Biomedical subjects

Yu Zheng

Publications and source records attributed to Yu Zheng.

At least 37 records · Page 2Linked to original sources

PubMed2005

[Expression and purification of two kinds of alternative splicing mouse Era].

AIM: To express and purify two alternative splicing mouse Era proteins and detect whether anti-human Era antibody can be used in the study of mouse Era proteins. METHODS: Two fusion protein expression vectors, pMAL-meraW and pMAL-meraS, were constructed, then the MBP-mEra proteins were expressed in E. coli. The target proteins were purified by amylose affinity chromatography. The specificity of rabbit anti-human Era antibody to the proteins was identified by Western blot. RESULTS: The expressed MBP-mEraW and MBP-mEraS proteins constituted approximately 17% and 19% of the total bacterial proteins. The purity of the fused proteins was 67% and 61% respectively after amylose affinity chromatography. Rabbit anti-human Era antibody had high specificity to these two kinds of splicing mouse Era proteins. CONCLUSION: Two fusion mera genes could be expressed in E. coli by using gene recombination technique. The high specificity of rabbit anti-human Era antibody to the two splicing mouse ERA proteins indicates that this antibody can be used to study the function of these two kinds of splicing mouse Era.

Alternative Splicing↗

PubMed2005

[Structure charateristics of mitoxantrone transforsomes].

This study sought to clarify the molecular location and the interaction between mitoxantrone and mitoxantrone transforsomes. The anthraquinone of mitoxantrone, a heterocyclic ring that intercalates in the lipid of bilayer, was determined by UV-spectrophotometry and electron probes scan microscopy. Two aminoethylamino side-chains of the drugs fit to the phosphates of lecithin were determined by 8-value, thus the interaction with lecithin was substantiated. Differential scanning calorimetry confirmed that mitoxantrone has remarkable stabilizing effect on the mitoxantrone transforsomes membrane. The mitoxantrone binds tightly to lecithin. So a high degree of encapsulation efficiency and the sustained-release character of mitoxantrone transforsomes are verified.

Anthraquinones↗

PubMed2005

[Protective effect of tetramethylpyrazine on the respiratory inhibition induced by hypoxia in rats].

OBJECTIVE: To study the protective effect of tetramethylpyrazine (TMP) on the respiratory inhibition induced by hypoxia. METHODS: Forty-four SD rats were used. The hypoxic rat model was established. The effects of TMP on the responses of respiratory activity and life time to hypoxia were observed. The Nissl's staining and immunohistochemical technique were used to investigate the effect of hypoxia on the Nissl's bodies and FOS expression in the brainstem and the antagonistic action of TMP. RESULTS: In contrast to the group of hypoxia, the occurrence of respiratory inhibition was delayed and the life time was prolonged obviously in the rats of hypoxia plus TMP (P<0.01). Compared with the air contronl group, the intensity of the Nissl's staining of the brainstem neurons became weaker in the group of hypoxia, but in the group of hypoxia plus TMP, the Nissl's staining was stronger and the gray degree decreased obviously, compared with the group of hypoxia (P<0.05). FOS positive neurons were induced by hypoxia and mainly existed in the nucleus of solitary tract, area postrema, hypoglossal nucleus, lateral reticular nucleus, inferior olivary nucleus, nucleus raphe pallidus, facial nucleus, trapezoid nucleus, but in the group of hypoxia plus TMP, the level of FOS immunoreactivity decreased remarkably, compared with the group of hypoxia (P<0.05). CONCLUSION: TMP has protective effect on the respiratory inhibition induced by hypoxia and FOS may be involved in the protection.

Animals↗

PubMed2005

[Construction of fusion expression vector of human-derived neurotrophin-6 gene encoding mature peptide and purification of its expressed product].

To get the mature peptide of human-derived neurotrophin-6 (NT-6), NT-6 gene encoding mature peptide was amplified by PCR, using the NT-6 cDNA that had been cloned as templet. The gene encoding mature peptide of NT-6 gene was cloned into pGEX1-lambdaT plasmid to construct the fusion expression vector. Expression of fusion protein in Escherichia coli was defected after induction by isopropyl beta-D-thiogalactoside(IPTG). The mature peptide of NT-6 was collected with GST fusion protein purifying kit. It was shown that a fragment of 460bp was gained by PCR. With the techniques of double-cleave and electrophoresis, the recombinant vector was identified as pGEX1-NT-6. The recombinant vector pGEX1-NT-6 transformed Escherichia coli expressed fusion protein of 41KD after induction by IPTG. Cleaved by thrombin, the mature peptide of NT-6 was obtained; its molecular weight was about 15KD. The cloning and expression of human-derived NT-6 gene encoding mature protein has provided a basis for further studies on the function and clinical application of NT-6.

Escherichia coli↗

PubMed2005

[Pharmacokinetic study of intraperitoneal chemotherapy with HCPT].

OBJECTIVE: To study the pharmacokinetic of 10-Hydroxycamptothecin HCPT by intraperitoneal administration. METHOD: Six dogs were given HCPT by intraperitoneal perfusion: HCPT 2 mg x kg(-1), dissolved in 300 mL NS. During the course of experiments, peritoneal fluids and blood were sampled using a standardized protocol. The concentration of HCPT in all samples was determined by high performance liquid chromatography (HPLC). RESULT: The area under the curve (AUC) of peritoneal fluids was significantly highly as compared to the AUC of femoral vein and portal vein (P < 0.001). CONCLUSION: These experiments demonstrate that intraperitoneal chemotherapy has significant effect on the pharmacokinetics of IP route of HCPT administration. This method should be a more reasonable chemotherapy for the prevention of recurrence and liver metastasis of gastric cancer, colon cancer and ovary cancer after radical resection.

Animals↗

PubMed2004

[Effect of stimulation of the facial nucleus on discharge of respiratory neurons in the pre-Bözinger complex and its neurotransmitter mechanism in rats].

The experiments were carried out on adult Sprague-Dawley rats. We investigated the discharge response of respiratory neurons (RNs) in the pre-Bözinger complex (PBC) to electrical stimulation of the facial nucleus in which the motor neurons were retrogradely degenerated and the antagonistic effects of microiontophoresis of CNQX, bicuculline (BIC), strychnine (Stry) and atropine on the discharge responses of the neurons. In 12 rats with retrograde degeneration of the facial motor neurons, 116 RNs in the PBC ipsilateral to the facial nerve sectioned were extracellularly recorded. The response of pre-inspiratory (Pre-I) (24 / 26) and inspiratory (I) (30 / 35) neurons to the electrical stimulation of the facial nucleus was mainly excitatory, and the response of expiratory (E) (20 / 22) and inspiratory-expiratory phase-spanning (I-E) (28 / 33) neurons was mainly inhibitory. CNQX partially or completely block the excitatory effect of the stimulation on Pre-I (18 / 24) and I (23 / 27) neurons. Stry could partially or completely block the immediate transient inhibition on Pre-I (12 / 18) and I (14 / 23) neurons and the inhibitory effect on I-E (20 / 28) and E (9 / 16) neurons induced by the stimulation. BIC partially or completely blocked the inhibitory effect on I-E (22 / 25) and E (9 / 9) neurons induced by the stimulation. Atropine did not have obvious influence on the response of RNs to the stimulation. These results suggest that non-motoneurons in the facial nucleus may participate in the modulation of respiration by affecting the activities of RNs in the PBC and that Glu, GABA and Gly serve as neurotransmitters or modulators to regulate the activities of the RNs in the PBC and hence the rhythmic respiratory movement.

Animals↗

PubMed2004

Identification of genes with fast-evolving regions in microbial genomes.

Complete sequences of multiple strains of the same microbial species provide an invaluable source for studying the evolutionary dynamics between orthologous genes over a relatively short time scale. Usually the intensity of the selection pressure is inferred from a comparison between the nonsynonymous substitution rate and the synonymous substitution rate. In this paper, we propose an alternative method for detecting genes with one or more fast-evolving regions from pairwise comparisons of orthologous genes. Our method looks for regions with overrepresented nonsynonymous mutations along the alignment, and requires a higher nonsynonymous evolution rate in those regions than the neutral evolution rate. It identifies gene targets under intensive selection pressure that are not detected from the conventional rate comparison analysis. For those identified genes with known annotations, most of them have a clear role in processes such as bacterial defense and host-pathogen interactions. Gene sets reported from our method provide a measure of the phenotypic divergence between two closely related genomes.

Amino Acid Sequence↗

PubMed2004

Projections from facial nucleus interneurons to the respiratory groups of brainstem in the rat.

Projections of the interneurons of the facial nucleus to respiration-related areas in the brainstem of the rat were revealed by unilateral, iontophorectic injection of the anterograde neuronal tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), into the facial nucleus after motor neurons degeneration had been induced by axotomy of the facial nerve. Anterogradely labeled fibers and terminals were found bilaterally in the nucleus tractus solitarius, nucleus ambiguous and ventrolateral reticular formation in the medulla oblongata and ipsilaterally in the nucleus parabrachialis and nucleus Kolliker-Fuse in the pons. These results revealed that the interneurons in the facial nucleus have widespread projections to the respiratory groups in the brainstem, and suggest that the facial nucleus is involved not only in the control of muscles for facial expression but also in the regulation of functional respiratory activity.

Animals↗

PubMed2004

Possible involvement of the facial nucleus in regulation of respiration in rats.

The facial nucleus (FN) has been known as a motor nucleus to control the activity of the facial skeletal muscles by its efferent somatic motoneurons. Much less, however, is known about the non-motor control functions of its interneurons. The present study was designed to investigate if the interneurons of the FN participate in controlling rhythmic respiration in the sodium thiopental-anesthetized and vagotomized Sprague-Dawley rats with facial motoneurons retrogradely degenerated with techniques of electrical and chemical stimulation of the FN and extracellular recording of discharge of neurons in the FN. Single pulse stimulation (75-100 microA, 0.2 ms) of the FN during inspiration caused a transient restrain in phrenic discharge. Short train stimulation (75-100 microA, 0.2 ms, 100 Hz, 3-5 pulses) delivered during the early- or mid-term of inspiration augmented the inspiratory duration, but switched the inspiration off when delivered during the later stage of inspiration. Short train stimulation delivered during expiration prolonged the expiratory duration. Continuous stimulation could inhibit the inspiration. Microinjection of kainic acid into the FN caused an augmentation in inspiratory duration and amplitude and in expiratory duration. These data indicate that the interneurons of the FN might participate in the modulation of respiration. Different discharge patterns of interneurons in the FN, interestingly some respiratory related patterns, were observed, which provide a possible structural basis for the role of the FN in respiratory regulation.

Action Potentials↗

PubMed2004

[Tutin-induced epileptiform discharge of CA1 pyramidal cells in rat hippocampal slices].

Previous studies showed that a mixture, Coriaria Lactone (CL), extracted from a traditional Chinese herb Loranthus Parasiticus Mer, had a great excitatory influence on the nervous system, resulting in seizure. But what component in CL causes seizure is unclear. Tutin is a pure chemical component derived from CL. The present experiments were carried out to test if tutin has any epileptogenic action and to preliminarily study the mechanism underlying that action in vitro. The electrical activity of CA1 pyramidal cells, population spikes (PS), evoked by stimulation of the Schaffer collaterals in rat hippocampal slices was recorded extracellularly. The effects of tutin on the PS and the antagonistic actions of CNQX and AP-5 on the tutin-induced effects were investigated. The results are as follows. (1) Superfusion with 40, 30 and 20 microg/ml tutin caused significant increase in the amplitude and number of PS waves evoked by stimulating the Schaffer collaterals. Thirty minutes after superfusion of tutin, the amplitude of the first wave of the PSs was increased by (388.7+/-0.1)%, (317.2+/-19.1)% and (180.9+/-11.6)% in each of the above three groups, respectively, compared with the control (for each group, n=5, P<0.05). (2) With increase in amplitude, the PS number was increased to 4~11 waves from a single wave in the control and manifested multiple epileptiform discharges 30 min superfusion with tutin. (3) Spontaneous epileptiform discharges of CA1 pyramidal cells were obtained in 9 out of 34 cases after tutin superfusion. (4) The tutin-induced multiple epileptiform discharges of the CA1 pyramidal cells were completely blocked by CNQX, in aspects of both amplitude and number of the PS. Following the application of AP-5, the increase in the wave number of the tutin-induced epileptiform discharges was inhibited but the increase in the amplitude of the discharges was not significantly affected. These results indicate that tutin can induce typical multiple epileptiform discharges of CA1 pyramidal cells in rat hippocampal slices and might be used as an efficient epileptogenic agent, and that the excitable glutamate receptors, especially the non-NMDA receptors, may participate in the genesis of tutin-induced epileptiform discharges.

Animals↗

PubMed2004

[Integrins mediate the increase of concentration of intracellular free calcium in mouse eggs].

For studying the effect of integrin on the [Ca(2+)](i) of mouse eggs and its transmembrane signaling mechanism, zona-free mouse eggs were loaded with calcium probe Fluo-3/AM and the intensity of fluorescence of the eggs treated with different factors was measured through laser confocal microscopy. The results showed that the [Ca(2+)](i) of zona-free mouse eggs was increased when the eggs were treated with RGD peptide, fibronectin (Fn) and anti-mouse integrin subunit alpha(6) and beta(1) monoclonal antibodies, respectively. The [Ca(2+)](i) of the mouse eggs was also increased when the eggs were placed in calcium-free medium and treated with RGD peptide or Fn. The changes in the mouse egg [Ca(2+)](i) caused by RGD and Fn were similar to those caused by sperm. However, the concentration of Ca(2+) of the zona-free mouse eggs pretreated with tyrosine kinase inhibitor was not increased when the eggs were treated in the same way, and, neither was the intracellular calcium increased in those eggs pretreated with PKC inhibitor when the eggs were treated with RGD peptide. It is therefore suggested that the occupancy of integrins on the membrane of mouse eggs by their ligands mediates the release of Ca(2+) and then the increase in the [Ca(2+)](i) of eggs, which is one of the early events of egg activation. The tyrosine kinase signaling pathway and PKC are involved in this process as well.

Animals↗

PubMed2004

Catheterization-associated complications of intraperitoneal chemotherapy in advanced gastric cancer.

AIM: To assess the catheterization-associated complications during intraperitoneal chemotherapy (IPCT) for advanced gastric cancer. METHODS: From 1998 to 2002, 80 patients with advanced gastric cancer received a total of 320 courses of IPCT using a large bore central venous catheter and associated complications were analyzed. RESULTS: Catheterization-associated complications occurred in 11 of the 80 patients (13.8%), including abdominal pain caused by catheter in 2 cases (0.63%), insertion failure in 2 cases (0.63%), bowel perforation in 1 case (0.31%) and abdominal pain during chemotherapy in 6 cases (1.88%). No serious complications required surgical intervention. CONCLUSION: IPCT using central venous catheters can be performed safely and simply without severe associated complications.

Adult↗

PubMed2004

Segmentally variable genes: a new perspective on adaptation.

Genomic sequence variation is the hallmark of life and is key to understanding diversity and adaptation among the numerous microorganisms on earth. Analysis of the sequenced microbial genomes suggests that genes are evolving at many different rates. We have attempted to derive a new classification of genes into three broad categories: lineage-specific genes that evolve rapidly and appear unique to individual species or strains; highly conserved genes that frequently perform housekeeping functions; and partially variable genes that contain highly variable regions, at least 70 amino acids long, interspersed among well-conserved regions. The latter we term segmentally variable genes (SVGs), and we suggest that they are especially interesting targets for biochemical studies. Among these genes are ones necessary to deal with the environment, including genes involved in host-pathogen interactions, defense mechanisms, and intracellular responses to internal and environmental changes. For the most part, the detailed function of these variable regions remains unknown. We propose that they are likely to perform important binding functions responsible for protein-protein, protein-nucleic acid, or protein-small molecule interactions. Discerning their function and identifying their binding partners may offer biologists new insights into the basic mechanisms of adaptation, context-dependent evolution, and the interaction between microbes and their environment.

Acclimatization↗

PubMed2004

Sequence-specific assignments of methyl groups in high-molecular weight proteins.

A new 3D multiple-quantum (H)CCmHm-TOCSY experiment is proposed to assign methyl resonances in high-molecular weight proteins, on the basis of spectral patterns and prior backbone assignments. The favorable relaxation properties of the multiple-quantum coherences and the slow decays of in-phase methyl 13C magnetizations optimize performance of the proposed experiment for application to large proteins. The experiment has been demonstrated on an acyl carrier protein synthase (trimer, 42 kDa, overall correlation time of 26 ns) at 25 degrees C, and 63 out of 67 nonmethionine methyl groups have been assigned.

Carbon Isotopes↗

PubMed2004

[Effect of sex hormones on heme oxygenase expression in rat ventral prostate].

Heme oxygenase (HO) is a rate-limiting enzyme for endogenous carbon monoxide (CO) production. Recently it has been suggested that endogenous CO plays an important role in regulating smooth muscle tone. The development of bladder outlet obstruction in men with benign prostates hyperplasia was shown to be related to the prostates smooth muscle tone, but it was not clear whether endogenous HO/CO system mediates prostates smooth muscle activity. To investigate the influence of sex hormone on the expression of heme oxygenase (HO) gene in rat ventral prostate, we created the model of castrated male rats to test the mRNA levels of HO-1 and HO-2 by RT-PCR, and used immunohistochemical staining procedures with image analytic technical system to confirm the effects of exogenous androgen and estrogen on the expression of HO-1 and HO-2 protein in rat ventral prostate. The results showed that two isoforms of HO were present in rat ventral prostate. The epithelial cells of acini and fibromuscular stroma of the rat prostate displayed HO-1 immunoreactivity, whereas HO-2 immunostaining was only examined to be in the acinar cells. Both at protein and transcript levels, HO-1 in castrated group was markedly decreased compared with the normal control group (p<0.01). In groups of exogenous administration of androgen and estrogen HO-1 was much higher than that in the control groups (p<0.01). However, estrogen increased HO-1 protein level in prostate stroma, while the levels of HO-2 did not give any evidence of change among all groups (p>0.05). These findings suggest that expression of HO-1 gene is induced by sex hormones, in contrast, there is no change in HO-2 expression. We speculate that CO-HO system is possibly involved in the pathologic processes of prostates abnormal proliferation induced by sex hormones and that CO derived from HO-1 may play an important role in the regulation of smooth muscle activity in rat prostate.

Animals↗

PubMed2004

[Effect of arginine vasopressin on membrane potential of dorsal root ganglion neurons in rats].

The effect of arginine vasopressin (AVP) on membrane potential of neurons from dorsal root ganglion (DRG) was examined in the rat by means of intracellular recording technique. The results showed that (1) AVP induced hyperpolarization in the membrane of most DRG neurons. (2) The membrane conductance of the DRG neurons increased by 19.32% following application of AVP (p<0.05). (3) Perfusion with balance sodium solution (BSS) containing Cd(2+) (blocker of Ca(2+) channel) instead of Na+ failed to affect the AVP-induced membrane hyperpolarization of the DRG neurons (p> 0.05). After perfusion with BSS containing tetraethylammonium (TEA), however, the extent of AVP-induced hyperpolarization was reduced (p<0.05). (4) The AVP-induced hyperpolarization of the neurons was blocked by the antagonist of AVP V(1) receptors. The results demonstrate that AVP induces hyperpolarization of most DRG neurons, which might be caused by K(+) outflow mediated by AVP V(1) receptors in the membrane of the neurons.

Animals↗

PubMed2004

Whole-genome annotation by using evidence integration in functional-linkage networks.

The advent of high-throughput biology has catalyzed a remarkable improvement in our ability to identify new genes. A large fraction of newly discovered genes have an unknown functional role, particularly when they are specific to a particular lineage or organism. These genes, currently labeled "hypothetical," might support important biological cell functions and could potentially serve as targets for medical, diagnostic, or pharmacogenomic studies. An important challenge to the scientific community is to associate these newly predicted genes with a biological function that can be validated by experimental screens. In the absence of sequence or structural homology to known genes, we must rely on advanced biotechnological methods, such as DNA chips and protein-protein interaction screens as well as computational techniques to assign putative functions to these genes. In this article, we propose an effective methodology for combining biological evidence obtained in several high-throughput experimental screens and integrating this evidence in a way that provides consistent functional assignments to hypothetical genes. We use the visualization method of propagation diagrams to illustrate the flow of functional evidence that supports the functional assignments produced by the algorithm. Our results contain a number of predictions and furnish strong evidence that integration of functional information is indeed a promising direction for improving the accuracy and robustness of functional genomics.

Chromosome Mapping↗

PubMed2004

Preconditioning with prolonged oxygen exposure induces ischemic tolerance in the brain via oxygen free radical formation.

PURPOSE: To determine if 100% oxygen (O2) inhalation induces ischemic tolerance to focal cerebral ischemia and if the effect is induced via O2 free radical formation. METHODS: Experiment 1: 36 rats were randomly assigned to four groups (n = 9 each): Group A, control rats inhaled air for 24 hr; Groups B, C and D animals inhaled 100% O2 for six hours, 12 hr and 24 hr respectively. Experiment 2: 32 rats were randomly assigned to four groups (n = 8 each): Groups E and F rats received normal saline (5 mL.kg(-1) intraperitoneally) and then inhaled air (Group E) or 100% O2 (Group F) for 24 hr; Groups G and H animals received 10% dimethylthiourea (500 mg.kg(-1) intraperitoneally) and then inhaled 100% O2 (Group G) or air (Group H) for 24 hr. Twenty-four hours after the treatments, the right middle cerebral artery was occluded in all rats for 120 min. The neurologic deficit scores (NDS) and brain infarct volumes were evaluated at 24 hr after reperfusion. RESULTS: Experiment 1: the infarct volume and NDS of Group D were smaller than in controls (P = 0.004 and 0.042 respectively). The infarct volume was reduced by 47% in Group D. There was no statistical difference among Groups A, B and C. Experiment 2: the infarct volume and NDS in Group F were less than in controls (Group E; P = 0.001 and 0.036 respectively). The infarct volume was reduced by 60% in Group F. There was no difference among Groups E, G and H. CONCLUSION: Our study demonstrates that preconditioning with 100% O2 for 24 hr can induce ischemic tolerance via formation of O2 free radicals in transient focal cerebral ischemia in rats.

Animals↗