of 59Co, which indicate that the octahedral coordination shell remains intact and that no significant number of long-lived "outer-sphere" complexes are formed at specific sites on the DNA surface. Under conditions where essentially all of the cobalt complex is associated with DNA, the chemical shift of 59Co appears to depend on its binding density. This effect could be due to magnetic heterogeneity in the environments of Co(NH3)6(3+) adjacent to DNA. The local exchange reaction between Co(NH3)6(3+) and Na+ in the vicinity of DNA has been investigated by measuring 59Co chemical shifts and 23Na line widths concurrently. The number of sodium ions displaced by the association of one Co(NH3)6(3+) with DNA cannot be uniquely determined, but the data indicate that this number remains constant over at least the initial stage of a titration of NaDNA with NaCl. 59Co chemical shifts have been analyzed to construct binding isotherms for the association of cobalt hexaammine with DNA over a range of salt (NaCl) concentrations. The magnitudes of the resulting binding constants and their salt dependence are similar to those previously reported for the association of structurally diverse trivalent ligands, such as spermidine and trilysine, with helical nucleic acids. Therefore, these association equilibria appear to be governed primarily by electrostatic interactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cobalt↗
PubMed1987

Variability of the intracellular ionic environment of Escherichia coli. Differences between in vitro and in vivo effects of ion concentrations on protein-DNA interactions and gene expression.

Effects of changes in intracellular ion concentrations on the interactions of Escherichia coli lac repressor with lac operator mutants and on the interactions of RNA polymerase with various promoters have been investigated in vivo. The intracellular ionic environment was reproducibly varied by changing the osmolality of the 4-morpholinepropanesulfonic acid minimal growth medium. As the osmolality of the growth medium is varied from 0.1 to 1.1 osmolal, the total intracellular concentration of K+ increases linearly from 0.23 +/- 0.03 to 0.93 +/- 0.05 molal and the total intracellular concentration of glutamate increases linearly from 0.03 +/- 0.01 to 0.26 +/- 0.02 molal. The sum of the changes in the total concentrations of these two ions appears sufficient to compensate for a given change in external osmolality, indicating that K+ and glutamate are the primary ionic osmolytes under these conditions and that these ions are free in the cytoplasm. In support of this, in vivo 39K NMR experiments as a function of external osmolality indicate that changes in the total cytoplasmic K+ concentration correspond to changes in the free cytoplasmic K+ concentration. Extents of interaction of lac repressor and RNA polymerase with their specific DNA sites were monitored by measuring the amounts of beta-galactosidase produced under the control of these sites. For both lac repressor and RNA polymerase, it was found that formation of functional protein-DNA complexes in vivo is only weakly (if at all) dependent on intracellular ion concentration. These results contrast strongly with those obtained on these systems in vitro, which showed that both the equilibria and kinetics of binding are extremely salt-dependent. We discuss several possible mechanisms by which E. coli may compensate for the potentially disruptive effects of these large changes in the intracellular ionic environment.

Amino Acids↗
PubMed1987

Changes in intracardiac Doppler blood flow velocities in fetuses with absent umbilical artery diastolic flow.

Umbilical artery Doppler blood flow velocity studies were used to identify 14 fetuses with absent flow during diastole to determine the significance of absent umbilical artery diastolic flow. Outcomes of these fetuses were recorded, and the associated intracardiac Doppler changes were identified in 12 of them. Maximal and mean intracardiac flow velocities were measured, and volume flows through the right (tricuspid valve, pulmonary valve) and left (mitral valve, aortic valve) sides of the heart were compared. Ratios of intracardiac peak flow velocity in late diastole to peak flow velocity in early diastole were calculated. Eleven fetuses had intrauterine growth retardation, and four had multiple congenital anomalies. Fetuses with no diastolic flow in the umbilical artery had increased volume flow across the tricuspid and pulmonary valves compared with normal fetuses of similar weights. The ratio of right-sided to left-sided volume flow in the heart (2.15:1) was increased compared with values in normal fetuses (1.33:1, p less than 0.01). The ratio of late diastolic to early diastolic peak flow velocities across the mitral valve was decreased (p less than 0.01). Absent umbilical artery diastolic flow is associated with increased tricuspid and pulmonary valve volume flow and changes in mitral flow velocity patterns, which suggests that there are alterations in left ventricular function.

Abnormalities, Multiple↗
PubMed1987

Congenital heart block and cardiac anomalies in the absence of maternal connective tissue disease.

The association of congenital heart block with maternal connective tissue disease and autoimmunity has been recently reported. Two cases of heart block were diagnosed in utero at 23 and 24 weeks' gestation. Both mothers had extensive workups for connective tissue disease that were negative. Two-dimensional and Doppler echocardiography were performed in utero and both infants had left atrial isomerism, atrioventricular canal defects, and severe hydrops in addition to heart block. Review of the recent literature identifies a subset of congenital heart block in which the mothers have no evidence for connective tissue disease, and the fetus or neonate has complex cardiac malformations and hydrops. The common features in these babies are atrioventricular canal defects and isomerism. No reports of congenital heart disease among the children of mothers with connective tissue disease fit this description. Our recent experience and literature review emphasize the previously known association between congenital heart block and congenital heart disease. This association is especially important in light of the poor prognosis for this group of fetuses and neonates.

Adolescent↗
PubMed1987

Blood pressure determinants in living-related renal allograft donors and their recipients.

We studied 99 living related allograft donors with follow-up information of at least 10 years and the 50 recipients who had successful outcomes. Recipients were younger and had significantly lower blood pressures at follow-up than their donors. Borderline and definite hypertension were present in 22.2% and 4.0% of donors prior to donation, in 14.4% and 21.1% of donors at follow-up, and in 2.0% and 18.0% of the 50 recipients at follow-up. Age, relative weight, and mean arterial pressure (MAP) prior to donation were the key variables in predicting the follow-up ranked MAP of the donors. CPAH prior to donation was inversely correlated with the age of the donors and, indirectly, with the follow-up MAP. Donor CPAH prior to donation was significantly correlated with the renal allograft function of the recipients but not with the recipient ranked MAP at follow-up. No correlation of the ranked MAP or blood pressure outcome categories between donors and recipients was found. We conclude that donation of one kidney can accelerate the development of hypertension in those donors with predisposition to develop hypertension. In addition, the predisposition of the donors to develop hypertension and their age, within the range observed in the study, does not significantly influence the long-term blood pressure status of the recipient.

Adult↗
PubMed1987

Cardiac Doppler flows during fetal arrhythmias: physiologic consequences.

Eighty-six fetuses of 21-41 weeks' gestation with arrhythmias were studied with ultrasound and heart rate monitoring. The type of arrhythmia was identified by M-mode studies and was confirmed by postnatal electrocardiogram in 70 infants. The most common arrhythmia was premature atrial contractions (76), followed by premature ventricular contractions (five), paroxysmal supraventricular tachycardia (four), and atrial fibrillation/flutter (one). Doppler echocardiography was performed in 54 fetuses to measure flow velocities across the atrioventricular and semilunar valves. After isolated premature atrial and ventricular contractions, post-extrasystolic potentiation was demonstrated by an increase in fractional shortening (N = 32) of 49 +/- 6% in the right ventricle and 64 +/- 7% in the left ventricle. When post-extrasystolic beats were compared with normal beats, Doppler-determined time-velocity integrals increased 43% across the tricuspid valve, 41% across the mitral valve, 34% across the pulmonary valve, and 38% across the aortic valve. Mean velocity increased significantly after conversion to normal sinus rhythm in the five fetuses with supraventricular tachycardia (P less than .05). By studying the physiologic consequences of fetal arrhythmias using two-dimensional Doppler and M-mode ultrasound, we have documented the presence of post-extrasystolic potentiation after premature contractions, the existence of the Frank-Starling mechanism, and an increase in mean velocity (and therefore in cardiac output) after conversion of fetal tachyarrhythmias to normal sinus rhythm.

Arrhythmias, Cardiac↗
PubMed1987

Fetal pulmonary artery and aorta: two-dimensional Doppler echocardiography.

Two-dimensional and pulsed Doppler ultrasound techniques were used to examine 87 fetuses between 17 and 41 weeks' gestation in order to compare pulmonary artery and aortic outflow diameters, mean and maximal flow velocities, and transvalve flows. For purposes of analysis, fetuses were divided into two groups: those less than 31 weeks, and those of 31 weeks or more. Diameters of the pulmonary artery and aortic outflow region increased with advancing gestational age (P less than .001), while mean and maximal Doppler flow velocities did not change. Transvalve volume flow increased across both regions (pulmonary artery from 381 +/- 12 mL/minute to 530 +/- 13 mL/minute and aortic outflow from 286 +/- 10 mL/minute to 410 +/- 13 mL/minute, P less than .001) with advancing gestation. Pulmonary artery diameters were larger than aortic outflow diameters in both groups (P less than .01), while mean Doppler flow velocities were not significantly different. Maximal Doppler flow velocities were greater in the aorta than in the pulmonary artery (P less than .001), and transvalve flow was greater across the pulmonary artery than the aorta in both groups (P less than .05, ratio 1.3:1). This work demonstrates differences in fetal pulmonary artery and aortic outflow anatomy and physiology that must be considered in evaluating studies of fetal cardiac physiology.

Aorta↗
PubMed1986

Limitations of nutritional assessment in predicting the outcome of colorectal operations.

The value of preoperative nutritional assessment in predicting postoperative morbidity and mortality is controversial. To evaluate the predictive value of preoperative nutritional status, the courses of 100 consecutive patients undergoing colorectal operations were studied prospectively. Subnormal findings for triceps-skin-fold thickness (TSF) and percentage of ideal body weight were associated with a significantly higher complication rate, but occurred so infrequently in our patients that the routine use of these tests is not recommended. Subnormal values for commonly obtained nutritional variables may not justify delay of operation for nutritional repletion.

Adolescent↗
PubMed1986

Nutrient intake in critically ill patients: too many or too few calories?

We studied the relationship of caloric needs and total caloric intake in a series of 61 critically ill patients in an intensive care unit. All patients were receiving only central parenteral nutrition. On the basis of the ratio of total caloric intake to resting energy expenditure (REE), the nonprotein respiratory quotient (npRQ), and, when appropriate, Lusk's table for analysis of the oxidation of mixtures of carbohydrate and fat, the patients could be categorized into three groups. The group with inadequate caloric intake had a ratio of total calories to REE of less than 1.0. The group with net lipolysis had a ratio of caloric intake to REE of 1.0 or more and npRQ values of less than 1.0. The group with net lipogenesis had a ratio of caloric intake to REE of 1.0 or more and either npRQ values or equivalent npRQ values of 1.0 or more. Equivalent npRQ values in patients who were receiving amino acids, dextrose, and lipids were determined by using Lusk's table and the percentage of total caloric intake as fat.

Basal Metabolism↗
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↗
PubMed1985

Ions as regulators of protein-nucleic acid interactions in vitro and in vivo.

The key feature of the kinetics and equilibria of both specific and non-specific noncovalent interactions of proteins with nucleic acids is their sensitivity to the details of the ionic environment. Investigation of the effects of ion concentrations provides detailed and otherwise unobtainable information about the thermodynamics and mechanisms of these interactions. We discuss the molecular and thermodynamic basis of the contribution to these ion effects from electrolyte-nucleic acid interactions, and demonstrate that a simple ion exchange formalism, involving the stoichiometric participation of individual ions, is the appropriate basis for interpreting these profound effects at a thermodynamic level. Since the in vivo ionic environment is both complex and variable, we propose that variations in intracellular concentrations of individual ions play both global and specific roles in the control of the protein-nucleic acid interactions responsible for nucleoprotein structure and gene expression.

DNA, Bacterial↗
PubMed1985

The risks of unilateral nephrectomy: status of kidney donors 10 to 20 years postoperatively.

We received requested follow-up information from 105 (73%) of our 144 kidney donors who had undergone unilateral nephrectomy 10 to 20 years previously. Five donors had died of unrelated causes 6 or more years postoperatively. Studies in the remaining 100 donors showed that the current mean serum creatinine concentration was 1.2 mg/dl and the mean 24-hour urinary protein value was 89 mg. Hypertension (defined as 160 mm Hg or more systolic, 95 mm Hg or more diastolic, or both) was present in 19% of the donors. In a subgroup of 66 donors who had had serial serum creatinine determinations, the renal function, as estimated on the basis of these serum creatinine values, had not deteriorated with time. Thus, we consider unilateral nephrectomy in this group of patients relatively safe. Subsequent evaluation will be necessary to ascertain whether these findings prevail.

Adolescent↗
PubMed1984

23Na NMR relaxation study of the effects of conformation and base composition on the interactions of counterions with double-helical DNA.

NMR relaxation rates (T1(-1) and T2(-1)) have been determined for 23Na in aqueous salt solutions containing various types of helical double-stranded deoxyribonucleic acids. These measurements were performed on three synthetic polynucleotides having different overall conformations, poly-(dA-dT).poly(dA-dT) (alternating B-DNA), poly(dG-dC).poly(dG-dC) at low salt (B-DNA), and Br-poly(dG-dC).Br-poly(dG-dC) (left-handed Z-DNA), and on four types of natural DNA differing in base composition, Clostridium perfringens (26% GC), calf thymus (40% GC), Escherichia coli (50% GC), and Micrococcus lysodeikticus (72% GC). For all types of DNA investigated, except poly(dA-dT).poly(dA-dT), the 23Na NMR spectra measured at 21 degrees C and an applied field of 4.7 T are non-Lorentzian. These non-Lorentzian spectra were analyzed on the basis of the two-state model and the standard theory of nonexponential quadrupolar relaxation processes in order to obtain estimates of the correlation times (tau c) characteristic of the sodium nuclei associated with the various nucleic acids. All of the correlation times estimated in this way are in the range of nanoseconds. The magnitudes of these correlation times show a significant dependence on the overall conformation of the nucleic acid (B vs. Z) but not on its base composition. To investigate the concentration dependence of tau c, sodium or magnesium salts were added to solutions of Br-poly(dG-dC).Br-poly(dG-dC) (Z-DNA).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Membranoproliferative glomerulonephritis. A prospective clinical trial of platelet-inhibitor therapy.

Forty patients with Type I membranoproliferative glomerulonephritis were treated for one year with dipyridamole, 225 mg per day, and aspirin, 975 mg per day, in a prospective, randomized, double-blind, placebo-controlled study. At the base line, the half-life of 51Cr-labeled platelets was reduced in 12 of 17 patients. The platelet half-life became longer and renal function stabilized in the treated group, as compared with the placebo group, suggesting a relation between platelet consumption and the glomerulopathy. The glomerular filtration rate, determined by iothalamate clearance, was better maintained in the treated group (average decrease, 1.3 ml per minute per 1.73 m2 of body-surface area per 12 months) than in the placebo group (average decrease, 19.6). Fewer patients in the treated group than in the placebo group had progression to end-stage renal disease (3 of 21 after 62 months as compared with 9 of 19 after 33 months). The data suggest that dipyridamole and aspirin slowed the deterioration of renal function and the development of end-stage renal disease.

Adolescent↗
PubMed1984

The sensitivity and specificity of nutrition-related variables in relationship to the duration of hospital stay and the rate of complications.

We assessed the nutritional status at the time of hospital admission of 74 patients who were admitted for elective gynecologic or urologic operations. Nutritional assessment included measurement of serum albumin, thyroxine-binding prealbumin, retinol-binding protein, weight-change history, estimate of daily protein and total calorie intake, and a global estimate of nutritional risk. The sensitivity, specificity, false-positive rate, likelihood ratio, and positive predictive value of these nutrition-related variables were analyzed in patients who stayed in the hospital for longer than 10 days and in those patients with recognized complications. In the analysis of patients who remained in the hospital longer than 10 days, the finding of a low serum protein concentration or a low protein intake was most sensitive, and a low serum albumin concentration was the most specific. A receiver-operating-characteristic diagram that depicts the sensitivity and false-positive rates for the single variables and the combinations of variables is probably the most clinically useful summary of our study. Using the information in such a diagram, a clinician might choose variables that are more sensitive to identify hospitalized patients who should receive special nutritional attention in comparison with another clinician who might need fewer false-positive results for a prospective study of nutritional intervention.

Adult↗