In vivo imaging of brain incorporation of fatty acids and of 2-deoxy-D-glucose demonstrates functional and structural neuroplastic effects of chronic unilateral visual deprivation in rats

Regional cerebral 'incorporation coefficients' k* of each of 3 labeled long-chain fatty acids -[9,10-3H]palmitate ([3H]PA), [1-14C]arachidonate ([14C]AA) and [1-14C]docosahexaenoate ([14C]DHA)-were measured using quantitative autoradiography in 11 bilateral brain visual areas of 3.5-month-old awake, hooded, Long-Evans rats, and were compared with regional cerebral metabolic rates for glucose (rCMRglc). The rats, which had undergone unilateral orbital enucleation at 15 days of age, were studied either in the dark with eyelids of the intact eye sutured, or when stimulated in a light box with the intact eye open. rCMRglc did not differ between homologous contralateral and ipsilateral visual areas in the dark or during stimulation, but was elevated bilaterally by 25% or more in many visual areas during stimulation compared with dark. Contralateral compared with ipsilateral k* was lower for each fatty acid tracer in superficial gray of the superior colliculus (in dark and during stimulation) and dorsal nucleus of lateral geniculate body (during stimulation). In the dark, k* for [3H]PA was correlated significantly with rCMRglc for the 22 visual areas studied, whereas during stimulation k* for [14C]AA was correlated with rCMRglc. These results suggest that central neuroplastic changes following chronic unilateral enucleation are accompanied by reduced incorporation of [3H]PA, [14C]AA and [14C]DHA into contralateral brain ares that normally receive crossed retinofugal fibers, and by symmetry of rCMRglc in the dark but increased bilateral symmetrical responsiveness of rCMRglc to visual stimulation of the intact eye.     

Coupling of store-operated Ca++ entry to contraction in rat aorta

The purpose of this study was to test whether the elevated intracellular Ca++ level ([Ca++]i) resulting from store-operated Ca++ entry was associated with vascular smooth muscle contraction. Cyclopiazonic acid (CPA), a selective inhibitor of sarcoplasmic reticulum Ca(++)-ATPase, concentration-dependently (1-10 microM) elevated [Ca++]i in rat aorta, as indicated by an increase in the fura-2 340/380 ratio. Simultaneous measurement of contraction demonstrated that 1 and 10 microM CPA induced insignificant and variable amounts of contraction, respectively. Verapamil (10 microM) had relatively little effect on the 1 and 10 microM CPA-elevated [Ca++]i. In contrast, Ni++ (0.1 mM), in the presence of verapamil, abolished the 1 microM CPA-elevated [Ca++]i. Ni++ (0.1 mM) also partially decreased the 10 microM CPA-elevated [Ca++]i and, furthermore, abolished the associated contraction. A higher Ni++ concentration (1 mM) abolished the 10 microM CPA-elevated [Ca++]i that remained after verapamil and 0.1 mM Ni++. Phorbol dibutyrate (10 nM), a protein kinase C activator, potentiated contractions to 1 and 10 microM CPA in the presence of verapamil. Ni++ (0.1 mM) abolished the enhanced contractions, and decreased the elevated [Ca++]i. These results suggest that 1) elevated [Ca++]i due to store-operated Ca++ entry is dissociated from contraction; 2) the elevated [Ca++]i is restricted to at least two noncontractile compartments that can be differentiated by their relative sensitivities to blockade by low (0.1 mM) and higher (1 mM) Ni++ concentrations, and 3) [Ca++]i elevation within the compartment sensitive to blockade by 0.1 mM Ni++ can be coupled to contraction via protein kinase C activation.     

Quantitative brain magnetic resonance imaging in attention-deficit hyperactivity disorder

BACKGROUND: Anatomic magnetic resonance imaging (MRI) studies of attention-deficit hyperactivity disorder (ADHD) have been limited by small samples or measurement of single brain regions. Since the neuropsychological deficits in ADHD implicate a network linking basal ganglia and frontal regions, 12 subcortical and cortical regions and their symmetries were measured to determine if these structures best distinguished ADHD. METHODS: Anatomic brain MRIs for 57 boys with ADHD and 55 healthy matched controls, aged 5 to 18 years, were obtained using a 1.5-T scanner with contiguous 2-mm sections. Volumetric measures of the cerebrum, caudate nucleus, putamen, globus pallidus, amygdala, hippocampus, temporal lobe, cerebellum; a measure of prefrontal cortex; and related right-left asymmetries were examined along with midsagittal area measures of the cerebellum and corpus callosum. Interrater reliabilities were .82 or greater for all MRI measures. RESULTS: Subjects with ADHD had a 4.7% smaller total cerebral volume (P = .02). Analysis of covariance for total cerebral volume demonstrated a significant loss of normal right > left asymmetry in the caudate (P = .006), smaller right globus pallidus (P = .005), smaller right anterior frontal region (P = .02), smaller cerebellum (P = .05), and reversal of normal lateral ventricular asymmetry (P = .03) in the ADHD group. The normal age-related decrease in caudate volume was not seen, and increases in lateral ventricular volumes were significantly diminished in ADHD. CONCLUSION: This first comprehensive morphometric analysis is consistent with hypothesized dysfunction of right-sided prefrontal-striatal systems in ADHD.     

A Tracking System for Pulsed Ultrasound Images: Application to Quantification of Fetal Breathing Movements

A tracking system for quantification of moving structures from a real-time B-scan ultrasound image is described. The system provides a hard copy tracing of the movements with a resolution that is uncoupled from the wavelength of the ultrasound frequency employed. In the present instrument, a laboratory resolution of 0.06 mm and a differential target velocity of 961 mm/s has been achieved which has been more than adequate for tracking and recording all observed fetal movements, including the relatively high speed fetal hiccough. Both mechanical target tests and in vivo fetal breathing movements associated with maternal glucose loading are reported herein.     

A Pilot Clinical PEP Monitor

An instrument for the continuous measurement of pre-ejection period (PEP) in the human fetus using Doppler ultrasound is presented. An important feature of the instrument is its ability to track the continuously changing location of the reflections. The design includes a recently developed nonlinear filtering technique that is quite insensitive both to the large amounts of noise of biologic origin and the random dynamic amplitude variations. The efficiency of the scheme is illustrated by simulated and clinical tests.