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B J Moon

Publications and source records attributed to B J Moon.

13 recordsLinked to original sources
PubMed2001

Specific inhibition of transforming growth factor-beta2 expression in human osteoblast cells by antisense phosphorothioate oligonucleotides.

To elucidate the role of endogenous transforming growth factor (TGF)-beta2 on human osteoblast cell, antisense phosphorothioate oligonucleotides (S-ODNs) complementary to regions in mRNA of TGF-beta2 were synthesized and examined their effects on TGF-beta2 production and cell proliferation in a human osteoblast cell line ROS 17/2. Antisense S-ODNs were designated for three different target regions in the mRNA of TGF-beta2. Among several antisense S-ODN analyzed, an oligonucleotide (AS-11) complementary to the translation initiation site of mRNA of TGF-beta2 demonstrated a selective and strong inhibitory effect on TGF-beta2 production in osteoblast cells. Other antisense S-ODNs which were designated for other regions in mRNA of TGF-beta2 and one- or three-base mismatched analogs of AS-11 showed little or much less antisense activities than AS-11. Therefore, the most effective target site in mRNA of TGF-beta2 is at the initiation codon region. The antisense effects of AS-11 were observed without reduction of levels of mRNA of TGF-beta2. Furthermore, the inhibition of TGF-beta2 expression by antisense S-ODN appeared to enhance cell proliferation, demonstrating the growth inhibitory effect of autocrine TGF-beta2 in osteoblast cells.

Blotting, Northern↗
PubMed2000

Human pyridoxal kinase: overexpression and properties of the recombinant enzyme.

Pyridoxal kinase catalyses the phosphorylation of the vitamin B6. A human brain pyridoxal kinase cDNA was isolated, and the recombinant enzyme was overexpressed in E. coli as a fusion protein with maltose binding protein (MBP). Pure pyridoxal kinase exhibits a molecular mass of about 40 kDa when examined by SDS-PAGE and FPLC gel filtration. The recombinant enzyme is a monomer endowed with catalytic activity, indicating that the native quaternary structure of pyridoxal kinase is not a prerequisite for catalytic function. Zn2+ is the most effective divalent cation in the phosphorylation of pyridoxal, and the human enzyme has maximum catalytic activity in the narrow pH range of 5.5-6.0. The Km values for two substrates pyridoxal and ATP are 97 microM and 12 microM, respectively. In addition, the unfolding processes of the recombinant enzyme were monitored by circular dichroism. The values of the free energy change of unfolding (AGo = 1.2 kcal x mol(-1) x K(-1)) and the midpoint transition (1 M) suggested that the enzyme is more stable than ovine pyridoxal kinase against denaturation by guanidine hydrochloride. Intrinsic fluorescence spectra of the human enzyme from red-edge excitation and fluorescence quenching experiments showed that the tryptophanyl residues are not completely exposed and more accessible to neutral acrylamide than to the negatively charged iodide. The first complete set of catalytic and structural properties of human pyridoxal kinase provide valuable information for further biochemical studies on this enzyme.

Cations↗
PubMed1996

An isoleucine to leucine mutation that switches the cofactor requirement of the EcoRV restriction endonuclease from magnesium to manganese.

The EcoRV restriction endonuclease cleaves DNA at its recognition sequence more readily with Mg2+ as the cofactor than with Mn2+ but, at noncognate sequences that differ from the EcoRV site by one base pair, Mn2+ gives higher rates than Mg2+. A mutant of EcoRV, in which an isoleucine near the active site was replaced by leucine, showed the opposite behavior. It had low activity with Mg2+, but, in the presence of Mn2+ ions, it cleaved the recognition site faster than wild-type EcoRV with either Mn2+ or Mg2+. The mutant was also more specific for the recognition sequence than the native enzyme: the noncognate DNA cleavages by wild-type EcoRV and Mn2+ were not detected with the mutant. Further mutagenesis showed that the protein required the same acidic residues at its active site as wild-type EcoRV. The Ile-->Leu mutation seems to perturb the configuration of the metal-binding ligands at the active site so that the protein has virtually no affinity for Mg2+ yet it can still bind Mn2+ ions, though the latter only occurs when the protein is at the recognition site. This contrasts to wild-type EcoRV, where Mn2+ ions bind readily to complexes with either cognate and noncognate DNA and only Mg2+ shows the discrimination between the complexes. The structural perturbation is a specific consequence of leucine in place of isoleucine, since mutants with valine or alanine were similar to wild-type EcoRV.

Base Sequence↗
PubMed1984

Inhibition of aminopeptidases by amastatin and bestatin derivatives. Effect of inhibitor structure on slow-binding processes.

Amastatin [(2S,3R)-3-amino-2-hydroxy-5-methylhexanoyl-L-valyl-L-valyl-L- aspartic acid] and bestatin [(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoyl-L-leucine] are slow-binding, competitive inhibitors of aminopeptidase M (AP-M) with net inhibition constants (Ki) of 1.9 X 10(-8) and 4.1 X 10(-6) M, respectively. The effect of inhibitor structure on net Ki and on slow-binding inhibition was evaluated for analogues of both inhibitors on AP-M and leucine aminopeptidase (LAP). The (2S)-hydroxyl group contributes to the stabilization of a collision complex [EI], which is formed rapidly. In contrast, increasing the peptide chain length of the inhibitor produces more potent inhibitors as a consequence of a slower binding process. A statine analogue of amastatin [(3S,4S)-Sta-Val-Val-Asp] stimulated rather than inhibited LAP. AP-M binds tri- and tetrapeptide inhibitors more strongly than dipeptide inhibitors, whereas LAP binds dipeptide inhibitors more strongly. The difference in binding can be used to distinguish cytosolic from membrane-bound aminopeptidases.

Aminopeptidases↗
PubMedDate not supplied

Prescriptive authority and nurse-midwives.

The purpose of this paper is to provide an overview of issues relevant to the question of prescriptive authority for nurse-midwives. Nurse-midwives can be held liable for prescriptive competency as evidenced by the American College of Nurse-Midwives' statements, physician delegation of prescribing privileges, and recent court rulings. Despite this liability, nurse-midwives are denied legally sanctioned authority if they are not granted prescriptive privilege by specific legislation. This discussion concludes with a position in favor of direct prescriptive authority, regulated by boards of nursing, for all nurse-midwives in order to remove unnecessary restrictions to the practice of an important member of the health-care team.

Drug Prescriptions↗
PubMedDate not supplied

Prolonged neuromuscular blockade with pancuronium in the presence of acute renal failure: a case report.

Prolongation of neuromuscular block following pancuronium administration to anephric patients has been reported. A patient is described whose postoperative course after resection of gangrenous bowel was complicated by acute renal failure and prolonged neuromuscular blockade. A large intraoperative dose of pancuronium was administered without monitoring neuromuscular transmission with a peripheral nerve stimulator. The course was further complicated by administration of gentamicin, an antibiotic known to potentiate neuromuscular blocking drugs. Complete return of neuromuscular transmission occurred 60 hours after administration of last dose of pancuronium and subsequent to peritoneal dialysis. After rapid distribution from plasma, pancuronium, like curare, is eliminated by the renal pathway. The absence of renal excretion considerably increases the duration of action of curare when given in high doses. It has been suggested that doses of pancuronium greater than 3.6 mg/sq m or multiple doses would result in prolonged neuromuscular block in patients without renal function. The case reported illustrates the importance of monitoring neuromuscular transmission during administration of pancuronium in the presence of renal insufficiency to avoid this complication.

Acute Kidney Injury↗