Lap-sash three point seat belt fractures of the cervical spine

Cervical spine injuries associated with three-point fixation lap-sash seat belts result from impact against the sash. While such injuries are infrequent and often without serious neurologic sequelae, they may produce serious deficits with grave injuries. Flexion-extension fractures of the lower cervical vertebrae, fractures of the transverse and spinous processes of the lower cervical and uppermost thoracic vertebrae, discal disruptions, and brachial plexus avulsions may occur. Of the 3 patients reported here, 2 escaped serious damage.

Regulation of cerebral blood flow in the ovine fetus

The effects on fetal cerebral blood flow (Qc) of changes in the carotid arterial and sagittal sinus venous PO2, PCO2, and oxygen content were studied in the chronically catheterized ovine fetus in utero at 130-140 days of gestation. Forty-seven measurements of Qc were made in 20 fetuses with radioactive microspheres. In 11 of these animals, 84 measurements of cerebral arteriovenous differences of oxygen content were performed, permitting an indirect measurement of cerebral blood flow (Qc*), assuming a constant cerebral metabolic rate. Arterial and, in 11 animals, sagittal sinus blood was withdrawn for analysis of PO2, PCO2, oxygen content, and pH at the time of the flow measurements. Preliminary analysis showed the best predictor of Qc and Qc* to be the reciprocal of the arterial oxygen content (1/CaO2). Multiple linear regression analysis combining the effects of 1/CaO2 with arterial PCO2 (PaCO2) gave the following equations: Qc = 458.8 (1/CaO2) + 2.68 PaCO2 - 107.93 (R2 = 0.68); Qc* = 435.54 (1CaO2) + 2.20 PaCO2 - 75.03 (R2 = 0.86). As a result of the hyperbolic relationship between Qc (and Qc*) and CaO2, changes in CaO2 at the low levels found during intrauterine life exert an important influence on the fetal cerebral circulation.

Right-sided congenital diaphragmatic herniae presenting as pleural effusions in the newborn: dangers and pitfalls

Congenital diaphragmatic hernia presented with right-sided pleural effusion in two newborn infants.

Insulin effect on fetal glucose utilization

Insulin infused into a sheep fetus over a 3-hr period at the rate of approximately 0.24 U.kg-1.h-1 increased fetal glucose uptake (utilization) from 4.4 +/- 0.7 mg.min-1.kg-1 to 6.9 +/- 0.9 mg.min-1.kg-1 as compared to a noninsulin control period. Insulin administration did not alter fetal oxygen consumption (8.6 +/- 0.7 ml.min-1.kg-1 vs. 7.7 +/- 0.7 ml.min-1.kg-1), umbilical blood flow (220 +/- 1 ml.min-1.kg-1 vs. 209 +/- 16 ml.min-1.kg-1), or the placental clearances of antipyrine (114 +/- 7 ml.min-1.kg-1 vs. 109 +/- 8ml.min-1.kg-1) and urea (24.5 +/- 2.2 ml.min-1.kg-1 vs. 25.0 +/- 2.1 ml.min-1.kg-1). Fetal plasma glucose concentration fell significantly (0.22 +/- 0.01 mg.ml-1 to 0.16 +/- 0.01 mg.ml-1) during insulin infusion. The insulin effect on fetal glucose uptake occurred over a range of maternal glucose concentrations (0.32 leads to 0.78 mg.ml-1), which were not altered by the infusion of insulin in the fetal compartment. Insulin has a specific effect on increasing fetal glucose uptake and utilization.

The effect of cuff width on systolic blood pressure measurements in neonates

The width of the blood pressure cuff was found to have an effect on the accuracy of systolic blood pressure measured in the arm and thigh in neonates. Data were collected in 26 infants of a variety of birth weights and gestational ages. They show that the effect of cuff size can be minimized by selecting a cuff width equal to approximately 50% of the extremity circumference.

Lumbar spinal stenosis

Recognition and management of problems inherent in spinal stenosis require a clear understanding of the diverse anatomic changes, their radiologic representations, and careful correlation with a wide spectrum of fluctuating clinical manifestations. Although a common basis might be postulated for narrowing of the spinal canal, emphasis should be placed on its various forms.

Lumbar spondylolisthesis with isthmic defects

The importance of spondylolisthesis, aside from the obvious malalignment and malformation of the affected vertebrae, rests mainly on the possibility and the extent of impairment of activity. In this discussion the authors are concerned mainly with the myelographic signs associated with spondylolisthesis in patients with isthmic changes.

Cervical spinal stenosis

Cervical spinal stenosis occurs at the craniovertebral junction, usually incident to a congenital malformation, or it appears as a developmental defect with diffuse narrowing of the cervical canal. In its acquired form the lesion may be limited to one or two levels, or it may be more extensive and affect three or more segments.

Degenerative spondylolisthesis with an intact neural arch

Whereas the skeletal, anatomic, and clinical aspects of this condition have been scrutinized in detail, the radiologic changes have received less attention. In this discussion the plain film changes are briefly reviewed, and emphasis is directed toward the myelographic manifestations that reflect intraspinal and intraforaminal instrusions and their clinical sequelae.

Umbilical uptake of amino acids in the unstressed fetal lamb

The whole blood concentrations of 22 amino acids were measured in a chronic, unstressed fetal lamb preparations. Samples were taken daily from the umbilical artery, umbilical vein, and maternal artery over the latter quarter of gestation. 73 sets of samples (from the umbilical artery and vein and the maternal artery) from 13 animals were analyzed for amino acid levels. Oxygen contents were determined simultaneously in 48 sets (umbilical artery and vein) to relate fetal oxygen consumption to amino acid uptake via the umbilical circulation. The results indicate that there is no umbilical uptake of the acidic amino acids, glutamate and aspartate; there is, in fact, a net flux of glutamate out of the fetus into the placenta. As both of these amino acids are major constituents of body proteins, the data indicate that they are formed within the fetus. The umbilical uptake of some neutral and basic amino acids (e.g., valine, leucine, isoleucine, arginine, phenylalanine, and tyrosine) is in considerable excess of estimated growth requirements, suggesting that some amino acids undergo extensive transamination and oxidative degradation in the fetus. Finally, the net uptake of nitrogen, carbon, and calories by the growing ovine fetus in the form of amino acids, glucose, and lactate is compared to estimated requirements as determined in previous studies.

Cerebral metabolism in sheep: a comparative study of the adult, the lamb, and the fetus

The cerebral uptakes of glucose, oxygen, lactate, pyruvate, acetoacetate and beta-hydroxybutyrate were compared in the adult, the fetal, and the newborn sheep. Beginning 1-2 days after surgery, we withdrew samples simultaneously from an artery and from the sagittal sinus for up to 2 wk. At all ages glucose was the only substrate taken up in significant quantity relative to oxygen. The glucose-oxygen quotients were 0.98 less than 1.03 less than 1.08 in adults; 0.92 less than 0.99 less than 1.06 in lambs; 0.92 less than 0.98 less than 1.03 in fetuses. These quotients were not significantly different. There was a significant (P less than .05) arteriovenous difference for lactate in the adult (-0.031 mM), but not in the lamb or fetus. A significant (P less than .05) arteriovenous difference pyruvate was found in the adult (-0.013 mM) and in the fetus (-0.020 mM). The findings of a glucose-oxygen quotient of approximately 1 and the lack of significant lactate production in fetal sheep brain are consistent with the hypothesis that anerobic glycolysis is unimportant to the steady-state cerebral metabolism of the fetal sheep.

Failure of association of premature rupture of membranes with respiratory-distress syndrome

Records on 16,458 consecutive births were examined to determine associations between the respiratory-distress syndrome of the newborn and cesarean section, maternal diabetes, ante-partum hemorrhage, toxemia of pregnancy, low one-minute Apgar scores and prolonged rupture of fetal membranes. Groups of infants were compared by four-week gestational age blocks. One-minute Apgar scores of less than 5 and of less than 8 were associated with a significant ( less than 0.05) increase in the incidence of respiratory-distress syndrome at gestational ages beyond 30 weeks. Cesarean section was associated with a significant increase after 34 weeks of gestation. There was no association between the syndrome and toxemia of pregnancy, ante-partum hemorrhage or prolonged rupture of fetal membranes. These data do not support the hypothesis that there is a lower incidence of the respiratory-distress syndrome in infants born after prolonged rupture of fetal membranes.

The Circadian Rhythm of Flight Activity in the Mosquito Aedes Aegypti (L.): The Phase-Setting Effects of Light-On and Light-Off

1. The circadian flight-activity of individual, sugar-fed Aedes aegypti females has been studied, using the flight-sound as an indicator of activity.

2. The activity appears to be controlled by an endogenous rhythm with a period of 22-24 hr. in constant dark and about 26 hr. in constant light.

3. Both light-on and light-off have phase-setting effects. Under favourable conditions, peaks of activity occur 13-14 hr. after light-on and 22-23 hr. after light-off. Both these peaks persist in constant dark following an LD 4:20 regime.

4. The total amount of flight-activity is correlated with the duration of light (70 lux) in the 24 hr. period.

The Circadian Flight Activity of the Mosquito, Anopheles Gambiae: Phase Setting by the Light Regime

1. The circadian cycle of flight activity of individual, sugar-fed, Anopheles gambiae females has been studied, using the flight-sound as an indicator of activity.

2. In an LD 12:12 régime (alternating 12 hr. light: 12 hr. dark), activity peaks follow both light-off and light-on. The mosquitoes are moderately active in the dark, but are inactive in the light after the first half-hour.

3. If the light period is extended, the activity is delayed until light-off. Light appears to have an inhibitory effect, but the insects may show some activity towards the end of a 48 hr. light period.

4. Cyclical activity continues in constant dark with a period of approximately 23 hr. A late light-off resets the cycle; an early light-off does not.

5. When the LD 12:12 régime is advanced by 6 hr. the cycle is re-entrained within 2-3 days. Light in the second half of the subjective night appears to advance the cycle.

6. It is suggested that the activity is controlled by an endogenous rhythm which possibly controls the release of an excitatory hormone. The effect of light may be mediated through an inhibitory hormone.