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M T Ryzlak

Publications and source records attributed to M T Ryzlak.

14 recordsLinked to original sources
PubMed1993

Comparative neurotoxicities of amphotericin B and its mono-methyl ester derivative in rats.

The intracisternal administration of amphotericin B (AmB) and its mono-methyl ester derivative (AME), via direct intraventricular injection (0.01 to 5 mg/ml, 6 microliters) in adult female Wistar rats, revealed that AmB was significantly more toxic than AME, as measured by weight loss, lethargy, death, and central nervous system histopathology. Light and electron microscopy confirmed a greater neurotoxicity for AmB, manifested as edema and modest gliosis extending along and beyond the injection tract. Neuronal degeneration and myelin damage were present in AmB-treated (1 mg/ml) animals but were present only modestly in animals treated with AME at a fivefold greater concentration. Intravenous administration of AmB to adult female Wistar rats as five daily doses of 5 mg/kg of body weight resulted in significant weight loss and some deaths. Histopathologic examination of the brains, spinal cords, and sural nerves of surviving animals revealed neurotoxicity manifested by neuronal degeneration, gliosis, and myelin edema. In sharp contrast, similar treatment with AME at a 10-fold greater dose resulted in neither death nor significant neurotoxicity. The administration of five daily doses of a mixture of AME-AmB (9:1; wt/wt) at 50 mg/kg of body weight resulted in neurotoxicity. These results indicate that AmB exhibits significantly greater in vivo neurotoxicity than AME.

Amphotericin B↗
PubMed1992

Human prostatic aldehyde dehydrogenase of healthy controls and diseased prostates.

Aldehyde dehydrogenase (ALDH, EC 1.2.1.3) of the human prostate was the subject of investigation in this study. The possible physiological role of aldehyde dehydrogenase in the human prostate might be to detoxify aldehydes arising from the oxidation of the polyamines via monoamine or diamine oxidases. The specific activity of the enzyme with 1 mM propionaldehyde as substrate and 0.5 mM NAD at pH 7.4 in the control normal prostates and prostates afflicted with the disease, benign prostatic hyperplasia (BPH), was 26.06 +/- 2.96 and 5.17 +/- 0.48 nmol/g prostate per min, respectively. When 100 microM gamma-aminobutyraldehyde was used as a substrate, the specific activity in the normal controls and prostates with benign prostatic hyperplasia was 19.80 +/- 1.33 and 2.95 +/- 2.46 nmol/g prostate per min, respectively. Upon isoelectric focusing of the extracts of the control prostates when the gels were developed for aldehyde dehydrogenase activity, there were three aldehyde dehydrogenase activity bands visible, pI 4.9 (mitochondrial), 5.4 (cytosolic) and about 6.0-6.5, on the IEF gels developed with gamma-aminobutyraldehyde as a substrate. With the extracts of prostates with benign prostatic hyperplasia the pI 4.9 band was significantly reduced, the pI 5.4 band enhanced and the approx. pI 6.0 band was not detectable on the IEF gels with propionaldehyde as a substrate. There was no detectable aldehyde dehydrogenase activity in the extract of the prostate with cancer on IEF gels nor in the activity assays with propionaldehyde or gamma-aminobutyraldehyde as substrates.

Aged↗
PubMed1991

Effect of cholesta-3,5-dien-7-one on human liver aldehyde dehydrogenase.

A recently isolated cholesterol oxidation product, cholesta-3,5-dien-7-one, which was present at high concentrations in fatty/cirrhotic alcoholic liver was identified as a potent endogenous inhibitor of the cytosolic, E1, isozyme of aldehyde dehydrogenase (EC 1.2.1.3). The oxysterol was a less potent inhibitor of mitochondrial, E2, isozyme. The inhibition of the E1 isozyme was irreversible on the IEF gels, upon dilution and with 33 microM 2-mercaptoethanol during activity assay. The calculated 1-50% values from the inhibition curves for the E1 isozyme were 5-10 microM and approx. 180 microM for the E2 isozyme. The E3 isozyme was not sensitive to the oxysterol. Judging from the Lineweaver-Burk plot, the inhibition of the E1 isozyme with a constant concentration of cholesta-3,5-dien-7-one (52 microM) appeared to be noncompetitive.

Adolescent↗
PubMed1990

Oxysterols and alcoholic liver disease.

A new theory is presented implicating oxidative cholesterol metabolism and oxysterols as possible factors in the development of alcoholic liver disease. Our present studies have revealed the accumulation of cholesta-3,5-dien-7-one, 13.05 +/- 2.75 micrograms/g (n = 8), and cholesta-4,6-dien-3-one, 2.26 +/- 0.88 micrograms/g (n = 8) in fatty alcoholic liver, as compared with controls, 0.21 +/- 0.12 microgram/g (n = 7) and 0.3 +/- 0.33 microgram/g (n = 7), respectively. Acetaldehyde at 1 to 6 micromolar concentration in the blood and tissues of alcoholics cannot account for the extent of tissue damage, nor can it adequately explain liver steatosis characterized by accumulation of cholesterol and fatty acids and their esters in the liver of alcoholics known for their poor dietary habits. Oxysterols may be the primary cause for the development of alcoholic liver diseases and damage to accessory tissues. Significantly lower levels of 7-ketocholesterol in fatty liver, 6.8 +/- 3.5 micrograms/g (n = 8), as compared with control, 36.85 +/- 22.25 micrograms/g (n = 7), may be responsible for the increased cholesterol content of the alcoholic liver due to the inhibitory properties of this sterol on HMG-CoA reductase in cholesterol biosynthesis.

Cholesterol↗
PubMed1989

Human brain glyceraldehyde-3-phosphate dehydrogenase, succinic semialdehyde dehydrogenase and aldehyde dehydrogenase isozymes: substrate specificity and sensitivity to disulfiram.

Several enzymes active in the presence of NAD with acetaldehyde and propionaldehyde have been purified from human brain and characterized. The enzymes have been identified as aldehyde dehydrogenase (EC 1.2.1.3), NAD-linked succinic semialdehyde dehydrogenase (EC 1.2.1.24), and glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12). Glyceraldehyde-3-phosphate dehydrogenase is extremely heterogeneous with some isozymes active with acetaldehyde, others inactive. The cytoplasmic enzyme, which is the classical glyceraldehyde-3-phosphate dehydrogenase, is inactive with acetaldehyde as substrate; the isozymes that are active with short chain aliphatic aldehydes are localized in the mitochondrial fraction. Properties of glyceraldehyde-3-phosphate dehydrogenase isozymes with respect to short chain aliphatic aldehydes and inhibition by disulfiram are described. Their Km values for acetaldehyde range from 300 to 2000 microM. All glyceraldehyde-3-phosphate dehydrogenases that are active with acetaldehyde are easily inactivated by low concentrations of disulfiram. In all cases activity regain can be obtained with 2-mercaptoethanol; in the case of two glyceraldehyde-3-phosphate isozymes (E8.5 and 9.0), activity can also be regained with cysteine and with glutathione; activity of E6.6 and E6.8 glyceraldehyde-3-phosphate dehydrogenases could not be regained with 33 microM cysteine or glutathione. Succinic semialdehyde dehydrogenase and aldehyde dehydrogenase (EC 1.2.1.3) were also inhibited by disulfiram; their activity could be regained with 2-mercaptoethanol but not with 33 microM cysteine or glutathione. Comparison of human brain succinic semialdehyde dehydrogenase and aldehyde dehydrogenase with glyceraldehyde-3-phosphate dehydrogenase shows that the activity with short chain aldehydes is not unique to aldehyde dehydrogenase; neither is sensitivity to disulfiram; activity with 3,4-dihydroxyphenylacetaldehyde appears to be a unique property of aldehyde dehydrogenase (EC 1.2.1.3).

Aldehyde Dehydrogenase↗
PubMed1988

Human brain "high Km" aldehyde dehydrogenase: purification, characterization, and identification as NAD+ -dependent succinic semialdehyde dehydrogenase.

NAD-dependent succinic semialdehyde dehydrogenase (EC 1.2.1.24) has been purified to homogeneity from human brain via ion-exchange chromatography and affinity chromatography employing Blue Sepharose and 5'-AMP Sepharose. Succinic semialdehyde dehydrogenase was never previously purified to homogeneity from any species; this preparation therefore allows the determination of its molecular weight, subunit molecular weight, subunit composition, isoelectric points, and substrate specificity for the first time. The enzyme is a tetramer of Mr230,000 to 245,000 and consists of weight-nonidentical subunits (Mr 61,000 and 63,000). On isoelectric focusing the enzyme separates into five bands with the following isoelectric points: 6.3, 6.6, 6.8, 6.95, and 7.15. Its substrates include glutaric semialdehyde, nitrobenzaldehyde, and short chain aliphatic aldehydes in addition to succinic semialdehyde which is the best substrate. The Km values for succinic semialdehyde, acetaldehyde, and propionaldehyde are 1,875, and 580 microM, respectively. The enzyme is inactive with 3,4-dihydroxyphenylacetaldehyde and indole-3-acetaldehyde as substrates. Its subcellular localization is in the mitochondrial fraction. Succinic semialdehyde dehydrogenase is sensitive to inhibition by disulfiram (a drug used therapeutically to produce alcohol aversion) resembling, in this respect, aldehyde dehydrogenase (EC 1.2.1.3). It does not, however, interact with the antibody developed in the rabbit vs aldehyde dehydrogenase, suggesting that the two enzymes are structurally distinct.

Aldehyde Dehydrogenase↗
PubMed1988

Heterogeneity of glyceraldehyde-3-phosphate dehydrogenase from human brain.

In an attempt to characterize enzymes from human brain capable of dehydrogenating short chain aliphatic aldehydes, four groups of enzymes which catalyze inorganic phosphate-dependent reversible dehydrogenation of glyceraldehyde 3-phosphate as well as short chain aldehydes have been purified and characterized. Three enzyme groups are visualized as multiple bands on isoelectric focusing: E6.6 (pI 6.65, 6.75, 6.85); E6.8 (pI 6.8, 6.9); E8.5 (pI 8.5, 8.6); one enzyme, E9.0, is seen as a single band pI 9.0. The subcellular localization of E6.8, E8.5 and E9.0 appears to be mitochondrial. The mitochondrial enzymes differ slightly in molecular weight: E6.8 is 142,000 with subunits of 36,000 and 38,000; E8.5 is 120,000 with a subunit weight of 29,500; E9.0 is 133,000 with a subunit of 33,000. The E8.5 and E9.0 enzymes also appear to contain Zr as part of their molecular structure. E6.6 (subcellular localization uncertain) is a dimer with a molecular weight of 98,000 and two subunits of 58,000 and 61,000. The specific activity with glyceraldehyde-3-phosphate is: E6.6, 8.6 IU/mg; E6.8, 13 IU/mg; E8.5, 158 IU/mg; E9.0, 620 IU/mg. With glyceraldehyde 3-phosphate and 1,3-diphosphoglyceric acid and Km values of all the enzymes are similar (10-40 microM), except for E6.8 whose Km for glyceraldehyde 3-phosphate is very sensitive to pH and is extremely low at pH 7.0 (2 microM), while being considerably higher than that for the other enzymes at pH 9.0 (170 microM). The molecular properties, Km values as well as high specific activity with glyceraldehyde 3-phosphate identify E6.8, E8.5 and E9.0 as glyceraldehyde-3-phosphate dehydrogenases (EC 1.2.1.12). The catalytic properties of E6.6 are similar to those of E6.8, E8.5 and E9.0, but its molecular properties are different, precluding definite identification.

Aldehydes↗
PubMed1987

Purification and characterization of aldehyde dehydrogenase from human brain.

Aldehyde dehydrogenase (EC 1.2.1.3) has been purified from human brain; this constitutes the first purification to homogeneity from the brain of any mammalian species. Of the three isozymes purified two are mitochondrial in origin (Peak I and Peak II) and one is cytoplasmic (Peak III). By comparison of properties, the cytoplasmic Peak III enzyme could be identified as the same as the liver cytoplasmic E1 isozyme (N.J. Greenfield and R. Pietruszko (1977) Biochim. Biophys. Acta 483, 35-45). The Peak I and Peak II enzymes resemble the liver mitochondrial E2 isozyme, but both have properties that differ from those of the liver enzyme. The Peak I enzyme is extremely sensitive to disulfiram while the Peak II enzyme is totally insensitive; liver mitochondrial E2 isozyme is partially sensitive to disulfiram. The specific activity is 0.3 mumol/mg/min for the Peak I and 3.0 mumol/mg/min for the Peak II enzyme; the specific activity of the liver mitochondrial E2 isozyme is 1.6 mumol/min/mg under the same conditions. The Peak I enzyme is also inhibited by acetaldehyde at low concentrations, while the Peak II enzyme and the liver mitochondrial E2 isozyme are not inhibited under the same conditions. The precise relationship of brain Peak I and II enzymes to the liver E2 isozyme is not clear but it cannot be excluded at the present time that the two brain mitochondrial enzymes are brain specific.

Aldehyde Dehydrogenase↗
PubMed1987

Multiplicity and identity of human aldehyde dehydrogenases.

Human "high Km" aldehyde dehydrogenases have been purified to homogeneity and characterized. The "high Km" enzymes are structurally and catalytically distinct from "low Km" aldehyde dehydrogenases; they are not isozymes of the "low Km" enzymes.

1-Pyrroline-5-Carboxylate Dehydrogenase↗
PubMed1976

Endonucleases and simian virus 40 virions: origin of a virion-associated endonuclease.

The origin and role of the endonuclease activity associated with purified virions of simian virus 40, previously described by this and other laboratories, have been further investigated. We found that the enzymatic activity from virions of temperature-sensitive (ts) mutants is not more heat labile than that from wild-type virions. This result was obtained for a variety of ts mutants, including three of the tsA class, and in experiments in which the enzyme was tested in both the presence and absence of viral particles. Comparison of the viron enzyme with endonucleases prepared from either serum or nuclei of uninfected cells reveals a similarity between the viron and serum enzymes based on chromatographic behavior and relative activity with different cations. Virus particles prepared free of this endonuclease were still infectious. We were unsuccessful in uncovering endonuclease in such preparations upon disruption. These data emphasize the necessity for caution in interpreting the role of particle-associated enzymes.

Animals↗