Multimorbidity in persons with non-traumatic spinal cord injury and its impact on healthcare utilization and health outcomes.

STUDY DESIGN: Cross-sectional survey in Canada. OBJECTIVES: To explore multimorbidity (the coexistence of two/more health conditions) in persons with non-traumatic spinal cord injury (NTSCI) and evaluate its impact on healthcare utilization (HCU) and health outcomes. SETTING: Community-dwelling persons. METHODS: Data from the Spinal Cord Injury Community Survey (SCICS) was used. A multimorbidity index (MMI) consisting of 30 secondary health conditions (SHCs), the 7-item HCU questionnaire, the Short Form-12 (SF-12), Life Satisfaction-11 first question, and single-item Quality of Life (QoL) measure were administered. Additionally, participants were grouped as "felt needed healthcare was received" (Group 1, n = 322) or "felt needed healthcare was not received" (Group 2, n = 89) using the HCU question. Associations among these variables were assessed using multivariable analysis. RESULTS: 408 of 412 (99%) participants with NTSCI reported multimorbidity. Constipation, spasticity, and fatigue were the most prevalent self-reported SHCs. Group 1 had a higher MMI score compared to Group 2 (p < 0.001). A higher MMI score correlated with the feeling of not receiving needed care (OR 1.4, 95% CI 1.08-1.21), lower SF-12 (physical/mental component summary scores), being unsatisfied with life, and lower QoL (all p < 0.001). Additionally, Group 1 had more females (p < 0.001), non-Caucasians (p = 0.034), and lower personal annual income (p = 0.025). CONCLUSIONS: Persons with NTSCI have multimorbidity, and the MMI score was associated with increased HCU and worse health outcomes. This work emphasizes the critical need for improved healthcare and monitoring. Future work determining specific thresholds for the MMI could be helpful for triage screening to identify persons at higher risk of poor outcomes.

The effect of rurality and distance from care on health outcomes, environmental barriers, and healthcare utilization patterns in persons with traumatic spinal cord injury.

STUDY DESIGN: Cohort study. OBJECTIVES: To evaluate the association between residential living location and health outcomes, environmental barriers, quality of life, and healthcare utilization patterns after traumatic spinal cord injury (tSCI). SETTING: Community setting, Atlantic Canada. METHODS: An ambispective study of data collected on a subset of individuals enrolled in the Rick Hansen Spinal Cord Injury Registry (RHSCIR) from 2012 to 2018. Outcomes were analyzed using two measures of rurality: postal codes at community follow-up (rural versus urban) and residential travel distance to the nearest RHSCIR facility (>100 km versus ≤100 km). Outcomes studied included the Craig Hospital Inventory of Environmental Factors-Short Form (CHIEF-SF), Short Form-36 Version 2 (SF36v2), Life Satisfaction Questionnaire (LISAT-11), Spinal Cord Independence Measure (SCIM), secondary health complications and healthcare utilization patterns. Outcomes were assessed 9 to 24 months post-discharge from initial hospitalization. RESULTS: 104 participants were studied, 21 rural and 83 urban based on postal codes at community follow-up. 59 participants lived more than 100 km away from the nearest RHSCIR facility, while 45 participants lived within 100 km. Individuals from urban area codes reported a greater magnitude of perceived barriers on the policies and work/school subscales of the CHIEF-SF. No differences in function, quality of life, and healthcare utilization patterns according to the measures of rurality were observed. Individuals living >100 km from the nearest RHSCIR facility reported greater rates of sexual dysfunction. CONCLUSIONS: Despite differences in environmental barriers, individuals from urban and rural locations in Eastern Canada reported similar health outcomes and quality of life after tSCI.

An international survey of the structure and process of care for traumatic spinal cord injury in acute and rehabilitation facilities: lessons learned from a pilot study.

BACKGROUND: To describe the key findings and lessons learned from an international pilot study that surveyed spinal cord injury programs in acute and rehabilitation facilities to understand the status of spinal cord injury care. METHODS: An online survey with two questionnaires, a 74-item for acute care and a 51-item for rehabilitation, was used. A subset of survey items relevant to the themes of specialized care, timeliness, patient-centeredness, and evidence-based care were operationalized as structure or process indicators. Percentages of facilities reporting the structure or process to be present, and percentages of indicators met by each facility were calculated and reported separately for facilities from high-income countries (HIC) and from low and middle-income countries (LMIC) to identify "hard to meet" indicators defined as those met by less than two-thirds of facilities and to describe performance level. RESULTS: A total of 26 acute and 26 rehabilitation facilities from 25 countries participated in the study. The comparison of the facilities based on the country income level revealed three general observations: 1) some indicators were met equally well by both HIC and LMIC, such as 24-hour access to CT scanners in acute care and out-patient services at rehabilitation facilities; 2) some indicators were hard to meet for LMIC but not for HIC, such as having a multidisciplinary team for both acute and rehabilitation settings; and 3) some indicators were hard to meet by both HIC and LMIC, including having peer counselling programs. Variability was also observed for the same indicator between acute and rehabilitation facilities, and a wide range in the total number of indicators met among HIC facilities (acute 59-100%; rehabilitation 36-100%) and among LMIC facilities (acute: 41-82%; rehabilitation: 36-93%) was reported. CONCLUSIONS: Results from this international pilot study found that the participating acute and rehabilitation facilities on average adhered to 74% of the selected indicators, suggesting that the structure and processes to provide ideal traumatic spinal cord injury care were broadly available. Recruiting a representative sample of SCI facilities and incorporating regional attributes in future surveys will be helpful to examine factors affecting adherence to indicators.

A geospatial examination of specialist care accessibility and impact on health outcomes for patients with acute traumatic spinal cord injury in New South Wales, Australia: a population record linkage study.

BACKGROUND: Timely treatment is essential for achieving optimal outcomes after traumatic spinal cord injury (TSCI), and expeditious transfer to a specialist spinal cord injury unit (SCIU) is recommended within 24 h from injury. Previous research in New South Wales (NSW) found only 57% of TSCI patients were admitted to SCIU for acute post-injury care; 73% transferred within 24 h from injury. We evaluated pre-hospital and inter-hospital transfer practices to better understand the post-injury care pathways impact on patient outcomes and highlight areas in the health service pathway that may benefit from improvement. METHODS: This record linkage study included administrative pre-hospital (Ambulance), admissions (Admitted Patients) and costs data obtained from the Centre for Health Record Linkage, NSW. All patients aged ≥16 years with incident TSCI in NSW (2013-2016) were included. We investigated impacts of geographical disparities on pre-hospital and inter-hospital transport decisions from injury location using geospatial methods. Outcomes assessed included time to SCIU, surgery and the impact of these variables on the experience of inpatient complications. RESULTS: Inclusion criteria identified 316 patients, geospatial analysis showed that over half (53%, n = 168) of all patients were injured within 60 min road travel of a SCIU, yet only 28.6% (n = 48) were directly transferred to a SCIU. Patients were more likely to experience direct transfer to a SCIU without comorbid trauma (p < 0.01) but higher ICISS (p < 0.001), cervical injury (p < 0.01), and transferred by air-ambulance (p < 0.01). Indirect transfer to SCIU was more likely with two or more additional traumatic injuries (p < 0.01) or incomplete injury (p < 0.01). Patients not admitted to SCIU at all were older (p = 0.05) with lower levels of injury (p < 0.01). Direct transfers received earlier operative intervention (median (IQR) 12.9(7.9) hours), compared with patients transferred indirectly to SCIU (median (IQR) 19.5(18.9) hours), and had lower risk of complications (OR 3.2 v 1.4, p < 0.001). Complications included pressure injury, deep vein thrombosis, urinary infection, among others. CONCLUSIONS: Getting patients with acute TSCI patients to the right place at the right time is dependent on numerous factors; some are still being triaged directly to non-trauma services which delays specialist and surgical care and increases complication risks. The higher rates of complication following delayed transfer to a SCIU should motivate health service policy makers to investigate reasons for this practice and consent to improvement strategies. More stringent adherence to recommended guidelines would prioritise direct SCIU transfer for patients injured within 60 min radius, enabling the benefits of specialised care.

Interaction of 4.1G and cGMP-gated channels in rod photoreceptor outer segments.

In photoreceptors, the assembly of signaling molecules into macromolecular complexes is important for phototransduction and maintaining the structural integrity of rod outer segments (ROSs). However, the molecular composition and formation of these complexes are poorly understood. Using immunoprecipitation and mass spectrometry, 4.1G was identified as a new interacting partner for the cyclic-nucleotide gated (CNG) channels in ROSs. 4.1G is a widely expressed multifunctional protein that plays a role in the assembly and stability of membrane protein complexes. Multiple splice variants of 4.1G were cloned from bovine retina. A smaller splice variant of 4.1G selectively interacted with CNG channels not associated with peripherin-2-CNG channel complex. A combination of truncation studies and domain-binding assays demonstrated that CNG channels selectively interacted with 4.1G through their FERM and CTD domains. Using immunofluorescence, labeling of 4.1G was seen to be punctate and partially colocalized with CNG channels in the ROS. Our studies indicate that 4.1G interacts with a subset of CNG channels in the ROS and implicate this protein-protein interaction in organizing the spatial arrangement of CNG channels in the plasma membrane of outer segments.

Changes in gene expression associated with retinal degeneration in the rd3 mouse.

PURPOSE: To identify and characterize changes in gene expression associated with photoreceptor degeneration in the rd3 mouse model of Leber congenital amaurosis (LCA) type 12. METHODS: Global genome expression profiling using microarray technology was performed on total RNA extracts from rd3 and wild-type control mouse retinas at postnatal day 21. Quantitative PCR analysis of selected transcripts was performed to validate the microarray results. RESULTS: Functional annotation of differentially regulated genes in the rd3 mouse defined key canonical pathways, including phototransduction, glycerophospholipid metabolism, tumor necrosis factor receptor 1 signaling, and endothelin signaling. Overall, 1,140 of approximately 55,800 transcripts were differentially represented. In particular, a large percentage of the upregulated transcripts encode proteins involved in the immune response; whereas the downregulated transcripts encode proteins involved in phototransduction and lipid metabolism. CONCLUSIONS: This analysis has elucidated several candidate genes and pathways, thus providing insight into the pathogenic mechanisms underlying the photoreceptor degeneration in the rd3 mouse retina and indicating directions for future studies.

Pronounced heritable variation and limited phenotypic plasticity in visual pigments and opsin expression of threespine stickleback photoreceptors.

Vertebrate colour vision is mediated by the differential expression of visual pigment proteins (opsins) in retinal cone photoreceptors. Many species alter opsin expression during life, either as part of development or as a result of changes in habitat. The latter, a result of phenotypic plasticity, appears common among fishes, but its cellular origin and ecological significance are unknown. Here, we used adult threespine stickleback fish from different photic regimes to investigate heritable variability and phenotypic plasticity in opsin expression. Fish from clear waters had double cones that expressed long (LWS) and middle (RH2) wavelength opsins, one per double cone member. In contrast, fish from red light-shifted lakes had double cones that were >95% LWS/LWS pairs. All fish had single cones that predominantly expressed a short wavelength (SWS2) opsin but ultraviolet cones, expressing a SWS1 opsin, were present throughout the retina. Fish from red light-shifted lakes, when transferred to clear waters, had a ∼2% increase in RH2/LWS double cones, though double cone density remained constant. Comparison of visual pigment absorbance and light transmission in the environment indicated that the opsin complements of double cones maximized sensitivity to the background light, whereas single cones had visual pigments that were spectrally offset from the dominant background wavelengths. Our results indicate that phenotypic plasticity in opsin expression is minor in sticklebacks and of questionable functional significance.

Role of the iridescent eye in stickleback female mate choice.

Many vertebrates exhibit prominent body colours that are used in courtship and territorial communication. Some fishes also have an eye whose iris becomes iridescent during the mating season, as in the threespine stickleback. Behavioural studies in this species have focused on the redness of the throat/jaw as the primary determinant of female mate choice. Unlike the iridescent eye, however, the red throat/jaw is not present in all stickleback populations, suggesting that the colour of the eye may be equally important for female mate choice. Here, we used data on photoreceptors and environmental light to assess body conspicuousness and the colour contrast of courtship signals for stickleback populations living in a range of waters, from clear (mesotrophic) to red light shifted (dystrophic). This analysis indicated that the redness of the throat/jaw is expressed to enhance the contrast of the eye. To test the importance of eye colour as a courtship signal, we carried out mate choice experiments in which females were presented with identical videos of a courting male but for the colour of the eye and/or the throat/jaw. Females did not choose based on differences in throat/jaw redness between videos, but preferred males with the highest contrast between the eye and the throat/jaw. This result points to the blue iridescent eye as a primary courtship signal in stickleback female mate choice.

Using the Standing and Walking Assessment Tool at Discharge Predicts Community Outdoor Walking Capacity in Persons With Traumatic Spinal Cord Injury.

OBJECTIVE: The Standing and Walking Assessment Tool (SWAT) standardizes the timing and content of walking assessments during inpatient rehabilitation by combining 12 stages ranging from lowest to highest function (0, 0.5, 1A, 1B, 1C, 2A, 2B, 2C, 3A, 3B, 3C, and 4) with 5 standard measures: the Berg Balance Scale, the modified Timed "Up & Go" test, the Activities-specific Balance Confidence Scale, the modified 6-Minute Walk Test, and the 10-Meter Walk Test (10MWT). This study aimed to determine if the SWAT at rehabilitation discharge could predict outdoor walking capacity 1-year after discharge in people with traumatic spinal cord injury. METHODS: This retrospective study used data obtained from the Rick Hansen Spinal Cord Injury Registry from 2014 to 2020. Community outdoor walking capacity was measured using the Spinal Cord Independence Measure III (SCIM III) outdoor mobility score obtained 12 (±4) months after discharge. Of 206 study participants, 90 were community nonwalkers (ie, SCIM III score 0-3), 41 were community walkers with aids (ie, SCIM III score 4-6), and 75 were independent community walkers (ie, SCIM III score 7-8). Bivariate, multivariable regression, and an area under the receiver operating characteristic curve analyses were performed. RESULTS: At rehabilitation discharge, 3 significant SWAT associations were confirmed: 0-3A with community nonwalkers, 3B/higher with community walkers with and without an aid, and 4 with independent community walkers. Moreover, at discharge, a higher (Berg Balance Scale, Activities-specific Balance Confidence Scale), faster (modified Timed "Up & Go," 10MWT), or further (10MWT) SWAT measure was significantly associated with independent community walking. Multivariable analysis indicated that all SWAT measures, except the 10MWT were significant predictors of independent community walking. Furthermore, the Activities-Specific Balance Confidence Scale had the highest area under the receiver operating characteristic score (0.91), demonstrating an excellent ability to distinguish community walkers with aids from independent community walkers. CONCLUSION: The SWAT stage and measures at discharge can predict community outdoor walking capacity in persons with traumatic spinal cord injury. Notably, a patient's confidence in performing activities plays an important part in achieving walking ability in the community. IMPACT: The discharge SWAT is useful to optimize discharge planning.

Network analysis of multimorbidity and health outcomes among persons with spinal cord injury in Canada.

Introduction: Multimorbidity, defined as the coexistence of two or more health conditions, is common in persons with spinal cord injury (SCI). Network analysis is a powerful tool to visualize and examine the relationship within complex systems. We utilized network analysis to explore the relationship between 30 secondary health conditions (SHCs) and health outcomes in persons with traumatic (TSCI) and non-traumatic SCI (NTSCI). The study objectives were to (1) apply network models to the 2011-2012 Canadian SCI Community Survey dataset to identify key variables linking the SHCs measured by the Multimorbidity Index-30 (MMI-30) to healthcare utilization (HCU), health status, and quality of life (QoL), (2) create a short form of the MMI-30 based on network analysis, and (3) compare the network-derived MMI to the MMI-30 in persons with TSCI and NTSCI. Methods: Three network models (Gaussian Graphical, Ising, and Mixed Graphical) were created and analyzed using standard network measures (e.g., network centrality). Data analyzed included demographic and injury variables (e.g., age, sex, region of residence, date, injury severity), multimorbidity (using MMI-30), HCU (using the 7-item HCU questionnaire and classified as "felt needed care was not received" [HCU-FNCNR]), health status (using the 12-item Short Form survey [SF-12] Physical and Mental Component Summary [PCS-12 and MCS-12] score), and QoL (using the 11-item Life Satisfaction questionnaire [LiSAT-11] first question and a single item QoL measure). Results: Network analysis of 1,549 participants (TSCI: 1137 and NTSCI: 412) revealed strong connections between the independent nodes (30 SHCs) and the dependent nodes (HCU-FNCNR, PCS-12, MCS-12, LiSAT-11, and the QoL score). Additionally, network models identified that cancer, deep vein thrombosis/pulmonary embolism, diabetes, high blood pressure, and liver disease were isolated. Logistic regression analysis indicated the network-derived MMI-25 correlated with all health outcome measures (p <0.001) and was comparable to the MMI-30. Discussion: The network-derived MMI-25 was comparable to the MMI-30 and was associated with inadequate HCU, lower health status, and poor QoL. The MMI-25 shows promise as a follow-up screening tool to identify persons living with SCI at risk of having poor health outcomes.

Optimizing spinal cord injury care in Canada: Development of a framework for strategy and action.

National health strategies are integral in defining the vision and strategic direction for ensuring the health of a population or for a specific health area. To facilitate a national coordinated approach in spinal cord injury (SCI) research and care in Canada, Praxis Spinal Cord Institute, with support from national experts and funding from the Government of Canada, developed a national strategy to advance SCI care, health, and wellness based on previous SCI strategic documents. This paper describes the development process of the SCI Care for Canada: A Framework for Strategy and Action. Specifically, it covers the process of building on historical and existing work of SCI in Canada through a thorough review of literature to inform community consultations and co-creation design. Furthermore, this paper describes planning for communication, dissemination, and evaluation. The SCI Care Strategic Framework promotes an updated common understanding of the goals and vision of the SCI community, as well as strengths and priorities within the SCI system regarding care, health, and wellness. Additionally, it supports the coordination and scaling up of SCI advancements to make a sustainable impact nationwide focusing on the needs of people living with SCI.

Evaluation of the quality of published SCI clinical practice guidelines using the AGREE II instrument: Results from Can-SCIP expert panel.

INTRODUCTION: Spinal cord injury (SCI) is a complex condition with substantial adverse personal, social and economic impacts necessitating evidence-based inter-professional care. To date, limited studies have assessed the quality of clinical practice guidelines (CPGs) within SCI. The aim of this study is to evaluate the quality of the development process and methodological rigour of published SCI CPGs across the care continuum from pre-hospital to community-based care. METHODS: Electronic health databases and indexes were searched to identify English or French language CPGs within SCI published within the last nine years with specific evidence-based recommendations applicable to the Canadian health care setting. Eligible CPGs were evaluated using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument. RESULTS: A total of forty-one CPGs that met the inclusion criteria were appraised by at least four raters. There was high variability in quality. Twenty-seven CPGs achieved a good rigour of development domain score of >70%. Other standardized mean domain scores were scope and purpose (85.32%), stakeholder involvement (65.03%), clarity of presentation (84.81%), applicability (55.55%) and editorial independence (75.83%). The agreement between appraisers (intraclass correlation coefficient) was high (intraclass correlation coefficient > 0.80). CONCLUSION: There is a paucity of CPGs that address community-based specialized rehabilitation and community reintegration. Furthermore, many CPGs only focus on a single impairment at one time point in the care continuum. As SCI is a complex condition that results in multimorbidity and requires health monitoring and intervention across the lifespan, a rigorously developed CPG that addresses high-quality, interprofessional comprehensive care is needed.

Factors Associated with Recovery in Motor Strength, Walking Ability, and Bowel and Bladder Function after Traumatic Cauda Equina Injury.

Traumatic cauda equina injury (TCEI) is usually caused by spine injury at or below L1 and can result in motor and/or sensory impairments and/or neurogenic bowel and bladder. We examined factors associated with recovery in motor strength, walking ability, and bowel and bladder function to aid in prognosis and establishing rehabilitation goals. The analysis cohort was comprised of persons with acute TCEI enrolled in the Rick Hansen Spinal Cord Injury Registry. Multi-variable regression analysis was used to determine predictors for lower-extremity motor score (LEMS) at discharge, walking ability at discharge as assessed by the walking subscores of either the Functional Independence Measure (FIM) or Spinal Cord Independence Measure (SCIM), and improvement in bowel and bladder function as assessed by FIM-relevant subscores. Age, sex, neurological level and severity of injury, time from injury to surgery, rehabilitation onset, and length of stay were examined as potential confounders. The cohort included 214 participants. Median improvement in LEMS was 4 points. Fifty-two percent of participants were able to walk, and >20% recovered bowel and bladder function by rehabilitation discharge. Multi-variable analyses revealed that shorter time from injury to rehabilitation admission (onset) was a significant predictor for both improvement in walking ability and bowel function. Longer rehabilitation stay and being an older female were associated with improved bladder function. Our results suggest that persons with TCEI have a reasonable chance of recovery in walking ability and bowel and bladder function. This study provides important information for rehabilitation goals setting and communication with patients and their families regarding prognosis.

Interaction and localization of the retinitis pigmentosa protein RP2 and NSF in retinal photoreceptor cells.

RP2 is a ubiquitously expressed protein encoded by a gene associated with X-linked retinitis pigmentosa (XLRP), a retinal degenerative disease that causes severe vision loss. Previous in vitro studies have shown that RP2 binds to ADP ribosylation factor-like 3 (Arl3) and activates its intrinsic GTPase activity, but the function of RP2 in the retina, and in particular photoreceptor cells, remains unclear. To begin to define the role of RP2 in the retina and XLRP, we have conducted biochemical studies to identify proteins in retinal cell extracts that interact with RP2. Here, we show that RP2 interacts with N-ethylmaleimide sensitive factor (NSF) in retinal cells as well as cultured embryonic kidney (HEK293) cells by mass spectrometry-based proteomics and biochemical analysis. This interaction is mediated by the N-terminal domain of NSF. The E138G and DeltaI137 mutations of RP2 known to cause XLRP abolished the interaction of RP2 with the N-terminal domain of NSF. Immunofluorescence labeling studies further showed that RP2 colocalized with NSF in photoreceptors and other cells of the retina. Intense punctate staining of RP2 was observed close to the junction between the inner and outer segments beneath the connecting cilium, as well as within the synaptic region of rod and cone photoreceptors. Our studies indicate that RP2, in addition to serving as a regulator of Arl3, interacts with NSF, and this complex may play an important role in membrane protein trafficking in photoreceptors and other cells of the retina.

Opsin expression: new mechanism for modulating colour vision.

Each cone photoreceptor in the retina responds to light in a limited range of wavelengths, giving it a spectral phenotype. This phenotype is determined by the most prevalent of the photoreceptor's visual-pigment proteins (opsins) and is assumed to remain unchanged during an animal's lifetime. Here we show that in the Pacific pink salmon, Oncorhynchus gorbuscha, single cones can switch their spectral phenotype from ultraviolet to blue by regulating the production of the appropriate opsins as the fish grow older. This photoreceptor plasticity may operate to modulate colour vision as the salmon's lifestyle changes.

In-Hospital Mortality for the Elderly with Acute Traumatic Spinal Cord Injury.

As the incidence of traumatic spinal cord injury (tSCI) in the elderly rises, clinicians are increasingly faced with difficult discussions regarding aggressiveness of management, likelihood of recovery, and survival. Our objective was to outline risk factors associated with in-hospital mortality in elderly surgical and non-surgical patients following tSCI and to determine those unlikely to have a favorable outcome. Data from elderly patients (≥ 65 years of age) in the Canadian Rick Hansen SCI Registry from 2004 to 2017 were analyzed using descriptive analysis. Survival and mortality groups in each of the surgical and non-surgical group were compared to explore factors associated with in-hospital mortality and their impact, using logistical regression. Of 1340 elderly patients, 1018 had surgical data with 826 having had surgery. In the surgical group, the median time to death post-injury was 30 days with 75% dying within 50 days compared with 7 days and 20 days, respectively, in the non-surgical group. Significant predictors for in-hospital mortality following surgery are age, comorbidities, neurological injury severity (American Spinal Injury Association [ASIA] Impairment Scale [AIS]), and ventilation status. The odds of dying 50 days post-surgery are six times higher for patients ≥77 years of age versus those 65-76 years of age, five times higher for those with AIS A versus those with AIS B/C/D, and seven times higher for those who are ventilator dependent. An expected probability of dying within 50 days post-surgery was determined using these results. In-hospital mortality in the elderly after tSCI is high. The trend with age and time to death and the significant predictors of mortality identified in this study can be used to inform clinical decision making and discussions with patients and their families.

Cell-Specific Markers for the Identification of Retinal Cells and Subcellular Organelles by Immunofluorescence Microscopy.

Identification of specific cells and subcellular structures in the retina is fundamental for understanding the visual process, retinal development, disease progression, and therapeutic intervention. The increased use of knockout, transgenic, and naturally occurring mutant mice has further underlined the need for retinal cell-specific imaging. Immunofluorescence microscopy of retinal cryosections and whole-mount tissue labeled with cell-specific markers has emerged as the method of choice for identifying and quantifying specific cell populations and mapping their distribution within the retina. Immunofluorescence microscopy has also been important in localizing proteins to specific compartments of retinal cells. In most cases indirect labeling methods are employed in which lightly fixed retinal samples are first labeled with a primary antibody targeted against a cell-specific protein of interest and then labeled with a fluorescent dye-tagged secondary antibody that recognizes the primary antibody. The localization and relative abundance of the protein can be readily imaged under a conventional fluorescent or confocal scanning microscope. Immunofluorescence labeling can be adapted for imaging more than one antigen through the use of multiple antibodies and different, non-overlapping fluorescent dyes. A number of well-characterized immunochemical markers are now available for detecting photoreceptors, bipolar cells, amacrine cells, horizontal cells, Müller cells, and retinal pigment epithelial cells in the retina of mice and other mammals. Immunochemical markers are also available for visualizing the distribution of specific proteins within cells with most studies directed toward photoreceptor cells.

Growth hormone regulates opsin expression in the retina of a salmonid fish.

Colour vision relies on retinal photoreceptors that express a different predominant visual pigment protein (opsin). In several vertebrates, the primary opsin expressed by a photoreceptor can change throughout ontogeny, although the molecular factors that influence such regulation are poorly understood. One of these factors is thyroid hormone which, together with its receptors, modulates opsin expression in the retinas of multiple vertebrates including rodents and salmonid fishes. In the latter, thyroid hormone induces a switch in opsin expression from SWS1 (ultraviolet light sensitive) to SWS2 (short wavelength or blue light sensitive) in the single cone photoreceptors of the retina. The actions of other hormones on opsin expression have not been investigated. In the present study, we used a transgenic strain of coho salmon (Oncorhynchus kitsutch) with enhanced levels of circulating growth hormone compared to that of wild siblings to assess the effects of this hormone on the SWS1 to SWS2 opsin switch. Transgenic fish showed a developmentally accelerated opsin switch compared to size-matched controls as assessed by immunohistological and in situ hybridisation labelling of photoreceptors and by quantification of transcripts using quantitative polymerase chain reaction. This accelerated switch led to a different spectral sensitivity maximum, under a middle to long wavelength adapting background, from ultraviolet (λmax  ~ 380 nm) in controls to short wavelengths (λmax  ~ 430 nm) in transgenics, demonstrating altered colour vision. The effects of growth hormone over-expression were independent of circulating levels of thyroid hormone (triiodothyronine), the hormone typically associated with opsin switches in vertebrates.

The ultraviolet opsin is the first opsin expressed during retinal development of salmonid fishes.

PURPOSE: To determine the spatial and temporal progression of opsin appearance during retinal development of salmonid fishes (genus Oncorhynchus and Salmo). METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization with riboprobes against the five classes of opsins present in salmonids (UV, blue, green, red, and rhodopsin) were used to establish the sequence of opsin appearance and the localization of opsins to specific morphologic photoreceptor types. RESULTS: Both detection methods revealed that UV opsin mRNA was expressed first and was followed closely by red opsin mRNA. In situ hybridization results indicated the following opsin sequence: UV, red, rhodopsin, green, and blue. The UV opsin riboprobe labeled single cones, whereas the red and green riboprobes labeled opposite members of double cones. The blue riboprobe started labeling single center cones approximately 1 month after initial UV riboprobe labeling, confirming a switch in opsin expression of these cones from UV to blue. All probes first labeled a small patch of cells in the centrotemporal retina, and expression then expanded primarily toward the temporal and dorsal retina, with the exception of the blue opsin which expanded ventrally at first. CONCLUSIONS: The sequence of cone opsin appearance in salmonid fishes is similar to that in mammals, in which a violet-blue (SWS1) opsin is expressed first followed by a red (M/LWS) opsin. This sequence is different from that in zebrafish, goldfish, and chick, in which red and green opsins are expressed first. As in mammals, rhodopsin expression in salmonid fishes arises after the first cone opsin. The findings show similarity in the sequence of opsin expression between a group of lower vertebrates, the salmonid fishes, and mammals.

Impact of Therapy on Recovery during Rehabilitation in Patients with Traumatic Spinal Cord Injury.

Evidence-based planning of rehabilitation interventions is important to improving cost efficiency while maintaining patient and system outcomes. This article aims to explore the relationship between rehabilitation therapy, functional outcome, bed utilization, and care costs after traumatic spinal cord injury (tSCI). A retrospective review of 262 persons with tSCI admitted to an inpatient rehabilitation facility from 2005-2012 was conducted. Treatment variables and outcome measures included rehabilitation length of stay (LOS), days to rehabilitation (onset), hours and intensity of therapy, and Functional Independence Measure (FIM). Polynomial regression models and generalized additive models were applied to explore the relationship between therapy hours and motor FIM change. Simulation modeling was used to assess the impact of hypothetically increasing therapy intensity. Patients were grouped by injury as: C1-4 American Spinal Injury Association (ASIA) Impairment Scale (AIS) A,B,C; C5-8 AIS A,B,C; T1-S5 AIS A,B,C; and AIS D. The sample was 85% male, mean age 45.9, median LOS 102 days, and mean therapy intensity 5.7 h/week. Motor FIM change was positively associated with total hours of therapy (ß = 0.40, p < 0.0001) up to a certain time point, adjusted for age, gender, injury, complications, and rehabilitation onset. Hypothetically increasing therapy intensity by 50% and 100% resulted in average motor FIM efficiency gain ranging between 0.04-0.07 and 0.1-0.17, respectively, across injury groups. The hypothetical changes resulted in reductions in the average LOS and bed utilization rate, translating to cost savings of $20,000 and $50,000 (2011 CAD) for the +50% and +100% scenarios, respectively. The results highlight the importance of monitoring functional change throughout rehabilitation after tSCI and the need for customized therapeutic strategies.