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Biomedical subjects

W Qu

Publications and source records attributed to W Qu.

At least 55 records · Page 3Linked to original sources
PubMed1999

PGE(2) stimulates O(2) uptake in hepatic parenchymal cells: involvement of the cAMP-dependent protein kinase.

The aim of this study was to determine which PGE(2) receptors and signal transduction pathways are responsible for the stimulation of oxygen uptake in liver. Hepatic parenchymal cells isolated from female Sprague-Dawley rats were incubated either with PGE(2), 17-phenyl-omega-trinor PGE(2) (an EP(1)-specific agonist), or 11-deoxy PGE(1) (an EP(2)/EP(4)-specific agonist), and oxygen consumption was measured. Both PGE(2) and 11-deoxy PGE(1) stimulated oxygen consumption. However, an EP(1) agonist was without effect. Although PGE(2) elevated intracellular calcium, this occurred at concentrations approximately 500-fold lower than that required to stimulate oxygen uptake. PGE(2)-stimulated increases in cAMP formation correlated well with the increase in oxygen consumption. Dibutyryl cAMP also increased oxygen consumption. Furthermore, N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide, a cell-permeable inhibitor of protein kinase A (PKA), reduced the stimulation of oxygen uptake by PGE(2). Incubation of isolated parenchymal cell mitochondria with the purified catalytic subunit of PKA and ATP increased both state 3 rates of oxygen uptake and the respiratory control ratio by approximately 50%. Activation of these events was prevented by incubation with the PKA inhibitory peptide, PKI. These findings are consistent with the hypothesis that PGE(2) stimulates oxygen consumption via an EP(2) and/or EP(4) subclass of receptors through the actions of cAMP on a cAMP-dependent protein kinase.

1-Methyl-3-isobutylxanthine↗
PubMed1999

Allergic lung responses are increased in prostaglandin H synthase-deficient mice.

To investigate the function of prostaglandin H synthase-1 and synthase-2 (PGHS-1 and PGHS-2) in the normal lung and in allergic lung responses, we examined allergen-induced pulmonary inflammation and airway hyperresponsiveness in wild-type mice and in PGHS-1(-/-) and PGHS-2(-/-) mice. Among nonimmunized saline-exposed groups, we found no significant differences in lung function or histopathology, although PGE(2) was dramatically reduced in bronchoalveolar lavage (BAL) fluid from PGHS-1(-/-) mice, relative to wild-type or PGHS-2(-/-) mice. After ovalbumin sensitization and challenge, lung inflammatory indices (BAL cells, proteins, IgE, lung histopathology) were significantly greater in PGHS-1(-/-) mice compared with PGHS-2(-/-) mice, and both were far greater than in wild-type mice, as illustrated by the ratio of eosinophils in BAL fluid (8:5:1, respectively). Both allergic PGHS-1(-/-) and PGHS-2(-/-) mice exhibited decreased baseline respiratory system compliance, whereas only allergic PGHS-1(-/-) mice showed increased baseline resistance and responsiveness to methacholine. Ovalbumin exposure caused a modest increase in lung PGHS-2 protein and a corresponding increase in BAL fluid PGE(2) in wild-type mice. We conclude that (a) PGHS-1 is the predominant enzyme that biosynthesizes PGE(2) in the normal mouse lung; (b) PGHS-1 and PGHS-2 products limit allergic lung inflammation and IgE secretion and promote normal lung function; and (c) airway inflammation can be dissociated from the development of airway hyperresponsiveness in PGHS-2(-/-) mice.

Allergens↗
PubMed1999

[Distribution of genotypes of alcohol dehydrogenase 2 and aldehyde dehydrogenase 2 in Japanese twin children].

OBJECTIVE: In order to prevent alcohol related deseases, this study investigated the distribution of the genes controlling alcohol metabolism in Japan's twin. METHODS: Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) technique was used to measure the control gene of alcohol metabolized enzymes and the genotypes of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2), which were distributed in Japan's twins. At the same time, according to the difference in genotypes, the sensitive individuals were screened from the study subjects. RESULTS: The distribution of ADH2 and ALDH2 genes were consistent with the Hardy-weinberg equation. The three genotypes of ADH2 gene were ADH2(1)/ADH2(1) (1.1%), ADH2(1)/ADH2(2) (44.6%) and ADH2(2)/ADH2(2) (54.3%). And those of ALDH2 gene were ALDH2(1)/ALDH2(1) (41.3%), ALDH2(1)/ALDH2(2) (39.1%) and ALDH2(2)/ALDH2(2) (19.6%). The frequency of ADH2 and ALDH2 genes was 0.255, 0.745 and 0.609, 0.391 respectively. CONCLUSION: Not only the distribution of genotypes of ADH2 and ALDH2 is known, but also the sensitive individuals are found, which can help prevent alcohol related disease.

Alcohol Dehydrogenase↗
PubMed1999

[Effects of alcohol and metabolite acetaldehyde on the proliferation of astroglial cells of fetal brain].

To explore the mechanism of the retardation and abnormality of nerve system development induced by drinking alcohol during pregnancy, 3H-TdR incorporation was used to study the proliferation of astroglial cells of fetal brain induced by alcohol and its metabolite acetaldehyde in vitro. The results showed that alcohol and acetaldehyde obviously restrain the proliferation of astrocytes. The effect of restrain induced by acetaldehyde is stronger than that by alcohol. Nerve system development retardation and abnormality resulted from alcohol is likely to be the restrain of proliferation induced by alcohol and its metabolite acetaldehyde.

Acetaldehyde↗
PubMed1998

A multifaceted study of human papillomavirus and prostate carcinoma.

BACKGROUND: The presence of human papillomavirus (HPV) in the prostate and its role in prostate carcinoma are in dispute. To address these issues, two laboratories with extensive HPV experience were selected to test specimens from two populations at different risk for prostate carcinoma, using three different polymerase chain reaction (PCR) assays and two serologic assays for HPV. METHODS: The cases were comprised of 51 African-American (men at high risk for prostate carcinoma) and 15 Italian (men at intermediate risk for prostate carcinoma) men with prostate carcinoma. Controls were 108 African-American men and 40 Italian men with histologically proven benign prostate hypertrophy (BPH). Prostate tissue was obtained from each patient at surgery and immediately frozen in liquid nitrogen. The PCR primer sets included two (MY09/MY11 and GP5+/ GP6+) that amplify different regions of L1 and a third (WD66,67,154/WD72,76) targeted to E6. Sensitivity in the 2 L1 PCR assays was shown to be 1 HPV DNA genome per 100 cells. Serum antibodies to HPV-16 and HPV-11 virus-like particles (VLPs) were detected using enzyme-linked immunosorbent assays. RESULTS: All available prostate carcinoma tissue specimens (n = 63) and BPH specimens from selected controls (n = 61) were tested by PCR. Human beta-globin DNA could be amplified from all specimens except three carcinomas, but no HPV DNA was detected in any case or control specimens by MY09/MY11 or E6 PCR. Microdissection of 27 carcinoma specimens was conducted to minimize nontumor DNA, but results remained negative by MY09/MY11 and GP5+/GP6+ PCR. In addition, serum specimens in cases (n = 63) and controls (n = 144) showed no differences in their responses against HPV-16 (P = 0.54) or HPV-11 VLPs (P = 0.64). CONCLUSIONS: The findings suggest that HPV is not associated with prostate carcinoma, and that HPV DNA is not at all common in the prostate glands of older men.

Aged↗
PubMed1998

Nutritional status modulates rat liver cytochrome P450 arachidonic acid metabolism.

Alterations in nutritional status affect hepatic cytochrome P450 levels. Since cytochromes P450 participate in the metabolism of arachidonic acid, we hypothesized that changes in liver P450 arachidonic acid metabolism occur during fasting and refeeding. Male Fisher 344 rats were either fed, fasted 48 hr (F48), fasted 48 hr and then refed 6 hr (F48/R6), or fasted 48 hr and then refed 24 hr (F48/R24). F48 rats had reduced body weight, increased plasma beta-hydroxybutyrate, and reduced plasma insulin compared with the other groups. Although there was no significant change in total liver P450 content, there was a significant 20%, 48%, and 24% reduction in total hepatic microsomal arachidonic acid metabolism in F48, F48/R6, and F48/R24 rats, respectively, compared with fed rats. Epoxygenase activity decreased by 28%, 51%, and 26% in F48, F48/R6, and F48/R24 rats, respectively. In contrast, omega-1 hydroxylase activity increased by 126% in F48 rats compared with fed rats. Immunoblotting revealed that levels of CYP2C11 protein were markedly reduced, whereas levels of CYP2E1 protein were markedly increased in the F48 and F48/R6 groups. In contrast, levels of CYP1A1, CYP1A2, CYP2B1, CYP2J3, CYP4A1, and CYP4A3 were unchanged with fasting/refeeding. Northern blots revealed that levels of CYP2C11 mRNAs were decreased, whereas CYP2E1 mRNAs were increased in F48 and F48/R6 rats. Recombinant CYP2C11 metabolized arachidonic acid primarily to epoxides with preference for the 14(S),15(R)-, 11(R), 12(S)-, and 8(S),9(R)- epoxyeicosatrienoic acid enantiomers. We conclude that (1) nutritional status affects hepatic microsomal arachidonic acid metabolism, (2) reduced epoxygenase activity in F48 and F48/R6 rats is accompanied by decreased levels of CYP2C11, (3) increased omega-1 hydroxylase activity is accompanied by augmented levels of CYP2E1, and (4) the effects of fasting on CYP2C11 and CYP2E1 expression occur at the pretranslational level.

8,11,14-Eicosatrienoic Acid↗
PubMed1998

Sequencing of Escherichia coli O111 O-antigen gene cluster and identification of O111-specific genes.

Shiga toxin (Stx)-producing Escherichia coli strains of serogroup O111 are the most frequently isolated non-O157 strains causing outbreaks of gastroenteritis with hemolytic-uremic syndrome. The O111 O-antigen gene cluster had been cloned and about half of it has been sequenced; we have now sequenced the remainder of the gene cluster, which is 12.5 kb in length and which comprises 11 genes. On the basis of sequence similarity, we have identified all the O-antigen genes expected, including five sugar biosynthetic pathway genes, three transferase genes, the O-unit flippase gene, and the O-antigen polymerase gene. By PCR testing with E. coli strains representing all 166 O-antigen forms, some randomly selected gram-negative bacteria, and Salmonella enterica serovar Adelaide, we showed that four O-antigen genes are highly specific to O111. This work provides the basis for a sensitive test for the rapid detection of E. coli O111. This is important both for decisions related to patient care, because early treatment may reduce the risk of life-threatening complications, and for the detection of sources of contamination.

Antigens, Bacterial↗
PubMed1998

Stimulation of oxygen uptake by prostaglandin E2 is oxygen dependent in perfused rat liver.

The aim of this study was to determine if the effect of prostaglandin E2 (PGE2) on hepatic oxygen uptake was affected by oxygen tension. Livers from fed female Sprague-Dawley rats were perfused at normal or high flow rates (4 or 8 ml . g-1 . min-1) to vary local oxygen tension within the liver lobule. During perfusion at normal flow rates, PGE2 (5 microM) infusion increased oxygen uptake by about 50 micromol . g-1 . h-1; however, when livers were perfused at high flow rates, the increase was nearly twice as large. Simultaneously, glucose output was increased rapidly by about 50%, whereas glycolysis was decreased about 60%. When flow rate was held constant, increases in oxygen uptake due to PGE2 were proportional to oxygen delivery. Infusion of PGE2 into livers perfused at normal flow rates increased state 3 rates of oxygen uptake of subsequently isolated mitochondria by about 25%; however, rates were increased 50-75% in mitochondria isolated from livers perfused at high flow rates. Thus it is concluded that PGE2 stimulates oxygen uptake via mechanisms regulated by oxygen tension in perfused rat liver. High flow rates also increased basal rates of oxygen uptake: this increase was prevented by inactivation of Kupffer cells with GdCl3. In addition, conditioned medium from Kupffer cells incubated at high oxygen tension (75% oxygen) stimulated oxygen uptake of isolated parenchymal cells by >30% and elevated PGE2 production about twofold compared with Kupffer cells exposed to normal air-saturated buffer (21% oxygen). These effects were blocked completely by both indomethacin and nisoldipine. These data support the hypothesis that oxygen stimulates Kupffer cells to release mediators such as PGE2 which elevate oxygen consumption in parenchymal cells, possibly by mechanisms involving cyclooxygenase and calcium channels.

Animals↗
PubMed1997

PCR detection of human papillomavirus: comparison between MY09/MY11 and GP5+/GP6+ primer systems.

Human papillomavirus (HPV) is an etiologic agent of cervical cancer and is the most common sexually transmitted disease in women. PCR amplification of HPV genomes is the most sensitive method for the detection of cervicovaginal HPV. We have compared the two most commonly used PCR primer sets, MY09/MY11 (MY-PCR) and GP5+/GP6+ (GP+-PCR), for the detection of HPV DNA in cervicovaginal lavage samples from 208 women. Oligonucleotide probes for 39 different HPV types were used. Both primer sets amplified a wide spectrum of HPV genotypes and detected similar overall prevalences of 45% (94 of 208) and 43% (89 of 208), respectively. The MY-PCR system detected 27 of 30 (90%) samples with multiple HPV types, whereas the GP+-PCR system detected 14 of 30 (47%) samples with multiple HPV types. Differences in the detection of HPV types 35, 53, and 61 were noted between the two primer systems. Serial dilution of plasmid templates indicated a 3-log decrease in the amplification of HPV type 35 by MY-PCR and HPV types 53 and 61 by GP+-PCR. These results indicate that although the MY-PCR and GP+-PCR identified nearly equivalent prevalences of HPV in a set of clinical samples, differences in the detection of specific types and infections with multiple types were found. Differences in the sensitivities and characteristics of the PCR systems for the detection of HPV within clinical samples should be considered when comparing data between studies and/or in designing new studies or clinical trials.

DNA Primers↗
PubMed1997

Kupffer cells contain a glycine-gated chloride channel.

Here the effect of glycine on intracellular Ca2+ concentration ([Ca2+]i) in cultured Kupffer cells stimulated with lipopolysaccharide (LPS) was investigated to assess the possibility that they contain a glycine-gated chloride channel. LPS (10 micrograms/ml) increased [Ca2+]i rapidly, with peak values reaching 307 +/- 29 nM. Glycine (1 mM) prevented this increase nearly completely. Low concentrations of strychnine (1 microM), a glycine receptor antagonist, reversed the inhibitory effect of glycine completely; however, high concentrations of strychnine (1 mM) mimicked glycine. The effects of glycine and high-dose strychnine were prevented when cells were incubated in chloride-free buffer. Furthermore, potassium (25 mM) and LPS depolarized the Kupffer cell plasma membrane, whereas glycine caused hyperpolarization and prevented depolarization due to potassium and LPS. Moreover, tumor necrosis factor-alpha (TNF-alpha) production in cultured Kupffer cells due to LPS was decreased significantly by glycine. Therefore, it is concluded that Kupffer cells contain a glycine-gated chloride channel similar to that described previously in the central nervous system. Prevention of increases in [Ca2+]i due to LPS by activation of chloride influx reduced synthesis and release of toxic mediators by Kupffer cells.

Animals↗
PubMed1996

Interleukin 2 production in vitro by peripheral lymphocytes in response to human papillomavirus-derived peptides: correlation with cervical pathology.

Human papillomavirus (HPV) is believed to be the major cause of cervical cancer. To investigate whether a cellular immune response, especially a T helper type 1 response, is related to the natural defense against HPV-related cervical lesions, the interleukin 2 response of peripheral blood lymphocytes in vitro to overlapping peptides from HPV-16 E6 and E7 oncoproteins was compared with the degree of cervical cytological abnormality among 140 women in a cross-sectional study. We compared 66 women diagnosed with low-grade squamous intraepithelial lesions (LSIL), 21 with high-grade squamous intraepithelial lesions (HSIL), and 28 with invasive cervical cancer with 25 women who were cytologically normal but previously HPV-16 DNA positive. The fraction showing strong interleukin 2 production against HPV-16 peptides was greatest among cytologically normal women (35%) and declined with increasing disease severity [LSIL] (20%), HSIL, (17%), and cancer patients (7%); X2 test P for the trend = 0.02], whereas the responses against a recall influenza antigen were not significantly different among groups. Our finding suggests that a T helper lymphocyte type 1 response to HPV antigens is associated with disease status. This result may reflect a targeted effect of the disease on immune function or a protective effect of the immune response against disease progression.

Adolescent↗
PubMed1996

Destruction of Kupffer cells increases survival and reduces graft injury after transplantation of fatty livers from ethanol-treated rats.

This study investigated the role of Kupffer cells on survival and graft injury in transplanted fatty livers from rats treated acutely with ethanol. Donor rats were given ethanol (5 g/kg, by mouth) 20 hours before explantation, and liver grafts were preserved in University of Wisconsin cold storage solution for 24 to 42 hours prior to implantation. Blood samples were taken from the inferior vena cava for 3 hours after implantation. During this time, serum aspartate transaminase levels increased gradually from 122 U/L to 597 U/L in control rats, while ethanol treatment elevated values to 2,278 U/L. Gadolinium chloride (20 mg/kg, given intravenously to recipients 24 hours before explantation), a selective inactivator of Kupffer cells, minimized the increase in aspartate transaminase levels significantly. After implantation of grafts cold-stored for 42 hours, survival rates were 88% in control rats but only 33% in ethanol-treated rats. Gadolinium chloride improved survival nearly to control values. Ethanol nearly doubled white blood cell adhesion, an effect also largely blocked by gadolinium chloride. Further, alpha-(4-pyridyl 1-oxid)-N-tert-butylnitrone radical adducts detected in the bile were increased twofold by ethanol treatment. This effect was also reversed by gadolinium chloride. Taken together, these data indicate that survival is poorer and graft injury is greater in fatty livers from ethanol-treated rats. Inactivation of Kupffer cells minimized graft damage, most likely by improving hepatic microcirculation and diminishing lipid peroxidation.

Analysis of Variance↗
PubMed1996

Kupffer cell prostaglandin E2 stimulates parenchymal cell O2 consumption: alcohol and cell-cell communication.

Several studies have demonstrated that ethanol can increase hepatic O2 uptake (e.g., produce a hypermetabolic state); however, a complete explanation of this important phenomenon remains unclear. Here, the effect of conditioned media from Kupffer cells isolated from rats chronically exposed to ethanol on O2 consumption of normal parenchymal cells was studied to evaluate the possibility that cell-cell communication participates in the mechanism of the hepatic hypermetabolic state. Kupffer cells were isolated from rats fed either a liquid control diet or a diet containing ethanol. Kupffer cells were cultured for 4 h, and conditioned media were incubated with parenchymal cells isolated from untreated rats in a closed chamber with an O2 electrode. O2 consumption of parenchymal cells incubated in fresh media or conditioned media from Kupffer cells from untreated rats was approximately 30 microliters.h-1. 10(6) cells-1; however, values were increased by > 30% by conditioned media from Kupffer cells isolated from rats treated with ethanol. Indomethacin, nisoldipine, and boiling the conditioned media blocked this stimulation, suggesting the involvement of eicosanoids. Indeed, prostaglandin E2 (PGE2) added directly to parenchymal cells increased O2 consumption in a dose-dependent manner by nearly 60%. Furthermore, PGE2 levels in conditioned media from Kupffer cells isolated from ethanol-treated rats were elevated about twofold. The addition of endotoxin to cultured cells caused a similar phenomenon. Taken together, these data support the hypothesis that Kupffer cells are activated by ethanol treatment to release mediators such a PGE2, which stimulate O2 consumption in parenchymal cells, possibly by mechanisms involving bacterial endotoxin.

Animals↗
PubMed1995

Food restriction stimulates conjugation of p-nitrophenol in perfused rat liver.

Rates of conjugation of p-nitrophenol were studied in livers from normal and food-restricted rats perfused with either p-nitroanisole or p-nitrophenol. Female Sprague-Dawley rats had ad libitum access to a Purina 5001 nonpurified diet (control) or were given 65% of the intake of controls for 3 weeks. Livers were perfused with oxygenated Krebs-Henseleit buffer using a nonrecirculating system. Maximal rates of conjugation of p-nitrophenol, generated either from the O-demethylation of p-nitroanisole (200 microM) or from the infusion of p-nitrophenol (70 microM), were elevated significantly nearly twofold by food restriction. Thus, food restriction stimulates conjugation in the intact liver cell. Specifically, rates of conjugation were increased from 2.1 +/- 0.2 to 3.7 +/- 0.4 and from 3.3 +/- 0.6 to 5.8 +/- 0.5 mumol/g/h when 200 microM p-nitroanisole or 70 microM p-nitrophenol were infused, respectively. On the other hand, rates of conjugation were not affected by food restriction when low concentrations of p-nitroanisole (50 microM) or p-nitrophenol (20 microM) were infused. Further, food restriction did not alter rates of conjugation in isolated microsomes supplemented with excess UDPGA. Interestingly, both UDP-glucose and UDP-glucuronic acid were increased significantly in liver extracts from food-restricted rats when livers were perfused with high but not low concentrations of p-nitrophenol. Under these conditions, the increase in UDP-glucuronic acid was threefold. Moreover, food restriction increased carbohydrate release from the liver about twofold. Glycogen content was also increased significantly in liver extracts from 8.4 +/- 1.9 to 60.4 +/- 13.8 mmol/kg wet weight by food restriction. Taken together, these data support the hypothesis that food restriction stimulates conjugation of p-nitrophenol concentrations by increasing the supply of the pivotal cofactor UDP-glucuronic acid from carbohydrate reserves (e.g., glycogen).

Animals↗
PubMed1995

Role of Kupffer cells in reperfusion injury in fat-loaded livers from ethanol-treated rats.

Reperfusion injury was studied in blood-free perfused livers from fat-loaded, ethanol-treated rats. Rats were pair-fed a modified Lieber-DeCarli liquid diet containing 36% calories as ethanol or isocaloric maltose-dextrin for 4 to 5 weeks. Reperfusion injury to the liver, which occurs in previously hypoxic regions upon reintroduction of oxygen, was studied in a low-flow, reflow perfusion model. Lactate dehydrogenase in effluent perfusate increased from basal levels of < 1 to 17 IU/g/h in livers from controls, whereas prior alcohol treatment elevated values to 37 IU/g/h. Pretreatment of rats with gadolinium chloride (GdCl3, 20 mg/kg i.v.), a selective Kupffer cell toxicant, minimized lactate dehydrogenase release during reperfusion to 7 to 8 IU/g/h in livers from both groups. Rates of malondialdehyde production were 144 and 166 nmol/g/h during reperfusion in control and alcohol-treated rats, respectively, but values reached only 54 and 79 nmol/g/h after GdCl3 treatment. Interestingly, a typical PBN/carbon-centered free radical adduct signal was detected in bile of livers from ethanol-treated rats, but not in controls or ethanol-treated rats given GdCl3. Portal pressure increased during the reperfusion period in livers from alcohol-treated rats, although not in controls, and GdCl3 reduced it significantly. Taken together, these data indicate that reperfusion injury is greater in fatty livers from alcohol-treated rats in a blood-free model. Inactivation of Kupffer cells minimized reperfusion injury in both control and alcohol-treated rats, most likely by diminishing lipid peroxidation thereby improving hepatic microcirculation.

Animals↗