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Biomedical subjects

Jun Yu

Publications and source records attributed to Jun Yu.

At least 109 records · Page 6Linked to original sources
PubMed2005

Correlation of cell apoptosis with brain edema and elevated intracranial pressure in traumatic brain injury.

OBJECTIVE: To study the correlation between brain edema, elevated intracranial pressure (ICP) and cell apoptosis in traumatic brain injury (TBI). METHODS: In this study, totally 42 rabbits in 7 groups were studied. Six of the animals were identified as a control group, and the remaining 36 animals were equally divided into 6 TBI groups. TBI models were produced by the modified method of Feeney. After the impact, ICP of each subject was recorded continuously by an ICP monitor until the animal was sacrificed at scheduled time. The apoptotic brain cells were detected by an terminal deoxynucleotide-transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay. Cerebral water content (CWC) was measured with a drying method and calculated according to the Elliott formula. Then, an analysis was conducted to determine the correlation between the count of apoptotic cells and the clinical pathological changes of the brain. RESULTS: Apoptotic cell count began to increase 2 h after the impact, and reached its maximum about 3 days after the impact. The peak value of CWC and ICP appeared 1 day and 3 days after the impact, respectively. Apoptotic cell count had a positive correlation with CWC and ICP. CONCLUSIONS: In TBI, occurrence of brain edema and ICP increase might lead to apoptosis of brain cells. Any therapy which can relieve brain edema and/or decrease ICP would be able to reduce neuron apoptosis, thereby to attenuate the secondary brain damage.

Animals↗
PubMed2005

Cystadenocarcinoma of the liver: a case report.

BACKGROUND: Biliary cystadenocarcinoma as a very rare hepatic neoplasm may be difficult to distinguish from simple hepatic cysts, especially in the unilocular form. Although diagnosis of cystadenocarcinoma during open hepatic surgery demands a complete surgical resection, few reports described the correct approach to such lesions revealed by laparoscopic approach. Five cases of incidental cystadenocarcinoma after laparoscopic surgery for hepatic cystic lesions were presented with discussion of diagnostic and management implications. METHODS: Clinical records of 5 patients who had undergone operation and histological examination at our hospital from 1993 to 2002 were analyzed retrospectively. RESULTS: In all patients who received liver lobectomy, primary hepatic cystadenocarcinoma was diagnosed. Primary biliary cystic neoplasm was difficult to diagnose and the management of both benign and malignant tumors was similar in the 5 patients. CONCLUSIONS: Cystadenocarcinoma is often difficult to diagnose because its clinical manifestations are similar to those of hepatic cysts and other cystic lesions. Imagining examination is helpful in evaluating the disease. Complete excision of cystadenocarcinoma with a wide margin is the best treatment.

Cystadenocarcinoma↗
PubMed2005

[Appropriate application of statistical analysis method in medical science and technology articles].

OBJECTIVE: To introduce the appropriate application of statistical analysis method in medical science and technology articles. METHODS: Explained the correct application of statistical theories in statistical package, statistical analysis methods and test criterion which compose the basic statistical content in an article. RESULTS: If the distribution of numerical variable is normal, mean and standard deviance can be used to describe this variable. In the same way, t test and analysis of variance (ANOVA) can be used to test the difference of mean in each group. If it is not normal, median and range can be used to describe the variable and rank sum test can be used to test the difference of distribution in each group. Categorical variable can be described by rate, proportion and ratio. There are chi-square test, fisher's exact test and rank sum test to test the difference of rates. CONCLUSION: It is the key of choosing rational statistical methods to distinguish the type of design and variable.

Analysis of Variance↗
PubMed2004

Inhibition of gastric cancer-associated angiogenesis by antisense COX-2 transfectants.

We characterized the effects of selective Cox-2 inhibition on the angiogenesis gastric cancer cell line SGC7901 by stable transfection of antisense Cox-2 cDNA (Cox-2-AS) or pharmacological inhibition by selective cox-2 inhibitor (NS398). The conditioned media obtained from SGC7901 treated with Cox-2-AS or NS398 suppressed the proliferation, migration and tube formation of human umbilical vein endothelial cells. Moreover, both treatments inhibited in vivo angiogenesis. These inhibitions could be partially reversed by the addition of PGE2. Our findings support that selective inhibition of Cox-2 alone plays an instrumental role on gastric cancer associated angiogenesis.

Cyclooxygenase 2↗
PubMed2004

Endothelial-specific expression of caveolin-1 impairs microvascular permeability and angiogenesis.

The functions of caveolae and/or caveolins in intact animals are beginning to be explored. Here, by using endothelial cell-specific transgenesis of the caveolin-1 (Cav-1) gene in mice, we show the critical role of Cav-1 in several postnatal vascular paradigms. First, increasing levels of Cav-1 do not increase caveolae number in the endothelium in vivo. Second, despite a lack of quantitative changes in organelle number, endothelial-specific expression of Cav-1 impairs endothelial nitric oxide synthase activation, endothelial barrier function, and angiogenic responses to exogenous VEGF and tissue ischemia. In addition, VEGF-mediated phosphorylation of Akt and its substrate, endothelial nitric oxide synthase, were significantly reduced in VEGF-treated Cav-1 transgenic mice, compared with WT littermates. The inhibitory effect of Cav-1 expression on the Akt-endothelial nitric oxide synthase pathway was specific because VEGF-stimulated phosphorylation of mitogen-activated protein kinase (ERK1/2) was elevated in the Cav-1 transgenics, compared with littermates. These data strongly support the idea that, in vivo, Cav-1 may modulate signaling pathways independent of its essential role in caveolae biogenesis.

Animals↗
PubMed2004

A draft sequence for the genome of the domesticated silkworm (Bombyx mori).

We report a draft sequence for the genome of the domesticated silkworm (Bombyx mori), covering 90.9% of all known silkworm genes. Our estimated gene count is 18,510, which exceeds the 13,379 genes reported for Drosophila melanogaster. Comparative analyses to fruitfly, mosquito, spider, and butterfly reveal both similarities and differences in gene content.

Algorithms↗
PubMed2004

The analysis of large-scale gene expression correlated to the phase changes of the migratory locust.

The migratory locust is one of the most notorious agricultural pests that undergo a well known reversible, density-dependent phase transition from the solitary to the gregarious. To demonstrate the underlying molecular mechanisms of the phase change, we generated 76,012 ESTs from the whole body and dissected organs in the two phases. Comparing 12,161 unigene clusters, we identified 532 genes as phase-related (P < 0.01). Comprehensive assessment of the phase-related expression revealed that, whereas most of the genes in various categories from hind legs and the midgut are down-regulated in the gregarious phase, several gene classes in the head are impressively up-regulated, including those with peptidase, receptor, and oxygen-binding activities and those related to development, cell growth, and responses to external stimuli. Among them, a superfamily of proteins, the JHPH super-family, which includes juvenile hormone-binding protein, hexamerins, prophenoloxidase, and hemocyanins, were highly expressed in the heads of the gregarious hoppers and hind legs of the solitary hoppers. Quantitative PCR experiments confirmed in part the EST results. These differentially regulated genes have strong functional implications that numerous molecular activities are involved in phase plasticity. This study provides ample molecular markers and genomic information on hemimetabolous insects and insights into the genetic and molecular mechanisms of phase changes in locusts.

Animals↗
PubMed2004

Tissue-specific contributions of pneumococcal virulence factors to pathogenesis.

We assessed the ability of Streptococcus pneumoniae mutants deficient in either choline binding protein A (CbpA), pneumolysin (Pln), pyruvate oxidase (SpxB), autolysin (LytA), pneumococcal surface protein A, or neuraminidase A (NanA) to replicate in distinct anatomical sites and translocate from one site to the next. Intranasal, intratracheal, and intravenous models of disease were assessed in 4-week-old BALB/cJ mice by quantitation of bacterial titers in the relevant organs. Mice were also observed by use of real-time bioluminescent imaging (BLI). BLI allowed visualization of the bacteria in sites not tested by sampling. All mutants were created in D39 Xen7, a fully virulent derivative of capsular type 2 strain D39 that contains an optimized luxABCDE cassette. NanA, SpxB, and, to a lesser extent, CbpA contributed to prolonged nasopharyngeal colonization, whereas CbpA and NanA contributed to the transition to the lower respiratory tract. Once lung infection was established, Pln, SpxB, and LytA contributed to bacterial replication in the lungs and translocation to the bloodstream. In the bloodstream, only Pln and LytA were required for high-titer replication, whereas CbpA was required for invasion of the cerebrospinal fluid. We conclude that transitions between body sites require virulence determinants distinct from those involved in organ-specific replication.

Animals↗
PubMed2004

[The possible causes of central pontine myelinolysis after liver transplantation].

OBJECTIVE: To sum up the clinical characteristics of patients with central pontine myelinolysis (CPM) after orthotopic liver transplantation (OLT) and to document the possible causes on CPM. METHODS: 142 patients' data with OLT between January 1999 to May 2003 were analyzed retrospectively. The following risk factors during preoperation were analyzed between patients with and without CPM: primary liver disease, preoperative serum sodium level, magnesium level and plasma osmolality, fluctuation degree of serum sodium concentration, and immunosuppressive drugs level etc. RESULTS: A total of 13 (9.2%) neurologic symptoms appeared in 142 patients post operation, including 5 cases (3.5%) with CPM and 8 cases (5.6%) with cerebral hemorrhage or infarct. 2 patients who developed CPM after OLT had hyponatremia history before operation (serum sodium <130 mmol/L), and the mean serum sodium level was (130.6 +/- 5.54) mmol/L. The serum sodium level was significantly lower in CPM than that of patients without neurologic complication or with cerebral hemorrhage/infarct (P <0.05). The rises of serum sodium perioperative 48 h after OLT in patients with CPM was significantly greater than that in patients with cerebral hemorrhage/infarct or no neurologic complication (19.5 +/- 6.54) mmol/L, (10.1 +/- 6.43) mmol/L, (4.5 +/- 4.34) mmol/L, respectively, (P < 0.05). Plasma osmolality increased greatly postoperatively in patients with CPM. Hypomagnesemia was noted in all patients perioperatively, but there was not significant difference among groups. The duration of operation in CPM was longer than in others (492 +/- 190.05) min (P <0.05). Cyclosporin A (CsA) levels were normal in all patients, but there was significant difference between patients with and without neurologic complication (P <0.05). CONCLUSIONS: CPM may be more prevalent following liver transplantation. Although the diagnosis of CPM after OLT can be made by complete neurologic evaluation including magnetic resonance imaging (MRI) of the head, the mortality is still very high. The occurrence of CPM may be associated with hyponatremia, rapid rise of serum sodium concentration, postoperative increase of plasma osmolality, the duration of operation and high CsA levels.

Adult↗
PubMed2004

Possible causes of central pontine myelinolysis after liver transplantation.

AIM: To sum up the clinical characteristics of patients with central pontine myelinolysis (CPM) after orthotopic liver transplantation (OLT) and to document the possible causes of CPM. METHODS: Data of 142 patients undergoing OLT between January 1999 to May 2003 were analyzed retrospectively. Following risk factors during perioperation were analyzed in patients with and without CPM: primary liver disease, preoperative serum sodium level, magnesium level and plasma osmolality, fluctuation degree of serum sodium concentration, and immunosuppressive drug level, etc. RESULTS: A total of 13 (9.2%) neurologic symptoms appeared in 142 patients post-operation including 5 cases (3.5%) with CPM and 8 cases (5.6%) with cerebral hemorrhage or infarct. Two patients developing CPM after OLT had a hyponatremia history before operation (serum sodium<130 mmol/L), their mean serum sodium level was 130.6 +/- 5.54 mmol/L. The serum sodium level was significantly lower in CPM patients than in patients without neurologic complications or with cerebral hemorrhage/infarct (P<0.05). The increase in serum sodiumduring perioperative 48 h after OLT in patients with CPM was significantly greater than that in patients with cerebral hemorrhage/infarct but without neurologic complications (19.5 +/- 6.54 mmol/L, 10.1 +/- 6.43 mmol/L, 4.5 +/- 4.34 mmol/L, respectively, P<0.05). Plasma osmolality was greatly increased postoperation in patients with CPM. Hypomagnesemia was noted in all patients perioperation, but there were no significant differences between groups. The duration of operation on patients with CPM was longer than that on others (492 +/- 190.05 min, P<0.05). Cyclosporin A (CsA) levels were normal in all patients, but there were significant differences between patients with or without neurologic complications (P<0.05). CONCLUSION: CPM may be more prevalent following liver transplantation. Although the diagnosis of CPM after OLT can be made by overall neurologic evaluations including magnetic resonance imaging (MRI) of the head, the mortality is still very high. The occurance of CPM may be associated with such factors as hyponatremia, rapid rise of serum sodium concentration, plasma osmolality increase postoperation, the duration of operation, and high CsA levels.

Adult↗
PubMed2004

Detailed comparison between the wheat chromosome group 7 short arms and the rice chromosome arms 6S and 8L with special reference to genes involved in starch biosynthesis.

Rice bacterial artificial chromosome (BAC) clones have been identified that contain sequences orthologous to each EST localized to wheat chromosome 7AS deletion stocks by Southern blot hybridization. This information has been used to relate the DNA sequence included in each wheat deletion stock to a complement of rice BACs. A virtual contig was used that covered 90 cM (21 Mb) of DNA sequence (with a gap for the 6S/8L junction). Comparison of the positions of orthologous genes on the rice virtual contig and on wheat chromosome 7AS showed that there was an unexpectedly low level of synteny (31.4%) and a high level of chromosome rearrangements (68.6%). The non-syntenous loci were of two classes: wheat and rice genes found at different locations in the genome (32.6%), and ESTs in wheat not present in rice (36.0%). Four starch synthetic genes, GBSSI, SSI, SSIIa and DBEI, were located at similar positions on wheat chromosome 7AS and the virtual rice contig covering wheat chromosome 7AS. A preliminary comparison between the short arms of chromosome 7A and 7D in wheat showed that both chromosomes had a similar level of sequence synteny with rice. Therefore, there appears to be considerable variation in gene order between wheat chromosome 7S and rice chromosome 6S and 8L.

Chromosomes, Artificial, Bacterial↗
PubMed2004

Bimodal effects of MK-801 on locomotion and stereotypy in C57BL/6 mice.

RATIONALE: Systemic injection of the non-competitive NMDA (N-methyl-D-aspartate) receptor antagonist MK-801 (dizocilpine maleate) causes both increased locomotion in rodents and various stereotypic behaviors that are proposed to model certain aspects of schizophrenic symptoms in humans. OBJECTIVES: This study presents a comprehensive characterization of the bimodal effects of MK-801 on locomotion and stereotypy in the C57BL/6 mouse strain, a strain commonly used for genetically modified mice. RESULTS: We found that it is important to analyze both locomotion and stereotypy in parallel, as MK-801-induced stereotypy results in abnormal movements that are recorded as locomotion by automated beam detection systems. Furthermore, it is important to analyze the bimodal effects of MK-801 over an extended time span, rather than the commonly used narrower time window, as at higher doses (e.g., above 0.3 mg/kg) the hyperlocomotion phase develops only after the stereotypic phase subsides. We also observed that the apparent dose-response curve is very sensitive to the particular time window chosen for analysis because MK-801 affects both the time course and maximum value of stimulated locomotion. We show that analyzing the absolute peak value of locomotion induced for each animal, rather than group-averaged time courses, provides a measure that is sensitive over a wider range of MK-801 doses. Interestingly, MK-801 even at a very low dose of 0.02 mg/kg suppressed rather than enhanced rearing behavior, differing in this regard from amphetamine. CONCLUSIONS: The non-competitive NMDA receptor antagonist MK-801 induces a complex pattern of behavioral modification in mice with respect to both the time course and the dose-response relationship of behavioral changes. The results of this study provide a foundation and frame of reference for the growing interest in studying MK-801-induced behavior in mice.

Animals↗
PubMed2004

Complete genome sequence of Yersinia pestis strain 91001, an isolate avirulent to humans.

Genomics provides an unprecedented opportunity to probe in minute detail into the genomes of the world's most deadly pathogenic bacteria- Yersinia pestis. Here we report the complete genome sequence of Y. pestis strain 91001, a human-avirulent strain isolated from the rodent Brandt's vole-Microtus brandti. The genome of strain 91001 consists of one chromosome and four plasmids (pPCP1, pCD1, pMT1 and pCRY). The 9609-bp pPCP1 plasmid of strain 91001 is almost identical to the counterparts from reference strains (CO92 and KIM). There are 98 genes in the 70,159-bp range of plasmid pCD1. The 106,642-bp plasmid pMT1 has slightly different architecture compared with the reference ones. pCRY is a novel plasmid discovered in this work. It is 21,742 bp long and harbors a cryptic type IV secretory system. The chromosome of 91001 is 4,595,065 bp in length. Among the 4037 predicted genes, 141 are possible pseudo-genes. Due to the rearrangements mediated by insertion elements, the structure of the 91001 chromosome shows dramatic differences compared with CO92 and KIM. Based on the analysis of plasmids and chromosome architectures, pseudogene distribution, nitrate reduction negative mechanism and gene comparison, we conclude that strain 91001 and other strains isolated from M. brandti might have evolved from ancestral Y. pestis in a different lineage. The large genome fragment deletions in the 91001 chromosome and some pseudogenes may contribute to its unique nonpathogenicity to humans and host-specificity.

Carbohydrate Metabolism↗
PubMed2004

[Vasonatrin peptide attenuates the enhancement of electrically-induced intracellular calcium transient by isoproterenol in rat cardiac myocytes].

The purpose of this study was to investigate the effects of vasonatrin peptide (VNP) on electrically-induced intracellular calcium ([Ca(2+)](i)) transient and mechanism of the effects in the cardiac myocytes. The [Ca(2+)](i) transient was measured with a fluoremetric method. The effects of HS-142-1, 8-Br-cGMP and methylene blue (MB) on [Ca(2+)](i) transient in cardiac myocytes were also determined. Isoproterenol (Iso) at 10(-10)~10(-6) mol/L augmented electrically-induced [Ca(2+)](i) transient dose-dependently, which was (13+/-8)% (P>0.05), (26+/-13)% (P< 0.05), (66+/-10)% (P<0.01), (150+/-10)% (P<0.01) and (300+/-25)% (P<0.01), respectively. These effects were blocked by an beta-adrenergic bloker propranolol (10(-6) mol/L). The effect of Iso (10(-8) mol/L) on [Ca(2+)](i) transient was attenuated in a dose-dependent manner by VNP at 10(-10)~10(-6) mol/L, which was (99+/-3)% (P>0.05), (96+/-2)% (P<0.05), (84+/-6)% (P<0.01), (66+/-3)% (P<0.01) and (62+/-3)% (P<0.01), respectively. 8-Br-cGMP (10(-7)~10(-3) mol/L) aslo attenuated 10(-8) mol/L Iso-induced [Ca(2+)](i) transient dose-dependent. The effect of VNP on [Ca(2+)](i) transient was almost abolished in the presence of HS-142-1 (2x10(-5) mol/L), an antagonist of the natriuretic peptide guanylate cyclase (GC) receptors. MB (10(-5) mol/L), an inhibitor of GC, not only blocked the effect of VNP in myocytes, but also augmented electrically-induced [Ca(2+)](i) transient. VNP and HS-142-1 themselves did not change the [Ca(2+)](i) transient in the cardiac myocytes significantly. But MB augmented the [Ca(2+)](i) transient in the cardiac myocytes significantly. These results suggest that VNP attenuates [Ca(2+)](i) transient induced by Iso. This effect is possibly achieved by binding VNP with the natriuretic peptide GC receptors in the myocytes, leading to an increase in intracellular cGMP.

Animals↗
PubMed2004

K317, R319, and E320 within the proximal C-terminus of the bradykinin B2 receptor form a motif important for phospholipase C and phospholipase A2 but not connective tissue growth factor related signaling.

We showed previously that large domain exchanges between the bradykinin B2 (BKB2) and angiotensin II type 1a (AT1a) receptors can result in functional hybrids. However, when we proceeded to exchange the entire bradykinin B2 receptor (BKB2R) C-terminal tail with the AT1aR C-terminus, the hybrid, while continuing to bind BK and be endocytosed as wild type (WT) BKB2R, lost much of its ability to activate phosphatidylinositol (PI) turnover or the release of arachidonic acid (ARA). In this study, we constructed chimeric receptors within the proximal C-terminus between the BKB2R and AT1aR or bradykinin B1 receptor (BKB1R). The mutant and WT receptor cDNAs were stably transfected into Rat-1 cells. Also, point mutations were generated to evaluate the role of the individual residues within this region. These chimeric studies revealed that the proximal portion of the BKB2R C-tail is crucial for G protein-linked BKB2R functions. This region could not be swapped with the AT1aR to obtain a BK activated PI turnover or ARA release. Further studies demonstrated that the distal portion (325-330) of this region is exchangeable; however, the middle portion (317-324) is not. Small motif exchanges within this section identified the KSR and EVY motifs as crucial for G(alphaq), G(alphai) related signaling of the BKB2R. Point mutations then showed that the charged amino acids K317, R319, and E320 are the residues critical for linking to PI turnover and ARA release. However, these proximal chimeras showed normal receptor uptake. Interestingly, while apparently not activating G protein-linked signaling, the proximal tail AT1aR exchange mutant and the entire C-terminus exchange hybrid continued to cause a substantial bradykinin effected increase in connective tissue growth factor (CTGF) mRNA level, as WT BKB2R.

Amino Acid Motifs↗
PubMed2004

A comparison of rice chloroplast genomes.

Using high quality sequence reads extracted from our whole genome shotgun repository, we assembled two chloroplast genome sequences from two rice (Oryza sativa) varieties, one from 93-11 (a typical indica variety) and the other from PA64S (an indica-like variety with maternal origin of japonica), which are both parental varieties of the super-hybrid rice, LYP9. Based on the patterns of high sequence coverage, we partitioned chloroplast sequence variations into two classes, intravarietal and intersubspecific polymorphisms. Intravarietal polymorphisms refer to variations within 93-11 or PA64S. Intersubspecific polymorphisms were identified by comparing the major genotypes of the two subspecies represented by 93-11 and PA64S, respectively. Some of the minor genotypes occurring as intravarietal polymorphisms in one variety existed as major genotypes in the other subspecific variety, thus giving rise to intersubspecific polymorphisms. In our study, we found that the intersubspecific variations of 93-11 (indica) and PA64S (japonica) chloroplast genomes consisted of 72 single nucleotide polymorphisms and 27 insertions or deletions. The intersubspecific polymorphism rates between 93-11 and PA64S were 0.05% for single nucleotide polymorphisms and 0.02% for insertions or deletions, nearly 8 and 10 times lower than their respective nuclear genomes. Based on the total number of nucleotide substitutions between the two chloroplast genomes, we dated the divergence of indica and japonica chloroplast genomes as occurring approximately 86,000 to 200,000 years ago.

Base Sequence↗