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Neuronal communication relies on the release of neurotransmitters from various populations of synaptic vesicles. Despite displaying vastly different release probabilities and mobilities, the reserve and recycling pool of vesicles co-exist within a single cluster suggesting that small synaptic biomolecular condensates could regulate their nanoscale distribution. Here, we performed a large-scale activity-dependent phosphoproteome analysis of hippocampal neurons in vitro and identified Tau as a highly phosphorylated and disordered candidate protein. Single-molecule super-resolution microscopy revealed that Tau undergoes liquid-liquid phase separation to generate presynaptic nanoclusters whose density and number are regulated by activity. This activity-dependent diffusion process allows Tau to translocate into the presynapse where it forms biomolecular condensates, to selectively control the mobility of recycling vesicles. Tau, therefore, forms presynaptic nano-biomolecular condensates that regulate the nanoscale organization of synaptic vesicles in an activity-dependent manner. Using single-molecule super-resolution microscopy, researchers revealed that Tau controls the recycling pool of synaptic vesicles in hippocampal neurons by forming nanoscale biomolecular condensates that are dynamically regulated by neuronal activity. [ABSTRACT FROM AUTHOR]

The blood-brain barrier (BBB) is a tightly and actively regulated vascular barrier. Answering fundamental biological and translational questions about the BBB with currently available approaches is hampered by a trade-off between accessibility and biological validity. We report an approach combining micropipette-based local perfusion of capillaries in acute brain slices with multiphoton microscopy. Micro-perfusion offers control over the luminal solution and allows application of molecules and drug delivery systems, whereas the bath solution defines the extracellular milieu in the brain parenchyma. Here we show, that this combination allows monitoring of BBB transport at the cellular level, visualization of BBB permeation of cells and molecules in real-time and resolves subcellular details of the neurovascular unit. In combination with electrophysiology, it permits comparison of drug effects on neuronal activity following luminal versus parenchymal application. We further apply micro-perfusion to the human and mouse BBB of epileptic hippocampi highlighting its utility for translational research and analysis of therapeutic strategies.The blood-brain barrier (BBB) tightly and dynamically regulates exchange with the brain. Here, the authors report a brain slice approach to study the native BBB in a highly controlled manner by combining intravascular perfusion and multiphoton microscopy. [ABSTRACT FROM AUTHOR]

The Delta (B.1.617.2) variant was the predominant UK circulating SARS-CoV-2 strain between May and December 2021. How Delta infection compares with previous variants is unknown. This prospective observational cohort study assessed symptomatic adults participating in the app-based COVID Symptom Study who tested positive for SARS-CoV-2 from May 26 to July 1, 2021 (Delta overwhelmingly the predominant circulating UK variant), compared (1:1, age- and sex-matched) with individuals presenting from December 28, 2020 to May 6, 2021 (Alpha (B.1.1.7) the predominant variant). We assessed illness (symptoms, duration, presentation to hospital) during Alpha- and Delta-predominant timeframes; and transmission, reinfection, and vaccine effectiveness during the Delta-predominant period. 3581 individuals (aged 18 to 100 years) from each timeframe were assessed. The seven most frequent symptoms were common to both variants. Within the first 28 days of illness, some symptoms were more common with Delta versus Alpha infection (including fever, sore throat, and headache) and some vice versa (dyspnoea). Symptom burden in the first week was higher with Delta versus Alpha infection; however, the odds of any given symptom lasting ≥ 7 days was either lower or unchanged. Illness duration ≥ 28 days was lower with Delta versus Alpha infection, though unchanged in unvaccinated individuals. Hospitalisation for COVID-19 was unchanged. The Delta variant appeared more (1.49) transmissible than Alpha. Re-infections were low in all UK regions. Vaccination markedly reduced the risk of Delta infection (by 69-84%). We conclude that COVID-19 from Delta or Alpha infections is similar. The Delta variant is more transmissible than Alpha; however, current vaccines showed good efficacy against disease. This research framework can be useful for future comparisons with new emerging variants. [ABSTRACT FROM AUTHOR]

Objective: This study examined the impact of Pathway Home™ (PH) transition services for high utilizers of psychiatric hospitalization on inpatient days and outpatient engagement post-hospital discharge. Methods: This case series study of forty PH graduates (5/22/2015–8/31/2018) used Medicaid claims to assess psychiatric inpatient days-per-month, average proportion of months with psychiatric emergency room, outpatient, and health home care management services. T-tests compared three time periods: the year prior, during, and after enrollment. Results: Graduates had significantly fewer psychiatric inpatient days/month during (M = 1.84, p < 0.001) and after PH enrollment (M = 1.88, p < 0.001) compared to prior to enrollment (M = 7.1), while emergency services were stable. Outpatient visits increased from 45% prior to 76% during enrollment (p < 0.001) and was sustained on follow-up (67%, p = 0.008). A similar pattern emerged for health home services (32%, 60%, and 50%). Conclusion: PH is a promising approach for improving outcomes for high utilizers of psychiatric inpatient services, with sustained impact on follow-up. [ABSTRACT FROM AUTHOR]

Worldwide, racial and ethnic minorities have been disproportionately impacted by COVID-19 with increased risk of infection, its related complications, and death. In the initial phase of population-based vaccination in the United States (U.S.) and United Kingdom (U.K.), vaccine hesitancy may result in differences in uptake. We performed a cohort study among U.S. and U.K. participants who volunteered to take part in the smartphone-based COVID Symptom Study (March 2020-February 2021) and used logistic regression to estimate odds ratios of vaccine hesitancy and uptake. In the U.S. (n = 87,388), compared to white participants, vaccine hesitancy was greater for Black and Hispanic participants and those reporting more than one or other race. In the U.K. (n = 1,254,294), racial and ethnic minority participants showed similar levels of vaccine hesitancy to the U.S. However, associations between participant race and ethnicity and levels of vaccine uptake were observed to be different in the U.S. and the U.K. studies. Among U.S. participants, vaccine uptake was significantly lower among Black participants, which persisted among participants that self-reported being vaccine-willing. In contrast, statistically significant racial and ethnic disparities in vaccine uptake were not observed in the U.K sample. In this study of self-reported vaccine hesitancy and uptake, lower levels of vaccine uptake in Black participants in the U.S. during the initial vaccine rollout may be attributable to both hesitancy and disparities in access. The authors show differences in self-reported vaccine hesitancy and uptake among participants from different racial and ethnic groups in the United States and in the United Kingdom during the initial phase of the COVID-19 vaccine rollout. [ABSTRACT FROM AUTHOR]

The Covid Symptom Study, a smartphone-based surveillance study on COVID-19 symptoms in the population, is an exemplar of big data citizen science. As of May 23rd, 2021, over 5 million participants have collectively logged over 360 million self-assessment reports since its introduction in March 2020. The success of the Covid Symptom Study creates significant technical challenges around effective data curation. The primary issue is scale. The size of the dataset means that it can no longer be readily processed using standard Python-based data analytics software such as Pandas on commodity hardware. Alternative technologies exist but carry a higher technical complexity and are less accessible to many researchers. We present ExeTera, a Python-based open source software package designed to provide Pandas-like data analytics on datasets that approach terabyte scales. We present its design and capabilities, and show how it is a critical component of a data curation pipeline that enables reproducible research across an international research group for the Covid Symptom Study. [ABSTRACT FROM AUTHOR]

Cyclocystoids are a poorly known, rare, extinct class of bi-facially flattened, disc shaped echinoderms, ranging from the Middle Ordovician to the Early Carboniferous. Articulated cyclocystoids are relatively common in the Ordovician but are rarer in younger strata. Here we describe Perforocycloides nathaliae new genus and species, from the early Silurian of Anticosti Island, Québec, Canada, the first articulated cyclocystoid from the Silurian of North America. This taxon is distinguished from other cyclocystoids by the number of variably sized marginal ossicles, the lack of interseptal plates, and the novelty of pores located in the distal part of the sutures between adjacent marginals on the dorsal surface. These dorsal intermarginal sutural pores led to canals which penetrated the contiguous area of the lateral surface of the marginals and emerged on the ventral surface between the cupules of adjacent marginals. These dorsal intermarginal sutural pores/canals appear to be unique to Perforocycloides and whilst their function is speculative, they provided some form of communication between the dorsal disc and the distal side of the ventral marginals/cupules. Perforocycloides most closely resembles the Ordovician–Silurian genus Zygocycloides, suggesting that this genus may have diversified more widely during the Silurian than previously reported. A review of global Silurian cyclocystoid distribution suggests taxa were geographically confined and that greatest diversity appears to have been located within Baltica. However, it also demonstrates our current limited knowledge. No specimens have been recorded from Gondwana (e.g. Africa, Australia, South America), Siberia, and North and South China, nor are any specimens known confidently anywhere from Přidolí strata. [ABSTRACT FROM AUTHOR]

These authors contributed equally: Long H. Nguyen, Amit D. Joshi, David A. Drew. The original version of this Article contained an error in Table 1. [Extracted from the article]

Antisense oligonucleotides and small interfering RNAs, which suppress the translation of specific mRNA target proteins, are emerging as important therapeutic modalities for the treatment of cardiovascular disease. Over the last 25 years, the advances in all aspects of antisense technology, as well as a detailed understanding of the mechanism of action of antisense drugs, have enabled their use as therapeutic agents. These advancements culminated in the FDA approval of the first chronically administered cardiovascular antisense therapeutic, mipomersen, which targets hepatic apolipoprotein B mRNA. This review provides a brief history of antisense technology, highlights the progression of mipomersen from preclinical studies to multiple Phase III registration trials, and gives an update on the status of other cardiovascular antisense therapeutics currently in the clinic. [ABSTRACT FROM AUTHOR]

Fatty liver disease is associated with obesity and type 2 diabetes, and hepatic lipid accumulation may contribute to insulin resistance. Histone deacetylase 3 (Hdac3) controls the circadian rhythm of hepatic lipogenesis. Here we show that, despite severe hepatosteatosis, mice with liver-specific depletion of Hdac3 have higher insulin sensitivity without any changes in insulin signaling or body weight compared to wild-type mice. Hdac3 depletion reroutes metabolic precursors towards lipid synthesis and storage within lipid droplets and away from hepatic glucose production. Perilipin 2, which coats lipid droplets, is markedly induced upon Hdac3 depletion and contributes to the development of both steatosis and improved tolerance to glucose. These findings suggest that the sequestration of hepatic lipids in perilipin 2-coated droplets ameliorates insulin resistance and establish Hdac3 as a pivotal epigenomic modifier that integrates signals from the circadian clock in the regulation of hepatic intermediary metabolism. [ABSTRACT FROM AUTHOR]

Fenretinide and tamoxifen have additive antitumor effects preclinically. We performed a randomized, placebo-controlled, double-blind adjuvant trial in breast cancer patients treated for 5 years with tamoxifen, with or without fenretinide. Between October 1995 and October 1999, 426 postmenopausal women with hormone receptor-positive breast cancer were randomized. Patients were monitored for efficacy and toxicity. Four hundred and nineteen patients were evaluable. The study was terminated early due to slow accrual. There were no significant differences between treatment groups in DFS, TTR or survival. More patients stopped treatment early on the fenretinide arm than on placebo (P = 0.02). Grade 3/4 toxicities, including visual problems and musculoskeletal complaints were more common in patients receiving fenretinide (P = 0.007). A Night Blindness Questionnaire was used to monitor nyctalopia, which was slightly, but not significantly, more common on fenretinide. In this underpowered study, no significant difference was observed in efficacy between treatment groups. This trial provides important toxicity information about fenretinide, a retinoid that has been used in the prevention setting, because it is the only placebo-controlled, double-blind randomized study ever performed. [ABSTRACT FROM AUTHOR]

The quality and interpretability of the paleobiological record depends on the preservation of morphological and geochemical fossils. Siliceous microfossils and sedimentary pigments are often cornerstones in paleoecology, although the microbial and geochemical processes conducive to their preservation remain poorly constrained. We examined sediments from an alpine lake in Banff National Park (Alberta, Canada) where diatom frustules are completely dissolved within 50 years of deposition. Diatom dissolution, silica recycling, and diagenetic alteration of algal pigments were investigated, in conjunction with porewater geochemistry and microelectrode profiling of the sediment–water interface. Analysis of sediment trap material showed ~90% of biogenic silica (BSi) production is lost prior to burial. Silica flux calculations, based on dissolved silica (as H4SiO4) in pore-waters, show a further ~6% of total BSi is returned to the water column from the upper 4 cm of sediments, implying that only ~4% of total BSi is permanently archived in sediments. In situ sediment pH and O2 profiles reveal that aerobic respiration by bacteria fully consumes oxygen by a depth of 4 mm into the sediment, with associated strong pH and redox gradients. During sedimentation and early diagenesis, diatoms undergo loss of extracellular polymeric substances that coat their frustules, promoting silica dissolution and leading to the loss of the microfossil record by a depth of 3.25 cm. Sedimentary pigments similarly undergo rapid degradation, but diatom-related carotenoids persist below the depth of silica dissolution. This work provides new insights on diagenetic processes in lakes, with broad implications for the interpretation of sedimentary proxies for algal production. [ABSTRACT FROM AUTHOR]

Evidence-based practice (EBP) requires practitioners to identify and formulate questions in response to patient encounters, and to seek, select, and appraise applicable clinical research. A standardized workshop format serves as the model for training of medical educators in these skills. We developed an evaluation exercise to assess the ability to identify and solve a problem requiring the use of targeted skills and administered it to 47 North American junior faculty and residents in various specialties at the close of two short workshops in EBP. Prior to the workshop, subjects reported prior training in EBP and completed a previously validated knowledge test. Our post-workshop exercise differed from the baseline measures and required participants to spontaneously identify a suitable question in response to a simulated clinical encounter, followed by a description of a stepwise approach to answering it. They then responded to successively more explicitly prompted queries relevant to their question. We analyzed responses to identify areas of skill deficiency and potential reasons for these deficiencies. Twelve respondents (26%) initially failed to identify a suitable question in response to the clinical scenario. Ability to choose a suitable question correlated with the ability to connect an original question to an appropriate study design. Prior EBP training correlated with the pretest score but not with performance on our exercise. Overall performance correlated with ability to correctly classify their questions as pertaining to therapy, diagnosis, prognosis, or harm. We conclude that faculty and residents completing standard workshops in EBP may still lack the ability to initiate and investigate original clinical inquiries using EBP skills. [ABSTRACT FROM AUTHOR]

People with mental illness around the world continue to suffer from stigmatization and limited care. Previous studies utilizing self-report questionnaires indicate that many medical students regard clinical work with psychiatric patients as unappealing, while the professionalism literature has documented a general decline in students’ capacity for empathy over the course of medical school. Through in-depth interviews, this study attempts to better understand the formation of medical students’ perceptions of psychiatry and the implications of that process for a more general understanding of the impact of emotionally-laden experiences on medical students’ capacity for empathy. Forty-seven fourth-year medical students who had expressed interest or performed well in psychiatry were asked a series of questions to elicit their perceptions of the field of psychiatry. Interview transcripts were systematically coded using content analysis and principles of grounded theory. Stigma, stereotypes, and stressfully intense emotional reactions seemed to adversely affect the students’ expected satisfaction from and willingness to care for the mentally ill, despite enjoying psychiatry’s intellectual content and the opportunity to develop in-depth relationships with patients. Teaching faculty need to directly address the stigma and stereotypes that surround mental illness and actively help medical students cope with the stress that they report experiencing during their psychiatry clerkship in order to improve the recognition and treatment of psychiatric illness by newly graduating physicians. More generally, the relationships that we identify among stress, stigmatization, and stereotyping along an empathic spectrum suggest that increased attention should be paid to the stress that empathy can entail. This perspective may allow for the creation of similarly targeted interventions throughout the medical school curriculum to counteract the decline in empathy, the so-called “hardening of the heart,” associated with physician-training worldwide. [ABSTRACT FROM AUTHOR]

In many parts of the world the practice of medicine and medical education increasingly focus on providing patient care within context of the larger healthcare system. Our purpose is to solicit perceptions of all professional stakeholders (e.g. nurses) of the system regarding the U.S. ACGME competency Systems Based Practice to uncover the extent to which there is agreement or discrepancy among key system stakeholders. Eighty-eight multidisciplinary personnel (n = 88) from two academic medical centers were invited to participate in one of 14 nominal group process sessions. Participants generated and prioritized resident characteristics that they believed were important for effective System Based Practices. Through content analysis the prioritized attribute statements were coded to identify embedded themes of resident roles and behavior. From the themes, three major resident roles emerged: resident as Self-Manager, Team Collaborator, and Patient Advocate. No one professional group (e.g., nurses, attending physicians, social workers) emphasized all of these roles. Some concepts that are emphasized in the ACGME definition like using cost–benefit analysis were conspicuously absent from the healthcare team generated list. We showed that there are gaps between the key stakeholders prioritizations about the ACGME definition of SBP and, more generally, the behaviors and roles identified by healthcare team stakeholders beyond the U.S. This suggests that within the process of developing a comprehensive working understanding of the Systems Based Practice competency (or other similar competencies, such as in CanMEDS), it is necessary to use multiple stakeholders in the system (perhaps including patients) to more accurately identify key resident roles and observable behaviors. [ABSTRACT FROM AUTHOR]

Early residency is a crucial time in the professional development of physicians. As interns assume primary care for their patients, they take on new responsibilities. The events they find memorable during this time could provide us with insight into their developing professional identities. To evaluate the most critical events in the lives of interns. Forty-one internal medicine residents at one program participated in a two-day retreat in the fall of their first year. Each resident provided a written description of a recent high point, low point, and patient conflict. We used a variant of grounded theory to analyze these critical incidents and determine the underlying themes of early internship. Independent inter-rater agreement of >90% was achieved for the coding of excerpts. The 123 critical incidents were clustered into 23 categories. The categories were further organized into six themes: confidence, life balance, connections, emotional responses, managing expectations, and facilitating teamwork. High points were primarily in the themes of confidence and connections. Low points were dispersed more generally throughout the conceptual framework. Conflicts with patients were about negotiating the expectations inherent in the physician–patient relationship. The high points, low points, and conflicts reported by early residents provide us with a glimpse into the lives of interns. The themes we have identified reflect critical challenges interns face the development of their professional identity. Program directors could use this process and conceptual framework to guide the development and promotion of residents’ emerging professional identities. [ABSTRACT FROM AUTHOR]

Selecting a pharmacologically relevant animal species for testing the safety and toxicity of novel monoclonal antibody (mAb) therapies to support clinical testing can be challenging. Frequently, the species of choice is the primate. With the increased number of mAbs in the pharmaceutical pipeline, this has significant implications for primate use, and so raises several important scientific, ethical and economic issues. Here, following a recent international workshop held to debate this topic, we discuss issues in the preclinical testing of mAbs, with a particular focus on species relevance and primate use, and provide suggestions for how these issues might be addressed. [ABSTRACT FROM AUTHOR]

Dynamin I is dephosphorylated at Ser-774 and Ser-778 during synaptic vesicle endocytosis (SVE) in nerve terminals. Phosphorylation was proposed to regulate the assembly of an endocytic protein complex with amphiphysin or endophilin. Instead, we found it recruits syndapin I for SVE and does not control amphiphysin or endophilin binding in rat synaptosomes. After depolarization, syndapin showed a calcineurin-mediated interaction with dynamin. A peptide mimicking the phosphorylation sites disrupted the dynamin-syndapin complex, not the dynamin-endophilin complex, arrested SVE and produced glutamate release fatigue after repetitive stimulation. Pseudophosphorylation of Ser-774 or Ser-778 inhibited syndapin binding without affecting amphiphysin recruitment. Site mutagenesis to alanine arrested SVE in cultured neurons. The effects of the sites were additive for syndapin I binding and SVE. Thus syndapin I is a central component of the endocytic protein complex for SVE via stimulus-dependent recruitment to dynamin I and has a key role in synaptic transmission. [ABSTRACT FROM AUTHOR]

The prognostic significance of micrometastasis after neoadjuvant chemotherapy for locally advanced breast cancer is unknown. We examined the residual lymph node metastasis size in patients after treatment with neoadjuvant chemotherapy to determine the relevance of metastasis size on outcome. Stage II/III breast cancer patients treated with neoadjuvant chemotherapy at our institution from 1991 to 2002 were included. We examined the relationship of postneoadjuvant chemotherapy lymph node metastasis size and number with distant disease-free survival (DDFS) and overall survival (OS). In 122 patients with a median follow-up of 5.4 years, we found not only that patients with an increasing number of residual positive nodes had progressively worse DDFS and OS ( P < .0001 for both) compared with patients with negative nodes, but also that the size of the largest lymph node metastasis was associated with worse DDFS and OS ( P < .0001 for both) in both univariate and multivariate analysis. Compared with negative nodes, even lymph node micrometastasis (<2 mm) was associated with worsened DDFS and OS (adjusted P = .02 and P = .005, respectively). Residual micrometastatic disease in the axillary lymph nodes after neoadjuvant chemotherapy is predictive of worse prognosis than negative nodes. In this study, the lymph node metastasis size and the number of involved lymph nodes were independent powerful predictors of DDFS and OS. [ABSTRACT FROM AUTHOR]

Selenium has been found at elevated concentrations in water, sediments, and aquatic biota in the Elk River (British Columbia, Canada) and some of its tributaries downstream of several coal mines. Selenium water concentrations in those areas exceed Canadian and British Columbia guidelines and are above levels at which adverse effects to fish and waterfowl could occur. We compared selenium concentrations in the eggs of two riverine waterbirds, American dippers and spotted sandpipers, with measures of productivity: the number of eggs laid, egg hatchability, and nestling survival. In American dippers, the mean egg selenium concentration from the exposed areas, 1.10 ± SE 0.059 μg/g wet weight, was indistinguishable from the reference areas, 0.96 ± SE 0.059 μg/g wet weight. For spotted sandpipers, the mean egg selenium concentration in the exposed areas, 2.2 ± 0.5 μg/g wet weight, was significantly higher than in the reference areas, 1.2 ± 0.14 μg/g wet weight, but less than reported thresholds tor waterfowl and other shorebirds. There were no significant differences in egg hatchability between dippers in reference and exposed areas, but reduced hatchability was apparent for sandpipers in exposed locations. Despite the slightly reduced hatchability in sandpipers, overall productivity was higher than regional norms for both species; thus, selenium did not affect the number of young recruited to local populations. We did not observe teratogenic effects in either species, although none was expected at these concentrations. Despite moderately high selenium concentrations in the water, mean egg selenium concentrations were less than predicted from uptake models. We hypothesise that the relatively low uptake of selenium into the eggs of the two waterbirds in this study is likely due to their Iotic environment's low biological transformation and uptake rates. [ABSTRACT FROM AUTHOR]

Purpose. Immunotherapy using either dendritic cells (DCs) or expanded cytotoxic T cells (CTLs) has received increased interest in the treatment of specific malignancies including metastatic breast cancer (MBC). DCs can be generated ex vivo from monocytes or CD34+ precursors. The ability to expand and safely administer CD34-derived DCs in patients with MBC that have received prior cytotoxic chemotherapy has not been evaluated. Methods. We enrolled ten patients with MBC that had received prior chemotherapy for the treatment of metastatic disease on a phase I/II trial designed to test the safety and feasibility of administering ex vivo expanded DCs from CD34+ progenitor cells. Results. Using a cocktail of multiple different cytokines, we could expand DCs 19-fold compared to the initial CD34-selected product, which allowed the administration of as many as six vaccine treatments per patient. Patients received three to six injections i.v. of DCs pulsed with either the wild type GP2 epitope from the HER-2/neu protein or an altered peptide ligand, isoleucine to leucine (I2L). Toxicity was mild, with no patients demonstrating grade III toxicity during the treatment. Two patients with subcutaneous disease had a partial response to therapy, while IFN-γ-producing CD8+ T cells could be found in two other patients during treatment. Conclusions. This approach is safe and effective in generating a significant quantity of DCs from CD34-precursors. [ABSTRACT FROM AUTHOR]

Synaptic vesicle endocytosis (SVE) is triggered by calcineurin-mediated dephosphorylation of the dephosphin proteins. SVE is maintained by the subsequent rephosphorylation of the dephosphins by unidentified protein kinases. Here, we show that cyclin-dependent kinase 5 (Cdk5) phosphorylates dynamin I on Ser 774 and Ser 778 in vitro, which are identical to its endogenous phosphorylation sitesin vivo. Cdk5 antagonists and expression of dominant-negative Cdk5 block phosphorylation of dynamin I, but not of amphiphysin or AP180, in nerve terminals and inhibit SVE. Thus Cdk5 has an essential role in SVE and is the first dephosphin kinase identified in nerve terminals. [ABSTRACT FROM AUTHOR]

Presents a study that determined the influence of spatial and temporal scale of acidification on the resilience of epilithic assemblages during chemical recovery of Canadian boreal lakes. Effects of anthropogenic acidification of boreal lakes on several environmental variables; Indicators of recovery in acidifed lakes; Comparison of experimental and atmospheric acidification of lakes; Details of study lakes and sampling protocols.

The identification of genomic rearrangements involving more than 0.5 kb of the BRCA1 gene has confirmed a more complex mutation spectrum than was initially appreciated. Genomic rearrangements in BRCA1 represent 15% of all mutations in a group of French and American breast and ovarian cancer families and 36% of all mutations in a group of Dutch families. The rearrangements described to date range in size from 510 bp to 23.8 kb, are found throughout the gene, and are most frequently attributable to homologous recombination. We describe the identification of rearrangements in two breast and ovarian cancer families that involve 3.4 and 11.5 kb of the BRCA1 gene and span multiple exons but maintain the reading frame. Both gene rearrangements appear to result from Alu-mediated homologous recombination and have been detected by using a combination of protein truncation analysis and Southern blot analysis. These rearrangements result in the loss of amino acids that lie at the carboxy-terminus of the protein and that have previously been shown to have functional significance. Because these rearrangements result in the deletion of exons but maintain the reading frame, they may provide insights into specific regions and amino acids that have functional significance for the BRCA1 protein. [ABSTRACT FROM AUTHOR]

The viscosities of blood from shorthorn sculpin ( Myoxocephalus scorpius), longhorn sculpin ( Myoxocephalus octodecemspinosus) and winter flounder ( Pseudopleuronectes americanus) were compared using a cone-plate viscometer. Both species of sculpin were almost identical with respect to blood and plasma viscosity at the temperatures (0 and 15°C) and shear rates (2.3-90/s) examined. In contrast, the viscosities of winter flounder blood and plasma were considerably greater than those observed in the sculpins. This difference in blood viscosity between the shorthorn sculpin and the winter flounder persisted over the hematocrit range of 0 to 40% red blood cells. The viscosity of the plasma and the interactions between plasma proteins and red blood cells appeared to be the major reasons for the relatively high viscosity of the flounder blood. Although a proportion of the flounder blood viscosity was attributable to fibrinogen, other plasma proteins also appeared to play a significant role. The relatively low blood viscosity of the sculpin species may confer a circulatory advantage during periods of low water temperatures. [ABSTRACT FROM AUTHOR]

Oxygen consumption (VO) of juvenile Arctic cod ( Boreogadus saida) was investigated at low tempera tures (six temperatures; range -0.5 to 2.7°C). Small (mean wt. 6-8 g) and large (mean wt. 14 g) fish were acclimated, or adjusted to a constant temperature (0.4°C), for 5 months and then tested for metabolic cold adaptation (elevated metabolic rates in polar fishes). Short-term (2 weeks) acclimated fish showed elevated VO similar to previously established values for polar fishes, but there was no such evidence after longterm acclimation. Long-term acclimation caused VO values to drop significantly (from 86.0 to 46.5 mg O·kg·h, at 0.4°C), which showed that metabolic cold adaptation was a phenomenon caused by insufficien: acclimation time for fish in respiration experiments. We also measured the effects of temperature and feeding on VO. A temperature increase of 2.3°C resulted in relatively large increases in VO for both longand short-term acclimated fish (Q = 6.7 and 7.1, respectively), which suggests that metabolic processes are strongly influenced by temperature when it is close to zero. Feeding individuals to satiation caused significant increases in VO above pre-fed values (34-60% within 1-2 days after feeding). Respiration budgets of starved and fed Arctic cod at ambient temperatures in Resolute Bay N.W.T., Canada, were used to model annual respiration costs and potential weight loss. Low respiration costs for Arctic cod at ambient temperatures result in high growth efficiency during periods of feeding and low weight loss during periods of starvation. [ABSTRACT FROM AUTHOR]

Normal human melanocytes require 12- O-tetradecanoylphorbol 13-acetate (TPA) for prolonged growth in vitro. In contrast, the growth of human malignant melanoma cells is often inhibited by TPA. In this study, we have confirmed and extended these observations. Since protein kinase C (PKC) is an important mediator of the effects of TPA, we have investigated the nature of this differential growth response by examining PKC expression and activity in primary cultures of human neonatal melanocytes and metastatic melanoma cell strains. PKC, when measured by immunore-activity or a functional assay, was found to be more abundant in melanoma cells than in melanocytes. When specific isotypes were examined by Northern analysis, PKC-α and-ε were expressed in both melanocytes and melanoma. PKC-β was expressed in melanocytes, but was undetectable by Northern analysis in 10 out of 11 melanoma cell strains. Southern analysis revealed that no gross deletions or rearrangements of the PKC-β gene had occurred. These data suggest that down-regulation of the PKC-β gene occurs frequently during the process of transformation of melanocytes. Furthermore, differential expression of PKC isotypes may explain the different effects of TPA on melanocyte and melanoma cell growth. [ABSTRACT FROM AUTHOR]

Background: Evidence-based teaching, such as active learning, is associated with increases in student learning and engagement. Although many faculty are beginning to adopt innovative practices, traditional lecture-based teaching tends to dominate college science education. What are the factors associated with faculty's decision to incorporate evidence-based teaching? While there are known barriers that limit adoption of evidence-based practices in science classrooms (e.g., lack of time, student resistance), the present work reveals that instructors' perceptions of supports (e.g., access to teaching resources, encouragement from colleagues) shows a stronger relationship to instructors' use of evidence-based teaching. Results: These results come from a uniquely large dataset of college science faculty and instructors from across the USA (n = 584), who received training in evidence-based teaching. Multiple linear regression analyses of the relationship among perceived supports, barriers, and reported implementation of evidence-based practices showed that instructors report greater implementation when they perceive more social, personal, and resource supports even when barriers are also indicated as present. Conclusion: Faculty's perceived supports, not perceived barriers, are most strongly related to their reported implementation of evidence-based teaching. These findings suggest relevant stakeholders devote increased attention identifying and building the factors that promote evidence-based teaching in addition to reducing what inhibits it. [ABSTRACT FROM AUTHOR]