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Lin Zhang

Publications and source records attributed to Lin Zhang.

At least 289 records · Page 16Linked to original sources
PubMed2003

No PUMA, no death: implications for p53-dependent apoptosis.

More than a decade ago, it was found that one of the two essential physiological functions of p53 is to selectively destroy stressed cells through apoptosis. Despite the large number of studies describing p53-dependent apoptosis since then, how p53 turns on the apoptotic switch has remained enigmatic. In this issue of Cancer Cell, Jeffers et al. report that knockout of PUMA, a recently identified BH3-only Bcl-2 family protein, recapitulates virtually all apoptotic deficiency in p53 knockout mice. Their results indicate that PUMA is an essential mediator of p53-dependent and -independent apoptosis in vivo.

Animals↗
PubMed2003

Enzymes of adenosine metabolism in the brain: diurnal rhythm and the effect of sleep deprivation.

Adenosine plays a role in promoting sleep, an effect that is thought to be mediated in the basal forebrain. Adenosine levels vary in this region with prolonged wakefulness in a unique way. The basis for this is unknown. We examined, in rats, the activity of the major metabolic enzymes for adenosine - adenosine deaminase, adenosine kinase, ecto- and cytosolic 5'-nucleotidase - in sleep/wake regulatory regions as well as cerebral cortex, and how the activity varies across the day and with sleep deprivation. There were robust spatial differences for the activity of adenosine deaminase, adenosine kinase, and cytosolic and ecto-5'-nucleotidase. However, the basal forebrain was not different from other sleep/wake regulatory regions apart from the tuberomammillary nucleus. All adenosine metabolic enzymes exhibited diurnal variations in their activity, albeit not in all brain regions. Activity of adenosine deaminase increased during the active period in the ventrolateral pre-optic area but decreased significantly in the basal forebrain. Enzymatic activity of adenosine kinase and cytosolic-5'-nucleotidase was higher during the active period in all brain regions tested. However, the activity of ecto-5'-nucleotidase was augmented during the active period only in the cerebral cortex. This diurnal variation may play a role in the regulation of adenosine in relationship to sleep and wakefulness across the day. In contrast, we found no changes specifically with sleep deprivation in the activity of any enzyme in any brain region. Thus, changes in adenosine with sleep deprivation are not a consequence of alterations in adenosine enzyme activity.

5'-Nucleotidase↗
PubMed2003

Classification of Fourier transform infrared microscopic imaging data of human breast cells by cluster analysis and artificial neural networks.

Cluster analysis and artificial neural networks (ANNs) are applied to the automated assessment of disease state in Fourier transform infrared microscopic imaging measurements of normal and carcinomatous immortalized human breast cell lines. K-means clustering is used to implement an automated algorithm for the assignment of pixels in the image to cell and non-cell categories. Cell pixels are subsequently classified into carcinoma and normal categories through the use of a feed-forward ANN computed with the Broyden-Fletcher-Goldfarb-Shanno training algorithm. Inputs to the ANN consist of principal component scores computed from Fourier filtered absorbance data. A grid search optimization procedure is used to identify the optimal network architecture and filter frequency response. Data from three images corresponding to normal cells, carcinoma cells, and a mixture of normal and carcinoma cells are used to build and test the classification methodology. A successful classifier is developed through this work, although differences in the spectral backgrounds between the three images are observed to complicate the classification problem. The robustness of the final classifier is improved through the use of a rejection threshold procedure to prevent classification of outlying pixels.

Algorithms↗
PubMed2003

Should household contact examination in a low endemic situation of leprosy continue?

After more than 40 yrs of effort, leprosy is finally under control in Shandong province with only 50 to 70 new cases detected each year in the past 10 yrs. Contact examination is still compulsory and household contacts will be followed for 5 to 10 yrs, as directed by the guidelines of the national leprosy control program. In order to assess the value of contact examination in terms of case finding in a low endemic situation of leprosy in Shandong, we analyzed the data regarding all newly diagnosed leprosy cases in the past 11 yrs using the data abstracted from the national leprosy recording and reporting system, and a questionnaire-based survey to see how many incident leprosy cases would be detected if we followed the policy for contact examination of leprosy in Shandong. The results showed that 252 out of 547 leprosy cases diagnosed from 1990 to 2001 reported they had contact with different categories of primary leprosy cases. Among them, 90 cases had household primary leprosy cases. The mean incubation of the 252 index cases was 23 yrs. If we followed the national policy for contact tracing for 5 or 10 yrs, then only 12 (13.3%) and 10 (11.1%) of the 90 cases whose source of infection was household contacts would have been detected, respectively. Therefore, other approaches should be sought, in order to detect the few incident leprosy cases as early as possible in such a low endemic situation of leprosy in Shandong.

China↗
PubMed2003

Expression of endocrine gland-derived vascular endothelial growth factor in ovarian carcinoma.

The first tissue-specific angiogenic molecule, endocrine gland-derived vascular endothelial growth factor (EG-VEGF), was identified recently in human ovary, raising hopes of developing tumor type-specific angiogenesis inhibitors. In the present study, we analyzed the expression of EG-VEGF mRNA in normal human tissues and ovarian neoplasms by quantitative real-time reverse transcription-PCR. EG-VEGF mRNA was expressed in all ovarian neoplasms examined. No significant difference was identified among benign, low malignant potential neoplasms or stage I ovarian cancer, all of which exhibited 2-fold lower mRNA levels compared with normal premenopausal ovaries. EG-VEGF mRNA levels further decreased in late stage compared with early stage carcinomas (P < 0.05) and were consistently lower in laser capture microdissected tumor islets compared with surrounding stroma. EG-VEGF was undetectable by reverse transcription-PCR in 17 established epithelial ovarian cancer cell lines or in cultured human ovarian surface epithelial cells, whereas it was detected in peripheral blood as well as tumor-infiltrating T lymphocytes. Finally, in contrast to VEGF, EG-VEGF mRNA levels did not correlate with clinical outcome in advanced ovarian carcinoma. These results suggest that EG-VEGF is most likely derived from nonepithelial components of ovarian carcinomas and may play a marginal role in promoting angiogenesis in advanced ovarian carcinoma. We postulate that EG-VEGF-targeted antiangiogenic therapy may prove useful in early stage but not in advanced stage ovarian carcinoma.

Angiogenesis Inducing Agents↗
PubMed2003

[Expression of fetal epsilon and gamma globin gene in maternal peripheral blood].

OBJECTIVE: Traditional prenatal diagnosis for congenital diseases were villus sampling and amniocentesis. These invasive diagnosis methods are not only technical complicated, but also harmful to mother or fetus. Fetus in its different gestational age has its different type of hemoglobin or different amount of hemoglobin, especially epsilon hemoglobin exiting in the body of 10 weeks gestation fetal, however gamma hemoglobin has its high amount before baby to be born. But epsilon and gamma hemoglobin did not exist in the bodies of adults bodies. It is possible to use advanced molecular biological technique to extract the fetal hemoglobin gene from maternal peripheral blood. In articles from domestic and abroad, no report related to fetal hemoglobin extraction from maternal peripheral blood was found. We tried to use non-invasive method to detect fetal hemoglobin epsilon/gamma gene from maternal peripheral blood by molecular biological technique. The purpose was to establish a convenient, sensitive and special method to be a basis of screening prenatal diseases in the population and lay a basis for family planning and clinical application. METHODS: Blood samples were collected and the fetal mRNA extracted from the pregnant women with the use of random primer. We used ultraviolet spectrophotometer to test the concentration and purity of extracted mRNA are suitable for reverse transcription. Reverse transcription of mRNA into cDNA was carried out and cDNA by PCR with the special epsilon/gamma primer being used. Via 1.2% EB in agarose gel electrophoresis, we used "Gel Works System" to scan the electrophoresis image to detect epsilon/gamma gene band. RESULTS: The peripheral blood of pregnant women was collected. With RT-PCR and agarose gel electrophoresis method, we detected epsilon/gamma gene successfully in 7 samples with 6 positive and 1 negative. CONCLUSION: This was the first time that we used non-invasive way to detect expression of fetal epsilon/gamma gene in maternal blood to have found that this was a simple method to separate fetal cells from maternal blood, and could easily be accepted by pregnant women. Success of RT-PCR to detect fetal specific mRNA gave the hint that this method could be used in the field of prenatal diagnosis of hemoglobin disease, predicting fetal gender, predicting Rh blood type and single gene disease and be used widespread in prenatal diagnosis.

Female↗
PubMed2003

[Expression of nuclear factor-kappaB in bone marrow cells from patients with acute leukemia and its relationship with P21, MMP-2 and MMP-9].

To investigate the expression of NF-kappaB in acute leukemia and its relationship with P21, and matrix metalloproteinases (MMP), the expression of NF-kappaB, P21, MMP-2 and MMP-9 in bone marrow cells from patients with acute leukemia (AL) was detected using immunocytochemical technique. The results showed that the expression ratios of NF-kappaB, P21, MMP-2 and MMP-9 in untreated AL group were significantly higher than those in remission and normal control groups (P < 0.05), and no obvious difference was seen between remission and normal control groups. The expression of NF-kappaB was correlated with that of P21, MMP-2 and MMP-9 (r = 0.767, 0.729 and 0.803, respectively, P < 0.05). This study indicated that P21 protein, encoded by oncogene Ras, and NF-kappaB were super-expressed in leukemia cells. In conclusion, after activation by Ras, NF-kappaB combined with the kappaB sequences of MMP-2 and MMP-9 genes, then upregulated their expression. MMP might enhance the degradative function of leukemic cell, thus to make cells easier to cross through the bone marrow barrier and release into blood.

Acute Disease↗
PubMed2003

[Apoptosis of cancer cells induced by influenza virus and its elementary mechanism].

OBJECTIVE: To study the apotosis-inducing effects of influenza virus on cancer cells and the role of FasL. METHODS: Four strains of cancer cells (Hela, Raji, SMMC-7721 and SPC-A-1) were infected with 20 m. o. i influenza virus and the effects of apoptosis were detected at different time points post infection by electron microscopy, DNA agrose gel electrophoresis, PI stained flow cytometry, and Annexin-V FITC/PI stained flow cytometry. And the concentration of FasL in the culture supernatant was measured with the use of ELISA at the same time. RESULTS: All the four strains of cancer cells showed apoptotic morphological changes. DNA agarose electrophoresis also showed "ladder" in a time dependent manner after virus infection. During this course, there was an obvious increase of FasL concentration in the cell culture supernatant. CONCLUSION: Influenza virus can induce tumour cells apoptosis in vitro, and it is probably related to the increased expression of FasL.

Adenocarcinoma↗
PubMed2003

[A study on the protective efficacy of yisheng injection against IRI in pig renal-transplant model and the mechanism therein involved].

OBJECTIVE: To inquire into the mechanism of the protective efficacy of Yisheng injection against ischemia/reperfusion injury(IRI) in pig renal-transplant model. METHODS: A total of 24 Chinese Sichuan White Pigs (SWPs) (2-3 months old, 17.5 +/- 4.6 kg, with clear family background) were used. 6 pairs of SWPs with better results of tissue typing were allocated to the group of renal allotransplantation. The other SWPs were subjected to renal autotransplantation. Yisheng injection was added into the preservative fluid and injected intravenously after transplantation in the test groups against IRI. We detected the SWPs' liver and kidney functions and serum superoxide dismutase(SOD) and malondialdehyde(MDA) concentrations after transplantation. RESULTS: Serum creatinine and urea levels increased in 2 days after operation and then returned to normal in both groups except the pigs suffering from acute tubular necrosis or acute rejection. The concentrations of serum MDA, SOD began to increase 2 days after operation (P < 0.05). Less increase of serum MDA, less decrease of NO and more increase of SOD in test groups were detected, compared with those in control groups (P < 0.05). CONCLUSION: Yisheng injection has protective efficacy against IRI and hence may have an application foreground.

Animals↗
PubMed2003

[Surgical treatment of primary tracheal adenoid cystic carcinoma: report of 11 cases].

OBJECTIVE: To evaluate the clinical characteristics, diagnosis and treatment of primary tracheal adenoid cystic carcinoma. METHODS: The data of 11 patients with primary tracheal adenoid cystic carcinoma were reviewed. The age of the patients ranged from 30 to 49 years. The tumor situated at the upper trachea in 7 patients, including 2 invading the larynx and 1 invading the cricoid cartilage; at the middle trachea in 2, and at the lower trachea in 2. The surgical procedures included tracheal sleeve resection in 5 patients, with cricoid partial resection in 1; tracheal tumor curettement in 4; cervical trachea and larynx resection and tracheostomy in 2. RESULTS: All patients had an uneventful recovery. Stoma constriction occurred in 1 patients, and relapse in 1. There was no perioperative death. CONCLUSION: For patients with primary tracheal adenoid cystic carcinoma, early diagnosis and surgical treatment are recommended.

Adult↗
PubMed2003

[Sequence analysis and genetic polymorphisms of D4S1647 and D6S2414 loci in Chinese Han, Mongolian and Tibetan populations].

OBJECTIVE: To investigate the polymorphisms of two short tandem repeats (STR) loci D4S1647 and D6S2414 in Chinese Han, Mongolian and Tibetan populations. METHODS: Blood and saliva samples were collected from 308 unrelated individuals in the three populations. DNA was extracted by chelex-100 method and amplified by the polymerase chain reaction (PCR). The PCR products were analyzed by nondenaturing polyacrylamide gel electrophoresis and silver staining. RESULTS: The genotype distributions of D4S1647 and D6S2414 loci were in accordance with Hardy-Weinberg equilibrium. The frequencies of alleles showed no significant differences among the three populations. Analyses of Han families indicated that the alleles agreed with Mendelian inheritance law. CONCLUSION: This study yielded information on the genetic polymorphisms of the two STR loci in Chinese Han, Mongolian and Tibetan populations.

Alleles↗
PubMed2003

[A finite element analysis system for two-demension morphological analysis of the soft tissue in orthognathic surgery].

OBJECTIVE: To evaluate a finite element method (FEM) for analysis of the cranial-facial morphology. METHODS: The two-dimensional finite element analysis system was established and used to analysis the lateral side morphology of the soft tissue by the change of each finite unit of the soft tissue in a X-ray cranial-facial lateral cepholometrics film. RESULTS: The finite element analysis system was showing very well in the figures and data made by the system. CONCLUSION: Finite element analysis system may be a good supplement of the traditional X-ray cephalometrics to the soft tissue of orthognatics.

Cephalometry↗
PubMed2003

[Expression of recombinant human endostatin in Pichia pastoris and its inhibitory effects on the growth of human lungadenocarcinoma Astc-a-1 cells].

OBJECTIVE: To achieve expression of recombinant human endostatin (rhES) in a highly efficient foreign gene expression system, the yeast strain Pichia pastoris, and to evaluate the inhibitory effect of rhES on the growth of nude mouse pulmonary adenocarcinoma cells. METHODS AND RESULTS: The rhES gene was efficiently expressed in the yeast strain, and heparin affinity chromatography yielded highly purified endostatin identified by Western blotting, which proved to significantly inhibit the growth of the ECV-304 cells in vitro and also the growth of the lung adenocarcinoma Astc-a-1 in nude mice. CONCLUSIONS: The rhES gene can be expressed in Pichia pastoris, and has the ability to restrain the growth of ECV-304 cells and lung adenocarcinoma Astc-a-1 in nude mice, showing important potentials for future clinical applications.

Adenocarcinoma↗
PubMed2003

Apoptosis in Raji cell line induced by influenza A virus.

OBJECTIVE: To study the apoptotic effects of influenza A virus on the Raji cell line. METHODS: Cultured Raji cells were infected with influenza A virus at a multiplicity of infection (m.o.i) of 20 and the effects of apoptosis were detected at different time points post infection using the following methods: electron microscope, DNA agarose gel electrophoresis, PI stained flow cytometry (FCM) and Annexin-V FITC/PI stained FCM. RESULTS: Raji cells infected with influenza A virus showed changes of morphology apoptosis, DNA agarose electrophoresis also demonstrated a ladder-like pattern of DNA fragments in a time-dependent manner. PI stained FCM showed "apoptosis peak" and FITC/PI stained FCM showed apoptotic cells. Quantitative analysis indicated that the percentage of apoptotic Raji cells increased after infection, and cycloheximide (CHX), an eukaryotic transcription inhibitor, could effectively inhibit the apoptotic effects of influenza A virus in vitro. CONCLUSIONS: Influenza A virus can induce apoptosis in Raji cell line suggesting that it may lead to a potential method for tumor therapy.

Apoptosis↗
PubMed2003

Hepatitis gene chip in detecting HBV DNA, HCV RNA in serum and liver tissue samples of hepatitis patients.

OBJECTIVE: To study the preparation of diagnostic gene chip for detecting hepatitis B virus (HBV) and hepatitis C virus (HCV) and its accuracy in detecting HBV DNA and HCV RNA in serum and liver tissues. METHODS: The probes, which depend on the conservative gene fragment of hepatitis virus, was designed, synthesized and spotted on the modified glass. The probes and some other control probes were assembled on the diagnostic microarray of hepatitis virus. The gene of hepatitis virus, purified from blood or tissue, was labeled with fluorescence and hybridized to the microarray. The hybridized microarry was scanned with microarray scanner and the diagnostic result was analyzed from the scanning data. Fourty patients with hepatitis B virus and 40 healthy people or 40 patients with hepatitis C virus were subjected to detection of HBV DNA and HCV RNA with the hepatitis virus gene chip by the double-blind method. Paraffin liver specimens obtained from 99 cases of posthepatitic cirrhosis were used to detect HBV DNA. The liver tissues and serum from 15 cases of chronic hepatitis B were used to detect HBV DNA. Simultaneously, HBsAg and HBcAg were detected in the serum by fluorescence microparticle quantitation, HBV DNA and HCV RNA in the serum by PCR, and HBcAg in liver tissues by immunocytochemistry or HBV DNA by in situ molecular hybridization. RESULTS: Chip detection of serum specimens showed that 30 patients were HBV DNA positive and 10 HBV DNA negative in the 40 patients with HBV positive, 25 patients were HCV RNA positive and 15 patients were HCV RNA negative in the 40 patients with HCV positive, and all were HBV and HCV negative in the 40 healthy people. In 15 patients with HBV marker positive who were subjected to liver biopsy, 15 patients were detected HBV DNA positive in serum by gene chip, 15 patients HBcAg positive in liver tissues by immunocytochemistry, 14 patients HBV DNA positive in liver tissues by in situ molecular hybridization, and 14 patients HBV DNA positive in liver tissues by gene chip. Paraffin liver tissues specimens from the 99 patients with posthepatitis B cirrhosis showed that 67 patients were detected HBcAg positive by immunocytochemistry, 53 patients HBV DNA positive by in situ molecular hybridization, and 46 patients HBV DNA positive by gene chip. In the 46 patients, 40 patients were detected HBV DNA and HBcAg positive by in situ molecular hybridization and immunocytochemistry, 6 patients only HBcAg positive, and 33 patients HBcAg negative. CONCLUSIONS: The designed diagnostic gene chip can be used to simultaneously detect serum HBV DNA and HCV RNA, but the positive rate of HCV RNA diagnosed by this chip is lower. The gene chip can detect HBV DNA in serum and in liver tissue.

DNA, Viral↗