Circular RNA circZFPM2 regulates cardiomyocyte hypertrophy and survival

Hypertrophic cardiomyopathy (HCM) constitutes the most common genetic cardiac disorder. However, current pharmacotherapeutics are mainly symptomatic and only partially address underlying molecular mechanisms. Circular RNAs (circRNAs) are a recently discovered class of non-coding RNAs and emerged as specific and powerful regulators of cellular functions. By performing global circRNA-specific next generation sequencing in cardiac tissue of patients with hypertrophic cardiomyopathy compared to healthy donors, we identified circZFPM2 (hsa_circ_0003380). CircZFPM2, which derives from the ZFPM2 gene locus, is a highly conserved regulatory circRNA that is strongly induced in HCM tissue. In vitro loss-of-function experiments were performed in neonatal rat cardiomyocytes, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), and HCM-patient-derived hiPSC-CMs. A knockdown of circZFPM2 was found to induce cardiomyocyte hypertrophy and compromise mitochondrial respiration, leading to an increased production of reactive oxygen species and apoptosis. In contrast, delivery of recombinant circZFPM2, packaged in lipid-nanoparticles or using AAV-based overexpression, rescued cardiomyocyte hypertrophic gene expression and promoted cell survival. Additionally, HCM-derived cardiac organoids exhibited improved contractility upon CM-specific overexpression of circZFPM2. Multi-Omics analysis further promoted our hypothesis, showing beneficial effects of circZFPM2 on cardiac contractility and mitochondrial function. Collectively, our data highlight that circZFPM2 serves as a promising target for the treatment of cardiac hypertrophy including HCM.

SARS-CoV-2 receptor ACE2-dependent implications on the cardiovascular system: From basic science to clinical implications

The current COVID-19 pandemic started several months ago and is still exponentially growing in most parts of the world - this is the most recent and alarming update. COVID-19 requires the collaboration of nearly 200 countries to curb the spread of SARS-CoV-2 while gaining time to explore and improve treatment options especially for cardiovascular disease (CVD) and immunocompromised patients, who appear to be at high-risk to die from cardiopulmonary failure. Currently unanswered questions are why elderly people, particularly those with pre-existing comorbidities seem to exhibit higher mortality rates after SARS-CoV-2 infection and whether intensive care becomes indispensable for these patients to prevent multi-organ failure and sudden death. To face these challenges, we here summarize the molecular insights into viral infection mechanisms and implications for cardiovascular disease. Since the infection starts in the upper respiratory system, first flu-like symptoms develop that spread throughout the body. The wide range of affected organs is presumably based on the common expression of the major SARS-CoV-2 entry-receptor angiotensin-converting enzyme 2 (ACE2). Physiologically, ACE2 degrades angiotensin II, the master regulator of the renin-angiotensin-aldosterone system (RAAS), thereby converting it into vasodilatory molecules, which have well-documented cardio-protective effects. Thus, RAAS inhibitors, which may increase the expression levels of ACE2, are commonly used for the treatment of hypertension and CVD. This, and the fact that SARS-CoV-2 hijacks ACE2 for cell-entry, have spurred controversial discussions on the role of ACE2 in COVID-19 patients. In this review, we highlight the state-of-the-art knowledge on SARS-CoV-2-dependent mechanisms and the potential interaction with ACE2 expression and cell surface localization. We aim to provide a list of potential treatment options and a better understanding of why CVD is a high risk factor for COVID-19 susceptibility and further discuss the acute as well as long-term cardiac consequences.

Regulatory T Cells Know What Is Needed to Regenerate

Adaptive immunity has been suggested to limit regeneration in mammals. However, in this issue of Developmental Cell, Hui et al. (2017) report that regulatory T cells are required for regeneration of heart, spinal cord, and retina in the zebrafish. Intriguingly, in each organ system, T_reg cells secrete organ-specific regeneration factors.

Single-molecule imaging correlates decreasing nuclear volume with increasing TF-chromatin associations during zebrafish development

Zygotic genome activation (ZGA), the onset of transcription after initial quiescence, is a major developmental step in many species, which occurs after ten cell divisions in zebrafish embryos. How transcription factor (TF)-chromatin interactions evolve during early development to support ZGA is largely unknown. We establish single molecule tracking in live developing zebrafish embryos using reflected light-sheet microscopy to visualize two fluorescently labeled TF species, mEos2-TBP and mEos2-Sox19b. We further develop a data acquisition and analysis scheme to extract quantitative information on binding kinetics and bound fractions during fast cell cycles. The chromatin-bound fraction of both TFs increases during early development, as expected from a physical model of TF-chromatin interactions including a decreasing nuclear volume and increasing DNA accessibility. For Sox19b, data suggests the increase is mainly due to the shrinking nucleus. Our single molecule approach provides quantitative insight into changes of TF-chromatin associations during the developmental period embracing ZGA.

Zebrafish fin and heart: what's special about regeneration?

Many organs regenerate well in adult zebrafish, but most research has been directed toward fin and heart regeneration. Cells have been found to remain generally lineage-restricted during regeneration, and proliferative regenerative progenitors can be formed by dedifferentiation from differentiated cells. Recent studies begin to shed light on the molecular underpinnings of differences between development and regeneration. Retinoic acid, BMP and NF-κB signaling are emerging as regulators of cellular dedifferentiation. Reactive oxygen species promote regeneration, and the dynamics of ROS signaling might help explain differences between wound healing and regeneration. Finally, the heart has been added to those organs that require a nerve supply to regenerate, and a trade-off between regeneration and tumor suppression has been proposed to help explain why mammals regenerate poorly.

Use of the TetON System to Study Molecular Mechanisms of Zebrafish Regeneration

The zebrafish has become a very important model organism for studying vertebrate development, physiology, disease, and tissue regeneration. A thorough understanding of the molecular and cellular mechanisms involved requires experimental tools that allow for inducible, tissue-specific manipulation of gene expression or signaling pathways. Therefore, we and others have recently adapted the TetON system for use in zebrafish. The TetON system facilitates temporally and spatially-controlled gene expression and we have recently used this tool to probe for tissue-specific functions of Wnt/beta-catenin signaling during zebrafish tail fin regeneration. Here we describe the workflow for using the TetON system to achieve inducible, tissue-specific gene expression in the adult regenerating zebrafish tail fin. This includes the generation of stable transgenic TetActivator and TetResponder lines, transgene induction and techniques for verification of tissue-specific gene expression in the fin regenerate. Thus, this protocol serves as blueprint for setting up a functional TetON system in zebrafish and its subsequent use, in particular for studying fin regeneration.

[Post-denervation renal artery stenosis - a matter of concern?]

Renal denervation, an invasive technique indicated in resistant hypertension patients insufficiently controlled by antihypertensive drugs, has a good safety profile. However, an increasing number of post-denervation renal artery stenosis cases has recently been reported. We describe the case of a 49-year-old woman with resistant hypertension who was referred to our university hypertension center for renal sympathetic denervation. Her daily treatment included six antihypertensive drugs. CT angiography prior to denervation showed no renal artery stenosis or vessel wall lesions. A standard renal denervation procedure using the St Jude protocol was performed. After an initial improvement in blood pressure profile, she presented with a blood pressure impairment at 3 months after renal denervation leading to the diagnosis of a severe right renal artery stenosis.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9  h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300  GeV to ∼10  TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24}  cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4  TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

FOXP1 potentiates Wnt/β-catenin signaling in diffuse large B cell lymphoma

The transcription factor FOXP1 (forkhead box protein P1) is a master regulator of stem and progenitor cell biology. In diffuse large B cell lymphoma (DLBCL), copy number amplifications and chromosomal translocations result in overexpression of FOXP1. Increased abundance of FOXP1 in DLBCL is a predictor of poor prognosis and resistance to therapy. We developed a genome-wide, mass spectrometry-coupled, gain-of-function genetic screen, which revealed that FOXP1 potentiates β-catenin-dependent, Wnt-dependent gene expression. Gain- and loss-of-function studies in cell models and zebrafish confirmed that FOXP1 was a general and conserved enhancer of Wnt signaling. In a Wnt-dependent fashion, FOXP1 formed a complex with β-catenin, TCF7L2 (transcription factor 7-like 2), and the acetyltransferase CBP [CREB (adenosine 3',5'-monophosphate response element-binding protein)-binding protein], and this complex bound the promoters of Wnt target genes. FOXP1 promoted the acetylation of β-catenin by CBP, and acetylation was required for FOXP1-mediated potentiation of β-catenin-dependent transcription. In DLBCL, we found that FOXP1 promoted sensitivity to Wnt pathway inhibitors, and knockdown of FOXP1 or blocking β-catenin transcriptional activity slowed xenograft tumor growth. These data connect excessive FOXP1 with β-catenin-dependent signal transduction and provide a molecular rationale for Wnt-directed therapy in DLBCL.

Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.

Search for a dark matter annihilation signal from the galactic center halo with H.E.S.S

A search for a very-high-energy (VHE; ≥100  GeV) γ-ray signal from self-annihilating particle dark matter (DM) is performed towards a region of projected distance r∼45-150  pc from the Galactic center. The background-subtracted γ-ray spectrum measured with the High Energy Stereoscopic System (H.E.S.S.) γ-ray instrument in the energy range between 300 GeV and 30 TeV shows no hint of a residual γ-ray flux. Assuming conventional Navarro-Frenk-White and Einasto density profiles, limits are derived on the velocity-weighted annihilation cross section (σv) as a function of the DM particle mass. These are among the best reported so far for this energy range and in particular differ only little between the chosen density profile parametrizations. In particular, for the DM particle mass of ∼1  TeV, values for (σv) above 3×10(-25)  cm(3) s(-1) are excluded for the Einasto density profile.

Role of pre-infarction angina and inflammatory status in the extent of microvascular obstruction detected by MRI in myocardial infarction patients treated by PCI

BACKGROUND/OBJECTIVES

The extent of microvascular obstruction (MVO) during myocardial infarction referred to as the "no-reflow phenomenon", may determine myocardial damage. Our study aimed to investigate the incidence and the influencing factors of MVO in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous intervention (PCI).

PATIENTS, METHODS

Using contrast-enhanced MRI, microvascular obstruction was defined as early hypoenhancement. Contrast defects were scored from 0 (no hypoenhancement) to 3 (strong hypoenhancement). 50 patients (56+/-11 years) with STEMI underwent PCI. Contrast-enhanced MRI (6+/-2 days after STEMI) and biochemical parameters were evaluated.

RESULTS

Microvascular obstruction (score 1 to 3) was observed in 90% of the patients and major microvascular obstruction (score 2-3) in 54%. In univariate analysis, leukocytes and CRP levels were associated with MVO, whereas pre-infarction angina and prior medication by aspirin or calcium channel antagonist appeared protective. Microvascular obstruction intensity positively correlated with baseline inflammation status assessed by C-reactive protein and leukocytes (rho=0.43 and rho=0.44; p=0.003), the peak of CK (rho=0.56; p=0.01) or Troponin I (rho=0.59; p=0.01) and negatively correlated with LVEF (rho=-0.44; p=0.002). Multivariate analysis identified the absence of pre-infarction angina as the only independent predictor for microvascular obstruction (odds ratio, 8.35, 95% confidence interval 1.27-54.71; p=0.027).

CONCLUSION

MRI-detected microvascular obstruction has a high incidence in patients with STEMI treated by primary PCI and determines post-MI LVEF even in patients with post PCI TIMI 3 flow score. Pre-infarction angina appears to be an independent determinant of the extent of MVO detected by MRI.

[Why screening for a renal artery stenosis?]

Diagnosis of renal artery stenosis (RAS) should be discussed in numerous clinical situations including refractory high blood pressure (HBP), HBP in a polyvascular patient, degradation of renal function following renin angiotensin inhibitor or flash pulmonary edema. Ultrasound-doppler coupled with gadolinium-enhanced MR or CT angiography has proven adequate for most patients with RAS. Digital subtraction angiography should be limited to revascularisation procedures. Functional testing are not sensitive or specific enough because the degree of renin activation differs widely among patients with RAS. Renal percutaneous angioplasty induces a light to moderate decrease in blood pressure, has no effect on renal function but allows to reduce the number of anti-hypertensive drugs. Stenting completed angioplasty is worthwhile in most patients with atherosclerotic RAS. ACE inhibitors decrease mortality and increase renal function in patients with RAS.

Aerosol optical depth, aerosol composition and air pollution during summer and winter conditions in Budapest

The dependence of aerosol optical depth (AOD) on air particulate concentrations in the mixing layer height (MLH) was studied in Budapest in July 2003 and January 2004. During the campaigns gaseous (CO, SO(2), NO(x), O(3)), solid components (PM(2.5), PM(10)), as well as ionic species (ammonium, sulfate and nitrate) were measured at several urban and suburban sites. Additional data were collected from the Budapest air quality monitoring network. AOD was measured by a ground-based sun photometer. The mixing layer height and other common meteorological parameters were recorded. A linear relationship was found between the AOD and the columnar aerosol burden; the best linear fit (R(2)=0.96) was obtained for the secondary sulfate aerosol due to its mostly homogeneous spatial distribution and its optically active size range. The linear relationship is less pronounced for the PM(2.5) and PM(10) fractions since local emissions are very heterogeneous in time and space. The results indicate the importance of the mixing layer height in determining pollutant concentrations. During the winter campaign, when the boundary layer decreases to levels in between the altitudes of the sampling stations, measured concentrations showed significant differences due to different local sources and long-range transport. In the MLH time series unexpected nocturnal peaks were observed. The nocturnal increase of the MLH coincided with decreasing concentrations of all pollutants except for ozone; the ozone concentration increase indicates nocturnal vertical mixing between different air layers.

Jahreszeitliche Schwankungen und Einfluss der Ernährung auf die makuläre Pigmentdichte

PURPOSE

We have previously reported on measuring macular pigment density (MPD) with a scanning laser ophthalmoscope (HRA, Heidelberg Engineering, Heidelberg, Germany). This study war undertaken to evaluate the variation of MPD over a period of 1 year in healthy subjects.

METHOD

We used autofluorescence images recorded with a HRA to evaluate MPD with a 2 degrees circle centered on the fovea. Healthy subjects were included in the study and MPD measurements were repeated every 2 months over a period of 1 year.

RESULTS

We included a total of 30 healthy subjects aged 19-34 years (mean: 23+/-2 years). Mean MPD at time point 1 was 0.215+/-0.056 density units (DU), at time point 2 0.235+/-0.051 DU, at time point 3 0.218+/-0.055 DU, at time point 4 0.228+/-0.057 DU, at time point 5 0.225+/-0.053 DU, and at time point 6 0.203+/-0.050 DU. The statistical analysis revealed no significant variation of MPD over the follow-up period of 1 year.

CONCLUSION

This study demonstrates that MPD shows no variation over a period of 1 year in healthy subjects.

Myocardial flow reserve parametric map, assessed by first-pass MRI compartmental analysis at the chronic stage of infarction

Regional myocardial flow and flow reserve (MFR) were assessed by compartmental analysis of Gd-enhanced MRI first-pass data in 7 patients with atypical chest pain, and in 15 patients with previous transmural myocardial infarction. The FE product (Flow x Extraction coefficient), derived from the modified Kety equation, was measured in regions corresponding to the Tetrofosmine-SPECT fixed defect and in remote normal regions. The FE product at rest and hyperemic FE product were similar in healed revascularized tissues (70.5 +/- 15.6 and 112.5 +/- 19.5 ml/mn/100 g, respectively) and in normal myocardium (76.2 +/- 18.3 and 142.2 +/- 33.0, respectively). In contrast, the FE index (48.8 +/- 15.2 and 60.7 +/- 18.0, respectively, P < 0.01 versus the two previous groups) and the MFR (1.27 +/- 0.20 vs. 1.91 +/- 0.29 in normal regions) were reduced in healed fibrotic tissues when the infarct-related artery remained occluded. Myocardial flow reserve maps allowed correct identification of regions corresponding to an occluded infarct-related artery.

Determination of cutin-bound residues of chlorothalonil by immunoassay

An indirect competitive enzyme-linked immunosorbent assay (ELISA) was used to determine photochemically cutin-bound residues of chlorothalonil in enzymatically isolated tomato and apple fruit cuticles. The samples were spiked, irradiated, exhaustively extracted, and depolymerized with boron trifluoride complex resulting in a soluble depolymerisate. With this procedure, the ELISA could be calibrated with free target molecules for the quantification of originally bound chlorothalonil residues. In fruit cuticles that were irradiated for 8 h by simulated sunlight, 0.030 and 0.068 mg/g photoinduced cutin-bound residues of wax-free cuticles (calculated as chlorothalonil) were determined for tomatoes and apples, respectively. For the used antibody mAb chl. 4/11, cross-reactivities with derivatives of chlorothalonil simulating different types of cuticle-bound residues are given and discussed.

New approaches in the management of choroidal neovascular membrane in age-related macular degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly population. The prevalence is reported to be 1.2-1.4% in several population-based epidemiological studies. Currently 25-30 million people worldwide are blind due to AMD. With the aging world population it is bound to increase significantly, and could become a significant public health problem in next two decades, with serious socio-economic implications. Several strategies are today available to treat the wet form of AMD, which is responsible for significant visual loss. These were until recently confined to laser photocoagulation, and subretinal surgery, but today two other modalities, namely, radiation and photodynamic therapy, are available. These treatment modalities however, are aimed at preservation of vision only, and not at reversing the process of the disease. Further research on antiangiogenic drugs and gene therapy could significantly help AMD patients.

[Cartography of absolute myocardial perfusion with magnetic resonance imaging. Methods and results]

Ultra-rapid dynamic MRI (one image per heart beat) can follow the progression of the intra-myocardial signal during the first passage of diffusable gadolinium chelates injected as a bolus through a peripheral vein. A quantitative evaluation of myocardial perfusion is possible using a compartmental model of analysis. Absolute myocardial flow can be measured at rest and during hyperaemia induced by dipyridamole. It is possible to associate functional mapping, corresponding to parametric images of the flow indices, to the global evaluation. The ratio between the values obtained during hyperaemia and under basal conditions correspond to the myocardial reserve. The principles, results and limitations of this method are discussed in the light of published results, underlining the advantages of absolute flow measurement and of the differences between the results of MRI and myocardial scintigraphy.

Differential expression of linker histone variants in Euplotes crassus

Two genes have been cloned from the ciliate Euplotes crassus that encode proteins with sequence similarity to the linker histones from a variety of organisms. One gene, H1-1, is present on a 1.3-kb macronuclear DNA molecule and encodes a 16.2- kDa protein. The second gene, H1-2, is present on a 0.7-kb DNA molecule and encodes an 18.8-kDa protein. Both H1-1 and H1-2 are expressed in vegetative cells, but the two genes exhibit very different patterns of expression during macronuclear development. H1-1 transcripts accumulate during conjugation and during the final rounds of DNA amplification. H1-2 transcripts accumulate after the onset of polytene chromosome formation and remain high throughout the remainder of macronuclear development. H1-1 is the major perchloric-acid-soluble protein from macronuclei. The pattern of gene expression and the macronuclear location of the H1-1 protein indicate that H1-1 is the predominant linker histone in vegetative macronuclei.

The impact of knee joint flexion on infrainguinal vascular grafts: an angiographic study

OBJECTIVES

To characterise the morphologic behaviour of infrainguinal vascular grafts during flexion of the knee.

DESIGN

A prospective angiographic study.

MATERIALS AND METHODS

In 64 infrainguinal bypass grafts, intravenous digital subtraction angiography was performed within the first postoperative week. Frontal and lateral projection angiograms with the knee joint extended and with a 80-90 degrees flexion were taken. The distal anastomosis of the bypass was performed below-knee in 49 cases (18 in situ veins, 8 reversed veins with an anatomic course, 2 reversed veins with an extra-anatomic course, 4 composite grafts, 15 synthetic grafts with an anatomic course (14 polytetrafluoroethylene (ePTFE), 1 polyurethane), and two synthetic grafts with an extra-anatomic course. Fifteen ePTFE prostheses were implanted in the above-knee position.

RESULTS

Out of 64 cases a total of 16 grafts showed stenotic kinking during flexion: two of the 18 in situ vein grafts, four of the 12 reversed vein grafts implanted with an anatomic course, one of the two reversed vein grafts implanted in an extra-anatomic site, eight of the 15 synthetic grafts crossing the knee, 0 of the two extra-anatomic ePTFE grafts, and one of the 15 cases of above-knee femoropopliteal ePTFE grafts.

CONCLUSIONS

Stenotic kinking due to knee flexion can affect all kinds of bypass grafts including vein grafts placed anatomically and above-knee prostheses.

Decreased sympatho-adrenal activity in diabetic patients with autonomic dysfunction following mental stress

The sympathetic nervous system is of major importance in the regulation of numerous physiological functions. While it is clearly established that there is a decreased noradrenergic status in people with autonomic neuropathy, the epinephrine secretion is much more controversial. Basal and mental stress-stimulated plasma catecholamine levels were measured in 42 diabetic patients with and without pathological cardiovascular function tests and in 13 healthy, non-diabetic control subjects. In addition, the excretion of catecholamines was measured in a 24 h urine collection and compared with the stress stimulated plasma levels. During mental stress exposure a diminished epinephrine secretion was found in diabetic patients with autonomic neuropathy compared with diabetic patients without neuropathy and the healthy control group (p < 0.05: respectively). The decreased epinephrine response to mental stress was strongly correlated with a diminished urinary excretion of this "neurotransmitter' (r = 0.46; p < 0.01). Diabetic patients suffering from cardiovascular autonomic neuropathy exhibit a diminished sympatho-adrenal response following mental stress exposure. Both measurement of urinary and mental stress stimulated plasma epinephrine levels following mental stress provide reliable information regarding sympatho-adrenal activity in diabetic patients.

Assessment of painful ureterohydronephrosis during pregnancy by MR urography

The purpose of this study was to assess the value of the fast imaging sequence called RARE (rapid acquisition with relaxation enhancement) MR urography (or RMU) in pregnant women with painful ureterohydronephrosis. A total of 17 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of US, X-rays and the evolution of symptoms. The gold standard techniques used to evaluate the results of MR urography were US when it showed the entire dilated urinary tract and the nature of the obstruction (9 cases), limited intravenous urography (IVU) when performed (3 cases) or endoscopic procedure (5 cases). The accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (sensitivity 100% in our series). The determination of the type of obstruction, intrinsic vs extrinsic, was always exact. The RMU technique alone could not specify the exact nature of the obstruction. The RMU technique is able to differentiate a physiological from a pathological ureterohydronephrosis during pregnancy. It could be considered as the procedure of choice when US failed to establish the differential diagnosis.

[Endovascular treatment of hemorrhagic renal angiomyolipoma with platinum microcoils]

Haemorrhage is the major complication of renal angiomyolipoma and is classically treated surgically, but embolization constitutes an alternative treatment. Improvement of catheters and embolization materials now allows highly selective embolization. The authors present a case in which the use of a variable stiffness catheter and platinum microcoils allowed highly selective embolization of a haemorrhagic renal angiomyolipoma while preserving the functional renal parenchyma.

Fast imaging MR assessment of ureterohydronephrosis during pregnancy

PURPOSE

to assess the value of the fast imaging sequence called RARE-MR-Urography (RMU) for the diagnosis of pathologic ureterohydronephrosis during pregnancy.

MATERIALS AND METHODS

15 pregnant women with an acute flank pain were examined with RMU. Results were compared with those of ultrasonography (US), X-rays, and the evolution of symptoms.

RESULTS

the accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic vs. extrinsic, was always exact. RMU alone cannot specify the exact nature of the intrinsic obstruction. Ultrasonography gave less sensitive information in terms of level (60%) and type of obstruction (53%).

CONCLUSION

RMU is able to differentiate a physiological from a pathologic ureterohydronephrosis during pregnancy. It could be considered as a procedure of choice for special cases when US failed to establish this differential diagnosis.

Evaluation of RARE-MR urography in the assessment of ureterohydronephrosis

OBJECTIVE

The goal of this prospective study was to evaluate the value of the fast imaging sequence called RARE-MR urography (RMU) for the diagnosis of ureterohydronephrosis.

MATERIALS AND METHODS

Sixty-nine patients underwent this procedure. The results were compared with those obtained by intravenous urography (IVU) and ultrasonography (US).

RESULTS

The accuracy of RMU in the detection of urinary tract dilatation and the localization of the level of obstruction was excellent (100%). The determination of the type of obstruction, intrinsic versus extrinsic, was 80% by IVU and 60% for RMU. The RMU sequence alone could not specify the nature of the obstruction. Functional information about the obstructed collecting system could not be obtained.

CONCLUSION

The RMU technique may be considered in the following circumstances: contraindications to IVU (allergy to contrast medium, severe renal failure), impairment of renal excretion, and failure to locate the level of obstruction by US. The absence of ionizing radiations favors the promotion of this procedure to study ureterohydronephrosis during pregnancy.

[Captopril test for detecting renal artery stenosis: changes in plasma renin concentration]

The aim of this study was to demonstrate the diagnostic value of changes in active renin concentration during the captopril test (measurements of plasmatic active renin concentrations, before 12.5 or 37.5 mg of captopril p.o., and 30 and 90 minutes after) in order to screen a significant renal artery stenosis. After a renal angiography, 88 hypertensive patients suspected of renovascular hypertension were classified according to the percentage of stenosis in the main renal artery: class I (< 30% - n = 50), II (30 to < 75% - n = 21), III (75 to < 90% - n = 8) and IV (90 to 100% - n = 11). The results of the captopril test were compared to those of renal angiography. The active renin before the test (basal AR), the greater increase in active renin after captopril (max AR), the difference between max AR and basal AR (DIF) and the active renin relative change after the test (RC) were compared in the 4 classes (ANOVA). There were no differences in diastolic blood pressure (> or = 90 mmHg) natriuresis (100 mmol/24 h in mean) between these different classes. The basal AR, the max AR, the DIF and the RC significantly differed between the 4 classes. They were greater in class III and IV than in class I. The positive criteria for the captopril test were max AR, DIF and RC. The positivity thresholds were max AR > or = 70 ng/l, DIF > or = 50 ng/l and RC > or = 165% (upper limit in the class I 95% confidence interval for each criterion).(ABSTRACT TRUNCATED AT 250 WORDS)

[Contribution of imaging to the study of aortic aneurysms]

All aortic aneurysms require a positive diagnosis, a differential diagnosis and an assessment of extension. Several exploratory methods can be contemplated. In patients with warning symptoms, conventional radiology may point to the diagnosis. The reference method remains retrograde aortography which may be either conventional and seriographic or, better, radiocinematic with orthogonal projections and, if possible, digital. The site and morphology of the aneurysm, and in particular its inner channel are thus demonstrated. Computerized tomography is less invasive and usually of great value, notably for the horizontal, thoracic and abdominal aorta, not only to confirm the diagnosis but also to determine the size of the inner channel, parietal thrombi and aortic walls, as well as relations with nearby structures. Other, totally non-invasive methods are widely utilized to explore aortic aneurysms. These are ultrasonography and its variants (notably Doppler-echocardiography and the transoesophageal route), and magnetic resonance imaging which provides three-dimensional and anatomical views of the vessel. These last two examinations alone usually confirm and outline the aortic aneurysms. They must therefore be utilized as first-line examination, arteriography it is various forms being reserved for emergencies or special cases.

Serum-erythropoietin concentration during acute cardiogenic pulmonary edema

Reduced oxygen tension is regarded as the primary physiologic signal for the production of erythropoietin (EPO). There is little information available about early changes of EPO production in man due to severe hypoxia. The purpose of the present study was to examine the time course of EPO in serum of patients with acute cardiogenic pulmonary edema (ACPE). In 29 patients (seventy-five +/- six years, mean age +/- SEM) who were hospitalized within two hours after onset of symptoms of ACPE, serum EPO concentrations were monitored for up to seventy-two hours. At the moment of admission all patients showed significantly increased EPO concentrations of 121 +/- 64 mU/mL (mean +/- SEM) compared with a healthy population (15-35 mU/mL). Twenty-three patients who recovered within thirty minutes (group A) exhibited a quick return of their EPO serum levels to normal. The remaining 6 patients (group B) had a protracted clinical course and their EPO concentration showed a further increase up to the end of the observation period. The comparative monitoring of concentrations of alpha-1-proteinase inhibitor, antithrombin III, C-reactive protein, fibronectin, hapotoglobin, and transerrin in serum and plasma revealed no significant changes. Thus a major contribution of fluid shifts into or from the intravascular compartment to the observed changes in EPO concentration seems to be unlikely. The data suggest that the production and release of EPO in the kidneys due to altered oxygen delivery is a fast-responding mechanism.

Pharmacokinetics and dose response after intravenous and subcutaneous administration of recombinant erythropoietin in patients on regular haemodialysis treatment or continuous ambulatory peritoneal dialysis

The pharmacokinetics and dose response of recombinant human erythropoietin (rhEPO), administered intravenously and subcutaneously, were studied in chronic haemodialysis (HD) patients and in patients on chronic ambulatory peritoneal dialysis (CAPD). Furthermore, two products differing in the presence of albumin as preservative were compared. Although the pharmacokinetics differed after intravenous and subcutaneous administration, the dose response was the same. There is no statistically significant difference in the pharmacokinetics between the rhEPO in HD and CAPD, nor had the presence of albumin as preservative an influence on the pharmacokinetics.