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1.
The ABCB4 gene codes for a protein involved in the transport of phosphatidylcholine across the canalicular membrane of the hepatocyte. ABCB4 gene defects have been associated with progressive familial intrahepatic cholestasis type 3, intrahepatic cholestasis of pregnancy, adult biliary cirrhosis and the more recently described low phospholipid associated cholelithiasis syndrome. The present paper describes 2 probands with a long history of recurrent pancreatitis and cholelithiasis and the same heterozygous, as yet undescribed del 3683>3688 within exon 28 of the ABCB4 gene resulting in a loss of function. This report shows that ABCB4 mutations may cause acute recurrent biliary pancreatitis.  相似文献   

2.
Cholestatic liver disease (CLD) is a major cause of progressive liver damage and liver failure. Several forms of biliary cirrhosis are caused by mutations in specific genes. We sought to identify a genetic defect in a family with CLD impossible to assign to a distinct pathogenic entity. Clinical and histopathological characterization of the family members, microarray-based single-nucleotide polymorphism genotyping, and analysis of candidate genes were performed. Among six of 11 siblings severely affected by idiopathic CLD in a family from a population isolate in Transylvania, three died of cirrhosis (aged 5, 7, and 43 years) and three had adult-onset disease with small duct cholangiopathy, including ductopenia. Others were mildly affected and experienced intrahepatic cholestasis of pregnancy, miscarriages, or stillbirth. Pedigree studies revealed distant parental consanguinity. Genome-wide linkage analysis and autozygosity mapping yielded a single maximal lod-score of 3.88 on chromosome 7q21.1-7q22, excluding other genomic loci. Sequencing of ABCB4 at this locus revealed a novel missense mutation c.2362C>T (p.Arg788Trp) which cosegregated with severity of disease. Bile from a mutation homozygote showed a reduced phosphatidylcholine/bile acid ratio, consistent with reduced ABCB4 phosphatidylcholine transport activity. CONCLUSION: We show that a missense mutation in ABCB4 is a cause for ductopenic CLD in adulthood. Allelic status correlated with severity of liver disease ranging from intrahepatic cholestasis of pregnancy through fibrosis to cirrhosis and death in childhood and adulthood. Mutational analysis of ABCB4 should be generally considered in all patients with cholestatic liver disease of unknown etiology regardless of age and onset of disease.  相似文献   

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A high prevalence of gallstones has been described in patients following colectomy. The aim of this study was to examine whether lithogenicity is attributed to colectomy. In the present study, changes in gallbladder bile composition and the mechanism of gallstone formation after colectomy were examined in dogs. Ten mongrel dogs underwent restorative proctocolectomy. Seven dogs which received sham operations served as controls. Over a 12-week postoperative period, samples of gallbladder bile, formed gallstones and serum were collected and analyzed. In 7 of the 10 (70%) colectomized dogs, gallstones were found in the gallbladder, while the control dogs had no stones. Macroscopically the gallstones were similar to black pigment stones observed in humans. Chemical analysis and Fourier transform-infrared spectroscopy examination revealed that the stones were composed mainly of sodium bilirubinate and proteins, with minor amounts of calcium salts and cholesterol. Significant increases in biliary pH and concentrations of ionized calcium and unconjugated bilirubin were observed in the gallbladder bile of the colectomy group compared with that of the control group. The total bile acid and total bilirubin concentrations were significantly decreased in the colectomy group. Cholesterol crystal nucleation did not occur. The inhibitory effect of gallbladder bile on calcium carbonate precipitation in anin vitro assay system was preserved even after colectomy. In conclusion, proctocolectomy increases the concentration of unconjugated bilirubin in gallbladder bile and induces pigment gallstones which are composed mainly of sodium bilirubinate and proteins since calcium ions and cholesterol are stabilized in dogs.  相似文献   

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p53 mutation is associated with progression in follicular lymphomas   总被引:15,自引:4,他引:15  
Sander  CA; Yano  T; Clark  HM; Harris  C; Longo  DL; Jaffe  ES; Raffeld  M 《Blood》1993,82(7):1994-2004
The majority of low-grade follicular lymphomas will eventually transform to an aggressive intermediate, or high-grade lymphoma. The molecular mechanisms responsible for this transformation have not been determined. We studied serial biopsies from 34 patients with follicular lymphomas that underwent histologic transformation, for abnormalities of the p53 tumor suppressor gene by a combination of immunohistochemistry, single strand conformation polymorphism analysis (SSCP), and sequencing. We found overexpression of p53 in 10 of the 34 transformed aggressive lymphomas, 9 of which contained mutations identified by SSCP analysis and subsequent sequencing. Matched pretransformation low-grade follicular lymphoma biopsies were available for 7 of the 10 cases. None of six studied by immunohistochemistry showed overexpression of p53 and only 1 of 4 studied by SSCP/sequencing showed the presence of mutation in the pretransformation biopsy. Interestingly, an eighth p53 positive transformed lymphoma recurred with a clonally related, p53 negative low-grade lymphoma 5 years after the patient had achieved a complete remission. Immunohistochemistry also showed that several pretransformation biopsies from p53 positive transformed cases showed rare p53 positive cells and in one case we could document an increase in their number over time. Twenty-five additional low-grade follicular lymphoma biopsies were also examined. Three patients had lymphomas positive for p53 mutation. One of the three subsequently transformed within a year of the biopsy studied; the second patient had an earlier (unavailable) biopsy at a different site that showed transformed histology. The third patient was treated with ProMACE-MOPP combination chemotherapy and attained a complete remission. We conclude that (1) mutations of p53 are associated with histologic transformation in approximately 25% to 30% of follicular lymphomas and (2) p53 positive cells can be detected before histologic transformation, but do not comprise a significant percentage of the neoplastic cell population (identifiable by SSCP) until late in the disease, just before or after histologic progression. Finally, the data also suggest that p53 positive low-grade lymphomas are at risk for progression and that in this subset, aggressive therapy may be warranted.  相似文献   

9.
The pulsatile secretion patterns of GH were investigated in seven beagle bitches by collecting blood samples every 10 min for 6 h during euthyroidism and 1.5 years after induction of primary hypothyroidism. Hypothyroidism was induced by surgical removal of the thyroid gland and subsequent destruction of any remnant thyroid tissue by oral administration of sodium [(131)I]iodide. Some of the physical changes observed in the dogs with primary hypothyroidism mimicked those of acromegaly. During both euthyroidism and hypothyroidism GH was secreted in a pulsatile fashion. The mean (+/-s.e.m. ) basal plasma GH concentration was significantly higher (P=0.003) in the hypothyroid state (4.1+/-1.6 microg/l) than in the euthyroid state (1.2+/-0.4 microg/l). Likewise, the mean area under the curve (AUC) for GH above the zero-level during hypothyroidism (27.0+/-10.0 microg/lx6 h) was significantly higher (P=0.004) than that during euthyroidism (11.7+/-2.0 microg/l x 6 h). The mean AUC for GH above the baseline was significantly lower (P=0.008) during hypothyroidism (2.4+/-0.8 microg/l x 6 h) than during euthyroidism (4.5+/-1.8 microg/lx6 h), whereas there was no significant difference in GH pulse frequency. The mean plasma IGF-I level was significantly higher (P<0.01) in the hypothyroid state (169+/-45 microg/l) than in the euthyroid (97+/-15 microg/l). The results of this study demonstrate that primary hypothyroidism in dogs is associated with elevated basal GH secretion and less GH secreted in pulses. This elevated GH secretion has endocrine significance as illustrated by elevated plasma IGF-I levels and some physical changes mimicking acromegaly. It is discussed that the increased GH release in hypothyroid dogs may be the result of the absence of a response element for thyroid hormone within the canine pituitary GH gene and alterations in supra-pituitary regulation.  相似文献   

10.
Gallstones are very common. However, there is a small group of patients with low phospholipid‐associated cholelithiasis (LPAC) that is characterized by symptomatic cholelithiasis at a young age (<40 years), recurrence of biliary symptoms despite cholecystectomy and concrements or sludge in the intra‐ and extrahepatic biliary system. The LPAC syndrome is associated with mutations of the adenosine triphosphate‐binding cassette, subfamily B, member 4 (ABCB4) gene encoding the hepatobiliary phospholipid translocator multidrug resistance protein 3 (MDR3). Impairment of MDR3 leads to a reduction of biliary phosphatidyl choline levels resulting in a lithogenic and toxic bile. This causes recurrent cholelithiasis, continuous irritations of the biliary tract with cholangitis, chronic cholestasis and even biliary cirrhosis. Here we report on a family with ABCB4 deficiency and LPAC syndrome associated with a novel mutation (c.3203T>A) in the ABCB4 gene.  相似文献   

11.
The pivotal step on the mitochondrial pathway to apoptosis is permeabilization of the mitochondrial outer membrane (MOM) by oligomers of the B-cell lymphoma-2 (Bcl-2) family members Bak or Bax. However, how they disrupt MOM integrity is unknown. A longstanding model is that activated Bak and Bax insert two α-helices, α5 and α6, as a hairpin across the MOM, but recent insights on the oligomer structures question this model. We have clarified how these helices contribute to MOM perforation by determining that, in the oligomers, Bak α5 (like Bax α5) remains part of the protein core and that a membrane-impermeable cysteine reagent can label cysteines placed at many positions in α5 and α6 of both Bak and Bax. The results are inconsistent with the hairpin insertion model but support an in-plane model in which α5 and α6 collapse onto the membrane and insert shallowly to drive formation of proteolipidic pores.Commitment of cells to apoptosis is determined primarily by interactions within the B-cell lymphoma-2 (Bcl-2) protein family on the mitochondrial outer membrane (MOM) (14). The proapoptotic members Bcl-2 antagonist/killer (Bak) and Bcl-2–associated X protein (Bax) mediate the pivotal step of MOM permeabilization, which releases proteins, such as cytochrome c, that promote the proteolytic demolition by caspases. Two other Bcl-2 subfamilies tightly control Bak and Bax activation. Their activation is promoted by the Bcl-2 homology domain 3 (BH3)-only proteins, such as BH3-interacting domain death agonist (Bid), the truncated form of which (tBid) can directly bind both. Conversely, prosurvival family members can bind and inhibit activated Bak and Bax, as well as the BH3-only proteins.Like their prosurvival relatives, Bak and Bax in healthy cells are globular monomers, comprising similar helical bundles with a hydrophobic α-helix (α5) surrounded by amphipathic helices (5, 6). Their C-terminal helix (α9) is a hydrophobic transmembrane (TM) domain that anchors them in the MOM. In healthy cells Bak is already anchored there, presumably solely by α9, whereas Bax is primarily cytosolic (5), accumulating at the MOM after an apoptotic signal and inserting its α9. Other major conformational changes in both Bak and Bax, reviewed in ref 4, include exposure of their BH3 (α2) and its reburial within the surface groove of another activated Bak or Bax molecule (710). These novel “symmetric” homo-dimers can multimerize via association of α6 helices (8, 11, 12).Although oligomeric Bak and Bax are highly implicated in MOM permeabilization, how they interact with the membrane to form pores remains a mystery. The first structure of a Bcl-2 family member, the prosurvival protein Bcl-xL (13), and later those of Bax (5) and Bak (6), provided a tantalizing clue: similarities with the pore-forming domains of bacterial toxins, such as diphtheria toxin or colicin A. To form pores, these toxins are thought to insert their two hydrophobic core helices as a hairpin across the membrane (14), suggesting that the central helices of Bak and Bax (α5 and α6) might penetrate the MOM similarly (reviewed in refs 3, 15, and 16). Consistent with this hairpin insertion model, α5 and α6 peptides can permeabilize membranes (1719). More pertinently, Bax α5 and α6 were reported to insert into and span the MOM as a hairpin before oligomerization (20).This longstanding model, however, does not fit well with recent evidence on the structure of Bak and Bax oligomers, as recently reviewed (2, 4). Analysis of Bak oligomers in liposomes by electron paramagnetic resonance (EPR) suggests that α6 inserts only shallowly in the lipid bilayer (21). Additionaly, the first 3D structures of activated forms of Bax (10) suggest that, early in its activation, α5 and α6 separate. Moreover, a Bax core domain containing only helices α2 to α5 generated a BH3:groove symmetric dimer in which two α4 and two α5 helices form an aromatic face that might sit on the bilayer (10). These findings fit better with an “in-plane model” in which only α9 is a TM domain and other helices (including α5 and α6) insert only shallowly into the bilayer.The nature of the apoptotic pores remains uncertain. Some findings favor a proteinaceous pore (22), but studies with model membranes suggest that Bax oligomers can perturb the bilayer and produce lipidic pores (i.e., pores not bounded entirely by protein) (2326).These important unresolved questions about the pivotal event in apoptosis prompted us to explore the membrane topology of Bak, before, during, and after an apoptotic signal, and to reinvestigate that of Bax. In accord with recent Bax structures (10) and recent EPR studies on Bak (21, 27), the results show that neither oligomeric Bak nor Bax inserts an α5–α6 hairpin across the MOM. We propose instead that the α5 and α6 helices lie in the bilayer plane and disrupt membrane integrity by imposing tension and curvature to the membrane that provoke its permeabilization.  相似文献   

12.
BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) is characterised by troublesome maternal pruritus, raised serum bile acid levels and increased fetal risk. Mutations of the ABCB4 gene encoding the hepatobiliary phospholipid transporter have been identified in a small proportion of patients with cholestasis of pregnancy. In a recent prospective study on 693 patients with cholestasis of pregnancy, a cut-off level for serum bile acid (> or =40 micromol/l) was determined for increased risk of fetal complications. OBJECTIVES: To investigate whether common combinations of polymorphic alleles (haplotypes) of the genes encoding the hepatobiliary ATP-binding cassette (ABC) transporters for phospholipids (ABCB4) and bile acids (ABCB11) were associated with this severe form of cholestasis of pregnancy. METHODS: For genetic analysis, 52 women with bile acid levels > or =40 micromol/l (called cases) and 52 unaffected women (called controls) matched for age, parity and geographical residence were studied. Gene variants tagging common ABCB4 and ABCB11 haplotypes were genotyped and haplotype distributions were compared between cases and controls by permutation testing. RESULTS: In contrast with ABCB11 haplotypes, ABCB4 haplotypes differed between the two groups (p = 0.019), showing that the severe form of cholestasis of pregnancy is associated with the ABCB4 gene variants. Specifically, haplotype ABCB4_5 occurred more often in cases, whereas haplotypes ABCB4_3 and ABCB4_7 were more common in controls. These associations were reflected by different frequencies of at-risk alleles of the two tagging polymorphisms (c.711A: odds ratio (OR) 2.27, p = 0.04; deletion intron 5: OR 14.68, p = 0.012). CONCLUSION: Variants of ABCB4 represent genetic risk factors for the severe form of ICP in Sweden.  相似文献   

13.
Hemochromatosis is a common disorder characterized by excess iron absorption and accumulation of iron in tissues. Usually hemochromatosis is inherited in an autosomal recessive pattern and is caused by mutations in the HFE gene. Less common non-HFE-related forms of hemochromatosis have been reported and are caused by mutations in the transferrin receptor 2 gene and in a gene localized to chromosome 1q. Autosomal dominant forms of hemochromatosis have also been described. Recently, 2 mutations in the ferroportin1 gene, which encodes the iron transport protein ferroportin1, have been implicated in families with autosomal dominant hemochromatosis from the Netherlands and Italy. We report the finding of a novel mutation (V162del) in ferroportin1 in an Australian family with autosomal dominant hemochromatosis. We propose that this mutation disrupts the function of the ferroportin1 protein, leading to impaired iron homeostasis and iron overload.  相似文献   

14.

Background

Two members of the Ras/Raf signaling pathway, KRAS and B-raf, are suspected to be involved in the stepwise progression of colorectal cancer (CRC) tumorigenesis.

Objective

We compared the KRAS and BRAF mutation status of CRC patients with their clinicopathological characteristics and examined the effect of mutation status on survival rates.

Methods

DNA was extracted from 164 samples, and the mutation statuses of KRAS and BRAF were assessed using peptide PNA clamp real-time PCR method. The presences of mutation were compared with clinicopathological factors and 5-year survival rate.

Results

Among the 164 CRC cases, KRAS mutation as detected in 71 cases (43.3 %), respectively, with no relationship with clinicopathological factors of the patients. On Kaplan–Meier survival analysis, KRAS mutation was not significantly associated with survival (p = 0.971). BRAF mutation was detected in 26 cases (15.9 %) and not associated with clinicopathological factors of the patients. However, the 5-year survival rate of BRAF mutations was significantly decreased (p = 0.02).

Conclusions

The presence of KRAS mutation did not correlate with the various clinicopathological factors of CRC patients or the survival rate. However, the survival rate was reduced in BRAF-mutated CRC patients. Therefore, BRAF mutation could be an important prognostic factor in CRC patients.  相似文献   

15.
Canine hepacivirus (CHV) has recently been identified in liver and respiratory tract samples from dogs, and comparative phylogenetic analysis has confirmed it to be the closest genetic relative of hepatitis C virus (HCV) described to date. CHV offers great potential as a model system for HCV, but only if the underlying processes of infection and pathogenesis are similar for both viruses. However, it is not yet clear if CHV is hepatotrophic. Canine chronic hepatitis (CH) is a common and usually idiopathic disease that shares similar histological features to that of HCV infection of humans. To date, no study has attempted to determine whether CHV is involved in the aetiology of liver disease in dogs. We employed two nested PCR assays, using primers targeting regions of the helicase domain of CHV NS3, to identify viral nucleic acids in liver samples from 100 dogs with CH of unknown cause in the UK. We also used a sensitive luciferase immunoprecipitation system (LIPS) assay to screen serum samples from these dogs for the presence of anti‐CHV antibodies. Surprisingly, there was no evidence of exposure to, or a carrier state of, CHV in this large cohort, suggesting that the virus is not associated with CH in UK dogs. Future work, including transmission studies, is required to understand the pathogenesis of CHV in canids before it can be proposed as a surrogate model for HCV‐induced liver disease in man.  相似文献   

16.
BACKGROUND: Endoscopic stent insertion into the gallbladder entails placement of a double-pigtail polyethylene stent between the gallbladder and the duodenum at ERCP. This procedure may be an effective temporary measure in patients with severe comorbid conditions, especially end-stage liver disease, that subsequently allows more definitive therapy, including liver transplantation. METHODS: The records for 29 patients who underwent attempted endoscopic gallbladder stent insertion between May 1999 and May 2004 were reviewed retrospectively. RESULTS: Mean patient age was 47 years; 86% of the patients were listed for liver transplantation, with a mean model for end-stage liver disease score of 15; 72% had Child's class B cirrhosis. Indications for gallbladder stent placement included recurrent biliary colic (69%), acute cholecystitis (17%), acalculous cholecystitis (7%), and gallstone pancreatitis (7%). Of the 29 patients who underwent ERCP, stent placement was successful in 26 (90%). Median follow-up was 9.4 months (range 0.1-40.5 months). Of those who had a stent placed, 6 (22%) subsequently underwent liver transplantation and another 15 (56%) were alive, most awaiting liver transplantation. Only 3 patients had late a complication or recurrence of biliary symptoms after stent placement. CONCLUSIONS: Endoscopic stent placement in the gallbladder is a safe and an effective palliative treatment for patients with symptoms caused by gallbladder disease who are poor surgical candidates.  相似文献   

17.
Gorska MM  Alam R 《Blood》2012,119(6):1399-1406
Idiopathic CD4 lymphopenia (ICL) is an immunodeficiency disorder of unclear etiology. Here we describe a heterozygous dominant-negative missense mutation (codon 22 GGC→GTC; V22G) of the signaling adaptor protein Uncoordinated 119 (Unc119) in an ICL patient. The patient is a 32-year-old female with < 300 CD4 T cells/μL and with a history of recurrent sinusitis/otitis media, frequent episodes of shingles, a widespread fungal nail infection, fungal dermatitis, oral herpetic lesions, and bronchiolitis obliterans organizing pneumonia after 2 episodes of bacterial pneumonia. The patient's cells have reduced response to TCR stimulation, with impairment in both localization and enzymatic activation of the lymphocyte-specific kinase (Lck) resulting in decreased cell proliferation. Transduction of the mutant Unc119 but not wild-type Unc119 into normal T cells reproduces the signaling and proliferation defects. The mutation disrupts the Unc119-Lck interaction which is normally needed for stimulation of the Lck catalytic activity by TCR. The mutant protein also causes mislocalization of Lck to Rab11(+) perinuclear endosomes. The mutation is not present in 2 other patients with ICL, patients with secondary CD4 lymphopenia or 60 healthy subjects. The V22G mutation of Unc119 represents a novel genetic defect in ICL.  相似文献   

18.
The idea that memory is encoded by means of synaptic growth is not new. However, this idea has been difficult to demonstrate in the mammalian brain because of both the complexity of mammalian behavior and the neural circuitry by which it is supported. Here we examine how eyeblink classical conditioning affects synapse number within the cerebellum; the brain region essential for long-term retention of the conditioned response. Results showed eyeblink-conditioned rats to have significantly more synapses per neuron within the cerebellar interpositus nucleus than both explicitly unpaired and untrained controls. Further analysis showed that the increase was caused by the addition of excitatory rather than inhibitory synapses. Thus, development of the conditioned eyeblink response is associated with a strengthening of inputs from precerebellar nuclei rather than from cerebellar cortex. These results demonstrate that the modifications of specific neural pathways by means of synaptogenesis contributes to formation of a specific memory within the mammalian brain.  相似文献   

19.
BackgroundImatinib mesylate (IM) is a selective tyrosine kinase inhibitor used for treating chronic myeloid leukemia (CML). IM has high efficacy, however some individuals develop a resistance due to impaired bioavailability. Polymorphisms in genes encoding membrane transporters such as ABCB1 have been associated with differences in protein expression and function that influence the response to several drugs.AimTo investigate the relationship of ABCB1 polymorphisms with markers of response to IM in patients with CML.MethodsOne hundred eighteen CML patients initially treated with a standard dose of IM (400 mg/day) for 18 months were selected at two health centers in Sao Paulo City, Brazil. The response criteria were based on the European LeukemiaNet recommendations. ABCB1 polymorphisms c.1236C > T (rs1128503), c.3435C > T (rs1045642) and c.2677G > T/A (rs2032582) were evaluated by PCR-RFLP.ResultsABCB1 polymorphisms were not related with a risk for CML in this sample population (p < 0.05). In the CML group, frequencies of ABCB1 SNPs were similar between responder and non-responder patients (p > 0.05). In the responder group, the frequency of ABCB11236CT/2677GT/3435CT haplotype was higher in patients with major molecular response (MMR) (51.7%) than in patients without MMR (8.3%, p = 0.010). Furthermore, carriers of this haplotype had increased the probability of reaching the MMR compared with the non-carriers (OR: 11.8; 95% CI: 1.43–97.3, p = 0.022).ConclusionsThe ABCB1 1236CT/2677GT/3435CT haplotype is positively associated with the major molecular response to IM in CML patients.  相似文献   

20.
OBJECTIVE: Leiomyoma and hyperprolactinaemia are both progesterone-dependent diseases. Hormone-related genes, such as the progesterone receptor (PGR), might be involved in their pathogenesis. DESIGN AND MEASUREMENTS: Subjects were divided into three groups: (i) leiomyoma (n = 120); (ii) hyperprolactinaemia (n = 101); (iii) normal controls (n = 140). We investigated the Alu (306-bp DNA) insertion in intron G of the PGR gene in all individuals. PGR gene polymorphisms [T1 (wild-type); T2 (PROGINS, with Alu insertion)] were determined by PCR and electrophoresis. Genotype and allele frequencies of the PROGINS in each group were detected and compared. RESULTS: We observed no significant difference of the PGR*T1/T2 genotypes and allele frequencies between leiomyoma and other two groups. The proportions of T1 homozygote/heterozygote/T2 homozygote in each group were (i) 90/8.3/1.7%; (ii) 84.2/9.9/5.9%; (iii) 92.9/6.4/0.7%. In contrast, a higher percentage of T2-related genotype and allele were noted in hyperprolactinaemic women compared to other two groups. The proportions of T1/T2 alleles in each group were: (i) 94.2/5.8%; (ii) 89.1/10.9%; (iii) 96.1/3.9%. CONCLUSIONS: The PROGIN*T2-related genotype and allele are related to a higher susceptibility to hyperprolactinaemia. The PROGINS polymorphism is not associated with leiomyoma development.  相似文献   

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