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Hepatic stimulator substance (HSS) is a novel liver-specific growth-promoting factor. Although HSS has been successfully crystallized, several properties of this protein have yet to be determined. This study shows that recombinant human HSS (rhHSS) is a dimer with a molecular mass of 31 kDa, the protein is weakly acidic and has an isoelectric point (pI) of 4.50. RhHSS was able to protect hepatoma cells from H2O2-induced apoptosis and to stimulate cell growth. The recombinant protein was thermostable up to 80 degrees C and resistant to changes in pH, as determined by synchronous fluorescence and far-UV circular dichroism (CD). Within the range of pH 4.0-10.0, rhHSS assumed a folded conformation identical to the secondary structure of the original, native protein and a native-like far-UV CD spectrum. Denatured rhHSS could be partly reconstituted with respect to its structure, but not its activity. Thus, rhHSS is a structurally stable protein insensitive to thermal and acid-alkaline denaturation.

To explore the ABCC8, KCNJ11, and GLUD1 gene mutations of the 11 patients diagnosed as congenital hyperinsulinism (CHI).A total of 11 CHI children hospitalized in Beijing Children's Hospital from November 2008 to February 2012 and their parents were chosen as the study subjects. Direct sequencing of PCR-DNA was used to analyze the 39 exons of ABCC8 gene, non-translational region and exon of KCNJ11 gene and 6, 7, 10, 11 and 12 exons of GLUD1 gene.An P629PfsX17 heterozygous mutation of ABCC8 gene was detected in case 1 and his father, an W288X heterozygous mutation of ABCC8 gene was detected in case 4 and his father, A640V and Q1196X mutations in ABCC8 gene in case 5 whose father only carried the Q1196X mutation. In case 6 and his father, an R269H mutation was found in GLUD1 gene. The genotype of 4 children's mothers was normal. No mutations were found in other 7 patients and their parents.The ABCC8 gene mutations are the main pathogenic mechanisms of Chinese children with CHI. In Chinese, P629PfsX17, W288X, A640V and Q1196X heterozygous mutation of ABCC8 gene and R269H heterozygous mutation of GLUD1 gene may lead to CHI. The inheritance mode of the mutations may be paternally or de novo.

To observe the changes of matrix metalloproteinases (MMPs) activities in pulmonary fibrosis rats.Eighty male SD rats were randomly divided into sham group (n = 40) and bleomycin group (BLM, n = 40), in which SD rats were injected with a single intratracheal dose of sham saline or bleomycin respectively. On day 1, 3, 7, 14, and 28 following bleomycin or saline instillation, rats were randomly killed, and serum from abdominal aorta, alveolar fluid from the bronchoalveolar lavage, and the lung homogenate were collected and then stored at -80 degrees C. MMPs activity was determined by zymography.Compared with sham group, the levels of MMP-9 in all samples were augmented. MMP-9 activities in the serum were highest on day 3 than those on day 1 and day 7, and in lung tissue homogenate were highest on day 7; however, no significant differences were found between BLM group and sham group on day 14 and day 28; and that of bronchoalveolar lavage fluid (BALF) was highest on day 7 than those on day 1 and day 14, while no significant difference existed between BLM group and sham group on day 28. Serum MMP-2 level did not change from day 1 to day 28, while the level of BALF MMP-2 began to increase after day 14, even on day 28. Lung tissue homogenate MMP-2 level began to increase early on day 3 and continued to day 28.The sources and effects of MMP-2 and MMP-9 differ in BLM-induced rat pulmonary fibrosis.