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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 649 records · Page 36Linked to original sources
PubMed1998

Microencapsulation of rat islets prolongs xenograft survival in diabetic mice.

OBJECTIVE: To protect the transplanted islets from the host's immune system by means of immunoexclusion membranes. METHODS: Rat islets were isolated from Wistar rat pancreas by ductal collagenase distention, stationary digestion, and finally with the aid of dextran gradient separation. Then the islets were encapsulated in alginate-polylysine-alginate (APA) semipermeable membranes. RESULTS: In vitro studies demonstrated that encapsulated islets secreted insulin in response to glucose challenge for at least 8 weeks, which was similar to free islets. In vivo studies showed that 15 streptozotocin (STZ)-induced diabetic mice were transplanted intraperitoneally with 1000 encapsulated islets without immunosuppression. Diabetes was reversed within 3 days, and the mice remained normoglycemic for up to 160 days, with a mean xenograft survival time of 126 days. The encapsulated islets had a significantly greater effect than unencapsulated islets, which functioned for less than 8 days. CONCLUSIONS: Encapsulation of pancreatic islets in semipermeable membranes can effectively prolong xenograft survival without immunosuppression in an animal model.

Animals↗
PubMed1998

Isolation and identification of xylitol dehydrogenase gene from Trichoderma reesei.

A cDNA sub-library from the fungus Trichoderma reesei grown on xylan was constructed in S.cerevisiae recombinant strain H475 harboring a xylose reductase (XR) gene from Pichia stipitis. The xylitol dehydrogenase (XDH) gene was screened from sub-library on a SC selective medium in which xylose was used as a sole carbon source. The length of XDH gene, xdh1, was about 1.3 kb. Southern, Northern and Western blots were carried out, indicating that xdh1 has high affinity with T.reesei and the molecular weight of the xylitol dehydrogenase from T.reesei was about 40 kDa. The strain HX1 harboring both the XR gene from P.stipitis and the XDH gene from T.reesei was able to grow on the xylose medium and converted more than 90% of the xylose into xylitol, ethanol, and other by-products.

Cloning, Molecular↗
PubMed1998

Construction of a YAC contig encompassing G200 locus of rice via chromosome walking.

Map-based gene cloning is now widely used to isolate genes of unknown products. After fine mapping of a target gene is completed, the key step to head forward is to construct series of contigs covering the target gene through chromosome walking. To approach the final goal of cloning a wide compatible gene of rice (S5 locus), the flanking G200 marker was used as a starting point to walk. Four positive clones ranging from 240 approximately 650 kb were obtained from the rice genomic YAC library (RGP, Japan). With the ends of YAC inserts isolated by inverse-PCR, a YAC contig of 3 cM was initially built. Next, chromosome walking was performed with the two distal ends of the contig and another seven positive YAC clones were screened out, leading to the contig extending to about 8 cM.

Chromosome Walking↗
PubMed1998

An experimental study on rhBMP-2 composite bone substitute for repairing craniomaxillary bone defects.

OBJECTIVE: To measure bone regenerative effects in animal calvarial or mandibular critical-size defects using recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with four selected carriers. MATERIALS AND METHODS: The composite bone grafts were obtained by combining rhBMP-2 with chitin, coral, coral-based porous HA (CHA), and xenogeneic cancellous bone, respectively. These materials were implanted on the calvarial or mandibular defect of rabbits and on the calvarial defect of rats. Each carrier material was also studied as a control group. The animals were examined 2, 4, 8, and 12 weeks after implantation by radiography, histology (under light microscope and scanning electron microscope), immunohistochemistry, and biomechanics. RESULTS: The results showed that the composite graft was absorbed gradually after it was implanted into the defect, during which time new bone was formed within the combined material in the defect site; the amount of new bone increased as time elapsed. At 12 weeks the composite was replaced completely by bone except in the CHA group. In contrast, a large amount of fibrous tissue, and little new bone, formed on the area of the bone defect when the carrier material alone was implanted. CONCLUSIONS: All materials tested seem to be suitable carriers for rhBMP-2, which plays a very important role in new bone formation. These composite bone substitutes may be ideal materials for repairing various bone defects in the craniomaxillofacial region.

Animals↗
PubMed1998

An observation on the mimic ecology of the oncomelania hupensis in three-Gorge-reservoir areas.

According to the modulation of three-gorge-reservoir water level, the two observation spots were established at Gaoyang Town and Jianshe Village in Xingshan County of Hubei Province in order to observe the survival and reproduction of the oncomelania under different ecological conditions. Our one-year observation revealed that most settled oncomelania died between June and August in the year and only a few of them survived the winter. The oncomelania hupensis's survival rate in group I, II, III settled in Gaoyang Town was 10%, 1%, 0%, respectively, and the oncomelania Sichuan's 12.5%, 22.5%, 13.5%. The rates obtained from spots in Jianshe Village is 0%, 2%, 0% and 9.5%, 19%, 3%, respectively. The survival rate of oncomelania Sichuan was higher than that of the oncomelania hupensis in the two spots. After draining the feeding pools, the soil samples were harvested and used for egg-hatching. The numbers of eggs that hatched in group I, II in Gaoyang were 1 and 2, respectively. The young oncomelania were found in each spot pool after the drainage, suggesting that the local condition is favorable to the oncomelania and the mating season of each group oncomelania is from April to August with the most active mating time being from May to June.

Animals↗
PubMed1998

[Antisense oligodeoxynucleotide of TGF alpha inhibits its gene expression and proliferation of a human glioma cell line].

OBJECTIVE: To study the effect of antisense oligodeoxynucleotide(ON) of TGF alpha on its gene expression in TJ 905 cell line. METHODS: Antisense and sense TGF alpha phosphorothioate ON (SON) and random SON were synthesized and transfected to TJ 905 cells mediated by lipofectin. Their effects on the TGF alpha gene expression were examined by in situ hybridization of TGF alpha mRNA, immunohistochemical study and cell count. RESULTS: (1) TGF alpha antisense SON could significantly inhibit the growth of TJ 905 cell line. The inhibition peaked at 24 hour after transfection, the inhibition rate reached 68% at 20 microM, and the effect decreased 72 hours after transfection. The inhibition effect was dose dependent. (2) Antisense TGF alpha SON inhibited TGF alpha expressions at both mRNA and protein levels. CONCLUSION: Antisense TGF alpha SON can inhibit the expressions of TGF alpha and markedly inhibit cell growth of human glioma TJ 905 cell line. TGF alpha contributes in the growth potential of glioma.

Brain Neoplasms↗
PubMed1998

[Inhibition of apoptosis by bcr-abl fusion gene in K562 cells].

OBJECTIVE: To investigate the effect of bcr-abl fusion gene on CML cell apoptosis. METHODS: Apoptosis of in vitro cultured K562 cells was observed after exposure to synthetic 18-mer antisense oligodeoxynucleotide complementary to the bcr-abl junction (b3a2). RESULTS: Apoptosis of K562 cells was significantly increased associated with inhibition of bcr-abl expression. CONCLUSION: bcr-abl fusion gene formation due to chromosome translocation may be the major mechanism of CML via inhibition of apoptosis.

Apoptosis↗
PubMed1998

[The effects of diltiazem on pulmonary hemodynamics and oxygenation in copd induced pulmonary hypertension].

OBJECTIVE: To study hemodynamic the effects of intravenous diltiazem on COPD induced pulmonary hypertention. METHODS: 11 cases in exacerbation stage were chosen to study. Swan-Ganz catheterization were taken for hemodynamic monitoring. RESULTS: After the administration of diltiazem, pulmonary vascular resistance, pulmonary pressure, right artrial pressure and heart rate decreased significantly (the extents decreased were 14.0 kPa.s-1.L-1, 0.62-1.27 kPa, 0.27-0.40 kPa and 25-30 beats/min respectively, P < 0.05); Cardiac output and stroke volume increased identically (the extents increased were 0.3-0.6 L.min-1.m-2 and 5-9 ml.beat-1.m-2 respectively, P < 0.05); No significant changes found in Qs/Qt, PaO2 and systemic blood pressure. CONCLUSION: Our study showed that diltiazem produces beneficial pulmonary hemodynamic effects without oxygenation compromise in COPD cases and has a strong indication in those who complicated with superventricular tachycardia.

Aged↗
PubMed1998

A pathological study of in situ thrombosis of small pulmonary arteries and arterioles in autopsy cases of chronic cor pulmonale.

OBJECTIVE: To investigate the incidence of in situ thrombosis of small pulmonary arteries and arterioles during the exacerbation stage of chronic cor pulmonale. METHODS: 49 autopsy cases died from the exacerbation of chronic cor pulmonale were chosen as the study group, while 103 other autopsy cases without chronic cor pulmonale and disseminated intravascular coagulation (DIC) as control group. Morphologic and morphometric studies were taken on lung tissues and other organs with focus on the thrombi in small pulmonary arteries and arterioles. RESULTS: 44 cases of the study group had multiple thrombi in small pulmonary arteries and arterioles, the incidence is 89.8%, and in 9 of them, thrombi in proximal pulmonary arteries co-existed, the incidence is 18.4%. 80% of the thrombi existed in pulmonary arterioles. In the control group, only 3 cases had thrombi in small pulmonary arteries and arterioles, the incidence is 2.9%. All thrombi adhered to endangium, implying that they were in situ thrombi. No intravascular thrombosis was found in other organs. chi 2 test showed that the incidence of thrombosis and the number of thrombi in small pulmonary arteries and arterioles in cases with chronic cor pulmonale were significantly higher than those of the control group (P < 0.01). CONCLUSIONS: Multiple in situ thrombosis in small pulmonary arteries and arterioles is a prominent and common pathological change during the exacerbation stage of chronic cor pulmonale. The study suggests a new diagnostic and therapeutic concept and gives a morphological and theoretical basis for the clinical application of anticoagulants or even the thrombolytic agents for the cases of chronic cor pulmonale in the exacerbation stage.

Aged↗
PubMed1998

Polymorphism of the glycogen synthase gene and non-insulin-dependent diabetes mellitus in Chinese population.

OBJECTIVE: To investigate the possible association between the Xbal polymorphism of the glycogen synthase gene and non-insulin-dependent diabetes mellitus (NIDDM) in Chinese population. METHODS: 216 NIDDM patients and 106 healthy controls were studied. DNA fragment containing Xbal restriction site was amplified by the polymerase chain reaction, digested by the Xbal enzyme and compared by gel electrophoresis with a positive control from Finland. RESULTS: The Xbal polymorphism was found in 18 of 216 Chinese patients (8.3%) and was also found in 10 of 106 controls (9.4%) (P > 0.05). CONCLUSIONS: The results suggest that the Xbal polymorphism of the glycogen synthase gene could not be used as a genetic marker for NIDDM in Chinese population of Henan Han nationality.

Adult↗
PubMed1998

[In vivo inductive effect of hemin on the erythroid progenitor of the normal and aplastic anemia mice].

OBJECTIVE: To investigate the in vivo effect of hemin on erythroid progenitor of the normal and aplastic anemia mice. METHODS: BFU-E and CFU-E of normal and aplastic anemia(AA) mice were assayed at different time (6 h, 12 h and 24 h) after hemin injection on a dosage of 6.50 micrograms/g body weight, and at 6 h after injection of different doses of hemin (0.65 microgram/g, 6.50 micrograms/g and 13.00 micrograms/g body weight). RESULTS: The yields of BFU-E and CFU-E from AA mice were reduced compared with that from normal mice. At 6 h after hemin injection (6.50 micrograms/g b.w.), the yields of BFU-E and CFU-E from AA mice were increased from 3 +/- 2/femur and 12 +/- 3/femur to 10 +/- 2/femur (P < 0.01) and 39 +/- 12/femur (P < 0.01), respectively, and so did the case for normal mice (for BFU-E, from 1,056 +/- 160/femur to 3,410 +/- 708/femur, P < 0.01, and for CFU-E, from 12 +/- 3/five 200x fields to 38 +/- 3/five 200x fields, P < 0.01). Low dose of hemin had no inductive effect. CONCLUSION: Hemin is a in vivo inducer of erythroid progenitors both in normal and AA mice.

Anemia, Aplastic↗
PubMed1998

The influence of impaired microvasculature on regional blood flow of the spinal cord after microsurgery.

OBJECTIVE: To further investigate the impact of impaired microvasculature of spinal cord and its physiological compensation on postoperative morbidity after intramedullary microsurgery. METHODS: In 120 cats, the segmental anterior longitudinal spinal arteries (ALSA), the posterior longitudinal spinal arteries (PLSA), and the unilateral radiculomedullary arteries (RMA) were selectively coagulated in different patterns. Hydrogen electrode technique was used to detect the changes of regional blood flow of the spinal cord at different segments. Benzidine dihydrochloride (BDHC) staining was used to observe the microvascular pattern of the spinal cord, tetrazolium chloride (TTC) staining was applied to morphometric analysis of the ischemic area, and hematoxylin-eosin staining was applied to histologic examination. RESULTS: When the segmental ALSA was injured, the blood flow of the gray matter and white matter decreased greatly. Since the central arteries were the terminal blood supply arteries, no compensation occurred after the injury. The blood flow of the segment below the impaired segment hardly changed, indicating that the direction of the blood flow in ALSA altered to adapt the changes of the microvasculature. Injury to the unilateral PLSA and RMA at both cervical and lumbar area only caused a minor decrease in the regional blood flow, unless the perimedullary arterial system was considerably injured. In the thoracic medullary segment, the sparse microvasculature was the main cause for the segment vulnerable to ischemia and infarction. This was caused by not only the rarity of RMA as an anatomic factor, but also the small number and low activity of the neurons at this area. After microsurgery, the impairment and decompensation of the microvasculature were closely related to the ischemic volume of and pathological changes in the spinal cord. CONCLUSION: The impairment and decompensation of microvasculature after microsurgery are the rudimentary causes of spinal cord ischemia. During operation, one should protect the terminal arteries to decrease the severity of injury to the perimedullary system, and do the best to avoid disturbance of microvasculature to accelerate the recovery of postoperative ischemia and neurological dysfunction of the spinal cord.

Adaptation, Physiological↗
PubMed1998

[The correlative study on nitric oxide and cotinine nicotine metabolite in smokers' urine].

OBJECTIVE: In order to observe the changes of nitric oxide (NO) affected by smoking and their relationship in vivo. METHOD: 60 male nonsmoker as the control group, 192 male smoked as the study group which was divided into 4 subgroups (1-10, 11-20, 21-30 and > 30) according to the number of cigarettes smoked per day. The metabolite of nicotine-cotinine in urine was assayed by means of barbituric acid. Cotinine was used as an objective indicator to reflect the smoking quantity. The urinary NO (NO2.-) was determined with colorimetric estimation. RESULT: The urinary cotinine level in the 4 subgroups were 6.6 +/- 1.6, 25.1 +/- 6.2, 37.8 +/- 8.5, 53.6 +/- 8.3 (mumol/L) respectively. The urinary NO of nonsmokers were 4.43 +/- 0.97 (mumol/L), in the 4 subgroups it was 3.04 +/- 0.07, 2.75 +/- 0.05, 2.18 +/- 0.01, 1.60 +/- 0.01 (mumol/L) respectively. The results of statistical analysis between the 4 subgroups were t = 4.2894, P < 0.01; t = 2.7446, P < 0.01; t = 2.7667, P < 0.01 accordingly. As compared between the 4 subgroups of smokers and the nonsmokers, the statistical results were t = 2.7118, P < 0.01; t = 3.1826, P < 0.01; t = 3.2100, P < 0.01; t = 4.6600, P < 0.01; respectively. The statistical differences between the 4 subgroups were t = 2.9286, P < 0.01; t = 3.0357, P < 0.01; t = 3.8181, P < 0.01; t = 2.2160, P < 0.05 respectively. There was a good positive correlation between the number of cigarette smoked and urinary cotinine content (r = 0.8626, P < 0.01), also a significant negative correlation between it and urinary NO level (r = -0.6596, P < 0.05). A negative correlation could be observed between urinary cotinine and NO (r = -0.6026, P < 0.05). CONCLUSION: With the increase of quantity and duration of smoking, the NO content in vivo will decrease, suggested that the vascular endothelial cells could be damaged severely.

Adult↗
PubMed1998

[Simultaneous determination of creatinine, pseudouridine and uric acid in serum and urine by high performance liquid chromatography].

In this paper a sensitive, rapid and simple HPLC method for the simultaneous determination of creatinine (Cr), pseudouridine (Pu) and uric acid(UA) has been established. We have evaluated clinical value of the method in the early diagnosis of diabetic nephropathy (DN). Separation was obtained using Shim-pack CLC-ODS 15 x 0.6 cm column and mobile phase of buffer solution of phosphate (pH 3.0, 0.02 mol/L) with flow rate of 1 mL/min. Detection was performed with UV detector at an automatic adjustment of wavelength. The recoveries of Cr, Pu and UA were 101.4%, 104.9% and 105.0% respectively. The calibration curves were linear within the concentration range of 8.6-274.6 mumol/L for Cr, 0.72-22.93 mumol/L for Pu and 19.1-612.7 mumol/L for UA (n = 6, r > 0.999, p < 0.01). The CV for within day and between day measurements were < 2.5% and < 5.0% respectively. In addition, Pu, Cr and UA were simultaneously determined in serum and urine of 39 patients with diabetic mellitus (DM). 15 patients with nephrotic syndrome (NS) and 53 normal subjects by the method. Results include: 1. the levels of serum Pu in all DM patients (100%) with microalbuminuria (MiAU) and macroalbuminuria (MaAU) were greater than maximum of normal subjects (X + 2S). In addition, in 9 DM patients (41%) with normal albuminuria (NAU) the levels were also greater than the maximum. 2. In patients with DM, there was no correlation between the serum Pu and the urinary albumin excretion (UAE), whereas the serum Pu correlated closely with the serum Cr. However, the incidence for serum Pu increase was significantly greater in patients. 3. The levels of serum Pu in patients with NS were greater than those in control subjects and patients with DM. Conclusion is that the determination of serum Pu could be used as sensitivity index for the early diagnosis of DN.

Chromatography, High Pressure Liquid↗
PubMed1998

[Separation and determination of naproxen by reversed-phase high performance liquid chromatography].

A reversed-phase HPLC method has been developed for the separation and determination of naproxen and its bromo-substituted compound. These compounds were separated on a Shim-pack CLC ODS column (5 microns, 250 mm x 4.6 mm i.d.) by using a methanol-water (80/20, V/V) solution containing 50 mmol/L lactic acid and adjusted to pH 2.5 with perchloric acid as mobile phase, with flow rate of 0.8 mL/min and UV detection at 271 nm. Benzoic acid was selected as an internal standard. At the concentration range of 5-100 mg/L, the linear internal standard working curves with r > 0.9995 were obtained. The accuracy of this method for naproxen and its bromo-substituted compound were 99.83%-102.07% and 99.00%-100.83%, and RSD were < 2.58% and < 3.64% respectively.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

[Isolation and purification of the active principle from agkistrodon acutus snake venom by high performance ion-exchange liquid chromatography].

The active component from Agkistrodon acutus snake venom was further purified by high performance ion-exchange liquid chromatography over a Protein-PAK DEAE-8HR column(10.0 mm i.d. x 100 mm). The elution was operated with a linear gradient from 10% to 100% NaCl-0.02 mol/L Tris-HCl buffer(pH 8.0). The quantitative results were calculated as 45.41% based on peak area nomalization and the purity of the active component was 90% determined by electrophoresis.

Agkistrodon↗