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Biomedical subjects

J H Dong

Publications and source records attributed to J H Dong.

14 recordsLinked to original sources
PubMed1999

Study of environmental biomonitoring of the Jiaozhou Bay.

The content of 34 elements was determined in tissue samples of several marine bivalve species collected from various sites in the Jiaozhou Bay. The scope of the study was to determine the most suitable bivalve species to be used for environmental biomonitoring and to evaluate the environmental status of the bay. Clams exhibited higher elemental contents than oysters and they are the major marine bivalve species in the Jiaozhou Bay; therefore, we consider clams to be more suitable than oysters as bioindicators for evaluating the environmental status of the area. Increased elemental levels in clam tissues indicate polluted sites. Also, increased elemental levels in mussels point to possible pollution from tourism development at one selected site.

Animals↗
PubMed1996

Elevations of hepatic quinone reductase, glutathione, and alpha- and mu-class glutathione S-transferase isoforms in mice with chronic hepatitis: a compensatory response to injury.

Hepatic levels of GSH and Phase II detoxication enzymes were compared to biochemical and histological indices of hepatic damage in 4- to 76-week-old nontransgenic mice and their transgenic littermates that overexpress the hepatitis B virus large envelope protein. The mice were fed a low-sucrose AIN-76A diet ad libitum. Hepatic-specific activities of quinone reductase (QR) and glutathione S-transferase (GST) were increased 2- to 10-fold beginning at 12 weeks of age in transgenic mice and correlated with increases in serum alanine aminotransferase (ALT) (r = 0.84 and 0.59, respectively). Quantitative histological analysis demonstrated that apoptosis was the predominant feature in 4- to 12-week-old transgenic mice, whereas necrosis and inflammation predominated at later time points. Surprisingly, 3-fold elevations in ALT were observed beginning at 52 weeks of age in nontransgenic mice, and hepatic-specific activities of QR and GST were also modestly increased in elderly nontransgenic animals. In contrast to transgenic mice, apoptosis was not a prominent feature. The strongest histological correlates to ALT in 4- to 76-week-old nontransgenic mice were necrosis and inflammation (r > 0.96), which in turn may have been evoked by hepatic fat accumulation. Profiles of specific GST isoforms were quantitated chromatographically and identified by sequencing tryptic digests. The Ya1 subunit of alpha-class GST was markedly increased from undetectable levels in transgenic mice, while more modest increases were observed in nontransgenic mice more than 1 year old. Fivefold elevations of the Yb1 subunit, a constitutively expressed mu-class GST, were found in transgenic mice older than 4 weeks of age, while 2-fold increases were observed in nontransgenic animals that were more than 1 year old. These studies demonstrate that selected increases in Phase II detoxication enzymes are a stereotyped response to chronic hepatitis that is strikingly reminiscent of the treatment of mice with anticarcinogenic enzyme inducers.

Aging↗
PubMed1992

[Multiple organ failure following severe acute pancreatitis: its clinically patterns and pathogenetic factors].

To detect the clinical course and possible pathogenetic factors of multiple organ failure (MOF) after severe acute pancreatitis (SAP), we investigated retrospectively 70 consecutive patients with SAP for a 16-year period. Two different patterns of MOF were identified: rapid-single phase MOF developed early after SAP attack, and delayed tow-phase MOF developed progressively and sequentially with a lag phase. The clinical course of MOF was characterized by a severely systemic inflammatory response. Clinical variables associated with the evolution of MOF included early circulatory shock, pancreatic sepsis and severe pancreatic necrosis, which might be the leading one. It is suggested that the generalized inflammatory response triggered by the toxic focus seems to be the final common pathway linking SAP with MOF syndrome.

Abscess↗
PubMed1986

Characterization of purified cytochrome c1 from Rhodobacter sphaeroides R-26.

Cytochrome c1 from a photosynthetic bacterium Rhodobacter sphaeroides R-26 has been purified to homogeneity. The purified protein contains 30 nmol heme per mg protein, has an isoelectric point of 5.7, and is soluble in aqueous solution in the absence of detergents. The apparent molecular weight of this protein is about 150,000, determined by Bio Gel A-0.5 m column chromatography; a minimum molecular weight of 30,000 is obtained by sodium dodecylsulfate polyacrylamide gel electrophoresis. The absorption spectrum of this cytochrome is similar to that of mammalian cytochrome c1, but the amino acid composition and circular dichroism spectral characteristics are different. The heme moiety of cytochrome c1 is more exposed than is that of mammalian cytochrome c1, but less exposed than that of cytochrome c2. Ferricytochrome c1 undergoes photoreduction upon illumination with light under anaerobic conditions. Such photoreduction is completely abolished when p-chloromercuriphenylsulfonate is added to ferricytochrome c1, suggesting that the sulfhydryl groups of cytochrome c1 are the electron donors for photoreduction. Purified cytochrome c1 contains 3 +/- 0.1 mol of the p-chloromercuriphenylsulfonate titratable sulfhydryl groups per mol of protein. In contrast to mammalian cytochrome c1, the bacterial protein does not form a stable complex with cytochrome c2 or with mammalian cytochrome c at low ionic strength. Electron transfer between bacterial ferrocytochrome c1 and bacterial ferricytochrome c2, and between bacterial ferrocytochrome c1 and mammalian ferricytochrome c proceeds rapidly with equilibrium constants of 49 and 3.5, respectively. The midpoint potential of purified cytochrome c1 is calculated to be 228 mV, which is identical to that of mammalian cytochrome c1.

Cytochrome c Group↗
PubMed1986

Immunological comparison of the b and c1 cytochromes from bovine heart mitochondria and the photosynthetic bacterium Rhodopseudomonas sphaeroides R-26.

Antibodies against cytochromes b and c1 of bovine heart mitochondria and the photosynthetic bacterium, Rhodopseudomonas sphaeroides R-26, were raised in rabbits. The purified antibodies showed high titers against their respective antigens in enzyme-linked immunosorbent assays. Less than 15% cross-reactivity between the mitochondrial and bacterial cytochromes was detected. Although antibodies against mitochondrial cytochrome b did not inhibit the mitochondrial cytochrome b-c1 complex, a 70% inhibition was obtained when these antibodies were incubated with delipidated mitochondrial cytochrome b-c1 complex prior to reconstitution with phospholipids indicating that the catalytic site(s) of mitochondrial cytochrome b are masked by phospholipids. On the other hand, antibodies against bacterial cytochrome b showed significant inhibition of the intact bacterial cytochrome b-c1 complex, indicating that some of the catalytic site epitopes of bacterial cytochrome b are exposed to the hydrophilic environment. Similar to antibodies against mitochondrial cytochrome b, antibodies against bacterial cytochrome b inhibited 50% activity of the mitochondrial cytochrome b-c1 complex only when they were incubated with the delipidated mitochondrial cytochrome b-c1 complex prior to reconstitution with phospholipids, indicating that the common epitopes between the cytochromes b are masked by phospholipids. Antibodies against mitochondrial and bacterial cytochromes c1 completely inhibited their respective cytochrome b-c1 complexes but no cross-immunoinhibition was observed. However, when antibodies against bacterial cytochrome c1 were incubated with the delipidated mitochondrial cytochrome b-c1 complex before reconstitution with phospholipids, a 65% inhibition was observed, indicating that the common epitopes between the cytochromes c1 were also somewhat masked by phospholipids. Antibodies against mitochondrial cytochrome c1 inhibited 70% of the succinate oxidase activity in the intact mitochondria preparation, but no inhibition was observed in submitochondrial particles, indicating that some mitochondrial cytochrome c1 epitopes are exposed to the cytoplasmic side.

Animals↗
PubMed1986

The EPR spectra of the cytochrome b-c1 complex of Rhodopseudomonas sphaeroides.

The purified cytochrome b-c1 complex of Rhodopseudomonas sphaeroides has two b cytochromes distinguishable by optical, thermodynamic and electron paramagnetic resonance criteria (gz values are approximately equal to 3.75 and approximately equal to 3.4). EPR features typical of a Rieske iron sulfur cluster (g values of 2.03 1.90 and 1.81) and a c1 type cytochrome (g approximately equal to 3.4) were also observed. The b and c1 cytochromes were individually purified from the complex. The cytochrome c1 retained its native EPR spectrum. The b cytochrome lost over 90% of the intensity from the 'b566 type' heme site (g approximately equal to 3.75), while the 'b561 type' heme site (g approximately equal to 3.4) retained its native EPR spectrum.

Ascorbic Acid↗