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C Jiang

Publications and source records attributed to C Jiang.

At least 109 records · Page 6Linked to original sources
PubMed1999

Fractal-based image texture analysis of trabecular bone architecture.

Fractal-based image analysis methods are investigated to extract textural features related to the anisotropic structure of trabecular bone from the X-ray images of cubic bone specimens. Three methods are used to quantify image textural features: power spectrum, Minkowski dimension and mean intercept length. The global fractal dimension is used to describe the overall roughness of the image texture. The anisotropic features formed by the trabeculae are characterised by a fabric ellipse, whose orientation and eccentricity reflect the textural anisotropy of the image. Tests of these methods with synthetic images of known fractal dimension show that the Minkowski dimension provides a more accurate and consistent estimation of global fractal dimension. Tests on bone x-ray (eccentricity range 0.25-0.80) images indicate that the Minkowski dimension is more sensitive to the changes in textural orientation. The results suggest that the Minkowski dimension is a better measure for characterising trabecular bone anisotropy in the x-ray images of thick specimens.

Animals↗
PubMed1999

Effects of L-tetrahydropalmatine on energy metabolism, endothelin-1 and NO during acute cerebral ischemia-reperfusion of rats.

To investigate the effects of L-tetrahydropalmatine (L-THP) on energy metabolism, endothelin-1 (ET-1) and NO during acute cerebral ischemia-reperfusion of rats, 24 Wistar rats were randomly divided into four groups, with 6 rats in each group: sham-operation group, simple ischemia group, ischemia-reperfusion group and treatment group (L-THP group). Cerebral ATP, lactate, ET-1 and NO levels were measured in all groups. Our results showed that treatment with L-THP could increase cerebral ATP levels, but decrease cerebral lactate, ET-1 and NO concentrations during ischemia-reperfusion in the treatment group. It is concluded that L-THP could improve cerebral energy metabolism and protect the injured brain tissue, the mechanism of which might be related to suppression of overproduction of ET-1 and NO.

Animals↗
PubMed1999

Evaluation of two string tests for obtaining gastric juice for culture, nested-PCR detection, and combined single- and double-stranded conformational polymorphism discrimination of Helicobacter pylori.

We have compared two gastric string tests for obtaining gastric juice for culture of Helicobacter pylori and for nested-PCR detection and PCR-based combined single- and double-stranded conformational polymorphism (SDSCP) discrimination of infecting strains. String test specimens were obtained from one seropositive volunteer for 13 consecutive weeks. The distal 10 cm of each string was suspended in 1 ml saline and quantitatively cultured. An additional nine volunteers with histories of upper-gastrointestinal complaints were given a string test for culture and nested-PCR assay. H. pylori isolates and/or gastric juice from each volunteer were extracted for DNA and analyzed by PCR-based SDSCP. Quantitative culture showed that the Entero-test was four times as sensitive as the Gastro-test but was more prone to contamination by oral flora. However, the two string tests are equally sensitive by PCR assays. Thus, the Gastro-test is more suitable for culture detection of H. pylori, since it is less prone to oral contamination and its shorter length is better tolerated. SDSCP analysis of H. pylori DNA from four PCR-positive volunteers without requiring culture showed four distinct profiles, indicating different infecting strains. SDSCP analysis of strains isolated before and after treatment of one volunteer had the same SDSCP profile, suggesting endogenous reinfection by the same strain.

Female↗
PubMed1999

The structure of the nucleosome core particle of chromatin in chicken erythrocytes visualized by using atomic force microscopy.

The structure of the nucleosome core particle of chromatin in chicken erythrocytes has been examined by using AFM. The 146 bp of DNA wrapped twice around the core histone octamer are clearly visualized. Both the ends of entry/exit of linker DNA are also demonstrated. The dimension of the nucleosome core particles is approximately 1-4 nm in height and approximately 13-22 nm in width. In addition, superbeads (width of approximately 48-57 nm, height of approximately 2-3 nm) are occasionally revealed, two turns of DNA around the core particles are also detected.

Animals↗
PubMed1999

Characterization of bone quality using computer-extracted radiographic features.

Both bone mineral density (BMD) and trabecular structure are important determinates of bone mechanical properties. However, neither BMD or trabecular structural features can completely explain the variations in bone mechanical properties. In this study, we combine BMD and bone structural features to characterize bone mechanical behavior. Radiographs were obtained from 34 femoral neck specimens excised during total hip arthroplasties. Each neck radiograph was digitized and a region of interest (ROI) was selected from the medial side of the femoral neck. Textural features, the global Minkoswski dimension and trabecular orientation, were extracted from each ROI image using Minkowski dimension analysis. The BMD of each specimen was measured using dual-energy x-ray absorptiometry (DXA) and subsequently normalized by bone size as measured from a standard pelvis radiograph. Mechanical testing was performed on the trabecular bone cubes machined from each femoral neck to yield bone mechanical properties. Multiple regression was performed to select the best features to predict bone mechanical properties. The results suggest that, using multiple predictors including normalized BMD structural features, and patient age, the coefficients of determination (R2) improved over the use of BMD alone. For bone strength, the R2 was improved from 0.24 using conventional BMD to 0.48 using a four-predictor model. Similar results were obtained in the prediction of Young's modulus, i.e., the R2 was improved from 0.25 to 0.55 in going from the model using conventional BMD to a four-predictor model. This study demonstrates the contributions of normalized BMD, structural features, and age to bone mechanical properties, and suggests a potential method for the noninvasive evaluation of bone mechanical properties.

Absorptiometry, Photon↗
PubMed1999

Computerized radiographic texture measures for characterizing bone strength: a simulated clinical setup using femoral neck specimens.

We are investigating computerized methods to ultimately characterize bone trabecular pattern from clinical skeletal radiographs. In this paper, we present a "phantom" for potential use in the development and evaluation of computerized methods for characterizing radiographic trabecular patterns and ultimately bone strength. Femoral neck specimens were excised during total hip arthroplasties from subjects exhibiting a range of diseases. To mimic the femoral neck in vivo, a "simulated clinical" setup was implemented in which specimens were exposed under conditions that yielded radiographs similar in appearance to standard pelvis radiographs. Fourier-based and fractal-based texture measures were used in the computer analysis; including RMS variation, first moment of the power spectrum, angular-dependent forms of these measures, and fractal dimension. The texture measures obtained from the "simulated clinical" specimen films correlated modestly with those from direct exposure "verification" films of the specimens (r= 0.59-0.69; p<0.0001). From our study, we conclude that the femoral neck specimen "phantoms" may be useful in the development and evaluation of computerized methods for analyzing bone trabecular patterns from skeletal radiographs. The use of a phantom that simulates the clinical radiographic examination allows for repeat exposures without the concern of excessive radiation exposure to a patient.

Adult↗
PubMed1999

Coadministration of interleukin 12 expression vector with antigen 2 cDNA enhances induction of protective immunity against Coccidioides immitis.

Interleukin 12 (IL-12) plays an important role in the induction of protective immunity against cancer and infectious diseases. In this study we asked whether IL-12 cDNA could increase the protective capacity of the antigen 2 (Ag2) gene vaccine in experimental coccidioidomycosis. Coimmunization of BALB/c mice with a single-chain IL-12 cDNA (p40-L-p35) and Ag2 cDNA, both subcloned into the pVR1012 plasmid, significantly enhanced protection against systemic challenge with 2,500 arthroconidia, as evidenced by a greater-than-1.3-log-unit reduction in the fungal load in the lungs and spleens compared to mice receiving the pVR1012 vector alone, Ag2 cDNA alone, or IL-12 cDNA alone. The enhanced protection was associated with increased gamma interferon secretion; production of immunoglobulin G2a (IgG2a), IgG2b, and IgG3 antibodies to Coccidioides immitis antigen; and the influx of CD4(+) and CD8(+) T cells in lungs and spleens. When challenged by the pulmonary route, mice covaccinated with Ag2 cDNA and IL-12 cDNA were not protected at the lung level but did show a significant reduction in the fungal load in their livers and spleens compared to mice vaccinated with Ag2 cDNA or IL-12 cDNA alone. These results suggest that IL-12 acts as a therapeutic adjuvant to enhance Ag2 cDNA-induced protective immunity against experimental coccidioidomycosis through the induction of Th1-associated immune responses.

Animals↗
PubMed1999

Genetic vaccination against Coccidioides immitis: comparison of vaccine efficacy of recombinant antigen 2 and antigen 2 cDNA.

Previous studies from our laboratory established that C-ASWS, an alkali-soluble, water-soluble extract from cell walls of Coccidioides immitis, protects mice against lethal challenge with this fungus. The C-ASWS extract contains a glycosylated protein, designated antigen 2 (Ag2), and a polysaccharide antigen. We recently cloned Ag2 cDNA and showed that the recombinant fusion protein elicited strong delayed-type hypersensitivity responses in immunized mice. This investigation was undertaken to determine if the recombinant Ag2 protein, expressed as an Ag2-glutathione S-transferase (GST) fusion protein, or Ag2 cDNA would protect mice against lethal challenge with C. immitis. The recombinant Ag2-GST protein protected BALB/c mice against intraperitoneal challenge with 250 arthroconidia, as assessed by a decrease in fungal CFU in tissues. The Ag2-GST-immunized mice did not show, however, an increased survival during a 30-day period postinfection. By contrast, immunization of mice with Ag2 cDNA ligated into the pVR1012 plasmid engendered protection against intraperitoneal challenge with 2,500 arthroconidia and against pulmonary challenge with 50 arthroconidia. Vaccine efficacy paralleled the development of delayed-type hypersensitivity responses to C. immitis antigen. Whereas mice vaccinated with the recombinant Ag2-GST protein did not mount footpad hypersensitivity to C-ASWS or the recombinant Ag2-GST protein, mice vaccinated with the pVR1012-Ag2 construct mounted a strong footpad hypersensitivity and their spleen cells secreted gamma interferon upon in vitro stimulation with the Ag2-containing C-ASWS extract. This is the first investigation to show that genetic immunization can protect against lethal challenge with C. immitis.

Animals↗
PubMed1999

Construction of a single-chain interleukin-12-expressing retroviral vector and its application in cytokine gene therapy against experimental coccidioidomycosis.

T-cell-mediated immunity is an important determinant in protection against primary infection with Coccidioides immitis, a dimorphic fungal pathogen that causes the disease coccidioidomycosis. To determine if interleukin-12 (IL-12) gene therapy could potentiate host response against C. immitis, we constructed a single-chain cDNA encoding the p40 and p35 subunits linked by a polylinker and, using a retroviral vector, transfected J774 macrophages with the construct. The transduced J774 cells expressed IL-12 in vitro, with a mean concentration of 28,440 pg from 10(6) cells in 48 h as measured by an IL-12 (p75)-specific enzyme-linked immunosorbent assay. The secreted IL-12 was biologically active, as judged by its ability to induce the production of gamma interferon (IFN-gamma) by spleen cells from BALB/c mice. Treatment of the highly susceptible BALB/c mouse strain with the IL-12-transduced J774 cells inhibited C. immitis growth in tissues from mice challenged by a pulmonary route, as evidenced by 1.37-, 2.59-, and 1.22-log reductions in the number of CFU in the lungs, spleens, and livers, respectively, compared to the fungal load in mice given vector-transduced J774 cells. The protective effect of IL-12 gene therapy was accompanied by increased levels of IFN-gamma in the lungs and sera of mice treated with IL-12-transduced J774 cells and the constitutive production of IFN-gamma by their spleen cells cultured in vitro. These results suggest that IL-12 gene therapy could be used as adjunct therapy for coccidioidomycosis.

3T3 Cells↗
PubMed1999

Restoration of cyclic adenosine monophosphate-stimulated chloride channel activity in human cystic fibrosis tracheobronchial submucosal gland cells by adenovirus-mediated and cationic lipid-mediated gene transfer.

In human airways, the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) is predominantly expressed in serous cells of the tracheobronchial glands. Despite considerable evidence that submucosal glands are important contributors to the pathophysiology of CF lung disease, most attempts at CFTR gene transfer have primarily targeted airway surface epithelial cells. In this study, we systematically evaluated CFTR gene transfer into cultures of immortalized CF human tracheobronchial submucosal gland (6CFSMEO) cells using adenovirus and cationic lipid vectors. We found that the efficiency of adenovirus-mediated gene transfer was comparable in 6CFSMEO and CFT1 cells (a surface airway epithelial cell line isolated from a subject with CF). So was the ranking order of adenovirus vectors containing different enhancers/promoters (CMV >> E1a approximately phosphoglycerokinase), as determined by both X-Gal staining and quantitative measurement of beta-galactosidase activity. Further, we provide the first demonstration that cationic lipids mediate efficient gene transfer into 6CFSMEO cells in vitro. The transfection efficiency at optimal conditions was higher in 6CFSMEO than in CFT1 cells. Finally, either infection with adenoviral vectors or transfection with cationic lipid:plasmid DNA complexes encoding CFTR significantly increased chloride (Cl-) permeability, as assessed using the 6-methoxy-N-(3-sulfopropyl)-quinolinium (SPQ) fluorescence assay, indicating restoration of functional CFTR Cl- channel activity. These data show that although the mechanisms of transfection may be different between the two cell types, 6CFSMEO cells are as susceptible as CFT1 cells to transfection by adenoviral and cationic-lipid gene transfer vectors.

Adenoviridae↗
PubMed1999

Studies on risk of leprosy relapses in China: relapses after treatment with dapsone monotherapy.

Based upon the data from the Chinese National System for Leprosy Surveillance, this paper reports on the relapses in 297,343 leprosy patients [multibacillary (MB) 106,518, paucibacillary (PB) 190,825] cured by dapsone monotherapy. A total of 11,055 (MB 8675, PB 2380) patients relapsed during an accumulated follow-up period of 4,229,050 patient-years (PY), giving an overall relapse rate of 3.72 per 100 cases or 2.61 per 1000 PY, i.e., 8.14% or 5.91 per 1000 PY over an average follow-up period of 13.8 +/- 8.4 years in MB patients and 1.25% or 0.86 per 1000 PY over an average period of 14.5 +/- 8.9 years in PB patients. For either the overall relapse rate per 100 cases or per 1000 PY, the differences between MB and PB patients were statistically significant, except during 36-40 years of follow up. For both MB and PB patients, the relapse rates showed consistently significant decreases year by year, particularly in PB patients whose relapse rate per 1000 PY was 1.21 in year 10 of follow up; whereas it remained more than 10 per 1000 PY in MB patients. In view of that, the overall relapse rates in MB and PB patients cured by dapsone monotherapy were acceptably low, and most of these patients have been followed up for more than a mean incubation period of observed dapsone relapse. Along with the further extension of follow up, the risk of relapse in dapsone-cured patients will not be expected to increase. This conclusion should be considered when planning policy for the management of patients released from dapsone monotherapy.

China↗
PubMed1999

Studies on risk of leprosy relapses in China: relapses after treatment with multidrug therapy.

Based upon the data from the Chinese National System for Leprosy Surveillance, this paper reports on the relapses in 47,276 leprosy patients cured by or released from WHO-recommended multidrug therapy (WHO/MDT). The overall relapse rate was 0.73/1000 patient-years (PY). There was a statistically significant difference in the relapse rates of WHO/MDT-MB (0.61/1000 PY) and WHO/MDT-PB (1.04/1000 PY) (chi 2 = 15.7, p < 0.01) patients. For multibacillary (MB) patients, the relapse rate in patients treated with fixed-duration MDT (0.56/1000 PY) was comparable with that in patients treated with MDT until skin-smear negativity (0.73/1000 PY) (chi 2 = 2.20, p > 0.05). Our present study suggests that fixed-duration MDT is a cost-effective regimen for the treatment of leprosy in China. The present results also show that relapse of leprosy is acceptably low and has not yet become a serious clinical or public health problem but, based upon the incubation of relapse in MDT patients, it is necessary to encourage annual follow up for at least 5 years for paucibacillary (PB) and 10 years for MB patients after being released from WHO/MDT.

China↗
PubMed1999

Endovascular embolization of traumatic carotid cavernous fistulas.

OBJECTIVE: To analyze the effectiveness of endovascular embolization on treatment of traumatic carotid-cavernous fistula (TCCF). METHODS: From 1986 to 1997, 482 cases of traumatic carotid-cavernous fistula were treated by endovascular embolization in the Beijing Neurosurgical Institute. Several kinds of balloon-catheter were used for embolization. External carotid-cavernous fistulas and rare carotid-cavernous fistulas (CCF) with minute leakage were treated by cyanoacrylate or coils. Although artery approach was applied in most cases (477 cases), vein approach showed its own advantages in some special cases. RESULTS: We found a special "bileakage sign" indicating multileakage of TCCF, which was never mentioned before. All 482 cases were embolized successfully, and 405 cases maintained the patency of internal carotid artery (ICA). No treatment-related deaths occurred and the symptoms and signs of 462 cases were relieved after embolization. Emergency embolization was needed in some conditions such as serious epistaxis, delayed or repeated subdural hematoma, and rapid visual impairment. CONCLUSION: Endovascular embolization of TCCF is a safe and efficient method. Carefully selected operation time, operative approach, and materials are the essential factors to reach a best result.

Accidents, Traffic↗
PubMed1999

[Expression and stability of fragment of Plasmodium merozoite major surface protein 1 in recombinant attenuated Salmonella typhimurium].

OBJECTIVE: To determine the invasive ability of recombinant attenuated Salmonella typhimurium X4064 (pQEM1) strain containing gene fragment of Plasmodium falciparium merozoite surface protein 1 (MSP1), the stability of its plasmid, and its re-expression. METHODS: BALB/c mice were fed with recombinant attenuated S. typhimurium containing No. 1 gene fragment of P. falciparium MSP1 by gastric tube. Plate incubation, plasmid endonuclease analysis and Western blot were used to identify the recombinant attenuated S. typhimurium strains isolated from mice and the ability of re-expression, and its growth were determined in vitro. RESULTS: The attenuated strain X4064 of S. typhimurium isolated from mice contained recombinant plasmid pQEM1, no. 1 MSP1 fragment of P. falciparium was expressed in vitro in S. typhimurium X4064 (pQEM1) strain, and its growth curve of X4064 (pQEM1) strain in mice was basically similar to that of X4064. CONCLUSION: The recombinant plasmid pQEM1 could steadily exist in the X4064 strain of S. typhimurium, without influence on its invasion into host cells. X4060 (pQEM1) strain isolated from infected mice still had the ability to re-express M1 protein.

Animals↗
PubMed1998

The C fibre reflex of the cat urinary bladder.

1. Reflexes evoked in bladder parasympathetic neurones by electrical stimulation of bladder C afferent fibres were studied in cats anaesthetized with alpha-chloralose. The responses were compared with the ordinary micturition reflex evoked by low-threshold Adelta afferents from bladder mechanoreceptors and mediated by a spino-ponto-spinal reflex pathway. 2. The bladder was catheterized for fluid instillations and pressure recordings. Efferent reflex discharges were recorded from the cut central end of a small distal bladder branch of the pelvic nerve. The remaining bladder pelvic nerve branches were stimulated electrically close to the bladder. 3. Stimulation at C afferent intensity evoked a late reflex discharge in bladder pelvic efferents in all animals. The response was centrally mediated, had a latency of 150-250 ms, and was much weaker after stimulation on the contralateral nerve. 4. The bladder C fibre reflex differed in several functional aspects from the ordinary Adelta micturition reflex. It could be evoked at a low rate of stimulation, with an empty bladder and no background activity from bladder mechanoreceptors. In this situation, the normal Adelta micturition reflex is not elicited. The C fibre reflex also survived an acute spinalization at a low thoracic level. 5. The C fibre reflex was strongly inhibited by dorsal clitoris or dorsal penis nerve stimulation, an effect that was maintained after spinalization. It was facilitated by bladder or urethra exposure to cold and menthol, stimuli that activate specific cold-sensitive receptors associated with unmyelinated C afferents. 6. It is concluded that the central pathway of the C fibre reflex is spinal and partly separate from that of the ordinary micturition reflex. These observations are in keeping with the clinical finding that a bladder cooling reflex can be elicited in patients with disturbed descending control of the bladder.

Animals↗
PubMed1998

Efficiency of cationic lipid-mediated transfection of polarized and differentiated airway epithelial cells in vitro and in vivo.

Systematic analysis of a large number of different cationic lipids has led to the identification of novel structures (GL-67) and formulations of cationic lipid:plasmid DNA (pDNA) complexes that facilitate high levels of gene expression in lungs of mice. However, despite significant improvement in gene transfer activity, we show here that the efficiency of GL-67-mediated gene transduction of intact airway epithelia is still relatively low. Administration of GL-67:pCF1-CFTR (encoding the cystic fibrosis transmembrane conductance regulator) complexes into the nasal epithelium of cystic fibrosis (CF) transgenic mice resulted only in marginal correction of the ion transport defects. Measurements of nasal potential differences (PD) showed no correction of the sodium (Na+) transport defect, and only partial restitution of the chloride (Cl-) transport defect was achieved in a small proportion of the animals after perfusion of the nasal epithelium with the complexes. Furthermore, in contrast to results obtained following instillation of GL-67:pDNA complexes into the lungs of mice, perfusion of GL-67:pDNA into the nasal epithelium resulted only in a moderate enhancement of gene transduction activity relative to that attained with naked pDNA alone. To determine the basis for this low efficiency of transfection, a series of studies was conducted to identify some of the barriers governing cationic lipid-mediated gene transfer to the airway epithelium. We show here that the transfection activity of GL-67 was affected by the polarization, differentiation, and proliferative state of the cells. Diminished transfection activity was observed with nonmitotic, highly polarized and differentiated airway epithelial cells. This observed reduction in gene expression with nonmitotic cells was determined to be due in part to inefficient nuclear translocation of the pDNA from the cytoplasm. Together these data indicate that much improvement in the ability of cationic lipids to transfect polarized and differentiated airway epithelial cells is a necessary prerequisite for effective cationic lipid-mediated gene therapy of airway diseases such as CF.

Animals↗
PubMed1998

Objective evaluation of fatigue by event-related potentials.

The purpose of this study was to assess the relationship between mental fatigue and event-related potentials (ERPs). Six healthy men (mean age: 22 years old) performed a simple calculation for 6 h. Auditory ERPs were recorded before and after the calculating task. The scores of subjective fatigue symptoms were significantly increased, and P300 latency of auditory ERPs was significantly prolonged by the calculating task (P<0.05). We suggest that the recording of ERPs may be useful for the objective evaluation of mental fatigue.

Adult↗