Structural and mass spectral studies on some multiply bonded diosmium tetracarboxylate compounds

The compounds Os₂(O₂CCH₃)₄Cl₂,1 and Os(O₂CC₂H₅)₄Cl₂, 2, have been structurally characterized. Both compounds crystallize in space group P2₁/n. For 1 the unit cell parameters are a = 6.546(1) Å, b = 8.950(1) Å, c = 12.533(1) Å, β = 90.17(1)° and Z = 2; for 2 they are a = 6.792(2) Å, b = 10.519(3) Å, c = 13.372(4) Å, β = 89.27(3)° and Z = 2. Both molecules have approximate D_4th symmetry with important dimensions as follows: for 1, Os≡Os 2.314(1) Å, OsCl 2.448(2) Å; for 2, Os≡Os 2.316(2) Å, OsCl 2.430(5) Å. The mass spectra of these compounds as well as that of Os₂(O₂CC₃H₇)₄Cl₂,3, are reported and discussed.     

Effect of clenbuterol on sarcoplasmic reticulum function in single skinned mammalian skeletal muscle fibers

We examined the effect of the₂-agonist clenbuterol (50 µM)on depolarization-induced force responses and sarcoplasmic reticulum (SR) function in muscle fibers of the rat (Rattusnorvegicus; killed by halothane overdose) that had beenmechanically skinned, rendering the₂-agonist pathway inoperable.Clenbuterol decreased the peak of depolarization-induced forceresponses in the extensor digitorum longus (EDL) and soleus fibers to77.2 ± 9.0 and 55.6 ± 5.4%, respectively, ofcontrols. The soleus fibers did not recover. Clenbuterol significantlyand reversibly reduced SR Ca²⁺loading in EDL and soleus fibers to 81.5 ± 2.8 and 78.7 ± 4.0%, respectively, of controls. Clenbuterol also producedan ~25% increase in passive leak ofCa²⁺ from the SR of the EDL andsoleus fibers. These results indicate that clenbuterol has directeffects on fast- and slow-twitch skeletal muscle, in the absence of the₂-agonist pathway. Theincreased Ca²⁺ leak in the triadregion may lead to excitation-contraction coupling damage in the soleusfibers and could also contribute to the anabolic effect of clenbuterolin vivo.

     

Treatment of Patients with Systemic Lupus Erythematosus including Nephritis with Chlorambucil

Six female patients with systemic lupus erythematosus (S.L.E.) have been treated with chlorambucil. In five the decision was taken after failure by corticosteroids to control progressive renal disease in the face of unacceptable corticosteroid toxicity. After the introduction of chlorambucil renal function improved and all patients remain well six, six, five, three, and two-and-a-half years later, respectively. On renal biopsy five had focal proliferative glomerulonephritis. Repeat biopsy in two cases showed quantitative improvement. The sixth patient was treated with chlorambucil because of failure by corticosteroids to control peripheral vascular lesions and haemolysis and she remains well four years later. In four patients is it probable that amenorrhoea was related to chlorambucil treatment, but there were no other important side effects although one patient developed a degree of marrow depression during treatment. Chlorambucil may hold advantages over the immunosuppressive drugs normally recommended in this condition, azathioprine and cyclophosphamide, as it appears less liable to cause important marrow suppression and, unlike cyclophosphamide is not associated with alopecia and haemorrhagic cystitis.     

Temperature-Sensitive Mutants of Murine Leukemia Virus IV. Further Physiological Characterization and Evidence for Genetic Recombination

Several temperature-sensitive mutants of the Rauscher strain of murine leukemia virus representing three distinct physiological groups have been further characterized. Genetic recombination between different pairs of these mutants has been demonstrated. Several representative genetic recombinants were isolated and shown to replicate equally well at the permissive (31 C) and nonpermissive (38 C) temperatures and to have serological characteristics of the wild-type parental virus. Alternative models for the mechanisms involved in recombination between type C RNA viruses are discussed.     

Radioimmunoassay for Avian C-Type Virus Group-Specific Antigen: Detection in Normal and Virus-Transformed Cells

A radioimmunoassay has been developed for detection of avian C-type virus (30,000 mol wt) group-specific (gs) antigen. The method is 10- to 1,000-fold more sensitive than immunological methods previously available. By the radioimmunoassay technique, normal chicken embryo cells, which have previously been classified as gs negative or weakly gs positive, contain clearly detectable amounts of gs antigen. The assay has been used to study the effect of chemical induction and superinfection by mammalian C-type viruses on the expression of avian gs antigen in mammalian cells nonproductively transformed by avian sarcoma viruses.     

Materials for a study in animal competition

The incidence of the sewage fly, Psychoda alternata Say, breeding almost free from other insect competitors in a bacteria bed at Huddersfield is examined. Its general seasonal trend is marked by periods of peak output explained on the theory that there are two successions of generations running persistently and alternating with one another. Such behaviour has previously been demonstrated for another sewage fly, Spaniotoma minima , and has been shown to be instituted by irregular temperatures in autumn and spring. In Psychoda alternata a special type of intraspecific competition is set-up in the warmer months when the cycles are rapid, for the larvae of one succession must start life in a bed just depleted of food by the other. Therefore large and small outbursts of the fly tend to alternate. The discharges of solids from the bed have a detailed periodicity corresponding to the alternations in the successions of the fly.