Determinants of mortality in non-neutropenic ICU patients with candidaemia

Introduction: Candidaemia in critically-ill intensive care unit (ICU) patients is associated with high crude mortality. Determinants of mortality – particularly those amenable to potential modification – are incompletely defined. Methods: A nationwide prospective clinical and microbiological cohort study of all episodes of ICU-acquired candidaemia occurring in non-neutropenic adults was undertaken in Australian ICUs between 2001 and 2004. Multivariate Cox regression analyses were performed to determine independently significant variables associated with mortality. Results: 183 episodes of ICU-acquired candidaemia occurred in 183 patients during the study period. Of the 179 with microbiological data, Candida albicans accounted for 111 (62%) episodes and Candida glabrata, 32 (18%). Outcome data were available for 173: crude hospital mortality at 30 days was 56%. Host factors (older age, ICU admission diagnosis, mechanical ventilation and ICU admission diagnosis) and failure to receive systemic antifungal therapy were significantly associated with mortality on multivariate analysis. Among the subset who received initial fluconazole therapy (n = 93), the crude mortality was 52%. Host factors (increasing age and haemodialysis receipt), but not organism- (Candida species, fluconazole MIC), pharmacokinetic- (fluconazole dose, time to initiation), or pharmacodynamic-related parameters (fluconazole dose:MIC ratio) were associated with mortality. Process of care measures advocated in recent guidelines were implemented inconsistently: follow-up blood cultures were obtained in 68% of patients, central venous catheters removed within five days in 80% and ophthalmological examination performed in 36%. Conclusions: Crude mortality remains high in Australian ICU patients with candidaemia and is overwhelmingly related to host factors but not treatment variables (the time to initiation of antifungals or fluconazole pharmacokinetic and pharmacodynamic factors). The role and timing of early antifungal intervention in critically-ill ICU patients requires further investigation.Deborah J.E. Marriott, E. Geoffrey Playford, Sharon Chen, Monica Slavin, Quoc Nguyen, David Ellis and Tania C. Sorrell for the Australian Candidaemia Stud

DNA-PK promotes the survival of young neurons in the embryonic mouse retina.

Supplementary Information accompanies the paper on Cell Death and Differentiation website: http://www.nature.com/cdd/journal/v17/n11/suppinfo/cdd201046s1.htmlProgrammed cell death is a crucial process in neural development that affects mature neurons and glial cells, as well as proliferating precursors and recently born neurons at earlier stages. However, the regulation of the early phase of neural cell death and its function remain relatively poorly understood. In mouse models defective in homologous recombination or nonhomologous end-joining (NHEJ), which are both DNA double-strand break (DSB) repair pathways, there is massive cell death during neural development, even leading to embryonic lethality. These observations suggest that natural DSBs occur frequently in the developing nervous system. In this study, we have found that several components of DSB repair pathways are activated in the developing mouse retina at stages that coincide with the onset of neurogenesis. In short-term organotypic retinal cultures, we confirmed that the repair pathways can be modulated pharmacologically. Indeed, inhibiting the DNA-dependent protein kinase (DNA-PK) catalytic subunit, which is involved in NHEJ, with NU7026 increased caspase-dependent cell death and selectively reduced the neuron population. This observation concurs with an increase in the number of apoptotic neurons found after NU7026 treatment, as also observed in the embryonic scid mouse retina, a mutant that lacks DNA-PK catalytic subunit activity. Therefore, our results implicate the generation of DSB and DNA-PK-mediated repair in neurogenesis in the developing retina.This work was supported by the Ministerio de Ciencia e Innovación, Spain (Grant SAF2007–66175 to EJdlR). JB is an FPI Fellow (Ministerio de Ciencia e Innovación).Peer reviewe

Early striatal hyperexcitability in an<i>in vitro</i>human striatal microcircuit model carrying the Parkinson’s<i>GBA-N370S</i>mutation

AbstractUnderstanding medium spiny neuron (MSN) physiology is essential to understand motor impairments in Parkinson’s disease (PD) given the architecture of the basal ganglia. Here, we developed a custom three-chamber microfluidic platform and established a cortico-striato-nigral microcircuit recapitulating the striatal presynaptic triadin vitrousing induced pluripotent stem cell (iPSC)-derived neurons. We found that, although cortical glutamatergic projections facilitated MSN synaptic activity, dopaminergic transmission was essential for excitability maturation of MSNsin vitro. Replacement of wild-type iPSC-dopamine neurons (iPSC-DaNs) in the striatal microcircuit with those carrying the PD-relatedGBA-N370Smutation induced early hyperexcitability in iPSC-MSNs through reduction of voltage-gated sodium and potassium intrinsic currents. Such deficits were resolved in aged cultures or with antagonism of protein kinase A activity in nigrostriatal iPSC-DaNs. Hence, our results highlight the unique utility of modelling striatal neurons in a modular and highly physiological circuit which is essential to reveal mechanistic insights of the loss of electrical functional integrity in the striata ofGBA1PD patients.</jats:p

A commercial ELISA detects high levels of human H5 antibody but cross-reacts with influenza A antibodies

Background and objectives: Commercial serological assays to determine influenza A H5N1 infection are available, although the accuracy and reproducibility of these are not reported in detail. This study aimed to assess the validity of a commercial ELISA H5 hemagglutinin (HA) antibody kit. Study design: A commercial ELISA for detection of antibodies towards influenza A H5 HA was evaluated using human sera from vaccinated individuals. The ELISA was used to screen 304 sera with elevated influenza A complement fixation titres collected between the period 1995-2007. Results and conclusions: The ELISA was found to be accurate for sera with high levels of anti-H5 antibodies, and would be useful in clinical settings where a rapid result is required. Thirteen of the stored sera were positive using the ELISA, but were confirmed as negative for H5N1 exposure using further serological tests. Absorption studies suggested that antibodies towards seasonal H3N2 and H1N1 influenza may cross-react with H5 antigen, giving false positive results with the ELISA. © 2008 Elsevier B.V. All rights reserved

Early striatal hyperexcitability in an in vitro human striatal microcircuit model carrying the Parkinson's GBA-N370S mutation

&lt;p&gt;&lt;strong&gt;ABSTRACT&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;Understanding medium spiny neuron (MSN) physiology is essential to understand motor impairments in Parkinson&rsquo;s disease (PD) given the architecture of the basal ganglia. Here, we developed a custom three-chamber microfluidic platform and established a cortico-striato-nigral microcircuit recapitulating the striatal presynaptic triad&nbsp;&lt;em&gt;in vitro&lt;/em&gt;&nbsp;using induced pluripotent stem cell (iPSC)-derived neurons. We found that, although cortical glutamatergic projections facilitated MSN synaptic activity, dopaminergic transmission was essential for excitability maturation of MSNs&nbsp;&lt;em&gt;in vitro&lt;/em&gt;. Replacement of wild-type iPSC-dopamine neurons (iPSC-DaNs) in the striatal microcircuit with those carrying the PD-related&nbsp;&lt;em&gt;GBA-N370S&lt;/em&gt;&nbsp;mutation induced early hyperexcitability in iPSC-MSNs through reduction of voltage-gated sodium and potassium intrinsic currents. Such deficits were resolved in aged cultures or with antagonism of protein kinase A activity in nigrostriatal iPSC-DaNs. Hence, our results highlight the unique utility of modelling striatal neurons in a modular and highly physiological circuit which is essential to reveal mechanistic insights of the loss of electrical functional integrity in the striata of&nbsp;&lt;em&gt;GBA1&lt;/em&gt;&nbsp;PD patients.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;FILE DESCRIPTIONS&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;Source Data.xlsx: Tabular datasets plotted on main figures 1, 3, 4, 5 and 6.&lt;/p&gt; &lt;p&gt;Supplementary Data.xlsx: Tabular datasets plotted on supplementary figures 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, and 12.&lt;/p&gt; &lt;p&gt;Key Resources Table.xlsx: Table containing key resources (primary and secondary antibodies, cell lines and software) used in this study.&lt;/p&gt; &lt;p&gt;List of Primers.xlsx: Primers used in&nbsp;RT-qPCR.&lt;/p&gt

Early deficits in an in vitro striatal microcircuit model carrying the Parkinson’s GBA-N370S mutation

Abstract Understanding medium spiny neuron (MSN) physiology is essential to understand motor impairments in Parkinson’s disease (PD) given the architecture of the basal ganglia. Here, we developed a custom three-chambered microfluidic platform and established a cortico-striato-nigral microcircuit partially recapitulating the striatal presynaptic landscape in vitro using induced pluripotent stem cell (iPSC)-derived neurons. We found that, cortical glutamatergic projections facilitated MSN synaptic activity, and dopaminergic transmission enhanced maturation of MSNs in vitro. Replacement of wild-type iPSC-derived dopamine neurons (iPSC-DaNs) in the striatal microcircuit with those carrying the PD-related GBA-N370S mutation led to a depolarisation of resting membrane potential and an increase in rheobase in iPSC-MSNs, as well as a reduction in both voltage-gated sodium and potassium currents. Such deficits were resolved in late microcircuit cultures, and could be reversed in younger cultures with antagonism of protein kinase A activity in iPSC-MSNs. Taken together, our results highlight the unique utility of modelling striatal neurons in a modular physiological circuit to reveal mechanistic insights into GBA1 mutations in PD