Biomedical subjects

Fang Xu

Publications and source records attributed to Fang Xu.

At least 55 records · Page 3Linked to original sources

PubMed2004

A new method of preventing bile duct injury in laparoscopic cholecystectomy.

AIM: Of all the complications of laparoscopic cholectecystomy, bile duct injury (BDI) is the most serious complication. The prevention of injury to the common bile duct (CBD) remains a significant concern in laparoscopic cholecystectomy (LC). Different kinds of methods have been advanced to avoid this injury but no single method has gained wide acceptance. Because of various limitations of current methodologies we began a study using cold light illumination of the extrahepatic biliary system (light cholangiography LCP) to better visualize this area and thereby reduce the risk of bile duct injury. METHODS: Thirty-six patients with cholelithiasis were divided into two groups. Group I (16 cases) received LCP and group II (20 cases) received methelenum coeruleum cholangiography (MCCP). In group I cold light was used to illuminate the common bile duct by leading an optical fiber into the common duct with a duodenoscope at the time of LC. The light coming from the fiber in the CBD could clearly illuminate the location of CBD and hepatic duct establishing its location relative to the cystic duct. This method was compared with the dye injection technique using methelenum coeruleum. RESULTS: In group I thirteen cases were successfully illuminated and three failed. The cause of three failed cases was due to the difficulty in inserting the fiber into the ampulla of Vater. No complications occurred in the thirteen successful cases. In each of these successful cases the location of the common and hepatic ducts was clearly seen differentiating the ductal system from surrounding anatomy. In ten cases both the left and right hepatic ducts could be seen and in three only the right hepatic ducts were seen. In four of the thirteen cases, cystic ducts were also seen. In group II, eighteen of the twenty cases were successful. The location of extrahepatic ducts became blue differentiating the ductal system from surrounding anatomy. Two cases failed due to a stone obstructing the cystic duct, and extravisation of the dye turned the entire area blue. LCP showed the common and hepatic ducts more clearly than MCCP. CONCLUSION: LCP is the only technique that can clearly and directly show the location of the extrahepatic biliary system and may be useful in selecting cases of uncertain anatomy in the prevention of bile duct injury.

Adult↗

PubMed2004

Differential thapsigargin-sensitivities and interaction of Ca2+ stores in human SH-SY5Y neuroblastoma cells.

In human SH-SY5Y neuroblastoma cells, two distinct intracellular Ca2+ stores, a KCl-/caffeine-sensitive and a carbachol-/IP3-sensitive store, were demonstrated previously. In this study, responses of these two intracellular Ca2+ stores to thapsigargin were characterized. Ca2+-release from these stores was evoked either by high K+ (100 mM KCl) or by 1 mM carbachol, and changes in the intracellular Ca2+ level were monitored using Fura-2 fluorimetry. A sequential stimulation protocol (KCl-->carbachol or vice versa) allowed evaluation of the individual contribution of different Ca2+ stores to the evoked intracellular Ca2+ ([Ca2+]i)-transients and the dynamic interaction between them. Thapsigargin (0.05 nM - 20 microM) alone induced a [Ca2+]i-transient. Both the carbachol- and the KCl-evoked [Ca2+]i-transients were inhibited by thapsigargin, but with very different sensitivities. Thapsigargin inhibited the carbachol-evoked [Ca2+]i-transients with (IC50 = 0.353 nM) or without (IC50 = 0.448 nM) a KCl-prestimulation, but an additional small component, with a much lower sensitivity (IC50=4814 nM), was observed in the absence of a KCl-prestimulation. In contrast, the KCl-evoked [Ca2+]i-transients displayed only one component with a very low sensitivity to thapsigargin in both absence (IC50=3343 nM) and presence (IC50=6858 nM) of a carbachol-prestimulation. These findings suggest that the sarco-/endoplasmic reticular Ca2+ ATPases associated with the KCl-/caffeine- and carbachol-/IP3-sensitive intracellular Ca2+ stores differ from each other, either in types or in their post-translational modification. Such difference might play important role in the regulation of neuronal Ca2+ homeostasis.

Atropine↗

PubMed2004

Response of REV3 promoter to N-methyl-N'-nitro-N-nitrosoguanidine.

Previously, we have shown that low concentration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) led to the upregulation of REV3 gene at transcriptional level in cultured human amnion FL cells. In this study, using bioinformatic analysis the putative binding sites for different transcription factors were found to exist in REV3 gene promoter region. A 2570-bp fragment of the 5' flanking region of REV3 gene was amplified by PCR from PAC clone RP3-415N12 and inserted into the pGL3-Basic reporter vector. Dual-luciferase reporter assay demonstrated that the reconstructed plasmid did respond to MNNG exposure in transfected FL cells. Several variants of the reporter plasmids with different deletions of the REV3 promoter region were also constructed and their promoter strength was analyzed. It was found that the MNNG response element might locate at the REV3 gene promoter region -404 to -102 between two Sma1 sites. The shortest responsive fragment containing the putative binding sites for transcription factors CREBP, AP-2, NF-kappaB, and SP1 was also identified.

Base Sequence↗

PubMed2004

High-level expression of ABCG5 and ABCG8 attenuates diet-induced hypercholesterolemia and atherosclerosis in Ldlr-/- mice.

Transgenic mice expressing human ABCG5 (G5) and ABCG8 (G8) have decreased fractional absorption and increased biliary secretion of cholesterol, but their plasma cholesterol levels are unchanged (males) or modestly reduced (females). To determine whether increased expression of G5 and G8 can ameliorate hypercholesterolemia in mice lacking LDL receptors (LDLRs), we examined the effects of G5G8 transgene expression on cholesterol metabolism and atherosclerosis in Ldlr-/- mice. In chow-fed Ldlr-/- mice, the G5G8 transgene reduced fractional absorption of dietary cholesterol by 50% and increased biliary cholesterol levels by 60% but did not affect plasma cholesterol levels. On a Western diet (21% fat, 0.2% cholesterol), G5G8Tg; Ldlr-/- mice had a 30% reduction in the level of hepatic cholesterol and 45% lower plasma cholesterol levels than the Ldlr-/- mice. After 6 months on the Western diet, the atherosclerotic lesion area in the aortic root and arch was approximately 70% lower in the G5G8Tg;Ldlr-/- than in the Ldlr-/- mice and was correlated with the plasma cholesterol levels. These results demonstrate that increased expression of G5 and G8 attenuates diet-induced hypercholesterolemia in Ldlr-/- mice, resulting in a significant reduction in plasma levels of cholesterol and aortic atherosclerotic lesion area.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed2004

Modeling microlenses by use of vectorial field rays and diffraction integrals.

A nonparaxial vector-field method is used to describe the behavior of low-f-number microlenses by use of ray propagation, Fresnel coefficients and the solution of Maxwell equations to determine the field propagating through the lens boundaries, followed by use of the Rayleigh-Sommerfeld method to find the diffracted field behind the lenses. This approach enables the phase, the amplitude, and the polarization of the diffracted fields to be determined. Numerical simulations for a convex-plano lens illustrate the effects of the radii of curvature, the lens apertures, the index of refraction, and the wavelength on the variations of the focal length, the focal plane field distribution, and the cross polarization of the field in the focal plane.

Journal Article↗

PubMed2004

A sensitive method for the determination of the novel cholinesterase inhibitor ZT-1 and its active metabolite huperzine A in rat blood using liquid chromatography/tandem mass spectrometry.

ZT-1 has been developed as a novel acetylcholinesterase inhibitor, but is rapidly degraded to huperzine A (Hup A) in water or aqueous organic solvents. A sensitive method has been developed for simultaneous determination of ZT-1 and its active metabolite Hup A in blood, and was applied to the investigation of the pharmacokinetics of ZT-1 in rats. The method involves immediate hydrogenation of ZT-1 with sodium borohydride to the stable form rZT-1 following blood sampling. The NaBH4-treated blood sample is then submitted to liquid-liquid extraction, and the resultant extract is analyzed by liquid chromatography with electrospray ionization and tandem mass spectrometry. Huperzine B is used as internal standard for the quantification. ZT-1 was found to be rapidly absorbed in the intestinal tract, with a time to reach the peak blood concentration (Tpeak) of 5 min after an intragastric dose of ZT-1 embedded in povidone to rats at 0.5 mg ZT-1/kg. The mean maximum blood concentration (Cmax) and area under the blood level-time curve (AUC(0 --> 8)) of ZT-1 were 1.57 ng/mL and 0.48 ng. h/mL, respectively. The Tpeak, Cmax, and AUC values of the metabolite Hup A were 0.22 h, 109.9 ng/mL, and 96.3 ng. h/mL, respectively. Following an intravenous dose of 0.1 mg ZT-1/kg rat body weight, the blood concentration of ZT-1 was higher than that of Hup A, and the AUC(0 --> 8) values were 26.2 ng. h/mL for ZT-1 and 6.0 ng. h/mL for Hup A. The elimination half-lives (T1/2) of ZT-1 and Hup A were 0.68 and 1.47 h, respectively. The oral bioavailability (F) of intact ZT-1 in rats treated with ZT-1 embedded in povidone was very low, 0.37%.

Alkaloids↗

PubMed2004

Growth characteristics and eicosapentaenoic acid production by Nannochloropsis sp. in mixotrophic conditions.

Nannochloropsis sp. was grown under mixotrophic conditions with 30 mM glucose as carbon source, reaching 507 mg dry wt l(-1) after 8 d. This was 1.4-fold of that obtained under photoautotrophic conditions. Under mixotrophic and photoautotrophic cultivations, the net photosynthetic rate of Nannochloropsis sp. did not change but the respiratory rate increased in the mixotrophic cultivation. The yield of eicosapentaenoic acid was 22 mg l(-1) in the mixotrophic cultivation and 20 mg l(-1) under the photoautotrophic cultivation.

Bioreactors↗

PubMed2004

Growth and fatty acid composition of Nannochloropsis sp. grown mixotrophically in fed-batch culture.

The cell growth and eicosapentaenoic acid (EPA) yields of Nannochloropsis sp. were enhanced in the fed-batch cultures. With feeding glucose solution, the biomass reached 1.1 g dry wt l(-1) after 10 days' culture, which was 40% higher than that obtained in the batch culture (0.8 g dry wt l(-1)). With supplement of nitrate solution, the biomass reached 1 g dry wt l(-1), and reached the stationary phase 2 days earlier than the others. The maximum of biomass (1.2 g dry wt l(-1)) was obtained with the supplement of the mixture of glucose and nitrate solution. The EPA yields of Nannochloropsis sp. after 10 days' growth in the fed-batch cultures were 52 mg l(-1), 43 mg l(-1) and 56 mg l(-1) with, respectively, addition of nitrate, glucose and both together. In batch culture only 35 mg EPA l(-1) was obtained.

Animals↗

PubMed2004

Isoflurane reduces the carbachol-evoked Ca2+ influx in neuronal cells.

BACKGROUND: The authors previously reported that the isoflurane-caused reduction of the carbachol-evoked cytoplasmic Ca transient increase ([Ca]cyt) was eliminated by K or caffeine-pretreatment. In this study the authors investigated whether the isoflurane-sensitive component of the carbachol-evoked [Ca]cyt transient involved Ca influx through the plasma membrane. METHODS: Perfused attached human neuroblastoma SH-SY5Y cells were exposed to carbachol (1 mm, 2 min) in the absence and presence of isoflurane (1 mm) and in the absence and presence of extracellular Ca (1.5 mm). The authors studied the effect of the nonspecific cationic channel blocker La (100 microm), of the L-type Ca channel blocker nitrendipine (10 microm), and of the N-type Ca channel blocker omega-conotoxin GVIA (0.1 microm) on isoflurane modulation of the carbachol-evoked [Ca]cyt transient. [Ca]cyt was detected with fura-2 and experiments were carried out at 37 degrees C. RESULTS: Isoflurane reduced the peak and area of the carbachol-evoked [Ca]cyt transient in the presence but not in the absence of extracellular Ca. La had a similar effect as the removal of extracellular Ca. Omega-conotoxin GVIA and nitrendipine did not affect the isoflurane sensitivity of the carbachol response although nitrendipine reduced the magnitude of the carbachol response. CONCLUSIONS: The current data are consistent with previous observations in that the carbachol-evoked [Ca]cyt transient involves both Ca release from intracellular Ca stores and Ca entry through the plasma membrane. It was found that isoflurane attenuates the carbachol-evoked Ca entry. The isoflurane sensitive Ca entry involves a cationic channel different from the L- or N- type voltage-dependent Ca channels. These results indicate that isoflurane attenuates the carbachol-evoked [Ca]cyt transient at a site at the plasma membrane that is distal to the muscarinic receptor.

Anesthetics, Inhalation↗

PubMed2004

Disruption of cholesterol homeostasis by plant sterols.

The ABC transporters ABCG5 and ABCG8 limit absorption and promote excretion of dietary plant sterols. It is not known why plant sterols are so assiduously excluded from the body. Here we show that accumulation of plant sterols in mice lacking ABCG5 and ABCG8 (G5G8-/- mice) profoundly perturbs cholesterol homeostasis in the adrenal gland. The adrenal glands of the G5G8-/- mice were grossly abnormal in appearance (brown, not white) due to a 91% reduction in cholesterol content. Despite the very low cholesterol levels, there was no compensatory increase in cholesterol synthesis or in lipoprotein receptor expression. Moreover, levels of ABCA1, which mediates sterol efflux, were increased 10-fold in the G5G8-/- adrenals. Adrenal cholesterol levels returned to near-normal levels in mice treated with ezetimibe, which blocks phytosterol absorption. To determine which plant sterol(s) caused the metabolic changes, we examined the effects of individual plant sterols on cholesterol metabolism in cultured adrenal cells. Addition of stigmasterol, but not sitosterol, inhibited SREBP-2 processing and reduced cholesterol synthesis. Stigmasterol also activated the liver X receptor in a cell-based reporter assay. These data indicate that selected dietary plant sterols disrupt cholesterol homeostasis by affecting two critical regulatory pathways of lipid metabolism.

ATP Binding Cassette Transporter, Subfamily G↗

PubMed2004

[Analysis of T cell subsets and CD3zeta chain expression in myelodysplastic syndrome patients].

Immune mediated suppression of hematopoiesis has been considered as one of the most important mechanisms leading to pancytopenia in myelodysplastic syndromes. This research was aimed at evaluating immune state of the MDS patients, analyzing the peripheral blood T cell subsets and CD3zeta chain expression and searching the possible reasons of hematopoietic disorders in 11 cases of MDS. Peripheral blood mononuclear cells were collected from 11 patients whose diagnosis was confirmed according to the new WHO diagnostic criteria. Flow cytometry was used for the counts of IFNgamma(+)CD4(+) cell (Th1), IL4(+)CD4(+) cell (Th2), IFNgamma(+)CD8(+) cell (Tc1), and IL4(+)CD8(+) cell (Tc2), and for the analysis of expression of CD3zeta chain in T cell subsets. The results showed that CD8(+) cells increased significantly in MDS patients; there was no significant difference between Th1/Th2, Tc1/Tc2 ratios of T cell subsets and normal control; CD3zeta chain, the functional protein in the signal transduction pathway of T cell, was over expressed in the CD8(+) cell. In conclusion, research indicates that abnormal changes of T cell subgroups exist in peripheral blood of MDS patients. Enhancement of CD8(+) cells and over-expression of CD3zeta chain are important features, which suggest that CD8(+) cells play the most critical role in the pathologic process as compared with other T cell subsets. The over active immunity mediated by T cell subset may be one of the major mechanisms resulting in cytopenia in MDS.

Aged↗

PubMed2003

Dexamethasone-induced gene 2 (dig2) is a novel pro-survival stress gene induced rapidly by diverse apoptotic signals.

Glucocorticoid hormones induce apoptosis in lymphoid cells. This process requires de novo RNA/protein synthesis. Here we report the identification and cloning of a novel dexamethasone-induced gene designated dig2. Using Affymetrix oligonucleotide microarray analysis of approximately 10,000 genes and expressed sequence tags, we found that the expression of dig2 mRNA is significantly induced not only in the murine T cell lymphoma lines S49.A2 and WEHI7.2 but also in normal mouse thymocytes following dexamethasone treatment. This result was confirmed by Northern blot analysis. The induction of dig2 mRNA by dexamethasone appears to be mediated through the glucocorticoid receptor as it is blocked in the presence of RU486, a glucocorticoid receptor antagonist. Furthermore, we demonstrated that dig2 is a novel stress response gene, as its mRNA is induced in response to a variety of cellular stressors including thapsigargin, tunicamycin, and heat shock. In addition, the levels of dig2 mRNA were up-regulated after treatment with the apoptosis-inducing chemotherapeutic drug etoposide. Though the function of dig2 is unknown, dig2 appears to have a pro-survival function, as overexpression of dig2 reduces the sensitivity of WEHI7.2 cells to dexamethasone-induced apoptosis.

Adaptor Proteins, Signal Transducing↗

PubMed2003

Packaging of an AAV vector encoding human acid alpha-glucosidase for gene therapy in glycogen storage disease type II with a modified hybrid adenovirus-AAV vector.

We have developed an improved method for packaging adeno-associated virus (AAV) vectors with a replication-defective adenovirus-AAV (Ad-AAV) hybrid virus. The AAV vector encoding human acid alpha-glucosidase (hGAA) was cloned into an E1, polymerase/preterminal protein-deleted adenovirus, such that it is packaged as an Ad vector. Importantly, the Ad-AAV hybrid cannot replicate during AAV vector packaging in 293 cells, because of deletion of polymerase/preterminal protein. The residual Ad-AAV in the AAV vector stock was reduced to <1 infectious particle per 10(10) AAV vector particles. These modifications resulted in approximately 30-fold increased packaging of the AAV vector for the hybrid Ad-AAV vector method as compared with standard transfection-only methods. Similarly improved packaging was demonstrated for pseudotyping the AAV vector as AAV6, and for AAV vector packaging with a second Ad-AAV vector encoding canine glucose-6-phosphatase. Liver-targeted delivery of either the Ad-AAV hybrid or AAV vector particles in acid alpha-glucosidase-knockout (GAA-KO) mice revealed secretion of hGAA with the Ad-AAV vector, and sustained secretion of hGAA with an AAV vector in hGAA-tolerant GAA-KO mice. Further development of hybrid Ad-AAV vectors could offer distinct advantages for gene therapy in glycogen storage diseases.

Adenoviridae↗

PubMed2003

Local anesthetics modulate neuronal calcium signaling through multiple sites of action.

BACKGROUND: Local anesthetics (LAs) are known to inhibit voltage-dependent Na+ channels, as well as K+ and Ca2+ channels, but with lower potency. Since cellular excitability and responsiveness are largely determined by intracellular Ca2+ availability, sites along the Ca2+ signaling pathways may be targets of LAs. This study was aimed to investigate the LA effects on depolarization and receptor-mediated intracellular Ca2+ changes and to examine the role of Na+ and K+ channels in such functional responses. METHODS: Effects of bupivacaine, ropivacaine, mepivacaine, and lidocaine (0.1-2.3 mm) on evoked [Ca2+](i) transients were investigated in neuronal SH-SY5Y cell suspensions using Fura-2 as the intracellular Ca2+ indicator. Potassium chloride (KCl, 100 mm) and carbachol (1 mm) were individually or sequentially applied to evoke increases in intracellular Ca2+. Coapplication of LA and Na+/K+ channel blockers was used to evaluate the role of Na+ and K+ channels in the LA effect on the evoked [Ca2+](i) transients. RESULTS: All four LAs concentration-dependently inhibited both KCl- and carbachol-evoked [Ca2+](i) transients with the potency order bupivacaine > ropivacaine > lidocaine >/= mepivacaine. The carbachol-evoked [Ca2+](i) transients were more sensitive to LAs without than with a KCl prestimulation, whereas the LA-effect on the KCl-evoked [Ca2+](i) transients was not uniformly affected by a carbachol prestimulation. Na+ channel blockade did not alter the evoked [Ca2+](i) transients with or without a LA. In the absence of LA, K+ channel blockade increased the KCl-, but decreased the carbachol-evoked [Ca2+](i) transients. A coapplication of LA and K+ channel blocker resulted in larger inhibition of both KCl- and carbachol-evoked [Ca2+](i) transients than by LA alone. CONCLUSIONS: Different and overlapping sites of action of LAs are involved in inhibiting the KCl- and carbachol-evoked [Ca2+](i) transients, including voltage-dependent Ca2+ channels, a site associated with the caffeine-sensitive Ca2+ store and a possible site associated with the IP(3)-sensitive Ca2+ store, and a site in the muscarinic pathway. K+ channels, but not Na+ channels, seem to modulate the evoked [Ca2+](i) transients, as well as the LA-effects on such responses.

Amides↗

PubMed2003

Isoflurane reduction of carbachol-evoked cytoplasmic calcium transients is dependent on caffeine-sensitive calcium stores.

BACKGROUND: Many muscarinic functions are relevant to anesthesia, and alterations in muscarinic activity affect the anesthetic/analgesic potency of various drugs. Volatile anesthetics have been shown to depress muscarinic receptor function, and inhibition of the muscarinic signaling pathway alters the minimal alveolar anesthetic concentration of inhaled anesthetics. The purpose of this investigation was to determine in a neuronal cell which source of Ca2+ underlying the carbachol-evoked transient increase in cytoplasmic Ca2+ was reduced by isoflurane. METHODS: Experiments were performed at 37 degrees C on continuously perfused monolayers of human neuroblastoma SH-SY5Y cells using Fura-2 as the cytoplasmic Ca2+ indicator. Carbachol (1 mm) was applied to evoke a transient increase in cytoplasmic Ca2+. RESULTS: Isoflurane (1 mm) reduces the carbachol-evoked transient increase in cytoplasmic Ca2+, and this isoflurane action is eliminated when the cells are continuously stimulated with 200 mm KCl or pretreated with 10 mm caffeine or 200 microm ryanodine. CONCLUSIONS: Isoflurane reduction of the carbachol-evoked transient increase in cytoplasmic Ca2+ requires full caffeine-sensitive Ca2+ stores and Ca2+ release from the caffeine-sensitive stores through the ryanodine-sensitive Ca2+ release channels. The results indicate that isoflurane interferes with a muscarinic Ca2+ signaling through a mechanism downstream from the muscarinic receptors.

Caffeine↗

PubMed2003

[Clinical study on treatment of patients with upper digestive tract malignant tumors of middle and late stage with Ginkgo biloba exocarp polysaccharides capsule preparation].

OBJECTIVE: To observe the clinical efficacy of Ginkgo biloba exocarp polysaccharides (GBEP) capsule preparation in treating upper digestive tract malignant tumors of middle and late stage. METHODS: Eighty-six patients of the upper digestive tract malignant tumors were treated with GBEP capsule preparation taken orally. The clinical symptoms and the qualities of life of the patients with single GBEP and combined with operation, radiotherapy or intervention chemotherapy were observed. The tumor size was measured by electronic gastroscope before and after treatment with single GBEP. Objective response rate (RR) of the tumor was calculated. The survival period of patient was observed. The changes of blood routine examination in the patients treated with radiotherapy were observed. RESULTS: GBEP preparation could markedly improve the patients'clinical symptoms. Karnofsky scoring of the patients markedly increased after treatment. There were 2 CR (complete response, 6.3%), 22 PR (partial response, 68.8%)and 5 SD (stable disease, 15.6%) of 32 cases with single GBEP preparation. The survival periods of the 32 cases were markedly prolonged. The preparation could relieve the inhibited hematopietic function and the weight loss due to radiotherapy. CONCLUSION: GBEP capsule preparation has some definite therapeutic effects on upper digestive tract malignant tumors of middle and late stage.

Administration, Oral↗

PubMed2003

[Cloning and bioinformatics of human REV3 gene promoter region and its response to carcinogen N-methyl-N'-nitro-N-nitrosoguanidine].

OBJECTIVE: To understand the up regulatory mechanism of human REV3 gene induced by the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). METHODS: Bioinformatic analysis of human REV3 gene promoter region was based on BLAST alignment, promoter prediction software and recognition of transcriptional factor binding sites. Cloning of human REV3 gene promoter region was performed by nested PCR. Response of human REV3 gene promoter to the chemical carcinogen MNNG was measured by transient transfection assay based on the dual luciferase reporter assay system. RESULT: Bioinformatic analysis showed that human REV3 gene promoter region was located on chromosome 6 PAC clone RP3-415N12, and that the hypothetical promoter region contained promoter sequences, rich CpG islands, and putative recognition sites for several transcriptional factors, including AP-1/c-Jun/c-Fos, AP-2, STAT, CREBP, and NF-kappaB. Reconstructed reporter plasmid pGL3- 2582 was established by inserting 2582 nucleotides from the promoter region into the luciferase reporter vector pGL3-Basic. Transient transfection assay showed the hypothetical REV3 promoter region had promoter function, and it responded to MNNG treatment (P<0.01). CONCLUSION: Human mutator REV3 gene promoter region has been successfully cloned. The response of REV3 promoter region to MNNG suggests that REV3 gene can be regulated at transcriptional level under conditions of genotoxic stress.

Base Sequence↗

PubMed2003

[The research update on cellular immune abnormality in myelodysplastic syndrome--review].

Myelodysplastic syndrome is a group of diseases characterized by abnormal clonal proliferation of hematopoietic cells and pancytopenia with dysplasia. The pathogenesis of MDS includes factors of chromosome aberrations, gene mutations, immune abnormalities, environmental changes, and so on. Now it is commonly accepted that MDS is a multistep process disorder involving more etiologic alterations. Recently more and more investigations indicate that the abnormality of cellular immunity is one of important reasons related to MDS. Some proofs about the abnormal activation of T-cell and the abnormal expressions of cytokines in different stages of immune response in MDS have been documented, meanwhile, numerous clinical studies on immune therapy in MDS provide a great number of evidences to disclose its immune abnormalities.

Cytokines↗