Thymosin beta4 enhances endothelial cell differentiation and angiogenesis

When human umbilical vein endothelial cells (HUVEC) differentiate into capillary-like tubes, there is a five-fold upregulation of the mRNA for thymosin beta4 (Tbeta4) (Grant et al. J Cell Sci 1995; 108: 3685-94 [1]) and this endogenous expression plays an important role in endothelial cell attachment to and spreading on matrix components. We now show that exogenous addition of thymosin beta4 (in the ng-microg range) to HUVEC in culture can induce several biological responses. These responses include increased tube formation in vitro. Additionally, exogenous thymosin beta4 enhances vascular sprouting in the coronary artery ring angiogenesis assay. Measurements of these vascular sprouts show a doubling of the vessel area (via increased branching) with as little as 100 ng of synthetic thymosin beta4. These processes appear to involve the binding of thymosin beta4 to an unknown cell surface receptor and internalization of the protein. This cell surface-binding appears not to be mediated through the thymosin beta4-actin binding domain LKTET. An increase in thymosin beta4 cytoplasmic staining in HUVEC exposed 10 microg of the peptide appears to occur without increased mRNA translation. In summary Tbeta4 induces an increase in cell-matrix attachment, proliferation, tube formation, internalization of the peptide and rearrangement of the actin cytoskeleton. The data now defines both an autocrine and paracrine role for thymosin beta4 in vessel formation.

Three-Dimensional Ultrastructural Karyotype Analysis from the Meiotic Parthenogenetic Nematode Heterodera betulae

Meiotic chromosome structure and function are described in the plant-parasitic nematode Heterodera betulae. Twelve synaptonemal complexes (SCs) were reconstructed from pachytene nuclei; therefore, n=12 is predicted for this species. Morphologically distinct sex chromosomes were not observed. Only one end of the SC is attached to the nuclear envelope, and there is no bouquet arrangement at pachytene. The structure of the SC in this meiotic parthenogenetic nematode was different than in other nematodes that reproduce via amphimixis; a striated central element with transverse filaments was not observed. Multiple SCs, or polycomplexes, were present in the nucleus. Recombination nodules were not observed. The centrioles were comprised of nine doublet microtubules connected by a ring, which is a distinct modification from the typical nine triplet microtubules without any interconnecting structure.

Meiotic Structures in the Animal-Parasitic Nematode Ascaris megalocephala: Synaptonemal Complexes, Recombination Nodules, and Centrioles

Two synaptonemal complexes (SCs) were present in the pachytene nuclei of Ascaris megalocephala. The SC was tripartite and comprised of two lateral elements (25 nm) with a striated central element (25 nm) and a central region of 65 nm. Spherical recombination nodules were observed to be associated only with the central element, although they are non-existent in the related A. lumbricoides var. suum (Goldstein, 1977). The SCs were attached to the nuclear envelope at only one end, while the other end was free in the nucleoplasm. This lack of bouquet formation of the chromosomes is consistent with all other nematodes studied. Morphologically distinct sex chromosomes were not observed, which differs from the presence of five Y-chromosomes present in A. lumbricoides var. suum (Goldstein and Moens, 1976). Centrioles (0.2 microm wide) reproduced by budding off the parental centriole. The centrioles consisted of nine singlet microtubules connected by an electron-dense proteinaceous ring. This structure is consistent with centrioles described in other nematodes, yet distinctly different from the centriole structure observed in most organisms in which it consists of nine triplet microtubules without any connecting ring. Multiple synaptonemal complexes, or polycomplexes, are found in A. megalocephala and A. lumbriocoides var. suum. They appear as stacked SC and are present inside the nucleus during zygotene and in the cytoplasm at pachytene.

Research on the metabolic engineering of the direct oxidation pathway for extraction of phosphate from ore has generated preliminary evidence for PQQ biosynthesis in Escherichia coli as well as a possible role for the highly conserved region of quinoprotein dehydrogenases

The ability of some bacteria to dissolve poorly soluble calcium phosphates (CaPs) has been termed 'mineral phosphate solubilizing' (MPS). Since most microorganisms and plants must assimilate P via membrane transport, biotransformation of CaP into soluble phosphate is considered an essential component of the global P cycle. In many Gram-negative bacteria, strong organic acids produced in the periplasm via the direct oxidation pathway have been shown to dissolve CaP in the adjacent environment. Therefore, the quinoprotein glucose dehydrogenase (PQQGDH) may function in the ecophysiology of many soil bacteria. There is interest in using MPS bacteria for industrial bioprocessing of rock phosphate ore (a substituted fluroapatite) or even for direct inoculation of soils as a 'biofertilizer' analogous to nitrogen fixation. Our laboratory has spent 20 years studying superior MPS bacteria. Screening genomic libraries in the appropriate E. coli genetic background can 'trap' PQQ or GDH genes from these bacteria via functional complementation. In setting the 'trap' for PQQ genes, we have identified DNA fragments that apparently induce PQQGDH activity in E. coli with no sequence homology to known PQQ genes. These data suggest that E. coli may have an alternative, inducible PQQ biosynthesis pathway. Finally, a novel protein engineering strategy to increase the catalytic rate of PQQGDH has emerged and will be discussed.

Lymphoid apoptosis and myeloid hyperplasia in CCAAT displacement protein mutant mice

CCAAT displacement protein (cux/CDP) is an atypical homeodomain protein that represses expression of several developmentally regulated lymphoid and myeloid genes in vitro, including gp91-phox, immunoglobulin heavy chain, the T-cell receptor beta and gamma chains, and CD8. To determine how this activity affects cell development in vivo, a hypomorphic allele of cux/CDP was created by gene targeting. Homozygous mutant mice (cux/CDP(Delta HD/Delta HD)) demonstrated a partial neonatal lethality phenotype. Surviving animals suffered from a wasting disease, which usually resulted in death between 2 and 3 weeks of age. Analysis of T lymphopoiesis demonstrated that cux/CDP(Delta HD/Delta HD) mice had dramatically reduced thymic cellularity due to enhanced apoptosis, with a preferential loss of CD4(+)CD8(+) thymocytes. Ectopic CD25 expression was also observed in maturing thymocytes. B lymphopoiesis was also perturbed, with a 2- to 3-fold reduction in total bone marrow B-lineage cells and a preferential loss of cells in transition from pro-B/pre-BI to pre-BII stages due to enhanced apoptosis. These lymphoid abnormalities were independent of effects related to antigen receptor rearrangement. In contrast to the lymphoid demise, cux/CDP(Delta HD/Delta HD) mice demonstrated myeloid hyperplasia. Bone marrow reconstitution experiments identified that many of the hematopoietic defects were linked to microenvironmental effects, suggesting that underexpression of survival factors or overexpression of death-inducing factors accounted for the phenotypes observed. Tumor necrosis factor (TNF) levels were elevated in several tissues, especially thymus, suggesting that TNF may be a target gene for cux/CDP-mediated repression. These data suggest that cux/CDP regulates normal hematopoiesis, in part, by modulating the levels of survival and/or apoptosis factors expressed by the microenvironment.

Comparison of body weight and height of Israeli schoolchildren with the Tanner and Centers for Disease Control and Prevention growth charts

OBJECTIVE

To examine the suitability of the growth charts that are currently used in Israel and consider their replacement with a recent standard. In a sample of schoolchildren, the current Tanner and Whitehouse standards were compared with the new growth charts from the Centers for Disease Control and Prevention (CDC).

METHOD

A total of 746 Israeli healthy children (368 boys and 378 girls) aged 6 to 14 years were sampled from 2 super-regional schools (from the Jewish population). Height was measured using the Leicester height measure, and weight was measured using scales calibrated by the researchers.

RESULTS

In height, 75% of the boys and 81% of the girls fell in the 10th to 90th percentile range of the Tanner standards. In weight, 71% of the boys and 81% of the girls were in the 10th to 90th percentile range. Israeli boys were taller (chi2(1) = 30.53) and heavier (chi2(1) = 29.39), and girls were taller (chi2(1) = 13.81) than predicted by the Tanner standards. The CDC 10th to 90th percentile range included 81% of the boys and 83% of the girls for height and 78% of the boys and 81% of the girls for weight. The girls in our sample were slightly shorter (chi2(1) = 11.87) and lighter (chi2(1) = 9.52) than predicted from the CDC charts. Nevertheless, neither boys' nor girls' body mass index measures (kg/h2) differed from the CDC charts.

CONCLUSIONS

Our data suggest that the CDC growth charts are adequate for assessing Israeli children and slightly better than the current standard. Thus, in the absence of local standards, we recommend the use of the revised CDC growth charts, which include the additional body mass index measure.

A comparison of upper vs. lower and right vs. left visual fields using lexical decision

A series of experiments using the lexical decision task was conducted in order to investigate the functional differences between the upper and lower visual fields (UVF, LoVF) in word recognition. Word-nonword discrimination was swifter and more accurate for word stimuli presented in the UVF. Changing the eccentricity did not affect the UVF advantage over the LoVF. UVF superiority over LoVF was found to be equivalent for both right and left visual hemifield (RVF, LVF). In general, presenting related word primes enhanced all visual field differences in a similar manner (UVF over LoVF and RVF over LVF). However, primes consisting of semantically constraining sentences enhanced the RVF advantage over the LVF, but did not affect the UVF and LoVF differentially. The argument is made that UVF superiority cannot be due to perceptual or attentional differences alone, but must also reflect top-down information flow.

Hydrophone spatial averaging corrections from 1 to 40 MHz

The purpose of this study was to develop and experimentally verify a practical spatial averaging model for frequencies up to 40 MHz. The model is applicable to focused sources of circular geometry, accounts for the effects of hydrophone probe finite aperture, and allows calibration by substitution to be performed when the active elements of reference and tested hydrophone probes differ significantly. Several broadband sources with focal numbers between 3 and 20 were used to produce ultrasound fields with frequencies up to 40 MHz. The effective diameters of the ultrasonic hydrophone probes calibrated in the focal plane of the sources ranged from 150 to 500 microm. Prior to application of the spatial averaging corrections, the hydrophones with diameters smaller than that of the reference hydrophone exhibited experimentally determined absolute sensitivities higher than the true ones. This discrepancy increased with decreasing focal numbers and increasing frequency. It was determined that the error was governed by the cross-section of the beam in the focal plane and the ratio of the effective diameters of the reference and tested hydrophone probes. In addition, the error was found to be reliant on the frequency-dependent effective hydrophone radius. After applying the spatial averaging correction, the overall uncertainty in the hydrophone calibration was on the order of +/-1 dB. The model developed is being extended to be applicable to frequencies beyond 40 MHz, which are becoming increasingly important in diagnostic ultrasound imaging applications.

Examining alcohol outcome expectancies in laboratory and naturalistic bar settings: a within-subject experimental analysis

Using a within-subject design, this study investigated the situational-specificity hypothesis, namely that alcohol outcome expectancies (AOEs), subjective evaluations of AOEs, and the speed with which AOEs are accessed from memory vary as a function of environmental setting. Thirty-nine undergraduates (20 women), of legal drinking age, responded to the Comprehensive Effects of Alcohol questionnaire (K. Fromme, E. Stroot, & D. Kaplan, 1993) that was presented on a laptop computer in 2 counterbalanced contexts: a laboratory setting and an on-campus bar. Response latencies served as dependent measures for memory accessibility. Consistent with previous research (A.-M. Wall, S. A. McKee, & R. E. Hinson, 2000), evidence in support of the situational-specificity hypothesis was found. Specifically, environmental context influenced undergraduates' expectations concerning alcohol's effects and subjective evaluations of AOEs, as well as the speed with which specific AOEs were accessed from memory. Overall, these findings suggest the need for greater attention to situational variation in AOEs.