Biomedical subjects

Qing Chang

Publications and source records attributed to Qing Chang.

At least 73 records · Page 4Linked to original sources

PubMed2004

[Effect of selection techniques on chromosome and ultrastructure of human spermatozoa].

OBJECTIVE: To know the effect of different selection techniques on chromosome abnormality rate and the percentage of spermatozoa with relatively intact head ultrastructure in human sperm. METHODS: The selection techniques of swim-up, Percoll density gradient centrifugation and doule-flection tube were used to observe sperm chromosome abnormality rate, sex chromosomal ratio and the percentage of spermatozoa with relatively intact head ultrastructure. RESULTS: The sperm chromosome abnormality rate, sex chromosomal ratio and the percentage of spermatozoa with relatively intact head ultrastructure remained unchanged after the application of the three selection techniques(P > 0.05). CONCLUSION: The three selection techniques used in this study neither increase the damage to sperm ultrastructure nor exert effects on human chromosome.

Adult↗

PubMed2004

[Isolation of partial outer supporting cells from guinea pig cochlea].

OBJECTIVE: To investigate the method of isolating partial outer supporting cells (Deiters' cells, Hensen cells and Outer pillar cells) from guinea-pig cochlea and to try to establish the morphological criteria for these outer supporting cells viability. METHOD: The basal membrane was dissected from the pigmental guinea pig cochlea, and th incubated with enzyme (0.5 mg/ml), then mechanically trituated by micropipetee. RESULT: A large number of living Deiters' cells and Hensen cells could be obtained from the guinea pig cochlear which kept a good condition in the next eight hours. However, the isolated outer pillar cells, with a more vulnerable viability, had a low yield and degenerated in the followed five hours. CONCLUSION: The key to success in isolating outer supporting cells, mainly Deiters' cells and Hensen's cells, from the guinea pig cochlea is to familiarize with the anatomical characteristics of the cochlea and to get the intact organ of Corti, as well as to increase the concentration of enzyme. Moreever, the later four criteria for outer hair cells viability are also fit well for these isolated Deiters' cells, Hensen's cells and Outer pillar cells.

Animals↗

PubMed2004

[Treatment of chronic Achilles tendon rupture by use of allogeneic tendon].

OBJECTIVE: To evaluate the clinical result of allogeneic tendon in treatment of chronic Achilles tendon rupture. METHODS: From July 1996 to November 2000, 6 cases of chronic Achilles tendon rupture were treated by use of allogeneic flexor tendon to repair Achilles tendon with Bosworth way. Five cases were followed up 27-53 months with an average of 38.5 months. RESULTS: According to Arner-Lindholm criteria for curative result, the result was excellent in 1 case and good in 4 cases. CONCLUSION: Allogeneic tendon in repair of chronic Achilles tendon is effective. It can avoid the injury and complication caused by autograft.

Achilles Tendon↗

PubMed2004

[A case-control study on the risk factors of Alzheimer's disease in military elderly men].

OBJECTIVE: To investigate the risk of Alzheimer's disease (AD) associated with life style, early exposure to magnetic fields, family history of dementia and other risk factors. METHODS: We conducted a case-control study among the inpatients of Chinese PLA General Hospital in 2000 - 2003. Sixty-two AD cases and 124 controls were selected and matched for age. Univariate and multivariate analyses were conducted using logistic regression model. RESULTS: All subjects were males aged 66 to 102. In univariate analysis, lack of social activities, more physical exercises, early exposure to magnetic fields, suffering from negative life events and family history of dementia were statistically different between two groups (P < 0.05). Multivariate analysis showed that after adjusting for potential confounders, suffering from negative life events, family histories of dementia increased the risk of AD with odds ratio (OR) and 95% confidence interval (CI) 3.27 (1.53 - 6.97) and 5.78 (1.39 - 24.10). Early exposure to magnetic fields seemed a possible risk factor for AD, with OR (95% CI) 2.49 (0.96 - 6.45). The amount of social activities, cigarette smoking and history of cancers were negatively correlated with AD and their ORs (95% CI) were 0.81 (0.72 - 0.92), 0.46 (0.21 - 1.00) and 0.31 (0.12 - 0.82) respectively. CONCLUSION: The study demonstrated that suffering from negative life events and family history of dementia were risk factors for AD, and the early exposure to magnetic fields might also play a role.

Aged↗

PubMed2004

[Population genetic structure of Pelophylax nigromaculata in Chinese mainland based on mtDNA control region sequences].

Molecular genetic data were used to investigate population genetic structure and differentiation of Pelophylax nigromaculata (Anura: Ranidae). Frogs were collected from 12 localities across Chinese mainland. Sample sizes of up to 10 frogs per population were assayed for mitochondrial control region sequence variation. The aligned 685 bp of the 5'CR include 111 variable sites. Sixty-seven haplotypes were defined. Most of the haplotypes are unique to local populations, only 7 of the 67 are shared among a few local populations. The overall species haplotype diversity is quite high (h = 0.98 +/- 0.005), and the nucleotide diversity is also high (pi = 0.0303 +/- 0.0029). This is corresponding to huge population size and extensive distribution of Pelophylax nigromaculata throughout Palaearctic and Oriental Regions. Phylogenetic tree of mtDNA control region haplotypes based on maximum parsimony algorithm and reconstructed phylogenetic relationships among the local populations based on neighbor joining algorithm all suggest that the haplotypes of Jiling and Liaoning populations in northeastern China have a sister relationship with 10 local populations in northern, central, southern and southwestern China. The analysis of molecular variance (AMOVA), the pairwise FST values and nucleotide divergence all support significant population subdivision between the Jilin-Liaoning group and multi-population group. The most possible cause of the significant genetic subdivision between the two groups might be referred to the effect of Quaternary glaciation. The possible reasons for the lack of obvious geographic structure on the whole in the multi-population group and the genetic differentiation in some local populations of the multi-population group were also discussed.

Animals↗

PubMed2004

[Laparoscopic suture uterosacral ligament hysteropexy for uterine prolapse].

OBJECTIVE: To investigate possibility and effect of laparoscopic suture uterosacral ligament hysteropexy or colpopexy for women with uterine prolapse. METHODS: Thirty-two women with symptomatic uterine prolapse underwent laparoscopic suture uterosacral ligament hysteropexy. At the laparoscopic suture hysteropexy or colpopexy, the pouch of Douglas was closed and the uterosacral ligaments were plicated and reattached to the cervix. All patients were multipara and menopausal with prolapse of anterior wall of vagina. Additionally, 4 patients were with prolapse of posterior wall of vagina, 15 with stress urinary incontinence, and 4 with myomas. RESULTS: All procedures were successfully completed laparoscopically. The mean operating time for the laparoscopic suture hysteropexy or colpopexy alone was (32 +/- 11) min (range 20 approximately 80 min), and the mean blood loss was less than 50 ml. After a mean follow-up of (12 +/- 6) months (range 4 approximately 28 months), 23 women had no symptoms of uterine prolapse and seven had no objective evidence of uterine prolapse. Two women presented recurrence of uterine prolapse 3 months after operation. CONCLUSIONS: The laparoscopy suture hysteropexy or colpopexy is effective and safe in the management of symptomatic uterine prolapse. It may be an appropriate procedure for women with uterine prolapse hoping for uterine preservation.

Aged↗

PubMed2003

The role of PKCdelta and PKCepsilon in the neonatal rat colon in response to hypoxia challenge.

Previous studies have determined that, in response to bacterial endotoxin, the colonic mucosa of the 10-d-old neonatal rat was more susceptible to injury than was the colon of the 25-d-old mature animal. Furthermore, it is known that certain isoforms of protein kinase C (PKC), specifically PKCdelta and PKCepsilon, mediate intestinal inflammatory responses to specific challenges. Therefore, in the present study, we have examined the association between the activation of these PKC isoforms and the enhanced susceptibility to hypoxia-induced challenge. In response to exposure to a hypoxic environment (14% O2/86% N2, 30 min), the degree of inflammation and tissue damage was significantly greater in 10- than in 25-d-old rats. The injury in 10-d-old rats was associated with activation of PKCdelta and PKCepsilon as estimated by translocation of the isoform from cytosolic to membrane fraction of the tissue lysate. There was no activation of either isoform in colons from 25-d-old rats after hypoxia. Pretreatment of 10-d-old rats with epidermal growth factor (EGF) (10 microg/kg) but not 16,16 dimethyl prostaglandin E2 (2 microg/kg) significantly reduced the extent of colonic injury, whereas neither agent was able to exert significant protection of the colonic mucosa of 25-d-old rats. PKC activation associated with hypoxia was not evident after EGF treatment in 10-d-old rats. In 25-d-old rats, prostaglandin E2 treatment was linked with an activation of PKCepsilon only. In conclusion, these data suggest that activation of PKCdelta and PKCepsilon is associated with the enhanced susceptibility to injury evident in suckling neonatal rat colon. EGF-mediated protection of the colon in these animals results in a removal of this PKC activation.

Animals↗

PubMed2003

Intra-hippocampal lidocaine injections impair acquisition of a place task and facilitate acquisition of a response task in rats.

While hippocampal lesions impair learning and memory in many tasks, such lesions also enhance learning and memory in other tasks. The present experiment examines the effects of inactivation of the hippocampus with lidocaine prior to learning, to find food in a place or response version of a four-arm plus-shaped maze. Rats received lidocaine injections 6 min prior to training. Rats were trained in a single session to a criterion of 9/10 correct responses. Compared to artificial cerebrospinal fluid (aCSF)-injected controls, rats with intra-hippocampal injections of lidocaine exhibited significantly retarded acquisition of place learning. In marked contrast, rats with intra-hippocampal injections of lidocaine exhibited significantly enhanced acquisition of response learning compared to their controls. In addition to showing that the hippocampus is important for learning the place task, these findings suggest that processing of information by the hippocampus interferes with learning a task dependent on a different neural system.

Anesthetics, Local↗

PubMed2003

Switching memory systems during learning: changes in patterns of brain acetylcholine release in the hippocampus and striatum in rats.

This experiment measured acetylcholine (ACh) release simultaneously in the hippocampus and striatum while rats were trained in a cross maze. Consistent with past findings, rats initially showed learning on the basis of place (i.e., turning to the correct position relative to the room), but after extensive training, rats shifted to learning on the basis of response (i.e., turning to the right/left to find the food). Profiles of ACh release in the hippocampus and striatum were markedly different during training. In the hippocampus, ACh release increased by approximately 60% at the onset of training and remained at that level of release throughout training, even after the rats began to show learning on the basis of turning rather than place. In the striatum, increases in ACh release occurred later, reaching asymptotic increases of 30-40%, coincident with a transition from expressing place learning to expressing response learning. These findings suggest that the hippocampal and striatal systems both participate in learning in this task, but in a manner characterized by differential activation of the neural systems. The hippocampal system is apparently engaged first before the striatum is activated and, to the extent the hippocampus is important for place learning, promotes the use of a place solution to the maze. Later in training, although the hippocampus remains activated, the striatum is also activated in a manner that may enable the use of a response strategy to solve the maze. These findings may offer a neurobiological marker of a transition during skill learning from declarative to procedural learning.

Acetylcholine↗

PubMed2003

Aldo-keto reductases as modulators of stress response.

Human aldose reductase (AKR1B1) has been implicated as a factor in the pathogenesis of diabetic complications. However, little is known about the physiological role of this enzyme or of related aldo-keto reductases in human tissues. In mammalian systems, a gene knock out approach is often employed as an experimental strategy to probe for gene function. However, in the murine system, phenotypic characterization of an aldose reductase (AKR1B3) knock out is likely to be complicated due to functional compensation by redundant AKRs including AKRs 1A (aldehyde reductase), 1B7 (FR-1) and 1B8 (MVDP). As an alternate strategy, we are examining the budding yeast Saccharomyces cerevisiae as a model system for a functional genomics study of AKRs. A distinct advantage of this system centers on the ability to readily ablate multiple targeted genes in a single strain. In addition to providing insights into functional redundancy, this system allows us to use a genetic approach to study possible effector pathways associated with one or more individual genes. Yeast open reading frames (ORFs) encoding AKRs with functional similarity to human aldose reductase (AKR1B1) were identified by BLAST analysis and were functionally validated by studies of recombinant proteins. By ablating three of the yeast AKR genes most functionally similar to AKR1B1, we have created a unique strain of S. cerevisiae that shows enhanced sensitivity to stress. Ongoing studies with oligonucleotide arrays show that the triple null strain has an altered transcription profile consistent with an enhanced stress response in comparison with the parental strain. These data indicate that AKR-null strains may provide new insights into signaling mechanisms involving this family of proteins.

Alcohol Oxidoreductases↗

PubMed2003

Echocardiographic diagnosis and follow-up of left ventricular pseudoaneurysm complicating bacterial pericarditis.

Two-dimensional echocardiography demonstrated a pseudoaneurysm of the lateral wall of the left ventricle in a 13-year-old girl with bacterial pericarditis. The echocardiographic findings included a 5-mm discontinuity in the lateral wall of the left ventricle, an associated anechoic collection (5.6 x 5.1 cm), and a narrow communication between the left ventricle and the anechoic collection. Color Doppler imaging demonstrated flow through the communication between the left ventricle and the aneurysmal cavity. The patient and her family refused surgery. A follow-up echocardiographic examination more than 6 years later demonstrated disappearance of the discontinuity of the left ventricular lateral wall, no flow between the left ventricle and the pseudoaneurysm, and thrombus formation within the pseudoaneurysm.

Adolescent↗

PubMed2003

GB virus type C/hepatitis G virus: a non-pathogenic flavivirus associated with prolonged survival in HIV-infected individuals.

GB virus C (GBV-C) is a common virus that does not appear to cause disease. GBV-C persists in up to 50% of exposed individuals, and virus replication appears to be in lymphocytes including CD4+ T cells. GBV-C infection is common among HIV-positive people, and several studies have found that HIV-positive individuals co-infected with GBV-C survive for statistically significantly longer periods of time than people without GBV-C. In vitro studies suggest that GBV-C inhibits HIV replication and alters cytokine, chemokine and chemokine receptor expression. Thus, GBV-C may be a major factor influencing the natural history of HIV disease.

Animals↗

PubMed2003

Expression of a Brassic napus glutamate 1-semialdehyde aminotransferase in Escherichia coli and characterization of the recombinant protein.

Glutamate 1-semialdehyde aminotransferase (GSA-AT) is a key regulatory enzyme, which converts glutamate 1-semialdehyde (GSA) to 5-aminolevulinic acid (ALA) in chlorophyll biosynthesis. ALA is the universal precursor for the synthesis of chlorophyll, heme, and other tetrapyrroles. To study the regulation of chlorophyll biosynthesis in Brassica napus, two cDNA clones of GSA-AT were isolated for genetic manipulation. A SalI-XbaI fragment from one of the two cDNA clones of GSA-AT was used for recombinant protein expression by inserting it at the 3' end of a calmodulin-binding-peptide (CBP) tag of the pCaln vector. The CBP tagged recombinant protein, expressed in Escherichia coli, was purified to apparent homogeneity in a one step purification process using a calmodulin affinity column. The purified CBP tagged GSA-AT is biologically active and has a specific activity of 16.6 nmol/min/mg. Cleavage of the CBP tag from the recombinant protein with thrombin resulted in 9.2% loss of specific activity. However, removal of the cleaved CBP tag from the recombinant protein solution resulted in 60% loss of specific activity, suggesting possible interactions between the recombinant protein and the CBP tag. The enzyme activity of the CBP tagless recombinant protein, referred as TR-GSA-AT hereafter, was not affected by the addition of pyridoxamine 5' phosphate (PMP). Addition of glutamate and pyridoxal 5' phosphate (PLP) to the TR-GSA-AT enhanced the enzyme activity by 3-fold and 3.6-fold, respectively. Addition of both glutamate and PLP increased the enzyme activity by 4.6-fold. Similar to the GSA-AT of B. napus, the active TR-GSA-AT is a dimeric protein of 88 kDa with 45.5 kDa subunits. As the SalI-XbaI fragment encodes a biologically active GSA-AT that has the same molecular mass as the native GSA-AT, it is concluded that the SalI-XbaI fragment is the coding sequence of GSA-AT. The highly active polyclonal antibodies generated from TR-GSA-AT were used for the detection of GSA-AT of B. napus.

Amino Acid Sequence↗

PubMed2003

Engraftment of quiescent progenitors and conversion to full chimerism after nonmyelosuppressive conditioning and hematopoietic cell transplantation in miniature swine.

Our laboratory has previously reported a nonmyelosuppressive preparative regimen for hematopoietic cell transplantation that leads to mixed chimerism and allograft tolerance in miniature swine across minor and major histocompatibility disparities. Stable chimerism persisted in most of these animals but was restricted to T cells and confined to peripheral blood. Because of the importance of myeloid and erythroid progenitors for the treatment of hematologic disorders, the objective of this study was to assess whether such cells existed in the bone marrow of these lymphoid chimeras as an indication of functional engraftment. Colony-formation assays were performed on donor inocula before infusion and on bone marrow cells harvested from the transplant recipients. Donor-origin myeloid/erythroid progenitor colonies were detected in bone marrow from 6 of 7 lymphoid chimeric recipients. A delayed donor leukocyte infusion successfully converted a stable lymphoid chimera to full multilineage chimerism within 2 weeks. Donor-origin myeloid/erythroid progenitors could be detected in the bone marrow of a host-matched recipient after myeloablation and adoptive transfer of mobilized cells from one of the engrafted lymphoid chimeras. These data suggest that even when only lymphoid chimerism is readily detected by flow cytometry, dormant myeloid/erythroid progenitors can exist and subsequent conversion to full donor chimerism can be achieved. The ability to establish multilineage engraftment and chimerism without significant toxicity may have important clinical implications for the management of nonmalignant hematopoietic disorders and hematologic malignancies.

Animals↗

PubMed2003

Chlorophyll reduction in the seed of Brassica napus with a glutamate 1-semialdehyde aminotransferase antisense gene.

Chlorophyll reduction in the seed of Brassica can be achieved by downregulating its synthesis. To reduce chlorophyll synthesis, we have used a cDNA clone of Brassica napus encoding glutamate 1-semialdehyde aminotransferase (GSA-AT) to make an antisense construct for gene manipulation. Antisense glutamate 1-semialdehyde aminotransferase gene (Gsa) expression, directed by a Brassica napin promoter, was targeted specifically to the embryo of the developing seed. Transformants expressing antisense Gsa showed varying degrees of inhibition resulting in a range of chlorophyll reduction in the seeds. Seed growth and development were not affected by reduction of chlorophyll. Seeds from selfed transgenic plants germinated with high efficiency and growth of seedlings was vigorous. Seedlings from T2 transgenic lines segregated into three distinctive phenotypes: dark green, light green and yellow, indicating the dominant inheritance of Gsa antisense gene. These transgenic lines have provided useful materials for the development of a low chlorophyll seed variety of B. napus.

Amino Acid Sequence↗

PubMed2003

Impaired endothelial function in the brachial artery after Kawasaki disease and the effects of intravenous administration of vitamin C.

BACKGROUND: Previous studies in patients with a history of Kawasaki disease have focused on vascular endothelial function in coronary arteries, and the endothelial function of systemic arteries is not fully understood. Furthermore the effect of vitamin C on systemic endothelial function after Kawasaki disease has not been elucidated. OBJECTIVES: We attempted to analyze endothelium-dependent vasodilatation in the brachial artery after Kawasaki disease by using high resolution ultrasonography and to investigate whether the acute administration of vitamin C could restore such systemic endothelial dysfunction. METHODS: We compared 39 patients (7.1 +/- 2.7 years) 1.0 to 9.6 years after acute Kawasaki disease with 17 matched healthy subjects (7.0 +/- 3.1 years) as controls. Using high resolution vascular ultrasound, we measured brachial artery responses to reactive hyperemia (with increased flow causing endothelium-dependent dilatation) and sublingual nitroglycerin (causing endothelium-independent dilatation). RESULTS: The percent change in diameter of the brachial artery induced by reactive hyperemia in the patients with a history of Kawasaki disease (6.2 +/- 3.9%) was significantly lower than that in the control group (14.1 +/- 6.8%; P < 0.0001). No significant difference could be found in percent change in diameter induced by sublingual administration of nitroglycerin between the control (33.2 +/- 13.7%) and the patients with a history of Kawasaki disease (30.6 +/- 9.2%; P = 0.49). There was no significant difference in percent change in diameter of the brachial artery induced by reactive hyperemia between the patients who received gamma-globulin (6.0 +/- 4.0%) and those who did not receive gamma-globulin (7.9 +/- 3.3%; P = 0.33). Intravenous infusion of vitamin C significantly increased the percent change in diameter of brachial artery induced by reactive hyperemia in 19 patients with history of Kawasaki disease (6.6 +/- 3.5 to 13.0 +/- 5.5%; P < 0.0001), whereas no significant increase was seen in the percent change in diameter of brachial artery induced by reactive hyperemia in 20 patients with history of Kawasaki disease after placebo administration (6.5 +/- 4.5 to 7.3 +/- 4.9%; P = 0.20). CONCLUSIONS: Our study showed decreased percent change in diameter of the brachial artery induced by reactive hyperemia in patients with history of Kawasaki disease compared with the healthy children, indicating that systemic endothelial dysfunction exits after Kawasaki disease. Although such systemic endothelial dysfunction after Kawasaki disease is not influenced by early treatment with high dose gamma-globulin in the acute stage of Kawasaki disease, it can be restored by the acute intravenous administration of vitamin C.

Adolescent↗

PubMed2003

Tissue involution and the acute phase response.

After their roles in reproduction are completed, the mass of the uterus and the mammary gland decrease rapidly by the process of involution that involves an ordered series of events including apoptosis, neutrophil entry, the release of degradative enzymes, and phagocytosis of cellular debris. The acute phase proteins are produced by the liver and other tissues in response to inflammation or a toxic challenge. Uterocalin (SIP24/24p3) is one of these proteins. During involution, the mammary gland and uterus express high levels of uterocalin that reach an average of 0.2-0.5% of the total extractable protein at its peak. Uterocalin and its orthologues have been demonstrated in vitro to (1). bind certain fatty acids and (2). specifically induce apoptosis in neutrophils and other leukocytes. The period of uterocalin expression during involution is consistent with the hypothesis that one of its physiological roles is to induce apoptosis of invading neutrophils and delay the entry of neutrophils into the tissue until the second phase of involution. Interestingly, it has been shown that uterocalin expression remains higher in primiparous gland than in virgin glands after the pregnant glands have completely involuted. This observation and the known protective effect of early pregnancy on later development of breast cancer suggest that the ability of uterocalin to induce apoptosis in neutrophils might also decrease oxidative and carcinogenic activity in the gland and result in a lower mutation rate and thus a lower probability of cancer in the primiparous gland.

Acute-Phase Proteins↗

PubMed2003

Chronic traumatic pseudoaneurysm of the ascending aorta causing right ventricular inflow obstruction.

A 28-year-old man developed exertional dyspnea and peripheral edema 1 year after the initial blunt trauma to the chest. The diagnosis of pseudoaneurysm (PSA) of the ascending aorta was made based on the echocardiographic finding of a large echo-free space that communicated with the ascending aorta through the defect in the ascending aortic wall. The PSA caused a right ventricular inflow obstruction with increased diastolic transtricuspid blood flow velocity up to 2.7 m/s. Following the excision of the PSA and repair of the communication between it and the ascending aorta, the sizes of the right atrium and right ventricle, and the diastolic transtricuspid blood flow velocity, normalized.

Adult↗