Theoretical study of a two-dimensional autocatalytic model for calcium dynamics at the extracellular fluid-bone interface

The temporal behaviours of the nonlinear substructure of a self-organized compartmental model of calcium metabolism were investigated. The order-two autocatalytic process included in this simple two-dimensional model is compared to some secondary nucleation mechanisms which should take place at the extracellular fluid-bone interface. The model gives rise to complex dynamic behaviours, and multistability properties, involving up to two stable periodic regimes (birhythmicity), were established in different topological configurations. The bifurcations occurring on the boundaries between regions of different qualitative behaviour have been determined. These properties are discussed in relation to the dynamical behaviour of other two-variable models, especially those including the same nonlinearity.     

Tissue specific expression of the acetylcholinesterase gene in Drosophila melanogaster

Summary Acetylcholinesterase (AChE) is mainly membrane bound in the central nervous system (CNS) of larvae and in the head and thorax of adults of Drosophila melanogaster; it is mostly soluble in the larval carcass, the adult abdomen, similar to that of the embryos (Zador et al. 1986). The enzyme shows the same number of isozymes (four or five) in larvae and adults as in the head of the fly or in embryos (Zador et al. 1986). In the Df(3R)GE26/MKRS stock both the membrane bound and the soluble enzyme are at about half normal levels while in the Df(3R)Ace ^HD1/MKRS stock this is true only for the membrane bound AChE. Therefore the effect of the above deficiencies in larvae and adults is consistent with that in embryos (Zador et al. 1986). In heat-sensitive combinations of certain Ace mutant alleles both the membrane bound and the soluble enzyme has reduced activity.Abbreviations AChE acetylcholinesterase (acetylcholine acetyl hydrolase, EC 3.1.1.7) - BAP 1,5-bis(allyldimethylammonium-phenyl)-pentan-3-one dibromide - CNS central nervous system     

Genetic diversity in Cucumis sativus L. assessed by variation at 18 allozyme coding loci

Summary The genetic diversity of the U.S. Cucumis sativus L. germplasm collection [757 plant introductions (PI) representing 45 countries] was assessed using 40 enzymes which represented 74 biochemical loci. Polymorphisms were observed at 18 loci (G2dh-1, Gpi-1, Gpi-2, Gr-1, Gr-2, Idh, Mdh-1, Mdh-2, Mdh-3, Mpi-2, Pepla-2, Peppap-2, Per-4, Pgd-1, Pgd-2, Pgm-1, Pgm-3, and Skdh). Two PIs (285606 and 215589) contained alleles [G2dh-1(1) and Per-4(2), respectively] which did not occur in any other PI. Other alleles which occurred in low frequencies (in < 1% of the PIs) included Gpi-1(3), Gpi-2(3), Gr-1(3), Gr-2(1), Idh(1), Mdh-1(2), Mdh-2(1), Peppap-2(1), and Pgd-1(1). Individual loci containing more than one allele in greater than 20% of the PIs included Mpi-2, Pepla-2, Pgd-2, and Pgm-1. Multivariate analyses aided in the reduction of data (principle components), depicted relationships among PIs (cluster), and identified the most discriminating enzyme loci (Pgm-1, Pepla-2, Gr-1, Pgd-2, Mpi-2, and Skdh) (classification and regression tree).Research partially supported by Asgrow, DeRuiter, Nickerson-Zwaan, Nunhems, and Sun Seed Companies; and the Graduate School, University of Wisconsin, Madison     

Cellular regulation of ADP-ribosylation of proteins. III. Selective augmentation of in vitro ADP-ribosylation of histone H3 in murine thymic cells after in vivo emetine treatment

Thymic cells were isolated at intervals of between 0 and 144 h from mice that received one intraperitoneal injection of emetine (33 mg/kg), and thymus weight, incorporation of [14C]leucine into proteins and [3H]thymidine into DNA in intact thymic cells, as well as initial rates of protein ADP-ribosylation in permeabilized cells [A. Sóoki-Tóth, F. Asghari, E. Kirsten, and E. Kun (1987) Exp. Cell Res. 170, 93] were simultaneously monitored. The effect of emetine as an inhibitor of protein synthesis [F. Antoni, N. G. Luat, I. Csuka, I. Oláh, A. Sóoki-Tóth, and G. Bánfalvi (1987) Int. J. Immunopharmacol. 9, 333] corresponds to the induction of sequential cellular events, such as cell exit and remigration, by other antimitotic agents [C. Penit and F. Vasseur (1988) J. Immunol. 140, 3315] and produces an activation of proliferation of cells reentering into this organ. Proliferation, as demonstrated by a large increase in DNA synthesis and entrance into S phase, was kinetically related to an apparent increase in poly(ADP-ribose) polymerase activity in thymic cells and a highly significant in vitro ADP-ribosylation of histone H3. Since no DNA fragmentation occurred in thymic cells, as tested by a fluorometric technique [C. Birnboim and J. J. Jevac (1981) Cancer Res. 41, 1889], it is probable that a selective activation of poly(ADP-ribose) polymerase may have been induced in cells that undergo differentiation and proliferation while repopulating the thymus.     

The HeLa cell protein TEF-1 binds specifically and cooperatively to two SV40 enhancer motifs of unrelated sequence

We have purified a protein (TEF-1) that specifically binds to two sequence unrelated motifs (GT-IIC and Sph) of the simian virus 40 (SV40) enhancer. TEF-1 binds cooperatively to templates containing tandem but not inverted or spaced repeats of its cognate motifs. This cooperative binding correlates with the ability of the tandem repeats to generate enhancer activity in vivo. In contrast, TEF-1 and a second SV40 enhancer binding protein, TEF-2, bind independently to templates containing the cognate motifs of both proteins (GT-I and either GT-IIC or Sph motifs) even though these motifs cooperate in enhancer activity in vivo. These results allow us to distinguish different classes of enhancer factors.     

Filtration profile in isolated zone 1 and zone 3 dog lungs at constant high alveolar pressure

We measured the rate of liquid filtration in isolated dog lung lobes inflated to a constant alveolar pressure of 25 cmH2O and with all open vessels filled with plasma. We measured lung weight gain at vascular pressures ranging from 5 to 40 cmH2O relative to pleural pressure. We confirmed that under zone 1 conditions the "arterial" and "venous" extra-alveolar segments have essentially the same filtration characteristics. Using the combined extra-alveolar vascular system, we determined when recruitment of filtration surface area occurred as we increased vascular pressure from 0 to 40 cmH2O. Based on an abrupt increase in filtration rate as vascular pressure approached the zone 1/3 boundary, we infer that a sudden recruitment of exchange surface area occurred at that point. Based on the slopes of the zone 1 and zone 3 filtration profiles, we conclude that extra-alveolar vascular segments contribute approximately 25% of total to filtration in the lung under zone 3 conditions, although the exact vessels filtering under zone 1 conditions have yet to be determined. Our analysis of the data supports the concept that there is a difference in the perimicrovascular pressure around alveolar and extra-alveolar vessels, which in part may account for the apparent high filtration fraction apportioned to extra-alveolar vessels.     

Characterization and Identification of Caprine,Genital Mycoplasmas

A total of 55 mycoplasma strains, isolated from the vagina of goats, were examined. Three strains, being arginine positive and glucose negative, could not be finally classified. Five isolates were identified as Acholeplasma laidlawii. Fourty-seven strains were phosphatase positive, glucose and arginine negative. Nine of these formed “film and spots” on standard growth medium, and reduced tetrazolium aerobically. Serological examination identified 7 as M. agalactiae, while 2 were M. bovis. The remaining 38 isolates did not reduce tetrazolium aerobically, and did not produce “film and spots.” on standard growth medium. All these except one were identified as M. bovigenitalium by immunofluorescence. Their relationship to group 11 otf Al-Aubaidi is discussed.     

Intrathoracic sources of caudal mediastinal lymph node efferent lymph in sheep

We investigated the intrathoracic contributions to the caudal mediastinal lymph node (CMN) efferent lymph in 12 anesthetized sheep after removing possible systemic contributions from below the diaphragm. We interrupted various pathways that may send lymph to the CMN (chest wall, esophagus, lung). Because the experiment is destructive, we did the resections in various combinations and waited 1 h between steps. Base-line CMN efferent lymph flow averaged 0.90 +/- 0.52 g/15 min (mean +/- SD). Cutting the pulmonary ligaments bilaterally caused lymph flow to decrease by an average of 58%. In five sheep, cauterizing around the lung hila reduced lymph flow by 16% of base line, cauterizing along the esophagus reduced lymph flow by 18% of base line, and cauterizing along the chest wall increased lymph flow by 6% of base line. After complete isolation of the node, except for the bronchoesophageal artery, dorsal mediastinal vein, and CMN efferent duct, 14% of base-line flow remained. The lymph-to-plasma total protein concentration ratios did not change significantly with any procedure. Under the conditions of our experiments, approximately 74% of base-line intrathoracic CMN efferent flow comes from the lung.     

Large granular lymphocytes,Leu 7 reactivity and natural killer cell function in peripheral blood of patients with Hodgkin's disease

Summary The percentage and absolute number of lymphocytes and Leu 7⁺ cells were significantly lower in HD even in active stages. There was no significant difference in the percentage of LGL between the three groups (control, active HD, inactive HD), however, because of differences in counts of lymphocytes the absolute number of LGL was significantly lower in HD even in the active group than that in healthy controls. The absolute count of LGL and Leu 7⁺ cells in patients in remission was significantly higher than that in active HD. Natural cytotoxicity against K-562 cells was also significantly lower in active patients in comparison with controls, while the percentage of cytotoxicity was slightly but not significantly higher in patients in remission than that in the active group. A positive correlation was observed between all the three examined parameters both in controls and in patients with active and inactive HD.