DSP-4 has been used as selective toxin for central norepinephrine (NE) systems. The depletion of NE by DSP-4 is thought to result from neurotoxic destruction of locus coeruleus terminals and axons. We have used tyrosine hydroxylase immunocytochemistry (TH-IR), silver stains for neural degeneration, and electron microscopy to examine the morphological effects of DSP-4 treatment on the rat hippocampus. Animal survived for either 2 or 5 weeks after DSP-4 treatment. DSP-4 depleted hippocampal norepinephrine levels to 15% of control values. Abnormally enlarged TH-IR fibers were found in the hippocampus of DSP-4-treated animals. No evidence of fiber degeneration was found following light or electron microscopic examination of the dentate hilus in DSP-4-treated animals. These data suggest that DSP-4 treatment does not destroy NE terminals, but may produce an intraneuronal lesion leading to an accumulation of TH and a depletion of norepinephrine within the terminal fields.

Changes in contractile protein expression during myogenesis are usually categorized as developmentally programmed or neuronally dependent. Studies on aneurogenic chick embryos indicated that the neuronally dependent phase begins at about Embryonic Day 15, immediately prior to the fetal transition in myosin and C-protein expression. The prime candidate for the neuronal event that induces the fetal transition is the conversion to the adult form of singly innervated neuromuscular junctions (NMJs), which occurs contemporaneously with the fetal transition. Using curare to inhibit the conversion to focal innervation, we find that the fetal transition proceeds unimpaired, demonstrating that there is no causal link between the fetal transition and the conversion to focal innervation. Furthermore, because the doses of curare used inhibit motor activity by more than 80%, the fetal transition can occur in the absence of normal levels of motor activity. These observations show that the fetal transition in ovo is not induced by either a specific change in innervation or use. Rather, the dependence on innervation seems to be a consequence of the need for muscle activity to prevent atrophy, and the fetal transition appears to have characteristics more like the preprogrammed contractile protein transitions that precede it.

O4-MedTMP and O6-MedGMP may be incorporated from their 5'-triphosphates into polynucleotides by DNA polymerases. Once incorporated O6-MedGMP leads to errors during further cycles of DNA synthesis with a mutagenic efficiency of 0.3-0.7, the value depending upon the relative dNTP concentrations in the assay. In contrast O4-MedTMP leads to very few errors following its incorporation into DNA. The results demonstrate that O6-MedGMP, once incorporated into DNA, should be destined to give rise to DNA base changes during the second round of DNA synthesis.

Chloroacetaldehyde, a rearranged metabolic product of the human carcinogen vinyl chloride, reacts with the DNA-like polymers poly(dA-dT) and poly(dC-dG) to form etheno-adducts of the adenine and cytosine bases. These treated polymers, when used as templates for E. coli DNA polymerase I in an in vitro assay, show a decreased ability to direct DNA synthesis. At the same time, increased relative levels of non-complementary nucleotides are incorporated. With the poly(dA-dT) templates 1 dGMP residue is incorporated for every approx 60 ethenoadenine residues present whilst no increased misincorporation of dCMP was detected. With the poly(dC-dG) templates 1 misincorporation of dAMP or dTMP occurred in the presence of approx 30 and 80 ethenocytosine residues respectively. A nearest neighbour analysis shows that with the modified poly(dC-dG) templates the majority of the errors were incorporated opposite cytosine (or modified cytosine) bases.

Chemischer InformationsdienstVolume 8, Issue 15 Physical Organic Chemistry ChemInform Abstract: A DERIVATION OF THE SHAPES AND ENERGIES OF THE MOLECULAR ORBITALS OF 1,3-DIPOLES. GEOMETRY OPTIMIZATIONS OF THESE SPECIES BY MINDO 2 AND MINDO 3 P. CARAMELLA, P. CARAMELLASearch for more papers by this authorR. W. GANDOUR, R. W. GANDOURSearch for more papers by this authorJ. A. HALL, J. A. HALLSearch for more papers by this authorC. G. DEVILLE, C. G. DEVILLESearch for more papers by this authorK. N. HOUK, K. N. HOUKSearch for more papers by this author P. CARAMELLA, P. CARAMELLASearch for more papers by this authorR. W. GANDOUR, R. W. GANDOURSearch for more papers by this authorJ. A. HALL, J. A. HALLSearch for more papers by this authorC. G. DEVILLE, C. G. DEVILLESearch for more papers by this authorK. N. HOUK, K. N. HOUKSearch for more papers by this author First published: April 12, 1977 https://doi.org/10.1002/chin.197715048AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume8, Issue15April 12, 1977 RelatedInformation

The afferent and efferent connections of general cortex were studied in two species of turtle,Pseudemys scripta and Chrysemys picta. The thalamic distribution of labeled cells following cortical applications of horseradish peroxidase (HRP) indicated that at least 3 dorsal thalamic nuclei, the dorsal lateral geniculate nucleus, nucleus ventralis and the nucleus dorsolateralis anterior, project to general cortex. When cortical applications of HRP were combined with intraocular injections of tritiated proline in the same animal, autoradiographically labeled retinal terminations were found among the dendrites of lateral geniculate neurons containing the HRP reaction product. These experiments demonstrated that the dorsal lateral geniculate nucleus not only projects to general cortex, but also receives retinal input. Thus, gereral cortex in the turtle is a target of a visual pathway which relays in the dorsal thalamus. Cortical lesions produced anterograde degeneration in the same thalamic nuclei which the HRP experiments demonstrated project to cortex, thereby indicating that the dorsal thalamus and general cortex have reciprocal connections in the turtle. These same experiments with cortical lesions demonstrated that general cortex also sends projections to the optic tectum and tegmentum of the midbrain. These afferent and efferent connections of general cortex in the turtle are compared with the connections of general cortex in other reptilian groups and with those of neocortex in mammals.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA derivation of the shapes and energies of the molecular orbitals of 1,3-dipoles. Geometry optimizations of these species by MINDO/2 and MINDO/3Pierluigi Caramella, Ruth W. Gandour, Janet A. Hall, Cynthia G. Deville, and K. N. HoukCite this: J. Am. Chem. Soc. 1977, 99, 2, 385–392Publication Date (Print):January 1, 1977Publication History Published online1 May 2002Published inissue 1 January 1977https://pubs.acs.org/doi/10.1021/ja00444a013https://doi.org/10.1021/ja00444a013research-articleACS PublicationsRequest reuse permissionsArticle Views275Altmetric-Citations60LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts