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Biomedical subjects

W Wang

Publications and source records attributed to W Wang.

At least 1,063 records · Page 59Linked to original sources
PubMed1997

[Dobutamine technetium-99m-MIBI spect in evaluating the effects of coronary interventional management].

OBJECTIVE: To evaluate the effects of coronary interventional management by dobutamine 99mTc-MIBI single photon emission computed tomography (Dobu-ECT). METHODS: Dobu-ECT was performed in pre- and post-interventional management of 32 patients. Dobutamine was administered intravenously at incremental rates from 5 to 40 micrograms x kg-1.min-1 at 3-minute intervals. At the highest infusion rate, 20 mCi 99mTc-MIBI was injected intravenously, and tomographic imaging was performed after one hour. Rest imagings were taken after 24 hours with a second dose of 99mTc-MIBI. RESULTS: In 32 patients accepting interventional treatment, within 3-6 months follow-up, the results of Dobu-ECT showed a total effectiveness rate of treatment was 68.1%. 27 patients of whose Dobu-ECT showed significant reversible defects before procedure, the effectiveness rate was 77.8% (21/26), 6 still had reversible ischemia within the follow-up period, and restenoses of 5 patients were confirmed by angiography. We also compared the effect of percutaneous transluminal coronary angioplasty (PTCA) with intracoronary stenting using Dobu-ECT. The results showed that intracoronary stenting was more beneficial than PTCA (81.3% vs 43.8%, P < 0.05) CONCLUSION: Dobu-ECT can be used to evaluate the effect of interventional management and detect restenosis after procedure.

Adult↗
PubMed1997

Clinical and biological relevance of flow cytometric determination of P-glycoprotein expression in acute non-lymphocytic leukemia.

OBJECTIVE: To evaluate the characteristics of P-glycoprotein (P-gp) expression of acute non-lymphocytic leukemia (ANLL) at different status and the prognostic and biological features in ANLL at diagnosis. METHODS: Monoclonal antibody UIC2 and indirect immunofluorescence assay by flow cytometry were used to determine P-gp expression of 169 patients with ANLL, including 152 previously untreated, 7 refractory and 10 at remission. RESULTS: P-gp was expressed in 28.9% of the previously untreated ANLL cases and P-gp was lower than that in 71.4% of the refractory cases (P < 0.05). No P-gp expression was found in the patients at remission. For previously untreated AN-LL, P-gp was highly expressed in hybrid acute leukemia (66.7%) and acute monoblastic leukemia (47.4%). P-gp expression was highly associated with surface markers [cluster of differentiation (CD) 34, CD7, CD14, CD42b and CD61] and unfavorable cytogenetic abnormalities. About 23% of P-gp-ANLL obtained complete remission, which was significantly lower than that (76%) in P-gp-cases. CONCLUSIONS: P-gp expression is higher in refractory ANLL cases than that in cases at diagnosis or at remission. P-gp is an index of poor prognosis in adults with ANLL. P-gp+ ANLL cases have unique clinical and biological characteristics.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Clinical, pathologic and genetic studies on mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes.

OBJECTIVE: To study the clinical, pathological and genetic characteristics of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). METHODS: Eight cases of MELAS (6 of them were from 2 families) underwent clinical study, muscle biopsy, autopsy on one patient, brain biopsy on one patient and genetic research. RESULTS: In clinical report the average age of onset was 10-22 years old. Four cases from one family were 3 brothers and their nephew (sister's son). The death age of the three brothers was 16-20 years. Two cases from another family were a brother and a sister. The six patients of the two families showed the typical inherited characters of MELAS. The symptoms were myoclonic epilepsy, stroke-like episodes, paralysis of limbs, progressive mental retardation and neurological deaf. CT showed calcification in globus pallidus and MRI demonstrated clearly the abnormal prolongation of T2-weighed signals that distributed in frontal, parietal, occipital and temporal cortex as multiple focal, cystic and laminar necrotic areas. Pathological studies on brain showed multi-focal, cystic, and laminar or spongy necrotic abnormality primarily in gray matter of frontal, parental, temporal and occipital cortex. Decrease and loss of nerve fibers of the sub-cortical white matters of the lesion areas of cortex and calcification of globus pallidus were also observed. Red ragged fibers (RRF) and abnormal mitochondron were found by muscle biopsies. A point mutation (A-G transition) at nt 4243 in the mitochondrial tRNA Leu (UUR) was confirmed by using PCR and Southern Blot. CONCLUSION: Although great progress has been made in the clinical, pathological and genetic research of MELAS, the pathogenesis of the disease remains further research.

Adolescent↗
PubMed1997

[Study on the molecular epidemiology of diarrhea caused by enterotoxigenic Escherichia coli, using polymerase chain reaction with multiple primer pairs].

A Polymerase Chain Reaction (PCR) method has been developed for detecting Enterotoxigenic Escherichia coli (ETEC). Three different sets of oligonucleotide primer were simultaneously used to amplify the enterotoxin genes of heat-labile (LTh) and heat-stable (STIa and STIb) enterotoxins of ETEC. These primers amplified the 627, 240 or 169 base pair DNA fragments from LTh, STIa and STIb genes of the reference ETEC strains, respectively. Five types of ETEC strains corresponding to the LTh, STIa, STIb, LTh-STIa, or LTh-STIb genotypes were distinguished by a single procedure of PCR, using the mixture of the three sets of primers. There was no cross-reaction with the non-ETEC strains. The lowest detection level was 10 cfu. A total number of 623 stool specimens of diarrheal patients from Shangdong Province induced by E. coli were examined by PCR and the positive rate of ETEC was 40.3%. The results indicated that PCR is a rapid, sensitive and specific method for detecting ETEC.

China↗
PubMed1997

[Ionic mechanism of hyperpolarization induced by glucocorticoid in mammalian neurons].

The rapid membrane actions of glucocorticoid were investigated by intracellular electrical recording from 383 coeliac ganglion neurons of guinea-pig in vitro. Thirty-eight neurons were hyperpolarizaed by 2-12 mV when perfused with 1 mumol/L hydrocortisone 21-hemisuccinate (F-suc), associated with a decrease in input membrane resistance. The hyperpolarization was dose-dependent. Nine neurons were depolarized, and the other 336 neurons were unresponsive. The membrane current was also observed with discontinuous single-electrode voltage clamp technique under perfusion of F-suc in another 43 neurons. In five neurons the current was found outward, but it was inward in one neuron. The hyperpolarization persisted after the elimination of synaptic input by low Ca2+ high Mg2+ perfusion and the suppression of protein synthesis by antinomycin D. The reversal potential of F-suc hyperpolarization is -79 +/- 4.3 mV (n = 5). F-suc induced hyperpolarization and GABA induced depolarization could occur in same neuron. The later action could be blocked by picrotoxin. F-suc induced hyperpolarization could be inhibited by TEA and 4-AP, but not picrotoxin. It is suggested that the F-suc's hyperpoalrization is mediated by potassium channel rather than Cl- channel in the sympathetic ganglion neurons.

Animals↗
PubMed1997

[Spectral analysis of R-R intervals in adolesent persons during mental stress].

In this study, power spectrum analysis of the autoregressive model was used to quantitatively estimate the power spectrum of R-R intervals in adolesent during the state of the mental stress. The power spectrum density of the lower frequency (HF: 0.05-0.15 Hz) and the high frequency (HF: 0.15-0.5 Hz) component were acquired. The results showed that during the mental stress the HF component decreased significantly (P < 0.001) while the LF component increased relatively and the center frequency of the HF increased remarkably (P < 0.001). This suggests that the spectral analysis of heart rate variability (R-R interval) offers an efficient non-invasive method to assess the autonomic nerve activity of cardiovascular system during the stress condition.

Adult↗
PubMed1997

[Screening of Candida albicans fluconazole--resistant mutation strains].

We adopted the method of miminum inhibitary concentration (MIC) assay according to the method recommened by National Committee for Clinical Laboratory Standard (NCCLS), and selected 2 fluconazole--susceptible strains from over 50 strains of Candida albicans which were preserved in our center (these strains were all isolated from clinical patients). The number of the strains are: BMU8945 (MIC value is 0.125 microgram/ml) and BMU8977 (MIC value is 0.25 microgram/ml). In addition, we also picked one strain of ATCC14053 (MIC value is 0.5 microgram/ml) as our research starting strains. After the induction of UV and DES, we obtained nearly 1000 colonies of fluconazole--resistant strains (MIC > 30 micrograms/ml). After subculture, we found that the characterization of drug--resistance of these strains could be inheredited stably.

Antifungal Agents↗
PubMed1997

[Experimental study on porous hydroxyapatite ceramics in repair of skull bone defect of rabbit].

In order to investigate the possibility of porous hydroxyapatite ceramics (HAC) in the repair of skull bone defect, twenty-four rabbits were used. The bone defect model was created by operation to obtain a defect in parietal bone in a size of 1 cm x 1 cm. Filled the defect with HAC and methyl-methacrylate-syrene copolymer (MMAS) to fill the defect as control. At 1st, 2nd and 3rd months after operation, behavior of the rabbits was observed and then these animals were sacrificed and specimens were examined under microscope. Results showed as follows: after operation, behavior of all animals were normal. By histological examination, it was found that in HAC group, there were granulation tissue, fibrous tissue and newly formed vessels grew into the pores and the osteoblasts formed osseous trabeculae. There was no inflammatory cell infiltration. In the MMAS grafted asea, there was formation of fibrous membrane. It suggested that HAC might be a good material for bone substitute in repair of skull bone defect.

Animals↗
PubMed1997

[Analysis of pure titanium implants-bone interface by TOF-SIMS].

In order to study the Titanium-bone interaction and integration mechanism, the titanium implant was implanted in the tibia of 9 Newzealand rabbits, and the Ti-bone interface performed for 1, 3, and 6 months were examined and analyzed by fluorescence microscope and advanced TOF-SIMS techniques. The results showed that Ti-bone tissue was integrated closely in a very reactive manner. Both physical and chemical integration occurred in the Ti-bone interface. The Ti-bone could diffuse into the bone tissue though the diffusion was very limited. It was up to 100 microns in depth during the early period. The diffusion density was high, and later in a smooth distribution. Furthermore, while Ti+ diffused into the bone tissue, other elements such as Ca+, OH-, O-, etc, could also diffuse into titanium in exchange. The growth pattern around the bone tissue was in two fashions, one was implantefugal and the other was implantopetal. In this study, based on the ionic distribution, osmosis and impurity elements distribution, the Ti-bone integration mechanism was discussed at molecular and atomic level.

Animals↗
PubMed1997

[The mediopatellar plica syndrome of knee in 61 cases].

From 1989 to 1996, 61 patients, including 66 knees, aged 8 to 62, were diagnosed as mediopatellar plica syndrome of knee after arthroscopic examination. Twenty-one cases were misdiagnosed as medial meniscal lesions before arthroscopic examination. Fifty-nine patients (64 knees) underwent arthroscopic resection of the plicae and 2 patients underwent opened resection. Fifty-nine cases had an average follow-up of seven months. Fifty cases (54 knees) of them showed excellent and good results.

Adolescent↗
PubMed1997

[Change in nitric oxide contents of knee joint fluid in patients with degenerative osteoarthritis].

The degenerative osteoarthritis (DOA) is a common disease of aged people. But its pathogenesis and mechanism are not very clear. We compared the Nitric Oxide content in knee fluid of DOA with the normal people as matched age. The results indicated that the Nitric oxide has a high concentration in DOA. This suggested that the Nitric Oxide may play an important role in the mechanism of this disease.

Aged↗
PubMed1996

Effects of arenastatin A and its synthetic analogs on microtubule assembly.

Inhibition of microtubule assembly by arenastatin A (1) and five synthetic analogs (3-7) was examined. Arenastatin A and the triamide 6 showed potent and moderately strong inhibitory activities, respectively (IC50; 2.3 microM for 1, 7.8 microM for 6) and also depolymerized preformed microtubules. The other analogs tested showed no activity.

Animals↗
PubMed1996

Mechanical strain-induced proliferation of osteoblastic cells parallels increased TGF-beta 1 mRNA.

It is well known that mechanical stimulation can prompt healing of bone fractures. However, the mechanism involved is less clear. In this study, we found that a 0.17% cyclic, biaxial mechanical strain delivered at 1 Hz increased proliferation of MC3T3-E1 cells, a clonal osteoblastic cell line. Mechanical strain also increased the level of TGF-beta 1 mRNA determined by quantitative reverse transcription/ polymerase chain reaction. Previous reports have shown that neomycin and W-7, which are inhibitors in the inositol phosphate/calmodulin pathway, blocked mechanical strain-induced proliferation of the osteoblast cells. Interestingly, we found that neomycin and W-7 can also block mechanical stimulation-induced elevation of TGF-beta 1 mRNA. Finally, using an antibody which blocked the action of TGF-beta 1, we found that the increased MC3T3-E1 cell proliferation induced by mechanical strain did not depend on the action of TGF-beta 1.

3T3 Cells↗
PubMed1996

Cloning and characterization of the cDNA and gene encoding the gamma-subunit of cGMP-phosphodiesterase in canine retinal rod photoreceptor cells.

Rod photoreceptor cyclic GMP-phosphodiesterase (cGMP-PDE) is one of the key enzymes of the visual phototransduction cascade in the vertebrate retina. The enzyme is composed of alpha- and beta-catalytic subunits and two identical inhibitory gamma-subunits. A defect in any of the subunits may potentially alter the activity of the enzyme, leading to aberration in the visual phototransduction. We have cloned and sequenced both the cDNA and gene for the canine gamma-subunit of cGMP-PDE (PDE gamma). The 952-bp cDNA has a coding region of 261 bp which is very similar to those of the PDE gamma cDNAs from human, mouse and bovine retinas. Among the 87 amino acids encoded by the transcribed region, differences in only three residues located within the first 17 amino acids were identified. The carboxyl terminus of PDE gamma, involved in interaction with the catalytic subunits of cGMP-PDE and the alpha-subunit of transducin, is conserved through evolution. The single polyadenylation signal (AATAAA) present in human and bovine PDE gamma cDNAs is replaced by AGTAAA in the canine sequence. The canine gene (2.8 kb) consists of four exons and is much smaller than the human gene (6 kb). The larger size of the human gene is primarily due to the presence of AluI repetitive elements in its first two introns.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1996

The evidence for the incorporation of fulvic acid into the bone and cartilage of rats.

In animal testing, abdominal injection of commercial fulvic acid (FA) to Wistar rats resulted in the coloration of the bone. Free radical signal was detected by ESR spectra of the bone, which were shown to be dependent upon the dosage of FA injected. The fluorescence spectra, UV spectra and gel permeation chromatography of the alkaline extracts of the bone showed similar characteristics to FA. In in-vivo rat tests and in-vitro experiments of cultured chicken cartilage tissue with tritium labeled FA, the results showed that 3H-FA could be incorporated into the bone and cartilage of rats.

Animals↗
PubMed1996

ATPase activity of the cystic fibrosis transmembrane conductance regulator.

The gene mutated in cystic fibrosis codes for the cystic fibrosis transmembrane conductance regulator (CFTR), a cyclic AMP-activated chloride channel thought to be critical for salt and water transport by epithelial cells. Plausible models exist to describe a role for ATP hydrolysis in CFTR channel activity; however, biochemical evidence that CFTR possesses intrinsic ATPase activity is lacking. In this study, we report the first measurements of the rate of ATP hydrolysis by purified, reconstituted CFTR. The mutation CFTRG551D resides within a motif conserved in many nucleotidases and is known to cause severe human disease. Following reconstitution the mutant protein exhibited both defective ATP hydrolysis and channel gating, providing direct evidence that CFTR utilizes ATP to gate its channel activity.

Adenosine Triphosphatases↗
PubMed1996

Mucosal polyamine measurements and colorectal cancer risk.

Polyamines are short-chain aliphatic amines required for normal cellular growth that are ubiquitously found in all living tissues. Polyamine content has been shown to correlate with cellular proliferation. Quantitation of polyamines may thus provide a biochemical measure of proliferation in the colorectal mucosa where dysregulated epithelial proliferation is associated with colorectal cancer risk. A case-control study was conducted to validate the hypothesized association between mucosal polyamine measurements and colorectal cancer risk. Polyamines were measured in 4-6 multiple rectal mucosal biopsies from 11 normal control subjects and seven case patients with colon cancer. Compared with the controls, mean polyamine measurements, after adjustment for age and sex, were significantly increased for spermidine (P < 0.003) and spermine (P < 0.017). Subsequent analysis indicated that in controls 1-4 biopsies appeared adequate to characterize an individual. However, mucosal polyamines in the cases exhibited more sampling variability, requiring 4-8 biopsies to achieve an acceptable level of reliability. After adjustment for age and sex, the odds ratios for spermidine and spermine levels, compared to the controls, were 4.8 (95% confidence interval: 1.6-33.7) and 2.3 (1.2-6.3), respectively. The results of this study indicate that increases of mucosal polyamine measurements, after taking the sampling and methodological variability into account, are significantly associated with colorectal cancer risk, and suggest that polyamine measurements in rectal mucosa may play an important role as biomarkers for identifying high-risk individuals and/or for using as intermediate endpoints in prevention trials.

Aged↗