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Biomedical subjects

Z Li

Publications and source records attributed to Z Li.

At least 343 records · Page 19Linked to original sources
PubMed2001

[The therapeutic effects and postoperative complications of cataract surgery in Laiwu City].

OBJECTIVE: To decrease the prevalence of blindness and low vision in Laiwu City. METHODS: The therapeutic effects and postoperative complications of each method of cataract surgery were investigated and statistically analyzed. The cases with postoperative complications were treated after surgery. RESULTS: In the investigation, 1,274 eyes of 1,089 cases had undergone cataract surgeries, including couching for cataract, intracapsular cataract extraction (ICCE), extracapsular cataract extraction (ECCE) and ECCE with intraocular lens implantation. The prevalence of blindness and low vision was 4.87% and 23.70%, respectively. There were postoperative complications in 650 eyes (51.02%). They were corneal decompensation, secondary glaucoma, opacity of posterior capsuler, cystoid macular edema and retinal detachment. After treatment for the postoperative complications, the prevalence of blindness and low vision was decreased to 1.96% and 6.01%, respectively. The cases having escaped the blindness and handicap after treatment were lowest in the groups of couching and ICCE. CONCLUSIONS: The survey on the population having undergone cataract surgery in rural district is important. The postoperative complications can be treated in time and the prevalence of blindness and low vision can be decreased.

Cataract↗
PubMed2001

[Changes of pulmonary function and partial oxygen pressure before and after bronchoalveolar lavage in patients with interstitial lung diseases].

OBJECTIVE: To study the influence of bronchoalveolar lavage(BAL) on pulmonary physiological function and partial oxygen pressure(PaO2). METHODS: Pulmonary function and partial oxygen pressure were measured in 42 patients with interstitial lung disease (ILD) before and after BAL, 7 non-smoker volunteers as control group. RESULTS: VC% and FEV1% decreased significantly from (74 +/- 17)% to (64 +/- 19)% and from (72 +/- 9)% to (65 +/- 12)%, respectively. PaO2 decreased from(77 +/- 11) mm Hg to (63 +/- 11) mm Hg. The above parameters were also decreased in control group, but had no statistical significance. CONCLUSION: Pulmonary physiological function and partial oxygen pressure of patients with ILD are influenced by BAL process.

Adult↗
PubMed2001

Antihypertension and anti-cardiovascular remodeling by phenylalanine in spontaneously hypertensive rats: effectiveness and mechanisms.

OBJECTIVE: To investigate mechanisms of anti-hypertension and anti-cardiovascular remodeling by phenylalanine (phe) in spontaneously hypertensive rats (SHRs). METHODS: The comparison of blood pressure (BP) increment with the ages and cardiovascular changes of SHRs was made between the 3% phe-intervented group (SHR-phe) and the control SHRs group. Detection of the structural changes with the VIDAS digital vedio-frequency processing technique and light and electron microscopy were made. The cell growth and proliferation of cultured smooth muscle cells (CSMCs) of the thoracic aortas or myocardial fibroblasts were evaluated by measuring the 3H-thymidine counts per minute (cpm) incorporated into the new synthesized desoxyribonucleic acid (DNA) and determining the cell number with the crystal violet stain technique. The Ca2+ influx was measured in counts/min of 45CaCl2 after incubating it with 5 different concentrations of phenylalanine and the intracellular [Ca2+]i by Fura-II/Am indicator. The total messenger ribonucleic acid (mRNA) of the myocardium was extracted and Northern blot analysis was performed with the probe collagen alpha 2 (I) cDNA. The tyrosine hydroxylase (TH) activity was measured by high-performance liquid chromatography (HPLC) with electrochemical detector after having reacted with its substrate tyrosine and other reagents. The catecholamine contents in brain homogenat were detected by HPLC method. The comparison of pharmacokinetics of phenylalanine among SHR-phe, SHRs and control Wistar Kyoto (WKY) rats was made after intravenous injection of 3H-L-phe (1 ml/kg) by PK-GRAPH Program for kinetic calculation. The 3H-L-phe uptake by CSMCs after incubating for definite intervals was also detected and compared. RESULTS: Phenylalanine could prevent the increase of BP with ages and the heart weight (heart/body weight index). The aortic media thickness and the collagen content in the myocardium were decreased significantly in SHR-phe. Whereas the dearranged cardiovascular structure was much improved. The mechanisms might be direct and specific inhibition of the DNA synthesis and proliferation of cardiovascular cells which may be related to the inhibition of collagen alpha 2(I) cDNA, c-fos and c-myc expression. Other mechanisms may include decrease of intracellular [Ca2+]i and an inhibition of central sympathetic activity due to the results of higher TH activity in the caudate nucleus and higher adrenaline content in the posterior hypothalamus. Besides, partial recovery of phenylalanine metabolic aberrants existed in SHRs seems to be another possibility for its effectiveness. CONCLUSIONS: Phenylalanine intervention could exert a definite anti-hypertension and anti-cardiovascular remodeling effects on SHRs like seen in human essential hypertension. Its mechanisms might be related to direct inhibition of growth in the cardiovascular cells, decrease of central sympathetic activity, the reverse of the exhibited phenylalanine metabolic aberrants in SHRs, and a decrement of intracellular [Ca2+]i.

Animals↗
PubMed2001

Increased activity of protein kinase C in alveolar macrophages in idiopathic pulmonary fibrosis.

OBJECTIVE: To investigate the changes on protein kinase C (PKC) activity of alveolar macrophages (AMs) in patients with idiopathic pulmonary fibrosis (IPF). METHODS: The PKC activity of AM in 9 healthy volunteers and 15 patients with IPF was investigated by measuring the radioactivity. RESULTS: The total, cytosolic and membrane PKC activity of AM in bronchoalveolar lavage fluid (BALF) from patients with IPF were higher than those from control group (P < 0.01, P < 0.05 and P < 0.05, respectively). The total and the membrane-associated PKC activity had a positive correlation with the number of cells in BALF (r = 0.8135, P < 0.01 and r = 0.5917, P < 0.05), respectively. CONCLUSION: As a bypass of transmembrane signal transduction, PKC was suggested to be involved in the origination and development of IPF.

Adult↗
PubMed2001

High level expression of human factor VIII in mammalian cells after retroviral-mediated gene transfer.

OBJECTIVE: To develop a retroviral-mediated high efficient expression system of human coagulation factor VIII. METHODS: The LNC-FVIIIBD retroviral vector was generated by cloning a human B-domain-deleted (760aa-1639aa) Factor VIII (FVIII) cDNA (FVIII cDNA BD) into the retroviral vector pLNCX. Several mammalian cell lines, including NIH3T3, CHO, Cos-7 and human hepatic cell line, L-02, were transduced with viral supernatant from the highest virus-producing PA317 clone. Antigen and coagulant activity of human FVIII in cell culture medium were measured by ELISA and a one-stage method, respectively. RT-PCR was performed for the detection of FVIIIBD mRNA. RESULTS: Human FVIII was expressed in all four target cells, with the highest FVIII expression observed in NIH3T3. The coagulant activity of secreted FVIII was up to 1.6 U/10(6) cells.24 hrs-1, and the FVIII antigen was 500 ng/10(6) cells.24 hrs-1. FVIII coagulant activity and antigen expressed by transduced CHO cells were 0.12 U/10(6) cells.24 hrs-1 and 62.4 ng/10(6) cells.24 hrs-1, respectively. Human FVIII expression was relatively low in Cos-7 and L-02 cells. RT-PCR results demonstrated transcription of FVIII cDNA BD in the target cells. CONCLUSIONS: The constructed retroviral vector was able to direct high level expression of human FVIII in various mammalian cell lines. It has potential utility in the future gene therapy for Hemophilia A.

Animals↗
PubMed2001

Comparison of CT virtual endoscopy with electronic colonoscopy in 30 colonic carcinoma patients.

OBJECTIVE: To evaluate the clinical application of CT virtual endoscopy (CTVE) in the diagnosis and treatment of colonic carcinoma. METHODS: We collected 30 patients pathologically proven to have colonic carcinomas as examined by CTVE and electronic colonoscopy (EC), correlating the CTVE and EC images respectively with surgical pathology in three aspects: tumor morphological features, degree of circumferential bowel wall involvement and longitudinal extent of tumor. RESULTS: CTVE imaging of colonic carcinomas showed morphological features: polypoid pattern (11 patients), ulcerative pattern (11), and infiltrative pattern (8); degree of circumferential bowel wall involvement: less than 1/2 (4 patients), from 1/2 to 3/4 (6), and more than 3/4 (20); and their longitudinal extent: 1.0-3.0 cm (7 patients), 31-5.0 cm (10), and 5.1-11.0 cm (13). Correlation of CTVE and EC with surgical pathology was found. Comparison of CTVE with surgical pathology showed tumor morphological features: concordant (26 patients), and disconcordant (4); degree of circumferential bowel wall involvement: concordant (25), disconcordant (5); and longitudinal extent of the tumor: concordant (23), disconcordant (7). Comparison of EC with surgical pathology showed tumor morphological features: concordant (22 patients), disconcordant (8); degree of circumferential bowel wall involvement: concordant (28), disconcordant (2); and longitudinal extent of the tumor: concordant (14), disconcordant (3), and undefined by EC (13). CONCLUSIONS: The images obtained by CTVE in colonic carcinoma are similar to those obtained by EC. CTVE is an excellent alternative to EC for patients who cannot tolerate EC and for cases with incomplete EC.

Adult↗
PubMed2001

Inherited disturbances of phenylalanine metabolic kinetics in essential hypertension.

OBJECTIVE: To clarify whether the disturbances in metabolic kinetics of the essential aminoacid, phenylalanine (phe), are implicated in the genetic pathogenesis of essential hypertension (EH). METHODS: 1. L-(2, 3D3)-leucine, L-(2, 3D3)-isoleucine, L-15N-lysine, L-(2, 3D3)-valine and L-(2, 3D3)-phe were used for simultaneously studying comparative metabolic kinetics using stable isotope tracer methods with a GC-MS system. Study groups were the offspring with both parents suffering EH (n = 10, FH+), 2 or more than 2 parents and grand-parents with EH and stroke (n = 12, FS+) and those without genetic predisposition of EH and stroke (n = 12, F) groups. 2. By comparing the radioactive counts of [3H]-phe, and their weight transformation in blood after 1.5 Ci/kg i.v. administration at defined intervals and in tissues obtained after being sacrified among spontaneously hypertensive rats (SHR), 2 kidney-1 clip hypertensive rats (2K1C) and their normotensive controls (WKY). 3. The time transport and concentration transport of [3H]-L-phe in cpm between the cultured vascular smooth muscle cell of 5th generation in SHR and WKY were compared. RESULTS: A single and unique disturbance of metabolic kinetics in phe were found in FH+, FS+ and SHR. The plasma pool or apparent volume of distribution was enlarged, and the turnover rate constants between plasma and cell tended to show a decrease. The pharmacokinetics of phe in 2K1C was not changed. Only phe content in heart and aorta, the vital organs for predicting BP, were higher in SHR than in WKY tissues studied. Both the time and concentration transport were higher in SHR, e.g., an increment in the net-uptake of L-phe by vascular tissue. CONCLUSION: A unique aberrant of metabolic kinetics of phe might be implicated in the inherited pathogenesis of EH and stroke both from clinical and animal studies.

Adult↗
PubMed2001

Molecular cloning and characterization of NAG-7: a novel gene downregulated in human nasopharyngeal carcinoma.

OBJECTIVE: To identify novel tumor suppressor genes at chromosome 3p24-26 in human nasopharyngeal carcinoma (NPC). METHODS: Twenty epithelial-derived expressed sequence tags (EST) were selected from chromosome 3p24-26. RT-PCR and Northern blot were used to detect the expression of the ESTs in NPC cell line, HNE-1, and primary cultures of normal nasopharyngeal epithelial cells. One EST, which was substantially downregulated in the HNE-1 cell line, was detected in 19 NPC biopsy samples. cDNA library screening was used to get its full sequence and the sequence of this novel gene was analyzed. RESULTS: A novel gene located at chromosome 3p25.3 was obtained and named NAG-7. It was downregulated in 26.3% (5/19) of NPC biopsy samples. Its 1677 bp full length cDNA had a potential open reading frame predicting a 94 amino acid protein with a molecular weight of 11,023.87 Dalton. Analysis of the NAG-7 gene showed that it was a transmembrane protein containing a protein kinase C phosphorylation site and a myristyl site. It has no significant homology to any reported genes in the database of GenBank. CONCLUSION: NAG-7 is a novel gene downregulated in NPC, suggesting that it may be involved in the development of NPC.

Amino Acid Sequence↗
PubMed2001

[Influence of staphylococcal enterotoxin A on immunogenicity of hepatocellular carcinoma cells].

OBJECTIVE: To transduce the gene of staphylococcal enterotoxin A (SEA) into a HCC cell line HHCC and to make the cells to express the molecules of SEA for the purpose of improving the immunogenicity and inducing immune rejection of HCC. METHODS: Construct retroviral vector containing the gene of SEA and transduce it into HHCC cells. Then the integration, transcription and expression of recombinant were analyzed. At last cytotoxicity test of peripheral blood mixed lymphocytes was carried out. RESULTS: We obtained the retroviral vector pLXSN-SEA, transduced into HHCC cells and obtained the HCC cell line that expressed SEA toxin protein. The content of SEA in supernatant was at the level of pg. The cytotoxicity of HHCC transduced with SEA by T lymphocytes was 45.6%, which was higher than that of HHCC (20.7%). The Km value of T lymphocytes against HHCC transduced with SEA and without SEA was 5.18 x 10(4) and 2.92 x 10(5), separately. The difference had statistical significance. CONCLUSIONS: After transducing the SEA gene, although tiny quantity of expression is detected, the cytotoxicity assay proves that the expression of SEA lead to a robust immune response.

Carcinoma, Hepatocellular↗
PubMed2001

[Cloning of drug resistance-related gene fragments differentially expressed on lung adenocarcinoma cell line A549 and its DDP-resistant counterpart A549DDP].

OBJECTIVE: To clone drug resistance-related genes of lung adenocarcinoma. METHOD: The difference in gene expression between A549 and A549DDP was identified by mRNA differential display technique. Genes differentially expressed were cloned and confirmed by Northern blot. RESULTS: Four cDNA fragments of differentially expressed genes were obtained and sequenced. Of the 4 cDNA fragments, 2 (A1 and D1) did not show sequence homology with the existing genes in the GeneBank, one (A2) was 89% homologous with interleukin 1 beta converting enzyme (ICE) gene, and the other (D2) was identical to mouse musculus 45s pre-rRNA (MM45srRNA) gene. Both cDNA fragments A1 and A2 were expressed in A549 but not or barely expressed in A549DDP, while fragments D1 and D2 were expressed in A549DDP but not in A549. CONCLUSION: Four differentially expressed gene fragments between lung adenocarcinoma cell line and its cisplatin-resistant counterpart were identified by mRNA differential display technique. It remains to be studied whether the newly identified gene fragments and those showing sequence homology to ICE and MM45srRNA are indeed positively or negatively related to drug resistance.

Adenocarcinoma↗
PubMed2001

[Expression of glutathione S-transferase-pi in human esophageal squamous cell carcinoma].

OBJECTIVE: To evaluate the expression of glutathione S-transferase-pi (GST-pi) in human esophageal squamous cell carcinoma (ESCC) and its correlation with the clinicopathological data. METHODS: Immunohistochemical method (labeled avidin biotin method) and ELISA were used to detect the expression of glutathione S-transferase-pi (GST-pi) in 143 cases of formalin fixed, paraffin embedded ESCC tissue sections. Serum GST-pi was determined before and after operation in 43 patients with ESCC. RESULTS: GST-pi was positively stained immunohistochemically in 58.7%(84/143) of ESCC and 79.6%(109/139) of surrounding noncancerous esophageal tissues (P < 0.05). The expression level of GST-pi was significantly higher in well differentiated than poorly differentiated carcinomas(P < 0.05). No significant correlation was observed between GST-pi levels and lymph node metastasis, pathological staging or long term survival. The preoperative and postoperative mean serum GST-pi levels in ESCC patients were significantly higher than those in 34 normal subjects (P < 0.05, P < 0.025); the mean serum GST-pi level in postoperative patients was lower than that in preoperative patients, but the difference was not significant. CONCLUSION: GST-pi is a useful tumor marker for human ESCC.

Adult↗
PubMed2001

[A comparative study of friction behaviour matching of natural tooth and new type dental prosthetic materials--titanium].

New type dental prosthetic materials Titanium not only have excellent biocompatibility, better corrosion resistance, appropriate hardness, light density approaching to human skeleton, but also good mechanical properties as those of type II, IV gold alloy recommended by ADAS, and their strength to weight ratio is 1.3 times that of aluminum, 1.5 times that of steel. Friction wear comparative tests of natural living teeth and dental Titanium materials have been carried out against Gr15 steel ball. A reciprocating movement was realized at the modified machine of fretting to simulate the pair of real tooth. The main test parameters were: slip amplitude 500 microns, normal load 20 N, frequency 2 Hz, and number of cycles 5000. The wear behavior results show that titanium is comparatively a prospective dental materials for restoration.

Child↗
PubMed2001

[Clinical analysis of 1,827 patients with reflux esophagitis].

OBJECTIVE: To investigate clinical and endoscopic characteristics of reflux esophagitis (RE) in Chinese. METHODS: 1 827 patients with RE, diagnosed by endoscopy in the past 10 years, were divided into different grades according to Los Angeles System and Chinese Standard. A part of them underwent esophageal manometry, 24-hour pH monitoring, and 24-hour bilirubin monitoring. The relationship between age, sex, symptom, accompanied diseases and each examinations were analyzed. RESULTS: RE was 2.02% of the total endoscopy number, and male vs female was 3.9:1, mean age was (52.02 +/- 14.38) years old. Only 36.29% of RE patients have typical reflux symptom. Patients with light mordent (Los Angeles System A, B and Chinese Standard I) RE were more than those with severe RE. Both of the time of esophageal acid exposure and total percent time bilirubin absorbance >or=0.14 for RE was significantly more than normal (P < 0.01). CONCLUSION: The incidence of RE in Chinese is lower than that in Western and the severity is less. Most of RE are male and aged. There is a close association between RE and both of gastroesophageal reflux and duodenogastroesophageal reflux. Endoscopy is very important for diagnosis of RE.

Adolescent↗
PubMed2001

[Effect of rheumatoid arthritis associated HLA-DRbeta1 subtypes on protein kinase A signaling].

OBJECTIVE: To investigate the impact of rheumatoid arthritis (RA)-associated HLA-DRbeta(1) (*)0401, (*)0402, (*)0403 and (*)0404 subtypes on protein kinase A (PKA) signaling. METHODS: To detect the activities of adenylate cyclase (AC), cAMP and PKA in transfectants expressing rheumatoid arthritis-associated HLA-DRbeta(1) subtypes and their mutants. RESULTS: The levels of AC, cAMP and PKA of HLA-DRbeta(1) (*)0401 and (*)0404 transfectants were significant lower than that of HLA-DRbeta(1) (*)0402 and (*)0403 transfectants (P < 0.01). The mutant HLA-DRbeta(1) (*)0403 transfectants expressing DRRAE or QRRAA secreted lower levels of PKA, cAMP and AC (P < 0.01). CONCLUSION: RA-associated HLA-DRbeta(1) (*)0401 and (*)0404 expression suppressed intracellular PKA signaling pathway, and may mediate abnormal intracellular signaling in rheumatoid arthritis.

Adenylyl Cyclases↗
PubMed2001

[Clinical analysis of 68 patients with ruptured sinus of Valsalva aneurysm].

OBJECTIVE: To evaluate the clinical characteristics, diagnosis, treatment and prognosis of ruptured aneurysm of the sinus of Valsalva (ASV). METHODS: Sixty-eight cases of ruptured ASV treated in our hospital from 1986 to 1998 were retrospectively analyzed. RESULTS: The ratio of male to female was 1.8:1 in 68 patients (44 males, 24 females). The mean age was (29.5 +/- 10.7) years (8-60 years). The proportion of ruptured aneurysms originating from the right coronary and noncoronary sinus was 79.4% and 20.6% respectively. Sixty-seven point six percent of ASV ruptured into right ventricle and 32.3% into right atrium. The incidence of ventricular septal defect and aortic valve insufficiency was 48.5% and 20.6% respectively. The former only existed in those patients whose ASV originating from the right coronary sinus and rupturing into right ventricles. There was a significant correlation between sudden onset of symptoms and fistulating of ASV into right atrium and a significant difference as compared with those fistulating into right ventricle (P < 0.001). Diagnostic sensitivity and specificity of echocardiography in ruptured ASV was 97.1% and 100% respectively, but the rate of missing subarterial ventricular septal defect was 24.2%. Sixty-seven patients received operation, one died of pulmonary embolism six weeks after operation. Thirty-six patients were followed up, the mean follow-up period was 6.5 years (range 1 to 16 years). Two patients were reoperated for leak of ventricular septal defect and aortic regurgitation. The cardiac function of sixteen patients were found to be of NYHA class I, seventeen of class II and three of class III. CONCLUSION: Echocardiography in combination with aortography is an accurate diagnostic method for ruptured ASV and the prognosis in majority of the patients operated in time is good.

Adult↗
PubMed2001

[Alterations of pulmonary surfactant during Pseudomonas aeruginosa pneumonia of immunocompromised rats].

OBJECTIVE: To analyze the alterations of pulmonary surfactant in immunocompromised host with Pseudomonas aeruginosa (PA) pneumonia. METHODS: 50 rats were randomly divided into two groups, one immunosuppressed with cyclophosphamide and cortisone acetate as ICH group, another as control group (CON), their lung tissue and bronchoalveolar lavage fluid (BALF) were collected before PA challenging and 3 h, 6 h, 9 h, 24 h after PA challenging intratracheally, wet/dry ratio (W/D) of lung tissue were measured, concentrations of total protein (TP), total phospholipids (TPL), disaturated phosphatidylcholine (DSPC) and surfactant protein A (SP-A) in BALF were analyzed. RESULTS: The ratios of DSPC/TPL and DSPC/TP decreased significantly in both ICH and CON groups after PA infection, there were not significant differences between the two groups, no change in the concentrations of TPL and DSPC. Concentration of SP-A and SP-A/TP in ICH group decreased remarkably 6 h after PA pulmonary infection than before [(1.8 +/- 1.1) microgram/ml vs (4.2 +/- 1.5) microgram/ml, (1.4 +/- 0.7) microgram/mg vs (11.7 +/- 8.1) microgram/mg, P < 0.05], meanwhile there were no significant alterations in CON group. W/D and TP concentrations increased in both groups after PA challenging, however the alterations were much greater in ICH group (P < 0.05). Alterations of SP-A appeared a negative correlation with alterations of TP and W/D (r = -0.793, P < 0.01, r = -0.769, P < 0.01). The ratios of SP-A/TPL and SP-A/DSPC decreased significantly 6 h after PA challenging than before, the ratios were much lower in ICH group than in CON group during 6 h-9 h after PA inoculation. CONCLUSION: After PA pulmonary infection, alterations of phospholipids could initially appear a relative decrement of DSPC during acute phase of infection, much remarkable decrease of SP-A in ICH group could be associated with the more severe lung injury, alterations of SP-A were more obvious than surfactant lipids in ICH.

Animals↗
PubMed2001

[Effect of various cavity design, lining and restorative materials on the fracture resistance of teeth].

OBJECTIVE: To evaluate the influence of various cavity designs, lining and restorative materials on fracture resistance of teeth in vitro. METHODS: Factorial design with three factors and various levels was used. 36 extracted human maxillary premalors were prepared for occlusal cavity, MO cavity and MOD cavity. Various base material and restorations were used. All teeth were thermocycled and mounted for testing and then were loaded until fracture. The results were analyzed by a three-way ANOVA. Fracture patterns were observed at the same time. RESULTS: There was significant difference in fracture resistance among various cavity designs and restorations. The fracture patterns were different. CONCLUSIONS: The different classes of cavities and various restorations have significantly influence upon fracture resistance of teeth. There are interactions between cavities and restorations.

Dental Cavity Lining↗