Biomedical subjects

Yan Wang

Publications and source records attributed to Yan Wang.

At least 487 records · Page 27Linked to original sources

PubMed2003

Hypoglycemic activity of ginseng glycopeptide.

AIM: To study the hypoglycemic activity of ginseng glycopeptide (GGP). METHODS: Normal mice or rabbits and alloxan or streptozotocin-induced hyperglycemic rats or mice were used in the study. Blood glucose and liver glycogen levels of the experimental animals during the trial period were analyzed by spectrophotometry with O-toluidine and iodine reagents, respectively. RESULTS: Significant decreases in blood glucose and liver glycogen levels were induced in a dose-dependent manner after administration of GGP 50, 100, or 200 mg/kg injected ip or sc to normal mice and injected im 30 or 60 mg/kg to normal rabbits. The hypoglycemic activity of GGP lasted for about 16 h, and were examined in both normal animals and hyperglycemic animals. CONCLUSION: GGP injection induced the pronounced decreases in blood glucose and liver glycogen levels in both normal and hyperglycemic animals.

Alloxan↗

PubMed2003

Hypoglycemic mechanism of ginseng glycopeptide.

AIM: To study the hypoglycemic mechanism of ginseng glycopeptide (GGP). METHODS: After administration of GGP, the levels of insulin, lactate dehydrogenase (LDH), lactic acid (LC), and oxygen consumption, as well as blood glucose (BG) and liver glycogen (LG) were measured. Based on these measurement results, the effects of GGP on insulin secretion and anaerobic/aerobic glycolysis were evaluated. Adenylate cyclase (AC) activity and cAMP level were measured to study the effects of GGP on BG and LG metabolism and to determine whether the effects were through second transmitting message system. Propranolol (beta-receptor antagonist) and phentolamine (alpha-receptor antagonist) were used to investigate whether hypoglycemic activity of GGP was through beta- or alpha-adrenoceptor. [3H]DHA (antagonist of beta-adrenoceptor) was used to determine GGP binding affinity to beta-adrenoceptor. Citrate synthetase (CTS), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and cytochrome oxidase (CCO) activities were measured to explore GGP effects on aerobic glycolysis in liver mitochondria. Phosphorylase (PP) activity was measured to study GGP effects on liver glycogen metabolism. RESULTS: cAMP content and AC activity were increased when BG and LG contents in liver of mice decreased. The decrease in liver glycogen induced by GGP was inhibited by pretreatment with propranolol. Radioligand receptor assay showed that GGP was competing in vitro with [3H]DHA to bind to beta-adrenoceptor of duck erythrocyte membrane, and IC50 of GGP was 63 nmol/L. GGP inhibited LDH activity at an appropriate dosage, at which contents of BG and LG could be effectively lowered. GGP also stimulated activities of SDH, MDH, CCO, CTS, and PP. CONCLUSION: The hypoglycemic activity of GGP may be attributed to the enhancement of aerobic glycolysis through stimulation of beta-adrenoceptor and increase of various rate-limiting enzyme activities related to tricarboxylic acid cycle.

Adrenergic beta-Agonists↗

PubMed2003

[Preparation of famotidine microemulsion and its quality evaluation].

OBJECTIVE: To study the preparation of famotidine microemulsion (FM) and its quality evaluation, thereby to establish the quality-control criteria for this preparation. METHODS: The formulations of the FM were optimized by studying the pseudoternary phase diagrams and its absorption in rat jejunum using in situ perfusion method. The morphology, particle size distribution, famotidine concentration and stability of the FM were studied. RESULTS: The optimization of formulation was completed successfully. Electron microscopy presented the FM as small spherical drops, with a mean diameter of 65 nm. The average recovery as determined by high-performance liquid chromatography was 97.63%, its mean RSD being 0.72%. CONCLUSION: The FM is easy to prepare with consistent quality, whose reliable determination method may be easily reproduced.

Animals↗

PubMed2003

[A cohort study on cerebral vascular hemodynamics accumulative score and risks of stroke].

OBJECTIVE: To estimate relative risk (RR) of cerebral vascular hemodynamics indexes (CVHI) accumulative score as well as some other risk factors of stroke. METHODS: A cohort study was carried out in 25 355 participants aged 35 and over in Northeast of China from 1994 to 2001. In the baseline survey, exposure rates of hypertension, diabetes, family history of stroke and hypertension, etc. were collected and CVHI was examined. CVHI accumulative score was synthesized according to contribution of single index. During the 7-year following up, 228 stroke cases were identified and stroke coming on was defined as the endpoint of observation. Uni-variable and multiple variables analysis were carried out for estimating RR of CVHI and other risk factors of stroke. RESULTS: Uni-variables analysis indicated that RR (95% confidence interval, CI) of Hypertension, heart diseases, diabetes, family history of hypertension and stroke, overweight or obesity, alcohol intake, cigarette smoking and CVHI < 75 scores were 3.23 (2.48 - 4.20), 2.53 (1.92 - 3.33), 2.38 (1.55 - 3.64), 1.32 (1.02 - 1.72), 1.82 (1.37 - 2.41), 1.62 (1.25 - 2.11), 1.48 (1.07 - 2.04), 1.76 (1.34 - 2.31) and 7.30 (5.43 - 9.80) respectively. Cox regression analysis showed that CVHI below 75 points, family history of stroke, cigarette smoking, heart disease, hypertension, age and sex were the factors being selected in equation. There was a significant dosage response between the decrease of CVHI score and the increase of stroke risk. RR of stroke reached 12.55 when CVHI below 75 points and history of hypertension appeared in the same individuals. CONCLUSION: Abnormality of CVHI score seemed to be the most important and independent factor among stroke risk factors. Decrease of CVHI score might serve as a marker of high risk and play important role in stroke, especially coexistence with hypertension.

Adult↗

PubMed2003

[Changes of cerebral vascular hemodynamics from normal population to stroke].

OBJECTIVE: To probe into changes of cerebral vascular hemodynamics indexes (CVHI) from normal population to different clinical stage before and after occurring of stroke. METHODS: Participants were selected from 25,355 stroke cohort study population aged 35 years and over in Northeast of China and 55 acute stroke patients were selected from Fuzhou PLA General Hospital. CVHI indexes were checked during baseline investigation or within one week after acute stroke. Participant enlisted in the study were divided into following 5 groups, normal population, high risk population, individuals before stroke, acute stroke patients and convalescence stroke patients. Characteristics of CVHI indexes in different population were analyzed and compared. RESULTS: V(min) of cerebral vascular in previous defined 5 group participants were 11.39 +/- 3.27, 9.66 +/- 3.18, 6.71 +/- 3.30, 4.13 +/- 1.27, 6.78 +/- 3.09, respectively. V(mean) and V(max) were with the same decreasing trends as V(min). However, RV in 5 group participants were 62.35 +/- 21.11, 82.32 +/- 31.16, 122.72 +/- 52.73, 137.46 +/- 49.56 and 115.89 +/- 55.51, respectively. Zcv, WV, DR and CP were also with the same increasing trends as RV. Abnormal rate of CVHI score (< 75 points) from normal population to convalescence stroke patients were 13.3%, 34.7%, 74.1%, 100% and 66.7%, respectively. CONCLUSION: From normal population to clinical stage of stroke, cerebral vascular velocity showed decreasing trends while other indexes, such as RV, Zcv, WV, DR and CP were increasing.

Brain↗

PubMed2003

[The reference range of cerebrovascular hemodynamics indexes parameters].

OBJECTIVE: To study the reference range of cerebrovascular hemodynamics indexes (CVHI) in a sampling population. METHODS: Fourteen thousand, four hundred and eighty participants without history of stroke or exposure to risk factors were screened from 26 cities in Northeast China, North China, East China, Northwest China, South China, and Southwest China in the prospective study on stroke intervention. CVHI were checked and 95% confidence intervals were calculated using normal distribution methods, which were grouped by age, sex, area, and check positions. RESULTS: Characteristics of CVHI 95% confidence intervals showed that low limit of carotid blood velocity as V(max), V(min), V(mean) decreased, but upper limit of cerebral RV, Zcv, WV, DR and CP increased with the increase of age. However, Q(mean) and DP did not show significant trends of age difference. Low limit of Q(mean), V(max) and upper limit of RV, DR, CP and DP in males were higher than that in females while upper limit of WV and Zcv in females were higher than that in males. Left carotid low limit of Q(mean), V(mean), V(max), V(min), and upper limit of WV, Zcv and CP were higher than that of the right but upper limit of RV, DR and DP were lower than that of the right. There were no obvious differences between areas. CONCLUSION: Obvious differences of CVHI 95% confidence intervals ranges were found between age groups, sex, and checking positions, respectively, suggesting that the reference ranges of CVHI to be estimated by every subgroup.

Adolescent↗

PubMed2003

[N2O concentration and its emission characteristics in Sanjiang plain wetland].

N2O concentration and its flux were measured in Sanjiang Plain wetland, from August to September in 2001, by using in situ closed chamber technique. The results showed that the mean N2O concentration above the ground was 281.7 x 10(-9) m3/m3, lower than the atmospheric N2O background, indicating the wetland maybe one of the important N2O sinks which scientists hadn't pay much attention to in the past. Four observation sites: Cares lasiocarpa, Alamagrostis angustifolia (I, II) and wheat land(had been harvested and in follow) were chosen according to water content and plant. The daily N2O emission models at four sites were different from each other, except site of wheat land emitted N2O persistently all day, the other sites emitted and absorbed alternately in one day. Temperature was the crucial factor for the diurnal variation. The mean N2O flux at four sites from August to September was 0.22 microgram/(m2.h), 1.75 microgram/(m2.h), 1.31 micrograms/(m2.h), 4.86 micrograms/(m2.h), respectively. Eh was the key factor for N2O emission characteristic in Sanjiang Plain wetland, and water content was another important factor.

China↗

PubMed2003

[Electrical charge and flocculation of composite flocculants made of polyaluminium].

A series of composite flocculants polyaluminium chloride (PAC)-polydimethydiallyammonium chloride (PDMDAAC) was prepared by using PAC with different basicity (B) and PDMDAAC was raw materials. The electrical charge of PAC-PDMDAAC was studied by electrophoretic mobility method. And the flocculating efficiency of PAC-PDMDAAC on treating water from Yellow River was also preliminarily examined by Jar-test. The experimental results show that the PAC-PDMDAAC is characterized by giving higher positive Zeta potential value and better flocculating effect than PAC. The B value of PAC and the content (P) of PDMDAAC in PAC-PDMDAAC had some effect on the Zeta potential and the turbidity-removal efficiency.

Aluminum Chloride↗

PubMed2003

[The study of distortion products otoacoustic emissions in pseudo-anacousia].

OBJECTIVE: To explore the technique that distinguish pseudo-anacousia. METHODS: 60 cases were divided into three groups (normal group, deafness sensorineura group and pretending hearing loss group). They all had been tested by distortion products otoacoustic emissions technique. RESULTS: (1) The DPOAE incidence of normal group is 94.00%. the DPOAE incidence of deafness sensorineura group is 22.00%. There were significant differences at statistics in DPOAE incidence (P < 0.01). those proved that patients (deafness sensorineura group) were in hearing problem. (2) The DPOAE incidence of pretending hearing loss group is 93.00%, there were no significant differences at statistics in DPOAE incidence between normal group and pretending hearing loss group (P > 0.01), furthermore when behavior threshold is over 50 dBHL, DPOAE incidence is no score. CONCLUSION: This study shows the technique can distinguish pretending hearing loss. The application of DPOAE can be used as a new tool in cases assessment of clinic forensic medicine.

Audiometry, Pure-Tone↗

PubMed2003

[Studies on the zinc bioavailability using stable isotope techniques].

Zinc is one of essential trace elements in humans. Zinc homeostasis is mainly regulated by the changes of intestinal absorption efficiency and endogenous excretion, namely the regulation of bioavailability. Studies on zinc bioavailability play an important role on a thorough understanding of zinc metabolism and reliable assessment on population zinc status. Stable isotopes are valuable tools for research on mineral bioavailability and metabolism. Zinc stable isotopes can be used for all population as tracers with no exposure to radiation. Since 1980s' many different stable isotope methods have been applied to the zinc metabolism research. However, limitations to these approaches and methodological problems remain to be resolved. In addition, the introduction and development of new analytical instruments not only make it possible to use zinc stable isotope, also greatly diminish the difficulty and cost on it. The paper is mainly focused on the zinc bioavailability and present a review of its development history, main research methods and analytical skills.

Biological Availability↗

PubMed2003

[Gene sequence analysis of SARS-associated coronavirus by nested RT-PCR].

OBJECTIVE: To explore an effective means for the detection of Severe Acute Respiratory Syndrome (SARS)- associated coronavirus. METHODS: The RNAs of the virus contained in the sputum samples from established SARS patients were extracted and reversely transcripted, followed by nested PCR using the reversely transcripted cDNA as the template. The PCR products were cloned then into the pMD18-T vectors, followed by sequence analysis. RESULTS: Specific fragments were amplified from the sputum samples of SARS patients, which were confirmed by DNA cloning and sequencing to belong to SARS-associated coronavirus. The Result of Blast shows only the difference in one nucleic acid from the TOR2 strain of SARS-associated coronavirus. CONCLUSION: Sequence analysis has confirmed the existence of SARS-associated coronavirus in the sputum samples of SARS patients, and nested RT-PCR is a quick, easy, and convenient way for the detection of the virus.

Base Sequence↗

PubMed2003

Mapping cortical areas associated with Chinese word processing using functional magnetic resonance imaging.

OBJECTIVES: To identify the cortical areas engaged during Chinese word processing using functional magnetic resonance imaging (fMRI) and to examine the reliability and reproducibility of fMRI for localization of functional areas in the human brain. METHODS: FMRI data were collected on 8 young, right-handed, native Chinese speakers during performance of Chinese synonym and homophone judgment tasks on two different clinical MRI systems (1.5 T GE Signa Horizon and 1.5 T Siemens Vision). A cross correlation analysis was used to statistically generate the activation map. RESULTS: Broca's area, Wernicke's area, bilateral extrastriate, and ventral temporal cortex were significantly activated during both the synonym and homophone activities. There was essentially no difference between results acquired on two different MRI systems. CONCLUSIONS: FMRI can be used for localizing cortical areas critical to Chinese language processing in the human brain. The results are reliable and well reproducible across different clinical MRI systems.

Adult↗

PubMed2003

[The short-term and long-term treatment outcomes in patients with pulmonary tuberculosis positive for drug-resistant and sensitive strains].

OBJECTIVES: To analyze the treatment outcomes in patients with smear positive tuberculosis, and to compare the difference in treatment response among patients infected with drug-sensitive and drug-resistant strains. METHODS: From 1998 to 2000, seven hundred and seventy-seven patients with primary smear-positive tuberculosis, which were from 30 surveillance sites, were followed for two years to monitor their treatment outcomes. RESULTS: At the completion of the 6 months' therapy, the overall rate of treatment failure was 1.8%, 2.6% for the drug-resistant cases and 1.6% for the drug-sensitive cases. Six-month follow-up showed a positive conversion rate of 2.7% in all the cases, 8.5% and 1.2% (P < 0.005) in the drug-resistant and the drug-sensitive cases respectively. One year follow-up showed that the positive conversion rate was 2.6% in all the cases, 6.9% and 1.6% (P < 0.005) in the drug-resistant and the drug-sensitive cases, respectively. Two-year follow-up showed an overall positive conversion rate of 1.3%, 1.0% and 1.3% in the drug-resistant and the drug-sensitive cases, respectively. Of the 152 drug-resistant cases, the rate of treatment failure was 2.6% at the completion of 6 months' therapy, but in cases with MDR-TB the rate was 10.3%. Six-month follow-up showed an overall positive conversion rate of 8.5%, but the rate reached 37.0% in cases with MDR-TB. One-year and two-year follow-up showed that the positive conversion rates were 6.9% and 1.0% respectively in all the drug-resistant cases, but 6.3% and 6.7% respectively in the MDR cases. CONCLUSIONS: Under the guidelines of the National Tuberculosis Program (NTP), the 2H(3)R(3)S(3)Z(3)/4H(3)R(3) regimen for primary smear-positive pulmonary TB was effective. But the cure rate was lower and the positive conversion rate higher in patients with MDR-TB.

Adolescent↗

PubMed2003

[In vitro and in vivo functional evaluation of anti-human bladder tumor human-mouse chimeric antibody ch-BDI].

OBJECTIVE: To evaluate the in vitro and in vivo function of anti-human bladder tumor human-mouse chimeric antibody ch-BDI and its future clinical application. METHODS: With ch-BDI in high-expression cell-line medium, affinity chromatography was used for the purification. Labeled with (99m)Tc through reduction method, its immunoreactive fraction and association constant were measured. The constant was injected into nude mice with xenografted human bladder tumor. The biodistribution of the labeled ch-BDI was studied with radioimmunoimaging. RESULTS: ch-BDI showed desirable immunoreactive fraction (76%) and association constant (3.56 x 10(9) M(-1)) in vitro and a terrific specific targeting effect in vivo. CONCLUSION: ch-BDI has fairly good function against human bladder tumor both in vitro and in vivo, and is promising in clinical use.

Animals↗

PubMed2003

[The failure causes of non-penetrating trabecular surgery and reoperation].

OBJECTIVE: To study the failure causes of non-penetrating trabecular surgery (NPTS) with SKGeL (a hyaluronic acid biological gel) implant and the surgical method of reoperation. METHODS: Repeated operation with mitomycin (MMC) through the initial surgical site was performed on 13 failure cases (13 eyes) that had undergone NPTS with SKGeL implant. The blockage of filtration tract was removed and the anterior chamber was intact during the surgery. All of these cases were open-angle glaucoma. Before the repeated surgery ultrasound biomicroscopic (UBM) examination was performed on the primary filtering bleb, and the intraocular pressure (IOP) examination was followed after the repeated operation. RESULTS: The mean follow-up period was (14.0 +/- 5.8) months (6 to 24 months). The examination of UBM showed that the filtering bleb disappeared and there was a liquid chamber under the superficial scleral flap in every failure case. The filtration failure due to the scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface in 9 cases, proliferative membrane formation on the trabecular surface in 3 cases, micro-penetration of the trabecula in 1 case. At the end of follow-up, the IOP of 10 cases was lower than 21 mmHg without medication, the mean IOP level was (14.1 +/- 3.7) mm Hg, the IOP of 1 cases was 15 mmHg with Betagen, another 2 cases failed again 6 months after the repeated surgery and underwent the trabeculectomy at last. The complications included hyphema in one case and micro-penetration of the tabecula in one case. CONCLUSIONS: The scarring at conjunctiva-Tenon's capsule-superficial scleral flap interface was the most important cause of NPTS with SKGeL implant failure. A repeated surgery with MMC through the initial surgical site may be a choice for the failure cases.

Adult↗

PubMed2003

[Influences of ration level and initial body weight on growth and size hierarchy of hybrid tilapia, Oreochromis mossambicus x O. niloticus].

72 hybrid tilapia were distributed into twelve tanks, each stocked in six fish (A, B, C, D, E, F) with different body size. The initial body weight was 62.69 +/- 1.46 g for fish A, 56.48 +/- 1.30 g for B, 50.75 +/- 1.19 g for C, 35.56 +/- 1.18 g for D, 31.05 +/- 0.88 g for E, and 27.35 +/- 0.95 g for F (mean +/- SE). The fish were reared under four ration levels (deprived of feed, fed at 1.5% body weight per day (BW.d-1), fed at 3.0% BW.d-1, or fed excess) throughout four weeks, respectively. The specific growth rate (SGR) and feed efficiency (FE) of the fish increased with increasing ration level up to 3.0% BW.d-1, and then, SGR maintained at a constant level while FE dropped with continuing increase of ration. The variance coefficient of SGR and final body weight was relatively high in the fish that fed at 1.5% BW.d-1. For fish A, SGR was not significantly different, between 1.5% BW.d-1, 3.0% BW.d-1 and fed excess, while in fish F, relatively high variations were found among different ration treatments. This experiment revealed that the growth and size hierarchy of hybrid tilapia were related to their ration level and initial body size. Under ration levels more than 3.0% BW.d-1, SGR was usually high, and size hierarchy was relatively weak.

Animals↗

PubMed2003

[Selection of dorsal or volar internal fixation for unstable distal radius fractures].

OBJECTIVE: To assess the results of T-plate in the treatment of unstable distal radius fractures. METHODS: Dorsal or volar T-plate fixation was used for unstable distal radius fractures according to different types of fracture. For comminuted fractures with severe cortex destruction and insufficient buttress, artificial bone graft or autograft was adopted to restore local stability. RESULTS: Satisfactory reduction was achieved after surgery. Functional rehabilitation under surveillance began from the 2nd or 3rd post-operative day. The overall excellent or good recovery rate was 90.77% after a mean follow-up of 29.63 months. For the 55 sides of volar fixation (30 sides with a dorsal displacement fragment), excellent or good recovery rate was 92.72%. Dorsal fixation was used in delayed cases (> 6 weeks) or certain fracture patterns unsuitable for volar approach. The excellent on good recovery rate was 77.77%. CONCLUSIONS: Volar approach is an ideal option not only for distal radius fracture with a volar displaced fragment but also for dorsal displaced fractures (Colles' fracture). The advantages of this approach include flat cortex for easy plate fixation, better tension band effect, less soft tissue destruction, leaving dorsal soft tissue hinge intact, and avoiding bone graft leakage. Satisfactory results can be obtained in those patients with unstable distal radius fracture through volar approach plate fixation, especially in those with fresh fractures. If possible, volar approach can also be used in delayed fractures within 6 weeks. The results of dorsal fixation is a little bit inferior.

Adolescent↗

PubMed2003

[Study on the occurrence of cesarean section (CS) and factors related to CS in China].

OBJECTIVE: To find out the occurrence of cesarean section (CS) and to probe the factors associated with CS. METHODS: Women with CS as "case group" and women without CS as "control group" were chosen in a case-control study. RESULTS: Among 14 071 childbirth women, 6 421 had CS (case group) with the occurrence rate of 45.6% and 7 650 (54.4%) had normal delivery (control group). In comparison with the control group, the CS group had following several higher rates [with significant differences between case group and control group (P < 0.01)]: well-educated (78.9% vs 69.5%), white collar jobs (38.0% vs 32.3%), urban residents (79.1% vs 70.6%), high monthly income (>/= 500 Yuan) (81.0% vs 70.6%), of older age (>/= 25 years) (73.3% vs 63.0%), heavier baby weight (> 4 000 gram) (8.3% vs 2.9%), male babies (53.9% vs 51.4%), BMI of mother (> 24) (8.8% vs 4.8%), cephalopelvic disproportion (21.1% vs 0.9%), intrauterine asphysia (20.3% vs 6.7%), abnormality of force of labor (4.2% vs 2.7%), prolonged labor (2.9% vs 1.0%) and placenta previa (1.4% vs 0.4%). Our study also indicated that the higher the educational level was, the higher the rate of CS appeared; and the older the pregnant women was, the higher the rate of CS was. In CS group, over 70% primipara were over 24 years, and over 20% primipara had cephalopelvic disproportion and over 20% had intrauterine asphysia in CS group. CONCLUSIONS: At present, the occurrence rate of cesarean section was rather high (45.6%) in China. The high rate of CS was more likely to associate not only with abnormal physiological/medical factors (eg. cephalopelvic disproportion, intrauterine asphysia, abnormality of force of labor, and prolonged labour, etc.), but also with some demographic factors as education, occupation, income and age, etc. It is necessary to take measures to reduce the unnecessary CS in China.

Adult↗