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Biomedical subjects

C Zheng

Publications and source records attributed to C Zheng.

At least 73 records · Page 4Linked to original sources
PubMed2000

Adenovirus-mediated p16INK4 gene transfer significantly suppresses human breast cancer growth.

The p16INK4 tumor suppressor gene encodes a protein that inhibits cyclin-dependent kinase 4, and its homologous deletion is common in human breast cancer. p16INK4 gene transfer has been reported to be efficacious in inducing growth inhibition of various human tumors such as brain, lung, prostate, and esophageal cancers. However, the efficiency of the p16INK4 gene with regard to growth inhibition of human breast cancer has not been studied extensively. To examine its tumor-suppressive function and its potential in breast cancer gene therapy, the wild-type p16INK4 gene was expressed in an adenovirus-mediated gene delivery system and introduced into breast cancer cell lines that do not express p16INK4 protein. Expression of the introduced p16INK4 blocked tumor cell entry into the S phase of the cell cycle, induced tumor cell apoptosis, and inhibited tumor cell proliferation both in vitro and in vivo. These results strongly suggest that p16INK4 is a tumor suppressor gene and suggest that it has potential utility in breast cancer gene therapy.

Adenoviridae↗
PubMed2000

Interleukin 6, tumour necrosis factor alpha, interleukin 1beta and interleukin 1 receptor antagonist promoter or coding gene polymorphisms in multiple myeloma.

Proinflammatory cytokines such as interleukin 6 (IL-6), tumour necrosis factor alpha (TNF-alpha) and IL-1beta are considered to be involved in the pathogenesis of multiple myeloma (MM). In the present study, we examined a G/C polymorphism at position -174 in the promoter region of IL-6, a biallelic polymorphism at position -308 in the promoter region of TNF-alpha, the TaqI restriction fragment length polymorphism in exon 5 of IL-1beta and a variable number of identical tandem repeat polymorphisms in intron 2 of IL-1 receptor antagonist (IL-1Ra) genes. The alleles of these loci are known to influence the level of production of the cytokines and the IL-1Ra. Seventy-three patients with MM, 27 with monoclonal gammopathy of undetermined significance (MGUS) and 129 healthy individuals were included. No difference was found between patients and healthy controls or between MM and MGUS patients in the distributions of genotypes and frequencies of alleles of the IL-6 (-174), TNF-alpha (-308), IL-1beta TaqI and IL-1Ra gene polymorphisms. No associations between the polymorphisms at the loci under study and clinical factors such as age, sex, clinical stage at onset and M-protein type were observed. Our results indicate that the cytokine (IL-6, TNF-alpha and IL-1beta) and IL-Ra gene polymorphisms do not confer susceptibility to the development of MM.

Adult↗
PubMed2000

Effect of intranasal treatment with capsaicin on the recurrence of polyps after polypectomy and ethmoidectomy.

The aim of this study was to evaluate the influence of five intranasal applications of capsaicin, performed after endoscopic polypectomy associated with partial middle turbinectomy and anterior ethmoidectomy, on the recurrence of nasal polyps and the intensity of nasal obstruction and rhinorrhea. Fifty-one patients (19 females, 32 males, mean age 43 years) suffering from nasal polyposis for more than 1 year were included in this double blind, randomized, placebo-controlled study. During post-surgical controls, local anaesthesia and vasoconstriction of the middle meatus area were performed in all patients with a cotton pellet soaked with lidocain and adrenaline. In 29 patients, the same type of cotton pellet soaked with capsaicin (3 x 10(-6) mol. dissolved in 70% ethanol) was left into the middle meatus of both nostrils for 20 min. As a control group, 22 patients, matched for age and sex, were treated with the capsaicin vehicle alone (70% ethanol). All patients studied received the intranasal treatment once a week for 5 weeks. Subjective evaluations of nasal airway resistance (NAR) and rhinorrhea were recorded by means of a visual analogue scale. Clinical staging of the nasal polyposis (graded from stage 0 = absence of polyp to stage 3 = polyps occupying the entire nasal cavity) was evaluated by the same ENT specialist (ZW) using a 0 degrees endoscope. All parameters were recorded for each patient 1 week before surgery, then once a month for 9 months. Patients treated by endoscopic surgery followed by intranasal capsaicin application, reported a marked reduction in their NAR compared with the pretreatment evaluation (p<0.001). In contrast, patients treated with the vehicle alone did not have any significant improvement of their subjective NAR. Subjective rhinorrhea was not modified by either treatment. Patients treated with capsaicin showed a significant smaller staging of their nasal polyposis compared with the control group (p<0.001). These observations suggest that endoscopic surgery followed by intranasal capsaicin application reduces polyps and nasal obstruction recurrence and could be an alternative treatment to expensive corticosteroids in developing countries.

Administration, Intranasal↗
PubMed2000

Pyk2 and FAK differentially regulate progression of the cell cycle.

We have previously identified FAK and its associated signaling pathways as a mediator of cell cycle progression by integrins. In this report, we have analyzed the potential role and mechanism of Pyk2, a tyrosine kinase closely related to FAK, in cell cycle regulation by using tetracycline-regulated expression system as well as chimeric molecules. We have found that induction of Pyk2 inhibited G(1) to S phase transition whereas comparable induction of FAK expression accelerated it. Furthermore, expression of a chimeric protein containing Pyk2 N-terminal and kinase domain and FAK C-terminal domain (PFhy1) increased cell cycle progression as FAK. Conversely, the complementary chimeric molecule containing FAK N-terminal and kinase domain and Pyk2 C-terminal domain (FPhy2) inhibited cell cycle progression to an even greater extent than Pyk2. Biochemical analyses indicated that Pyk2 and FPhy2 stimulated JNK activation whereas FAK or PFhy1 had little effect on it, suggesting that differential activation of JNK by Pyk2 may contribute to its inhibition of cell cycle progression. In addition, Pyk2 and FPhy2 to a greater extent also inhibited Erk activation in cell adhesion whereas FAK and PFhy1 stimulated it, suggesting a role for Erk activation in mediating differential regulation of cell cycle by Pyk2 and FAK. A role for Erk and JNK pathways in mediating the cell cycle regulation by FAK and Pyk2 was also confirmed by using chemical inhibitors for these pathways. Finally, we showed that while FAK and PFhy1 were present in focal contacts, Pyk2 and FPhy2 were localized in the cytoplasm. Interestingly, both Pyk2 and FPhy2 (to a greater extent) were tyrosine phosphorylated and associated with Src and Fyn. This suggested that they may inhibit Erk activation in an analogous manner as the mislocalized FAK mutant (&Dgr;)C14 described previously by competing with endogenous FAK for binding signaling molecules such as Src and Fyn. This model is further supported by an inhibition of endogenous FAK association with active Src by Pyk2 and FPhy2 and a partial rescue by FAK of Pyk2-mediated cell cycle inhibition.

Animals↗
PubMed2000

Closed-loop identification of carotid sinus baroreflex transfer characteristics using electrical stimulation.

Although random aortic pressure (AOP) perturbation according to a binary white noise sequence enables us to estimate open-loop dynamic characteristics of the carotid sinus baroreflex under closed-loop conditions, the necessity of arterial catheter implantation limits the applicability of this method in freely moving animal experiments. Thus, we explored a closed-loop system identification method using electrical stimulation. In 6 anesthetized and vagotomized rabbits, we stimulated the aortic depressor nerve with a binary white noise sequence (0-10 Hz) under baroreflex closed-loop conditions while measuring cardiac sympathetic nerve activity (SNA) and AOP. We used a closed-loop identification method to estimate the peripheral arc transfer function from SNA to AOP. The peripheral arc transfer function approximated a second-order low-pass filter and its fitted parameters did not differ from those obtained by an open-loop identification method (dynamic gain: 1.16+/-0.32 vs. 1.02+/-0.11; natural frequency: 0.08+/-0.03 vs. 0.09+/-0.03 Hz; damping ratio: 1.53+/-0.15 vs. 1.57+/-0.21). In 6 different rabbits, we applied intermittent rapid pacing (396 beats/min) under baroreflex closed-loop conditions to estimate the neural arc transfer function from AOP to SNA. The neural arc transfer function approximated a first-order high-pass filter and its fitted parameters did not differ from those obtained by an open-loop identification method (dynamic gain: -1.15+/-0.45 vs. -1.06+/-0.05; corner frequency: 0.12+/-0.05 vs. 0.13+/-0.03 Hz). In conclusion, the closed-loop identification method using electrical stimulation is effective to estimate the neural and peripheral arc transfer functions.

Animals↗
PubMed2000

[Studies on properties of biofriction and wear for friction pairs of UHMWPE and Ti matrix-TiN-TiC gradient film materials].

In order to search the possible application of friction pairs of UHMWPE and Ti6Al4V-TiN-TiC etc. gradient materials to total hip joint replacements, we have prepared Ti6Al4V-TiN-TiC etc. gradient film materials by using N ion implant, d. c plasma CVD(PCVD). The properties of biological friction and wear for friction pairs of HUMWPE and Ti6Al4V-TiN-TiC etc. gradient film materials were investigated. The friction coefficient of friction paris and the wear loss of worn UHMWPE were measured; the surface morphology was observed by SEM. It has been shown that in human serum lubrication the wear loss of HUMWPE decreases with the increase in the surface hardness of its pairing ceramic film material. The pairing Ti6Al4V-TiN-TiC gradient film material possesses highest surface hardness, compared with other materials studied; UHMWPE wear loss in lowest. The wear mechanism of studied pairs has been analysed as well in the present paper.

Biocompatible Materials↗
PubMed2000

[3-D direct matching interpolation for rotary scanning echo-cardial images].

In the present paper, a method of three dimension direct matching interpolation for a series of 2-D echo-cardial images with intersecting each other and arranging at an angle in space has been developed. It is different from the conventional interpolation. During the interpolation, sectional images are acquired and the 3-D spatial position of "empty voxel" in sectional images is located; secondly, the cubic volume is constructed, and the motion orbit of images between two windows where the nearest original image intersects to the volume is found up, passing through the "empty voxel"; In the end, based on the matching pixels, the "empty voxel" is interpolated. This method simplifies the two interopolating procedures of the conventional methods into one procedure, and overcomes the shortcoming of the overlap of image data. Experiments show that the accuracy and reasonability of interpolation can be improved by the proposed method.

Echocardiography↗
PubMed2000

[High resolution time-frequency analysis method for extracting the sleep spindles].

In this paper, a new method for the auto-detection sleep spindle is presented. The method is based on the Discrete Gabor Spectrogram (DGS), a high resolution time-frequency analysis. Sleep EEG5 were processed and the spindles were accurately detected. By, this method the accuracy of auto-detection almost approched the level of visulal detection. Auto-detection of sleep spindles could release the expert from reading long term sleep EEG and provide useful information for sleep studies.

Adult↗
PubMed2000

[The development of an extracting method for high frequency components of abnormal intra-QRS of exercise ECG signal].

This article introduces a method of extracting high frequency components of abnormal intra-QRS of exercise ECG signal by using spline function interpolation algorithm, and defines QRSe of the residual signal as quantitative index. Some expected results have been obtained. This method is an effective measuring approach to further researches on the high frequency components of exercise and other ECG signals.

Electrocardiography↗
PubMed2000

Salivary glands as a model for craniofacial applications of gene transfer.

The potential applications of gene transfer technology to all branches of medicine are increasing. It is quite likely that within the next 10-20 years surgical practice routinely will utilize gene transfer, at least adjunctively. The purpose of this review is to familiarize the oral and maxillofacial surgeon with this technology. Studies performed with salivary glands in animal models are presented as examples of proof of concept.

Animals↗
PubMed2000

[The construction of PQE-ARL-1 recombinant expression plasmid and the preparation and purification of ARL-1 protein].

OBJECTIVE: To further understand the function and biological activity of aldose reductase like-1 (ARL-1), and to provide the basis for the preparation of the specific antibody against ARL-1. METHODS: The ARL-1 cDNA was cloned into procaryotic expression vector PQE-30 and the recombinant ARL-1 expressed in E.coli M(15); then Ni(+)-NTA agarose columns were used to purify the ARL-1 protein. RESULTS: With the digestion of the enzymes, we identified that the ARL-1 gene was inserted into the procaryotic expression vector PQE-30. The expression products of PQE-ARL-1 (human recombinant ARL-1) showed a single protein band on SDS-PAGE. The molecular weight of ARL-1 was approximately 37.7 x 10(3) and the expression level was about 25% of the total bacterial protein. The concentration of ARL-1 protein was about 100mg/L. CONCLUSION: The construction of the recombinant plasmid PQE-ARL-1 and the preparation of the protein ARL-1 have laid a solid foundation for further studying the function of ARL-1 and preparing the specific antibody against ARL-1.

Aldehyde Reductase↗
PubMed2000

[Study on statistical method of distribution for erythrocyte morphological features by computerized image processing].

This study sought to develop a new statistic method for the semiautomatic analysis and classification of erythrocyte morphology based on the morphological features and shape analysis of erythrocytes by computer image processing. Shape factor as the description of the erythrocyte morphological features was used for the shape classification of erythrocytes. And the models and algorithms of erythrocytes image segmentation, cell body shape recognition and measure can be implemented through the VC++. The present method can efficiently and semi-automatically provide the statistical analysis of erythrocyte morphology, and can give the distribution of erythrocyte morphological features. The result showed that there was a significant difference between the distribution curves of the normal erythrocyte morphology (one apex) and hemolytic anemia's (two apices). By this way, it can be obtained the proportion data of different cell bodies' shapes. This method could provide some information for the study and diagnosis of the diseases (e.g. hemolytic anemia, pre-leukemia) related to erythrocyte morphology.

Algorithms↗
PubMed2000

[Study on human sensitivity of extremely low frequency electromagnetic field].

In this paper, the action potential through membrane is calculated and analyzed based on the crowd model. The analysis shows that membrane action potential will be amplified if the coefficient k1, k2 meet some certain conditions. This effect could cause ionic current increase and even results in electroporation, membrane broken. The result can be used to explain some athermal bioeffect of living beings in weak EMF and is helpful for biomedicine application.

Cell Membrane↗
PubMed2000

[The imbalance of Th1/Th2 cytokine expression in peripheral blood mononuclear cell from asthmatic patients and the effect of erythromycin on these cytokines].

OBJECTIVE: To observe the state of Th1/Th2 cytokine expression in peripheral blood mononuclear cells (PBMCs) from asthmatic patients and the effect of erythromycin (Ery) on it. METHODS: 23 asthmatic patients and 10 healthy volunteers were included. The mRNA expression for Th1/Th2 cytokines in PBMC before and after the culture with Ery were detected by RT-PCR, considering IL-2 and IFN-gamma as Th1 cytokines, and IL-4, IL-6, IL-10 as Th2 ones. RESULTS: The positive rate of mRNA expression for Th2-derived IL-4, IL-6, IL-10 in the study group were 18/23, 19/23 and 10/23 respectively, and those for IFN-gamma and IL-2 produced by Th1 cells were 1/23 and 13/23, respectively. In the control group, the positive rate for IL-4, IL-6, IL-10 were 0/10, 2/10 and 1/10, respectively, and those for IL-2 and IFN-gamma were both 1/10. Comparing with the control group, the positive rate of mRNA expression for IL-4 and IL-6 in PBMC from asthmatic patients were significantly higher (P = 0.00003, 0.001 respectively). After the culture with Ery for 48 h, the positive rate for IL-4 expression in the study group decreased from 18/23 to 5/23 (P = 0.0006), and IL-6 from 19/23 to 9/23 (P = 0.006). The positive rate for IFN-gamma expression was elevated while IL-2 decreased(But both had no statistical significance). There was no difference observed before and after the culture with Ery in the control group. CONCLUSIONS: There is a predominant expression of Th2-type cytokines in PBMC from asthmatic patients. Ery can down-regulate the mRNA expression for IL-4 and IL-6 in asthmatic patients, and might convert the imbalance of Th1/Th2 cytokine expression in asthmatic patients.

Adult↗
PubMed2000

[Hemorrhagic shock increases the occurrence of bacterial translocation].

OBJECTIVE: To determine whether hemorrhagic shock (HS) increases the occurrence of bacterial translocation (BT). METHODS: 100 patients were divided into 4 groups: control group (group I, 34 patients); group with hemorrhagic shock (HS) caused by closed blunt abdominal trauma (group II, 23); group caused by closed blunt abdominal trauma without HS (group III 15); and group with HS caused by intra-abdominal viscus hemorrhage (group IV 28). Preoperative and postoperative samples were taken from peripheral blood, visceral peritoneal swab, portal vein blood, ileal mesenteric lymph node, liver and spleen biopsy respectively for aerobic and anaerobic culture. RESULTS: The positive culture rates of these groups were 6%, 65%, 13%, 68% respectively. The difference between the control and experimental groups was significant(P < 0.05). The difference was also significant between group I and II and between I and IV (P < 0.01), whereas it was not significant between I and III, and between II and IV (P > 0.05). CONCLUSION: HS increases the occurrence of BT.

Abdominal Injuries↗
PubMed2000

[Postoperative recurrence of T2 stage gastric cancer].

OBJECTIVE: To study the clinicopathological characteristics of T(2) gastric cancer and its postoperative recurrence. METHOD: 124 T(2) gastric cancer patients were divided into two groups: 42 patients with postoperative recurrence (Group 1) and 82 patients without recurrence (Group 2). RESULTS: The recurrence rate of local tumor was significantly lower in Group 1 (26.2%) than in Group 2 (45.1%). Deep invasion was highly different between the two groups. Circular muscle tumors were seen in Group 1 (4.8%) and in Group 2 (30.5%), whereas sub-serosa tumors were seen in Group 1 (61.8%) and in Group 2 (25.6%). The rate of lymph node metastasis was significantly higher in Group 1 (88.1%) than in Group 2 (57.3%). The mean number of positive nodes was (7.02 +/- 6.50) in Group 1 and (2.16 +/- 2.04) in Group 2(P < 0.01). Local recurrence rate and distant metastasis rate in Group 1 were 54.8% and 46.2% respectively. The median survival was 26.5 months in Group 1 and 57.0 months in Group 2 (P < 0.01). The 1-, 3-, 5-year survival rate in Group 1 and Group 2 were 61.4% vs 97.6%, 18.7% vs 95.9%, and 8.3% vs 95.9%, respectively. CONCLUSION: Poor prognosis is seen in T(2) gastric cancer patients with postoperative recurrence. Extended gastrectomy and multi-therapy are necessary for the patients with the risk factors so as to decrease local recurrence.

Adult↗
PubMed2000

[Laparoscopic gastric resection].

OBJECTIVE: To modify laparoscopic surgery for gastric diseases. METHODS: From December 1992 to January 1999, 61 gastric laparoscopic operations were performed in our hospital. The age of the patients ranged from 29 to 78 years (mean 57.4). 17 patients had Billroth II gastrectomy, 1 Billroth I gastrectomy, 2 proximal subtotal gastrectomy, 5 highly selective vagotomy, 3 gastrostomy, and 33 resection of gastric submucosal benign tumor. 54 patients (88.5%) underwent complete laparoscopy, and 7 (11.5%) an assisted one RESULTS: The mean operative time was (164.2 +/- 93.5) min, the mean estimated blood loss was (218.3 +/- 166.6) ml, and the mean hospital stay was (6.8 +/- 2.1) days. Flatus was present within 48 hours in 86% of the patients. Two patients had laparoscopic surgery for early gastric cancer, and were followed up for more than 55 months. Postoperative complication were noted in 2 patients, who were cured by reoperation and endoscopy therapy respectively. Only 4 patients required postoperative analgesics. CONCLUSION: Although specific indications need to be defined, laparoscopic surgery is feasible. But long-term follow-up should be made to evaluate its efficacy in treatment of gastric cancer.

Adult↗