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Biomedical subjects

M Shi

Publications and source records attributed to M Shi.

At least 73 records · Page 4Linked to original sources
PubMed1998

Systemic effect of human growth hormone after intramuscular injection of a single dose of a muscle-specific gene medicine.

A muscle-specific gene medicine is described that provides for long-term secretion of biologically active human growth hormone (hGH) from skeletal muscle into the systemic circulation. The hGH gene medicine is composed of a muscle-specific hGH plasmid expression system complexed with a protective, interactive, non-condensing (PINC) delivery system. The muscle-specific gene expression system, pSK-hGH-GH, was constructed by linking the promoter/enhancer regions of chicken skeletal alpha-actin to hGH gene. C2C12 myoblast transfection with pSK-hGH-GH resulted in the synthesis of hGH in a muscle-specific manner. Direct injection into rat tibialis cranialis muscle of pSK-hGH-GH complexed with a polymeric PINC delivery system, polyvinylpyrrolidone (PVP), produced hGH levels in muscle that were 10- to 15-fold higher compared with plasmid formulated in saline at 14 days post-injection. Intratracheal instillation in rat lung of pSK-hGH-GH did not produce significantly detectable levels of hGH. In hypophysectomized rats, a single intramuscular dose of the pSK-hGH-GH/PVP complex resulted in hGH expression and a subsequent increase in serum levels of rat IGF-I and growth. hGH expression and effects on rat serum IGF-I levels were detectable up to 28 days after injection of formulated plasmid and effects on growth were detectable unto 21 days. Anti-hGH antibodies were detectable in serum at 14 days post-injection, reached a plateau at 21 days, and remained elevated through the study period. Cyclosporin treatment of the pSK-hGH-GH/PVP-injected animals completely inhibited the antibody response and resulted in increased hGH expression.

Actins↗
PubMed1998

Spontaneous and Fas-mediated apoptosis are diminished in umbilical cord blood neutrophils compared with adult neutrophils.

Apoptosis mediates neutrophil (PMN) phagocytosis and is influenced by cytokines and the Fas/Fas ligand pathway. To determine whether apoptosis of cord blood PMN differs from those of adults, cultured PMN were evaluated by morphological analysis, flow cytometry (TUNEL assay), and DNA gel electrophoresis. In addition, we studied the effect of anti-Fas IgM or cycloheximide on induction of PMN apoptosis. Spontaneous apoptosis (24 h) was less in cord blood PMN (mean +/- SD; 29 +/- 9 vs. adults, 56 +/- 14%, P < 0.001). Treatment (6 h) with anti-Fas IgM induced less apoptosis in cord blood PMN (24 +/- 6 vs. adults, 63 +/- 7%, P < 0.001), as did treatment with cycloheximide (13 +/- 10 vs. adults, 55 +/- 16%, P < 0.01). These data suggest the pre-existence of proteins that inhibit apoptosis or the absence of those that promote apoptosis in cord blood PMN.

Adult↗
PubMed1998

A physicochemical approach for predicting the effectiveness of peptide-based gene delivery systems for use in plasmid-based gene therapy.

Novel synthetic peptides, based on carrier peptide analogs (YKAKnWK) and an amphipathic peptide (GLFEALLELLESLWELLLEA), have been formulated with DNA plasmids to create peptide-based gene delivery systems. The carrier peptides are used to condense plasmids into nanoparticles with a hydrodynamic diameter (DH) ranging from 40 to 200 nm, which are sterically stable for over 100 h. Size and morphology of the carrier peptide/plasmid complex have been determined by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM), respectively. The amphipathic peptide is used as a pH-sensitive lytic agent to facilitate release of the plasmid from endosomes after endocytosis of the peptide/plasmid complex. Hemolysis assays have shown that the amphipathic peptide destabilizes lipid bilayers at low pH, mimicking the properties of viral fusogenic peptides. However, circular dichroism studies show that unlike the viral fusion peptides, this amphipathic peptide loses some of its alpha-helical structure at low pH in the presence of liposomes. The peptide-based gene delivery systems were tested for transfection efficiency in a variety of cell lines, including 14-day C2C12 mouse myotubes, using gene expression systems containing the beta-galactosidase reporter gene. Transfection data demonstrate a correlation between in vitro transfection efficiency and the combination of several physical properties of the peptide/plasmid complexes, including 1) DNA dose, 2) the zeta potential of the particle, 3) the requirement of both lytic and carrier peptides, and 4) the number of lysine residues associated with the carrier peptide. Transfection data on 14-day C2C12 myotubes utilizing the therapeutic human growth hormone gene formulated in an optimal peptide gene delivery system show an increase in gene expression over time, with a maximum in protein levels at 96 h (approximately 18 ng/ml).

Amino Acid Sequence↗
PubMed1998

Diagnosis and classification of hepatic echinococcosis by ultrasonography.

OBJECTIVE: To make an early and correct diagnosis of hepatic echinococcosis. METHODS: A total of 1092 patients with hepatic echinococcosis underwent operation in our hospital between 1984 and 1995. Of these patients, 427 (39.1%) were cases with complications, including secondary infection, rupture, obstructive jaundice, anaphylactic shock, disseminated implantation with resultant multiple echinococcosis and portal hypertension. The ultrasonic examination has been generally used in clinical practice for comprehensive evaluation which can dectedct the preoperative diagnostic accuracy rate. RESULTS: B-mode ultrasonography can be used not only to detect the location, dimension and pathological characteristics of hydatid cyst but also to show the pathological changes of various complications caused by echinococcosis. Seven patterns specific ultrasonic scanning images were revealed. In this series the diagnostic accuracy rate reached 98.8%. CONCLUSIONS: Ultrasonic examination is harmless to human body, and has been widely used in combination with immunological tests in clinical and epidemiological studies to detect the asymptomatic parasite carriers in early stage and to improve the preoperative diagnostic accuracy rate.

Echinococcosis, Hepatic↗
PubMed1998

[Two-phase dynamic CT and trans-abdominal ultrasonography for preoperative TNM staging of gastric carcinoma: a correlation study with surgery and pathology].

OBJECTIVE: To assess the value of two-phase dynamic CT and transabdominal ultrasonography in the preoperative staging of gastric carcinoma. METHODS: Two-phase dynamic CT was performed in 63 cases of gastric carcinoma confirmed histologically by fibro-gastroscopic biopsy. Of the 63 cases, 20 had trans-abdominal ultrasonography (US) immediately after CT examination. Imaging findings were correlated with surgical and pathologic findings. RESULTS: For evaluation of T and N staging, the accuracy of dynamic CT was 53.23% and 58%, respectively, that of CT in combination with US for T staging was 70%, which was statistically different from that of CT alone (P < 0.05). Accuracy of CT in combination with US for TNM staging was 90%, there was marked statistical difference (P < 0.05) compared with the accuracy of US. CONCLUSION: The major role of dynamic CT in combination with trans-abdominal ultrasonography for staging of gastric carcinoma is to ascertain whether the tumor has invaded adjacent structures-T staging, which is helpful in treatment planning.

Adolescent↗
PubMed1998

[Correlation study of high-resolution CT with pathologic finding of solitary small lung nodules].

OBJECTIVE: To correlate high resolution CT(HRCT) with pathologic findings and to evaluate the capability of HRCT versus conventional CT(CCT) to provide informations for accurate diagnosis of solitary small lung nodules. METHODS: Seventy-three cases (75 nodules) of solitary lesions in the lung less than 3 cm in diameter were examined with HRCT (64 cases had CCT) before surgery and correlated with histo-pathologic findings. RESULTS: In the 37 proven carcinoma, on HRCT, the lesions were round and oval in shape (34), deeply lobulated(28), with serrated margin(33), thin spiculation(37), air alveologram(19), and air bronchogram (10). Histologically, the tumor showed irregular growth pattern with interstitial fibrous proliferation and intra-tumoral residual air-containing spaces in alveoli and bronchioles. Intratumoral fat or calcification, satellate lesions, thick or long spicules, moderate or marked pleural adhesions, scallop-shaped contour were the common findings of benign lesions. HRCT was significantly superior to CCT in the assessment of the intra-structure, contour and margin of the lesion. CONCLUSION: HRCT is recommended routinely for the evaluation of solitary small pulmonary nodules.

Adenocarcinoma↗
PubMed1998

[Two-phase dynamic CT findings of gastric carcinoma and its value for tumor detection and gross classification].

OBJECTIVE: To analyze the two-phase dynamic CT features of gastric carcinoma and to assess its usefulness for tumor detection and gross classification. METHODS: Two-phase dynamic CT was performed in 63 cases of gastric carcinoma proved histologically by fibro-gastroscopic biopsy. CT features of gastric carcinoma, tumor detection, and gross classification were correlated with surgical and pathologic findings. RESULTS: The detectability by two-phase enhanced CT scanning of early and advanced gastric carcinoma was 100% and 98.2%, respectively. The overall accuracy of gross classification for advanced carcinoma was 65.4%, but for early gastric carcinoma, it was 0. The accuracy of Borrmann type II, III, IV was 85.7%, 100%, 55.6%, respectively. In the first phase (early enhancing phase) CT scan, the manifestation of early gastric carcinoma included local thickening of gastric wall, moderate or marked heterogeneous enhancement of lesions in 4 cases and mild enhancement in the other 4 cases. Local or extensive thickening of gastric wall, with or without ulceration, moderate or marked heterogeneous enhancement in early enhancing phase were shown in advanced gastric carcinoma. In the second phase, the degree of tumor enhancement in advanced carcinoma was slightly higher than that of the normal part of gastric wall. There were 4 cases with mucinous adenocarcinoma, a target or laminary appearance was present in 3 cases, and intramural calcification was present in 2 cases. CONCLUSION: 1. Enhanced dynamic CT scan plays a significant role in the diagnosis of gastric carcinoma, early enhancing phase scanning is the technique of choice nowadays for demonstrating tumor lesions. 2. Sophisticated scanning technique is mandatory in improving the diagnostic accuracy of gastric carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1998

[Cervical lymph node metastasis: CT, ultrasound versus physical palpation].

OBJECTIVE: To evaluate the accuracy of CT, ultrasonography and manual palpation in the diagnosis of cervical lymph node metastasis and to identify the value of CT and ultrasound in the diagnosis of occult cervical lymph node metastasis. METHODS: Sixty patients (74 sides) were studied double-blindedly by CT and ultrasonography prior to cervical lymphadenectomy, and the results were correlated with histo-pathologic findings. RESULTS: According to histologic examination of the dissected specimens, in 56 of 74 sides there were cervical lymph node metastases, 46 of the 56 sides with metastatic nodes were diagnosed by manual palpation(sensitivity, 82.1%; specificity, 83.3%; accuracy, 82.4%). However, lymphnode metastases in 53 sides were revealed by CT(sensitivity, 94.6%; specificity, 94.4%; accuracy, 94.6%), i.e., CT discovered 70% of the occult metastatic nodes in this series. Lymph node metastases were diagnosed accurately in 51 sides by ultrasonography (sensitivity, 91.1%; specificity, 94.4%; accuracy, 91.9%), and 50% of the occult metastatic nodes were found by ultrasound. CONCLUSION: CT, ultrasound examinations are superior to physical palpation in ascertaining cervical lymph node metastasis, as 50%-70% of the occult cervical metastatic nodes can be diagnosed.

Adolescent↗
PubMed1997

Comparison of bicoid-dependent regulation of hunchback between Musca domestica and Drosophila melanogaster.

Co-evolution between developmental regulatory elements is an important mechanism of evolution. This work compares the hunchback-bicoid interaction in the housefly Musca domestica with Drosophila melanogaster. The Musca HUNCHBACK protein is 66% conserved and partially rescues a hunchback mutant, yet the BICOID-dependent promoter (P2) of Musca hunchback is unexpectedly diverged from D. melanogaster. Introduced into D. melanogaster, this promoter drives a normal P2 pattern during the syncytial blastoderm stage but is expressed ectopically at the anterior pole of the embryo at later stages. We also report differences in the early expression of hunchback in Musca. We suggest that conservation of the morphogenetic function of bicoid in different sized embryos of higher diptera requires co-evolution of bicoid and its target binding sites.

Amino Acid Sequence↗
PubMed1997

Early levels of CD4, neopterin, and beta 2-microglobulin indicate future disease progression.

Reduced CD4 T cell level and increased serum neopterin and beta 2-microglobulin levels, which reflect immunological activation and dysregulation, are three important markers of HIV disease. The aim in this study is to delineate more clearly the relation of activation to future CD4 values and disease progression. By analyzing a cohort of 198 seroconverters from the Multicenter AIDS Cohort Study with 9 years' follow-up, the dynamic changes and levels of these three markers and their interrelationships are explored. We observed that the levels of markers in the first year after seroconversion have a much stronger impact on the progression of the disease than the preseroconversion marker levels. The actual change during the year after seroconversion is not as important as the final level reached during that year. The early levels of markers after seroconversion appear to be good indicators of the subsequent course of disease as defined by CD4 level and slightly better than the quantitative changes following seroconversion or the changes in the period 1 to 2.5 years after seroconversion. To investigate the variation between subjects, the 198 seroconverters were stratified into three approximately equal-sized groups in 12 ways based on their pre- and postseroconversion levels and changes in the three markers. The group with the highest CD4 level within a year after seroconversion maintains the highest CD4 level 8 years after seroconversion. The group with the lowest level of neopterin or beta 2-microglobulin in this period has much higher future CD4 counts than the other two groups. The level of markers during the first year after seroconversion has a high predictive power for AIDS onset. Substantial differences in the hazards of AIDS are found between the groups with the highest and lowest CD4 count, neopterin, and beta 2-microglobulin following seroconversion. The three markers are generally correlated throughout the postseroconversion period but can provide distinct information. High current levels of neopterin or beta 2-microglobulin tend to be associated with low future CD4 count, while current levels of CD4 count have less association with future neopterin and beta 2-microglobulin levels.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Studies on growth-promoting action of insulin: mitogenic activity of insulin and its analogues in mouse mammary tumor cells.

Growth-promoting action of insulin and its analogues was studies in the mouse mammary tumor cell line GR2H6 by measuring 3H-thymidine incorporation. The mitogenic activity of the analogues obtained by shortening of C-terminus of insulin B chain decreased with stepwise removal of terminal residues, and [A3Leu]insulin was approximately 1000 times less potent than insulin. However, the despentapeptide (B26-B30) insulin(DPI) showed a strikingly higher mitogenic activity at high concentrations; the detected maximal effect of DPI was 136% more than that of insulin. These results demonstrate that the C-terminal area of the B chain and the N-terminal alpha-helix of the A chain are important for the mitogenic activity of insulin. A region corresponding to the growth-promoting function of insulin and a model of DPI action are proposed and discussed.

Animals↗
PubMed1997

[Diagnosis and treatment of primary malignant tumors of the small bowel].

OBJECTIVE: To study the clinical characteristics, effective diagnostic methods and therapeutic measures of primary malignant tumors of the small bowel so as to improve therapeutic effect. METHODS: In this paper 75 cases of primary malignant tumors of the small bowel were analyzed. Survival rates were calculated with Life Table, and computer Cox multivariate analysis model was used for survival analysis. RESULTS: The most frequent clinical manifestations of primary malignant tumors of the small bowel were abdominal pain, abdominal mass, emaciation and intestinal obstruction. Gastrointestinal barium meal roentgenography was performed in 13 cases, with an accurate diagnostic rate of 84.6%. The 1-,3- and 5-year survival rate after radical resection was 87.5%, 68.7% and 48.1%, respectively, while that for palliative resection was 57.9%, 33.8% and 24.1%, respectively. The factors including age, histological type, tumor site and type of resection were selected into Cox model in survival analysis. CONCLUSION: For primary malignant tumors of the small bowel, gastrointestinal barium meal roentgenography is the most valuable method for diagnosis, and surgical radical resection is the most effective therapy. The significant prognostic factors are age, histological type, tumor site and type of resection. Chemotherapy had no effect on prognosis.

Adenocarcinoma↗
PubMed1997

[Interactions among stimulators of bone resorption in organ culture].

The labeled 45Ca long bone shafts of 19 day fetal rats in organ culture was used in the study. Actions and interactions between various concentrations of LPS, TNF, LTA and PGE were quantitatively analysed by sample channels ratio method. The results indicated that they could all induce bone resorption in organ culture and show significance of differences assessed using student's test (P < 0.05). Interacts between LPS and TNF, LPS and PGE, TNF and PGE were greater than the sum of the individual responses when added together (the expection value), LPS and LTA, TNF and LTA were equal to the expection value, but LTA and PGE were less than the expection value. The result supported that the interactions among these stimulators of bone resorption were important in the pathogenesis of bone loss in periodontal disease.

Animals↗
PubMed1997

[A seroepidemiological study of hepatitis viruses among the patients with different types of liver disease in Qinhuangdao].

This article described a seroepidemiological surveillance in 326 patients with different clinical types of liver disease (acute hepatitis, AH; chronic hepatitis, CH; liver cirrhosis, LC; hepatocellular carcinoma, HCC) from hospitals in Qinhuangdao city during 1992-1995. The results showed that HAV infection could not develop chronic hepatitis. Among 238 patients of CH, LC, and HCC, anti-HAV IgM was not detected. HBV infection was the main pathogenic factor of CH, LC, and HCC with an infection rates of 77.78%, 84.21%, and 94.29%, respectively, the average rate of infection was 3.8 times higher than that in AH. HCV infection rate was increased gradually with development of chronic liver syndrome. Anti-HCV positive rate was 5.56% in CH, but 14.74% and 20.00% in LC and HCC respectively. HEV infection was found in patients with all types of liver disease with an average positive rate of 13.19%. It was not found that single HEV infection developed in CH, LC, and HCC. The average rate of super infection was 17.18% among all the patients, but the super infection rate in LC and HCC was 1.93 times higher than that in AH and CH. It seems that the super infection of HBV and HCV was the main factor for worsened liver symptoms and for developing LC and HCC.

Adolescent↗
PubMed1997

Diagnosis of intrathoracic masses by transesophageal color Doppler echocardiography.

OBJECTIVE: To evaluate the value of transesophageal color Doppler echocardiography in the diagnosis of intrathoracic masses. METHODS: Twenty patients with intrathoracic masses were examined by transesophageal echocardiography (TEE), including 12 patients with central lung masses and 8 with mediastinal masses. The neoplasms were explored by two-dimensional realtime ultrasonography, Doppler color flow imaging (DCFI) and pulsed Doppler (PD). The results were compared with computed tomography (CT), operative and pathological examination findings. RESULTS: We were able to identify the size, structure (solid or cystic), anatomic relationship, metastatic lymph nodes and venous carcinoembolus of the masses. Furthermore, the hemodynamic data in the vasculature inside the masses were detected. CONCLUSIONS: As a new method, TEE with Doppler technique is not only valuable in differentiating malignant and benign neoplasms but also useful for preoperative evaluation of the mass resectability in patients with intrathoracic neoplasms.

Adult↗
PubMed1997

[The study of DSX-I type microcomputer autometic control injector system].

This paper studies the propulsive force of injector system controlled by 8031 single-chip microcomputer for Medical use By using one 8031 single-chip microcomputer as a microprocessor, the minimal autometic control system is constructed, which turns real-time control into reality. This product is a modern appliance used in diagnostic imaging medicine, in design of which the advanced instrument and electrical machinery are integrated into a unified structure. The clinic data demonstrate that the contrast medium can be injected to patients with rapidly and evenly. Dynamic CT Scanning can be intensified at any site of the body. x-ray dose exposed and lobour intensity to the operator can be decreased greatly, raise working efficiency.

Automation↗
PubMed1997

[The value of electronystagmography in differential diagnosis of vertigo].

Findings of electronystagmography (ENG) in 645 patients with vertigo were analysed. Two hundred and twelve cases showed vestibular peripheral vertigo, 394 cases vestibular central vestigo, and 39 cases other types of vertigo. The ENGs in patients with vestibular peripheral vertigo were charazterized mainly by the vestibular abnormal caloric responses, spontaneous and benign positional nystagmuses were also obsedrved at the same time. Different degrees and various combinations of the abnormal responses shown in optokinetic central test were the most characteristic of ENG in patients with vestibular central vertigo. The results suggest that ENG is particularly useful for differentiating peripheral and central vertigo.

Adolescent↗