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Biomedical subjects

Q Zheng

Publications and source records attributed to Q Zheng.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Preliminary study of closing cleft of soft palate at an early age for complete cleft palate].

OBJECTIVE: The aim is to introduce the method closing the soft palate at an early age in order to produce better speech and lessen interruption to the development of maxilla. METHODS: Clinical data of 37 cases with treated cleft were preliminarily analyzed. Some dental casts were measured. RESULTS: 1. No complications of anaesthesia and surgery. Except 2 cases whose soft palates were split after surgery were observed as they were coughing. 2. A reduction in the width of the hard palate cleft was noticed. CONCLUSION: Closing the soft palate at an early age is possible and safe. It shows that the Langebeck method could be used to close the hard palate of patients at an early age.

Child, Preschool↗
PubMed2001

Bioactivity of bioresorbable osteosynthetic devices made of hydroxyapatite/poly-DL-lactide composites: an experimental study.

AIM: To investigate the bioactivity of the self-designed biodegradable osteosynthetic devices made of resorbable hydroxyapatite microparticles/poly-DL-lactide (HA/PDLLA) composites. METHOD: Forty-three rabbits with a transverse transcondylar osteotomy of the distal femur were fixed intramedullary by a HA/PDLLA rod, the duration of follow-up were 3, 6, 12, 24 and 36 weeks. Histological, scanning electron microscopic (SEM), energy dispersive X-ray (EDX) and biomechanical analyses were done. RESULTS: Active new bone formation and direct bone-bonding were seen at the bone-implant interface. Generous apatite crystals deposited and grew on the surface of the composites at 3 approximately 6 weeks postoperation. The interfacial shear strength increased significantly. CONCLUSION: Through the incorporating of resorbable HA microparticles, specific bone-bonding and active osteogenic capacity is introduced. This kind of bioactivity, together with other properties such as sufficient mechanical strength, enhanced biocompatibility and radiopacity, which are intrinsically unobtainable in totally resorbable polymer/polymer systems, make the HA/PDLLA composites become a desirable material for the internal fixation of cancellous bone.

Absorbable Implants↗
PubMed2000

Altered patterns of gene expression in response to myocardial infarction.

The use of cDNA microarrays has made it possible to simultaneously analyze gene expression for thousands of genes. Microarray technology was used to evaluate the expression of >4000 genes in a rat model of myocardial infarction. More than 200 genes were identified that showed differential expression in response to myocardial infarction. Gene expression changes were monitored from 2 to 16 weeks after infarction in 2 regions of the heart, the left ventricle free wall and interventricular septum. A novel clustering program was used to identify patterns of expression within this large set of data. Unique patterns were revealed within the transcriptional responses that illuminate changes in biological processes associated with myocardial infarction.

Animals↗
PubMed2000

[Investigation of the effects of biotic field of plant seedling on human body].

In this paper we investigated the effects on human bodies after being placed in the Jiang's guideti cabin with biotic field to receive the plant seedlings' irradiating biological electromagnetic waves. The results found that the erythrocyte membrane permeability and fragidity were decreased, its tenacity increased, the secretion of thyroid and sexual hormones increased, the immune function enhanced and there was no significant alteration of the adrenal cortical hormone secretion. It is suggested that the electromagnetic wave from the plant seedlings is beneficial to the erythrocyte function, improves the metabolism, enhances the adolescent activities, improves sexual activity and enhances immune function, thus it is effective to health care and rejuvenation.

Adult↗
PubMed2000

Clonality analysis of defined cell populations in paraffin-embedded tissue sections by RT-PCR amplification of X-linked G6PD gene.

This paper establishes a method of clonality analysis using the reverse transcription-polymerase chain reaction (RT-PCR) to amplify X-linked G6PD transcripts on defined cell populations microdissected from archival, paraffin-embedded tissue sections. Four known monoclonal low-grade B-cell lymphomas from females who were heterozygous (informative) at the 1131 exonic polymorphic locus of the G6PD gene were used to validate the method. Lymphoma and reactive lesions in each case were separated by microdissection. In order to preserve the intact RNA species in the lesion, sections were digested on the slides before microdissection. A one-step RT-PCR was performed with a single pair of primers, one of which contained a mismatched base adjacent to the polymorphic site, to generate a PvuI cutting site. Successful amplification and allele identification by PvuI digestion were achieved from all RNA samples studied. Three of four samples from non-neoplastic reactive lesions showed two bands with equal intensity, representing transcription of the two alleles of the G6PD gene, while the corresponding tumour samples demonstrated a biased intensity in one allele, indicating monoclonality. To assess the method further, the clonal nature of in situ and invasive breast cancers was examined, along with adjacent normal breast tissue and hyperplastic lesions from three informative females from our archives. Apart from the clusters of normal terminal duct-lobular units, all lesions were monoclonal. This result is in agreement with data derived from other X-linked gene studies and loss of heterozygosity (LOH) analyses of pre-invasive breast disease. The results suggest that the clonality analysis method presented here is simple and reliable, and is therefore potentially applicable in a wide range of pathological conditions.

Breast↗
PubMed2000

Isolated pelvic hyperthermochemotherapeutic perfusion--an experimental study on isolating efficacy.

Hyperthermochemotherapeutic perfusion model through isolated pelvic vessels was developed to evaluate the leakage of hyperthermia and drugs (such as adriamycin) from the isolated pelvic circulation to systemic circulation and its associated side/toxic effects. The isolated pelvic circulation was perfused through a femoral artery catheter with hyperthermic (48 degrees C to 55 degrees C) adriamycin solution (50 micrograms/ml) for 30 min. The efflux was drained through a femoral vein catheter. And the pelvic temperature was kept at the level of 43 +/- 0.5 degrees C. The temperature of pelvic circulation was kept at 4 degrees C to 5 degrees C greater than the systemic/core temperature. The adriamycin concentration of pelvic efflux was 12 to 46 folds of that of systemic serum. The difference between them was very significant (P < 0.001). As the perfusion pressure was increased, which kept lower than the mean systemic artery pressure, the leakage of the adriamycin from the isolated pelvic circulation to systemic circulation was increased, but there was no significant difference between them (P > 0.05). During isolated perfusion, the systemic blood dynamics remained stable and there were no organic injuries on the important organs. It was suggested that the isolating efficacy of the modality of isolated pelvic hyperthermochemotherapeutic perfusion through vessels was rather high. The hyperthermia and drugs could be effectively limited in the isolated pelvic region with minor side effects on the systemic circulation and important organs.

Animals↗
PubMed2000

Cloning and expression of rat transforming growth factor beta 1 cDNA in osteoblasts.

Rat transforming growth factor beta 1 (rTGF beta 1) cDNA from rat lymphocytes was cloned by RT-PCR and inserted into pcDNA3 to construct an eukaryotic expression vector, which was named pcDNA3-TGF beta 1. The cloned gene was confirmed to code rat TGF beta 1 by restriction enzyme analysis. pcDNA3-TGF beta 1 plasmid was transfected into rat osteoblasts by using liposome-mediated gene transfer technique and the expression of TGF beta 1 was detected by using immunohistochemical staining assay. It was found that the rat TGF beta 1 expression product was obviously detectable in the transfected osteoblasts in 48 h. High expression of TGF beta 1 was obtained in the rat osteoblasts in which the constructed TGF beta 1 expression vector was transfected.

Animals↗
PubMed2000

A retrospective analysis of the gluteal muscles contracture and discussion of the relative problems.

The operation methods, clinical classification, postoperative function exercise of gluteal muscles contracture were investigated. Clinically and retrospectively, treatment of 1280 patients with gluteal muscles contracture, being subjected to a "Z-shaped" release lengthening operation and efficiency exercise, was clearly standardized. All the cases were followed up from 3 months to 2 years with the effective rate being 100%, the cure rate being 98.5%, the recent complications being 5%, and the far complications being 0.2%. It was concluded that the clear diagnosis combined with standarized operation and efficiency functional exercise could greatly improve the therapeutic effects of gluteal muscles contracture.

Adolescent↗
PubMed2000

Effect of absorbable hydroxyapatite/poly-DL-lactide rods on experimental fracture healing.

In order to investigate the effect of a new institute-designed absorbable hydroxyapatite microparticles/poly-DL-lactide (HA/PDLLA) fracture fixation devices on experimental fracture healing, 25 rabbits with a transverse transcondylar osteotomy of the distal femur were fixed intramedullary by a HA/PDLLA rod (4.5 mm in diameter, 30-40 mm in length). The follow-up time lasted 1, 2, 4, 6 and 12 week(s). Roentgenographic, histological and ultrastructural analyses were conducted. The results showed that all osteotomies united within 6 weeks without delay. No accumulation of inflammatory cells was seen. Ultrastructural studies showed that polymorphonuclear neutrophils and macrophages were observed mainly at the 1st week, but only few were noted at the 2nd week. The inflammatory and debridement stages were not prolonged. Large amount of active fibroblasts and some chondroblasts were observed at the 2nd week, suggesting a fibrous callus stage. The main cellularity at 4th week was osteoblasts and osteocytes. Part of osteocytes had already entered the static stage at the 6th week. Our experiment showed that the HA/PDLLA had good biocompatibility, sufficient mechanical strength and caused no delay to the fracture healing.

Animals↗
PubMed2000

Invasion and metastasis of hepatocellular carcinoma in relation to urokinase-type plasminogen activator, its receptor and inhibitor.

This study was designed to investigate the relationship of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor type-1 (PAI-1) to invasion and metastasis of hepatocellular carcinoma (HCC). The expression of uPA, uPAR, and PAI-1 in HCC was determined by immunohistochemistry, Northern blot, and an LCI-D20 nude mouse metastatic model of HCC. The overexpression of uPA, uPAR, and PAI-1 was found in HCC, especially in the patients with portal cancer embolus, tumor invasion, and metastasis. Immunohistochemistry results showed that the rate of positive staining of uPA, uPAR, and PAI-1 were higher in HCC than those in the control groups consisting of cancer-adjacent tissue and normal liver tissue. In the case of HCC invasion, positive uPA and uPAR were seen in 16 and 19 out of 22 patients, respectively (P<0.01 and P<0.001, respectively, as compared with the patients without invasion). In those with portal cancer embolus and tumor metastasis, positive uPAR was eight out of eight and six out of six patients. In those with tumor recurrence, positive uPAR was 15 out of 17 patients (P<0.01 vs. no recurrence). In patients who died within 2 years after surgery, positive uPAR was 12 out of 12 patients (P<0.01 vs. survival), and positive PAI-1 was nine out of 12 patients (P<0.05 vs. survival). In those in which uPA, uPAR, and PAI-1 were all positive staining, stronger cancer invasiveness and higher mortality were found (P<0.05 vs. patients with all negative staining). In 30 patients tested with Northern blot analysis, the results were similar to those tested with immunohistochemistry. Higher expression of uPA mRNA and PAI-1 mRNA were detected in tumor tissues and embolus. In the patients with positive signals of uPA mRNA and PAI-1 mRNA, invasive cases were found in seven out of 19 and eight out of 18 patients, respectively, which were significantly higher than those showing negative signals (P<0.05). In the LCI-D20 nude mouse metastatic model of HCC (MMHCC), PAI-1 activity in plasma and tumor tissue increased with tumor growth, invasion, and metastasis. At an advanced stage of MMHCC, PAI-1 activity rose to 15.4+/-0.7 Au/ml in plasma and 0.8+/-0.3 Au/mg in tumor extracts, which was significantly higher than 6.2+/-1.8 Au/ml in plasma and 0.4+/-0.1 Au/mg in extracts at an early stage (P<0.05). PAI-1 activity related to the changes of serum AFP and tumor progress were r = 0.9544 and r = 0.9648, respectively (P<0.05). The data suggest that the expression of uPA, uPAR, and PAI-1 is increased in HCC, and related to the invasiveness, metastasis, and prognosis of HCC.

Animals↗
PubMed2000

Structure characterization of human RalGDS gene, and the identification of its novel variant.

RalGDS is a guanine nucleotide dissociation stimulator for Ral, which is a member of the Ras GTPase superfamily that regulates cellular proliferation, differentiation and transformation by mediating multiple signal transduction pathways. RalGDS can specifically promote the conversion from an inactive GDP-bound state to an active GTP-bound state for Ral. The cDNA of human RalGDS has been cloned recently. In this paper, by comparison between the gene's genomic and cDNA seqence, we determined the structure of the gene, which showed that the reported human RalGDS transcribed from 18 exons. Furthermore, a novel variant of RalGDS that codes for a protein with a different N-terminus was cloned and identified. Northern hybridization revealed that the novel transcript was of 6.0 kb in length while the transcript previously reported is of 4.0 kb. Both transcripts were ubiquitously expressed in human adult tissues examined, albeit with different amounts. In addition, this novel transcript was proved to be caused by employment of a new exon, designated as exon 1a, instead of the one, designated as exon 1b, in the reported cDNA. Thus, the RalGDS gene consists of at least 19 exons and spanned a 44 kb region. The length between exon 1a and exon 2 was 33 kb, while the length between exon 1b and exon 2 was 8.8 kb.

Amino Acid Sequence↗
PubMed2000

Direct analysis and identification of triterpene glycosides by LC/MS in black cohosh, Cimicifuga racemosa, and in several commercially available black cohosh products.

A method to directly identify triterpene glycosides using reversed-phase liquid chromatography with positive atmospheric pressure chemical ionization mass spectrometry (LC/(+)APCIMS) was developed. Based on the analysis of the molecular weight, fragment ions, selected ion chromatograms, a number of triterpene glycosides, including actein, 27-deoxyactein, cimicfugoside M, and cimicifugoside, from Cimicifuga racemosa were studied. A chromone, cimifugin, from C. foetida was also identified. Cimicifugoside M and cimifugin can specifically serve as indicators for species identification. The method can, therefore, be used to distinguish black cohosh products from among different plant species for quality control purposes.

Chromatography, Liquid↗
PubMed2000

Comparative cholinergic neurotoxicity of oral chlorpyrifos exposures in preweanling and adult rats.

Chlorpyrifos (CPF) is a common organophosphorus (OP) pesticide. Previous studies have demonstrated that neonatal rats are more sensitive than adults to the acute toxicity of high dosages of CPF. The present study examined lethality and age-related differences in neurochemical indicators and functional signs of neurotoxicity following a broad range of acute and repeated oral CPF exposures. There was about a 9-fold difference in sensitivity to the acute-dose lethality of chlorpyrifos among neonatal (7 days-of-age) and adult (90 days-of-age) rats (LD(10): neonates = 15 mg/kg; adults = 136 mg/kg), while juvenile rats (21 days-of-age) exhibited intermediate sensitivity (LD(10) = 47 mg/kg). Neonatal and adult rats (n = 5-7/treatment/age group/time point) were given CPF (0, 0.15, 0.45, 0. 75, 1.5, 4.5, 7.5, or 15 mg/kg/day) for 14 days and sacrificed 4 h after either the first or 14th dose for neurochemical measurements (cholinesterase activity in frontal cortex, plasma and RBC, and muscarinic ([(3)H]QNB) and nicotinic ([(3)H]epibatidine) receptor binding in frontal cortex. No overt signs of functional toxicity (involuntary movements, SLUD signs) were noted in either age group by 4 h after the first dose. With repeated CPF exposures, however, signs of cholinergic toxicity were noted in both age groups at the higher dose levels [no observed effect levels (NOELs): neonate = 4.5 mg/kg/day; adult = 7.5 mg/kg/day]. Similar degrees of ChE inhibition were noted in neonatal brain and blood fractions following acute exposure, but substantial ChE inhibition was only noted in adult plasma and RBC 4 h after the first treatment. Following repeated CPF exposures, similar degrees of ChE inhibition were again noted in tissues from immature animals, but a wide range of sensitivity to inhibition was noted in adult tissues. NOELs based on ChE inhibition for adults were about 1->/=10-fold higher than in neonates with acute exposure but only 0.2-2 times higher with repeated dosing. Moreover, dose-related inhibition of brain ChE was similar between age groups, and similar reductions in both QNB and epibatidine binding were noted between the age groups after repeated dosing, even though by the end of the dosing period young animals (juveniles) were still about 3 times more sensitive than adults, based on acute lethality. We conclude that while immature animals can be markedly more sensitive to lethal effects of high doses of CPF, lesser or no age-related differences are apparent, based on non-lethal endpoints, in particular with repeated exposures.

Aging↗
PubMed2000

Modeling and predicting selected immunological effects of a chemical stressor (3,4-dichloropropionanilide) using the area under the corticosterone concentration versus time curve.

Many chemicals and drugs can induce a neuroendocrine stress response that can be immunosuppressive. Mathematical models have been developed that allow prediction of the immunological impact of such stress responses in mice on the basis of exposure to the important stress-related mediator corticosterone. The area under the corticosterone concentration vs. time curve (AUC) has been used as an indicator of cumulative corticosterone exposure in these modeling studies. In the present study, an immunotoxicant known to induce a stress response, 3,4-dichloropropionanilide (propanil), was evaluated to determine if corticosterone AUC values are related to suppression of immunological parameters in mice treated with this chemical. Linear relationships between corticosterone AUC values and suppression of the following parameters were noted in B6C3F1 female mice: thymus cellularity and thymus subpopulation percentages, splenic subpopulation percentages, natural killer cell activity, MHC class II protein expression, and IgG1 and IgG2a antibody responses to antigen. Linear models derived in previous studies using mice treated with exogenous corticosterone or with restraint stress effectively predicted the immunological effects of 3, 4-dichloropropionanilide on the basis of corticosterone AUC values. The models derived using immobilization stress were more effective (r(2) for observed vs. predicted = 0.90) than the models derived using mice treated with exogenous corticosterone (r(2) for observed vs. predicted = 0.65). This was expected, because most stressors induce a variety of immunomodulatory mediators, not just corticosterone. These findings have implications for risk assessment in immunotoxicology.

Animals↗
PubMed2000

Comparison of reg I and reg III levels during acute pancreatitis in the rat.

OBJECTIVE: To study alterations of serum levels of the pancreatic reg family of proteins in two models of acute pancreatitis. SUMMARY BACKGROUND DATA: The pancreatic reg family of proteins is expressed in the acinar pancreas. Reg I (pancreatic stone protein, PSP) and reg III (pancreatitis-associated protein, PAP) are induced after the onset of acute pancreatitis, and both have been proposed as potential markers of pancreatitis. METHODS: Pancreatitis was induced in rats by either retrograde infusion of sodium taurocholate or by direct trauma. Serum samples were obtained daily for 4 days after the procedure, and the animals were then killed. Twelve animals underwent sham procedure and six underwent daily analysis without surgery. Levels of reg I/PSP and reg III/PAP were estimated by enzyme-linked immunosorbent assay. RESULTS: Reg III/PAP levels increased significantly the first day after induction of both types of pancreatitis and rapidly returned to baseline in all survivors. Even animals who received retrograde infusion of saline showed a mild increase in reg III/PAP on the first day, whereas control animals that did not undergo surgery showed no variations. Reg I/PSP serum levels remained unchanged throughout all experimental periods. Postinjury reg III/PAP levels significantly correlated with severity of the pancreatic injury and animal survival; reg I/PSP levels did not. CONCLUSION: After induction of pancreatitis, serum levels of reg I and III protein differ significantly. Reg III/PAP levels are a sensitive marker of pancreatic injury and early in the disease may be a useful prognostic indicator for disease severity.

Acute Disease↗
PubMed2000

New immunofluorescence assays for detection of Human herpesvirus 8-specific antibodies.

Several assays have been developed for detection of immunoglobulin G antibodies to Human herpesvirus 8 (HHV-8), including immunofluorescence assays (IFAs) and enzyme-linked immunosorbent assays (ELISAs). However, the specificity and sensitivity of these assays are not completely defined due to the lack of a "gold standard." Although IFAs based on primary effusion lymphoma (PEL) cell lines are used widely, the assays can be confounded by nonspecific reactions against cellular components and potential cross-reaction with antibodies against other herpesviruses. To provide more reliable IFAs, we established recombinant Semliki Forest viruses (rSFVs) expressing the HHV-8-specific proteins ORF73 and K8.1 and used BHK-21 cells infected with these rSFVs for IFA (ORF73-IFA and K8.1-IFA). Expression of the HHV-8-specific proteins at very high levels by the rSFV system allowed easy scoring for IFA and thereby increased specificity. The rSFV system also allowed detection of antibodies against glycosylation-dependent epitopes of K8.1. Titers measured by rSFV-based IFAs and PEL-based IFAs correlated well (correlation coefficients of >0.9), and concordances of seroreactivities between rSFV-based and PEL-based IFAs were >97% (kappa > 0.93). K8.1-IFA was more sensitive than either ORF73-IFA or peptide ELISAs. Using PEL-based lytic IFA as a reference assay, the sensitivity and specificity of K8.1-IFA were estimated to be 94 and 100%, respectively. HHV-8 prevalences determined by K8.1-IFA among the human immunodeficiency virus (HIV)-positive (HIV(+)) Kaposi's sarcoma (KS) patients, HIV(+) KS(-) patients, and healthy controls were 100, 65, and 6.7%, respectively, which were consistent with prior reports. Therefore, our rSFV-based IFAs may provide a specific and sensitive method for use in epidemiology studies. In addition, they will provide a basis for further development of diagnostic tests for HHV-8 infection.

Animals↗
PubMed2000

[Refined chromosome assignment of human novel H-RalGDS gene on chromosome 9q34.1 by using radiation hybrid genebridge 4 panel].

OBJECTIVE: Refined chromosome assignment of a novel Ras-related H-RalGDS gene (the human homology of rat RalGDS, Ral guanine nucleotide dissociation stimulator recently cloned and characterized by our laboratory) by using human/rodent radiation somatic cell hybrid panel GB4. METHODS: According to the sequence of the 3'-untranslated region of H-RalGDS cDNA, forward and reverse primers were designed and used to amplify the human/rodent somatic radiation hybrid Genebridge 4 panel. The PCR result of each cell line of the panel was scored in a certain way and put into the related internet site of WI/MIT Radiation Hybrid Mapper for RH mapping and comprehensive analysis. RESULTS: The H-RalGDS gene was successfully localized to the framework of chromosome 9. After referring to literature and further integrated mapping analysis of the physical, genetic linkage and cytological mappings, the gene was assigned precisely between the markers SURF5 and RPL7A which had already been assigned to human chromosome 9q34.1. CONCLUSION: The localization of H-RalGDS not only contributed much to the construction of refined gene map and cytogenetic map within the region of chromosome 9q34, but also made clear that RH mapping of human novel genes is a simple, convenient and reliable method which can provide even more genetic information of genes within chromosomal regions.

Animals↗