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Biomedical subjects

Min Hong

Publications and source records attributed to Min Hong.

At least 19 recordsLinked to original sources
PubMed2006

A novel fibrinolytic serine protease from the polychaete Nereis (Neanthes) virens (Sars): purification and characterization.

A novel fibrinolytic serine protease has been identified and purified to homogeneity from the coelomic fluid of polychaete Nereis (Neanthes) virens (Sars), and named N-V protease. N-V protease is a 29kDa single chain protein with an isoelectric point of pH 4.5. It hydrolyzes Aalpha-chain of fibrinogen with a high efficiency, and the Bbeta- and gamma-chains (Aalpha>Bbeta>gamma) with a lower efficiency. The proteolytic activity peaks at pH 7.8 is 45 degrees C. The activity is completely inhibited by serine protease inhibitors DFP (I(50)=5.8 x 10(-4)M) and PMSF (I(50)=5.5 x 10(-2)M), and almost completely by TLCK (I(50)=7.7 x 10(-1) M). But aprotinin, elastinal, SBTI, benzamidine, PCMB, EDTA, EGTA, iodoacetate, E64, and beta-mercaptoethanol have no effect on the protease activity. Therefore, N-V protease is identified as a serine protease. The primary amino acid sequence of N-V protease was determined by mass spectrometry (N-V protease, No. P83433). According to the MALDI-TOF MS analysis, there is no existing protein in the NCBI Non-redundant Protein Sequence Database that matches the N-V protease sequence. Therefore, N-V protease is a novel and special protein in N. virens. Furthermore, we have successfully established an expression cDNA library from the whole body of N. virens (data not shown).

Amino Acid Sequence↗
PubMed2006

Modulation of calcium wave propagation in the dendrites and to the soma of rat hippocampal pyramidal neurons.

Repetitive synaptic stimulation in the stratum radiatum (SR) evokes large amplitude Ca2+ waves in the thick apical dendrites of hippocampal CA1 pyramidal neurons. These waves are initiated by activation of metabotropic glutamate receptors (mGluRs), which mobilize inositol-1,4,5-trisphospate (IP3) and release Ca2+ from intracellular stores. We explored mechanisms that modulate the spatial properties of these waves. Higher stimulus current evoked waves of increasing spatial extent. Most waves did not propagate through the soma; the majority stopped close to the junction of the soma and apical dendrite. Pairing strong stimulation with one electrode and subthreshold stimulation with another (associative activation) extended the waves distally but failed to extend waves into the cell body. Pairing synaptic stimulation with backpropagating action potentials enhanced the likelihood of wave generation but did not extend the waves to the somatic region. Priming the stores with Ca2+ entry through voltage dependent channels modulated wave properties but did not extend them past the dendrites. These results are consistent with propagation failing due to the dilution of synaptically generated IP3 as it diffuses into the large volume of the soma (impedance mismatch). Synaptically activating waves in the presence of low concentrations of carbachol, which probably increased the tonic level of IP3 throughout the cell, enhanced the extent of propagation and generated waves that invaded the soma, as long as low-affinity indicators were used to detect the [Ca2+]i changes. Consistent with this explanation direct injection of IP3 into the soma promoted wave propagation into this region. Ca2+ waves that propagated through the cell body were interesting because they did not fill the volume of the soma, but passed through the centre, often with large amplitude. These waves may be particularly effective in activating gene expression and protein synthesis.

Action Potentials↗
PubMed2006

Quality evaluation of Cordyceps through simultaneous determination of eleven nucleosides and bases by RP-HPLC.

A new RP-HPLC method has been developed for the simultaneous determination of 11 nucleosides and bases, including adenosine, cordycepin, cytidine, guanosine, inosine, thymidine, uridine, cytosine, guanine, thymine, and uracil in Cordyceps. Determination was achieved on a Zorbax 300SB C18 analytical column (4.6 x 250 mm id, 5 mm) using gradient elution with diode-array detection. All calibration curves showed good linearity (r2 > 0.9995) within the test ranges. The developed method was simple, rapid, and accurate, and showed good reproducibility for the quantification of 11 nucleosides and bases in natural and cultured Cordyceps with both intra- and inter-day variations of less than 1.8%. Furthermore, hierarchical clustering analysis based on the typical peaks of adenosine, cordycepin, and inosine in HPLC profiles from the 11 tested samples showed that natural and cultured Cordyceps were in different clusters, which could provide a means of discriminating between Cordyceps of different origins. Thus, adenosine, cordycepin, and inosine could be used as markers for quality control of Cordyceps.

Calibration↗
PubMed2006

Structural and functional characterization of herpes simplex virus 1 immediate-early protein infected-cell protein 22.

Of the five HSV1 immediate-early proteins, infected-cell protein 22 (ICP22), the product of the Us1 gene, is a member whose function is less understood. In order to promote better understanding of the role of ICP22 in viral replication, mutation and fluorescence techniques were used to investigate the biochemical relationship between ICP22's structure and nuclear localization, and the CAT assay was used to analyze the relationship between ICP22's structure and its transcriptional repression. The results of these experiments implied (i) ICP22 is localized to small dense nuclear bodies and is paired with the SC-35 domain in the nucleus, (ii) ICP22 localization in a punctate state requires completion of the main sequence which includes the 1-320th amino acids, (iii) a conservative mutation in the nucleotidylylation site is important for its nuclear localization and transcriptional repression, and (4) despite possessing the same amino acid sequence as the ICP22 carboxyl-terminal, Us1.5 was distinct from ICP22 in location and function.

Animals↗
PubMed2006

[Monitoring of bcr/abl fusion gene by interphase-dual-color and dual-fusion fluorescence in situ hybridization in CML after allo-HSCT].

This study was aimed to investigate the sensitivity and clinical application value of interphase-dual-color and dual-fusion fluorescence in situ hybridization (DD-FISH). The minimal residual disease (MRD) in 19 patients with chronic myelogenous leukemia (CML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) was detected by DD-FISH, and the detected results were compared with those of conventional cytogenetics (CC) and reverse transcription-polymerase chain reaction (RT-PCR). The samples were collected from bone marrow or peripheral blood or smears of bone marrow. The results indicated that 14 out of 19 patients achieved and maintained continuous complete molecular remission after transplantation. In these patients, CC assay displayed normal donor karyotype, result of RT-PCR was negative, complete donor chimerism was detected after 2 months of transplantation, result of DD-FISH was negative, average time of the follow-up survey was 11.25 months, MRD did not increase. Results of CC and RT-PCR in 1 patient showed negative, while FISH of sex chromosome showed mixed chimerism, result of DD-FISH was positive, MRD did not increase, no therapy was given for this patient, clinical state of patient was stable. Three patients with hematological relapse demonstrated obvious increase of MRD detected by DD-FISH and sex FISH, result of RT-PCR was found positive in them, but the abnormal result of CC was observed only in 1 patient. After donor lymphocyte infusion and imatinib mesylate treatment, these 3 patients achieved cytogenetic remission again, results of DD-FISH, CC and PCR were negative in them. DD-FISH, CC and PCR in bone marrow and peripheral blood from one patient with extramedullary relapse revealed negative results, and the complete chimerism was found in this patient. It is concluded that interphase-dual-color and dual-fusion fluorescence in situ hybridization is a more reliably sensitive and practicable method for monitoring MRD in patients with CML after allo-HSCT, and can be used in detection of chromosome sample and blood or bone marrow smears. Dynamic detection of bcr/abl fusion gene level by FISH may predict disease changes and guide individual therapy.

Adolescent↗
PubMed2005

Heroin affects purine nucleotides catabolism in rats in vivo.

To investigate the effect of heroin on purine nucleotides catabolism, a rat model of heroin administration and withdrawal was established. Concentrations of uric acid, creatinine, and urea nitrogen in plasma and ADA in plasma, brain, liver, and small intestine were tested. When two heroin administration groups were compared with the control group, the concentrations of plasma uric acid and ADA in plasma, brain, liver, and small intestine increased, whereas the plasma urea nitrogen concentrations in two heroin administration groups and the plasma creatinine concentration in the 3-day heroin administration group did not increase. It seemed that heroin exposure for a short time did not affect renal clearance rate notably. When two withdrawal groups were compared with two heroin administration groups, the concentrations of plasma uric acid and ADA in liver and small intestine decreased, but there was no significant reduction in ADA concentrations of the brain, while the plasma ADA concentrations in the two withdrawal groups were significantly higher than those of two heroin administration groups. When the two withdrawal groups were compared with the control group, there was no significant difference in the concentrations of plasma uric acid and ADA in liver and small intestine, while the concentrations of ADA in plasma and brain were still higher than those of the control group. The results imply that heroin administration may enhance the catabolism of purine nucleotides in the brain and other tissues by increased concentration of ADA and the effect may last for a long time in the brain.

Adenosine Deaminase↗
PubMed2005

Transcriptional regulation of the Grp78 promoter by endoplasmic reticulum stress: role of TFII-I and its tyrosine phosphorylation.

TFII-I is a signal-induced multi-functional transcription factor that has recently been implicated as a regulatory component of the endoplasmic reticulum (ER) stress response. TFII-I acts through ER stress-induced binding to the ER stress element, which is highly conserved in promoters of ER stress-inducible genes such as Grp78/BiP. Interestingly, its tyrosine phosphorylation sites are required for its activation of the Grp78 promoter. Toward understanding the link between TFII-I, the tyrosine kinase signaling pathway, and Grp78 activation, we discovered that Tg stress induces a dramatic increase of TFII-I phosphorylation at Tyr248 and localization of this form of TFII-I to the nucleus. Chromatin immunoprecipitation analysis further reveals enhanced TFII-I binding to the Grp78 promoter in vivo upon ER stress. Previously, we reported that genistein, a general inhibitor of tyrosine kinase, could suppress ER stress induction of Grp78 by inhibiting complex formation on the ER stress element; however, the mechanism is not known. Consistent with TFII-I being a target of genistein suppression, we observed that genistein could suppress Tg stress-induced phosphorylation of TFII-I. We further demonstrate that c-Src, which is one of kinases identified to mediate phosphorylation of TFII-I at Tyr248, is activated by Tg stress and is able to stimulate the Grp78 promoter activity. Lastly, using stable cell lines with suppressed TFII-I levels, we show that TFII-I is required for optimal induction of Grp78 by ER stress. Our studies provide a molecular link that connects the c-Src tyrosine kinase transduction pathway to ER stress-induced transcriptional activation of Grp78 mediated by TFII-I.

Animals↗
PubMed2004

Endoplasmic reticulum stress triggers an acute proteasome-dependent degradation of ATF6.

ATF6, a 670 amino acid endoplasmic reticulum (ER) transmembrane glycoprotein with the electrophoretic mobility of a 90 kDa protein, is a key transcriptional activator of the unfolded protein response (UPR) that allows mammalian cells to maintain cellular homeostasis when the cells are subjected to a variety of environmental and physiological stress. Previous studies have established that ATF6 is a short-lived protein, the activation of which involves relocation from the ER to the Golgi where it is cleaved by the S1P/S2P protease system to generate a nuclear form that acts as a transcriptional activator for ER-stress inducible target genes such as Grp78/BiP. We report here that in addition to this process, ER-stress mediated by thapsigargin triggers an acute proteasomal degradation of the pre-existing pool of p90ATF6 independent of S1P/S2P cleavage. We showed that ATF6 is a direct target of proteasome-ubiquitin pathway, and this process can be suppressed by proteasome inhibitors, ALLN and MG115. We further observed that in non-stressed cells, p90ATF6 can be stabilized by MG115 but not ALLN and that treatment of cells with MG115 results in Grp78 induction in the absence of ER stress. These studies suggest that ER-stress induced acute, transit degradation of p90ATF6 could represent a novel cellular defense mechanism to prevent premature cell death resulting from p90ATF6 activation. Further, inhibition of proteasome activity can result in chaperone protein gene induction through stabilization of p90ATF6 as well as accumulation of malfolded proteins.

Activating Transcription Factor 6↗
PubMed2004

Macrophages are activated by 17beta-estradiol: possible permission role in endometriosis.

On the basis of the common occurrence of high concentration of estrogen and activated macrophages in patients with endometriosis, we postulate that interaction between 17beta-estradiol and macrophage may be an important affair in endometriosis. So our study was focused on the effect of 17beta-estradiol on macrophage. First morphology of macrophages was examined with environmental scanning electron microscopy. Increased size, extension of more microvilli, expression of retraction fibers and elaboration of membrane ruffles were detected in 17beta-estradiol treated macrophages. Then Nitrate and nitrite level in the supernatant was measured by the method of Griess and iNOS expression was analyzed using immunohistochemical staining. It showed that 17beta-estradiol could induce NO release from peritoneal macrophages and expression of iNOS was increased. Also more TNF-alpha in supernatant that was measured by MTT via L929 cell was produced by macrophages under the inducing of 17beta-estradiol. Furthermore, [Ca2+]i, which was viewed by microscope in a laser scanning confocal unit, elevated 39.8% in peritoneal macrophages after 17beta-estradiol 100 nmol/L treated. The results above demonstrated that peritoneal macrophage had been activated in both morphology and cytokine line when interaction with 17beta-estradiol, which indicated that macrophage activated by 17beta-estradiol might play a permission role in development of endometriosis.

Animals↗
PubMed2004

[Determination of phenylalanine and tyrosine in serum by high-performance liquid chromatography with fluorescent detection].

OBJECTIVE: To determine phenylalanine and tyrosine in serum by high-performance liquid chromatography (HPLC) method. METHODS: Serum precipitated with perchloric acid was isocratically eluted using a base-deactivated C8 column with 10% acetonitrile in water as the mobile phase. The flow rate was 1.0 ml/min. Fluorescent detector worked at an excitation wavelength of 210 nm and emission wavelength of 303 nm. RESULTS: Good linearity was observed in the range of 12.2 approximately 1 220.0 micromol/L for phenylalanine, the intra- and inter-assay coefficients of variation (CV) were 4.07% and 7.17% respectively, and the average recovery was 102.5%. There also was a good linearity in the range of 5.5 approximately 550.0 micromoL/L for tyrosine. The intra- and inter-assay coefficients of variation were 2.99% and 5.23% respectively, and the average recovery was 102.2%. The total assay time for the serum sample was within 30 min. We found a good correlation compared with HPLC ultraviolet detection. CONCLUSION: This method is simple, rapid, accurate in measuring phenylalanine and tyrosine in serum quantitatively.

Adolescent↗
PubMed2003

Underglycosylation of ATF6 as a novel sensing mechanism for activation of the unfolded protein response.

ATF6 is a key transcriptional activator of the unfolded protein response (UPR), which allows mammalian cells to maintain cellular homeostasis when they are subjected to a variety of environmental and physiological stresses that target the endoplasmic reticulum (ER). ATF6, a 90-kDa ER transmembrane protein, contains three evolutionarily conserved N-linked glycosylation sites within its carboxyl luminal domain. Although it is well established that p90ATF6 activation requires transit from the ER to the Golgi, where it is cleaved by the S1P/S2P protease system to generate a nuclear form p60ATF6 that acts as a transcriptional activator, the functional significance of p90ATF6 N-linked glycosylation is unknown. Here we show that ER Ca(2+) depletion stress, a triggering mechanism for the UPR, induces the formation of ATF6(f), which represents de novo partial glycosylation of newly synthesized p90ATF6. By mutating a single amino acid within the N-linked glycosylation site closest to the carboxyl terminus of p90ATF6, we recreated ATF6(f). This mutation sharply reduces p90ATF6 association with calreticulin, a major Ca(2+)-binding chaperone for N-glycoprotein. We further determined that ATF6(f) exhibits a faster rate of constitutive transport to the Golgi, resulting in a higher level of p60ATF6 in the nucleus and stronger transactivating activity in the absence of ER stress. Additional analysis of p90ATF6 mutants targeting single or multiple N-glycosylation sites also showed higher constitutive transactivating activity than wild type ATF6. Because accumulation of underglycosylated proteins in the ER is a potent inducer for the UPR, these studies uncover a novel mechanism whereby the glycosylation status of p90ATF6 can serve as a sensor for ER homeostasis, resulting in ATF6 activation to trigger the UPR.

Activating Transcription Factor 6↗
PubMed2003

[Effect of morphine on expression of gene of enzymes related to purine nucleotide metabolism in c6 glioma].

OBJECTIVE: To investigate the effect of morphine on catabolism and anabolism of purine nucleotide in c6 glioma cells. METHODS: C6 glioma cells were cultured and divided into 3 groups: 1) morphine group: morphine (10 micro g/ml culture) was added for 6 h, 12 h, 24 h, 48 h, and 72 h; 2) morphine + naloxone group: naloxone (1 micro mol/L) was added for 1 hour and then morphine (10 micro g/ml) was added for 24 hours; and 3) control group: normal saline was used for 6, 12, 24, 48, and 72 hours. The C6 glioma cells were centrifuged. RT-PCR was used to examine the gene transcripts of key enzymes of purine salvage way, hypoxanthine-guanine-phosphoribosyl transferase (HGPRT) and adenylate kinase (AK). RT-PCR-Southern blotting was used to examine the gene transcripts of key enzymes of purine salvage way, xanthine dehydrogenase (XD)/xanthine oxidase (XO) mRNA. RESULTS: Compared with that in the control group, the transcript of AK mRNA was significantly lower in the C6 cells treated with morphine for 24 hours, and began to re-increase 48 hours after morphine treatment. The transcript of AK mRNA remained at a low level after treatment of naloxone for 1 hour and treatment of morphine for 24 hours. The levels of transcript of HGPRT mRNA were lower in the morphine group than in the control group at all time points after treatment. However, the level of transcript of HGPRT mRNA 72 hours after treatment was higher in the morphine group than in the control group. The level of transcript of HGPRT mRNA 24 hours after exposure to morphine in the naloxon2 + morphine group was still lower than in the control group. The levels of transcripts of XD/XO mRNA were significantly higher after exposure to morphine in comparison with those in the control group at all time points after treatment. However, the levels of XD/XO mRNA 24 hours after exposure to morphine in the naloxone + morphine group recovered to the normal level. CONCLUSION: The downregulation effect of morphine on the gene expression of AK and HGPRT may not be mediated by mu receptor. The upregulation effect of morphine on the gene expression of XD/XO may be mediated by mu receptor. Naloxone reverses the effect of morphine on enhancement of XD/XO gene expression and cannot reverse the inhibitory effect of morphine on HGPRT and AK gene expression.

Adenosine Kinase↗
PubMed2003

Genomic organization of Trypanosoma brucei kinetoplast DNA minicircles.

The sequences of seven new Trypanosoma brucei kinetoplast DNA minicircles were obtained. A detailed comparative analysis of these sequences and those of the 18 complete kDNA minicircle sequences from T. brucei available in the database was performed. These 25 different minicircles contain 86 putative gRNA genes. The number of gRNA genes per minicircle varies from 2 to 5. In most cases, the genes are located between short imperfect inverted repeats, but in several minicircles there are inverted repeat cassettes that did not contain identifiable gRNA genes. Five minicircles contain single gRNA genes not surrounded by identifiable repeats. Two pairs of closely related minicircles may have recently evolved from common ancestors: KTMH1 and KTMH3 contained the same gRNA genes in the same order, whereas KTCSGRA and KTCSGRB contained two gRNA genes in the same order and one gRNA gene specific to each. All minicircles could be classified into two classes on the basis of a short substitution within the highly conserved region, but the minicircles in these two classes did not appear to differ in terms of gRNA content or gene organization. A number of redundant gRNAs containing identical editing information but different sequences were present. The alignments of the predicted gRNAs with the edited mRNA sequences varied from a perfect alignment without gaps to alignments with multiple mismatches. Multiple gRNAs overlapped with upstream gRNAs, but in no case was a complete set of overlapping gRNAs covering an entire editing domain obtained. We estimate that a minimum set of approximately 65 additional gRNAs would be required for complete overlapping sets. This analysis should provide a basis for detailed studies of the evolution and role in RNA editing of kDNA minicircles in this species.

Animals↗
PubMed2003

[Effect of TCTS on experimental endometriosis of rats].

OBJECTIVE: To study the effect of TCTS on endometriosis rats. METHOD: On the model of surgical induced rat endometriosis, weight and pathological changes of endometrial transplant and serum hormones were observed. RESULT: Weight of endometrial transplants was reduced by TCTS 11.2 g.kg-1 and 22.5 g.kg-1 and transplants of TCTS treated rat showed poorly developed epithelium, thinner stroma, fewer stromal cells and glands. At the same time elevated serum E2, FSH and LH were reduced by TCTS. CONCLUSION: TCTS can inhibit the growth of endometrial transplants, which is related with serum hormone, especially E2.

Animals↗
PubMed2003

[Effect of extract from shenghua decoction on myoelectric activity of rabbit uterine muscle in the latest period of pregnancy].

OBJECTIVE: To elucidate the difference between uterus body and cervix under the intervention of Shenghua decoction, and to observe the rabbit uterine muscle in the latest period of pregnancy for the way of myoelectric activity. METHOD: PowerLab/8s was used to record myoelectric activity of rabbit muscle in uterus body and cervix which was in a general anaesthesia state induced by urethane. RESULT: Myoelectric activities of rabbit uterine smooth muscle in the latest period of pregnancy was enhanced in vivo by being treated with Shenghua decoction 40 mg x kg(-1) (P < 0.01) while cervix myoelectric activities had no significant change (P < 0.05). CONCLUSION: Myoelectric activities of rabbit uterine muscle in the latest period of pregnancy are enhanced by being treated with Shenghua decoction so its hemostatic effect can be represented via the constriction of uterus body. Shenghua decoction is beneficial for child delivery because cervix myoelectric activities have no significant change under the intervention of Shenghua decoction while the myoelectric activities of uterus body are increased significantly.

Action Potentials↗
PubMed2002

Phenylethanolamine N-methyl transferase expression in mouse thymus and spleen.

Catecholamines usually are found in neurons and chromaffin cells of mammals. In this study, surprisingly high levels of the epinephrine synthesizing enzyme phenylethanolamine N-methyl transferase (PNMT) were detected in the thymus of young mice. Levels of PNMT activity in the thymus were comparable to levels in the brainstem and were suppressed by the PNMT inhibitor LY134046. PNMT mRNA was localized with in situ hybridization throughout the thymus, but levels were approximately twofold higher in the cortex than in the medulla. PNMT activity was barely detectable in the spleen, and only a few cells expressing PNMT mRNA were located in the marginal zone of the white pulp. These findings suggest that cells in the thymus of young mice have the ability to synthesize epinephrine.

Age Factors↗
PubMed2002

PEG and DBBF modified porcine hemoglobin and their oxygen-carrying capacity.

Modifications of proteins with polyethylene glycol (PEG) have been proven to enlarge molecule size of proteins, to prolong their retention time in the circulation as well as blunt immune or allergic reactions. Hemoglobin cross-linked with small molecular modifiers turns out to be more stable and to have better oxygen carrying capacity. In the present study, four derivatives of PEG with different activation groups, and several PEGs with different molecular weights were covalently bound to porcine hemoglobin (pHb). PEG-pHbs exhibited a variety of differences in their properties depending on the molecular weights of the used PEGs, the amounts of bound PEGs and the presence or absence of allosteric cofactors. The optimal modification conditions for bis (3, 5-dibromosalicyl) fumarate (DBBF) as well as the physical features and oxygen carrying capacity of DBBF-modified pHb were evaluated. Furthermore, both PEG and DBBF were used simultaneously to modify pHb. The results indicate that the pHbs modified with PEG and DBBF have more stable tetrameric conformations with a molecular weight of 107 kD. Their oxygen half-saturation pressure (P(50)) is around 3.33 kPa which approximates the physiological P(50) of human red blood cells.

Animals↗