Biomedical subjects

B S Brann

Publications and source records attributed to B S Brann.

6 recordsLinked to original sources

PubMed1991

Asymmetric growth of the lateral cerebral ventricle in infants with posthemorrhagic ventricular dilation.

Lateral cerebral ventricular volume in 36 preterm infants with or without an intraventricular hemorrhage, and with or without posthemorrhagic hydrocephalus, was measured longitudinally and compared with the ventricular index measurements of the same ventricles. A poor correlation was found (r2 = 0.67). To determine a reason for this poor relationship, we analyzed the volumes of the regions of the ventricles by a segmental volume analysis. The occipital region of the lateral cerebral ventricle enlarged at a much faster rate (1.904 +/- 0.477 ml/day) than either the anterior region (0.546 +/- 0.253 ml/day; p less than 0.01) or the middle region (-0.209 +/- 0.334 ml/day; p less than 0.01) in infants with posthemorrhagic hydrocephalus. The rate of growth of the middle region of the lateral cerebral ventricles was the same for all infants. Linear indexes, such as the ventricular index and the lateral ventricular ratio, do not allow for accurate serial estimates of ventricular size in posthemorrhagic hydrocephalus because of asymmetric growth of the lateral cerebral ventricle. We conclude that sequential volume measurements are more useful than ventricular index measurements to follow ventricular size sequentially in infants with posthemorrhagic hydrocephalus.

Cerebral Hemorrhage↗

PubMed1990

Measurement of progressive cerebral ventriculomegaly in infants after grades III and IV intraventricular hemorrhages.

To develop guidelines that might help predict prospectively which infants with severe intraventricular hemorrhage (IVH) would require intervention, we obtained serial cranial sonograms to measure the rate of growth of cerebral ventricular volumes in 48 preterm infants with and without IVH. The infants were divided into three groups: (1) those with no IVH (22 infants), (2) those with IVH with acute ventricular dilation (13 infants), and (3) those with IVH with progressive ventricular dilation requiring intervention (13 infants). The decision to intervene because of progressive ventricular dilation was based on clinical criteria and the subjective assessment of increasing ventricular size on weekly cranial sonograms. The rate of cerebral ventricular volume growth in infants with IVH who needed intervention was greater (4.2 +/- 3.3 ml/day) than that in infants without IVH (0.0 +/- 0.1 ml/day; p less than 0.001) and in infants with IVH and acute ventricular dilation (0.0 +/- 0.2 ml/day; p less than 0.001). Using these data, we generated guidelines for predicting prospectively which infants with IVH and ventricular dilation will need intervention for posthemorrhagic hydrocephalus. The guidelines were then confirmed prospectively in 10 infants.

Cerebral Hemorrhage↗

PubMed1990

Quantification of neonatal cerebral ventricular volume by real-time ultrasonography. Derivation and in vitro confirmation of a mathematical model.

The derivation and in vitro confirmation of a method for the calculation of cerebral ventricular volume determined by cranial ultrasonography is described. The derivation depends on use of the cylindrical coordinate method. Confirmation was performed by construction of ultrasound phantoms from latex balloons embedded in a talc/gelatin matrix. Seventeen phantoms of volumes ranging from 10 to 60 mL were measured. The known volume was then compared to the calculated volume by linear regression analysis. The regression analysis indicated a close correlation between the actual volume of the phantoms and the calculated volume with r = 0.96. Various sources of error in the method are discussed. Our results indicate that the cylindrical coordinate mathematical model when applied to cranial ultrasonography images accurately measures cerebral ventricular volumes.

Analysis of Variance↗

PubMed1990

Quantification of neonatal cerebral ventricular volume by real-time ultrasonography. In vivo validation of the cylindrical coordinate method.

Posthemorrhagic ventricular dilation is a common clinical problem in preterm infants who have incurred an intraventricular hemorrhage. Presently there are no clinically applicable methods to follow quantitatively the progression of ventricular dilation at bedside. We describe the in vivo validation of a method to measure ventricular volume using bedside real-time cranial ultrasonography. Six infants undergoing either serial lumbar punctures or cerebral ventricular reservoir taps for posthemorrhagic hydrocephalus were studied. The cerebrospinal fluid (CSF) volume removed ranged from 5.5 mL to 30 mL. A strong correlation was found (r2 = 0.84) between the volume of CSF removed by reservoir tap and the change in ventricular volume calculated by the ultrasound method, whereas the correlation between the volume of CSF removed at lumbar puncture and the change in ventricular volume calculated by the ultrasound method was not as strong (r2 = 0.70). Limitations and sources of error in the method are discussed. We conclude that this procedure is accurate and offers a quantitative method to follow longitudinally posthemorrhagic progressive ventricular dilation.

Cerebral Hemorrhage↗

PubMed1988

Cerebral cortical blood flow and oxygen metabolism in normocythemic hyperviscous newborn piglets.

Our study tests the hypothesis that hyperviscosity independent of arterial O2 content reduces cerebral cortical blood flow, O2 delivery, and O2 uptake. After baseline determinations, ten 2- to 4-day-old awake spontaneously breathing piglets were given an intravenous infusion (5 ml.kg-1, body weight) of concentrated cryoprecipitate, whereas eight controls received normal saline. Cerebral cortical blood flow, arterial and superior sagittal sinus O2 content, whole blood viscosity, hematocrit, blood gases, and plasma fibrinogen concentrations were measured at baseline and 3 h after infusion. No significant changes were observed in the control group. Three hours after the infusion of concentrated cryoprecipitate the experimental group showed an increase in whole blood viscosity, whereas hematocrit and arterial O2 content were unchanged. There was a decrease in cerebral cortical blood flow and cerebral cortical O2 delivery, whereas cerebral cortical O2 uptake was unchanged. We conclude that hyperviscosity independent of arterial O2 content reduces cerebral cortical blood flow and that although O2 delivery was reduced in the newborn piglet cerebral cortical O2 uptake was maintained.

Animals↗

PubMedDate not supplied

Subcortical visual function in the newborn.

Early behavioral visual function in infants may not depend upon the geniculocalcarine pathway but may be mediated through more primitive subcortical pathways. This subcortical visual system may exist in early life and be responsible for visual pursuit and perhaps fixation. In some infants with damage to the visual cortex, the subcortical pathway may persist beyond the neonatal period. Three infants with major defects in the visual cortex are reported. These infants displayed persistent preservation of visual pursuit movements without evidence of visual recognition. Limited behavioral expressions of vision in the infant with damage to the visual cortex may not always be an indicator of preserved function of the visual cortex.

Brain↗