High incidences of cleft lip and palate (CLP) produced by maternal intraperitoneal administration of 75 mg/kg phenytoin on gestational day 10 to A/J mice are associated with a severe size reduction in the lateral nasal process. Scanning and transmission EM analyses of this region demonstrate a marked change in the morphology of the mesenchymal cells underlying the surface epithelium in treated versus control day 11 (7-tail somite) embryos: long, branching cellular processes, which form a dense meshwork that appears to interact with the epithelial basement lamina in control embryos are undeveloped or absent in phenytoin-treated embryos. The ultrastructural morphology of these cell processes is described and their possible importance in normal development is discussed. Scanning EM observations of incomplete clefts of the lip which frequently result from phenytoin treatment indicate that Simonart's bands form from fusion of the lateral and medial nasal processes in association with a lack of fusion of the maxillary process with the medial nasal process.
Useful information derived from BAER waveforms include: a) presence or absence of waveform components, b) latency, and c) latency intervals between components (especially Waves I, 111, and V). BAER analyses using click intensities 75dB above adult thresholds recorded ipsilaterally were obtained from 41 neonates (a30 weeks' gestation) suspected of hypoxic brain injury. Also, an ultrasound scan was done near the time BAER tests were performed. Of 14 infants who showed absence of a reliable waveform, 12 had evidence of brain hemorrhage by ultrasound. In 27 infants, Waves I, 111, and V were reliably detected. A linear discriminant function based on Wave I latency and the 111-V latency interval was constructed that reliably predicted 85% (23) of the sonographic results. Thus, we found BAER analyses to be highly concordant with sonography (x2 = 20.5, E <0.001). Birthweight and gestational age did not significantly enter into the discriminant equation. Return of the BAER response toward normal followed resolution of the hemorrhage observed by ultrasound. These data indicate that acute structural brain damage due to hemorrhage is associated frequently with acute functional abnormalities measured by BAER; both appear to resolve together. However, the importance of these findings to predict further chronic neurologic abnormalities remains to be determined. In a prospective study of factors which may predict neurologic outcome in VLBW infants, complete observations were collected on 84 preterm infants of < 32 weeks gestation. Cranial ultrasound (US.) was performed on days 1 and 3. The studies on day 3 better predicted outcome and will be described.US. were scored as "Normal" (normal, suspect, or mild ICH) or "Severe" (IVH with dilated ventricles or parenchymal blood). US. scores were compared with: neurologic status in the first week, occurence of seizures, development of hydrocephalus, discharge neurologic status, and mortality.Mean B.Wt. was 1229 gm, and mean GA was 30.3 weeks. 73 infants had "Normal" US., and 11 had "Severe" US. "Severe" US. correlated with low B.Wt. (p<.01), and low 5 minute Apgar score (ph.005), but not with GA or 1 minute Apgar score.US. did not correlate with development of hydrocephalus, or abnormal discharge neurologic status. The following outcomes correlated wi long-term neurologic outcome. Detection of BAER waveforms in the neonatal ICU is hampered by the large size of the typical "pediatric earphone" normally used (TDH-39). ULTRA-LIGHT EARPHONESEarphone size prevents adequate stability of sound intensity under all ICU conditions without disrupting or handling the infant during a BAER test. Also, large speaker coils must operate at higher currents; this induces stimulus artifacts which distort the cochlear microphonic and the auditory nerve response components (CM and Wave I). This is especially true at the intensities needed to test infants. We found that essentially the same BAER waveform, without significant stimulus artifacts, is produced using miniture ultra-lightweight earphones made with...
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