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The dopamine D4 receptor structurally and pharmacologically resembles the dopamine D2 and D3 receptors. Clozapine, an atypical antipsychotic that is relatively free of the adverse effects of drug-induced parkinsonism and tardive dyskinesia, binds to the D4 receptor with an affinity 10 times higher than to the D2 and D3 receptors. This may explain clozapine's atypical properties. Here we report the existence of at least three polymorphic variations in the coding sequence of the human D4 receptor. A 48-base-pair sequence in the putative third cytoplasmic loop of this receptor exists either as a direct-repeat sequence (D4.2), as a fourfold repeat (D4.4) or as a sevenfold repeat (D4.7). Two more variant alleles were detected in humans. Expression of the complementary DNA for the three cloned receptor variants showed different properties for the long form (D4.7) and the shorter forms (D4.2, D4.4) with respect to clozapine and spiperone binding. To our knowledge, this is the first report of a receptor in the catecholamine receptor family that displays polymorphic variation in the human population. Such variation among humans may underlie individual differences in susceptibility to neuropsychiatric disease and in responsiveness to antipsychotic medication.

The classification of ultrasonic liver images is studied, making use of the spatial gray-level dependence matrices, the Fourier power spectrum, the gray-level difference statistics, and the Laws texture energy measures. Features of these types are used to classify three sets of ultrasonic liver images-normal liver, hepatoma, and cirrhosis (30 samples each). The Bayes classifier and the Hotelling trace criterion are employed to evaluate the performance of these features. From the viewpoint of speed and accuracy of classification, it is found that these features do not perform well enough. Hence, a new texture feature set (multiresolution fractal features) based on multiple resolution imagery and the fractional Brownian motion model is proposed to detect diffuse liver diseases quickly and accurately. Fractal dimensions estimated at various resolutions of the image are gathered to form the feature vector. Texture information contained in the proposed feature vector is discussed. A real-time implementation of the algorithm produces about 90% correct classification for the three sets of ultrasonic liver images.

An unstable corpectomy porcine spinal model was created for the testing of anterior spinal fixators including: Kaneda device (KD), combination of Polster-Brinckmann prosthesis and Zielke implant (PBZ), and a new prototype device (CH). These spinal implants were examined in a one above/one below corpectomy model to determine the relative stiffness of each construct and the deformation of the adjacent discs under loading. The results indicated that the relative torsion and flexion stiffness were higher for the tested spines fixed with KD and CH. However, the relative compression stiffness of the tested spines was the same for all devices. The rigidity of the spinal constructs, which were measured around the corpectomy region showed the same tendency as above. However, the stiffness of CH and KD constructs were significantly higher than that of the PBZ construct under flexion and torsion. The difference in deformation of the upper and lower adjacent discs was not obvious among the intact spine and the spinal constructs with different devices. Clinical relevances: The corpectomy model represents a "worst case" scenario of spinal instability. In many conditions, spinal reconstructive surgery can restore axial compressive, torsional, and flexural rigidity to normal levels. These experimental conclusions apply to acute restoration of stability, rather than to rigidity after long-term cyclical loading. These three anterior fixators extended to only one cephalad level and one caudal level beyond the corpectomy defect. The new prototype device (CH) has a stability to the Kaneda device. The superior mechanical strength and simpler operative procedure of the new device provide for a potential clinical advantage in restoration of unstable spinal conditions.

Two siblings in a family--a 5-year-old boy and an 8-year-old girl--suffered from progressive headache and gait disturbance in an interval of 1 year, consecutively. Neurologic manifestations were papilledema and truncal ataxia. Both of their computed tomography scans showed a large, well-enhanced tumor located in the cerebellar vermis with secondary hydrocephalus. Both had surgical resection followed by craniospinal irradiation and then chemotherapy. The pathologic findings confirmed the diagnosis of medulloblastomas. The family pedigree disclosed some other cancer in close relatives. These findings suggested a possible role of heredity in the oncogenesis of this tumor. To our knowledge, our cases are the seventh report of familial medulloblastoma occurring in nontwin siblings in the world.

Cerebral hemodynamics were measured, using the Doppler ultrasound technique (directed toward anterior cerebral artery through the anterior fontanel), in 6 patent ductus arteriosus (PDA) patients with large left to right shunt and in 32 neonates before and just following functional closure of ductus arteriosus. PDA was confirmed by color echocardiogram and Doppler flow study. All 6 sick babies had prominent retrograde flow in the descending aorta during diastole. The value of pulsatility index (PI) derived from the components of peak systolic and end--diastolic frequency, was calculated. An obvious higher PI with simultaneous decrease in diastolic Doppler frequency in sick babies (PI = 0.89 +/- 0.05) were detected. On the contrary, the PI valves in the presence of opening of the ductus (PI = 0.65 +/- 0.07) in normal newborn infants didn't differ significantly with those just following functional closure (PI = 0.63 +/- 0.05). These data suggested that PDA might result in the physiologic consequence of ischemic cerebral injury if large left to right shunt occurred.

Immunohistochemical techniques were employed to study the distribution of serotonin (5-HT) immunoreactive neurons in the brainstem of the hamster, guinea pig, rabbit and rat. 5-HT neurons were principally found to be concentrated in the midline raphe nuclei, particularly, the raphe pallidus, raphe obscurus, raphe magnus, raphe median, raphe pontis and raphe dorsalis nuclei. Characteristically, these cell bodies are displayed in bands or wing-like patterns which extend laterally from the raphe into reticular formations. The formations often appear to blend with the catecholamine system. They are particularly evident in the brainstems of the rabbit and hamster which contain wider and more lateral extensions of the serotonergic (5-HT) neurons than those observed in the brainstems of the rat and guinea pig. The widespread distribution of 5-HT immunoreacted cell bodies in the brainstem shows that there are significant prospects of 5-HT in neuronal activities.

Tritiated labeled materials, [3H]proline and [3H]fucose, were used as tracers of the visual pathway by injection into the right eve of the red belly squirrel, After a designated survival period, the animals were sacrificed, and the brains were removed and processed using standard autoradiographic procedures. Sections were then examined under a microscope and some subcortical nuclei including the suprachiasmatic nucleus (SCN), dorsal and ventral lateral geniculate nuclei(dLGN and vLGN), three optic accessory nuclei (i.e., the medial, lateral and dorsal terminal nuclei - MTN, LTN and DTN), the nuclei of the pretectal area(PTN) and the superior colliculus(SC) in the subcortical regions were marked by labeled isotopes. Radioactive materials were found in the pulvinar nucleus(Pul), parabigeminal nucleus(PB) and dorsal lateral pontine gray(DLP). Some nuclei among the targets of retinal projection in the red belly squirrel received their projection bilaterally while others only did contralaterally. In addition, layered structures of the SC and LGN were clearly demonstrated in the brain of the red belly squirrel. Some differences in the optic system between the red belly squirrel and its near relative, the grey squirrel of North American, and other mammals are discussed.

Methods for the production, isolation, and identification of xanthotoxin and bergapten from celery diseased by Sclerotinia sclerotiorum (Libert) de Bary were investigated. The only conditions under which this mold was capable of producing xanthotoxin and bergapten occurred when the mold was actively growing on fresh (metabolizing) celery. Neither compound was found in uninfected celery, in the mold growing on nutrient media, on nutrient media fortified with 30% filter-sterilized celery juice, or on nonmetabolizing celery. Maximal xanthotoxin production of 320 mug per g of dry rotted celery occurred at 20 C, although mycelial growth increased until 30 C. Neither xanthotoxin nor bergapten was found when the mold grew on 11 agricultural commodities other than celery.