Biomedical subjects

W Cai

Publications and source records attributed to W Cai.

At least 19 recordsLinked to original sources

PubMed2006

Fascin is a potential biomarker for early-stage oesophageal squamous cell carcinoma.

BACKGROUND: Fascin, an actin-binding protein, is usually expressed at a low level in normal epithelium, but is markedly up regulated in several types of carcinomas. Reports on fascin expression in oesophageal squamous cell carcinoma (ESCC) and precancerous lesions remain rare. AIM: To show the roles of fascin in the progression from normal epithelium to invasive ESCC. METHODS: Fascin expression in 102 sections embedded in paraffin wax, including samples of normal mucosa (n = 20), dysplasia (n = 10), ESCC (n = 62) and special sections (n = 10) of a full-length mucosa layer from the distant margin to the cancer focus of the excised oesophagus, and 49 fresh specimens of ESCC was analysed by immunohistochemistry, western blot and real-time reverse transcription-polymerase chain reaction. Fascin expression in ESCC cell lines was also investigated. RESULTS: In the immunohistochemical study, the positive rate of fascin was significantly higher in the tumour tissue than in the normal epithelium (p = 0.020), but no significant difference was shown between ESCC and dysplasia (p = 1.000). Immunostaining for fascin was only apparent in the basal layer of the normal epithelium. However, in the dysplasia, positive staining was observed in most of the heterogeneous cells from the basal layer to the granular layer of the epithelium. Fascin expression was seen to increase progressively from the normal epithelium to invasive ESCC. Up regulation of fascin was observed in 87.76% (43/49) and 77.55% (38/49) of the specimens, respectively, using western blot and real-time reverse transcription-polymerase chain reaction assays; 80% (4/5) of ESCC cell lines also expressed fascin at a high level. Furthermore, overexpression of fascin was markedly correlated with cell proliferation and lymph node metastasis. CONCLUSIONS: These findings suggested that fascin was associated with the transformation and development of ESCC and implicated the potential of fascin as a novel biomarker that would allow the tumour to be identified at an early stage in high-risk individuals.

Adult↗

PubMed2006

Study on energy metabolism in perioperative infants.

OBJECTIVES: To evaluate resting energy expenditure (REE) in surgical infants and define the effects of the degree of stress on its level. SUBJECTS AND METHODS: Between June 1999 and June 2003 forty-five infants awaiting surgery (boys/girls: 32/13) from the Department of Pediatric Surgery were entered in the study. Indirect calorimetry was used to measure the REE of all the patients before operation and 1 - 7 days after operation. Clinical data were collected, including age, weight, height, diagnosis, operative method, site and duration, and first day postoperative C-reactive protein (CRP) levels. RESULTS: The REE before operation did not differ significantly from the postoperative values (paired t-test, p > 0.05). The predicted REE was significantly higher than the measured REE even before and after the operation (p < 0.01). REE values in the first three postoperative days were lower in the mild stress group than in the severe surgical stress group. CONCLUSIONS: REE variation among the patients is relatively large. Changes in REE may be related to the degree of stress. Predicted REE values may be not a good reflection of measured REE.

Calorimetry↗

PubMed2006

Multicenter comparison of nucleic acid extraction methods for detection of severe acute respiratory syndrome coronavirus RNA in stool specimens.

The emergence of a novel coronavirus (CoV) as the cause of severe acute respiratory syndrome (SARS) catalyzed the development of rapid diagnostic tests. Stool samples have been shown to be appropriate for diagnostic testing for SARS CoV, although it has been recognized to be a heterogeneous and difficult sample that contains amplification inhibitors. Limited information on the efficiency of extraction methods for the purification and concentration of SARS CoV RNA from stool samples is available. Our study objectives were to determine the optimal extraction method for SARS CoV RNA detection and to examine the effect of increased specimen volume for the detection of SARS CoV RNA in stool specimens. We conducted a multicenter evaluation of four automated and four manual extraction methods using dilutions of viral lysate in replicate mock stool samples, followed by quantitation of SARS CoV RNA using real-time reverse transcriptase PCR. The sensitivities of the manual methods ranged from 50% to 100%, with the Cortex Biochem Magazorb method, a magnetic bead isolation method, allowing detection of all 12 positive samples. The sensitivities of the automated methods ranged from 75% to 100%. The bioMérieux NucliSens automated extractor and miniMag extraction methods each had a sensitivity of 100%. Examination of the copy numbers detected and the generation of 10-fold dilutions of the extracted material indicated that a number of extraction methods retained inhibitory substances that prevented optimal amplification. Increasing the volume of sample input did improve detection. This information could be useful for the extraction of other RNA viruses from stool samples and demonstrates the need to evaluate extraction methods for different specimen types.

Feces↗

PubMed2005

Analytical form of the particle distribution based on the cumulant solution of the elastic Boltzmann transport equation.

An analytical expression of the particle distribution based on an analytical cumulant solution of the time-dependent elastic Boltzmann transport equation (BTE) is presented. This expression improves upon the previous second order cumulant solution of the BTE described by a Gaussian distribution in two aspects: (1) separating the ballistic component from the scattered component to ensure that the summation in expressions is convergent; and (2) enforcing the causality condition to ensure that no particle travels faster than the free speed of the particles. Time-resolved profiles obtained using the analytical form are compared with those obtained by the Monte Carlo simulation, for both transmission and backscattering. The calculating time using our analytical form is much faster than that using the Monte Carlo approach.

Journal Article↗

PubMed2005

The formation, role and removal of NO3-N during corona discharge in air for phenol removal.

Pulsed corona discharge carried out in the gas phase has been shown to be a low cost solution for wastewater treatment. In this study, the results show that the nitrogen dissociated during corona discharge in the gas phase formed nitric acid in solution, which resulted in a drop in solution pH. The phenol removal could be described in accordance with a first-order reaction in a basic buffer solution, but not in initial neutral and basic non-buffered solutions. This indicates that basic conditions facilitate phenol removal, whilst the formation of nitric acid in solution resulted in decrease in the phenol removal rate. This study also shows that most of the oxidants used for phenol removal came mainly from the dissociation of water molecules at the surface of the liquid phase and/or the gas phase very close to the liquid surface in discharging conditions, not from the gas dissociation in the bulk gas phase, and therefore, it is more effective to keep the solution basic than to change the component of gas in the reactor when removing phenol from water using corona discharge.

Cost Control↗

PubMed2004

Multiple passages of light through an absorption inhomogeneity in optical imaging of turbid media.

Multiple passages of light through an absorption inhomogeneity of finite size deep within a turbid medium are analyzed for optical imaging by use of the self-energy diagram. The nonlinear correction becomes more important for an inhomogeneity of a larger size and with greater contrast in absorption with respect to the host background. The nonlinear correction factor agrees well with that from Monte Carlo simulations for cw light. The correction is approximately 50%-75% in the near infrared for an absorption inhomogeneity with the typical optical properties found in tissues and five times the size of the transport mean free path.

Light↗

PubMed2004

Cultivation of aerobic granules in a sequential batch shaking reactor.

Aerobic granular sludge is a promising biotechnology for wastewater treatment system. In this report, aerobic granular sludge was successfully cultivated in a sequential batch shaking reactor in which horizontal circular flow could be formed by shaking. In this way, granulation and aeration could be simultaneously achieved. In comparison with sequential batch airlift reactor, more homogeneous circular flow was formed in the sequential batch shaking reactor. The aerobic granules obtained in the reactor were smooth, 1.2 mm in average diameter, and had a settling velocity of 50-52 m h(-1). In addition, an increase in the hydrophobicity of the cell surface of granules indicated that granulation could be related to the change in cell hydrophobicity. Finally, microbial observation showed that rod-shape and coccoid bacteria were the dominant species in mature granules. Results of this study have important implications on the mechanism of the granulation process and further practical application.

Bacteria, Aerobic↗

PubMed2003

Description and clinical treatment of an early outbreak of severe acute respiratory syndrome (SARS) in Guangzhou, PR China.

Severe acute respiratory syndrome (SARS), now known to be caused by a coronavirus, probably originated in Guangdong province in southern China in late 2002. The first major outbreak occurred in Guangzhou, the capital of Guangdong, between January and March 2003. This study reviews the clinical presentation, laboratory findings and response to four different treatment protocols. Case notes and laboratory findings were analysed and outcome measures were collected prospectively. The SARS outbreak in Guangdong province and the outbreak in Guangzhou associated with hospitals in the city are described, documenting clinical and laboratory features in a cohort of 190 patients randomly allocated to four treatment regimens. Patients were infected by close contact in either family or health-care settings, particularly following procedures likely to generate aerosols of respiratory secretions (e.g. administration of nebulized drugs and bronchoscopy). The earliest symptom was a high fever followed, in most patients, by dyspnoea, cough and myalgia, with 24 % of patients complaining of diarrhoea. The most frequent chest X-ray changes were patchy consolidation with progression to bilateral bronchopneumonia over 5-10 days. Thirty-six cases developed adult respiratory distress syndrome (ARDS), of whom 11 died. There was no response to antibiotics. The best response (no deaths) was seen in the group of 60 patients receiving early high-dose steroids and nasal CPAP (continuous airway positive pressure) ventilation; the other three treatment groups had significant mortality. Cross-infection to medical and nursing staff was completely prevented in one hospital by rigid adherence to barrier precautions during contact with infected patients. The use of rapid case identification and quarantine has controlled the outbreak in Guangzhou, in which more than 350 patients have been infected. Early administration of high-dose steroids and CPAP ventilation appears to offer the best supportive treatment with a reduced mortality compared with other treatment regimens.

Adult↗

PubMed2002

Photon migration in turbid media using a cumulant approximation to radiative transfer.

A photon transport model for light migration in turbid media based on a cumulant approximation to radiative transfer is presented for image reconstruction inside an infinite medium or a bounded medium with a planar geometry. This model treats weak inhomogeneities through a Born approximation of the Boltzmann radiative transfer equation and uses the second-order cumulant solution of photon density to the Boltzmann equation as the Green's function for the uniform background. It provides the correct behavior of photon migration at early times and reduces at long times to the center-moved diffusion approximation. At early times, it agrees much better with the result from the Monte Carlo simulation than the diffusion approximation. Both approximations agree well with the Monte Carlo simulation at later times. The weight function for image reconstruction under this proposed model is shown to have a strong dependence at both early and later times on absorption and/or scattering inhomogeneities located in the propagation direction of and close to the source, or in the field of view of and close to the detector. This effect originates from the initial ballistic motion of incident photons, which is substantially underestimated by the diffusion approximation.

Journal Article↗

PubMed2001

Identification of dopamine responsive mRNAs in glial cells by suppression subtractive hybridization.

Recent studies have established that glial cells are important targets of the neurotransmitter dopamine (DA), but the regulatory effects of DA on glial cells have not been extensively studied. In the present study, we have investigated the influence of DA on gene transcription in glial cells. Two-directional (forward and backward) suppression subtraction hybridization (SSH) was performed on astrocytes cultured from rat cerebral tissues in standard media or in culture media treated with DA. PCR-select differential screening was used to further verify the differentially expressed cDNA clones, positive clones were sequenced, and the mRNAs were re-examined on Northern blots. Fourteen sequences were identified of which eleven are homologous to known genes, three are homologous to expressed sequence tags (ESTs). Three novel full-length cDNAs were isolated using the EST fragments as probes to screen a cDNA library constructed from human brain. Analysis of these sequences suggested that complex intracellular signaling pathways, involving crosstalk with growth factor pathways, steroid hormone pathways, and an interferon-regulated 2-5 A pathway, are responsive to DA in astrocytes. The responsive proteins downstream from the signaling pathways were found to fall into at least three groups, including a series of metabolic enzymes, stress proteins, transfer proteins, etc. In addition, several of them have established their relationships with specific neurodegenerative diseases, showing that there is overlap in the pathogenic mechanisms of different diseases. Our results have provided a foundation for better understanding of the molecular basis of glial cell functions in dopaminergic transmission and an approach to find possible medication for the related disorders.

Animals↗

PubMed2001

Anisotropic elastic interactions of a periodic dislocation array.

A method for calculating the anisotropic elastic energy of a dislocation dipole in a periodic cell is derived in which the infinite image summation is absolutely convergent. The core energy of a screw dislocation in Si, extracted from atomistic simulation, is shown to be manifestly system size invariant. Existence of special cell geometry where complete cancellation of elastic interactions occurs is demonstrated.

Journal Article↗

PubMed2001

A two-dimensional immune algorithm for resolution of overlapping two-way chromatograms.

A two-dimensional immune algorithm is proposed for resolving the multicomponent overlapping two-way data matrices. The method is a development of the one-dimensional immune algorithm proposed elsewhere. When the inner product of vectors is expanded to the similar operation on matrices, the 1D immune algorithm can be expanded to the 2D algorithm which is suitable for the analysis of two-way data matrices. Both simulated and experimental two-way data sets were investigated by the method, and the results prove that the 2D immune algorithm is an effective tool for resolving the overlapping two-way signals. The effect of noise on the recoveries is also discussed.

Algorithms↗

PubMed2001

[Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in the Han and Li nationalities in Hainan, China and identification of a new mutation in human G6PD gene].

OBJECTIVE: To elucidate the molecular basis of G6PD deficiency in the Han and Li nationalities in Hainan, China. METHODS: Polymerase chain reaction and restriction enzyme digestion were used to screen the mutations 1388G-->A, 1360C-->T, 1024C-->T, 592C-->T, 517T-->C, 493A-->G, 487G-->A, 392G-->T and 95A-->G. Single strand conformation polymorphism analysis was used to screen the other mutations followed by DNA sequencing to characterize the mutations of the samples with abnormal SSCP bands. RESULTS: Of the fifty-nine Han cases with G6PD deficiency, fourteen with 1388G-->A (23.7%), three with 871G-->A(5.1%), one with 835A-->T(1.7%), one with 517T-->C (1.7%), three with 392G-->T(5.1%), and four with 95A-->G(6.8%) were found. Of the thirty-two Li cases with G6PD deficiency, six with 1388G-->A(18.8%), three with 871G-->A(9.4%), and two with 95A-->G(6.3%) were found. A new mutation 835A-->G which causes the substitution of Ala for Thr at 279 in a Han case was identified and named as G6PD Haikou. The enzyme activity of the variant is about 10% of the normal and lower than the activity of the variant 835A-->T with about 40% of the normal. Analysis of the 3D model of human G6PD has revealed that the hydroxyl group of Thr at 279 is a group in maintaining the interaction of the G6PD subunits. CONCLUSION: The most common mutations of G6PD deficiency in Han and Li nationalities in Hainan are similar. Compared with the mutation spectrum of G6PD gene in the populations in other regions of China, the results indicate that some G6PD gene mutations are widespread in the populations of different regions in the southern part of China. The hydroxyl group of the Thr at 279 of human G6PD may be a necessary group for maintaining the interaction of the G6PD subunits and the enzyme activity.

Child↗

PubMed2001

[Histological changes in 20 hepatic fibrosis patients with chronic hepatitis B after recombinant human interferon-gamma treatment].

OBJECTIVE: To observe histological changes of hepatic fibrosis patients with chronic hepatitis B after recombinant human interferon-gamma treatment. METHODS: Twenty hepatic fibrosis patients with chronic hepatitis B received rhIFN-gamma treatment at the dose of 1 MU intramuscularly daily for the first three months and every other day for the next six months. Liver biopsy was performed at the start of the therapy and the end of 9-month follow-up period respectively in all patients. All liver biopsy specimens were stained with hematoxylin-eosin and picro-sirius red. Modified Scheuer and Chevallier semi-quantitative scoring system was used to assess the results. In the meantime, serum hepatic fibrosis indices and serum biochemical examination were detected. RESULTS: After 9 moths of treatment, the mean fibrosis score decreased from 11.24 +/- 5.34 to 8.67 +/- 4.16 (P<0.01), whereas the mean inflammation score decreased from 12.78 +/- 5.19 to 6.57 +/- 2.95 (P<0.01). CONCLUSIONS: rhIFN-gamma showes a beneficial effect on hepatic fibrosis patients with chronic hepatitis B.

Adolescent↗

PubMed2001

Placental leptin correlates with intrauterine fetal growth and development.

OBJECTIVE: To study the role of placental leptin in intrauterine cord leptin production and its relationship with neonatal anthropometry. METHODS: Forty women and their babies (40) were enrolled in this study. Placental tissues were assayed for leptin mRNA by reverse transcription/polymerase chain reaction (RT/PCR), and assayed for the obese gene protein leptin by Western-blot and immunohistochemistry. Blood was taken from the umbilical cord of the babies at delivery. Serum leptin was measured by radio-immunoassay. Neonatal anthropometric measurements were recorded within 48 hours after delivery. Linear regression analysis was used to explore the relationship between placental leptin, cord leptin and neonatal anthropometric measures. RESULTS: The obese gene was expressed in placental tissue at comparable or greater levels than that in adipose tissue. The placentas of the small for gestational age (SGA) neonates expressed leptin mRNA and protein at significantly lower levels than those of the appropriate for gestational age (AGA) neonates (P = 0.0034 and 0.0076), while the placentas of the large for gestational age (LGA) neonates expressed leptin mRNA and protein at significantly higher levels than those of the AGA neonates (P = 0.043 and 0.021). Linear regression analysis showed placental ob gene transcription and leptin translation correlated significantly with cord leptin (r = 0.39 and 0.43), and neonatal Ponderal Index (r = 0.66 and 0.69). CONCLUSION: The placenta provides a source of leptin for the growing fetus, and this placental leptin might be a growth factor in intrauterine fetal development.

Blotting, Western↗

PubMed2001

Lysozyme enhances renal excretion of advanced glycation endproducts in vivo and suppresses adverse age-mediated cellular effects in vitro: a potential AGE sequestration therapy for diabetic nephropathy?

BACKGROUND: Lysozyme (LZ), a host-defense protein, contains an 18 amino-acid domain with high affinity binding for sugar-derived proteins or lipids, called advanced glycation endproducts (AGE), that are implicated in diabetes- and age-dependent complications (DC). MATERIALS AND METHODS: A) The effects of LZ on AGE- removal were tested in vivo. LZ was injected (200 ug/day, i.p., X2 weeks) in non-obese diabetic (NOD), db/db (+/+) mice, and non-diabetic, AGE-infused Sprague-Dawley rats. B) LZ: AGE interactions with macrophage-like T1B-183 cells (Mf) and mesangial cells (MC) were tested in vitro. RESULTS: A) In NOD mice, LZ reduced the elevated basal serum AGE (sAGE) (p < 0.05), enhanced urinary AGE (uAGE) excretion by approximately 2-fold (p < 0.01), while it reduced albuminuria (UA), p < 0.005. In db/db mice, LZ infusion also reduced the elevated sAGE (p < 0.05), doubled uAGE excretion (p < 0.05), and decreased UA (p < 0.01). In addition, LZ maintained normal sAGE in normal rats infused with AGE-BSA, as it doubled the urinary AGE (uAGE) clearance (p < 0.01). B) LZ stimulated the uptake and degradation of (125) I-labeled AGE-BSA and (25) I-human serum AGE by Mf, while suppressing AGE-induced TNFalpha and IGF-I production. In MC, LZ suppressed the AGE-promoted PDGF-B, alpha1 type IV collagen, and tenascin mRNA levels, and restored the AGE-suppressed expression and activity of MMP-9, but not MMP-2. CONCLUSION: LZ may act to: a) accelerate renal in-vivo AGE clearance, b) suppress macrophage and mesangial cell- specific gene activation in vitro, and c) improve albuminuria due to diabetes. These data suggest that LZ by sequestering AGEs may protect against diabetic renal damage.

Animals↗

PubMed2001

[Determination and significance of serum markers for fibrosis in patients with chronic hepatitis].

OBJECTIVE: To find the relationship between serum levels of hyaluronic acid (HA), type III procollagen (PC III), laminin (LN), type IV collagen (IV-C) and hepatic fibrosis as well as to determine their value in clinical practice. METHODS: 2600 serum samples from chronic hepatitis patients were tested with RIA for fibrosis indexes assays including HA, PC III, LN and IV-C. 280 of the patients with serum samples taken had liver biopsy performed and the biopsy material was examine pathomorphologically. Fibrosis indexes were compared according to inflammation grade, fibrosis stage and chronic hepatitis degree. RESULTS: In the 2600 serum samples from chronic hepatitis patients, fibrosis indexes (including HA, PC III, LN and IV-C) had significant correlation with inflammation grade, fibrosis stage and the degree of chronic hepatitis (P < 0.01). The relating indexes to HA were 0.544, 0.548, 0.468 respectively, to PC III 0.495, 0.424, 0.335 respectively, to LN 0.214, 0.204, 0.184 and to IV-C were 0.464, 0.404, 0.412 respectively. CONCLUSION: Serum fibrosis indexes are fairly well correlated with the inflammation grade, fibrosis stage and the degree of chronic hepatitis. However, as diagnostic markers, they must be combined with liver function, ultrasonography and clinical features.

Adolescent↗

PubMed2001

[The effects of sodium butyrate on proliferation, differentiation and apoptosis in immortalized esophageal epithelial cells].

OBJECTIVE: To study the effects of sodium butyrate on proliferation, differentiation and apoptosis of immortalized esophagus epithelial cells. METHODS: SHEE, an immortalized human fetal esophageal epithelial cell line induced by HPV18 E6E7, was cultivated in culture flasks and 24-well plates. Two experiment groups of cultured cells were treated with 1 and 5 mmol/L of sodium butyrate respectively for 4 days, and one group of untreated cells set aside as control. The numbers of cloned cells were calculated. The ultra-structure of SHEE cells was examined by transmission electron microscopy (TEM). The cell cycle and number of apoptotic cells were measured by flow cytometry, Ki-67 and cytokeratin of cells were detected by immunohistochemistry method and F-actin of cells labeled with phalloidin was examined by laser confocal scanning microscopy. RESULTS: Colony formations showed a significant decrease in the 2 experiment groups after 4 days of culture (P < 0.01). In the 1 mmol/L group, the cells at S phase were diminished and arrested at G(0)/G(1) phase. Compared with control group, Ki-67 positive cells were found decreased, while F-actin and cytokeratin were increased. Apoptotic cells in 5 mmol/L group were increased markedly. CONCLUSIONS: Sodium butyrate may induce SHEE cells growth arrest, differentiation and apoptosis. The effects depend on sodium butyrate concentration and time of exposure. Whether it can be used in combination with other anticancer drugs should be further studied.

Actins↗