Biomedical subjects

S Jin

Publications and source records attributed to S Jin.

At least 127 records · Page 7Linked to original sources

PubMed1999

Functionalized copolymers and their composites with polylactide and hydroxyapatite.

Synthetic copolymers poly(epsilon-caprolactone-co-vinylphosphonic acid) (P(MDOVPA) and poly(epsilon-caprolactone-co-dimethylvinylphosphoester) (P(MDOVPE)) were used to prepare composites with polylactide (PLac) and hydroxyapatite (HAp). The P(MDOVPA) is used as filler in PLac films, as it has pendant functional groups P(O)(OH)2, providing nucleation sites for the deposition of HAp in simulated body fluid. HAp growth on P(MDOVPA) powder and PLac-P(MDOVPA) film was observed by Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). P(MDOVPE) and PLac blend are miscible, and the incorporation of hydrophilic P(MDOVPA) into PLac increased the hydrophilicity of the blend. Synthetic HAp was used to make multilayered, alternating organic-inorganic composites with porous PLac-P(MDOVPE) blends.

Journal Article↗

PubMed1999

Endomorphin-1 reduces carrageenan-induced fos expression in the rat spinal dorsal horn.

Intraplantar injection of carrageenan induced significant Fos expression in the superficial and deep spinal dorsal horn at the L(4)-L(5)segments and extensive peripheral edema of the ipsilateral foot in rats. Intraplantar injection of endomorphin-1, endogenous ligand for mu opioid receptor, in the same region produced dose-dependent reduction of carrageenan-induced Fos expression and peripheral edema, which were completely blocked by co-administration of intraplantar injection of naloxone (20 microgram). The systemic injection of the highest dose of endomorphin-1 (50 microgram) had no significant reductory effect on Fos expression and peripheral edema. These results further provided a strong evidence for involvement of mu opioid receptor in peripheral analgesia, particularly in inflammation pain.

Analgesics, Opioid↗

PubMed1999

Early postmolt performance of laying hens fed a low-protein corn molt diet supplemented with corn gluten meal, feather meal, methionine, and lysine.

Commercial White Leghorn hens (65, 63, or 70 wk of age in Experiments 1, 2, and 3, respectively) were induced molted by feed withdrawal until approximately 28% body weight was lost. All hens were then weighed, and seven replicate groups of 12 hens each were fed molt diets. In Experiment 1, three diets consisted of a corn basal diet (7.9% CP) or this diet supplemented with corn gluten meal (CGM) and Lys or feather meal (FM), Met, and Lys. In Experiments 2 and 3, varying levels of FM and FM with Met and Lys were evaluated. A 16% CP corn-soybean meal diet was used as a positive control in all experiments. The molt diets were fed for 17, 15, and 17 d in Experiments 1, 2, and 3, respectively, and production performance was measured for 8 wk from the beginning of feeding the layer diet. In all experiments, hens fed the 16% CP corn-soybean meal molt diet returned to egg production and regained body weight at a faster rate than did hens fed any of the other diets. In Experiment 1, early egg production of hens fed the corn basal diet supplemented with CGM and Lys or supplementation with FM, Met, and Lys was greater (P < 0.05) than that of hens fed the basal diet alone. In Experiment 2, very early egg production (Week 1) and body weight gain were lower (P < 0.05) for hens fed the corn basal diet than for hens fed the basal supplemented with FM, Met, and Lys. The addition of 5.75 or 8.5% FM or 5.75% FM plus Met and Lys generally increased (P < 0.05) early egg production and postmolt body weight gain compared to the corn basal diet in Experiment 3. The present study thus indicated that improved early postmolt performance may be achieved by supplementation of a low-protein corn molt diet with various combinations of CGM, FM, Met, and Lys.

Animal Feed↗

PubMed1999

Expression of the soxR gene of Pseudomonas aeruginosa is inducible during infection of burn wounds in mice and is required to cause efficient bacteremia.

Burn wounds are prone to infection by Pseudomonas aeruginosa, which is an opportunistic pathogen causing various human diseases. During infection, the bacterium senses environmental changes and regulates the expression of genes appropriate for survival. A purine-auxotrophic mutant of P. aeruginosa was unable to replicate efficiently on burn wounds, suggesting that burn wounds are purine-deficient environments. An in vivo expression technology based on purEK gene expression was applied to the burned mouse infection model to isolate P. aeruginosa genes that are specifically induced during infection. Four such in vivo-inducible (ivi) genetic loci were identified, including the gene for a superoxide response regulator (soxR), the gene for a malate synthase G homologue (glcG), an antisense transcript of a putative regulator responding to copper (copR), and an uncharacterized genetic locus. SoxR of Escherichia coli is known to regulate genes involved in protecting the bacterium against oxidative stress. The expression of soxR was proven to be highly inducible during the infection of burned mice and also inducible by treatment with paraquat, which is a redox-cycling reagent generating intracellular superoxide. The SoxR protein functions as an autorepressor in the absence of paraquat, whereas in the presence of paraquat, this autorepression is diminished. Furthermore, a soxR null mutant was shown to be much more sensitive than wild-type P. aeruginosa to macrophage-mediated killing. In support of this observation, a soxR null mutant exhibited a significant delay in causing systemic infections in the burned mice. Since most mortality in burn patients is caused by systemic infection, the defect in the ability to cause efficient bacteremia in burned mice suggests an important role of the soxR gene in the infection of burn wounds.

Amino Acid Sequence↗

PubMed1999

Immortalization of chinchilla middle ear epithelial cells by adenovirus 12-simian virus 40 hybrid virus.

In order to study the cellular and molecular mechanisms of the pathogenesis of otitis media, a chinchilla middle ear epithelial cell line (CMEE-1) with differentiated cell characteristics was established by infection of a primary culture with the adenovirus 12-simian virus 40 (Ad12-SV40) hybrid. This cell line has been in continuous culture for 42 passages, whereas the parent cells underwent senescence and died at the 8th passage. The cell line also retains epithelial morphology and expresses cytokeratin polypeptides 4, 7, and 18, characteristic markers for epithelia. In Western blots of cell proteins, bands at 94 and 53 kd were labeled after binding antibodies against SV40 large T antigen and p53, respectively. Karyotype analysis showed that the cell line is derived from chinchilla epithelial cells. These findings confirm that the cell line is a chinchilla epithelial cell immortalized by the hybrid virus.

Adenoviridae↗

PubMed1999

[Expression of focal adhesion kinase in lymphatic endothelial cells of metastasis].

This study was directed at the expression of focal adhesion kinase (pp125FAK) which is located together with vinculin and talin in the spot of cellular adhesion. The authors' intention was to collect reliable data on this important kinase in the signal pathways so as to provide in-depth materials for exploring the mechanism of tumor metastasis to lymphatic vessels. The immunohistochemical method was used to study the expression of FAK in lymphatic endothelial cells of metastaltci adenocarcinoma of rectum and its adjacent lymph-nodes. The result demonstrated that lymphatic endothelial cells expressed pp125FAK when lymphatic vessels were invaded by cancer cells. Reaction production was located in the cytoplasm. This study provides that there was a strong correlation between the expression of FAK in lymphatic endothelial cells and the metastasis of cancer to lymphatic vessels.

Adenocarcinoma↗

PubMed1999

The spreading of six comprehensive medical books of the Ming dynasty to Japan and their influence.

Plenty of medical books were spread to Japan from China in the Ming dynasty. The most influential ones include the six comprehensive books, viz, "Yi Shu Da Quan", "Yu Ji Wei Yi", "Yi Xue Zheng Chuan", "Yi Xue Men", "Wan Bing Hui Chun" and "Nan Bei Jing Yan Yi Fang Da Quan", all spread quite fast. To begin with, they promoted the reprinting of Chinese medical books in Japan in large amount since the 16th century, providing convenient textbooks for Japanese medical teaching. Finally, they help to develop the scholastic thought of "Dao San" in theory and practice. As a result, they also helped to rejuvenate Japanese medicine.

China↗

PubMed1999

[p16 gene suppresses growth of human esophageal carcinoma cells].

OBJECTIVE: To explore the effect of p16 gene on the growth inhibition of esophageal carcinoma cell line NEC. METHODS: The full length of wild-type p16 cDNA was transfected into the esophageal carcinoma cell line of human fetus induced by N-methyl-N-benzylnitrosamine (NMBzA). In these esophageal carcinoma cell, p16 gene was homozygously deleted. RESULTS: Expression of exogenous p16 gene in NEC cells was identified by dot blot and Western blot analyses. The growth rate of NEC transfected with p16 gene (NEC-p16) was markedly suppressed. Colony formation in soft agar was also decreased significantly. Cell cycle analysis by flow cytometry showed that the number of cells in G1-G0 phase of NEC-p16 cells was significantly increased while cells in S and G2 + M phase was decreased compared to that of the control NEC cells. CONCLUSION: Transduction of wild type p16 gene into p16 gene-depleted esophageal cancer cells can restore its suppressive effect on cell growth by arrest of cell cycle at G1 phase.

Esophageal Neoplasms↗

PubMed1999

[The relationship of lung function and heart function of RHD patients in different period].

OBJECTIVE: To investigate the relationship of heart function and lung function in RHD patients. METHODS: We compared heart posterior-anterior film, lung function test results, PaO(2) and O(2) Sat of blood gas analysis before and after motion before operation, early postoperation, late postoperation, according to heart function and cardiothoracic ratio in 98 RHD patients. RESULTS: With worsening of heart function and enlargement of cardiothoracic ratio, lung function worsened too. PaO(2) and O(2) Sat did not change apparently. The lung function of early postoperation did not improve significantly. The lung function improved gradually with better heart function and shortening of heart in later postoperation. But small air way obstruction and diffuse function and function residue volume changed slowly. CONCLUSIONS: Heart function affects the lung function directly. They were positively correlated.

Adolescent↗

PubMed1999

[Significance of telomerase activity detection by fine-needle aspiration in patients with breast cancer].

OBJECTIVE: To study the telomerase activity in samples of breast fine-needle-aspiration specimens and to investigate its potential clinical implications. METHODS: Ninety nine fine-needle aspiration specimens from 83 patients with breast cancers, 12 with benign lesions and 4 with breast inflammation, were studied for the presence of telomerase activity by a PCR-based telomere repeat amplification protocol (PCR-TRAP). RESULTS: Among 83 fine-needle aspiration specimens from patients with breast cancer, telomerase activity was detected in 61 of 69 cytologic-positive specimens, 5 of 7 cytologic-suspicious specimens and 4 of 7 cytologic-negative specimens. Sensitivity of telomerase activity detection was 84.3% (70/83); the coincidence rate between telomerase detection and cytologic confirmation was 77.1% (64/83). Of 12 specimens from patients with benign breast lesions, 4 were positive for telomerase activity, but 4 specimens from patients with breast inflammation were all negative. The Combined use of cytological and telomerase detection can improve the detection rates from 83.1% (69/83) to 93.9% (78/83). CONCLUSION: Detection of telomerase in breast tissue samples by fine-needle aspiration is a sensitive and specific method, which implies that it would be helpful in preoperative cytological diagnosis of breast cancer.

Biopsy, Needle↗

PubMed1999

[Effects of Rg1 on calcium channel of guinea pig ventricular myocytes].

OBJECTIVE: To evaluate the effect of Rg1 (purified saponin of Panax notoginseng) on L-Ca2+ channel of guinea pig ventricular myocytes. METHOD: The whole-cell patch clamp recording technique. RESULT: When the holding potential was kept at -40 mV, and the cell was depolarized to +40 mV for 150 ms at a frequency of 0.5 Hz.Rg1 10 mumol.L-1 and 30 mumol.L-1 could not reduce Bay K 8644 and nifedipine-sensitive L-type Ca2+ inward current (P > 0.05, n = 5). CONCLUSION: Rg1 should not be a Ca2+ channel antagonist.

Animals↗

PubMed1999

[Observation of curative effect of radical mastoidectomy with rebuilding back wall of external and defect tympanoplasty].

OBJECTIVE: To manage the back wall defect of external acoustic canal and opened mastoid cavity which was remained from radical mastoidectomy. METHOD: 31 ears with cholesteatomatous otitis media and 3 ears with skeletal ulcer were treated by primary operation which consisted of radical mastoidectomy with rebuilding back wall of external canal and tympanoplasty. RESULT: All cases were followed up for 5 years. And all of external anditory canal are normal in appearance. Sixteen ears reached auditory level for social interaction and another 16 for functional audition. CONCLUSION: The Primary operation that we mentioned above may resolve some problems such as mastoid cavity or big external canal which were remained from radical mastoidectomy. It is effective to improve hearing.

Adolescent↗

PubMed1999

[Clinical significance of detecting telomerase activity in ascites cells from patients with ovarian carcinoma].

OBJECTIVE: The purpose was to investigate the clinical significance of telomerase activity for tumor diagnosis in ascites cells from patients with ovarian carcinoma. METHODS: Thirty ascites specimens from patients with ovarian tumor were examined for telomerase activity by PCR-based TRAP (telomeric repeat amplification protocol) method, and the result of detection was compared with the cytological diagnosis. RESULTS: Telomerase activity was detected in ascites cells from patients with ovarian tumor in 19 of the 20 cytologic-possitive specimens and in 3 of the 7 cytologic-negative specimens and in all the 3 cytologic-suspicious specimens. The positive rate in 30 ascites samples by cytological examination and by the detection of telomerase activity was 66.67% (20/30), and 83.33% (25/30), respectively. CONCLUSIONS: The result suggested that measuring telomerase activity in ascites cells would be helpful to cytological examination in diagnosis of patients with ovarian carcinoma.

Ascites↗

PubMed1998

Low-field electron emission from undoped nanostructured diamond

Strong and sustained electron emission at low electric fields was observed in undoped, nanostructured diamond. Electron emission of 10 milliamperes per square centimeter was observed at applied fields of 3 to 5 volts per micrometer. These are the lowest fields ever reported for any field-emitting material at technologically useful current densities. The emitter consists of a layer of nanometer-size diamond particulates, which is heat-treated in a hydrogen plasma. These emission characteristics are attributed to the particles' high defect density and the low electron affinity of the diamond surface. Such emitters are technologically useful, because they can be easily and economically fabricated on large substrates.

Journal Article↗

PubMed1998

Regulation of DNA-dependent protein kinase by the Lyn tyrosine kinase.

The Src-like protein-tyrosine kinase Lyn is activated by ionizing radiation and certain other DNA-damaging agents, whereas the DNA-dependent protein kinase (DNA-PK), consisting of the catalytic subunits (DNA-PKcs) and Ku DNA-binding components, requires DNA double-stranded breaks for activation. Here we demonstrate that Lyn associates constitutively with DNA-PKcs. The SH3 domain of Lyn interacts directly with DNA-PKcs near a leucine zipper homology domain. We also show that Lyn phosphorylates DNA-PKcs but not Ku in vitro. The interaction between Lyn and DNA-PKcs inhibits DNA-PKcs activity and the ability of DNA-PKcs to form a complex with Ku/DNA. These results support the hypothesis that there are functional interactions between Lyn and DNA-PKcs in the response to DNA damage.

DNA-Activated Protein Kinase↗

PubMed1998

[The impact of maternal education on the dietary and nutritional status of preschool children--a case study in 8 provinces of China].

This analysis is based on the data from China Health and Nutrition Survey in collaboration with University of North Carolina at Chapel Hill undertaken in 8 provinces of China from 1993 to 1996. Totally, 1098 mother-child pairs under age 6 were investigated. Descriptive analysis and stratified analysis are applied to investigate the impact of maternal education on the dietary and nutritional status of children. Both the crude analysis and after controlling for confounding variables, maternal education in the population remains statistically relevant to children's dietary and nutritional status. The proportion of low body weight and stunting children is the highest in the group with maternal education level being below preliminary school, the lowest in the group with education level being above high middle school. Moreover, in these three groups, the higher the level of maternal education, the greater the percentage of nutrients intake of China RDA, especially those from animal food. These results fully illustrate the importance of maternal education for the prevention of malnutrition in children.

Adult↗

PubMed1998

Loss of beta1 integrin function results in a retardation of myogenic, but an acceleration of neuronal, differentiation of embryonic stem cells in vitro.

Integrin cell surface receptors play an important role for cell adhesion, migration, and differentiation during embryonic development by mediating cell-cell and cell-matrix interactions. Less is known about the function of integrins during commitment and lineage determination of early embryogenesis. Homozygous inactivation of the beta1 integrin gene results in embryonal death in mice around the time of implantation. In vitro, differentiation of embryonic stem (ES) cells which lack beta1 integrin (beta1-/-) into the cardiogenic lineage is delayed and results in a disordered cellular specification (Fässler et al., J. Cell Sci. 109, 2989-2999, 1996). To analyze beta1 integrin function during myogenesis and neurogenesis we studied differentiation of beta1-/- ES cells via embryoid bodies into skeletal muscle and neuronal cells in vitro. beta1-/- cells showed delayed and reduced myogenic differentiation compared to wildtype and heterozygous (beta1+/-) ES cells. RT-PCR analysis demonstrated delayed expression of skeletal muscle-specific genes in the absence of beta1 integrin. Immunofluorescence studies with antibodies against the sarcomeric proteins myosin heavy chain, titin, nebulin, and slow C-protein showed that myotubes formed, but their number was reduced and the assembly of sarcomeric structures was retarded. In contrast, neuronal cells differentiating from beta1-/- ES cells appeared earlier than wildtype and heterozygous (beta1+/-) ES cells. This was shown by the accelerated expression of neuron-specific genes and an increased number of neuronal cells in beta1-/- embryoid bodies. However, neuronal outgrowth was retarded in the absence of beta1 integrin. No functional difference between wildtype and beta1-/- cells was found with respect to secretion of gamma-aminobutyric acid, the main neurotransmitter of ES cell-derived neuronal cells. The lineage-specific effects of loss of beta1 integrin function, that is the inhibition of mesodermal and acceleration of neuroectodermal differentiation, were supported by differential expression of genes encoding lineage-specific transcription factors (Brachyury, Pax-6, Mash1) and signaling molecules (BMP-4 and Wnt-1). Because of the reduced and delayed expression of the BMP-4 encoding gene in beta1-/- cells, we analyzed in wildtype and beta1-/- cells the regulatory role of exogenously added BMP-4 on the expression of the mesodermal and neuronal marker genes, Brachyury and wnt-1, respectively. The data suggest that BMP-4 plays a regulatory role during differentiation of wildtype and beta1-/- cells by modifying mesodermal and neuronal pathways. The reduced expression of BMP-4 in beta1-/- cells may account for the accelerated neuronal differentiation in beta1-/- ES cells.

Animals↗

PubMed1998

Production and characterization of monoclonal anti-idiotypic antibody exhibiting a catalytic activity similar to carboxypeptidase A.

A new approach for producing catalytic anti-idiotypic antibody was developed. A monoclonal anti-idiotypic antibody which was induced against carboxypeptidase A (CPA) showed the catalytic activity similar to the original antigen. The activity of the catalytic antibody was investigated. Rabbits were immunized by bovine pancreas carboxypeptidase A. The antiserum was purified and used as antigen to immunize BALB/c mice to induce monoclonal anti-idiotypic antibodies. Screened for enzymatic activities, the monoclonal antibody 32C3 showed esterase activity. The hydrolysis of hippuryl-DL-phenyllactic acid by McAb 32C3 followed the enzymatic kinetics. In our experimental system, Kcat value was 0.0123 min-1 and Km was 0.04M. The acceleration rate was 1750 times compared to the rate of self-hydrolysis of the substrate. This hydrolysis reaction can be competitively inhibited by hydrocinnamic acid. This method could be effective to obtain catalytic antibodies with the characters close to natural enzymes.

Animals↗