Successful use of levosimendan in a patient with cardiogenic shock complicating acute myocardial infarction

Levosimendan is a new inodilator that improves cardiac contractility by sensitizing troponin C to calcium. This drug has proved to be effective in treating advanced congestive heart failure but has not been evaluated in cardiogenic shock. We present the case of a 54-year-old male patient treated successfully with levosimendan for cardiogenic shock following acute myocardial infarction. Treatment with dobulamine. revascularisation and itra-aortic balloon conterpulsation had first failed to improve his hemodynamic variables. Levosimendan induced a steady decline of increased pulmonary capillary wedge pressure, followed by an increase in cardiac index and mixed venous oxygen saturation. Left ventricular ejection fraction improved from 25% to 47%. Infusion of levosimendan can be used in cardiogenic shock without side effects and to improve hemodynamics and left ventricular function.     

Comparison of MRI and CT for detection of acute intracerebral hemorrhage

Context  Noncontrast computed tomography (CT) is the standard brain imaging study for the initial evaluation of patients with acute stroke symptoms. Multimodal magnetic resonance imaging (MRI) has been proposed as an alternative to CT in the emergency stroke setting. However, the accuracy of MRI relative to CT for the detection of hyperacute intracerebral hemorrhage has not been demonstrated. Objective  To compare the accuracy of MRI and CT for detection of acute intracerebral hemorrhage in patients presenting with acute focal stroke symptoms. Design, Setting, and Patients  A prospective, multicenter study was performed at 2 stroke centers (UCLA Medical Center and Suburban Hospital, Bethesda, Md), between October 2000 and February 2003. Patients presenting with focal stroke symptoms within 6 hours of onset underwent brain MRI followed by noncontrast CT. Main Outcome Measures  Acute intracerebral hemorrhage and any intracerebral hemorrhage diagnosed on gradient recalled echo (GRE) MRI and CT scans by a consensus of 4 blinded readers. Results  The study was stopped early, after 200 patients were enrolled, when it became apparent at the time of an unplanned interim analysis that MRI was detecting cases of hemorrhagic transformation not detected by CT. For the diagnosis of any hemorrhage, MRI was positive in 71 patients with CT positive in 29 (P<.001). For the diagnosis of acute hemorrhage, MRI and CT were equivalent (96% concordance). Acute hemorrhage was diagnosed in 25 patients on both MRI and CT. In 4 other patients, acute hemorrhage was present on MRI but not on the corresponding CT—each of these 4 cases was interpreted as hemorrhagic transformation of an ischemic infarct. In 3 patients, regions interpreted as acute hemorrhage on CT were interpreted as chronic hemorrhage on MRI. In 1 patient, subarachnoid hemorrhage was diagnosed on CT but not on MRI. In 49 patients, chronic hemorrhage, most often microbleeds, was visualized on MRI but not on CT. Conclusion  MRI may be as accurate as CT for the detection of acute hemorrhage in patients presenting with acute focal stroke symptoms and is more accurate than CT for the detection of chronic intracerebral hemorrhage.      

Cdc25C phosphorylation on serine 191 by Plk3 promotes its nuclear translocation

Mitosis in human cells is initiated at the end of G2 by activation of the Cdc2/cyclin B complex. Activation occurs by dephosphorylation of the inhibitory residues, threonine 14 (T14) and tyrosine 15 (Y15), on Cdc2 by the Cdc25C phosphatase. Entry into mitosis is regulated by the subcellular relocalization of Cdc2/cyclin B, which is rapidly imported into the nucleus at the end of G2. Here, we show that polo-like kinase 3 (Plk3) is able to phosphorylate Cdc25C primarily on S191, and to a lesser extent on S198 in vitro, both of which are within a nuclear exclusion motif. Following transfection, the S191D Cdc25C mutant leads to an enhanced accumulation of Cdc25C in the nucleus, while the S191A mutant facilitated the Cdc25C nuclear exclusion. Furthermore, translocation of Cdc25C to the nucleus was accompanied by a decrease in Cdc2 phosphorylation on Y15. Plk3-WT overexpression led to a sharp increase in Cdc25C nuclear accumulation, while Plk3-KD overexpression failed to do so. The effect of Plk3 overexpression on Cdc25C was reversed by coexpression of a Plk3 siRNA. These results support a role for the polo kinases in coordinating the translocation and perhaps the timing of both Cdc25C and its target Cdc2/cyclin B to the nucleus upon entry into mitosis.     

Sustained polymeric delivery of gene silencing antisense ODNs, siRNA, DNAzymes and ribozymes: in vitro and in vivo studies

Small interfering RNA (siRNA), antisense oligonucleotides (ODNs), ribozymes and DNAzymes have emerged as sequence-specific inhibitors of gene expression that may have therapeutic potential in the treatment of a wide range of diseases. Due to their rapid degradation in vivo, the efficacy of naked gene silencing nucleic acids is relatively short lived. The entrapment of these nucleic acids within biodegradable sustained-release delivery systems may improve their stability and reduce the doses required for efficacy. In this study, we have evaluated the potential in vitro and in vivo use of biodegradable poly (D,L-lactide-co-glycolide) copolymer (PLGA) microspheres as sustained delivery devices for ODNs, ribozyme, siRNA and DNA enzymes. In addition, we investigated the release of ODN conjugates bearing 5'-end lipophilic groups. The in vitro sustained release profiles of microsphere-entrapped nucleic acids were dependent on variables such as the type of nucleic acid used, the nature of the lipophilic group, and whether the nucleic acid used was single or double stranded. For in vivo studies, whole body autoradiography was used to monitor the bio-distribution of either free tritium-labelled ODN or that entrapped within PLGA microspheres following subcutaneous administration in Balb-c mice. The majority of the radioactivity associated with free ODN was eliminated within 24 h whereas polymer-released ODN persisted in organs and at the site of administration even after seven days post-administration. Polymer microsphere released ODN exhibited a similar tissue and cellular tropism to the free ODN. Micro-autoradiography analyses of the liver and kidneys showed similar bio-distribution for polymer-released and free ODNs with the majority of radioactivity being concentrated in the proximal convoluted tubules of the kidney and in the Kupffer cells of the liver. These findings suggest that biodegradable PLGA microspheres offer a method for improving the in vivo sustained delivery of gene silencing nucleic acids, and hence are worthy of further investigation as delivery systems for these macromolecules.     

Identification of a gene that affects the efficiency of host cell infection by Legionella pneumophila in a temperature-dependent fashion

The ability to infect host cells is critical for the survival and replication of intracellular pathogens in humans. We previously found that many genes involved in the ability of Legionella pneumophila to infect macrophages are not expressed efficiently under standard laboratory growth conditions. We have developed an approach using expression of L. pneumophila genes from an exogenous constitutive promoter on a low-copy-number vector that allows identification of genes involved in host cell infection. Through the use of this strategy, we found that expression of a gene, lvhB2, enhances the efficiency of L. pneumophila infection of mammalian cells. The putative protein encoded by lvhB2 has similarity to structural pilin subunits of type IV secretion systems. We confirmed that this gene plays a role in host cell infection by the construction of an in-frame deletion in the L. pneumophila lvhB2 gene and complementation of this mutant with the wild-type gene. The lvhB2 mutant does not display a very obvious defect in interactions with host cells when the bacteria are grown at 37 degrees C, but it has an approximately 100-fold effect on entry and intracellular replication when grown at 30 degrees C. These data suggest that lvhB2 plays an important role in the efficiency of host cell infection by L. pneumophila grown at lower temperatures.     

Maternal cerebral blood flow changes in pregnancy

OBJECTIVE: This study was undertaken to determine blood flow changes in the large cerebral arteries during normal pregnancy. STUDY DESIGN: Ten healthy pregnant volunteers underwent velocity-encoded phase contrast magnetic resonance imaging at 4 time intervals: 14 to 16, 28 to 32, and 36 to 38 weeks' gestation, and at 6 to 8 weeks' postpartum. Analysis consisted of serial paired Student t tests, with P<.05 considered significant. RESULTS: By using postpartum values for comparison, cerebral blood flow decreased by 14 to 16 weeks in the middle cerebral artery (P<.001), but was not significantly changed in the posterior cerebral artery. Significant decreases occurred in both the middle (P<.0001) and posterior (P=.002) cerebral arteries in late pregnancy. CONCLUSION: An approximately 20% reduction in large artery cerebral blood flow occurs during normal pregnancy, secondary to changes in velocity, whereas the area of these vessels remains unchanged. These findings may represent generalized vasodilatation of downstream resistance arterioles, assuming constant blood flow at the tissue level.     

Calcium needs in hemodialyzed-parathyroidectomized patients

Parathyroidectomy changes the homeostasis of calcium balance in patients under dialysis for kidney failure. The aim of this work is to value calcium needs in 20 hemodialysed patients who underwent parathyroidectomy, in the department of nephrology of UHC Ibn Rochd of Casablanca from January 1994 to June 1999. These patients, 12 women (60%) and 8 men (40%), aged between 14 and 70 years (mean=46.10+/-13.62 years). Hungry bone syndrome was noted in 8 patients and postoperative hypocalcemia in 15 (75%). Mean minimal serum calcium was 196+/-0.21 mmol/l, with clinical signs in 6 patients. Mean calcium supplement the first postoperative week was 18.1+/-0,54 g/day in the 8 patients with hungry bone syndrome and 14.28+/-0,86 g/day in the 12 remaining patients. Between 6 and 18 months postoperatively, required calcium supplementation was 4.5 to 12 g/day in patients with hungry bone syndrome compared with 3 to 6g/day at the remaining patients. Mean serum calcium remained stable between 2.16 mmol/l to the 3(rd) month and 2.48 mmol/l to the 36(th) month. Postoperative hypocalcemia remains a major concern after parathyroidectomy requiring massive substitution with calcium and active vitamin D metabolite under close supervision to spare these patients from hypercalcemia resulting from parathyroid dysfunction.