Biomedical subjects

Todd Schwartz

Publications and source records attributed to Todd Schwartz.

6 recordsLinked to original sources

PubMed2006

Effects of antenatal magnesium sulfate and corticosteroid therapy on sleep states of preterm infants.

This exploratory longitudinal study was designed to compare the neonatal illness severity, sleep-wake, and respiratory sleep behaviors of preterm infants whose mothers received prenatal corticosteroids and/or magnesium sulfate (MgSO4) with those of infants whose mothers did not receive these medications. The 134 infants were divided into four groups: those whose mothers received MgSO4 only, those who received steroids only, those who received both MgSO4 and steroids, and those who received neither. The groups did not differ on infant characteristics or illness severity. Infants exposed to MgSO4 had more active sleep without rapid eye movement, indicating poorly organized active sleep. The MgSO4 -only group had higher quiet sleep regularity scores and fewer state changes. These findings suggest that fetal exposure to MgSO4 may subtly affect the central nervous system.

Adrenal Cortex Hormones↗

PubMed2004

Sleeping and waking state development in preterm infants.

BACKGROUND: Most studies of sleep-wake states of preterm infants have been cross-sectional. Thus, the extent to which sleep-wake development occurs within individuals and how environmental factors affect the development of sleeping and waking is unclear. AIMS: This study examined the development of sleeping and waking during the preterm and early post-term periods and the effects of infant health and environmental characteristics. DESIGN: Longitudinal, descriptive design. PARTICIPANTS: 134 preterm infants at high risk for developmental problems because of birthweights under 1500 g or mechanical ventilation. OUTCOME MEASURES: Weekly 2-h behavioral observations were conducted from the time infants were no longer critically ill until 43 weeks post-conceptional age or discharge. A single follow-up observation was conducted 1-3 months later. RESULTS: Active sleep, large body movements and the percent of no REM during active sleep decreased with age, and quiet waking, active waking, quiet sleep and regularity of respiration in active sleep and quiet sleep increased. The state of sleep-wake transition increased until 40 weeks and then decreased after 43 weeks CA. Negative facial expressions showed a quadratic decrease over age. Active waking, active sleep, negative facial expressions and quiet sleep regularity showed a change of development after term. Infant characteristics, illness severity and medical treatments, the handling due to performing an EEG and hospital had only minor effects. CONCLUSIONS: Significant development of sleeping and waking occurs over the preterm period. Additional research is needed to determine how the change from the hospital to the home environment affects on these developmental trajectories.

Female↗

PubMed2004

Respiratory development in preterm infants.

OBJECTIVE: This study examined the development of respiration during the preterm and early post-term periods and the effects of other biological and environmental variables, including sleep state, on this development. STUDY DESIGN: Weekly 2-hour sleep observations and respiration recordings were obtained on 134 preterm infants from the time they were no longer critical until hospital discharge; a follow-up observation was conducted 1 to 3 months later. RESULTS: All respiratory variables, except length of respiratory pauses in quiet sleep, decreased although the rate of this decrease slowed after term for four variables. Respiratory variables, except variability of respiratory pauses lengths and periodic respiration, differed by sleep state. Covariates, except methylxanthine treatment, had minor effects. Four variables showed hospital-related differences, but cisapride treatment helped to explain the differences in three variables. CONCLUSIONS: Much development of respiration occurs in the early weeks after birth and reflects both neural maturation and effects of other biological and environmental factors, especially medications.

Child Development↗

PubMed2003

Effects of hyperfibrinogenemia on vasculature of C57BL/6 mice with and without atherogenic diet.

OBJECTIVE: Elevated fibrinogen is correlated with severe atherosclerosis, as defined by the occurrence of ischemic events, but the mechanistic basis for this correlation remains unknown. To study this relationship, we examined spontaneous and diet-induced atherosclerosis in transgenic mice with hyperfibrinogenemia (elevated fibrinogen). METHODS AND RESULTS: Normal and transgenic mice were fed either an atherogenic diet or simple breeder chow. We measured plasma fibrinogen levels and identified an age-dependent and diet-dependent increase in fibrinogen. After 8 to 12 months, aortic sections were prepared and stained, and lipid-containing lesions were counted, measured, and assessed for maturity. Lipid-filled deposits appeared spontaneously in a small number of mice on breeder chow; typical fatty streak-type lesions appeared in almost all of the diet-fed animals. Morphometric analysis showed that neither the number nor the size of lesions was influenced by either fibrinogen level or genotype. CONCLUSIONS: Our data showed that neither fibrinogen concentration nor genotype had a statistically significant effect on the initiation, initial growth, or early progression of atherosclerotic lesions.

Animals↗

PubMed2002

Echocardiographic predictors of adverse outcomes in primary pulmonary hypertension.

OBJECTIVES: The aim of this study was to evaluate the relationships between echocardiographic findings and clinical outcomes in patients with severe primary pulmonary hypertension (PPH). BACKGROUND: Primary pulmonary hypertension is associated with abnormalities of right heart structure and function that contribute to the poor prognosis of the disease. Echocardiographic abnormalities associated with PPH have been described, but the prognostic significance of these findings remains poorly characterized. METHODS: Echocardiographic studies, invasive hemodynamic measurements and 6-min walk tests were performed and outcomes prospectively followed in 81 patients with severe PPH. Subjects were participants in a 12-week randomized trial examining the effects of prostacyclin plus conventional therapy compared with conventional therapy alone. RESULTS: During the mean follow-up period of 36.9 +/- 15.4 months, 20 patients died and 21 patients underwent transplantation. Pericardial effusion (p = 0.003) and indexed right atrial area (p = 0.005) were predictors of mortality. Pericardial effusion (p = 0.017), indexed right atrial area (p = 0.012) and the degree of septal shift in diastole (p = 0.004) were predictors of a composite end point of death or transplantation. In multivariable analyses incorporating clinical, hemodynamic and echocardiographic variables, pericardial effusion and an enlarged right atrium remained predictors of adverse outcomes. Six-minute walk results, mixed venous oxygen saturation and initial treatment randomization were also independently associated with a poor prognosis. CONCLUSIONS: Pericardial effusion, right atrial enlargement and septal displacement are echocardiographic abnormalities that reflect the severity of right heart failure and predict adverse outcomes in patients with severe PPH. These characteristics may help identify patients appropriate for more intensive medical therapy or earlier transplantation.

Adult↗

PubMedDate not supplied

Development of behaviors in preterm infants: relation to sleeping and waking.

BACKGROUND: Although nurse clinicians and researchers use infant behaviors to indicate the responses of preterm infant to stimulation, little is known about how the biological factors of development, sleeping and waking states, infant characteristics, and infant illness severity affect preterm infant behaviors. OBJECTIVE: This study examined the development of eight infant behaviors over the preterm period and determined the relation of these behaviors to sleeping and waking and to infant characteristics and illness severity. METHODS: Seventy-one preterm infants were observed once per week from 7:00 p.m. to 11:00 p.m. from the time they were no longer critical until term or discharge. The occurrence of four sleep-wake states and eight behaviors were recorded every 10 seconds during the observations. RESULTS: Negative facial expressions increased over the preterm period; sighs, startle/jerks, jitters, and the likelihood of having hiccups decreased. Infant characteristics had only minor effects: boys had more negative facial expressions, and longer mechanical ventilation was associated with more sighs and jitters. All behaviors showed state-related differences in frequency. In addition, only startle/jerks and jitters showed the same developmental patterns within each state. CONCLUSIONS: Significant development of infant behaviors occurs over the preterm period but involves changes not only in the absolute percentage of each behavior but also in the percentages within each sleeping and waking state. Thus, preterm infant behaviors cannot be used clinically for assessment without consideration of the state in which they occur.

Activity Cycles↗