Immunological properties of monoclonal antibodies to human and rat prolyl 4-hydroxylase

Monoclonal antibodies to human (8 clones) and rat (12 clones) prolyl 4-hydroxylase [EC 1.14.11.2] were prepared and characterized as regards subclass, subunit specificity, inhibition and crossreactivity. Among the antibodies to the human enzyme, four clones showed the IgG1 subclass, two IgA, one IgG2b, and one IgM. Four clones reacted with the alpha subunit of the enzyme, while the others reacted with the beta subunit. The enzymatic activity was inhibited by four clones. Five clones crossreacted with the rat enzyme. One clone inhibited the rat enzyme. Among the antibodies to the rat enzyme, seven clones showed the IgG1 subclass, four IgG2a and one IgG2b. Seven clones reacted with the alpha subunit, and four with the beta subunit. One reacted with neither subunit. The enzymatic activity was inhibited by seven clones. Seven clones crossreacted with the human enzyme. Three clones inhibited the human enzyme.     

Clinical Isolate of Pseudomonas aeruginosa that Degrades Salicylate by the ortho Pathway

A clinical isolate of Pseudomonas aeruginosa was found capable of utilizing salicylate by the salicylate hydroxylase and β-ketoadipate pathway.     

Changes in blood osmolarity,electrolytes, and metabolites among adult rats treated with a neurotoxic dose of MSG1

Adult rats were given large doses of MSG (4 g/kg) or isosmolar amounts of sodium chloride or L-alanine intraperitoneally or by forced intubation. Blood or plasma samples from these rats where assayed for osmolarity, hematocrit, pH, and concentrations of protein, sodium, potassium, chloride, calcium, magnesium, and urea nitrogen. Intraperitoneal MSG produced characteristic hypothalamic lesions; MSG by gavage failed to do so. Intraperitoneal MSG also caused major increases in plasma osmolarity, hemoconcentration, hypovolemia, alkalosis, hypernatremia, and uremia; plasma levels of chloride and potassium fell significantly. Administration of MSG by gavage caused much smaller changes in plasma osmolarity and sodium, and no significant changes in hematocrit, plasma protein or plasma urea nitrogen. Administration of sodium chloride or L-alanine (agents not known to produce the characteristics MSG brain lesions) caused some, but not all, of the metabolic changes seen after MSG. These observations suppot the hypothesis that the ability of large, concentrated doses of MSG to produce brain lesions in susceptible species involves a two-step process, i.e., initial damage to the blood-brain barrier for glutamate, followed by entry of the circulating amino acid into the extracellular space of the brain.     

Preservation and biodegradation of the morphogenetic property of bone matrix

The bone morphogenetic property of bone matrix is degraded at 25 ° to 37 °C within 24 hours after a bone is removed from the body. The degradation occurs in the intact undemineralized bone from the action of endogenous enzymes, presumably neutral proteinases at pH optima of 7 · 0 to 7 · 4. Degradation is: more rapid at physiologic than at acid pH; heat inactivated in the range between 40 ° and 60 °C; slow at 2 °C over a period of 7 days in EDTA at pH 7 · 4. Degradation is inhibited by iodoacetic acid at concentrations as low as 3 · 0 mmoles per liter either in phosphate buffer or EDTA. Degradative activity of endogenous enzymes, as measured by the yield of bone from implants of matrix, is comparable to those obtained from matrix treated with trypsin at 15 °C, pH 7 · 6 over a period of 12 hours. These enzymes include a neutral proteinase (BMP-ase) which degrades bone morphogenetic protein (BMP) without mobilizing bone collagen hydroxy-proline as rapidly and as selectively as a specific functional entity. Observations on carboxypeptidase A and thermolysin cleavage of phenylalanine groups and data on acetylation of tyrosyl groups reducing bone yield suggest aromatic amino acids may be necessary for the biologically active conformation of BMP.     

Musk xylene is a novel specific inducer of cytochrome P-450IA2.

The effect of musk xylene on contents of both cytochrome P-450IA1 and cytochrome P-450IA2 in rat liver was investigated using Western blotting analysis. Rats were treated i.p. for five consecutive days with either 50, 100 or 200 mg musk xylene/kg body weight. Musk xylene increased both total cytochrome P-450 and cytochrome b5 contents in rat liver microsomes. Musk xylene induced cytochrome P-450IA2 (384 pmol/mg protein) strongly and preferentially and the ratio of cytochrome P450IA2/P-450IA1 was about 12 at the lowest dose tested. Musk xylene also induced the cytochrome P-450IA1 dose-dependently, but these extents were very small (32-174 pmol/mg protein). These results suggest that musk xylene may be a more specific inducer for cytochrome P-450IA2 than any other inducers reported.     

Linear correlation between acetoacetate/beta-hydroxybutyrate in arterial blood and oxidized flavoprotein/reduced pyridine nucleotide in freeze-trapped human liver tissue.

A comparison of two methods of measuring liver mitochondrial redox state demonstrated that a linear correlation exists between acetoacetate/beta-hydroxybutyrate ratio in arterial blood (arterial ketone body ratio; AKBR) and oxidized flavoprotein/reduced pyridine nucleotide in human liver tissue (FP/PN) as measured by tissue fluorescence spectroscopy, such that [FP/PN] = 0.64 + 0.49 x [AKBR] (r = 0.84, P less than 0.001). This result supports the validity of AKBR as a method of measuring the hepatic mitochondrial redox state of pyridine nucleotide using arterial blood.