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Biomedical subjects

F Hu

Publications and source records attributed to F Hu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and CCR2-64I) in East Asian and world populations and its implication in AIDS epidemiology.

Chemokine receptor CCR2 and stromal-derived factor (SDF-1) are involved in HIV infection and AIDS symptom onset. Recent cohort studies showed that point mutations in these two genes, CCR2-64I and SDF1-3'A, can delay AIDS onset > or = 16 years after seroconversions. The protective effect of CCR2-64I is dominant, whereas that of SDF1-3'A is recessive. SDF1-3'A homozygotes also showed possible protection against HIV-1 infection. In this study, we surveyed the frequency distributions of the two alleles at both loci in world populations, with emphasis on those in east Asia. The CCR2-64I frequencies do not vary significantly in the different continents, having a range of 0.1-0.2 in most populations. A decreasing cline of the CCR2-64I frequency from north to south was observed in east Asia. In contrast, the distribution of SDF1-3'A in world populations varies substantially, and the highest frequency was observed in Oceanian populations. Moreover, an increasing cline of the SDF1-3'A frequency from north to south was observed in east Asia. The relative hazard values were computed to evaluate the risk of AIDS onset on the basis of two-locus genotypes in the east Asian and world populations.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Mechanisms for the diminished neutrophil exudation to secondary inflammatory sites in infected patients with a systemic inflammatory response (sepsis).

OBJECTIVE: To determine the mechanism for the reduced polymorphonuclear neutrophil exudation to secondary inflammatory sites in critically ill patients with infection and systemic inflammatory response (sepsis). DESIGN: Prospective cohort study. SETTING: Research laboratory and integrated intensive care unit of a tertiary care university-affiliated teaching hospital. PATIENTS: Healthy subjects or critically ill patients with confirmed infection and a systemic inflammatory response (septic patients). MEASUREMENTS AND MAIN RESULTS: We found that polymorphonuclear neutrophil delivery to a secondary inflammatory site (skin window blisters) is reduced by >70% in humans with sepsis, defined as serious infection and a systemic inflammatory response compared with healthy controls. The expression of the endothelial adhesion molecules intercellular adhesion molecule-1, E-selectin and P-selectin in microvessels from skin biopsies was comparable in the two study groups. Also, CD11a and CD11b levels were equal in circulating polymorphonuclear neutrophils (PMNs) from both study groups. Both adhesion molecules were markedly and equally up-regulated during exudation. Circulating PMNs from septic patients showed marked shedding of L-selectin compared to those of healthy controls, with a corresponding increase in their plasma L-selectin levels. An increased concentration gradient between plasma and exudate fluid was found for tumor necrosis factor-alpha and interleukin-8 in septic patients, but not for C5a. The phagocytic and bactericidal capacity of septic patient circulating PMNs was higher then in healthy control patients, but these differences were lost after exudation. There were no major differences in oxidative burst or intracellular calcium flux of circulating PMNs from the two study groups. Polymorphonuclear neutrophil exudation primed both responses to different extents. CONCLUSIONS: Septic patients deliver fewer PMNs to secondary inflammatory sites. In addition, neutrophil exudation results in loss of the small priming effect for phagocytosis and bactericidal function induced by sepsis. Failure to produce a gradient to C5a and intravascular shedding of L-selectin may be responsible for this sepsis-induced reduction in neutrophil exudation to secondary inflammatory sites.

Biomarkers↗
PubMed1999

Rickettsia prowazekii transports UMP and GMP, but not CMP, as building blocks for RNA synthesis.

Rickettsia prowazekii, the etiological agent of epidemic typhus, is an obligate intracellular bacterium and is apparently unable to synthesize ribonucleotides de novo. Here, we show that as an alternative, isolated, purified R. prowazekii organisms transported exogenous uridyl- and guanylribonucleotides and incorporated these labeled precursors into their RNA in a rifampin-sensitive manner. Transport systems for nucleotides, which we have shown previously and show here are present in rickettsiae, have never been reported in free-living bacteria, and the usual nucleobase and nucleoside transport systems are absent in rickettsiae. There was a clear preference for the monophosphate form of ribonucleotides as the transported substrate. In contrast, rickettsiae did not transport cytidylribonucleotides. The source of rickettsial CTP appears to be the transport of UMP followed by its phosphorylation and the amination of intrarickettsial UTP to CTP by CTP synthetase. A complete schema of nucleotide metabolism in rickettsiae is presented that is based on a combination of biochemical, physiological, and genetic information.

Binding, Competitive↗
PubMed1999

A low voltage-activated Ca2+ current mediates cytokine-induced pancreatic beta-cell death.

Insulin-dependent diabetes mellitus is characterized by the selective destruction of pancreatic beta-cells. Chronic treatment with cytokines induced a low voltage-activated (LVA) Ca2+ current in mouse beta-cells. The concomitant increase in the basal cytoplasmic free Ca2+ concentration ([Ca2+]i) was associated with DNA fragmentation and cell death. Antagonists of LVA Ca2+ channels prevented this elevation of basal [Ca2+]i and DNA fragmentation and reduced the percentage of cell death. Exposure to cytokines did not affect the profile of Ca2+ currents or basal [Ca2+]i in glucagon-secreting alpha-cells. An increased Ca2+ signal through LVA Ca2+ channels may thus be a key feature in cytokine-induced beta-cell destruction.

Animals↗
PubMed1998

Northern blot identification of mRNA containing sequence for protein allergen, Alt a1, in eight strains of Alternaria alternata.

BACKGROUND: Concentrations of Alt a1, a major allergen from Alternaria alternata extracts, exhibit significant batch-to-batch variability. This variability may result from basic strain-related genetic differences or from environmental influences such as growth conditions or extraction methods. OBJECTIVE: The objective of this work is to determine if strain-to-strain allergen variability in Alternaria alternata, Alt a1 allergen occurs at the nucleic acid level. METHODS: We compared the content of mRNA for a segment known to contain sequence coding for the reported N-termini of this allergen in eight strains of Alternaria obtained from three individual sources grown under identical conditions. RNA was extracted from rapidly growing mycelia and analyzed by northern blot analysis for the content of a specific segment containing sequence for the Alt a1 allergen. Blots were also analyzed for the content of a specific 5.8S rRNA segment. RESULTS: The size of the mRNA for this protein was about 700 bases. Sequence for the specific segment was found in all of the eight strains tested. When normalized for extraction variabilities using the content of 5.8S rRNA, the calculated concentrations of Alt a1 mRNA of seven of the eight strains were similar. CONCLUSIONS: The results of these experiments suggest that this Alt a1 related allergen sequence is found in many strains of Alternaria and that variabilities in allergen protein content noted previously result from posttranslational events.

Allergens↗
PubMed1998

[Laboratory diagnosis of Chlamydia trachomatis and Ureaplasma urealyticum of chronic prostatitis].

Prostatic fluid taken from 1038 cases of chronic prostatitis were detected by fluorescent monoclonal antibody technique and isolating cultural method for Chlamydia Trachomatis (CT) and Ureaplasma Urealyticum (UU). The control group consisted of 80 cases. CT and UU were not found in control group. The positive rates of CT and UU infection were 28.4% and 33.0% respectively in the tested group whose cases were abacterial prostatitis. The results suggested that CT and UU are pathogens causing chronic abacterial prostatitis.

Adult↗
PubMed1998

[Detection of interleukin-8 and nitric oxide in chronic prostatitis].

We detected levels of interleukin-8(IL-8) and nitric oxide(NO) in 62 prostatic fluids. The results were that microbiologic exam, IL-8 content, and NO level in control group were all negative; there was not significant difference on the microbiologic exam and NO level between the chronic prostatitis group and non-prostatitis group; there was significant difference between two groups of IL-8 positive ratio. These results suggest that the IL-8 detected in the prostatic fluid of patients with prostatitis may be a diagnostic indicator of prostatic infection.

Adult↗
PubMed1998

[Grouping of thoracic lymph nodes on CT scan according to American Thoracic Society classification].

OBJECTIVE: To assess the usefulness of the classification developed by the American Thracic Society (ATS) in the grouping of thoracic lymph nodes on CT scan. METHODS: Ten patients suffered from lymphoma (5 cases), sarcoidosis (2 cases) and metastatic lymphadenopathy (3 cases) were examinated with CT. The intrathoracic lymph nodes were grouped according to the ATS nodal classification. RESULTS: Six areas were divided on the CT scans: (1) between the upper margin of the sixth cervical vertebra and the pulmonary apex, including nodes in group 1R/L; (2) between the pulmonary apex and the upper margin of the aortic arch, including nodes in group 2R/L and 6; (3) between the upper margin of aortic arch and the carina, including nodes in group 4R/L, 5, 6 and 10R; (4) within 3 cm below carina, including nodes in group 7 and 10R/L; (5) between 3 cm from subcarina and the top of diaphragm, including nodes in group 8R/L and 14R/L; (6) intrapulmonary area, distal to the upper lobe bronchi, including nodes in group 11R/L. CONCLUSION: The division of lymph nodes into six areas on CT scan makes the ATS lymph node classification more easily applicable.

Humans↗
PubMed1998

[The relationship between Helicobacter pylori and expression of c-met oncogene in gastric precancerous lesions].

OBJECTIVES: To determine whether there is a relationship between the presence of H. pylori and alteration of c-met oncogene and to estimate the role of H. pylori in the development of gastric carcinoma. METHODS: 110 patients with histopathologically proven chronic gastritis were studied. We demonstrated expression and overexpression rates of c-met oncogene by using immunohistochemical staining. RESULTS: For chronic superficial gastritis, chronic atrophic gastritis, intestinal mataplasia and dysplasia, the expression rates were 22.2%, 44.1%, 67.5% and 61.9%. The overexpression rates were 5.5%, 26.4%, 37.8% and 38.1% respectively. The positive rates of c-met oncogene protein were high among patients infected with H. pylori than those with no H. pylori infection (63% vs 32%). In the precancerous lesions of cellular atrophy, intestinal mataplasia and dysplasia, the expression rates of H. pylori positive patients were higher (68.9%) than those of H. pylori negative patients (30.5%) (P < 0.05). CONCLUSIONS: H. pylori is involved in the expression of c-met oncogene.

Female↗
PubMed1998

[Determination of avermictin in avermictin tablet by high performance liquid chromatography].

A method for the separation and determination of avermictin in avermictin tablet by reversed-phase high performance liquid chromatography (RP-HPLC) was developed. Operating conditions were as follows: TSK-GEL C18 column, 250 mm x 4.6 mm i.d., MeOH-H2O (75:25, V/V) mobile phase with a flow rate of 1.0 mL/min, and UV detection at 245 nm. The results showed that the active constituents avermictin B1a and B1b can by separated effectively. The relative standard deviations were 2.56% and 1.31%, respectively (n = 6). The method is accurate, rapid and simple, and provides a scientific basis for industrial production and quality control of avermictin tablet.

Animals↗
PubMed1997

Endothelin reactivity and receptor profile of pulmonary vessels in postobstructive pulmonary vasculopathy.

Chronic ligation of one pulmonary artery results in pulmonary vascular remodeling and bronchial angiogenesis, collectively known as postobstructive pulmonary vasculopathy (POPV). To determine whether the reactivity of pulmonary vessels to endothelins (ET) was altered in POPV and to explore potential mechanisms, we ligated the left main pulmonary artery of 18 rats. Four weeks later, using a lung explant technique, we compared POPV lungs with controls for contractile responses of intrapulmonary vessels to ET-1 and ET-3 and for relaxant responses to ET-1 and sodium nitroprusside (SNP) after precontraction with U-46619. Morphometric measurements were made on vessels studied pharmacologically. Competition receptor binding studies with 125I-labeled ET-1 and unlabeled ET-1 and BQ-123 were performed using membrane proteins of pulmonary vessels. We found, in arteries, that contractile responses to ET-1 and ET-3 were significantly increased and that relaxant responses to ET-1 but not to SNP were reduced; in veins, only relaxation to SNP was increased. Morphometry showed that arteries and veins in POPV had reduced diameters without altered muscle thickness. Receptor binding studies showed that the proportion of ETA receptors in arteries was significantly increased in POPV (66%) vs. controls (54%). We conclude that, in POPV, the increase in reactivity to ET-1 and ET-3 is primarily related to an augmented proportion of ETA receptors.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

[The relationship of the permeability coefficients of testosterone with solubility parameters of vehicles].

The effects of vehicles on the penetration through rat skin of testosterone were investigated. The solubilities of testosterone in various vehicles and the fluxes through rat abdomen skin had been determined. The solubility parameters of testosterone (delta i) and vehicles (delta v(n)) were calculated by Hildebrand's method. There was a good inverse parabola correlation between the log permeability coefficients (logp) and (delta v(n)). When delta v(n) approched delta i the permeability coefficients of testosterone approched the minimum as its limit.

Animals↗
PubMed1997

Impact mass chemotherapy with praziquantel on schistosomiasis control in Fanhu village, People's Republic of China.

The paper describes the endemic situation of schistosomiasis japonica in Fanhu village, Poyang Lake region, China and the effect of the strategy of combining annual mass chemotherapy with health education on schistosomiasis control in the community. The results showed that the prevalence of infection with schistosome reduced form 26.0% in 1992 to 10.7% in 1994, the intensity of infection in residents decreased from 1.92 in 1992 to 0.55 in 1994 and the condition of hepatomegaly, splenomegaly and liver fibrosis also improved after chemotherapy in the individuals in the case prospective study. Moreover, the future strategies of schistosomiasis control in this area have been suggested according to the transmission of schistosomiasis in the lake region and the effect of anti-schistosomiasis control indifferent populations.

Adolescent↗
PubMed1997

[A study on polycyclic aromatic hydrocarbon-DNA adduct in lung cancer patients exposed to indoor coal-burning smoke].

The objective of this study is to explore the etiology and early risk evaluation of lung cancer in Xuanwei County, Yunnan Province of China. Polycyclic aromatic hydrocarbon (PAH)-DNA adduct in brushing cells from fibrobronchoscopy was determined in 30 cases with lung cancer in Xuanwei County and 10 controls in Kunming, Yunnan Province by 32P-postlabelling assay. Results showed that PAH-DNA levels in lung cancer patients of Xuanwei County were much more higher than those in controls. It suggested that air pollution caused by indoor coal-burning associated directly with the occurrence of lung cancer, and detection of DNA adduct could be used as an indicator for its risk assessment in population.

Air Pollution, Indoor↗
PubMed1996

Shedding of L-selectin as a mechanism for reduced polymorphonuclear neutrophil exudation in patients with the systemic inflammatory response syndrome.

BACKGROUND: It has been recently shown that patients with the systemic inflammatory response syndrome (SIRS) have reduced neutrophil exudation. OBJECTIVE: To determine whether reduced neutrophil exudation, seen in patients with SIRS, is related to differential expression of cell adhesion molecules (CAMs), by studying endothelial and neutrophil CAM expression. SETTING: A tertiary care surgical intensive care unit in a university teaching hospital. DESIGN: Twenty-six patients with SIRS were compared with 18 healthy age-matched control subjects. Blister-type skin windows were created. Exudative neutrophils were harvested, and CAM expression was quantitated by using flow cytometry. Endothelial CAM expression was studied with immunohistochemical methods by using skin biopsy specimens that were taken following subdermal injections of saline solution or tumor necrosis factor alpha. RESULTS: Despite a significant reduction in neutrophil exudation in patients, we found no difference in the baseline expression of the endothelial intercellular adhesion molecule 1, P-selectin, or E-selectin in patients vs that in control subjects. There was a significant increase in E-selectin staining in response to recombinant human tumor necrosis factor alpha in patients with SIRS, but not in control subjects. However, up-regulation of P-selectin did not occur in patients in response to recombinant human tumor necrosis factor alpha, as was observed in control subjects. L-selectin expression on circulating neutrophils was lower in patients than in control subjects, while soluble serum L-selectin levels were higher. CONCLUSIONS: Alterations in neutrophil L-selectin, not endothelial CAMs, are important in decreased neutrophil exudation. Reduced levels of neutrophil L-selectin associated with increased levels of serum L-selectin in patients with SIRS suggest premature intravascular shedding of neutrophil L-selectin. This would compromise the initial interaction between neutrophils and the endothelium, and, consequently, impede exudation.

Case-Control Studies↗