Laboratory investigation and infection control of cholera in Kingston,Ont.

Vibrio cholerae, biotype El Tor, was isolated in a hospital laboratory in Kingston, Ont. in 1974. Confirmation and complete identification by the Ontario regional and provincial public health laboratories was obtained within 3 days. Institution of well established infection-control and public health measures prevented spread of the infection within the hospital and the community.     

Thyrotropin-releasing hormone (TRH) analogues show enhanced CNS selectivity because of increased biological stability

TRH exerts both endocrinological and neuropharmacological actions. Two analogues of TRH, Pyr-His-Mep . NH2 (L-trans-3-methylprolineamide) and Pyr-His-Dmp . NH2 (L-3,3-dimethylprolineamide) have been examined for their neuropharmacological and endocrinological effects. Comparisons of their ability to provoke hyperthermia in rabbits demonstrated that both analogues were more potent than TRH, but like the parent peptide had only a limited ability to cross the blood brain barrier. This conclusion was confirmed by whole body autoradiographical studies. In contrast both analogues had a similar potency to TRH with respect to the ability to provoke TSH release. It is concluded that the increased potency in neuropharmacological tests results from enhanced bioavailability to CNS sites and that a similar rationale can be used to explain the CNS selectively claimed in the literature for other analogues of TRH.     

Monoclonal antibodies directed against protoplasts of soybean cells

Splenocytes, derived from mice that had been immunized with protoplasts prepared from suspension cultures of root cells of Glycine max (L.) Merr. (SB-1 cell line), were fused with a murine myeloma cell line. The resulting hybridoma cultures were screened for the production of antibodies directed against the soybean protoplasts and were then cloned. One monoclonal antibody, designated MVS-1, was found to bind to the outer surface of the plasma membrane on the basis of several criteria: (a) agglutination of the protoplasts; (b) binding of fluorescence-labeled immunoglobulin on protoplasts yielding a ring staining pattern with prominent intensity at the edges; and (c) saturable binding by protoplasts of ¹²⁵I-labeled Antibody MVS-1. The antigenic target of Antibody MVS-1, identified by immunoblotting techniques, contained a polypeptide of relative molecular mass (M_r) approx. 400000 under both reducing and non-reducing conditions. When the antigenic target of Antibody MVS-1 was chromatographed in potassium phosphate buffer, the position of elution corresponded to that of a high-molecular-weight species (M_r 400000). These results provide the protein characterization required for the analysis of the mobility of Antibody MVS-1 bound to the plasma membrane of SB-1 cells.Abbreviations D diffusion coefficient - M_r relative molecular mass - PBS phosphate-buffered saline (8.00 g NaCl, 1.15 g Na₂HPO₄, 0.20 g NaH₂PO₄ per 1 L, pH 7.2) - TPBS phosphate-buffered saline containing 0.5% Tween-20 - TX-100, TX-114 Triton X-100, X-114 - SDS sodium dodecyl sulfate     

Insulin binding to skeletal muscle microsomes in lactating and dry sheep

Microsomes were prepared from skeletal muscles taken from lactating and non lactating ewes. Insulin binding to these microsomes was not affected by reproductive status. There were significant differences in the ability of individual muscles to bind insulin. These differences correlated with the function of the muscle, as defined by the predominant muscle fibre type.     

Purification and characterisation of the in vitro colony forming cell in monkey hemopoietic tissue

Buoyant density gradient separation of Rhesus monkey bone marrow, spleen and blood leukocytes has demonstrated a reproducible and homogeneous light density distribution profile of cells capable of forming hemopoietic colonies in agar culture (in vitro colony forming cells — CFC). High resolution density gradient separation performed on a light density fraction of bone marrow produced on average a 100-fold enrichment of in vitro CFC with the most enriched fractions containing the majority of the in vitro CFC population present in the original marrow. Fractions were routinely obtained in which up to 23% of cells formed colonies and 33% were capable of proliferating to some degree upon stimulation. Tritiated thymidine suiciding showed the active proliferative status of the in vitro CFC and application of autoradiography and morphological characterisation to highly enriched density fractions has shown that the in vitro CFC in normal marrow is a transitional lymphocyte. Single cell transfer experiments have shown that in vitro CFC's formed colonies containing both granulocytes and macrophages, formally demonstrating the clonal origin of in vitro colonies and the common origin of granulocytes and macrophages.     

Hemopoietic regulators.

The production and maturation of blood cells from the eight major blood cell lineages is a complex and continuous process, which is largely controlled by specific glycoprotein hemopoietic regulators. These regulators also control the functional activity of the blood cells through eliciting a diverse set of intracellular responses initiated by a regulator-specific membrane receptor. Twenty of these regulators have now been characterized, and their mass production has led to four already being licensed for clinical use in disease states involving subnormal blood cell formation.