Inhibition of lysyl hydroxylase by catechol analogs.

Catechol analogs inhibit the activity of lysyl hydroxylase (peptidyllysine, 2-oxyglutarate: oxygen 5-oxidoreductase, EC 1.14.11.4), a microsomal enzyme which catalyzes the transformation of certain lysyl residues in collagen to hydroxylysine. Chick embryo lysyl hydroxylase activity was measured by specific tritium release as tritiated water from an L-[4,5-3H]lysine-labelled unhydroxylated collagen substrate prepared from chick calvaria. Catechol analogs did not bind irreversibly to either enzyme or substrate, as full activity was restored with dialysis. Addition of excess cofactor, Fe2+, ascorbic acid, or alpha-ketoglutarate, did not affect inhibition. Kinetic analysis revealed that with respect to collagen substrate, catechol demonstrated a noncompetitive type of inhibition with a Ki of 15 muM.

Clinical patterns of metastasis.

In human solid cancer, lymph node status is the most important indicator for clinical outcome. Recent developments in the sentinel lymph node concept and technology have resulted in a more precise way of examining micrometastasis in the sentinel lymph node and the role of lymphovascular system in the facilitation of cancer metastasis. Different patterns of metastasis are described with respect to different types of solid cancer. Expect perhaps for papillary carcinoma and sarcoma, the overwhelming evidence is that solid cancer progresses in an orderly progression from the primary site to the regional lymph node or the sentinel lymph node in the majority of cases with subsequent dissemination to the systemic sites. The basic mechanisms of cancer metastasis through the lymphovascular system form the basis of rational therapy against cancer. Beyond the clinical patterns of metastasis, it is imperative to understand the biology of metastasis and to characterize patterns of metastasis perhaps due to heterogeneous clones based on their molecular signatures.

Direct measurements of Ab and Ac using vertex and kaon charge tags at the SLAC detector.

Exploiting the manipulation of the SLAC Linear Collider electron-beam polarization, we present precise direct measurements of the parity-violation parameters A(c) and A(b) in the Z-boson-c-quark and Z-boson-b-quark coupling. Quark-antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLAC Large Detector charge coupled device vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-1998 sample of 400 000 Z decays, produced with an average beam polarization of 73.4%, we find A(c)=0.673+/-0.029(stat)+/-0.023(syst) and A(b)=0.919+/-0.018(stat)+/-0.017(syst).

Study projects mursing staff needs, budget.

Nursing service uses method that accurately determines staffing requirements for each unit, as well as the required budget for such staffing.

The role of superoxide radical in the autoxidation of cytochrome c.

The net rate of autoxidation of ferrocytochrome c was decreased by ferricytochrome c. Superoxide dismutase accelerated this autoxidation to a limit and overcame the inhibitory effect of ferricytochrome c. This was the case whether the autoxidationwas observed in the presence or in the absence of denaturants, such as alcohols orurea, and whether the superoxide dismutase used was the Cu-2+-Zn-2+ enzyme from bovine erythrocytes or the Mn-3+-enzyme from Escherichia coli. It can be deduced that the autoxidation of ferrocytochrome c, under a variety of conditions, geenerates O2 minus which can then dismute to H202 + O2 or can reduce ferricytochrome c back to ferrocytochrome c. Superoxide dismutase, by accelerating the dismutation of O2 minus, prevents the back reaction and thus exposes the true rate of reaction of ferrocytochrome c with molecular oxygen.

Identification of vicinal thiols of phosphoenolpyruvate carboxykinase (GTP).

Phosphoenolpyruvate carboxykinase (PEPCK) from the cytosol of rat liver has 13 cysteines, at least one of which (Cys288) is known to be very reactive and critical for catalytic activity (Lewis, C. T., Seyer, J. M., and Carlson, G. M. (1989) J. Biol. Chem. 264, 27-33). Previous results provided evidence for the existence of at least 1 pair of vicinal cysteines within or near the active site of PEPCK (Lewis, C. T., Haley, B. E., and Carlson, G. M. (1989) Biochemistry 28, 9248-9255). An intramolecular cystine disulfide is induced to form upon treatment of PEPCK with equimolar 5,5'-dithiobis(2-nitrobenzoate) (Nbs2) or upon irradiation of the enzyme in the presence of the photoaffinity probe 8-azidoGTP. In each case, modification is accompanied by a substantial loss in catalytic activity, and substrates protect against inactivation and modification. We now report the identification of these modified thiols by differential alkylation of cysteines and half-cystines with radioactive iodoacetate, followed by isolation and sequencing of the modified tryptic peptides. The results indicate that the disulfide formed by equimolar Nbs2 lies within a 15-residue region of the PEPCK sequence that includes Cys399, Cys407, and Cys413. In addition, Cys407 and/or Cys413 also appear to participate in formation of the disulfide induced by 8-azidoGTP. These thiols lie very near a consensus sequence that has been suggested to represent the binding site for the guanine ring of GTP.

High-precision measurement of the left-right Z Boson cross-section asymmetry.

We present a measurement of the left-right cross-section asymmetry ( A(LR)) for Z boson production by e(+)e(-) collisions. The measurement includes the final data taken with the SLD detector at the SLAC Linear Collider during the period 1996-1998. Using a sample of 383 487 Z decays collected during the 1996-1998 runs we measure the pole value of the asymmetry, A(0)(LR), to be 0.150 56+/-0.002 39 which is equivalent to an effective weak mixing angle of sin (2)straight theta(eff)(W) = 0.231 07+/-0.000 30. Our result for the complete 1992-1998 data set comprising approximately 537 000 Z decays is sin (2)straight theta(eff)(W) = 0.230 97+/-0.000 27.

Improved direct measurement of A(b) and A(c) at the Z(0) pole using a lepton tag.

The parity violation parameters A(b) and A(c) of the Zb(b) and Zc(c) couplings have been measured directly, using the polar angle dependence of the polarized cross sections at the Z(0) pole. Bottom and charmed hadrons were tagged via their semileptonic decays. Both the electron and muon analyses take advantage of new multivariate techniques to increase the analyzing power. Based on the 1993-1998 SLD sample of 550,000 Z(0) decays produced with highly polarized electron beams, we measure A(b) = 0.919+/-0.030(stat)+/-0.024(syst), and A(c) = 0.583+/-0.055(stat)+/-0.055(syst).

First symmetry tests in polarized Z0 decays to bbg.

We have made the first direct symmetry tests in the decays of polarized Z0 bosons into fully identified bbg states, collected in the SLD experiment at SLAC. We searched for evidence of parity violation at the bbg vertex by studying the asymmetries in the b-quark polar- and azimuthal-angle distributions, and for evidence of T-odd, CP-even or CP-odd, final-state interactions by measuring angular correlations between the three-jet plane and the Z0 polarization. We found results consistent with standard model expectations and set 95% C. limits on anomalous contributions.