The insensitivity of Vinca rosea to vinblastine

Root tip mitosis in both Vinca rosea and the chosen control Lepidium sativum is susceptible to the effects of colchicine at and above 5×10^–4 M. — Root tip mitosis in L. sativum is susceptible to the effects of vinblastine at concentrations equal to and greater than 10^–4 M, while root tip mitosis in V. rosea, the plant which is the source of vinblastine, is unaffected by exogenously-applied VBL at concentrations up to and including 10^–2 M. — The possible mechanisms by which this resistance of V. rosea to vinblastine might be conferred are discussed.     

High-performance liquid chromatography of p-nitrophenacyl esters of selected prostaglandins on silver ion-loaded microparticulate cation-exchange resin

A silver ion-loaded microparticulate cation-exchange resin column has been used for high-performance liquid chromatographic (HPLC) separation of the p-nitrophenacyl esters of several series of closely related prostaglandins: 8-iso-PGE₂, 11-epi-PGE₂, 5-trans-PGE₂, PGE₂, PGF_1α, PGE₁, and PGF_2α, PGA₂ and PGB₂; 15 (R)-methyl-PGE₂ and 15 (S)-methyl-PGE₂; 5-trans-PGA₂ and PGA₂; and 5-trans-PGF_2α and PGF_2α. The properties of this column are compared with those of silica-gel and reversed-phase columns.     

A fetal skeletal muscle actin mRNA in the mouse and its identity with cardiac actin mRNA

We compare a recombinant cDNA plasmid (pAF81) complementary to a fetal skeletal muscle actin mRNA with a plasmid (pAM91) complementary to the actin mRNA expressed in adult skeletal muscle. The two mRNAs are significantly diverged in silent nucleotide positions; they are coexpressed in fetal skeletal muscle, and in differentiating muscle cell cultures their accumulation begins coordinately. The sequence of pAF81 shows that the amino acid sequence of mouse fetal skeletal muscle actin is almost identical to that of adult bovine cardiac actin. Hybridization of pAF81 to RNA from different mouse tissues shows that fetal skeletal muscle actin mRNA is very homologous or identical to fetal and adult cardiac actin mRNA. Only one gene homologous to pAF81 is detected on blots of restricted mouse DNA. We conclude that this gene must be expressed both in fetal skeletal muscle and in fetal heart. Whereas mRNA transcribed from this gene is the major actin mRNA species in adult heart, it is present in low amounts, if at all, in adult skeletal muscle.     

Pituitary corticotropin-inhibiting peptide: Properties and use in study of corticotropin action

The biological properties of the naturally occurring pituitary peptide α_h^7–38-adrenocorticotropin (ACTH) have been investigated. α_h^7–38-ACTH is devoid of steroidogenic activity but inhibits competitively ACTH-induced steroidogenesis in vitro as well as in vivo. The long-term actions of ACTH on normal and tumor adrenal cells in culture are also antagonized by α_h^7–38-ACTH. The apparent K_i for the inhibition of cyclic AMP production by α_h^7–38-ACTH (301 ± 62 nm) was significantly higher than the apparent K_i for the inhibition of corticosterone synthesis (21.6 ± 6.8 nm). Analysis of the inhibition of ACTH-induced steroidogenesis and cyclic AMP production in normal rat adrenocortical cells indicates that two separate receptors may be involved in mediating these responses.     

Theory of lipid bilayer phase transitions as detected by fluorescent probes

Summary We present a quantitative theory that relates the fluorescence intensityvs. temperature (I vs. T) profile of a fluorescent-labeled two-component lipid bilayer to the phase diagram of the bilayer and the partition coefficientK of the fluorophore between fluid and solid phases of the bilayer. We show how the theory can be used to evaluateK from experimentalI vs. T profiles and the appropriate phase diagrams as well as to understand the different shapes ofI vs. T profiles obtained with particular fluorophores and phase diagrams. Using calculatedI vs. T graphs, we discuss the meaning of parameters, such as midpoint of the phase transition and onset and termination of a transition, which are often used to characterize phase transitions on the basis of fluorescence intensityvs. temperature profiles.     

Influence of N and K fertilization and growth temperature on 13C/12C ratios of timothy (Phleum pratense L.)

Summary Measurements have been reported of carbon isotope ratios of timothy grown at different temperatures and with varying nitrogen and potassium supplies. Both total plant tissue and extracted plant tissue have been analyzed. The ¹³C/¹²C ratios were found to vary both with temperature and with nutrient level; the highest values of ¹³C were found under the most optimum growth conditions.     

Cell free synthesis of some storage protein subunits by polyribosomes and RNA isolated from developing seeds of pea (Pisum sativum L.)

Polyribosomes which have template activity in the wheat germ system have been isolated from developing pea seeds. Some of the translation products have identical mobilities to the vicilin and legumin subunits by SDS-PAGE. Certain products were specifically immunoprecipitated with antisera prepared against purified vicilin and legumin fractions. Various RNA fractions including poly A-rich RNA have also been isolated from polyribosomes and shown to direct the synthesis of polyripeptides whose properties are similar to the storage protein subunits. The results are discussed in relationship to other investigations with seed storage protein biosynthesis in vitro.Abbreviations DTT dithiothreitol - SDS-PAGE SDS-polyacrylamide gel electrophoresis - TCA tricarboxylic acid     

Japanese psychotherapeutic systems: On acceptance and responsibility

Summary Pelzel (1977: 299) pointed out in a previous issue of this journal how most psychiatric care in Japan is heavily oriented towards pharmacological intervention and takes place in mental hospitals. Moreover, there has been an increase in the number of beds set aside for psychiatric care (Ikegami 1980). The quiet therapies and traditional EastAsian medicine, though flourishing, are not representative of health care for the majority of the population of Japan today.I believe that a preference for pharmacological intervention in psychiatric care is not surprising in light of the above discussion on somatopsychics and the primacy of group harmony. What is badly wanted now are contemporary anthropological studies on the application of biomedicine in Japan (Long 1980, has made an excellent beginning) to give some perspective to the more esoteric studies already undertaken, to demonstrate cross-cultural differences in the application of biomedicine, and to look for continuities of thinking and behavior across all therapeutic systems in Japan. Only then can we extrapolate from these studies to statements about the relationship of therapeutics to Japanese society at large, and about the recurrent question of pluralistic forms of health care in industrial societies.