Responding for rewarding brain stimulation: cocaine and isradipine plus naltrexone

We recently identified a gene which shows high similarity to the beta-spectrin gene but with a different chromosomal location from either of the two known beta-spectrin genes [T. Nagase, K.-I. Ishikawa, D. Nakajima, M. Ohira, N. Seki, N. Miyajima, A. Tanaka, H. Kotani, N. Nomura, O. Ohara, Prediction of the coding sequences of unidentified human genes: VII. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro, DNA Res. 4 (1997) 141-150]. In order to further characterize this new spectrin gene and its product, we isolated the rat counterpart of this gene and analyzed it in terms of its protein coding sequence, the tissue distribution of its mRNA and the product, and the regional distribution of the mRNA and the product in the brain. The results indicated that this gene was most abundantly transcribed in the brain and neurons were the predominant cell-type to express this gene. In particular, Purkinje cells were the richest in this gene product, and this new form of beta-spectrin was found more prominently in the dendrites than in the cell bodies. Since the expression pattern and the subcellular localization of this gene product were quiet distinct from those of the two beta-spectrin isoforms already characterized, this beta-spectrin gene would play an important role in neuronal membrane skeleton although it has been overlooked to date.     

Visual half-field Stroop effects with spatial separation of words and color targets

Past inconsistencies in the occurrence of differential visual half-field Stroop effects were addressed in two experiments using a visual half-field presentation technique incorporating brief displays (100 ms) and a fixation task designed to ensure proper eye fixation at display onset. Experiment 1 used displays in which distractor words and color targets were presented in contralateral visual fields. Experiment 2 compared contralateral with ipsilateral displays where words and color targets appeared one above the other in the same visual field. Stroop effects were larger whenever a word occupied the right as opposed to the left visual field, regardless of whether the color target was left or right. Results are consistent with the idea that words are processed more efficiently or automatically in right visual field/left hemisphere presentations.     

Considerations for the orthopedic nurse in diagnosis and treatment of adolescent sports injuries

Injured adolescent athletes are challenging clients for the primary practitioner. Their unique physiological and psychological attributes dictate changes in traditional orthopedic practice and call for a holistic patient focus to address their varied needs. Understanding of common athletic injuries will effectively guide the practitioner's clinical evaluation and assist in recognizing those patients requiring more complex orthopedic diagnosis and care.     

Studies of the electron transport chain of the euryarcheon Halobacterium salinarum: indications for a type II NADH dehydrogenase and a complex III analog

The components involved in the respiratory system of the euryarcheon Halobacterium salinarum were investigated by spectroscopic and polarographic techniques. Previous results about the cytochrome composition could be verified. However, under low oxygen tension, the expression of a d-type cytochrome was detected. Membranes exerted an NADH- and succinatecytochrome-c oxidoreductase as well as an NADH and succinate oxidase activity. These activities could be blocked by the following inhibitors: 7-jodocarboxylic acid, giving evidence for the presence of a type II NADH dehydrogenase, antimycin A, and myxothiazol, indicating the presence of a complex III analog, and the typical succinate dehydrogenase (SDH) and terminal oxidase inhibitors. Complex I inhibitors like rotenone and annonine were inactive, clearly excluding the presence of a coupled NADH dehydrogenase. In addition, no [Fe-S] resonances in the region of the NADH dehydrogenase (NDH) clusters could be observed after NADH addition. One of the terminal oxidases could be shown to act as a cytochrome-c oxidase with a Km value of 37 microM and an activation energy of 23.7 kJ/mol. The relative molecular mass of the endogenous c-type cytochrome could be determined as 14.1 kD. The complex III analog could be enriched after detergent extraction with Triton X-100 and hydroxylapatite (HTP) chromatography. The partially purified complex contained a Rieske iron-sulfur cluster, b- and c-type cytochromes, and was catalytically active in the decylubiquinone-cytochrome-c oxidoreductase assay.     

Localization of Myf-5, MRF4 and alpha cardiac actin mRNAs in regenerating Xenopus skeletal muscle

Dendrotoxin I (DTX-I) is a 60-residue peptide from the venom of the black mamba snake Dendroaspis polylepis, which binds to neuronal K+ channels. The structure reported previously for DTX-I was synthesized for the first time by a solution procedure. The synthetic product was confirmed to have the correct primary and disulfide structure determined by peptide mapping, sequence analysis and mass measurements. Comparison of synthetic DTX-I with the natural one by high-performance liquid chromatography and capillary zone electrophoresis, as well as by sequence analysis, revealed that the Asn residue at position 12 in the synthetic peptide was Asp in the natural product. Synthesis of DTX-I with Asp at position 12 gave a peptide identical with the natural product in all aspects. NMR analysis of synthetic [Asn12]- and [Asp12]-DTX-I also supported our findings that the Asn residue at position 12 in the DTX-I molecule should be revised as Asp. [Asn12]- and [Asp12]-DTX-I had very similar binding affinities when tested against radiolabeled dendrotoxin binding to rat brain synaptosomal membranes.