Development of a rapid chromatographic strip test for the pen-side detection of foot-and-mouth disease virus antigen.

Foot-and-mouth disease (FMD) is the most contagious animal virus disease of cloven-hoofed livestock and requires reliable and accurate diagnosis for the implementation of measures to control effectively its spread. Routine diagnosis of FMD is carried out at the OIE/FAO World Reference Laboratory for Foot-and-Mouth Disease (WRL for FMD), Pirbright by the combined use of ELISA and virus isolation in cell culture supplemented by reverse transcription polymerase chain reaction (RT-PCR) methods. These techniques require skilled personnel and dedicated laboratory facilities which are expensive. The development of a rapid and simple test for the detection of FMD virus antigen using Clearview chromatographic strip test technology for field application is described. This device detected FMD viral antigen in nasal swabs, epithelial suspensions and probangs from clinical samples submitted from the field, from animals infected experimentally and in supernatant fluids resulting from their passage in cell culture. The test system was more sensitive than ELISA for the diagnosis of all seven serotypes of FMD virus in the epithelial suspensions and nasal swabs and had equivalent sensitivity to the ELISA for the detection of contemporary virus strains in cell culture supernatant fluids. The study demonstrated the potential for this device to confirm a clinical diagnosis at the site of a suspected FMD outbreak, thereby offering the possibility of implementing control procedures more rapidly. Such pen-side diagnosis would have particular benefits in FMD emergencies, relevance to FMD control programmes which operate in endemic regions of the world such as South East Asia and for increasing disease awareness in other areas where efforts to control disease may be difficult. In each circumstance the availability of a pen-side device for diagnosis would reduce the necessity for sending routine diagnostic samples to an FMD laboratory and thereby reduce the delay in diagnosis, which can in some areas be considerable.

Uptake of L-DOPA by the cells of organotypic culture from chick-embryo brain hemispheres.

With the use of the histofluorescence method investigations were performed on L-DOPA uptake by the cells of an organotypic culture from chick-embryo brain hemispheres and newborn rats. It has been found that in chick-embryos between the 8th to 11th day of development and 5 to 14 days in culture in vitro, with a concentration of 0.1 mg/10ml of L-DOPA applied to the culture, intense fluorescence in cell membranes, perinuclear region and sometimes in the whole cell body and the initial parts of the cell processes can be observed. It is supposed that in the stage of development of chick-embryos and newborn rats under study neural elements and glial cells take up the amino-acid applied. The authors suggest that the uptake of L-DOPA proceeds rather through the uptake II mechanism.

Culture of nervous tissue from rats of various age for some pharmacological studies.

Explants of nervous tissue from locus coeruleus of rats 30-40 days old grow in the tissue culture similarly well as the explants from embryos or newborn rats under the same culture conditions. This material may be employed particularly for investigation of the action of drugs on central monaoaminergic process, as after the 30th day of the postnatal life essential monoaminergic mechanisms in the brain are already fully developed, and endogenous noradrenaline is present in the neural cells.

The effect of drugs on accumulation of exogenous norepinephrine by nervous tissue in vitro.

The effect of hydrocortisone and prednisone on accumulation of exogenous norepinephrine was tested in nervous tissue in vitro, taken from rats at various periods of the postnatal life. The results indicate that exogenous norepinephrine is taken up by either uptake1 or uptake2 or both, depending on the age of explant donors and the kind of the cell. Uptake1 appearing predominantly in the tissue from young animals, in first days of postnatal life, differs from the uptake2 in the cardiac muscle in that it is inhibited by hydrocortisone, inactive in this respect in the heart.

The influence of pharmacological agents on the accumulation of egzogenic noradrenalin in nervous tissue cultivated in vitro. I. Effect of desipramine.

The authors investigated absorption of noradrenalin by neurons and glia cells cultivated in vitro. Material was taken from locus coreuleus of 3, 6, 12, 18, 24, and 36 days old rats. On the basis of observations, the authors found out that absorption of egzogenic noradrenalin changes with the growth of animals. In animals less than 24 days old, noradrenalin is absorbed not only by neurons but also by glia cells. Desipramin affects the egzogenic noradrenalin absorption clearly over the 12th day of life.

The effect of drugs on accumulation of exogenous norepinephrine in nervous tissue cultured in vitro. IV. The effect of clonidine.

Explants of nervous tissue taken up from the area of locus coeruleus from rats 3-36 days old were cultured in vitro for 15 days, and than accumulation of norepinephrine (3 X 10-8M) was studied with and without preincubation with equimolar concentration of clonidine, using histofluorescence methods. Preincubation with clonidine increased the fluorescence in neural cells, particularly those derived from young animals, in which the pattern of fluorescence appeared to resemble the observed without preincubation only in cells from older animals in addition to fluorescence in the cells, fluorescent granules appeared in neuronal processes and in structures resembling non adrenergic nerve endings. Clonidine completely inhibited norepinephrine uptake by glial cells from very young animals, and inhibited that in the glia in colonies derived from 18-24 days old rats. However, clonidine preincubation restored accumulation of norepinephrine by oligodendroglia from 36 days old rats already lost by this age, but did not affect astrocytes.