Biomedical subjects

T Zhang

Publications and source records attributed to T Zhang.

At least 145 records · Page 8Linked to original sources

PubMed2000

Gastrin-mediated alterations in gastric epithelial apoptosis and proliferation in a mastomys rodent model of gastric neoplasia.

BACKGROUND/AIMS: Hypergastrinemia secondary to low acid secretion is associated with gastric carcinoid formation in Mastomys. We investigated the effect of gastrin on oxyntic epithelial apoptosis and proliferation in this model. METHODS: Hypergastrinemia and mucosal hyperplasia were induced by irreversible H(2) receptor blockade with loxtidine. Gastrin levels were normalised in some animals by 10 days' loxtidine withdrawal. Serum gastrin was determined by radioimmunoassay, proliferative, enterochromaffin-like cells and Bcl-2 protein family expression by immunohistochemistry, and apoptotic cells by terminal deoxyuridine nucleotide nick end labeling (TUNEL). RESULTS: Proliferating cells were increased 4-fold in loxtidine-treated animals, and returned to normal upon loxtidine withdrawal. Enterochromaffin-like cell number increased 2-fold with loxtidine, and did not decrease after withdrawal. Apoptotic epithelial cells were located at the luminal surface and increased 1.8-fold with loxtidine, returning to control levels upon withdrawal. The ratio of proliferative to apoptotic cells was lower in the control and withdrawn groups than in the loxtidine group (0.26+/-0.05 and 0.26+/-0.08 vs. 0.77+/-0.12). With hypergastrinemia, the expression of Bcl-2 and Bak was increased and Bax decreased in the middle of the gland. CONCLUSION: Hypergastrinemia is associated with alterations in both proliferation and apoptosis in Mastomys gastric mucosa. This may contribute to the pathogenesis of mucosal hyperplasia in this model.

Animals↗

PubMed2000

Prognostic impact of trisomies of chromosomes 10, 17, and 5 among children with acute lymphoblastic leukemia and high hyperdiploidy (> 50 chromosomes).

PURPOSE: Children with acute lymphoblastic leukemia (ALL) and high hyperdiploidy (> 50 chromosomes) have improved outcome compared with other ALL patients. We sought to identify cytogenetic features that would predict differences in outcome within this low-risk subset of ALL patients. MATERIALS AND METHODS: High-hyperdiploid ALL patients (N = 480) were enrolled between 1988 and 1995 on Children's Cancer Group (CCG) trials. Karyotypes were determined by conventional banding. Treatment outcome was analyzed by life-table methods. RESULTS: Patients with 54 to 58 chromosomes had better outcome than patients with 51 to 53 or 59 to 68 chromosomes (P = .0002). Patients with a trisomy of chromosome 10 (P<.0001), chromosome 17 (P = .0002), or chromosome 18 (P = .004) had significantly improved outcome compared with their counterparts who lacked the given trisomy. Patients with a trisomy of chromosome 5 had worse outcome than patients lacking this trisomy (P = .02). Patients with trisomies of both chromosomes 10 and 17 had better outcome than those with a trisomy of chromosome 10 (P = .09), a trisomy of chromosome 17 (P =.01), or neither trisomy (P<.0001). Multivariate analysis indicated that trisomy of chromosome 10 (P = .001) was the most significant prognostic factor for high-hyperdiploid patients, yet trisomy of chromosome 17 (P =.02) or chromosome 5 (P = .01) and modal chromosome number (P = .02) also had significant multivariate effects. CONCLUSION: Trisomy of chromosomes 10 and 17 as well as modal chromosome number 54 to 58 identify subgroups of patients with high-hyperdiploid ALL who have a better outcome than high-hyperdiploid patients who lack these cytogenetic features. Trisomy of chromosome 5 confers poorer outcome among high-hyperdiploid patients.

Child↗

PubMed2000

Sequencing a specific kinetoplast DNA fragment of Leishmania donovani for polymerase chain reaction amplification in diagnosis of leishmaniasis in bone marrow and blood samples.

A set of oligonucleotide primers I and II was developed by analyzing the specificity of a cloned kinetoplast DNA (kDNA) fragment of Leishmania donovani and sequencing the fragment. Polymerase chain reaction (PCR) was conducted with the primers to amplify a minicircle kDNA fragment (297 bp) to detect L. donovani in the bone marrow (22 samples), whole blood (16 samples), and serum (17 samples) of 22 patients with visceral leishmaniasis. All of 22 patients were diagnosed by microscopic identification. Control samples of bone marrow, whole blood, and serum were obtained from patients with leukemia and from healthy volunteers. In addition, 12 dogs were infected with L. donovani promastigotes for the PCR test. The total number of patients positive by PCR testing was 95.5% (21/22), with 91.0% (20/22) from the bone marrow, 68.8% (11/16) from the blood, and 29.4% (5/17) from the sera. Similar results were obtained in infected dogs. No amplification products were seen in control samples from humans or dogs. Our results suggest that PCR may be useful in detecting kDNA in the bone marrow and blood of patients with visceral leishmaniasis.

Animals↗

PubMed2000

A laser scanning confocal microscopy method. Simultaneous detection of intracellular Ca2+ and apoptosis using Fluo-3 and Hoechst 33342.

OBJECTIVE: To develop a simple and direct method to simultaneously determine apoptotic cells from a treated population of cells and detect the changes of intracellular Ca2+ in these apoptotic cells, in particular single ones, by confocal microscopy. STUDY DESIGN: MGC-803 cells treated with As2O3 were used as the double-staining cell model with Hoechst 33342 as a DNA probe and Fluo-3AM as a Ca2+ indicator. MGC-803 cell apoptosis induced by As2O3 was first demonstrated by DNA ladder in gel electrophoresis. Based on the difference in DNA stainability with Hoechst 33342 and corresponding fluorescence intensity between live and apoptotic cells, apoptotic cells and the changes in intracellular Ca2+ were detected at the same time by confocal microscopy. No necrotic cells in the group treated with As2O3 were found by the trypan blue exclusion test. RESULTS: The results from confocal microscope detection showed that intact and apoptotic cells were successfully recognized and the changes of intracellular Ca2+ in apoptotic and intact cells were simultaneously detected in the same sample. CONCLUSION: We provided a useful method to exactly detect changes in intracellular Ca2+ in apoptotic cells, especially in single ones, by confocal microscopy and to exclude the artifact effect of necrotic and intact cells.

Aniline Compounds↗

PubMed2000

[Detection for anti-Hantavirus IgM in patient serum with silver enhanced dot immunogold filtration assay].

OBJECTIVE: To establish a more rapid and simple method for detecting anti-Hantavirus IgM in patient' s serum. METHODS: A silver enhanced dot immunogold filtration assay (SEDIGFA) was developed by coating the nucleocapsid protein of Hantavirus on nitrocellulose (NC) membrane, adding colloidal gold labeled sheep anti-human IgM antibody and the silver enhancer. The whole procedure can be finished within 10 minutes. RESULTS: The coincidence rate of the results of serum samples simultaneously operated with ELISA and SEDEIGFA was 98% for anti-Hantavirus IgM. CONCLUSIONS: SEDIGFA is more simple and rapid for application to small medical laboratories. It can be applied for early diagnosis of hemorrhagic fever with renal syndrome (HFRS).

Gold Colloid↗

PubMed2000

Effect of superantigen on ion electrophysiology and permeability in rabbit maxillary sinus epithelia.

OBJECTIVE: Superantigens are potent inflammatory stimuli which derive from pathogenic microbes such as bacteria, viruses and protozoa. The aim of this study was to investigate the role of superantigens on the function of rabbit maxillary sinus epithelium. METHODS: Twenty New Zealand white rabbits were divided into 4 groups. Rabbit sinus mucosa was separated under a surgical microscope and mounted in Ussing chambers to record short circuit current, conductance and permeability to horseradish peroxidase (HRP). Group A was used as normal control. Group B was stimulated with an injection of superantigen into the sinus for 4 hours. The sinus mucosa of Group C was stimulated by the addition of tumor necrosis factor alpha (TNF-alpha) into Ussing chambers. Group D sinus mucosa was stimulated by superantigen after pretreatment with anti-TNF-alpha antibody. RESULTS: Superantigen evoked increases in sinus epithelial cell baseline short circuit current, conductance and permeability to HRP stimulated by the addition of TNF-alpha into Ussing chambers. These were similar to results from superantigen stimulation in vivo. The effect of superantigen on sinus epithelial cells could be blocked by pretreatment with anti-TNF-alpha antibody. CONCLUSIONS: Superantigen affected the function of sinus epithelial cells, including the capability of epithelial defensive barrier, which might be mediated by TNF-alpha.

Animals↗

PubMed2000

Multicenter clinical trial using an accelerated streptokinase regimen in patients with acute myocardial infarction.

OBJECTIVE: To observe the clinical efficacy and safety of intravenous thrombolytic therapy using an accelerated streptokinase (SK) regimen in acute myocardial infarction (AMI). METHODS: Data were collected from 40 hospitals during April 1996 to July 1997. Clinical therapeutic efficacy, five-week mortality, and adverse events were analyzed in 527 patients with AMI treated with an accelerated SK regimen (1.5 million IU within 30 min). RESULTS: The reperfusion rate of infarct-related arteries (IRAs) was 79.7% (421/528) assessed by clinical signs. The total mortality in the first 5 weeks was 6.6% (35/527). The incidence of allergic reactions and hypotension was 3.8% (20/528) and 4.2% (22/528), respectively. The incidence of bleeding was 2.7% (14/528), including cerebral bleeding 0.8% (4/528) and other major bleeding 0.8% (4/528). CONCLUSION: Intravenous accelerated SK therapy can markedly improve reperfusion rate without increasing adverse events such as bleeding, allergic reactions and hypotension.

Aged↗

PubMed2000

[Therapeutic effect of interleukin-12 on murine infection with Mycobacterium tuberculosis through modulating Th1 and Th2 cytokine balance].

OBJECTIVE: To study the effect of IL-12 on cytokines of murine infection with Mycobacterium tuberculosis. METHODS: 42 BALB/c mice infected with Mycobacterium tuberculosis were randomized into normal control (PBS) and IL-12 (n = 21) groups, treated with PBS or IL-12 respectively. Blood level of IFN-gamma, IL-4, and IL-10 were detected with ELISA method. The numbers of viable bacteria in organs were counted. Survival rate after treatment was investigated. RESULTS: In IL-12 group, none was dead. The numbers of viable bacteria in lung, liver and spleen were (227 +/- 107) x 10(5) cfu/ml, (4 +/- 3) x 10(5) cfu/ml and (1.5 +/- 0.5) x 10(5) cfu/ml respectively. INF-gamma (1,090 +/- 406) pg/ml. In PBS group, 8 mice were dead. The numbers of viable bacteria in lung, liver and spleen were (659 +/- 405) x 10(5) cfu/ml, (23 +/- 19) x 10(5) cfu/ml and (10.8 +/- 3.5) x 10(5) cfu/ml respectively. IFN-gamma (548 +/- 214) pg/ml. There was significant difference between those two groups. No change of the level of IL-4 in two groups. CONCLUSIONS: IL-12 induced IFN-gamma production, promoted development of Th1 cell responses, modulated Th1 and Th2 cytokine balance, suggesting that IL-12 enhance the host defense against the infection.

Animals↗

PubMed2000

[The construction of three-dimensional finite element model of human maxillary complex].

OBJECTIVE: To develop a method to construct three dimensional finite element (3-D FE) model which may express biomechanic dynamic state characters of normal maxillary complex. METHODS: SCT image reconstruction technique, digital image transfer and transcription and 3-D FEM were used in combination with self programming and ANSYS soft ware. RESULTS: A 3-D FE model of normal maxillary complex is constructed. The elements and nodes of the model are 2,602 and 4,595. CONCLUSION: The method to develop a model of maxillary complex adopting SCT 3-D image reconstruction technique, image transfer and transcription, and 3D FEM are feasible and effective.

Computer Simulation↗

PubMed2000

[Detecting the level of Actinobacillus actinomycetemcomitans leukotoxin].

OBJECTIVE: To detect the level of Actinobacillus actinomycetemcomitans (Aa) leukotoxin and distinguish the highly and the minimally toxic strains. METHODS: The polymerase chain reaction (PCR) assay was used to detect the difference of the nucleotide sequence of Aa leukotoxic promoter. 68 Aa isolates were examined, including 17 serotype b, 42 serotype c and 9 serotype a strains. The positive control strains were the highly toxic strain JP2 and 7 minimally toxic strains such as ATCC43717; the negative control strains were 12 other species of reference strains. RESULTS: The PCR fragments of JP2 was about 492 bp and that of the other Aa reference strains and 68 clinical isolates were 1,022 bp. PCR products not found in 12 other species. CONCLUSION: All of the 68 clinical isolates were minimally toxic strains.

Adolescent↗

PubMed2000

[Digital dental radiographic technique and its clinical application].

OBJECTIVE: To investigate the digital dental radiographic technique and its clinical application. METHODS: One hundred and five dental films were taken in 88 cases with the digora digital radiographic system and studied. RESULTS: The digora system has more advantages than the conventional dental radiographic technique. The image plate was used instead of the films and shorten exposure time. It had high exposure tolerances and image processing functions. CONCLUSIONS: This new imaging system applied in the clinics and research work can play an important role in improving the diagnostics.

Humans↗

PubMed2000

[In vitro model of hyperacute rejections in swine to human xenotransplantation].

OBJECTIVE: To evaluate the efficiency of inhibiting hyperacute rejections in swine to human xenotransplantation through expressing human CD(59) protein on the membrane of cultured pig aortic endothelial cells (PAECs) by transgenic methods. METHODS: The cultured PAECs and human umbilical vein endothelial cells (HUVECs) were identified by fluorescent and immunohistochemical methods. The constructed eukaryorotic expression vectors containing the human CD(59) cDNA, LXSN-CD(59) were identified by the methods of restriction endonucleases cleavage, agarose gel electrophoresis, and polymerase chain reaction. LXSN and LXSN-CD(59) were transfected into the PAECs separately with lipofectinmine mediated method. Stable transfectants were selected using G418. Cells expressing maximum human CD(59) protein were selected by FACS. These clones were incubated with the media containing human serum or monkey serum. The LDH released into the media was measured to assess the function of the hCD(59) protein. RESULT: Comparing with the control cells, we found that the cells expressing the human CD(59) protein released less LDH when they were incubated with human serum or monkey serum (P < 0.01). CONCLUSION: Hyperacute rejections may be inhibited through expressing the human complement regulatory protein CD(59) on the membrane of PAECs by transgenic methods.

Animals↗

PubMed2000

[Photodynamic therapy of hematoporphyrin derivative on human pancreatic carcinoma cell lines].

OBJECTIVE: To observe the effect of photodynamic therapy (PDT) on human pancreatic carcinoma cell lines in vitro. METHODS: Two lines of human pancreatic carcinoma cell P3 and SW1990 were studied to investigate the killing role of PDT with hematoporphyrin derivative (HPD) as photosensitizer and sodium lamp as light source. The cultured cells were treated with serial concentrations of HPD followed by irradiation of different dosages of visible light, then MTT colorimetric assay was applied to measure the relative inhibitory rate of PDT for the cells. RESULTS: The relative inhibitory rate of PDT for the cells elevated along with the increase in the concentration of sensitizer and dose of light. Under the low photodynamic dose, it increased rapidly, and gradually slowed down to reach the plateau. Under the same photodynamic dose, significant difference in the inhibitory rate between the two lines was observed (P < 0.01), and the LD90 was also different. CONCLUSIONS: PDT has a significant killing effect on human pancreatic carcinoma cell lines in vitro, and its relative inhibitory rate appears to be correlated with the dose of sensitizer and light irradiation. The sensitivity of the two cell lines to PDT is different.

Cell Line, Tumor↗

PubMed2000

[Study on the epidemiological features of Kawasaki disease in Jiangsu].

OBJECTIVE: To investigate the incidence of Kawasaki disease and epidemiological characteristics in Jiangsu province. METHODS: Questionnaire and diagnostic guidelines for Kawasaki disease with color - printed photographs of typical clinical symptoms were sent to all county hospitals with pediatric beds. All the in - patients with Kawasaki disease hospitalized from January, 1993 to December, 1997 were studied regarding age, sex, season of illness, cardiac sequelae, outcome etc. RESULTS: There were 509 cases (329 males and 180 females) diagnosed with 489 cases (96%) clinically typical. The incidence of the 5 - year period was averaged 2.53 per 100,000 children under 5. The number of male patients with Kawasaki disease was higher than that in female. The age peak of incidence was between 6 month and 2 - year olds. 13.6% of all cases developed cardiac sequelae which mostly occurred in males and in those younger than 2 years of age. There was one patient recurred among total patients reported (recurrence rate 0.2%) and 2 patients died (fatality rate 0.4%). CONCLUSION: The epidemiological characteristics of Kawasaki disease in Jiangsu province were similar to those in Japan in sex, season distribution and cardiac sequelae. The number of patients in male was higher than in female. Patients were more commonly seen in spring than in winter. However, the incidence rate in Jiangsu was significantly lower than that in Japan and the age peak was between 6 month and 2 years old.

Adolescent↗

PubMed2000

[Epidemiological and clinical characteristics of Kawasaki disease in Shanxi province].

OBJECTIVE: The objective of this paper is to describe the epidemiological and clinical characteristics of Kawasaki disease (KD) in Shanxi province, China during a 5 year - period from January 1993 to December 1997. METHODS: A province - wide epidemiological survey on Kawasaki disease (KD) was carried ont by the China - Japan Kawasaki disease study group. The questionnaire form and the diagnostic criteria of KD which was prepared by the Japan Kawasaki disease research committee and translated into Chinese were sent of the departments of pediatrics of all the hospitals with 100 or more beds in Shanxi province. All the KD patients who were diagnosed during the observation period from 1993 to 1997 were asked to report to this survey. The database of reported KD in this survey was analyzed at the Department of pediatrics of the Shanxi provincial people's hospital, Xian, China. All the patients that satisfied the diagnostic criteria were included. RESULTS: A total of 105 (70%) hospitals responded and 376 cases of KD were confirmed. More cases were reported in 1993 and 1994. Of the total patients reported, 69% were children under 3 years old with male to female ratio of 1.6:1. The proportion of patients with cardiac sequelae was 19% with male to female ratio: 3:1. There were 4 fatal cases with a fatality rate of 1%. CONCLUSIONS: Since KD is common in China continuous surveillance is necessary to maintain high awareness of KD so as to identify possible risk factors and its association with other disease.

Adolescent↗

PubMed2000

[Antisense oligonucleotides resistance to coxsackievirus B3 infection in HeLa cells].

OBJECTIVE: Antisense oligodeoxynucleotides (ODNs) hold great promise as therapeutic agents for the treatment of many human diseases. Oligonucleotides specifically hybrid with a selected sequence of RNA or DNA and inhibit the flow of genetic information DNA (or RNA) to proteins. In accordance with the present study, several oligonucleotide sequences that targeted CVB(3) RNA coding Vp(4), Vp(2), Vp(1), cleavage enzyme (P2A) or untranslational region were designed for observation. METHODS: Antiviral activities of these oligonucleotides were evaluated by plaque reduction assay and cytopathic effect (CPE). Cells were also treated with random oligonucleotides as a specificity control. RESULTS: Original ODNs, displaying sequence-specific inhibition ranging from 50% to 90% were identified. Three ODNs (at 5 microM concentration), which targeting at the pyrimidine - rich tract (S(CB1)), structural protein VP(1) (S(CB4)) and initiation of translation (S(CB2)) were shown to exhibit inhibition of viral infection 75% to 90% at 1 MOI. There was only low antiviral activity in S(CB5) and S(CB3), and random oligonucleotide were not found having antiviral activity. Oligonucleotides in this study were not toxic at 5 microM concentration. CONCLUSION: A better antiviral antisense oligonucleotides as S(CB1) and S(CB4), S(CB2), could provide candidate antisense oligonucleotides for the treatment of CVB(3) infection.

Antiviral Agents↗

PubMed2000

[Clinicopathologic study of angiogenesis in human hepatocellular carcinoma].

OBJECTIVE: To study clinicopathologic significance of microvessel density (MVD) and the expression of vascular endothelial growth factor (VEGF) in human hepato-cellular carcinoma (HCC). METHODS: 30 HCC cases with neighboring noncancerous tissues, 10 liver cirrhosis cases, 5 mild chronic hepatitis cases and 4 normal liver tissue samples were stained with CD34, VEGF by immunohistochemistry method. Quantitation of sinusoid-like vessels and semi-quantitation of VEGF expression were performed and analyzed in conjunction with the clinico-pathological features of HCC. RESULTS: All HCC tissues showed diffuse CD34 expression and its site of distribution was somewhat corresponding to the original structure of sinusoid-like pattern, while CD34 was negative in the "sinusoid" regions of normal and chronic liver disease. Both MVD and VEGF were correlated to portal vein invasion of HCC, MVD was also correlated to the tumor size. The MVD of tumor less than 2 cm in diameter was significantly lower than that of tumors with a diameter of 2 similar 5 cm. The positive rate of VEGF in HCC was 83.3%. The expression of VEGF was also remarkable in the neighboring noncancerous tissues in which inflammatory cell infiltration was apparent. CONCLUSIONS: MVD and expression of VEGF were remarkably increased in HCC. Both were correlated with portal vein invasion. VEGF derived from tumor cells and noncancerous tissues may be associated with the angiogenesis of HCC.

Adult↗

PubMed2000

[The expression of Fas antigen and plasma levels of sFas and sFasL in patients with aplastic anemia].

OBJECTIVE: To investigate the role of Fas/FasL system in the pathogenesis of aplastic anemia (AA) and its correlation with clinical status. METHODS: Plasma levels of sFas and sFasL and the expression of Fas antigen on mononuclear cell (MNC) membrane in 32 AA patients and 24 normal controls were assayed by ELISA and FACS, respectively. RESULTS: The percentage of CD(34)(+)Fas(+) cells was significantly higher (P < 0.05) in AA patients than that in normal controls, and the percentage of CD(34)(+)Fas(+) cells in severe AA patients was much higher than that in chronic AA patients (P < 0.05). The percentage of CD(34)(+)Fas(+) cells was negatively correlated with the course of disease. The levels of sFas were significantly lower (P < 0.05) in AA patients than that in normal controls, and the sFas levels in severe AA were much lower than those in chronic AA (P < 0.05). The percentage of CD(34)(+)Fas(+) cells was negatively correlated with sFas level. CONCLUSION: Fas/FasL system aberration is involved in the pathogenesis of AA.

Adolescent↗