Biomedical subjects

H C Lou

Publications and source records attributed to H C Lou.

94 records · Page 6Linked to original sources

PubMedDate not supplied

Cerebral magnetic resonance spectroscopy in Rett syndrome. Failure to detect mitochondrial disorder.

A total of eight girls with Rett syndrome were examined, by 31phosphorous magnetic resonance spectroscopy (31P MRS) (4 girls), proton MRS (1H MRS) (4 girls), muscle biopsying (2 girls), and determination of pyruvate and lactate in plasma (5 girls), to investigate the hypothesis of a mitochondrial malfunction as the etiology for this neurologic disorder. Almost all examinations, including electron microscopy in search of structural mitochondrial abnormalities, gave normal results, the only exception being the not unexpected finding of slight neurogenic atrophy in the muscle biopsy specimen from a 15-year-old girl.

Adolescent↗

PubMedDate not supplied

Hypoxic-hemodynamic pathogenesis of brain lesions in the newborn.

For more than a century two opposing views on the pathogenetic mechanisms and the timing of the origin of cerebral palsy (CP) have prevailed: the idea first formulated by Little attributing CP to "difficult deliveries" has been opposed by the view by Freud recognizing fetal influences, and the issue seems to be unsettled. The present review seeks to bridge the gap by recognizing that late prenatal or perinatal hypoxic-hemodynamic insult is a dominating final common path in the pathogenesis of static encephalopathies during development, in particular in premature infants. In turn, however, such lesions are determined by early genetic and environmental influences. The pathogenesis of static encephalopathy should therefore be seen as a chain of events, with its origin before gestation.

Animals↗

PubMedDate not supplied

The apparent diffusion coefficient of water in gray and white matter of the infant brain.

PURPOSE: The purpose was to obtain normal values of the apparent diffusion coefficient (ADC) in the infant brain and to compare ADC maps with T1- and T2-weighted images. METHOD: Diffusion was measured in nine infants with an ECG-gated SE sequence compensated for first-order motion. One axial slice at the basal ganglia level was investigated with the diffusion-encoding gradients in the slice-selection direction. RESULTS: On ADC maps, the corpus callosum and the optic radiations appeared dark before the onset of myelination, and the crus posterior of the internal capsule could be visualized before it appeared on T1- or T2-weighted images. In gray and white matter, the mean ADC ranged from 0.95 x 10(-9) to 1.76 x 10(-9) m2/s. In the frontal and occipital white matter, in the genu corporis callosi, and in the lentiform nucleus, the ADC decreased with increasing age. The cortex/white matter ratio of the ADC increased with age and approached 1 at the age of 30 weeks. CONCLUSION: ADC maps add information to the T1 and T2 images about the size and course of unmyelinated as well as myelinated tracts in the immature brain.

Brain↗

PubMedDate not supplied

Influence of serotinin and norepinephrine on flow capacity/pressure characteristics of feline isolated cerebral arteries.

Isolated feline pial vessel segments (250-400 microns in diameter, 4 mm long) were mounted in Krebs solution in organ baths on L-shaped metal holders connected to pressure transducers. From the distance between the outer limits of the wires (f) and the force recorded by the transducers (F), the transmural pressure and the flow capacity were calculated. Changes in these parameters were produced by increasing the distance between the holders. Norepinephrine (10(-5) M) and serotonin (10(-6) M) were added to the tissue bath at different resting wall tensions. Both norepinephrine and serotonin resulted in contractile responses that were maximal at a resting wall tension of 2 nM/mm. Norepinephrine and serotonin displaced the flow capacity/pressure curve to the right up till at least 112 mm Hg, indicating a displacement of the autoregulatory range to the right.

Animals↗