Biomedical subjects

Feng Zhou

Publications and source records attributed to Feng Zhou.

At least 55 records · Page 3Linked to original sources

PubMed2005

Experience in diagnosis and treatment of bleeding complications in severe acute pancreatitis by TAE.

The experience in diagnosis and treatment of bleeding complications in severe acute pancreatitis (SAP) by transcatheter arterial embolization was summarized. The clinical data of 19 SAP patients complicated with intra-abdominal bleeding in our hospital from Jan. 2000 to Jan. 2003 were analyzed retrospectively and the therapeutic outcome of TAE was evaluated statistically. The results showed that the short-term successful rate of hemostasis by TAE was 89.5% (17/19), the incidence of re-bleeding after TAE was 36.8% (7/19) and the successful rate of hemostatis by second TAE was 71.4% (5/7). It was concluded that the intra-abdominal bleeding in SAP was mainly caused by the rupture of erosive/infected pseudoaneurysm. Mostly, the broken vessels were splenic artery and gastroduodenal artery; In terms of emergence hemostatis, TAE is the most effective method. Surgical hemostasis is necessary if hemostasis by TAE is failed or re-bleeding occurs after TAE.

Adult↗

PubMed2005

[The voice analysis of subtotal laryngectomy by pedicled flaps reconstruction of vocal cord].

OBJECTIVE: To compare the voice quality of patient's after surgery over one year between the reconstruction of laryngeal function in subtotal laryngectomy by pedicled flaps and other laryngeal function in subtotal laryngectomy. METHOD: By using Dr Speech's acoustic analysis software, the noise level of the testing room was controlled under 45 dB. Before testing, patients have pronounced training. The testing voice was selected as[ae]. The evaluation parameters were jitter, shimmer, and NNE. RESULT: All the acoustic parameters of the reconstruction of laryngeal function in subtotal laryngectomy by pedicled flaps were increased distinctly than normal. There were statistical significant differences; compared with those by subtotal laryngectomy, the parameters decreased distinctly, and the voice quality improved distinctly. CONCLUSION: The reconstruction of laryngeal function in subtotal laryngectomy by pedicled flaps improve the voice quality, the acoustic analysis can be a measurable data of the postoperative voice quality evaluation, and administer to its objective evaluation.

Adult↗

PubMed2005

[An 1-year prospective cohort study on mortality of injecting drug users].

OBJECTIVE: To study the mortality among injecting drug users (IDUs) from an IDUs cohort in Liangshan of Sichuan province. METHODS: In November 2002, 376 injecting drug users were recruited and followed up for 1 year as part of a prospective cohort study. Socio-demographics and risk behaviors on drug use were recorded. After one year, the mortality rate was estimated and risk factors for mortality were analyzed using Cox regression. RESULTS: Out of the original cohort of 376 participants, there were 28 reported and confirmed deaths during the one year follow-up period. The mortality rate of the cohort was 77.32 per 1000 person-years (95% CI: 48.68 - 105.95) with the standardized mortality ratio (SMR) as 47.62 (95% CI: 31.63 - 68.71). Out of the 28 deaths, 64.3% (18/28) caused by overdoses of drug. No variables were found to be associated with death of all causes, but being un-married and >or= 9 year history of injecting drugs were found to be associated with overdose-related mortality in the final model of Cox regression. The hazard ratios were 4.51 (95% CI: 1.03 - 19.67) and 2.77 (95% CI: 1.10 - 7.00) respectively. CONCLUSION: Overdose served the most frequent cause of deaths in Liangshan of Sichuan province. Future studies should be conducted to focus on mortality and risk factors associated with mortality among IDUs to provide targeted interventions in reducing unnatural mortality.

Adult↗

PubMed2005

[Expression and significance of EBV LMP2A in nasopharyngeal cancer specimens].

OBJECTIVE: To investigate the expression of Epstein-Barr Virus (EBV) latent membrane protein 2A (LMP2A) in tumor tissues of nasopharyngeal cancer (NPC) and discuss the possibility (feasibility) that LMP2A was selected (to select LMP2A ) as a target antigen in immunologic treatment of NPC. METHOD: The expression of EBV LMP2A was detected in the specimens of 40 patients with NPC and 38 cases with nasopharyngeal inflammation by S-P immunohistochemical methods. RESULT: Of the 40 NPC specimens, 36 cases expressed LMP2A. There was no significant relationship between the expression of LMP2A and the histological differentiation of NPC. Thirty-three of the 38 cases with nasopharyngeal inflammation showed negative expression of LMP2A. There was a significant difference of LMP2A expression between NPC and nasopharyngeal inflammation. CONCLUSION: The expression of EBV LMP2A is confirmed in the NPC specimens,and the negative results are seen in the majority of the inflammation cases. There is a possibility of applying LMP2A target antigen to induce specific immunoreaction to kill tumor cells of NPC.

Adolescent↗

PubMed2005

[Value of multislice spiral CT scanning and three-dimensional reconstruction in selecting optimal length and shape of mandible internal fixation material].

OBJECTIVE: To investigate the value of multislice spiral CT (MSCT) scanning and three-dimensional reconstruction in selecting optimal length and shape of mandible internal fixation material. METHODS: Three-dimensional reconstruction of the mandible was performed in 5 cases by MSCT scanning and the length of the mandible for operation was measured. Some isometric points were chosen on the mandibular curve and the distance from these points to the two ends of the curve was measured to depict the mandibular curve using a self-designed skeletal curve-depicting software. The optimal length and shape of the material for internal fixation was then determined. RESULTS: After removal of the soft tissues and other irrelevant bones from the reconstructed three-dimensional mandible with clear view from any directions, the length of the mandible was accurately measured with the software. The physiological curve of the mandible was generated after determination of the distances from the chosen points on the mandibular curve and to the two ends of the curve for precise determination of the length and shape of the material for internal fixation. CONCLUSION: Three-dimensional mandible reconstruction with MSCT and measurement facilitates the determination of the optimal length and shape of the internal fixation material to enhance the attachment between the material and the bone surface and consequently the therapeutic effects.

Adolescent↗

PubMed2004

Inhibition of tumor necrosis factor alpha secretion and prevention of liver injury in ethanol-fed rats by antisense oligonucleotides.

Elevated serum tumor necrosis factor alpha (TNF-alpha) levels predict mortality in patients with alcoholic liver disease. Administration of anti-TNF-alpha antibodies, obliteration of Kupffer cells or gut sterilization protect against ethanol-induced hepatocellular injury in animal models. In this study, we evaluated the in vivo efficacy of an antisense phosphorothioate oligodeoxynucleotide (S-ODN) targeted against TNF-alpha mRNA (TJU-2755). Naive rats that were administered TJU-2755 (10 mg/(kg body weight (BW)/day) for 2 days) in the free form were challenged with LPS to induce TNF-alpha secretion. Antisense TJU-2755 treatment reduced serum TNF-alpha levels by 62%. A comparison of the efficacies of mismatched and random S-ODNs with that of TJU-2755 showed that some non-specific inhibition might accompany the sequence-specific effects of TJU-2755. To optimize the targeting of the S-ODN, TJU-2755 was encapsulated in pH-sensitive liposomes for in vivo delivery to macrophages. The efficacy of liposome-encapsulated TJU-2755 was assessed in ethanol-fed animals that were administered LPS to induce liver injury. Liposomal delivery of TJU-2755 allowed a much lower dose (1.9 mg/kg BW/day, for 2 days) of the S-ODN to reduce LPS-induced serum TNF-alpha (by 54%) and liver injury (by 60%) in ethanol-fed rats. These data indicate that liposome-encapsulated S-ODNs targeted against TNF-alpha have therapeutic potential in the treatment of alcoholic liver disease.

Animals↗

PubMed2004

Pharmacokinetic model-predicted anticancer drug concentrations in human tumors.

In an era when molecular and targeted anticancer therapeutics is a major focus and when understanding drug dynamics in tumor is critical, it seems advantageous to be able to relate drug concentrations in tumors to corresponding biological end points. To that end, a novel method, based on physiologically based hybrid pharmacokinetic models, is presented to predict human tumor drug concentrations. Such models consist of a forcing function, describing the plasma drug concentration-time profile, which is linked to a model describing drug disposition in tumors. The hybrid models are originally derived from preclinical data and then scaled to humans. Integral to the scale-up procedure is the ability to derive human forcing functions directly from clinical pharmacokinetic data. Three examples of this approach are presented based on preclinical investigations with carboplatin, topotecan, and temozolomide. Translation of these preclinical hybrid models to humans used a Monte Carlo simulation technique that accounted for intrasubject and intersubject variability. Different pharmacokinetic end points, such as the AUC tumor, were extracted from the simulated human tumor drug concentrations to show how the predicted drug concentrations might be used to select drug-dosing regimens. It is believed that this modeling strategy can be used as an aid in the drug development process by providing key insights into drug disposition in tumors and by offering a foundation to optimize drug regimen design.

Animals↗

PubMed2004

Determination of vincristine in mouse plasma and brain tissues by liquid chromatography-electrospray mass spectrometry.

Vincristine is an anticancer agent that continues to be examined in preclinical models even though it is used in a variety of human neoplastic disorders. We developed a sensitive liquid chromatography-mass spectrometry (LC-MS) method for the determination of vincristine in plasma and in brain tissues that would support investigations on drug distribution into tissues in animal models. The procedure required only a small sample volume (10 microl) of plasma, which circumvented a limitation of most other assays that were developed for human samples. A solid-phase extraction procedure was employed that enabled the eluent to be directly injected onto a reversed-phase chromatographic HPLC system using positive electrospray ionization followed by mass spectrometric detection. The extraction recoveries of vincristine were 57 and 60% from plasma and brain tissues, respectively. The mobile phase consisted of methanol and 15 mM ammonium acetate in 0.02% formic acid (70:30) that was pumped at 0.2 ml/min to yield retention times of 1.6 and 1.8 min for vincristine and vinblastine, the internal standard, respectively. The method was validated at vincristine plasma concentrations from 0.01 to 2 microg/ml, and from 0.01 to 1 microg/g in brain tissue. The advantage of the method enabled the quantitation of vincristine in multiple plasma samples obtained from a single mouse, which permitted the accurate estimation of its pharmacokinetic properties.

Animals↗

PubMed2004

Influence of serum from liver-damaged rats on differentiation tendency of bone marrow-derived stem cells.

AIM: Recent studies in both rodents and humans indicated that bone marrow (BM)-derived stem cells were able to home to the liver after they were damaged and demonstrated plasticity in becoming hepatocytes. However, the question remains as to how these stem cells are activated and led to the liver and where the signals initiating the mechanisms of activation and differentiation of stem cells originate. The aim of this study was to investigate the influence of serum from liver-damaged rats on differentiation tendency of bone marrow-derived stem cells. METHODS: Serum samples were collected from rats treated with a 2-acetylaminofluorene (2-AAF) /carbon tetrachloride (CCl(4)) program for varying time points and then used as stimulators of cultured BM stem cells. Expression of M(2)- and L-type isozymes of rat pyruvate kinase, albumin as well as integrin-beta1 were then examined by reverse transcription polymerase chain reaction (RT-PCR) to estimate the differentiation state of BM stem cells. RESULTS: Expression of M(2)-type isozyme of pyruvate kinase (M(2)-PK), a marker of immature hepatocytes, was detected in each group stimulated with experimental serum, but not in controls including mature hepatocytes, BM stem cells without serum stimulation, and BM stem cells stimulated with normal control serum. As a marker expressed in the development of liver, the expression signal of integrin-beta1 was also detectable in each group stimulated with experimental serum. However, expression of L-type isozyme of pyruvate kinase (L-PK) and albumin, marker molecules of mature hepatocytes, was not detected in groups stimulated with experimental serum. CONCLUSION: Under the influence of serum from rats with liver failure, BM stem cells begin to differentiate along a direction to hepatocyte lineage and to possess some features of immature hepatocytes.

Animals↗

PubMed2004

Community-based survey of HCV and HIV coinfection in injection drug abusers in Sichuan Province of China.

AIM: To investigate the prevalence and risk factors of HCV/HIV coinfection in injection drug abusers (IDAs) in Lianshan Yi Autonomous Prefecture of Sichuan province, China. METHODS: From November 8, 2002 to November 29, 2002, a community-based survey was conducted to investigate the demographic characteristics, patterns of shared injectors devices and sexual behaviors in IDAs. Blood samples were also collected to test HCV and HIV infection. A total of 379 subjects were recruited in the study through community outreach and peer recruiting methods. RESULTS: Of the 379 IDAs, the HCV prevalence and HIV prevalence were 71.0% and 11.3%, respectively, and HCV/HIV coinfection was 11.3%. HCV infection was found in 100% and 67.3% of HIV-positive and HIV-negative IDAs, respectively. HIV prevalence was 16.0% in HCV positive IDAs while none of the HCV negative IDAs was positive for HIV. Ethnicity, shared needles or syringes and cotton in the past 3 mo and syphilis infection were associated with HCV/HIV coinfection shown by univariate analysis using chi-square test. Multivariate logistic regression analysis showed that shared needles or syringes in the past 3 mo (Odds ratio=3.121, 95% CI: 1.278-7.617, P<0.05) and syphilis infection (Odds ratio=2.914, 95% CI: 1.327-6.398, P<0.01) were significantly associated with HCV infection. No statistically significant association was found in univariate analysis between sexual behaviors and HCV/HIV coinfection. CONCLUSION: Shared needles and syringes in the past 3 mo and syphilis infection were significantly associated with HCV infection. Further sero-epidemiological prospective cohort studies should be conducted to clarify the impact of syphilis and high risk sexual behaviors on HCV transmission through unprotected sexual intercourse.

Adult↗

PubMed2004

Protein characterization by on-line capillary isoelectric focusing, reversed-phase liquid chromatography, and mass spectrometry.

Two-dimensional polyacrylmide gel electrophoresis (2D-PAGE), perhaps the most widely used method in proteomics research, is often limited by sensitivity and throughput. Capillary isoelectric focusing (CIEF) coupled with electrospray ionization (ESI) mass spectrometry (MS) provides a liquid-based alternative to 2D-PAGE that can overcome these problems but is limited by ampholyte interference and signal quenching in ESI-MS. Inserting a reversed-phase liquid chromatography (RPLC) step between CIEF and MS can remove this interference. In this work, a CIEF-RPLC-MS system is described for separation and characterization of proteins in complex mixtures. CIEF is performed with a microdialysis membrane-based cathodic cell that also permits protein fractions to be collected, washed to remove ampholyte, and analyzed by RPLC-MS. CIEF performance with this cell is equivalent to that achieved with a conventional cathodic cell, and no loss of protein is observed during faction collection. The cell can be easily and safely retrofitted into commercial instrumentation and is applicable for peptide analysis as well. Protein detection at the low-femtomole level is demonstrated with little or no interference from ampholyte, and CIEF-RPLC-MS data are used to construct a plot of pI vs MW for a protein mixture. The current instrumental configuration allows seven fractions in the pI range 3-10 to be analyzed by RPLC-MS in 2 h.

Chromatography, Liquid↗

PubMed2004

Effect of early hemofiltration on pro- and anti-inflammatory responses and multiple organ failure in severe acute pancreatitis.

The effects of early hemofiltration on the serum levels of cytokines, pro- and anti-inflammatory balance and organ function in pigs with severe acute pancreatits (SAP) were studied. SAP pig model was induced by retrograde injection of artificial bile into the pancreatic duct. The pigs were randomly divided into SAP hemofiltration treatment group (HF group, n=8) and SAP non-hemofiltration treatment group (NHF group, n=8). In the HF group, the animals were subjected to high-volume and zero-balance hemofiltration therapy. The results showed that as compared with NHF group, MAP, CVP and PaO2/FiO2 were significantly increased (P<0.01), while HR, urinary protein content, serum ALT level, pulmonary coefficient and lung wet/dry ratio obviously decreased (P<0.05) in HF group. Under a light microscope, the pulmonary histologic scoring was lower that in HF group (P<0.01) and the lesions of renal and liver tissues were milder. However, there was no significant difference in the pancreatic histologic scoring between the two groups. Six h after establishment of the model, the serum levels of TNF-alpha, IL-1beta were lower, while the IL-10/ TNF-alpha ratio was higher in HF group (all P<0.05). It was suggested that early hemofiltration could effectively remove the serum cytokines TNF-alpha and IL-1beta in SAP pigs, elevate the ratio of IL-10/TNF-alpha, improve hemodynamics and alleviate the lesions of lung, kidney and liver tissues.

Animals↗

PubMed2004

PDX-1 expression in pancreatic ductal cells after partial pancreatectomy in adult rats.

To investigate the protein and mRNA expression of pancreas/duodenal homeobox-1 (PDX-1), a transcription factor as a marker for pancreatic stem cells, in pancreatic ductal cells of rats after partial (90%) pancreatectomy and evaluated the significance of the PDX-1 expression. Western blot and Reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect the expression of PDX-1 protein and mRNA respectively. PDX-1 protein was only faintly detected in pancreatic ductal cells on the day 1 after partial pancreatectomy. On the day 2 and 3 after operation in operation group, a 2-3 fold increased PDX-1 protein was observed, corresponding to the characteristic 42-kD protein in Western blot. There was significant difference between operation group and sham-operation group (P<0.05). PDX-1 protein expression on the day 5 and 7 after operation had already been no difference from control group (P>0.05). RT-PCR revealed the PDX-1 mRNA expression showed no significant difference between operation group at various time points and sham-operation group (P> 0.05). These results indicate that there was overexpression of PDX-1 in the cells of pancreatic epithelium during the regeneration of remnant pancreas after partial pancreatectomy in adult rats, suggesting the pancreatic stem cells in pancreatic ductal epithelial cells are involved in the regeneration of remnant pancreas and the expression of PDX-1 in ductal cells was regulated posttranscription.

Animals↗

PubMed2004

Generating protein sequence tags by combining cone and conventional collision induced dissociation in a quadrupole time-of-flight mass spectrometer.

The goal of proteomics research is to be able to identify and quantify the vast numbers of proteins within an organism or tissue. "Top-down" methods address this goal without the need for proteolytic digestion prior to mass analysis. We report here an approach for top-down protein identification that has been implemented on a commercially available, unmodified Qq-TOF mass spectrometer. Intact protein molecular ions first undergo cone fragmentation in the electrospray inlet. Conventional MS/MS is then performed on a mass selected cone fragment using CID in the Qq interface of the Qq-TOF mass spectrometer to generate a sequence tag through a pseudo-MS3 experiment. Seven proteins varying in molecular weight between 11 and 66 kDa were chosen to demonstrate applicability of method. After the molecular weight of the intact protein was determined, the cone voltage was varied to induce fragmentation. Cone fragment ions were then further dissociated using conventional CID, and the resulting MS/MS spectra were processed and analyzed for sequence tags. Sequence tags were easily identified from a MS/MS spectrum of a cone induced fragment ion both manually and through a de novo sequencing program included in the software associated with the mass spectrometer. Sequence tags were subjected to database searching using the PeptideSearch program of EMBL, and all protein sequence tags gave unambiguous search results. In all cases, sequence tags were found to originate from the n- and/or c-termini of the proteins.

Amino Acid Sequence↗

PubMed2004

Community-based survey of HIV transmission modes among intravenous drug users in Sichuan, China.

GOAL: The goal of this study was to investigate the prevalence and different transmission risk factors of HIV among intravenous drug users (IDUs) in the Liangshan Yizu Autonomous Region of Sichuan province, China. METHODS: From November 8, 2002, to November 29, 2002, a community-based survey was conducted to investigate demographic characteristics, sharing patterns of injection equipment, frequencies of injection equipment, and sexual behaviors in IDUs. Blood samples were also collected to test for HIV and syphilis infection. A total of 379 subjects were recruited for the study through community outreach and peer recruiting methods. RESULTS: Of 379 IDUs, HIV prevalence was 11.3% (43 of 379). Ethnicity, total times of shared injection equipment in the past 3 months, shared cotton in the past 3 months, and syphilis infection were associated with HIV infection after univariate analysis using the chi-squared test. Multivariate logistic regression analysis showed total times of sharing injection equipment in the past 3 months (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.18-4.43) and syphilis infection (OR, 3.10; 95% CI, 1.48-6.48) in the final model were independently associated with HIV prevalence. CONCLUSION: The results of this study suggested total times of sharing injection equipment in the past 3 months and syphilis infection were significantly associated with HIV infection. Further seroepidemiologic prospective cohort studies should be conducted to clarify the impact of syphilis and high-risk sexual behaviors on HIV transmission through unprotected sexual intercourse.

Adolescent↗

PubMed2004

Short-term episodic memory for visual textures: a roving probe gathers some memory.

Cognition is shaped by the way that past experiences are represented in memory. To examine the representation of recent visual experiences, we devised a novel procedure that measures episodic recognition memory for synthetic textures. On each trial, two brief study stimuli were followed by a probe, which either replicated one of the study stimuli or differed in spatial frequency from both. The probe's spatial frequency roved from trial to trial, testing recognition with a range of differences between probe and study items. Repeated testing of recognition generated mnemometric functions, snapshots of memory strength's distribution. The distributional characteristics of the mnemometric functions rule out several hypotheses about memory representation, including the hypothesis that representations are prototypes constructed from previously seen stimuli; instead, stimuli are represented in memory as noisy exemplars.

Adult↗

PubMed2004

[Multiple auditory steady-state evoked responses test of young adults with normal hearing].

OBJECTIVE: To determine the threshold of multiple auditory steady-state evoked responses(ASSR) of young adults with normal hearing, and to offer essential diagnosticate datas. METHOD: ASSR were examined in 22 (44 ears) young adults with normal hearing. There were 11 men and 11 women in 22 young adults. RESULT: Average threshold of ASSR were about 40 to 60 dBHL between 0.25-8.0 kHz, and they became higher from low frequency to high frequency. Average threshold of MFSSR were 40 dBHL at 0.25-0.5, 1 kHz, and about 45 dB HL at 2 kHz, and about 50 dB HL at 4 kHz, and about 60 dB HL at 8 kHz. Difference values were about 25 to 55 dB HL between average threshold values of ASSR and hearing, and they became higher from low frequency to high frequency, those were about 25 dBHL at 0.25 kHz, about 30 dBHL at 0.5 kHz, about 35 dBHL at 1 kHz, about 40 dB HL at 2 kHz, about 50 dB HL at 4 kHz, about 55 dBHL at 8 kHz. CONCLUSION: There is a definite numeral value between threshold of ASSR and hearing in young adults with normal hearing. Pure tone hearing threshold can be conferred by examining the threshold of ASSR and by using the definite numeral values.

Audiometry, Evoked Response↗

PubMed2004

[Epidemiological study on traffic accident in Shanghai from 2000 to 2002].

OBJECTIVE: Data on traffic accident from year 2000 to 2002 were collected and testified. Epidemiological study was carried out to find the main risk factors of traffic accident. METHODS: The spatial distribution was conducted by means of Geographic Information System (GIS) and were marked on Shanghai digitalized map with different layers by different colors. RESULTS: Results showed that during 2000, 2001 and 2002, 69,669 , 68,894, and 47,088 traffic accident episodes occurred in Shanghai, resulting in 1747, 1724, 1557 deaths respectively with direct economic lost: 2.1, 2.4, 3.0 billion RMB. The main risk factors causing traffic accident deaths would include drinking alcohol before driving, fatigue and speeding. The leading causes of death were head injury and complex injury of body. GIS showed that there was a homocentric circle with more traffic accidents in downtown city, but more deaths in the urban city. Disease burden caused by traffic accident was very heavy. CONCLUSION: In Shanghai, traffic accident has great impact on social and economic issues thus should be controlled effectively. Focus should be layed on control of traffic accident in downtown area and to decrease the number of deaths related to traffic accident in the urban area.

Accidents, Traffic↗