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Biomedical subjects

Z Shen

Publications and source records attributed to Z Shen.

At least 181 records · Page 10Linked to original sources
PubMed1998

[Experimental study of long-term result from reconstruction of vertebral artery].

Occlusive disease of first segment of vertebral artery is the common cause for insufficient supply of vertebro-basilar artery. The good result following reconstruction of vertebral artery was confirmed, but the long-term result was not certain. In order to investigate the long-term result, 23 dogs with established model of VA occlusion were studied. The occlusion was reconstructed by a by-pass operation between the common carotid artery and VA, then the quantitative methods were used to monitor the results for 3 months following operation. The results showed that 1. according to DSA, the anastomosis remained potent and the collateral circulations were established; 2. the hemodynamics of blood flow in VA kept well and the blood supply was stable by color ultrasonic Doppler; 3. the blood supply of cerebellum was increased 15.86% compared with that observed just after operation by hydrogen clearance method; and 4. no infarction focus was founded from MRI. The conclusion was that the result suggested that the long term result demonstrated was satisfactory after VA reconstruction for occlusive disease and the blood supply of the cerebellum was also better than that just following operation.

Animals↗
PubMed1998

[Experimental high-voltage electrical burns on limbs of rabbits].

OBJECTIVE: The study was designed to investigate the changes in some rheological parameters and ET-1 in venous blood following electrical burns. METHODS: One of the hind limbs of rabbits was subjected to 3000 V, 2.5 A charge of alternative electric current for 3 seconds. Rheological parameters such as red cell deformability (RED) and platelet aggregation rate (PAR), as well as endothelin-1 (ET-1) in venous blood drained from electrical burn wounds and contents of ATP in damaged muscle were measured at time intervals of 2 h, 24 h, 48 h and 72 h postburn. RESULTS: The changes in the parameters mentioned above were significant following electrical injury. The administration of PGE1 showed an advantageous effect in prevention of thrombosis and muscle "progressive necrosis" through improvement in RCD, reduction of PAR and the content of ET-1 in local circulation. CONCLUSION: RCD, PAR and the content of ET-1 in local circulation changed significantly following electric injury and may play an important role in the process of "progressive necrosis". The potential use of PGE1 in the treatment of electrical injury is proposed.

Alprostadil↗
PubMed1998

[Restoration of elbow joint and its function by transposition of latissimus dorsi myocutaneous flap following serious high-voltage injury in upper limb].

OBJECTIVE: This is to introduce a method for repairing and restoring the elbow joints and their function of the patients suffering from serious high-voltage electric burns in upper extremity. METHODS: We designed the transposition of latissimus dorsi myocutaneous flap (MCF) to repair the wounds of elbow, as well as restore the joint's flexion function by the motor power of the muscle. This procedure salvaged the elbow joints, which would have to be amputated before. RESULTS: 8 cases, 10 limbs were involved. All flaps survived completely and 6 of them had primary healing while the other 4 flaps healed after dressing changing. The elbow joints and their functions were satisfactorily restored in 5 limbs and the functions were also regained through further elbow joint release procedures in 2 limbs. The other 3 limbs (2 cases) lost contact with us and so the results were not clear. CONCLUSION: This method has evident advantages and satisfactory results.

Adult↗
PubMed1998

[Chemosensitivity test for 170 human breast carcinoma samples].

We tested the in vitro sensitivity of 170 primary breast carcinoma samples to the anti-cancer drugs conventionally used in clinical chemotherapy. It was found that: 1. The high sensitivity rate (HSR) of breast carcinoma cells to 5-fluorouracil (5-Fu), mitomycin (MMC), cisplatin (DDP), adriamycin(ADM), methotrexate(MTX), vincristin(VCR), vepesid(VP-16), taxol, and vindesine(VDS) were 57.1%, 49.4%, 48.3%, 35.8%, 21.8%, 21.2%, 10%, 18.2% and 20.9%, respectively. The increase of HSR of cancer cells to 5-Fu, MMC, DDP, taxol was more significant than that of the other drugs tested (P < 0.05). 2. No correlation was shown between drug sensitivity and factors, i.e. pathological type, clinical type, expression of estrogen receptor (ER) and epithelium growth factor receptor(EGFR) for breast carcinoma (P > 0.05). 3. Cyclosporin A can increase part of the sensitivity of ADM-resistant breast carcinoma cells to ADM.

Adenocarcinoma↗
PubMed1998

[Correlation study of spontaneous apoptosis, PCNA, and p53 in esophageal squamous-cell carcinoma].

OBJECTIVE: To investigate the inter-relationships among spontaneous apoptosis, proliferative activity and p53 mutation in esophageal squamous-cell carcinoma. METHODS: In 30 previondy untreated patients with esophageal squamous-cell carcinoma, tissues were examined for apoptosis by in-situ TUNEL, PCNA by immunohistochemistry, p53 mutation by PCR-SSCP and immunohistochemistry. The number of apoptotic cells per 10 low-power microseopic fields was taken as the apoptotic index. RESULTS: Apoptotic index of cells with high proliferative activity was significantly higher than that of cells with low proliferative activity (P < 0.05). In tumors with p53 gene mutation, apoptotic index of cells with high proliferative activity and low proliferative activity was significantly different (P < 0.05). No significant differences were observed in apoptotic index in tumors positive and negative for p53 mutation as examined by PCR-SSCP or immunohistochemistry (P > 0.05). CONCLUSION: In squamous-cell carcinoma of the esophagus, cells with high proliferative activity are apt to undergo spontaneous apoptosis.

Apoptosis↗
PubMed1998

[Population-based cancer survival: an analysis of 16,922 cases].

OBJECTIVE: In the period of 1982-1991, 16,922 patients with cancers from 15 sites of Qidong population-based cancer registry were analysed for evaluation of cancer survival as well as different cancer control measures. METHODS: Observed survival rate (OS) was computed by the Kaplan-Meier method using EGRET statistical software package. Relative survival (RS) which is the ratio of the OS to the expected rate was calculated by using Qidong life table with respect to sex, age and calendar period of observation. RESULTS: The five-year OS for the 5 leading sites of cancers, liver, stomach, lung, oesophagus, and rectum were 1.8%, 11.6%, 3.0%, 3.3%, and 19.9%, respectively. The five-year RS for the 5 sites were 1.9%, 14.0%, 3.6%, 4.2%, and 23.7%, respectively, in which, 1.7%, 14.8%, 3.4%, 4.2%, and 26.0% for males, and 2.7%, 12.7%, 4.1%, 4.0%, and 22.0% for females, respectively. Female patients with breast cancer and cervix cancer had 5-year RS of 54.6% and 33.0%. CONCLUSION: Cancer survival rates for all sites are poor, in which that of the liver is the lowest, while that of the breast, the highest. The survivals of cancers for all sites, especially for breast, cervix, and leukaemia are seen to be lower than those of European countries except for oesophagus, pancreas and lung cancer which do not achieve improved survival both in developing and developed countries. There will be a long way to improve the total cancer survival, as well as the cancer treatment in the developing countries.

Adolescent↗
PubMed1998

[The effects of BDP on eosinophils in nasal secretions of the patient with allergic rhinilis].

The effects of beclomethasone dipropionate (BDP) on eosinophils in nasal secretions of the patients with allergic rhinilis was assaied under the laser scanning confocal microscopy and the technology of fluoresence. The scanning images displayed that fluoresence signal of the eosinophils intracellular RNA was significantly decreased after BDP treatment. The results showed that anti-inflammation funtion of BDP was realized by controlling the intracellular DNA translate to RNA.

Anti-Inflammatory Agents↗
PubMed1998

Lipoprotein (a) concentration and apolipoprotein (a) phenotype in subjects with type 2 diabetes mellitus.

OBJECTIVE: To investigate the apolipoprotein (a) [apo(a)] polymorphism in the patients with type 2 diabetes mellitus and its relationship with complications. METHODS: In this study, we tested apo(a) phenotype via modified Utermann and Guo method in the 40 non-diabetic controls and 176 subjects with type 2 diabetes and analyzed the relationship between apo(a) phenotypes and micro- and macrovascular complications, including nephropathy, neuropathy, retinopathy, hypertension, coronary heart disease and cerebral infarction. RESULTS: Among the 40 non-diabetic controls, the frequencies of S3S2, S4 and S4S2 were 20%, 70% and 10% respectively and the serum lipoprotein (a) [Lp(a)] level was 0.08 +/- 0.07 mg/L. While the frequencies of S2, S3, S3S2, S4, S4S2, S4S3 were 18.18%, 20.45%, 17.05%, 34.09%, 4.55% and 5.68% in the diabetics and the Lp(a) concentration was 0.13 +/- 0.11 mg/L, with significant difference between the diabetics and non-diabetic controls. In comparison with the diabetics without complications, the frequency of apo(a) phenotype significantly differed in patients with nephropathy, nephropathy, hypertension, coronary heart disease and cerebral infarction except for diabetic retinopathy. In comparison with patients with S2 phenotype, the levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG) and glycated hemoglobin A1c (HbA1c) were lower in patients with S4 phenotype. The concentration of Lp(a) and urine albumin index (Alb/Cr) were significantly different among diabetics with different apo(a) phenotype, the highest being in patients with S2, secondly S3, and the lowest S4. CONCLUSION: There were significant differences in the frequency of apo(a) phenotype between subjects with type 2 diabetes and non-diabetic controls, and also in diabetics with or without microvascular and macrovascular diseases. The underlying linkage might be microalbuminuria and insulin resistance.

Adult↗
PubMed1998

[Expression of class II major histocompatibility antigen and factor VIII related antigen in endothelial cells of blood vessels in malignant lymphomas].

OBJECTIVE: To determine the heterogenicity in the expression of class II major histocompatible antigen (HLA-DR), factor VIII related antigen (FVIIIRAg) and the biological behavior of vessel endothelial cells in malignant lymphoma. METHODS: Standard immunohistochemical method using antiserum of HLA-DR and FVIIIRAg were applied to detect heterogeneous expression of endothelial cells in 39 cases of malignant lymphomas using neonatal lymph nodes, normal adult lymph nodes and lymph node hyperplasia as the controls. RESULTS: Both HLA-DR and FVIIIRAg reactivity was found in blood vessels in neonate lymph nodes, normal adult lymph nodes and lymph node hyperplasia. Most vessels in Hodgkin's disease and T cell lymphoma had high endothelial post capillary venules (HEV), which expressed both FVIIIRAg and HLA-DR. In B cell lymphoma, most blood vessels are capillary-like microvessels, which expressed little or no HLA-DR, only expressing FVIIIRAg. CONCLUSIONS: The above results indicate that the endothelial cell of blood vessels in Hodgkin's disease and T cell lymphoma not only participate in immunoregulation but also in blood coagulation, whereas, those in B cell lymphoma only participate in blood coagulation.

Adult↗
PubMed1998

Pharmacokinetics of intravenous arsenic trioxide in the treatment of acute promyelocytic leukemia.

OBJECTIVE: To study the pharmacokinetics and metabolism of arsenic trioixide (As2O3) and its main side effects. METHOD: As2O3 was administered intravenously at the dose of 10 mg per day for the treatment of 8 relapsed acute promyelocytic leukemia (APL) patients. The arsenic content was measured by Gas-phase chromatography. RESULTS: The plasma maximal concentration (Cpmax) was 0.94 +/- 0.37 mg/L (x +/- s), time to peak concentration (Tp) was 4 hours, plasma distribution half-time (t1/2 alpha) and elimination half-time (t1/2 beta) were 0.89 +/- 0.29 hours and 12.13 +/- 3.31 hours, respectively. Apparent distribution volume (Vc) was 3.83 +/- 0.45 L, system clearance (CLs) was 1.43 +/- 0.17 L/h, and area under curve (AUC) was 7.25 +/- 0.97 mg.h/L. The continuous administration of As2O3 did not alter its pharmacokinetic behaviors. During As2O3 treatment, 24-hour arsenic content in urine accounted for 1%-8% of the daily dose (10 mg). When arsenic accumulation in hair and nail increased continuously, the peak concentration could be five to seven-fold higher than that of pre-treatment. Importantly, arsenic contents in both urine and hair or nail declined gradually after drug withdrawal. No bone marrow suppression or severe organ-impairment was found. CONCLUSION: As2O3 is a relatively safe and effective remedy in the treatment of patients with relapsed APL, in spite of certain degree of arsenic accumulation in some tissues.

Adolescent↗
PubMed1998

[Bacterial distribution and antimicrobial resistance monitoring of surgical infection].

OBJECTIVE: To study the antimicrobial resistance of surgical isolates in Wuhan area. METHOD: The diameters of the inhibition zones of surgical isolates around antibiotic susceptibility test discs at 13 hospitals in Wuhan were computerfiled and analysed by the software of "WHONET-3" according to NCCLS published in 1993. RESULT: A total of 957 surgical isolates were collected in 1996. S. aureus, P. aeruginosa, E. coli and CNS were the main microorganisms. 12.4% of S. aureus was resistant to oxacillin and to other antimicrobials as well. Most strains of Enterobacteriaceae were resistant to ampicillin, with a resistant rate of more than 75%, but 93% for klebsiella sp. Imipenem, ceftazidime, amikacin and ciprofloxacin were most active agents against Gram (-) bacilli including Enterobacteriaceae and glucose nonfermenters. CONCLUSION: Antimicrobial resistance should be seriously considered during surgical therapy and prophylaxis with antimicrobial agents. The tendency to antimicrobial resistance of clinical isolates should be followed up continuously.

Anti-Bacterial Agents↗
PubMed1997

Characterization of a novel gut-specific chitinase gene from the human malaria vector Anopheles gambiae.

Chitinases that function in the molting of the larval exoskeleton have been characterized previously. However, chitinase expression in an adult insect gut has not been described. Here we report on the initial characterization and cloning of a novel chitinase gene that is expressed specifically in the midgut of adult Anopheles gambiae females. Upon feeding, chitinase is secreted into the gut lumen as an inactive pro-enzyme that is later activated by trypsin. Thus, temporal regulation of chitinase activity is tightly coupled to the temporal pattern of trypsin secretion. The enzyme may play a role in structuring the chitin-containing extracellular peritrophic matrix, whose formation is also induced by feeding. A chitinase cDNA was cloned from a library enriched for gut-specific sequences. The open reading frame encodes a 525-amino acid protein comprised of a putative catalytic domain at the N terminus, a putative chitin-binding domain at the C terminus, and a threonine/serine/proline-rich amino acid stretch in between them. Northern analysis indicates that this chitinase is expressed exclusively in the guts of adult females and not in adult carcasses or in any larval or pupal tissues. The present findings suggest the possibility of using this chitinase as an antigen for a malaria transmission-blocking vaccine.

Amino Acid Sequence↗
PubMed1997

Comparison of three-dimensional echocardiographic assessment of volume, mass, and function in children with functionally single left ventricles with two-dimensional echocardiography and magnetic resonance imaging.

Diminished systolic function or inappropriate hypertrophy are considered risk factors for outcome following the Fontan procedure. These parameters are difficult to assess in univentricular hearts that do not conform to the uniform shapes prescribed by conventional 2-dimensional imaging volume algorithms. Three-dimensional echocardiography requires no geometric assumptions and has been validated in both normal and distorted left ventricles. To assess the feasibility and accuracy of this technique in patients with univentricular hearts, we compared 2- and 3-dimensional echocardiographic estimates of ventricular volume, ejection fraction, and mass in patients with functionally single left ventricles with results obtained by magnetic resonance imaging (MRI). Twelve patients with functionally single left ventricles (6 months to 22 years) underwent examination by all 3 modalities. Correlation and agreement with MRI were calculated for volumes, ejection fraction, and mass. Three-dimensional echocardiographic comparison with MRI yielded a bias of 3.4 +/- 5.5 ml and 14.2 +/- 8.3 ml for systolic and diastolic volumes, respectively. Agreement analysis for mass showed a bias of 5.8 +/- 8.4 grams. Two-dimensional echocardiography showed less agreement for both volumes and mass (bias of -2.9 +/- 8.1, 2.9 +/- 10.4 ml and -8.3 +/- 12.0 g for volume and mass, respectively, p >0.05). Ejection fraction by 3-dimensional echocardiography showed significantly closer agreement with MRI (bias of 4.4 +/- 5.3%) than 2-dimensional echocardiography (bias of 8.5 +/- 10.3%, p = 0.04). Thus, 3-dimensional echocardiography provides estimates of ventricular volumes, ejection fraction, and mass that are comparable to MRI in this select group of patients with single ventricles of left ventricular morphology.

Adolescent↗
PubMed1997

Hydrodynamic properties of Vibrio harveyi acyl carrier protein and its fatty-acylated derivatives.

The amino acid sequence of Vibrio harveyi acyl carrier protein (ACP) is 86% identical to that of Escherichia coli ACP, although five nonconservative amino acid differences are concentrated in the loop region between helices I and II (residues 18-25). We have investigated the influence of these sequence differences on the hydrodynamic properties of the two ACPs and their fatty acylated derivatives. Hydropathy analysis suggests that V. harveyi ACP is more hydrophobic than E. coli ACP in the loop region, a prediction supported by stronger binding of V. harveyi acyl-ACPs (C12 to C16) to octyl-Sepharose. Gel filtration experiments indicated that both ACPs undergo a similar conformational expansion when pH was elevated from 7.5 (R(s) = 24 A) to 9.0 (R(s) = 30 A). Fatty acylation reversed this expansion: R(s) for 16:0-ACP was 12 A, independent of ACP source and pH. By contrast, V. harveyi and E. coli ACPs exhibited distinct gel electrophoretic properties. Fatty acylation of V. harveyi ACP produced a greater increase in mobility on a conformationally sensitive native gel system. Moreover, while both V. harveyi and E. coli ACPs migrated anomalously at 20 kDa on SDS-polyacrylamide gel electrophoresis, they exhibited strikingly different behavior on SDS gels upon acylation with longer chain fatty acids. These results indicate that E. coli and V. harveyi ACPs exhibit similar overall pH- and fatty acid-dependent conformational changes, but gel electrophoresis is more sensitive to structural differences due to variations of hydrophobicity and charge.

Acyl Carrier Protein↗
PubMed1997

Effects of epidermal growth factor and insulin on the activity of N-acetylglucosaminyltransferase V.

When quiescent rat hepatocellular carcinoma 7919 cells were treated with epidermal growth factor (EGF) or insulin (stimulators of receptor tyrosine kinase activity), the activity of N-acetylglucosaminyltransferase V was increased. The effect of EGF reached a maximum after 10 min and remained high for 30 min, while the effect of insulin reached a maximum after 5 min and decreased after 15 min. Preincubation of the cells with 1-O-octadecyl-2-O-methylglycerophosphocholine (Et18-OH3), which blocked the activation of mitogen-activated protein kinase by EGF, also blocked the activation of N-acetylglucosamyltransferase V by this hormone, whereas the activation of N-acetylglucosamyltransferase V by insulin could not be blocked by Et18-OH3. Our results suggest that N-acetylglucosamyltransferase V may be regulated by different receptor protein tyrosine kinase pathways.

Animals↗
PubMed1997

Cloned dendritic cells can present exogenous antigens on both MHC class I and class II molecules.

Pathways for presenting proteins from the extracellular fluids on MHC class I molecules have been described in macrophages. However, it is uncertain whether similar mechanisms exist in dendritic cells, because conventional preparations of these cells can be contaminated with macrophages. We addressed this issue by transducing granulocyte-macrophage CSF into bone marrow cultures followed by supertransfection with myc and raf oncogenes. These immortalized clones displayed dendritic morphology, and many expressed the dendritic cell-specific markers DEC-205 and 33D1 as well as high levels of MHC molecules and costimulatory molecules. Using these cloned dendritic cells, we found that exogenous OVA could be presented on both their MHC class I and class II molecules. This presentation was markedly enhanced when the Ag was particulate and internalized by phagocytosis. Presentation of particulate OVA on MHC class I molecules was insensitive to the weak base chloroquine, but was blocked by peptide aldehyde inhibitors of the proteasome, indicating that the class I-presented peptides were generated in the cytosol. Brefeldin A, which inhibits the exocytosis of newly synthesized proteins from the endoplasmic reticulum, also inhibited Ag presentation. These results establish that dendritic cells can present exogenous Ags on MHC class I molecules and appear to use a similar phagosome to cytosol pathway as macrophages. Therefore, dendritic cells are likely to play an important role in generating immune responses to tissue transplants and tumors in vivo. Furthermore, these findings provide an approach for targeting vaccine Ags into these cells to prime immune responses in vivo.

Animals↗
PubMed1997

cAMP increases apical IsK channel current and K+ secretion in vestibular dark cells.

Adenosine 3',5'-cyclic monophosphate (cAMP) is known to stimulate exogenous IsK channel current in the Xenopus oocyte expression system. The present study was performed to determine whether elevation of cytosolic cAMP in a native mammalian epithelium known to secrete K+ through endogenously expressed IsK channels would stimulate K+ secretion through these channels. The equivalent short circuit current (Isc) across vestibular dark cell epithelium in gerbil was measured in a micro-Ussing chamber and the apical membrane current (IsK) and conductance (gIsK) of IsK channels was recorded with both the on-cell macro-patch and nystatin-perforated whole-cell patch-clamp techniques. It has previously been shown that Isc can be accounted for by transepithelial K+ secretion and that the apical IsK channels constitute a significant pathway for K+ secretion. The identification of the voltage-dependent whole-cell currents in vestibular dark cells was strengthened by the finding that a potent blocker of IsK channels, chromanol 293B, strongly reduced IIsK from 646 +/- 200 to 154 +/- 22 pA (71%) and gIsK from 7.5 +/- 2.6 to 2.8 +/- 0.4 nS (53%). Cytoplasmic cAMP was elevated by applying dibutyryl cyclic AMP (dbcAMP), or the phosphodiesterase inhibitors 3-isobutyl-1-methylxanthine (IBMX) and Ro-20-1724. dbcAMP (1 mM) increased Isc and IIsK from 410 +/- 38 to 534 +/- 40 microA/cm2 and from 4.3 +/- 0.8 to 11.4 +/- 2.2 pA, respectively. IBMX (1 mM) caused transient increases of Isc from 415 +/- 30 to 469 +/- 38 microA/cm2 and Ro-20-1724 (0.1 mM) from 565 +/- 43 to 773 +/- 58 microA/cm2. IBMX increased IIsK from 5.5 +/- 1.5 to 16.9 +/- 5.8 pA in on-cell experiments and from 191 +/- 31 to 426 +/- 53 pA in whole-cell experiments. The leak conductance due to all non-IsK channel sources did not change during dbcAMP and IBMX while 293B in the presence of dbcAMP reduced IIsK by 84% and gIsK by 62%, similar to unstimulated conditions. These results demonstrate that the cAMP pathway is constitutively active in vestibular dark cells and that the cAMP pathway stimulates transepithelial K+ secretion by increasing IsK channel current rather than by altering another transport pathway.

1-Methyl-3-isobutylxanthine↗