Failure of acetylmethadol in treatment of narcotic addicts due to nonpharmacologic factors.

Acetylmethadol, a new narcotic substitute, has a longer duration of action than methadone. Seventeen subjects, former heroin users currently under methadone treatment, entered a study of the toxicity and efficacy of this drug. Only nine subjects completed the assessment phase of the study and began the acetylmethadol phase, and only one completed the 8-week study phase. Hence, no conclusions can be drawn about acetylmethadol''s efficacy. The high attrition rate was unrelated to pharmacologic factors; the subjects were concerned that if this drug was effective there would be no methadone to take home and hence no opportunity to trade, sell or "play with" (that is, combine with other drugs) the latter. This study emphasizes the difficulty in determining the efficacy of specific drug treatments for opiate-dependent patients.     

Citrate Mannitol Agar Medium for Separating Escherichia coli Paracolons from Shigella

A culture medium is described which not only differentiates Shigella from Escherichia coli but also serves as the basis for an extremely simple test which specifically identifies E. coli. A test that will identify an organism as E. coli is more useful than one that merely groups this species with other non-Shigella organisms. The theoretical basis for specificity of the test for E. coli and other uses for the medium are discussed.     

Hexazonium pararosaniline as a fixative for animal tissues

Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution.     

Norms in the politics of housing for minorities: Evidence from a French,a German and a US metropolitan area

Throughout Western societies, policy‐makers who address the problems of disadvantaged ethnic and immigrant minorities confront norms that prescribe equal or preferential treatment for these groups. Variations in these norms make significant differences in policy‐making. Based on evidence from housing and planning policies and a standardized survey of local élites in comparable German, French and US metropolitan areas, this article analyses how these norms altered logics of policy‐making. Normative differences help to explain why policies to house minorities proved more successful in the German setting than in the French. Contrasts in central‐local relations, in local government, in political parties and in the social and economic background of policy‐making fail to account for the difference that these norms make. In the American setting normative ambiguities combined with institutional, social and spatial differences to render parallel norms comparatively ineffective.     

Mammalian Myosin-18A,a Highly Divergent Myosin

The Mus musculus myosin-18A gene is expressed as two alternatively spliced isoforms, α and β, with reported roles in Golgi localization, in maintenance of cytoskeleton, and as receptors for immunological surfactant proteins. Both myosin-18A isoforms feature a myosin motor domain, a single predicted IQ motif, and a long coiled-coil reminiscent of myosin-2. The myosin-18Aα isoform, additionally, has an N-terminal PDZ domain. Recombinant heavy meromyosin- and subfragment-1 (S1)-like constructs for both myosin-18Aα and -18β species were purified from the baculovirus/Sf9 cell expression system. These constructs bound both essential and regulatory light chains, indicating an additional noncanonical light chain binding site in the neck. Myosin-18Aα-S1 and -18Aβ-S1 molecules bound actin weakly with K_d values of 4.9 and 54 μm, respectively. The actin binding data could be modeled by assuming an equilibrium between two myosin conformations, a competent and an incompetent form to bind actin. Actin binding was unchanged by presence of nucleotide. Both myosin-18A isoforms bound N-methylanthraniloyl-nucleotides, but the rate of ATP hydrolysis was very slow (<0.002 s⁻¹) and not significantly enhanced by actin. Phosphorylation of the regulatory light chain had no effect on ATP hydrolysis, and neither did the addition of tropomyosin or of GOLPH3, a myosin-18A binding partner. Electron microscopy of myosin-18A-S1 showed that the lever is strongly angled with respect to the long axis of the motor domain, suggesting a pre-power stroke conformation regardless of the presence of ATP. These data lead us to conclude that myosin-18A does not operate as a traditional molecular motor in cells.