Residential exposure associations with ALS risk, survival, and phenotype: a Michigan-based case-control study

Background: Environmental exposures impact amyotrophic lateral sclerosis (ALS) risk and progression, a fatal and progressive neurodegenerative disease. Better characterization of these exposures is needed to decrease disease burden. Objective: To identify exposures in the residential setting that associate with ALS risk, survival, and onset segment. Methods: ALS and control participants recruited from University of Michigan completed a survey that ascertained exposure risks in the residential setting. ALS risk was assessed using logistic regression models followed by latent profile analysis to consider exposure profiles. A case-only analysis considered the contribution of the residential exposure variables via a Cox proportional hazards model for survival outcomes and multinomial logistic regression for onset segment, a polytomous outcome. Results: This study included 367 ALS and 255 control participants. Twelve residential variables were associated with ALS risk after correcting for multiple comparison testing, with storage in an attached garage of chemical products including gasoline or kerosene (odds ratio (OR) = 1.14, padjusted < 0.001), gasoline-powered equipment (OR = 1.16, padjusted < 0.001), and lawn care products (OR = 1.15, padjusted < 0.001) representing the top three risk factors sorted by padjusted. Latent profile analysis indicated that storage of these chemical products in both attached and detached garages increased ALS risk. Although residential variables were not associated with poorer ALS survival following multiple testing corrections, storing pesticides, lawn care products, and woodworking supplies in the home were associated with shorter ALS survival using nominal p values. No exposures were associated with ALS onset segment. Conclusion: Residential exposures may be important modifiable components of the ALS susceptibility and prognosis exposome.

Avocational exposure associations with ALS risk, survival, and phenotype: A Michigan-based case-control study

INTRODUCTION

Environmental exposures strongly influence ALS risk and identification is needed to reduce ALS burden. Participation in hobbies and exercise may alter ALS risk and phenotype, warranting an assessment to understand their contribution to the ALS exposome.

METHODS

Participants with ALS and healthy controls were recruited from University of Michigan and self-completed a survey to ascertain hobbies, exercise, and avocational exposures. Exposure variables were associated with ALS risk, survival, onset segment, and onset age.

RESULTS

ALS (n = 400) and control (n = 287) participants self-reported avocational activities. Cases were slightly older (median age 63.0 vs. 61.1 years, p = 0.019) and had a lower educational attainment (p < 0.001) compared to controls; otherwise, demographics were well balanced. Risks associating with ALS after multiple comparison correction included golfing (odds ratio (OR) 3.48, padjusted = 0.004), recreational dancing (OR 2.00, padjusted = 0.040), performing gardening or yard work (OR 1.71, padjusted = 0.040) five years prior to ALS and personal (OR 1.76, padjusted = 0.047) or family (OR 2.21, padjusted = 0.040) participation in woodworking, and personal participation in hunting and shooting (OR 1.89, padjusted = 0.040). No exposures associated with ALS survival and onset. Those reporting swimming (3.86 years, padjusted = 0.016) and weightlifting (3.83 years, padjusted = 0.020) exercise 5 years prior to ALS onset had an earlier onset age.

DISCUSSION

The identified exposures in this study may represent important modifiable ALS factors that influence ALS phenotype. Thus, exposures related to hobbies and exercise should be captured in studies examining the ALS exposome.

Fast Blue and Cholera Toxin-B Survival Guide for Alpha-Motoneurons Labeling: Less Is Better in Young B6SJL Mice, but More Is Better in Aged C57Bl/J Mice

Fast Blue (FB) and Cholera Toxin-B (CTB) are two retrograde tracers extensively used to label alpha-motoneurons (α-MNs). The overall goals of the present study were to (1) assess the effectiveness of different FB and CTB protocols in labeling α-MNs, (2) compare the labeling quality of these tracers at standard concentrations reported in the literature (FB 2% and CTB 0.1%) versus lower concentrations to overcome tracer leakage, and (3) determine an optimal protocol for labeling α-MNs in young B6SJL and aged C57Bl/J mice (when axonal transport is disrupted by aging). Hindlimb muscles of young B6SJL and aged C57Bl/J mice were intramuscularly injected with different FB or CTB concentrations and then euthanized at either 3 or 5 days after injection. Measurements were performed to assess labeling quality via seven different parameters. Our results show that tracer protocols of lower concentration and shorter labeling durations were generally better in labeling young α-MNs, whereas tracer protocols of higher tracer concentration and longer labeling durations were generally better in labeling aged α-MNs. A 0.2%, 3-day FB protocol provided optimal labeling of young α-MNs without tracer leakage, whereas a 2%, 5-day FB protocol or 0.1% CTB protocol provided optimal labeling of aged α-MNs. These results inform future studies on the selection of optimal FB and CTB protocols for α-MNs labeling in normal, aging, and neurodegenerative disease conditions.

Unveiling the Effects of Stressors on Task Performance: The Role of Thriving at Work and Resilience

This study unveils the effects of stressors on employees' task performance through the mediating role of thriving at work (TAW) and a moderating role of resilience (RES) grounding on conservation of resources (COR) theory. The analysis of collected data from 331 supervisor-employee dyads in the hospitality sector of China explicates that the role conflict (RC) and perceived workload have a negative influence on TAW, and thriving has a positive relationship with task performance. The results corroborate the mediating role of TAW between RC, perceived workload, and task performance. Furthermore, the RES suppressed the negative relationship between RC, perceived workload, and TAW. Moreover, our study underscores the theoretical and practical contributions regarding the negative influence of stressors on TAW by exhibiting the importance of the COR mechanism for employees' behavioral outcomes.

Abstract WMP8: Results of Trevo Acute Ischemic Stroke Thrombectomy Registry: Predictors of Clinical Outcome

Background and Purpose: Recent randomized clinical trial (RCTs) demonstrated efficacy of mechanical thrombectomy using stent-retrievers in acute ischemic stroke (AIS) patients. The main purpose of TRevo ACute Ischemic StroKe (TRACK) stent-retriever thrombectomy multicenter registry is to demonstrate safety and efficacy in real life clinical practice.

Methods: The investigator-initiated TRACK multicenter registry recruited 24 sites in north America to submit demographic, clinical, site-adjudicated angiographic, and outcome data on consecutive AIS patients treated with Trevo stent-retriever device as the first treatment option. Standard clinical safety (symptomatic intracranial hemorrhage (sICH), and mortality) and efficacy (revascularization and disability) outcomes and predictors of clinical outcome were analyzed.

Results: 624 patients were enrolled in the TRACK registry. Median age was 68 years (range 16-94, 118 (18.1%) >80), male gender was 51.4%, and 67.7% were white. The median National Institutes of Health Stroke Severity Scale (NIHSS) was 17 (IQR 13-22). Transfer cases were 50.6% with IV-rtPA use in 318 cases (51.3%). Median onset to groin puncture (OTG) time was 283 min (IQR 198.5-443), and groin puncture to revascularization was 66 min (IQR 37.5-103). Anterior circulation occlusion was 86.2% (MCA/M2 in 55.2% followed by ICA in 15.9% and M2 in 12.7%). Use of GA was in 389 cases (62.3%), number of passes were ≤ 3 in 92% of the cases (1: 45.2%, 2:28%, and 3:18.7%), 291 (46.7%) had BGC use. Rescue use was seen in 21.7%. Revascularization of ≥ TIMI 2 was 81.8% and ≥ TICI 2b was 70%. The primary outcome of mRS of ≥ 2 was 48.3% in the full cohort, and 50.6% in TREVO-2 like group. sICH and mortality were 7.2%, and 20.1% in the full cohort vs 6.9% and 17.5% in the TREVO-2 like group, respectively. The independent predictors of clinical outcome were lower baseline NIHSS, younger age, use of BGC, successful recanalization, and no general anesthesia (GA).

Conclusions: The real life clinical practice Trevo registry demonstrated good clinical outcome and high rate of recanalization. Younger age, lower baseline NIHSS, use of balloon guide catheter, successful recanalization, and avoiding endotrachaeal GA independent predictors of good clinical outcome.

Reversible cerebral vasoconstriction syndrome: treatment with combined intra-arterial verapamil infusion and intracranial angioplasty

We report a case of severe RCVS treated with a combination of selective intra-arterial verapamil infusions and intracranial angioplasty, resulting in angiographic and clinical improvement. Endovascular techniques more commonly used in the treatment of SAH-induced vasospasm are potentially important adjuncts to systemic drug therapy in the management of severe RCVS.

Occlusion junctions do not improve stereoacuity

Occlusion geometry gives rise to interocular shifts in the positions of binocularly viewed contour junctions. Since these shifts do not give rise to normal binocular disparities, they have been called 'pseudodisparities'. Previous work has shown that the unmatched contour segments of a partially occluded contour at occlusion junctions can be used to recover the geometry of the occluding surface through the construction of 'illusory' contours. Here, experiments were performed to determine whether such junction shifts could enhance stereoscopic depth detection when the relative disparity between the contours was below threshold. Our results showed that stereoscopic depth detection does not improve when pseudodisparity is present. We conclude that the visual system is less sensitive to pseudodisparity than to conventional disparity information. We suggest that the primary role of pseudodisparity is to overcome conditions of camouflage.

Synchrony does not promote grouping in temporally structured displays

It has been proposed that the human visual system can use temporal synchrony to bind image regions into unified objects, as proposed in some neural models. Here we present experimental results from a new dynamic stimulus suggesting that previous evidence for this hypothesis can be explained with the well-established mechanisms of early visual processing, thus obviating the need to posit new synchrony-sensitive grouping mechanisms (see also ref. 5 for a critique of the binding by neural synchrony hypothesis).

Blind removal of lens distortion

Virtually all imaging devices introduce some amount of geometric lens distortion. A technique is presented for blindly removing these distortions in the absence of any calibration information or explicit knowledge of the imaging device. The basic approach exploits the fact that lens distortion introduces specific higher-order correlations in the frequency domain. These correlations can be detected by using tools from polyspectral analysis. The amount of distortion is then estimated by minimizing these correlations.

The perception of texture on folded surfaces

Do judgments of texture similarity reflect surface texture or image texture? To find out, we had observers view a rectangular surface that was folded into three panels, much like a brochure. Each panel was textured with an oriented noise pattern and the observers' task was to determine which side panel matched the center panel in surface texture. Information about surface geometry was conveyed by binocular disparity and by the boundaries of the rectangular surface. We found that observers were often consistently wrong, selecting the texture that differed in the image and not on the surface. In sharp contrast, when observers judged the texture orientation on each panel individually, their judgments were accurate reflections of the surface texture. So even when observers can recover surface texture, their judgments of texture similarity may still be based on image texture.

Blind inverse gamma correction

The luminance nonlinearity introduced by many imaging devices can often be described by a simple point-wise operation (gamma correction). This paper presents a technique for blindly estimating the amount of gamma correction in the absence of any calibration information or knowledge of the imaging device. The basic approach exploits the fact that gamma correction introduces specific higher-order correlations in the frequency domain. These correlations can be detected using tools from polyspectral analysis. The amount of gamma correction is then estimated by minimizing these correlations.

Sympathetic nervous system plays a role in postnatal eyeball enlargement in the rabbit

PURPOSE

To examine the role of ocular sympathetic activity in the enlargement of the rabbit eyeball during postnatal growth.

METHODS

Fourteen New Zealand albino rabbits aged 5 weeks underwent unilateral surgical transection of the cervical sympathetic trunk caudal to the superior cervical ganglion. Postoperative enlargement of both eyeballs was monitored by measuring the axial length and corneal diameters every 2 weeks for 22 weeks (7-27 weeks of age). Rabbits were housed under a 12-hour light/12-hour dark cycle, and the measurements were made in the middle of the light period. At a final age of 30 to 31 weeks, the refractive state of the whole eye was determined on both sides by measurement through the central cornea with a refractometer. Rabbits were then killed, eyeballs enucleated, and their ocular volumes determined.

RESULTS

From 9 weeks of age the axial length and corneal diameters were significantly shorter (P < 0.05) in the decentralized eye (surgical side) compared with the intact eye. This reduction remained statistically significant throughout the study period. However, the final refractive states of the two eyes were found not to be different. The mean ocular volume determined after postmortem enucleation was 4.5% less in the decentralized eye than in the intact eye (P < 0.05).

CONCLUSIONS

Sympathetic nervous system activity is involved in the normal enlargement of the rabbit eyeball during postnatal growth. However, removal of the ocular sympathetic tone at the age of 5 weeks does not significantly alter the refractive state of the eye when measured in young adulthood.

The effect of 3D structure on motion segmentation

A smooth surface imaged on the retina produces a smooth flow field. Thus, the visual system may group regions of smoothly varying flow to segment surfaces. We tested this idea by having observers perform a segmentation task on several stimuli that differed in their 3D interpretations but were all matched in the smoothness of their 2D flow fields. Performance varied across conditions with the best performance occurring when the stimulus stimulated a rigid plane. This result suggests that while observers may use deviations from smoothness to segment a broad class of motion stimuli, they use a more precise strategy to segment stimuli with a familiar 3D interpretation.

A new approach to the design of uniquely folded thermally stable proteins

A new computer program (CORE) is described that predicts core hydrophobic sequences of predetermined target protein structures. A novel scoring function is employed, which for the first time incorporates parameters directly correlated to free energies of unfolding (deltaGu), melting temperatures (Tm), and cooperativity. Metropolis-driven simulated annealing and low-temperature Monte Carlo sampling are used to optimize this score, generating sequences predicted to yield uniquely folded, stable proteins with cooperative unfolding transitions. The hydrophobic core residues of four natural proteins were predicted using CORE with the backbone structure and solvent exposed residues as input. In the two smaller proteins tested (Gbeta1, 11 core amino acids; 434 cro, 10 core amino acids), the native sequence was regenerated as well as the sequence of known thermally stable variants that exhibit cooperative denaturation transitions. Previously designed sequences of variants with lower thermal stability and weaker cooperativity were not predicted. In the two larger proteins tested (myoglobin, 32 core amino acids; methionine aminopeptidase, 63 core amino acids), sequences with corresponding side-chain conformations remarkably similar to that of native were predicted.

Separating reflections from images by use of independent component analysis

The image of an object can vary dramatically, depending on lighting, specularities, reflections, and shadows. It is often advantageous to separate these incidental variations from the intrinsic aspects of an image. We describe a method for photographing objects behind glass and digitally removing the reflections from the surface of the glass, leaving the image of the objects behind the glass intact. We describe the details of this method, which employs simple optical techniques and independent component analysis and show its efficacy with several examples.

Twenty-four-hour change in axial length in the rabbit eye

PURPOSE

To study the 24-hour changes in axial length, lens thickness, and anterior chamber depth in rabbits and to examine the role of ocular sympathetic activity on these changes.

METHODS

Young adult rabbits were entrained to a daily 12-hour light-12-hour dark cycle. Axial length, lens thickness, and anterior chamber depth were measured using ultrasonic techniques. In the first group of 12 rabbits, measurements were taken in the middle light phase and in the early dark phase. In the second group of 12 rabbits, measurements were taken in constant dark every 2 hours for a period of 24 hours. The latter group of rabbits underwent unilateral transection of the cervical sympathetic trunk. Three to four weeks later, axial length, lens thickness, and anterior chamber depth were measured again in constant dark every 2 hours for 24 hours.

RESULTS

Under the light- dark condition, axial length and anterior chamber depth were larger in the early dark phase than in the middle light phase. Lens thickness changed in the opposite direction. Under the constant-dark condition, axial length and anterior chamber depth changed gradually during the 24-hour period. The trough appeared in the late subjective light phase, and the peak appeared in the late subjective dark phase. Lens thickness remained relatively constant. In the eyes with decentralized ocular sympathetic nerves, 24-hour changes in axial length and anterior chamber depth occurred. However, magnitudes of nocturnal enlargement were relatively smaller than those in the intact eyes. Although larger in the decentralized eyes, lens thickness appeared unchanged in either eye for 24 hours.

CONCLUSIONS

Consistent 24-hour changes in axial length and anterior chamber depth occur in young adult rabbits. These changes are driven endogenously. Significant portions of the nocturnal enlargements of axial length and anterior chamber depth are unrelated to ocular sympathetic activity.

Range estimation by optical differentiation

We describe a novel formulation of the range recovery problem based on computation of the differential variation in image intensities with respect to changes in camera position. This method uses a single stationary camera and a pair of calibrated optical masks to measure this differential quantity directly. We also describe a variant based on changes in aperture size. The subsequent computation of the range image involves simple arithmetic operations and is suitable for real-time implementation. We present the theory of this technique and show results from a prototype camera that we have constructed.

Prediction and evaluation of side-chain conformations for protein backbone structures

A common approach to protein modeling is to propose a backbone structure based on homology or threading and then to attempt to build side chains onto this backbone. A fast algorithm using the simple criteria of atomic overlap and overall rotamer probability is proposed for this purpose. The method was first tested in the context of exhaustive searches of side chain configuration space in protein cores and was then applied to all side chains in 49 proteins of known structure, using simulated annealing to sample space. The latter procedure obtains the correct rotamer for 57% and the correct chi 1 value for 74% of the 6751 residues in the sample. When low-temperature Monte-Carlo simulations are initiated from the results of the simulated-annealing processes, consensus configurations are obtained which exhibit slightly more accurate predictions. The Monte-Carlo procedure also allows converged side chain entropies to be calculated for all residues. These prove to be accurate indicators of prediction reliability. For example, the correct rotamer is obtained for 79% and the correct chi 1 value is obtained for 84% of the half of the sample residues exhibiting the lowest entropies. Side chain entropy and predictability are nearly completely uncorrelated with solvent-accessible area. Some precedents for and implications of this observation are discussed.

Surgical management of massive splenomegaly

Recent reports document an increased mortality and morbidity associated with splenectomy for massive splenomegaly (<1000 g), with a morbidity that is 2 to 10-fold higher than that seen for splenectomy for normal size spleens. Preoperative angiographic embolization of the splenic artery has been advocated as a means to decrease this morbidity and mortality. In a retrospective review of 100 splenectomies performed at Kaiser Permanente (Los Angeles, CA), 20 were performed for splenomegaly, average weight 1811 g (1050-3700 g), and 80 were normal sized spleens. Mortality for normal sized spleens is 1.25 per cent, and for those performed for splenomegaly is zero. Likewise, the morbidity for splenectomy of normal sized spleens was 21.25 per cent, but for splenomegaly, a 20 per cent morbidity rate was observed. Average blood loss with splenomegaly was 696 mL, slightly higher than the 600 mL blood loss for normal sized spleens. Sixty-seven per cent of patients with splenomegaly required no transfusion, and none required more than two units. Of patients with normal size spleens, 75 per cent required no transfusion, and 96 per cent required two units or less. Splenectomy for splenomegaly is possible without an increase in morbidity or mortality. In this series, preoperative embolization was not performed; however, the morbidity and mortality rates compare favorably with series in which it was performed. Preoperative embolization of the splenic artery may be unnecessary and may expose the patient to additional expense, risk, and discomfort.

Steerable wedge filters for local orientation analysis

Steerable filters have been used to analyze local orientation patterns in imagery. Such filters are typically based on directional derivatives, whose symmetry produces orientation responses that are periodic with period pi, independent of image structure. We present a more general set of steerable filters that alleviate this problem.

Methods to decrease the morbidity of abdominoperineal resection

Recent reports stress that abdominoperineal resections (APR) are associated with many complications, including hemorrhage, long hospitalization, and delayed closure of an open perineal wound. Thirty-five patients underwent an abdominoperineal resection for cancer at Kaiser Permanente Medical Center, Los Angeles, from January 1989 to December 1993. All patients, except two, had their perineal wound closed after closure of the peritoneum and insertion of closed system suction catheters. Ninety-one per cent of patients achieved successful primary healing. Three patients (8.5%) suffered perineal wound dehiscence. Overall morbidity was 55 per cent, with urinary retention being the most common, occurring in 23 per cent of patients. This was managed successfully by early in-and-out self catheterization. There was no incidence of urinary tract infections. There were no operative deaths. Length of stay averaged 8.6 days, with a median of 7 days. Five patients had previous radiation therapy. Of those, two (40%) had perineal wound dehiscence, compared to only one of 33 (3.3%) patients without previous radiation. APRs can be done with minimal mortality, although with an increased morbidity in irradiated patients. Primary closure and drainage of the perineal wound significantly lowers the complication rate, as does early Foley removal and self in-and-out catheterization.