Search PubMed⌕ Search

Biomedical subjects

W Wei

Publications and source records attributed to W Wei.

At least 109 records · Page 6Linked to original sources
PubMed1999

Parathyroid hormone and mechanical usage have a synergistic effect in rat tibial diaphyseal cortical bone.

Previous reports showed that bone mass and architecture only partially recovered by remobilization (RM) after immobilization (IM)-induced osteopenia, and that parathyroid hormone (PTH) had an anabolic effect on the skeleton. The aim of this study was to determine whether low doses of PTH could restore IM-induced cortical bone loss and whether a combination of PTH plus loading (RM) treatment would be more effective than the PTH in unloaded (IM) limbs. One hundred and sixty 6-month-old rats were divided into aging and IM groups. The right hindlimb of the rat was immobilized by elastic bandage for 18 weeks, and then groups of rats were either kept IM or RM and treated with 30 microgram or 80 microgram of hPTH(1-38)/kg/day for 2, 10, and 20 weeks. Fluorescent-labeled, undecalcified cross-sections of right tibial shafts were studied. We found that RM for 20 weeks after 18 weeks of IM only partially recovered IM-induced muscle weight loss and PTH had no effect on muscle weight in either IM or RM limbs; that RM for 20 weeks after 18 weeks of IM partially restored some minimal cortical width by stimulating periosteal and endocortical bone formation and decreasing endocortical resorption; that PTH treatment of IM limbs completely restored IM-induced cortical bone loss and added extra bone by stimulating bone formation indices on all bone surfaces and depressing bone resorption on endocortical surface; that PTH treatment of RM limbs produced similar anabolic effects as in IM limbs with 30 microgram/kg/day dose but the 80 microgram/kg/day dose-treated limbs had a higher periosteal bone formation rate, which created a larger cross-sectional area, more cortical bone area, and a thicker cortex than the same dose treated IM limbs; and that PTH 80 microgram/kg/day treatment produced more anabolic effect than the 30 microgram/kg/day in both IM and RM limbs. We concluded that reloading the hindlimb by RM after long-term IM could not recover the cortical bone mass. PTH at employed doses was able to completely restore IM-induced cortical bone loss, and this effect was independent of mechanical stimulation. However, when PTH was combined with mechanical loading (RM), a synergistic anabolic effect on periosteal bone formation occurred which increased the cross sectional area that can increase bone strength.

Aging↗
PubMed1999

A study on the methods for early serological diagnosis of leprosy and their potential use.

This is a serial study. In this series we have established 12 methods for the early serological diagnosis of leprosy, including the FLA-ABS test, ELISAs with artificial products (ND-O-, ND-P-, NT-O-, NT-P-BSA; PGL-I, whole M. leprae and M. smegmatis), monoclonal antibody specific binding assay (McAb/SBA), latex agglutination test (LAT), and MLPA. These methods were compared with each other on a large scale in leprosy patients and in the field. The results indicate that 1) Excellent results were obtained when ELISAs were conducted with skim milk or egg albumin as the blocking agent and by using blood from earlobes instead of from venipuncture. 2) According to the four "S" standard (sensitivity, specificity, simplicity and speed), among the 12 methods the ND-O-BSA-ELISA (ND-ELISA) is the best and the MLPA is more suitable for use in the field because it is simple and rapid. 3) In the ND-ELISA, the increase or decrease of the OD value has a positive correlation with the BI, and the order of positive rates was a) in various types of leprosy: LL > BL > BB > BT > TT; b) in household contacts (HC), random population (RP), normal controls in endemic areas (ENC) and normal controls in nonendemic areas (NNC): HC > RP > ENC > NNC. 4) In a population with subclinical M. leprae infection, the highest risk group was between the ages of 15 and 25 and had an increase or a persistence of high OD values prior to onset of disease. 5) OD values gradually decreased over time following treatment and these declines paralleled declines in the BI. 6) In cases cured with dapsone therapy, there was an increase or a persistence of high OD values in ND-ELISA prior to the onset of a leprosy relapse. In conclusion, we have compared and evaluated 12 immuno-assays and have shown that the ND-ELISA is the most practical one for use in investigating sero-immunological epidemiology, subclinical infection with M. leprae, early detection of disease, monitoring of antimicrobial therapy, and even for the prediction of leprosy relapse.

Antibodies, Bacterial↗
PubMed1999

[Study on expression of apoptosis related genes in non-small cell carcinoma].

OBJECTIVE: To study the relationship between the expression of apoptosis related genes in the tissue of non-small cell lung carcinoma (NSCLC) and clinicopathology in the tumor. METHODS: The expression of bcl-2, bax, Fas and FasL were detected with immunohistochemistry method in 45 cases of NSCLC. RESULTS: 23 (51%) cases of NSCLC were bcl-2 positive, 38 (84%) were bax positive (P < 0.01), and there was no significant correlation between the expression of bcl-2 and bax protein, but a positive relationship was found between the expression of Fas and FasL (P < 0.01). The positive rate of bcl-2 expression decreased in advanced stages of NSCLC(P < 0.05), the bax expression was lower in cases with poor cell differentiation (P < 0.05), and the FasL expression was higher in adenocarcinoma (P < 0.01). The simultaneous expression of bcl-2 and bax protein was closely correlated with TNM stages (P < 0.05), the differences of bcl-2 protein expression alone in NSCLC with cell differentiation were statistically significant (P = 0.033). CONCLUSIONS: Both bcl-2, bax, Fas and FasL may involve in the regulation of apoptosis and may play an important role in the occurrence and progression of NSCLC.

Adult↗
PubMed1999

[Operative results of tethered cord syndrome].

OBJECTIVE: To evaluate the treatment results of 22 cases of spinal tethered cord syndrome (TCS) using microneurosurgical technique. METHODS: Form 1994 to 1997, 22 cases of TCS verified by MRI were treated. All patients'tips of conus were below L(2) vertebra shown by MRI. In this group, 4 cases had lipid disease in the sacral canal, 5 piloidal sinus, and 13 thick filum. The patients were operated on using linear incision. The incision included the terminal conus and the whole filum. Under the microscope, the adhesions of the caudal equine were separated and the filum was found out. The caudal equine was well combed. Lipoma and piloidal sinus were removed totally or partially. Loosening the spinal conus and repairing the dural matter prevented re-adhesion and re-tether. RESULTS: Follow-up (0.5 - 3 years) showed that all of the patients were recovered in different levels. CONCLUSIONS: TCS should be found as early as possible and treated under the microsurgical technique.

Adolescent↗
PubMed1999

[A study on ocular anterior segment structure after scleral buckling surgery for retinal detachment].

OBJECTIVE: To study the changes of the ocular anterior segment structure and the mechanism of angle-closure glaucoma after scleral buckling surgery. METHOD: 30 patients (33 eyes) who suffered from rhegmatogenous retinal detachment had been observed before and 3 - 7 days after the surgery. The quantitative measurement of the ocular anterior segment structure in vivo had been done by ultrasound biomicroscopy (UBM). The results were statistically analyzed. RESULTS: There was one eye with split-like ciliary body detachment before the surgery, there were 11 eyes with ciliary body detachment (33.3%) and the ciliary body was thickened and edematous after surgery. Before the surgery the thickness of the ciliary body was (821.32 +/- 64.21) microm and after the surgery it was (945.27 +/- 104.16) microm, the difference being statistically significant, P < 0.05. Parameters reflecting the changes of the anterior chamber angle before and after surgery were as follows: the anterior chamber angle became narrower, the angle open distance 500 decreased, the trabecular-iris angle decreased in degree, the angle of the scleral lateral side and iris long axis decreased, and all these differences were statistically significant, P < 0.05, but the depth of the central anterior chamber had no obvious change, and the difference was not statistically significant, P > 0.05. CONCLUSIONS: Ciliary body detachment and edema are often found after scleral buckling surgery, and post-operatively the central anterior chamber depth has no obvious change; ciliary body detachment and edema perhaps are related to the angle-closure glaucoma after the surgery.

Adolescent↗
PubMed1999

[Optical coherence tomography of macular holes].

OBJECTIVE: To study the characteristics and clinical application value of the optical coherence tomography (OCT) of macular holes. METHOD: A total of 35 patients with the clinical diagnosis of macular hole were examined with OCT between September and December 1998. OCT imaging was conducted through a dilated pupil, and the OCT images were analyzed and measured. RESULTS: Of the 35 patients examined with OCT, there were pseudohole and epimacular membrane in one eye, vitreofoveal traction in one eye, macular holes in 36 eyes, and 3 patients had macular hole in bilateral eyes. In 4 eyes, there were partial-thickness macular holes, and the defect of partial thickness of neural epithelium in the fovea without halo of retinal detachment was shown in the OCT image. In 32 eyes, there were full-thickness holes; the OCT displayed complete losing of the whole thickness of the neural epithelium in the fovea, sharp edge of the hole and the halo of retinal detachment around the hole. Sometimes nonreflective cavities could be seen within the retina, and the retinal thickness around the hole was increased. According to Gass stage classification of macular hole, there were 2 eyes with impending hole, 3 eyes in stage 2, 15 eyes in stage 3 and 6 eyes in stage 4. 4 eyes underwent vitrectomy. The OCT imaging after the surgery demonstrated the closure of hole and the disappearance of halo surrounding the hole. Through quantitative measurement, the diameter of the hole was (565.88 +/- 40.35) microm, the diameter of the halo was (1,338.76 +/- 147.57) microm, and the retinal thickness surrounding the hole was (391.87 +/- 18.97) microm. The sizes of the hole and the halo and the retinal thickness around the hole were correlated with the vision. CONCLUSION: OCT is a novel noninvasive, noncontact imaging technique. It is helpful in the diagnosis and differential diagnosis of the macular hole; the progress of the hole can be quantitatively estimated, and it is also helpful in selection of operation and assessment of operative therapeutic effects.

Adult↗
PubMed1999

[Relationship between the expression of p53 and C-erbB-2 oncoproteins and biologic behaviors of human mucoepidermal carcinoma of salivary gland]

OBJECTIVE:To study the relationship between the expression of p53 and c-erbB-2 proteins and biologic behaviors of human mucoepidermal carcinoma.METHODS:The expressions of oncogene proteins p53 and c-erbB-2 in 32 cases of human mucoepidermal carcinomas were investigated with microwave immunohistochemistry.RESULTS:p53 and c-erbB-2 oncoproteins in duct epithelial cells around cancer tissues were 10.0% and 15.0%,respectively,but those in the acinar cells affiliated with the salivary gland ducts were negative. The positive rates of p53 oncoprotein and c-erbB-2 oncoprotein in mucoepidermal carcinoma were 40.6% and 46.9%,respectively. Both p53 and c-erbB-2 oncoproteins were expressed in mucous cells,epidermoid cells and intermediate cells of mucoepidermal carcinoma. The expression of p53 and c-erbB-2 oncoproteins in human mucoepidermal carcinoma tissues were related to histological patterns,differentiation degree of cancer and tumor recurrence (P<0.01).CONCLUSION:This study suggested that both p53 and c-erbB-2 on coproteins,as the markers for differentiation of cancer,might be useful in screening progress and evaluating prognosis of patients with mucoepidermal carcinoma.

Journal Article↗
PubMed1998

Dissociation among in vitro telomerase activity, telomere maintenance, and cellular immortalization.

The immortalization of human cells is a critical step during tumorigenesis. In vitro, normal human somatic cells must overcome two proliferative blockades, senescence and crisis, to become immortal. Transformation with viral oncogenes extends the life span of human cells beyond senescence. Such transformed cells eventually succumb to crisis, a period of widespread cellular death that has been proposed to be the result of telomeric shortening. We now show that ectopic expression of the telomerase catalytic subunit (human telomerase reverse transcriptase or hTERT) and subsequent activation of telomerase can allow postsenescent cells to proliferate beyond crisis, the last known proliferative blockade to cellular immortality. Moreover, we demonstrate that alteration of the carboxyl terminus of human telomerase reverse transcriptase does not affect telomerase enzymatic activity but impedes the ability of this enzyme to maintain telomeres. Telomerase-positive cells expressing this mutant enzyme fail to undergo immortalization, further tightening the connection between telomere maintenance and immortalization.

Cell Division↗
PubMed1998

The hepatitis B virus X protein is a co-activator of activated transcription that modulates the transcription machinery and distal binding activators.

Hepatitis B virus X protein (HBx) transactivates viral and cellular genes through a wide variety of cis-elements, but the mechanism has not been well elucidated. Evidence for nuclear events in HBx transactivation has been reported. Here we examine the role of HBx in modulation of transcription with a transient transfection system and an in vitro transcription assay. Reporters bearing Gal4-binding sites were applied to avoid the effects of endogenous transcription factors with or without signaling processes. The Gal4-DNA binding domain fused form of HBx exhibited no effect on Gal4-responsive reporters. However, HBx augmented activated transcription by transcriptional activators, suggesting HBx retains a co-activator but not a transcriptional activator function. The functional domain for co-activation was the same as that for HBx transactivation, and the transcription factor IIB- and RNA polymerase II subunit 5-interacting sites of HBx, which were critical for HBx transactivation, were shown to be crucial for the co-activation function. Importantly, HBx stimulated transcription on templates bearing the X responsive elements in vitro with endogenous activators. These results imply that HBx acts as a co-activator that modulates transcriptional machinery and distal-binding activators, which may explain one of the mechanisms of transactivation by HBx when localized in nuclei.

DNA-Directed RNA Polymerases↗
PubMed1998

Variability of persisting MHV RNA sequences constituting immune and replication-relevant domains.

Survivors of acute infection with the neurotropic JHM strain of mouse hepatitis virus develop a persistent infection of the central nervous system associated with chronic ongoing demyelination. Persistence is characterized by viral RNA in the absence of infectious virus. To associate persistence with possible immune evasion and/or replication defects, viral RNA from brains of acutely and persistently infected mice was examined for mutations by reverse transcriptase-PCR. Sequences analyzed included the encapsidation sequence (ECS), the transmembrane domains of the matrix (M) protein, and a cytotoxic T cell (CTL) epitope within the nucleocapsid (N) protein. The ECS, present only on genomic RNA, revealed minimal variability and was detected out to 120 days postinfection, suggesting low levels of replication. The M gene sequence also remained stable during persistence despite random mutations during the acute phase. Although the N gene sequence exhibited the greatest diversity, mutations were random and not selected for during persistence. A single exception was detected comprising a prominent Pro to Ser substitution in a region of N not associated with any known regulatory or immune function. Of the N gene mutations found within the CTL epitope in responder mice (H-2d), one resulted in reduced CTL recognition with no evidence of antagonist activity. However, this mutation was also detected in nonresponder mice (H-2b), suggesting that escape variants arising from CTL pressure play no role in establishing persistence in immunocompetent hosts infected as adults.

Animals↗
PubMed1998

Factors associated with the mammalian RNA polymerase II holoenzyme.

The RNA polymerase II (Pol II) holoenzyme in yeast is an essential transcriptional regulatory complex which has been defined by genetic and biochemical approaches. The mammalian counterpart to this complex, however, is less well defined. Experiments herein demonstrate that, along with Pol II and SRB proteins, proteins associated with transcriptional regulation as cofactors are associated with the Pol II holoenzyme. Earlier experiments have demonstrated that the breast cancer-associated tumor suppressor BRCA1 and the CREB binding protein (CBP) were associated with the holoenzyme complex. The protein related to CBP, the E1A-associated p300 protein, is shown in these experiments to be associated with the holoenzyme complex as well as the BRG1 subunit of the chromatin remodeling SWI/SNF complex. Importantly, the Pol II holoenzyme complex does not contain some factors previously reported as stoichiometric components of the holoenzyme complex, most notably the proteins which function in repair of damaged DNA, such as PCNA, RFC and RPA. The presence of the p300 coactivator and the chromatin-modifying BRG1 protein support a role for the Pol II holoenzyme as a key target for regulation by enhancer binding proteins.

BRCA1 Protein↗
PubMed1998

Apoptosis of JHMV-specific CTL in the CNS in the absence of CD4+ T cells.

The role of CD4+ T cells in altering the activity of cytotoxic T lymphocytes (CTL) during infection of the central nervous system (CNS) by the neuroptropic JHMV strain of mouse hepatitis virus was examined. Adoptive transfer of in vitro activated CTL into CD4-depleted and control recipients showed that CTL were not effective in reducing JHMV replication within the CNS. The distribution of CD4+ and CD8+ T cells within the CNS during JHMV infection showed that the CD4+ T cells remained in perivascular and subarachnoid spaces and few entered the parenchyma. By contrast approximately half of the CD8+ T cells entered the parenchyma. In CD4-depleted mice the trafficking of CD8+ T cells was not inhibited; however, the majority of the cells were found to be apoptotic. These data suggested that CD4+ T cells were not required for CTL induction but were required for the maintenance of CTL viability. The limited role of CD4+ T cells in CTL induction was confirmed by comparison of CTL activity from CD4-depleted and control mice.

Adoptive Transfer↗
PubMed1998

Effect of SJAMP on human platelet cytoplasmic Ca2+.

Using the method of dual-wavelength measurement of platelet [Ca2+]i and Fura-2 as the Ca2+ fluorophore probe, we measured the effect of acidic Mucopolysaccharide from Sticopus Japonicus Selenka (SJAMP) on platelet [Ca2+]i. The results showed that the most significant increase in platelets [Ca2+]i was seen when the concentration of SJAMP was 100 micrograms/ml and the elevation of normal platelet [Ca2+]i was 93.96 +/- 10.24 nmol/L (n = 10). In the presence of extracellular Ca2+ (1 mmol/L), the magnitude of platelet [Ca2+]i response to SJAMP was increased and the [Ca2+]i could reach 116.72 +/- 10.66 nmol/L (n = 10). On the other hand, the magnitude of increased platelet [Ca2+]i induced by SJAMP was smaller and the duration of [Ca2+]i reaching the highest level was longer when compared with other platelet aggregation agents. In the mean time, if platelets were first incubated with cyclooxygenase inhibitor, the rise of [Ca2+]i evoked by SJAMP was inhibited. The results indicated that the mechanism of the rise of [Ca2+]i induced by SJAMP might be dependent upon the generation of prostaglandin endoperoxides and(or) TXA2.

Animals↗
PubMed1998

Variations and clinical significance of coagulation and fibrinolysis parameters in patients with diabetes mellitus.

We observed the changes of parameters of coagulation and fibrinolytic system in order to understand the clinical implication of these variations in type II diabetic patients. Subjects consisted of 22 patients with type II diabetes mellitus and 25 healthy controls. Compared with the control, activated partial thromboplastin time, prothrombin time were shortened in the patients. The diabetic subjects also displayed higher levels of D-dimer, serum fibrin degradation products, median concentrations of fibrinogen (3.99 vs 2.96 g/L, P < 0.01) and von Willebrand factor (149% vs 87%, P < 0.01). Levels of antithrombin III activity or antigen were not different from control values. Simple linear regression analysis revealed a negative correlation between antithrombin III activity and fast blood glucose. Diabetic patients with vascular complications had significantly higher levels of fibrinogen and D-dimer than those without diabetic angiopathy. Our data demonstrated that patients with type II diabetes mellitus had a hypercoagulable state. We believed the activation of coagulation might contribute to the vascular complications in diabetics.

Adult↗
PubMed1998

Study on the hypercoagulable state in patients with angina and myocardial infarction.

The molecular markers of platelet activation, coagulation and fibrinolysis were detected in 60 cases of coronary heart disease (CHD), including 15 cases of stable angina (SA), 21 cases of unstable angina (UA) and 24 cases of acute myocardial infarction (AMI). The results showed that the platelet granule membrane protein 140 (GMP-140) level increased obviously in CHD groups compared with normal control, suggesting that platelet activation existed in CHD. Prothrombin fragment F1 + 2 and fibrinopeptide A (FPA) were examined to observe the activation of coagulation. No difference was found between SA group and normal controls, while their levels in both UA group and AMI group were significantly higher than in normal control and SA group (both P < 0.05). D-D dimer and alpha 2-plasma inhibitor (alpha 2-PI) were detected to observe fibrinolytic state. The results showed that no difference existed between SA group and normal controls, while both D-D dimer and alpha 2-PI in UA group and AMI group were significantly elevated than those in SA group and normal controls (P < 0.05).

Angina Pectoris↗
PubMed1998

Effect of low HDL combined with hypertriglyceridemia in coronary artery disease patients on PGI2 biological activity in relation to lipid regulating treatment.

The purpose of this study was to investigate the effect of low high-density-lipoprotein (HDL) combined with hypertriglyceridemia in coronary artery disease (CAD) patients on prostaglandin I2 (PGI2) biological activity in relation to lipid regulating treatment. The inhibitory rate of PGI2 on ADP-induced platelet aggregation was used as the index for PGI2 biological activity. Twenty health individuals served as normal controls. CAD group consisted of 20 patients with low HDL combined with hypertriglyceridemia. The results showed that, before the treatment, the stabilizing effect on PGI2 activity decreased significantly in CAD group when compared with the control group (P < 0.01). One month after the treatment, HDL level in CAD group increased significantly and TG level significantly decreased (P < 0.001). The different effect on PGI2 activity was no longer found between CAD group and control group (P > 0.05), further confirming the protecting effect of HDL on PGI2 biological activity. Low HDL is considered as an important risk factor of CAD, therefore, impaired PGI2 biological activity and increased platelet aggregation might be responsible mechanisms. Furthermore, raising HDL level by lipid regulating treatment could restore the protective effect of HDL on PGI2 and might be helpful in the prevention of the acute coronary syndrome.

Coronary Disease↗