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Biomedical subjects

X Wei

Publications and source records attributed to X Wei.

At least 109 records · Page 6Linked to original sources
PubMed1998

Maturation-related compressive properties of rabbit knee articular cartilage and volume fraction of subchondral tissue.

OBJECTIVE: Knowledge about the physiologic change in cartilage biomechanics, accompanying the structural remodeling of the cartilage bone unit during maturation, may have relevance to understand the development of joint disease. The purpose of this study was to investigate maturation-dependent changes of compressive properties of articular cartilage and volume fraction of subchondral tissue in healthy rabbit knees. METHODS: Cartilage compressive properties (instantaneous and creep moduli) were tested at seven defined knee joint regions of five young (ten weeks), five adolescent (eighteen weeks) and five adult (above thirty-one weeks) healthy rabbits with in-situ indentation tests. Morphometric analysis of volume fraction of subchondral tissue was carried out at four regions. RESULTS: Cartilage stiffness (instantaneous modulus) decreased between infancy and adolescence (P < 0.009), and stayed then the same. A simultaneous significant change in (50-second) creep modulus was only observed at one region, but both moduli correlated to each other. Subchondral tissue consisted of cancellous bone in the young, and formed a more solid bone plate not before adolescence. Its volume fraction increased from infancy to adolescence (P < 0.001), but stayed then the same. There was a significant inverse correlation between the volume fraction of subchondral tissue and cartilage stiffness at the four measured regions (R2 = -0.59). The arrangement of collagen fiber bundles in the deeper cartilage layers changed from a mesh-like structure in the young to a more perpendicular alignment in the adolescent and adult. CONCLUSION: The maturation-related change in compressive properties coincided with a conspicuous change in volume fraction of the subchondral tissue. The main change appeared around puberty.

Animals↗
PubMed1998

Primary end points in phase III clinical trials of severe head trauma: DRS versus GOS. The American Brain Injury Consortium Study Group.

The most commonly used primary end point in phase III clinical trials of severe head trauma is the Glasgow Outcome Scale (GOS), usually dichotomized to favorable (good) and unfavorable (poor) outcomes. The alternative endpoints include the Disability Rating Scale (DRS) with a 31-point scale. The purpose of this study was to compare DRS and GOS using the data collected from two completed clinical trials organized by the American Brain Injury Consortium and two pharmaceutical companies. The two outcome scales were examined and compared in terms of the correlation between the two scales, sensitivity, and p values between the differences between two arms of the trials. There was no indication that the DRS was more sensitive or advantageous relative to the dichotomized or four-category GOS. In addition, the highly significant correlation between the two outcome scales (r = 0.95; p < 0.0001) could not justify the DRS as an end point. The other problems with the DRS include the difficulty of determining the clinically meaningful difference in designing trials. The study suggested that the GOS is a better primary end point than DRS.

Adult↗
PubMed1998

Nomenclature for human DPYD alleles.

To standardize DPYD allele nomenclature and to conform with international human gene nomenclature guidelines, an alternative to the current arbitrary system is described. Based on recommendations for human genome nomenclature, we propose that each distinct allele be designed by DPYD followed by an asterisk and an Arabic numeral. The number specifies the key mutation and, where appropriate, a letter following the number indicates an additional mutation on the mutant allele. Criteria for classification as a distinct allele are also presented.

Alleles↗
PubMed1998

Structure of double-shelled rice dwarf virus.

Rice dwarf virus (RDV), a member of the Reoviridae family, is a double-stranded RNA virus. Infection of rice plants with RDV reduces crop production significantly and can pose a major economic threat to Southeast Asia. A 25-A three-dimensional structure of the 700-A-diameter RDV capsid has been determined by 400-kV electron cryomicroscopy and computer reconstruction. The structure revealed two distinctive icosahedral shells: a T=13l outer icosahedral shell composed of 260 trimeric clusters of P8 (46 kDa) and an inner T=1 icosahedral shell of 60 dimers of P3 (114 kDa). Sequence and structural comparisons were made between the RDV outer shell trimer and the two crystal conformations (REF and HEX) of the VP7 trimer of bluetongue virus, an animal analog of RDV. The low-resolution structural match of the RDV outer shell trimer to the HEX conformation of VP7 trimer has led to the proposal that P8 consists of an upper domain of beta-sandwich motif and a lower domain of alpha helices. The less well fit REF conformation of VP7 to the RDV trimer may be due to the differences between VP7 and P8 in the sequence of the hinge region that connects the two domains. The additional mass density and the absence of a known signaling peptide on the surface of the RDV outer shell trimer may be responsible for the different interactions between plants and animal reoviruses.

Amino Acid Sequence↗
PubMed1998

A nuclear matrix protein interacts with the phosphorylated C-terminal domain of RNA polymerase II.

Yeast two-hybrid screening has led to the identification of a family of proteins that interact with the repetitive C-terminal repeat domain (CTD) of RNA polymerase II (A. Yuryev et al., Proc. Natl. Acad. Sci. USA 93:6975-6980, 1996). In addition to serine/arginine-rich SR motifs, the SCAFs (SR-like CTD-associated factors) contain discrete CTD-interacting domains. In this paper, we show that the CTD-interacting domain of SCAF8 specifically binds CTD molecules phosphorylated on serines 2 and 5 of the consensus sequence Tyr1Ser2Pro3Thr4Ser5Pro6Ser7. In addition, we demonstrate that SCAF8 associates with hyperphosphorylated but not with hypophosphorylated RNA polymerase II in vitro and in vivo. This result suggests that SCAF8 is not present in preinitiation complexes but rather associates with elongating RNA polymerase II. Immunolocalization studies show that SCAF8 is present in granular nuclear foci which correspond to sites of active transcription. We also provide evidence that SCAF8 foci are associated with the nuclear matrix. A fraction of these sites overlap with a subset of larger nuclear speckles containing phosphorylated polymerase II. Taken together, our results indicate a possible role for SCAF8 in linking transcription and pre-mRNA processing.

Amino Acid Sequence↗
PubMed1998

Protective effect of anisodamine on reperfusion injury of skeletal muscles in rabbit.

Anisodamine is an alkaloid isolated from a Chinese plant, which was subsequently synthesized. Its chemical structure is similar to atropine. It inhibits cholinergic nerve function, improves microcirculation, and was reported to have a protective effect on reperfusion injury in various organs. We used anisodamine in a rabbit model with ischemia and reperfusion injury of hind limb muscles. We evaluated its effect on skeletal muscle cells, using transmission electron microscopy, and analyzed lipid peroxidation by measuring malondialdehyde and lactate dehydrogenase blood concentrations. We found that malondialdehyde and lactate dehydrogenase concentrations after 1 hour of reperfusion were lower in animals treated with anisodamine than in controls. Damage to membrane structures and myofilaments in muscle cells was less severe after anisodamine treatment. Our findings indicate that anisodamine protects skeletal muscles with ischemia and reperfusion injury.

Animals↗
PubMed1998

[Plasmid profile typing of Salmonella typhimurium and its distribution in some provinces and cities of China].

OBJECTIVE: To study the relationship between the infection and prevalence of Salmonella typhimurium. METHODS: From 1980 to 1995, when Salmonella typhimurium infection was prevalent in north and south China, a total of 2,655 isolates of Salmonella typhimurium were collected from 19 provinces, municipalities, and autonomous regions and Hong Kong Special Administrative Region for plasmid profile analysis. The profiles consisting of some small plamids were recorded with capital letters A to J, and the profile which was free from small plasmid was recorded with capital letter O. Large plasmid in molecular weights of 140-20 Mdal showing in profiles was recorded with Arabic numerals 9 to 0 respectively. Having two or more than two large plasmids, the profile was recorded with two or more Arabic numerals. RESULTS: The 2,655 strains were divided into 11 plasmid profile groups and 168 plasmid profile types. Of 52 plasmid profile types frequently isolated, plasmid profile type O 4 was distributed extensively in 16 provinces, municipalities, and autonomous rehions and Hong Kong. Plasmid profile type O 5 was isolated in 5 provinces and Hong Kong, mostly in Jiangxi and Hubei. Plasmid profile type J 4 was isolated in 7 provinces, municipalities and autonomous regions, mostly in Jiangxi. Five plasmid profile types of Group A caused a big prevalence of nosocomial infection in Henan. Type A 6 was also isolated in Xinjiang and Anhui. Six plasmid profile types of Group E were prevalent in Xinjiang predominantely, three types caused nosocomial infection in Shanghai, type E 82 caused nosocomial infection and food poisoning in Liaoning. Type F 4 was isolated in 4 provinces, mostly in jiangxi and Fujian. Many plasmid profile types were prevalent local. Types B 5, BCEG 60, BE 6, B' 0 G 6, G 5 and EG 6 were prevalent in Jiangxi, Types IF'4, IF'H40 and F 9864 were prevalent in Sandong, Type IF'4 was also isolated in Jiangsu and Hubei, Type IF 40 in Anhui, Type BH 6 in Huibei, and Type EH 5 in Fujian. CONCLUSION: Plasmid profile analysis showed the same types in the prevance but different plasmid profiles in different provinces.

China↗
PubMed1998

[Effects of cadmium chloride on the function of peritoneal macrophage in mice].

OBJECTIVE: To study the effects of cadmium on macrophage function. METHODS: Many indicators, such as phagocytic function, abilities to produce nitrous oxide and hydrogen peroxide, in mice were determined 14 days after they were administered continuously with 0.3, 0.6 and 1.2 mg/kg cadmiuCell count decreased in the mouse peritoneal lavage with the effects of cadmium chloride, with a significant difference, as compared with the control group. Phagocytic function of macrophage was inhibited significantly, with inhibition rates of 21.8%, 39.9% and 44.4%, respectively for various doses of cadmium, in a dose-response pattern. The ability of microphage to produce nitrous oxide was significantly inhibited, also, with 61.90 +/- 27.83, 36.67 +/- 23.86, 46.60 +/- 13.33 mumol/L, respectively, as compared with 76.10 +/- 14.22 mumol/L in the control group. The ability of microphage to produce O2.- was obviously inhibited by three different doses of cadmium, showing a dose-response relationship (r = 0.9790). The ability of microphage to produce hydrogen peroxide was inhibited only at a dose of 1.2 mg/kg of cadmium, with a significant difference as compared with the control group. There was a dose-response relationship between cadmium and production of hydrogen peroxide, with a coefficient of regression (r) of -0.9847. CONCLUSION: Cadmium chloride, at the doses of 0.3, 0.6 and 1.2 mg/kg, could inhibit the phagocytic function of microphage, and the production of biological molecules, such as nitrous oxide, O2.- and hydrogen peroxide. It indicated that cadmium chloride could directly affect the transmission of antigen and non-specific defence function of macrophage.

Animals↗
PubMed1998

[A pathological study on the autotransplantation of monkey's cervical sympathetic ganglion into brain for the treatment of Parkinson's disease].

OBJECTIVE: In order to find out evidences in explicating whether the transplanted ganglion cells can be kept surviving longer in the brain and to find out an ideal transplantation way for the surgical treatment of Parkinson's disease. METHODS: Cervical sympathetic ganglions autotransplantation into the caudate nuclei of the brain in 9 rhesus monkeys known to have the symptoms and signs of the Parkinson's disease beforehand induced by using 1-methy1-4-phen-1, 2, 3, 6-tetrahydropynidne (MPTP) and in addition, muscle tendon tissue was also grafted for comparison. The experimental animals were followed up for 2 years. All the specimens taken were processed and prepared in continuous frozen sections for H & E, glyoxlyic acid induced dopamine fluorescence and immunochemistry stainings including anti-chromogranin A, synaptophysin, neurofilament, NSE, GFAP as markers. RESULTS: Two years after the autotransplantation operation, there were still surviving ganglion cells left in the caudate nuclei. The grafted ganglion cells were connected by the neurodendrites with the brain tissue which showed dopamine fluorescence positive and also had expression of chromogramin A, synaptophysin and neurofilaments. CONCLUSIONS: The grafted cells survived in the brain over 2 years. It's considered that the sympathetic ganglion is the first choice in comparing with other tissues as the graft for the surgical treatment of Parkinson's disease. Continuous frozen sections accompanying with inducing fluorescence and immunohistochemistry staining are seemed reliable as the parameters in checking the result after neural transplantation.

Animals↗
PubMed1998

[The effect of intracoronal bleaching on cervical periodontium of dogs]

OBJECTIVE:To study the effects of two intracoronal bleaching techniques on dog's cervical periodontium.METHODS: The experimental animal modles of intracoronal bleaching were established and pathological slides were made. The histological changes of dogs' periodontium were examined by means of light micro-scope. RESULTS: A year following intracoronal bleaching,the group received thermocatalytic bleaching showed:(1)resorption of cementum or dentine;(2)ankylosis,(3)infiltratin of substantial inflamatory cells into resorption areas.The group received walking bleaching showed:(1)localized resorption of alveolar bone;(2)lacuna-shaped resorption of cementum. CONCLUSION: Whether heated or not,intracoronal bleaching with bleaching with bleaching agent including 30% hydrogen peroxide may innitiate external cervical resorption of dog's teeth.

Journal Article↗
PubMed1998

[Study of the effect of zine-oxide phosphorate base on preventing leakage in intracoronal bleaching]

OBJECTIVE: To study the effect of zine-oxide phosphorate base on preventing hydrogen peroxide leakage in intracoronal bleaching. METHODS: Intracoronal bleaching was given to exsomatized teeth,and the amounts of penetrated hydrogen peroxide was determind by spectro-photo-metry. RESULTS: Placement of a zinc oxide phosphorat protective base at CEJ level decreased hydrogen peroxide. penetration dramatically. CONCLUSION: The zine oxide phosphorate base was a kind of effective measure to prevent post-bleaching external cervical ersorption.

Journal Article↗
PubMed1998

Healing of the anterior attachment of the rabbit meniscus to bone.

In a rabbit model the healing process of the anterior attachment of the medical meniscus was observed during the first 12 weeks after sharp transection and refixation in a tibial bone channel. Evaluations of the healing tissue were histologic analysis, application of immunohistochemical methods to show collagen types and nerve regeneration, and mechanical load to failure tests. Secondary changes to knee joint cartilage, as signs of eventual dysfunction of the refixed meniscus, were evaluated by analysis of proteoglycan fragment concentration in joint fluid and histologic analysis of knee joint articular cartilage and synovium. The healing tissue between the refixed attachment and bone matured from highly cellular, nonspecific granulation tissue at 1 week, to bone, fibrocartilaginous, and fibrous tissues, which at some sites developed an insertion specific tissue arrangement within a 12-week period. However, the irregular interface between the fibrocartilaginous tissue and the underlying bone, which is typical for a normal insertion, was not reestablished. Labeling for collagen Types I and II in the newly formed insertion did not return to normal. In addition a few collagen fibers connected the refixed attachment tissue to bone. New bone formation turned the initially cancellous bone tunnel walls into more solid cortical bone. However, new bone formation did not fill the distal part of the channel. The refixed meniscal attachment underwent necrosis and was revitalized by cell ingrowth from the periphery. Nerve fibers were found in the newly formed insertion by 12 weeks. The failure load at tensile testing never reached more than 20% that of a normal attachment. Degeneration of articular cartilage and increased proteoglycan fragment in the joint fluid were common after this procedure. These data suggest that, despite the focal appearance of insertion specific tissues and healing of collagen fibers to bone, the tissue architecture of a normal meniscal insertion and a normal meniscal joint protective function were not reestablished.

Animals↗
PubMed1998

The new paradigm: integrating genomic function and nuclear architecture.

A new view of the cell nucleus is emerging based on the functional dynamics of nuclear architecture. The striking structural preservation of a variety of genomic processes on the nuclear matrix provides an important approach for correlating nuclear form and function. In situ labeling coupled with three-dimensional microscopy and computer imaging techniques shows that DNA replication and transcription sites are organized into higher-order units, or "zones," in the cell nucleus. The dynamic interplay and "re-zoning" of replication and transcription regions during the cell cycle may form the structural basis for the elaborate global coordination of replicational and transcriptional programs in the mammalian cell.

Animals↗
PubMed1997

Molecular cloning of a putative tetrodotoxin-resistant sodium channel from dog nodose ganglion neurons.

Voltage-gated tetrodotoxin (TTX)-resistant sodium channels present in primary sensory neurons may be responsible for the excitability of nociceptors, and may underlie pain and tenderness associated with tissue injury and inflammation. Here, we report the cloning of a putative sodium channel (NaNG) from dog nodose ganglia. The sequence of the full-length cDNA predicts an open reading frame of 5886 nucleotides encoding a protein of 1962 amino acids. The predicted protein shows 82.3% identity with the recently discovered TTX-resistant sodium channel (SNS/PN3). In the TTX-binding site, a serine appears as in TTX-resistant SNS/PN3, instead of Cys (as in TTX-insensitive cardiac channels) and Tyr/Phe (as in TTX-sensitive sodium channels). Coupled transcription and translation of full-length cDNA produced a 220-kDa protein; based on Northern blot and RT-PCR analysis, its expression is restricted to nodose ganglia, and not present in cortex, hippocampus, cerebellum, liver, heart or skeletal muscle. We propose that NaNG might be a new member of the TTX-resistant sodium channel family expressed in sensory neurons.

Amino Acid Sequence↗
PubMed1997

Maturation-dependent repair of untreated osteochondral defects in the rabbit knee joint.

Repair of untreated full-thickness cartilage defects in the medial femoral knee condyle was studied in 17 young, 21 adolescent, and 19 adult rabbits. At 6 weeks, the defect was completely filled by tissue regeneration in all young and adolescent animals, but in only few of the adults (p < 0.05). The morphology of all repairs improved from fibrous tissue to hyaline-like cartilage over time (p < 0.05), but at 3 and 6 weeks, the repair tissue in young and adolescent rabbits was more cartilage-like than in the adults (p < 0.05). In addition, bonding of the repair tissue to the adjacent cartilage was better in the young and adolescent than in the adult animals (p < 0.05). At 12 weeks, subchondral bone had formed in some young and adolescent repairs, but in no case in the adults. None of the repairs showed normal cartilage appearance, but formation of hyaline-like cartilage was common at 12 weeks. Irrespective of age or observation time, the repair site showed decreased stiffness and larger strain values compared to adjacent or control cartilage (p < 0.001) with no tendency for improvement over time. Younger animals showed a faster filling of the defect and an earlier specialization of the repair tissue than adult animals, but the mechanical quality of the regenerated tissue remained inferior to normal.

Aging↗
PubMed1997

Transferrin receptor recycling in rat hepatocytes is regulated by protein phosphatase 2A, possibly through effects on microtubule-dependent transport.

To understand the regulation of receptor-mediated endocytosis in hepatocytes, we have used two specific inhibitors of serine-threonine protein phosphatases (PP), microcystin (MCYST) and okadaic acid (OKA) as probes to alter protein phosphorylation in hepatocytes. We have then examined the impact of these changes on the specific binding and uptake of transferrin (Tf) in hepatocytes. The measurement of PP activity in hepatocyte lysates showed that OKA and MCYST shared a common inhibition of protein phosphatase 2A (PP2A). Our results showed that both OKA (250 nmol/L) and MCYST (500 nmol/L) significantly reduced Tf uptake at steady state (P < or = .05). The measurement of Tf internalization after 15 minutes in protein phosphatase inhibitor-pretreated cells revealed that the initial uptake was also significantly reduced. Binding studies showed that pretreatment with either of the phosphatase inhibitors did not result in significant changes in the K(d) for Tf binding to transferrin receptor (TfR). Additionally, no significant changes in the number of TfR in the plasma membrane were observed in phosphatase inhibitor-pretreated cells. The treatment of hepatocytes with nocodazole (NOC), which results in microtubule disassembly and inhibition of microtubule-based vesicle transport, caused comparable reductions in initial and steady state levels of transferrin accumulation. The changes in transferrin accumulation by both phosphatase inhibitors and nocodazole were accompanied by redistribution of the microtubule-anchored Golgi apparatus and lysosomal network from the perinuclear region to the cell periphery. Our data show that the regulation of Tf uptake by receptor-mediated endocytosis is mediated by PP2A and additionally may occur through regulation of microtubule-based vesicle transport.

Animals↗
PubMed1997

Cholinergic stimulation of lacrimal acinar cells promotes redistribution of membrane-associated kinesin and the secretory protein, beta-hexosaminidase, and increases kinesin motor activity.

The role of the microtubule-based motor, kinesin, in membrane trafficking has been investigated in resting and stimulated acinar cells from rabbit lacrimal gland, a cholinergically controlled secretory tissue. Microtubule-dependent motors from extracts of control and carbachol-treated acini were isolated by microtubule-affinity purification and their activity was determined using a video-enhanced differential interference contrast microscopy assay for microtubule gliding. The observation that carbachol treatment resulted in a 2.2-fold stimulation of the frequency of GTP-dependent microtubule gliding in fractions isolated by microtubule-affinity purification and GTP release suggested that kinesin was a target of carbachol-induced stimulation. Resolution of membranes from resting cells by fractionation on a sorbitol density gradient followed by partitioning analysis in a dextran-polyethyleneglycol two-phase system revealed that membrane-associated kinesin codistributed with Golgi-derived membranes, a post-Golgi secretory compartment designated Hex1, membranes from a trans Golgi network-like compartment, endoplasmic reticulum and a group of putative lysosomal membranes containing cathepsin B. Comparable fractionation of carbachol-treated acini showed that stimulation caused redistributions of membrane-associated kinesin, the secretory enzyme beta-hexosaminidase, and galactosyltransferase that appeared to reflect both a reorganization within the Golgi complex and a return of material to the Golgi complex from the secretory pathway. Our findings that carbachol promotes activation of lacrimal acinar kinesin as well as major shifts in kinesin-membrane association within the secretory pathway suggests that kinesin plays a major role in secretory vesicle assembly, apical secretion, and/or secretory vesicle membrane recycling in the lacrimal gland.

Animals↗