[Hyperviscosity syndrome]. / Syndrome d'hyperviscosité plasmatique.

Hyperviscosity syndrome is a life-threatening complication. Clinical manifestations include neurological impairment, visual disturbance and bleeding. Measurement of plasma or serum viscosity by a viscometer assesses the diagnosis. Funduscopic examination is a key exam because abnormalities are well-correlated with abnormal plasma viscosity. Etiologies are various but symptomatic hyperviscosity is more common in Waldenström's macroglobulinemia and multiple myeloma. Prompt treatment is needed: treatment of the underlying disease should be considered, but generally not sufficient. Symptomatic measures aim to not exacerbate blood viscosity while urgent plasmapheresis effectively reduces the paraprotein concentration and relieves symptoms.

Life-threatening complications and outcomes in patients with malignancies and severe pulmonary embolism.

BACKGROUND: Data are scarce about ICU patients with malignancy and severe pulmonary embolism. Here, our main objective was to identify risk factors for life-threatening complications, organ failures, and death in ICU patients with severe pulmonary embolism, with special attention to the impact of malignancy. We also described the clinical features of PE in patients with and without malignancies. METHODS: Data from consecutive adults admitted to our ICU in 2002-2011 with severe pulmonary embolism were collected retrospectively. Multivariate analysis was performed to look for factors associated with death, organ failures, or life-threatening complications (major bleeding, recurrent PE, and cardiac arrest). RESULTS: Of 119 included patients (42 [35%] with bilateral pulmonary embolism), 41 had solid malignancies, 27 hematological malignancies, and 51 no malignancies. The most common symptoms were syncope (40%) and hemoptysis (18%) in patients with solid and hematological malignancies, respectively. Life-threatening complications occurred in 23 (19%) patients; risk factors were obesity (OR, 13.22; 1.93-90.70), disseminated intravascular coagulation/ischemic hepatitis (OR, 27.06; 5.14-142.46), fluid load ≥1000 mL/24 h (OR, 6.42; 1.60-25.76), and solid malignancy (OR, 5.45; 1.15-25.89). Inhospital mortality was 27/119 (23%) and respiratory or circulatory failure developed in 36 (30%) patients. Risk factors for these adverse outcomes were older age (OR, 1.04/year; 1.01-1.07), higher oxygen flow rate (OR, 1.28/L; 1.13-1.45); and renal failure (OR, 8.08; 2.50-26.11); whereas chest pain was protective (OR, 0.13; 0.04-0.48). CONCLUSION: In this study, solid malignancy was a risk factor for life-threatening complications but not for death.

Diagnostic contribution from pulmonary biopsies in hematology patients with acute respiratory failure from undetermined etiology.

BACKGROUND: In about 20% of patients with malignancies with acute respiratory failure (ARF), no etiology can be determined, whatever the diagnostic strategy used. Lung biopsy could then be a precious diagnostic tool leading to therapeutic adaptations and increasing chances for cure. The aim of this study was to assess the diagnostic contribution of lung biopsy in patients for whom a complete diagnosis strategy failed to identify ARF etiology. METHODS: All hematology patients admitted for ARF to our ICU between 1995 and 2011, and for whom lung biopsy was performed were included in the study. Lung biopsies were surgical, CT guided, or post-mortem. Histological findings were compared to prebiopsy diagnosis and classified into specific or non-specific diagnosis. Therapeutic impact (or Goldman-class in post-mortem biopsies) was also recorded. RESULTS: Among the 1440 hematology patients with ARF managed during the study period, 21 (1%) biopsies were performed, including 10 post-mortem biopsies. Histological diagnoses were specific in 10 biopsies, non specific in 8 biopsies and lung parenchyma was normal in three patients. In 8/11 (72.7%) alive patients, lung biopsy had lead to therapeutic modifications, including treatment implementation in 5 patients and treatment withdrawal in 3 patients. One out of 10 (10%) patients had minor complications. For the 10 dead patients, only one Goldman-type 1 error was found. CONCLUSION: Diagnostic lung biopsy is rarely needed in hematology patients with ARF. But, it has a 73% therapeutic impact and has overall no major complications. Contribution from post-mortem biopsies seems less relevant.

Kidney biopsy in the critically ill patient, results of a multicentre retrospective case series.

BACKGROUND: The impact of a contributive result of kidney biopsy on the management of patients in the intensive care unit (ICU) has not been extensively investigated yet. METHODS: This was a retrospective study conducted between 2000 and 2011 in five French ICUs. The study included 56 patients. They had at least one non-renal organ failure, as defined by a Sequential Organ Failure Assessment (SOFA) score ≥3 on ICU admission, and kidney biopsy was performed during ICU stay. Kidney samples were obtained by percutaneous (N.=55) or transjugular biopsy (N.=1). RESULTS: The mean Simplified Acute Physiology Score II and total SOFA scores on ICU admission were 52±19 years and 10.3±3.6, respectively. ICU mortality was 23%. The median (interquartile range) time between ICU admission and kidney biopsy was 9 days (5-21). Pathologic findings in the 54 analyzable kidney biopsies were acute tubular necrosis (N.=26), glomerulonephritis (N.=14), acute vascular nephritis (N.=11), acute interstitial nephritis (N.=6), and deposit disease (N.=3). Kidney biopsy was contributive to the management of 40 patients. In 23 of these, new treatments were started, in 13 ongoing treatments were stopped, including four life-sustaining therapies, and in 13 it was decided to start chronic renal replacement. Severe bleeding was observed in 7 patients, with fatal outcome in one case. CONCLUSION: Kidney biopsy may have a significant impact on the management of critically ill patients. Further studies should be done to identify the groups of ICU patients likely to benefit from the procedure with minimum risk.

Dexamethasone in patients with acute lung injury from acute monocytic leukaemia.

The use of steroids is not required in myeloid malignancies and remains controversial in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). We sought to evaluate dexamethasone in patients with ALI/ARDS caused by acute monocytic leukaemia (AML FAB-M5) via either leukostasis or leukaemic infiltration. Dexamethasone (10 mg every 6 h until neutropenia) was added to chemotherapy and intensive care unit (ICU) management in 20 consecutive patients between 2005 and 2008, whose data were compared with those from 20 historical controls (1994-2002). ICU mortality was the primary criterion. We also compared respiratory deterioration rates, need for ventilation and nosocomial infections. 17 (85%) patients had hyperleukocytosis, 19 (95%) had leukaemic masses, and all 20 had severe pancytopenia. All patients presented with respiratory symptoms and pulmonary infiltrates prior to AML FAB-M5 diagnosis. Compared with historical controls, dexamethasone-treated patients had a significantly lower ICU mortality rate (20% versus 50%; p = 0.04) and a trend for less respiratory deterioration (50% versus 80%; p = 0.07). There were no significant increases in the rates of infections with dexamethasone. In conclusion, in patients with ALI/ARDS related to AML FAB-M5, adding dexamethasone to conventional chemotherapy seemed effective and safe. These results warrant a controlled trial of dexamethasone versus placebo in AML FAB-M5 patients with noninfectious pulmonary infiltrates.

Slaughterhouse blood as a perfusate for studying myocardial function under ischemic conditions

Metabolic studies using the in vitro non-recirculating blood-perfused isolated heart model require large volumes of blood. The present study was designed to determine whether heterologous pig blood collected from a slaughterhouse can be used as perfusate for isolated pig hearts perfused under aerobic and constant reduced flow conditions. Eight isolated working pig hearts perfused for 90 min at a constant flow of 1.5 ml g-1 min-1 with non-recirculated blood diluted with Krebs-Henseleit bicarbonate buffer at a hematocrit of 23 percent were compared to eight hearts subjected to the same protocol but perfused only with Krebs-Henseleit bicarbonate buffer solution. Hearts were paced at 100 bpm and subjected to aerobic perfusion at 38ºC. Hearts were weighed before perfusion and at the end of the experiment and the results are reported as percent weight gain (mean ± SD). Comparisons between groups were performed by the Student t-test (P<0.05). After 90 min of perfusion with modified Krebs-Henseleit, perfused hearts presented a larger weight gain than blood-perfused hearts (39.34 ± 9.27 vs 23.13 ± 5.42 percent, P = 0.003). Left ventricular end-diastolic pressure was higher in the modified Krebs-Henseleit-perfused group than in the blood group (2.8 ± 0.4 vs 2.3 ± 0.3 mmHg, respectively, P = 0.01). We conclude that heterologous blood perfusion, by preserving a more physiological myocardial water content, is a better perfusion fluid than modified Krebs-Henseleit solution for quantitative studies of myocardial metabolism and heart function under ischemic conditions

SLC-1 receptor mediates effect of melanin-concentrating hormone on feeding behavior in rat: a structure-activity study.

Several studies have shown that melanin-concentrating hormone (MCH) is an orexigenic peptide in rat. In the present study, a structure-activity relationship with MCH analogs was performed in rat, both in vitro and in vivo. On rat recombinant SLC-1 receptor, both cAMP inhibition and [(125)I]S36057 binding were measured. In vivo, these analogs were injected intracerebroventricularly in rats and their effects were evaluated upon food intake. First, data obtained with the rat recombinant receptor were highly correlated with those obtained from its human counterpart. Second, agonist potencies in the cAMP assay were also highly correlated with binding affinities. These peptides could be classified into several groups according to their potency at the SLC-1 receptor (from subnanomolar activity to complete inactivity). Indeed, there was a strong correlation between their effects upon food intake and the results obtained at the rat SLC-1 receptor. The present report describes for the first time the rat SLC-1 receptor pharmacology and clearly establishes the relevance of the SLC-1 receptor in feeding behavior.

Binding of prostaglandins to human PPARgamma: tool assessment and new natural ligands.

The peroxisome proliferator-activated receptors (PPAR) form a family of nuclear receptors with a wide variety of biological roles from adipogenesis to carcinogenesis. More ligands (agonist and antagonist) are needed to explore the multiple functions of PPAR, particularly PPARgamma. In order to complete such ligand screening, a binding test should be assessed versus the classical transactivation reporter gene assay. In the present work, the full-length human PPARgamma protein as well as its ligand binding domain portion were expressed in Escherichia coli. Bacterial membrane preparations expressing those constructs were characterized using a classical binding competition assay [3H]rosiglitazone as the radioligand. When the receptor preparations were soluble, binding had to be measured with a new alternative method. The systems were assessed using a series of reference PPAR (alpha, beta and gamma) ligands. The full-length human PPARgamma fused to glutathione-S-transferase, expressed in E. coli and tested as a bacterial membrane-bound protein led to the most accurate results when compared to the literature. Furthermore, in an attempt to complete the panel of natural PPARgamma ligands, 29 commercially available prostaglandins were screened in the binding assay. Prostaglandins H(1) and H(2) were found to be modest ligands, however as potent as 15Delta(12-14 )prostaglandin J(2). These results were confirmed in the classical transactivation assay. The fact that these three prostaglandins were equally potent, suggests new pathways of PPARgamma-linked gene activation.

Structure-activity relationship studies of melanin-concentrating hormone (MCH)-related peptide ligands at SLC-1, the human MCH receptor.

Melanin-concentrating hormone (MCH) is a cyclic nonadecapeptide involved in the regulation of feeding behavior, which acts through a G protein-coupled receptor (SLC-1) inhibiting adenylcyclase activity. In this study, 57 analogues of MCH were investigated on the recently cloned human MCH receptor stably expressed in HEK293 cells, on both the inhibition of forskolin-stimulated cAMP production and guanosine-5'-O-(3-[(35)S]thiotriphosphate ([(35)S]- GTPgammaS) binding. The dodecapeptide MCH-(6-17) (MCH ring between Cys(7) and Cys(16), with a single extra amino acid at the N terminus (Arg(6)) and at the C terminus (Trp(17))) was found to be the minimal sequence required for a full and potent agonistic response on cAMP formation and [(35)S]- GTPgammaS binding. We Ala-scanned this dodecapeptide and found that only 3 of 8 amino acids of the ring, namely Met(8), Arg(11), and Tyr(13), were essential to elicit full and potent responses in both tests. Deletions inside the ring led either to inactivity or to poor antagonists with potencies in the micromolar range. Cys(7) and Cys(16) were substituted by Asp and Lys or one of their analogues, in an attempt to replace the disulfide bridge by an amide bond. However, those modifications were deleterious for agonistic activity. In [(35)S]- GTPgammaS binding, these compounds behaved as weak antagonists (K(B) 1-4 microm). Finally, substitution in MCH-(6-17) of 6 out of 12 amino acids by non-natural residues and concomitant replacement of the disulfide bond by an amide bond led to three compounds with potent antagonistic properties (K(B) = 0.1-0.2 microm). Exploitation of these structure-activity relationships should open the way to the design of short and stable MCH peptide antagonists.

Endothelin-1 pathway in human alveolar epithelial cell line A549 and human umbilical vein endothelial cells.

AIM: This study was designed to characterize the endothelin pathway in an immortalized human adenocarcinoma-derived alveolar epithelial cell line (A549) and human umbilical vein endothelial cell line (HUVEC). METHODS: The release of ET-1 and big-ET-1 was measured in the incubation medium of both cell lines. The expression of mRNAs coding for the endothelin isoforms (hppET-1, -2, -3), the endothelin converting enzymes (hECE-1a, b, c, and d) and the hETA and hETB receptors was investigated using RT-PCR. The expression of ECE-1 mRNA in various human tissues and in A549 cells was investigated by Northern blot analysis and the subcellular localization of ECE-1 in A549 cells was investigated by immunoblotting using a polyclonal antibody. RESULTS: Under control conditions, HUVEC release both ET-1 and big-ET-1 (ratio 5 to 1) while in A549 cells the big-ET-1 levels were below the threshold of detection. The release of these two peptides was minimally affected by various inhibitors of peptidases. However, in both cell lines phosphoramidon produced a concentration-dependent inhibition of ET-1 release and an enhanced accumulation of big-ET-1. Both HUVEC and A549 cells express the mRNAs for ppET-1, ET-A, and ET-B receptor subtypes and ECE-1 (isoforms ECE-1b, c and/or d). In addition, in HUVEC the mRNAs for ppET-2 and for the isoform ECE-1a were also detected. In A549 cells, ECE-1 had a preferential subcellular localization in the membrane fraction but was not detected in the cytosol. CONCLUSION: Both A549 and HUVEC produce and release endothelin-1 through a specific enzymatic pathway, whether or not ECE-1 is the only enzyme involved remains to be determined. A549 might be used as a screening assay for drug discovery such as for inhibitors of endothelin-1 release.

Predictive value of regional left ventricular circumferential shortening in jeopardized myocardium. A two-dimensional SPAMM cine-MRI study in a canine model.

OBJECTIVE: To determine whether myocardial circumferential shortening assessed in the different myocardial layers by SPAMM cine-MRI may help to discriminate between various degrees of myocardial injury in reperfused myocardium. METHODS: Dogs underwent 90 minutes of coronary occlusion and 24 hours of reperfusion. Using a 1.5 T whole-body MR scanner, SPAMM cine-MRI images were acquired before and 24 hours after surgery on the short axis plan of the left ventricle and analyzed to evaluate the mean myocardial circumferential shortening (% MCS) in the different layers. Based on the residual blood flow, animals were assigned to group I (residual flow < 22.5%) or group II (residual flow > 22.5%). RESULTS: Dogs in group I developed larger infarctions (25.3% +/- 14.6 of the area at risk, n = 5) compared with those in group II (5.81% +/- 1.1, n = 7, P < 0.05). In the jeopardized zone, the % MCS of the subendocardium decreased more significantly in group I (-0.03% +/- 3.7 to 2.2% +/- 5.2) compared with group II (14.7% +/- 1.5 to 18.4% +/- 1.4). CONCLUSIONS: SPAMM cine-MRI is a fast and noninvasive means of measuring % MCS. The MR measurement of this parameter in the subendocardial layer appears quite accurate in describing the degree of damage in reperfused myocardium.

Investigation of S-farnesyl transferase substrate specificity with combinatorial tetrapeptide libraries.

Using biased tetrapeptide libraries made up of proteinogenic amino acids of the general formula Cys-O2-X3-X4, we searched for new substrates of partly purified rat brain S-farnesyl transferase (FTase). To achieve this task, an assay was developed in which the consumption of the co-substrate (farnesyl pyrophosphate) was measured. After three steps of deconvolution including each synthesis and enzymatic assay, the most efficient substrates found under these particular conditions were Cys-Lys-Gln-Gln (peptide I) and Cys-Lys-Gln-Met (peptide II). As a control, we used another tetrapeptide library (Cys-Val-O3-X4) in which the valine position was arbitrarily fixed, corresponding to Cys-Val-Ile-Met in the CAAX box of K-RasB, although this sublibrary was only marginally active compared with Cys-Lys-X3-X4 in the first round of deconvolution. The best substrate sublibrary was Cys-Val-Thr-X4, threonine being more favourable than the aliphatic amino acids (Val, Ile, Leu, Ala) in this position. Deconvolution finally led to Cys-Val-Thr-Gln, -Met, -Thr and -Ser as the most efficient substrates of FTase. Those tetrapeptides were not substrates of a partly purified geranylgeranyl transferase 1 (GGTase1). We also investigated the influence of the -1 position (at the N-terminus of cysteine) on the specificity of the enzyme, by using a series of pentapeptides constructed on the basis of the best tetrapeptide core (peptide 1). Among this family of analogues, only His-Cys-Lys-Gln-Gln did not behave as a substrate, whereas all the other pentapeptides were measurable substrates, with Gly-, Asn- and Thr-Cys-Lys-Gln-Gln displaying kinetic constants similar to that of Cys-Lys-Gln-Gln. The present work provides strong evidence that the best tetrapeptide substrates of FTase do not necessarily belong to the classical CAAX box, in which A's are lipophilic residues, but rather contain hydrophilic amino acids in the middle of their sequences. Among them, peptides I and II are potent FTase in vitro substrates that are not recognised by GGTase1 and might be new starting points for the design of FTase inhibitors.

Ultrasmall superparamagnetic iron oxide particles (AMI 227) as a blood pool contrast agent for MR angiography: experimental study in rabbits.

The purpose of this study was to evaluate the contribution of an ultrasmall superparamagnetic iron oxide particles (USPIOs) based contrast agent (AMI 227), in a transverse three-dimensional time-of-flight TONE MR angiography sequence of abdominal aorta in rabbits. The main goal was to assess improvement in the visualization of small arteries such as renal arteries, when using such a sequence. Imaging experiments were performed on a 1.5 T magnet, using a transverse 3D time-of-flight (TOF) tilted optimized nonsaturating excitation (TONE) sequence with magnetization transfer suppression. The contrast media used were composed of a USPIO core surrounded by a dextran-surfactant (AMI 227). Different concentrations of AMI 227 were evaluated in 12 rabbits. Concentrations varied within the range 8.5-34 micromol Fe/kg - bw: 8.5 micromol Fe/kg (three rabbits); 17 micromol Fe/kg (three rabbits); 25.5 micromol Fe/kg (three rabbits); 34 micromol Fe/kg (three rabbits). A visual analysis based on the improvement of visualization of small arteries (renal arteries) on MIP images and a quantitative analysis based on the percentage of contrast enhancement of the aorta plotted against distance in the slab from the top edge of the acquisition volume were obtained. A signal-to-noise ratio enhancement of the distal part of the aorta and only improvement in the delineation of the renal arteries were noted when using low concentrations of the contrast media. A loss of signal-to-noise ratio of the aorta and a decrease in arterial visualization were respectively noted with higher concentration of contrast media. In this experimental study, using a transverse three-dimensional TOF TONE MR angiography sequence of renal arteries, in which sequence the saturation effect is minimized, the use of AMI 227 allows only improvement in the delineation of small arteries when using low concentrations of contrast media.

An almitrine analog acts as hypoxia in isolated rat lungs.

The present study was designed to point out similarities between the effects on pulmonary circulation caused by hypoxia and by a chemoreceptor stimulant (S1867, an almitrine analog). Isolated rat lungs were perfused at a constant flow with homologous blood and ventilated under normoxic, hypoxic or hyperoxic conditions. (1) At 0.25 microgram/ml, S1867 potentiated the hypoxic pressor response, while at 1 microgram/ml, it induced a significant increase in pulmonary artery pressure (PAP) at 21% O2. (2) Since the expression of an oxygen-binding protein (NADPH-oxidase like) has been demonstrated in the rat carotid bodies, we studied the effects of the NADPH-oxidase inhibitor diphenyleneiodonium (DPI) on HPV and on S1867-induced pulmonary vascular responses. Both responses were totally abolished by DPI (40 microM), whereas the vasoconstriction induced by a thromboxane A2 analog (U46619) remained unchanged. (3) Vascular responses to hypoxia and S1867 (1 microgram/ml) were both reversed by a bolus of the sulfhydryl oxidant diamide (3 mg). (4) The S1867-induced response was prevented and reversed by the supply of inhaled oxygen, which was without action on the vasoconstriction induced by U46619. These results suggest that the almitrine analog and hypoxia act at least partly through the same cellular mechanism, involving a DPI-sensitive protein.

In vitro down-regulation of antigen-induced IL-5 gene expression and protein production by cAMP-specific phosphodiesterase type 4 inhibitor.

The effects of cAMP-elevating agents on antigen-induced IL-5 (interleukin-5) messenger RNA expression and protein production were examined in vitro in an antigen-driven system of splenocytes from ovalbumin sensitized BALB/c mice. IL-5 production was inhibited by rolipram, a type 4 phosphodiesterase (PDE4) inhibitor, dose-dependently (maximally at 10(-5) M) and by dibutyryl-cAMP (db-cAMP) (3 x 10(-4) M), but not by the type 3 and type 5 PDE inhibitors milrinone and zaprinast (10(-5) M), respectively. Forskolin (10(-5) M), an adenylate cyclase activator, was noninhibitory alone but potentiated inhibition by rolipram. Inhibition was associated with a decrease in IL-5 mRNA expression. Cycloheximide 10(-6) M and actinomycin 2 micrograms/ml abolished IL-5 production and mRNA expression. We conclude that in splenocytes from sensitized mice, IL-5 production and mRNA expression depend on antigen stimulation. The time course of IL-5 protein production is closely related to IL-5 mRNA expression and depends on de novo protein synthesis. db-cAMP and a selective PDE4 inhibitor, alone or in combination with forskolin, are the only cAMP-elevating agents that dose-dependently inhibited antigen-induced IL-5 mRNA expression and protein production. These results are in agreement with in vivo inhibition by a selective PDE4 inhibitor of antigen-induced pulmonary eosinophil infiltration and IL-5 production in sensitized mice, and they suggest that PDE4 inhibitors have potential for treating respiratory allergy.

Superparamagnetic iron oxide particles and positive enhancement for myocardial perfusion studies assessed by subsecond T1-weighted MRI.

Superparamagnetic iron oxide particles (SPIOs) are usually referred to as T2 MR contrast agents, reducing signal intensity (SI) on T2-weighted MR images (negative enhancement). This study reports the original use of SPIOs as T1-enhancing contrast agents, primarily assessed in vitro, and then applied to an in vivo investigation of a myocardial perfusion defect. Using a strongly T1-weighted subsecond MR sequence with SPIOs intravenous (IV) bolus injection, MR imaging of myocardial vascularization after reperfusion was performed, on a dog model of coronary occlusion followed by reperfusion. Immediately after the intravenous bolus injection of 20 mumol/kg of SPIOs, a positive signal intensity enhancement was observed respectively, in the right and left ventricular cavity and in the nonischemic left myocardium. Moreover, compared to normal myocardium, the remaining ischemic myocardial region (anterior wall of the left ventricle) appeared as a lower and delayed SI enhancing area (cold spot). Mean peak SIE in the nonischemic myocardium (posterior wall) was significantly higher than in the ischemic myocardium (anterior wall) (110 +/- 23% vs. 74 +/- 22%, Mann-Whitney test alpha < 1%, n1 = 6, n2-n1 = 0, U > 2). In conclusion, the T1 effect of SPIOs at low dose, during their first intravascular distribution, suggests their potential use as positive markers to investigate the regional myocardial blood flow and some perfusion defects such as the "no-reflow phenomenon."

[Duct cysts of the parotid. Complications of dilated Stensen's duct]. / Kystes canalaires de la parotide. Complication des mégasténons.

The classification of parotid cysts is still uncertain and confusing, especially regarding true glandular cysts. In contrast, the pathogenesis of parotid duct cysts has generally been demonstrated by recognition of constitutional dysplastic dilatation and complicating stenotic phenomena.