Biomedical subjects

Dayu Liu

Publications and source records attributed to Dayu Liu.

At least 19 recordsLinked to original sources

PubMed2006

Isotachophoresis preconcentration integrated microfluidic chip for highly sensitive genotyping of the hepatitis B virus.

The genotyping of hepatitis B virus (HBV) has become recently a valuable tool not only for epidemiological reasons but also for the clinical practice. Conventional methods for HBV genotyping typically include amplification of the target DNA sequences with a two-round nested PCR followed by separation of the amplified fragments by gel electrophoresis. A microfluidic chip that couples isotachophoresis (ITP) preconcentration and zone electrophoresis (ZE) separation may provide great advantages for sensitive, rapid and cost-effective clinical analysis. In this study, an HBV genotyping method with only one amplification round was developed by the application of the ITP-ZE chip. All the analysis steps of the ITP-ZE separation including sample injection, stacking and separation were performed continuously, controlled by sequential high-voltage switching. A 2.1cm sample plug was preconcentrated between discontinuous buffers in ITP process, followed by ZE separation. Sensitivity enhancement was obtained through the increase of sample loading volume. The average LOD value of the ITP-ZE microfluidic chip was determined to be 0.0021pg/muL. In a large-scale HBV genotyping test, single round PCR products were analyzed by ITP-ZE microfluidic chip, and the results were compared with that of the conventional method. Among the 200 cases studied, the classification rate obtained with microfluidic chip was 93%, which was 6% higher than that obtained with the conventional method. Method with ITP-ZE chip analysis provides HBV genotyping information in reduced PCR amplification time with higher detection rate when compared with conventional method. This method holds great potential for extrapolation to the abundance of similar molecular biology-based techniques in clinical diagnosis.

Base Sequence↗

PubMed2006

Parallel analysis of biomolecules on a microfabricated capillary array chip.

This paper focused on a self-developed microfluidic array system with microfabricated capillary array electrophoresis (mu-CAE) chip for parallel chip electrophoresis of biomolecules. The microfluidic array layout consists of two common reservoirs coupled to four separation channels connected to sample injection channel on the soda-lime glass substrate. The excitation scheme for distributing a 20 mW laser beam to separation channels in an array is achieved. Under the control of program, the sample injection and separation in multichannel can be achieved through six high-voltage modules' output. A CCD camera was used to monitor electrophoretic separations simultaneously in four channels with LIF detection, and the electropherograms can be plotted directly without reconstruction by additional software. Parallel multichannel electrophoresis of series biomolecules including amino acids, proteins, and nucleic acids was performed on this system and the results showed fine reproducibility.

Amino Acids↗

PubMed2006

Integration of nanoporous membranes for sample filtration/preconcentration in microchip electrophoresis.

Microfluidic devices integrating membrane-based sample preparation with electrophoretic separation are demonstrated. These multilayer devices consist of 10 nm pore diameter membranes sandwiched between two layers of PDMS substrates with embedded microchannels. Because of the membrane isolation, material exchange between two fluidic layers can be precisely controlled by applied voltages. More importantly, since only small molecules can pass through the nanopores, the integrated membrane can serve as a filter or a concentrator prior to microchip electrophoresis under different design and operation modes. As a filter, they can be used for separation and selective injection of small analytes from sample matrix. This has been effectively applied in rapid determination of reduced glutathione in human plasma and red blood cells without any off-chip deproteinization procedure. Alternatively, in the concentrator mode, they can be used for online purification and preconcentration of macromolecules, which was illustrated by removing primers and preconcentrating the product DNA from a PCR product mixture.

DNA↗

PubMed2005

Simultaneous and ultrarapid determination of reactive oxygen species and reduced glutathione in apoptotic leukemia cells by microchip electrophoresis.

A microchip electrophoresis method coupled with laser-induced fluorescence (LIF) detection was established for simultaneous determination of two kinds of intracellular signaling molecules (reactive oxygen species, ROS, and reduced glutathione, GSH) related to apoptosis and oxidative stress. As the probe dihydrorhodamine-123 (DHR-123) can be converted intracellularly by ROS to the fluorescent rhodamine-123 (Rh-123), and the probe naphthalene-2,3-dicarboxaldehyde (NDA) can react quickly with GSH to produce a fluorescent adduct, rapid determination of Rh-123 and GSH was achieved on a glass microchip within 27 s using a 20 mM borate buffer (pH 9.2). The established method was tested to measure the intracellular ROS and GSH levels in acute promyelocytic leukemia (APL)-derived NB4 cells. An elevation of intracellular ROS and depletion of GSH were observed in apoptotic NB4 cells induced by arsenic trioxide (As(2)O(3)) at low concentration (1-2 microM). Buthionine sulfoximine (BSO), in combination with As(2)O(3) enhanced the decrease of reduced GSH to a great extent. The combined treatment of As(2)O(3) and hydrogen peroxide (H(2)O(2)) led to an inverse relationship between the concentrations of ROS and GSH obtained, showing the proposed method can readily evaluate the generation of ROS, which occurs simultaneously with the consumption of the inherent antioxidant.

Apoptosis↗

PubMed2005

[The synthesis treatment of tonsillar cancer].

OBJECTIVE: To study the synthesis treatment of tonsillar cancer. METHOD: From 1987 to 1999, thirty four patients with tonsillar cancer were treated with surgery and postoperative radiotherapy. There were 21 males and 13 females and the ages ranged from 33-74. According to TNM staging system, there are 5 stage I , 6 stage 11, 9 stage II and 14 stage IV. According to conditions, the transoral approach, mandibular wing approach and transhyoid approach were choiced to resect the tumor. Surgical defect was repaired by myocutaneous flap, tongue flap, or softpalate flap. RESULT: The 5 year survival rate were 68.8% and local control 76.4%. Function of chewing, deglutition and speech were restored well. CONCLUSION: The treatment of surgery and postoperative radiotherapy can improved the survival rate, local control rate and quality of life of patients.

Adult↗

PubMed2005

[Serum levels and clinical values of soluble intercellular adhesion molecule-1 in patients with nasal polyps].

OBJECTIVE: To assess the role of soluble intercellular adhesion molecule-1 (sICAM-1) in etiology of nasal polyps. METHOD: Twenty-nine patients with nasal polyps and 20 healthy control cases were chosen. Their serum sICAM-1 was determined by a sandwich enzyme-linked immunosorbent assay (ELISA). All patients were treated by glucocorticoid, serum sICAM-1 was determined post-treatment again. RESULT: (1) Serum levels of sICAM-1 in patients with nasal polyps were higher than that of control group: (2) Serum levels of sICAM-1 in patients were reduced after glucocorticoid treatment, the decrease of sICAM-1 was more apparent in evident-effect group than in effect group; (3) There was a close correlation between the decrease of polyp-size scores and the decrease of serum sICAM-1. CONCLUSION: The elevated expressions of sICAM-1 in patients with nasal polyps indicate its important role in eosinophil recruitment, which was considered as a representative hallmark for nasal polyps. The sICAM-1 is down-regulated by systemic and topical glucocorticoid treatment and the decrease of sICAM-1 is correlated with clinical effect. To take these lines of evidence together, anti-adhesion therapy may be effective for nasal polyps, serum sICAM-1 levels may be use to monitor the effect of steroid therapy in nasal polyps.

Adolescent↗

PubMed2005

[The effect of sodium phenylbutyrate to agents used in induction chemotherapy on laryngeal carcinoma cells Hep-2 in vitro].

OBJECTIVE: To study the effect of sodium phenylbutyrate when it combined with agents used in induction chemotherapy on laryngeal carcinoma cells Hep-2 in vitro. METHOD: MTT were used to examine the growth inhibition of Hep-2 cells treated by the combination of PB with 5-FU or CDDP in vitro. RESULT: When 5-FU or CDDP combined with PB respectively, there was significantly difference between every two dose groups of the two agents or every dose group and control group ( P < 0.05). When the dosage of 5-FU or CDDP was definition,there was significantly difference between every two dose groups of PB ( P < 0.05). CONCLUSION: PB could enhance the cytotoxic effects of agents used in induction chemotherapy on laryngeal carcinoma cells Hep-2 in vitro, which showed the possibility in reinforcement the treatment effect and reduction the occurrence of the complication and toxic reaction of induction chemotherapy on laryngeal carcinoma.

Antineoplastic Agents↗

PubMed2004

Determination of SARS-coronavirus by a microfluidic chip system.

We have developed a new experimental system based on a microfluidic chip to determine severe acute respiratory syndrome coronavirus (SARS-CoV). The system includes a laser-induced fluorescence microfluidic chip analyzer, a glass microchip for both polymerase chain reaction (PCR) and capillary electrophoresis, a chip thermal cycler based on dual Peltier thermoelectric elements, a reverse transcription-polymerase chain reaction (RT-PCR) SARS diagnostic kit, and a DNA electrophoretic sizing kit. The system allows efficient cDNA amplification of SARS-CoV followed by electrophoretic sizing and detection on the same chip. To enhance the reliability of RT-PCR on SARS-CoV detection, duplex PCR was developed on the microchip. The assay was carried out on a home-made microfluidic chip system. The positive and the negative control were cDNA fragments of SARS-CoV and parainfluenza virus, respectively. The test results showed that 17 positive samples were obtained among 18 samples of nasopharyngeal swabs from clinically diagnosed SARS patients. However, 12 positive results from the same 18 samples were obtained by the conventional RT-PCR with agarose gel electrophoresis detection. The SARS virus species can be analyzed with high positive rate and rapidity on the microfluidic chip system.

Autopsy↗

PubMed2004

[Small partial laryngectomy for early-stage glottic carcinoma].

OBJECTIVE: To explore the surgery way for T1, T2 glottic carcinoma. METHOD: Small partial laryngectomy were performed to 112 patients with T1, T2 (T1 N0 M0, T2 N0 M0) glottic carcinoma. The surgery method, effect and treatment advantage was summarized and compared with laser therapy and radiotherapy, the dynamic follow-up of arytaenoidea cartilage movement, glottidis rimae conformation and voice change was analyzed. The preoperative and postoperative voice quality was compared with the software of Dr. speech system for windows. RESULT: All incisions were healed one stage in 6 or 7 days, the mean time in hospital is 9.76 days; all patients took food with mouth after 2 or 3 days, all trachea cannula was removed successfully during in hospital, the mean time with cannula is 7.32 days and the rate of removing cannula 100%. Arytaenoidea cartilago movement of 47 cases 1 week after surgery weakened and gradually improved, glottidis rimae conformation is close to be normal after 2 months. There is no significant difference of Shimmer and NNE between preoperative and postoperative 1 week (P > 0.05), but there is a significant difference between preoperative and postoperative 2 months, half a year, and also is between postoperative 1 week and 2 months, half a year (P < 0.01). All 76 cases survive during 3 years' follow-up, 35 of 36 cases in 5 years' follow-up survive (1 case died without definite cause), and there is 2 cases for recurrence. CONCLUSION: Small partial laryngectomy can provide large operative view, resect the tumor completely, make diet and speech recover in shorter time and improve the voice quality, so the surgery is available.

Adult↗

PubMed2003

[Uni-pedicled sternohyoid myofascial flap reconstruction of the larynx for partial laryngectomy].

OBJECTIVE: To observe the appliance value of uni-pedicled sternohyoid myofascial flap in laryngeal function reconstruction after partial laryngectomy. METHOD: Forty patients who underwent partial laryngectomy from 1981 to 1999 were summarized(male 36 cases, female 4 cases). Among them 19 were supraglottic carcinomas (T2N0 6, T2N2 1, T3N0 2, T3N1 1, T3N2 2, T4N0 4, T4N1 1, T4N2 2), 19 cases were glottic carcinomas(T2N0 6, T3N0 11, T3N2 2), 2 cases were subglottic carcinomas(T2N0 1, T3N0 1). The choice of surgical procedure was decided on the pathologic conditions of the larynx, the laryngeal function was reconstructed using uni-pedicled sternohyoid myofascial flap. RESULT: Thirty-three cases were decannulated and recovered with laryngeal functions. The decannulation rate was 82.50%. All the patients rehabilitated deglutition in 10 to 20 days after surgery. None presented complication of aspiration. The 3-year survival rate was 86.58% and 5-year survival rate was 72.49%. CONCLUSION: The uni-pedicled sternohyoid myofascial flaps are appropriate for reconstruction of surgical defect in laryngeal carcinomas.

Adult↗

PubMed2003

[One stage reconstruction of larynx and cervical trachea involved by advanced thyroid carcinoma].

OBJECTIVE: To investigate clinical prognosis and the one-stage methods of reconstruction for advanced thyroid carcinoma while larynx and cervical trachea involved. METHOD: One-stage resection and laryngotracheal reconstruction were performed in 18 advanced thyroid carcinomas. Among them, total laryngectomy were performed in 3 cases and partial laryngectomy in the other 4 larynx-involved cases. Cervical trachea involvement were found in all 18 cases. Besides 8 shave-off of tumor, area of trachea invaded by carcinoma were removed in other 10 cases. The methods applied for the tracheal reconstruction were 1 simple suture, 3 tracheal anastomosis, 2 pedicled sternocleidomastoid myoperiosteous flap, 3 insular myocutaneous pectoralis major flap and 1 cervical flap. RESULT: One patient died of cancer reoccurrence while in the hospitalization. Except for 3 cases with total laryngectomy, larynx preservation were done in 14 cases and tracheal cannula were pulled out in 8, blocked in 2 and kept carrying in 4 cases. CONCLUSION: One stage reconstruction of larynx and cervical trachea involved by advanced thyroid carcinoma is feasible and practical. Curative rate, survival time and life quality all can be improved.

Adult↗

PubMed2003

[Preservative surgery of T3 glottic cancer: 75 cases report].

OBJECTIVE: To explore the methods of surgery and evaluate the long-term results of preservative surgery for T3 glottic cancer. METHOD: Seventy-five cases with T3 glottic cancer were treated surgically from 1989 to 1999. The lesions were removed entirely, the epiglottis, bi-pedicled myoperichondral flap, platysma myocutaneous flap, sternohyoid myofascial flap, platysma myofascial flap, thyroid perichondral flap were utilized to restore the defects of larynx and reconstruct the laryngeal functions. RESULT: The 3- and 5-year survival rates were 83.2% and 73.6% in all cases, 82.7% had all laryngeal functions (voice, respiration and deglutition) restored and 17.3% partially restored(voice and deglutition). CONCLUSION: Preservative surgery can be carried out for T3 glottic cancer with the lesions entirely removed. Choosing and following what is optimum from multiple feasible surgical methods is a prerequisite for better laryngeal functions.

Adult↗

PubMed2003

[Surgical management of stomal recurrence].

OBJECTIVE: To study effective treatment of stomal recurrence. METHOD: Thirty-one patients with stomal recurrence underwent surgical management. Twelve of them considered to have the probability of metastasis to regional lymphnodes underwent modified radical neck dissection. Twenty-five cases(I and II type) received complete tumor excision, but for III and IV type, only 50% (3/6) of the patients gained complete tumor excision. The surgical defects were repaired by pectoralis major myocutaneous flap in all the patients. RESULT: In 13 cases of type I, 7 cases had followed up for 3 years, 4 cases died, while in 12 cases of type II, 8 cases had followed up for 3 years, 5 cases died. Survival remains poor for III or IV type. Most of them died within 3 years after operation. The complication rate of pharyngeal fistula and pneumatothorax was 12.9% and 9.7%, respectively. CONCLUSION: The overall prognosis of stomal recurrence is dismal. A proper surgical treatment in some cases will prolong the lifetime and improve their quality of life.

Adult↗

PubMed2002

[Surgical management of laryngeal cancer and preservation of laryngeal function].

OBJECTIVE: To explore the surgical methods for laryngeal cancer and long-term effects of larygectomy. METHODS: 625 cases of laryngeal cancer at different stages, including 182 cases of supraglottic cancer, 429 cases of glottic cancer, and 14 cases of subglottic cancer, underwent operation of different kinds from 1979 to 1999. Radiotherapy was given to those with poorly differentiated squamous carcinoma or with metastasis of cervical lymph nodes postoperatively. The effects of operation, especially that on the preservation of laryngeal function was analyzed. RESULTS: Partial laryngectomy was performed on 521 of the 625 cases (83.4%) and 203 of the 305 cases at stages III and IV (66.6%). The decannulation rate was 84.07% in the cases undergoing partial laryngectomy. The nasal feeding tube was removed and peroral feeding was recovered in all patients. All cases undergoing partial laryngectomy succeeded in phonation. The overall 3-year survival rate was 89.63% and the overall 5-year survival rate was 77.36%. For the cases with laryngeal cancer at stages III and IV, the 3-year survival rate among those undergoing partial laryngectomy was 84.9%, not significantly different from that among those cases undergoing total laryngectomy (87.7%, P > 0.05); the 5-year survival rate was 66.6% among those undergoing partial laryngectomy and was 69.7% among those undergoing totals laryngectomy (P > 0.05). CONCLUSION: The rate of partial laryngectomy is rather high in this group. It is possible to preserve the laryngeal function without compromising the remote survival rate. The prerequisite for the preservation of laryngeal function is to master and choose the proper renovation methods.

Adult↗

PubMed2002

[Application of epiglottis in laryngeal reconstruction].

OBJECTIVE: To observe the application value of epiglottis in laryngeal reconstruction after partial laryngectomy. METHODS: The data of 168 patients, 25 with supraglottic carcinoma (T1N0 2, T2N0 10, T2N1 1, T2N2 1, T3N0 7, T3N2 1, T4N0 2, and T4N2 1), 140 with glottic carcinoma (T1N0 36, T1N1 1, T2N0 52, T2N1 1, T2N2 1, T3N0 40, T3N2 2, T4N0 6, and T4N2 1), and 3 with subglottic carcinoma (T3N0 1, and T4N0 2), who underwent partial laryngectomy from 1982 to 1999 were summarized. The choice of surgical procedure was decided on the pathology of the larynx. Epiglottis was used in larynx reconstruction. RESULTS: Out of the 168 cases, 135 cases were decannulated with a decannulation rate of 80.36%, regained deglutation, recovered all laryngeal functions, and resumed normal diet. None presented complication of accidental aspiration. The 3-year and 5-year survival rates were 89.48% and 74.14% respectively. CONCLUSION: Epiglottis has many advantages in laryngeal reconstruction.

Adult↗

PubMed2002

[Relationship between polymorphism of N-acetyltransferase 2 and genetic susceptibility to laryngeal carcinoma].

OBJECTIVE: To investigate the relationship between polymorphism of N-acetyltransferase (NAT2) gene and genetic susceptibility to laryngeal carcinoma. METHODS: A case-control study on 62 laryngeal carcinoma patients and 56 controls was conducted. NAT2 alleles were differentiated by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP) methods using originally created PCR primers and genomic DNA extracted from peripheral white blood cells. Genetic risk for NAT2 genotype was analyzed by smoking index (SI, cigarettes smoked per day x years of smoking). RESULTS: The frequency of NAT2 slow genotype was 80.6% in patients with laryngeal carcinoma and 60.7% in the controls, the difference of which was statistically significant (chi(2) = 5.70, P = 0.017). The odds ratios were 2.70 (95% CI 1.19 approximately 6.11). Among the individuals with NAT2 slow genotype at high level of cigarette smoking, there was a significantly higher risk of 5.64 (95% CI 1.77 approximately 17.92), while those at low level were considered the reference group (OR 1.38, 95% CI 0.42 approximately 4.52). CONCLUSION: NAT2 slow genotype increases the risk of susceptibility to laryngeal carcinoma. The combined effect of NAT2 slow genotype and exposure to smoking is observed during the development of laryngeal cancer.

Aged↗

PubMed2002

[Preservation of laryngeal function in surgery for medial wall pyriform sinus cancer].

OBJECTIVE: To study the feasibility, surgical technique and results of laryngeal function preservation in surgical treatment for medial wall pyriform sinus cancer. METHODS: From 1992 to 1999, 31 patients with medial wall pyriform sinus cancer including stage I 1, II 4, III 14 and IV 12 lesions were treated. Partial resection of pyriform sinus and partial laryngectomy were performed, then, the remains of epiglottis and uni-pedicled sternohyoid myofascial flap were used to restore the defects of larynx. At last, the remaining hypopharyngeal mucosa was sutured to cover the wound of hypopharynx and for artificial rebuild-up. All patients received postoperative radiotherapy. RESULTS: The 3- and 5-year survival rates were 62.1% and 43.6% respectively, with 77.4% patients having laryngeal functions (voice, respiration and deglutition) completely restored and 32.6% partially restored (voice and deglutition). CONCLUSION: Conservative surgery so introduced is feasible for selected medial wall pyriform sinus cancer patients with the lesion completely resected.

Adult↗

PubMed2002

[Surgical management of cervical esophageal carcinoma].

OBJECTIVE: To review the experience of different surgical procedures and corresponding one-stage construction methods for cervical esophageal carcinoma. METHODS: 1. Thirty-three patients with cervical esophageal carcinoma were retrospectively reviewed, including 31 males and 2 females. According to UICC 1997 criteria and pathologic findings showing squamous cell carcinomas, there were 2 patients in T1N0, 4 in T2N0, 1 in T2N1, 6 in T3N0, 6 in T3N1, 7 in T4N0 and 7 in T4N1 categoris. 2. Removal of cervical esophagus was conducted in 13 patients. The type of cervical esophageal reconstruction included direct suturing, pectoralis major musculo-cutaneous flap or combined with the split graft, laryngotracheal flap and colon interposition. Total esophagectomy without thoracotomy was carried out in 20 patients. Reconstruction of the esophagus consisted of 17 stomach pulling-up and 3 colon interposition. Twenty-four patients received radiotherapy postoperatively(dose 50-70 Gy). RESULTS: The resectability of cervical esophageal carcinoma was 100%. The overall follow-up was from 4 months to 10 years. Two and one patient in T1, 2 survived 3 and 5 years, respectively. Three and five-year survival rates for T3, 4 were 7/16 and 3/8, respectively. Twenty-six patients had laryngeal function preserved and acquired good speech. The decannulation rate was 80% (20/25). The incidence of complication was 33.3%, including pharyngeal fistulas in 6 cases, cervical stomal fistulas in 2, cervical stomal stenosis in 2 and splitting of abdominal wall in 2. CONCLUSION: Surgical resection of cervical esophageal carcinoma and resolvation of the extraesophageal invasion is possible. The continuity of the esophagus is restored by pectoralis major muculocutaneous flap, laryngotracheal flap, stomach transposition and colon interposition. Combined with radiotherapy, the resectability and survival rate of the cervical esophageal carcinoma can be improved.

Adult↗