Comparative before-after study of fever prevention versus targeted temperature management following out-of-hospital cardiac arrest

Background

International guidelines for neuroprotection following out-of-hospital cardiac arrest (OHCA) recommend fever prevention ahead of routine temperature management. This study aimed to identify any effect of changing from targeted temperature management to fever prevention on neurological outcome following OHCA.

Methods

A retrospective observational cohort study was conducted of consecutive admissions to an ICU at a tertiary OHCA centre. Comparison was made between a period of protocolised targeted temperature management (TTM) to 36 °C and a period of fever prevention.

Results

Data were available for 183 patients. Active temperature management was administered in 86/118 (72%) of the TTM cohort and 20/65 (31%) of the fever prevention group. The median highest temperature prior to the start of temperature management was significantly lower in the TTM group at 35.6 (IQR 34.9-36.2) compared to 37.9 °C (IQR 37.7-38.2) in the fever prevention group (adjusted p < 0.001).There was no difference in the proportion of patients discharged with Cerebral Performance Category 1 or 2 between the groups (42% vs. 40%, p = 0.88). Patients in the fever prevention group required a reduced duration of noradrenaline (36 vs. 46 h, p = 0.03) and a trend towards a reduced duration of propofol (37 vs. 56 h, p = 0.06).In unadjusted analysis, use of active temperature management (irrespective of group) appeared to be associated with decreased risk of poor outcome (OR = 0.43, 95% CI 0.23-0.78) but after adjustment for patient age, presenting rhythm, witnessed arrest and duration of CPR, this was no longer significant (OR = 0.93, 95% CI 0.37-2.31, p = 0.88).

Conclusion

Switching from TTM to fever prevention following OHCA was associated with similar rates of neurological outcomes, with a possible decrease in sedation and vasopressor requirements.

Quantifying hospital environmental ventilation using carbon dioxide monitoring - a multicentre study

The COVID-19 pandemic has highlighted the importance of environmental ventilation in reducing airborne pathogen transmission. Carbon dioxide monitoring is recommended in the community to ensure adequate ventilation. Dynamic measurements of ventilation quantifying human exhaled waste gas accumulation are not conducted routinely in hospitals. Instead, environmental ventilation is allocated using static hourly air change rates. These vary according to the degree of perceived hazard, with the highest change rates reserved for locations where aerosol-generating procedures are performed, where medical/anaesthetic gases are used and where a small number of high-risk infective or immunocompromised patients may be isolated to reduce cross-infection. We aimed to quantify the quality and distribution of ventilation in hospital by measuring carbon dioxide levels in a two-phased prospective observational study. First, under controlled conditions, we validated our method and the relationship between human occupancy, ventilation and carbon dioxide levels using non-dispersive infrared carbon dioxide monitors. We then assessed ventilation quality in patient-occupied (clinical) and staff break and office (non-clinical) areas across two hospitals in Scotland. We selected acute medical and respiratory wards in which patients with COVID-19 are cared for routinely, as well as ICUs and operating theatres where aerosol-generating procedures  are performed routinely. Between November and December 2022, 127,680 carbon dioxide measurements were obtained across 32 areas over 8 weeks. Carbon dioxide levels breached the 800 ppm threshold for 14% of the time in non-clinical areas vs. 7% in clinical areas (p < 0.001). In non-clinical areas, carbon dioxide levels were > 800 ppm for 20% of the time in both ICUs and wards, vs. 1% in operating theatres (p < 0.001). In clinical areas, carbon dioxide was > 800 ppm for 16% of the time in wards, vs. 0% in ICUs and operating theatres (p < 0.001). We conclude that staff break, office and clinical areas on acute medical and respiratory wards frequently had inadequate ventilation, potentially increasing the risks of airborne pathogen transmission to staff and patients. Conversely, ventilation was consistently high in the ICU and operating theatre clinical environments. Carbon dioxide monitoring could be used to measure and guide improvements in hospital ventilation.

Prostatic stromal tumour of uncertain malignant potential treated with robotic-assisted radical prostatectomy: medium-term oncological and functional outcome of two cases

Stromal tumour of uncertain malignant potential (STUMP) is a rare tumour of the prostate with variable and unpredictable risk and clinical progression. There is no clear consensus on how it should be managed. We describe two cases of patients who presented to their general practitioners with raised prostate-specific antigen in one instance and an abnormal digital rectal examination in the other. Biopsies were carried out and a diagnosis of STUMP was made. Both cases were managed with robot-assisted radical prostatectomy and after 4.8 years of follow-up, there has not been any recurrence. This is the first reported UK case in which STUMP has been successfully managed with robotic surgery with excellent medium-term results. Radical prostatectomy can be used to treat STUMP tumour with good oncological and functional outcomes.

Stakeholder Engagement Strategies for Policy and Programmatic Uptake: Lessons from the Drivers of Food Choice Competitive Grants Program

Objectives

This study drew upon experiences of stakeholder engagement in food choice research to advance knowledge about best practices.

Methods

The Drivers of Food Choice Competitive Grants Program aimed to understand food choice in low- and middle-income-countries. All funded proposals included stakeholder engagement strategies. Data were from document review of proposals and reports and semi-structured interviews with the principal investigators of the 15 projects. Interviews were transcribed and uploaded into NVIVO 12. The lead author analyzed interviews thematically using an a priori code list and led discussion of themes and patterns through peer review with co-authors.

Results

Grantees developed and implemented a range of strategies. “Uni-directional” strategies were researcher-driven and informational, did not seek input from the target stakeholder, and included one-way communication such as emails, newsletters, meetings, press releases, technical briefs, newspaper articles, and public engagement efforts. “Bi-directional” strategies sought collaboration with stakeholders. Examples were workshops which sought feedback on stakeholder identification, research questions, methods, results, and recommendations. Grantees used unidirectional strategies to increase buy-in and generate demand for results, which helped promote the use of evidence for decision-making. Bi-directional strategies were integral to knowledge production. Grantees thought that bi-directional engagement enhanced the immediate applicability of the research. Grantees developed more- and less-intensive strategies that involved both bi-and uni-directional engagement, depending on goals for uptake.

Conclusions

This research sheds light on the role of stakeholder engagement strategies in advancing multisectoral nutrition. The current landscape of research and practice is fast-paced and complex; ensuring relevance of research via diverse stakeholder engagement strategies should remain a priority for researchers and funders. Our findings may aid researchers in constructing strategies that are responsive to diverse research programs and goals within complex multisectoral nutrition landscapes.

Funding Sources

UK Government's Department for International Development and Bill & Melinda Gates Foundation.

Effect of biochar amendment on sorption-desorption and dissipation of 17α‑ethinylestradiol in sandy loam and clay soils

Animal manure application in agricultural land has caused the release of steroid estrogens in the soil environment and further movement to aquatic systems. The objective of this study was to investigate the effects of biochar addition on sorption-desorption and dissipation behaviors of 17α‑ethinylestradiol (EE2) in two different textured soils. A Commerce sandy loam and a Shakey clay were selected and subjected to sterilization. Soil samples with and without sterilization were reacted with a series of EE2 solutions of different concentrations for sorption followed by desorption and quantification using HPLC-MS/MS. Long-term dissipation of EE2 in the same soils was also evaluated over a 30-d incubation. Biochar amendment increased the maximum EE2 sorption capacity but decreased its water desorption in both sandy loam and clay soils. On other hand, biochar addition increased the K_oc in the clay soil which had low EE2 sorption efficiency but decreased K_oc in the sandy loam which had high EE2 sorption efficiency. Biochar did significantly increase both desorbable and non-extractable fractions of EE2, while it reduced the bioavailability of EE2 to microbial degradation. The dissipation of EE2 in non-sterilized soils fit to the first-order kinetic model, whereas it was better described by zero-order kinetic for sterilized soil. Biochar increased the half-life of EE2 dissipation in non-sterilized Commerce sandy loam soil by 48% (from 3.63 to 5.37 d) and in non-sterilized Sharkey clay soil by 67% (from 2.28 to 3.81 d). Overall, this study demonstrated positive impacts of biochar on the retention of estrogen hormones in soils.

Implementation Research to Understand and Target Complex Needs: A Case Study of US-based Food Assistance Programming (P10-147-19)

Objectives

The objective of this study was to understand needs among seniors for food and food assistance and to develop a comprehensive taxonomy for these needs.

Methods

A total of 147 seniors were purposively sampled from 12 food-assistance programs in 9 states. Of the 12 programs, 10 provided unprepared foods and 2 provided pre-cooked meals. Data were semi-structured qualitative interviews. Coding and analysis of transcripts followed an inductive qualitative analysis approach. A series of thematic summaries were prepared to reflect the content of the interviews for discussion and refinement of the analytic approach.

Results

An emergent taxonomy comprised 3 categories consisting of abilities and ranges or variants of those abilities. The category of physical ability consists of physical strength, the ability to prepare food, the ability to walk or stand, and health status. These relate to an individual's functional abilities to live and act independently and may be considered pre-conditions for program uptake and benefit distinct from dietary and food security-related needs and limitations. The category of consuming food consists of preferences, accessibility, affordability, and dietary needs. This category highlights the relationship between economic constraints and dietary needs that often necessitates meaningful tradeoffs in consuming the right foods for their health. The category of access and use of transportation consists of own means, friends or family, and public or private services. This category highlights challenges in accessing programs and provides insight into seniors’ experiences of poverty, declining functional abilities, social networks and connectedness, geography, and public services.

Conclusions

The process used to develop the taxonomy and the taxonomy itself provide an exemplar for implementation research when the nature of need is complex and programs integrated across sectors are required to address the need. The taxonomy provides structure to facilitate the identification of key factors in program engagement—and insight into the economic and social environments in which they occur—that translate into needs relevant to the design, targeting, and uptake of food assistance in a diverse population of seniors.

Funding Sources

Enterprise Rent-a-Car Foundation.

Injury profiles in elite women's T20 cricket

OBJECTIVES

To Describe the injury incidence and prevalence during two years of a professional women's T20 cricket tournament.

DESIGN

Prospective cohort study.

METHODS

Injuries were recorded prospectively for 68 matches during a professional women's T20 tournament in 2016 and 2017. There were six teams of 15 players. Participants were female, aged between 16-38 years (mean 23.4±4.8). Time-loss and non time-loss incidence and prevalence were calculated for match days, region, skill group, mode and activity at time of injury.

RESULTS

The greatest incidence occurred in the shoulder (1.8 injuries per 100 match days), lower back (1.7 injuries per 100 match days) and knee (1.7 injuries per 100 match days). The highest time-loss prevalence occurred in hand (1.7%), head/face (0.8%) and thigh (0.6%). All head injuries were concussion. Catching related injuries caused the most time-loss (2.5% prevalence) and throwing related shoulder injury had the highest incidence (2.3 injuries per 100 match days). Gradual onset injuries had the highest overall incidence (7.9 injuries per 100 match days).

CONCLUSIONS

In elite female T20 cricket, time-loss injuries, particularly impact/traumatic injuries are most likely to occur during fielding, suggesting pitch side support and trauma training is a priority. The high incidence of gradual onset injuries, particularly throwing related shoulder pain, indicates that managing workload and ensuring physical preparedness is vital.

Clinical management and research priorities for high-risk prostate cancer in the UK: Meeting report of a multidisciplinary panel in conjunction with the NCRI Prostate Cancer Clinical Studies Localised Subgroup

The management of high-risk prostate cancer has become increasingly sophisticated, with refinements in radical therapy and the inclusion of adjuvant local and systemic therapies. Despite this, high-risk prostate cancer continues to have significant treatment failure rates, with progression to metastasis, castrate resistance and ultimately disease-specific death. In an effort to discuss the challenges in this field, the UK National Clinical Research Institute’s Prostate Cancer Clinical Studies localised subgroup convened a multidisciplinary national meeting in the autumn of 2014. The remit of the meeting was to debate and reach a consensus on the key clinical and research challenges in high-risk prostate cancer and to identify themes that the UK would be best placed to pursue to help improve outcomes. This report presents the outcome of those discussions and the key recommendations for future research in this highly heterogeneous disease entity.

The Prostate Health Index adds predictive value to multi-parametric MRI in detecting significant prostate cancers in a repeat biopsy population

Both multi-parametric MRI (mpMRI) and the Prostate Health Index (PHI) have shown promise in predicting a positive biopsy in men with suspected prostate cancer. Here we investigated the value of combining both tests in men requiring a repeat biopsy. PHI scores were measured in men undergoing re-biopsy with an mpMRI image-guided transperineal approach (n = 279, 94 with negative mpMRIs). The PHI was assessed for ability to add value to mpMRI in predicting all or only significant cancers (Gleason ≥7). In this study adding PHI to mpMRI improved overall and significant cancer prediction (AUC 0.71 and 0.75) compared to mpMRI + PSA alone (AUC 0.64 and 0.69 respectively). At a threshold of ≥35, PHI + mpMRI demonstrated a NPV of 0.97 for excluding significant tumours. In mpMRI negative men, the PHI again improved prediction of significant cancers; AUC 0.76 vs 0.63 (mpMRI + PSA). Using a PHI≥35, only 1/21 significant cancers was missed and 31/73 (42%) men potentially spared a re-biopsy (NPV of 0.97, sensitivity 0.95). Decision curve analysis demonstrated clinically relevant utility of the PHI across threshold probabilities of 5-30%. In summary, the PHI adds predictive performance to image-guided detection of clinically significant cancers and has particular value in determining re-biopsy need in men with a negative mpMRI.

Suicidal emperipolesis: a process leading to cell-in-cell structures, T cell clearance and immune homeostasis

"Suicidal emperipolesis" is one of the most recently reported processes leading to cell-in-cell structures that promote cell death. This process was discovered in studies investigating the fate of autoreactive CD8 T cells activated within the liver. Recently, we reported that activated T cells invaded hepatocytes, formed transient cell-in-cell structures, and were rapidly degraded within endosomal/lysosomal compartments by a non-apoptotic pathway. Importantly, pharmacological inhibition of this process caused intrahepatic accumulation of tissue-reactive T cells and breach of immune tolerance. The characterization of the molecular mechanisms of suicidal emperipolesis is still in its infancy, but initial studies suggest this phenomenon is distinct from other reported cell-in-cell structures. As opposed to the formation of other cell-in-cell structures, suicidal emperipolesis takes place in a non-malignant environment, and without obvious pathology. It is therefore the first cell-in-cell structure described to have a role in maintaining homeostasis in normal physiology in higher organisms. T cell emperipolesis within hepatocytes has also been observed by pathologists in a range of chronic human liver pathologies. As T cell-in-hepatocyte structures resulting from suicidal emperipolesis are very transiently observed in normal physiology, their accumulation during liver disease would suggest that severe tissue injury is promoted by, or associated with, defective T cell clearance. In this review, we compare "suicidal emperipolesis" to other processes leading to cell-in-cell structures, and consider its potential biological roles in maintaining immune homeostasis and tolerance in the context of the hepatic environment.

Adverse effects of anti-tuberculosis drugs on HepG2 cell bioenergetics

Tuberculosis (TB) is an intractable chronic infection. Disease treatment with anti-TB drugs remains challenging due to drug-induced hepatotoxicity. The toxicity of the anti-TB drugs rifampicin (RIF), isoniazid (INH) and pyrazinamide (PZA) either alone or in combination was investigated in HepG2 cells. Assays of intracellular adenosine triphosphate (ATP) levels at 4-, 24- and 48-h post-exposure to gradient concentrations of RIF, INH and PZA were conducted. Drug-induced effects on mitochondrial membrane potential (MMP), mitochondrial complex I and complex III activity, nicotinamide adenine dinucleotide (NAD⁺) levels and cellular lactate production were assessed. Decreased ATP levels were dose-dependent and correlated with drug exposure duration. Approximate 24-h IC₅₀s were 0.5 mM, 70 mM and 84 mM for RIF, INH and PZA, respectively. Twenty-four hours post-drug treatment, reductions of MMP ( p = 0.0005), mitochondrial complex I and III activities ( p = 0.0001 and p = 0.0003, respectively), NAD⁺ levels ( p = 0.0057) and increased lactate production ( p < 0.0001) were observed. Drug combinations used to mimic cumulative drug treatments induced a synergistic inhibition of mitochondrial complex I activity. An assessment of cellular ultrastructure using transmission electron microscopy indicated drug-induced mitophagy. Collectively, our study suggests that hepatotoxicity of commonly employed anti-TB drugs is mediated by their curtailment of mitochondrial function.

The Effect of Umbilical Cord Milking on Hemodynamic Status of Preterm Infants: A Randomized Controlled Trial

BACKGROUND: Delayed cord clamping may be difficult to perform in extremely preterm infants. The effects of the alternative, cord milking, have not been fully evaluated.

OBJECTIVES: To determine whether cord milking (CM) at birth improves systemic blood flow and short term outcomes, as compared with immediate cord clamping (ICC).

DESIGN/METHODS: Babies born to eligible, consenting women presenting in preterm labor between 24 and 31 weeks' gestation were randomized to receive CM or ICC. Echocardiography was performed at 4-6 and 10-12 hours after birth. The primary outcome was systemic blood flow as represented by echo-derived superior vena cava (SVC) flow. Neonatal care staff, echogardiographer and interpreter were blind to the randomization. Analysis was by intention to treat.

RESULTS: A total of 73 eligible infants were randomized (37 to CM and 36 to ICC) during the study period (November 2011-2014). There were no statistically significant differences in maternal demographic and antenatal variables. Mean (SD) gestational age was 26.1 (11) weeks and mean (SD) birth weight was 1025 (308) g. 38% of infants were born by vaginal delivery. No significant differences were found between groups in SVC flow, cardiac outputs or neonatal morbidities [table1].

CONCLUSION: There were no statistically significant differences in functional cardiac outcomes, mortality or morbidity between preterm infants who received CM and those who received ICC. Larger trials are needed to establish the best practice in managing the umbilical cord at birth in extremely preterm infants.

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Histopathologic Features, Immunophenotyping, Clonality, and Eubacterial Fluorescence In Situ Hybridization in Cats With Lymphocytic Cholangitis/Cholangiohepatitis

Feline lymphocytic cholangitis is a poorly characterized disease complex with respect to histologic lesions, immunophenotype, and etiopathogenesis. Seventy-eight cases of feline lymphocytic cholangitis ( n = 51) and feline hepatic lymphoma ( n = 27) were reviewed using standardized histopathology, immunophenotyping (B cell and T cell), polymerase chain reaction for T-cell receptor (TCR) gene rearrangement, and fluorescence in situ hybridization (FISH) for eubacteria. Five histopathologic features in cases of lymphocytic cholangitis assisted in its differentiation from hepatic lymphoma: bile duct targeting ( n = 32, 62.7%), ductopenia ( n = 9, 17.6%), peribiliary fibrosis ( n = 37, 72.5%), portal B-cell aggregates ( n = 36, 70.6%), and portal lipogranulomas ( n = 38, 74.5%). The majority of lymphocytic cholangitis cases ( n = 35, 68.6%) were T cell predominant; 15 (29.4%) had an equal mix of B cells and T cells, and 1 (1.9%) had a B cell–predominant infiltrate; 66.6% of hepatic lymphoma cases were T-cell lymphomas. TCR clonality results were unexpected, with 17.1% of cases of lymphocytic cholangitis having clonal or oligoclonal populations and with T-cell lymphomas having variable TCR clonality (63.6% clonal or oligoclonal, 36.3% polyclonal). The majority of lymphocytic cholangitis ( n = 32 of 36, 88.8%) and all hepatic lymphoma cases had no detectable eubacteria using FISH. As demonstrated here, bile duct targeting, ductopenia, peribiliary fibrosis, portal B-cell aggregates, and portal lipogranulomas are lymphocytic cholangitis features that, along with polyclonal TCR (83%), help differentiate it from hepatic lymphoma. No strong evidence was found implicating in situ bacterial colonization as an etiopathogenesis of lymphocytic cholangitis.

Secretion of a bacterial cellulase by yeast

Gene fusions were constructed between a yeast expression plasmid and a Cellulomonas fimi DNA fragment encoding an endo-1,4-beta-D-glucanase or carboxymethylcellulase. Yeast transformed with the recombinant plasmids secreted carboxymethylcellulase activity. Secretion of active enzyme was greatly increased when the leader of a secreted yeast protein, the Kl toxin, was inserted immediately upstream of and in frame with the bacterial cellulase sequence. This is the first step in constructing a functional cellulase complex in Saccharomyces cerevisiae. It also provides an excellent system for the detailed examination of the determinants of protein secretion because of the ease with which secreted cellulase can be detected.

Alterations in liver sinusoidal endothelium in a baboon model of type 1 diabetes

AIMS/HYPOTHESIS

Diabetes mellitus is associated with extensive vascular pathology, yet little is known about its long-term effects on liver sinusoidal endothelial cells (LSECs). Potential diabetic changes in LSECs are important because of the role played by fenestrations in the LSECs in hepatic disposition of lipoproteins.

MATERIALS AND METHODS

Surgical liver biopsies for electron microscopy and immunohistochemistry were obtained from baboons with long-standing streptozotocin-induced, insulin-treated diabetes mellitus and compared with those from age-matched control animals.

RESULTS

There was an increase in the thickness of LSECs (170 +/- 17 vs 123 +/- 10 nm, p < 0.01). Fenestrations in LSECs, as determined by overall porosity, were markedly reduced (1.4 +/- 0.1% vs 2.6 +/- 0.2%, p < 0.01). Increased numbers of stellate cells were seen on electron microscopy, and this finding was corroborated by increased smooth muscle actin expression. Diabetes mellitus was also associated with increased endothelial production of von Willebrand factor and caveolin-1.

CONCLUSIONS/INTERPRETATION

Diabetes mellitus in the non-human primate is associated with marked changes in LSECs, including a reduction in fenestrations. Such changes provide an additional and novel mechanism for impaired hepatic lipoprotein clearance and post-prandial hyperlipidaemia in diabetes mellitus.

Comprehensive profiling and localisation of the matrix metalloproteinases in urothelial carcinoma

The matrix metalloproteinases (MMPs) are endopeptidases which break down the extracellular matrix and regulate cytokine and growth factor activity. Several MMPs have been implicated in the promotion of invasion and metastasis in a broad range of tumours including urothelial carcinoma. In this study, RNA from 132 normal bladder and urothelial carcinoma specimens was profiled for each of the 24 human MMPs, the four endogenous tissue inhibitors of MMPs (TIMPs) and several key growth factors and their receptors using quantitative real time RT–PCR. Laser capture microdissection (LCM) of RNA from 22 tumour and 11 normal frozen sections was performed allowing accurate RNA extraction from either stromal or epithelial compartments. This study confirms the over expression in bladder tumour tissue of well-documented MMPs and highlights a range of MMPs which have not previously been implicated in the development of urothelial cancer. In summary, MMP-2, MT1-MMP and the previously unreported MMP-28 were very highly expressed in tumour samples while MMPs 1, 7, 9, 11, 15, 19 and 23 were highly expressed. There was a significant positive correlation between transcript expression and tumour grade for MMPs 1, 2, 8, 10, 11, 12, 13, 14, 15 and 28 (P<0.001). At the same confidence interval, TIMP-1 and TIMP-3 also correlated with increasing tumour grade. LCM revealed that most highly expressed MMPs are located primarily within the stromal compartment except MMP-13 which localised to the epithelial compartment. This work forms the basis for further functional studies, which will help to confirm the MMPs as potential diagnostic and therapeutic targets in early bladder cancer.

Experimental study of interaction of laser radiation with silver nanoparticles in SiO2 matrix

Thin films of silica containing silver nanoparticles were deposited by magnetron co-sputtering followed by thermal annealing in air or Ar+2% H2. Laser fragmentation of the particles was carried out at two different wavelengths. The films were characterized by UV-VIS absorption spectroscopy and plasmon resonance numerical modeling based on the Mie theory, together with Rutherford backscattering elemental analysis, X-ray photoelectron spectroscopy chemical characterization, combined with statistical analysis of the transmission electron microscopy micrographs, and surface topography study by atomic force microscopy. It is demonstrated that the fragmentation is a result of a thermal process and its mechanism does not depend on the laser wavelength as long as the laser light is absorbed by the silver particles. Laser treatment with moderate fluences does not alter the precipitated metal content while fragmenting the particles. TEM study indicates that laser assisted silver particle modification can serve as a method for narrowing the particle size distribution.

N-methyl-d-aspartate receptor activation in human cerebral endothelium promotes intracellular oxidant stress

Cerebral endothelial cells in the rat, pig, and, most recently, human have been shown to express several types of receptors specific for glutamate. High levels of glutamate disrupt the cerebral endothelial barrier via activation of N-methyl-d-aspartate (NMDA) receptors. We have previously suggested that this glutamate-induced barrier dysfunction was oxidant dependent. Here, we provide evidence that human cerebral endothelial cells respond to glutamate by generating an intracellular oxidant stress via NMDA receptor activation. Cerebral endothelial cells loaded with the oxidant-sensitive probe dihydrorhodamine were used to measure intracellular reactive oxygen species (ROS) formation in response to glutamate receptor agonists, antagonists, and second message blockers. Glutamate (1 mM) significantly increased ROS formation compared with sham controls (30 min). This ROS response was significantly reduced by 1) MK-801, a noncompetitive NMDA receptor antagonist; 2) 8-( N, N-diethylamino)- n-octyl-3,4,5-trimethoxybenzoate, an intracellular Ca2+antagonist; 3) LaCl3, an extracellular Ca2+channel blocker; 4) diphenyleiodonium, a heme-ferryl-containing protein inhibitor; 5) itraconazole, a cytochrome P-450 3A4 inhibitor; and 6) cyclosporine A, which prevents mitochondrial membrane pore transition required for mitochondrial-dependent ROS generation. Our results suggest that the cerebral endothelial barrier dysfunction seen in response to glutamate is Ca2+dependent and may require several intracellular signaling events mediated by oxidants derived from reduced nicotinamide adenine dinucleotide oxidase, cytochrome P-450, and the mitochondria.

The effect of aging on the immunohistochemistry of apolipoprotein E in the liver

Apolipoprotein E (apoE) is involved in hepatic disposition of chylomicron remnants, which is impaired in old age. Isoforms of apoE have been implicated in age-related diseases and possibly the aging process itself. Because the effects of old age on expression and distribution of apoE in the liver have not been reported, we studied the effect of old age on the immunohistochemistry of apoE in the livers of humans and the non-human primate, Papio hamadryas. Overall, old age was not associated with marked changes in the expression of apoE between adult (48+/-19 years) and old (82+/-5 years) humans. However, there was a change in the distribution of apoE staining. The livers of older humans displayed increased hepatocyte cytoplasmic staining and reduced peri-sinusoidal staining. Similar trends were noted in the livers from the baboons. Such findings are suggestive of altered apoE recycling in old age and have implications for age-related dyslipidaemia.

Glutamate causes a loss in human cerebral endothelial barrier integrity through activation of NMDA receptor

l-Glutamate is a major excitatory neurotransmitter that binds ionotropic and metabotropic glutamate receptors. Cerebral endothelial cells from many species have been shown to express several forms of glutamate receptors; however, human cerebral endothelial cells have not been shown to express either the N-methyl-D-aspartate (NMDA) receptor message or protein. This study provides evidence that human cerebral endothelial cells express the message and protein for NMDA receptors. Human cerebral endothelial cell monolayer electrical resistance changes in response to glutamate receptor agonists, antagonists, and second message blockers were tested. RT-PCR and Western blot analysis were used to demonstrate the presence of the NMDA receptor. Glutamate and NMDA (1 mM) caused a significant decrease in electrical resistance compared with sham control at 2 h postexposure; this response could be blocked significantly by MK-801 (an NMDA antagonist), 8-(N,N-diethylamino)-n-octyl-3,4,5-trimethyoxybenzoate (an intracellular Ca2+ antagonist), and N-acetyl-L-cystein (an antioxidant). Trans(+/-)-1-amino-1,3-cyclopentanedicarboxylic acid, a metabotropic receptor agonist (1 mM), did not significantly decrease electrical resistance. Our results are consistent with a model where glutamate, at excitotoxic levels, may lead to a breakdown in the blood brain barrier via activation of NMDA receptors.

Human neuroepithelial cells express NMDA receptors

L-glutamate, an excitatory neurotransmitter, binds to both ionotropic and metabotropic glutamate receptors. In certain parts of the brain the BBB contains two normally impermeable barriers: 1) cerebral endothelial barrier and 2) cerebral epithelial barrier. Human cerebral endothelial cells express NMDA receptors; however, to date, human cerebral epithelial cells (neuroepithelial cells) have not been shown to express NMDA receptor message or protein. In this study, human hypothalamic sections were examined for NMDA receptors (NMDAR) expression via immunohistochemistry and murine neuroepithelial cell line (V1) were examined for NMDAR via RT-PCR and Western analysis. We found that human cerebral epithelium express protein and cultured mouse neuroepithelial cells express both mRNA and protein for the NMDA receptor. These findings may have important consequences for neuroepithelial responses during excitotoxicity and in disease.

Predation of Cryptosporidium oocysts by protozoa and rotifers: implications for water quality and public health

Predation by free-living protozoa and rotifers was investigated as a possible mechanism for the removal of Cryptosporidium parvum oocysts in aquatic ecosystems including wastewater treatment plants. Free-living ciliated protozoa (Stylonychia mytilus, Paramecium caudatum and an unidentified wastewater wetland ciliate), an amoeba (Acanthamoeba culbertsoni) and rotifers, all commonly found in aquatic ecosystems, were exposed to varying doses of C. parvum oocysts. All organisms investigated ingested oocysts. Predation activity and rates of ingestion varied with predator species and prey density. Ciliated protozoa demonstrated greater predation activity than A. culbertsoni or rotifers when exposed to 2 x 10(5) oocyst/mL for up to 3 h. Greatest predation after 1 h exposure was observed in P. caudatum, the largest ciliate, with on average 1.9 oocysts/cell (range 0-9 oocysts/cell). Stylonychia mytilus and the wetland ciliate had a similar mean ingestion of around 0.3 oocysts/cell, with numbers internalised ranging from 0-3 oocysts/cell. Rotifers ingested on average 1.6 oocysts/individual (range 0-7 oocysts/individual) whilst amoebae ingested on average 1.8 oocysts/cell after 2 h exposure (up to 3 oocysts/cell). Grazing activity by P. caudatum was demonstrated at a variety of prey levels ranging from 9 to 9,000 oocysts. Numbers of oocysts internalised by Paramecium frequently exceeded the reported human infective dose of 30 oocysts. In general, numbers of internalised oocysts increased with incubation time of up to 20-30 min although the rate of accumulation was slower at lower dose levels. The significance of predation on the fate of Cryptosporidium oocysts in the environment is discussed.

Heart failure in patients admitted to hospital: mortality is still high

BACKGROUND: Two separate cohorts of consecutive patients admitted to hospital with a primary diagnosis of heart failure were studied, the first in 1986 in Rochdale, and the second in 1995 in Brighton. METHODS: We observed the clinical profile, treatment and mortality during hospital admission and reviewed their status at 6 months. There were 132 patients in the Rochdale cohort and 223 in the Brighton cohort. RESULTS: The Rochdale cohort was characterised by a lower mean age and longer hospital stay. Significant differences were also observed in co-morbidity and the use of ACE inhibitors, but hospital mortality was almost identical (25% in Rochdale and 24% in Brighton). A low systolic blood pressure, hyponatraemia, hyperkalaemia and a raised blood urea at presentation were independent adverse prognostic factors. In contrast, prior treatment with ACE inhibitors in patients with congestive cardiac failure led to a more favourable hospital outcome. Age, gender and co-morbidity did not affect mortality apart from patients with acute myocardial infarction. Follow-up of these cohorts showed that mortality of the two groups remained high at 180 days after admission (40% in Rochdale and 39% in Brighton). There were marked differences in the use of ACE inhibitors in survivors, but target doses of ACE inhibitors (enalapril 20 mg/day or equivalent) were only achieved in 31%, despite direct communication between the hospital and primary care physicians. CONCLUSIONS: Although clinical and treatment profiles differed between the two periods studied, the hospital and 6-month mortality of patients with heart failure remained high. More emphasis needs to be given to optimising ACE inhibitor use in primary care.

Computational analysis of Thr203 isomerization in green fluorescent protein

Green fluorescent protein (GFP) is an extensively used fluorescent tag. Photoisomerization between two spectroscopically distinct states in wild-type GFP is responsible for its two visible absorption bands at 398 nm (A) and 475 nm (B). We have used molecular mechanics and database analysis to support the suggestion of other researchers that the anionic form of the GFP chromophore is responsible for the B absorption band, while the phenol form is responsible for band A. The anionic (-Otyr, Nimid, Glu222H) species is the only form that has a low energy pathway allowing for isomerization of Thr203 to a conformation where it stabilizes the phenolate form and is therefore the most likely species responsible for the B absorption band. The rotation of the Thr203 side-chain is restricted; this may be significant in the formation of the intermediate state which is central to the photoisomerization. Our calculations support the most commonly accepted mechanism for photoisomerization, and we have shown that the 201LSTQS205 sequence does not allow a g+ conformation for Thr203.

Abundance, biomass and viability of bacteria in wastewaters: impact of treatment in horizontal subsurface flow constructed wetlands

The aims of this project were to assess bacterial populations (abundance, biomass and viability) in the influents and effluents of four constructed wetlands, and to analyse the effect of such biological treatment on these bacterial characteristics. Using the BacLight probe it was possible to determine the total abundance, the proportion of intact vs. damaged cells, and the lengths, widths and biovolumes, of bacteria in each of the samples. The reduction in bacterial concentration was higher (67%) in the wetland used for secondary treatment than in those used for tertiary treatment (15-39%). The proportion of damaged cells was higher in the influent (i.e. settled sewage) of the wetland used for secondary treatment (78%) than in the influents of those wetlands used for tertiary treatment (45-70%). This suggested that the majority of bacteria in the settled sewage were dead or damaged, and that these were removed from the wastewaters more effectively than were undamaged cells during conventional secondary treatment (in this case, using rotating biological contactors or RBCs). In each wetland, the proportion of damaged cells was higher in the influent than in the effluent, suggesting that, as with RBCs, damaged bacteria were removed more effectively within the wetland than undamaged bacteria. The majority of bacteria leaving the constructed wetlands used for tertiary treatment, and 50% of those leaving the secondary treatment wetland, were physically intact and therefore probably viable. Although there was a decrease in the abundance of total bacteria with treatment, bacterial biomass did not necessarily decrease with the treatment.