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Biomedical subjects

S M Niu

Publications and source records attributed to S M Niu.

8 recordsLinked to original sources
PubMed2005

Antioxidant activity of gallic acid from rose flowers in senescence accelerated mice.

The activities of the antioxidant enzymes catalase (CAT) and glutathione peroxidase (GPx) in the blood and liver of the aging model induced by injection of different doses of D-gal into normal mice, and in senescence accelerated mice (SAM) of different ages, were determined. The results showed that the enzyme activities in the D-gal treated mice did not alter appreciably but the enzyme activities in blood of the SAM declined significantly with the increase in age, especially in the 9-month-old SAM. When gallic acid purified from rose flowers was used to treat the 9-month-old male SAM, it not only reinstated the activities of CAT and GPx but also significantly reduced the amount of malondialdehyde (MDA) in the liver, brain and kidney. The results demonstrated that 9-month-old male SAM represent an appropriate animal model to evaluate the antioxidant activities of natural products.

Aging↗
PubMed2005

Rose (Rosa rugosa)-flower extract increases the activities of antioxidant enzymes and their gene expression and reduces lipid peroxidation.

The effects of rose-flower extract on antioxidant enzymes were studied. The activities of catalase (CAT) and glutathione peroxidase (GPx) in 9-month-old senescence-accelerated mice (SAM mice) were lower than those in 6-month-old SAM mice. Therefore, 9-month-old SAM mice were the most appropriate targets for treatment with the rose-flower extract. The activities of CAT and GPx in SAM mice treated with rose-flower extract showed a marked increase in whole blood and liver. At the same time, the gene-expression level of CAT and GPx was upregulated in the liver, while malondialdehyde content in liver and brain decreased. Male SAM mice were more sensitive than female SAM mice. The mean and the longest lifespan of SAM mice were longer after treatment with rose-flower extract.

Aging↗
PubMed2004

A gallic acid derivative and polysaccharides with antioxidative activity from rose (Rosa rugosa) flowers.

In this study, the major antioxidant components of rose flower were identified. An aqueous extract of rose flowers was chromatographed on CM-cellulose in ammonium acetate buffer (10 mM, pH 4.5) to yield three un-adsorbed peaks F1, F2 and F3. Each of these peaks was subjected to gel filtration on Sephadex G75. F1 yielded two peaks, whereas both F2 and F3 gave rise to only a single peak. Spectroscopic studies using NMR and FTIR revealed that F3 is a gallic acid derivative. It exhibited the highest antioxidative potency. F1-a derived from F1 by gel filtration is mainly a polysaccharide-peptide complex with less potent antioxidative activity. F2 is a polysaccharide also with reduced antioxidant activity. This study demonstrates, for the first time, the presence of both gallic acid derivatives and polysaccharides as major antioxidant principles of the aqueous extract of rose flowers.

Animals↗
PubMed1994

[The clinical significance of aberrant HLA-DR antigen expression on thyrocytes].

500 Tru-cut thyroid tissue specimens were analyzed by ABC immunohistochemistry technique by using monoclonal antibodies specific for activated lymphocytes, cytokines and HLA-DR antigen. The study revealed that DR antigen expression on thyrocytes was positively correlated with the total number of thyroid infiltrating cells, the percentage of Tac + cells, TLiSA1 + cells, T9+ cells, interferon-r+ cells, interleukin-2+ cells, especially I2+ cells, tumor necrosis factor+ cells and also positively correlated with serum TSH, thyroid microsomal antibody, thyroid globulin antibody levels. The DR expression on thyrocytes was most intense in autoimmune thyroiditis, with subacute thyroiditis, thyrotoxicosis with thyroiditis, Graves disease, goiter following in sequence and thyroid tumor being the weakest. Thyroxine treatment can suppress DR expression on thyrocytes. Our data suggest that the extent of DR expression on thyrocytes may be regarded as a new important index for clinical diagnosis, prognosis and evaluation of the therapeutic results.

HLA-DR Antigens↗
PubMed1990

[Analysis of mononuclear cell subsets infiltrated and DR-positive epithelial cells in autoimmune thyroid diseases].

Specimens of thyroid tissue from 37 cases of autoimmune thyroiditis (AT), 13 cases of thyrotoxicosis accompanied with thyroiditis (TTOT), and 23 cases of Graves' disease (GD) were analyzed by immunohistochemistry with monoclonal antibodies. The majority of infiltrating mononuclear cells were learnt to be T cells. T+4 cells were abundant in lymphoid follicles and many T+8 cells were noticed in those areas with advanced destruction. B lymphocytes were predominantly located at the germinal centers. Most importantly, DR-positive thyroid epithelial cells were significantly increased with intense lymphocytes infiltration and severe destruction of the thyroid architecture. The percentage of T cell subpopulations, B cells, macrophages were somewhat similar. Anyhow, the increase of total number of infiltrating cells and the extent of inflammatory injury were remarkable in GD, TTOT and AT. The results support the idea that some GD cases may further develop in to autoimmune thyroiditis later.

CD4-Positive T-Lymphocytes↗
PubMed1989

Effect of extract of Hirudo Medicinalis L. against adherence of calcium oxalate crystals to acid-injured bladder mucosa.

The effect of extract of Hirudo Medicinalis L. on preventing the adhesion of calcium oxalate crystals to 0.1 M hydrochloric acid-injured bladder urothelium of the rat was studied. It was found that in this species the extract coated to the bladder mucosa after it was instilled into the chemically injured bladder; and the adhesion of calcium oxalate crystals was prevented. In regard to the anti-adhesion property the Hirudo extract appears more effective than heparin, a documented glycosaminoglycan.

Adhesiveness↗