Characteristics and surgical outcomes of cleft palate in kabuki syndrome: a case series of 11 patients

Objective

A significant number of patients with KS have cleft palate (CP) or submucous cleft palate (SMCP) and show delayed speech development. However, few reports have discussed the characteristics of CP in KS and the outcomes of postoperative speech development. The purpose of this study was to investigate the characteristics and surgical outcomes of CP in patients with KS, and to discuss the importance of the diagnosis of CP or SMCP.

Methods

We conducted a retrospective study on patients with clinically diagnosed KS who underwent palatoplasty. Clinical and surgical data were collected from patients’ medical records, and velopharyngeal function was evaluated using nasopharyngoscopy and speech analysis.

Results

In 11 cases, 5 patients had CP (45.5%) and 6 had SMCP (54.5%). Four patients who were genetically tested had a pathogenic variant of KMT2D. Seven of nine patients (77.8%) who underwent conventional palatoplasty showed velopharyngeal insufficiency and hypernasality. All patients who underwent pharyngeal flap surgery achieved velopharyngeal competency. Statistical analysis revealed a statistically significant difference in postoperative results between non-syndromic and KS patients.

Conclusion

Patients with SMCP may be more common than previously reported. The results showed that it is difficult to produce optimal results with conventional palatoplasty; therefore, pharyngeal flap surgery should be considered as a treatment to obtain favorable results. Pharyngeal flap surgery in patients with KS should be carefully designed based on speech evaluation and nasopharyngoscopic findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02852-4.

First Direct Measurement of ^{22}Mg(α,p)^{25}Al and Implications for X-Ray Burst Model-Observation Comparisons

Type-I x-ray bursts can reveal the properties of an accreting neutron star system when compared with astrophysics model calculations. However, model results are sensitive to a handful of uncertain nuclear reaction rates, such as ^{22}Mg(α,p). We report the first direct measurement of ^{22}Mg(α,p), performed with the Active Target Time Projection Chamber. The corresponding astrophysical reaction rate is orders of magnitude larger than determined from a previous indirect measurement in a broad temperature range. Our new measurement suggests a less-compact neutron star in the source GS1826-24.

Erratum: Direct Observation of Proton Emission in ^{11}Be [Phys. Rev. Lett. 123, 082501 (2019)]

This corrects the article DOI: 10.1103/PhysRevLett.123.082501.

P1740Clinical impact of symptom onset-to-balloon time and door-to-balloon time on 1-year adverse event in patients with ST-segment elevation myocardial infarction

Background and objectives

The impact of treatment delays to reperfusion on patient mortality after primary percutaneous coronary intervention (PCI) for ST elevation myocardial infarction (STEMI) is controversial. we evaluated the relation between the delay in the time to reperfusion during primary PCI and the 1-year clinical outcome of patients with STEMI treated by primary angioplasty.

Methods

The study enrolled 6,676 patients (age, 62.5±12.6 years; 26.5% female) with STEMI who underwent primary angioplasty onset between November 2005 and March 2012 from the KAMIR and KorMI Registry. The patients were divided into three groups according to the symptom onset-to-balloon (STB) time: group I, II, III (≤180 minutes, >180 ∼ ≤360 minutes, >360 minutes), and divided into three groups according to the door-to-balloon (DTB) time: group A, B, C (≤90 minutes, >90 ∼ ≤120 minutes, >120 minutes). The 1-year cardiac death and major adverse cardiac event (MACE) rates were compared among the three groups of time variables

Results

The cardiac death rate was 7.9% and MACE rate was 16.9% at one year follow-up. The 1-year cardiac death rate among STB time groups were significantly higher in group II (95% CI=1.05–2.60:p=0.030) and group III (95% CI=1.14–2.74:p=0.011), while that among DTB time groups were not significantly different based on a multivariate Cox proportional analysis, which was adjusted by age, sex, diabetes mellitus, hypertension, systolic blood pressure, left ventricular ejection fraction, peak level of CK-MB, anterior myocardial infarction. The 1-year MACE rate were not significantly different among STB time groups and DTB time group A, B, but was significantly higher in group C (95% CI=1.08–1.58:p=0.006).

Conclusions

These results suggest that, in patient with STEMI treated by primary angioplasty, STB time rather than DTB time was related 1-year clinical outcome especially cardiac death after adjustment for baseline characteristics. Therefore, all efforts should be made to shorten the total ischemic time in patients with acute myocardial infarction

Direct Observation of Proton Emission in ^{11}Be

The elusive β^{-}p^{+} decay was observed in ^{11}Be by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber in an experiment performed at ISAC-TRIUMF. The measured β^{-}p^{+} branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in ^{11}B above the proton separation energy.

First Measurement of the g Factor in the Chiral Band: The Case of the ^{128}Cs Isomeric State

The g factor of the 56 ns half-life isomeric state in ^{128}Cs has been measured using the time-differential perturbed angular distribution method. This state is the bandhead of the positive-parity chiral rotational band, which emerges when an unpaired proton, an unpaired neutron hole, and an even-even core are coupled such that their angular momentum vectors are aplanar (chiral configuration). g-factor measurements can give important information on the relative orientation of the three angular momentum vectors. The measured g factor g=+0.59(1) shows that there is an important contribution of the core rotation in the total angular momentum of the isomeric state. Moreover, a quantitative theoretical analysis supports the conclusion that the three angular momentum vectors lie almost in one plane, which suggests that the chiral configuration in ^{128}Cs demonstrated in previous works by characteristic patterns of electromagnetic transitions appears only above some value of the total nuclear spin.

Clinical Significance of the Levator Veli Palatini Muscle in Velocardiofacial Syndrome Patients

Background:

Anatomical variation and deficits of velocardiofacial syndrome patients are related to unsatisfactory treatment results in surgical correction of speech abnormalities. The main purpose of the article is to investigate the clinical significance of thinned levator veli palatini muscle in VCFS patients.

Methods:

The authors reviewed medical records of all children with velocardiofacial syndrome who received pharyngeal flap surgery between March 2007 and September 2015. Data including thickness of levator veli palatini in magnetic resonance examination; preoperative velopharyngeal gap size from nasoendoscopy; and preoperative and postoperative speech outcomes were collected.

Results:

Total of 36 velocardiofacial syndrome patients with preoperative objective data and postoperative speech outcomes were identified. Preoperative velopharyngeal gap showed significant correlation with thickness of levator veli palatini (correlation coefficient: 0.297/0.397, P = .02/.03) and gap size showed correlation with postoperative speech improvement (0.347/0.413, P = .04/.02). However, muscle thickness showed no correlation with speech outcomes (0.046/0.037, P = .77/.86).

Conclusion:

Thinned levator veli palatini muscle in velocardiofacial syndrome patients are related to widened velopharyngeal gap and production of hypernasal speech, and can give negative impact on postoperative surgical outcome of pharyngeal flap surgery.

Abstract P2-08-19: Prognostication of HER family gene expression collaborate with ESR1 expression in patients with triple negative breast cancer

Background: Triple-negative breast cancer (TNBC) consists of heterogeneous sub-population. Although many investigators made an effort to categorize and classify TNBCs using genetic expressions, it is still needed to be defined for prognostication Traditionally, HER family genes have been known to contribute mammalian glands formation and breast cancer generation as well as ESR gene. Moreover, target agents for HER family genes have been already developed. Accordingly, we investigated the expression profiles of HER family genes with ESR in patients with TNBC to categorize into sub-types and determine the prognostic value of HER family genes in search of clinical implications.

Methods : We investigated the results of the nCounter expression assay (NanoString®) for ERBB1, ERBB2, ERBB3, ERBB4 and ESR1 using mRNA extract from paraffin-embedded tumor tissues in 203 patients diagnosed as TNBC. We used the results of nCounter expression assay using 84 TNBC tissues for validation and 52 breast cancer tissues diagnosed as other subtypes to control the expression assay results of these five genes.

Results: Two-hundred and three patients were diagnosed as TNBC from 2000 to 2004 and received adjuvant chemotherapy after curative surgery. Eighty-four TNBC patients for validation set and 52 patients diagnosed as other subtypes for control set were selected from the patients diagnosed as breast cancer from 2005 to 2010 and received curative surgery. Through analyzing 5 genes using the nCounter expression profiles from 203 TNBC tissues, we found that increased expression of ERBB4 was associated with poor prognosis by survival analysis (5 year disease recurrence free survival (DRFS), low vs. high expression [cut-off: median]: 90.1% vs. 80.2%; p =.002). This trend was still remained in validation set composed of TNBC (5 year DRFS, low vs. high expression [cut-off : median]: 61.1% vs. 44.0%), whereas was not observed in other subtypes of breast cancer (44.4% vs. 80.8%). The Kaplan-Meier estimates of the rates of 5 year DRFS in the subgroups classified according to the level of 5 genes expression showed that the group of higher expression of all HER family genes and lower expression of ESR1 gene had dismal prognosis rather than other groups in patients with TNBC (5 year DRFS, this group vs. others: 50.0% vs. 88.2%; p <.001). In a multivariate Cox regression model, ERBB4 expression identified as a useful marker for predicting long-term prognosis in patients with TNBC although other HER family genes and ESR1 expressions did not predict prognosis of TNBC with statistical significance (Table 1).

Impact of the m RNA expression levels of ERBB family and ESR1 on DRFS Hazard Ratio95% CIP-valueStage  <.001I1.0NA IIA1.200.40-3.57 IIB3.751.20-11.74 IIIA5.461.55-9.24 IIIC59.9214.30-251.12 EGFR  .167Low1.0NA High1.690.80-3.55 ERBB2  .057Low1.0NA High0.430.18-1.03 ERBB3  .061Low1.0NA High2.200.96-5.04 ERBB4  .016Low1.0NA High2.681.20-5.95 ESR1  .113Low1.0NA High0.570.28-1.15 

Conclusions: The expression profile of HER family genes could be used as a prognostic marker in patients with TNBC. Further study is needed to identify the expression profiles of HER family gene as predictive marker of HER targeting treatment in patients with TNBC.

Citation Format: Kim J-Y, Ahn T, Jung HH, Park K, Do I-G, Kil WH, Kim SW, Lee JE, Nam SJ, Ahn JS, Park YH, Im Y-H. Prognostication of HER family gene expression collaborate with ESR1 expression in patients with triple negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-19.

Prenatal testosterone excess decreases neurokinin 3 receptor immunoreactivity within the arcuate nucleus KNDy cell population

Prenatal exposure of the female ovine foetus to excess testosterone leads to neuroendocrine disruptions in adulthood, as demonstrated by defects in responsiveness with respect to the ability of gonadal steroids to regulate gonadotrophin-releasing hormone (GnRH) secretion. In the ewe, neurones of the arcuate nucleus (ARC), which co-expresses kisspeptin, neurokinin B (NKB) and dynorphin (termed KNDy cells), play a key role in steroid feedback control of GnRH and show altered peptide expression after prenatal testosterone treatment. KNDy cells also co-localise NKB receptors (NK3R), and it has been proposed that NKB may act as an autoregulatory transmitter in KNDy cells where it participates in the mechanisms underlying steroid negative-feedback. In addition, recent evidence suggests that NKB/NK3R signalling may be involved in the positive-feedback actions of oestradiol leading to the GnRH/luteinising hormone (LH) surge in the ewe. Thus, we hypothesise that decreased expression of NK3R in KNDy cells may be present in the brains of prenatal testosterone-treated animals, potentially contributing to reproductive defects. Using single- and dual-label immunohistochemistry we found NK3R-positive cells in diverse areas of the hypothalamus; however, after prenatal testosterone treatment, decreased numbers of NK3R immunoreactive (-IR) cells were seen only in the ARC. Moreover, dual-label confocal analyses revealed a significant decrease in the percentage of KNDy cells (using kisspeptin as a marker) that co-localised NK3R. To investigate how NKB ultimately affects GnRH secretion in the ewe, we examined GnRH neurones in the preoptic area (POA) and mediobasal hypothalamus (MBH) for the presence of NK3R. Although, consistent with earlier findings, we found no instances of NK3R co-localisation in GnRH neurones in either the POA or MBH; in addition, > 70% GnRH neurones in both areas were contacted by NK3R-IR presynaptic terminals suggesting that, in addition to its role at KNDy cell bodies, NKB may regulate GnRH neurones by presynaptic actions. In summary, the finding of decreased NK3R within KNDy cells in prenatal testosterone-treated sheep complements previous observations of decreased NKB and dynorphin in the same population, and may contribute to deficits in the feedback control of GnRH/LH secretion in this animal model.

Synthetic lethal screening reveals FGFR as one of the combinatorial targets to overcome resistance to Met-targeted therapy

Met is a receptor tyrosine kinase that promotes cancer progression. In addition, Met has been implicated in resistance of tumors to various targeted therapies such as epidermal growth factor receptor inhibitors in lung cancers, and has been prioritized as a key molecular target for cancer therapy. However, the underlying mechanism of resistance to Met-targeting drugs is poorly understood. Here, we describe screening of 1310 genes to search for key regulators related to drug resistance to an anti-Met therapeutic antibody (SAIT301) by using a small interfering RNA-based synthetic lethal screening method. We found that knockdown of 69 genes in Met-amplified MKN45 cells sensitized the antitumor activity of SAIT301. Pathway analysis of these 69 genes implicated fibroblast growth factor receptor (FGFR) as a key regulator for antiproliferative effects of Met-targeting drugs. Inhibition of FGFR3 increased target cell apoptosis through the suppression of Bcl-xL expression, followed by reduced cancer cell growth in the presence of Met-targeting drugs. Treatment of cells with the FGFR inhibitors substantially restored the efficacy of SAIT301 in SAIT301-resistant cells and enhanced the efficacy in SAIT301-sensitive cells. In addition to FGFR3, integrin β3 is another potential target for combination treatment with SAIT301. Suppression of integrin β3 decreased AKT phosphorylation in SAIT301-resistant cells and restored SAIT301 responsiveness in HCC1954 cells, which are resistant to SAIT301. Gene expression analysis using CCLE database shows that cancer cells with high levels of FGFR and integrin β3 are resistant to crizotinib treatment, suggesting that FGFR and integrin β3 could be used as predictive markers for Met-targeted therapy and provide a potential therapeutic option to overcome acquired and innate resistance for the Met-targeting drugs.

Assessing sources of inconsistencies in genotypes and their effects on genome-wide association studies with HapMap samples

The discordance in results of independent genome-wide association studies (GWAS) indicates the potential for Type I and Type II errors. We assessed the repeatibility of current Affymetrix technologies that support GWAS. Reasonable reproducibility was observed for both raw intensity and the genotypes/copy number variants. We also assessed consistencies between different SNP arrays and between genotype calling algorithms. We observed that the inconsistency in genotypes was generally small at the specimen level. To further examine whether the differences from genotyping and genotype calling are possible sources of variation in GWAS results, an association analysis was applied to compare the associated SNPs. We observed that the inconsistency in genotypes not only propagated to the association analysis, but was amplified in the associated SNPs. Our studies show that inconsistencies between SNP arrays and between genotype calling algorithms are potential sources for the lack of reproducibility in GWAS results.

Detection of heavy metal and hydrocarbon contamination using a miniature resistivity probe

The usefulness of the electrical resistivity method for characterization of contaminated sites has been studied in many ways. The most commonly used device is a cone penetrometer that utilizes two or four electrodes to measure electrical resistivity (or conductivity) during a cone penetration test (CPT) along a vertical or horizontal alignment. This paper introduces a new miniature resistivity probe (MRP) that can potentially be deployed from a sampling platform to detect contaminant plumes prior to collecting soil samples. Following bench-scale tests aimed at quantifying the sensitivity of the MRP to various operating and environmental parameters, the response of the MRP in sandy soil containing various concentrations of tour heavy metals (Cu, Zn, Pb and Ni) and two hydrocarbons (phenol and gasoline) is evaluated. The test data revealed that the MRP has the potential to serve as an indexing tool for rapidly delineating contaminant plumes where heavy metals are present. The results for hydrocarbons were less conclusive, ranging from moderate ability to differentiate contaminated and non-contaminated soils for phenol to poor differentiation ability for gasoline.

Stabilization of nuclear isovector valence-shell excitations

Excited states in 138Ce have been studied via the 12C(138Ce, 138Ce*) Coulomb excitation reaction at 480 MeV. Relative cross sections have been determined from the gamma-ray yields observed with Gammasphere. The E2 and M1 strength distributions between the lowest six 2+ states up to 2.7 MeV enables us to identify the 2(4)+ state in 138Ce as the dominant fragment of the one-phonon 2(1,ms)+ mixed-symmetry state. Mixing between this level and a nearby isoscalar state is observed and is more than 4 times larger than in the neighboring isotone 136Ba. This is direct evidence that the stability of mixed-symmetry states strongly depends on the underlying subshell structure.

New optical frequency domain differential mode delay measurement method for a multimode optical fiber

A novel mode analysis method and differential mode delay (DMD) measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

Effects of lipids on the interaction of SecA with model membranes

The effects of nonlamellar-prone lipids, diacylglycerol and phosphatidylethanolamine (PE), on the kinetic association of SecA with model membranes were examined by measuring changes in the intrinsic emission fluorescence with a stopped-flow apparatus. Upon interaction with standard liposomes composed of 50 mol% dioleolyphosphatidylcholine (DOPC) and 50 mol% of dioleoylphosphatidylglycerol (DOPG), the intrinsic fluorescence intensity of SecA was decreased after a lapse of time with a rate constant of 0.0049 s(-1). When the DOPC of the standard vesicles was gradually replaced with either dioeloyl PE (DOPE) or Escherichia coli (E. coli) PE, the rate constant increased appreciably as a function of PE concentration, in the order DOPE > E. coli PE. In addition, when the PE of E. coli PE/DOPG (50/50) vesicles was replaced with more than 5 mol% dioleoylglycerol (DOG), the rate constant further increased by 40%. The incorporation of nonlamellar-prone lipids in the vesicles also enhanced the binding of SecA to model membranes in the order DOPE > or = E. coli PE/DOG > E. coli PE > DOPC. These results provide the first kinetic evidence for the importance of nonlamellar-prone phospholipids for the association rate of SecA with membranes.

ORE9, an F-box protein that regulates leaf senescence in Arabidopsis

Senescence is a sequence of biochemical and physiological events that constitute the final stage of development. The identification of genes that alter senescence has practical value and is helpful in revealing pathways that influence senescence. However, the genetic mechanisms of senescence are largely unknown. The leaf of the oresara9 (ore9) mutant of Arabidopsis exhibits increased longevity during age-dependent natural senescence by delaying the onset of various senescence symptoms. It also displays delayed senescence symptoms during hormone-modulated senescence. Map-based cloning of ORE9 identified a 693-amino acid polypeptide containing an F-box motif and 18 leucine-rich repeats. The F-box motif of ORE9 interacts with ASK1 (Arabidopsis Skp1-like 1), a component of the plant SCF complex. These results suggest that ORE9 functions to limit leaf longevity by removing, through ubiquitin-dependent proteolysis, target proteins that are required to delay the leaf senescence program in Arabidopsis.

Microscopic polyangiitis complicated with massive intestinal bleeding

Microscopic polyangiitis (MPA) is associated with renal dysfunction, in most cases, and occasionally with pulmonary hemorrhage. However, massive intestinal bleeding is a rare manifestation. We report a case of MPA in a man who developed arterial bleeding in the small intestine. A 74-year-old man was admitted after enduring a fever for 4 weeks. Laboratory examination revealed leucocytosis with neutrophil predominance, and renal dysfunction was noted. He did not respond to treatment with antibiotics, and the worsened renal function soon required hemodialysis. On the seventh hospital day, he suddenly developed massive melena. A colonoscopic examination suggested bleeding in the small intestine, and abdominal angiography demonstrated that the bleeding originated in a branch of the ileal artery. Hemostasis was achieved by transarterial embolization (TAE), but the patient suffered a massive pulmonary hemorrhage 2 days after the TAE. Although he responded well to a combination treatment with corticosteroid and cyclophosphamide, recurrence of pulmonary hemorrhage led to death, on the 87th hospital day. MPA in this patient was associated with three serious complications; deteriorating renal function, massive melena, and pulmonary hemorrhage. Of the various manifestations associated with MPA, arterial bleeding in the gastrointestinal tract, although rare, should be considered as one of the serious complications in MPA.

Effect of divalent cations on the ATPase activity of Escherichia coli SecA

It was found that Ca(2+) stimulates the intrinsic SecA ATPase activity in the absence as well as in the presence of liposome. On the other hand, Mg(2+), the general cofactor for ATPase, did not affect the intrinsic SecA ATPase but reduced the portion of ATPase activity enhanced by Ca(2+). The enhancement of SecA ATPase activity correlated well with the increase in 8-anilino-1-naphthalene-sulfonic acid binding of SecA, suggesting that increased exposure of hydrophobic residues stimulates the enzyme activity.

Influence of stent expansion states on platelet deposition in an extracorporeal porcine arteriovenous shunt model using a multichannel perfusion chamber

Limited data are available about incomplete stent expansion (SE) on platelet deposition (PD). We examined PD following different SE using an extracorporeal porcine arteriovenous shunt model to which a perfusion chamber with four parallel silastic tubes were connected. Blood flow was set at a 20 and 100 mL/min in 1.8 and 3.1 mm diameter tubes, respectively. P154 stents were deployed completely (Group A, n=15) or incompletely (Group B, n=15) in 1.8 mm (n=13) and 3.1 mm (n=17) tubes. 51Cr-labelled platelet autologous blood was injected 1 hr before the perfusion. After 15 min-perfusion, the testing tubes were assessed for radioactivity counts. In-stent cross sectional area was measured by intravascular ultrasound. There was a significant difference in PD between group A and B regardless of channel size (118+/-18.4 vs 261.4+/-52.1 pits x 10(6)/cm2, p<0.05). With adjusted shear rate and similar stenosis, PD was similar in both tubes. In smaller 1.8 mm tubes, a stenosis as subtle as 10% was associated with a significant PD difference (226.1+/-20 vs 112.9+/-20.5 plts x 10(6)/cm2, p<0.005). This model enabled a repetitive, simultaneous comparison of PD following different SE states. It seems that the quality of SE remains crucial in smaller channels.

Importance of phosphatidylethanolamine for the interaction of apocytochrome c with model membranes containing phosphatidylserine

The effect of phosphatidylethanolamine (PE) on the binding of apocytochrome c to model membranes was examined. When 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) of the standard vesicles composed of 80% of this lipid and 20% of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoserine (POPS) was gradually replaced with upward of 50% of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), the binding increased appreciably. Ca(2+), causing the phase separation of PS, also brought about increased binding of apocytochrome c in the PC/PS system, underlining the importance of PS properties in membranes for the protein binding. The resonance energy transfer between Trp-59 in apocytochrome c and pyrene-PS incorporated into bilayers showed that the replacement of PC with PE increased the extent of apocytochrome c penetration into membranes by a PE concentration-dependent manner. However, in the absence of PS, PE had no apparent effect on these functions of apocytochrome c, suggesting that PE-induced change(s) of acidic membrane properties is important to the association of apocytochrome c with vesicles. From the observations that the excimer to monomer fluorescence ratio of pyrene-PS increased and the fluorescence of NBD-PS was quenched with increasing concentration of PE, it was deduced that PE caused PS-enriched domains in PC/PE/PS membranes. The colocalization of pyrene-PS with BODIPY-PS by PE further supported the possibility. We suggest that PE-induced formation of PS-enriched domains acts as binding sites for apocytochrome c in membranes.

Phase properties of liquid-crystalline Phosphatidylcholine/Phosphatidylethanolamine bilayers revealed by fluorescent probes

The mixing properties of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were examined in liquid-crystalline phase using fluorescent probes incorporated into lipid bilayers. The excimer to monomer (E/M) fluorescence ratio of 1-hexadecanoyl-2-(1-pyrenedecanoyl)-sn-glycero-3-phosphocholine (PPC) versus PPC concentration was higher for binary mixtures containing phosphatidylcholine (PC)/phosphatidylethanolamine (PE) (1:1) compared to PC matrix. When POPC was gradually replaced with POPE, the E/M ratio also increased suggesting the enhanced lateral mobility or the lateral enrichment of PPC into domains or both. Evidences for the PE-induced domain formation were further provided by resonance energy transfer between 2-(4, 4-difluoro-5-methyl-4-boro-3a, 4a-diaza-s-indacene-3-dodecanoyl)-1-hexadecanoyl-sn-glycero- 3-phospho choline and PPC, which was enhanced as a function of PE concentration, and by the polarization of 1,6-diphenyl-1,3, 5-hexatriene. In addition, PE reduced free volume and polarity of lipid bilayers as measured by the emission fluorescence of 1,2-bis PPC and 6-lauroyl-2-dimethylaminonaphthalene. When POPE analogs with a methylated head group instead of normal POPE were used, the diminished effect on the domain formation was shown in the order N-methyl PE > N,N-dimethyl PE. The results suggest that the mixing properties of POPE and POPC are not random but that lipid domains of phospholipids are formed.

Molecular interactions in ribose transport: the binding protein module symmetrically associates with the homodimeric membrane transporter

The Escherichia coli high-affinity ribose transporter is composed of the periplasmic ribose-binding protein (RBP or RbsB), the membrane component (RbsC) and the ATP-binding protein (RbsA). In order to dissect the molecular interactions initiating the transport process, RbsC suppressors for transport-defective rbsB mutations were isolated. These suppressors are localized in two regions of RbsC, which are allele-specific to N- or C-terminal domain mutations of RBP, suggesting that there are two distinct regions of RbsC, each interacting with one of the two domains of RBP. To demonstrate that these two regions provide a homodimeric binding surface for RBP we constructed a dimeric rbsC in which two genes are joined tandemly from head to tail with the addition of a linker. The dimeric RbsC protein is stable and functional in growth and ribose uptake. By exploiting the allele specificity between the domain-specific mutations and their suppressors, we generated all mutation-suppressor combinations in a single rbsB plus the dimeric rbsC genes. Their phenotypes are consistent with the proposal that the binding protein module interacts symmetrically with homodimeric RbsC. The mode of association proposed here for the ribose transport components could be extended to other ABC transporters with similar structural organizations.

Phospholipase D activity of cytochrome P450 in human liver endoplasmic reticulum

Phospholipase D (PLD) activity in mammalian liver endoplasmic reticulum (ER) has not been characterized. Purified human liver microsomal cytochromes P450 (P450)-P450 1A2 and P450 2E1-were shown to have appreciable PLD activity, hydrolyzing phosphatidylcholine but not other phospholipids, generating PA and choline. The activity was confirmed using recombinant and mutated human P450s expressed in bacteria. In human liver microsomes, immunoinhibition of PLD activity was observed with anti-P450 1A2 > anti-P450 2C > anti-P450 2E1. Thus, P450 may act as a significant PLD in human liver ER and exert its biological effects by several mechanisms, including signaling functions and change of membrane properties.

[Diagnostic usefulness of magnetic resonance cholangiopancreatography (MRCP) in comparison with retrograde cholangiopancreatography (ERCP) for cholelithiasis]

PURPOSE

To elucidate MRCP diagnostic usefulness compared to ERCP.

PATIENTS, METHODS

29 MRCP performed patients diagnosed by ERCP were studied.

RESULTS

MRCP showed 92%, 67% sensitivity and 73%, 100% specificity in choledocholithiasis (CBD) and cholecystolithiasis (GB), respectively. MRCP revealed 4.0 false positive and 1.5 false negative in CBD and GB, respectively. MRCP could detect 22 stones out of 33 in CBD and 13 out of 42 in GB. As for the maximal diameter, MRCP depicted 31% for less than 5 mm and 100% for over 6 mm in CBD. In GB, 7% for less than 5 mm, 83% for 6-10 mm and 100% for over 11 mm.

CONCLUSION

Although the depection of tiny stone is limited, MRCP is a useful diagnostic tool for cholelithiasis, especially choledocholithiasis.

Membrane insertion of cytochrome P450 1A2 promoted by anionic phospholipids

The role of phospholipids in the membrane binding and subsequent insertion of the microsomal protein rabbit cytochrome P450 (P450) 1A2 into phospholipid bilayers was investigated. The insertion of P450 1A2 into phospholipid bilayers was measured by the quenching of Trp fluorescence of P450 1A2 by pyrene and brominated and doxyl-labeled phospholipids. When the phosphatidylcholine (PC) matrix was replaced with acidic phospholipids [phosphatidic acid (PA), phosphatidylserine, and phosphatidylinositol] and phosphatidylethanolamine (PE), the extent of insertion into lipid bilayers was strictly dependent on the type of acidic phospholipids. All anionic phospholipids caused the penetration of P450 1A2 into lipid bilayers, but PA was the most efficient in facilitating deep penetration of P450 1A2 into bilayers. On the other hand, binding of P450 1A2 to liposomes was increased by acidic phospholipids to the same degree regardless of the type of acidic phospholipids. PE was found to act as an inert matrix phospholipid, similar to PC, as it exerted very little effect on the insertion of P450 1A2 into lipid bilayers and the binding of P450 1A2 to membranes. It was also found that the phospholipid-dependent membrane insertion of P450 1A2 was associated with altered enzyme activity, increased alpha-helix content, and increased Trp fluorescence of P450 1A2. These results indicate that negative charges on the acidic phospholipids are important for the initial binding of P450 1A2 to membranes, but the penetration of P450 1A2 into lipid bilayers is regulated by the type of acidic phospholipids, and that phospholipid-dependent insertion of P450 1A2 is accompanied by a structural change of P450 1A2.

Phase separation in phosphatidylcholine/anionic phospholipid membranes in the liquid-crystalline state revealed with fluorescent probes

The mixing properties of anionic phospholipids such as phosphatidic acid (PA), phosphatidylserine (PS), and phosphatidylglycerol (PG) with phosphatidylcholine (PC) were examined in the liquid-crystalline state of membranes using extrinsic fluorescent probes incorporated into lipid bilayers. The excimer to monomer (E/M) fluorescence ratio of 1-hexadecanoyl-2-(1-pyrenedecanoyl)-sn-glycero-3-phosphocholine (PPC) was higher for the PA and PS matrices as compared to that for the PC matrix. When PC was replaced with PA or PS, the E/M ratio of PPC also increased in a concentration-dependent manner. When the concentration of PA or PS was increased in the PC membrane, the fluorescence of 1-palmitoyl-2-[12-[7-nitro-2,1, 3-benzodiazol-4-yl)amino]dodecanoyl]-sn-glycero-3-phosphocholine decreased, indicating the occurrence of lipid clustering. Direct evidence for the PA or PS-induced phase separation in the PC/PA or PC/PS system was provided by the resonance energy transfer between 2-(4,4-difluoro-5-methyl-4-boro-3a, 4a-diaza-s-indacene-3-dodecanoly)-1-hexadecanoly -sn-glycero-3-phospho choline and PPC. The fluorescence polarization of 1,6-diphenyl-1,3, 5-hexatriene further supported the lateral organization of membranes by PA and PS. PA and PS also reduced the polarity of lipid bilayers, as measured by the emission fluorescence of 6-lauroyl-2-dimethylaminonaphthalene. On the other hand, PG had very little effect on the PC matrix, suggesting the ideal miscibility with PC molecules. The results suggest that the mixing properties of PA and PS in the PC matrix are not random but that phase separation occurs in the liquid-crystalline phase of membranes.

Effects of nonlamellar-prone lipids on the ATPase activity of SecA bound to model membranes

The effect of nonlamellar-prone lipids, diacylglycerol (DG) and phosphatidylethanolamine (PE), on the ATPase activity of SecA was examined. When Escherichia coli PE of the standard vesicles composed of 60 mol% of this lipid and 40 mol% of dioleoylphosphatidylglycerol (DOPG) is gradually replaced with either dioleoylglycerol (DOG) or dioeloyl PE (DOPE), the ATPase activity of SecA present together increased appreciably. On the other hand, when E. coli PE of the standard vesicles was replaced with DOG analogs, the SecA ATPase activity decreased slightly, and when replaced with phosphatidylcholine the decrease in the ATPase activity was more appreciable. When DOPE or E. coli PE was added to PC vesicles, the SecA ATPase activity was enhanced only slightly, suggesting that the hexagonal II structure per se is not important for the ATPase activity increase. It was observed that DOG induced phase separation of PG, and the lamellar-hexagonal II (L-HII) transition temperature of vesicles decreased by about 10 degreesC. The DOG analogs had no effect on these properties, suggesting the importance of the phase separation of PG and the decrease of L-HII transition temperature of lipid bilayers to the SecA ATPase activity. The phase separation of PG by Ca2+ also brought about increased ATPase activity of SecA, underlining the importance of phase separation of PG for the enzyme activity. The incorporation of DOG or DOPE in the vesicle also increased the amount of SecA bound to model membranes and the extent of SecA penetration into the membrane. Studies with vesicles without SecA showed increased exposure of hydrophobic acyl chains when the DOG was present. Taken together, these observations suggest that the phase separation of PG and/or the bilayer penetration of SecA are mainly responsible for the enhanced SecA-vesicle interaction with concomitant increase in SecA ATPase activity.

Conformational change and activation of cytochrome P450 2B1 induced by salt and phospholipid

A stimulatory effect of increased salt concentration on the enzymatic activity of rat liver microsomes and a reconstituted system containing cytochrome P450 (P450) 2B1 and NADPH-P450 reductase was seen. Structural change of P450 2B1 accompanying the salt-induced increase in its enzyme activity was investigated by circular dichroism, fluorescence spectroscopy, and absorption spectroscopy. It was found that the salt increased alpha-helix content of P450 2B1 in the presence as well as in the absence of a phospholipid. Intrinsic fluorescence emissions also increased with increasing salt concentration. The low-spin iron configuration of P450 2B1 shifted toward the high-spin configuration in response to the increased salt concentration. It was found that the activity increase of P450 coincides with the raised alpha-helix content. The presence of phospholipid magnified this effect. It is proposed that the interaction with salts and phospholipid molecules surrounding P450 2B1 in the endoplasmic reticulum is important for a functional conformation of P450 2B1 in a monooxygenase system including NADPH-P450 reductase.

Hepatosplenic T-cell lymphoma: prolymphocytic transformation 18 months after splenectomy

We report a young woman with pancytopenia and huge splenomegaly who was also found to have peripheral T-cell lymphoma with massive infiltration of T-cell evident in the liver and spleen. A liver biopsy showed predominant sinusoidal infiltration of pan-T cell antibody-stained T-lymphoid cells. Histologic examination of the spleen revealed numerous tumor cells predominantly infiltrated in the cords and sinuses of the red pulp, which were identical to those described in the liver. Several clusters of small round abnormal cells were observed in marrow cytology. Although the patient felt well during 18 months after the splenectomy was done, the patient eventually manifested a huge hepatomegaly, showed increasing white blood cell count to 42 x 10(9)/l, and numerous prolymphocytes (66.9%) in the bone marrow. This change represented a prolymphocytic transformation of the patient's original hepatosplenic T-cell lymphoma.