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At least 847 records · Page 47Linked to original sources
PubMed1999

Hepatocyte-specific distribution of catalase and its inhibitory effect on hepatic ischemia/reperfusion injury in mice.

To explore the possibility of using catalase for the treatment of reactive oxygen species (ROS)-mediated injuries, the pharmacokinetics of bovine liver catalase (CAT) labeled with 111In was investigated in mice. At a dose of 0.1 mg/kg, more than 70% of 111In-CAT was recovered in the liver within 10 min after intravenous injection. In addition, 111In-CAT was predominantly recovered from the parenchymal cells (PC) in the liver. Increasing the dose retarded the hepatic uptake of 111In-CAT, suggesting saturation of the uptake process. This cell-specific uptake could not be inhibited by coadministration of various compounds which are known to be taken up by liver PC, indicating that the uptake mechanism of CAT by PC is very specific to this compound. The preventive effect of CAT on a hepatic ischemia/reperfusion injury was examined in mice by measuring the GOT and GPT levels in plasma. A bolus injection of CAT at 5 min prior to the reperfusion attenuated the increase in the levels of these indicators in a dose-dependent manner. These results suggest that catalase can be used for various hepatic injuries caused by ROS.

Alanine Transaminase↗
PubMed2006

An amperometric biosensor for uric acid determination prepared from uricase immobilized in polypyrrole film.

In order to prepare a biosensor for the determination of uric acid, electropolymerization of pyrrole on Pt surface was carried out with an electrochemical cell containing pyrrole, ferrocene (as a electron mediator) and tetrabutylammonium tetrafluoroborat in acetonitrile by cyclic voltammetry between 0.0 and 1.0 V (vs. Ag/AgCl) at a scan rate of 50 mV/s upon Pt electrode. Uricase was immobilized by a glutaraldehyde/gelatine croslinking procedure on to polypyrrole film after the electropolymerization processes. The response of the biosensor against uric acid was measured after 330 seconds following the application of a constant potential of +0.7 V (vs. Ag/AgCl). The resulting biosensor exhibits excellent electrocatalysis for the uric acid. The amperometric determination is based on the electrochemical detection of H2O2, which is generated in enzymatic reaction of uric acid. The sensor responds to uric acid with a detection limit of 5.0 x 10(-7) M. The sensor remains relatively stable for 5 weeks. Interference effect were investigated on the amperometric response of the biosensor. Determination of uric acid was carried out in the biological fluids by biosensor.

Acetaminophen↗
PubMed1966

Studies of lung metabolism. I. Isolation and properties of subcellular fractions from rabbit lung.

The isolation and partial characterization of subcellular particles from rabbit and rat lung are described. Detailed methods for separating a purified, active mitochondrial fraction are outlined and evaluated in terms of enzymatic, chemical, and morphological criteria. Mitochondrial preparations from rabbit and rat liver were used as comparative indices. The lung mitochondrial fraction was identified by its ability to oxidize succinate with a P/O ratio of 1.7 by a process sensitive to 2,4 dinitrophenol and antimycin A. The adenosine triphosphatase activity of the lung mitochondrial fraction is stimulated by magnesium ions, but this stimulation is not augmented by 2,4 dinitrophenol. In the absence of magnesium ions, the specific activity of the adenosine triphosphatase increases with increasing protein concentration. The presence of lysosomes in the mitochondrial fraction is suggested by acid phosphatase and cathepsin activities and by electron microscope observations.

Acid Phosphatase↗
PubMed1968

Electron microscopic and biochemical characteristics of nuclei and nucleoli isolated from rat liver.

Rat liver nuclei were freed of cytoplasmic contamination by washing with Triton-X-100 and subsequent centrifugation through 2.2 M sucrose. Electron microscopic examination showed that the outer membranes of the nuclei had been removed, but that the nuclei otherwise resembled the nuclei of intact liver. Morphological studies, chemical estimations of DNA, RNA, and protein and the estimation of cytoplasmic "marker" enzymes suggested that contamination of nuclei by cytoplasmic components was limited. These nuclei were obtained in yields of about 70% and were suitable for the isolation of nucleoli. Nucleoli were isolated by the breaking of the nuclei by ultrasound and subsequent differential centrifugation. In ultrastructural appearance, the isolated nucleoli resembled nucleoli in intact tissue. However, at high magnifications the "granular" component of isolated nucleoli appeared to consist of tightly twisted fibers. The nucleoli could be obtained in yields of at least 30%, and the values for the chemical composition of the isolated nucleoli agreed with values previously reported.

Acid Phosphatase↗
PubMed1972

Peroxisomes in absorptive cells of mammalian small intestine.

Huge numbers of peroxisomes are present in guinea pig duodenum, jejunum, and ileum, and in rat duodenum. The peroxisomes have been studied by light and electron microscopy, including visualization by incubation in a newly-developed alkaline 3,3' diaminobenzidine (DAB) medium. Electron micrographs of more than 3700 guinea pig peroxisomes have been studied. The diameter of most peroxisomes ranges from 0.15 micro. to 0.25 micro. They often appear in clusters, surrounded by and continuous, in numerous places, with smooth endoplasmic reticulum (ER). The ER is extremely tortuous in these regions. Serial sectioning is valuable for studying the ER-peroxisome relationships but viewing sections at different angles, tilted with a goniometer stage, is more informative. The intimate relations of the two organelles appear the same in tissue fixed in four different fixatives. The peroxisomes may be interpreted as localized dilatations of smooth ER retaining multiple membranous continuities. This interpretation is discussed in light of the turnover data on peroxisomal proteins of rat hepatocytes reported by Poole and colleagues. The very large numbers of peroxisomes in intestinal epithelium lead to speculations concerning their functional significance. They resemble the small peroxisomes described in many other cell types. Although the distinctive relationship of these peroxisomes to the ER is probably more significant than their small size, for practical purposes we propose the term "microperoxisomes" to distinguish these peroxisomes from the better-known larger peroxisomes of liver and kidney.

Acid Phosphatase↗
PubMed1996

Characterization of differing effects caused by homeopathically prepared and conventional dilutions using cytochrome P450 2E1 and other enzymes as detection systems.

Determination of cytochrome P450 2E1 activity was carried out via hydroxylation of the synthetic substrate p-nitrophenol to p-nitrocatechol. Crude microsomal preparation isolated from rat liver served as source for cytochrome P450 2E1. Under assay conditions guaranteeing a linear course of the reaction the cytochrome P450 2E1 was stimulated in the presence of a 10(-6) dilution of As2O3 corresponding to 0.915 microM final concentration compared with control. All other concentrations of As2O3 used inhibited the enzyme activity more or less drastically. Furthermore, we used this enzyme system to study the influence of arsenicum album (As2O3) and potassium cyanatum (KCN) in homeopathically prepared (i.e., by consecutive 1:10 steps) and conventional dilutions. We found significant differences between the effects caused by homeopathic potencies (D) and equally concentrated dilutions on catalytic activity of cytochrome P450 2E1. Such differing effects were observed in the case of arsenicum album (As2O3) between D4/10(-4) and D6/10(-6) and in the case of potassium cyanatum (KCN) between D6/10(-6) and D12/10(-12). When we used glutathione-S-transferases and uricase we also found different effects mediated by potencies and conventional dilutions. The results obtained suggest that these three enzyme systems are appropriate detection systems to hunt out differing effects of differently prepared dilutions of specific test substances.

Animals↗
PubMed1996

Nucleotide sequence of the uricase gene from Bacillus sp. TB-90.

The nucleotide sequence of the uricase gene from the thermophilic bacterium Bacillus sp. TB-90 was determined. The primary structure of the uricase deduced from the nucleotide sequence comprised 332 amino acids, with a total molecular mass of 37,994 Da. The molecular mass of the subunit of the uricase produced by the transformant of Escherichia coli agreed well with this value. However, the molecular mass of a subunit of the uricase produced by Bacillus sp. TB-90 was found to be 34,000 Da by SDS-PAGE. The difference between these molecular masses was attributed to processing of the C-terminal 13 amino acid residue in Bacillus sp. TB-90. Comparison of the enzymatic properties of both uricases showed that the thermostability of the uricase produced by the transformant was enhanced by about 10 degrees C in comparison to that produced by Bacillus sp. TB-90.

Amino Acid Sequence↗