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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expired ethanol and acetaldehyde were measured after an oral injection of ethanol in C57BL/6J and DBA/2J mouse strains by a combination of several techniques in a sequence involving a method for trapping expired radioactive compounds, separation of compounds by gas chromatography, isolation of radioactive ethanol and acetaldehyde, and their quantitative analysis by liquid scintillation spectrophotometry. With the specific activities used in evaluation of the technique (0.1 Ci/mole, acetaldehyde; 1.1 Ci/mol, ethanol) the lower limit of sensitivity using 500 microliters from a 10 ml trap is 955 pmoles for acetaldehyde and 101 pmoles for ethanol. However, in the animal experiments, injected ethanol has a specific activity of 1.1 Ci/mol which would make the specific activity of expired metabolically formed acetaldehyde the same. This results in a lower limit of sensitivity for acetaldehyde of 80 pmoles. The two strains were monitored for 80 min following an oral injection of 3.8 g/Kg of (2-14C) ethanol. Comparing the two strains on the expiration of each compound the curves were identical.
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PMID:A quantitative analysis of ethanol and acetaldehyde expired by inbred mouse strains. 739 48

Experiments with one and two steps blanching of green beans have been carried out. Inactivation of the peroxydase requires more heating than inactivation of the enzymes which gives rise to off flavour from aldehydes. When blanching for about one minute to inactivate lipoxygenase, aldehyde formation of flavour ceases. The content of vitamin C decreases during blanching according to a first order reaction. Since considerable loss of vitamin C occurs during blanching, the treatment time should be reduced to a minimum. During preblanching at 65-75 degrees C and final blanching, chlorophyll is degraded to pheophytin and the surface colour expressed by the Hunter-values (-a/b) increases with time which means that the colour of the beans changes from green to yellow. The firmness of beans, which was measured by use of a tenderometer, decreases during blanching according to a first order reaction with 40 kcal/mole activation energy. Preblanching at 65-75 degrees C increases the firmness of the beans linearly with treatment time. This increase in firmness is stable after final blanching at 95 degrees C and even after thawing of frozen beans.
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PMID:Blanching of green bean (Phaseolus vulgaris). 771 18

We have researched the influence of ionol, dimethylsulfoxide and distinol preparation with different mole correlation of ingredients on the intensity of formation of malonic aldehyde and the activity of antioxidant enzymes in chickens' tissues. Results showed that distinol preparation with mole correlation of ionol and dimethylsulfoxide 1:2 parallel with anti-radical and antioxidant action, increased the activity of antioxidant enzymes in chickens' organs, exerting great indirect antioxidative effect.
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PMID:[Effect of ionol and dimethylsulfoxide on activity of enzymes of the antioxidant system in chickens]. 774 41

Sphingosine-1-phosphate (Sph-1-P) is the initial product of catabolism of sphingosine by sphingosine kinase and is cleaved by Sph-1-P lyase to a fatty aldehyde and ethanolamine phosphate. This phosphorylated sphingoid base is not only an intermediary catabolite, but also a bioactive lipid with important functions, including stimulation of cell proliferation in Swiss 3T3 fibroblasts and inhibition of tumor cell motility. In the present study, we examined functional roles of Sph-1-P in human platelets. Sph-1-P induced platelet shape change and aggregation reactions, although it failed to elicit secretion. Sphingosine, ceramide, sphingomyelin, and N,N-dimethylsphingosine did not mimic the positive effects of Sph-1-P on platelets. Subthreshold concentrations of Sph-1-P and weak platelet agonists such as adenosine diphosphate (ADP) and epinephrine synergistically elicited aggregation, which may be important for efficient amplification of platelet activation. Sph-1-P induced intracellular Ca2+ mobilization and the dose-response for Ca2+ release correlated closely with the concentration required for induction of shape change. On addition of [3H]sphingosine to intact platelets, the label was rapidly converted to Sph-1-P, and subsequently to ceramide and sphingomyelin. Interestingly, the Sph-1-P formed was specifically released into medium on stimulation of platelets with physiologic agonists. The amount of Sph-1-P in platelets, as measured by its conversion into radiolabeled N-acetyl-Sph-1-P, was 1.4 nmol/10(9) cells and was about four times higher than the mass of Sph present. When compared by mole percent Sph-1-P/phospholipid, the value for platelets is over 10 times higher than that for neutrophils. Our results suggest that Sph-1-P, rapidly converted from sphingosine, abundantly stored in platelets, and released on the cell activation, may play a physiologic role in thrombosis, hemostasis, and the natural wound-healing processes.
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PMID:Sphingosine-1-phosphate: a platelet-activating sphingolipid released from agonist-stimulated human platelets. 779 24

Immunostaining with the monoclonal antibodies PCNA and Ki-67 provides a simple method for the assessment of growth fractions of tumors. Contrary to Ki-67, PCNA antibody can be applied on aldehyde- or alcohol-fixed and paraffin-embedded tissues, thus allowing studies on archival material. For 77 melanocytic skin lesions, we compared PCNA immunostaining on formalin-fixed tissue with Ki-67 immunostaining on frozen material of the same lesion. 16 benign melanocytic nevi (BMN, from 16 patients), 43 primary malignant melanomas (PMM, 42 patients), and 18 skin metastases of malignant melanoma (MMM, 12 patients) were included in the study. Maximum nuclear density (NDmax) of PCNA- and Ki-67-positive nuclei was assessed using interactive image analysis. NDmax values for both PCNA and Ki-67 differed significantly between the three diagnostic groups (Kruskal-Wallis H-test: p << 0.001). Mean values (given as 1000 nuclei/mm3 tissue) increased considerably from benign to malignant lesions (PCNA: BMN: 23.8 +/- 28.4 [mean +/- standard deviation], PMM: 48.1 +/- 41.0, MMM: 117.0 +/- 64.6; Ki-67: BMN: 6.4 +/- 3.3, PMM 25.0 +/- 31.1, MMM: 95.2 +/- 47.2). Correlation between NDmax values of PCNA- and Ki-67-positive nuclei was significant (Linear regression analysis: r = 0.51, p << 0.001). Furthermore, for PMM a significant correlation between histologic parameters related to prognosis (Breslow index and mitotic rate) and PCNA as well as Ki-67 expression was found (PCNA-Breslow index: r = 0.42, p < 0.01; Ki-67-Breslow index: r = 0.60, p << 0.001; PCNA-mitotic rate: r = 0.40, p < 0.01; Ki-67-mitotic rate: r = 0.50, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of proliferative activity as assessed by proliferating cell nuclear antigen (PCNA) and Ki-67 monoclonal antibodies in melanocytic skin lesions. A quantitative immunohistochemical study. 810 31

Using cross-linking stereochemistry as indicators, the molecular environment of two collagens in the turkey leg Achilles tendon were compared. The tendon from one year old turkeys was dissected into nonmineralized, fully mineralized and transitionally mineralized portions. Amino acid composition and cyanogen bromide peptide mapping of these portions indicated that the collagens were essentially type I throughout. The fully mineralized compartment had a lysine hydroxylation level similar to turkey or mammalian bone collagen. The non- and transitionally mineralized collagens had a significantly higher lysine hydroxylation, typical of tendon or ligament. However, unlike mammalian tendon, the collagen cross-links were essentially derived from the carboxy-terminal ends of the molecules. The predominant cross-link in this portion was pyridinoline having a high content of 0.95 +/- 0.09 res/mole of collagen. The cross-links in the fully mineralized collagen were also essentially derived from carboxy-terminal aldehyde. However, here significant amounts of the lysyl analog of pyridinoline and lysine-involved bifunctional cross-links were present. The molecular loci of pyridinoline in nonmineralized collagen and the lysyl analog of pyridinoline in mineralized collagen were found to be identical. The total trifunctional cross-link level in the mineralized collagen, 0.55 +/- 0.05 res/mole of collagen, was virtually identical to that observed in old mammalian bone and dentin, and in long term in vitro incubation studies of predentin. We have tentatively concluded that the post-translational chemistry and molecular environments are different in these two turkey tendon fibrils. However, a relative paucity of amino-terminal based cross-links is a feature they have in common. The possible involvement of the amino-terminal telopeptides in collagen mineralization is discussed.
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PMID:The post-translational chemistry and molecular packing of mineralizing tendon collagens. 840 98

Ovine longissimus dorsi and biceps femoris muscles were analyzed for proteoglycan content, collagen and lysine aldehyde-derived collagen crosslinking concentrations at 2-4 days, six-month-old, and six-year-old stages of development. Tissue extracted proteoglycan molecular sieve distribution on a Sephacryl S-200HR column revealed two proteoglycan populations with estimated relative molecular weight ranges of 200,000 to 250,000 daltons and 23,000 to 70,000 daltons. The molecular sieve distribution was similar between the two muscles within a developmental age, but changed as a function of developmental age. Primary culture from both the longissimus dorsi and biceps femoris muscle liberated proteoglycans into the culture medium. In contrast to the tissue extracted proteoglycans, at the six-year-old stage of development, culture medium liberated proteoglycan Sephacryl S-200HR molecular sieve distribution differed between the two muscles. In both the tissue extracted and medium liberated proteoglycans at all developmental stages, nitrous acid deamination demonstrated the presence of heparan sulfate. Immunoblot analysis of the tissue extracted proteoglycans indicated the presence of decorin at each developmental stage. Longissimus dorsi and biceps femoris collagen concentrations (5.13 +/- 0.9 vs. 5.53 +/- 1.5%, respectively) and crosslink concentrations (0.07 +/- 0.01 moles HP/mole collagen) were initially similar between the two muscles; however, by six-months the muscles differed in both collagen concentration (1.72 +/- 0.5 and 2.53 +/- 0.7%, respectively) and crosslinking (0.24 +/- 0.02 and 0.27 +/- 0.03 moles HP/mole collagen, respectively). At six years of age, both the longissimus dorsi and biceps femoris exhibited slightly elevated collagen concentrations (2.49 and 3.05%, respectively) while crosslinking values were decreased relative to values at six-months of age (0.11 +/- 0.01 and 0.18 +/- 0.01 moles HP/mole of collagen, respectively). The results from this study indicate that skeletal muscle proteoglycans and collagen show developmental changes, which suggests that they are subject to developmental regulation.
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PMID:Partial characterization of ovine skeletal muscle proteoglycans and collagen. 902 47

Isoflavonoid derivatives including prunetin (4',5-dihydroxy-7-methoxyisoflavone) were shown to be potent inhibitors of human aldehyde dehydrogenases (Keung W-M and Vallee BL, Proc Natl Acad Sci USA 90: 1247-1251, 1993). The inhibition reaction was reinvestigated using recombinantly expressed human aldehyde dehydrogenases. The kinetic analyses showed that prunetin inhibits competitively against both NAD and propionaldehyde with the mitochondrial and cytoplasmic enzymes. The Ki value for the mitochondrial enzyme was much lower than for the cytoplasmicenzyme. A mixed pattern of inhibition was obtaiend with the mitochondrial enzyme in the presence of Mg2+. Only one mole of prunetin binds per mole of tetrameric mitochondrial enzyme, which remains unaltered in the presence of Mg2+. Prunetin did not displace NADH from the enzyme-NADH complex. Propionaldehyde did not reverse the loss of fluorescence obtained due to enzyme-prunetin complex formation, indicating that prunetin may not be interacting at the substrate site. The esterase activity of the mitochondrial enzyme was also inhibited by prunetin in a competitive manner. The replacement of lysine 192 by glutamine resulted in a mutant with a 20% kcat and a 100-fold increase in the Km for NAI) compared with the native enzyme. However, the Ki value of prunetin against NAD was similar to that observed with the native enzyme. Prunetin, even at a very high concentration, was not an inhibitor of alcohol and malate dehydrogenase. It was concluded that prunetin may act as an allosteric inhibitor of aldehyde dehydrogenase.
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PMID:Allosteric inhibition of human liver aldehyde dehydrogenase by the isoflavone prunetin. 910 97

Lignin peroxidases (LiP) from the white-rot fungus Phanerochaete chrysosporium oxidize veratryl alcohol (VA) by two electrons to veratryl aldehyde, although the VA cation radical (VA.+) is an intermediate [Khindaria, A., et al. (1995) Biochemistry 34, 6020-6025]. It was speculated, on the basis of kinetic evidence, that VA*+ can form a catalytic complex with LiP compound II. We have used low-temperature EPR to provide direct evidence for the formation of the complex. The EPR spectrum of VA*+ obtained at 4 K was explained by a model for coupling between the oxoferryl moiety of the heme (S = 1) and VA.+ (S = 1/2) similar to the model proposed for an oxyferryl and a porphyrin pi cation radical of horseradish peroxidase. The coupling constant suggested that VA.+ was equally ferro- and antiferromagnetically coupled to the oxoferryl moiety. The spectrum was simulated with g perpendicular only marginally greater than g parallel. This was surprising since the only other known organic radical coupled to the heme iron in a peroxidase is the tryptophan cation radical in cytochrome c peroxidase which exhibits a g tensor with g parallel greater than g perpendicular. Spin concentration analysis suggested that the 1 mol of VA*+ was coupled to the oxoferryl moiety per mole of enzyme. The VA.+ signal decayed with a first-order decay constant of 1.76 s-1, in close agreement with the earlier published decay constant of 1.85 s-1 from room-temperature EPR studies. The exchange coupling between VA.+ and the oxoferryl moiety strongly advocates calling this species (VA.+ and LiP compound II) a catalytic complex.
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PMID:Detection and characterization of the lignin peroxidase compound II-veratryl alcohol cation radical complex. 936 91

Keloid is a tissue with an excessive accumulation of collagen. In this study, we have partially characterized post-translational modifications of type I collagen in human keloid in order to pursue their potential involvement in this pathology. The levels of lysyl hydroxylation of the helical portions of alpha 1 and alpha 2 chains of type I collagen in keloid were significantly higher than those of normal, while the levels of prolyl hydroxylation were identical between these two groups. The contents of the major reducible cross-links in dermal collagen, dehydro-hydroxylysinonorleucine and dehydro-histidinohydroxymero-desmosine, were both significantly higher in keloids (up to sixfold) than those of normal. In addition, significant amounts of hydroxylysine-aldehyde derived cross-links that are characteristic of skeletal tissue collagens, dehydro-dihydroxylysinonorleucine (about 0.3 mole/mole of collagen) and pyridinoline (about 0.1 mole/mole of collagen), were found in keloids. These results indicate that keloid-forming cells are phenotypically different from those in normal dermis and that the collagen produced is highly cross-linked. The increased cross-linking provides the fibrils with more stability that may result in an accumulation of collagen.
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PMID:Altered posttranslational modifications of collagen in keloid. 973 Nov 91


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