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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 433 records · Page 24Linked to original sources
PubMed1997

[Observation of the free calcium of lens epithelial cell using laser scanning confocal microscopy].

OBJECTIVE: Using a new fluorescent Ca++ indicator (fluo-3) and laser scanning confocal microscopy (LSCM) to monitor the intracellular Ca++ of rat lens epithelial cell (LEC). METHODS: The LEC was loaded with fluo-3, then the distribution of free Ca++ in the LEC was observed by using LSCM monitoring the distribution of fluorescence that is given due to the chelation between fluo-3 and Ca++. At last, ionophore (A23187) and heavy-metal ions (Mn++) were applied to calibrate fluo-3 intensities to obtain [Ca++]i value. RESULTS: The free calcium in LEC is mainly located in the nucleus. Free calcium concentration of rat LEC is 259.79 +/- 49.24 nmol/L. CONCLUSION: Fluo-3 can be loaded into LEC by incubation with acetoxymethyl (AM) ester of the dye, and LSCM can be used to observe the cellular free calcium directly by surveying the fluorescence. This method will pave a way technically for the further study of intracellular free Ca++ of the LEC.

Animals↗
PubMed1997

[Calcium mobilization and influx induced by extracellular ATP in the lens epithelial cells].

OBJECTIVE: To examine the effects of extracellular ATP application on the intracellular Ca++ concentration of the in vitro lens epithelial cells (LECs). METHODS: LECs were loaded with fluo-3, then the changes of fluorescent intensities in different conditions were observed by laser scanning confocal microscopy (LSCM). RESULTS: Normal in vitro LECs have strong response to 100 mumol/L ATP and a biphasic wave rise is shown, but LECs have no apparent response to low concentration ATP. When the extracellular calcium chelates to ethylene glycol bis (2-aminoethyl) ether tetracetic acid (EGTA), ATP stimulates the cells and the response is a rapid monophasic rise. CONCLUSION: ATP can induce calcium mobilization and entry into LECs loaded with fluo-3 in a dose-dependent manner. In the LEC membrane, possibly there are P2-purinoceptors.

Adenosine Triphosphate↗
PubMed1997

[Identification of the properties of haptoglobin-like substance in burn serum].

In our previous study, a haptoglobin-like substance possessing immunosuppressive activity was found in the sera of burned patients. However, its properties have not yet been clarified. In the present study, we mainly investigated the properties of the haptoglobin-like substance. The results showed that the abnormal protein bands identified by SDS-PAGE were the different subunits of haptoglobin, i.e., beta, alpha 2 and alpha 1 chains. The haptoglobin in burned sera was identical to that in normal sera in molecular weight, isoelectric point, hemoglobin-binding capacity and immunochemical properties as analyzed by SDS-PAGE, isoelectric focusing, immunochemical and biochemical methods. According to our results, it is suggested that the haptoglobin-like substance reported in the past is probably the haptoglobin, and that there may be no alteration in the properties of haptoglobin following burns.

Animals↗
PubMed1997

[A primary study on antagonizing effects of anti-snake venom Chinese herbs on endothelin-1 and sarafotoxin 6b].

Some anti-snake venom Chinese herbs were used to test the antagonizing effect on ET-1 and S6b. Oral administration has shown that both the water and alcohol extracts from Cissus assamica and Aristolochia fordiana, and the water extracts from Desmodium microphyllum, Cynanthum paniculatum and Polygonum cillinerve are very helpful in reducing the acute death caused by ET-1 and S6b(i.v.), while the extracts from Cissus assamica, Aristolochia fordiana and Cynanthum paniculatum can dilate the vasoconstriction by ET-1 in a dose dependent manner. Pharmacodynamic parameters have shown that the potencies of alcohol extracts from Cissus assamica and Aristolochia fordiana are greater than that of Cynanthum paniculatum. These data suggest that traditional anti-snake venom herbs have antagonizing effects on ET-1.

Animals↗
PubMed1997

[Protective effect of puerarin on acute cerebral ischemia in rats].

Acute incomplete brain ischemia in rats was induced by bilateral carotid artery occlusion(BCAO). BCAO results in severe suppression of EEG and increase of brain water content. Left middle cerebral artery occlusion(MCAO) in rats by electrical coagulation results in increase of brain water content of ipsilateral hemisphere and contralateral hemiparesis. The typical ischemic neuropathological damage emerges in both BCAO and MCAO models. Intraperitoneal injection of puerarin significantly helps improve all these brain ischemic disturbances.

Animals↗
PubMed1997

[Extraction, purification and ascertainment of anti-hepatoma active principles for targeted preparation of radix Aconiti Kusnezoffii].

The extraction, purification, pharmacological experiments and chemical analysis of anti-hepatoma active principles of Radix Aconiti Kusnezoffii have been studied. The results show that the medicinal material Radix Aconiti Kusnezoffii is efficacious in inhibiting hepatoma, and the active principles are mainly made up of poisonous ester alkaloids. The liver targeting delivery system will be the first choice for its anti-hepatoma preparation, and the effective component AY3a is fit for the preparation of targeted microspheres.

Aconitum↗
PubMed1997

Thymic carcinoma (report of 14 cases).

This paper reports of 14 cases of thymic carcinoma. Most of them with symptoms of chest pain, chest stuffy and discomfort, but without combined with extrathoracic syndromes. The tumors always were large in size and frequently invaded adjacent organs, hence with low resection rate. In this series, complete resection of tumor only 2 cases, partial resection in 7 cases, exploratory thoracotomy in 5 cases. Thymic carcinoma was an extremely malignant tumor with extensive invasion intrathoracally and early metastasis extrathoracally. The common sites of metastasis were bone, liver, lung and extrathoracic lymph nodes. Adjuvant therapy postoperatively was given to all patients. Follow-up of 1-8 years showed 10 cases death, of which 5 cases died within the first year after surgery, 3 cases within the second year. Four patients were still alive so far, in which 3 patients were within 1.5 years postoperatively. Pathological studies revealed 9 cases of squamous epithelial cell thymic carcinoma, 3 of lymphoepithelioma-like thymic carcinoma and 2 of small cell undifferentiate thymic carcinoma.

Adult↗
PubMed1997

[A computer-aided design assessment system for recovery life support technology options].

A specific computer-aided decision support system was designed and implemented for design computation and decision assessment of environmental control and life support system of manned space station. An advanced multiobjective decision methodology and a hierarchic structure model of assessment index of recovery life support system was developed. The program incorporates a database for each technology option, metabolic design loads associated with crew activity, mission model variables to accommodate evolving mission requirements, and algorithms to produce products criteria in order to provide recommendations relative to candidate technology selection and development. A specific structure was developed for the decision system which consists of a database, a methodology base and a model base as well as their management systems. Moreover, a centre control system with friendly user interface plays a very important role in the man-computer interaction.

Computer-Aided Design↗
PubMed1997

Experimental study on biodynamic response to vibration in human and animals.

In order to study the characteristics of human dynamic response to vibration, 56 subjects were exposed to vibration on X, Y and Z axes. It showed that there were two resonance peaks of most local parts of the human body. The curves of transmissibility are essentially the same in all the subjects. It was found that resonance frequencies of the human body decreased with increase of G levels of vibration. These characteristics were also proved in animals. Using three-level artificial neural network, common reflective relation of the resonance frequency with height and weight of the human body and exciting acceleration were obtained. The above findings might be applicable to studies of vibration ergonomics.

Acceleration↗
PubMed1997

[Sequence analysis of 5' non-coding region of hepatitis G viruses and preliminary classification of genotypes].

For analyzing the structural characteristics of hepatitis G virus (HGV or GBV-C), 277 nucleic acids of 5' non-coding region of HGV were amplified using PCR from the sera of 2 paid donors, 2 chronic hepatitis patients and 2 patients with liver cirrohsis. The products were cloned and sequenced. The data were analyzed with the computer programs. The results indicated that the gene sequence homologies among 6 HGV isolates (G001-G006) obtained in this study were above 96.2%. The comparison of these 6 isolates and 3 foreign isolates reported previously showed that the sequence homologies were in the range from 86.9% to 91.6%. According to the variability of gene sequences, the preliminary division of genotypes of 6 Chinese HGV isolates (G001-G006) and 3 isolates reported abroad were classified into three distinct groups. The results suggest that the gene sequences of Chinese HGV isolates are highly homologous but have an obvious divergence with the foreign isolates. The 5' untranslated regions of all isolates analyzed probably contain a stable and similar secondary structure.

5' Untranslated Regions↗
PubMed1997

[The cloning and sequence analysis of cDNA of the partial E genomic region of Dengue type 4 virus from a Chinese patient].

The partial envelope (E) protein gene of Dengue virus type 4 (DV4), derived from the serum of a patient with dengue fever in an epidemic during October 1993 in Guangdong Province of China, was cloned and sequenced. DV RNA was converted to cDNA by reverse transcription with random primers before the polymerase chain reaction using DV4 specific primers was performed. The amplified product of 421bp was subsequently filled in 3' recessed ends, isolated, purified and inserted into pUC18 and pUC19 plasmid vector. Their sequences were determined by dideoxy nucleotide chain termination method. A comparison between DV4 Chinese strain and several other previously reported strains shows the homology to be 93.72% for the same dengue serotype, 61.26-64.40% for the other dengue serotypes, only 40.31% for Japanese encephalitis virus, which belongs to the member of flavivirus family. A conserved sequence with 12 amino acids observed from deduced protein sequence probably represents an essential functional element among flavivirus family.

Amino Acid Sequence↗
PubMed1997

[Dual wavelength multiplication subtractive spectrophotometric determination of sulfadiazinum and trimethoprimum in compound sulfadiazine tablets].

This paper described the simultaneous determination of sulfadiazine (SD) and trimethoprim (TMP) in tablets co-Trimediazini by dual wavelength spectrophotometry multriplication subtractive method. This method was based on the measurement of both absorbance of standard solution of SD (8-14) x 10(-6)g/mL, TMP (1-2) x 10(-6)g/mL and sample solution at wavelength 242.5 nm and 228.0nm. The average recovery and RSD of SD and TMP were 100.60%, 0.33% and 98.27%, 1.58%, respectively (n=20). The method was simple, quick and results satisfactory.

Drug Combinations↗
PubMed1997

[Investigation of fluorescence spectra of alum floc].

The sharp fluorescence peak of alum floc was observed at 340nm. The peak height at 340nm is in proportion to alum concentration under same degree of neutralization. There is similar regular change of this peak height as change of neutralization degree under different alum concentration.

English Abstract↗
PubMed1997

Elements between the protein-coding regions of the adjacent beta 4 and alpha 3 acetylcholine receptor genes direct neuron-specific expression in the central nervous system.

The expression patterns of three clustered neuronal nicotinic acetylcholine receptor (nAchR) subunit genes ordered beta 4, alpha 3, and alpha 5 overlap extensively in the peripheral nervous system (PNS) but only partially in the central nervous system (CNS). We have begun to investigate cell type-specific cis elements regulating these genes by analyzing in both cell culture and transgenic mice, a 2.8-kb fragment (-2732/+47) containing the alpha 3 promoter region, the beta 4/alpha 3 intergenic region, and a portion of the beta 4 3'-untranslated exon. The -2732/+47 fragment is preferentially active in PC12 cells relative to nonneural cell lines. Deletion analysis revealed a cell type-specific positive transcriptional element positioned in the beta 4 3'-untranslated exon. The positive element is likely to be an enhancer and not a second alpha 3 promoter, because no alpha 3 exons are present in this region. Having shown in cell culture that cell-type specific cis elements are positioned between the beta 4 and alpha 3 coding regions, we investigated the activity of -2732/+47 in vivo. Transgenic mice were generated, which carry the lacZ gene fused downstream of -2732/+47. Expression of the lacZ transgene is restricted to neurons of the CNS; no expression was detected in the PNS or in nonneural tissues. LacZ-positive cells were detected virtually exclusively in a subset of CNS nuclei that transcribe the endogenous alpha 3 gene. Some overlap was seen with the beta 4 gene, but nearly none with the alpha 5 gene. Our results demonstrate that cis elements positioned between the alpha 3 and beta 4 coding regions are important for establishing part of the restricted CNS patterns of beta 4, alpha 3, and alpha 5 gene transcription.

Animals↗
PubMed1997

Identification of viable myocardium early after acute myocardial infarction under beta-blockade by enoximone echocardiography.

The influence of the beta-blocker metoprolol on the capacity either of low-dose dobutamine echocardiography or the recently introduced enoximone echocardiography to detect viable dysfunctioning myocardium after myocardial infarction was investigated. Initial clinical experience would suggest that the phosphodiesterase III inhibitor enoximona could be an alternative pharmacological stimulation, inducing an increase in contractility in the presence or absence of beta-receptor stimulation. Ten patients with a baseline low-dose dobutamine-echocardiographic test (up to 10 micrograms/kg/min) positive for myocardial viability in > or = 1 segment(s), performed 4-5 days after a first acute myocardial infarction treated with rtPA, were randomized after the administration of intravenous metoprolol (15 mg in three 5-mg boluses) either to dobutamine (up to 15 micrograms/kg/min) or to an enoximone intravenous bolus (1 mg/kg over 5 min) under echocardiographic monitoring, in a crossover sequence, with a 24-h interval. The infarct related artery was patent (TIMI grade 2 o 3) in all the patients. Follow-up echocardiograms were performed 5-7 weeks later. Resting asynergy was found in 40 segments; of these, 17 were viable. All the viable segments remained unresponsive during the post-metoprolol dobutamine infusion, while improved their contractility during enoximone echocardiography. Two patients suffering from early post-infarction angina underwent coronary angioplasty successfully. Eight out of ten patients (2 revascularized and 6 not) showed contractile recovery in a total of 14 segments at the follow-up echocardiogram. Sensitivity, specificity and overall accuracy in predicting reversible dysfunction after acute myocardial infarction for enoximone echocardiography were 93, 85, and 88%, respectively. Our results support the value of enoximone echocardiography in the identification of myocardial viability after myocardial infarction, in patients treated with beta-blockers, which interfere heavily with the results of dobutamine echocardiography.

Acute Disease↗
PubMed1997

Chronic nicotine exposure differentially affects the function of human alpha3, alpha4, and alpha7 neuronal nicotinic receptor subtypes.

Because chronic exposure to nicotine and nicotinic drugs might both activate and desensitize nicotinic acetylcholine receptors (AChRs), we sought to determine whether prolonged exposure to nicotine concentrations encountered in tobacco users differentially affects electrophysiological properties of major subtypes of human neuronal nicotinic AChRs. Xenopus laevis oocytes were injected with subunit cRNAs encoding (1) homomeric alpha7 AChRs, (2) heteromeric alpha4beta2 AChRs and (3) heteromeric alpha3 AChRs formed from combinations of alpha3, beta2, beta4 and alpha5 cRNAs. Acute activation required micromolar concentrations of nicotine. Chronic exposure to submicromolar concentrations of nicotine irreversibly inactivated many alpha4beta2 AChRs and alpha7 AChRs but inhibited alpha3 AChRs much less. Thus, although alpha3 AChRs are present in the brain in much smaller amounts than are alpha4beta2 AChRs or alpha7 AChRs, alpha3 AChRs in brain and autonomic ganglia may be able to play a relatively large role in acute responses to endogenous ACh or subsequent doses of nicotine after chronic exposure to nicotine. The behavioral effects of nicotine may typically reflect the sustained inhibition of alpha4beta2 AChRs and alpha7 AChRs in combination with the residual susceptibility of alpha3 AChRs and perhaps some other AChR subtypes for acute activation. Tolerance for nicotine exhibited by tobacco users may reflect the long-term irreversible functional inactivation of alpha4beta2 AChRs and alpha7 AChRs produced by chronic exposure to nicotine.

Animals↗
PubMed1997

Functional measurement of nonfibrotic hepatic mass in cirrhotic patients.

OBJECTIVES: We have postulated that the perfused hepatic mass (PHM) can be estimated by quantitative (volumetric) liver spleen scan (QLSS) using single photon emission computed tomography assessment of sulfur colloid distribution between liver, spleen, and bone marrow. Thus, this parameter should correlate with the amount of functioning tissue in the liver. As a "gold standard" estimate of the nonfibrotic functioning hepatic mass, the weight of the liver at autopsy or transplant was corrected for the amount of scar tissue present. QLSS parameters were correlated with functional hepatic mass in 13 patients with advanced liver disease with liver available at transplant (8 patients) or autopsy (5 patients) who had prior QLSS. METHODS: Greater than 1000 mm2 of a liver tissue was assessed histologically in all patients and from more than 2 regions of the liver in 9 of 13 patients. The total fibrosis score (TFS) (range, 0-17.5) was calculated as a semiquantitative estimate of hepatic fibrosis. The ratio of functioning tissue was calculated as (1 - TFS/20) and the amount of functioning tissue as the nonfibrotic weight (NFW): NFW = liver weight x (1--TFS/20). QLSS parameters were measured postprandially and 30 min after injection of 5 mCi of technetium Tc 99m sulfur colloid. Pixel and total counts from the liver, spleen, and bone marrow as well as organ length were measured. Liver/bone marrow index and liver/spleen index were calculated. The perfused hepatic mass (PHM) was defined as the mean of the liver/bone marrow index and liver/spleen index. RESULTS: All patients had cirrhosis: alcoholic (1 patient), alcoholic with alcoholic hepatitis (1 patient), hepatitis B (3 patients), hepatitis C (6 patients), hepatitis C with hepatocellular carcinoma (1 patient), and primary sclerosing cholangitis (n = 1). The ratio of functioning tissue was 0.54 +/- 0.07; liver weight 1215 +/- 317 g; and NFW = 658 +/- 193 g. The PHM = 55 +/- 14. The PHM calculated from the QLSS correlated strongly with the NFW (functioning tissue) at autopsy/transplant: NFW = 13 PHM - 55; r = 0.9505; p < 0.0001). CONCLUSIONS: In cirrhotic patients (a) we have confirmed that the sulfur colloid distribution by QLSS is determined by the perfused hepatic mass, and (b) the amount of functioning tissue can be precisely estimated by QLSS parameters.

Autopsy↗