Differential effects of aldosterone and ADH on intracellular electrolytes in the toad urinary bladder epithelium

Summary Quantitative electron microprobe analysis was employed to compare the effects of aldosterone and ADH on the intracellular electrolyte concentrations in the toad urinary bladder epithelium. The measurements were performed on thin freeze-dried cryosections utilizing energy dispersive x-ray microanalysis. After aldosterone, a statistically significant increase in the intracellular Na concentration was detectable in 8 out of 9 experiments. The mean Na concentration of granular cells increased from 8.9±1.3 to 13.2±2.2 mmol/kg wet wt. A significantly larger Na increase was observed after an equivalent stimulation of transepithelial Na transport by ADH. On average, the Na concentration in granular cells increased from 12.0±2.3 to 31.4±9.3 mmol/kg wet wt (5 experiments). We conclude from these results that aldosterone, in addition to its stimulatory effect on the apical Na influx, also exerts a stimulatory effect on the Na pump. Based on a significant reduction in the Cl concentration of granular cells, we discuss the possibility that the stimulation of the pump is mediated by an aldosterone-induced alkalinization.Similar though less pronounced concentration changes were observed in basal cells, suggesting that this cell type also participates in transepithelial Na transport. Measurements in mitochondria-rich cells provided no consistent results.     

RCA I-binding patterns of the Golgi apparatus

The distribution in the Golgi apparatus of binding sites for the galactose-specific Ricinus communis I lectin (RCA I) was studied in differently specialized cells, including goblet cells and absorptive enterocytes of the rat small intestine as well as acinar cells of the rat embryonic pancreas and submandibular gland. For the purpose of localizing the binding reactions, a pre-embedment method using horseradish peroxidase for electron microscopic visualization, and a post-embedding technique making use of the colloidal gold system were employed. The reactions obtained, localizing cell constituents which contain saccharides with terminal or internal beta-D-galactosyl residues, labeled diverse Golgi subcompartments. The goblet cells showed intense RCA I staining of the cisternae of the trans side of the Golgi stacks. The reaction was weak in the medial cisternae and the cis side of the stacks mostly was devoid of label. In the absorptive cells, in addition to the RCA I reaction of trans Golgi elements, binding sites for this lectin were concentrated in the stacks' medial section. In the embryonic acinar cells, accessible galactosyl residues were either confined to the trans and/or medial cisternae, or distributed across elements of all the stacked saccules. In the latter stacks, the reactions mostly were weak in the cis cisternae and increased in intensity towards the trans side. As regards the respective labeling patterns, similar percentages were calculated for the early and late stages of development: they were approximately 62% for the pattern which showed RCA I label limited to trans/medial cisternae and approximately 38% for the "cis-to-trans"-distributed RCA I reaction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estimation of the mean floristic similarity between and within sets of vegetational relevés

Various possibilities of usingSörensen's coefficient of floristic similarity in plant sociology are summarized. A new formula (11), derived from that bySörensen and based on constancy values, is suggested in order to calculate the mean floristic similarity within a set of relevés.     

Estimation of the mean floristic similarity between and within sets of vegetational relevés

Various possibilities of usingSörensen’s coefficient of floristic similarity in plant sociology are summarized. A new formula (11). derived from that bySörensen and based on constancy values, is suggested in order to calculate the mean floristic similarity within a set of relevés.     

Neue Ergebnisse über die Arbeitshyperthermie des Menschen

Nielsen (1938) demonstrated that hypothermia during exercise is independent of room temperature within a range from 5° to 32° C. Subsequently, other investigators confirmed this observation. From these results,Asmussen &Nielsen (1947) concluded that a resetting of the thermoregulatory centre brought about by impulses reaching the brain from the working muscles or from the motor centres takes place. In order to find out whether impulses from motor centres really affect the thermoregulatory centres, we tried, by administration of curare in human beings, to increase the frequency of impulses necessary to bring about a certain amount of mechanical work. However, in 2 series of experiments at room temperatures of 23° and 34° C respectively and at a constant work output of 3 mkp/sec, no significant differences in body temperature (measured in the lower esophagus) before and during curare infusion could be detected. In the resting conditions, curare exerts no influence on body temperature. In normal subjects performing low work (3 mkp/sec) the body temperature decreases at a room temperature of 23° C but increases at a room temperature of 32° C. In conclusion, the hyperthermia during exercise cannot be due to a resetting of thermoregulatory centres. It works rather like a proportional closed loop control system. The relative independence of the hyperthermia from the environmental temperature suggests a considerable influence of the latter parameter via the thermoreceptors of the skin on the thermoregulation during work.     

Expression of CD44 Splice Variants During Lymphocyte Activation and Tumor Progression

Recently, splice variants of CD44 have been described that confer metastatic potential to non-metastasizing rat pancreatic carcinoma and sarcoma cell lines. Using antibodies against variant CD44 (CD44v) sequences, we have examined the expression of variant CD44 glycoproteins on human lymphoid cells and tissues and in colorectal neoplasia. Lymphohematopoietic cells express low levels of CD44v glycoproteins. During the process of lymphocyte activation in vitro and in vivo, expression of CD44v glycoproteins is transiently upregulated. The reaction pattern of various antibodies indicates that these CD44 variants contain the domain encoded by exon v6, which is part of the variant that confers metastatic capability. In human colorectal neoplasia we observed overexpression of CD44 splice variants in all invasive carcinomas. Already at early stages of colorectal tumor progression exon v5 epitopes were overexpressed. Tumor progression was strongly related to expression of CD44 isoforms containing exon v6 encoded domains. The findings establish CD44 variants as tumor progression markers in colorectal cancer.     

Chromosomal transplantation

Dissociated cells of middle-to-late blastulae were exposed to 0.1 mg colchicine/ml and achieved 92% metaphase arrest. These cells contained a haploid set of Bombina maxima (Anura:Discoglossidae) chromosomes. When transplanted into the enucleated eggs of B. orientalis, some donor cells stimulated development to the late blastula and middle gastrula stages. — Most (17/20) of the embryos resulting from chromosomal transplantation were nonmosaic aneuploids. A high percentage of recipient egg enucleation (93%), the ratio of long-to-short chromosomes, and the presence of species-specific marker chromosomes proved that chromosomes were transplanted from the donor cells. Therefore, metaphase chromosomes lacking intact spindle apparatuses were injected into and incorporated by amphibian eggs. These chromosomes were replicated in all cells of the resulting embryos. The aneuploidy of these embryos is explained by an inability of the recipient egg to locate and replicate many transplanted chromosomes (44%) before first cleavage.     

Alchemilla austriaca,spec. nova,(Rosaceae) — eine neue Art aus den Ostalpen

Alchemilla austriaca is a new species which belongs to the group ofA. demissa, A. frigens, A. longana, A. longiuscula, A. semisecta, andA. sinuata. The holotype specimen as well as leaf and flower details are illustrated (Figs. 1–3). A complete character analysis is given, differences and similarities of allied species are presented in two tables, and the position of the group within the genus is discussed.A. austriaca so far is known only from the Austrian Alps and mainly from the central ranges (distribution map: Fig. 4). Its wet subalpine and alpine habitats are characterized by species lists.

     

Der Einfluss von CCC auf die Entwicklung des Roggenhalmes

Field trials on the effect of chlorocholinechloride (CCC) on rye plants of the cultivar Danae and of a selected population “WRS” proved that rye principally shows as reaction analogous to wheat. The CCC-induced decrease of stalk length is due to the reduction of elongation growth of the 4th internode. This shortening effect is mainly the result of decreased cell extension and, in the middle internode, additionally of inhibited cell division in longitudinal direction. The shape of internodes is changed under the influence of CCC. Walls of parenchyma cells of CCC-treated plants are thinner and those of sclerenchyma cells are thicker compared with cell walls of control plants.