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Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 145 records · Page 8Linked to original sources

Validation of the Oregon scientific BPW810 blood pressure monitor according to the European Society of Hypertension Protocol.

OBJECTIVE: To determine the accuracy of the BPW810 blood pressure monitor developed by IDT Technology Limited, according to the international protocol of the European Society of Hypertension. DESIGN: The international protocol is divided into two phases: the first phase is performed on 15 selected participants and, if the device passes this phase, 18 more participants are included making a total of 33 participants on whom the final validation is performed. METHOD: According to the European Society of Hypertension requirements, for each of the 33 participants, four blood pressure measurements were taken simultaneously by two trained observers, using mercury sphygmomanometers alternately with three measurements by the test device. The difference between the blood pressure value given by the device and mean of the two observers' readings was calculated for each measurement. The 99 differences were classified into zones (< or =5, < or =10, and < or =15 mmHg). The number of differences in each zone was compared with the number required by the international protocol. Furthermore, an individual analysis was then done to determine for each participant the number of comparisons < or =5 mmHg, which requires that at least 22 of the 33 participants should have two of three comparisons < or =5 mmHg. RESULTS: The BPW810 passed the first phase of the validation process for systolic and diastolic blood pressure. For the second phase, the difference between the device and mean of two observers was -2.2+/-4.8 mmHg for systolic blood pressure and -0.5+/-3.7 mmHg for diastolic blood pressure. In the last phase, 26 participants fell in the zone of two of the three comparisons lying within 5 mmHg and none of the participants fell in the zone of all three of the comparisons over 5 mmHg apart. CONCLUSION: The BPW810 passed all the phases of the international protocol for both systolic and diastolic blood pressure.

Adult↗

Characterization of an envelope protein (VP110) of White spot syndrome virus.

A protein of 110 kDa (termed VP110) from the envelope fraction of White spot syndrome virus (WSSV) was identified by SDS-PAGE and mass spectrometry. The resulting amino acid sequence matched an open reading frame (wsv035) containing an Arg-Gly-Asp (RGD) motif in the WSSV genome database. To validate the mass-spectrometry result, the C-terminal segment of the wsv035 open reading frame was expressed in Escherichia coli as a fusion protein, which was used to produce specific antibody. Analysis by Western blotting and immunoelectron microscopy demonstrated that VP110 was an envelope protein of WSSV. An interaction analysis was performed between VP110 and the host cells, using a fluorescence assay and a competitive-inhibition assay. The results showed that VP110 was capable of attaching to host cells and that adhesion could be inhibited by synthetic RGDT peptides, suggesting that the RGD motif in the VP110 sequence may play a role in WSSV infection.

Amino Acid Motifs↗

Using transthoracic two-dimensional echocardiography to guide the placement of coronary sinus catheters: a randomized study.

OBJECTIVE: To assess the value of transthoracic echocardiography (TTE) as an image guide in placing a coronary sinus catheter into the coronary sinus. METHODS: Sixty consecutive patients undergoing electrophysiologic study were randomized to TTE (30 patients, "TTE group") or x-ray fluoroscopy (30 patients, "x-ray group") as an image guide to assist in the placement of a coronary sinus catheter. RESULTS: The success rate of placing the coronary sinus catheter was 96.7% in TTE group and 100% in x-ray group (P > 0.05). The procedure duration was 5.8 +/- 5.7 minutes in TTE group and 5.9 +/- 3.3 minutes in x-ray group (P > 0.05), The x-ray exposure time was 0.15 +/- 0 minute in TTE group and 4.2 +/- 2.8 minutes in x-ray group (P < 0.0001). CONCLUSION: Using TTE as an image guide, coronary sinus cannulation is feasible and as rapid as standard x-ray fluoroscopy, without the radiation risk.

Adult↗

Selective biodegradation of S and N heterocycles by a recombinant Rhodococcus erythropolis strain containing carbazole dioxygenase.

The carbazole dioxygenase genes were introduced into a dibenzothiophene degrader. The recombinant Rhodococcus erythropolis SN8 was capable of efficiently degrading dibenzothiophene and carbazole simultaneously. SN8 could also degrade various alkylated derivatives of carbazole and dibenzothiophene in FS4800 crude oil by just a one-step bioprocess.

Biodegradation, Environmental↗

Phenotypic switching in a Cryptococcus neoformans variety gattii strain is associated with changes in virulence and promotes dissemination to the central nervous system.

This is the first report of a Cryptococcus neoformans var. gattii strain (serotype B) that switches reversibly between its parent mucoid (NP1-MC) colony morphology and a smooth (NP1-SM) colony morphology. Similar to C. neoformans var. grubii and C. neoformans var. neoformans strains, the switch is associated with changes in the polysaccharide capsule and virulence in animal models. In murine infection models, NP1-MC is significantly more virulent than NP1-SM (P < 0.021). In contrast to the serotype A and D strains, the serotype B strain switches in vivo reversibly between both colony morphologies. The polysaccharide of NP1-MC exhibits a thicker capsule, and thus NP1-MC exhibits enhanced intracellular survival in macrophages. Consistent with this finding, switching to the mucoid variant is observed in pulmonary infection with NP1-SM. In contrast, the thin polysaccharide capsule of NP1-SM permits better crossing of the blood-brain barrier. In this regard, only smooth colonies were grown from brain homogenates of NP1-MC-infected mice. Our findings have important implications for the pathogenesis of cryptococcosis and suggest that phenotypic switching affects host-pathogen interactions in the local microenvironment. This altered interaction then selects for specific colony variants to arise in a pathogen population.

Animals↗

Polymorphisms in polycyclic aromatic hydrocarbon metabolism and conjugation genes, interactions with smoking and prostate cancer risk.

The relationship between cigarette smoking and prostate cancer remains unclear. Any potential association may depend on the individuals' ability to metabolize and detoxify cigarette carcinogens--such as polycyclic aromatic hydrocarbons. To investigate this, we studied the association between prostate cancer and smoking, as well as the main and modifying effects of functional polymorphisms in genes that metabolize polycyclic aromatic hydrocarbons (CYP1A1 Ile(462)Val, microsomal epoxide hydrolase His(139)Arg) and detoxify reactive derivatives (GSTM1 null deletion, GSTT1 null deletion, GSTP1 Ile(105)Val and Ala(114)Val) using a family-based case-control design (439 prostate cancer cases and 479 brother controls). Within the entire study population, there were no main effects for smoking or any of the polymorphisms. However, the nondeleted GSTM1 allele was inversely associated with prostate cancer [odds ratio (OR), 0.50; 95% confidence interval (95% CI), 0.26-0.94] among men with less aggressive disease (Gleason score < 7 and clinical tumor stage < T2c) and positively associated (OR, 1.68; 95% CI, 1.01-2.79) with prostate cancer in men with more aggressive disease (Gleason score > or = 7 or clinical tumor stage > or = T2c). We also found a statistically significant negative multiplicative interaction between the GSTM1 nondeleted allele and heavy smoking (> 20 pack-years) in the total study population (P = 0.01) and in Caucasians (P = 0.01). Among Caucasians, heavy smoking increased prostate cancer risk nearly 2-fold in those with the GSTM1 null genotype (OR, 1.73; 95% CI, 0.99-3.05) but this increased risk was not observed in heavy smokers who carried the GSTM1 nondeleted allele (OR, 0.95; 95% CI, 0.53-1.71). Our results highlight the importance of considering genetic modifiers of carcinogens when evaluating smoking in prostate cancer.

Case-Control Studies↗

Age-related changes of the cutaneous microcirculation in vivo.

BACKGROUND: The architectural frameworks of the skin microcirculation are rather complex and change continuously with aging. But these changes are yet poorly documented in vivo. OBJECTIVES: Using non-invasive methods belonging to the field of biometrology, the study aimed to investigate quantitatively the changes of the cutaneous microvasculature in different anatomic sites with age. METHODS: Measurements were performed on crow's feet, forehead, volar forearm and dorsum of hand in 50 women (aged 20-74 years who consisted of 10 probands in each live decades). The superficial vascular plexus was scanned by videocapillaroscopy and assessed with the software Capilab Toolbox. The subpapillary vascular plexus was explored with laser Doppler flowmetry. The skin color a* was analyzed by chromametry. RESULTS: A marked site and age effect on the skin microcirculation has been demonstrated. The density of capillary loops in the eldest group decreased by about 40-70% compared with the youngest group whereas the vascular length increased by 35-156%. The capillary density in the back of the hand was 4 times higher than in the crow's feet. The vascular length in the crow's feet was 3 times longer than in the back of the hand. Both blood flow and skin redness (a*) increased also with age. CONCLUSION: Both morphology and quantification of the cutaneous microvasculature showed changes with site and age. Videocapillaroscopy associated to an image processing and laser Doppler flowmetry revealed different vascular layers. So the combination of both instruments offers an easy way to observe the architectural frameworks in vivo.

Adult↗

Formation of uniform single-crystalline bismuth sulfide nanowires under mixed-solvent condition.

Uniform single-crystalline bismuth sulfide nanowires were prepared via a convenient solvothermal route under mixed-solvent condition. The nanowires were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray (EDX) spectrometry and UV-vis spectrophotometer. The growth mechanism of the one-dimensional nanostructures was discussed. The optical absorption band gap of the nanowires is about 1.7 eV, and the blue-shift phenomenon can be observed with respect of that of the bulk Bi2S3, which might bring in new types of applications.

Bismuth↗

Uveal melanocytes do not respond to or express receptors for alpha-melanocyte-stimulating hormone.

PURPOSE: Whereas cutaneous pigmentation increases after exposure to ultraviolet (UV) irradiation, ocular pigmentation does not. This study was designed to examine the evidence that alpha-melanocyte-stimulating hormone (alpha-MSH), which is thought to be the mediator of UV response in the skin, has any role to play in uveal melanocytes. METHODS: Human uveal melanocytes derived from the choroid and the iris were cultivated by using eyes harvested from adult cadaveric donors and were assessed by Northern blot analysis for growth and melanogenic response to alpha-MSH and expression of the receptor for alpha-MSH (MC1-R). In addition, expression of alpha-MSH was evaluated in ocular tissue by immunocytochemistry. RESULTS: Uveal melanocytes, unlike cutaneous melanocytes in vitro, exhibited no stimulation of proliferation in response to alpha-MSH at dosages ranging from 0.1 to 100 muM. In addition, tyrosine hydroxylase, DOPA oxidase, and protein levels for tyrosinase, TRP-1, and TRP-2 were not influenced by alpha-MSH. Associated with the lack of alpha-MSH response in cultured uveal melanocytes was the absence of expression of the receptor for alpha-MSH (MC1-R), as assessed by Northern blot analysis. Also in contrast to the skin, pigmented ocular tissue lacked expression of the alpha-MSH ligand, as assessed by immunocytochemistry. CONCLUSIONS: In conclusion, ocular pigmentation does not appear to be regulated by melanocyte stimulating hormone.

Blotting, Northern↗

Optimization and physicochemical characterization of thermosensitive poloxamer gel containing puerarin for ophthalmic use.

The purpose of this study was to systematically optimize an ophthalmic thermosensitive poloxamer analogs gel containing puerarin that was a free flowing liquid below the room temperature and could shift to a gel with an eligible gel strength and bioadhesive force in physiological condition (dilution by the simulated tear fluid and at 35.0 degrees C). A two-factor, five-level central composite design (CCD) was employed to the optimization procedure. The effect of formulation variables (the w/v concentration of poloxamer 407 (X1) and poloxamer 188 (X2)) on a number of response variables (the gelation temperature before (Y1) and after (Y2) the simulated tear fluid diluted, the difference between them (Y3)) was systemically investigated. A second order polynomial equation was fitted to the data. The resulting equation and response surface plots were used to predict the responses in the optimal region. Finally, 21.0% (w/v) poloxamer 407 and 5.0% (w/v) poloxamer188 were chosen as the optimal poloxamer gel matrix. The influence of the other ingredients on the physicochemical properties of the formulation was also investigated. Hydroxypropyl-beta-cyclodextrin (HPCD) enhanced the gelation temperature and reduced the gel strength and the bioadhesive force, while puerarin and benzalkonium chloride (BC) had a comparatively smaller influence. All the isotonicity agents studied had the gelation temperatures lowered, and the gel strengths and the bioadhesive forces enhanced. But only sodium chloride appears to be a promising isotonicity agent for the poloxamer gel containing puerarin, HPCD and BC.

2-Hydroxypropyl-beta-cyclodextrin↗

Increased migration of vascular adventitial fibroblasts from spontaneously hypertensive rats.

Experimental evidence has suggested that vascular adventitial fibroblasts (AFs) may migrate into the neointima of arteries after balloon injury in various animal models. However, the research on migration of AFs has been limited to the effects of acute vascular injury. The role of AFs in chronic vascular injury and hypertension is not yet known. In this study, the migration of spontaneously hypertensive rat (SHR)-AFs and Wistar-Kyoto rat (WKY)-AFs from the thoracic aorta was determined by a transwell technique. Our results showed that fetal calf serum, angiotensin II (Ang II), phorbol ester, basic fibroblast growth factor and platelet-derived growth factor-BB induced migration in a dose-dependent manner, and the migration of SHR-AFs was always greater than that of WKY-AFs. Ang II-induced migration of AFs was considered to have been mediated by Ang II type 1 receptor (AT1-R), because the AT1-R antagonist losartan (10(-7)-10(-5) mol/l) suppressed Ang II-induced migration. Ang II-induced migration was also blocked by the extracellular-regulated protein kinase 1/2 (ERK1/2) inhibitor PD98059 (10(-5) mol/l) and p38 kinase inhibitor SB202190 (10(-5) mol/l), indicating that ERK1/2 and p38 kinase were involved in Ang II-induced migration. Ang II (10(-7) mol/l)-induced ERK1/2 and p38 kinase phosphorylation, both of which peaked after 5 min, were suppressed by PD98059 and SB202190, respectively. The Ang-II induced phosphorylation of both proteins was suppressed by losartan, whereas no effect was observed with PD123319, a specific inhibitor of Ang II type 2 receptor (AT2-R). Thus, in the present study, various factors stimulated the migration of SHR-AFs and, to a leber extent, WKY-AFs from the thoracic aorta, and the ERK1/2 and p38 kinase pathways are involved in Ang II-stimulated migration of fibroblasts.

Angiotensin II↗

[Analysis of diffuse large B-cell lymphoma heterogeneity based on coupled two-way clustering].

Microarray technology has proposed a powerful tool in dealing with the heterogeneity of disease. Currently, many methods in the field are based on traditional hierarchical clustering to discover subtypes of disease using a large number of genes on microarray.However, they did not considered that large unrelated noise (genes)may mask significant partitions and correlations of disease samples. To avoid the shortcoming, this paper presented a heterogeneous analysis based on coupled two-way clustering (HCTWC) to search interesting gene signature and find the natural partitions of disease samples. The method was applied to diffuse large B-cell lymphoma (DLBCL) microarray dataset. By identifying significant gene signature, we were able to discover the two new subtypes of DLBCL with survival rate 55% and 25% respectively. The results showed that HCTWC had the potential to be a powerful tool for solving the heterogeneity of disease on gene expression profile.

Cluster Analysis↗

[Analysis of genetic variation of abalone (Haliotis discus hannai) populations with microsatellite markers].

Microsatellite markers were used to access the genetic variation in three populations of abalone Haliotis discus hannai. Two wild populations were collected from the sea areas in Changdao, Shandong and Dalian, Liaoning respectively. A cultivated population originated from the sea area in Kongdongdao, Shangdong. Six microsatellite loci were screened for genetic polymorphism. Polymorphic information content (PIC) value per loci was greater than 0.5 and can be used to analysis of genetic structure of the three abalone populations. Fifty-seven alleles were amplified from the three populations in six microsatellite loci. The average number of alleles (A) was 9.50 and the effective number of alleles (Ne) was 5.8572. The mean observed heterozygosity (Ho) and the mean expected heterozygosity (He) were 0.6925 and 0.7966, respectively. The Ho and He of two wild abalone populations were higher than that of cultured population. All these results provide a basis for conservation and utilization of genetic diversity of Haliotis discus hannai.

Animals↗

Overexpression of MDR1 using a retroviral vector differentially regulates genes involved in detoxification and apoptosis and confers radioprotection.

Overexpression of P-glycoprotein (P-gp), the product of the MDR1 (multidrug resistance 1) gene, might complement chemotherapy and radiotherapy in the treatment of tumors. However, for safety and mechanistic reasons, it is important to know whether MDR1 overexpression influences the expression of other genes. Therefore, we analyzed differential gene expression in cells of the human lymphoblast cell line TK6 retrovirally transduced with MDR1 using the GeneChip Human Genome U133 Plus2.0 (Affymetrix). Sixty-one annotated genes showed a significant change in expression (P < 10(-4)) in MDR1-overexpressing cells compared to untransduced cells and cells transduced with a control virus expressing the neomycin phosphotransferase gene. Several genes coding for proteins involved in detoxification and exocytosis showed approximately 1.4- 4-fold increases in transcript levels (e.g. ALDH1A, UNC13). Additionally, pro-apoptosis genes were down-regulated (e.g. twofold for CASP1, 2.5-fold for NALP7) with concomitant increased expression of the potential anti-apoptosis gene AKT3. In functional assays the influence of MDR1 overexpression on apoptosis signaling was further corroborated by showing reduced rates of apoptosis in response to irradiation in TK6 cells transduced with MDR1. In conclusion, the resistant phenotype of MDR1-mediated P-gp-overexpressing cells is associated with differential expression of genes coding for metabolic and apoptosis-related proteins. These results have important implications for understanding the mechanisms by which MDR1 gene therapy can protect normal tissues from radiation- or chemotherapy-induced damage during tumor treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Genetic diversity of nine populations of the black goat (Capra hircus) in Sichuan, PR China.

Sixteen polymorphic primers screened from 100 random primers were selected to analyze the randomly amplified polymorphic DNA (RAPD) of 540 domesticated black goats (Capra hircas) from 9 different geographical populations in Sichuan Province of China. After the test, 170 entirely repeatable RAPD markers representing goat polymorphisms were obtained from the 16 polymorphic primers, the lengths of the markers ranging from 0.1 to 2.5 kb. The genetic distance among the black goat populations ranges from 0.1051 to 0.2978. The similarity coefficient (0.9002) between Jintang and Lezhi black goats was the highest in the 9 populations, followed by the coefficient (0.8953) between Jialing and Yinshan goats, while that between Jiangan and Huili goats was found to be the lowest (0.7424). The coefficient of differentiation among population genes (Gst) was 0.2766, indicating a comparatively low degree of differentiation among the black goat populations. A UPGMA dendrogram constructed from similarity coefficients showed that the two populations from Huili and Baiyu, which are found mostly on the Western Sichuan plateau and in mountainous areas, clustered together, and the other seven populations formed another group. It can also be clearly seen that the Huili and Baiyu populations are very special, and must have been closely related in the past, even though their link with the other populations is quite weak as a result of genetic communication. The results of the experiment offer some crucial scientific data useful for the breeding of black goats.

Animals↗

Determination of ceftriaxone sodium in pharmaceutical formulations by flow injection analysis with acid potassium permanganate chemiluminescence detection.

Based on the chemiluminescence (CL) emission generated from the oxidation of ceftriaxone sodium alkali hydrolysate by potassium permanganate in polyphosphoric acid (PPA), a novel determination method for ceftriaxone sodium was developed by using a flow-injection technique. The calibration curve appears to be linear in the range between 0.05 and 100 microg mL(-1) with a detection limit (3sigma) of 25 ng mL(-1), and a relative standard deviation (RSD) of 0.6% for eleven replicate determinations of 5.0 microg mL(-1) ceftriaxone sodium. The proposed method has been successfully utilized for the determination of ceftriaxone sodium in pharmaceutical formulations, while the chemiluminescence reaction mechanisms were investigated.

Calibration↗