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Biomedical subjects

W Liang

Publications and source records attributed to W Liang.

At least 55 records · Page 3Linked to original sources
PubMed1999

[The research of evaluation the compatibility of biotic material in cell-culturing method].

It is quick convienent good-repeating and cheap that examining the biotic material's compatibility through cell-culturing method, and it is more and more important in evaluating the compatibility of biotic material. The new material appearing continously complicating of the part and aim material be planted in the intensity of material's toxic effect the reaction's complication of material and biotic body, all of these decide the variety of experiment method and cells in cell toxicity experiment. It is very important that choices the right experiment method and cells according to the material's character the part and aim the material be planted in. The evaluation of biotic material's compatibility stressed on the changing of cell's form and quantity before. In recent years, more and more reports appear about material influences the growth. Adhesion proliferation and metabolizing of cell, and presents the point that the evaluation standard of biotic material's compatibility should be set according to the active cell's quantity and their growth. Combining many subject's technological development, such as immunology, chemistry, radiation and shadowgraphy, thoroughly inquires the changing relation of cell's structure and function, furtherly clarifes the material's effect on cell. It is the developing direction in the future that evaluates the biotic material's compatibility in cell-culturing method.

Cell Culture Techniques↗
PubMed1999

[Fraction P isolated from the ribosomes of Serratia odorifera and its tumor inhibiting effect].

A protein(component P) with molecular weight of 16 kD was isolated by the method of preparation electrophoresis from the ribosomes of Serratia odorifera, which were obtained by the method of differential centrifugation. This protein showed specific immune response reactivity with the antiserum of the ribosomes mentioned above. Meanwhile, component P showed apparent protective function for QGY-tumorcharged nude mouse and different ways of giving medicine. It was evident from study results that component P isolated from the ribosomes of Serratia odorifera showed a direct function for tumor growth inhibition and it was the effective component of the ribosomes of Serratia odorifera.

Animals↗
PubMed1998

Serendipity in diagnostic imaging: magnetic resonance imaging of the breast.

BACKGROUND: Magnetic resonance imaging (MRI) of the breast has been proposed as a noninvasive diagnostic test for evaluation of suspicious ("index") lesions noted on mammography and/or clinical breast examination (CBE). However, women may have incidental ("serendipitous") lesions detected by MRI that are not found on mammography or CBE. To understand better whether or not biopsy procedures should be performed to evaluate serendipitous lesions, we estimated the breast cancer risk for women with this type of lesion. METHODS: A decision analysis model was used to estimate the positive predictive value (i.e., the chance that a woman with a serendipitous lesion has cancer) of MRI for serendipitous lesions in women who had an abnormal mammogram and/or CBE suspicious for cancer (where a biopsy procedure is recommended). We restricted the analysis to data from women whose index lesions were noncancerous and used meta-analysis of published medical literature to determine the likelihood ratios (measures of how test results change the probability of having cancer) for MRI and the combination of CBE and mammography. The positive predictive value of MRI was calculated using the U.S. population prevalence of cancer (derived from registry data) and the likelihood ratios of the diagnostic tests. RESULTS: Under a wide variety of assumptions, the positive predictive value of MRI was extremely low for serendipitous lesions. For instance, assuming sensitivity and specificity values for MRI of 95.6% and 68.6%, respectively, approximately four of 1000 55- to 59-year-old women with serendipitous lesions would be expected to have cancer (positive predictive value = 0.44%, 95% confidence interval = 0.24%-0.67%). CONCLUSION: In women with a suspicious lesion discovered by mammography and/or CBE that is found to be benign, serendipitous breast lesions detected by MRI are extremely unlikely to represent invasive breast cancer. Immediate biopsy of such serendipitous lesions may, therefore, not be required.

Adult↗
PubMed1998

Monolayer Behavior of Tetraphenylporphyrin Derivatives Containing Four Fluorocarbon Chains and Optical Properties of Their Monolayer Assemblies.

For tetraphenylporphyrin derivatives substituted with four fluorocarbon chains (TFPP), monolayers on the water surface were studied with the Brewster angle microscope together with pressure-area curves. It was found that heterogeneous aggregated structures of the monolayers were dependent upon the chain length of fluorocarbons, the metal-free or Mn-TFPP, and the periods after spreading. Polarized UV-visible spectra for the monolayer assemblies indicated that the porphyrin rings in the films were tilted on the average, but had a tendency to adopt an orientation more parallel to the water surface as the chain length of the fluorocarbon increased. The third-order nonlinear optical susceptibility for the monolayer assembly of TFPP with the shorter chains was found to be 7.0 x 10(-13) esu, and those of Mn-TFPP were enlarged. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Nucleotide-dependent conformational change near the fulcrum region in Dictyostelium myosin II.

In skeletal muscle myosin, the reactive thiols (SH1 and SH2) are close to a proposed fulcrum region that is thought to undergo a large conformational change. The reactive thiol region is thought to transmit the conformational changes induced by the actin-myosin-ATP interactions to the lever arm, which amplifies the power stroke. In skeletal muscle myosin, SH1 and SH2 can be chemically cross-linked in the presence of nucleotide, trapping the nucleotide in its pocket. Although the flexibility of the reactive thiol region has been well studied in skeletal muscle myosin, crystal structures of truncated nonmuscle myosin II from Dictyostelium in the presence of various ATP analogs do not show changes at the reactive thiol region that would be consistent with the SH1-SH2 cross-linking observed for muscle myosin. To examine the dynamics of the reactive thiol region in Dictyostelium myosin II, we have examined a modified myosin II that has cysteines at the muscle myosin SH1 and SH2 positions. This myosin is specifically cross-linked at SH1-SH2 by a chemical cross-linker in the presence of ADP, but not in its absence. Furthermore, the cross-linked species traps the nucleotide, as in the case of muscle myosin. Thus, the Dictyostelium myosin II shares the same dynamic behavior in the fulcrum region of the molecule as the skeletal muscle myosin. This result emphasizes the importance of nucleotide-dependent changes in this part of the molecule.

Actins↗
PubMed1998

Methionine enkephalin immunoreactivity in the brain of the budgerigar (Melopsittacus undulatus): similarities and differences with respect to oscine songbirds.

The brain of the budgerigar (Melopsittacus undulatus), a small parrot that acquires new vocalizations throughout life, was examined for immunoreactivity to the opioid peptide methionine enkephalin (mENK). mENK is a highly prominent feature of the chemical architecture of the forebrain vocal system of oscine songbirds. Forebrain vocal control nuclei are believed to have evolved independently in parrots and songbirds (Streidter [1994] J. Comp. Neurol. 343:35-56); however, recent studies have found similarities in the neural organization of vocal control pathways in budgerigars and songbirds (Durand et al. [1997] J. Comp. Neurol. 377:179-206). Among the similarities are the existence of recursive pathways interconnecting vocal control neurons in the archistriatum, basal ganglia (i.e., lobus parolfactorius), and dorsal thalamus. In the present study, we found that all vocal control nuclei within the budgerigar forebrain exhibit prominent mENK-like immunoreactivity (ELI) in fibers and somata. We also found striking similarities between the morphology of ELI elements in budgerigar vocal control nuclei and that described previously in songbird vocal nuclei. Despite these similarities, the budgerigar dorsal striatopallidum (lobus parolfactorius, paleostriatum augmentatum, and paleostriatum primitivum) and somatomotor (anterior) archistriatum exhibit unique patterns of ELI. The dorsal striatopallidum contained far less ELI, whereas the archistriatum contained far more than would be expected on the basis of previous studies of opioid peptides in other avian species, including pigeons, chickens, and songbirds. These differences may reflect neural specializations unique to the budgerigar that contribute to the extraordinary flexibility of the vocal motor system of this species to acquire socially significant stimuli throughout life.

Animals↗
PubMed1998

Matrix metalloproteinase inhibitors: a structure-activity study.

Modifications around the dipeptide-mimetic core of a hydroxamic acid based matrix metalloproteinase inhibitor were studied. These variations incorporated a variety of natural, unnatural, and synthetic amino acids in addition to modifications of the P1' and P3' substituents. The results of this study indicate the following structural requirements: (1) Two key hydrogen bonds must be present between the enzyme and potent substrates. (2) Potent inhibitors must possess strong zinc-binding functionalities. (3) The potential importance of the hydrophobic group at position R3 as illustrated by its ability to impart greater relative potency against stromelysin when larger hydrophobic groups are used. (4) Requirements surrounding the nature of the amino acid appear to be more restrictive for stromelysin than for neutrophil collagenase, 72 kDa gelatinase, and 92 kDa gelatinase. These requirements may involve planar fused-ring aryl systems and possibly hydrogen-bonding capabilities.

Chromatography, High Pressure Liquid↗
PubMed1998

Semiautomated segmentation of ovarian follicular ultrasound images using a knowledge-based algorithm.

The application of a knowledge-based segmentation method to the problem of automatically detecting the outer follicle wall boundary in ultrasonographic images of ovaries is presented. A combination of computer detection and interactive adjustment was used to define an approximate inner follicle-wall boundary, which was then used by the computer algorithm as a priori knowledge to automatically find the outer follicle-wall border. The segmentation algorithm was tested on ultrasonographic images of women's ovaries that were imaged in vivo. The semiautomatic segmentations were compared to segmentations by an expert human observer in terms of border placement differences and in terms of quantitative parameters relevant to the physiologic status of the follicles. These physiological parameters include total and specific signal intensity from the follicle and from the follicle wall. The computer-detected outer follicle wall boundaries correlated well with the human observer-defined wall boundaries, in terms of enclosed follicle area, specific and total follicle signal, enclosed wall area, and specific and total wall signal. The actual border placement differences were also small, with a maximum placement difference of 1.47 +/- 0.83 mm and a root mean square (r.m.s.) placement difference of 0.59 +/- 0.28 mm.

Algorithms↗
PubMed1998

Intracardiac echocardiography: computerized detection of left ventricular borders.

A semi-automated method for two- and three-dimensional analysis of intracardiac echocardiography (ICE) images and image sequences is reported based on detection of epicardial and endocardial borders using graph searching. The border detection method was applied to 50 ICE images acquired in vivo in five dogs and to 108 images in 16 volumetric ICE image sequences from eight cadaveric pig hearts. The ICE images from the in vivo study showed good correlation between computer-detected and observer-defined left ventricular (LV) cavity areas and epicardial areas (r = 0.99, y = 0.98x + 0.43 [cm2]; r = 0.99, y = 0.98x + 1.11 [cm2]; respectively). In the cadaveric hearts, the LV volumes were determined with the volume measurement error of 7.6 +/- 7.7% and 11.3 +/- 11.2% for the aortic valve and mitral valve image sequences, respectively. Our method facilitates an accurate and computationally efficient approach for the quantitative assessment of ICE image data in 2D and 3D.

Animals↗
PubMed1998

[Percutaneous transfemoral arterial implantation of drug delivery system for arterial infusion therapy of advanced primary hepatic carcinoma].

OBJECTIVE: To study the efficiency of arterial infusion chemotherapy via drug delivery system (DDS) for advanced primary hepatic carcinoma. METHODS: Hepatic arterial infusion chemotherapy was performed in 82 cases of primary hepatic carcinoma with no indication for operation or transarterial embolism treatment. The patients were divided into 2 group as follows: (1) Group A: 42 patients were treated intra-arterially once every 1 or 2 weeks via implanted DDS. (2) Group B: 40 patients were treated through one bolus arterial infusion chemotherapy, once every month. RESULTS: The response rate (CR + PR) was 38.1% and 15.0% respectively in group A and B (P < 0.05); the 0.5-, 1- and 2- year survival rate was 61.9%, 28.6% and 9.5% respectively in group A, but 20%, 5%, 0% respectively in group B (P < 0.01); Liver, biliary, gastrointestinal and bone marrow toxicity in group A patients was greatly lower than those in group B patients. CONCLUSION: Intermittent arterial infusion chemotherapy via DDS significantly improves survival and quality of life in patients with advanced primary hepatic carcinoma.

Adult↗
PubMed1998

[Clinical application of combined acupuncture-drug anesthesia in cerebral functional area operation].

OBJECTIVE: To reach for higher tumor resection rate and low incidence of disability by operation with combined acupuncture-drug anesthesia in cerebral functional area. METHODS: According to the different operation ways, two groups of combination of body-acupuncture and ear-acupuncture were adopted. RESULTS: Satisfactory effect was obtained in all the 80 patients, including 20 cases in language center and 60 in sensory and motor center. The anesthesia grade 1 rate was 100%. After operation, no aggravation in dysphasia or dysfunction was found, 5 cases showed aggravation on myasthenia and dysesthesia, but all recovered within 2-4 weeks. CONCLUSION: Operation with combined acupuncture-drug anesthesia might result high tumor resection rate and low incidence of disability, therefore, this method of anesthesia could be regarded as one of the routine anesthesia methods.

Acupuncture Analgesia↗
PubMed1998

[Maxillary expansion with magnetic force: an animal experimental study].

Two adult rhesus monkeys were chosen for the experimental study of maxillary expansion with magnetic force. The duration of experiment was 70 days. The following methods were applied: 1. measuring the width between the two canines and the width between the two first molars on the casts, 2. taking occlusal radiographs for the observation of premaxillary and midpalatal sutures. 3. observing the histological sections under the microscope. The results showed the width of 3 to 3 and the width of 6 to 6 significantly increased, associating with the adaptation of periodontal tissues to the action of magnetic force.

Animals↗
PubMed1998

[Studies on the experimental transmission of Rattus-borne Hantavirus by Ornithonyssus bacoti].

AIM: To demonstrate the role of rat mite (Ornithonyssus bacoti) in the transmission of Rattus-borne hemorrhagic fever with renal syndrome (HFRS). METHODS: In the transmission experiments, about 100 O. bacoti per pool were isolated and placed in a jar, unfed for 4 d at 23 +/- 1 degrees C. Suckling Wistar rats inoculated with Hantavirus strain Z45 or Seoul virus strain UR were placed in each jar for free attack by the mites for 12 hours. After 14 d the normal suckling Wistar rats were bitten by the mites. Fifteen days later, the lung tissues and sera of the infected rats were collected and detected for Hantaviral antigen by indirect fluorescent antibody technique (IFAT). For demonstration of the infection of O. bacti with Rattus-borne Hantavirus PCR technique was applied to detect Rattus-borne Hantaviral RNA. RESULTS: Sukling Wistar rats inoculted Hantavirus strain Z45 or Seoul virus strain UR were bitten by O. bacoti and then these mites were fed on 4 and 5 of normal suckling rats in each jar, respectively. The antigens of Hantavirus strain Z45 were positive in all the lungs of the normal rats bitten by the mites, the sera titers of the rats were from 1:10 to 1:40. The antigens were positive in 3 of the 4 rats, the sera titers were from 1:20 to 1:40. Both of the viruses could be maintained in O. bacoti for 22 days. The blocking test showed when 1:30 Hantavirus immunosera were exposed to the lung samples and then reacted with the sera from the patients with HFRS, all the specific fluorescence reactions of the samples were blocked, whereas the control group including the normal rat lung tissues and sera were all negative (Fig. 1). CONCLUSION: O. bacoti might play a role as the vector of HFRS and a reservoir host as well.

Animals↗
PubMed1998

[Investigation of HGV infection in various populations in Guangxi].

In order to understand the situation of HGV infection in various populations in Liuzhou prefecture of Guangxi, Zhuangzu Autonomous Region, and also to compare the HGV, HBV, HCV infections between intravenous drug abusers and healthy persons (those for physical examination, the same below), the anti-HGV, -HCV and HBVM (HBsAg, HBsAb, HBeAg, HBeAb, HBcAb) were detected by ELA and, besides, tested further the 20 anti-HGV seropositive cases for HGV-RNA by RT-nPCR. The results showed that in the populations tested, the HGV seropositive rate was 9.8% (106/1079), separately they were 23.8% (5/21), 21.1% (23/109), 12.5% (6/48), 12.0% (6/50), 12.0% (20/166), 9.3% (3/32), 8.2% (34/413), 4.3% (6/140), and 3.0% (3/100) in liver cirrhosis, intravenous drug abusers, repeated blood and blood products transfused patients, hepatocellularcarcinoma patients, viral hepatitis, haemodialysis patients, healthy persons, paid blood donors and healthy pregnant women respectively. In intravenous drug abusers, the HGV, HBV, HCV infection rate were 21.2% (23/109), 75.3% (82/109) and 7.3% (8/109) respectively, while they were 8.2% (9/109), 20.1% (22/109), and 1.8% (2/109) in healthy persons respectively. These data showed that Liuzhou prefecture of Guangxi was HGV high epidemic area, HGV infection rate was higher in populations of intravenous drug abusers, viral hepatitis, liver cirrhosis and repeatedly blood and blood products transfused patients, even in pregnant women the HGV infection also occurred. There was a significant difference of HGV, HBV, HCV infection rates between intravenous drug abusers and healthy persons (P < 0.005).

Adult↗
PubMed1997

Antisense inhibition of silica-induced tumor necrosis factor in alveolar macrophages.

Tumor necrosis factor-alpha (TNFalpha) has been shown to play an important role in the pathogenesis of silicotic fibrosis. In this study, antisense oligonucleotides targeted to TNFalpha mRNA were used to inhibit silica-induced TNFalpha gene expression in alveolar macrophages. To achieve macrophage-specific oligonucleotide delivery, a molecular conjugate consisting of mannosylated polylysine that exploits endocytosis via the macrophage mannose receptor was used. Complexes were formed between the mannosylated polylysine and oligonucleotides and added to the cells in the presence of silica. Enzyme-linked immunoadsorbent assay showed that the complex consisting of the conjugate and antisense oligomer effectively inhibited TNFalpha production, whereas the oligomer alone had much less effect. Reverse transcriptase-polymerase chain reaction analysis revealed that the reduction in TNFalpha secretion was associated with specific ablation of targeted TNFalpha mRNA. The conjugate alone or conjugate complexed with inverted or sense sequence oligonucleotide had no effect. The promoting effect of the conjugate on antisense activity was shown to be due to enhanced cellular uptake of the oligomer via mannose receptor-mediated endocytosis. Cells lacking mannose receptors showed no susceptibility to the conjugate treatment. These results indicate that effective and selective inhibition of macrophage TNFalpha expression can be achieved using the antisense mannosylated polylysine system.

Animals↗
PubMed1997

Environmental and occupational determinants of blood pressure in rural communities in China.

PURPOSE: To identify and characterize major environmental and occupational determinants of blood pressure in rural communities in China. METHODS: In 1993 we conducted a large cross-sectional, community-based study of 20,216 residents aged 15 years or older, from the Yijing area of Anhui Province (8022 men, 12,194 women), one of whom were receiving treatment for hypertension. The mean systolic blood pressure was 116.7 +/- 19.5 mmHg for men and 113.2 +/- 19.4 mmHg for women. RESULTS: The mean diastolic blood pressure was 72.4 +/- 12.1 mmHg for men and 70.4 +/- 11.6 mmHg for women. Age and body mass index were the two most important determinants of blood pressure in this population. With controls for age and body mass index, height and weight remained significant predictors of blood pressure. Multiple linear regression analysis indicated that alcohol consumption, self-reported exposure to noise, drinking of tap water and pond water, occupational exposure to dust/fumes/gases, rice consumption, inferior housing, household crowdedness, and being unmarried were related to increased blood pressure levels. Vegetable intake, frequent consumption of meat at meals, high level of physical activity, exposure to straw-combustion smoke, and pesticide use were negatively associated with blood pressure. CONCLUSIONS: Our study demonstrated that a broad array of demographic, ergonomic, nutritional, and environmental factors are critical determinants of blood pressure in this rural Chinese population.

Adolescent↗