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Biomedical subjects

G Yuan

Publications and source records attributed to G Yuan.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Investigation of potency to produce interleukin-2 of the peripheral blood T lymphocytes in patients with hemorrhagic stroke].

For further understanding the changes in immune function of the patients with hemorrhagic stroke, we investigated the activity of interleukin-2 (IL-2) in the peripheral blood T lymphocytes from 32 patients. The results showed that the levels of IL-2 in the patients were lower than those of the healthy controls, but no significant difference was observed between the cerebral hemorrhage group and subarachnoid hemorrhage group. It suggests the cellular immune function of patients at the acute period is low. We consider that IL-2 might be of use as a kind of therapeutic measure to modulate patients' immune function and treat the diseases.

Adolescent↗
PubMed1997

[Adhesion of erythrocytes of patients with transient ischemic attack to injured endothelial cells].

Adherence of erythrocytes of patients with transient ischemic attack(TIA) to human umbilical vein endothelial cells(HUVEC) treated with H2O2 were quantitatively studied in the flow chamber system. The results showed that injured HUVECs enhanced the adherence of erythrocytes to endothelial cells in patients with TIA. The increased adhesion of erythrocytes to endothelial cells might promote the vascular damage. Consequently endothelium might play an important role in the increased adhesiveness of TIA RBC to endothelial cells.

Aged↗
PubMed1997

[Study on enterovirus aetiology of CNS infection in Shantou].

Enterovirus isolation and serological assay were done in 236 cases of CNS infection in Shantou. 62 strains of virus (from 55 cases) were isolated from 257 samples of 236 cases (24.1%). 48 cases were positive among 57 cases (84.2%) by serological assay. 78 cases were positive for virus isolation and/or serological assay (33.1%). Virus infection included 33 cases of poliovirus (including 6 polio-I, 18 polio-II, 4 polio-III, 5 mixed infections), 21 cases of Coxsackie virus (including 6 CoxA24,7 CoxB1,2 CoxB4 and 6 CoxB5), 11 cases of ECHO virus (including 5 ECHO-7,2 ECHO-24 and each one of ECHO-11, 12, 15, 27), 10 cases of Enterovirus (including 3 EV-70, 7 EV-71), and 3 cases of mixed viral infection.

Adolescent↗
PubMed1997

The embryonic development of the human lamina cribrosa.

OBJECTIVE: To investigate the embryonic development of lamina cribrosa of human eyes. METHODS: The lamina cribrosa of 291 eyes were studied including 260 eyes taken from embryos and fetus of 7 weeks to full term and 31 eyes from infants under 1 year of age by using light microscopy (LMS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). RESULTS: From observations, it was found that the development of the lamina cribrosa was lagged behind the development of the optic nerve. CONCLUSIONS: In eyes taken from embryos or fetus less than 4 months of pregnancy, only ectodermal primordium of the lamina cribrosa could be seen. The initial scleral part of the lamina cribrosa began its formation in the 5th month of fetus. The fibrous tissue originating from the choroid and optic nerve sheath contributed to the formation of the lamina cribrosa in the 8th month fetus. At this time, the morphology of the lamina cribrosa is similar to that of an adult, however the thickness of the structure is still getting increased up to one year after birth.

Choroid↗
PubMed1996

[Primary intracranial malignant lymphoma: report of 40 cases].

Primary intracranial malignant lymphoma is rate in clinic. But the incidence tends to be increasing recently. In its relatively short course, children and the slightly more woman headache vomiting IICP (increased intracranial pressure) and corresponding neurofunctional disorders due to various location of the tumors are the main clinical manifestation. Even high density which obviously increased after contrast and peripheral edema may be seen in CT scanning. MRI examination shows lowereal signals in T1 phase. But enhanced signals in T2 phase. Histologically the tumor mass is grayish in color often with a blussed borders (those located in brain surface often have rough borders) to the naked eye. Undermicroscope tumor cell may be seen around blood vessels with decreased cytosol, pathologic rayokinesis and somtimes focal hemorrhage necrosis. All patients in the 40 cases of our study group were connfirmed by surgical excision and patholog examination. Three patients died within half a year after resection. The others showed a survival period ranging from 4 to 20 months after postoperative irradiation solely or combined chemotherapy. Nine patients failed in total resection. Patients undergone postoperative irradiation but without following chemotherapy, only survived 4 to 9.7 months. Thus it can be seen that prolongation of the survival period of primary intracranial malignant lymphoma depends upon possibly early excision combined irradiation and effective chemotherapy.

Adolescent↗
PubMed1995

Safety, immunogenicity, and efficacy of a recombinantly produced Plasmodium falciparum circumsporozoite protein-hepatitis B surface antigen subunit vaccine.

Twenty malaria-naive volunteers received a recombinant Plasmodium falciparum malaria vaccine (RTS,S) containing 19 NANP repeats and the carboxy terminus (amino acids 210-398) of the circumsporozoite (CS) antigen coexpressed in yeast with hepatitis B surface antigen. Ten received vaccine adjuvanted with alum, and 10 received vaccine adjuvanted with alum plus 3-deacylated monophosphoryl lipid A (MPL). Both formulations were well tolerated and immunogenic. MPL enhanced CS antibody levels (measured by ELISA, immunofluorescence, and inhibition of sporozoite invasion assays). After sporozoite challenge, 6 of 6 in the alum group and 6 of 8 in the alum-MPL group developed patent malaria. Protected subjects had higher levels of CS antibody titers on day of challenge than did nonprotected subjects. After immunization, 1 protected subject had increased cytotoxic T lymphocyte activity against CS and recall of memory T cell responses to RTS,S and selected CS.

Adult↗
PubMed1995

Regulation of groE expression in Bacillus subtilis: the involvement of the sigma A-like promoter and the roles of the inverted repeat sequence (CIRCE).

To study the regulatory mechanism controlling the heat-inducible expression of Bacillus subtilis groE, two regulatory elements, the sigma A-like promoter and the inverted repeat (IR [CIRCE]) in the control region, were characterized. The groE promoter was shown to be transcribed by the major RNA polymerase under both heat shock and non-heat shock conditions. The IR was found to have two functions. (i) It ensures the fast turnover of the groE transcript, and (ii) it serves as an operator. This IR acts as a negative heat shock regulatory element, since deletion of this sequence resulted in high-level expression of groE even at 37 degrees C. Although this IR is present in the 5' untranslated region of the groE transcript, groE transcripts under heat shock and non-heat shock conditions showed similar in vivo half-lives of 5 min. This rapid turnover at 37 degrees C requires the presence of the IR. Without the IR, the groE transcript showed a longer half-life of 17 min. Increasing the distance between the groE transcription start site and the IR systematically by inserting nucleotide sequences from 5 to 21 bp in length resulted in a gradual abolition of the negative regulatory effect mediated by the IR. This effect was not due to a significant change in transcript stability or the transcription start site and is consistent with the model that this IR serves as an operator.

Bacillus subtilis↗
PubMed1995

Isolation and characterization of Bacillus subtilis groE regulatory mutants: evidence for orf39 in the dnaK operon as a repressor gene in regulating the expression of both groE and dnaK.

An inverted repeat sequence known as CIRCE (controlling inverted repeat of chaperone expression) in the Bacillus subtilis groE operon has been suggested to function as an operator. To identify the regulatory gene directly or indirectly involved in CIRCE-mediated heat-inducible groE expression, B. subtilis WBG2, carrying an integrated groE-bgaB transcription fusion in the amyE locus, was mutagenized. Dark blue colonies formed at 37 degrees C represent mutants which constitutively produce BgaB (a thermostable beta-galactosidase) at high levels. Seven mutants (WBG101 to WBG107) were selected for further characterization. They all overproduced BgaB, GroEL, and DnaK simultaneously at 37 degrees C. These mutants could be restored to normal by introducing a plasmid carrying a functional copy of orf39, the first gene in the B. subtilis dnaK operon. Genomic sequencing of these mutants demonstrated that they all carried a single mutation in orf39. These mutations can be divided into three groups: (i) Gly-307 to Asp, (ii) Ser-122 to Phe, and (iii) Gly-63 to Glu. By using a binary vector system in E. coli, production of ORF39 was found to negatively regulate the expression of groE-bgaB in a CIRCE-specific manner. Under the heat shock condition, the negative regulation mediated by ORF39 was abolished. Mobility shift of the CIRCE-containing probe was also observed with the crude extract prepared from the E. coli strain that overproduced ORF39. Therefore, ORF39 is the negative regulatory factor which regulates both groE and dnaK expression in B. subtilis. It is likely to function as a CIRCE-specific repressor.

Amino Acid Sequence↗
PubMed1995

[Enzyme-linked immunoadsorbent assays for myelin basic protein and antibodies to myelin basic protein in serum and CSF of patients with diseases of the nervous system].

Simplified enzyme-linked immunoadsorbent assays (ELISA) for myelin basic protein (MBP) and antibodies to myelin basic protein (Anti-MBP) have been used to test 337 patients with diseases of the nervous system including 36 compressive diseases (CMP), 33 multiple sclerosis (MS), 34 cerebrovascular diseases (CVD), 31 inflammatory diseases of central nervous system (ID), 161 epilepsy (EP) and 42 other nervous diseases (OND). Comparison of results among various groups indicates that serum mean MBP values of CMP, MS, CVD, ID and EP groups are significantly higher than those of OND group and normal control (P < 0.01). The serum mean MBP value of 33 acute trauma patients with spine fracture and paraplegia, the majority of CMP group, is the highest compared with MS group (P < 0.05), CVD, ID and EP groups (P < 0.01). CSF mean MBP value of 15 CVD patients is markedly greater than that of OND group (P < 0.05). No statistically significant differences are found in serum MBP values between OND group and normal control, and in serum and CSF Anti-MBP values among six groups by using our method.

Autoantibodies↗
PubMed1995

[Serum anti-subtypical Klebsiella pneumoniae antibodies in ankylosing spondylitis].

This study was performed in order to probe the possible pathogenesis of Klebsiella pneumoniae (KP) in ankylosing spondylitis (AS). 34 anti-KP antibody positive serum samples, including 26 patients with AS, 5 patients with rheumatoid arthritis (RA) and 2 healthy individuals, were selected to detect anti-subtypical KP antibodies by using an immunoblotting technique. The results showed that the number of antigenic bands to KP on nitrocellulose membrane was higher in AS patients than in RA patients and healthy individuals. Patients with AS had common antibodies response to KP components weight 64,600 (80.7%), 48,200 (61.5%) and 36,000 (65.4%), patients with RA and healthy individuals had anti-36,000 (75%) and anti-30,000 (50%) antibodies. Human anti-HLA-B27 serum and rabbit antisera against KP-derived synthetic peptide containing the hexapeptide sequence shared by HLA-B27 were able to cross react with 64,600 and 48,200 KP components. Our findings suggest that KP might play a role in the pathogenesis of AS by molecular mimicry between it and HLA-B27.

Antibodies, Bacterial↗
PubMed1995

[Adhesion of erythrocytes of patients with cerebral thrombosis to injured endothelial cells].

Using flow chamber system, we quantitatively studied the adhesion of erythrocytes (RBCs) of patients with cerebral thrombosis (CTh) to cultured human umbilical vein endothelial cells (HUVECs) treated with H2O2. The results showed that injured HUVECs enhanced adhesion of RBCs to HUVECs in patients with CTh. There is injury of endothelial cells in the pathogenetic and pathologic process of CTh, and the adhesion of RBCs to ECs promotes vaso-occlusive and vascular damage; thus the adhesion of RBCs to injured ECs might play an important role in the pathogenesis and pathologic process of CTh.

Aged↗
PubMed1995

[The effects of Salvia miltiorrhiza and polysaccharide sulphate on the adhesion of erythrocytes of the patients with cerebral thrombosis to cultured endothelial cells].

Salvia miltiorrhiza and polysaccharide sulphate are commonly prescribed for curing cerebral vascular diseases. In this study, we found that the adhesion of erythrocytes of the patients with cerebral thrombosis to cultured human umbilical vein endothelial cells was decreased in number and intensity after the erythrocytes were treated with salvia miltiorrhiza and polysaccharide sulphate in flow field. Moreover we found that polysaccharide sulphate was more effective than salvia miltiorrhiza in preventing adherence in common doses. The two drugs' effects of preventing adherence might be an important mechanism for curing the patients with cerebral thrombosis.

Aged↗