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Biomedical subjects

J Bai

Publications and source records attributed to J Bai.

At least 127 records · Page 7Linked to original sources
PubMed1997

[The study of women's bone density in Beijing].

Bone mass of 434 healthy women aged from 20-65 years was measured at both distal and mid-radius of the non-dominant arm by using a single-photon absorptiometer (SPA) with an 241Am source (model SD-1000), and bone density and related factors were studied. The bone density in women reached the peak value around 40 years old and the bone loss began around 45 years old. Bone loss was accelerated after menopause, with faster speed in trabecular bone than in cortical bone. The effect of menopause on bone loss was more significant than the effect of advancing age. Among 174 menopausal women, 9.8% had fractures. The bone density of postmenopausal women with history of bone fracture was lower than that of those without fracture. The results of this study suggest that the measurement of bone density can be used to predict the risk of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1997

[Effects of the glucoprotein component of musk on the functions of rat polymorphonuclear leukocytes activated by fMLP in vitro].

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on the release of superoxide anion as well as beta-glucuronidase and lysozyme of rat polymorphonuclear leukocytes activated by fMLP. An in vitro incubation system with rat polymorphonuclear leukocytes was used. Superoxide anion production was determined by cytochrome C reduction. beta-glucuronidase and lysozyme release was quantitated by enzyme reactions in which phenolphthaleinglucuronic acid and micrococcus lysodeikticus were as the substrates, respectively. In comparison with control, musk-1 at final concentrations of 1-100 micrograms/ml can increase superoxide anion production by 23.0%-83.6% and decrease beta-glucuronidase and lysozyme release by 7%-47% and 9%-22%, respectively, in rat polymorphonuclear leukocytes. It is concluded that Musk-1 can significantly affect the functions of rat polymorphonuclear leukocytes. Therefore, inhibition of lysosomal enzyme release might be considered as one of the mechanisms of anti-inflammatory role of musk.

Animals↗
PubMed1997

[The effect of glucoprotein component of musk on arachidonic acid metabolizing enzymes in rat polymorphonuclear leukocytes].

To investigate the effects of musk-1, a glucoprotein component isolated from the water extract of musk, on arachidonic acid metabolizing enzymes, which include phospholipase A2(PLA2), 5-lipoxygenase (5-LO), and cyclooxygenase (COX), in rat polymorphonuclear leukocytes, an in vitro incubation system with rat polymorphonuclear leukocytes or homogenate supernatant of the same cells was used. In comparison with control, musk-1 at final concentrations of 1-100 micrograms/ml can increase AA release from PMNL by 6.0%-21.6%, decrease LTB4 biosynthesis in homogenate supernatant of the cells by 9%-81%, but increase 6-keto-PGF1 alpha production by 18.2%-85.4%.

6-Ketoprostaglandin F1 alpha↗
PubMed1997

[A simulation study on G protection using tilt-back seat].

A mathematical model of human cardiovascular system with cardiopulmonary interaction was developed basing on the previous works of Jaron, Bai jing, et al (1988, 1992). The model of pulmonary circulation was improved and intrathoracic pressure, intra-abdominal pressure and pulmonary alveolar pressure were introduced in the new model. Computer simulation experiments using this model for human relaxed tolerance to rapid onset (1 G/s), gradual onset (0.1 G/s), and high onset (5 G/s) G exposures, at seat back angles of 13 degrees, 30 degrees, 45 degrees, 55 degrees, 65 degrees, 75 degrees, and 85 degrees, were performed. The simulation results are consistent with the experimental data obtained from reported centrifuge experiments. The tolerance increase by tilt back seat may be attributed to the following three factors: (1) decrease of retinal-aorta hydrostatic distance; (2)decrease of venous pooling in the lower body; (3)decrease of G onset rate in Z axis.

Acceleration↗
PubMed1997

[Simulation study on the blood volume feedback control].

To describe the relationship between blood volume and the cardiac function mathematically, a computer cardiovascular model, was developed including a systemic circulation, a heart and a pulmonary model and a blood volume feedback control. Simulation results indicate that the chronic heart failure could be compensated by increasing the blood volume to maintain the proper arterial pressure. Deterioration in heart failure causes an increase in blood volume, as well as increases in heart volume and cardiac energy consumption. These results are in agreement with the clinical data and results reported in the literature. The simulation also shows that for a predetermined ventricular contractility, an adequate increase in blood volume will increase the heart volume but decrease the cardiac energy consumption and lead the heart to work in an optimum condition.

Aerospace Medicine↗
PubMed1997

Simulation study of the interaction between respiration and the cardiovascular system.

Many studies have been done on the respiratory and the cardiovascular system. Among them, only a few are on the interaction of these two physiologic systems. To explore the mechanism of the integration of these two physiological systems, computer simulation has been done; we report the preliminary results obtained in our laboratory. In this study, a mathematical model of the cardiovascular system integrated with the respiratory mechanical system has been established. The model is based on our previous work on cardiovascular modeling. The previous lumped lung model has been replaced by a multielement model with more detail. Interthoracic and abdominal pressures and modeled as external pressure sources on the related cardiovascular elements. Using this model, a sequence of simulation studies have been carried out. Different respiratory modes have been simulated and the different effects are observed in the simulation results. The results indicate that by following a certain respiratory pattern, the circulation status can be improved. These results agree with clinical observations.

Cardiovascular Physiological Phenomena↗
PubMed1997

[The monitoring of post cesarean section uterine scal with B-ultrasonographic and clinical detections].

OBJECTIVE: To find out an effective method for monitoring the healing of uterine incision after cesarean section. METHODS: 1,145 patients with cesarean section were monitored by B-ultrasonography. In 19 patients who revealed fluid mass in uterine incision, 10 cases were treated by percutaneous drainage under sonographic guidance and 9 cases as control. RESULTS: According to sonographic characteristics, uterine incision healing can be divided into three conditions: normal type revealing a smooth strong echo's light band in uterine incision (93.97%), inflammatory type revealing an uneven parenchymatous light mass (3.67%), and fluid mass with inflammation revealing a complex light mass with low echo's or anechoic area (2.36%). There were abnormal clinical signs in most cases of inflammation. The percutaneous drainage therapy showed marked effect. CONCLUSIONS: The monitoring of uterine incision healing by B-ultrasonography plays an important role in preventing late post-partum hemorrhage.

Cesarean Section↗
PubMed1997

[The therapeutic effect of purified human leucocytic interferon-alpha on hemorrhagic fever with renal syndrome].

In order to know the therapeutic effect of purified human leucocytic interferon-alpha on hemorrhagic fever with renal syndrome diagnosed early (< or = 5 days). We treated 23 cases with clinical prognosis and antiviral effect significantly better than those of 21 cases in a random control group. The membrane protein (MP), nucleo protein (NP) in peripheral blood mononuclear cells (PBMC) and urine, the serum antibodies to MP and NP were determined before treatment and 2, 4, 6, 8, 10 days after the beginning of the treatment. The results showed that in the treatment group, the expressin of MP and NP in PBMC were significantly depressed. The rate of negative turning of MP and NP in PBMC was 65.22% (15/23) and 69.57% (16/23) in 10 days, while in the control group, it was 19.05% (4/21) and 14.29% (3/21). The rate of negative turning of MP and NP in urine were 78.57% (11/14) and 90.91% (10/11) and that in the control group was 30.00% (3/10) and 16.66% (1/6). There was a significant difference between the two groups (P < 0.01). The results indicated that IFN-alpha could attenuate the lesions caused directly by virus, improve patients condition and raise the cure rate through depressing the expression of the virus.

Adult↗
PubMed1997

[Effect of Salvia miltiorrhizae Composita on erythrocyte membrane phospholipid in patients with coronary heart disease].

OBJECTIVE: To investigate the function of phospholipid metabolism in pathogenesis of coronary heart disease (CHD) and the effect of Salvia miltiorrhizae Composita (SMC) on it. METHODS: The levels of erythrocyte membrane phospholipid, blood lipid peroxide (LPO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined in the patients with CHD by Thinlayer chromatography and fluorimetry during the treatment of SMC. RESULTS: Sphingomyelins (SM), phosphatidyl serine (PS), phosphatidyl ethanolamine (PE) and lysophosphatide (LL) of erythrocyte membrane phospholipid were increased in patients with CHD. Phosphatidyl cholines (PC) was lower than control group. Among them, the ratios of SM/PC and PS/PC were significantly higher. In the patients with CHD, LPO was significantly increased and ratios of SOD/LPO and GSH-Px/LPO significantly decreased. After the treatment with SMC, LL, SM, PS and PE of erythrocyte phospholipid and the ratios of SM/PC and PS/PC and LPO were decreased. PC and SOD/LPO were increased. CONCLUSIONS: The abnormality of erythrocyte membrane phospholipid participate the occurrence and development of CHD. SMC might improve the abnormality of erythrocyte phospholipid and lipid peroxide and possess the effect of regulating phospholipid metabolism.

Adult↗
PubMed1996

Characterization of SDS--PAGE-separated proteins by matrix-assisted laser desorption/ionization mass spectrometry.

A new strategy to characterize SDS--PAGE-separated proteins with MALDI MS is described. The proteins, electroblotted onto nitrocellulose after SDS--PAGE separation and stained with reversible Ponceau S dye, are readily recovered by dissolving the membrane in matrix solutions prepared with acetone. The resulting mixtures are amenable to direct MALDI MS analysis, which provides a rapid and accurate means of measuring the molecular weights of SDS--PAGE-separated proteins and of peptides that result from CNBr digestion of proteins on the nitrocellulose membrane. Compared with the traditional elution method, this procedure provides more efficient detection of proteins and peptides, especially the higher molecular weight proteins from the membrane. As little as 3.5 pmol of lysozyme and 15 pmol of bovine albumin loaded onto a gel can be detected using this method. The detection sensitivity is higher than or comparable to that of the traditional Coomassie Brilliant Blue staining procedure.

Electrophoresis, Polyacrylamide Gel↗
PubMed1996

Characterization of two new matrices for matrix-assisted laser desorption/ionization mass spectrometry.

Three structurally related compounds, 4-hydroxy-33-methoxyphenylpyruvic acid (HMPPA), indole-3 pyruvic acid (IPA), and indole-3-glyoxylic acid have been evaluated as matrix-assisted laser desorption/ionization (MALDI) matrices. HMPPA and IPA were found to be effective matrices for MALDI-MS analysis of proteins and peptides and have been characterized in this work. HMPPA was found to be a particularly good matrix for the analysis of proteins and peptides because of its tolerance towards impurities and the resulting sensitivity in MALDI-MS experiments. Analysis of model proteins and peptides, including those in biological fluid, are demonstrated.

Glyoxylates↗
PubMed1996

The effects of intra-aortic balloon pumping combined with coronary sinus interventions on failing hearts: a model study.

Cardiac energy balance is an important factor in evaluating cardiac function. In this work, the effects of different assist modalities and their combinations on cardiac energy balance and global cardiac function have been investigated. The simulation results indicate that coronary sinus interventions (CSIs) can provide myocardium with more energy than IABP when coronary arterial stenosis is serious. However, IABP can decrease myocardial energy consumption and enhance cardiac output, which cannot be done by CSIs, under the condition of impaired myocardial contractility. Therefore, we conclude that the combination of IABP and CSIs is the best way of assisting failing circulation.

Animals↗
PubMed1996

Splenic hypofunction in cirrhosis is not associated with increased risk for infections.

BACKGROUND/AIM: Pitted cell count has been described as a sensitive marker of splenic function. Recently, pitted cell count was shown to be increased in patients with alcoholic liver disease, and also to be associated with an increased susceptibility to infection. Therefore, our aim in the present study was to assess splenic function in a group of patients with cirrhosis and to determine its possible role in the development of infections. METHODS: Splenic function was assessed during hospitalization in 44 patients diagnosed as having cirrhosis, and was compared to 18 healthy subjects. Function was evaluated by counting the number of pitted cells in peripheral blood films. Results were the mean value of two independent counts and were expressed as number of pitted cells/100 erythrocytes. RESULTS: The mean percentage of pitted cells in peripheral blood of cirrhotic patients was significantly greater than that assessed in controls (3.5 +/- 3.7% vs. 1.6 +/- 0.9%, P < 0.01, Mann-Whitney U test). Eighteen patients with cirrhosis (36%) had counts greater than 3.4% (mean + 2 SD of the control group). There were no significant differences between patients with counts above or below 3.4% in terms of liver tests, platelet and reticulocyte counts, the presence of complications, Child-Pugh score and the prevalence of infections. There was no difference in pitted cell count between alcoholic and non-alcoholic cirrhotic patients (3.8 +/- 3.4% vs. 3.1 +/- 2.8% respectively, P, NS). Moreover, the mortality rate and the occurrence of infections were similar in patients with normal and increased pitted cell counts during 1-year follow-up. CONCLUSION: The increased number of pitted cells in patients with cirrhosis is not related to heptic function and does not represent a risk factor for infections.

Adult↗
PubMed1996

The exogenous form of Jaagsiekte retrovirus is specifically associated with a contagious lung cancer of sheep.

Sheep pulmonary adenomatosis ([SPA] ovine pulmonary carcinoma) is a transmissible lung cancer of sheep that has been associated etiologically with a type D- and B-related retrovirus (jaagsiekte retrovirus (JSRV]). To date it has been impossible to cultivate JSRV in vitro and therefore to demonstrate the etiology of SPA by a classical approach. In addition, the presence of 15 to 20 copies of endogenous JSRV-related sequences (enJSRV) has hampered studies at the molecular level. The aim of this study was to investigate whether the expression of exogenous JSRV was specifically associated with neoplasia in SPA-affected animals. Initially, we found that enJSRVs were transcribed in a wide variety of normal sheep tissues. Then, by sequencing part of the gag gene of enJSRV we established a ScaI restriction site in gag as a molecular marker for the exogenous form of JSRV. Restriction enzyme digestion of PCR products obtained from the amplification of cDNA from a total of 65 tissues collected from SPA-affected and unaffected control sheep revealed that the exogenous form of JSRV was exclusively and consistently present in tumor tissues and lung secretions of the affected animals. In addition, exogenous JSRV provirus was detected only in DNA from SPA tumors and not from nontumor tissues of the same animals. This study has demonstrated clearly that the exogenous form of JSRV is specifically associated with SPA tumors.

Animals↗
PubMed1996

Unique long terminal repeat U3 sequences distinguish exogenous jaagsiekte sheep retroviruses associated with ovine pulmonary carcinoma from endogenous loci in the sheep genome.

Ovine pulmonary carcinoma (OPC) is a contagious lung cancer of sheep that is presumed to be caused by an exogenous retrovirus of sheep, jaagsiekte sheep retrovirus (JSRV). The sheep genome carries 15 to 20 copies of endogenous sheep retrovirus (ESRV) loci that hybridize to JSRV DNA probes. In order to clarity the etiologic roles of ESRV and an exogenous JSRV-like retrovirus (exJSRV) in OPC, we assessed sequence differences between ESRV and JSRV. Molecular characterization of six ESRV loci revealed restriction sites specific for JSRV. Nucleotide sequences of ESRVs from sheep of different breeds were similar to those of JSRV in structural genes but divergent in U3. Therefore, primers specific for the U3 sequences of exJSRV were designed for use in the PCR. Of 13 tumor DNAs tested by PCR with these exogenous-virus U3 primers, 8 produced DNA fragments that hybridized with the JSRV gag probe, but neither lung DNAs from healthy sheep nor DNAs from nontumor tissues of diseased sheep produced similar DNA fragments. exJSRV PCR products from tumor DNAs of sheep with OPC from three continents had restriction profiles similar to each other but different from those of ESRVs upon digestion with EcoRI, HindIII, NdeI, KpnI, and ScaI. These exjSRVs could be classified into two genotypes according to U3 sequences and restriction profiles. U3 sequences of exJSRV proviruses in tumors strongly resembled those of JSRV but differed from those of ESRVs, suggesting that exJSRVs, rather than ESRVs, are primarily associated with oncogenesis in OPC.

Amino Acid Sequence↗
PubMed1996

The design and preliminary evaluation of a home electrocardiography and blood pressure monitoring network.

A home electrocardiography (ECG) and blood pressure (BP) monitoring network was established in Beijing. The network consisted of three parts: (1) the home ECG and BP monitoring devices; (2) the monitoring centre at the hospital; and (3) the data communication network, for which we chose the public telephone network. The system was tested in our university hospital for two months with 30 patients and six normal volunteers. A preliminary evaluation by the users indicated that the system was acceptable in terms of its efficiency and effectiveness. This paper describes the system design, the preliminary testing procedure, and results.

Adult↗
PubMed1995

Use of a nitrocellulose film substrate in matrix-assisted laser desorption/ionization mass spectrometry for DNA mapping and screening.

A nitrocellulose film is used as a substrate in matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) studies of DNA. PCR products and DNA fragment digests obtained from biochemical procedures can be analyzed with the use of a nitrocellulose substrate in MALDI MS whereas no signal is observed with the use of a stainless steel substrate. In this method, on-probe purification allows for effective elimination of the interfering effects of salts, buffers, and other contaminants that are usually present in DNA samples, which serve as important limiting factors in the DNA molecular ion yield in the MALDI process. The use of the nitrocellulose film substrate also appears to improve the shot-to-shot and sample-to-sample reproducibility of the ion yield due to the more homogeneous coverage of matrix/analyte over the sample surface. With the use of the nitrocellulose substrate, DNA fragments of up to 622 base pairs in complex mixtures provide mass spectra with minimal sample purification. Although only species corresponding to single-stranded DNA were detected, a mass calibration scheme was established allowing an accuracy of within one base pair for fragments of < 250 bp under the experimental conditions. Despite the low mass resolution of the spectra obtained, the method has been successfully used for rapid DNA screening for sample disease genes and PCR products.

Base Sequence↗