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Biomedical subjects

J Sun

Publications and source records attributed to J Sun.

At least 19 recordsLinked to original sources
PubMed1992

Nucleolar and cytoplasmic localization of annexin V.

The subcellular localization of annexin V in cultured human umbilical vein endothelial cells, epithelial cells and fibroblasts was examined. Indirect immunofluorescence and immunoblotting studies using affinity-purified anti-annexin V antibodies revealed that annexin V is located within the cytoplasm and nucleus of these cells. Further examination and direct binding studies showed that annexin V within the nucleus is associated with the nucleolus. These findings suggest that annexin V may play a role in a nucleolar function, such as ribosome assembly and transport.

Annexin A5↗
PubMed1992

The histone mRNA 3' end is required for localization of histone mRNA to polyribosomes.

The final step in mRNA biosynthesis is transport of the mRNA from the nucleus to the cytoplasm. Histone genes from which the 3' stem-loop has been deleted are transcribed to give RNAs with heterogeneous 3' ends. These RNAs are localized in the nucleus and are stable. Addition of the histone 3' processing signal either on short (< 250 nts) or long (> 1000 nts) transcripts restores 3' processing and transport of the mRNA to the cytoplasm. In addition chimeric histone-U1 snRNA genes which produced RNAs with either histone or U1 3' ends were analyzed. Transcripts which ended with U1 snRNA 3' ends were not efficiently localized to polyribosomes. However, transcripts containing the same sequences including the snRNA 3' end followed by the histone 3' end were present in the cytoplasm on polyribosomes. Taken together these results suggest that the histone 3' end is required for export of histone mRNA to the cytoplasm and association of the mRNA with polyribosomes.

Animals↗
PubMed1992

Increased numbers of T cells recognizing multiple myelin basic protein epitopes in multiple sclerosis.

Myelin basic protein (MBP)-autoreactive T cells have a crucial pathogenetic role in experimental allergic encephalomyelitis (EAE) and certain MBP epitopes may be immunodominantly recognized. The heterogeneity and quantity of the T cell response to different epitopes of MBP in multiple sclerosis (MS) and non-MS controls is not so clearly defined. We now study T cell reactivity to six different peptides of MBP in MS compared to controls in short-term cultures of blood mononuclear cells by measuring numbers of T cells that secrete interferon-gamma in response to antigen. In comparison with controls, MS patients showed dramatically increased numbers of MBP peptide-reactive T cells with mean values varying between 10.4 and 22.5 per 10(5) blood mononuclear cells. Among those MBP peptides examined (amino acid 1-20, 63-88, 89-101, 96-118, 110-128 and 148-165), no single peptide is preferentially recognized. Neither is any preferential response apparent after subdivision of the MS patients according to their HLA-DR genotype. Our findings suggest that a quantitative increase of a broad repertoire of myelin-autoreactive T cells with capacity to secrete IFN-gamma can be important for the pathogenesis of MS.

Adult↗
PubMed1992

Amino alcohol modulation of hippocampal acetylcholine release.

The synthesis and release of 3H-acetylcholine was measured in hippocampal slices of adult rat brain following acute in vitro exposure to ethanolamine. Evoked release of 3H-acetylcholine was elevated by 60-70% but 3H-acetylcholine synthesis was unaffected. Other amino alcohols were also found to significantly increase evoked 3H-acetylcholine release. The effect may be stereochemically mediated since only one of four possible propanolamine configurations, R-alaninol, was active. The most potent compound tested was R-prolinol which showed an EC50 nearly 10-fold lower than that of either R-alaninol or ethanolamine; S-prolinol was inactive. Slices taken from adult rats which had been fed active compounds for two weeks also exhibited enhancements in evoked 3H-acetylcholine release. These results indicate that amino alcohols modulate acetylcholine release in the rat hippocampus.

Acetylcholine↗
PubMed1992

[Conditions for dextranase formation by Paecilomyces lilacinus].

Induced formation conditions of dextranase by Paecilomyces lilacinus were investigated. Effect of various carbohydrates on dextranase formation was examined, dextran was the best C-source and as an inducer. The effect of dextran with different molecular weight (from 17.2 to 1000 kD) on dextranase formation was compared, productivity of dextranase increased with increase of dextran molecular weight. When dextran of 1000 kD was used as C-source. The enzyme formation was 40% higher than that 17.2 kD dextran. When other sugars were separately added to the medium with dextran, the enzyme formation was repressed. Besides C-source, the other optimum conditions of dextranase formation were as follows: N-source, beef peptone; medium initial pH, 6.0-7.0; culture temperature, 28 degrees C; inoculum amount about 10%, and the organism was cultivated for 6 days on 200 r/min shaker in 250 ml flasker with 50 ml medium.

Carbohydrates↗
PubMed1992

[Study on the recovery of 4 types of cultured cell after contacting varieties of dental casting alloys].

Four types of cultured cell (Gin-1, Chang Liver, HEP-2 and L-929) were used in vitro to determine the cytotoxicity of 12 Chinese-Japanese Dental Casting Alloys from cell recovery ability. A new cytocompatibility detecting method--cell recovery test was established and recommended. This method can be able to observe the state of cell recovery through self growth cycle, diminish the side-effect of dead cell and its products on the living cells, nearly mimic the environment in vivo and study the inherited toxicology of cells. The application of computer photo-pattern analysis technique can acquire the objective and accurate data directly.

Animals↗
PubMed1992

[Types of flowering branch of Magnolia denudata Desr. under high yield conditions].

The types of flowering branch of Magnolia denudata under high yield conditions were investigated. The action of axillary flowering branches on yield increase and the cultural techniques of promoting axillary flowering branch formation were evaluated. Under the same culturing conditions M. denudata var. dilutipurpurascens has hardly any axillary flowering branches.

Medicine, Chinese Traditional↗
PubMed1992

Magnetic resonance imaging in hepatolenticular degeneration. Analysis of 9 cases.

Nine patients with biochemically proved Wilson's disease underwent magnetic resonance imaging (MRI) of the brain. Areas of abnormal signal, long T1 and long T2, caused by gliosis and edema were seen in the lenticula, thalami, caudatum, brain stem as well as in the dentate nuclei. The abnormalities were bilateral and symmetric. Asymmetric focal white matter lesions were noted in a few patients. Focal atrophies were seen in the head of caudatum. Symmetric cavitations were only seen in the lenticular nuclei. Acute progressive type (2 patients) was characterized by cavity formation, and chronic progressive type (7 patients) by gliosis, edema and focal atrophy.

Adolescent↗
PubMed1992

Effects of lead exposure on porphyrin metabolism indicators in smelter workers.

A study on the dose-effect relationship between blood lead level and FEP, ZPP, CPU, and ALAU among 250 lead smelter workers was conducted. A nonlinear regression model of a dose-effect relationship between blood lead and porphyrin metabolism indicators was established. The upper limit of normal values of these indicators were estimated from blood lead levels by these nonlinear regression equations. The diagnostic significance was evaluated by multiregression and discriminant analysis. This study would be helpful to the decision-making policy in revising the current diagnostic criteria for occupational lead poisoning.

Adult↗
PubMed1991

T and B cell responses to myelin-oligodendrocyte glycoprotein in multiple sclerosis.

The pathogenesis of multiple sclerosis (MS) is believed to involve an autoimmune component directed against the myelin sheath. One potential target Ag for such autoimmune attack is the myelin-oligodendrocyte glycoprotein (MOG) because an anti-MOG mAb has profound influence on the course of experimental autoimmune encephalomyelitis, which to some extent represents an experimental model of MS. Using single cell assays, we have evaluated T and B cell reactivities to MOG in MS patients and controls. T cell reactivity was estimated by counting the number of cells that secreted IFN-gamma in response to MOG, whereas B cell reactivity was estimated by enumerating cells secreting antibodies that bound to MOG. MOG reactive T cells were detected in the peripheral blood of the majority of the 16 MS patients examined (mean 1/7299 mononuclear cells), but infrequently and at lower numbers in samples from neurologic controls. MOG-reactive T cells were more frequent among MS patients' cerebrospinal fluid (CSF) mononuclear cells (mean 1/450 cells). The T cell response to MOG was evidently MHC class II restricted, because Fab fragments of a rabbit polyclonal anti HLA-DR antibodies abrogated the Ag-induced increase in number of cells that secreted IFN-gamma, as analyzed on CSF and PBMC from three patients with MS. Anti-MOG IgG antibody-secreting cells were detected in blood in 8 of 16 MS patients (mean 1/25,641 cells), but they were also strongly accumulated in CSF, being detected in 8 of 10 MS patients examined (mean 1/265 cells), while rarely found in controls. The findings imply that MOG may represent a pathogenetically important target Ag in MS.

Adult↗
PubMed1991

Cord blood contains cells secreting antibodies to nervous system components.

Umbilical cord blood of newborns and peripheral blood of healthy adults were investigated by an immunospot assay for cells secreting IgG, IgA and IgM antibodies against myelin basic protein (MBP), proteolipid protein (PLP), myelin-associated glycoprotein (MAG) and myelin oligodendrocyte glycoprotein (MOG) which represent putative antigens for an autoimmune attack in multiple sclerosis (MS) and against acetylcholine receptor (AChR) which is considered an important autoantigen in myasthenia gravis. Cells secreting antibodies against one or more of these autoantigens were detected in 18 out of 24 newborns, and in eight out of 20 adults. Eight of the cord blood samples contained cells secreting antibodies of IgG, IgA and/or IgM isotypes to one antigen, five to two antigens, two to three antigens, two to four antigens, and one to five antigens. Most prominent were anti-MBP IgG antibody secreting cells which were detected in 13 newborns at a mean number of 1/20,000 cord blood cells, and in six adults at a mean number of 1/10(5) peripheral blood cells. Anti-AChR IgG antibody secreting cells were detected in four out of 12 newborns versus four out of 14 peripheral blood specimens, at mean values of 1/10(5) cells in both instances. Cells secreting autoantibodies of IgA and IgM isotypes were less frequent both in cord blood and peripheral blood. The occurrence of nervous tissue autoantibody secreting cells in newborns must be related to a possible primary role of such autoantibodies in MS and myasthenia gravis.

Adult↗
PubMed1991

Association of a retroelement with a P4-like cryptic prophage (retronphage phi R73) integrated into the selenocystyl tRNA gene of Escherichia coli.

A new multicopy single-stranded DNA (msDNA-Ec73) was found in a clinical strain of Escherichia coli. Retron-Ec73, consisting of an msDNA-coding region and the gene for reverse transcriptase (RT), was found to be a part of a 12.7-kb foreign DNA fragment flanked by 29-bp direct repeats and integrated into the gene for selenocystyl-tRNA (selC) at 82 min on the E. coli chromosome. Except for the 2.4-kb retron region, the integrated DNA fragment showed remarkable homology to most of the bacteriophage P4 genome. Among the phage genes found in this element, however, the integrase gene had very low identity (40%) to P4 integrase, indicating that the cryptic prophage associated with the retroelement has its own unique site-specific integrase different from P4 integrase. Recently, we have shown that P2 phage can act as a helper to excise the cryptic prophage and to package its genome into an infectious virion. The newly formed phage (retronphage phi R73) can also lysogenize a new host strain, reintegrating its genome into the selC gene and enabling the newly formed lysogen to produce msDNA-Ec73 (S. Inouye, M. G. Sunshine, E. W. Six, and M. Inouye, Science 252:969-971, 1991).

Amino Acid Sequence↗
PubMed1991

Acetylcholine receptor-reactive T and B cells in myasthenia gravis and controls.

Myasthenia gravis (MG) is strongly associated with antibodies to acetylcholine receptor (AChR), whereas the extent of T cell involvement is not settled. The number of cells secreting interferon-gamma (IFN-gamma) in response to AChR during 48 h culture of blood mononuclear cells (PBL) may reflect AChR-reactive T cells. Using an immunospot assay, we detected such cells in 23 of 30 patients with MG at a mean number of 1 per 33.333 PBL. AChR-reactive T cells were also found in patients with other neurological diseases (OND) and in healthy subjects but at lower frequencies and numbers. The T cell response to purified protein derivative and to PHA, and also to two major myelin proteins (basic protein and proteolipid protein) did not differ between MG and the two control groups, underlining the specificity of an augmented T cell reactivity to AChR in MG. Evaluation of the B cell response by enumerating anti-AChR IgG antibody secreting cells revealed such cells in 27 of 28 patients with MG at a mean value of 1 per 14,085 PBL. Cells secreting anti-AChR antibodies of the IgA and IgM isotypes were also detected in MG, but less frequently, at lower numbers, and only in conjunction with IgG antibody secreting cells. Anti-AChR antibody secreting cells were also found among patient with OND and in healthy controls, but at lower frequencies and numbers. These data confirm that AChR is a major target for autoimmune response in MG.

B-Lymphocytes↗
PubMed1991

[Differentiation of Magnolia denudata Desr. flower buds].

The article gives the results of an observation on the differentiation of Magnolia denudata buds. In Huaining County, Anhui Province, differentiation of the buds starts at the beginning of May. By the end of June the differentiation of various parts of the flower is completed. The process takes about 50 days. The differentiation of buds goes on at a fairly fast speed and in a fairly uniform way. Based on the results of the observation, the authors advise that application of fertilizer, especially the top application should not be late. The beginning of March is a very important time for the development of buds in length and size, and for the final harvest as well. The proper time to pick the flower buds comes when they are fully developed before the perianth appears.

Fertilizers↗
PubMed1991

The association between cervical carcinoma and human papilloma virus (HPV) in Xiangyuan County.

A mass survey was conducted to investigate the association between cervical carcinoma and human papilloma virus (HPV) infection in a high-risk area, Xiangyuan County, Shanxi Province. Fifty-four cases of cervical cancer in situ (CIS), including severe dysplasia (CIN III), 14 cases of invasive cervical carcinoma, 28 cases of mild cervical dysplasia (CIN I), and 13 cases of moderate cervical dysplasia (CIN II) were identified among 6710 women examined. One hundred and sixty-nine punch biopsies from abnormal cervix and genital tract were examined for the presence of HPV 6B/11, 16 and 18 DNA sequences by dot blot hybridization: The positive rates of HPV infection in cervicitis, CIN I, II, III, CIS and invasive cervical carcinoma specimens were 35.06% (27/77), 25% (2/8), 33.33% (2/6), 40% (2/5), 70.58% (24/34) and 40% (4/10), respectively. Among these groups, there was no regular distribution of HPV types except for HPV 16, the positive rate of which was increased from 25% in CIN I to 46.15% in CIS: HPV 16 was also the only type seen in the invasive cervical cancer group. Distribution analysis of HPV types in HPV-positive cervical cancer tissues uncovered an HPV 16 positive rate of 59.4%; 3.7 and 2.4 times higher than those of HPV 6B/11 and HPV 18, respectively. These data confirm the close association between cervical cancer and HPV 16 infection.

Adult↗
PubMed1991

[Biological characteristics of Cryptoporus volvatus (peck) Hubb., a medicinal fungus].

Through ecological investigations and experimental studies, it has been shown that C. volvatus is a fungus growing on decaying matter; the carbon source of culture medium comes from glucose, honey, fructose, mannitol, etc; and its nitrogen source from peptone, yeast powder, etc. The best ratio of carbon to nitrogen (C/N) is 20-25: 1, optimum pH 5.5-6.5 and optimal temperature 25-30 degrees C.

Culture Media↗
PubMed1991

[Hemodynamic study of external counterpulsation with left and right cardiac catheters in 15 cases].

The hemodynamic changes of 15 cases during external counterpulsation with left and right cardiac catheters were reported. The results showed that the diastolic pressure at the root of the aorta was remarkably increased, the peak value (countercurrent pressure) was 8.02 +/- 2.05 kPa higher than the diastolic pressure before counterpulsation; the aortic systolic pressure during counterpulsation was slightly decreased with a mean value of 0.81 kPa; there was no apparent change in the central venous pressure and pulmonary arterial pressure; pulmonary arterial wedge pressure was slightly reduced during counterpulsation. All the above data are useful in showing the improvement of cardiac and brain perfusion volume and clarifying its mechanism.

Adult↗