The copolymeric structure of pig skin dermatan sulphate. Isolation and characterization of l-idurono-sulphate-containing oligosaccharides from copolymeric chains

Dermatan sulphate was degraded by testicular hyaluronidase and an oversulphated fraction was isolated by ion-exchange chromatography. This preparation, which contained fairly long segments derived from the non-reducing terminal portion of the molecule, was subjected to periodate oxidation under acidic conditions. The oxidized iduronic acid residues were cleaved by reduction-hydrolysis (Smith-degradation) (Fransson & Carlstedt, 1974) or by alkaline elimination. The oligosaccharides so obtained contained both GlcUA (glucuronic acid) and IdUA-SO(4) (sulphated iduronic acid) residues. Copolymeric oligosaccharides obtained after alkaline elimination were cleaved by chondroitinase-AC into disaccharide and higher oligosaccharides. Since the corresponding oligosaccharides obtained by Smith-degradation were unaffected by this enzyme, it was concluded that the carbohydrate sequences were GalNAc-(IdUA-GalNAc)(n)-GlcUA-GalNAc. The iduronic acid-containing sequences were resistant to digestion with chondroitinase-ABC. It was demonstrated that the presence of unsulphated N-acetylgalactosamine residues in these sequences could be responsible for the observed effect. This information was obtained in an indirect way. Chemically desulphated dermatan sulphate was found to be a poor substrate for the chondroitinase-ABC enzyme. Moreover, digestion with chondroitinase-ABC of chondroitinase-AC-degraded dermatan sulphate released periodate-resistant iduronic acid-containing oligosaccharides. It is concluded that copolymeric sequences of the following structure are present in pig skin dermatan sulphate: [Formula: see text] N-acetylgalactosamine moieties surrounding IdUA-SO(4) residues are unsulphated to a large extent.     

Synchronization of Oestrus in Heifers with Norethisterone

Sixty-five heifers in different stages of the oestrus cycle were fed norethisterone once daily for 17 days at doses of 0.2, 0.6 and 1.0 mg/kg body weight. During treatment swollen vulva, mucus discharge, open and reddened portio and udder enlargement were noted. Norethisterone was effective in suppressing oestrus and ovulation at doses of 0.6 and 1.0 mg/kg. Extremely good heat-synchronization followed the treatment and 98 % of the heifers came on heat within a two-day period. Fifty-five % conceived after the first insemination. In the group receiving 0.2 mg norethisterone per kg, three out of 13 heifers showed psychic heat during treatment. Poor heat synchronization and low conception rate were obtained in this group. A possible effect of cycle stage on heat synchronization was noted only in the 0.2 mg group where a better result was obtained when treatment began in the follicular phase.     

Observations on the cellular localization of dopamine in the caudate nucleus of the rat

Summary The cellular localization of dopamine in the caudate nucleus of the rat hat been studied with the highly sensitive and specific fluorescence method of Falck and Hillarp, and by electron microscopy. The histochemical studies provided strong support for the view that the dopamine is concentrated within very fine nerve fibres which have abundant varicosities with an intense fluorescence. The electron microscopical studies revealed the presence of a tightly packed plexus built up i.a. of abundant synaptic nerve terminals, many of which had a diameter below 0.4 . The terminals made synaptic contact mainly with processes that seemed to belong to an extensive dendrite net.The investigation was supported by research grants from the United States Public Health Service (02854-04), The Swedish Medical Research Council and the Knut and Alice Wallenberg Foundation.     

Reversed-phase liquid chromatographic determination of idarubicin and its 13-hydroxy metabolite in human plasma

A method is given for the determination of idarubicin and its main metabolite, idarubicinol, in plasma from cancer patients. Idarubicin and idarubicinol are extracted from 2-ml samples of buffered plasma (pH 8.1) using chloroform-1-heptanol (9:1). After reextraction into phosphoric acid (0.1 M), separation is performed by reversed-phase liquid chromatography on a LiChrosorb RP-2 column (5 μm) with a mobile phase of acetonitrile-water, acidified with phosphoric acid. The absolute recovery in the range 5–100 ng/ml was greater than 83% with a precision better than 8% (relative standard deviation), using photometric detection at 484 nm. Proper handling of whole blood samples containing idarubidin is essential to avoid metabolic conversion into idarubicinol. Prolonged storage of the drug and its main metabolite under alkaline conditions should be avoided to prevent chemical degradation.     

Effects of plant odor on oviposition by the black swallowtail butterfly,Papilio polyxenes (Lepidoptera: Papilionidae)

Black swallowtail females laid more eggs on plant models treated with contact stimulants and volatiles from carrot leaves than on models treated only with contact stimulants. The volatiles enhanced landing rates and females alighted more frequently on artificial leaves treated with host volatiles than on adjacent control leaves. Volatiles from cabbage, a nonhost, inhibited landing rates on artificial leaves treated with carrot contact stimulants. Examination of antennae revealed two major types of sensilla, believed to be olfactory in function. Electroantennogram preparations responded more strongly to carrot volatiles than to cabbage volatiles and several shared responses at particular retention times to carrot volatile components eluting from a gas chromatograph. Our results are consistent with a long-standing hypothesis that behavioral responses to essential oil components characteristic of the larval food plants have facilitated host shifts in the genus Papilio.     

Trapping a local population of spruce bark beetles Ips typographus (L.): Population size and origin of trapped beetles

A method of trapping local populations of Ips typographus was investigated in the field. The size of a population emerging from a hibernation site in the forest litter was estimated using tent traps. This estimate was compared with another estimate where beetles from the population were marked and recaptured in pheromone traps. The estimate of population size with mark-recapture was much higher than the estimate with tent traps, indicating a high degree of immigration. According to calculations only a minor part (less than 20%) of the beetles caught in the pipe traps originated in the local population. Re-emerging parent-adults were marked and released during the second flight period. The recapture rate was 29.8%, almost the same as during the first flight. Immigration during the first and second flight periods was estimated to be of similar magnitude. The results show that it is difficult to suppress local populations of highly mobile bark beetles by trapping.     

Relative positions of some epitopes on carcinoembryonic antigen

Summary To investigate whether anti-(carcinoembryonic antigen) monoclonal antibodies (mAb) react with single or repeated epitopes, sandwich radioimmunoassays in homologous and heterologous combinations were performed. Four mAb (I-27, I-47, II-17 and to some degree II-16) gave homologous binding while two mAb (I-38S1 and II-10) did not. Taken together with previous immunoprecipitation studies we conclude that all these mAb except II-10 react with repeated epitopes. The relative positions of the epitopes recognized by these mAb and of three additional mAb (II-6, II-7 and CB-CEA-1) were investigated using a plate antibody competition test with enzyme-labelled carcinoembryonic antigen (CEA). mAb I-38S1, II-6, II-7, II-10, II-16 and CB-CEA-1 were mutually cross-reactive, and were classified as belonging to one epitope group. mAb I-27 and I-47 fell outside this group and did not interfere with the binding of CEA conjugate to mAb II-17 either. They therefore represent a second epitope group. mAb II-17 showed no interference with the binding of CEA to any of the other mAb and must therefore represent a third epitope group. The slopes of the plate antibody competition curves were used for calculation of a correlation matrix, which in turn was used to depict the relative positions of the epitopes recognized by the mAb in the large group.     

Iodide transport in primary cultured thyroid follicle cells: evidence of a TSH-regulated channel mediating iodide efflux selectively across the apical domain of the plasma membrane.

The transport of iodide was studied in porcine thyroid follicle cells cultured in bicameral chambers. The continuous layer of polarized follicle cells, joined by tight junctions, formed a diffusion barrier between the two compartments (apical and basal) of the culture chamber. Uptake and efflux of 125I- at either surface (apical and basolateral) of the cells were thus possible to determine. Protein binding of iodide was inhibited by methimazole (10(-3) M) in all experiments. Radioiodide was taken up by the cells from the basal medium in a thyroid-stimulating hormone (TSH)-dose dependent manner with a maximal cell/medium ratio of 125I- of about 50 in cultures prestimulated with 0.1 to 1 mU/ml for 2 days. This uptake was inhibited by perchlorate and ouabain. In contrast, 125I- was not taken up from the apical medium. In preloaded cells, iodide efflux was rapidly (within 1-2 min) and dose-dependently (0.1-10 mU/ml) stimulated by TSH. Bidirectional measurements revealed that TSH stimulated iodide efflux in apical direction, leaving efflux in basal direction unchanged. In experiments with continuous uptake of label from the basal compartment, the TSH-stimulated efflux in apical direction had a duration of 4 to 6 min and resulted in a reduction in the cellular content of radioiodide by up to 80%. Decreased levels of cellular 125I- remained for at least 15 min after TSH addition. From our observations we conclude that the TSH-regulated uptake and efflux of iodide take place at opposite surfaces of the porcine thyroid follicle cell. Acutely stimulated iodide efflux is not the result of an increased permeability for iodide in the entire plasma membrane but only in the apical domain of this membrane. This implicates the presence of an iodide channel mediating TSH-stimulated efflux across the apical plasma membrane of the follicle cell. The mechanism is suggested to facilitate a vectorial transport of iodide in apical direction, i.e., to the lumen of the intact follicle.