👤 Jialu Song

Hereditary multiple exostoses (HME) is an autosomal dominant disorder characterized by formation of benign cartilage-capped tumors (exostoses), typically located at the juxtaepiphyseal regions of long bones. It is genetically heterogeneous with at least three chromosomal loci: EXT1 on 8q24.1, EXT2 on 11p11, and EXT3 on 19p. EXT1 and EXT2 have been cloned and are responsible for over 80% of cases. A Chinese family with HME has been analyzed in the present study. Linkage analysis was firstly performed to determine which of the three EXT genes could be the candidate gene, then mutation screening by PCR and direct sequencing was carried out. A novel nonsense mutation (c.1006C>T) in exon 6 of EXT2, which converts the codon CAA (Gln) to the stop codon (TAA) (Gln336X), was identified. Next, prenatal diagnosis was performed and the pregnancy was determined to be normal. A new EXT2 nonsense mutation was found in a Chinese family with hereditary multipe exostoses. The information was used for a case of prenatal diagnosis. Show less

To identify the disease-causing gene mutations and to reveal the relationship between the genotype and the phenotype in Chinese patients with hypertrophic cardiomyopathy (HCM). One hundred unrelated patients with HCM and 120 controls were enrolled in this study. The full encoding exons and flanking sequences of the cardiac myosin binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced. A novel missense mutation c.706T > C was identified in exon 6 of MYBPC3 gene in three HCM patients, which resulted a Serine (S) to Glycine (G) exchange at amino acid residue 236 (S236G). The clinical phenotypes of the three patients were different (2 obstructive HCM, 1 non-obstructive HCM). The 120 controls were normal in the genetic test. The novel S236G mutation in MYBPC3 gene was a hot-spot mutation in Chinese patients with HCM. Show less

To investigate the genotype-phenotype correlation in Chinese familial hypertrophic cardiomyopathy (HCM), peripheral blood samples were collected from 7 members of a Chinese HCM family, and 120 normal subjects were recruited as control. The full encoding exons and flanking sequences of the cardiac troponin T (TNNT2) gene, beta-myosin heavy chain (MYH7) gene and myosin binding protein C (MYBPC3) gene were amplified and the products were sequenced directly to detect the mutations. A missense mutation, c.1273G>A, was identified in exon 14 of the MYH7 gene in 4 members of the Chinese HCM family, which resulted a glycine (Gly) to arginine (Arg) exchange at amino acid residue 425. The 425th glycine amino acid residue is highly conservative across the different species. The clinical phenotypes among the family members who carried this mutation presented significant individual differences. The c.1273G>A mutation of the MYH7 gene might be the causal mutation of the familial HCM. The heterogeneity of phenotypes suggested that multiple factors may be involved in the pathogenesis of HCM. Show less

Clearance of cellular debris is a critical feature of the developing nervous system, as evidenced by the severe neurological consequences of lysosomal storage diseases in children. An important developmental process, which generates considerable cellular debris, is synapse elimination, in which many axonal branches are pruned. The fate of these pruned branches is not known. Here, we investigate the role of lysosomal activity in neurons and glia in the removal of axon branches during early postnatal life. Using a probe for lysosomal activity, we observed robust staining associated with retreating motor axons. Lysosomal function was involved in axon removal because retreating axons were cleared more slowly in a mouse model of a lysosomal storage disease. In addition, we found lysosomal activity in the cerebellum at the time of, and at sites where, climbing fibers are eliminated. We propose that lysosomal activity is a central feature of synapse elimination. Moreover, staining for lysosomal activity may serve as a marker for regions of the developing nervous system undergoing axon pruning. Show less

Plasma liver-enzyme tests are widely used in the clinic for the diagnosis of liver diseases and for monitoring the response to drug treatment. There is considerable evidence that human genetic variation influences plasma levels of liver enzymes. However, such genetic variation has not been systematically assessed. In the present study, we performed a genome-wide association study of plasma liver-enzyme levels in three populations (total n = 7715) with replication in three additional cohorts (total n = 4704). We identified two loci influencing plasma levels of alanine-aminotransferase (ALT) (CPN1-ERLIN1-CHUK on chromosome 10 and PNPLA3-SAMM50 on chromosome 22), one locus influencing gamma-glutamyl transferase (GGT) levels (HNF1A on chromosome 12), and three loci for alkaline phosphatase (ALP) levels (ALPL on chromosome 1, GPLD1 on chromosome 6, and JMJD1C-REEP3 on chromosome 10). In addition, we confirmed the associations between the GGT1 locus and GGT levels and between the ABO locus and ALP levels. None of the ALP-associated SNPs were associated with other liver tests, suggesting intestine and/or bone specificity. The mechanisms underlying the associations may involve cis- or trans-transcriptional effects (some of the identified variants were associated with mRNA transcription in human liver or lymphoblastoid cells), dysfunction of the encoded proteins (caused by missense variations at the functional domains), or other unknown pathways. These findings may help in the interpretation of liver-enzyme tests and provide candidate genes for liver diseases of viral, metabolic, autoimmune, or toxic origin. The specific associations with ALP levels may point to genes for bone or intestinal diseases. Show less

To study the disease-causing gene mutations in familial hypertrophic cardiomyopathy (HCM) in Chinese and to reveal the relationship between the genotype and the phenotype. Peripheral blood samples were collected from 12 members of a HCM family, and 120 healthy volunteers in China. PCR and double deoxygenation chain termination method were used to analyze the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7) gene and myosin binding protein C gene (MYBPC3) and to detect mutations. Mutation G14452A was identified in exon 22 of MYH7 gene in 4 family members, causing the conversion of glycine (G) into glutamic acid (E). The onset ages and clinical manifestations of the family members carrying the mutation G823E, including 2 patients (the proband, male, with the onset age of 51, and his 26-year-old second son with the onset age of 20), and 2 carriers (his 31-year-old elder son and 29-year-old elder daughter), presented significant individual differences. The G823E mutation of MYH7 gene is the causal mutation of familial HCM. The heterogeneity of phenotypes suggests that multiple factors may be involved in the pathogenesis of HCM. Show less

To reveal genotype-phenotype correlation of disease-causing gene mutations in Chinese hypertrophic cardiomyopathy (HCM) pedigree. Peripheral venous blood samples were collected from two Chinese HCM families and 120 healthy subjects were recruited as normal control. The full encoding exons and flanking sequences of the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7) and myosin binding protein C gene (MYBPC3) were amplified with the polymerase chain reaction method, DNA sequencing was used to detect the mutation. In ZZJ family, mutation G12101A was identified in exon 21 of MYBPC3 gene in 4 family members [the arginine (R) converted to histidine (H)]. In this pedigree, three out of eight family members were diagnosed as HCM and with a penetrance of 75%. In FHL family, mutation G15391A was identified in exon 23 of MYH7 gene in 3 family members [the glutamic acid (E) converted to lysine (K)]. In this pedigree, three out of six family members were diagnosed as HCM and with a penetrance of 100%. Echocardiography showed obstruction of left ventricular outflow tract in two out of the three HCM patients. Our results showed that the G12101A mutation of MYBPC3 gene is the causal mutation of familial HCM with mild phenotype. The G15391A mutation of MYH7 gene is the causal mutation of familial HCM with malignant phenotype and a penetrance of 100%. Screening mutations in the MYH7 gene should be viewed as a reasonable procedure in obstructive HCM patients. Show less

No data are available on survival analysis and longitudinal evolution of patients with gene mutations of beta-myosin heavy chain (MYH7) and myosin binding protein C (MYBPC3) in Chinese. To prospectively investigate whether different gene mutations confer distinct prognosis. We performed a prospective study in 70 HCM patients and 46 genetically affected family members without HCM-phenotype with direct DNA sequencing of MYH7 and MYBPC3, clinical assessments, and 5.8 +/- 1.8 years follow-up. After follow-up, more surgical intervention (8/52 versus 0/18, p < 0.001), higher sudden death risk (7/52 versus 0/18, p < 0.001) and shorter life span were found in patients with MYH7 mutations than in patients with MYBPC3 mutations (45.1 +/- 14.0 versus 73.5 +/- 7.5 years, p = 0.03). Seven of the 27 mutation carriers of MYH7 had clinical presentations of HCM, but no carriers of MYBPC3 mutations developed to HCM during follow-up. Maximal wall thickness was thicker in the patients carrying mutations in the global region of MYH7 than in those carrying mutations in the rod region of MYH7 (21.5 +/- 6.6 versus 15 +/- 6.1 mm, p < 0.05) at baseline. More sudden death (7/41 versus 0/11) and left ventricular dysfunction (NYHA Class III approximately IV, 17/32 versus 1/10) were identified in patients with mutations in the global region of MYH7 than in patients with other mutations. MYH7 mutations, especially in the global region, cause malignant clinical phenotypes. Show less

In addition to its role as the primary mediator of the enteroinsular axis, glucose-dependent insulinotropic polypeptide (GIP) may play a critical role in the development of obesity. The purpose of these studies was to characterize the effects of GIP and its receptor (GIPR) in adipocyte development and signaling. Effects of GIP and GIPR on differentiated 3T3-L1 cells were analyzed using Western blot analysis, Oil-Red-O staining, cyclic adenosine monophosphate radioimmunoassay, immunofluorescence microscopy, and glucose uptake measurements. To determine whether GIP and GIPR are important components in adipocyte development, the expression profile of GIPR during differentiation was examined. GIPR protein expression was enhanced during the differentiation process, and coincubation with its ligand GIP augmented the expression of aP2, a fat cell marker. Conversely, the suppression of GIPR expression by a specific short hairpin RNA attenuated Oil-Red-O staining and aP2 expression, suggesting that the GIPR may play a critical role in adipocyte development. To investigate specific signaling components that may mediate the effects of GIP, we analyzed Akt, glucose transporter-4, and glucose uptake, all of which are modulated by insulin in fat cells. Like insulin, GIP induced the activation of Akt in a concentration-dependent manner, promoted membrane glucose transporter-4 accumulation, and enhanced [(3)H]-2-deoxyglucose uptake. These studies provide further evidence for an important physiologic role for GIP in lipid homeostasis and possibly in the pathogenesis of obesity. Furthermore, our data indicate that the GIPR might represent a suitable target for the treatment of obesity. Show less

To study the disease-causing gene mutation in Chinese patients with familial hypertrophic cardiomyopathy (FHC) and to analyze the correlation between the genotype and the phenotype. Peripheral blood samples were collected from 40 members from a family affected with FHC, and 120 healthy volunteers. PCR was performed to analyze the exons and flanking introns of the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7), and myosin-binding protein C gene (MYBPC3) and the products were sequenced. The clinical data including symptom, physical examination, echocardiography and electrocardiography were collected. A 14035c > t mutation, which causes a missense mutation (R130C) in exon 10 of TNNT2 gene were identified in 4 family members, including the proband, female, aged 53, with the onset at the age of 30. The 4 persons with the 14035c > t mutation, all FHC patients, presented left ventricular dysfunction with a penetrance of 100%. Two of the patients died of sudden cardiac death during follow-up. No mutation was identified in the MYH7 and MYBPC3 genes. The 14035c > t mutation of TNNT2 gene is the causal mutation of FHC which is associated with malignant phenotype with a penetrance of 100%. It is a reasonable procedure in HCM patients with malignant phenotype to screen mutation in the TNNT2 gene. Show less

To study the disease-causing gene mutation in Chinese patients with hypertrophic cardiomyopathy (HCM) and to analyze the genotype and phenotype correlation. One family (n = 27) affected with HCM were chosen for the study. The full encoding exons and flanking sequences of beta-myosin heavy chain gene (MYH7) and cardiac myosin-binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced. The clinical data including symptom, physical, echocardiography and electrocardiography examinations were collected. We identified a 13261 G > A mutation, which causes a missense mutation (G758D) in exon 23 of MYBPC3 in 9 family members. One mutation carrier suffered from dilated cardiomyopathy (DCM) with asymmetric interventricular septal hypertrophy (14 mm). Another mutation carrier was diagnosed as HCM. The 13261 G > A mutation is associated with a DCM-like HCM and HCM phenotype in this Chinese family affected with HCM. Show less

Ulcerative colitis is characterized by crypt infiltration particularly of neutrophils. However, it is not known whether it reflects a primary crypt disorder or a secondary inflammatory response. In this study, we analyzed the expression profiles of histologically normal crypts microdissected from formalin-fixed biopsies of early stage ulcerative colitis. Total RNAs were extracted, amplified, and applied to Affymetrix GeneChip(R) X3P Array. For the control, similar crypts from nonspecific colitis biopsies were applied. A total of 353 (4.3%) and 111 (1.4%) genes were >3 times up-, and down-regulated in ulcerative colitis. Up-regulated genes included FCGBP (Fc fragment of IgG binding protein), cyclophilin A, chemokine (C-X-C motif) ligand 3, and genes associated with lipid metabolism. Down-regulated genes included APOA4 (apolipoprotein A-IV), cylindromatosis, BCL2-like 10, claudin 8, and numerous transcriptional regulators. FCGBP and APOA4 have been implicated in ulcerative colitis previously. Our data show differential expression in the crypt epithelia of ulcerative colitis before active inflammation is initiated, suggesting primary crypt abnormalities that might be implicated in the pathogenesis of ulcerative colitis. Show less

To detect the disease-causing gene mutation of hypertrophic cardiomyopathy (HCM) in a Chinese family and to analyze the correlation of the genotype and the phenotype. One family affected with HCM was studied. The clinical data including symptom, physical examination, echocardiography and electrocardiography were collected. The full encoding exons and flanking sequences of beta-myosin heavy chain gene (MYH7) and cardiac myosin-binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced. A G8887A mutation, which is an acceptor splicing site of intron 15 (IVS15-1G > A) in MYBPC3 (gi: Y10129) was identified in 6 out of 11 family members. Three mutation carriers developed HCM at 48 - 75 years old with mild chest pain, chest distress and asymmetric septal hypertrophy (13 - 14 mm) and remaining mutation carriers are free of HCM. No mutation was identified in MYH7 gene. HCM caused by the IVS15-1G > A mutation is a benign phenotype. It is helpful to screen MYBPC3 gene mutation in late-onset HCM patients with mild symptoms. Show less

Type 2 diabetes mellitus (DM) is associated with significant abnormalities of lipoprotein metabolism and coronary heart disease (CHD). The most commonly recognized lipid abnormality in type 2 DM is hypertriglyceridemia, which is known to be an independent risk factor for CHD in diabetics. The -1131T-->C polymorphism found in the newly identified apolipoprotein A5 ( APOA5 ) gene has been found to be associated with elevated plasma triglyceride (TG) concentrations in different racial groups. In this study, DNA samples from 155 control subjects, 172 type 2 diabetics and 113 type 2 DM patients with CHD were analyzed to examine the influence of APOA5 1131T-->C polymorphism on plasma lipids and the susceptibility to CHD in type 2 diabetics. The frequency of the APOA5 -1131C allele in the DM+CHD group was significantly higher than that of control subjects (37.2% vs. 27.7%, p=0.021). The distribution of the APOA5 -1131T-->C genotypes (TT, TC and CC) was 36.3%, 53.1% and 10.6% in type 2 DM patients with CHD, and 53.6%, 37.4% and 9.0% in controls, respectively (p=0.018). The frequencies of alleles and genotypes in type 2 diabetics were not significant compared to controls. In controls, plasma TG concentrations in subjects with the TT genotype were significantly lower than in those with TC/CC (0.92, 1.28 and 1.35 mmol/L for TT, TC and CC, respectively; p = 0.003 by ANOVA). These data suggest that the APOA5 -1131T-->C polymorphism might play a role in elevated plasma TG levels in type 2 diabetic patients in the Chinese population. Show less

The Delta-Notch signaling pathway is an evolutionarily conserved intercellular signaling mechanism essential for cell fate specification. Mind bomb 1 (Mib1) has been identified as a ubiquitin ligase that promotes the endocytosis of Delta. We now report that mice lacking Mib1 die prior to embryonic day 11.5, with pan-Notch defects in somitogenesis, neurogenesis, vasculogenesis and cardiogenesis. The Mib1-/- embryos exhibit reduced expression of Notch target genes Hes5, Hey1, Hey2 and Heyl, with the loss of N1icd generation. Interestingly, in the Mib1-/- mutants, Dll1 accumulated in the plasma membrane, while it was localized in the cytoplasm near the nucleus in the wild types, indicating that Mib1 is essential for the endocytosis of Notch ligand. In accordance with the pan-Notch defects in Mib1-/- embryos, Mib1 interacts with and regulates all of the Notch ligands, jagged 1 and jagged 2, as well as Dll1, Dll3 and Dll4. Our results show that Mib1 is an essential regulator, but not a potentiator, for generating functional Notch ligands to activate Notch signaling. Show less

There are more than 1 million patients with hypertrophic cardiomyopathy (HCM) in China, but the genetic basis is presently unknown. We investigated 100 independent patients with HCM (proband 51, sporadic 49) by sequencing the three most frequent HCM-causing genes (MYH7, MYBPC3, TNNT2). Thirty-four patients (34%) carried 25 types of mutations in the selected genes, most (14/25) were newly identified. MYH7 and MYBPC3 accounted for 41% and 18% of the familial HCM, respectively. TNNT2 mutations only caused 2% of the familial HCM. These results suggested that MYH7 and MYBPC3 were the predominant genes responsible for HCM, and TNNT2 mutation less proportionally contributed to Chinese HCM. MYH7 mutations caused HCM at younger age, more frequent syncope and ECG abnormalities compared with MYBPC3 mutations. The patients carrying R663C, Q734P, E930K in MYH7 and R130C in TNNT2 expressed malignant phenotype. R403Q in MYH7, the most common hot and malignant mutation in Caucasians, was not identified in Chinese. We confirmed the diversity of mutation profile in different populations and suggest that a global registry of HCM mutations and their phenotypes is necessary to correlate genotype with phenotype. Show less

Apolipoproteins AI/CIII/AIV play important roles in the metabolism of triglycerides (TG) and high-density lipoprotein (HDL) cholesterol. However, whether genetic variations in the APOA1/C3/A4 gene cluster are associated with the risk of myocardial infarction (MI) remains uncertain and prospective data are sparse. In a prospective nested case-control study of 385 incident cases of MI and 373 age- and smoking-matched controls from the Physicians' Health Study, we examined the relationship between 2 common single nucleotide polymorphisms (APOA1 XmnI and APOC3 SstI) in the APOA1/C3/A4 gene cluster and haplotypes defined by these SNPs and risk of incident MI. No significant differences in allele or genotype frequency for the APOA1 XmnI and APOC3 SstI polymorphisms were detected between cases and controls. After adjusting for non-lipid coronary risk factors, the relative risks for incident MI were 1.00 (95% CI 0.68-1.47) for men carrying the X2 allele compared with those homozygous for the X1 allele in the APOA1 XmnI site and 1.07 (95% CI 0.69-1.64) for men carrying the S2 versus those homozygous for the S1 allele in the APOC3 SstI site. Moreover, we did not observe any effect modification by HDL or TG levels for the associations of these APOA1 and APOC3 genotypes with MI risk. There were significant differences in TG levels among men carrying different haplotypes (P=0.01) and men carrying the X1-S2 haplotype had higher levels of TG than those carrying the X2-S1 haplotype (202 mg/dl versus 157 mg/dl, P=0.03); however, haplotype frequencies defined by these two polymorphisms did not differ significantly between cases and controls. In this prospective study of apparently healthy middle-aged US men, carriers of the X1-S2 haplotype in the APOA1 XmnI and APOC3 SstI variants across the APOA1/C3/A4 gene cluster had higher TG levels, but there was no evidence for significant associations between these two common variants or haplotypes defined by them and risk of incident MI in this cohort. Show less

Bardet-Biedl syndrome (BBS) is a heterogeneous multisystemic disorder characterized primarily by five cardinal features of retinal degeneration, obesity, polydactyly, hypogenitalism and mental retardation. To date, six distinct BBS loci that have been identified on different chromosomes. BBS4 gene is mapped to 15q22.2-23, which when mutated can cause BBS4. Its protein shows strong homology to O-linked N-acetylglucosamine (O-GlcNAc) transferase. Here we report a splice variant of BBS4, which is 2556 bp in length and has an open reading frame coding a predicted 527 amino-acids protein. RT-PCR shows that the cDNA is widely expressed while it has higher expression levels in pancreas, liver and prostate. Show less

A polysaccharide from the water extract of cultured Cordyceps militaris was isolated through ethanol precipitation, deproteination and gel-filtration chromatography. Their molecular weight was determined using gel-filtration chromatography. The structure of polysaccharide CPS-1 was elucidated by sugar analysis, Smith degradation, IR and 13C-NMR spectroscopy. CPS-1 was shown to possess a significant antiinflammatory activity and suppressed the humoral immunity in mice but had no significant effects on the cellular immunity and the non-specific immunity. Show less

Interactions between Wnts, Fgfs and Tbx genes are involved in limb initiation and the same gene families have been implicated in mammary gland development. Here we explore how these genes act together in mammary gland initiation. We compared expression of Tbx3, the gene associated with the human condition ulnar-mammary syndrome, expression of the gene encoding the dual-specificity MAPK phosphatase Pyst1/MKP3, which is an early response to FGFR1 signalling (as judged by sensitivity to the SU5402 inhibitor), and expression of Lef1, encoding a transcription factor mediating Wnt signalling and the earliest gene so far known to be expressed in mammary gland development. We found that Tbx3 is expressed earlier than Lef1 and that Pyst1 is also expressed early but only transiently. Patterns of expression of Tbx3, Pyst1 and Lef1 in different glands suggest that the order of mammary gland initiation is 3, 4, 1, 2 and 5. Consistent with expression of Pyst1 in the mammary gland, we detected expression of Fgfr1b, Fgf8 and Fgf9 in both surface ectoderm and mammary bud epithelium, and Fgf4 and Fgf17 in mammary bud epithelium. Beads soaked in FGF-8 applied to the flank of mouse embryos, at a stage just prior to mammary bud initiation, induce expression of Pyst1 and Lef1 and maintain Tbx3 expression in flank tissue surrounding the bead. Grafting beads soaked in the FGFR1 inhibitor, SU5402, abolishes Tbx3, Pyst1 and Lef1 expression, supporting the idea that FGFR1 signalling is required for early mammary gland initiation. We also showed that blocking Wnt signalling abolishes Tbx3 expression but not Pyst1 expression. These data, taken together with previous findings, suggest a model in which Tbx3 expression is induced and maintained in early gland initiation by both Wnt and Fgf signalling through FGFR1. Show less

The constitutive activation of signal transducer and activator of transcription 3 (Stat3) is frequently detected in breast cancer cell lines but not in normal breast epithelial cells. Stat3 has been classified as an oncogene, because constitutively active Stat3 can mediate oncogenic transformation in cultured cells and tumor formation in nude mice. Since Stat3 appears to play an important role in breast cancer, it is of interest to investigate Stat3-regulated genes and elucidate Stat3-mediated oncogenesis. In this study, we investigated the Stat3-regulated genes in human breast epithelial cells. Upon overexpression of Stat3-C, a constitutively active Stat3 form, in nonmalignant telomerase immortalized breast (TERT) cells, the total mRNA was extracted and subjected to Affymetrix microarray analysis. Our results showed that mitogen-activated protein kinase kinase 5 (MEK5) was markedly induced (more than 22-fold increase, P<0.001) by Stat3-C expression. RT-PCR result also demonstrated that MEK5 mRNA was significantly induced by Stat3-C in TERT cells. The upregulation of MEK5 by Stat3-C was further confirmed by Western blot in MCF10A breast epithelial cells. Furthermore, in MDA-MB-435s breast carcinoma cells, which express high levels of activated Stat3 and MEK5, MEK5 protein was significantly reduced by using Stat3 short interfering RNA. The reduction of MEK5 was consistent with Stat3 knockdown in this breast carcinoma cell line. We also investigated MEK5 expression in different breast carcinoma cell lines and breast cancer tissues using tissue array analysis. Compared with nonmalignant breast epithelial cells or normal tissues without constitutively active Stat3 signaling, MEK5 protein levels are remarkably higher in breast carcinoma cell lines and cancer tissues with constitutively activated Stat3. Taken together, our findings suggest that constitutively active Stat3 upregulates MEK5 in the breast epithelial cells. MEK5 may be one of the Stat3-regulated genes and plays its essential roles in oncogenesis mediated by aberrantly activated Stat3 signaling in breast carcinomatosis and malignancies. Show less

Clozapine and its two major metabolites, N-desmethylclozapine and clozapine N-oxide were quantified using a high-performance liquid chromatographic method with UV detection in dog plasma following a single dose of clozapine. The analysis was performed on a 5-micrometer Hypersil CN (CPS-1; 250x4.6 mm) column. The mobile phase consisted of acetonitrile-water-1 M ammonium acetate (50:49:1, v/v/v), which was adjusted to pH 5.0 with acetic acid. The detection wavelength was 254 nm. A liquid-liquid extraction technique was used to extract clozapine and its metabolites from dog plasma. The recovery rates for clozapine, N-desmethylclozapine, and the internal standard (I.S.) were close to 100% using this method. The recovery rate for clozapine N-oxide (62-66%) was lower as expected because it is more polar. The quantitation limits for clozapine, clozapine N-oxide, and N-desmethylclozapine were 0.11, 0.05 and 0.05 microM, respectively. Intra-day reproducibility for concentrations of 0.1, 1.0 and 5.0 microM were 10.0, 4.4 and 4.2%, respectively, for N-oxide; 11.2, 4.3 and 4.9%, respectively, for N-desmethylclozapine; and 10.8, 2.2 and 4.9%, respectively, for clozapine. Inter-day reproducibility was <15% for clozapine N-oxide, <8% for N-desmethylclozapine and <19% for clozapine. This simple method was applied to determine the plasma concentration profiles of clozapine, N-desmethylclozapine and clozapine N-oxide in dog following administration of a 10 mg/kg oral dose of clozapine. Show less

Many patients with chronic renal failure (CRF) requiring hemodialysis present with hypertriglyceridemia (HTG). But the exact cause of HTG in CRF is still unknown. Genetic variation of the apo AI-CIII-AIV gene cluster was reported to be associated with primary HTG, atherosclerosis and coronary artery disease. This study was designed to evaluate the association between the restriction fragment length polymorphism (RFLP) of the apo AI-CIII-AIV gene cluster and HTG in patients with CRF undergoing hemodialysis. Genetic variations of the apo AI-CIII-AIV gene cluster were analysed in peripheral leukocyte samples from 59 patients with CRF undergoing hemodialysis: 17 patients with HTG (CRF-HTG) and 42 patients without HTG (CRF-NTG). The RFLP was achieved through the digestion of PCR products by two restriction enzymes, SstI and MspI. The frequency of SstI minor allele (S2) in CRF-HTG was 0.44, which was significantly higher than that in CRF-NTG (0.17). Frequencies of MspI minor allele (M2) in CRF-HTG and CRF-NTG were not significantly different (0.5 vs 0.32) (p=0.07). Frequencies of S2-M2 genotype were 0.65 in CRF-HTG, and 0.27 in CRF-NTG (p<0.005). These data indicate that genetic variation of the apo AI-CIII-AIV gene cluster may serve as one of the causes of HTG in CRF. Show less

To investigate further the genetic basis of hereditary multiple exostoses (EXT) and provide useful information for gene diagnosis of the disease. Polymerase chain reaction-single strand conformation polymorphism was used to examine the entire coding regions of EXT(1) gene on chromosome 8 and EXT(2) gene on chromosome 11 for mutation in thirty EXT families. Mutations were further identified by sequencing. Two frameshift mutations were identified in two unrelated EXT families. One was the deletion of one base(T) in exon 6 of the EXT(1) gene, and the other was the deletion of four bases (tgtt) in exon 2 of the EXT(2) gene. Both of the mutations resulted in a frameshift and premature termination of translation. EXT is a genetically heterogeneous bone disorder caused by the mutation of EXT tumor suppressor gene. These results could be directly applied in the genetic counseling and prenatal genetic diagnosis of EXT. Show less