Lanthanide ions (Eu3+, Er3+, Pr3+) as luminescence and charge carrier centers in Sr2TiO4

A series of strontium orthotitanate (Sr₂TiO₄) samples doped with 2% of a mole of europium, praseodymium, and erbium were obtained using the solid-state synthesis method. The X-ray diffraction (XRD) technique confirms the phase purity of all samples and the lack of the influence of dopants at a given concentration on the structure of materials. The optical properties indicate, in the case of Sr₂TiO₄:Eu³⁺, two independent emission (PL) and excitation (PLE) spectra attributed to the Eu³⁺ ions at sites with different symmetries: low - excited at 360 nm and high - excited at 325 nm, while, for Sr₂TiO₄:Er³⁺ and Sr₂TiO₄:Pr³⁺, the emission spectra do not depend on the excitation wavelength. The measurements of X-ray photoemission spectroscopy (XPS) indicate the presence of only one type of charge compensation mechanism, which is based on the creation of strontium vacancies in all cases. This suggests that the different charge compensation mechanisms cannot easily explain the presence of Eu³⁺ at two non-equivalent crystal sites. The photocurrent excitation (PCE) spectroscopy investigations, that have not been reported in the literature so far, show that among all the studied dopants, only Pr³⁺ can promote the electrons to the conduction band and give rise to electron conductivity. The results collected from the PLE and PCE spectra allowed us to find the location of the ground states of lanthanides(II)/(III) in the studied matrix.

Unraveling the Metabolic Derangements Occurring in Non-infarcted Areas of Pig Hearts With Chronic Heart Failure

Objective: After myocardial infarction (MI), the non-infarcted left ventricle (LV) ensures appropriate contractile function of the heart. Metabolic disturbance in this region greatly exacerbates post-MI heart failure (HF) pathology. This study aimed to provide a comprehensive understanding of the metabolic derangements occurring in the non-infarcted LV that could trigger cardiovascular deterioration. Methods and Results: We used a pig model that progressed into chronic HF over 3 months following MI induction. Integrated gene and metabolite signatures revealed region-specific perturbations in amino acid- and lipid metabolism, insulin signaling and, oxidative stress response. Remote LV, in particular, showed impaired glutamine and arginine metabolism, altered synthesis of lipids, glucose metabolism disorder, and increased insulin resistance. LPIN1, PPP1R3C, PTPN1, CREM, and NR0B2 were identified as the main effectors in metabolism dysregulation in the remote zone and were found differentially expressed also in the myocardium of patients with ischemic and/or dilated cardiomyopathy. In addition, a simultaneous significant decrease in arginine levels and altered PRCP, PTPN1, and ARF6 expression suggest alterations in vascular function in remote area. Conclusions: This study unravels an array of dysregulated genes and metabolites putatively involved in maladaptive metabolic and vascular remodeling in the non-infarcted myocardium and may contribute to the development of more precise therapies to mitigate progression of chronic HF post-MI.

Inhibition of sodium/hydrogen exchanger 3 in the gastrointestinal tract by tenapanor reduces paracellular phosphate permeability

Hyperphosphatemia is common in patients with chronic kidney disease and is increasingly associated with poor clinical outcomes. Current management of hyperphosphatemia with dietary restriction and oral phosphate binders often proves inadequate. Tenapanor, a minimally absorbed, small-molecule inhibitor of the sodium/hydrogen exchanger isoform 3 (NHE3), acts locally in the gastrointestinal tract to inhibit sodium absorption. Because tenapanor also reduces intestinal phosphate absorption, it may have potential as a therapy for hyperphosphatemia. We investigated the mechanism by which tenapanor reduces gastrointestinal phosphate uptake, using in vivo studies in rodents and translational experiments on human small intestinal stem cell-derived enteroid monolayers to model ion transport physiology. We found that tenapanor produces its effect by modulating tight junctions, which increases transepithelial electrical resistance (TEER) and reduces permeability to phosphate, reducing paracellular phosphate absorption. NHE3-deficient monolayers mimicked the phosphate phenotype of tenapanor treatment, and tenapanor did not affect TEER or phosphate flux in the absence of NHE3. Tenapanor also prevents active transcellular phosphate absorption compensation by decreasing the expression of NaPi2b, the major active intestinal phosphate transporter. In healthy human volunteers, tenapanor (15 mg, given twice daily for 4 days) increased stool phosphorus and decreased urinary phosphorus excretion. We determined that tenapanor reduces intestinal phosphate absorption predominantly through reduction of passive paracellular phosphate flux, an effect mediated exclusively via on-target NHE3 inhibition.

SGLT2 inhibition with empagliflozin improves coronary microvascular function and cardiac contractility in prediabetic ob/ob-/- mice

Background

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) is the first class of anti-diabetes treatment that reduces mortality and risk for hospitalization due to heart failure. In clinical studies it has been shown that SGLT2i’s promote a general shift to fasting state metabolism characterized by reduced body weight and blood glucose, increase in glucagon/insulin ratio and modest increase in blood ketone levels. Therefore, we investigated the connection between metabolic changes and cardiovascular function in the ob/ob^−/− mice; a rodent model of early diabetes with specific focus on coronary microvascular function. Due to leptin deficiency these mice develop metabolic syndrome/diabetes and hepatic steatosis. They also develop cardiac contractile and microvascular dysfunction and are thus a promising model for translational studies of cardiometabolic diseases. We investigated whether this mouse model responded in a human-like manner to empagliflozin treatment in terms of metabolic parameters and tested the hypothesis that it could exert direct effects on coronary microvascular function and contractile performance.

Methods

Lean, ob/ob^−/− untreated and ob/ob^−/− treated with SGLT2i were followed for 10 weeks. Coronary flow velocity reserve (CFVR) and fractional area change (FAC) were monitored with non-invasive Doppler ultrasound imaging. Food intake, urinary glucose excursion and glucose control via HbA1c measurements were followed throughout the study. Liver steatosis was assessed by histology and metabolic parameters determined at the end of the study.

Results

Sodium-glucose cotransporter 2 inhibitors treatment of ob/ob^−/− animals resulted in a switch to a more catabolic state as observed in clinical studies: blood cholesterol and HbA1c were decreased whereas glucagon/insulin ratio and ketone levels were increased. SGLT2i treatment reduced liver triglyceride, steatosis and alanine aminotransferase, an indicator for liver dysfunction. l-Arginine/ADMA ratio, a marker for endothelial function was increased. SGLT2i treatment improved both cardiac contractile function and coronary microvascular function as indicated by improvement of FAC and CFVR, respectively.

Conclusions

Sodium-glucose cotransporter 2 inhibitors treatment of ob/ob^−/− mice mimics major clinical findings regarding metabolism and cardiovascular improvements and is thus a useful translational model. We demonstrate that SGLT2 inhibition improves coronary microvascular function and contractile performance, two measures with strong predictive values in humans for CV outcome, alongside with the known metabolic changes in a preclinical model for prediabetes and heart failure.

The APOE∗3-Leiden Heterozygous Glucokinase Knockout Mouse as Novel Translational Disease Model for Type 2 Diabetes, Dyslipidemia, and Diabetic Atherosclerosis

BACKGROUND

There is a lack of predictive preclinical animal models combining atherosclerosis and type 2 diabetes. APOE∗3-Leiden (E3L) mice are a well-established model for diet-induced hyperlipidemia and atherosclerosis, and glucokinase^+/- (GK^+/-) mice are a translatable disease model for glucose control in type 2 diabetes. The respective mice respond similarly to lipid-lowering and antidiabetic drugs as humans. The objective of this study was to evaluate/characterize the APOE^∗3-Leiden.glucokinase^+/- (E3L.GK^+/-) mouse as a novel disease model to study the metabolic syndrome and diabetic complications.

METHODS

Female E3L.GK^+/-, E3L, and GK^+/- mice were fed fat- and cholesterol-containing diets for 37 weeks, and plasma parameters were measured throughout. Development of diabetic macro- and microvascular complications was evaluated.

RESULTS

Cholesterol and triglyceride levels were significantly elevated in E3L and E3L.GK^+/- mice compared to GK^+/- mice, whereas fasting glucose was significantly increased in E3L.GK^+/- and GK^+/- mice compared to E3L. Atherosclerotic lesion size was increased 2.2-fold in E3L.GK^+/- mice as compared to E3L (p = 0.037), which was predicted by glucose exposure (R ² = 0.636, p = 0.001). E3L and E3L.GK^+/- mice developed NASH with severe inflammation and fibrosis which, however, was not altered by introduction of the defective GK phenotype, whereas mild kidney pathology with tubular vacuolization was present in all three phenotypes.

CONCLUSIONS

We conclude that the E3L.GK^+/- mouse is a promising novel diet-inducible disease model for investigation of the etiology and evaluation of drug treatment on diabetic atherosclerosis.

Ultrafast Formation of a Fermi-Dirac Distributed Electron Gas

Time- and angle-resolved photoelectron spectroscopy with 13 fs temporal resolution is used to follow the different stages in the formation of a Fermi-Dirac distributed electron gas in graphite after absorption of an intense 7 fs laser pulse. Within the first 50 fs after excitation, a sequence of time frames is resolved that are characterized by different energy and momentum exchange processes among the involved photonic, electronic, and phononic degrees of freedom. The results reveal experimentally the complexity of the transition from a nascent nonthermal towards a thermal electron distribution due to the different timescales associated with the involved interaction processes.

Hyperglycemia Induced by Glucokinase Deficiency Accelerates Atherosclerosis Development and Impairs Lesion Regression in Combined Heterozygous Glucokinase and the Apolipoprotein E-Knockout Mice

Aim. Models combining diabetes and atherosclerosis are important in evaluating the cardiovascular (CV) effects and safety of antidiabetes drugs in the development of treatments targeting CV complications. Our aim was to evaluate if crossing the heterozygous glucokinase knockout mouse (GK+/-) and hyperlipidemic mouse deficient in apolipoprotein E (ApoE-/-) will generate a disease model exhibiting a diabetic and macrovascular phenotype. Methods. The effects of defective glucokinase on the glucose metabolism and on the progression and regression of atherosclerosis on high-fat diets were studied in both genders of GK+/-ApoE-/- and ApoE-/- mice. Coronary vascular function of the female GK+/-ApoE-/- and ApoE-/- mice was also investigated. Results. GK+/-ApoE-/- mice show a stable hyperglycemia which was increased on Western diet. In oral glucose tolerance test, GK+/-ApoE-/- mice showed significant glucose intolerance and impaired glucose-stimulated insulin secretion. Plasma lipids were comparable with ApoE-/- mice; nevertheless the GK+/-ApoE-/- mice showed slightly increased atherosclerosis development. Conclusions. The GK+/-ApoE-/- mice showed a stable and reproducible hyperglycemia, accelerated atherosclerotic lesion progression, and no lesion regression after lipid lowering. This novel model provides a promising tool for drug discovery, enabling the evaluation of compound effects against both diabetic and cardiovascular endpoints simultaneously in one animal model.

Spectroscopic properties and location of the Tb3+ and Eu3+ energy levels in Y2O2S under high hydrostatic pressure

In this contribution, an extensive spectroscopic study of Y₂O₂S doped with Eu³⁺ and Tb³⁺ is presented.

Increased Arterial Blood Pressure and Vascular Remodeling in Mice Lacking Salt-Inducible Kinase 1 (SIK1)

Rationale:

In human genetic studies a single nucleotide polymorphism within the salt-inducible kinase 1 ( SIK1 ) gene was associated with hypertension. Lower SIK1 activity in vascular smooth muscle cells (VSMCs) leads to decreased sodium-potassium ATPase activity, which associates with increased vascular tone. Also, SIK1 participates in a negative feedback mechanism on the transforming growth factor-β1 signaling and downregulation of SIK1 induces the expression of extracellular matrix remodeling genes.

Objective:

To evaluate whether reduced expression/activity of SIK1 alone or in combination with elevated salt intake could modify the structure and function of the vasculature, leading to higher blood pressure.

Methods and Results:

SIK1 knockout ( sik1 −/− ) and wild-type ( sik1 +/+ ) mice were challenged to a normal- or chronic high-salt intake (1% NaCl). Under normal-salt conditions, the sik1 −/− mice showed increased collagen deposition in the aorta but similar blood pressure compared with the sik1 +/+ mice. During high-salt intake, the sik1 +/+ mice exhibited an increase in SIK1 expression in the VSMCs layer of the aorta, whereas the sik1 −/− mice exhibited upregulated transforming growth factor-β1 signaling and increased expression of endothelin-1 and genes involved in VSMC contraction, higher systolic blood pressure, and signs of cardiac hypertrophy. In vitro knockdown of SIK1 induced upregulation of collagen in aortic adventitial fibroblasts and enhanced the expression of contractile markers and of endothelin-1 in VSMCs.

Conclusions:

Vascular SIK1 activation might represent a novel mechanism involved in the prevention of high blood pressure development triggered by high-salt intake through the modulation of the contractile phenotype of VSMCs via transforming growth factor-β1-signaling inhibition.

Structural requirements of steroidal agonists of transient receptor potential melastatin 3 (TRPM3) cation channels

Background and Purpose

Transient receptor potential melastatin 3 (TRPM3) proteins form non-selective but calcium-permeable membrane channels, rapidly activated by extracellular application of the steroid pregnenolone sulphate and the dihydropyridine nifedipine. Our aim was to characterize the steroid binding site by analysing the structural chemical requirements for TRPM3 activation.

Experimental Approach

Whole-cell patch-clamp recordings and measurements of intracellular calcium concentrations were performed on HEK293 cells transfected with TRPM3 (or untransfected controls) during superfusion with pharmacological substances.

Key Results

Pregnenolone sulphate and nifedipine activated TRPM3 channels supra-additively over a wide concentration range. Other dihydropyridines inhibited TRPM3 channels. The natural enantiomer of pregnenolone sulphate was more efficient in activating TRPM3 channels than its synthetic mirror image. However, both enantiomers exerted very similar inhibitory effects on proton-activated outwardly rectifying anion channels. Epiallopregnanolone sulphate activated TRPM3 almost equally as well as pregnenolone sulphate. Exchanging the sulphate for other chemical moieties showed that a negative charge at this position is required for activating TRPM3 channels.

Conclusions and Implications

Our data demonstrate that nifedipine and pregnenolone sulphate act at different binding sites when activating TRPM3. The latter activates TRPM3 by binding to a chiral and thus proteinaceous binding site, as inferred from the differential effects of the enantiomers. The double bond between position C5 and C6 of pregnenolone sulphate is not strictly necessary for the activation of TRPM3 channels, but a negative charge at position C3 of the steroid is highly important. These results provide a solid basis for understanding mechanistically the rapid chemical activation of TRPM3 channels.

Expression of type IIA secretory phospholipase A2 inhibits cholesteryl ester transfer protein activity in transgenic mice

OBJECTIVE

High circulating levels of group IIA secretory phospholipase A2 (sPLA2-IIA) activity and mass are independent cardiovascular risk factors. Therefore, inhibition of sPLA2-IIA may be a target for the treatment of atherosclerotic cardiovascular disease. The present study evaluated the effects of sPLA2-IIA inhibition with varespladib acid in a novel mouse model, human apolipoprotein B (apoB)/human cholesteryl ester transfer protein (CETP)/human sPLA2-IIA triple transgenic mice (TTT) fed a Western-type diet.

APPROACH AND RESULTS

sPLA2-IIA expression increased atherosclerotic lesion formation in TTT compared with human apoB/human CETP double transgenic mice (P<0.01). Varespladib acid effectively inhibited plasma sPLA2-IIA activity. Surprisingly, however, administration of varespladib acid to TTT had no impact on atherosclerosis, which could be attributed to a proatherogenic plasma lipoprotein profile that appears in response to sPLA2-IIA inhibition because of increased plasma CETP activity. In the TTT model, sPLA2-IIA decreased CETP activity by reducing the acceptor properties of sPLA2-IIA-modified very low-density lipoproteins specifically because of a significantly lower apoE content. Increasing very low-density lipoprotein-apoE content by means of adenovirus-mediated gene transfer in sPLA2-IIA transgenic mice restored the acceptor properties for CETP.

CONCLUSIONS

These data show that in a humanized triple transgenic mouse model with hypercholesterolemia, sPLA2-IIA inhibition increases CETP activity via increasing the very low-density lipoprotein-apoE content, resulting in a proatherogenic lipoprotein profile.

High pressure luminescence spectra of CaMoO4:Ln3+ (Ln = Pr, Tb)

Photoluminescence spectra and luminescence kinetics of pure CaMoO(4) and CaMoO(4) doped with Ln(3+) (Ln = Pr or Tb) are presented. The spectra were obtained at high hydrostatic pressure up to 240 kbar applied in a diamond anvil cell. At ambient pressure undoped and doped samples exhibit a broad band emission extending between 380 and 700 nm with a maximum at 520 nm attributed to the MoO(4)(2-) luminescence. CaMoO(4) doped with Pr(3+) or Tb(3+) additionally yields narrow emission lines related to f-f transitions. The undoped CaMoO(4) crystal was characterized by a strong MoO(4)(2-) emission up to 240 kbar. In the cases of CaMoO(4):Pr(3+) and CaMoO(4):Tb(3+), high hydrostatic pressure caused quenching of Pr(3+) and Tb(3+) emission, and this effect was accompanied by a strong shortening of the luminescence lifetime. In doped samples, CaMoO(4):Pr(3+) and CaMoO(4):Tb(3+), quenching of the emission band attributed to MoO(4)(2-) was also observed, and at pressure above 130 kbar this luminescence was totally quenched. The effects mentioned above were related to the influence of the praseodymium (terbium) trapped exciton PTE (ITE-impurity trapped exciton) on the efficiency of the Pr(3+) (Tb(3+)) and MoO(4)(2-) emissions.

Effects of rosuvastatin on cardiovascular morphology and function in an ApoE-knockout mouse model of atherosclerosis

This study investigated the effects of rosuvastatin on plaque progression and in vivo coronary artery function in apolipoprotein E-knockout (ApoE-KO) mice, using noninvasive high-resolution ultrasound techniques. Eight-week-old male ApoE-KO mice (n = 20) were fed a high-fat diet with or without rosuvastatin (10 micromol.kg(-1).day(-1)) for 16 wk. When compared with control, rosuvastatin reduced total cholesterol levels (P < 0.05) and caused significant retardation of lesion progression in the brachiocephalic artery, as visualized in vivo using an ultrasound biomicroscope (P < 0.05). Histological analysis confirmed the reduction of brachiocephalic atherosclerosis and also revealed an increase in collagen content in the statin-treated group (P < 0.05). Coronary volumetric flow was measured by simultaneous recording of Doppler velocity signals and left coronary artery morphology before and during adenosine infusion. The hyperemic flow in response to adenosine was significantly greater in left coronary artery following 16 wk of rosuvastatin treatment (P < 0.001), whereas the baseline flow was similar in both groups. In conclusion, rosuvastatin reduced brachiocephalic artery atherosclerotic plaques in ApoE-KO mice. Coronary artery function assessed using recently developed in vivo ultrasound-based protocols, also improved.

Human TIEG2/KLF11 induces oligodendroglial cell death by downregulation of Bcl-XL expression

TGF-beta-induced apoptosis is essential for embryonic development and mainteanance of adult tissues. Impairment of the apoptotic pathway, regulated by TGF-beta, plays a center role in tumorigenesis and manifestations of different diseases. TIEG2/KLF11 is a recently identified human TGF-beta-inducible zinc finger protein belonging to the family of Sp1/KLF-like transcription factors. In human and murine tissues it has been shown that TIEG1 and TIEG2 induce apoptosis and inhibit cell growth. Since TGF-beta and Tieg1 are able to induce apoptosis in the oligodendroglial cell line OLI-neu, we analysed the ability of TIEG2 to mimic the effects observed after treatment with TGF-beta and overexpression of Tieg1. Herein we report that TIEG2 induces Caspase3-dependent apoptosis in murine OLI-neu cells. Furthermore, we could demonstrate that TIEG2 decreases the levels of the anti-apoptotic protein Bcl-X(L) and inhibits transcription driven by the Bcl-X(L) promoter. These data suggest that TIEG2 serves as a downstream mediator of TGF-beta, bridging TGF-beta-dependent signaling to the intracellular pathway of apoptosis.

Effect of broad-spectrum matrix metalloproteinase inhibition on atherosclerotic plaque stability

OBJECTIVE

Matrix metalloproteinases (MMPs) form a large family of enzymes that collectively can degrade all components of the extracellular matrix, and there is widespread interest in developing MMP inhibitors for the prevention of atherosclerotic plaque rupture. We have therefore investigated the effects of a broad-spectrum MMP inhibitor, RS-130830, on plaque development and stability. This compound inhibits a wide range of MMPs at concentrations below 20 nmol/L.

METHODS

Apolipoprotein E knockout mice were fed a Western diet. Dietary administration of RS-130830 commenced at the same time as fat-feeding and continued for 8, 12, 26 or 36 weeks. To investigate the effect of RS-130830 on established plaques, mice were fed high-fat diet for 16 weeks before initiation of drug treatment and were terminated 20 weeks after this.

RESULTS

Broad-spectrum MMP inhibition was associated with a significant increase in plaque area, but there was no change in the incidence of plaque rupture. There were unfavourable changes in phenotypic characteristics associated with plaque instability, such as an increased lipid content and decreased collagen content.

CONCLUSIONS

These data suggest that broad-spectrum MMP inhibition RS-130830 does not have a beneficial effect on atherosclerosis in the apolipoprotein E knockout mouse model, and indicate that more selective compounds would be preferable.

Balance of pro-apoptotic transforming growth factor-β and anti-apoptotic insulin effects in the control of cell death in the postnatal mouse retina

Transforming growth factor (TGF)-beta and insulin display opposite effects in regulating programmed cell death during vertebrate retina development; the former induces apoptosis while the latter prevents it. In the present study we investigated coordinated actions of TGF-beta and insulin in an organotypic culture system of early postnatal mouse retina. Addition of exogenous TGF-beta resulted in a significant increase in cell death whereas exogenous insulin attenuated apoptosis and was capable of blocking TGF-beta-induced apoptosis. This effect appeared to be modulated via insulin-induced transcriptional down-regulation of TGF-beta receptor II levels. The analysis of downstream signalling molecules also revealed opposite effects of both factors; insulin provided survival signalling by increasing the level of anti-apoptotic Bcl-2 protein expression and phosphorylation and down-regulating caspase 3 activity whereas pro-apoptotic TGF-beta signalling reduced Bcl-2 mRNA levels and Bcl-2 phosphorylation and induced the expression of TGF-induced immediate-early gene (TIEG), a Krüppel-like zinc-finger transcription factor, mimicking TGF-beta activity.

Role of ADAMTS-1 in atherosclerosis: remodeling of carotid artery, immunohistochemistry, and proteolysis of versican

OBJECTIVE

We investigated the potential role of ADAMTS-1 (a disintegrin and metalloprotease with thrombospondin motif type I) in atherogenesis.

METHODS AND RESULTS

ADAMTS-1 is expressed at the highest levels in the aorta when compared with other human tissues examined. Immunolocalization studies in human aorta and coronary artery indicate that ADAMTS-1 expression is mainly seen at low levels in the medial layer, but upregulated in the intima when plaque is present. We found that ADAMTS-1 mRNA levels are significantly higher in proliferating/migrating cultured primary aortic vascular smooth muscle cells (VSMCs) compared with resting/confluent cells. Using the mouse carotid artery flow cessation model, we show that there are differences in vessel remodeling in ADAMTS-1 transgenic/apoE-deficient mice compared with apoE deficiency alone, particularly a significant increase in intimal hyperplasia. We show that ADAMTS-1 can cleave the large versican containing proteoglycan population purified from cultured human aortic VSMCs. Finally, using versican peptide substrates, we show data suggesting that ADAMTS-1 cleaves versican at multiple sites.

CONCLUSIONS

We hypothesize that ADAMTS-1 may promote atherogenesis by cleaving extracellular matrix proteins such as versican and promoting VSMC migration.

The role of somatic mutation in determining the affinity of anti-DNA antibodies

Combinatorial antibody libraries were constructed from the spleen of a patient with concomitant systemic lupus erythematosus and idiopathic thrombocytopenia. Following selection of the libraries with DNA, a panel of 15 anti-DNA Fabs was isolated. Sequence analysis of these antibodies coupled with measurements of their affinities for ss- and dsDNA were used to investigate the role of somatic mutation in affinity maturation of the anti-DNA response. Examination of the germline genes used by these Fabs supports previous studies that suggest there is no restriction of the gene usage in the anti-DNA response. However, data are presented indicating that VH3 genes and the A27 V(kappa) paired with the J(kappa)1 may be over-expressed in the anti-DNA repertoire. Analysis of the role of somatic mutation in increasing affinity for DNA indicates that affinity maturation has occurred and suggests that the CDR1 and CDR2 of the heavy chain are of importance in this process.

Translocation, deletion/amplification, and expression of HMGIC and MDM2 in a carcinoma ex pleomorphic adenoma

Carcinoma ex pleomorphic adenoma (CexPA) is a carcinoma developing within a pre-existing benign pleomorphic adenoma (PA). Here we describe the identification and characterization of a series of genetic events leading to translocation, deletion/amplification, and overexpression of the HMGIC and MDM2 genes in a CexPA at an early stage of development. The tumor had a pseudodiploid stemline karyotype with a del(5)(q22-23q32-33) and a t(10;12)(p15;q14-15). In addition, there were several sidelines with double minute chromosomes (dmin) or homogeneously staining regions (hsr). Fluorescence in situ hybridization (FISH) mapping revealed that the 12q14-15 breakpoint was located centromeric to HMGIC and that the entire gene was juxtaposed to the der(10) chromosome. Detailed analysis of cells with dmin and hsr revealed that HMGIC and MDM2 were deleted from the der(10) and that the dmin and hsr were strongly positive for both genes. Southern blot analysis confirmed that both HMGIC and MDM2 were amplified and that no gross rearrangements of the genes had occurred. Immunostaining revealed that the HMGIC protein was highly overexpressed particularly in the large polymorphic cells within the carcinomatous part of the tumor. These findings suggest that amplification and overexpression of HMGIC and possibly MDM2 might be important genetic events that may contribute to malignant transformation of benign PA.

Multicolor spectral karyotype analysis of a transplantable human ileal carcinoid

In this report we present the results of a combined cytogenetic and multicolor spectral karyotype (SKY) analysis of a transplantable human ileal carcinoid (GOT1). By using SKY it was possible to identify the origin and organization of all clonal marker chromosomes and to identify cryptic translocations not detectable by conventional chromosome banding. The stemline karyotype of low passage GOT1 cells was interpreted as 43,XX, der(1)del(1)(?), inv(2)(p25q13), del(3)(p21), del(5)(q13q31), del(6)(q13), -9, -13, -15, del(16) (q22). Analysis of the GOT1 cells after about 2.5 years of propagation in nude mice allowed us to follow the in vivo progression of this tumor. Relatively few additional rearrangements had occurred during this period, indicating that the GOT1 cells are genetically stable. Most of the abnormalities detected result in loss of whole or parts of chromosomes, suggesting that loss of multiple chromosomal regions, presumably containing tumor suppressor genes, might be important genetic events in ileal carcinoids.

The identification of endothelial cell autoantigens

The identity of many endothelial cell autoantigens remains unclear. This study has used human monoclonal anti-endothelial cell autoantibodies isolated from patients with SLE to identify endothelial autoantigens. Thirteen antibodies reactive with endothelial cell membrane preparations were isolated and cloned, one of which has previously been demonstrated to be pro-inflammatory. Western blotting demonstrates that these antibodies recognize a variety of proteins in endothelial cell membrane preparations. Further characterization of five antibodies by cDNA library screening, immunofluorescence and Western blotting proves that two of these antibodies recognized the cytoskeletal proteins tubulin and vimentin. A further antibody identified a clone derived from human collagenase, an identification supported by Western blotting. The multiple clones selected by other antibodies are not compatible with the molecular weight of the antigen recognized in Western blotting studies. This study has clearly identified two endothelial cell autoantigens present in membrane preparations and provides strong evidence as to the identity of a third.

Expression and mutation patterns of p53 in benign and malignant salivary gland tumors

The expression and mutation patterns of p53 were studied in a series of 68 benign pleomorphic adenomas and 237 malignant salivary gland tumors. p53 overexpression (nuclear staining exceeding 10%) was detected in 20% of the malignant salivary gland tumors, with the highest prevalence observed in polymorphous low grade adenocarcinoma, squamous cell carcinoma, and carcinoma ex pleomorphic adenoma and the lowest in adenoid cystic carcinoma and acinic cell carcinoma. In contrast, none of the 68 benign pleomorphic adenomas had nuclear staining exceeding 10%. SSCP and nucleotide sequence analysis of exons 4 to 9 of p53 in 19 malignant tumors revealed 9 mutations in 7 tumors. Our findings indicate that p53 may be a useful marker to help discriminate between benign and malignant salivary gland tumors.

Density and molecular epidemiology of Aspergillus in air and relationship to outbreaks of Aspergillus infection

After five patients were diagnosed with nosocomial invasive aspergillosis caused by Aspergillus fumigatus and A. flavus, a 14-month surveillance program for pathogenic and nonpathogenic fungal conidia in the air within and outside the University Hospital in Rotterdam (The Netherlands) was begun. A. fumigatus isolates obtained from the Department of Hematology were studied for genetic relatedness by randomly amplified polymorphic DNA (RAPD) analysis. This was repeated with A. fumigatus isolates contaminating culture media in the microbiology laboratory. The density of the conidia of nonpathogenic fungi in the outside air showed a seasonal variation: higher densities were measured during the summer, while lower densities were determined during the fall and winter. Hardly any variation was found in the numbers of Aspergillus conidia. We found decreasing numbers of conidia when comparing air from outside the hospital to that inside the hospital and when comparing open areas within the hospital to the closed department of hematology. The increase in the number of patients with invasive aspergillosis could not be explained by an increase in the number of Aspergillus conidia in the outside air. The short-term presence of A. flavus can only be explained by the presence of a point source, which was probably patient related. Genotyping A. fumigatus isolates from the department of hematology showed that clonally related isolates were persistently present for more than 1 year. Clinical isolates of A. fumigatus obtained during the outbreak period were different from these persistent clones. A. fumigatus isolates contaminating culture media were all genotypically identical, indicating a causative point source. Knowledge of the epidemiology of Aspergillus species is necessary for the development of strategies to prevent invasive aspergillosis. RAPD fingerprinting of Aspergillus isolates can help to determine the cause of an outbreak of invasive aspergillosis.

Fluorescence in situ hybridization mapping of breakpoints in pleomorphic adenomas with 8q12-13 abnormalities identifies a subgroup of tumors without PLAG1 involvement

Recently, we identified the PLAG1 gene as the target gene in pleomorphic adenomas with chromosome abnormalities involving 8q12. The majority of breakpoints were shown to reside within the 5' noncoding region of the gene. We now report three pleomorphic adenomas with breakpoints located distal to PLAG1 in band 8q13. These tumors had the following chromosome 8 abnormalities: ins(8;12)(q12-13;q14q15), t(8;12)(q13;q15), and t(6;8)(p21.3-22;q13). Fluorescence in situ hybridization mapping of the chromosome 8 breakpoints revealed a yeast artificial chromosome clone spanning the breakpoints in two tumors. In none of the cases was PLAG1 activated and/or disrupted. Three candidate genes, N8, HMGIC, and HMGIY, were analyzed for rearrangements and/or abnormal expression by using reverse transcriptase-polymerase chain reaction, rapid amplification of 3' cDNA ends, and Northern blot analyses.

Does the CDR3 of the heavy chain determine the specificity of autoantibodies in systemic lupus erythematosus?

Many factors are involved in the recognition of autoantigens by autoanti-bodies, including the use of specific germline genes, the sequence and structure of the CDR3 of the heavy chain, somatic mutation and selective heavy and light chain pairing. However, the relative importance of these factors remainsunclear. This study reports the results of sequence analysis of two anti-endothelial cell antibodies that recognise the same antigen. Sequence analysis of these antibodies shows that they use the same heavy chain germline genes as two anti-DNA antibodies but differ significantly in the sequence of the CDR3. Furthermore, one of the antibodies uses a light chain germline gene combination that has been reported for three anti-DNA antibodies. One of these antibodies shows significant mutation in the CDR2 of the heavy chain. Peptide analysis suggests that the differences between these anti-DNA and anti-endothelial cell antibodies result in consistent structural differences that may reflect the nature of the antigen recognised.

[Frequency of human papillomavirus-herpes simplex-cytomegalovirus and Chlamydia trachomatis infection in genital tracts of sexual partners]

OBJECTIVES

Much attention is given nowadays to the role of Human Papillomavirus, Herpes simplex virus, Cytomegalovirus, and Chlamydia trachomatis--infections in cervical carcinogenesis. Cytomegalovirus, Herpes simplex and Chlamydia trachomatis are now thought to be teratogenic to humans.

DESIGN

We investigated the prevalence of HPV, HSV, CMV and Chlamydia trachomatis in genital tracts of sexual partners.

MATERIALS AND METHODS

90 sexual partners were qualified for the research. Examination smears were taken with the dacron swab from the vaginal part of the uterine cervix, cervical canal, the lower vagina from women and from fossa navicularis penis in men. In the group of 67 men we have investigated semen as well. HPV, HSV, CMV and Chlamydia trachomatis were identified using PCR (Polymerse Chain Reaction)--method.

RESULTS AND CONCLUSIONS

In 48% of investigated sexual partners we proved the presence of Human Papillomavirus, in 2.2% of women and 2.9% of men--Cytomegalovirus and in 11.1% of women and 14.9% of men--Chlamydia trachomatis. In the investigated biological material we did not find any HSV infection.

Reduced beta-endorphin secretion in young patients with mild essential hypertension at rest and during exercise

Evidence suggests that altered central adrenergic and opioidergic activities are involved in the elevated blood pressure of patients with essential hypertension. In the present study plasma concentrations of the opioid peptide beta-endorphin were significantly lower at rest in young subjects with essential hypertension and high plasma noradrenaline (n = 9) than in normotensive controls (n = 13, P less than 0.05). After bicycle exercise the beta-endorphin of both groups increased comparably, the percentage increase being greater in essential hypertensives than in controls. Treatment with clonidine for 14 days normalized low beta-endorphin, high plasma noradrenaline and high blood pressure in essential hypertensives at rest, but had no effect in controls. After bicycle exercise clonidine induced a threefold greater increase in beta-endorphin in controls than in essential hypertensives. The results point to a reduced endorphinergic activity in essential hypertensives, both at rest and during exercise, which can be normalized by central alpha 2-agonism at rest only. The results may indicate altered interactions between central adrenergic and opioidergic receptor systems, which could contribute to high blood pressure in essential hypertensives.