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Biomedical subjects

Hong Du

Publications and source records attributed to Hong Du.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Transpupillary thermotherapy for circumscribed choroidal hemangioma].

OBJECTIVE: To evaluate the efficacy of transpupillary thermotherapy (TTT) on circumscribed choroidal hemangioma. METHODS: Ten eyes of 10 cases with circumscribed choroidal hemangioma (age 16-48, average 34.4) were included in the present study. Six cases had previous green laser (4 argon and 2 krypton) photocoagulation, TTT as a primary treatment was used for other 4 cases without previous laser application. Fluorescein angiography, visual acuity, anterior segment and fundus examination, perimetry test, FFA/ICGA and ultrasonography were performed in all patients before the treatment. One to five infra red diode laser spots (810 nm with power of 800-1200 mW, diameter of 3 mm) were delivered on the surface of tumor with 60 seconds exposure, additional 10-20 seconds exposure was used in some cases. Second treatment was given 1-3 month later if there was active leakage demonstrated by fluorescein angiography. The followed-up period was 6-36 months (averaged 14.5 month). RESULTS: After transpupillary thermotherapy, 9 eyes (90%) showed partial regression of the tumor. Average visual acuity was 0.25 and 0.6 before and after TTT, respectively. Six patients showed improvement of vision acuity, but vision acuity in 4 patients with cystic macular degeneration remained unchanged. No recurrences were observed within follow-up averaged 14.5 months. Transpupillary thermotherapy did not associate with any significant complications. CONCLUSION: Transpupillary thermotherapy is effective to treat circumscribed hemangioma of choroid either as a primary treatment or supplementary therapy to previous laser photocoagulation.

Adolescent↗
PubMed2005

Epidemiological features of severe acute respiratory syndrome in Beijing urban and suburb areas in 2003.

OBJECTIVE: To describe the epidemiologic features of an outbreak of severe acute respiratory syndrome (SARS) in urban and suburb areas in Beijing and to explore their differences between these two areas. METHODS: Data of SARS cases were collected from daily notification of China Ministry of Health and a database of infectious diseases was established by the Beijing Municipal Center for Disease Prevention and Control (BCDC). All the data were put into dataset files by Microsoft Excel-2000 and analyzed with SPSS version 10.0 software. RESULTS: The respective urban incidence and mortality rate were 29.06 and 2.21 per 100,000, while the case fatality rate was 7.62%. In contrast, the respective suburb incidence and mortality rate were 10.61 and 0.78 per 100,000, and the case fatality rate was 7.32%. No significant differences were found in demographic characteristics between the urban and suburb areas. CONCLUSION: Beijing urban area suffered a more serious SARS epidemic than the suburb area in 2003.

Adolescent↗
PubMed2004

Mutation of a lysine residue in a homeodomain generates dominant negative thyroid transcription factor 1.

Thyroid transcription factor 1 (TTF-1) is a 42 kDa homeodomain (HD) containing the tissue-specific transcription factor of Nkx2 family members (also termed TEBP and Nkx2.1). TTF-1 is an essential transcription factor required for lung development and lung-specific gene expression. Transgenic mice carrying TTF-1 DNA-binding site mutations completely abolish expression of the human surfactant protein B (hSP-B) 1.5 kb lacZ reporter gene in the lung in vivo. Acetylation of transcription factors by nuclear receptor coactivators is an important mechanism for gene regulation. TTF-1 is acetylated by nuclear receptor coactivators including the activator of the thyroid and retinoic acid receptor, CREB-binding protein, and steroid receptor coactivator 1 (SRC-1) in cell transfection and immunoprecipitation studies. A glutathionine transferase pull-down assay shows TTF-1 direct interaction with the SRC-1 histone acetyltransferase domain. Site-specific mutagenesis identifies that the lysine residue at position 182 in the TTF-1 HD is acetylated in respiratory epithelial cells. Mutation at this acetylation site shows a dominant negative effect on SP-B gene transcription. The study supports a concept that acetylation is an important mechanism for TTF-1 activity.

Acetylation↗
PubMed2004

Synergy between signal transducer and activator of transcription 3 and retinoic acid receptor-alpha in regulation of the surfactant protein B gene in the lung.

During respiratory cycles, airborne particles and pathogens are inhaled into the lung, which can cause cytokine production by respiratory macrophages and inflammatory responses. Secreted cytokines affect surfactant protein expression and homeostasis in the lung. In coculturing experiments in vitro, bronchoalveolar macrophages stimulated human surfactant protein B (hSP-B) gene transcription in primary alveolar type II epithelial cells in lipopolysaccharide-independent and -dependent ways. Neutralization by IL-6 antibody abolished lipopolysaccharide-dependent macrophage stimulation of hSP-B gene transcription. IL-6 treatment enhanced signal transducer and activator of transcription (Stat)3 phosphorylation at Y705 in alveolar type II epithelial cells and Clara cells in vivo. Biochemical analysis of functional domain swapping between Stat1 and Stat3 identified that the SH2 domain and the DNA binding domain are critical for Stat3 stimulation of hSP-B gene transcription. Glutathione-S-transferase pull-down study determined functional domains required for protein-protein interaction between Stat3 and retinoic acid receptor-alpha. Cotransfection of Stat3 and retinoic acid receptor-alpha into respiratory epithelial cells resulted in synergistic DNA binding and transcriptional activation on the hSP-B gene. To assess Stat3 physiological function, overexpression of a dominant negative Stat3 in respiratory epithelial cells in a doxycycline-controlled double transgenic mouse line caused pulmonary emphysema and increase of animal death during hyperoxia. Therefore, the IL-6/Stat3 signaling axis plays an important role in surfactant protein homeostasis and respiratory inflammation in the lung.

Animals↗
PubMed2004

Mie-scattering calculation.

The new Mie-scattering calculation is a robust and efficient algorithm used to compute light scattering from spheres. It calculates the ratio between Riccati-Bessel functions instead of the complicated logarithmic derivative. The Kapteyn inequality is used to estimate the number of significant digits of the calculated Riccati-Bessel functions and their ratio. This new algorithm is stable and accurate for both large and small particles. The implemented C++ code yields the same accurate results for both small and large particles compared with Wiscombe's MIEV0 code in double precision. Suggestions are provided for the porting of the MIEV0 code.

Journal Article↗
PubMed2004

Effects of point-spread function on calibration and radiometric accuracy of CCD camera.

The point-spread function (PSF) of a camera can seriously affect the accuracy of radiometric calibration and measurement. We found that the PSF can produce a 3.7% difference between the apparent measured radiance of two plaques of different sizes with the same illumination. This difference can be removed by deconvolution with the measured PSF. To determine the PSF, many images of a collimated beam from a He-Ne laser are averaged. Since our optical system is focused at infinity, it should focus this source to a single pixel. Although the measured PSF is very sharp, dropping 4 and 6 orders of magnitude and 8 and 100 pixels away from the point source, respectively, we show that the effect of the PSF as far as 100 pixels away cannot be ignored without introducing an appreciable error to the calibration. We believe that the PSF should be taken into account in all optical systems to obtain accurate radiometric measurements.

Journal Article↗
PubMed2004

Lysosomal acid lipase and atherosclerosis.

PURPOSE OF REVIEW: Atherosclerosis remains the leading cause of death in the developed countries. In addition to lipid-lowering drugs - statins, dietary control, and exercise, new approaches are needed for the treatment and prevention of atherosclerosis. This review will focus on the role(s) of lysosomal acid lipase and its use as an enzyme therapy to reduce atherosclerotic lesions in a mouse model and to examine the molecular basis supporting this novel strategy and its mechanism of effect. RECENT FINDINGS: Administration of human lysosomal acid lipase via tail vein into mice with atherosclerosis eliminates early aortic and coronary ostial lesions and reduces lesional size in advanced disease. The reduction of advanced lesional area is related to decreases in foamy macrophages, collagen positive areas, and necrotic areas. Compared with sham-treated mice, the human lysosomal acid lipase-treated mice also have reduced levels of plasma cholesteryl esters, and reduced levels of hepatic cholesterol and triglycerides. SUMMARY: These studies indicate that administrated lysosomal acid lipase affects the atherogenesis by at least two mechanisms: (1) direct targeting of lesional macrophages with resultant decreases in cholesteryl esters and triglyceride in the lysosomes of macrophages in the lesions; (2) systemic effects that mediate the liver to reduce the hepatic cholesteryl ester and triglyceride release, possibly leading to reduced production of VLDL and LDL.

Animals↗
PubMed2004

Alveolus formation: what have we learned from genetic studies?

The respiratory system has two basic functions: air exchange and pathogen clearance. The conducting airway and alveolar parenchyma are the basic structures to fulfill these functions during respiratory cycles. In humans, there are approximately 40 cell types in the lung that coordinately work together through various structural and signaling molecules. These molecules are vital for maintaining normal lung functions in response to environmental changes. Aberrant expression of these molecules can jeopardize human health and cause various pulmonary diseases. In this article, we will review some recent progress made in the pulmonary field, using genetic animal model systems to elucidate molecular mechanisms that are important for alveolar formation and lung diseases.

Animals↗
PubMed2004

Intraductal ultrasonography and endoscopic retrograde cholangiography in diagnosis of extrahepatic bile duct stones: a comparative study.

BACKGROUND: Intraductal ultrasonography (IDUS) is highly accurate in detection of extrahepatic bile duct stones. This study was to compare the accuracy of IDUS and endoscopic retrograde cholangiography (ERC) in the diagnosis of extrahepatic bile duct stones. METHODS: Thirty patients suspected of extrahepatic bile duct stones on B ultrasonography, CT, or MRI were enrolled for study. ERC was performed using a Fujinon duodenoscope (ED-410XT, ED-410Xu), then IDUS was done by inserting a Fujinon microprobe (PL2220-15) through the endoscopic biopsy channel to detect the extrahepatic bile duct. Finally stones in the extrahepatic bile duct were detected and extracted by endoscopic sphincterotomy (EST). RESULTS: Among the 30 patients, 26 were diagnosed as having cholelithiasis accurately through ERC. In one patient the stone detected by ERC was really floccule. Misdiagnosis happened in 2 patients with extrahepatic bile duct stones. So the overall accuracy and sensitivity of ERC in the diagnosis of extrahepatic bile duct stones were 86.7% (26/30) and 92.9% (26/28) respectively. In contrast, IDUS showed the results of diagnosis were in consistent with those of EST stone extraction. Its accuracy and sensitivity in the diagnosis of extrahepatic bile duct stones were 100% (30/30) and 100% (28/28) respectively. CONCLUSION: IDUS which is superior to ERC in diagnosing extrahepatic bile duct stones can avoid the visual error of ERC.

Adult↗
PubMed2004

[Immunosuppressive therapies in patients with Graves' ophthalmopathy].

OBJECTIVE: To compare the efficacy and tolerability of 4 immunosuppressants in treating Graves' ophthalmopathy (GO). METHODS: Seventy-five untreated GO patients were enrolled in this study. The diagnosis of GO was based on the presence of the typical clinical features and exclusion of possible cranial/orbital diseases. In group A, 31 patients were randomly assigned to receive either prednisone (n = 16, treatment completed in 13 cases with doses of 40 mg, 20 mg and 10 mg per day for 4 weeks) or tripterygium wilfordii multiglycoside (TW, n = 15, 30 - 60 mg per day); in group B, 23 adults were randomized to receive cyclosporin A (CsA, n = 11, 5 - 6 mg per kilogram of body weight per day) or mycophenolate mofetil (MMF, n = 12, 16 - 18 mg per kilogram of body weight per day) therapy. The remaining 21 patients (control group) were given only anti-thyroid drugs and levo-thyroxine. The disease severity and therapeutic response were quantitatively assessed according to the Ophthalmopathy Index Scoring System from Given-Wilson (1989) with sensible modification. Improvement or progression of ophthalmopathy was defined if the difference, either increase or decrease, of the score, reached 3 or more in the ophthalmopathy index. If this did not occur, a lack of response was indicated. RESULTS: After 12 weeks, 7 of the 13 treated with prednisone improved and the remaining 6 lacked response. In the TW group, 10 of the 15 responded to the therapy; 5 had no change. There was no significant difference in clinical response between the above 2 groups (P > 0.05). Five CsA-treated and 11 MMF-treated patients responded to the therapy (45% vs 92%; P < 0.05). It seems that MMF is more effective than CsA in the treatment of GO, although a significant decrease (P < 0.01) in the mean score of the CsA group has also been shown at the end of the course. Four of the controls improved, 5 (24%) showed worsening of ophthalmopathy, and the remaining 12 (57%) had no significant change. In the prednisone group, 3 gained body weight by more than 5%, and 2 developed impaired glucose tolerance. These two and one of the three weight gaining patients ceased the therapy. CONCLUSIONS: New immunosuppressant MMF may be more effective than CsA in the treatment of Graves' ophthalmopathy. TW may be equally effective as and perhaps better tolerable than prednisone in the immunotherapy of Graves' ophthalmopathy.

Adult↗
PubMed2004

[Genotyping of HBV DNA in Shenzhen and clinical manifestations].

OBJECTIVE: To detect HBV DNA and its genotypes. METHODS: The 6 isoforms of HBV DNA was detected out using of different probes by Polymerase Chain Reaction and Nucleic Acid hybridization. RESULTS: Of 150 HBV DNA positive patients who lived in Shenzhen, 50 samples (33%) are type B, 36 samples (24%) are type C, 13 samples (9%) are type D, 3 samples is type F, 1 sample is type A, 48 samples (31%) are mixed type. The ALT value was significantly higher in genotype B than in genotype C. HBe positivity were higher in genotype B than genotype C. HBeAg positivity were higher in genotype C than in genotype B. There are not obvious relations between genotype and age or sex. CONCLUSION: In the detected samples, the major genotype of HBV DNA is type B, several are type C, D. The type E haven't been found. There are some relations between all kinds of genotypes and the severity of hepatitis B.

Adult↗
PubMed2004

[Analysis of the relative etiology of non-obstructive azoospermia].

OBJECTIVE: To investigate the levels and changes of sexual hormone in serum and seminal plasma, and the epidermal growth factor (EGF), alpha-glucosidase, and fructose in the seminal plasma of non-obstructive azoospermic patients, and to assess the significance of the analysis of their chromosomes. METHODS: Thirty-six non-obstructive azoospermic males and 26 normal males were chosen. The results in reproductive endocrine and genetics obtained by radioimmunoassay, colorimetry, and chromosomes G and C banding assay were compared and analyzed to explore into the causes of infertility. RESULTS: The levels of FSH, LH, PRL and E2 in the serum of the non-obstructive azoospermic patients were higher than those of the control group, but the T level had no significant difference between the two groups. There were no obvious differences in the sexual hormones except in FSH of the seminal plasma. There were 2 cases of abnormal sex chromosomes, 2 cases of big Y chromosomes and 7 cases of small Y chromosomes in the non-obstructive azoospermic patients. No correlation was found between EGF and fructose in the seminal plasma. CONCLUSION: The level of sexual hormone in serum, alpha-glucosidase in seminal plasma and abnormal chromosomes might be closely related to non-obstructive azoospermia.

Adult↗
PubMed2004

[Krypton laser photocoagulation at low power setting for age-related macular degeneration complicated with subfoveal choroidal neovascularization].

OBJECTIVE: To evaluate the efficacy of krypton laser photocoagulation for treatment of age-related macular degeneration (AMD) complicated with mainly subfoveal classic choroidal neovascularization (CNV). METHODS: Seventeen eyes of 17 cases, aged 50 - 74 years (averaged 60.8 years) with mainly subfoveal classic choroidal neovascularization were treated with krypton laser at lower power setting. The treatment was completed in one session. Another course of treatment was given 4 weeks later if there was active leakage demonstrated at the CNV area. Visual acuity, anterior segment and fundus examination, perimetry test, fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA) were performed before and after treatment. The follow-up period was 3.5 years on average (1 - 8 years). RESULTS: There was no immediately decrease of visual acuity after treatment. All treated eyes showed absorption of hemorrhages and/or exudates and diminished leakages. Visual acuity was stable in 8 eyes; improved in 6 eyes (>/= 2 lines), and decreased in 3 eyes (</= 2 lines). The central scotoma showed no significant changes after the treatment. Closure of CNV was confirmed on FFA/ICGA and no recurrence was found in 9 cases during 3 years follow-up. CONCLUSION: Krypton laser photocoagulation at low power setting is an effective treatment for AMD with mainly classic subfoveal choroidal neovascularization.

Aged↗
PubMed2003

Lysosomal acid lipase deficiency causes respiratory inflammation and destruction in the lung.

The functional roles of neutral lipids are poorly understood in the lung. Blocking cholesteryl ester and triglyceride metabolism in lysosomal acid lipase gene knockout mice (lal-/-) resulted in a high level of neutrophil influx in the lungs as early as 2 mo of age. Bronchoalveolar macrophages appeared foamy and gradually increased in number with age progression. Affymetrix GeneChip array analysis of lung mRNA showed increased levels of proinflammatory cytokine (including IL-1beta, IL-6, and TNF-alpha) and matrix metalloproteinase (including MMP-8, MMP-9, and MMP-12) expression in lal-/- mice. With age progression, some areas of lal-/- mice developed severe abnormal cell proliferation and alveolar remodeling. In other areas, alveolar destruction (i.e., emphysema) was observed. In addition, Clara cell hypertrophy and hyperplasia developed in conducting airways. The pathophysiological phenotypes in the lal-/- mouse lungs became more severe with increasing age. The studies support the concept that neutral lipid metabolites play essential roles in pulmonary homeostasis, inflammatory responses, remodeling, and injury repair.

Animals↗
PubMed2003

Reduction of atherosclerotic plaques by lysosomal acid lipase supplementation.

OBJECTIVE: Proof of principle is presented for targeted enzyme supplementation by using lysosomal acid lipase to decrease aortic and coronary wall lipid accumulation in a mouse model of atherosclerosis. METHODS AND RESULTS: Mice with LDL receptor deficiency were placed on an atherogenic diet and developed predictable aortic and coronary atheroma. alpha-Mannosyl-terminated human lysosomal acid lipase (phLAL) was produced in Pichia pastoris, purified, and administered intravenously to such mice with either early or late lesions. phLAL injections reduced plasma, hepatic, and splenic cholesteryl esters and triglycerides in affected mice. phLAL was detected in hepatic Kupffer cells and in atheromatous foam cells. Repeated enzyme injections were well tolerated, with no obvious adverse effects. In addition, the coronary and aortic atheromatous lesions were (1) eliminated in their early stages and (2) quantitatively and qualitatively reduced in their advanced stages. CONCLUSIONS: These results support the potential utility of lysosomal acid lipase supplementation for the treatment of atherosclerosis, a leading cause of mortality and morbidity in Westernized nations.

Animals↗
PubMed2003

Peroxisome proliferator-activated receptor gamma and ligands inhibit surfactant protein B gene expression in the lung.

Pulmonary nonciliated bronchiolar epithelial cells (Clara cells) and alveolar type II (AT II) epithelial cells are responsible for surfactant synthesis and secretion. These cells are highly lipogenic with a high lipid turnover rate. Although only 10% of surfactant lipids are neutral lipids, they play very important roles in maintaining pulmonary surfactant homeostasis. Many metabolic intermediate products of neutral lipids serve as ligands for various nuclear receptors that bind to target genes to influence gene transcription. In this report, the functional role of the neutral lipid metabolites, 15-deoxy-Delta12,14-prostaglandin J2 and 9-hydroxyoctadecanoic acids, and peroxisome proliferator-activated receptor gamma was evaluated in surfactant protein B gene regulation. These reagents down-regulated surfactant protein B gene expression in respiratory epithelial cells at the transcriptional level in both cell line and whole lung explant systems. The studies support the concept that surfactant protein B homeostasis is influenced by neutral lipid metabolites in the lung.

Animals↗
PubMed2003

Lysosomal enzymes are released from cultured human macrophages, hydrolyze LDL in vitro, and are present extracellularly in human atherosclerotic lesions.

OBJECTIVE: Human atherosclerotic lesions have been shown to contain lipid droplets and vesicles resembling those of in vitro enzymatically modified LDL. However, little is known about the hydrolytic enzymes in the arterial intima that induce fusion of LDL particles and so produce lipid droplets or that induce foam cell formation. METHODS AND RESULTS: Human coronary atherosclerotic lesions obtained at surgery and at autopsy were stained for lysosomal acid lipase and cathepsin D. The extracellular areas of macrophage-rich intimal regions of the atherosclerotic lesions stained positively for both cathepsin D and lysosomal acid lipase, whereas normal arteries were negative. When monocyte-derived macrophages were incubated with opsonized zymosan to stimulate the release of lysosomal enzymes from the cells and LDL was incubated with the macrophage-conditioned media, the apolipoprotein B-100, cholesteryl esters, and triacylglycerols of LDL were hydrolyzed. These hydrolytic modifications rendered the LDL particles unstable and induced their fusion. Cultured macrophages and smooth muscle cells took up the hydrolase-modified LDL particles avidly and were transformed into foam cells. CONCLUSIONS: Our in vivo and in vitro results suggest that lysosomal enzymes released from macrophages may induce hydrolytic modification of LDL and foam cell formation in the human arterial intima.

Apolipoprotein B-100↗