Agonist-dependent repression mediated by mutant estrogen receptor alpha that lacks the activation function 2 core domain

Nuclear receptor corepressor (N-CoR) and silencing mediator of retinoid and thyroid hormone receptors (SMRT) form heterogeneous complexes with various histone deacetylases (HDACs). In this report, we found that ER alpha-Delta AF2, a mutant estrogen receptor alpha (ER alpha) deleted for the C-terminal activation function 2 (AF2) core domain, directs estradiol (E(2))-dependent repression and impairs E(2)-induced transactivation by wild type ER alpha. This repression required coexpressed BRG1 in SW-13 cells that lack BRG1, the ATPase constituent of the chromatin-remodeling SWI.SNF complex, and was abolished by HDAC inhibitor trichostatin A. We further demonstrated that ER alpha-Delta AF2 constitutively associates with SMRT but binds DNA in an E(2)-dependent manner in vivo. These results suggest that ER alpha-Delta AF2 and similar mutant receptors recently found associated with certain tumors may actively perturb the normal E(2) signaling via SWI/SNF, N-CoR/SMRT, and HDAC.

Retinoid-dependent antagonism of serum response factor transactivation mediated by transcriptional coactivator proteins

Transcriptional coactivators SRC-1 and p300 specifically interact with liganded-nuclear receptors and also modulate other transcription factors, including serum response factor (SRF). Here, we report that retinoids repress transactivation by SRF and specific interactions exist between the DNA binding domains of SRF and retinoic acid and retinoid X receptors. We further demonstrate that the repression may involve retinoid-dependent competition for a limiting amount of SRC-1 and p300 between SRF and retinoid receptors. We propose that the well-defined anti-proliferative action of retinoids could, at least in part, result from this novel transrepressive action on the mitogenic transcription factor SRF.

Effects of 6-arylamino-5,8-quinolinediones and 6-chloro-7-arylamino-5,8-isoquinolinediones on NAD(P)H: quinone oxidoreductase (NQO1) activity and their cytotoxic potential

Synthesized 6-arylamino-5,8-quinolinediones 4a-4j and 6-chloro-7-arylamino-5,8-isoquinolinediones 5a-5g were evaluated for effects on NAD(P)H: quinone oxidoreductase (NQO1) activity with the cytosolic fractions derived from cultured human lung cancer cells and their cytotoxicity in cultured several human solid cancer cell lines. The 5,8-quinolinediones 4 and 5,8-isoquinolinediones 5 affected the reduction potential by NQO1 activity and showed a potent cytotoxic activity against human cancer cell lines. The tested compounds 4a, 5c, 5f, and 5g were considered as more potent cytotoxic agents. The compounds 4d, 5b, 5c, 5e and 5g were comparable modulators of NQO1 activity.

Resveratrol analog, 3,5,2',4'-tetramethoxy-trans-stilbene, potentiates the inhibition of cell growth and induces apoptosis in human cancer cells

Resveratrol, a trihydroxystilbene found in grapes and several plants, has been shown to be active in inhibiting multistage carcinogenic process. Using resveratrol as the prototype, we synthesized several analogs and evaluated their growth inhibitory effect using cultured human cancer cells. In the present report we show that one of the resveratrol analogs, 3, 5,2',4'-tetramethoxy-trans-stilbene, potentiated the inhibition of cancer cell growth. Prompted by the strong growth inhibitory activity of the compound (IC50; 0.8 microg/ml) compared to resveratrol (IC50; 18.7 microg/ml) in cultured human colon cancer cells (Col2), we performed an action mechanism study using the compound. The compound induced the accumulation of cellular DNA contents in the sub-G0 phase DNA contents of the cell cycle by in a time-dependent manner. The morphological changes were also consistent with an apoptotic process. This result indicated that the compound induced apoptosis of cancer cells, and may be a candidate for use in the development of potential cancer chemotherapeutic or cancer chemopreventive agents.

The wound-healing effect of a glycoprotein fraction isolated from aloe vera

BACKGROUND

Aloe vera has been used as a family medicine for promoting wound healing, but it is not known which component of the plant is effective for this purpose.

OBJECTIVES

To isolate and characterize the component effective in wound healing.

METHODS

Chromatography, electrophoresis and spectroscopic methods were used. The cell-proliferation activity of each component isolated was measured by a [3H]thymidine uptake assay. The cell-proliferation activity of the effective component was tested on a three-dimensional raft culture (cell culture technique by which artificial epidermis is made from keratinocytes). The effect of the active component on cell migration and wound healing was observed on a monolayer of human keratinocytes and in hairless mice.

RESULTS

A glycoprotein fraction was isolated and named G1G1M1DI2. It showed a single band on sodium dodecyl sulphate-polyacrylamide gel electrophoresis, with an apparent molecular weight of about 5.5 kDa. It exhibited significant [3H]thymidine uptake in squamous cell carcinoma cells. The effect of G1G1M1DI2 on cell migration was confirmed by accelerated wound healing on a monolayer of human keratinocytes. When this fraction was tested on a raft culture, it stimulated the formation of epidermal tissue. Furthermore, proliferation markers (epidermal growth factor receptor, fibronectin receptor, fibronectin, keratin 5/14 and keratin 1/10) were markedly expressed at the immunohistochemical level. The glycoprotein fraction enhanced wound healing in hairless mice by day 8 after injury, with significant cell proliferation.

CONCLUSIONS

It is considered that this glycoprotein fraction is involved in the wound-healing effect of aloe vera via cell proliferation and migration.

Sesquiterpenoids from the rhizome of Curcuma zedoaria

In the course of searching for biologically active sesquiterpenoids from Curcuma genus, two sesquiterpenoids were isolated from the rhizome of Curcuma zedoaria (Zingiberaceae). Their structures were identified as ar-turmerone (1) and beta-turmerone (2). The structure elucidation of compounds 1 and 2 was carried out by comparison of their physical and spectral data with previously reported values.

The orphan nuclear receptor small heterodimer partner as a novel coregulator of nuclear factor-kappa b in oxidized low density lipoprotein-treated macrophage cell line RAW 264.7

Small heterodimer partner (SHP), specifically expressed in liver and a limited number of other tissues, is an unusual orphan nuclear receptor that lacks the conventional DNA binding domain. In this work, we found that SHP expression is abundant in murine macrophage cell line RAW 264.7 but was suppressed by oxidized low density lipoprotein (oxLDL) and its constituent 13-hydroxyoctadecadienoic acid, a ligand for peroxisome proliferator-activated receptor gamma. Furthermore, SHP acted as a transcription coactivator of nuclear factor-kappa B (NF kappa B) and was essential for the previously described NF kappa B transactivation by palmitoyl lysophosphatidylcholine, one of the oxLDL constituents. Accordingly NF kappa B, which was transcriptionally active in the beginning, became progressively inert in oxLDL-treated RAW 264.7 cells as oxLDL decreased the SHP expression. Thus, SHP appears to be an important modulatory component to regulate the transcriptional activities of NF kappa B in oxLDL-treated, resting macrophage cells.

Incomplete pancreas divisum: is it merely a normal anatomic variant without clinical implications?

BACKGROUND AND STUDY AIMS

Incomplete pancreas divisum (PD) has been generally regarded as merely a normal anatomic variant, without clinical implications. This study compares the prevalence, symptom occurrence rate, clinical presentation, and outcomes of endoscopic treatment in patients with incomplete PD and those with complete PD.

PATIENTS AND METHODS

The study population consisted of 56 patients (27 with complete PD and 29 with incomplete PD), identified from 4473 newly performed endoscopic retrograde cholangiopancreatography examinations. Endoscopic treatment (minor papilla sphincterotomy with stents or nasopancreatic drainage tube insertion) was attempted in 25 symptomatic patients with PD, which was suspected to be causing the associated pancreatic diseases: acute recurrent pancreatitis (ARP) (n = 13; five patients with complete PD and eight with incomplete PD); chronic pancreatitis (CP) (n = 10: five patients with complete PD and five with incomplete PD); and pancreatic-type pain (PP) (n = 2; one patient with complete PD and one with incomplete PD). The mean follow-up period was 17 months (range 9 - 49 months).

RESULTS

In 12 of the 27 patients with complete PD--six with ARP, five with CP, and one with PP--it was suspected that PD was the cause of pancreatic disease. Ten of the 11 symptomatic patients with complete PD underwent successful endoscopic treatment (five with endoscopic minor papilla sphincterotomy and stenting, and five with endoscopic minor papilla sphincterotomy and endoscopic nasopancreatic drainage), and seven of these ten patients benefited from the endoscopic treatment. In 14 of the 29 patients with incomplete PD--eight with ARP, five with CP, and one with PP--it was suspected that pancreas divisum was the cause of pancreatic disease. Thirteen of the 14 symptomatic patients with incomplete PD underwent successful endoscopic treatments (six with endoscopic minor papilla sphincterotomy and stenting, and seven with endoscopic minor papilla sphincterotomy and endoscopic nasopancreatic drainage), and eight of these 13 patients experienced clinical improvement.

CONCLUSIONS

The prevalence rate, symptom occurrence rate, clinical presentation, and outcomes of endoscopic treatment were similar in patients with complete PD and incomplete PD. Incomplete PD may therefore have similar clinical implications to those of complete PD.

Parathyroid hormone stimulates translocation of protein kinase C isozymes in UMR-106 osteoblastic osteosarcoma cells

Studies with antagonists have provided evidence that protein kinase C (PKC) is involved in several of the actions of parathyroid hormone (PTH) on bone. PTH increases total PKC activity in bone and bone cells. The current studies investigated whether PTH can activate specific PKC isozymes, as demonstrated by translocation of these isozymes from cytosolic to membrane fractions. The isozymes selected for study, alpha, betaI, delta, epsilon, and zeta, were shown previously by us to be present in normal osteoblasts and several osteosarcoma-derived osteoblastic cells. UMR-106 cells, a widely used osteoblastic cell line, were selected for the current study. PKC isozymes in whole cell lysates and cell fractions were visualized by western blotting; isozyme distribution was also visualized by immunofluorescence. The total amounts of the isozymes and their relative distribution between membrane and cytosolic fractions in untreated cells were stable over a range of passages (5-20 from initial plating). In untreated cells, the concentrations of PKC alpha, betaI, and zeta were higher in the cytosol, and PKC delta and epsilon were higher in the membrane fraction. Treatment with 1 or 10 nmol/L PTH for 1 or 5 min stimulated translocation of PKC alpha and betaI, with variable effects on the other isozymes. Treatment with phorbol-12,13-dibutyrate (PDBu), 1 micromol/L for 5 min, elicited similar effects to those of PTH on PKC alpha and betaI. Treatment with PDBu for 48 h resulted in a downregulation of PKC alpha, whereas a 48 h treatment with PTH did not cause downregulation. The results indicate that PTH can affect specific PKC isozymes, providing a mechanism for differential regulation of cellular actions through this pathway.

An Epstein-Barr virus isolated from a lymphoblastoid cell line has a 16-kilobase-pair deletion which includes gp350 and the Epstein-Barr virus nuclear antigen 3A

Epstein-Barr virus (EBV) is associated with human cancers, including nasopharyngeal carcinoma, Burkitt's lymphoma, gastric carcinoma and, somewhat controversially, breast carcinoma. EBV infects and efficiently transforms human primary B lymphocytes in vitro. A number of EBV-encoded genes are critical for EBV-mediated transformation of human B lymphocytes. In this study we show that an EBV-infected lymphoblastoid cell line obtained from the spontaneous outgrowth of B cells from a leukemia patient contains a deletion, which involves a region of approximately 16 kbp. This deletion encodes major EBV genes involved in both infection and transformation of human primary B lymphocytes and includes the glycoprotein gp350, the entire open reading frame of EBNA3A, and the amino-terminal region of EBNA3B. A fusion protein created by this deletion, which lies between the BMRF1 early antigen and the EBNA3B latent antigen, is truncated immediately downstream of the junction 21 amino acids into the region of the EBNA3B sequence, which is out of frame with respect to the EBNA3B protein sequence, and indicates that EBNA3B is not expressed. The fusion is from EBV coordinate 80299 within the BMRF1 sequence to coordinate 90998 in the EBNA3B sequence. Additionally, we have shown that there is no detectable induction in viral replication observed when SNU-265 is treated with phorbol esters, and no transformants were detected when supernatant is used to infect primary B lymphocytes after 8 weeks in culture. Therefore, we have identified an EBV genome with a major deletion in critical genes involved in mediating EBV infection and the transformation of human primary B lymphocytes that is incompetent for replication of this naturally occurring EBV isolate.

Effect of high fat diet on insulin resistance: dietary fat versus visceral fat mass

The purpose of the present study was to determine whether chronic high-fat diet (HF) induces insulin resistance independently of obesity. We randomly divided 40 rats into two groups and fed them either with a HF or with a high-carbohydrate diet (HC) for 8 weeks. Whole body glucose disappearance rate (Rd) was measured using a euglycemic hyperinsulinemic clamp. Firstly, we defined whether insulin resistance by HF was associated with obesity. Plasma glucose and triglyceride concentrations were significantly increased in HF. Rd was decreased (10.6+/-0.2 vs. 9.1+/-0.2 mg/kg/min in HC and HF, respectively) and the hepatic glucose output rate (HGO) was increased in HF (2.2+/-0.3 vs. 4.5+/-0.2 mg/kg/min in HC and HF, respectively). Rd was significantly correlated with %VF (p<0.01). These results implicate that visceral obesity is associated with insulin resistance induced by HF. In addition, to define whether dietary fat induces insulin resistance regardless of visceral obesity, we compared Rd and HGO between groups 1) after matching %VF in both groups and 2) using an ANCOVA to adjust for %VF. After matching %VF, Rd in HF was significantly decreased by 14% (p<0.001) and HGO was significantly increased by 110% (p<0.001). Furthermore, statistical analyses using an ANCOVA also showed Rd for HF was significantly decreased even after adjusting %VF. In conclusion, we suggest that dietary fat per se could induce insulin resistance in rats fed with chronic HF independently of obesity.

Increased levels of circulating autoantibodies to cultured human bronchial epithelial cell in adult patients with nonatopic asthma

The pathogenetic mechanism of nonatopic asthma has not yet been defined. The idea of a possible involvement of autoimmunity in the pathogenesis of nonatopic asthma has been proposed by earlier studies. To evaluate the possible involvement of autoimmune response against bronchial epithelial cell in the pathogenesis of nonatopic asthma, we measured circulating autoantibodies to cultured human bronchial epithelial cell (BEAS-2B cell line) using enzyme-linked immunosorbent assay. We used stored serum samples form 38 age-matched healthy controls, 26 adult patients with atopic asthma, 16 adult patients with nonatopic asthma, and 12 adult patients with systemic lupus erythematosus. Levels of IgG autoantibodies to bronchial epithelial cell were significantly higher in patients with nonatopic asthma (mean+/-SD of absorbance values; 0.135+/-0.030) and systemic lupus erythematosus (0.293+/-0.181) than in healthy controls (0.112+/-0.016) and patients with atopic asthma (0.116+/-0.031) (p<0.05). This study showed that levels of circulating IgG autoantibodies to bronchial epithelial cell were increased in adult patients with nonatopic asthma. Further studies are needed to evaluate the possible involvement of autoimmune mechanism in the pathogenesis of nonatopic asthma.

Transport risk index of physiologic stability: a practical system for assessing infant transport care

OBJECTIVES

To develop and validate a practical, physiology-based system for assessment of infant transport care.

STUDY DESIGN

Transport teams prospectively collected data, before and after transport, from 1723 infants at 8 neonatal intensive care units (NICUs) from 1996 to 1997. We used logistic regression to derive a prediction model for mortality within 7 days of NICU admission and develop the Transport Risk Index of Physiologic Stability (TRIPS). We validated TRIPS for prediction of 7-day mortality, total NICU mortality (until discharge), and severe (> or =grade 3) intraventricular hemorrhage.

RESULTS

TRIPS comprises 4 empirically weighted items (temperature, blood pressure, respiratory status, and response to noxious stimuli). TRIPS discriminated 7-day NICU mortality and total NICU mortality from survival with receiver operating characteristic areas of 0.83 and 0.76, respectively. There was good calibration across the full range of TRIPS scores and gestational age groups. Increase and decrease in TRIPS scores after transport were associated with increased and decreased mortality, respectively. The receiver operating characteristic area for TRIPS prediction of severe intraventricular hemorrhage was 0.74. Addition of TRIPS improved performance of prediction models in which gestational age and baseline population risk variables were used.

CONCLUSIONS

TRIPS is validated for infant transport assessment.

Improved outcome of preterm infants when delivered in tertiary care centers

OBJECTIVE

Previous studies that compared outcomes of infants born outside tertiary care centers (outborn) with those born in tertiary care centers (inborn) did not account for admission illness severity and perinatal risks. The objective of this study was to examine whether outborn status is associated with higher mortality and morbidity, after adjustment for perinatal risks and admission illness severity (using the Score for Neonatal Acute Physiology, Version II [SNAP-II]) among preterm infants who were admitted to Neonatal Intensive Care Units (NICUs).

METHODS

Logistic regression analysis was used to compare the risk-adjusted outcomes of 3769 singleton infants born at or before 32 weeks' gestation, who were admitted to 17 Canadian NICUs during 1996-1997.

RESULTS

Outborn and inborn infants had significantly different gestational ages, perinatal risk factors (maternal hypertension, prenatal care, antenatal corticosteroid therapy, 5-minute Apgar score, delivery type, small for gestational age) and admission SNAP-II. Outborn infants were at higher risk of death (adjusted odds ratio [OR] 1.7, 95% confidence interval [CI] 1.2, 2.5), grade III or IV intraventricular hemorrhage (adjusted OR 2.2, 95% CI 1.5, 3.2), patent ductus arteriosus (adjusted OR 1.6, 95% CI 1.2, 2.1), respiratory distress syndrome (adjusted OR 4.8, 95% CI 3.6, 6.3), and nosocomial infection (adjusted OR 2.5, 95% CI 1.9, 3.3), even after adjusting for perinatal risks and admission illness severity.

CONCLUSIONS

Outborn infants were less mature and more ill than inborn infants at NICU admission. However, even after adjustment for perinatal risks and admission illness severity, inborn infants had better outcomes than outborn infants. Our results support in-utero transfer of high-risk pregnancies to a tertiary level facility.

In vitro analysis of an RNA binding site within the N-terminal 30 amino acids of the southern cowpea mosaic virus coat protein

Southern cowpea mosaic virus (SCPMV) is a positive-sense RNA virus with T = 3 icosahedral symmetry. The coat protein (CP) has two domains, the random (R) domain and the shell (S) domain. The R domain is formed by the N-terminal 64 amino acids (aa) and is localized to the interior of the particle where it is expected to interact with the viral RNA. The R domain (aa 1--57) was expressed in Escherichia coli as a recombinant protein (rWTR) containing a nonviral C-terminal extension with two histidine tags. The RNA binding site of the R domain was identified by Northwestern blotting and electrophoretic mobility shift assay (EMSA) using recombinant wild-type and mutant R domain proteins. Deletions within the R domain revealed that the RNA binding site is localized to its N-terminal 30 aa. RNA binding by this element was found to be nonspecific with regard to RNA sequence and was sensitive to high salt concentrations, suggesting that electrostatic interactions are important for RNA binding by the R domain. The RNA binding site includes 11 basic residues, eight of which are located in the arginine-rich region between aa 22 and 30. It was demonstrated using alanine substitution mutants that the basic residues of the arginine-rich region but not those present at positions 3, 4, and 7 are necessary for RNA binding. None of the basic residues within the arginine-rich region are specifically required for RNA binding, but the overall charge of the N-terminal 30 aa is important. Proline substitution mutations within the N-terminal 30 aa, and alanine substitutions for prolines at positions 18, 20, and 21, did not affect the RNA binding activity of the R domain. However, it was demonstrated by circular dichroism (CD) that the conformation of the N-terminal 30 aa of the R domain changes from a random coil to an alpha-helix in the presence of 50% trifluoroethanol (TFE). The possible role for this structural change in RNA binding by the R domain is discussed.

Decay of the peroxide intermediate in laccase: reductive cleavage of the O-O bond

Laccase is a multicopper oxidase that contains four Cu ions, one type 1, one type 2, and a coupled binuclear type 3 Cu pair. The type 2 and type 3 centers form a trinuclear Cu cluster that is the active site for O(2) reduction to H(2)O. To examine the reaction between the type 2/type 3 trinuclear cluster and dioxygen, the type 1 Cu was removed and replaced with Hg(2+), producing the T1Hg derivative. When reduced T1Hg laccase is reacted with dioxygen, a peroxide intermediate (P) is formed. The present study examines the kinetics and mechanism of formation and decay of P in T1HgLc. The formation of P was found to be independent of pH and did not involve a kinetic solvent isotope effect, indicating that no proton is involved in the rate-determining step of formation of P. Alternatively, pH and isotope studies on the decay of P revealed that a proton enhances the rate of decay by 10-fold at low pH. This process shows an inverse k(H)/k(D) kinetic solvent isotope effect and involves protonation of a nearby residue that assists in catalysis, rather than direct protonation of the peroxide. Decay of P also involves a significant oxygen isotope effect (k(16)O(2)/k(18)O(2)) of 1.11 +/- 0.05, indicating that reductive cleavage of the O-O bond is the rate-determining step in the decay of P. The activation energy for this process was found to be approximately 9.0 kcal/mol. The exceptionally slow rate of decay of P is explained by the fact that this process involves a 1e(-) reductive cleavage of the O-O bond and there is a large Franck-Condon barrier associated with this process. Alternatively, the 2e(-) reductive cleavage of the O-O bond has a much larger driving force which minimizes this barrier and accelerates the rate of this reaction by approximately 10(7) in the native enzyme. This large difference in rate for the 2e(-) versus 1e(-) process supports a molecular mechanism for multicopper oxidases in which O(2) is reduced to H(2)O in two 2e(-) steps.

Risk factors for recurrence of primary bile duct stones after endoscopic biliary sphincterotomy

BACKGROUND

Endoscopic biliary sphincterotomy (EST) is a well-established procedure for bile duct stone extraction. Bile duct stones can be classified as primary or secondary. However, few data are available on the recurrence of primary and secondary bile duct stones after EST. Therefore risk factors for the recurrence of primary bile duct stones after EST were prospectively studied.

METHODS

Between 1991 and 1997, 61 patients underwent EST for primary bile duct stones. All met the following criteria: (1) previous cholecystectomy without bile duct exploration, (2) detection of bile duct stones at least 2 years after initial cholecystectomy. Mean follow-up was 2.2 years. Fourteen patients were lost to follow-up. The recurrence of primary bile duct stones was defined as the detection of bile duct stones no sooner than 6 months after complete clearance of primary bile duct stones.

RESULTS

The overall recurrence rate of primary bile duct stones was 21% (10 of 47). Two significant risk factors for recurrence were identified by multivariate analysis: (1) patients with a bile duct diameter of 13 mm or greater after stone removal had recurrences more frequently than those with a duct diameter of 13 mm or less, and (2) patients whose papilla was located on the inner rim or deep within a diverticulum, so that the papillary orifice was not visible endoscopically, had more frequent recurrences than patients with a papilla outside the diverticulum, or no peripapillary diverticulum.

CONCLUSION

The independent risk factors for recurrence of primary bile duct stones were sustained dilation of the bile duct even after complete removal of stones and location of the papilla on the inner rim or deep within a diverticulum.

Quantification of F-18 FDG PET images in temporal lobe epilepsy patients using probabilistic brain atlas

A probabilistic atlas of the human brain (Statistical Probabilistic Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). It is a good frame for calculating volume of interest (VOI) in many fields of brain images. After calculating the counts in VOI using the product of probability of SPAM images and counts in FDG images, asymmetric indices (AI) were calculated and used for finding epileptogenic zones in mesial temporal lobe epilepsy (mTLE). FDG PET images from 18 surgically confirmed mTLE patients and 22 age-matched controls were spatially normalized to the average brain MRI template of ICBM. Counts from normalized PET images were multiplied with the probability of 12 VOIs from SPAM images in both temporal lobes. Finally AI were calculated on each pair of VOIs, and compared with visual assessment. If AI of mTLE patients were not within 2.9 standard deviation from those of normal control group (P < 0.008; Bonferroni correction for P < 0.05), epileptogenic zones were considered to be found successfully. The counts of VOIs in the normal control group were symmetric (AI < 4.3%, paired t test P > 0.05) except for those of the inferior temporal gyrus (P < 0.001). By AIs in six pairs of VOIs, PET in mTLE had deficit on one side (P < 0.05). Lateralization was correct in only 14/18 of patients by AI, but 17/18 were consistent with visual inspection. In three patients with normal AI, PET images were symmetric on visual inspection. The asymmetric indices obtained by taking the product of the statistical probability anatomical map and FDG PET, correlated well with visual assessment in mTLE patients. SPAM is useful for the quantification of VOIs in functional images.

In vivo magnetic resonance (MR) study of fatty liver: importance of intracellular ultrastructural alteration for MR tissue parameters change

Fatty liver is thought to have a shorter T1 relaxation time than normal liver tissue, due to the accumulation of triglyceride. Previous studies regarding T1 and T2 relaxation times, however, show widely different results. In order to elucidate the mechanism responsible for the changes and diversity of relaxation times in fatty liver, we created two animal models in 14 rabbits, one acute form (N = 6) and the other chronic form (N = 8). Four rabbits were taken as a control group. Tissue relaxation times and the magnetization transfer (MT) effect of the liver tissue in these two models were measured. The results were correlated with biochemical analysis of water and fat content and histological examination, including findings in light microscopy and electron microscopy. Although the fatty ratio in both forms of fatty liver was similar, their tissue relaxation rate and MT effect were significantly different. The acute form showed prolongation of both T1 and T2 relaxation times (512 +/- 51 msec vs. 710 +/- 95 msec and 39 +/- 1.8 msec vs. 48 +/- 3.7 msec, respectively) and a decrease of the MT effect (50 +/- 5.1% vs. 38 +/- 6.3%), compared to those of the control group and preinduction liver. The chronic form showed shorter T1 and T2 values (526 +/- 36 msec vs. 406 +/- 56 msec and 36 +/- 1.6 msec vs. 33 +/- 2.3 msec, respectively) and a stronger MT effect (21 +/- 0.9% vs. 26 +/- 2.3%). In acute form fatty liver, electron microscopic examination revealed dramatic subcellular changes, such as vesicular transformation, a markedly increased amount of smooth endoplasmic reticulum (SER), and disruption of the crista. These changes were not found in the chronic form fatty liver. From this study, we concluded that the ultrastructural alteration in the subcellular organelles of hepatocyte might play a crucial role for the chameleonic presentation of MR tissue parameters in fatty liver.

Oligoclonal B lymphocyte expansion in the synovium of a patient with Behçet's disease

OBJECTIVE

Plasma cell infiltration is observed in recurrent arthritis associated with Behçet's disease (BD). The immune mechanism underlying B lymphocyte proliferation in the synovium is unclear. One hypothesis involves nonspecific polyclonal activation and another involves antigen-driven activation. The present study was undertaken to test both hypotheses and identify immunoglobulin genes that are clonally expanded in the synovium.

METHODS

Peripheral blood lymphocytes (PBL) and synovial cells from a patient with BD and PBL from a healthy control subject were obtained. Complementarity-determining region 3 (CDR3) fingerprinting analysis and nucleotide sequence analysis of Ig transcripts derived from clonally expanded B lymphocytes were performed in parallel.

RESULTS

Of 44 mu heavy chain clones of the VH4 family identified in the synovial tissue from the BD patient, 8 clones showed identical nucleotide sequences, and therefore, 18.2% were clonally expanded. For y heavy chain, 4 of 50 clones of the VH3 family showed nearly identical sequences; therefore, 4-8% were clonally expanded. The kappa light chain did not show a dominant band, but a clone with a 12-amino acid CDR3 showed 3% clonal expansion. Somatic mutations were frequently observed, with a high ratio of replacement to silent mutations in the CDRs compared with the framework regions. Three Ig genes expressed in the clonally expanded B lymphocytes were derived from germline gene segments reported to be involved in the production of autoantibodies.

CONCLUSION

These results support the hypothesis that antigen-driven clonal B lymphocyte proliferation occurs in the synovium in BD. Immunoglobulin transcripts clonally expanded in the synovium were identified.

Mutations of tumor necrosis factor-related apoptosis-inducing ligand receptor 1 (TRAIL-R1) and receptor 2 (TRAIL-R2) genes in metastatic breast cancers

Several lines of evidence suggest that apoptosis dysregulation plays an important role in cancer metastasis. In this study, to explore the possibility that the mutations of death receptors are involved in the metastasis mechanism, we analyzed the death domains of Fas and tumor necrosis factor-related apoptosis-inducing ligand-receptor 1 and -2 (TRAIL-R1 and -R2) genes for the detection of somatic mutations in 57 breast cancers with (n = 34) or without (n = 23) metastasis to the regional lymph nodes. We found seven mutations (three TRAIL-R1 and four TRAIL-R2 mutations), and these mutations were detected only in the breast cancers with metastasis. Furthermore, we also analyzed the allelic losses of chromosome 8p21-22, where TRAIL-R1 and R2 reside in the same series of breast cancers, and found that the allelic losses were significantly higher in metastatic breast cancers. We expressed the tumor-derived TRAIL-R1 and TRAIL-R2 mutants in 293 cells and found that apoptosis was suppressed. These data suggest that TRAIL-R1 and R2 genes are relevant to the frequent loss of chromosome 8p21-22 in breast cancer and that the inactivating mutations of TRAIL-R1 and -R2 genes play a role in the metastasis of breast cancer.

Neuroimaging findings of cortical dyslamination with cytomegaly

PURPOSE

Our aims were to identify (a) the characteristic magnetic resonance imaging (MRI) findings of cortical dyslamination with cytomegaly, including dysplastic and destructive lesions; (b) the relationship between MRI findings and pathologic characteristics; (c) the diagnostic role of functional neuroimaging studies in patients with these pathologies.

METHODS

The series consisted of 23 adult patients who had proven cortical dyslamination with cytomegaly. The abnormalities found on MRI were subdivided according to the patterns of involvement. They also were compared with the patients' pathologic characteristics. With visual qualitative analysis, [18F]fluorodeoxyglucose with positron emission tomography (FDG-PET), and ictal single-photon emission computed tomography (SPECT), observations were classified as localizing, lateralizing, nonlateralizing, false-localizing, and false-lateralizing. The standard for correct localization of neuroimages was defined to be the resected lobe.

RESULTS

Focal abnormalities were found in 14 cases by MRI. Six cases showed typical MRI findings of focal cortical dysplasia, with focal areas of cortical thickening with or without poor grey-white matter differentiation. Focal subcortical high signal intensities on T2-weighted images occurred in two cases. Six patients had the focal destructive pattern. Three of eight cases with normal MRI and four of eight cases with the nondestructive cortical dysplasia pattern had balloon cells. However, these were not found in six patients with the destructive MRI pattern. FDG-PET localized the pathologic lobe in 13 (65%) of 20 cases, and ictal SPECT achieved this in 11 (61.1%) of 18 cases. FDG-PET and ictal SPECT also correctly localized the pathologic lobe in four and two cases with normal MRI, respectively.

CONCLUSIONS

Two distinct patterns of abnormal MRI were found in the pathology of cortical dyslamination with cytomegaly. These dysplastic and destructive patterns might reflect different pathogeneses, such as the time of insult. FDG-PET and ictal SPECT have confirmatory and independent diagnostic roles in localizing epileptogenic foci.

High glucose induces MCP-1 expression partly via tyrosine kinase-AP-1 pathway in peritoneal mesothelial cells

BACKGROUND

High glucose in peritoneal dialysis solutions has been implicated in the pathogenesis of peritoneal fibrosis in chronic ambulatory peritoneal dialysis (CAPD) patients. However, the mechanisms are not very clear. Peritoneal macrophages seem to participate in the process of peritoneal fibrosis and monocyte chemoattractant protein-1 (MCP-1) plays a key role in the recruitment of monocytes toward the peritoneal cavity. However, little is known about the effect of high glucose on MCP-1 expression and its signal transduction pathway in human peritoneal mesothelial cells.

METHODS

Mesothelial cells were cultured with glucose (5 to 100 mmol/L) or mannitol chronically for up to seven days. MCP-1 expression of mRNA and protein was measured by Northern blot analysis and enzyme-linked immunosorbent assay (ELISA). Chemotactic activity of high-glucose-conditioned culture supernatant was measured by chemotactic assay. To examine the roles of the transcription factors activator protein-1 (AP-1) and nuclear factor-kappaB (NF-kappaB), electrophoretic mobility shift assay (EMSA) was performed.

RESULTS

Glucose induced MCP-1 mRNA expression in a time- and dose-dependent manner. MCP-1 protein in cell culture supernant was also increased. Equivalent concentrations of mannitol had no significant effect. High-glucose-conditioned supernatant possessed an increased chemotactic activity for monocytes, which was neutralized by anti-MCP-1 antibody. EMSA revealed that glucose increased the AP-1 binding activity in a time- and dose-dependent manner, but not NF-kappaB. Curcumin, an inhibitor of AP-1, dose-dependently suppressed the induction of MCP-1 mRNA by high glucose. Tyrosine kinase inhibitors such as genistein (12.5 to 50 micromol/L) and herbimycin A (0.1 to 1 micromol/L) inhibited the high-glucose-induced MCP-1 mRNA expression in a dose-dependent manner, and also suppressed the high-glucose-induced AP-1 binding activity.

CONCLUSIONS

: High glucose induced mesothelial MCP-1 expression partly via the tyrosine kinase-AP-1 pathway.