Photoreceptor Outer Segment-like Structures in Long-Term 3D Retinas from Human Pluripotent Stem Cells.

The retinal degenerative diseases, which together constitute a leading cause of hereditary blindness worldwide, are largely untreatable. Development of reliable methods to culture complex retinal tissues from human pluripotent stem cells (hPSCs) could offer a means to study human retinal development, provide a platform to investigate the mechanisms of retinal degeneration and screen for neuroprotective compounds, and provide the basis for cell-based therapeutic strategies. In this study, we describe an in vitro method by which hPSCs can be differentiated into 3D retinas with at least some important features reminiscent of a mature retina, including exuberant outgrowth of outer segment-like structures and synaptic ribbons, photoreceptor neurotransmitter expression, and membrane conductances and synaptic vesicle release properties consistent with possible photoreceptor synaptic function. The advanced outer segment-like structures reported here support the notion that 3D retina cups could serve as a model for studying mature photoreceptor development and allow for more robust modeling of retinal degenerative disease in vitro

A novel procedure for precise quantification of Schistosoma japonicum eggs in bovine feces

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin-ethyl acetate sedimentation-digestion (FEA-SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.This work was partially supported by the following grants: The National High Technology Research and Development Program of China (grant No. 2007AA02Z153), and National Science and Technology Major Program (grant Nos. 2009ZX10004-302, 2008ZX10004-011)

Plasma membrane damage removal by F-actin-mediated shedding from repurposed filopodia

Repairing plasma membrane damage is vital to eukaryotic cell survival. Membrane shedding is thought to be key to this repair process, but a detailed view of how the process occurs is still missing. Here we used electron cryotomography to image the ultrastructural details of plasma membrane wound healing. We found that filopodia-like protrusions are built at damage sites, accompanied by retraction of neighboring filopodia, and that these repurposed protrusions act as scaffolds for membrane shedding. This suggests a new role for filopodia as reservoirs of membrane and actin for plasma membrane damage repair. Damage-induced shedding was dependent on F-actin dynamics and Myo1a, as well as Vps4B, an important component of the ESCRT machinery. Thus we find that damage shedding is more complex than current models of simple vesiculation from flat membrane domains. Rather, we observe structural similarities between damage-mediated shedding and constitutive shedding from enterocytes that argue for conservation of a general membrane shedding mechanism

Factors associated with transition from community settings to hospital as place of death for adults aged 75 years or older: a population-based mortality follow-back survey

Objective: To identify factors associated with end of life (EoL) transition from usual place of care to hospital as place of death for people aged 75 years or older (75+). Design: Population-based mortality follow-back survey. Setting: Deaths over six months in 2012 in two unitary authorities in England, covering 800 square miles with over one million residents. Participants: A random sample of people aged 75+ who died in a care home or hospital and all those who died at home or in a hospice unit. Cases were identified from death registrations. The person who registered the death (a relative for 98.9%) completed the survey. Measurements: Our main outcome was EoL transition to hospital as place of death versus no EoL transition to hospital. We used multivariable modified Poisson regression to examine factors (illness, demographic and environmental) related to EoL transition to hospital. Results: 443/882 (50.2%) responded, describing the care received by people who died from mostly non-malignant conditions (76.3%) at mean age 87.4 years (SD= 6.4). 32.3% transitioned to hospital and died there (n=146). Transition was more likely in respiratory disease compared to cancer (Prevalence Ratio [PR] =2.07, 95%CI 1.42- 3.01) and for people with severe breathlessness (PR=1.96, 95%CI 1.12-3.43). Transition was less likely if EoL preferences had been discussed with a healthcare professional (PR=0.60, 95%CI 0.42-0.88) and when there was a key healthcare professional (PR=0.74, 95%CI 0.58-0.95). Conclusion: To reduce EoL transition to hospital for older people this study suggests a need to improve the symptom management of breathlessness in the community and better access to a key healthcare professional skilled in coordinating care, communication, facilitating complex discussions and in planning for future care

High sucrose consumption decouples intrinsic and synaptic excitability of AgRP neurons without altering body weight.

BACKGROUND/OBJECTIVE: As the obesity epidemic continues, the understanding of macronutrient influence on central nervous system function is critical for understanding diet-induced obesity and potential therapeutics, particularly in light of the increased sugar content in processed foods. Previous research showed mixed effects of sucrose feeding on body weight gain but has yet to reveal insight into the impact of sucrose on hypothalamic functioning. Here, we explore the impact of liquid sucrose feeding for 12 weeks on body weight, body composition, caloric intake, and hypothalamic AgRP neuronal function and synaptic plasticity. METHODS: Patch-clamp electrophysiology of hypothalamic AgRP neurons, metabolic phenotyping and food intake were performed on C57BL/6J mice. RESULTS: While mice given sugar-sweetened water do not gain significant weight, they do show subtle differences in body composition and caloric intake. When given sugar-sweetened water, mice show similar alterations to AgRP neuronal excitability as in high-fat diet obese models. Increased sugar consumption also primes mice for increased caloric intake and weight gain when given access to a HFD. CONCLUSIONS: Our results show that elevated sucrose consumption increased activity of AgRP neurons and altered synaptic excitability. This may contribute to obesity in mice and humans with access to more palatable (HFD) diets

Simulations suggest a constrictive force is required for Gram-negative bacterial cell division

To divide, Gram-negative bacterial cells must remodel cell wall at the division site. It remains debated, however, whether this cell wall remodeling alone can drive membrane constriction, or if a constrictive force from the tubulin homolog FtsZ is required. Previously, we constructed software (REMODELER 1) to simulate cell wall remodeling during growth. Here, we expanded this software to explore cell wall division (REMODELER 2). We found that simply organizing cell wall synthesis complexes at the midcell is not sufficient to cause invagination, even with the implementation of a make-before-break mechanism, in which new hoops of cell wall are made inside the existing hoops before bonds are cleaved. Division can occur, however, when a constrictive force brings the midcell into a compressed state before new hoops of relaxed cell wall are incorporated between existing hoops. Adding a make-before-break mechanism drives division with a smaller constrictive force sufficient to bring the midcell into a relaxed, but not necessarily compressed, state

The effectiveness and cost-effectiveness of hospital-based specialist palliative care for adults with advanced illness and their caregivers

BackgroundSerious illness is often characterised by physical/psychological problems, family support needs, and high healthcare resource use. Hospital‐based specialist palliative care (HSPC) has developed to assist in better meeting the needs of patients and their families and potentially reducing hospital care expenditure. There is a need for clarity on the effectiveness and optimal models of HSPC, given that most people still die in hospital and also to allocate scarce resources judiciously.ObjectivesTo assess the effectiveness and cost‐effectiveness of HSPC compared to usual care for adults with advanced illness (hereafter patients) and their unpaid caregivers/families.Search methodsWe searched CENTRAL, CDSR, DARE and HTA database via the Cochrane Library; MEDLINE; Embase; CINAHL; PsycINFO; CareSearch; National Health Service Economic Evaluation Database (NHS EED) and two trial registers to August 2019, together with checking of reference lists and relevant systematic reviews, citation searching and contact with experts to identify additional studies.Selection criteriaWe included randomised controlled trials (RCTs) evaluating the impact of HSPC on outcomes for patients or their unpaid caregivers/families, or both. HSPC was defined as specialist palliative care delivered by a palliative care team that is based in a hospital providing holistic care, co‐ordination by a multidisciplinary team, and collaboration between HSPC providers and generalists. HSPC was provided to patients while they were admitted as inpatients to acute care hospitals, outpatients or patients receiving care from hospital outreach teams at home. The comparator was usual care, defined as inpatient or outpatient hospital care without specialist palliative care input at the point of entry into the study, community care or hospice care provided outside of the hospital setting.Data collection and analysisWe used standard methodological procedures expected by Cochrane. We assessed risk of bias and extracted data. To account for use of different scales across studies, we calculated standardised mean differences (SMDs) with 95% confidence intervals (CIs) for continuous data. We used an inverse variance random‐effects model. For binary data, we calculated odds ratio (ORs) with 95% CIs. We assessed the evidence using GRADE and created a 'Summary of findings' table.Our primary outcomes were patient health‐related quality of life (HRQoL) and symptom burden (a collection of two or more symptoms). Key secondary outcomes were pain, depression, satisfaction with care, achieving preferred place of death, mortality/survival, unpaid caregiver burden, and cost‐effectiveness. Qualitative data was analysed where available.Main resultsWe identified 42 RCTs involving 7779 participants (6678 patients and 1101 caregivers/family members). Twenty‐one studies were with cancer populations, 14 were with non‐cancer populations (of which six were with heart failure patients), and seven with mixed cancer and non‐cancer populations (mixed diagnoses).HSPC was offered in different ways and included the following models: ward‐based, inpatient consult, outpatient, hospital‐at‐home or hospital outreach, and service provision across multiple settings which included hospital. For our main analyses, we pooled data from studies reporting adjusted endpoint values. Forty studies had a high risk of bias in at least one domain.Compared with usual care, HSPC improved patient HRQoL with a small effect size of 0.26 SMD over usual care (95% CI 0.15 to 0.37; I2 = 3%, 10 studies, 1344 participants, low‐quality evidence, higher scores indicate better patient HRQoL). HSPC also improved other person‐centred outcomes. It reduced patient symptom burden with a small effect size of ‐0.26 SMD over usual care (95% CI ‐0.41 to ‐0.12; I2 = 0%, 6 studies, 761 participants, very low‐quality evidence, lower scores indicate lower symptom burden). HSPC improved patient satisfaction with care with a small effect size of 0.36 SMD over usual care (95% CI 0.41 to 0.57; I2 = 0%, 2 studies, 337 participants, low‐quality evidence, higher scores indicate better patient satisfaction with care). Using home death as a proxy measure for achieving patient's preferred place of death, patients were more likely to die at home with HSPC compared to usual care (OR 1.63, 95% CI 1.23 to 2.16; I2 = 0%, 7 studies, 861 participants, low‐quality evidence). Data on pain (4 studies, 525 participants) showed no evidence of a difference between HSPC and usual care (SMD ‐0.16, 95% CI ‐0.33 to 0.01; I2 = 0%, very low‐quality evidence). Eight studies (N = 1252 participants) reported on adverse events and very low‐quality evidence did not demonstrate an effect of HSPC on serious harms. Two studies (170 participants) presented data on caregiver burden and both found no evidence of effect of HSPC (very low‐quality evidence). We included 13 economic studies (2103 participants). Overall, the evidence on cost‐effectiveness of HSPC compared to usual care was inconsistent among the four full economic studies. Other studies that used only partial economic analysis and those that presented more limited resource use and cost information also had inconsistent results (very low‐quality evidence).Quality of the evidenceThe quality of the evidence assessed using GRADE was very low to low, downgraded due to a high risk of bias, inconsistency and imprecision.Authors' conclusionsVery low‐ to low‐quality evidence suggests that when compared to usual care, HSPC may offer small benefits for several person‐centred outcomes including patient HRQoL, symptom burden and patient satisfaction with care, while also increasing the chances of patients dying in their preferred place (measured by home death). While we found no evidence that HSPC causes serious harms, the evidence was insufficient to draw strong conclusions. Although these are only small effect sizes, they may be clinically relevant at an advanced stage of disease with limited prognosis, and are person‐centred outcomes important to many patients and families. More well conducted studies are needed to study populations with non‐malignant diseases and mixed diagnoses, ward‐based models of HSPC, 24 hours access (out‐of‐hours care) as part of HSPC, pain, achieving patient preferred place of care, patient satisfaction with care, caregiver outcomes (satisfaction with care, burden, depression, anxiety, grief, quality of life), and cost‐effectiveness of HSPC. In addition, research is needed to provide validated person‐centred outcomes to be used across studies and populations

Structure of bacterial cytoplasmic chemoreceptor arrays and implications for chemotactic signaling

Most motile bacteria sense and respond to their environment through a transmembrane chemoreceptor array whose structure and function have been well-studied, but many species also contain an additional cluster of chemoreceptors in their cytoplasm. Although the cytoplasmic cluster is essential for normal chemotaxis in some organisms, its structure and function remain unknown. Here we use electron cryotomography to image the cytoplasmic chemoreceptor cluster in Rhodobacter sphaeroides and Vibrio cholerae. We show that just like transmembrane arrays, cytoplasmic clusters contain trimers-of-receptor-dimers organized in 12-nm hexagonal arrays. In contrast to transmembrane arrays, however, cytoplasmic clusters comprise two CheA/ CheW baseplates sandwiching two opposed receptor arrays. We further show that cytoplasmic fragments of normally transmembrane E. coli chemoreceptors form similar sandwiched structures in the presence of molecular crowding agents. Together these results suggest that the 12-nm hexagonal architecture is fundamentally important and that sandwiching and crowding can replace the stabilizing effect of the membrane