Einflüsse des Schlafes auf die GnRH-Ansprechbarkeit der laktotrophen Zellen der Hypophyse

Schlu?folgerung ?nderungen der Ansprechbarkeit der laktotrophen Zellen auf GnRH w?hrend des Tag-Nacht-Schlaf-Zyklus k?nnen zumindest teilweise die zirkadianen Variationen der Prolaktin-Sekretion erkl?ren.     

Facial morphology and occlusion at the stage of early mixed dentition in cleft lip and palate patients treated with delayed closure of the hard palate

Cephalometric radiographs and dental study casts were analyzed in a group of 23 seven-year-old cleft lip and palate patients, 16 with unilateral and 7 with bilateral cleft. The patients' primary surgical procedures had been completed except for closure of the cleft in the hard palate. For comparison, similar records from another group of patients, 18 with unilateral and 8 with bilateral cleft lip and palate, were studied. In these cases the cleft of the hard palate had been repaired in infancy, using a vomer flap procedure. The results indicated that midfacial growth and dental occlusion of the unilateral cleft sample was significantly better in patients whose closure of the hard palatal cleft had been delayed to the stage of mixed dentition than where repair had been performed with a vomer flap in infancy. No differences were found, however, between similar subgroups with bilateral cleft lip and palate.     

Regional cerebral blood flow assessed by 133Xe inhalation and emission tomography: normal values

Regional cerebral blood flow (rCBF) in the cerebral hemispheres and the cerebellum was measured by single photon emission computed tomography with inhalation of 133Xe in 39 normal volunteers at test. The goal of this study was to assess the normal flow pattern and its variations. Five parallel tomographic slices through the brain were recorded with a resolution element of 1.7 X 1.7 X 2.0 cm (full width at half maximum). The blood flow distribution showed that the predominantly gray matter areas displayed flow approximately double that of the predominantly white matter regions. The CBF distribution was practically symmetrical with a side-to-side difference averaging 1.4 +/- 1.4 ml/100 g/min. This means that a difference exceeding 4.2 ml/100 g/min (approximately 9% of mean CBF) is abnormal with a confidence level of below 5%. The measured average CBF and cerebellar blood flow were 56 +/- 7 and 54 +/- 6 ml/100 g/min (mean +/- 1 SD), respectively. A significant correlation was found between CBF and PCO2, and between CBF and age. Repeat measurements in an additional 30 subjects showed a day-to-day variability of -0.2 +/- 6.4 ml/100 g/min of the difference between the first and the second measurement. This corresponds to random methodological and biological errors of 6.4/square root 2 = 4.6 ml/100 g/min and is a measure of the overall intraindividual variability. Xenon-133 tomography is atraumatic and affords rCBF images free of the superposition artifacts that practically invalidate the nontomographic approaches in the studies of cerebrovascular disease. The rCBF tomograms are blurred, particularly due to Compton scatter. Relative to this factor, the errors caused by local variations in the tissue:blood partition coefficient are less important.     

Sonography of the internal capsule and basal ganglia in infants. Part II. Localization of pathologic processes in the sagittal section through the caudothalamic groove

Sagittal sonograms through the caudothalamic groove routinely display a gangliothalamic ovoid delimited by the lateral ventricle, the perimesencephalic cistern, and the radiations of the corpus callosum. The caudothalamic groove divides the superior surface of the ovoid into an anterior caudate arc and a posterior thalamic arc. The cerebral peduncle divides the inferior surface of the ovoid into an anterior ganglial arc, a middle peduncular arc, and a posterior thalamic arc. The genu of internal capsule constantly courses from the anterior end of the caudothalamic groove down to the peduncular arc and is easily identified. The gangliothalamic ovoid exhibits four obliquely oriented bands of increased and decreased echogenicity. The anteriormost hyperechoic band 1 corresponds to the head of the caudate nucleus. Hypoechoic band 2 corresponds to the globus pallidus, genu of the internal capsule, and cerebral peduncle. Hyperechoic band 3 corresponds to the ventral and lateral thalamic nuclei (exclusive of the pulvinar). Hypoechoic band 4 corresponds to the pulvinar. Lesions of the medial nucleus of the globus pallidus appear as hyperechoic foci that abut on the anterior surface of genu just above the peduncle and that have a narrow convex caudal margin. Lesions of the lateral nucleus of globus pallidus abut on the genu distant from the peduncle, spare the medial nucleus adjacent to the peduncle, and have a broad caudal border. Lesions of the head of caudate nucleus affect the anterior pole of the ovoid; those of the body affect the caudate arc superior to the caudothalamic groove. Thalamic lesions increase the echogenicity of bands 3 and 4.