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Biomedical subjects

Lin Zhang

Publications and source records attributed to Lin Zhang.

At least 253 records · Page 14Linked to original sources
PubMed2004

[Expression of transforming growth factor-beta1 and c-fos and p27 in human middle ear cholesteatoma].

OBJECTIVES: To analyze the expression of transforming growth factor-beta1 (TGF-beta1), cyclin dependent kinase inhibitor (p27) and c-fos in human middle ear cholesteatomas and to investigate the correlation between their expression and the ability of erosion of cholesteatoma. METHODS: Immunohistochemical staining (SP method) of 31 cholesteatomas and 11 external ear canal skin samples from patients and 10 external ear canal skin samples from healthful men which were taken intraoperatively, was performed for c-fos, TGF-beta1 and p27 positivity. The signals representing the expression of c-fos, TGF-beta1 and p27 were observed under microscope and scanned into a computer by an image scanner. The gray-scale of positive signals were quantitated by image processing computer. RESULTS: The percentage of positive expression of TGF-beta1 and c-fos in cholesteatoma were 87.1% and 83.9%, respectively. Their expression tended to be increased greatly compared with which in the skins of the control groups. Positive p27 signals were not observed in cholesteatomas and external ear skin tissues. It showed statistically significant correlation between expression of c-fos and the ability of erosion of cholesteatoma. There was correlation between the express ion of TGF-beta1 and the ability of erosion of cholesteatoma too. But there was no correlation between the expression of c-fos and TGF-beta1. CONCLUSION: The expression of c-fos in cholesteatoma was significally higher compared with which in the skin of external auditory of cholesteatoma patients and healthful men, which indicate that c-fos plays an important role in the hyperproliferative of cholesteatoma. The expression of TGF-beta1 was significant higher in cholesteatoma, which indicate that cytokines such as TGF-beta1 play a great role in the etiology of cholesteatoma.

Adult↗
PubMed2004

[The expression of bFGF and its receptor FGFR1 in rat after fluid-percussive brain injury].

OBJECTIVE: Study on the pattern of changes of bFGF and FGFR1 immunoreactivity occurred in the experimental brain injury model for the purpose of providing the scientific basis for molecular pathological diagnosis, forensic identification, clinical treatment as well as further ascertaining the molecular mechanism of brain injury. METHODS: Male SD rats were divided into normal control, sham operation control and injury groups. The rats of injury groups were subjected to moderate lateral fluid percussion brain injury (0.2 mPa). The injury groups were then subdivided into 30 min, 1, 3, 6, 12 h, 1, 3, 7 d groups according to the time elapsed after injury. The SP immunohistochemistry method was used to examine the expression of both bFGF and FGFR1 factors in rat brain. RESULTS: In the brain of normal control and sham operation control groups, the low expression levels of bFGF and FGFR1 were observed. The increase of bFGF and FGFR1 immunoreactivity could be observed 6 h after injury in cortex and brain stem, reached to the peak at 1 d and remained at the high level up to 3 d, then partly declined at 7 d. In hippocampus, however, the increase occur as early as 3 h after injury, reached to the peak at 1 d and then decreased progressively, and returned to basal level at 7 d. CONCLUSION: The results suggested that brain injury induced the gene expressions of bFGF and FGFR1. The bFGF may contribute to maintenance of nerve cell survival and the repair of damaged neural tissues after CNS injury and the patterns of their level change were quite regular and can be used for timing of injury in forensic medicine aspect.

Animals↗
PubMed2004

[Overexpression of HER2/neu downregulates wild p53 protein expression via PI3K and Ras/Raf/MEK/ERK pathways in human breast cancer cells].

OBJECTIVE: To evaluate the effect of HER2/neu overexpression on wild p53 protein expression and to delineate the related signal pathways. METHODS: Lipofectin method was used to transfer HER2/neu into human breast tumor cell line MCF7. Overexpression of HER2/neu was then determined by Western blot. Western blot was also used to detect the quantity of p53, Akt, p-Akt, p-Raf, p-MEK, p-ERK protein. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect p53 mRNA expression. PI3K pathway inhibitor LY294002 and MEK inhibitor U0126 were used to block the two pathways. The subsequent effect on p53 protein expression was then determined. RESULTS: HER2/neu-overexpressed MCF7 clone (MCF7-neu3) was successfully established, in which the amount of HER2/neu protein was 13 times more than that in parental MCF7 cells. The amount of p53 protein in MCF7-neu3 was 40% of that in parental MCF7 cells (P < 0.01), while there was no difference on p53 mRNA level. There were 2.5, 2.0, 1.6 and 1.6 fold increase in the amount of p-Akt, p-Raf, p-MEK, p-ERK protein respectively in MCF7-neu3 to that in parental MCF7 cells (P < 0.01). When treated with LY294002 or U0126 for 24 hours, the amount of wild p53 protein in MCF7-neu3 cells was 1.7 or 1.5 times higher than those in DMSO treated cells. There were 4.7 or 5.3 times increase in the p53 protein when MCF7-neu3 cells were treated with LY294002 or U0126 for 48 hours (P < 0.01). Similar results were not seen in MDA-MB-453 cells which contained mutant p53. CONCLUSIONS: HER2/neu overexpression can activate PI3K and Ras/Raf/MEK/ERK pathways, resulting in reduction of wild p53 protein expression. This may be the molecular mechanism responsible for the poor prognosis and therapeutic non-responsiveness in HER2/neu-overexpressed breast cancer patients.

Breast Neoplasms↗
PubMed2004

[Clinical observation of ZD1839 in treating 32 cases of non-small-cell lung cancer].

OBJECTIVE: To study e the therapeutic and adverse effects of ZD1839 in treating non-small-cell lung cancer (NSCLC). METHODS: The therapeutic and adverse effects of ZD1839 given orally were observed in 32 NSCLC cases after a treatment course more than 90 d. RESULTS: The rates of complete remission (CR), partial remission (PR), and stabilization (SD) were 0%, 18.75%, and 37.50% respectively, with a disease control rate of 56.25%. The adverse effects of this agent included acneiform rash, diarrhea, aminotransferase elevation, nausea and vomiting, occurring in 31.25%, 18.75%, 12.50% and 15.63% of the cases respectively. No interstitial lung disease was found. CONCLUSION: ZD1839 is a new drug producing acceptable disease control rate along with tolerable adverse effects in patients with lung cancer.

Aged↗
PubMed2004

[Influence of intestinal dysbacteriosis on immune and hematopoietec function in mice].

OBJECTIVE: To study the effects of intestinal microflora alteration on specific and nonspecific immune function and hematopoietic function of mice. METHODS: Sixty BALB/C mice were divided at random into two groups, experimental group and control group, with 30 mice in each. The mice in the experimental group were given kanamycin 50 mg while those in the control group were given distilled water intragastrically everyday for consecutive 10 days. After the 10 day treatment all the mice were sacrificed, and the cecal contents were collected for quantitative analysis of the intestinal bacterial flora. Certain indexes of immune function, including phagocytosis rate of macrophages, number of T lymphocytes positively stained by esterase and serum interleukin 2 (IL-2) content, and the weight of the spleen, granulocyte-macrophage colony stimulating factor etc. as indexes of hematopoietic function were determined. RESULTS: In the group, the quantity of Enterobacteriaceae, Enterococcus, Bifidobacterium and Lactobacillus were significantly lower than that in the control group (P < 0.01). The number of PFC (plaque forming cells), the phagocytosis rate of macrophage, the number of T lymphocytes with positive NANE staining, the level of IL-2 significantly decreased when compared with that in the control group (P < 0.01). The weight of the spleen in the experimental group decreased when compared with that in the control group (P < 0.01). Levels of IL-3, GM-CSF, the total number of WBC and the proportion of neutrophil remarkably decreased as compared to that in the control group (P < 0.01). Analysis of the correlations between normal microflora, immunologic and hematopoietic indexes showed that marked positive correlations between the quantity of Bifidobacteria and each immune index including the levels of IL-3 and GM-CSF. There was a positive correlation between IL-2 and IL-3, IL-2 and GM-CSF as well. CONCLUSION: The application of antibiotics may cause changes in the structure and quantity of intestinal microflora. The dysbacteriosis may decrease the immune function of organism. The dysbacteriosis may decrease the hemopoietic function. The dysbacteriosis, the decrease in immune and hematopoietic function may affect one another. The balance in microecosystem should be emphasized and antibiotics should be applied rationally to reduce the side effects such as dysbacteriosis.

Animals↗
PubMed2004

[Construction and prokaryotic expression of a recombinant immunotoxin fused with mouse interleukin 18 and truncated Pseudomonas exotoxin].

OBJECTIVE: To construct a new recombinant immunotoxin expression vector by fusion of mouse interleukin 18 (mIL-18) gene and a truncated form of A (PE38) gene, and examine the expression of IL-18-PE38 fusion protein in Escherichia coli. METHODS: mIL-18 cDNA was cloned from mouse liver tissue through reverse transcription-polymerase chain reaction (RT-PCR). The mIL-18 cDNA was subcloned into a PE38 gene inserted fusion protein expression plasmid. The recombinant vector was identified by restriction endonucleases digestion, PCR and DNA sequencing. After transformed into E. coli BL21 and induced by IPTG, the expressed product was obtained and detected the molecular weight and specificity by SDS-PAGE and Western-blotting. RESULTS: The new recombinant immunotoxin expression vector was constructed successfully. The IL-18-PE38 fusion protein was expressed in E. coli BL21, and the molecular weight of the expression product was identical to the expected value. In addition, the protein expressed could react with the specific antibody against mIL-18. CONCLUSION: IL-18-PE38 recombinant immunotoxin expression vector will provide the basis for study on the targeted cytotoxic activity to Th1 cell and may have some potential value in the treatment of autoimmune disease and T cell leukemias.

Animals↗
PubMed2004

[Comparison of hepatic protein synthesis function between Banna Minipig Inbred Line and human].

OBJECTIVE: This is a research aimed at comparing the hepatic protein synthesis function of Banna Minipig Inbred Line (BMI) with that of human so as to evaluate the possibility of porcine liver replacement of human counterpart. METHODS: The venous blood samples from BMI and volunteer participants were collected. The albumin and total protein in the separated sera were tested using Beckman delta CX7 autoanalyzer, and serum protein electrophoresis was performed. RESULTS: No significant differences in albumin and in the percentage and concentration of globulins synthesized in liver (alpha1-, alpha2- and beta-globulin) between BMI and human were observed. The percentage and concentration of gamma-globulin synthesized in the lymphocytes of BMI were significantly higher than those of human. CONCLUSION: The above findings suggested the similarity between BMI liver and human liver in respect to albumin and alpha, beta-globulin synthesis.

Alpha-Globulins↗
PubMed2004

[Study on association between aldosterone synthase gene polymorphism and the left ventricular structure and function of patients with dilated cardiomyopathy in China].

OBJECTIVE: To investigate the association between a -344 C/T polymorphism of aldosterone synthase gene (CYP11B2) and the left ventricular structure and function of patients with dilated cardiomyopathy (DCM) in China. METHODS: Eighty-nine patients with DCM were genotyped by PCR-RFLP, and were divided into TT, TC, CC and TT+CC four groups by their genotypes, respectively. Left ventricular structure and function were assessed with echocardiography. RESULTS: There was no significant difference between four groups in left ventricular diameters, mass and ejection fraction in patients with DCM. CONCLUSION: The data were not in favor of a significant association between the aldosterone synthase gene CYP11B2 and the left ventricular structure and function in patients with DCM.

Adult↗
PubMed2004

Assessment of knowledge and skills in early diagnosis of leprosy and attitudes towards leprosy amongst doctors working in dermatological services, Shandong Province, People's Republic of China.

After the leprosy control programme in Shandong Province, China, had declared elimination in 1994, it was no longer cost effective to rely on rapid surveys, population surveys and contact tracing for case detection, and since then most new cases have been diagnosed by the dermatological services. The dermatological services will continue to play an important role in diagnosis of the few incident leprosy cases scattered in wide geographic areas and in a population of 90 million. In order to better understand the knowledge and skills in early diagnosis of leprosy among doctors working in dermatological services around the province, doctors attending the dermatological annual meeting and a dermatological training workshop were assessed on their knowledge and skills in early diagnosis of leprosy and their attitude towards leprosy with a semi-structured questionnaire. The results showed that continuous training was needed for dermatologists from both general hospitals and the leprosy control programme. In particular, the training methods for the skills in nerve examination including palpation of peripheral nerves and nerve function assessment should be improved.

Adult↗
PubMed2004

[Biomass and net primary productivity of secondary evergreen broadleaved forest in Huangmian Forest Farm, Guangxi].

By the methods of sampling plot harvesting method and allometric dimension analysis, we measured the belowground and aboveground standing biomass and net primary productivity (NPP) of the secondary evergreen broadleaved forest in Huangmian Forest farm of Guangxi, southern China, with the location of 24 degrees 51'N and 109 degrees 51'E and an altitude of about 315 m. The total biomass was 99.96 t x hm(-2), aboveground and belowground biomasses accounted for 69.41% and 30.59%, respectively. The leaf area index of trees and undergrowth shrubs was 6.50, and the total annual NPP was 24.65 t x hm(-2) x yr(-1) by estimate, aboveground and belowground NPP accounted for 44.54% and 55.46%, respectively. The NPP of fine roots was 11.79 t x hm(-2) x yr(-1), being 86.24% of the belowground NPP.

Biomass↗
PubMed2004

[Micellar electrokinetic capillary chromatographic separation of amino acids derivatized with 2-(9-carbazole)-ethyl chloroformate as a pre-column labeling reagent].

2-(9-Carbazole)-ethyl chloroformate (CEOC) has been used for the pre-column derivatization of amino acids in micellar electrokinetic capillary chromatography (MEKC). Nine amino acid standards (Ser, Thr, Gly, Glu, Asp, Val, Ile, Leu, Phe) were labeled with CEOC and separated in a buffer system containing 20 mmol/L borate-30 mmol/L sodium lauryl sulfate (SDS) and 3% acetonitrile at pH 9.0 with an applied voltage of 18 kV and column temperature of 25 degrees C. The derivatives were detected at UV 214 nm. Under optimal conditions, this method offers a baseline separation for nine CEOC-derivatized amino acids within 14 min. The linearity range was from 0.025 to 0.25 mmol/L and the detection limits were from 2.15 to 2.46 micromol/L.

Amino Acids↗
PubMed2004

[Expression of VEGF-C and VEGFR-3 in human laryngeal squamous cell carcinomas and cervical metastatic lymph node tissues].

OBJECTIVE: To study the gene expression of vascular endothelial growth factor C (VEGF-C) and vascular endothelial growth factor receptor-3 (VEGFR-3) in laryngeal squamous carcinoma and their relation with clinic pathologic features. METHOD: VEGF-C and VEGFR-3 gene expression in 30 cases of normal laryngeal mucosa tissue (NLM), primary laryngeal carcinoma (PLC) and cervical lymph node (CLN) were examined by reverse transcription polymerase chain reaction (RT-PCR). RESULT: The gene expression of VEGF-C and VEGFR-3 are different among normal laryngeal mucosa tissue, primary laryngeal carcinoma and cervical lymph node in the same patient. In primary laryngeal carcinoma, expression of VEGF-C, VEGFR-3 were significantly higher in lymph node positive group than in lymph node negative group and associated with histological grade of differentiation; The gene expression of VEGF-C, VEGFR-3 were not associated with age, sex, site, T stage. CONCLUSION: VEGF-C, VEGFR-3 have prognostic significance in laryngeal carcinoma.

Aged↗
PubMed2003

MEK kinase 1 regulates c-Jun phosphorylation in the control of corneal morphogenesis.

PURPOSE: To study the in vivo role of MEK kinase 1 (MEKK1) in corneal development. METHODS: Wild type and Mekk1DeltaKD/DeltaKD mice eye tissues were examined by staining with hematoxylin and eosin for morphogenesis and Masson's trichrome for extracellular matrix (ECM) deposition. The cells expressing ECM gene transcripts of Collagen I, Keratocan, and Lumican in corneal stroma were identified by in situ hybridization and the level of Collagen I mRNA in the developing cornea was quantified by real-time RT-PCR. Immunohistochemistry staining was employed to study the expression and N-terminal phosphorylation of c-Jun and the expression of epithelium differentiation markers and intercellular structural proteins of the corneal epithelium. RESULTS: Mekk1DeltaKD/DeltaKD mice exhibited the "eye open at birth" phenotype (EOB), and developed eye defects and severe pathology secondary to impaired eyelid formation. The corneal stroma of Mekk1DeltaKD/DeltaKD fetuses, although exhibiting normal morphology, thickness, and keratocyte proliferation, showed reduced extracellular matrix (ECM) accumulation, corresponding to a decrease in transcription of Lumican, Keratocan, and Collagen I. Immunohistochemistry studies demonstrated that MEKK1 ablation caused a remarkable reduction in the expression of occludin and zonula occluden protein-1 (ZO-1), components of tight junction, but had no effect on the expression of E-cadherin and beta-catenin for adherens junctions, desmoplakin and desmoglein for desmosomes and cytokeratins 12 and 14 for cornea-type epithelial differentiation in the developing cornea. c-Jun was abundantly expressed in the developing corneal epithelium and its phosphorylation was considerably reduced in Mekk1DeltaKD/DeltaKD fetuses. CONCLUSIONS: In addition to its role in eyelid morphogenesis, MEKK1 is crucial for corneal development such that its ablation caused a reduction of ECM deposition in corneal stroma and disturbance of tight junctions in corneal epithelium. c-Jun phosphorylation in corneal epithelium is a downstream event of the MEKK1 pathway, likely contributing to corneal development and function. Altogether, MEKK1 plays a major role in ocular surface morphogenesis and its ablation leads to damage and various eye manifestations at postnatal stages.

Animals↗
PubMed2003

Multivariate calibration standardization across instruments for the determination of glucose by Fourier transform near-infrared spectrometry.

The transfer of multivariate calibration models is investigated between a primary (A) and two secondary Fourier transform near-infrared (near-IR) spectrometers (B, C). The application studied in this work is the use of bands in the near-IR combination region of 5000-4000 cm(-)(1) to determine physiological levels of glucose in a buffered aqueous matrix containing varying levels of alanine, ascorbate, lactate, triacetin, and urea. The three spectrometers are used to measure 80 samples produced through a randomized experimental design that minimizes correlations between the component concentrations and between the concentrations of glucose and water. Direct standardization (DS), piecewise direct standardization (PDS), and guided model reoptimization (GMR) are evaluated for use in transferring partial least-squares calibration models developed with the spectra of 64 samples from the primary instrument to the prediction of glucose concentrations in 16 prediction samples measured with each secondary spectrometer. The three algorithms are evaluated as a function of the number of standardization samples used in transferring the calibration models. Performance criteria for judging the success of the calibration transfer are established as the standard error of prediction (SEP) for internal calibration models built with the spectra of the 64 calibration samples collected with each secondary spectrometer. These SEP values are 1.51 and 1.14 mM for spectrometers B and C, respectively. When calibration standardization is applied, the GMR algorithm is observed to outperform DS and PDS. With spectrometer C, the calibration transfer is highly successful, producing an SEP value of 1.07 mM. However, an SEP of 2.96 mM indicates unsuccessful calibration standardization with spectrometer B. This failure is attributed to differences in the variance structure of the spectra collected with spectrometers A and B. Diagnostic procedures are presented for use with the GMR algorithm that forecasts the successful calibration transfer with spectrometer C and the unsatisfactory results with spectrometer B.

Algorithms↗
PubMed2003

The predicted TM10 transmembrane sequence of the cardiac Ca2+ release channel (ryanodine receptor) is crucial for channel activation and gating.

The predicted TM10 transmembrane sequence, (4844)IIFDITFFFFVIVILLAIIQGLII(4867), has been proposed to be the pore inner helix of the ryanodine receptor (RyR) and to play a crucial role in channel activation and gating, as with the inner helix of bacterial potassium channels. However, experimental evidence for the involvement of the TM10 sequence in RyR channel activation and gating is lacking. In the present study, we have systematically investigated the effects of mutations of each residue within the 24-amino acid TM10 sequence of the mouse cardiac ryanodine receptor (RyR2) on channel activation by caffeine and Ca(2+). Intracellular Ca(2+) release measurements in human embryonic kidney 293 cells expressing the RyR2 wild type and TM10 mutants revealed that several mutations in the TM10 sequence either abolished caffeine response or markedly reduced the sensitivity of the RyR2 channel to activation by caffeine. By assessing the Ca(2+) dependence of [(3)H]ryanodine binding to RyR2 wild type and TM10 mutants we also found that mutations in the TM10 sequence altered the sensitivity of the channel to activation by Ca(2+) and enhanced the basal activity of [(3)H]ryanodine binding. Furthermore, single I4862A mutant channels exhibited considerable channel openings and altered gating at very low concentrations of Ca(2+). Our data indicate that the TM10 sequence constitutes an essential determinant for channel activation and gating, in keeping with the proposed role of TM10 as an inner helix of RyR. Our results also shed insight into the orientation of the TM10 helix within the RyR channel pore.

Amino Acid Sequence↗
PubMed2003

Residue Gln4863 within a predicted transmembrane sequence of the Ca2+ release channel (ryanodine receptor) is critical for ryanodine interaction.

Despite the pivotal role of ryanodine in ryanodine receptor (RyR) research, the molecular basis of ryanodine-RyR interaction remains largely undefined. We investigated the role of the proposed transmembrane helix TM10 in ryanodine interaction and channel function. Each amino acid residue within the TM10 sequence, 4844IIFDITFFFFVIVILLAIIQGLII4867, of the mouse RyR2 was mutated to either alanine or glycine. Mutants were expressed in human embryonic kidney 293 cells, and their properties were assessed. Mutations D4847A, F4850A, F4851A, L4858A, L4859A, and I4866A severely curtailed the release of intracellular Ca2+ in human embryonic kidney 293 cells in response to extracellular caffeine and diminished [3H]ryanodine binding to cell lysates. Mutations F4846A, T4849A, I4855A, V4856A, and Q4863A eliminated or markedly reduced [3H]ryanodine binding, but cells expressing these mutants responded to extracellular caffeine by releasing stored Ca2+. Interestingly these two groups of mutants, each with similar properties, are largely located on opposite sides of the predicted TM10 helix. Single channel analyses revealed that mutation Q4863A dramatically altered the kinetics and apparent affinity of ryanodine interaction with single RyR2 channels and abolished the effect of ryanodol, an analogue of ryanodine, whereas the single channel conductance of the Q4863A mutant and its responses to caffeine, ATP, and Mg2+ were comparable to those of the wild type channels. Furthermore the effect of ryanodine on single Q4863A mutant channels was influenced by the transmembrane holding potential. Together these results suggest that the TM10 sequence and in particular the Q4863 residue constitute an important determinant of ryanodine interaction.

Amino Acid Sequence↗