Angiotensin converting enzyme gene insertion/deletion polymorphism: Case‐control association studies in schizophrenia,major affective disorder,and tardive dyskinesia and a family‐based association study in schizophrenia

Angiotensin converting enzyme (ACE) is a candidate gene for psychiatric disorders. We examined the frequency of a functional insertion/deletion (I/D) polymorphism in the 16th intron of the ACE gene (located on chromosome 17q23) in groups of patients with schizophrenia (n = 104 and 113), major depression (n = 55), and bipolar disorder (n = 87) compared to healthy control subjects (n = 87). There was no evidence for allelic or genotypic association of the polymorphism with any of the disorders or with tardive dyskinesia (TD) in patients with schizophrenia. In a sample of nuclear families (n = 61) made up of one or more patients with schizophrenia recruited with their parents, there was no evidence for biased transmission of ACE I/D alleles. Particularly in the case of schizophrenia, these findings do not support an association of the ACE I/D polymorphism with the phenotypes examined. © 2002 Wiley‐Liss, Inc.     

Body composition affects the response to erythropoiesis-stimulating agents in patients with chronic kidney disease in dialysis

Background: The response to erythropoiesis-stimulating agents (ESA) in patients with chronic kidney disease (CKD) is variable. The body mass index (BMI) variations can modify the response to ESA. The objective was to assess the effect of body composition on the response to ESA in dialysis patients. Methods: This is an observational cross-sectional study. Prevalent hemodialysis and peritoneal dialysis (PD) patients were selected. In the same day, a single blood test, a body composition analysis using bioimpedance spectroscopy and anthropometric measurements were performed. We collected ESA doses. We analyzed erythropoietin resistance index (ERI). The ERI was calculated dividing the weekly weight-adjusted (kg) dose of ESA (IU) by the hemoglobin level (g/dL). Results: The study was comprised of 218 patients (58% men; age 65 (16) years old; 80% hemodialysis, 20% PD). There was an inverse correlation between ERI and BMI (p?=?0.01), fat tissue index (FTI) (p?=?0.01) and prealbumin (p?=?0.04). We found an independent association between higher ERI levels and lower FTI and prealbumin values. Conclusion: Response to ESA is influenced by body composition. Fat tissue favors the body’s response to ESA.     

Memory and navigation: Compression of space varies with route length and turns

For memory to be efficient and useful during recall, problem‐solving, and planning, retrieval must be compressed in time. Evidence from rodents suggests that neural compression during replay of spatial memories varies widely, with a range of compression ratios reported from 6:1 to 64:1. Anecdotal evidence suggests that similar compression occurs during mental navigation in humans: we recall how to get from one place to another countless times almost every day of our lives, and this recall never takes as long as physically travelling those routes would take. In this experiment we sought to determine whether this behavioural compression could be measured during mental navigation in humans (spatial memory replay), and which factors might affect the compression of such spatial memories. To this end, thirty participants mentally navigated routes between two landmarks, which varied in length and number of turns, as we measured replay times and recorded ratings of familiarity, detail, and presence. A multi‐level model was used to determine which factors were associated with variation in compression. Route length and number of turns emerged from this model as significantly correlated with compression, such that longer routes were more compressed while compression was attenuated as the number of turns in a route increased. This suggests that compression during recall may be affected by specific features of a route, especially those that may act to segment the space or event being represented. © 2015 Wiley Periodicals, Inc.     

From the Cover: Rocky Mountain subalpine forests now burning more than any time in recent millennia

The 2020 fire season punctuated a decades-long trend of increased fire activity across the western United States, nearly doubling the total area burned in the central Rocky Mountains since 1984. Understanding the causes and implications of such extreme fire seasons, particularly in subalpine forests that have historically burned infrequently, requires a long-term perspective not afforded by observational records. We place 21st century fire activity in subalpine forests in the context of climate and fire history spanning the past 2,000 y using a unique network of 20 paleofire records. Largely because of extensive burning in 2020, the 21st century fire rotation period is now 117 y, reflecting nearly double the average rate of burning over the past 2,000 y. More strikingly, contemporary rates of burning are now 22% higher than the maximum rate reconstructed over the past two millennia, during the early Medieval Climate Anomaly (MCA) (770 to 870 Common Era), when Northern Hemisphere temperatures were ∼0.3 °C above the 20th century average. The 2020 fire season thus exemplifies how extreme events are demarcating newly emerging fire regimes as climate warms. With 21st century temperatures now surpassing those during the MCA, fire activity in Rocky Mountain subalpine forests is exceeding the range of variability that shaped these ecosystems for millennia.

The 2020 fire season punctuated a trend of increasing wildfire activity throughout the 21st century across the western United States (“the West”). This trend is well-linked to increasingly fire-conducive climate conditions (1) and anthropogenic climate change (2), and it is coming with devastating human impacts (3).Across different ecosystems and regions of the West, the causes of increasing fire activity vary (4–6), and thus so too do potential management and policy solutions (7, 8). Over a century of policies have limited Indigenous fire stewardship and emphasized fire suppression, leading to significant fire deficits in low- and mid-elevation forests that historically burned frequently in low-intensity surface fires (9, 10). This differs from high-elevation subalpine forests, where fire history records show that large, stand-replacing fires typically burned once every one to several centuries over recent millennia (11–17). Continued 21st century warming in these high-elevation forests is predicted to increase fire activity beyond the historical range of variability (18, 19). Detecting if and when such changes emerge, however, and understanding the magnitude of ongoing change requires placing contemporary burning in the context of the past.Here, we use a unique network of paleofire records spanning the past 2,000 y to test the hypothesis that 21st century climate change has led to unprecedented fire activity in Rocky Mountain subalpine forests. These high-elevation forests are useful sentinels of climate change impacts because their typically cool, moist climate limits frequent fire, and they have historically experienced less land-use change and fire suppression than lower-elevation forests. To place late 20th and 21st century wildfire activity in a millennial-scale context, we draw on existing tree-ring and lake sediment records of fire history from subalpine forests in a ∼30,000 km² region in the central Rocky Mountains of Colorado and Wyoming (Fig. 1A), similar in size to the Greater Yellowstone Ecosystem.Open in a separate windowFig. 1.Wildfire and climate in the central Rocky Mountains. (A) Central Rocky Mountains (“Ecoregion”) and focal study area, with fire perimeters from 1984 to 2019 (thin, light red lines) and 2020 (thick, dark red lines; see also SI Appendix, Fig. S3). The 20 lakes with published paleofire records are shown with white circles; lakes recording fire events during the early MCA, c. 770 to 870 CE, are shown in red. The general locations of published tree-ring–based stand-age and fire-scar records used to reconstruct fire extent are shown with black plus symbols; the geographic extent represented by each study exceeds the extent of the symbols. (B) Ecoregion-wide area burned for fire perimeters displayed in A and average May to September VPD. Percentages above red bars are the proportion of total area burned (from 1984 to 2020) contributed by the given year.