Dopamine receptor plasticity following MPTP-induced nigrostriatal lesions in the mouse

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) destroys dopamine-containing nigrostriatal neurons and increases the apparent B_max of both D₁ and D₂ binding sites in the striatum. However, the changes of B_max occur at different intervals after the lesion. Up-regulation of D₂ sites becomes evident about 3 weeks after the lesion and lasts for about 3 months. In contrast, about 3 months are required for the up-regulation of D₁ sites and increased binding is still evident after 5 months.     

New agents for cutaneous photoprotection: derivatives of α-amino acids, 4-aminobenzoic and 4-methoxycinnamic acids

Derivatives of sulfur-containing or sulfur-free α-amino acids, 4-aminobenzoic and 4-methoxycinnamic acids, which are potential sun screens, have been synthesized. The effects on melanin formation of 2 compounds (2 and 12) were studied via enzymatic reactions and cell culture. It was shown that these 2 compounds can enhance pigmentation.     

Synthesis of 3-acetoxyazetidin-2-ones and 3-hydroxyazetidin-2-ones with antifungal and antibacterial activity

The synthesis of a series of 3-acetoxyazetidin-2-ones 3a–n and 3-hydroxyazetidin-2-ones 6a–j is reported together with the antibacterial and antifungal evaluation of these compounds. An additional series of 3-acetoxyazetidin-2-ones 11a–h which possess a free carboxylic acid group on the N-1 aryl ring were obtained by treatment of suitably substituted Schiff bases 10a–h with acetoxyacetyl chloride. The novel bicyclic structures 7-acetoxy-6-phenyl-5-thia-1-azabicyclo[4.2.0]octan-8-one 13 and 7-hydroxy-6-phenyl-5-thia-1-azabicyclo[4.2.0]octan-8-one 14 were also obtained. Many of the compounds displayed antifungal activity in vitro when evaluated against the pathogenic fungi Cryptococcus neoformans, Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, and Trichosporon cutaneum, while 3-acetoxyazetidin-2-ones 11a–h containing a free carboxylic acid group on the N-1 aryl ring displayed antibacterial activity against Staphylococcus aureus, Proteus vulgaris, Pseudomonas aeruginosa, Bacillus subtilis, Klebsiella aerogenes and Escherischia coli.     

New and future developments in cerebrovascular ultrasound,magnetic resonance angiography,and related techniques

Four-dimensional (4D) analysis of atherosclerotic plaque and wall motion, the application of 4D ultrasound to the study of atherogenesis, and the incorporation of ultrasound data into flow models for simulation of cerebrovascular hemodynamics are new frontiers in diagnostic ultrasound that use computer vision and optical flow techniques to exploit the full potential of real-time imaging and Doppler studies. New approaches to improve blood vessel delineation with ultrasound include application of contrast agents, harmonic imaging, and red blood cell density imaging. An assessment of the potential clinical utility of these new developments in cerebrovascular ultrasound requires an analysis of comparable trends in magnetic resonance (MR) technology, eg, rapid advances in the fields of MR angiography, dynamic contrast-enhanced MR, and MR diffusion imaging. Likewise, the value of ultrasound techniques for the measurement of blood flow to evaluate cerebrovascular hemodynamics must be compared to related methods in magnetic resonance, such as dynamic MR inflow tracking. This article addresses several new and future developments in cerebrovascular ultrasound and discusses their relative merits in terms of ongoing research in the field of magnetic resonance angiography, imaging, and related techniques. © 1995 John Wiley & Sons, Inc.     

Temporomandibular joint: computed tomographic three-dimensional reconstruction

Computed tomography represents an effective and highly automated method to display biomedical data from many sources. It has a number of advantages over previous reconstruction methods, particularly the ability to automatically locate object-boundary outlines and produce shaded three-dimensional images of reconstructed data. A three-dimensional reconstruction of the temporomandibular joint was performed successfully on five cadaver heads using the Phillips Tomoscan and IP5000 image processor. The program used in this study of the temporomandibular joint is divided into five distinct steps: data gathering, rotation and projection, filtering, smoothing, and shading. Comparison of this type of data is important in the study of the normal and abnormal anatomy of the temporomandibular joint. Similarly, quantitative data obtained from reconstructed computed tomograms can be used to study normal anatomy in vivo and to examine the effects of various treatment modalities on the size and morphologic characteristics of tumors and other pathologic entities.