Changes to Public Health Surveillance Methods Due to the COVID-19 Pandemic: Scoping Review.

BACKGROUND: Public health surveillance plays a vital role in informing public health decision-making. The onset of the COVID-19 pandemic in early 2020 caused a widespread shift in public health priorities. Global efforts focused on COVID-19 monitoring and contact tracing. Existing public health programs were interrupted due to physical distancing measures and reallocation of resources. The onset of the COVID-19 pandemic intersected with advancements in technologies that have the potential to support public health surveillance efforts. OBJECTIVE: This scoping review aims to explore emergent public health surveillance methods during the early COVID-19 pandemic to characterize the impact of the pandemic on surveillance methods. METHODS: A scoping search was conducted in multiple databases and by scanning key government and public health organization websites from March 2020 to January 2022. Published papers and gray literature that described the application of new or revised approaches to public health surveillance were included. Papers that discussed the implications of novel public health surveillance approaches from ethical, legal, security, and equity perspectives were also included. The surveillance subject, method, location, and setting were extracted from each paper to identify trends in surveillance practices. Two public health epidemiologists were invited to provide their perspectives as peer reviewers. RESULTS: Of the 14,238 unique papers, a total of 241 papers describing novel surveillance methods and changes to surveillance methods are included. Eighty papers were review papers and 161 were single studies. Overall, the literature heavily featured papers detailing surveillance of COVID-19 transmission (n=187). Surveillance of other infectious diseases was also described, including other pathogens (n=12). Other public health topics included vaccines (n=9), mental health (n=11), substance use (n=4), healthy nutrition (n=1), maternal and child health (n=3), antimicrobial resistance (n=2), and misinformation (n=6). The literature was dominated by applications of digital surveillance, for example, by using big data through mobility tracking and infodemiology (n=163). Wastewater surveillance was also heavily represented (n=48). Other papers described adaptations to programs or methods that existed prior to the COVID-19 pandemic (n=9). The scoping search also found 109 papers that discuss the ethical, legal, security, and equity implications of emerging surveillance methods. The peer reviewer public health epidemiologists noted that additional changes likely exist, beyond what has been reported and available for evidence syntheses. CONCLUSIONS: The COVID-19 pandemic accelerated advancements in surveillance and the adoption of new technologies, especially for digital and wastewater surveillance methods. Given the investments in these systems, further applications for public health surveillance are likely. The literature for surveillance methods was dominated by surveillance of infectious diseases, particularly COVID-19. A substantial amount of literature on the ethical, legal, security, and equity implications of these emerging surveillance methods also points to a need for cautious consideration of potential harm.

Implementing a Clinical Decision Support Tool to Improve Physical Activity.

BACKGROUND: Currently, only about half of U.S. adults achieve current physical activity guidelines. Routine physical activity is not regularly assessed, nor are patients routinely counseled by their healthcare provider on achieving recommended levels. The three-question physical activity vital sign (PAVS) was developed to assess physical activity duration and intensity and identify adults not meeting physical activity guidelines. Clinical decision support provided via a best practice advisory in an electronic health record (EHR) system can be triggered as a prompt, reminding healthcare providers to implement the best practice intervention when appropriate. Remote patient monitoring of physical activity can provide objective data in the EHR. OBJECTIVES: This study aimed to evaluate the feasibility and clinical utility of embedding the PAVS and a triggered best practice advisor into the EHR in an ambulatory preventive cardiology practice setting to alert providers to patients reporting low physical activity and prompt healthcare providers to counsel these patients as needed. METHODS: Three components based in the EHR were integrated for the purpose of this study: Patients completed the PAVS through their electronic patient portal prior to an office visit, a best practice advisory was created to prompt providers to counsel patients who reported low levels of physical activity, and remote patient monitoring via Fitbit synced to the EHR provided objective physical activity data. The intervention was pilot-tested in the Epic EHR for 1 year (July 1, 2021 to June 30, 2022). Qualitative feedback on the intervention from both providers and patients was obtained at the completion of the study. RESULTS: Monthly assessments of the use of the PAVS and best practice advisory and remote patient monitoring were completed. Patients' completion of the PAVS varied from 35% to 48% per month. The best practice advisory was signed by providers between 2% and 65% and was acknowledged by 2%-22% per month. The majority (58%) of patients were able to sync a Fitbit device to their EHR for remote monitoring. DISCUSSION: Although uptake of each component needs improvement, this pilot demonstrated the feasibility of incorporating a physical activity promotion intervention into the EHR. Qualitative feedback provided guidance for future implementation.

What are effective strategies to respond to the psychological impacts of working on the frontlines of a public health emergency?

Background: The COVID-19 pandemic has disrupted the healthcare and public health sectors. The impact of working on the frontlines as a healthcare or public health professional has been well documented. Healthcare organizations must support the psychological and mental health of those responding to future public health emergencies. Objective: This systematic review aims to identify effective interventions to support healthcare workers' mental health and wellbeing during and following a public health emergency. Methods: Eight scientific databases were searched from inception to 1 November 2022. Studies that described strategies to address the psychological impacts experienced by those responding to a public health emergency (i.e., a pandemic, epidemic, natural disaster, or mass casualty event) were eligible for inclusion. No limitations were placed based on study design, language, publication status, or publication date. Two reviewers independently screened studies, extracted data, and assessed methodological quality using the Joanna Briggs Institute critical appraisal tools. Discrepancies were resolved through discussion and a third reviewer when needed. Results were synthesized narratively due to the heterogeneity of populations and interventions. Outcomes were displayed graphically using harvest plots. Results: A total of 20,018 records were screened, with 36 unique studies included in the review, 15 randomized controlled trials, and 21 quasi-experimental studies. Results indicate that psychotherapy, psychoeducation, and mind-body interventions may reduce symptoms of anxiety, burnout, depression, and Post Traumatic Stress Disorder, with the lowest risk of bias found among psychotherapy interventions. Psychoeducation appears most promising to increase resilience, with mind-body interventions having the most substantial evidence for increases in quality of life. Few organizational interventions were identified, with highly heterogeneous components. Conclusion: Promoting healthcare workers' mental health is essential at an individual and health system level. This review identifies several promising practices that could be used to support healthcare workers at risk of adverse mental health outcomes as they respond to future public health emergencies.Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=203810, identifier #CRD42020203810 (PROSPERO).

The Impact of an Electronic Best Practice Advisory on Patients' Physical Activity and Cardiovascular Risk Profile.

BACKGROUND: Regular physical activity (PA) is a component of cardiovascular health and is associated with a lower risk of cardiovascular disease (CVD). However, only about half of US adults achieved the current PA recommendations. OBJECTIVE: The study purpose was to implement PA counseling using a clinical decision support tool in a preventive cardiology clinic and to assess changes in CVD risk factors in a sample of patients enrolled over 12 weeks of PA monitoring. METHODS: This intervention, piloted for 1 year, had 3 components embedded in the electronic health record: assessment of patients' PA, an electronic prompt for providers to counsel patients reporting low PA, and patient monitoring using a Fitbit. Cardiovascular disease risk factors included PA (self-report and Fitbit), body mass index, blood pressure, lipids, and cardiorespiratory fitness assessed with the 6-minute walk test. Depression and quality of life were also assessed. Paired t tests assessed changes in CVD risk. RESULTS: The sample who enrolled in the remote patient monitoring (n = 59) were primarily female (51%), White adults (76%) with a mean age of 61.13 ± 11.6 years. Self-reported PA significantly improved over 12 weeks (P = .005), but not Fitbit steps (P = .07). There was a significant improvement in cardiorespiratory fitness (469 ± 108 vs 494 ± 132 m, P = .0034), and 23 participants (42%) improved at least 25 m, signifying a clinically meaningful improvement. Only 4 participants were lost to follow-up over 12 weeks of monitoring. CONCLUSIONS: Patients may need more frequent reminders to be active after an initial counseling session, perhaps getting automated messages based on their step counts syncing to their electronic health record.

Limitations of COVID-19 testing and case data for evidence-informed health policy and practice.

BACKGROUND: Coronavirus disease 2019 (COVID-19) became a pandemic within a matter of months. Analysing the first year of the pandemic, data and surveillance gaps have subsequently surfaced. Yet, policy decisions and public trust in their country's strategies in combating COVID-19 rely on case numbers, death numbers and other unfamiliar metrics. There are many limitations on COVID-19 case counts internationally, which make cross-country comparisons of raw data and policy responses difficult. PURPOSE AND CONCLUSIONS: This paper presents and describes steps in the testing and reporting process, with examples from a number of countries of barriers encountered in each step, all of which create an undercount of COVID-19 cases. This work raises factors to consider in COVID-19 data and provides recommendations to inform the current situation with COVID-19 as well as issues to be aware of in future pandemics.

Paraganglioma in pregnancy: A case series and literature review.

Paragangliomas are rare neuroendocrine neoplasms which are often catecholamine-secreting and associated with familial syndromes. Described here are three women with a variety of pathology: isolated secretory paraganglioma diagnosed in pregnancy, secretory metastatic paraganglioma in pregnancy and non-secretory metastatic paraganglioma in pregnancy. Whilst paragangliomas are associated with morbidity and mortality during pregnancy, good maternal and fetal outcomes can be achieved through individualised care within the context of a multidisciplinary team. Although paragangliomas are associated with morbidity and mortality in pregnancy, good maternal and fetal outcomes can be achieved through individualised care within the context of a multidisciplinary team.

Pregnancy outcomes among women with type 1 diabetes mellitus using continuous subcutaneous insulin infusion versus multiple daily injections: A retrospective cohort study.

BACKGROUND: Insulin delivery options for pregnant women with type 1 diabetes mellitus are either continuous subcutaneous insulin infusion or multiple daily injections. The aim of this paper is to compare pregnancy outcomes in women with type 1 diabetes mellitus using continuous subcutaneous insulin infusion or multiple daily injections in pregnancy. METHODS: Retrospective single-centre cohort study of 298 pregnancies booked between 2006 and 2016. Descriptive analysis was performed for HbA1c values. Logistic regression models were created to compare selected maternal and neonatal outcomes. RESULTS: Continuous subcutaneous insulin infusion was associated with increased risk of large-for-gestational age (aOR 2.00, 95% CI 1.20-3.34) and preterm neonates (aOR 1.80, 95% CI 1.04-3.03). Continuous subcutaneous insulin infusion had no association with increased risk of adverse pregnancy outcomes. No difference in HbA1c values existed between groups. CONCLUSION: Using continuous subcutaneous insulin infusion for type 1 diabetes mellitus through pregnancy is associated with increased risk of large-for-gestational age and preterm neonates, without increased risk of associated adverse maternal or neonatal outcomes.

Evidence for type-specific DNA methylation patterns in epilepsy: a discordant monozygotic twin approach.

Aim: Epilepsy is a common neurological disorder characterized by recurrent seizures. We performed epigenetic analyses between and within 15 monozygotic (MZ) twin pairs discordant for focal or generalized epilepsy. Methods: DNA methylation analysis was performed using Illumina Infinium MethylationEPIC arrays, in blood and buccal samples. Results: Differentially methylated regions between epilepsy types associated with PM20D1 and GFPT2 genes in both tissues. Within MZ discordant twin pairs, differentially methylated regions associated with OTX1 and ARID5B genes for generalized epilepsy and TTC39C and DLX5 genes for focal epilepsy. Conclusion: This is the first epigenome-wide association study, utilizing the discordant MZ co-twin model, to deepen our understanding of the neurobiology of epilepsy.

Recombinant adeno-associated viral (rAAV) vectors mediate efficient gene transduction in cultured neonatal and adult microglia.

Microglia are a specialized population of myeloid cells that mediate CNS innate immune responses. Efforts to identify the cellular and molecular mechanisms that regulate microglia behaviors have been hampered by the lack of effective tools for manipulating gene expression. Cultured microglia are refractory to most chemical and electrical transfection methods, yielding little or no gene delivery and causing toxicity and/or inflammatory activation. Recombinant adeno-associated viral (rAAVs) vectors are non-enveloped, single-stranded DNA vectors commonly used to transduce many primary cell types and tissues. In this study, we evaluated the feasibility and efficiency of utilizing rAAV serotype 2 (rAAV2) to modulate gene expression in cultured microglia. rAAV2 yields high transduction and causes minimal toxicity or inflammatory response in both neonatal and adult microglia. To demonstrate that rAAV transduction can induce functional protein expression, we used rAAV2 expressing Cre recombinase to successfully excise a LoxP-flanked miR155 gene in cultured microglia. We further evaluated rAAV serotypes 5, 6, 8, and 9, and observed that all efficiently transduced cultured microglia to varying degrees of success and caused little or no alteration in inflammatory gene expression. These results provide strong encouragement for the application of rAAV-mediated gene expression in microglia for mechanistic and therapeutic purposes. Neonatal microglia are functionally distinct from adult microglia, although the majority of in vitro studies utilize rodent neonatal microglia cultures because of difficulties of culturing adult cells. In addition, cultured microglia are refractory to most methods for modifying gene expression. Here, we developed a novel protocol for culturing adult microglia and evaluated the feasibility and efficiency of utilizing Recombinant Adeno-Associated Virus (rAAV) to modulate gene expression in cultured microglia.

Glia: guardians, gluttons, or guides for the maintenance of neuronal connectivity?

An emerging aspect of neuronal-glial interactions is the connection glial cells have to synapses. Mounting research now suggests a far more intimate relationship than previously recognized. Moreover, the current evidence implicating synapse loss in neurodegenerative disease etiology is overwhelming, but the role of glia in the process of synaptic degeneration has only recently been considered in earnest. Each main class of glial cell, including astrocytes, oligodendrocytes, and microglia, performs crucial and multifaceted roles in the maintenance of synaptic function and excitability. As such, aging and/or neuronal stress from disease-related misfolded proteins may involve disruption of multiple non-cell-autonomous synaptic support systems that are mediated by neighboring glia. In addition, glial cell activation induced by injury, ischemia, or neurodegeneration is thought to greatly alter the behavior of glial cells toward neuronal synapses, suggesting that neuroinflammation potentially contributes to synapse loss primarily mediated by altered glial functions. This review discusses recent evidence highlighting novel roles for glial cells at neuronal synapses and in the maintenance of neuronal connectivity, focusing primarily on their implications for neurodegenerative disease research.

The p53 transcription factor modulates microglia behavior through microRNA-dependent regulation of c-Maf.

Neuroinflammation occurs in acute and chronic CNS injury, including stroke, traumatic brain injury, and neurodegenerative diseases. Microglia are specialized resident myeloid cells that mediate CNS innate immune responses. Disease-relevant stimuli, such as reactive oxygen species (ROS), can influence microglia activation. Previously, we observed that p53, a ROS-responsive transcription factor, modulates microglia behaviors in vitro and in vivo, promoting proinflammatory functions and suppressing downregulation of the inflammatory response and tissue repair. In this article we describe a novel mechanism by which p53 modulates the functional differentiation of microglia both in vitro and in vivo. Adult microglia from p53-deficient mice have increased expression of the anti-inflammatory transcription factor c-Maf. To determine how p53 negatively regulates c-Maf, we examined the impact of p53 on known c-Maf regulators. MiR-155 is a microRNA that targets c-Maf. We observed that cytokine-induced expression of miR-155 was suppressed in p53-deficient microglia. Furthermore, Twist2, a transcriptional activator of c-Maf, is increased in p53-deficient microglia. We identified recognition sites in the 3' untranslated region of Twist2 mRNA that are predicted to interact with two p53-dependent microRNAs: miR-34a and miR-145. In this article, we demonstrate that miR-34a and -145 are regulated by p53 and negatively regulate Twist2 and c-Maf expression in microglia and the RAW macrophage cell line. Taken together, these findings support the hypothesis that p53 activation induced by local ROS or accumulated DNA damage influences microglia functions and that one specific molecular target of p53 in microglia is c-Maf.

Transcription factor p53 influences microglial activation phenotype.

Several neurodegenerative diseases are influenced by the innate immune response in the central nervous system (CNS). Microglia have proinflammatory and subsequently neurotoxic actions as well as anti-inflammatory functions that promote recovery and repair. Very little is known about the transcriptional control of these specific microglial behaviors. We have previously shown that in HIV-associated neurocognitive disorders (HAND), the transcription factor p53 accumulates in microglia and that microglial p53 expression is required for the in vitro neurotoxicity of the HIV coat glycoprotein gp120. These findings suggested a novel function for p53 in regulating microglial activation. Here, we report that in the absence of p53, microglia demonstrate a blunted response to interferon-γ, failing to increase expression of genes associated with classical macrophage activation or secrete proinflammatory cytokines. Microarray analysis of global gene expression profiles revealed increased expression of genes associated with anti-inflammatory functions, phagocytosis, and tissue repair in p53 knockout (p53(-/-)) microglia compared with those cultured from strain matched p53 expressing (p53(+/+)) mice. We further observed that p53(-/-) microglia demonstrate increased phagocytic activity in vitro and expression of markers for alternative macrophage activation both in vitro and in vivo. In HAND brain tissue, the alternative activation marker CD163 was expressed in a separate subset of microglia than those demonstrating p53 accumulation. These data suggest that p53 influences microglial behavior, supporting the adoption of a proinflammatory phenotype, while p53 deficiency promotes phagocytosis and gene expression associated with alternative activation and anti-inflammatory functions.

RNA interference in Schistosoma mansoni schistosomula: selectivity, sensitivity and operation for larger-scale screening.

BACKGROUND: The possible emergence of resistance to the only available drug for schistosomiasis spurs drug discovery that has been recently incentivized by the availability of improved transcriptome and genome sequence information. Transient RNAi has emerged as a straightforward and important technique to interrogate that information through decreased or loss of gene function and identify potential drug targets. To date, RNAi studies in schistosome stages infecting humans have focused on single (or up to 3) genes of interest. Therefore, in the context of standardizing larger RNAi screens, data are limited on the extent of possible off-targeting effects, gene-to-gene variability in RNAi efficiency and the operational capabilities and limits of RNAi. METHODOLOGY/PRINCIPAL FINDINGS: We investigated in vitro the sensitivity and selectivity of RNAi using double-stranded (ds)RNA (approximately 500 bp) designed to target 11 Schistosoma mansoni genes that are expressed in different tissues; the gut, tegument and otherwise. Among the genes investigated were 5 that had been previously predicted to be essential for parasite survival. We employed mechanically transformed schistosomula that are relevant to parasitism in humans, amenable to screen automation and easier to obtain in greater numbers than adult parasites. The operational parameters investigated included defined culture media for optimal parasite maintenance, transfection strategy, time- and dose-dependency of RNAi, and dosing limits. Of 7 defined culture media tested, Basch Medium 169 was optimal for parasite maintenance. RNAi was best achieved by co-incubating parasites and dsRNA (standardized to 30 µg/ml for 6 days); electroporation provided no added benefit. RNAi, including interference of more than one transcript, was selective to the gene target(s) within the pools of transcripts representative of each tissue. Concentrations of dsRNA above 90 µg/ml were directly toxic. RNAi efficiency was transcript-dependent (from 40 to >75% knockdown relative to controls) and this may have contributed to the lack of obvious phenotypes observed, even after prolonged incubations of 3 weeks. Within minutes of their mechanical preparation from cercariae, schistosomula accumulated fluorescent macromolecules in the gut indicating that the gut is an important route through which RNAi is expedited in the developing parasite. CONCLUSIONS: Transient RNAi operates gene-selectively in S. mansoni newly transformed schistosomula yet the sensitivity of individual gene targets varies. These findings and the operational parameters defined will facilitate larger RNAi screens.

A nonazole CYP51 inhibitor cures Chagas' disease in a mouse model of acute infection.

Chagas' disease, the leading cause of heart failure in Latin America, is caused by the kinetoplastid protozoan Trypanosoma cruzi. The sterols of T. cruzi resemble those of fungi, both in composition and in biosynthesis. Azole inhibitors of sterol 14alpha-demethylase (CYP51) successfully treat fungal infections in humans, and efforts to adapt the success of antifungal azoles posaconazole and ravuconazole as second-use agents for Chagas' disease are under way. However, to address concerns about the use of azoles for Chagas' disease, including drug resistance and cost, the rational design of nonazole CYP51 inhibitors can provide promising alternative drug chemotypes. We report the curative effect of the nonazole CYP51 inhibitor LP10 in an acute mouse model of T. cruzi infection. Mice treated with an oral dose of 40 mg LP10/kg of body weight twice a day (BID) for 30 days, initiated 24 h postinfection, showed no signs of acute disease and had histologically normal tissues after 6 months. A very stringent test of cure showed that 4/5 mice had negative PCR results for T. cruzi, and parasites were amplified by hemoculture in only two treated mice. These results compare favorably with those reported for posaconazole. Electron microscopy and gas chromatography-mass spectrometry (GC-MS) analysis of sterol composition confirmed that treatment with LP10 blocked the 14alpha-demethylation step and induced breakdown of parasite cell membranes, culminating in severe ultrastructural and morphological alterations and death of the clinically relevant amastigote stage of the parasite.

Changes in synaptic populations in the spinal dorsal horn following a dorsal rhizotomy in the monkey.

Studies in monkeys have shown substantial neuronal reorganization and behavioral recovery during the months following a cervical dorsal root lesion (DRL; Darian-Smith [2004] J. Comp. Neurol. 470:134-150; Darian-Smith and Ciferri [2005] J. Comp. Neurol. 491:27-45, [2006] J. Comp. Neurol. 498:552-565). The goal of the present study was to identify ultrastructural synaptic changes post-DRL within the dorsal horn (DH). Two monkeys received a unilateral DRL, as described previously (Darian-Smith and Brown [2000] Nat. Neurosci. 3:476-481), which removed cutaneous and proprioceptive input from the thumb, index finger, and middle finger. Six weeks before terminating the experiment at 4 post-DRL months, hand representation was mapped electrophysiologically within the somatosensory cortex, and anterograde tracers were injected into reactivated cortex to label corticospinal terminals. Sections were collected through the spinal lesion zone. Corticospinal terminals and inhibitory profiles were visualized by using preembedding immunohistochemistry and postembedding gamma-aminobutyric acid (GABA) immunostaining, respectively. Synaptic elements were systematically counted through the superficial DH and included synaptic profiles with round vesicles (R), pleomorphic flattened vesicles (F; presumed inhibitory synapses), similar synapses immunolabeled for GABA (F-GABA), primary afferent synapses (C-type), synapses with dense-cored vesicles (D, mostly primary afferents), and presynaptic dendrites of interneurons (PSD). Synapse types were compared bilaterally via ANOVAs. As expected, we found a significant drop in C-type profiles on the lesioned side ( approximately 16% of contralateral), and R profiles did not differ bilaterally. More surprising was a significant increase in the number of F profiles ( approximately 170% of contralateral) and F-GABA profiles ( approximately 315% of contralateral) on the side of the lesion. Our results demonstrate a striking increase in the inhibitory circuitry within the deafferented DH.

Fragment-based discovery of hepatitis C virus NS5b RNA polymerase inhibitors.

Non-nucleoside inhibitors of HCV NS5b RNA polymerase were discovered by a fragment-based lead discovery approach, beginning with crystallographic fragment screening. The NS5b binding affinity and biochemical activity of fragment hits and inhibitors was determined by surface plasmon resonance (Biacore) and an enzyme inhibition assay, respectively. Crystallographic fragment screening hits with approximately 1-10mM binding affinity (K(D)) were iteratively optimized to give leads with approximately 200nM biochemical activity and low microM cellular activity in a Replicon assay.

Synthesis and evaluation of multisubstrate bicyclic pyrimidine nucleoside inhibitors of human thymidine phosphorylase.

A series of novel, multisubstrate, bicyclic pyrimidine nucleoside inhibitors of human thymidine phosphorylase (TP) is described. Thymidine phosphorylase has been implicated in angiogenesis and plays a significant role in tumor progression and metastasis. The presence and orientation of the phosphonate moiety (acting as a phosphate mimic) in these derivatives were critical for inhibitory activity. The most active compounds possessed a phosphonate group in an endo orientation. This was consistent with molecular modeling results that showed the endo isomer protein-ligand complex to be lower in energy than the exo complex.

The neurodegeneration sequence in prion diseases: evidence from functional, morphological and ultrastructural studies of the GABAergic system.

Loss of the GABAergic system of neurons has been reported to be the first detectable neuropathological change in prion diseases, which features the accumulation of an aberrant isoform of the prion protein (PrP(Sc)). To determine the timing of GABAergic system dysfunction and degeneration and its relationship to PrP(Sc) accumulation during the course of prion disease in Syrian hamsters, we applied 3 approaches: i) quantifying GABA-immunopositive neurons and their processes by light and electron microscopy to test for selective loss; ii) measuring evoked [3H]-GABA release from synaptosomes to test for functional abnormalities; and iii) determining the kinetics of PrP(Sc) accumulation in subcellular fractions to correlate it with GABAergic dysfunction. At the terminal stages of disease, we found a significant increase in the number of GABA-positive and -negative presynaptic boutons with abnormally aggregated synaptic vesicles. At the same stage, we also found an equal degree of GABA-immunopositive and -immunonegative presynaptic bouton loss. In contrast, GABA-positive neocortical cell bodies increased, based on stereologic estimates in the terminal stage of scrapie. In the context of these abnormalities, evoked release of [3H]-GABA from cortical and thalamic synaptosomes was significantly decreased, which correlated well with the accumulation of PrP(Sc) in synaptosomes and cell membrane fractions.

Progress toward a peptidomimetic of laminin-derived pentapeptide YIGSR: synthesis of the unique tricyclic core structure.

The peptide sequence YIGSR, a segment of the basement membrane matrix glycoprotein laminin, has been identified as a key component in tumor cell invasion. Guided by extensive NMR work and de novo design algorithms, a nonpeptide mimetic of this pentapeptide was identified as a lead candidate for synthesis. The target displays the key amino acid side chains from a novel tricyclic scaffold. The first synthesis of this unique scaffold is completed in 11 steps and 7% overall yield.