Biomedical subjects
Publications and source records attributed to Hong Liang.
A new triterpenoid saponin, julibroside J(28) (1), was isolated from the stem bark of Albizia julibrissin Durazz (Leguminosae) by using chromatographic method. The structure of 1 was established by spectroscopic methods. 1 displayed significant antitumor activity in vitro against PC-3M-1E8, Bel-7402, and HeLa cancer cell lines at 10 microM assayed by SRB method.
Acquired complete and partial deletions of chromosome 7 are associated with several malignancies. In acute myelogenous leukemia (AML) and preleukemic myelodysplasia (MDS), loss of chromosome 7 portends a poor clinical outcome. The identity of a classical leukemia suppressor gene, however, has been elusive. Previously, we defined a candidate suppressor locus of approximately 6 Mb in the 7q31 interval. Here we report an island of retention of heterozygosity within this interval in a case of monosomy 7. Allelotyping of AML cell lines revealed that ML3 and HEL cells, karyotypically diploid for chromosome 7, are hemizygous for all the 7q31 loci, implicating loss of the wild type and duplication of the remaining chromosome 7. Based on the completed genomic sequence of chromosome 7, we have generated a transcript map of the critical region of loss (between the D7S525 and D7S2502 loci). Notably, a recently characterized tumor suppressor gene, DOCK4, and an evolutionarily conserved zinc finger gene, ZNF277, localize to this interval, head to head, within <0.5 kb of each other. Thus, the reagents generated in this study will be valuable in elucidating the role of loss of 7q31 loci in the pathogenesis of AML.
The structures of four new diastereoisomeric triterpenoidal saponins Julibroside J5, J8, J12 and J13 (1-4) isolated from Albizia julibrissin Durazz. (Leguminosae) have been determined on the basis of comprehensive spectroscopic analysis and chemical degradation. Julibroside, J8 and J13 showed marked cytotoxic activities against Bel-7402 cancer cell line at 100 microg/mL.
Acute myelogenous leukemia (AML) is the most common leukemia in adults with clonal proliferation of myeloid stem cells. Two or more cooperating mechanisms, namely block in differentiation, enhanced proliferation and resistance to programmed cell death, underlie this neoplastic transformation. Nonrandom, complete and partial deletions of chromosome 5 are common anomalies in AML. Using positional cloning strategies, we characterized an evolutionarily conserved candidate myeloid leukemia suppressor gene encoding sequence-specific single-stranded DNA binding protein 2 (SSBP2) from chromosome 5q13.3, a locus that is frequently deleted in AML. Recent studies in Drosophila and Xenopus demonstrate a pivotal role for SSBPs in embryonic differentiation. In mammals, SSBP2 is one of three highly related and ubiquitously expressed genes. Here, we identify frequent loss of SSBP2 protein expression in human AML cell lines using highly specific antibodies. Furthermore, inducible expression of SSBP2 in the AML cell line U937 leads to loss of clonogenicity, G1 arrest and partial differentiation. Remarkably, inducible expression of SSBP2 is accompanied by downregulation of C-MYC expression. Our findings are consistent with human SSBP2 being a novel regulator of hematopoietic growth and differentiation, whose loss confers a block in differentiation advantage to myeloid leukemic cells.
BACKGROUND: Accurate inflammatory mechanisms in chronic ocular surface diseases (OSDs) cannot routinely be assessed. New techniques for investigating ocular surface inflammatory pathways are of major importance. OBJECTIVE: To investigate the expressions of CCR 4 and CCR 5, known to be related to the T(H)2 and T(H)1 systems, respectively, and HLA-DR in conjunctival impression cytology specimens from patients with chronic OSDs. METHODS: In this case-controlled study, impression cytology specimens were taken in a series of patients with vernal keratoconjunctivitis (n=21), giant papillary conjunctivitis (n=6), or keratoconjunctivitis sicca (KCS; n=17), or receiving topical antiglaucoma treatments (n=31), and from 20 normal subjects. Conjunctival cells were incubated with mAbs to CCR 4, CCR 5, CD45, and HLA-DR to quantify conjunctival inflammation in a masked manner using flow cytometry. RESULTS: HLA-DR was higher in the glaucoma and KCS groups than in allergic and normal eyes. CCR 4 was overexpressed in allergy and glaucoma, whereas CCR 5 was higher in the KCS and glaucomatous groups. CD45 was expressed by only few cells in all groups, with almost no significant differences. CCR 4 expression was negatively correlated with CCR 5 and HLA-DR, whereas CCR 5 was positively correlated with HLA-DR. CONCLUSION: This study confirms the overexpression of chemokine receptors by the conjunctival epithelium in OSDs. CCR 4 and CCR 5 expression may vary according to the immune pathway involved. Accurate mechanisms in ocular surface inflammatory reactions-that is, those related to the T(H)1 or T(H)2 systems-could be differentiated by CCR 4/CCR 5 profiles. Our results also suggest that long-term use of topical treatments may stimulate both systems.
OBJECTIVE: We analyzed the factors influencing the cardiac function of patients after weaning from ventricular assist devices and established a prognostic index. METHOD: A multivariate analysis was performed using the Cox proportional hazards model of the clinical parameters of 28 patients with end-stage heart failure before implantation of a ventricular assist device and directly before weaning from the device. RESULTS: After weaning from the ventricular assist devices, 14 of the 28 investigated patients showed stable cardiac function, and 12 had recurrent heart failure, but only 1 of them died before transplantation or implantation of another ventricular assist device, and 2 patients died of causes unrelated to heart failure. In addition to left ventricular ejection fraction, the duration of symptomatic heart failure and left ventricular intracavitary dimensions in diastole measured before ventricular assist devices weaning were the major factors influencing cardiac function after weaning. In the group of patients with heart failure duration less than 3 years, only 2 of 13 cases were recurrent, but in the group with heart failure duration more than 3 years, 10 of 15 cases were recurrent. In 10 patients with 40 to 50 mm left ventricular intracavitary dimensions in diastole before weaning, only 1 case was recurrent. In 10 patients with 51 to 55 mm left ventricular intracavitary dimensions in diastole, 3 cases were recurrent. In the group with left ventricular intracavitary dimensions in diastole more than 56 mm, all 8 cases were recurrent. A prognostic index was calculated using the following formula: prognostic index = -10.10 + 0.208 (heart failure duration in years) + 0.173 (pre-explantation left ventricular intracavitary dimensions in diastole in millimeters). In the group with a prognostic index less than 0, only 2 of 16 cases were recurrent, and the rate of stable cardiac function in the 51st month after weaning was 83.6%. In the group with a prognostic index greater than 0, 10 of 12 cases were recurrent, and the rate of stable function in the 57th month was 0.0%. CONCLUSION: In patients with off-pump left ventricular ejection fraction greater than 40%, the duration of symptomatic heart failure and the left ventricular intracavitary dimensions in diastole measured before weaning yield a useful index to predict long-term cardiac function after weaning from ventricular assist devices.
Apoptosis is a major cell death mechanism that occurs widely in normal tissues and is overstimulated in ocular surface diseases. Apoptosis has been studied specifically in regard to refractive surgery, contact lens wear, and dry eye syndrome. It appears to be closely related to inflammation, as many inflammatory cytokines may promote both inflammation and apoptosis, and their receptors trigger both pathways. A major mediator would play a key role in ocular surface diseases, both at the pro-apoptotic and pro-inflammatory levels, e.g., tumor necrosis factor alpha. This cytokine and its main receptors are, therefore, overexpressed in ocular surface diseases, which makes it a possible target for future therapeutic approaches.
From the stems of Millettia nitida var. hirsutissima, three new isoflavone glycosides, formononetin 7-O-beta-D-(6''-ethylmalonyl)-glucopyranoside (1, hirsutissimiside A), 5-O-methyl genistein 7-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (3, hirsutissimiside B), retusin 7,8-di-O-beta-D-glucopyranoside (4, hirsutissimiside C) and two known isoflavone glycosides (2) and (5) have been isolated. The structures of the compounds were determined by spectroscopic and chemical means.
OBJECTIVE: To study the chemical constituents of Acanthus ilicifolius. METHOD: Chromatographic methods were used to isolate compounds from A. ilicifolius, and chemical and spectral methods were used to elucidate the structures of the isolated compounds. RESULT: Five compounds, luteolin 7-O-beta-D-glucuronide (1), apigenin-7-O-beta-D-glucuronide (2), methylapigenin-7-O-beta-D-glucuronate (3), uridine (4) and uracil (5) were obtained. CONCLUSION: 1, 4 and 5 were obtained from the genus for the first time.
Rutin is one of the natural flavonoids in plants. Effects of rutin and indoleacetic acid (IAA) on vegetative growth of mung bean seedlings were studied and the contents of rutin and IAA in the hypocotyls of the seedlings were measured. Mung bean seedlings absorbed rutin through roots, grew more vigorously under light at lower rutin concentrations (20-60 microg/mL) with longer shoot axis (epicotyl+hypocotyl) and primary root and more lateral roots. The seedlings exhibited inhibition of elongation of the hypocotyls and radicles when grown in the dark at rutin concentrations of 20-100 microg/mL or under light at rutin concentrations of 80-100 microg/mL. Seedlings under light absorbed more rutin than those in the dark at rutin concentrations of 60-80 microg/mL and absorbed less rutin at concentrations lower than 40 microg/mL or near 100 microg/mL. IAA (>0.1 microg/mL) treatment promoted rutin accumulation and inhibited elongation of shoot axis and primary roots. The rutin content in hypocotyls reached the highest level when IAA (0.5 microg/mL) and rutin (40 microg/mL) were added to the medium. Rutin repressed endogenous IAA accumulation in hypocotyls of the etiolated seedlings and inhibited absorption of exogenous IAA from media to seedlings.
OBJECTIVE: To investigate the chemical constituents of Potentilla multifida. METHOD: Various chromatographic techniques were employed for isolation and purification of the constituents. The structures were elucidated by spectral analysis. RESULT: Four megastigmane glycosides were isolated from P. multifida and their structures were identified as citroside A (1), icariside B1 (2), (6S,7E,9R)-roseoside (3), (6S,7E,9R)-vomifoliol-9-O-beta-D-xylopyranosyl-(1-->6)-O-beta-D-glucopyranoside (4), respectively. CONCLUSION: All compounds were obtained from the genus Potentilla for the first time.
The interaction of nicotine and bovine serum albumin(BSA) was investigated by fluorescence spectra and UV-vis spectra. The fluorescence spectrum showed that BSA fluorescence quench regularly with the addition of nicotine.The fluorescence quenching mechanisms were also studied in pH 5.0, pH 7.4 and pH 11.0 by Stern-Volmer equation, indicating dynamic quenching(pH 5.0) and static quenching(pH 7.4 and pH 11.0) respectively. Association constants (k) of nicotine and BSA at pH 7.4 and pH 11.0 at the temperatures of 20 and 37 degrees C were given by the Lineweaver-Buck equation, which are: k(20 degrees C) = 140.15 L x mol(-1) and k(37 degrees C) = 131.83 mol x L(-1) (pH 7.4), and k(20 degrees C) = 141.76 mol x L(-1), k(37 degrees C) = 27.79 mol x L(-1) (pH 11.0), suggesting that the association constant is effected by the temperature much more remarkably at pH 7.4 than that at pH 11.0 because of the different states of nicotine at different pHs. The UV-Vis spectra exhibit that the absorbance of BSA(210 nm) shifts to red and decreases gradually with the addition of nicotine, reflecting the transition of secondary structure of BSA, namely, the helix of BSA becomes looser. The UV-Vis second derivative spectra and synchronous spectra (delta wavelength = wavelength(em) - wavelength(ex) = 15 nm and delta wavelength = wavelength(em) - wavelength(ex) = 60 nm) imply the change of the microcircumstance of aromatic amino residues of BSA(Trp, Tyr and Phe) from hydrophobicity to hydrophilicity at high concentration of nicotine.
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We studied the effect of intrauterine food restriction (FR) on the immune function, endocrine status and attractiveness of scents of male rat-like hamsters, Cricetulus triton. Work was conducted on field-caught parents from the North China plain and their laboratory-born progeny. Restricted pregnant dams were fed 70% of the mean daily intake of hamsters with free access to food. FR caused a marked and protracted weight reduction of the body, adrenal, testes and epididymides in males. During the refeeding period, the spleen and thymus, but not the adrenal weight of the malnourished offspring caught up with that of the control after about 60 days. The present results demonstrated that estrous females preferred the odors of control males to that of FR males. Males whose mothers were food restricted during gestation had lower testosterone concentrations, immune responses and reproductive organ mass but had higher circulating cortisol than did the males in the control group. Thus, the effect of maternal FR may be an important cause in population regulation in the rat-like hamster. The testosterone level was positively correlated with immune function in rat-like hamsters, but the lower immunity was not suppressed by higher level of testosterone, as previously suggested. We also found a negative relationship between cortisol and immune function in the rat-like hamster.
The triggering Ag for inflammatory bowel disease and animal models of colitis is not known, but may include gut flora. Feeding OVA to DO11.10 mice with OVA-specific transgenic (Tg) TCR generates Ag-specific immunoregulatory CD4(+) T cells (Treg) cells. We examined the ability of oral Ag-induced Treg cells to suppress T cell-mediated colitis in mice. SCID-bg mice given DO11.10 CD4(+)CD45RB(high) T cells developed colitis, and cotransferring DO11.10 CD45RB(low)CD4(+) T cells prevented CD4(+)CD45RB(high) T cell-induced colitis in the absence of OVA. The induction and prevention of disease by DO11.10 CD4(+) T cell subsets were associated with an increase in endogenous TCRalpha chain expression on Tg T cells. Feeding OVA to SCID-bg mice reconstituted with DO11.10 CD4(+)CD45RB(high) attenuated the colitis in association with increased TGF-beta and IL-10 secretion, and decreased proliferative responses to both OVA and cecal bacteria Ag. OVA feeding also attenuated colitis in SCID-bg mice reconstituted with a mix of BALB/c and DO11.10 CD45RB(high) T cells, suggesting that OVA-induced Treg cells suppressed BALB/c effector cells. The expression of endogenous non-Tg TCR allowed for DO11.10-derived T cells to respond to enteric flora Ag. Furthermore, feeding OVA-induced Treg cells prevented colitis by inducing tolerance in both OVA-reactive and non-OVA-reactive T cells and by inducing Ag-nonspecific Treg cells. Such a mechanism might allow for Ag-nonspecific modulation of intestinal inflammation in inflammatory bowel disease.
Clinically relevant peripheral neuropathies (such as diabetic and human immunodeficiency virus sensory neuropathies) are characterized by distal axonal degeneration, rather than neuronal death. Here, we describe a novel, endogenous pathway that prevents axonal degeneration. We show that in response to axonal injury, periaxonal Schwann cells release erythropoietin (EPO), which via EPO receptor binding on neurons, prevents axonal degeneration. We demonstrate that the relevant axonal injury signal that stimulates EPO production from surrounding glial cells is nitric oxide. In addition, we show that this endogenous pathway can be therapeutically exploited by administering exogenous EPO. In an animal model of distal axonopathy, systemic EPO administration prevents axonal degeneration, and this is associated with a reduction in limb weakness and neuropathic pain behavior. Our in vivo and in vitro data suggest that EPO prevents axonal degeneration and therefore may be therapeutically useful in a wide variety of human neurological diseases characterized by axonopathy.
BACKGROUND: Dendritic cells are important antigen-presenting cells. After an allergen inhalation, their numbers rapidly decrease in circulation and increase in the airway mucosa. OBJECTIVE: To investigate whether allergen-induced changes in the number of circulating dendritic cells are mediated by cysteinyl leukotrienes. METHODS: In a randomized, double-blind, crossover study, we examined the effects of 2 weeks of treatment with pranlukast (a cysteinyl leukotriene 1 [CysLT1] receptor antagonist) 300 mg twice daily and placebo on allergen-induced changes in airway responses and circulating dendritic cells in 15 subjects with mild asthma. We examined by flow cytometry, before and at 3 hours and 24 hours after allergen inhalation, the proportion of myeloid (CD33+) and plasmacytoid (CD123+) dendritic cells (HLA-DR+, CD14-, CD16-) among all peripheral blood mononuclear cells. The fraction of dendritic cells expressing CysLT1 receptor was also determined. RESULTS: Compared with placebo, pranlukast significantly attenuated both the maximum early (by 55%) and the late (by 39%) asthma responses, the allergen-induced methacholine airway hyperresponsiveness, and the increase in macrophage inflammatory protein 1alpha and 3alpha in induced sputum. A significantly greater proportion of CD33+ cells (55%) expressed CysLT1 receptor compared with CD123+ cells (11%). Consistent with this, pranlukast prevented the allergen-induced decrease in CD33+ dendritic cells at 3 hours postallergen (mean Delta from baseline, +4.4%) compared with placebo (mean Delta, -8.4; P <.05), but not CD123+ cells. CONCLUSION: Pretreatment with pranlukast attenuated allergen-induced airway responses and the decrease in circulating myeloid dendritic cells, demonstrating a novel role of cysteinyl leukotrienes in dendritic cell trafficking.
PURPOSE: To compare the conjunctival epithelial cell expressions of inflammatory cytokines in normal subjects and in glaucoma patients treated over the long term. DESIGN: Case-control study. PARTICIPANTS: A total of 69 glaucoma patients treated over the long term and 15 normal subjects with no ocular abnormality or topical treatment. METHODS: Amongst the 69 glaucoma patients, 27 were treated with preserved beta-blockers, 24 with unpreserved 0.5% timolol, and the other 18 patients with an association of > or =2 preserved drugs. All patients were treated for more than 1 year with the same treatment, with no significant differences between groups for mean ages and durations of treatment at the time of the study. Impression cytology specimens were taken and processed for immunofluorescence techniques. Conjunctival cell expressions of HLA DR, as a standard for inflammatory level, and the interleukins IL-6, IL-8, and IL-10 were obtained and quantified using flow cytometry. MAIN OUTCOME MEASURES: Immune markers and proinflammatory cytokines in impression cytology specimens. RESULTS: We found a significantly increased expression of all immunoinflammatory markers and mediators in the conjunctival epithelium of glaucoma patients compared with normal eyes. Human leukocyte antigen DR was significantly higher in the 2 groups receiving preserved drugs than in the unpreserved timolol group. The 3 interleukins were similarly overexpressed in all glaucoma groups, with no significant between-groups differences except for the expression level of IL-8, which was significantly higher in the multitreatment group than in the preservative-free one. CONCLUSIONS: The present study confirms the increased expression of immunoinflammatory markers by the conjunctival epithelium of glaucoma patients treated over the long term. The development of nontoxic preservatives or preservative-free solutions is therefore of great interest.