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Biomedical subjects

Qing Li

Publications and source records attributed to Qing Li.

At least 163 records · Page 9Linked to original sources
PubMed2003

Chronic vulvar purpura: persistent pigmented purpuric dermatitis (lichen aureus) of the vulva or plasma cell (Zoon's) vulvitis?

BACKGROUND: Lichen aureus is localized variant of persistent pigmented purpuric dermatitis that typically affects the legs and can be associated with delayed hypersensitivity reactions or vascular abnormalities. Plasma cell vulvitis (Zoon's vulvitis) is a rare condition that frequently contains hemosiderin deposits and is suspected to be a mucosal reaction pattern due to variety of insults, most often local irritation or trauma. CASE REPORT: A 50-year-old female with longstanding complaints of spotting, vulvar dryness, irritation, and dyspareunia presented with circumscribed, purpuric, erythematous vulvar patches. Past estrogen cream treatment evoked symptoms of discomfort. On biopsy, siderophages and extravasated red blood cells were found in conjunction with a lichenoid, lymphocyte and plasma cell infiltrate, and dilated dermal and intraepithelial vessels. CONCLUSIONS: Reported herein is an unusual vulvar dermatosis that is best classified as a localized variant of persistent pigmented dermatosis (lichen aureus) but overlaps clinically and histologically with Zoon's vulvitis. This constellation of findings may represent a site-specific mucosal reaction to an erosive process that could either be inflammatory (hypersensitivity reaction) and/or traumatic in nature.

Chronic Disease↗
PubMed2003

Transgenic expression of a putative calcium transporter affects the time of Arabidopsis flowering.

PPF1 is a gibberellin-induced, vegetative growth-specific gene, first isolated from short-day (SD)-grown G2 pea plants. In the current work, we found that transgenic Arabidopsis plants overexpressing the PPF1 gene (PPF1 (+)) flowered much later and had a significantly longer lifespan compared to control plants, whereas suppression of this gene (PPF1 (-)) resulted in a very rapid reproductive cycle. Western blotting analyses of PPF1 (+) and (-) plant lines revealed a positive correlation between the amount of antibody-reactive protein and the time of flowering. Green fluorescent protein (GFP) co-expression assays showed that the PPF1 protein is likely localized in chloroplast membranes. Transgenic expression of PPF1 affected the calcium storage capacities since chloroplasts isolated from PPF1 (+) plants contained high Ca2+ levels while chloroplasts of PPF1 (-) plants contained very low amounts of calcium ion. Using Novikoff human hepatoma cells, we demonstrated that expression of PPF1 leads to a significant inward calcium ion current that was absent in untransformed cells. We conclude that, as a putative calcium ion carrier, PPF1 affects the flowering time of higher plants by modulating Ca2+ storage capacity within chloroplasts.

Arabidopsis↗
PubMed2003

Placenta previa: neonatal death after live births in the United States.

OBJECTIVE: The purpose of this study was to describe neonatal mortality rates among live births that were complicated by placenta previa in the United States. STUDY DESIGN: This was a population-based retrospective cohort study of 1997 United States singleton live births. Neonatal deaths among pregnancies that were complicated by placenta previa were compared with deaths among pregnancies with no placenta previa. Adjusted and unadjusted hazard ratios were generated from a proportional hazards regression model. RESULTS: Of 3,773,369 live births, 9656 were complicated by placenta previa (2.6 cases per 1000). Among cases of placenta previa, 114 neonatal deaths occurred (11.8 per 1000) versus 14951 (4 per 1000) among non-placenta previa neonates (P <.0001). The adjusted relative risk of death was three times higher among placenta previa neonates (hazard ratio, 3.06; 95% CI, 2.40-3.94). Placenta previa-related death was mediated through preterm delivery rather than small for gestational age. CONCLUSION: Placenta previa triples the rate of neonatal mortality, which is mediated mainly through preterm birth.

Adult↗
PubMed2003

Expression of a conserved mouse stress-modulating gene, Bre: comparison with the human ortholog.

Mouse Bre, an evolutionarily conserved stress-modulating gene, like its human counterpart, is expressed in multiple alternative transcripts. The main transcript, which is ubiquitously expressed, encodes a protein that binds tumor necrosis factor receptor 1 (TNF-R1) and downregulates TNF-induced activation of NF-kappaB. Alternative splicing of mouse Bre occurs only at the 5' region of the gene, generating either nonfunctional transcripts or transcripts that can encode putative protein isoforms differ at the N-terminal sequence. In contrast, alternative splicing of human BRE occurs at either or both ends of the gene; only the 3' alternative splicing can generate functional transcripts that encode putative protein isoforms differ at the C-terminus, occurrence of the 5' alternative splicing only results in forming nonfunctional transcripts. Unlike the human BRE alternative transcripts which are coexpressed at considerable levels with the main transcript, the mouse counterparts are expressed in a restricted pattern and generally in low abundance except in the heart. Both species, however, share a type of Bre alternative transcripts generated by cryptic splicing at a nonstandard, noncanonical acceptor site. Thus, a highly conserved gene in two species can generate alternative transcripts different in both of the sequence structure and expression pattern, as well as a similar class of transcripts resulting from unconventional transcript processing.

Alternative Splicing↗
PubMed2003

Do local opinion leaders augment hospital quality improvement efforts? A randomized trial to promote adherence to unstable angina guidelines.

BACKGROUND: The influence of an opinion leader intervention on adherence to Unstable Angina (UA) guidelines compared with a traditional quality improvement model was investigated. RESEARCH DESIGN: A group-randomized controlled trial with 2210 patients from 21 hospitals was designed. There were three intervention arms: (1) no intervention (NI); (2) a traditional Health Care Quality Improvement Program (HCQIP); and (3) a physician opinion leader in addition to the HCQIP model (OL). Quality indicators included: electrocardiogram within 20 minutes, antiplatelet therapy within 24 hours and at discharge, and heparin and beta-blockers during hospitalization. Hospitals could determine the specific indicators they wished to target. Potential cases of UA were identified from Medicare claims data. UA confirmation was determined by a clinical algorithm based on data abstracted from medical records. Data analyses included both hospital level analysis (analysis of variance) and patient level analysis (generalized linear models). RESULTS: The only statistically significant postintervention difference in percentage compliant was greater improvement for the OL group in the use of antiplatelet therapy at 24 hours in both hospital level (P = 0.01) and patient level analyses (P <0.05) compared with the HCQIP and NI groups. When analyses were confined to hospitals that targeted specific indicators, compared with the HCQIP hospitals, the OL hospitals showed significantly greater change in percentage compliant postintervention in both antiplatelet therapy during the first 24 hours (20.2% vs. -3.9%, P = 0.02) and heparin (31.0% vs.9.1%, P = 0.05). CONCLUSIONS: The influence of physician opinion leaders was unequivocally positive for only one of five quality indicators. To maximize adherence to best practices through physician opinion leaders, more research on how these physicians influence health care delivery in their organizations will be required.

Aged↗
PubMed2003

Racial differences in thoracic aorta atherosclerosis among ischemic stroke patients.

BACKGROUND AND PURPOSE: Atherosclerosis of the thoracic aorta is an independent risk factor for stroke. There is little information on the impact of race in the prevalence of thoracic aorta atherosclerotic plaques among ischemic stroke patients. This study was an attempt to objectively assess the prevalence, thickness, and burden of thoracic aorta atherosclerotic plaques in a large population of ischemic stroke patients and to compare the differences between American blacks and whites. METHODS: This is a retrospective study of clinical data and transesophageal echocardiography (TEE) of 1553 ischemic stroke patients (664 blacks, 889 whites) over a period of 4.5 years. Atherosclerotic plaque prevalence, thickness, morphology, and burden (sum of maximum thickness in ascending aorta [AA], aortic arch [AO], and descending aorta [DA]) were assessed with TEE. Charts were reviewed for clinical information. RESULTS: Age and sex were similar among blacks and whites. Analyses of clinical data found that blacks had significantly higher hypertension (odds ratio [OR], 2.61; P<0.0001) and diabetes mellitus (OR, 1.99; P<0.0001) and significantly lower coronary artery disease (OR, 0.75; P=0.017) and carotid artery disease (OR, 0.62; P=0.0008) compared with whites. TEE showed that whites had significantly greater plaque prevalence (AA: OR, 1.37; P=0.04; AO: OR, 1.26; P=0.03; DA: OR, 1.39; P=0.002) and plaque burden (blacks, 4.28 mm; whites, 4.97 mm; P=0.007). Whites also had a trend of increased complex plaques and plaques >4 mm thick in all regions of the thoracic aorta. CONCLUSIONS: Among ischemic stroke patients, blacks had a lower prevalence of extra cranial atherosclerotic disease even though they had significantly higher hypertension and diabetes mellitus compared with whites. This difference cannot be explained by the existing risk factors in ischemic stroke patients.

Adult↗
PubMed2003

Recruitment of antigen-specific Th1-like responses to the human lung following bronchoscopic segmental challenge with purified protein derivative of Mycobacterium tuberculosis.

Although the mechanisms of specific immunity to Mycobacterium tuberculosis in humans are poorly understood, responses of Th1-like CD4+ T cells appear to be essential for protection. We hypothesized that healthy individuals displaying positive skin-test responses to purified protein derivative of M. tuberculosis (PPD) would have the capacity to mobilize M. tuberculosis-specific Th1 cells to the lung in response to bronchoscopic challenge with PPD. Local instillation of 0.5 tuberculin units of PPD was followed 48 h subsequently by bronchoalveolar lavage (BAL) of PPD-challenged and control segments. In PPD-positive subjects, PPD challenge resulted in a 2.7-fold increase in total BAL cells and in an increase in the percentage of lymphocytes in BAL from 10 to 19%. The BAL lymphocytosis observed in PPD-challenged segments was characterized by an increased percentage of CD4+ T cells and by increased numbers of cells capable of antigen-specific interferon-gamma production. In contrast, PPD-negative subjects did not develop local inflammation following PPD challenge. These findings indicate that bronchoscopic challenge with PPD results in recruitment of antigen-specific recall responses to the lung. This novel approach may be useful in clarifying the basis of local immunity against M. tuberculosis, and could serve more generally as a model of the development of Th1-like responses in the human lung.

Adult↗
PubMed2003

Mitogen-activated protein kinases and retinal ischemia.

PURPOSE: Mitogen-activated protein kinases (MAPKs), consisting of three major enzymes-extracellular signal-regulated kinase (ERK), p38, and c-jun N-terminal kinase (JNK)-couple cell-surface receptors to critical regulatory targets and gene transcription. We hypothesized that MAPKs are differentially expressed and have distinct functions after retinal ischemia. METHODS: Rats were subjected to retinal ischemia by elevation of intraocular pressure. Changes in MAPK expression were examined by Western blot of whole retinal homogenates and by immunohistochemistry of retinal cryosections. Phosphorylated (activated) ERK, p38, and JNK proteins were localized by fluorescent double labeling. The functional significance of activated MAPKs was assessed using pharmacological antagonists. Specific MAPK blockade was documented by kinase assay and immunohistochemistry for phosphorylated target proteins. The outcome after ischemia was examined with electroretinography (ERG), by measuring retinal cell layer thickness in paraffin-embedded sections, and by TUNEL staining on retinal cryosections. Data were analyzed using ANOVA and post hoc t-test, with P < 0.05 considered significant. RESULTS: Expression of phosphorylated JNK and p38 increased significantly after ischemia and followed a specific time course, beginning at 1 hour, and persisting up to 1 week later. JNK and p38 were expressed in the nuclei of ganglion and amacrine cells, the outer plexiform layer, the nerve fiber layer, and the axonal terminals of bipolar cells. Phosphorylated ERK was expressed in Müller cells, peaking at 1 to 6 hours after ischemia. Blocking activation of p38 or ERK significantly improved recovery of the ERG b-wave after ischemia, dramatically decreased thinning of the inner nuclear layers, and decreased the percentage of TUNEL-positive cells. CONCLUSIONS: The MAPKs each demonstrate a specific cellular distribution after ischemia, and ERK and p38 are linked to apoptosis. Blockade of p38 or ERK provides significant protection from ischemic damage, suggesting a novel therapeutic role for MAPK inhibition in neuroprotection.

Animals↗
PubMed2003

Involvement of multiple transport systems in the disposition of an active metabolite of a prodrug-type new quinolone antibiotic, prulifloxacin.

Prulifloxacin is a prodrug-type new quinolone. The purpose of this study is to clarify the mechanism of biliary excretion and brain distribution of its active metabolite, UFX. UFX was efficiently excreted into the bile in rats, with its concentration in the bile being 30-60 times higher than that in plasma. The in vivo disposition study revealed that multidrug resistance-associated protein 2 (MRP2) was involved in the biliary excretion of glucuronide metabolite, but not of the unchanged UFX. A transport study using a P-glycoprotein (P-gp) overexpressing cell line, LLC-GA5-COL150, showed that UFX was a substrate of P-gp. Nevertheless, the biliary clearance (CLbile) of UFX in P-gp-gene-deficient mice was not different from that in the normal mice, although the concentration in the liver was slightly higher than that in the normal mice. These observations suggest that multiple transport systems are involved in the biliary excretion of UFX, with minor contribution of P-gp. The distribution of UFX in the rat brain was quite low, and its tissue to plasma concentration ratio (Kp) in the brain was much less than the unity and was increased by cyclosporin A. The Kp in the brain of mdr1a/1b(-/-) mice was higher than that in the normal mice, suggesting that efflux by P-gp played a major role in the limited brain distribution of UFX.

Journal Article↗
PubMed2003

Do antidotes for acute cyanide poisoning act on mercaptopyruvate sulfurtransferase to facilitate detoxification?

A well-known combined therapy for acute cyanide poisoning is intravenous administration of sodium nitrite, sodium thiosulfate and cobalt EDTA. Sodium nitrite oxidizes oxy-hemoglobin, resulting in methemoglobin, which has a high affinity for cyanide. Sodium thiosulfate is a substrate of thiosulfate: cyanide sulfurtransferase (rhodanese, EC.2.8.1.1), and facilitates catalytic metabolism of cyanide to less toxic thiocyanate. Cobalt EDTA combines with cyanide to reduce cyanide in the blood. Here, we focus on cytosolic and mitochondrial mercaptopyruvate sulfurtransferase (MST, EC. 2.8.1.2), which detoxifies cyanide more effectively than rhodanese, because rhodanese is localized only in mitochondria. Thiosulfate also serves as a substrate of MST and cyanide can be metabolized to thiocyanate. However, the K(m) value for thiosulfate is so large that it is not expected to contribute much to the detoxification of cyanide. On the other hand, nitrite and cobalt EDTA did not affect MST. Thus, combined therapy only slightly acts on MST to detoxify cyanide. Some investigators have attempted a new therapy in which mercaptopyruvate, a substrate of MST was administered intravenously, but this was not effective for detoxification due to the rapid decomposition of mercaptopyruvate in the blood. There are two possible strategies to facilitate MST activities: development of modified mercaptopyruvate with a longer half time and development of a chemical compound which indirectly increases transcription of MST via regulation of a DNA binding protein.

Acute Disease↗
PubMed2003

Morphological changes of cell proliferation and apoptosis in rat jejunal mucosa at different ages.

AIM: To study the changes of cell proliferation and apoptosis in rat jejunal epithelium at different ages. METHODS: Cell proliferation and apoptosis of the jejunal mucosal and glandulous epithelia from birth to postnatal 12(th) month were observed using immunocytochemistry (ICC), and TUNEL method. The height of villus, the thickness of muscle layer and the number of goblet cells in jejunal mucosal and glandulous epithelia were measured by BeiHang analytic software and analyzed by STAT. RESULTS: (1) Proliferating cell nuclear antigen (PCNA) positive cells of jejunal glandulous recess were found and increased in number from birth to the postnatal 3(rd) month. The number of PCNA positive cells peaked in the postnatal 3(rd) month, and decreased from then on. (2) The number of apoptotic cells also peaked in the postnatal 3(rd) month, showing a similar trend to that of the PCNA positive cells. (3) The height of jejunal villus increased after birth, peaked in the postnatal 3(rd) month and decreased from then on. The jejunal muscle layer became thicker in the postnatal 3(rd) week and the postnatal 12(th) month. The number of goblet cells of the jejunal mucosal and glandulous epithelia had a linear correlation with age. CONCLUSION: (1) PCNA positive cells are distributed in the jejunal glandulous recess. (2) Apoptotic cell number peaks in the postnatal 3(rd) month, indicating that cell proliferation and apoptosis are developed with the formation of digestive metabolism as rat grows to maturity. (3) The thickness of jejunal muscle layer increases to a maximum in the postnatal 3(rd) week, which may be related to the change in diet from milk to solid food. (4) The number of goblet cells increases rapidly in the postnatal 3(rd) week, probably due to ingestion of solid food.

Aging↗
PubMed2003

[Genetic polymorphism of six short tandem repeat loci in the Han population in Hebei province of China].

OBJECTIVE: This article reports a population genetic study on six short tandem repeat(STR) loci, D7S820, D19S253, D12S391, D5S818, D16S539 and D8S1179, in a sample of unrelated Chinese Han individuals(n=122-173) living in Hebei province. METHODS: DNA extraction from blood samples (200 in number) and multiplex amplification of the above six loci were carried out. Using denaturing polyacrylamide gel electrophoresis and silver stain, the authors investigated the distribution of allele frequencies of the six loci in Han population in Hebei province. RESULTS: The STR polymorphisms at all of the six loci were observed in Chinese Han population in Hebei province. The observed heterozygosities of D7S820, D19S253, D12S391, D5S818, D16S539 and D8S1179 were 0.828, 0.757, 0.769, 0.837, 0.785 and 0.852, respectively. The measured values of the power of discrimination (PD) were 0.914, 0.919, 0.940, 0.909, 0.917, 0.944; of the mean exclusion chance(MEC) 0.618, 0.740, 0.801, 0.557, 0.655, 0.696 and of the polymorphism information content (PIC) in Chinese 0.771, 0.760, 0.762, 0.708, 0.776 and 0.794, respectively. CONCLUSION: The genotype distributions of the six STR were in accordance with Hardy-Weinberg equilibrium. The numerical values of the PD and MEC are relatively high in Hebei province, and thus can be of significant application in population genetics and forensic medicine.

Asian People↗
PubMed2003

[Construction of recombinant pEGFP/hTRT plasmid].

OBJECTIVE: To construct a plasmid which has a reporter gene for exploring the role of human telomerase reverse transcriptase(hTRT) in in-vitro cell cultivation. METHODS: hTRT was cut by restricted enzyme from plasmid pGRN145 and inserted to plasmid pEGFP-C1 (enhanced green fluorescent protein). RESULTS: Restricted enzyme analysis and DNA sequencing showed that the sequence of the pEGFP -hTRT transgenic plasmid was correct. CONCLUSION: The recombinant vector pEGFP-hTRT has been successfully constructed, and it can be used as a transgenic plasmid in generating immortalized cell lines.

DNA-Binding Proteins↗
PubMed2003

[Biological characterization of immortalized porcine chondrocytes by introduction of telomerase].

The aim of this project was to acquire a clonal immortalized porcine chondrocyte cell line and to determine its biological characterization. Porcine auricle chondrocytes were infected with a retroviral vector pBABE-hTERT followed by selection with 2 micrograms/ml puromycin. RT-PCR and PCR-ELISA performed on separated colonies showed a cell line (TL1) with high and stable ectopic expression of hTERT. The growth curve, HE staining, flow cytometry, and tumorigenicity were analyzed to define the biological characterization of the immortalized chondrocytes. TL1 cells showed an increase in cellular viability and the reduction in apoptosis. But there was no malignant transformation and tumor development in nude mice. The changes of chondrocyte marker expression in this cell line revealed that it remained unstable phenotype. So high ectopic expression of hTERT is able to extend the life span of chondrocytes, but it unable to keep their differentiated phenotype during serial monolayer culture in vitro.

Aggrecans↗
PubMed2003

[Application of endolaser in vitrectomy for retinal vascular disease].

PURPOSE: To discuss the usage and effectiveness of endolaser in vitrectomy for retinal vascular disease. METHODS: Twenty-four cases (28 eyes) of vitrectomy for retinal vascular disease were treated with endolaser. The methods of endolaser: 21 eyes were treated with panretinal scatter therapy; 2 eyes with endolaser ring-intercepting around retinal and sealing retinal breaks; 5 eye with focal therapy. RESULTS: After follow-up for 1-24 months (mean 9 months), retinal hemorrhage recurred in 3 eyes; the other 25 eyes, retinas were totally reattached, retinal breaks were sealed, and vision had considerable recovery, no hemorrhage. The ratio of recovery is up to 89.2%. CONCLUSIONS: Endolaser is an important adjuvant in vitreous operation nowadays and an effective procedure in vitrectomy for the cases of retinal hemorrhage.

Adolescent↗
PubMed2003

[Cloning of human testicular carcinoma antigen MAGE-E1 gene and its expression in E.coli].

AIM: To clone and express the testicular carcinoma antigen MAGE-E1 gene in E.coli. METHODS: The cDNA encoding human MAGE-E1 gene was amplified by RT-PCR from human glioma cell line BT-325, then the MAGE-E1 gene was inserted into plasmid pGEM-T easy. After sequencing, the MAGE-E1 was cloned into the prokaryotic expression vector pGEX-4T-2 to construct the recombinant expression vector pGEX-4T-2-MAGE-E1 which was used to transform E.coli. RESULTS: The expressed product reached the highest level at 5 h after IPTG induction. SDS-PAGE and scanning analysis of gel density indicated that the expressed protein was about M(r) 41 000 and account for 35% of the total bacterial protein. CONCLUSION: The high efficient expression of the MAGE-E1 gene fragment lays the foundation for further preparing antibody against MAGE-E1 protein and the tumor vaccine for glioma immunotherapy.

Cloning, Molecular↗
PubMed2003

[Effects of Shenqi compound recipe on cell cycle and apoptosis of ascites inducible hepatocarcinoma cell line H22].

AIM: To observe the effects of Shenqi compound recipe (SQ) on cell cycle and apoptosis of hepatocarcinoma cell line H22 in-vitro and in-vivo. METHODS: BALB/c mice bearing tumors were perfused with SQ for 10 days running. And then cytotoxic activity of mouse NK cells and macrophages and variation of cell cycle of H22 cells were observed. Inhibition of H22 cell proliferation and induction of the their apoptosis by SQ were analyzed by flow cytometry. RESULTS: The tumor-suppre ssive rate of SQ was 65.68%. SQ could make H22 cells arrested at the S phase and induce their apoptosis. CONCLUSION: SQ has significant anti-tumor effect both in-vitro and in-vivo. Its mechanism may be related to blocking of cell cycle and inducing apoptosis of H22 cells.

Animals↗