Search PubMed⌕ Search

Biomedical subjects

H Wang

Publications and source records attributed to H Wang.

At least 883 records · Page 49Linked to original sources
PubMed2000

[The construction and physical-mechanical characterization of polymer foams of D. L-PLA].

This study was intended to construct biogradable polymer foam used in tissue engineering. The D. L-PLA was supplied by chengdu institute of organic chemistry. Biogradable polymer membranes were prepared with a novel solvent-casting particulate-leaching technique, then, the constituent membranes with the proper order were laminated to produce three-dimensional foams with continuous pore structure and morphology. Afterwards, the physical-mechanical property of polymer foams were tested. The test results indicated that the lamination process did not change the physical-mechanical property of the polymer membranes.

Biocompatible Materials↗
PubMed2000

[Different flow augmentations in coronary, carotid and renal arteries with ECP in experimental canines].

Different flow augmentations were found in canine's coronary, carotid and renal arteries with ECP because of their different anatomical locations in aorta. We used the Electromagnetic Blood Flowmeters to measure the blood flow pre-ECP and during ECP. The results showed ECP increased the diastolic flow of coronary, carotid and renal arteries by 24.48% +/- 1.29%, 27.18% +/- 0.94% and 20.68% +/- 0.80% respectively, decreased their systolic flow by 4.77% +/- 0.48%, 6.45% +/- 0.99% and 9.60% +/- 0.70%, but augmented their mean flow by 18.24% +/- 2.01%, 19.38% +/- 1.47% and 8.42% +/- 0.94% respectively in experimental dogs. These data demonstrate that ECP can greatly increase the mean flow of coronary and carotid arteries but at the same time patently decrease the systolic flow of renal artery.

Animals↗
PubMed2000

Multiple skeletal muscle mitochondrial DNA deletions in patients with unilateral peripheral arterial disease.

Peripheral arterial disease (PAD) is associated with metabolic derangements and accumulation of the common 4977 bp mitochondrial DNA (mtDNA) deletion mutation. The current study was undertaken to test the hypothesis that PAD is associated with multiple mtDNA deletions. Gastrocnemius biopsies were obtained from nine patients with unilateral PAD. DNA extracted from the biopsies was analyzed for mtDNA deletions using a primer-shift PCR strategy. Multiple primers and strict, prospective criteria were used to identify deletions. PAD was associated with multiple mtDNA deletions (average of 8.2 distinct deletions in muscle from the hemodynamically affected limb). mtDNA injury was present in both the worse- and less-affected limbs of the unilateral PAD patients, and the estimated degree of mtDNA injury was strongly correlated in the two limbs on an intra-subject basis. The 4977 bp deletion was frequently identified, but was not always the deletion of highest frequency in individual samples. The estimated relative frequency of the 4977 bp deletion was correlated with the overall mtDNA injury in the biopsies. In summary, PAD is associated with mtDNA injury as reflected by multiple deletion mutations. As the mutations are not limited to the ischemic limb in unilateral patients, they are unlikely to contribute to the pathophysiology of claudication.

Aged↗
PubMed2000

Isolation and characterization of rat gastric microvascular endothelial cells as a model for studying gastric angiogenesis in vitro.

We have previously characterized morphologic features of wounding-induced angiogenesis that occurs in response to acute and chronic gastric mucosal injury. As a means of investigating the molecular mechanisms underlying gastric angiogenesis, microvascular endothelial cells were isolated from stomachs of normal (non-injured) rats. The isolation procedure adapted and combined aspects of previous methods and employed positive selection using magnetic beads coated with monoclonal antibody specific for rat CD31 (PECAM-1), a cell surface marker restricted to platelets, monocytes, T lymphocytes and endothelial cells. The isolated microvascular endothelial cells expressed vascular endothelium-specific antigen and the endothelial-specific receptors, Tie2 and flt-1 (VEGFR1). When plated on growth factor-reduced matrigel, the isolated microvascular endothelial cells formed capillary-like structures reflecting in vitro angiogenesis. These cells were also responsive to vascular endothelial growth factor, VEGF, further verifying their endothelial nature. The rat microvascular endothelial cells isolated by this procedure should be useful in delineating molecular mechanisms and regulation of the angiogenesis that is essential for the healing of acute and chronic gastric injury.

Animals↗
PubMed2000

[Experimental study on an animal model of axonal form Guillain-Barre syndrome].

OBJECTIVE: To investigate an animal model of axonal form Guillain-Barre syndrome (GBS). METHODS: A strain of Campylobacter jejuni (Cj PENO: 19) from stools of a patient with axonal form GBS was isolated. After the lypopolysaccharides (LPS) were extracted from the strain, they were inoculated into 26 rabbits, 10 micrograms per week. RESULTS: Three rabbits showed paralysis, with an incidence rate of 11.54%. For the three rabbits, LPS was inoculated two, three and three times, respectively. Pathological examination showed serious axonal degeneration in the sciatic nerve. The electrophysiological features showed motor axon damage. CONCLUSION: The results suggested the presence of an axonal form GBS. LPS in Cj could play an important role in causing axonal form GBS.

Animals↗
PubMed2000

[Study on human sensitivity of extremely low frequency electromagnetic field].

In this paper, the action potential through membrane is calculated and analyzed based on the crowd model. The analysis shows that membrane action potential will be amplified if the coefficient k1, k2 meet some certain conditions. This effect could cause ionic current increase and even results in electroporation, membrane broken. The result can be used to explain some athermal bioeffect of living beings in weak EMF and is helpful for biomedicine application.

Cell Membrane↗
PubMed2000

Improvement of transdermal permeation of captopril by iontophoresis.

AIM: The feasibility of iontophoresis on the transdermal delivery of captopril was studied. METHODS: Iontophoresis was employed for enhancing transdermal transport of captopril through rat skin in vitro and in vivo. RESULTS: It was demonstrated that the iontophoresis-induced flux of captopril was affected by various factors such as pH, ionic concentration, and the concentration of captopril in donor compartments as well as the applied electric current intensity. Electric current could induce several-fold increase in captopril flux with hydrogel. Skin permeation study in vivo in rats demonstrated that iontophoresis could effectively promote the transdermal transport of captopril without significant skin irritation. Captopril concentration in plasma reached plateau (approximately 0.9 microgram/mL) at 1 h after current application and was maintained at the same level during the experiment. On the contrary, captopril could not be detected in plasma when the current was not applied. No obvious skin irritation was observed after 9-h continuous iontophoresis. CONCLUSION: Transdermal delivery of captopril can be effectively improved by iontopophoresis.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

[Human proximal tubular epithelial cells activated by low density lipoprotein promote phenotypic changes in renal interstitial fibroblasts].

OBJECTIVE: To study the effects of low density lipoprotein (LDL) on human proximal tubular epithelial cells (HK-2), and further examine the effects of HK-2 activated by LDL on phenotypic changes in human renal interstitial fibroblasts (RIFB). METHODS: 3H-thymidine incorporation and direct cell counting were performed to detect cell proliferation. Message RNA and protein of alpha-smooth muscle-actin (alpha-SM-actin) were analyzed by Northern and Western blot. Fibronectin or laminin levels were determined using an inhibition enzyme linked immunosorbant assay. After exposed to LDL-activated HK-2 conditioned media (CM), total collagen synthesis or collagen III mRNA expression was measured by proline incorporation or RT-PCR in primary cultures of RIFB. RESULTS: Incubation of HK-2 with LDL (100-500 micrograms/ml) for 72 hours stimulated HK-2 proliferation. mRNA expression, protein synthesis of alpha-SM-actin and secretory fibronectin level were up-regulated by LDL at a concentration of 250 micrograms/ml. When exposed to CM from LDL-treated HK-2, thymidine incorporation rate was not changed in RIFB, but alpha-SM-actin production was significantly enhanced. CM from LDL-treated HK-2 also showed the stimulated proline incorporation and secretion of fibronectin or laminin. Expression collegen III mRNA was up-regulated by CM from LDL-treated HK-2 cells. CONCLUSION: The results indicate that LDL stimulates HK-2 cells proliferation, phenotypic changes and fibronectin synthesis. Human proximal tubular epithelial cells activated by LDL modulate the phenotype and matrix production in RIFB.

Cell Division↗
PubMed2000

[Isolation of genes associated with renoprotective effects of astragalus and angelica by silver staining mRNA differential display].

OBJECTIVE: To isolate genes associated with chronic progression of renal diseases and renoprotective effects of Astragalus and Angelica(A & A). METHODS: Chronic puromycin nephropathy, which is characterized by massive proteinuria and progressive glomerular sclerosis and tubulointerstitial fibrosis, was induced in SD rats by repeated peritoneal injections of puromycin. Rats were randomly divided into three groups: (1) normal control (n = 7), (2) puromycin nephropathy without A&A treatment (n = 7), (3) puromycin nephropathy A & A treatment (3 ml/d, n = 7). After 12 weeks, serum, urine and renal tissue were collected for study. The technique of silver staining mRNA differential display (DD) was used to investigate the changes of gene expression in kidneys of normal and nephropathy with and without A&A treatment rats. Genes expressing differently during the progression of renal diseases were isolated and the progression could be normalized by A&A. RESULTS: Twenty-six candidate cDNA fragments were isolated with DD. Northern blot analysis of eight randomly chosen candidate cDNA fragments demonstrated one exhibiting reduced mRNA expression in the fibrogenic process but upregulated by A&A treatment. Besides kidney, the gene was also expressed in lung, heart, liver and spleen. Whether it takes part in fibrogenic processes of these organs needs further study. Homology analysis through BLAST revealed that this gene was a novel one. CONCLUSION: Silver staining mRNA differential display is a simple and quick technique for isolating differently expressed genes. The downregulated expression of the isolated new gene may contribute significantly to the fibrogenic process and be associated with A&A's protective effects.

Angelica sinensis↗
PubMed2000

[The investigation of glucocorticoid receptor in peripheral blood mononuclear cells from patients with myasthenia gravis].

OBJECTIVE: To investigate the alteration of glucocorticoid receptor(GR) in peripheral blood mononuclear cells (PBMC) from patients with myasthenia gravis(MG) and to explore its mechanism. METHODS: 3H-dexamethansone binding assay and Scatchard analysis were used to measure the number of GR and dissociation constant in PBMC from 193 MG patients, 10 patients with other neuroimmunological disorders, 66 with cerebral vascular disorders (CVD) and 35 healthy donors. Slot blot hybridization was used to detect GRmRNA. RESULTS: GR numbers in MG patients were much lower than those in healthy controls (P < 0.01), but GR affinity between these two groups was not remarkably different (P > 0.05). GR numbers of PBMC from MG patients after culture in normal plasma were not significantly different from those before culture. No obvious change was observed in GR numbers of PBMC from healthy donors after the cells were incubated with MG plasma. GRmRNA of PBMC in MG patients was significantly lower than that in healthy donors, and was well correlated with GR numbers (r = 0.89, P < 0.01). CONCLUSION: GR numbers are low in MG patients. The decrease of GR numbers may be related to the decrease of GRmRNA transcription.

Adolescent↗
PubMed2000

Thoracic epidural analgesia with morphine does not prevent postthoracotomy pain syndrome: a survey of 159 patients.

BACKGROUND: This retrospective study sought to determine the incidence of postthoracotomy pain syndrome (PTPS), and whether epidural morphine for the postoperative analgesia could prevent the development of PTPS. METHODS: We reviewed the charts of 372 patients who had undergone thoracotomy. The majority underwent general anesthesia (GA) combined with thoracic epidural analgesia (TEA). Of the 372 patients, only 159 (42%) were available for interview. Patients were divided into two groups based on the duration of pain, i.e., pain group (pain > 3 months, n = 65) and pain-free group (pain < 3 months, n = 94). RESULTS: Both groups were comparable regarding sex, age, weight, height, smoking, alcohol ingestion, education, marital status, duration of surgery, and the number of patients either receiving GA plus TEA or GA alone. About 41% of the patients experienced PTPS that persisted for 21 +/- 12 mon (follow-up: 28 +/- 12 mon). Most pain was mild or moderate and was usually described as being only a discomfort. Only 6.2% suffered severe pain with shooting, aching, burning or numbness. Patients with PTPS suffered more depression and insomnia. The incidence of PTPS was not different in patients who received GA alone or GA plus TEA (39% vs. 42%). CONCLUSIONS: Epidural morphine for postoperative analgesia that continued for 3 days appeared to have no effect in the prevention of PTPS.

Adult↗
PubMed2000

[Discovery of a new subtype of SEO virus].

OBJECTIVE: The M and S segments of Cou3, a Hantavirus strain isolated from Rattus norvegieus were partially reverse transcripted, PCR amplified and sequenced with ABI 373 DNA sequencer to observe the differences from other SEO type viruses. METHODS: RT-PCR was used to amplify M and S segments of Cou3 strain, and then the nucleotide (nt) sequences of the segments were analysed. Phylogenetic tree analysis was also performed. RESULTS: The different property through PCR amplification and partial nucleotide sequence data showed that Gou3 was a Hantavirus of SEO type with significance difference from the other SEO type viruses. The nt sequence homology between Cou3 and the other SEO type viruses was only about 85%, but the deduced amino acid (aa) sequence of partial glycoprotein was highly conservative, at least as same as that among the other SEO type viruses. Sequence analysis also showed that nt or aa sequence homology between Gou3, or other SEO type, and HTN type viruses was nearly the same, while the phylogenetic tree analysis showed that Gou3 was a virus which was between HTN and the other SEO type viruses but closer to the latter. CONCLUSIONS: Gou3 is a SEO virus but belongs to a new subtype.

Amino Acid Sequence↗
PubMed2000

[Establishment of a Hantaan virus infected mouse neuron cell model].

OBJECTIVE: To establish a neuron cells model for Hantaan virus (HTNV) infection by using the cultures of cortical neurons of mouse embryo. Changes and mechanism of the damage in neurons after HTNV infection were studied. METHODS: The cortical neurons of 16-19 day old mouse embryo were cultured and infected with HTNV (A9 strain). Indirect immunofluorescence test (IFT), MTT colorimetric analysis and immunohistochemistry assay (IHCA) were used to detect immunofluorescent antibody reaction of neurons, growth and development of the neurons. RESULTS: In neurons of HTNV infected mouse embryo, continually cultured for one week, lFT antigen was detected positive, the activity of the infected neurons was reduced obviously and the growth of neurons was obstructed. CONCLUSIONS: Direct infection of HTNV on the cultured neurons was identified, indicating that mouse embryonic critical neurons is one of the sensitive target cells for HTNV infection.

Animals↗
PubMed2000

Alterations of amino acid levels from striatum, hippocampus, and cerebral cortex induced by global cerebral ischemia in gerbil.

AIM: To investigate global cerebral ischemia-induced alterations in the levels of glutamate, aspartate, gamma-aminobutyric acid (GABA), glutamine, glycine, and taurine from hippocampus, striatum, and cerebral cortex in gerbils. METHODS: The gerbil global cerebral ischemia model was prepared by bilateral carotid artery occlusion; the contents of amino acids were assayed using high performance liquid chromatography (HPLC) combined with fluorescent detection after precolumn derivatization. RESULTS: After the ligation of bilateral carotid artery for 5 min and reperfusion for 60 min, the contents of glutamate from hippocampus, striatum, and cortex in gerbils were increased by 40%, 49%, and 67%, respectively. Similarly, the global cerebral ischemia resulted in increase by 80%, 69%, and 83% of aspartate contents in hippocampus, striatum, and cortex, respectively. Moreover, the same treatment also induced significant increases in the contents of GABA, glutamine, glycine, and taurine from various brain regions in gerbils. Furthermore, pretreatment with ketamine (120 mg/kg, i.p.) reversed ischemia-evoked increases of glutamate, aspartate, glycine, and glutamine in hippocampus, striatum, and cortex of gerbils. However, administration of ketamine (120 mg/kg, i.p.) markedly suppressed but not abolished the ischemia-induced increases of taurine and GABA from hippocampus, striatum, and cortex in gerbils. CONCLUSION: The increases of glutamate, aspartate, glycine, and glutamine induced by acute global cerebral ischemia may constitute the biochemical basis of ischemic brain damage. Correspondingly, the release of GABA and taurine may be an important self-protective mechanism. Ketamine may protect neurons against ischemic insult by inhibiting global cerebral ischemia-evoked increase of glutamate, glycine, and aspartate.

Animals↗
PubMed2000

[Isolation, identification and certain characteristics of a Hantaan virus proposed as candidate virus for killed vaccine].

OBJECTIVE: Isolation and identification of a Hantaan virus from HFRS patient's serum for killed vaccine development. METHODS: This virus temporally called FT14 detected by IFAT, RT-PCR. Partial sequence of M segment was determined by Sanger' a dideoxy chain termination method. RESULTS: The antigenicity and PCR amplification of the newly isolated virus FT14 proved that it belongs to virus of HTN type. Antiserum to the virus can neutralize many strains of Hantaan virus from different areas. The partial sequence of M segment of FT14, as compared with other HTN strains, showed great differences among nucleotide sequences, while the deduced amino acid sequence is comparatively conservative. The titer of the virus reached its peak at 9 days post inoculation in vitro, then the peak titer could last for a long time. CONCLUSIONS: This virus strain FT14 would be a good candidate virus for killed vaccine development.

Amino Acid Sequence↗
PubMed2000

[Detection of TT virus DNA by polymerase chain reaction-microplate hybridization].

OBJECTIVE: To establish a method for the detection of TT virus (TTV) DNA by polymerase chain reaction (PCR)-microplate hybridization and to find out various influential factors of the assay. METHODS: TTV DNA extracted by guanidinium thiocyanate was amplified by PCR, the PCR primers were pre-labeled with biotin. By conjugation of biotin with streptavidin, the amplified products were coated to the microplate well, and hybridized with FITC- probe simultaneously. After being reacted with Anti-Fluorescein POD, the products that contained FITC probe were coloured by TMB-H2O2 and then measured the optical density using a microplate reader at 450 nm wavelength. RESULTS: The optimal concentration of NaOH was 0.3 mol/L, and the optimal time of hybridization and enzymatic reaction was 60 minutes and 45 minutes, respectively. The results also showed that the positive rate of TTV infection in normal population, hepatitis A-G and hepatitis non A-G was 13.6%, 20.3% and 28.1%, respectively. CONCLUSIONS: Comparing the PCR-microplate hybridization with the electrophoresis assay, the former is simple, rapid, sensitive and specific and is expected to be a new technique instead of electrophoresis assay as a routine method for TTV DNA detection.

DNA Virus Infections↗