Biomedical subjects

X Ren

Publications and source records attributed to X Ren.

At least 55 records · Page 3Linked to original sources

PubMed2001

A novel mis-sense mutation (G1381A) in the G6PD gene identified in a Chinese man.

OBJECTIVE: To detect new mutations among 29 glucose-6-phosphate dehydrogenase (G6PD) deficient individuals from Yunnan province. METHODS: The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals. Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing. RESULTS: Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified. Nine cases remained to be defined. The G1381A mutation is a novel mis-sense mutation, with a substitution of threonine for alanine (A461T). The resultant G6PD had reduced enzymatic activity. In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation. CONCLUSION: A novel mis-sense mutation G1381A was found. This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity. The loss of the Stu I restriction site offers a rapid method for the detection of this mutation.

Adult↗

PubMed2001

[Assessing health state utility using the short form 36].

OBJECTIVE: To explore the methods of utility assessment using the short form 36. METHODS: The authors selected 70 people stratified by age, sex, and occupation in a city in Sichuan province, and investigated the preference of the population on each domain or item by paired comparison with other domains or items. Based on the preference, the weights of the domains and items were calculated. RESULTS: The weights of all the 8 domains and the items within 7 domains except the first domain "physical functions" were identified. The total score and the scores of the domains calculated by weighted adding method were significantly different from those calculated by simple adding method. However, only little variation of the scores of the domains between the two methods appeared. CONCLUSION: Utility calculated by weighted adding method may reflect people's preference to the health states more accurately. However, the value is limited in using weighted adding method for calculating the scores of domains.

Activities of Daily Living↗

PubMed2001

[Antioxidation of flavones of wheat germ on mammary tumor of rats].

The effect of flavonoids of wheat germ on mammary tumor of rats induced by 7,12-dimethylben(a) anthracene (DMBA) was investigated. Sprague-Dawley female rats (50 day-old, weighted around 176 g) were randomly divided into 4 groups. The negative and positive control group were fed on stoke diet. The high and low dose test groups were fed on diets with wheat germ flavonoids 10 and 2 g/kg respectively. Except rats in the negative control group, each rat was given DMBA 15 mg dissolved in 1.5 ml vegetable oil by tube feeding. After the administration of DMBA for 24 weeks, the incidence of tumor in the high dose test group was lower than that in the positive control group. The activity of blood and liver glutathione peroxidase (GSH-Px) and peroxidase dismutase(SOD) in the test groups was significantly higher than those in the positive control group, while the MDA level was significantly lower. The results suggested that the effect of flavonoids on inducing peroxidase might be one of the chemical prevention mechanisms on mammary tumors.

Animals↗

PubMed2001

[Factors that influence the quality of life of Sichuan population].

OBJECTIVE: To investigate the risk factors influencing quality of life with the aim of providing evidence for valid health promotion measures. METHODS: The authors used the short form 36 to assess the quality of life of 2249 residents in Sichuan Province. The data of potential risk factors including social economic status, culture, chronic condition and personal characteristics were collected. The Student t test, variance analysis, and stepwise multivariate regression methods were used to test the impacts of different risk factors on quality of life. RESULTS: Chronic condition, age, sex, educational level, marital status, occupation, personal income, number of family members, number of generation in a family, inhabitant places (urban or rural), and way of payment of medical expenditure were correlated with all or most of the domains of the short form 36 in t-test or one-way variance analysis. When the effect of interaction between factors were excluded by use of multivariate regression, the chronic condition, personal income, inhabitant places, age, and educational level remained to be significant risk factors. Marital status also had impacts on a few domains. CONCLUSION: The key steps of promoting the quality of life should include the prevention and control of chronic conditions, the development of economy, and the improvement of people's income and educational level. It is necessary to provide norms of the short form 36 stratified by inhabitant's place and age. Further research would be needed to provide evidence for the necessity of norms stratified by sex.

Adolescent↗

PubMed2001

[Assessing the quality of life of people with chronic diseases using SF-36].

OBJECTIVE: To analyze the influence of chronic diseases on the quality of life by using short form of 36 (SF-36). METHODS: Four hundred and thirty-eight people with chronic diseases were surveyed in a township and a city in Sichuan Province. The diseases were classified according to ICD-9 and the quality of life of people with chronic diseases of different systems was analyzed. RESULTS: The quality of life of people with chronic diseases of different systems was lower than that of general people aged 40 or above. The quality of life varied among people with chronic diseases of different systems in four fields, namely PF, SF, VT and MH. The main diseases that influenced the quality of life were mental disorders, infectious and parasitic diseases, the diseases of blood and blood-forming organs. CONCLUSION: The chronic diseases have decreased the quality of life. The diseases of different systems have had different influences on the quality of life. SF-36 is suitable for assessing the quality of life of people with chronic diseases. Quality of life should be taken as an important health index in chronic disease control and prevention.

China↗

PubMed2001

[Feasibility of using short form 36 in Chinese population].

OBJECTIVE: To explore the feasibility of using the SF-36 in Chinese population. METHODS: We tested the reliability and validity of the SF-36 in 1603 rural residents, 646 urban residents, 70 high school girls, 122 patients with osteoporosis, and 150 stroke patients. RESULTS: The reliability and validity of the SF-36 in general were acceptable, however, the reliability and validity varied among different domains and in different populations. The reliability and validity of the domains "limitations in physical activities", "limitations in usual role activities because of physical health problems", "bodily pain", and "general health perception" were better than those of the domains "vitality", "limitations in social activities", "limitations in usual role activities because of emotional problems", and "mental health". CONCLUSION: The results indicate that we can use the SF-36 in Chinese population, but we have to pay attentions to the variance of the reliability and validity in different populations, especially for the interpretation of the results of the domains related to mental and social functions.

Activities of Daily Living↗

PubMed2001

[The norms of SF-36 scale scores in urban and rural residents of Sichuan province].

OBJECTIVE: To develop the norms of SF-36 in Sichuan, China. METHODS: A total of 1603 rural residents and 646 urban residents were surveyed. Both the US scaling criteria and China scaling criteria were used to score the 8 domains of the SF-36 and compared with the norms of Hong Kong and US populations. RESULTS: The scores of the 8 domains of the SF-36 using China scaling criteria were highly correlated with those using the US scaling criteria, with correlation coefficients greater than 0.98, however, the mean scores using the two scaling criteria were different significantly. The norms of the Sichuan population were more similar to the Hong Kong norms than the US norms. The scores of the SF-36 were different between different age and sex groups and between urban and rural populations. CONCLUSION: We have developed the norms of SF-36 by age/sex groups in urban and rural population of Sichuan, China.

Activities of Daily Living↗

PubMed2001

[Synthesis, spectra and magnetic properties of ion-pair charge transfer complexes bis(1-(4-nitrobenzyl) pyridinium) bis(maleonitriledithiolato) cobaltate(II or III)].

Two new ion-pair charge transfer complexes, [NO2Py]x[Co(mnt)2](NO2Py = 1-(4-nitrobenzyl)pyridinium; mnt = male-onitriledithiolate; x = 1 or 2 for complex 2 or 1), were synthesized and characterized by element analysis(EA), electronic spray mass spactrum(ES-MS), infrared spectrum (IR) and reflection electrolic spectra. Variable temperature magnetic susceptibilities of the complexes in range of 77-300 K indicate that complex 2 exhibits diamagnetivity complex 2, and the magnetic behavior for complex 1 obeys modification Bleaney-Bowers equation, that is, chi m = [Ng2 mu B2/3k(T-theta)][1 + (1/3)exp(-2J/kT)]-1. The best fitting gives a good results: g = 2.392, 2J/k = 5.9 K, theta = -4.9 K and agreement factor R = 7.20 x 10(-9) (R = sigma (chi (i)obs-chi (i)calcd)2/sigma (chi (i)obs)2).

English Abstract↗

PubMed2000

The transport activity of the Na+-Ca2+ exchanger NCX1 expressed in HEK 293 cells is sensitive to covalent modification of intracellular cysteine residues by sulfhydryl reagents.

Membrane permeable N-ethylmaleimide (NEM) and (2-aminoethyl)methanethiosulfonatehydrobromide (MTSEA) inhibited the rat brain Na(+)-Ca(2+) exchanger RBE-2 (NCX1.5) expressed in HEK 293 cells in a dose dependent manner. 50% inhibition was obtained at 1 mm MTSEA and 1.65 mm NEM. External application of membrane impermeable [2-(trimethylammonium) ethyl]methanethiosulfonatebromide (MTSET) and sodium(2-sulfonatoethyl)methanethiosulfonate (MTSES) did not inhibit the transport activity in whole cells. Following reconstitution, however, of RBE-2 transfected cell proteins into proteoliposomes, external application of MTSET and MTSES led to a decrease in transport activity to 42.7 (S.D. = 9.1) and 51% (S.D. = 10.14), respectively. Similar results were obtained also when the rat heart isoform RHE-1 (NCX1.1) or the rat brain isoform RBE-1 (NCX1.4) was expressed. NEM and MTSEA inhibited Na(+) gradient-dependent Ca(2+) uptake also in HEK 293 cells expressing RBE-2/C14A/C20S/ C122S/C780S (numbering corresponds to RBE-2), a mutant in which all putative extracellular cysteines were exchanged. To study the accessibility of different cysteines to covalent modification, surface biotinylation of cells expressing the wild type exchanger and its mutants was carried out using 3-(N-maleimidylpropionyl)biocytin. Surface biotinylation revealed immunoreactive protein derived from the wild type Na(+)-Ca(2+) exchanger only if the transfected cells were exposed to the reducing agent Tris(2-carboxyethyl)phosphine. No reduction was needed when the single cysteine mutants of RBE-2, C14A, C20S, and C780S, were expressed. Treatment of the cells expressing these mutants with MTSET before biotinylation, led to a decrease in the amount of exchanger protein that was revealed. No immunoreactive protein was detected when the quadruple mutant RBE-2, C14A/C20S/C122S/C780S, was biotinylated, suggesting that no additional cysteines are accessible directly from the extracellular face of the membrane. Permeabilizing the cells expressing RBE-2/C14A/C20S/ C122S/C780S with streptolysin O resulted in biotinylation of the exchanger protein. Its amount decreased if exposure to NEM preceded streptolysin O treatment. Our results suggest that Na(+)-Ca(2+) exchange activity is inhibited by covalent modification with sulfhydryl reagents of cysteine residues that are accessible from the cytoplasmic face of the membrane.

Animals↗

PubMed2000

A bis-cyclodextrin diselenide with glutathione peroxidase-like activity.

A diselenide, 2,2'-diseleno-bis-beta-cyclodextrin (2-SeCD), was synthesized to imitate the antioxidant enzyme glutathione peroxidase (GPX). The GPX mimic accepts a variety of hydroperoxides as substrates. The GPX activities, reduction of H(2)O(2), tert-butyl hydroperoxide and cumenyl hydroperoxide by glutathione, are 7.4, 4.5 and 10.2 U/micromol, respectively. In contrast to ebselen (PZ51), the diselenide displays high GPX-like activity. The reduction of hydroperoxide by glutathione in the presence of a radical trap shows that the mimic catalyzes the reaction via a non-radical mechanism. A ping-pong mechanism was observed in the steady-state kinetic studies of the 2-SeCD-catalyzed reaction.

Animals↗

PubMed2000

Universal symmetry property of point defects in crystals

Point defects (vacancies, solute atoms, and disorder) are ubiquitous in crystalline solids. With in situ transmission electron microscopy we find clear evidence for the existence of a universal symmetry property of point defects; i.e., the symmetry of short-range order of point defects follows the crystal symmetry when in equilibrium. We further show that this symmetry-conforming property can lead to various interesting effects including "aging-induced microstructure memory" and the associated "time-dependent two-way shape memory."

Journal Article↗

PubMed2000

Processing of cdk5 activator p35 to its truncated form (p25) by calpain in acutely injured neuronal cells.

Recently, it was shown that conversion of cdk5 activator protein p35 to a C-terminal fragment p25 promotes a deregulation of cdk5 activity, which may contribute to neurodegeneration in Alzheimer's disease. In this study, we present evidence that calpain is a protease involved in the conversion of p35 to p25. To activate calpain, rat cerebellar granule neurons were treated with maitotoxin (MTX). A C-terminus-directed anti-p35 antibody detected that p35 conversion to p25 paralleled the formation of calpain-generated alpha-spectrin (alpha-fodrin) breakdown products (SBDP's) in a maitotoxin-dose-dependent manner. Two calpain inhibitors (MDl28170 and SJA6017) reduced p35 processing but were unchanged when exposed to the caspase inhibitor carbobenzoxy-Asp-CH(2)OC(=O)-2, 6-dichlorobenzene or the proteasome inhibitors (lactacystin and Z-Ile-Glu(OtBu)Ala-Leu-CHO). p35 protein was also degraded to p25 when rat brain lysate was subjected to in vitro digestion with purified mu- and m-calpains. Additionally, in a rat temporary middle cerebral artery occlusion model, p35 processing to p25 again paralleled SBDP formation in the ischemic core. Lastly, in malonate-injured rat brains, the ipsilateral side showed a striking correlation of SBDP formation with p35 to p25 conversion and tau phosphorylation (at Ser202 and Thr205) increase. These data suggest that calpain is a major neuronal protease capable of converting p35 to p25 and might play a pathological role of activating cdk5 and its phosphorylation of tau in Alzheimer's disease.

Animals↗

PubMed2000

Osteomyocutaneous flap as a preclinical composite tissue allograft: swine model.

Composite tissue allotransplantation (CTA) constitutes one of the last frontiers of microsurgery. Prior to its clinical application, the long-term efficacy of modern immunotherapy must be tested in a pre-clinical CTA model. Based on the concept of osteomyocutaneous forearm flap, we developed a CTA flap model in swine. After identifying the vascular territory of the flaps in six pigs (vascular casting), flaps were transplanted from mismatched donor to recipient pigs (n = 6). Rejection was assessed daily by visual inspection and histopathology of biopsy specimens. Recipient pigs were able to ambulate immediately following surgery. There were no flap failures owing to technical or surgical complications. Rejection occurred over a period of 7 days as manifested by edema, cellular infiltration, epidermalysis, and thrombosis. This pre-clinical flap model is excellent for evaluating the effectiveness of modern immunotherapy because it is anatomically and immunologically relevant and because the minimal morbidity caused to the animal permits long-term studies.

Animals↗

PubMed2000

Hand transplantation: comparisons and observations of the first four clinical cases.

Twenty, 15, and 8 months after the first four successful human hand transplant procedures were performed in Lyon (France), Louisville (U. S.), and Guangzhou (China), the transplant teams convened in Louisville, Kentucky, to share their experiences at the Second International Symposium on Composite Tissue Allotransplantation. This article presents reconstructive and immunological data from these landmark procedures in tabular format, in an attempt to answer some key questions about early outcomes of clinical hand transplantation. On the basis of these data, the initial outcomes of the first four hand transplants are encouraging and warrant proceeding with additional hand transplantations.

Adult↗

PubMed2000

Swine composite tissue allotransplant model for preclinical hand transplant studies.

Our laboratory previously developed and used an orthotopic radial forelimb osteomyocutaneous flap in the pig as a preclinical composite tissue allograft (CTA) model. To ensure that it mimicked the clinical situation as closely as possible we developed this model taking many immunologic and reconstructive considerations into account. While our original pig CTA model was ideal for studying the methods of preventing skin, muscle, bone, vessel and nerve rejection, and systemic toxicity, it did not include specialized tissues/structures of a joint and digit. Therefore, we were unable to evaluate rejection of these specialized tissues and their functional properties. Recognizing the importance of assessing joint rejection and function in hand transplantation research we developed a new swine forelimb CTA model that included the animal's medial digit. The present study describes the anatomy and the transplantation technique used in this new preclinical CTA model. We transplanted a radial osteomyocutaneous flap that included the medial digit between two size- (17-21 kg) and age- (6-8-week) matched farm pigs. We removed the digit from the recipient pig's forelimb in continuity with a section of the radial bone and replaced it with the same structure transplanted from a donor pig. After transplantation, a full-length cast was placed on the recipient pig's operated limb and changes in flap color, temperature and the presence of edema were monitored continuously for 6 h, and then regularly at predetermined intervals over 4 days. No weight bearing restrictions were placed on the animal's operated limb. After 4 days, the animal was euthanized. Direct visual monitoring of the allograft during 4 days revealed it was viable with no signs of graft failure due to technical complications associated with the transplant procedure. Upon waking from anesthesia, the animal stood and wandered freely about its cage with no apparent difficulty. Based on the animal's high level of activity at this time, we concluded that the procedure caused it minimal morbidity. At 4 days after the operation, early signs of rejection (skin erythema and edema) were observed. By incorporating a digit into our original CTA pig forelimb model we have made it a better model for performing preclinical hand transplant studies. The added advantage of being able to assess methods of preventing rejection in the specialized joint/digital tissues (articular cartilage, digital flexor and extensor systems, the nail complex) and assess long-term function of these structures is important. The fact that the procedure does not cause major morbidity to the animal makes it possible to conduct long-term graft survival and functional studies.

Animals↗

PubMed2000

Discovery of a novel, paternally expressed ubiquitin-specific processing protease gene through comparative analysis of an imprinted region of mouse chromosome 7 and human chromosome 19q13.4.

Using mouse BAC clones spanning an imprinted interval of proximal mouse chromosome 7 and the genomic sequence of the related interval of human chromosome 19q13.4, we have identified a novel mouse gene, Usp29 (ubiquitin-specific processing protease 29), near two known imprinted genes, Peg3 and Zim1. Gene Usp29 is located directly adjacent to Peg3 in a "head-to-head" orientation, and comprises exons distributed over a genomic distance of at least 400 kb. A similar human gene is also found in the homologous location in human chromosome 19q13.4. The mouse Usp29 gene is also imprinted and is transcribed mainly from the paternal allele with highest expression levels in adult brain, especially in the cerebral cortex and hippocampus, and in the forebrain, face, and limb buds of midgestation mouse embryos. Analysis of a full-length 7.6-kb cDNA clone revealed that Usp29 encodes an 869-amino-acid protein that displays significant homology with yeast and nematode ubiquitin carboxyl-terminal hydrolases. These data suggest that, like the candidate Angelman syndrome gene Ube3a (ubiquitin ligase), Usp29 may represent another imprinted gene involved in the ubiquitination pathway. This identification of a third imprinted gene, Usp29, from the Peg3/Zim1-region confirms the presence of a conserved imprinted domain spanning at least 500 kb in the proximal portion of mouse chromosome 7 (Mmu7).

Amino Acid Sequence↗

PubMed2000

Distinctions between bovine herpesvirus 1 and herpes simplex virus type 1 VP22 tegument protein subcellular associations.

The alphaherpesvirus tegument protein VP22 has been characterized with multiple traits including microtubule reorganization, nuclear localization, and nonclassical intercellular trafficking. However, all these data were derived from studies using herpes simplex virus type 1 (HSV-1) and may not apply to VP22 homologs of other alphaherpesviruses. We compared subcellular attributes of HSV-1 VP22 (HVP22) with bovine herpesvirus 1 (BHV-1) VP22 (BVP22) using green fluorescent protein (GFP)-fused VP22 expression vectors. Fluorescence microscopy of cell lines transfected with these constructs revealed differences as well as similarities between the two VP22 homologs. Compared to that of HVP22, the BVP22 microtubule interaction was much less pronounced. The VP22 nuclear interaction varied, with a marbled or halo appearance for BVP22 and a speckled or nucleolus-bound appearance for HVP22. Both VP22 homologs associated with chromatin at various stages of mitosis and could traffic from expressing cells to the nuclei of nonexpressing cells. However, distinct qualitative differences in microtubule, nuclear, and chromatin association as well as trafficking were observed. The differences in VP22 homolog characteristics revealed in this study will help define VP22 function within HSV-1 and BHV-1 infection.

Amino Acid Sequence↗

PubMed2000

Changes in respiratory control in humans induced by 8 h of hyperoxia.

In humans, 8 h of isocapnic hypoxia causes a progressive rise in ventilation associated with increases in the acute ventilatory responses to hypoxia (AHVR) and hypercapnia (AHCVR). To determine whether 8 h of hyperoxia causes the converse of these effects, three 8-h protocols were compared in 14 subjects: 1) poikilocapnic hyperoxia, with end-tidal PO(2) (PET(O(2))) = 300 Torr and end-tidal PCO(2) (PET(CO(2))) uncontrolled; 2) isocapnic hyperoxia, with PET(O(2)) = 300 Torr and PET(CO(2)) maintained at the subject's normal air-breathing level; and 3) control. Ventilation was measured hourly. AHVR and AHCVR were determined before and 0.5 h after each exposure. During isocapnic hyperoxia, after an initial increase, ventilation progressively declined (P < 0.01, ANOVA). After exposure to hyperoxia, 1) AHVR declined (P < 0.05); 2) ventilation at fixed PET(CO(2)) decreased (P < 0.05); and 3) air-breathing PET(CO(2)) increased (P < 0.05); but 4) no significant changes in AHCVR or intercept were demonstrated. In conclusion, 8 h of hyperoxia have some effects opposite to those found with 8 h of hypoxia, indicating that there may be some "acclimatization to hypoxia" at normal sea-level values of PO(2).

Adolescent↗