A lysyl residue at the NADP binding site of ferredoxin-NADP reductase. Dansyl chloride, at low molar ratio, inactivates ferredoxin-NADP reductase (NADPH:ferredoxin oxidoreductase, EC 1.6.7.1). The complete protection afforded either by NADP or NADPH suggests a direct involvement of the active site. Experiments with [Me-14C] dansyl chloride showed that about 1.5 residues per flavin were dansylated: by differential labelling experiments using NADP, it has been proved that enzyme inactivation is due to dansylation of one residue. The group modified has been identified as the epsilon-amino group of a lysine. The pH-inactivation profile indicates that this essential group has an apparent pKa of 8.7. The dansylated flavoprotein seems to maintain its native conformation; it shows a fluorescent chromophore with a peak at 335 nm. The modified enzyme has lost the capacity to form a complex with NADP, nevertheless it interacts normally with ferredoxin. It is concluded that the loss of catalytic activity which parallels the dansylation of a lysyl residue occurs because this residue is essential for the binding of the pyridine nucleotide substrate. Protection experiments with a series of coenzyme analogs further indicate that this lysyl residue interacts, most likely, with the 2'-phosphate moiety of NADP(H).


Specfic irreversible inhibition of sweet-almond beta-glucosidase by some beta-glycopyranosylepoxyalkanes and beta-d-glucopyranosyl isothiocyanate. beta-D-Glucopyranosyl-(1S and 1R)-epoxyethanes (I and II), 1-(beta-D-glucopyranosyl)-(2R and 2S)-2,3-epoxypropanes (III and IV), beta-D-glucopyranosyl isothiocyanate (V) and beta-D-galactopyranosylepoxyethane (VI) are active-site-directed irreversible inhibitors of sweet-almond beta-glucosidase B (beta-D-Glucoside glucohydrolase, EC 3.2.1.21). Formation of the covalent bond is preceded by the binding of these inhibitors in the active site of the enzyme. This is testitified by the competitive character of inhibition of beta-glucosidase component B by compounds I-VI at the early period and by the protection of the enzyme from inactivation by its competitive inhibitors D-glucose and 1,5-D-gluconolactone. Epoxides I-IV are bound covalently with componet B at a molar ratio 1 : 1 as shown with the aid of 14C-labelled inhibitors. The release of the label from modified enzyme (E-I covalent) by treatment with hydroxylamine suggests the formation of an ester bond between inhibitors I-IV and the carboxyl group of the enzyme active site. The pH dependence curve of the inactivation rate of beta-glucosidase B is of a bell-shaped form for V and of a sigmoid character for I-IV and points to the involvement of the active site groups with pKa 5.6-5.9 and 4.2-4.4.


Denaturation of subtilisin BPN' and its derivatives in aqueous guanidine hydrochloride solutions. The denaturation of subtilisin BPN' (EC 3.4.21.14) in guanidine hydrochloride was studied in order to find possible reasons for the exceptional stability of this enzyme against the action of denaturing agents including guanidine hydrochloride. Chemically modified subtilisins, i.e., phenylmethanesulfonylsubtilisin and thio-subtilisin, were  completely denatured in 2 M guanidine hydrochloride at pH 7 without autolysis but they were stable in 0.5 M guanidine hydrochloride for at least 60 h. On the other hand, once completely denatured, the subtilisins remained inactive and in highly unfolded conformations for 60 h or longer after transfer into 0.5 M guanidine solution at pH 7 or 9. No enzymatic activity was regained when the guanidine concentration was lowered to almost zero. We concluded from these and other results described in this paper that this enzyme was thermodynamically unstable in 2 M guanidine hydrochloride at 20 degrees C and at pH 7. We wish to point out the possibility that the denaturation of this enzyme could indeed be irreversible.


Purification and characterization of the two molecular forms of Aspergillus oryzae acid protease. The isolation and partial characterization of the acid proteases A1 and A2 (EC3.4.23.6) from Aspergillus oryzae grown on solid bran culture are described. The purified preparations were essentially homogeneous by several criteria including sedimentation analysis and polyacrylamide gel electrophoresis. The physiochemical properties of the proteases A1 and A2 were as follows (in the order: A1, A2): molecular weight: 63 000 & 32 000; sedimentation coefficient s20, w: 3.93 and 3.16 S; diffusion constant D20, w, 5.63 - 10(-7) and 8.61 - 10(-7) CM2/S, partial specific volume, v: 0.73 ml/g for both; nitrogen content: 16.30 and 13.42%; E1% 1 cm at 280 nm: 5.9 and 11.1. The two enzymes had the same pH optima in the acid pH range, and both activated bovine pancreatic trypsinogen. The enzymes were essentially of the same amino acid composition and immunologically cross-reacted with each other. The protease A2 contained little or no carbohydrate, whereas the protease A1 was glycoprotein, containing 49% carbohydrate comprising glucose, mannose, and galactose. These results suggest that the protein portion of acid protease A1 is the same as that of acid protease A2.


Steady-state studies of the actin-activated adenosine triphosphatase activity of myosin. Reconstituted actomyosin (ATP phosphohydrolase, EC 3.6.1.3) (0.400 mg F-actin/mg myosin) in 10.0 muM ATP loses 96% of its specific ATPase activity when its reaction concentration is decreased from 42.0 mug/ml down to 0.700 mug/ml. The loss of specific activity at the very low enzyme concentrations is prevented by the addition of more F-actin to 17.6 mug/ml. It is concluded that at low actomyosin concentrations the complex dissociates into free myosin with a very low specific ATPase activity and free F-actin with no ATPase. The dissociation of the essential low molecular weight subunits of myosin from the heavy chains at very low actomyosin concentrations may be a contributing factor. Actomyosin has its maximum specific activity at pH 7.8-8.2. The Km for ATP is 9.4 muM, which is at least 20-fold greater than myosin's Km for ATP. The actin-activated ATPase of myosin follows hyperbolic kinetics with varying F-actin concentrations. The Km values for F-actin are 0.110 muM (4.95 mug/ml) at pH 7.4 and 0.241 muM (10.8 mug/ml) at pH 7.8. The actin-activated maximum turnover numbers for myosin are 9.3 s-1 at pH 7.4 and 11.6 s-1 at pH 7.8. The actomyosin ATPase is inhibited by KCl. This KCl inhibition is not competitive with respect to F-actin, and it is not a simple form of non-competitive inhibition.


Human fat cell adenylate cyclase. Enzyme characterization and guanine nucleotide effects on epinephrine responsiveness in cell membranes. Human adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) has been studied in preparations of fat cell membranes ("ghosts"). As reported earlier, under ordinary assay conditions (1.0 mM ATP, 5 mM Mg2+, 30 degrees C, 10 min incubation) the enzyme was activated 6-fold by epinephrine in the presence of the GTP analog, 5'-guanylyl-imidodiphosphate [GMP-P(NH)P] (Cooper, B. et al. (1975) J. Clin. Invest. 56, 1350-1353). Basal activity was highest during the first 2 min of incubation then slowed and was linear for at least the next 18 min. Epinephrine, added alone, was often without effect. but sometimes maintained the initial high rate of basal activity. GMP-P(NH)P alone produced inhibition ("lag") of basal enzyme early in the incubation periods. Augmentation of epinephrine effect by GMP-P(NH)P, which also proceeded after a brief (2 min) lag period, was noted over a wide range of substrate (ATP) concentrations. GTP inhibited basal levels of the enzyme by about 50%. GTP also allowed expression of an epinephrine effect, but only in the sense that the hormone abolished the inhibition by GTP. Occasionally a slight stimulatory effect on epinephrine action was seen with GTP. At high Mg2+ concentration (greater than 10 mM) or elevated temperatures (greater than 30 degrees C) GMP-P(NH)P alone activated the enzyme. Maximal activity of human fat cell adenylate cyclase was seen at 50 mM Mg2+, 1.0 mM ATP, pH 8.2, and 37 degrees C in the presence of 10(-4) M GMP-P(NH)P; under these conditions addition of epinephrine did not further enhance activity. Human fat cell adenylate cyclase of adults was insensitive to ACTH and glucagon even in the presence of GMP-P(NH)P.


NADP+-specific isocitrate dehydrogenase of Excherichia coli. III. Two-step purification employing affinity chromatography. The NADP+-specific isocitrate dehydrogenase (threo-DS-isocitrate:NADP+ oxidoreductase (decarboxylating), EC 1.1.1.42) of Excherichia coli has been purified to electrophoretic homogeneity by a two-step purification procedure employing affinity chromatography. The overall yield of enzyme was 30% with specific activity 125 mumol/min per ng protein. Electrophoretic homogeneity of the isocitrate dehydrogenase was deterimed in analytical polyacrylamide gels in a Tris/acetate/EDTA buffer system at pH 7.5 and in a citrate/phosphate buffer system at pH 6.0.


L-Rhamnose dehydrogenase of pullularia pullulans. Growth of Pullularia pullulans on L-rhamnose induces formation of L-rhamnofuranose dehydrogenase, whichreversibly converts L-rhamnofuranose to L-rhamnono-gamma-lactone with the concomitant reduction of NAD, but not of NADP. The dehydrogenase was purified 100-fold by MnCl(2) treatment...


Human erythrocyte glutathione reductase. I. Purification and properties. 1. Glutathione reductase (NAD(P)H:oxidized-glutathione oxidoreductase, EC. 1.6.4.2) from human erythrocytes was purified 49 000-fold with an overall yield of 15% and a 280/460 nm absorbance ratio of 6.03. The procedure used was the method of Worthington and Rosemeyer modified by addition of heating and recrystallization. 2. It was concluded from the results of purification, electrofocusing and inhibition studies that glutathione reductase is a single enzyme which used both NADPH and NADH as hydrogen donors. 3. Apoenzyme cross-reacts with the antibody to the holoenzyme but has a slightly reduced affinity to the antibody. Apoenzyme can be removed from the hemolysate by heating and centrifugation without loss of holoenzyme. 4. Indirect immunological assay of the specific activity of the erythrocyte glutathione reductase is possible in the enzyme saturated with FAD.


Spectrophotometric pH titrations and nitration with tetranitromethane of the tyrosyl residues in yeast phosphoglycerate kinase. Spectrophotometric pH titrations of phosphoglycerate kinase (EC 2.7.2.3) reveal seven tyrosyl residues. In the native state one tyrosyl residue has pKapp equal to 9.3, another has pKapp of about 12.9, and five have pKapp values close to 11.0. Titration above pH 10 causes concomitant reduction of the catalytic activity. Reactivation of the enzyme occurs during storage at pH 7.8. In 6 M guanidine - HCl seven tyrosyl residues with pKapp values equal to 10.0 appear. Nitration of three tyrosyl residues occurs easily when tetranitromethane is used in excess. Four tyrosyl residues appear to be masked or buried. The tyrosyl residue having pKapp equal to 9.3 can be selectively nitrated. Simultaneously the enzyme loses 40% of its catalytic activity. No change in the Km value for one or the other of the two substrates, MgATP or 3-phospho-D-glycerate, was observed in the mononitrated enzyme. On the other hand MgATP protects the tyrosyl residue from nitration whereas 3-phospho-D-glycerate at corresponding condition appears harmless. These results suggest the low ionizing tyrosyl residue to be situated close to the binding site of MgATP, possibly in a pocket just behind. Circular dichroism measurements indicated that minor successive changes occur in the secondary structure, mainly the beta-structure, when the enzyme is being nitrated. It is reasonable to think that these structural changes, possible in combination with steric hindrance, are responsible for the decrease in catalytic activity. Dimerization of the enzyme occurs if the single thiol group is not masked before the tetranitromethane treatment.


Purification and properties of extracellular alpha-glucosidase of a thermophile, Bacillus thermoglucosidus KP 1006. An extracecular alpha-glucosidase (alpha-D-glucoside glycohydrolase, EC 3.2.1.20) of a thermophile, Bacillus thermoglucosidius KP 1006, was purified about 350-fold. The purified enzyme had a specific activity of 164 mumol of p-nitrophenyl-alpha-D-glucopyranoside hydrolyzed per min at  60 degrees C and pH 6.8 per mg of protein. The molecular weight was estimated at 55 000. The pH and temperature optima for activity were 5.0--6.0 and 75 degrees C, respectively. Below 40 degrees C, the activity was less than 4.5% of the optimym. The enzyme showed a high specificity for alpha-D-glucopyranoside. The maximal hydrolyzing velocity per substrate diminished in the order: phenyl-alpha-D-glucopyranoside, p-nitrophenyl-alpha-D-glucopyranoside, isomaltose, methyl-alpha-glycopyranoside. The respective Km values were 3.0, 0.23, 3.2 and 27 mM. The activity was trace for turanose, and not detectable for sucrose, trehalose, raffinose, melezitose, maltose, maltotriose, phenyl-alpha-D-maltoside, dextran, dextrin and starch. Tris, p-nitrophenyl-alpha-D-xylopyranoside, glucose and glucono-delta-lactone blocked competitively the enzyme with respect to p-nitrophenyl-alpha-D-glucopyranoside. The Ki values were 0.12, 0.14, 2.2 and 2.4 mM, respectively. The activity was affected by heavy metal ions, but insensitive to EDTA, p-chloromercuribenzoate and iodoacetate. The enzyme was stable up to 60 degrees C, and inactivated rapidly at temperatures beyond 72 degrees C. The pH range for stability was 4.0--11.0 at 31 degrees C, and 6.0--8.5 at 55.5 degrees C. At 25 degrees C, the enzyme failed to be inactivated in 45% ethanol, in 7.2 M urea, and in 0.06% sodium dodecyl sulfate, but the tolerance was extremely reduced at 60 degrees C.


Neutral alpha-mannosidase activity in human serum. Two types of alpha-mannosidase (alpha-D-mannoside mannohydrolase, EC 3.2.1.24) with neutral pH optima exist in serum. The activity with an optimum between pH 6.0 and 6.4 is similar to alpha-mannosidase C, described earlier in tissues. The second activity, with a pH optimum between pH 5.2 and 5.8 is the dominant form in serum. These two forms can be differentiated from each other by gel-filtration, chromatography on DEAE-cellulose or chromatography on Concanavalin-A Sepharose. Using the chromatographic techniques, the serum type neutral activity co-elutes with the acidic forms of the enzyme. However, these two forms can be easily distinguished by effect of pH, heating or inhibition by the substrate methyl-alpha-D-mannopyranoside. The presence of the serum type alpha-mannosidase activity is discussed with respect to mannosidosis, a lysosomal storage disease.


Purification and properties of a new aminopeptidase from Escherichia COLI K12. An aminopeptidase (EC 3.4.11.-) capmable of hydrolyzing L-alanyl-beta-naphthyl-amide and certain other aminoacyl beta-naphthylamides was purified to homogeneity from extracts of Exherichia coli K-12. The enzyme, designated aminopeptidase II, is a monomeric protein of mol. wt. 100 000. It exhibits a broad pH optimum in the range pH 7.0--9.0. Although Zn2+, Fe3+ and Cr3+ are strong inhibitors of enzyme activity, a metal requirement for catalysis could not be firmly established. Neither sulfhydryl reagents nor serine protease inhibitors affected enzyme activity.


Proton transfer to a charged dye bound to the alpha-chymotrypsin active site studied by laser photolysis. Pulsed laser photolysis has been used to study the very rapid relaxation of the complex of alpha-chymotrypsin (EC 3.4.21.1) with the coloured inhibitor Biebrich Scarlet. The light absorption causes the dissociation of the proton in the dye naphthol ring and we are able to follow the recombination process under conditions of different ionic strength and pH. The recombination is markedly influenced by the pH around pH 7. The data suggest the existence of relevant interactions in the active site area between the hydrophobic binding site and the proton relay system of the enzyme.


Chemical investigations on pig kidney aminoacylase. 1. Preparations of purified pig kidney aminoacylase (N-Acylamino-acid amidohydrolase, EC 3.5.1.14) were obtained by Sephadex and DEAE-cellulose chromatography in homogeneous form as judged by polyacrylamide gel electrophoresis and immunoelectrophoresis. 2. The apparent molecular weight of the enzyme, determined by gel filtration, was about 86 000. After treatment with mercaptoethanol, performic acid or sodium dodecyl sulphate a band with an apparent molecular weight of approximately 43 000 was observed in polyacrylamide gels containing sodium dodecyl sulphate. Thus pig kidney aminoacylase seems to be composed of two subunits. 3. The amino acid composition of the enzyme was determined. Aminoacylase contains 772 amino acids, which corresponds to a molecular weight of 85 500. 12 tryptophan and 12 half-cystine residues were found. 4. Each subunit of the enzyme contains two -SH groups of different reactivity and two disulfide bonds one of which is easily cleaved by -SH compounds, the second only by performic acid oxidation. 5. Chemical modification of two -SH groups abolishes the catalytic activity of aminoacylase. Cleavage of two disulfide bonds also inactivates the enzyme. It is suggested that the enzyme has two active sites each containing an essential -SH group and disulfide bond. One active site is assumed to be part of each subunit.


HCO-3-activated adenosine triphosphatase in intestinal mucosa of the eel. An HCO-3-activated and SCN--inhibited ATPase (ATP phosphohydrolase, EC 3.6.1.3) found in homogenates of intestinal mucosa of the eel was solubilized by Triton X-100. Optimal HCO-3-concentration and pH for the enzyme were 25 mM and 8.7, respectively. HCO-3-ATPase activity in both homogenate and solubilized preparations increased after seawater adaptation. This adaptive increase in enzyme activity was also observed in the gills and the kidney. The HCO-3-ATPase seems to be related to transport mechanisms, especially for Cl-, in osmoregulatory surfaces of the eel.


Properties of guanylate cyclase in adult rat liver and several Morris hepatomas. Guanylate cyclase (GTP pyrophyosphate-lyase (cyclizing), EC 4.6.1.2) activity was examined in preparations from normal rat liver and a series of Morris hepatomas. Homogenate gyanylate cyclase activites were 3.2, 1.6 and 1.2 nmol cyclic GMP formed per min/g tissue ihe non-substrate analogs of IMP were weak inhibitors of this enzyme, GMP and four of its analogs had Ki values ranging from 30 to 80 muM. The GMP analogs (8-azaGMP, 7-deaza-8-azaGMP, 2'-dGMP and beta-D-arabinosylGMP) and GMP were competitive inhibitors with respect to GTP.


Role of lysyl-tRNA in the regulation of lysine biosynthesis in Escherichia coli K12. A mutant of lysyl-tRNA synthetase has been isolated in Escherichia coli K12. With this strain the Kmapp for lysine is 25 fold higher than with the parental strain. The percentage of charged tRNAlys in vivo is only 7 per cent (as against 65 per cent with HFR H). Under these conditions no derepression of synthesis is observed for three lysine biosynthetic enzymes (AK III, ASA-dehydrogenase, DAP-decarboxylase) ; a partial derepression is obtained in the case of the dhdp-reductase. Thus lysyl-tRNA does not act as the only corepressor molecule in the lysine regulon.


Mechanistic studies of glutamine synthetase from Escherichia coli. An integrated mechanism for biosynthesis, transferase, ATPase reaction. The mechanism of biosynthetic, transferase, ATPase, and transphosphorylation reactions catalyzed by unadenylylated glutamine synthetase from E. coli was studied. Activation complex(es) involved in the biosynthetic reaction are produced in the presence of either Mg2+ or Mn2+ ; however, with the Mn2+-enzyme inhibition by the product, ADP, is so great that the overall forward biosynthetic reaction cannot be detected with the known assay methods. Binding studies show that substrates (except for NH3 and NH2OH which are not reported here) can bind to the enzyme in a random manner and that binding of the ATP-glutamate, ADP-Pi or ADP-arsenate pairs is strongly synergistic. Inhibition and binding studies show that the same binding site is utilized for glutamate and glutamine in biosynthetic and transferase reactions, respectively, and that a common nucleotide binding site is used for all reactions studied. Studies of the reverse biosynthetic reaction and results of fluorescent titration experiments suggest that both arsenate and orthophosphate bind at a site which overlaps the gamma-phosphate site of nucleoside triphosphate. In the reverse biosynthetic and transferase reactions, ATP serves as a substrate for the Mn2+-enzyme but not for the Mg2+-enzyme. The ATP supported transferase activity of Mn2+-enzyme is probably facilitated by the generation of ADP through ATP hydrolysis. When AMP was the only nucleotide substrate added, it was converted to ATP with concomitant formation of two equivalents of glutamate, under the reverse biosynthetic reaction conditions, and no ADP was detected. The reversibility of 180 transfer between orthophosphate and gamma-acyl group of glutamate was confirmed. ATPase activity of Mg2+ and Mn2+ unadenylylated enzymes is about the same. Both enzymes forms catalyze transphosphorylation reactions between various purine nucleoside triphosphates and nucleoside diphosphates under biosynthetic reaction conditions. The data are consistent with the hypothesis that a single active center is utilized for all reactions studied. Two stepwise mecanisms that could explain the results are discussed.


Effects of activators on chemically modified yeast hexokinase. Enzymic studies performed with chemically modified yeast hexokinase (ATP : D-hexose-6-phosphotransferase) confirm previous results indicating that the sulfhydryl, imidazol and most of the reactive amino groups do not seem to be directly implicated in the enzyme active site. On the other hand the modification of these functional groups of the enzyme does not affect the transition between the acidic inactive form to an active enzyme form after deprotonation. The chemically modified forms of hexokinase and the native enzyme are affected in the same way by activators (citrate, D-malate, 3-phosphoglycerate and Pi) when the activity was measured at pH 6.6. Moreover the loss of enzyme activity observed in the course of the chemical modifications is accompanied by an increase of the activation effect. This increase must be related to some reorganization of the enzyme active site in presence of the effectors, since the same effect was observed when hexokinase was denatured with 3M urea at pH 7.5. However no increase in the activation effect was observed when the denaturation was carried out at pH 6.5 At this pH the loss in activity and the change of optical absorption at 286 nm were much slower than at pH 7.5, which indicates a great difference in the protein structure between these pHs.


Phospholipases A1 and A2 of rat liver plasma membranes; mechanism of action. While V/S plots of phospholipase A1 show a phase transition, kinetic behaviour of phospholipase A2 acting in the same concentration range is hyperbolic. However after phospholipase A2 has been solubilized from the plasma membranes by 1 M NaCl, the V/S curve shows a phase transition. Membrane-bound phospholipase A1 shows a narrow optimum pH at 8.5 -9, while phospholipase A2 activity presents only small variations between pH 7 and 9.5. Towards exogenous phospholipids at the optimum pH 8.5 of phospholipase A1, the specific activity of the latter is 3-fold higher than phospholipase A2 specific activity. On the contrary towards endogenous phospholipids, phospolipase A2 activity is higher than phospholipase A2 activity. Moreover labeled endogenous PE hydrolysis by phospholipase A2 is decreased by addition of non labeled exogenous PE into the incubation medium. All these data suggest that the active site of phospholipase A1 is turned to the outside and acts only on exogenous substrates: for phospholipase A2 it would be inside, and exogenous phospholipids could be hydrolyzed only after penetrating the membrane.


[Kinetics of Ca 2+ or Mg 2+ activated ATPase from lymphocyte plasma membranes]. The kinetic study of the C2+ ATPase activity of lymphocyte plasma memebranes allowed some properties of this enzyme to be evidenced. The Ca2+-activated hydrolysis of ATP is independent of a non-specific alkaline phosphatase. The substrate of the ATPase activity is the chelate Ca2+- ATP. Mg2+ may substitute for Ca2+ both as chelating ion and as activating ion. Several results suggest that we have only one ATPase, activated either by Ca2+-, or by Mg2+ with less efficiency; both chelates hve the same Km; pH values for maximum activity and transition temperatures are identical; the effects of free ions are also the same, activation at low concentration and inhibition at high concentration.


The reaction of the histidine residues of luteinizing hormone with ethoxyformyl anhydride. Bovine and porcine luteinizing hormones (B-LH, P-LH) and their subunits were treated by ethoxyformyl anhydride. The acylation of the histidine residues was followed by examination of the absorbance spectrum. All the histidine residues of the luteinizing hormone molecule can be modified at pH5. However 2 His in B-LH and 1 in P-LH appear to be much less reactive at pH 5 than the others and their acylated imidazols more labile at the same pH. At neutral pH, 2 histidines in B-LH (and 1 in P-LH) become unreactive. In the case of the subunits, 1 histidine becomes unreactive in each subunit at neutral pH. These unreactive histidine residues at neutral pH are probably those which appear to be poorly reactive at pH 5. Comparison of the results obtained with B-LH and P-LH suggests that of the 2 histidine residues present in B-LH and absent in P-LH (beta 60, beta 112), only one exhibits a low reactivity. Acylation of 4 His in B-LH do not cause dissociation into subunits of the molecule but supress 95 per cent of the biological activity.


[Spectroscopic study of the structural changes of scorpion hemocyanin, induced by pH variations and addition of various salts]. Structural modifications of the scorpion haemocyanin induced by pH variations and salt addition are studied by U.V. absorption, fluorescence, circular dichroism and light scattering. Haemocyanin fluorescence is due to both aromatic amino-acids tyrosine and tryptophan. Deoxygenation or denaturation lead to a fourfold enhancement of its intensity. At acidic pH the active site is modified and the protein is dissociated, but at alkaline pH the haemocyanin aggregates. The addition of different salts (sodium citrate, potassium bromide and iodide...) involves protein dissociation, the amplitude of which depends on the anion. But pH variations and salt addition don't change the haemocyanin secondary structure as shown by circular dichroism. The C.D. spectrum of scorpion haemocyanin exhibits the characteristic bands of Arthropod haemocyanine.


pH and the level of calcium in the blood of fetal and neonatal albino rats. Near-term rat fetuses in utero are acidotic and hypoxic, and have high levels of total serum calcium. In the first hour of postnatal life, pO2 and pH increase and pCO2 and calcium fall. Between 1 and 4 h following birth, respiratory gases vary little, whereas pH continues to rise and calcium further declines. By 4 h, newborns reach normal pH levels but are markedly hypocalcemic. It is suggested that the 'hypercalcemia' of intrauterine life is related to acidosis in utero, and that following birth, the initial fall in serum calcium is associated with the blowing off of CO2 and a concomitant rise in pH. The later decline in circulating calcium is independent of alterations in respiratory gases and relates directly to the final correction of neonatal acidosis.


Nasal continuous positive airway pressure. Improvement in arterial oxygenation in hyaline membrane disease. Continuous positive airway pressure (CPAP) was employed using nasal prongs in 30 neonates with hyaline membrane disease (HMD). There was a significant improvement in mean PaO2 (from 47 to 80 mmHg;p less than 0.001) with no significant change in PaCO2 or pH within a mean 36 min of therapy. Use of the technique allowed reduction of FiO2 to less than 0.60 in less than 20 h in 18 infants. Infants treated within 24 h of birth had significantly greater improvements in PaO2. Complications were infrequent and only 3 of 30 babies developed a pneumothorax while on nasal CPAP. Only 1 of the 23 survivors required mechanical ventilation in addition to nasal CPAP.


Lung lecithin biosynthesis in the nonhuman primate fetus: determination of the primary pathway in vivo. The two pathways for de novo lecithin (phosphatidylcholine) biosynthesis, choline incorporation (1) and phosphatidylethanolamine methylation (II), were examined simultaneously in lung and other tissues of Rhesus monkey fetuses. Cannulation of interplacental fetal vessels permitted studies on the intrauterine fetus without disruption of fetal-placental-maternal-amniotic fluid anatomic integrity. In contrast to observations with indirect techniques in the same species, direct measurement of the incorporation of isotopic precursors (3H-choline and 14C-ethanolamine) into lecithin indicated that pathway I predominates by 100-fold over PE methylation in pulmonary lecithin synthesis. Fetal liver, brain, and kidney also showed 10--70-gold greater choline incorporation that methylation activity. Measurement of lung phosphatidylcholine production via the two pathways in acidemic fetuses (umbilical venous pH less than 7.20) demonstrated marked inhibition of pathway I, but not II. It is concluded that the choline pathway is the major mechanism of lung lecithin synthesis in fetal primates and that this pathway is pH sensitive in vivo.


2,3-2, 3-.

2,3-2, 3-. Erythrocityc variations of glycolytic intermediates and 2,3-DPG levels in rabbits performing strenuous exercise under hypoxic conditions are correlated with blood pH variations. The hypoxia alone is not able to induce directly an increase of erythrocytic 2,3-DPG level which would facilitate tissue oxygenation.


Electrostatic interactions at charged lipid membranes. I. Effects of pH and univalent cations on membrane structure. Electrostatic interactions at charged lipid membranes make a significant contribution to the free energy of the system, and can be varied within a wide range by alteration either of the membrane's surface charge density or of the concentration of electrolytes in the surrounding medium. Changes in the charged membrane's structure, such as the ordered in equilibrium fluid phase transition, can thus be induced at constant temperature by variations in pH and salt concentration. An adequate quantitative description of these phenomena is obtained from the Gouy--Chapman theory. The good agreement between theory and experiment confirms that the expression derived for the electrostatic free energy especially in respect of its positive sign is correct. The classical expression derived for the electrostatic free energy, especially in respect of its positive sign, is correct. The classical expression for the "free energy of the double layer" derived by Verwey and Overbeek, which has a negative sign, is not applicable to lipid membranes with ionizable polar groups.


Formation of proteinoid microspheres under simulated prebiotic atmospheres and individual gases. The formation of microspheres from acidic and basic proteinoids was attempted under simulated prebiotic atmospheres and constituent gases thereof. Both types of proteinoid yielded microspheres under carbon dioxide, carbon monoxide, methane, hydrogen sulfide, hydrogen, nitrogen, and oxygen (tested separately) and also under nitrogen-carbon dioxide atmospheres; higher proportions of carbon dioxide resulted in fewer spheres from basic proteinoid. Neither type of proteinoid formed spheres on 10-minute exposure to ammonia or methane-hydrogen-ammonia atmospheres. (Brief exposure resulted in spheres from basic proteinoid.) The effects, both qualitative and quantitative, were indicated by control experiments to be due to pH, rather than to the specific gas (or ion). The results suggest that the proteinoid microsphere model for protocells is applicable under a variety of possible prebiotic atmospheres, with some restrictions imposed by pH.


Continuous regeneration of NAD(P)+ by flavins covalently bound to sepharose. Various flavins, FMN, FAD, and acriflavin, were immobilized to Sepharose using several different coupling methods. The only product stable enough to permit extended studies was acriflavin coupled to epoxy-substituted Sepharose. The nonenzymic oxidizing capacity towards NAD(P) H was investigated and a 25% specific activity, compared to that of free acriflavin, was observed. The reduced acriflavin was immediately auto-reoxidized in air and could thus be reused. It was shown that acriflavin-Sepharose preparations function as NAD(P)H oxidizing agents in a number of different dehydrogenase systems including lactate dehydrogenase (LDH), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), alanine dehydrogenase (alaDH), and glutamate dehydrogenase (GDH). The amount of expensive coenzyme necessary for high product formation of such systems was thereby markedly reduced.


["Lymph node" form of graft-versus-host reaction in mice]. Local type of the graft-versus-host reaction was induced in adult hybrid mice (CBA X C57BL) F1 by the transfer of splenic, thymus and bone marrow CBA cells subcutaneously into the right hind footpad. The weight gain of the regional knee lymph node and blast accumulation in it 7 days later were used as indices of the graft-versus-host activity. After the transfer of 5 and 20 x 10(6) splenic cells the absolute weight of the regional lymph node was 8-10 times higher than that of the contralateral control; it was also significantly greater in comparison with controls which received live syngeneic or semiallogeneic dead cells from the same source. Contrary to controls, in case of the live cells a direct dose-effect dependency could be seen. The lymph node weight gain was accompanied by a regular immunoblast accumulation. The effect of the thymus and the bone marrow cells was less pronounced than that of the splenic cells.


[Participation of mouse T- and B-lymphocytes in the graft versus host reaction]. Cells of the spleen or lymph nodes of CBA mice were transplanted to sublethally irradiated (CBAXC57BL/6)F1 mice; this caused development of the graft-versus-host reaction (GVHR). Lymphocytes lost the capacity to realize this reaction after in vitro treatment with specific sera against mouse T- and B-lymphocytes. Apparently, development of the GVHR in mice was connected with the cooperative interaction of T- and B-lymphocytes.


[Ribonuclease activity in preparations of human leukocyte interferon]. Preparations of human leukocyte interferon obtained by multi-stage purification procedure exhibited ribonuclease activity with the optimum at pH 7.0--7.5. The enzyme possessed the endonuclease action mechanism. Most substances studied for their effect on the RNA-ase activity in human interferon preparations showed many of them to act on the enzyme in the same way as on other ribonucleases. However, dithioerythritie, a reducing agent for disulfide bounds, activated the ribonuclease in the interferon preparation, as distinct from the pancreatic ribonuclease, which was inhibited by this preparation. Patterns of protein and RNA-ase distribution were obtained by electrophoresis in polyacrylamide gel.


[Genetic differences in lymphoid tissue reactivity during liver regeneration in mice of different lines]. The transfer of lymphocytes together with sheep erythrocytes from partially hepatectomized mice to syngenous lethally irradiated mice (CAB and C57BL) increased the number of antibody forming cells in the recipient's spleen. The lymphocytes of CBA mice acquired this ability much earlier after the operation (in 4 hours) than those of the C57BL mice (in 17 hours). After the transfer of lymphocytes in the semisyngenous system there was a decrease of antibody forming cells during subsequent recipient's immunization with sheep erythrocytes; this was the result of the graft versus host reaction. The latter reaction was less marked in the operated than in control mice. These changes also occurred earlier after the operation in the CBA than in C57BL mice.


[Distribution of lysosomal enzyme activity in cells of the renal cortical substance following transplantation of allogenic spleen cells under its capsule]. Allogenous spleen cells were transplanted subcapsularly into the kidney of mice irradiated in a dose of 650 r. The resulting damage of the kidney cortex structure was closely associated with the function of macrophages and with activation of the lysosomal enzymes.


Successful bone marrow transplantation against mixed lymphocyte culture barrier. If bone marrow transplantation is to become widely applicable in the treatment of patients with leukemia and aplastic anemia, the necessity to have a perfectly histocompatible donor must be overcome. In an effort to define the roles of HL-A type and mixed lymphocyte culture (MLC) reactivity in the determination of successful engraftment and the occurrence of graftversus-host disease (GVHD), we have attempted transplantation of a child with acute myeloblastic leukemia (AML) using an HL-A identical, MLC-reactive sibling donor. Successful engraftment has been accomplished, as documented by the appearance of multiple donor genetic markers in the recipient. There is no evidence of severe GVHD. The recipient is alive, without evidence of leukemia, and has returned to full activities 9 mo after transplantation. The recipient now produces lymphocytes, which have the MLC reactivity that characterize the donor's lymphocytes, rather than that of her own pretransplant lymphocytes. This experience demonstrates that successful bone marrow transplantation in patients with leukemia can be accomplished in the face of MLC reactivity.


Comparison of atenolol and propranolol during insulin-induced hypoglycaemia. The effects of atenolol, a new beta1-blocking drug, on pulse rate, sweating, and blood glucose levels during insulin-induced hypoglycaemia were studied in a double-blind crossover trial in eight normal subjects using placebo and propranolol as reference agents. The intensity of induced hypoglycaemia was identical for atenolol, propranolol, and placebo. Propranolol prolonged hypoglycaemia, but atenolol did not. Atenolol may therefore be safe for use in patients receiving insulin.


Comparison of propranolol, metoprolol, and acebutolol on insulin-induced hypoglycaemia. Metoprolol and acebutolol, two supposedly cardio-selective beta-adrenergic recptor blocking agents, were tested in healthy volunteers against propranolol, a non-selective drug, for their effect on blood glucose levels during insulin-induced hypoglycaemia. There was not significant difference between propranolol and metoprolol, which both potentiated the initial hypoglycaemic action of the insulin and delayed the return to normoglycaemia. Acebutolol, even though potentiating the initial hypoglycaemia, did not possess a significant delaying effect. A similar trial should be undertaken in diabetics to determine with certainty the safety of such drugs in diabetes mellitus.


Effect of atenolol on ventilatory and cardiac function in asthma. The effects on ventilatory and cardiac function of atenolol, a new cardioselective beta-adrenoceptor blocking agent, were compared with those of practolol in a double-blind trial in 12 patients with asthma. Both drugs impaired ventilatory function--atenolol insignificantly and practolol significantly. Atenolol was if anything more cardioselective than practolol. Neither drug interfered significantly with the bronchodilator response to inhaled isoprenaline. Atenolol is suitable for use in patients for whom practolol would formerly have been chosen because of its cardioselectivity.


Light-evoked release of glycine from cat and rabbit retina. The light-evoked release of [3H]glycine from retina in cat (in vivo) after pre-retinal perfusion and in rabbit (in vitro) after intravitreal injection was studied. The site of uptake of [3H]glycine into retina was checked by autoradiography and was found to be almost exclusively in a type of amacrine cells. If the retina loaded with [3H]glycine was stimulated by light flashes the release increased significantly in both in vivo and in vitro experiments. When the flashing light was exchanged for continuous light there was not change in the spontaneous efflux of radioactivity. Chromatographic experiments showed that the main part of the radioactivity released by light was glycine. The light-evoked release of glycine from retina was dependent on temperature and Ca2+. Low temperature (+2 to +4 degrees C) abolished the increased release. If Ca2+ was ommitted from the perfusion medium and EDTA was added there was no light-inducable change in the efflux of radioactivity in retinas loaded with [3H]valine. The present results, that light stimulation will release glycine from the retina both in vivo and in vitro, are further criterion for it as neurotransmitter.


Osteopetrosis of microphthalmic mice -- a defect of the hematopoietic stem cell.? The recessive genes mi and gl in the homozygous state determine, among other phenotypic effects, osteopetrosis in the house mouse. From a stock carrying mi derived from Grüneberg (1963) the mi gene was bred into the standard CBA/H inbred strain. Microphthalmic mice of these two stocks and their hybrids were treated as newborn by intraperitoneal injection and at weaning or maturity by intravenous injection of cell suspensions containing hematopoietic stem cells from phenotypically normal mice. Resolution of much of the osteopetrosis but not the other phenotypic effects occurred within a few months in the majority of cases, provided syngeneic or H-2 compatible allogeneic cells were given: it did not occur spontaneously or on giving H-2 incompatible cells or on giving compatible material by an inappropriate route. The results accord with hypotheses that (1) osteoclasis of scaffoldtype woven bone is impaired in mi mi, (2) that osteoclastic cells are derived through circulating monocytes from hematopoietic stem cells, and (3) in mi mi this defect can be overcome by a transplant of normal hemopoietic stem cells.


Metabolism of (4-14C)estrone by sheep erythrocytes around the time of parturition. The metabolism of [4-14C]estrone in vitro by red blood cells of sheep in late pregnancy and after partuirition has been studied. [14C]estrone (600 ng) was incubated with 0.5 ml erythrocytes plus 0.5 ml of Krebs-Ringer phosphate buffer, pH 7.4, for 2 h at 37 degrees C in an atmosphere of air. After incubation, [3H]estrogens were added to the incubation medium as internal standards for identification and for correction for procedural losses. Metabolites were isolated and purified by chromatography, acetate derivative formation, and recrystallization to a constant 3H/14C ratio. Approximately 20% and 2% of added estrone were converted to 17beta-estradiol and 17 alpha-estradiol, respectively. The remainder was recovered unchanged. Daily measurements of 17 beta-hydroxysteroid dehydrogenase activity in erythrocytes of five ewes, over the period 8 days prepartum to 4 days postpartum, showed no significant change in activity.


[Biosynthesis of glycoproteins in pulmonary parenchyma. II. Galactosyltransferase activity in pneumocyte subcellular fractions]. A soluble galactosyltransferase exists in the cell sap of the alveolar cells of the lung. The optimal conditions of galactosyltransferase are: pH 6, 20 DEGREES C, 10 mM Mn2+, 1 mM Mg2+. Michaelis constant for substrate UDP-galactose is 390 nM. By electrofocusing on Ampholine column, galactosyltransferase appears in a unique peak, at pHi 4.8. The parameters of the purified enzyme are the same as that of the crude enzyme. UDP is a noncompetitive inhibitor for the purified enzyme.


The influence of beta-adrenergic antagonists on the adrenergic responses of the rat vas deferens. The influence of beta-adrenergic antagonists (propranolol, pronethalol, alprenolol, isopropylmethoxamine, H 35/25, sotalol and practolol) on isotonic contractile responses to norepinephrine (NE) was studies. All drugs caused an increase in the maximum responses while depressant effects were seen only with high doses of propranolol, pronethalol and alprenolol. The enhancement of responses to NE was considerably greater at low concentrations of calcium (0.5-1.0 mM) than at high (8 mM) concentrations. The inhibitory effects of propranolol, pronethalol and alprenolol were diminished but not completely overcome by increasing calcium concentrations form 1.8 to 8 mM. Cumulative dose-response curves of calcium showed no increase in maximum responses although responses to low concentrations of calcium were augmented by sotalol and practolol. Evidence suggests that the enhancing effects of these drugs may be due to their facilitatory effect on calcium mobilization following alpha-adrenoceptor activation while their depressant properties probably reflect their membrane stabilizing properties.


Effect of hypothyroidism on responsiveness to beta-adrenergic stimulation. Chronic administration of aminotriazole (0.5 g/kg food) to rats was accompanied by a reduced responsiveness to acute administration of the beta-adrenergic agonist, l-isoproterenol (50-100 mug/kg, sc). The responses tested included water intake, change in heart rate in the anesthetized and unanesthetized rat, change in mean blood pressure, and change in blood glucose concentration. In addition, the increase in tail skin temperature accompanying administration of epinephrine (1 mg/kg, sc) was significantly reduced in the hypothyroid group. Administration of l-thyroxine (25 mug/kg per day, ip) to aminotriazole-treated rats prevented the reduction in responsiveness to beta-adrenergic stimulation. Thus, an interaction appears to exist between the level of thyroid activity and responsiveness to beta-adrenergic agonists in rats.


Effects of alpha-adrenergic blockade on sodium excretion in normal and chronic salt retaining dogs. The alpha-adrenergic blocking agent phenoxybenzamine (PBA) was administered intravenously (10 mug kg-1 min-1) during a steady state water diuresis under pentothal anesthesia to six normal dogs, six dogs with chronic throacic inferior vena cava constriction and ascites (caval dogs) and seven dogs chronically salt depleted by sodium restriction and furosemide administration. In normal dogs urinary sodium excretion increased significantly from 265+/56 (SEM) to 370+/65 muequiv./min, whereas no increase in sodium excretion was noted in either caval dogs or salt depleted animals after PBA. In all three groups urine volume, fractional free water clearance and distalsodium load did not change significantly. In normal dogs, tubular sodium reabsorption decreased significantly from 73.4+/2.8% to 63.1+/4.0%, whereas no change was noted in caval or salt depleted dogs. Blood pressure and renal hemodynamics were not significantly altered by PBA administration in any group. These data demonstrate a natriuretic effect of alpha-adrenergic blockade in normal dogs with the major effect in the water clearing segment of the nephron. The absence of any effect in chronic caval or salt depleted dogs suggests that increased alpha-adrenergic activity does not play a significant role in the sodium retention of these animals.


Effects of catecholamines injected into the septal area of the rat brain on natriuresis, kaliuresis and diuresis. Urinary output of Na+ and K+, and volume of urine have been studied in conscious, unrestrained, water-loaded male rats following the intraseptal injection of catecholamines. Natriuresis and kaliuresis increased after injecting noradrenaline (NA), the intensity being dose related. The dose-response curve suggests that a monomolecular interacting takes place between NA and pharmacological receptors present in the septal area. No change was observed in diuresis. Systematic mapping of the septal area yielded about the same results for all sites except a zone located in the lateral nucleus that was more sensitive. An alpha blocker (dibenamine), injected intraseptally before NA, showed an inhibitory effect while a beta blocker (propranolol) yielded a potentiation effect. These same effects of the blocking agents were observed when adrenaline was used instead of NA. Lidocaine, which inhibits the re-uptake of NA, showed an enhancement of the natriuretic and kaliuretic effect of NA, and the same effect was observed when the enzymatic destruction of NA was prevented by nialamide, an inhibitor of monoaminoxidase. Dopamine showed a natriuretic effect, but no effect was observed on K+ and urine output. Serotonin had no action on natriuresis, kaliuresis and diuresis.


Critical opening pressure and reactivity of tail vessels in conscious hypertensive rats. The possible role of increased vascular reactivity in the mechanism of experimental hypertension was studied by measurements of the critical opening pressure (COP) of tail vessels in conscious rats. In hypertension induced by administration of desoxycorticosterone acetate (DOCA) and replacement of the drinking water by 1% NaCl solution (DOCA-NaCl hypertension), and in one-kidney Goldblatt renovascular hypertension, the raised level of blood pressure was associated with an increased COP of the tail vessels when measured both before and after ganglionic blockade. In rats treated with either DOCA alone or 1% NaCl alone there was no significant increase in systolic blood pressure (SBP) or COP relative to the corresponding controls. In all four experimental series intravenous infusion of angiotensin or norepinephrine in conscious ganglion-blocked rats produced dose-dependent increases in SBP and COP. In DOCA-NaCl hypertensive rats but not in renovascular hypertensives, nor in rats treated with DOCA alone or 1% NaCl alone, the increase in COP for a given increment in dose of angiotensin or norepinephrine was significantly greater than in the control rats. It is concluded that in DOCA-NaCl hypertension there is a true increase in the reactivity of the smooth muscle of the resistance vessels to angiotensin and norepinephrine. In renovascular hypertension this is not the case and other factors must therefore be involved in causing the increased blood pressure and COP.


Effects of isoproterenol on cyclic-AMP metabolism in rat ventral prostate. Beta-Adrenergic stimulation of the ventral prostate cyclic-AMP system was investigated by examining the influence of isoproterenol on endogenous cyclic-AMP levels as well as on the activities of adenylate cyclase CEC 4.6.1.1) and cyclic-AMP-dependent and independent protein kinases (EC 2.7.1.37). Administration of isoproterenol (1 mg/kg, ip) resulted in rapid elevation of adenylate cyclase activity (119%) and cyclic-AMP levels (593%). The observed isoproterenol-stimulated changes in cyclic-AMP metabolism of the ventral prostate were time-dependent and maximal stimulation was seen 5 min after treatment with this beta-adrenergic agonist. The increases in prostatic adenylate cyclase and cyclic-AMP also were related to the dose of isoproterenol administered and maximal enhancement of these parameters was seen with 1 mg/kg dose of the agonist. Whereas pretreatment of rats with propranolol (3mg/kg, ip) partially reversed these alterations, administration of an alpha-adrenergic antagonist, phentolamine, even at a dose of 5 mg/kg, failed to elicit any appreciable effect. Stimulation of prostatic soluble protein kinase by isoproterenol was associated with a decrease (33%) in the activity of the cyclic-AMP-dependent protein kinase with a concomitant increase (25%) in that of the independent enzyme. Whereas the ability of the enzyme to bind cyclic-(3H) AMP in vitro was decreased (54%) following isoproterenol treatment, the protein kinase activity ratio (-cyclic-AMP/+cyclic AMP) was significantly elevated from 0.51+/0.05 to 0.95+/0.08. Although propranolol alone had little or no effect on these parameters, it inhibited partially the isoproterenol-induced alterations in cyclic-AMP-dependent protein kinase and the cyclic-AMP binding capacity. Treatment with propranolol also blocked the increases in the kinase activity ratio and in the activity of cyclic-AMP-independent enzyme seen with isoproterenol. Data suggest that the concentration of ventral prostate cyclic-AMP  as well as the activities of adenylate cyclase and cyclic-AMP-dependent and independent form of protein kinases are subject to modulation by beta-adrenergic stimulation.


Epinephrine-induced hepatic potassium movements before and after adrenergic blockade. The epinephrine-induced loss and subsequent uptake of K+ by the liver was studied by measuring hepatic arterio-venous K+ differences and splanchnic blood flows in anesthetized dogs with chronically implanted portal vein catheters and celiac and superior mesenteric artery flow probes. When epinephrine was administered intraportally, neither alpha- nor beta-adrenergic blockade, singly or in combination, had significant effects upon the hyperkalemic or the hypokalemic phases in either hepatic venous or systemic arterial blood. It was concluded that the movements of K+ into and out of the liver caused by epinephrine are not mediated by the classical adrenergic receptors as defined by inhibition by specific blocking agents.


Blockade of histamine-induced contractions of guinea pig ielum by beta-haloalkylamines. In the longitudinal muscle strip of guinea pig ileum phenoxybenzamine (POB) produces a maximum parallel shift of 0.7 log units in the dose-response curve to histamine. In the presence of sodium thiosulfate in the wash fluid the parallel shift whith retention of maximum response increases to about 2 log units, and a similar value is obtained for Nethyl-N-(2-bromoethyl)-1-naphthylamine. The The agent N-ethyl-N- (2-chloroethyl)benzylamine produces a significantly smaller shift of dose-response curve of 1.53 log units before the maximum response becomes depressed. The receptor-specific depression of maximum response produced by higher doses of POB is reversed by sodium thiosulfate and by bovine serum albumin, while the parallel shift in dose-response curve is unaffected by both treatments. These findings may be explained by a hypothesis involving interaction of 2-haloalkylamines at two sites.


Postsplenectomy sepsis due to influenzal viremia and pneumococcemia. A 31-year-old man, who had undergone splenectomy 18 months previously because of hereditary spherocytosis, suddenly became ill, with fever, vomiting, epigastric pain and shock, and died 10 hours after the onset of his symptoms. Autopsy showed influenzal viremia, pneumococcemia and bilateral adrenal hemorrhage. The rapid course of the patient's illness emphasizes the serious risk of sepsis for individuals who have had a splenectomy. Anti-influenza immunization in such patients should be considered.


Malignant germ cell tumor in situ in a cryptorchid testis. A case of a malignant undifferentiated germ cell tumor in situ of an undescended testis diagnosed by needle biopsy is described. Four similar cases have been so far recorded in the literature, all of them in the infertile men with normally descended descended testes. Two of them developed embryonal carcinoma of testis 4 1/2 later and one had a concomitant seminoma. In a high-risk group of patients (atrophic testis, cryptorchidism), a needle biopsy of a testicle may discover malignancy in its very early phase of development (Stage 0), at which time an orchiectomy alone may be a curative treatment.


Understanding neurotransmitters and related drugs. Chemical neurotransmitter substances are released at the axon terminals of the central, autonomic, and peripheral nervous systems of the human body. The most well-known of the neurotransmitters are acetylcholine, norepinephrine, dopamine, and serotonin. It is these substances that facilitate the conduction of nerve impulses throughout the body, allowing the coordination of body functions and enabling response to the environment. The efective action of neurotransmitters makes the difference between health and disease states. A nurse's understanding of neurotransmitters and of many common drugs influencing their function is essential to safe nursing practice.


Muscular work and the release of prostaglandin-like substances. Experimental evidence for the release of prostaglandin-like substances, mainly of the E type, into the venous outflow from working skeletal muscles in the dog is described. Muscular exercise of the hind-leg produced by sciatic nerve stimulation evoked the release of prostaglandin-like substances detected in femoral venous blood by the bioassay method. This release occurred during and after muscular work, was abolished by indomethacin, and was not present in gallamine-treated dogs. The results suggest that endogenous vasodilator prostaglandins released during and after muscular work may contribute to local hyperaemic response during and, mainly, after muscular activity.


Fine structure of complex ocelli of a cubomedusan, Tamoya bursaria Haeckel. The retina of the distal and proximal lens-bearing complex ocelli are composed of pigmented sensory cells and long pigmented cells. A ciliary sheath from each sensory cell, together with the processes of long pigmented cells, extends through the vitreous layer as far as the capsule that envelops the lens. Each ciliary sheath has several ballon-like swellings and the ciliary microtubules, arranged in the 9+2 pattern in the proximal part, are markedly disorganized distally in the swollen parts, out of which extends most of the microvilli in the vitreous layer. It is suggested that some of the microvilli may originate in vesicles that are constricted off from the surface of the pigmented sensory cells. Closely packed microvilli run in parallel in short bundles. In addition to characteristic junctions between sensory cells, junctions that are presumably synaptic and, of a new type in coelenterates, are observed between sensory cells and nerve endings.


The mechanism of action of ppGpp on rRNA synthesis in vitro. We have studied the mechanism of the specific inhibition of ribosomal RNA synthesis by ppGpp in a purified system using as templates E. coli DNA and DNA from lambdad5ilv, which carries a rRNA cistron from E. coli. Ribosomal RNA synthesis, as well as its inhibition by ppGpp, are critically salt-dependent. Of a number of guanosine phosphates tested, only pppGpp (MS II) mimicked the action of ppGpp, establishing the specificity of ppGpp. The two templates gave similar results for rRNA synthesis in all experiments. By using the initiation inhibitor rifampicin, we could show that the specific inhibition of rRNA synthesis by ppGpp is due to its effect on rRNA initiation. The somewhat variable inhibition of RNA synthesis in general by ppGpp is mainly or wholly a consequence of premature chain termination. We propose that ppGpp specifically inhibits rRNA synthesis by acting on the formation of the so-called "closed-promoter complex".


Glutamine-stimulated modification and degradation of glutamine synthetase in hepatoma tissue culture cells. Effects of glutamine on glutamine synthetase (GS) activity of hepatoma tissue culture (HTC) cells were studied with the aid of a specific goat anti-rat GS serum. Immunodiffusion and immunoelectrophoretic tests show that rat liver GS and HTC cell GS are immunologically similar but not identical. Immunotitrations of HTC cell extracts demonstrate that in cells incubated in high concentrations (5 mM) of glutamine, a cross-reacting form of GS with a decreased enzyme-specific activity accumulates. On prolonged incubation of cells in high glutamine, there is net degradation of GS to form immunologically inactive products. Radio-immunoprecipitation experiments show that glutamine acts by accelerating the degradation of preformed GS.


Membrane receptors for murine leukemia viruses: characterization using the purified viral envelope glycoprotein, gp71. The 71,000 dalton glycoprotein (gp71) purified from Rauscher murine leukemia virus (R-MuLV) by affinity chromatography specifically binds to murine but not other mammalian cells in culture. Binding is prevented by specific antiserum raides to gp71 (anti-gp71). The binding assay as described in this report can detect receptors on as few as 300 murine cells, and with 1 X 10(5) cells gives significant binding with 30 sec. The results show that the purified glycoprotein retians biologic activity and can form a stable complex with specific receptors on mouse cell membranes. The assay can therefore be used to characterize the nature of the cellular receptors that are essential for leukemia virus infection. Purified gp71 binding to mouse cells is prevented if the cells are actively producing related ecotropic type C viruses, presumably because the receptors are occupied and are not available to bind exogenously applied gp71. The binding of gp71 to murine cells is enhanced by the presence of calcium ions and low pH. Binding studies performed using an excess of 125I-gp71 indicate the NIH/3T3 cells bind approximately 5.3 X 10(5) molecules of 125I-gp71 per cell.


Naturally occurring cross-links in yeast chromosomal DNA. Chromosome-size yeast DNA molecules with a number average molecular weight (Mn) of 3-4 X 10(8) were isolated from sucrose gradients after sedimentation of lysed yeast spheroplasts. Resedimentation showed that the molecules were isolated without introducing appreciable single-strand or double-strand breaks. The presence of cross-links in these molecules was suggested by the observation that the apparent Mn in alkali was greater than expected for separated single strands. Since cross-linked molecules would have strands which fail to separate upon denaturation, this was tested more directly. Neutralization of alkaline denaturing conditions resulted in up to 70% of the intact molecules rapidly reforming duplex structures, as shown by equilibrium banding in CsCI. Experiments with larger E. coli DNA molecules (Mn = 5.2 X 10(8)) indicated that the conditions used were sufficient to denature completely molecules of this size. Results of enzyme treatments suggest that the cross-links are not RNA or protein. Experiments with density-labeled yeast DNA molecules showed that the rapid reformation of duplex DNA is not the consequence either of a bimolecular reaction between separated DNA strands or of intrastrand renaturation. The data indicate that when the yeast DNA molecules are completely denatured, the strands fail to separate. Hence they must be cross-linked. Experiments with sheared DNA show that there are small number of cross-links, one to four, permolecule.


The effect of allyl compounds on hepatic microsomal mixed function oxidation and porphyrogenesis. The activities of 5-aminolaevulinate (5-ALA) synthetase and of various microsomat drug-metabolising enzymes have been determined in the livers of rats pretreated with different drugs and chemicals containing the allyl group. Safrole, isosafrole and secobarbital gave rise to slight increases in 5-ALA synthetase, whereas alclophenac and triallyl cyanurate almost doubled the enzyme activity and the known porphyrogenic agents, allylisopropylacetamide (AIA) and allobarbital caused increases of 1.5- and 2.5-fold, respectively. Allobarbital induced the microsomal drug-metabolising enzymes while secobarbital had only a weak effect and alclophenac and triallyl cyanurate had no effect at all. From these results it is suggested that induction of the synthesis of cytochrome P-450 is not rate dependent on the synthesis haem and induction of porphyrin biosynthesis.


The action of a binary nonionic detergent on a kidney membrane fraction. The disruption of a kidney cortex microsomal membrane preparation by a binary, nonionic detergent, was followed by using as markers, the changes in total protein content, and (Na+, K+)-ATPase in a supernatant fraction. Both markers responded similarly to changes in pH, microsome concentration and detergent concentration, but responded differently for time-dependent studies. The (Na+, K+)-ATPase activity was increased 2.2-fold (76.1 mumoles Pi/mg protein/h, 95% ouabain-sensitive) by a single detergent treatment and 3.5-fold (92% ouabain-sensitive) by a sequential detergent treatment. Changes in the critical micelle concentration (cmc) were observed for varying detergent and protein concentrations, which suggest interactions of monomeric detergent with the membrane. The peak of (Na+, K+)-ATPase activity occurred above the cmc which suggests the participation of micelles in releasing the enzyme from the membranes. Hill plots of the protein released as the detergent concentration was varied showed a change in the slope near the cmc indicating a four-fold increase in the binding of detergent to membranes as the detergent concentration is increased above the cmc. These results suggest that the disruption of membranes by detergent involves the binding of detergent monomers to the membrane followed by the formation of co-micelles of the detergent with segments of the membrane to complete the separation process.


Resistance of alkylated DNA to degradation by deoxyribonuclease II at neutral and acid pH. Methylation of a calf thymus DNA substrate by dimethyl sulphate (DMS) leads to an inhibition of deoxyribonuclease II activity which is gradually lost with time. The extent of this initial inhibition is linearly related to the amount of methylated products in DNA and quantitatively similar effects were found when the enzyme was used under either acid or neutral conditions. Deoxyribonuclease II was shown to produce 3'-phosphate termini under both acid and neutral conditions and thus, irrespective of the ionic conditions for the action of this enzyme in vivo the effects demonstrated here are of potential significance. Local denaturation of the methylated DNA may be partly responsible for these inhibitory effects but it is likely that the methyl purines also play a more direct role.


Enzymatic properties of native and N-ethylmaleimide-modified cardiac myosin from normal and thyrotoxic rabbits. Cardiac myosin from thyrotoxic animals (myosin-T) exhibits elevated Ca2+ -ATPase activity which is resistant to further stimulation by sulfhydryl modification. In the present study, we have compared the enzymatic properties of myosin-T with those of myosin from euthyroid rabbits (myosin-N) and the derivatives of myosin-T and myosin-N formed by blocking the most rapidly reacting class of thiols (SH1) with N-ethylmaleimide (NEM). Vmax for Ca2+ -ATPase of myosin-T was about 250% greater than myosin-N and was nearly the same as NEM-modified myosin-N. Values for the apparent Km of myosin-T and NEM-modified myosin-N were 200% greater than the value for unmodified myosin-N. Vmax and Km for K+ (EDTA)-ATPase activity of NEM-modified myosin-T and myosin-N were identical. The Ca2+ saturation, pH, and salt-dependency curves for the ATPase activity of myosin-T were parallel to the curves for myosin-N and differed from those for the NEM-modified myosins. Myosin-T exhibited an increased rate of hydrolysis of ATP, CTP, and UTP in both low (0.05m) and high (0.5m) KCl medium. NEM-modified myosin-N showed increased hydrolysis of ATP and CTP in low KCl medium and increased hydrolysis of ATP, CTP, and UTP in high KCl medium. These results support the hypothesis that the enzymatic behavior of myosin-T may be caused by an alteration in the active site near the SH, thiols. The unique enzymatic properties of myosin-T did not seem to be the result of a major change in structure. The electrophoretic pattern of light chains from myosin-T and myosin-N was the same in polyacrylamide gels containing either 8 M urea at pH 8.6 or sodium dodecyl sulfate. Also, myosin-T had a normal amino acid composition and lacked 3-methyl-histidine and hot acid-stable phosphate.


The association between serum triglycerides and gamma glutamyl transpeptidase activity in diabetes mellitus. A study conducted on 228 diabetic patients has shown a significant positive association between serum gamma-glutamyl transpeptidase (GGT) and triglyceride levels. Both fall with treatment, the most marked reduction occurring in patients on insulin. We suggest that the association between serum GGT and triglyceride levels and also the higher incidence of raised GGT and triglyceride levels in new diabetics may reflect hepatic microsomal enzyme induction of the rate-limiting enzymes of triglyceride synthesis. Serum GGT does not seem to correlate with hepatomegaly in diabetes mellitus.


Reverse-phase chromatography of polar biological substances: separation of catechol compounds by high-performance liquid chromatography. Catecholamines and their metabolites have been separated isocratically by reverse-phase chromatography with aqueous (no organic solvent admixed) eluents. Unlike ion-exchange or ion-pair chromatography, mixtures of both acidic and basic substances can be separated in a single chromatographic run, because the retention is governed by hydrophobic interactions between the nonpolar moiety of the solute molecules and the octadecyl-silica stationary phase. The relative retention values strongly depend on the pH of the eluent, which governs the degree of dissociation of ionogenic solutes. The reproducibility of the results and the stability and efficiency of the chromatographic systems make this approach particularly attractive for use in clinical analysis.


Diagnosis of infectious hepatitis by multicomponent analysis with use of field ionization mass spectrometry. Field ionization mass spectrometry has been applied to multicomponent analysis of metabolites in human urine for the diagnosis of metabolic disorders, exemplified here by infectious hepatitis. The molecular weight profiles of carboxylic acids and of "neutral" metabolites in the urine of patients with infectious hepatitis were compared with those in urine of normals. The "neutral" metabolites showed 24 characteristic spectral differences in the range 68 to 215 atomic mass units, which provided correct diagnoses in 100% of the cases and a "diagnostic power" of unity. These results are even more encouraging than those obtained earlier with the acidic metabolites, where 11 mass numbers were found in the same mass range to be useful for correct diagnoses in 91% of the cases. The measurements were performed on urine samples preextracted on Amberlite XAD-2 columns. We used a quadrupole mass spectrometer interfaced with a multichannel analyzer for mass analyses.


Reversed-phase liquid-chromatographic analysis of hemodialysate from uremic patients. With reversed-phase high-performance liquid chromatography we effected rapid and efficient separation of metabolites present in hemodialysate fluid from uremic patients on the artificial kidney. With an aqueous sodium acetate/methanol gradient as mobile phase, more than 50 ultraviolet-absorbing constituents were resolved in a 70-min chromatogram of a 100-mul sample of dialysate. Many of the metabolites could be detected in concentrations below 0.1 mg/liter. From results of ultraviolet spectrophotometric analysis and the gas- and liquid-chromatographic properties of standards, half the observed chromatographic peaks have been characterized or identified. The method has been shown to be more than 10-fold faster than comparable separations by ion-exchange techniques.


Human leukocyte acid hydrolases: characterization of eleven lysosomal enzymes and study of reaction conditions for their automated analysis. The optimal reaction conditions and kinetic properties of eleven leukocyte acid hydrolases determined with the use of fluorigenic derivatives of 4-methyl-umbelliferone are described. The enzymes studied were acid phosphatase, aryl sulfatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucuronidase and alpha-fucosidase. More than 90% of the activity of each enzyme was released into a 27,000 X g supernatant by a double sonication procedure employing 0.9% sodium chloride and 0.1% Triton X-100. The Km values obtained were similar to those previously reported for chromogenic subtrates. A single Km value could not be derived for beta-galactosidase because its double reciprocal plot was not linear. All enzymes could be measured with less than 10 mug of protein within 15 min. Activators and inhibitors studied included the chloride salts of Na+, K+, Zn2+, Ca2+, Mg2+, Hg2+, and Fe2+ as well as p-chloromercuriphenysulfonate, glutathione, BAL, EDTA, EGTA, Triton X-100 and sodium taurocholate. The reaction conditions described in this report can be used for the diagnosis of various lysosomal storage diseases and should facilitate the development of automated procedures for the analysis of these eleven enzyme activities with small quantities of blood.


Oestrogen induced hypertriglyceridaemia: role of the adrenal cortex. The role of the adrenal cortex in the pathogenesis of hypertriglyceridaemia associated with the intake of oral contraceptive agents containing oestrogen has been investigated in rats. Bilateral adrenalectomy reduced the activity of hepatic enzymes regulating lipogenesis (acetyl CoA carboxylase, fatty acid synthetase) and decreased plasma triglyceride concentrations. On the other hand, the administration of high dosage corticosterone induced the activity of hepatic enzymes with consequent elevation in serum triglyceride levels. In animals with intact adrenals the administration of oestradiol: (a) raised plasma triglyceride levels, (b) enhanced the activity of hepatic enzymes, and (c) increased the adrenal cortex:body weight ratio. The effects (a) and (b) were not observed when both adrenals were removed prior to oestrogen therapy. High dosage corticosterone replacement was found to be essential for the oestradiol to produce its effects on hepatic enzymes and plasma triglyceride levels. The results suggest a regulatory role for the adrenal cortex in the homeostasis of plasma triglyceride concentration and that the hypertriglyceridaemia induced by the oestrogen containing preparations might be secondary to alterations in adrenocortical function.


Increased survival times of New Zealand hybrid mice immunosuppressed by graft-versus-host reactions. New Zealand mice develop autoimmune disease usually accompanied by glomerulonephritis. A graft-versus-host reaction was induced in New Zealand Black X New Zealand White F1 hybrid mice by administration of New Zealand White spleen cells. The mice so treated had diminished antibody responses to both an exogenous antigen (sheep red blood cells) and an endogenous antigen (native DNA).  They had much less glomerulonephritis and increased survival times compared to unmanipulated controls, apparently due to immunosuppression. Similar hybrid mice treated with high doses of cyclophosphamide (70mg/kg/week) were more immunosuppressed than mice with graft-versus-host reactions and had even greater survival times.


Organic acidemias.

Organic acidemias. Inherited organic acidemias are a group of metabolic disorders currently being described and investigated as gas-liquid chromatography is applied to unexplained diseases of infancy and childhood. Common clinical presentations include attacks of ketoacidosis, unexplained metabolic acidosis, failure of normal development, seizures, and other neurologic abnormalities. Hyperglycinemia, hyperammonemia, and hypoglycemia are other laboratory findings frequently present. Diagnosis depends on examination of urine, and sometimes blood, by gas-liquid chromatography to measure concentrations of organic acids and organic acid derivatives. Prognosis in many cases is excellent if diagnosis is made promptly and the metabolic acidosis can be reversed. Recovery from neurologic deficits has frequently been seen. Long-term therapy is generally dependent on restricting precursors of the toxic organic acid which builds up as a consequence of the enzyme deficiency. If there is some enzyme activity retained or if alternate metabolic pathways exist, success with therapy is likely.


Antihypertensive action of propranolol in man: lack of evidence for a neural depressive effect. The hypothesis that a neural depressive action is related to the antihypertensive effects of beta blockers has been evaluated in 14 essential hypertensive male patients through the circulatory response to noxious stimuli. The pressor reaction to mental arithmetic was primarily mediated by cardiac stimulation (beta receptors activation), that to cold by vasoconstriction (alpha receptors activation). Arithmetic and cold were tested to separate the effects of peripheral beta blackade from possible neural and other influences. After propanolol (320 mg per day for 3 wk): (1) The baseline pressure was reduced; (2) appearance, peak, and disappearance time of the circulatory reaction to either stimulus was not altered; (3) the pressor effect of arithmetic was decreased in an extent proportional to the reduced rise of cardiac output; and (4) pressure during cold reached the pretreatment levels through an augmented increase of vascular resistance. Our findings indicate that propranolol depresses only the circulatory reactions mediated through beta receptors activation and provide no evidence of effects other than beta blockade.


Calcificaiton of growth plate cartilage with special reference to studies on micropuncture fluids. No final comprehensive hypothesis of the chain of events involved in inhibition of calcification can be constructed at the present time. The flow diagram in Figure 1 is presented only as a working hypothesis currently used by the authors. Insofar as the Cfl is representative of native factors at calcifying sites, none of the major theories on the nature of mineral formation at present seem excluded. As in the fields of clotting and complement pathways, where backup systems seem to operate, one should not be surprised if more than one system operates in cartilaginous calcification.


Clinical pharmacokinetics of lorazepam. I. Absorption and disposition of oral 14C-lorazepam. Eight healthy male subjects received single 2-mg oral doses of lorazepam containing 24 muCi/mg of 2-14C-lorazepam. Multiple venous blood samples were drawn during the first 96 hr after the dose, and all urine and stool were collected for 120 hr after dosing. Concentrations of lorazepam and its metabolites in body fluids were determined by appropriate analytic techniques. Following a lag time, lorazepam was absorbed with an apparent first-order half-life of 15 min. The peak plasma concentration was 16.9 ng/ml, measured in the pooled sample drawn 2 hr after the dose, This corresponded to the time at which clinical effects appeared to be maximal. The apparent elimination half-life of lorazepam was about 12 hr. Biotransformation to a pharmacologically inactive glucuronide metabolite appeared to be the major mechanism of lorazepam clearance. A mean of 88% of administered radioactivity was recovered in urine, and 7% was recovered in stool. Lorazepam glucuronide comprised 86% of urinary reactivity; its renal clearance was 37 ml/min. Other identified metabolites included hydroxylorazepam, a quinazolinone derivative, and a quinazoline carboxylic acid; all of these were quantitatively minor.


Effect of age on oxygen-binding in normal human subjects. 1. Oxygen-binding, plasma and intra-erythrocytic pH, and haemoglobin, 2,3-diphosphoglycerate and inorganic phosphate concentrations were measured in sixty-two healthy non-smokers aged between 18 and 89 years. 2. P50 (oxygen tension at 50% oxygen saturation) expressed at plasma pH 7-40 and PCO2 5-33 kPa showed a positive correlation with age. 3. This correlation of P50 with age was closer when P50 was expressed at a constant intra-erythrocytic pH 7-20. On average P50 at intra-erythrocytic pH 7-20 increased from 3-59 kPa at 20 years to 3-96 kPa at 90 years of age. 4. 2,3-Diphosphoglycerate, inorganic phosphate, haemoglobin and mean corpuscular haemoglobin concentrations did not correlate with P50 or with age.


Intracellular acid-base heterogeneity in nucleated avian erythrocytes. 1. Intracellular hydrogen ion activity, [H+]i, was extimated in human erythrocytes and in nucleated avian erythrocytes from measurements of the distribution of ammonia and 5,5'-dimethyloxazolidine-2,4'-dione (DMO) between intracellular and extracellular fluid. 2. In human erythrocytes there was no difference between values for [H+]i derived from measurements of either DMO or ammonia. 3. In avian erythrocytes, [H+]i(ammonia) was consistently greater than [H+]i(DMO), indicating significant acid-base heterogeneity of the intracellular water. The degree of heterogeneity was assessed by reference to a theoretical model of two compartments of equal size. 4. Experiments with nuclei isolated from avian erythrocytes suggested that DMO is not bound to nucleoproteins, and that the nucleus may be more acidic than the cytoplasm.


Telephone management of poisonings using syrup of ipecac. Seven hundred and seventy-six cases were studied during a six-month period to see if induction of emesis could be successfully managed at home by telephone. Emesis was successful in 98.8% of cases. In 6.7% of all cases, symptoms were found at 4-hour follow-up that were referrable to the ingestion, but all were considered to be of minor consequence. No complications of vomiting occurred. Twenty-four hour follow-up investigation indicated no significant complications of induction of emesis or complications from managing the patient by telephone. It is our conclusion that, with appropriate telephone supervision, home-induced emesis of ingestions expected to produce mild to moderate symptoms is as effective as emergency room or physician office management of cases. Furthermore, the absence of adverse affects of complications arising from the induction of emesis at home in our cases confirms that this form of management is quite safe.


Cyclic AMP and cyclic GMP in epidermal physiology and pathophysiology. The second messengers cyclic AMP and cyclic GMP in several organs appear to coordinate those molecular events which are responsible for specialized organ function. As a result of balanced cell proliferation and specialization, epidermis functions by terminal specialization which provides a barrier between man and environment. Since the epidermal component of psoriasis is a classic example of deranged epidermal homeostasis, which has a low level of cyclic AMP and a high level of cyclic GMP, it seems reasonable that rebalancing these cyclic nucleotides might ultimately be a safe and effective therapy for psoriasis and other proliferative skin diseases.


Pleural fluid pH in parapneumonic effusions. The pH and carbon dioxide tension were measured in 24 consecutive parapneumonic effusions, along with the leukocyte count, leukocytic differential count, and levels of glucose and protein. Three categories of parapneumonic effusions were characterized: (1) empyemas; (2) benign (nonloculated) effusions; and (3) loculated effusions. A pH greater than 7.30 was present in all ten benign effusions, and spontaneous resolution occurred in each case. All ten empyemas and the four loculated effusions had a pH less than 7.30. All four loculated effusions required drainage with a chest tube for resolution. The pH of the pleural fluid alone separated the empyemas and loculated effusions from benign effusions. The early separation of parapneumonic effusions on the basis of the pleural fluid appears useful. If the pH is greater than 7.30, a benign effusion is present, and spontaneous resolution is likely. If the pH is less than 7.30, loculation of the pleural space may occur regardless of whether the effusion fulfills the criteria for empyema.


Lipid binding of a halothane metabolite. Relationship to lipid peroxidation in vitro. Incubation of rat liver microsomes with 14C-halothane in a nitrogen atmosphere results in a high correlation between the formation of conjugated dienes and the binding of a halothane metabolite to phospholipids. Both the binding and the formation of the conjugated dienes required NADPH, were inhibited by carbon monoxide, and increased with duration of incubation and with protein concentration. Both [36Cl] halothane and [14C] halothane showed a similar pattern of binding to microsomal phospholipids suggesting that the chlorine atom is retained by the metabolite that binds. Neither high levels of conjugated dienes produced by halothane in microsomes incubated under nitrogen nor the binding of the halothane metabolite results in the destruction of cytochrome P-450.


Studies on the mechanism of toxicity and of development of tolerance to the pulmonary toxin, alpha-naphthylthiourea (ANTU). The in vivo administration of the radiolabeled lung toxin alpha-naphthylthiourea (ANTU) to rats leads to the covalent binding of radioactivity to the macromolecules of the lung and liver. In contrast, very little radioactivity is bound in these organs when an equal amount of the 14C-labeled oxygen analog of ANTU, 14C-alpha-naphthylurea (ANU), is administered. In addition, ANU is essentially nontoxic to rats. ANTU is metabolized in vitro by lung and liver microsomes to an intermediate which covalently binds to the macromolecules of the microsomes. This covalent binding, which requires NADPH, leads to a decrease in mixed-function oxidase activity and to a decrease in the level of cytochrome P-450 detectable as its carbon monoxide complex. Incubation of microsomes with ANTU in the absence of NADPH or with ANU in the presence of NADPH, has no effect on these parameters. Pretreatment of rats with small nonlethal doses of ANTU daily for 5 days brings about a decrease in the activity of the mixed-function oxidase enzyme system in the lung which metabolizes parathion. In addition, this pretreatment decreases the toxicity of ANTU and leads to a decrease in the amount of radioactivity bound to the macromolecules of the lung when the animals are given a lethal dose of 35S-ANTU. These data suggest that the lung toxicity of ANTU is brought about by its metabolic activation and covalent binding to lung macromolecules.


Stereospecific binding of timolol, a beta-adrenergic blocking agent. The beta-adrenergic blocking agent, timolol, appears to be bound to stereospecific as well as nonspecific sites in the particulate fraction (8500g pellet) of the heart, lungs, and brain, whereas the d-isomer of timolol was bound to nonspecific sites only. Timolol disappeared from the particulate fraction at a slower rate than did its optical isomer. At 1 hr after a 0.1-mg/kg dose, the concentration of the l-form in the lung was 1.8 times that of the d-isomer and at 3 and 4 hr the difference was at least 33-fold. The concentration of 14C-timolol in the particulate fraction of rat tissues was inhibited by iv administered timolol and by the l-isomer of propanolol, but not by their corresponding d-forms. Competition for binding sites was dose dependent. Pretreatment with timolol at 0.1 and 5.0 mg/kg reduced the binding of 14C-timolol (dose, 0.1 mg/kg) to lung tissue by 41% and 86%, respectively. In the heart and lung tissue of rats, racemic timolol, propranolol, bunolol, and bunitrolol were approximately equally effective in competing for the binding sites of 14C-timolol. Practolol and sotalol and the beta 2-selective agent butoxamine did not significantly inhibit the binding of 14C-timolol. Similar competition was also observed in the whole brain of rats. This report suggests that the stereospecific binding of timolol may be related to the beta-adrenoreceptor process.


Inversion of optical configuration of alpha-methylfluorene-2-acetic acid (cicloprofen) in rats and monkeys. A simple and sensitive radiometric method to determine the individual enantiomers of cicloprofen has been developed. 14C-Cicloprofen was converted to its L-leucine diastereoisomers, which were separated by thin-layer chromatography and quantified by measuring the radioactivity in the area corresponding to each individual diastereoisomer. This technique has also been used to measure the enantiomers of unlabeled cicloprofen by condensing with 14C-labeled L-leucine. By using the radiometric method, a unique biotransformation process, the inversion of the (-)-enantiomer of alpha-methylfluorene-2-acetic acid to its (+)-enantiomer, has been demonstrated in the rat and monkey. The rate of (-)- to (+)-inversion was found to be faster in the rat than in the monkey. After single or repeated oral adminstration of the racemic modification or the (-)-enantiomer of cicloprofen to both species, the ratio of (+)- to (-)-enantiomers of cicloprofen in plasma, urine, or bile increased with time. At 5, 22, and 48 hr after oral administration of a single 50-mg/kg dose of the (-)-enantiomer, 14C-cicloprofen in rat plasma contained 20, 50, and 79%, respectively, of the (+)-enantiomer. After receiving the same dose of (-)-enantiomer, monkey plasma contained 16.5% and 32% of (+)-enantiomer at 8 and 24 hr, respectively. After oral administration of a single 50-mg/kg dose of the (+)-enantiomer of 14C-cicloprofen to rats and monkeys, the percentage of (-)-enantiomer in plasma varied from 2 to 15%. Since the administered (+)-enantiomer contained 4% of (-)-enantiomer and the (+)-enantiomer was excreted at a faster rate than its (-)-antipode by rats or monkeys, it is not known whether an occasional small percentage increase of (-)-enantiomer in plasma resulted from the (+)-to-(-) inversion, or from faster elimination of the (+)-enantiomer. Nevertheless, if (+)-to-(-) inversion does occur in these two species, the rate is much slower than for the (-)-to-(+) inversion.


Buffer catalysis of the racemization reaction of some 5-phenylhydantoins and its relation to the in vivo metabolism of ethotoin. Evidence is presented to show that an optical isomer of 5-phenylhydantoin is subject to racemization (interconversion) in different buffer systems. With phosphate buffers in the pH range of 6.0-7.5, it appears that the buffer-catalyzed racemization reaction is due solely to catalysis by divalent phosphate (general base catalysis). Other buffers studied include arsenate, imidazole, triethanolamine, and pyrophosphate. When 5-phenylhydantoin, the N-de-ethylated metabolite of ethotoin, was administered to dogs in an earlier investigation, the observation was made that somewhat more than the theoretical quantity (50 mole percent of the dose) of the substances recovered from urine had the R-configuration. The principal metabolite was (R)-(-)-2-phenylhydantoic acid, formed stereo-specifically in a ring-opening reaction of (R)-5-phyenylhydantoin by dihydropyrimidinase (EC 3.5.2.2). The results of the present in vitro study support the hypothesis that in vivo the interconversion of the optical isomers of 5-phenylhydantoin can be catalyzed by buffering components of the mammalian physiological system, and that the catalytic activities of the endogenous buffer components can account for the racemization and ultimate metabolism of the (S)-isomer of 5-phenylhydantoin by dihydropyrimidinase.


5,5-Bis(3-hydroxyphenyl)hydantoin, a minor metabolite of diphenylhydantoin (dilantin) in the rat and human. 5,5-Bis(4-hydroxyphenyl) hydantoin has been identified as a minor metabolite of diphenylhydantoin (DPH) in the rat and human. This metabolite was synthesized in the laboratory from 4,4'-dihydroxybenzophenone. Gas chromatographic and mass spectrometric comparison of the permethylated synthetic compound with the permethylated derivative of the metabolite obtained from biological sources showed that they were identical. The metabolite was excreted as a glucuronide and accounted for about 1% of the total hydroxylated metabolites of DPH in human urine and rat bile. When the synthetic standard was added to the recirculating perfusate of the isolated perfused rat liver, a monoglucuronide, a trihydroxy-DPH glucuronide, and a dihydroxymethoxy-DPH glucuronide were identified in the bile.


Metabolism of dihalomethanes to formaldehyde and inorganic halide. I. In vitro studies. Metabolism of dihalomethanes by rat liver cytosol fractions yielded formaldehyde and inorganic halide as products. Loss of metabolic activity resulting from dialysis of the cytosol was restored with glutathione. Cysteine could not substitute for GSH. No other cofactor was found to be required for activity. The optimum conditions for this biotransformation with respect to time, temperature, protein concentration, and pH were determined. Rates of metabolism of dihalomethanes showed the following order: CH2i2 greater than CH2Br2 congruent to CH2BrCi greater than CH2Ci2. Administration of the enzyme inducer, phenobarbital, to rats did not alter this metabolic pathway nor did repeated administration of CH2Br2 or CH2Ci2 change the rate of metabolism. The enzyme catalyzing this reaction was localized in the liver. Compounds known to serve as substrates for various GSH transferases inhibited the reaction as did those capable of interacting with sulfhydryl groups.


Metabolism of 2,4,5,2',5'-pentachlorobiphenyl in the rat. Qualitative and quantitative aspects. The metabolism of 2,4,5,2',5'-pentachloro [14C] biphenyl (5-CB) was studied in the male rat. Following iv administration of 5-CB (0.6 mg/kg), 84% of the total dose was excreted within 7 days and 89% of the radioactivity excreted was in the form of 5-CB metabolites. Mass spectral and proton nuclear magnetic resonance analysis or chemical methods in conjunction with mass spectral analysis were used to identify the metabolites. The major metabolite was identified as 3'-hydroxy 5-CB. One minor metabolite was identified as the 3',4'-dihydrodiol of 5-CB and a second minor metabolite was tentatively identified as 3',4'-dihydroxy-5-CB. The relative amounts of 5-CB and its metabolites excreted in the urine and feces were also determined.


3-(Hydroxymethyl)-8-methoxychromone and unconjugated metabolites in rat plasma. Identification of the biologically active species. After administering 14C-labeled 3-(hydroxymethyl)-8-methoxychromone to rats by gavage, plasma was found to contain unchanged compound and three unconjugated metabolites. These metabolites were identified as 3-carboxy-8-methoxychromone, 8-methoxychromone, and 2-hydroxy-3-methoxyactophenone. The plasma levels of all four labeled compounds were determined from 30 min to 48 hr after drug administration. Only the levels of 3-(hydroxymethyl)-8-methoxychromone and 3-carboxy-8-methoxychromone correlated with the expression of antiallergy activity in the rat, and only these compounds were found to be active in vivo. However, a test system for the inhibition of anaphylactic histamine release in vitro showed activity only for 3-carboxy-8-methoxychromone.


Metabolism of tripelennamine in man.

Metabolism of tripelennamine in man. Four polar metabolites were isolated from the urine of human subjects orally treated with tripelennamine, and their structures elucidated by various chemical and physical methods. One of the metabolites, which is a minor one, was identified as an N-oxide of tripelennamine, and the other three as glucuronide conjugates. One of the conjugates, which is a major metabolite, has been assigned a unique quaternary ammonium N-glucuronide structure, since it gave tripelennamine and D-glucuronic acid on incubation with beta-glucuronidase. The N-oxide, which has also been prepared synthetically, remained unchanged on similar treatment. The other two conjugates were O-glucuronides of hydroxylated derivatives, the glucuronide of hydroxytripelennamine being the principal metabolite. No desmethyltripelennamine was found in the urine, however. Hydroxylation in both cases had occurred in the pyridine ring.


Disposition and metabolism of 3-(3-chlorophenoxy)-N-methylpyrrolidine [14C]-carboxamide in the rat, dog, and man. Studies with a 14C-labeled sample have shown that the title compound A is readily absorbed and very rapidly excreted by the rat, dog, and man. The metabolites result from aromatic ring hydroxylation, oxidation, and dealkylation of the urea methyl group, and oxidative ring opening of the pyrrolidine ring. Rat metabolites were 3-(3-chloro-4-hydroxyphenoxy)-N-methyl-l-pyrrolidinecarboxamide (C) 3-(3-chloro-4-hydroxyphenoxy)-1-pyrrolidinecarboxamide (D), 3-(3-chlorohydroxyphenoxy)-1-pyrrolidinecarboxamide (E), 3-(3-chlorophenoxy)-4([(methylamino)-carbonyl]amino)butanoic acid (G), 3-(3-chlorophenoxy)-4[(aminocarbonyl)amino]butanoic acid (H). Dog metabolites were C, D, G, and H. Human metabolites were 3-(3-chloro-4-hydroxyphenoxy)-N-formyl-l-pyrrolidinecarboxamide (F), C, D, G, and H. An electron-capture gas chromatographic assay for the parent compound is described. Whole-body autoradiograms of rat slices and the tissue residue data from these slices are reported and indicate rapid tissue depletion of radioactivity.