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B Z Karmel

Publications and source records attributed to B Z Karmel.

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Differences in salivary cortisol levels in cocaine-exposed and noncocaine-exposed NICU infants.

To assess whether cocaine exposure in utero affected adrenocortical responsiveness in the neonatal period, salivary cortisol levels were compared between noncocaine-exposed (n = 35) and cocaine-exposed (n = 11) healthy preterm infants just prior to hospital discharge. Cortisol levels were measured under three conditions: Basal--120 min after no disrupting event or behavioral distress; Noninvasive Stressor--30 min after a neurobehavioral examination; Invasive Stressor--30 min after a heel-stick procedure. There were no differences in Basal cortisol levels between the noncocaine-exposed and cocaine-exposed infants, but the cocaine-exposed infants had significantly lower levels in both the Noninvasive and Invasive Stressor conditions. The suppressed cortisol responding to stressful events in cocaine-exposed infants suggests that these infants may have decreased modulation capability to normally stressful events, which could underlie some of the subtle state regulation problems reported.

Adrenal Cortex

The relationship of maternal erythrocyte oxygen transport parameters to intrauterine growth retardation.

The relation of fetal growth and maternal oxygen transport as assessed by red blood cell 2,3-diphosphoglycerate, hemoglobin oxygen affinity, hemoglobin, pH, and PCO2 was evaluated in 21 pregnant women. The study was performed in the third trimester and each subject evaluated had sonographic evidence of fetal growth retardation without other obvious abnormalities. Decreased maternal 2,3-diphosphoglycerate/hemoglobin molar ratio and hemoglobin oxygen affinity were related linearly to the birth weight normalized for the expected sea level values of gestational age expressed as a birth weight (gestational age-normalized) Z score. The correlation coefficients and p values were r = 0.71, p less than 0.001 and r = 0.67, p less than 0.001, respectively. The ponderal index-normalized Z score correlated with the 2,3-diphosphoglycerate/hemoglobin molar ratio (r = 0.46, p less than 0.04), but the relation was not as strong as the birth weight-normalized Z score. The crown-heel length/head circumference ratio did not correlate with the 2,3-diphosphoglycerate/hemoglobin molar ratio (r = 0.29, NS). The birth weight (gestational age)-normalized Z score did not correlate with hemoglobin, PCO2, or pH. In the regulation of hemoglobin oxygen affinity, calculations indicated that the 2,3-diphosphoglycerate/hemoglobin molar ratio played a highly significant role (p less than 0.001), pH was minimally significant (p less than 0.025), but PCO2 had little or no significant effects in this study. It appears that fetal growth is related to the maternal red blood cell oxygen transport parameters 2,3-diphosphoglycerate/hemoglobin molar ratio and hemoglobin oxygen affinity. Moreover, the 2,3-diphosphoglycerate/hemoglobin molar ratio is the principal regulator of hemoglobin oxygen affinity.

2,3-Diphosphoglycerate

Neurometrics.

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Brain-stem auditory evoked responses as indicators of early brain insult.

The relationship between cranial ultrasonograms (SONOs) and brain-stem auditory evoked responses (BAERs) was evaluated in 2 independent samples of newborn infants at risk for brain injury (n = 113 and 203). Features of the BAER wave forms subjected to stepwise linear discriminant analysis formed the basis of an algorithm used to detect and follow early brain injury. Using this algorithm, information derived from BAERs reliably predicted SONO abnormalities at least 82.3% of the time in the initial study which was replicated with the second sample (77.3%). The wave I component latency (CL) and the wave III-V inter-peak latency interval (IPL) were independent of each other, and both contributed to a prediction of SONO abnormality. Possible mechanisms for these BAER results include compromise to the cochlear membrane or to the auditory nerve itself as well as prolongation of transmission in the brain-stem due to brain-stem hemorrhage, edema, or compression. Normative BAER values and non-linear regression functions for the wave I, III and V CLs, and the I-III, III-V, and I-V IPLs were calculated across age using data from 109 infants who demonstrated normal BAER patterns and had no history of SONO abnormalities. Our analyses indicate BAER techniques, where a single higher intensity is used to produce the BAER wave form, are both valid and efficient for use in the evaluation of early brain injury.

Brain Injuries