Designed beta-sheet peptides that inhibit proliferation and induce apoptosis in endothelial cells.

Novel beta-sheet-forming peptide 33 mers, beta pep peptides, have been designed by using a combination approach employing basic folding principles and incorporating short sequences or proposed key residues from the beta-sheet domains of interleukin-8 (IL-8), platelet factor-4 (PF4) and bactericidal/permeability increasing protein (B/PI). Since PF4 and B/PI are anti-angiogenic and IL-8 is angiogenic, the library of 30 beta pep peptides was assayed for the ability to affect the growth of endothelial cells. Results indicate that five beta pep peptides (beta pep-2, 7, 8, 21 and 25) demonstrate greater than 50% anti-proliferative activity at 30 micrograms/ml, and one of those (beta pep-25) is similarly active at 10 micrograms/ml.

Improved measurement of (15)N-[(1)H] NOEs in the presence of H(N)-water proton chemical exchange.

A simple method is presented to accurately determine (15)N-[(1)H] NOEs in biomolecules in the presence of H(N)-water proton chemical exchange. Three measurements are required: one with nonselective proton saturation and two with different water saturation conditions to determine the equilibrium value of the (15)N signal. This approach is exemplified with data on two peptides, one helix-forming 17-mer and one compactly folded 56-mer.

Folding of beta pep-4 beta-sheet sandwich dimers and tetramers is influenced by aliphatic hydrophobic residues at the intersubunit interface.

For the designed peptide 33mer, beta pep-4, formation of beta-sheet structure [Ilyina, Roongta and Mayo (1997) Biochemistry 36, 5245--5250] is thermodynamically linked to self-association. Dimers and tetramers are stabilized by interactions between hydrophobic residues lying on the hydrophobic faces of the amphipathic monomer subunits. The present study investigates the effects on folding and self-association of the substitution of two key hydrophobic residues (Ile(20) and Val(22)) at the beta-sheet sandwich interface of beta pep-4.

Myocardial oxygenation and high-energy phosphate levels during graded coronary hypoperfusion.

This study was performed to determine the myocyte PO(2) required to sustain normal high-energy phosphate (HEP) levels in the in vivo heart. In 10 normal dogs, myocyte PO(2) values were calculated from the myocardial deoxymyoglobin resonance (Mb-delta) intensity determined with (1)H-NMR spectroscopy during sequential flow reductions produced by a hydraulic occluder that decreased coronary perfusion pressure to approximately 60, 50, and 40 mmHg and, finally, during total occlusion. Myocardial blood flow was measured with microspheres, and HEP levels were determined with (31)P magnetic resonance spectroscopy.

Specific binding of ethanol to cholesterol in organic solvents.

Although ethanol has been reported to affect cholesterol homeostasis in biological membranes, the molecular mechanism of action is unknown. Here, nuclear magnetic resonance (NMR) spectroscopic techniques have been used to investigate possible direct interactions between ethanol and cholesterol in various low dielectric solvents (acetone, methanol, isopropanol, DMF, DMSO, chloroform, and CCl(4)). Measurement of (13)C chemical shifts, spin-lattice and multiplet relaxation times, as well as self-diffusion coefficients, indicates that ethanol interacts weakly, yet specifically, with the HC-OH moiety and the two flanking methylenes in the cyclohexanol ring of cholesterol.

WHIM syndrome, an autosomal dominant disorder: clinical, hematological, and molecular studies.

The acronym WHIM refers to Warts, Hypogammaglobulinemia, Infections, and Myelokathexis. The latter refers to the retention of white cells in the marrow, which becomes hypercellular. We have found approximately 20 examples of WHIM syndrome in the literature under various designations; the first examples are Zuelzer [1964] and Krill et al.

Pharmacologic characteristics of indinavir, didanosine, and stavudine in human immunodeficiency virus-infected children receiving combination therapy.

The use of human immunodeficiency virus (HIV) protease inhibitors in children has lagged behind that in adults because of the lack of suitable pediatric formulations and information on safe and effective dosing regimens. This study was designed to obtain pharmacokinetic information on indinavir, administered to HIV-infected children also receiving therapy with two nucleoside agents, and to explore relationships between pharmacokinetic parameters and anti-HIV effect. Indinavir was initiated at a dose of 500 mg/m(2) every 8 h.

Transmural metabolic heterogeneity at high cardiac work states.

This study compared the transmural distribution of high-energy phosphate (HEP) depletion during oxidative stress induced by pacing- and dobutamine-induced tachycardia in myocardium perfused by a flow-limiting coronary stenosis. Myocardial blood flow (MBF) was measured with radioactive microspheres. Creatine phosphate (CrP), ATP, and P(i) were measured with transmurally localized (31)P NMR spectroscopy.

Oxygen delivery does not limit cardiac performance during high work states.

This study tested the hypothesis that the loss of myocardial high-energy phosphates (HEP), which occurs during high cardiac work states [J. Zhang, D. J.

Facial fracture classification according to skeletal support mechanisms.

Objective: To construct, propose, and evaluate the usefulness of a new clinical facial fracture classification scheme to accurately denote, communicate, and compare facial fractures.

Design: A retrospective, consecutive sample study with application of the proposed classification scheme to denote maxillary and zygomatic fractures with computed tomography.

Setting: Metropolitan tertiary care trauma center.

Inhibition of human class 3 aldehyde dehydrogenase, and sensitization of tumor cells that express significant amounts of this enzyme to oxazaphosphorines, by chlorpropamide analogues.

In some cases, acquired as well as constitutive tumor cell resistance to a group of otherwise clinically useful antineoplastic agents collectively referred to as oxazaphosphorines, e.g. cyclophosphamide and mafosfamide, can be accounted for by relatively elevated cellular levels of an enzyme, viz.

The infectious complications of chronic lymphocytic leukemia.

Infectious complications continue to have a major impact on the clinical course of patients with chronic lymphocytic leukemia despite advances in therapeutic approaches to this disease and supportive care. Although the pathogenesis of infection in these patients is multifactorial, systemic hypogammaglobulinemia is the major immune defect accounting for the increased risk of infection. Despite common knowledge of systemic immune defects in this population, information regarding mucosal immune function is minimal.

Myocardial bioenergetics during acute hibernation.

During moderate reductions of blood flow, the myocardium downregulates contractile function and ATP utilization to result in reduced but stable ATP levels, recovery or stability of (reduced) creatine phosphate (CP), and preservation of myocyte viability. The intent of this study was to determine the influence of the level of ischemic blood flow and the major determinants of myocardial O2 consumption (MVO2) (heart rate and systolic blood pressure) on recovery of CP during prolonged moderate myocardial hypoperfusion. 31P-nuclear magnetic resonance spectroscopy was used to measure CP, ATP, and Pi in the subepicardium (Epi) and subendocardium (Endo) of 13 open-chest dogs.

Pharmacokinetics and safety of concentration-controlled oral zidovudine therapy.

Study Objective: To evaluate the pharmacokinetics, safety, and feasibility of concentration-controlled oral zidovudine therapy.

Design: Randomized, crossover, open-label study.

Setting: University-affiliated general clinical research center.

NMR structure of a de novo designed, peptide 33mer with two distinct, compact beta-sheet folds.

A de novo designed 33-residue polypeptide folds as a compact beta-sheet sandwich tetramer in aqueous solution. NMR structural analysis shows that although monomer subunits have the same three-stranded antiparallel beta-sheet fold, two equally populated conformational states are identified. Conformational heterogeneity arises from formation of two distinct dimer folds.

Zebrafish translation elongation factor EF1 alpha mRNA: sequence and secondary structures.

We have determined the complete sequence of the translation elongation factor EF1 subunit alpha (EF1 alpha) mRNA of zebrafish, and the 3'-untranslated sequence of EF1 alpha mRNA of halibut. The 5'-untranslated leader sequence of the EF1 alpha mRNA starts with a polypyrimidine tract. This feature is shared with the mRNAs for ribosomal proteins, where it affects the utilization of mRNA by ribosomes.

Role of hydroxyl radicals in radiation-induced activation of lyn tyrosine kinase in human B-cell precursors.

Here we show that exposure of human B-cell precursors to gamma-rays stimulates the enzymatic activity of the Src protooncogene family protein tyrosine kinase LYN. LYN activation in irradiated cells is not triggered by DNA damage or a nuclear signal since gamma-rays effectively stimulated LYN kinase in enucleated B-cell precursors as well. LYN activation in irradiated cells was abrogated by presence of the OH* radical scavenger dimethylsulfoxide and exposure of intact or enucleated B-cell precursors to chemically generated OH* radicals instead of gamma-rays also triggered LYN kinase activation and enhanced tyrosine phosphorylation of multiple electrophoretically distinct protein substrates.

Related donor marrow transplant for chronic myeloid leukemia: patient characteristics predictive of outcome.

Pre-transplant characteristics of 137 consecutive patients (including 103 patients with one or more features suggesting advanced disease) undergoing related donor marrow transplant for chronic myeloid leukemia (CML) were analyzed to determine their association with outcome. Multivariate analysis identified increased recipient age (relative risk (RR) for patients over 30 years of relapse or death 2.37; P = 0.

Physical and functional interactions between Lyn and p34cdc2 kinases in irradiated human B-cell precursors.

Exposure of human B-cell precursors (BCP) to ionizing radiation results in cell cycle arrest at the G2-M checkpoint as a result of inhibitory tyrosine phosphorylation of p34cdc2 . Here, we show that ionizing radiation promotes physical interactions between p34cdc2 and the Src family protein-tyrosine kinase Lyn in the cytoplasm of human BCP leading to tyrosine phosphorylation of p34cdc2. Lyn kinase immunoprecipitated from lysates of irradiated BCP as well as a full-length glutathione S-transferase (GST)-Lyn fusion protein-phosphorylated recombinant human p34cdc2 on tyrosine 15.

Role of tyrosine phosphorylation in radiation-induced cell cycle-arrest of leukemic B-cell precursors at the G2-M transition checkpoint.

Here we provide experimental evidence that ionizing radiation induces inhibitory tyrosine phosphorylation of the p34cdc2 kinase in human leukemic B-cell precursors. Herbimycin A markedly reduced tyrosine phosphorylation of p34cdc2 in irradiated leukemic B-cell precursors, thereby preventing radiation-induced cell cycle arrest at the G2-M transition checkpoint. Thus, tyrosine phosphorylation is directly responsible for the inactivation of p34cdc2 in irradiated human leukemic B-cell precursors and activation of protein tyrosine kinases is a proximal and mandatory step in radiation-induced G2-arrest arrest at the G2-M checkpoint.

Strategies for control of zidovudine concentrations in serum.

There are several clinical scenarios in which knowledge of zidovudine disposition may be important. This study evaluated the clinical utility of pharmacokinetic parameters for zidovudine derived from sparse serum concentration data obtained in an outpatient setting. Twelve human immunodeficiency virus-infected participants had two serum zidovudine concentrations determinations obtained on two different clinic visits, 2 to 38 days apart.

In vitro and in vivo antileukemic activity of B43-pokeweed antiviral protein against radiation-resistant human B-cell precursor leukemia cells.

B-cell precursor (BCP) leukemia is the most common form of childhood cancer and represents one of the most radiation-resistant forms of human malignancy. In this study, we examined the antileukemic efficacy of the B43 (anti-CD19)-pokeweed antiviral protein (B43-PAP) immunotoxin against radiation-resistant BCP leukemia cells. B43-PAP caused apoptosis of radiation-resistant primary BCP leukemia cells, killed greater than 99% of radiation-resistant primary leukemic progenitor cells from BCP leukemia patients, and conferred extended survival to severe combined immunodeficiency (SCID) mice xenografted with radiation-resistant human BCP leukemia.

Exposure of B-lineage lymphoid cells to low energy electromagnetic fields stimulates Lyn kinase.

Here, we present evidence that exposure of B-lineage lymphoid cells to low energy electromagnetic fields (EMF) stimulates the protein tyrosine kinases Lyn and Syk, results in tyrosine phosphorylation of multiple electrophoretically distinct substrates, and leads to downstream activation of protein kinase C (PKC). EMF exposure enhances protein tyrosine phosphorylation in Syk deficient but not in Lyn-deficient B-lineage lymphoid cells and stimulates Lyn kinase activity in wild-type as well as Syk-deficient B-lineage lymphoid cells. These results indicate that activation of Lyn kinase is sufficient and mandatory for EMF-induced tyrosine phosphorylation in B-lineage lymphoid cells.