24 research outputs found

    High-sensitivity rod photoreceptor input to the blue-yellow color opponent pathway in macaque retina.

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    Small bistratified cells (SBCs) in the primate retina carry a major blue-yellow opponent signal to the brain. We found that SBCs also carry signals from rod photoreceptors, with the same sign as S cone input. SBCs exhibited robust responses under low scotopic conditions. Physiological and anatomical experiments indicated that this rod input arose from the AII amacrine cell-mediated rod pathway. Rod and cone signals were both present in SBCs at mesopic light levels. These findings have three implications. First, more retinal circuits may multiplex rod and cone signals than were previously thought to, efficiently exploiting the limited number of optic nerve fibers. Second, signals from AII amacrine cells may diverge to most or all of the approximately 20 retinal ganglion cell types in the peripheral primate retina. Third, rod input to SBCs may be the substrate for behavioral biases toward perception of blue at mesopic light levels

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Multiorgan MRI findings after hospitalisation with COVID-19 in the UK (C-MORE): a prospective, multicentre, observational cohort study

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    Introduction: The multiorgan impact of moderate to severe coronavirus infections in the post-acute phase is still poorly understood. We aimed to evaluate the excess burden of multiorgan abnormalities after hospitalisation with COVID-19, evaluate their determinants, and explore associations with patient-related outcome measures. Methods: In a prospective, UK-wide, multicentre MRI follow-up study (C-MORE), adults (aged ≥18 years) discharged from hospital following COVID-19 who were included in Tier 2 of the Post-hospitalisation COVID-19 study (PHOSP-COVID) and contemporary controls with no evidence of previous COVID-19 (SARS-CoV-2 nucleocapsid antibody negative) underwent multiorgan MRI (lungs, heart, brain, liver, and kidneys) with quantitative and qualitative assessment of images and clinical adjudication when relevant. Individuals with end-stage renal failure or contraindications to MRI were excluded. Participants also underwent detailed recording of symptoms, and physiological and biochemical tests. The primary outcome was the excess burden of multiorgan abnormalities (two or more organs) relative to controls, with further adjustments for potential confounders. The C-MORE study is ongoing and is registered with ClinicalTrials.gov, NCT04510025. Findings: Of 2710 participants in Tier 2 of PHOSP-COVID, 531 were recruited across 13 UK-wide C-MORE sites. After exclusions, 259 C-MORE patients (mean age 57 years [SD 12]; 158 [61%] male and 101 [39%] female) who were discharged from hospital with PCR-confirmed or clinically diagnosed COVID-19 between March 1, 2020, and Nov 1, 2021, and 52 non-COVID-19 controls from the community (mean age 49 years [SD 14]; 30 [58%] male and 22 [42%] female) were included in the analysis. Patients were assessed at a median of 5·0 months (IQR 4·2–6·3) after hospital discharge. Compared with non-COVID-19 controls, patients were older, living with more obesity, and had more comorbidities. Multiorgan abnormalities on MRI were more frequent in patients than in controls (157 [61%] of 259 vs 14 [27%] of 52; p<0·0001) and independently associated with COVID-19 status (odds ratio [OR] 2·9 [95% CI 1·5–5·8]; padjusted=0·0023) after adjusting for relevant confounders. Compared with controls, patients were more likely to have MRI evidence of lung abnormalities (p=0·0001; parenchymal abnormalities), brain abnormalities (p<0·0001; more white matter hyperintensities and regional brain volume reduction), and kidney abnormalities (p=0·014; lower medullary T1 and loss of corticomedullary differentiation), whereas cardiac and liver MRI abnormalities were similar between patients and controls. Patients with multiorgan abnormalities were older (difference in mean age 7 years [95% CI 4–10]; mean age of 59·8 years [SD 11·7] with multiorgan abnormalities vs mean age of 52·8 years [11·9] without multiorgan abnormalities; p<0·0001), more likely to have three or more comorbidities (OR 2·47 [1·32–4·82]; padjusted=0·0059), and more likely to have a more severe acute infection (acute CRP >5mg/L, OR 3·55 [1·23–11·88]; padjusted=0·025) than those without multiorgan abnormalities. Presence of lung MRI abnormalities was associated with a two-fold higher risk of chest tightness, and multiorgan MRI abnormalities were associated with severe and very severe persistent physical and mental health impairment (PHOSP-COVID symptom clusters) after hospitalisation. Interpretation: After hospitalisation for COVID-19, people are at risk of multiorgan abnormalities in the medium term. Our findings emphasise the need for proactive multidisciplinary care pathways, with the potential for imaging to guide surveillance frequency and therapeutic stratification

    Cambodia: From Phnom Penh to Siem Reap: A remarkable adventure in Southeast Asia - A short-term faculty-led service-learning program designed for Northfield Mount Hermon School

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    The CLC program design, Cambodia: From Phnom Penh to Siem Reap, A remarkable adventure in Southeast Asia: A short-term faculty-led service-learning program, is a two-week study abroad program that is being developed for Northfield Mount Hermon School (NMH). NMH is an independent co-educational college preparatory school in Northfield, Massachusetts. The current student population for the 2009-2010 school year is 650. Roughly 25% of the total student population is international students who come from thirty-one countries (NMH, 2009). The Cambodia study abroad program is aimed to enrich NMH students’ lives through cultural learning, service-learning, and intercultural communication (ICC). NMH will partner with Protect the Earth, Protect Yourself (PEPY), a Non-Government Organization (NGO) based in Siem Reap, Cambodia. PEPY started in 2005 as an educational organization that operated bike tours throughout Cambodia. Soon after its founding, PEPY evolved from a bike tours operation into providing educational, service-learning opportunities for high school students. PEPY (2009), states: Protect the Earth, Protect Yourself, is a belief rooted in the environmental education lessons of the first “PEPY Ride” trip. If you “Protect the Earth,” in effect, you also “Protect Yourself.” Our programs have expanded beyond environmental education with a focus now on Khmer literacy and broader improvements in the quality of education offered in government schools in rural Cambodia. Our basic ethos, however, is still the same: by making small changes in our lives and continually striving to educate ourselves about the problems around us, we can all take leadership roles in improving our own lives and then the world. The Cambodia program will target NMH students from freshman to seniors. The selected students will spend two-weeks studying basic Khmer, Cambodian history, and visiting historical and cultural sites. There will be a five-day Mekong River homestay where students will reside in a local island community and participate in community based service projects. Some of these service-learning projects might include: building biodigesters, enhancing fish ponds, rainwater collection, gardening, and road building. They will have an opportunity to visit a local music program, view fresh-water dolphins indigenous to the Mekong River, and tour Angkor Wat and other temples in Siem Reap. Students will also explore the Killing Fields to learn about the genocide imposed by the Khmer Rouge. The curriculum for NMH’s Cambodia program will include ideas from several ICC theorists including John Condon and Geertz Hofestede. Learning will be facilitated through the use David Kolb’s experiential learning model. Students will process and reflect on their experiences through journaling, discussion groups, and self-exploration. NMH faculty leaders and PEPY staff will deliver the program while in Cambodia
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