Distinct roles of Bdnf I and Bdnf IV transcript variant expression in hippocampal neurons.

Brain-derived neurotrophic factor (Bdnf) plays a critical role in brain development, dendritic growth, synaptic plasticity, as well as learning and memory. The rodent Bdnf gene contains nine 5' non-coding exons (I-IXa), which are spliced to a common 3' coding exon (IX). Transcription of individual Bdnf variants, which all encode the same BDNF protein, is initiated at unique promoters upstream of each non-coding exon, enabling precise spatiotemporal and activity-dependent regulation of Bdnf expression. Although prior evidence suggests that Bdnf transcripts containing exon I (Bdnf I) or exon IV (Bdnf IV) are uniquely regulated by neuronal activity, the functional significance of different Bdnf transcript variants remains unclear. To investigate functional roles of activity-dependent Bdnf I and IV transcripts, we used a CRISPR activation system in which catalytically dead Cas9 fused to a transcriptional activator (VPR) is targeted to individual Bdnf promoters with single guide RNAs, resulting in transcript-specific Bdnf upregulation. Bdnf I upregulation is associated with gene expression changes linked to dendritic growth, while Bdnf IV upregulation is associated with genes that regulate protein catabolism. Upregulation of Bdnf I, but not Bdnf IV, increased mushroom spine density, volume, length, and head diameter, and also produced more complex dendritic arbors in cultured rat hippocampal neurons. In contrast, upregulation of Bdnf IV, but not Bdnf I, in the rat hippocampus attenuated contextual fear expression. Our data suggest that while Bdnf I and IV are both activity-dependent, BDNF produced from these promoters may serve unique cellular, synaptic, and behavioral functions.

Clinical safety and efficacy of microwave ablation for small renal masses.

PURPOSE: CT-guided MWA is a safe and effective tool that should be utilized in the treatment of small renal masses (SRMs). We aim to clarify the utility of CT-guided MWA by examining patient outcomes such as recurrence, treatment success, changes in renal function, and complications. METHODS: A retrospective review of consecutive patients with SRMs who underwent same day renal mass biopsy (RMB) and CT-guided MWA between 2015 and 2022 was performed. Treatment safety was assessed by 30-day complications according to the Clavien-Dindo system and change in eGFR >30 days post-procedure. Treatment efficacy was defined by local recurrence and incomplete treatment rates and calculated using the Kaplan-Meier method. RESULTS: A total of 108 renal masses were found in 104 patients. The overall complication rate was 7.4% (8/108), of which 4 were major complications (3.7%). For those with renal function available >30 days post ablation, the median eGFR was 47.2 (IQR: 36.0, 57), compared to 52.3 (IQR: 43.7, 61.5) pre-ablation, p<0.0001. 5-year local recurrence free survival was 86%. Among those with biopsy proven malignancy (n= 66), there were five local recurrences (7.54%) occurring at a median of 25.1 months (IQR 19.9, 36.2) and one case (1.5%) of incomplete treatment. CONCLUSIONS: As the medical field continues to evolve towards less invasive interventions, MWA offers a valuable tool in the management of renal masses. With low major complication and recurrence rates, our findings support the utility of CT-guided MWA as a tool for treatment of SRMs.

Climate change and variability impacts on grazing herds: Insights from a system dynamics approach for semi-arid Australian rangelands.

Grazing livestock are an important source of food and income for millions of people worldwide. Changes in mean climate and increasing climate variability are affecting grasslands' carrying capacity, thus threatening the livelihood of millions of people as well as the health of grassland ecosystems. Compared with cropping systems, relatively little is known about the impact of such climatic changes on grasslands and livestock productivity and the adaptation responses available to farmers. In this study, we analysed the relationship between changes in mean precipitation, precipitation variability, farming practices and grazing cattle using a system dynamics approach for a semi-arid Australian rangeland system. We found that forage production and animal stocking rates were significantly affected by drought intensities and durations as well as by long-term climate trends. After a drought event, herd size recovery times ranged from years to decades in the absence of proactive restocking through animal purchases. Decreases in the annual precipitation means or increases in the interannual (year-to-year) and intra-annual (month-to-month) precipitation variability, all reduced herd sizes. The contribution of farming practices versus climate effect on herd dynamics varied depending on the herd characteristics considered. Climate contributed the most to the variance in stocking rates, followed by forage productivity levels and feeding supplementation practices (with or without urea and molasses). While intensification strategies and favourable climates increased long-term herd sizes, they also resulted in larger reductions in animal numbers during droughts and raised total enteric methane emissions. In the face of future climate trends, the grazing sector will need to increase its adaptability. Understanding which farming strategies can be beneficial, where, and when, as well as the enabling mechanisms required to implement them, will be critical for effectively improving rangelands and the livelihoods of pastoralists worldwide.

Rho Kinase Inhibition as a Therapeutic for Progressive Supranuclear Palsy and Corticobasal Degeneration.

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are neurodegenerative four-repeat tauopathies with no cure. Mitigating pathogenic tau levels is a rational strategy for tauopathy treatment, but therapeutic targets with clinically available drugs are lacking. Here, we report that protein levels of the Rho-associated protein kinases (ROCK1 and ROCK2), p70 S6 kinase (S6K), and mammalian target of rapamycin (mTOR) were increased in PSP and CBD brains. RNAi depletion of ROCK1 or ROCK2 reduced tau mRNA and protein level in human neuroblastoma cells. However, additional phenotypes were observed under ROCK2 knockdown, including decreased S6K and phosphorylated mTOR levels. Pharmacologic inhibition of Rho kinases in neurons diminished detergent-soluble and -insoluble tau through a combination of autophagy enhancement and tau mRNA reduction. Fasudil, a clinically approved ROCK inhibitor, suppressed rough eye phenotype and mitigated pathogenic tau levels by inducing autophagic pathways in a Drosophila model of tauopathy. Collectively, these findings highlight the Rho kinases as rational therapeutic targets to combat tau accumulation in PSP and CBD. SIGNIFICANCE STATEMENT: Studies of progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) suggest that mitigating pathogenic tau levels is a rational strategy for tauopathy treatment. In this report, the Rho-associated protein kinases (ROCK1 and ROCK2) are identified as novel drug targets for PSP and CBD. We show that elevated insoluble tau levels are associated with increased ROCK1 and ROCK2 in PSP and CBD brains, whereas experiments in cellular and animal models identify pharmacologic inhibition of ROCKs as a mechanism-based approach to reduce tau levels. Our study correlates bona fide changes in PSP and CBD brains with cellular models, identifies drug targets, and tests the therapeutic in vivo.

Rho-associated protein kinase 1 (ROCK1) is increased in Alzheimer's disease and ROCK1 depletion reduces amyloid-ß levels in brain.

Alzheimer's disease (AD) is the leading cause of dementia and mitigating amyloid-ß (Aß) levels may serve as a rational therapeutic avenue to slow AD progression. Pharmacologic inhibition of the Rho-associated protein kinases (ROCK1 and ROCK2) is proposed to curb Aß levels, and mechanisms that underlie ROCK2's effects on Aß production are defined. How ROCK1 affects Aß generation remains a critical barrier. Here, we report that ROCK1 protein levels were elevated in mild cognitive impairment due to AD (MCI) and AD brains compared to controls. Aß42 oligomers marginally increased ROCK1 and ROCK2 protein levels in neurons but strongly induced phosphorylation of Lim kinase 1 (LIMK1), suggesting that Aß42 activates ROCKs. RNAi depletion of ROCK1 or ROCK2 suppressed endogenous Aß40 production in neurons, and Aß40 levels were reduced in brains of ROCK1 heterozygous knock-out mice compared to wild-type littermate controls. ROCK1 knockdown decreased amyloid precursor protein (APP), and treatment with bafilomycin accumulated APP levels in neurons depleted of ROCK1. These observations suggest that reduction of ROCK1 diminishes Aß levels by enhancing APP protein degradation. Collectively, these findings support the hypothesis that both ROCK1 and ROCK2 are therapeutic targets to combat Aß production in AD. Mitigating amyloid-ß (Aß) levels is a rational strategy for Alzheimer's disease (AD) treatment, however, therapeutic targets with clinically available drugs are lacking. We hypothesize that Aß accumulation in mild cognitive impairment because of AD (MCI) and AD activates the RhoA/ROCK pathway which in turn fuels production of Aß. Escalation of this cycle over the course of many years may contribute to the buildup of amyloid pathology in MCI and/or AD.

Global climate policy impacts on livestock, land use, livelihoods, and food security.

Recent research has shed light on the cost-effective contribution that agriculture can make to global greenhouse gas abatement; however, the resulting impacts on agricultural production, producer livelihoods, and food security remain largely unexplored. This paper provides an integrated assessment of the linkages between land-based climate policies, development, and food security, with a particular emphasis on abatement opportunities and impacts in the livestock sector. Targeting Annex I countries and exempting non-Annex I countries from land-based carbon policies on equity or food security grounds may result in significant leakage rates for livestock production and agriculture as a whole. We find that such leakage can be eliminated by supplying forest carbon sequestration incentives to non-Annex I countries. Furthermore, substantial additional global agricultural abatement can be attained by extending a greenhouse gas emissions tax to non-Annex I agricultural producers, while compensating them for their additional tax expenses. Because of their relatively large emissions intensities and limited abatement possibilities, ruminant meat producers face the greatest market adjustments to land-based climate policies. We also evaluate the impacts of climate policies on livelihoods and food consumption in developing countries. In the absence of non-Annex I abatement policies, these impacts are modest. However, strong income and food consumption impacts surface because of higher food costs after forest carbon sequestration is promoted at a global scale. Food consumption among unskilled labor households falls but rises for the representative farm households, because global agricultural supplies are restricted and farm prices rise sharply in the face of inelastic food demands.

Strategy for effective percutaneous drainage of pancreatic collections: results on 121 patients.

UNLABELLED: There is a lack of technical guidelines for image-guided percutaneous drainage (IGPD) of pancreatic fluid collections (PFCs). To fill that void, we present a strategy and guidelines for systematic IGPD for effective PFCs evacuation. METHODS: Institutional Review Board (IRB)-approved study of 121 pancreatitis patients with symptomatic PFCs that underwent IGPD. IGPD strategy aimed at evacuation of the PFCs compartments using vigorous catheter drainage and manipulations. PFCs resolution and patients' outcome were measured. RESULTS: Pancreatitis pathogenesis and etiology included: necrotizing, 79 patients (alcoholic, 40; biliary, 20; hyperlipidemia, 8; other, 11); traumatic, 32 patients; and chronic ductal, 10 patients (pseudocysts). An ipsilateral retroperitoneal access was used for pararenal spaces PFCs (61, 50% patients), a transabdominal IGPD approach for anterior PFCs (49 patients, 41%), an intercostal/subcostal access for left subphrenic PFCs (22 patients, 18%), and a transgastric drainage route for retrogastric PFCs (9 patients, 7%). Table 1 lists the site of the pancreatic fluid collections and number and size of the catheter(s) used for IGPD of the PFCs in the 121 patients. Fifty-seven (47%) patients had positive cultures PFCs. Of these, 24 (20%) had polymicrobial infections, and 18 (15%) had fungal infections. There were 20 (11%) patients with multi-compartment drainage. PFCs resolution occurred in 102 (84%) patients. PFCs recurrence was treated by surgery (four patients) or IGPD (one patient). Pancreatic fistulas closed, except in one patient. Nine patients (7%) experienced multiorgan failure/death; 5 (4%) were lost to follow-up.

Distinct roles of Bdnf I and Bdnf IV transcript variant expression in hippocampal neurons.

Brain-derived neurotrophic factor (Bdnf) plays a critical role in brain development, dendritic growth, synaptic plasticity, as well as learning and memory. The rodent Bdnf gene contains nine 5' non-coding exons (I-IXa), which are spliced to a common 3' coding exon (IX). Transcription of individual Bdnf variants, which all encode the same BDNF protein, is initiated at unique promoters upstream of each non-coding exon, enabling precise spatiotemporal and activity-dependent regulation of Bdnf expression. Although prior evidence suggests that Bdnf transcripts containing exon I (Bdnf I) or exon IV (Bdnf IV) are uniquely regulated by neuronal activity, the functional significance of different Bdnf transcript variants remains unclear. To investigate functional roles of activity-dependent Bdnf I and IV transcripts, we used a CRISPR activation (CRISPRa) system in which catalytically-dead Cas9 (dCas9) fused to a transcriptional activator (VPR) is targeted to individual Bdnf promoters with single guide RNAs (sgRNAs), resulting in transcript-specific Bdnf upregulation. Bdnf I upregulation is associated with gene expression changes linked to dendritic growth, while Bdnf IV upregulation is associated with genes that regulate protein catabolism. Upregulation of Bdnf I, but not Bdnf IV, increased mushroom spine density, volume, length, and head diameter, and also produced more complex dendritic arbors in cultured rat hippocampal neurons. In contrast, upregulation of Bdnf IV, but not Bdnf I, in the rat hippocampus attenuated contextual fear expression. Our data suggest that while Bdnf I and IV are both activity-dependent, BDNF produced from these promoters may serve unique cellular, synaptic, and behavioral functions.

The SETD6 Methyltransferase Plays an Essential Role in Hippocampus-Dependent Memory Formation.

BACKGROUND: Epigenetic mechanisms are critical for hippocampus-dependent memory formation. Building on previous studies that implicate the N-lysine methyltransferase SETD6 in the activation of nuclear factor-κB RELA (also known as transcription factor p65) as an epigenetic recruiter, we hypothesized that SETD6 is a key player in the epigenetic control of long-term memory. METHODS: Using a series of molecular, biochemical, imaging, electrophysiological, and behavioral experiments, we interrogated the effects of short interfering RNA-mediated knockdown of Setd6 in the rat dorsal hippocampus during memory consolidation. RESULTS: Our findings demonstrate that SETD6 is necessary for memory-related nuclear factor-κB RELA methylation at lysine 310 and associated increases in H3K9me2 (histone H3 lysine 9 dimethylation) in the dorsal hippocampus and that SETD6 knockdown interferes with memory consolidation, alters gene expression patterns, and disrupts spine morphology. CONCLUSIONS: Together, these findings suggest that SETD6 plays a critical role in memory formation and may act as an upstream initiator of H3K9me2 changes in the hippocampus during memory consolidation.

Fasudil or genetic depletion of ROCK1 or ROCK2 induces anxiety-like behaviors.

Twenty-nine protein kinase inhibitors have been used to treat human diseases. Out of these, two are Rho-associated protein kinase (ROCK) 1 and 2 inhibitors. The ROCKs heavily influence neuronal architecture and structural plasticity, and ROCKs are putative drug targets for various brain disorders. While the pan-ROCK inhibitor Fasudil has been clinically approved to treat hypertension, heart failure, glaucoma, spinal cord injury, and stroke, a barrier to progress on this therapeutic avenue is the lack of experimental comparisons between pharmacologic and genetic manipulation of ROCKs. Our study begins to address this question using parallel approaches to study behavior in mice that were treated with Fasudil or were heterozygous for ROCK1 or ROCK2. Adult mice treated with Fasudil for thirty days displayed reduced time spent in the open arms of the elevated plus maze, whereas activity in the open field was more analogous to mock-treated animals. Both male and female adult ROCK1+/- and ROCK2+/- mice exhibited reduced time spent in open arms of the elevated plus maze compared to littermate controls. However, ROCK1 or ROCK2 heterozygosity did not alter performance in the open field or Y-maze. These results indicate that chronic treatment with Fasudil induces anxiety-like behaviors that are likely the consequence of ROCK1 and/or ROCK2 inhibition. Our findings may have implications for several ongoing clinical trials using Fasudil or other ROCK-based therapeutics.

Pharmacologic inhibition of LIMK1 provides dendritic spine resilience against ß-amyloid.

Alzheimer's disease (AD) therapies predominantly focus on ß-amyloid (Aß), but Aß effects may be maximal before clinical symptoms appear. Downstream of Aß, dendritic spine loss correlates most strongly with cognitive decline in AD. Rho-associated kinases (ROCK1 and ROCK2) regulate the actin cytoskeleton, and ROCK1 and ROCK2 protein abundances are increased in early AD. Here, we found that the increased abundance of ROCK1 in cultured primary rat hippocampal neurons reduced dendritic spine length through a myosin-based pathway, whereas the increased abundance of ROCK2 induced spine loss through the serine and threonine kinase LIMK1. Aß42 oligomers can activate ROCKs. Here, using static imaging studies combined with multielectrode array analyses, we found that the ROCK2-LIMK1 pathway mediated Aß42-induced spine degeneration and neuronal hyperexcitability. Live-cell microscopy revealed that pharmacologic inhibition of LIMK1 rendered dendritic spines resilient to Aß42 oligomers. Treatment of hAPP mice with a LIMK1 inhibitor rescued Aß-induced hippocampal spine loss and morphologic aberrations. Our data suggest that therapeutically targeting LIMK1 may provide dendritic spine resilience to Aß and therefore may benefit cognitively normal patients that are at high risk for developing dementia.

Clinical safety and efficacy of microwave ablation for small renal masses

ABSTRACT Purpose: CT-guided MWA is a safe and effective tool that should be utilized in the treatment of small renal masses (SRMs). We aim to clarify the utility of CT-guided MWA by examining patient outcomes such as recurrence, treatment success, changes in renal function, and complications. Methods: A retrospective review of consecutive patients with SRMs who underwent same day renal mass biopsy (RMB) and CT-guided MWA between 2015 and 2022 was performed. Treatment safety was assessed by 30-day complications according to the Clavien-Dindo system and change in eGFR >30 days post-procedure. Treatment efficacy was defined by local recurrence and incomplete treatment rates and calculated using the Kaplan-Meier method. Results: A total of 108 renal masses were found in 104 patients. The overall complication rate was 7.4% (8/108), of which 4 were major complications (3.7%). For those with renal function available >30 days post ablation, the median eGFR was 47.2 (IQR: 36.0, 57), compared to 52.3 (IQR: 43.7, 61.5) pre-ablation, p<0.0001. 5-year local recurrence free survival was 86%. Among those with biopsy proven malignancy (n= 66), there were five local recurrences (7.54%) occurring at a median of 25.1 months (IQR 19.9, 36.2) and one case (1.5%) of incomplete treatment. Conclusions: As the medical field continues to evolve towards less invasive interventions, MWA offers a valuable tool in the management of renal masses. With low major complication and recurrence rates, our findings support the utility of CT-guided MWA as a tool for treatment of SRMs.

Distinct and complementary functions of rho kinase isoforms ROCK1 and ROCK2 in prefrontal cortex structural plasticity.

Rho-associated protein kinases (ROCK) 1 and 2 are attractive drug targets for a range of neurologic disorders; however, a critical barrier to ROCK-based therapeutics is ambiguity over whether there are isoform-specific roles for ROCKs in neuronal structural plasticity. Here, we used a genetics approach to address this long-standing question by analyzing both male and female adult ROCK1+/- and ROCK2+/- mice compared to littermate controls. Individual pyramidal neurons in the medial prefrontal cortex (mPFC) were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. Increased apical and basal dendritic length and intersections were observed in ROCK1+/- but not ROCK2+/- mice. Although dendritic spine densities were comparable among genotypes, apical spine length was decreased in ROCK1+/- but increased in ROCK2+/- mice. Spine head and neck diameter were reduced similarly in ROCK1+/- and ROCK2+/- mice; however, certain spine morphologic subclasses were more affected than others in a genotype-dependent manner. Biochemical analyses of ROCK substrates in synaptic fractions revealed that phosphorylation of LIM kinase and cofilin were reduced in ROCK1+/- and ROCK2+/- mice, while phosphorylation of myosin light chain was decreased exclusively in ROCK1+/- mice. Collectively, these observations implicate ROCK1 as a novel regulatory factor of neuronal dendritic structure and detail distinct and complementary roles of ROCKs in mPFC dendritic spine structure.

α-Synuclein fibril-induced paradoxical structural and functional defects in hippocampal neurons.

Neuronal inclusions composed of α-synuclein (α-syn) characterize Parkinson's Disease (PD) and Dementia with Lewy bodies (DLB). Cognitive dysfunction defines DLB, and up to 80% of PD patients develop dementia. α-Syn inclusions are abundant in the hippocampus, yet functional consequences are unclear. To determine if pathologic α-syn causes neuronal defects, we induced endogenous α-syn to form inclusions resembling those found in diseased brains by treating hippocampal neurons with α-syn fibrils. At seven days after adding fibrils, α-syn inclusions are abundant in axons, but there is no cell death at this time point, allowing us to assess for potential alterations in neuronal function that are not caused by neuron death. We found that exposure of neurons to fibrils caused a significant reduction in mushroom spine densities, adding to the growing body of literature showing that altered spine morphology is a major pathologic phenotype in synucleinopathies. The reduction in spine densities occurred only in wild type neurons and not in neurons from α-syn knockout mice, suggesting that the changes in spine morphology result from fibril-induced corruption of endogenously expressed α-syn. Paradoxically, reduced postsynaptic spine density was accompanied by increased frequency of miniature excitatory postsynaptic currents (EPSCs) and presynaptic docked vesicles, suggesting enhanced presynaptic function. Action-potential dependent activity was unchanged, suggesting compensatory mechanisms responding to synaptic defects. Although activity at the level of the synapse was unchanged, neurons exposed to α-syn fibrils, showed reduced frequency and amplitudes of spontaneous Ca2+ transients. These findings open areas of research to determine the mechanisms that alter neuronal function in brain regions critical for cognition at time points before neuron death.

Natural climate solutions for the United States.

Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)-21 conservation, restoration, and improved land management interventions on natural and agricultural lands-to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year-1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year-1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.

Assessing the sustainable development and intensification potential of beef cattle production in Sumbawa, Indonesia, using a system dynamics approach.

The intensification of beef cattle production in dryland areas of East Indonesia has the potential to substantially raise the incomes of smallholder farmers that dominate the sector. In this study we assess the potential for intensifying beef production on Sumbawa Island, by introducing a household feedlot production system (2-20 animals) based on the Leucaena leucocephala (leucanea) tree legume as an improved source of feed. We used a system dynamics approach to model the entire value chain, accounting for herd dynamics, demand dynamics and seasonality. Our findings complement the growing body of biophysical evidence about the potential success of this intervention, by simulating improvements in the annual profitability for beef farmers in the project area of up to 415% by 2023. Increases in farm profit were shown to depend near equally on the higher productivity of the leucaena feeding system and an associated price premium, demonstrating the importance of supporting improved agricultural production with better marketing practices. The intervention was also shown to generate positive or neutral benefits for the main post-farm value chain actors. Importantly, it also reduced the GHG emission intensity of outputs from the beef herd by 16% by 2020. We explored number of scale-out pathways, including a relatively moderate pace of autonomous adoption for our main analysis, resulting in the accumulation of 3,444 hectares of leucaena 20-years after the initial project phase, which could sustain the fattening of 37,124 male cattle per year. More ambitious rates of scale-out were found to be possible without exceeding the animal and land resources of the island.

Mutant human torsinA, responsible for early-onset dystonia, dominantly suppresses GTPCH expression, dopamine levels and locomotion in Drosophila melanogaster.

Dystonia represents the third most common movement disorder in humans with over 20 genetic loci identified. TOR1A (DYT1), the gene responsible for the most common primary hereditary dystonia, encodes torsinA, an AAA ATPase family protein. Most cases of DYT1 dystonia are caused by a 3 bp (ΔGAG) deletion that results in the loss of a glutamic acid residue (ΔE302/303) in the carboxyl terminal region of torsinA. This torsinAΔE mutant protein has been speculated to act in a dominant-negative manner to decrease activity of wild type torsinA. Drosophila melanogaster has a single torsin-related gene, dtorsin. Null mutants of dtorsin exhibited locomotion defects in third instar larvae. Levels of dopamine and GTP cyclohydrolase (GTPCH) proteins were severely reduced in dtorsin-null brains. Further, the locomotion defect was rescued by the expression of human torsinA or feeding with dopamine. Here, we demonstrate that human torsinAΔE dominantly inhibited locomotion in larvae and adults when expressed in neurons using a pan-neuronal promoter Elav. Dopamine and tetrahydrobiopterin (BH4) levels were significantly reduced in larval brains and the expression level of GTPCH protein was severely impaired in adult and larval brains. When human torsinA and torsinAΔE were co-expressed in neurons in dtorsin-null larvae and adults, the locomotion rates and the expression levels of GTPCH protein were severely reduced. These results support the hypothesis that torsinAΔE inhibits wild type torsinA activity. Similarly, neuronal expression of a Drosophila DtorsinΔE equivalent mutation dominantly inhibited larval locomotion and GTPCH protein expression. These results indicate that both torsinAΔE and DtorsinΔE act in a dominant-negative manner. We also demonstrate that Dtorsin regulates GTPCH expression at the post-transcriptional level. This Drosophila model of DYT1 dystonia provides an important tool for studying the differences in the molecular function between the wild type and the mutant torsin proteins.

Adjustment of suboptimally placed lumbar pedicle screws decreases pullout strength and alters biomechanics of the construct: a pilot cadaveric study.

BACKGROUND: Lumbar pedicle screws are placed for internal fixation and help to enhance bony fusion. Optimal screws are medially directed, should be parallel or pointing to the superior endplate, and penetrate 50%-80% of the vertebral body. "Nonparallel" pedicle screws can be inadvertently placed within the confines of the pedicle and vertebral body but are sometimes replaced to obtain a more acceptable postoperative image. A nonparallel (suboptimal) screw is one that is located within the pedicle and body and does not violate bone; however, it is not parallel to the superior endplate. These "cored-out" grooves left in the bone from the initial tap and screw placement may compromise the integrity of the bone and the construct. METHODS: Dual-energy x-ray absorptiometry scans and L4-5 laminectomies were performed on 6 fresh-frozen cadaveric lumbar spines. We placed 2 optimal pedicle screws in L4, 1 optimal screw in L5, and 1 suboptimal screw in L5 (construct A). Axial rotation, flexion/extension, and lateral bending were tested. The suboptimal screw was repositioned in an optimal trajectory and retested (construct B). Pullout strength was performed on optimal and revised L5 pedicle screws. RESULTS: The mean axial rotation stiffness was 1.31 N-m/degrees ± 0.22 in construct A and 1.19 N-m/degrees ± 0.17 in construct B (P = 0.023; 95% CI [CI], 0.20-0.02). The mean lateral bending stiffness was 0.015 N/mm ± 0.002 in construct A and 0.016 N/mm ± 0.002 in construct B (P = 0.3; 95% CI, 0.0008-0.001). The mean flexion/extension stiffness was 0.0139 N/mm ± 0.002 in construct A and 0.0126 N/mm ± 0.002 in construct B (P = 0.01; 95% CI, 0.002-0.0004). Axial rotation and flexion/extension stiffness were significantly different between the 2 groups. The mean pullout strength was significantly higher in the nonrevised parallel screw group compared with the reimplanted parallel screw group (906.93 N ± 271.17 vs. 608.32 N ± 207.23, P = 0.031). Dual-energy x-ray absorptiometry imaging demonstrated 4 osteopenic and 2 osteoporotic specimens, although differences in bone mineral density did not play a significant role in assessing either the biomechanical parameters or the pullout strength. CONCLUSIONS: Great care is warranted in the initial placement of lumbar pedicle screws. Revising a nonparallel screw placement decreases pullout strength and alters biomechanical movements (axial rotation and flexion/extension) in patients with decreased bone mineral density. If a screw is inadvertently placed nonparallel to the endplate but is within the confines of the pedicle and vertebral body with adequate bone purchase, it should not be revised and rather be left in its place.

Carcinoma of the axillary tail of Spence: a case series.

There is sparse information about cancer in the axillary tail of Spence (CATS). Eight hundred and thirty-nine patients with breast cancer were retrospectively studied for the occurrence of CATS. Ten patients were identified based on detection by imaging studies. A tendency towards stage II or III disease, and estrogen and progesterone receptor-negative neoplasms in the older age (>45 years) group was observed. Management by conservative or radical surgery, with or without postoperative radiotherapy and chemotherapy, effected an estimated five-year disease-free survival rate of 67%, and rates of local failure, regional recurrence as well as distant metastasis of 0%, 10% and 30%, respectively. The treatment of CATS in accordance with modern day standards of care resulted in acceptable prognosis and disease control.

Development of an acoustic actuator for launch vehicle noise reduction.

In many active noise control applications, it is necessary that acoustic actuators be mounted in small enclosures due to volume constraints and in order to remain unobtrusive. However, the air spring of the enclosure is detrimental to the low-frequency performance of the actuator. For launch vehicle noise control applications, mass and volume constraints are very limiting, but the low-frequency performance of the actuator is critical. This work presents a novel approach that uses a nonlinear buckling suspension system and partial evacuation of the air within the enclosure to yield a compact, sealed acoustic driver that exhibits a very low natural frequency. Linear models of the device are presented and numerical simulations are given to illustrate the advantages of this design concept. An experimental prototype was built and measurements indicate that this design can significantly improve the low-frequency response of compact acoustic actuators.