Canadian Stroke Best Practice Recommendations: Acute Stroke Management, 7th Edition Practice Guidelines Update, 2022

The 2022 update of the Canadian Stroke Best Practice Recommendations (CSBPR) for Acute Stroke Management, 7th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by an interdisciplinary team of healthcare providers and system planners caring for persons with an acute stroke or transient ischemic attack. These recommendations are a timely opportunity to reassess current processes to ensure efficient access to acute stroke diagnostics, treatments, and management strategies, proven to reduce mortality and morbidity. The topics covered include prehospital care, emergency department care, intravenous thrombolysis and endovascular thrombectomy (EVT), prevention and management of inhospital complications, vascular risk factor reduction, early rehabilitation, and end-of-life care. These recommendations pertain primarily to an acute ischemic vascular event. Notable changes in the 7th edition include recommendations pertaining the use of tenecteplase, thrombolysis as a bridging therapy prior to mechanical thrombectomy, dual antiplatelet therapy for stroke prevention, the management of symptomatic intracerebral hemorrhage following thrombolysis, acute stroke imaging, care of patients undergoing EVT, medical assistance in dying, and virtual stroke care. An explicit effort was made to address sex and gender differences wherever possible. The theme of the 7th edition of the CSBPR is building connections to optimize individual outcomes, recognizing that many people who present with acute stroke often also have multiple comorbid conditions, are medically more complex, and require a coordinated interdisciplinary approach for optimal recovery. Additional materials to support timely implementation and quality monitoring of these recommendations are available at www.strokebestpractices.ca.

Food insecurity and binge eating: A systematic review and meta-analysis

OBJECTIVE

This review synthesized literature on the relationship between food insecurity and binge eating.

METHODS

Relevant studies were identified by searching PubMed, CINAHL, PsycINFO, and gray literature from inception to October 2022. Eligible studies included primary research that assessed the relationship between food insecurity and binge eating. Data extraction was performed independently by two reviewers. Pooled odds ratios and 95% confidence intervals (CI) were obtained from random effect models with the R package meta. Analyses were stratified by binge eating versus binge-eating disorder (BED), study type (cross-sectional vs. longitudinal), and age (adults vs. adolescents).

RESULTS

We included 24 articles that reported on 20 studies, and 13 articles were included in the meta-analysis. Based on the random effects meta-analysis, the odds of adults in the food insecure group having binge eating were 1.66 (95% CI = 1.42, 1.93) times the odds of adults in the food secure group having binge eating. The odds of adults in the food insecure group having BED were 2.70 (95% CI = 1.47, 4.96) times the odds of adults in the food secure group having BED. Insufficient data were available for a meta-analysis on adolescents or longitudinal relationships.

CONCLUSIONS

These findings support that food insecurity is associated with binge eating in adults. There is a need for research to investigate the mechanisms underlying this relationship. Results highlight the importance of screening participants with food insecurity for disordered eating behaviors and vice versa. Future research is needed to examine whether interventions targeting food insecurity may help to mitigate disordered eating behaviors.

PUBLIC SIGNIFICANCE

Food insecurity is a common but under-recognized contributor to binge eating. In this article, we systematically reviewed research that has been published on the relationship between food insecurity and binge eating. We found support that food insecurity should be considered in the prevention and treatment of binge eating.

1024. Transitions of Care Quality Metrics in Patients Discharged on Parenteral Antimicrobial Therapy in a Large Urban Hospital that Lacks a Formal Outpatient Parenteral Antimicrobial Therapy Program

Background

With the evidence demonstrating the need for antimicrobial stewardship in the transition from inpatient to outpatient intravenous (IV) antibiotic therapy, it is imperative to have effective communication and coordination in a multidisciplinary team. Studies have demonstrated the utility of initiating a formal Outpatient Parenteral Antimicrobial Therapy (OPAT) program. The goal of this study is to assess quality metrics in a sample of patients discharged on IV antibiotics prior to initiation of a pilot OPAT program.

Methods

This is a retrospective, multicenter chart review of patients admitted to Temple University Health System from 10/1/2020 - 10/31/2021 who were discharged on IV antibiotics. There were no exclusion criteria. Patients with multiple admissions were documented as separate occurrences. Qualitative data were collected on the appropriateness of OPAT indication, pathogens targeted, antibiotics used, performance of infectious diseases (ID) consult, line selected, outcomes, and demographics. The primary endpoint is the percentage of global IV antibiotic prescribing errors (antibiotic, dose, route, frequency, duration, parenteral access device).

Results

There were 748 total discharges on IV antimicrobials in 705 unique patients. We chose a random sample of 109 discharges. Twenty (18%) had an oral antimicrobial available as an option. Antibiotic selection, dosing, duration, and access were correct 92%, 82%, 64% and 65% respectively (Table 2). ID recommended laboratory monitoring for 44 (40%) patients, of which 8 (18%) were sent to ID clinic; all had abnormal findings. Of the 25 patients who required ID follow-up, 11 had a scheduled ID appointment of which 8 attended. There was no mortality within 30 days from the 8 patients, but 2 were readmitted within 30 days. Overall, 39% patients readmitted within 30 days, 6% had mortality within 30 days and 50% were known to have completed therapy.

Conclusion

Our study captured a 65% rate of prescribing errors in a sample of 109 patients receiving IV antibiotics at discharge. The findings demonstrate an urgent need for an OPAT program to help with antimicrobial, parenteral access selection, monitoring, and follow-up with ID. By implementing this program, we hope to improve our ID follow-up, lab monitoring, and readmission metrics.

Disclosures

All Authors: No reported disclosures.

Occult Pulmonary Neuroendocrine Tumor Causing Severe Hyperparathyroidism: Diagnostic Challenges and Clinical Outcomes

Background/Objective

Ectopic tumoral production of parathyroid hormone (PTH) is rare. The incidence of hyperparathyroidism and osteitis fibrosa cystica (OFC) secondary to ectopic PTH secretion has only been reported in case reports, although infrequent.

Case Report

We report a case of a well-differentiated pulmonary neuroendocrine tumor (NET) producing PTH that presented with severe hypercalcemia and OFC. Surgical removal of the pulmonary tumor resulted in resolution of hypercalcemia. Immunocytochemical analysis of the tumor tissue revealed PTH-positive staining. Recovery was complicated by severe hypocalcemia due to hungry bone syndrome.

Discussion

To the best of our knowledge, this is the first documented case of a pulmonary NET causing OFC via PTH. We further describe the successful identification and resection of a rare NET and restoration of calcium homeostasis with aggressive calcium and vitamin D repletion.

Conclusion

Although a rare cause of severe hypercalcemia and OFC, ectopic tumoral production of PTH must be considered in the differential diagnosis. Furthermore, resection of these tumors secreting PTH can lead to a protracted and severe high risk of hungry bone syndrome, which requires aggressive treatment to maintain calcium homeostasis.

Blood-Brain Barrier Leakage: A New Biomarker in Transient Ischemic Attacks

Background and Purpose- The diagnosis of transient ischemic attack is challenging. Evidence of acute ischemia on MRI diffusion-weighted imaging is highly variable and confirmed in only about one-third of patients. This study investigated the significance of blood-brain barrier dysfunction (BBBD) mapping in patients with transient neurological deficits, as a diagnostic and prognostic biomarker required for risk stratification and stroke prevention. Methods- We used dynamic contrast-enhanced MRI to quantitatively map BBBD in a prospective cohort study of 57 patients diagnosed with transient ischemic attack/minor stroke and 50 healthy controls. Results- Brain volume with BBBD was significantly higher in patients compared with controls ( P=0.002). BBBD localization corresponded with the clinical presentation in 41 patients (72%) and was more extensive in patients with acute infarct on diffusion-weighted imaging ( P=0.05). Patients who developed new stroke during follow-up had a significantly greater BBBD at the initial presentation ( P=0.03) with a risk ratio of 5.35 for recurrent stroke. Conclusions- This is the first description of the extent and localization of BBBD in patients with transient ischemic attack/minor stroke. We propose BBBD mapping as a valuable tool for detection of subtle brain ischemia and a promising predictive biomarker required for risk stratification and stroke prevention.

Assessing neuronal density in peri-infarct cortex with PET: Effects of cortical topology and partial volume correction

The peri-infarct cortex (PIC) is the site of long-term physiologic changes after ischemic stroke. Traditional methods for delineating the peri-infarct gray matter (GM) have used a volumetric Euclidean distance metric to define its extent around the infarct. This metric has limitations in the case of cortical stroke, i.e., those where ischemia leads to infarction in the cortical GM, because the vascularization of the cerebral cortex follows the complex, folded topology of the cortical surface. Instead, we used a geodesic distance metric along the cortical surface to subdivide the PIC into equidistant rings emanating from the infarct border and compared this new approach to a Euclidean distance metric definition. This was done in 11 patients with [F-18]-Flumazenil ([18-F]-FMZ) positron emission tomography (PET) scans at 2 weeks post-stroke and at 6 month follow-up. FMZ is a PET radiotracer with specific binding to the alpha subunits of the type A γ-aminobutyric acid (GABAA) receptor. Additionally, we used partial-volume correction (PVC) of the PET images to compensate for potential cortical thinning and long-term neuronal loss in follow-up images. The difference in non-displaceable binding potential (BPND ) between the stroke unaffected and affected hemispheres was 35% larger in the geodesic versus the Euclidean peri-infarct models in initial PET images and 48% larger in follow-up PET images. The inter-hemispheric BPND difference was approximately 17-20% larger after PVC when compared to uncorrected PET images. PET studies of peri-infarct GM in cortical strokes should use a geodesic model and include PVC as a preprocessing step. Hum Brain Mapp 38:326-338, 2017. © 2016 Wiley Periodicals, Inc.

Non-biological determinants of paediatric bladder bowel dysfunction: A pilot study

OBJECTIVES

Children with bladder and bowel dysfunction (BBD) constitute a significant proportion of referrals at paediatric urology clinics worldwide, presenting with a wide range of symptom severity that may significantly affect quality of life. Non-biological factors may play a key role in triggering BBD severity, but these underpinning causes of BBD during childhood are still unknown. The aim of this study was to identify the effects of personal, family related and environmental variables on the severity of BBD symptoms in school-aged children.

STUDY DESIGN

A pilot, prospective, observational study was conducted on 53 children diagnosed with BBD, and their legal guardian(s), on their first referred visit to a paediatric BBD clinic led by nurse practitioners. Upon receiving consent, patients and their legal guardian(s) completed three study questionnaires, with the guidance of research coordinators. The first questionnaire was the Dysfunctional Voiding Scoring System (DVSS); the second, a three-part questionnaire used to collect demographic information and data on the patient, their family and environmental characteristics; and the third gathered a detailed history of the child's lifestyle regimen, focusing on their bowel and bladder function.

RESULTS

Most of the children were female (66%), with an average age of 8.35 years. Most children attended public schools (74%) and none reported failing a grade. The mean parental age was 41.4 years (SD = 4.9 years), 62% of the families had two children and 53% were Caucasian. The mean DVSS score for this sample was 9.9 (SD = 4.2, range 2-21). Daycare attendance, school problems and unplanned pregnancy showed statistically significant influences on the severity of BBD and were associated with higher DVSS scores according to the Table below.

CONCLUSIONS

Children with BBD attending urology outpatient clinics as new referrals had more severe symptoms when they were born from an unplanned pregnancy, attended daycare and/or had school problems. These findings suggest that interventions aimed at decreasing BBD severity, or preventing its onset in school-aged children, should focus on the environment surrounding them, specifically on the interaction between personal, familial and environmental factors. These factors seem to have an important effect on paediatric continence, as children grow and develop under numerous societal influences and social interactions.

Changes in callosal motor fiber integrity after subcortical stroke of the pyramidal tract

In the healthy brain, there are close correlations between task-related activation of the primary motor cortex (M1), the magnitude of interhemispheric inhibition, and microstructural properties of transcallosal fiber tracts. After subcortical stroke affecting the pyramidal tract (PT), an abnormal pattern of bilateral activity develops in M1. With this prospective longitudinal study, we aimed to determine whether a morphological correlate of poststroke disinhibition could be measured within 20 days and 6 months of PT stroke. Using diffusion tensor imaging with tractography, we delineated transcallosal motor fibers (CMF) in nine PT stroke patients, six patients with subcortical infarct not affecting the PT (NonPT) and six transient ischemic attack patients. We compared changes in CMF fractional anisotropy ratios (rFA) with rFA in a distinct bundle of callosal occipital fibers (COF). At the initial time point, there were no significant differences in rFA between groups and fiber bundles. At follow-up, PT-group rFA(CMF) was significantly lower than PT-group rFA(COF) and NonPT-group rFA(CMF). PT-group rFA(CMF) decreased over time and correlated with rFA of the PT (rFA(PT)) retrograde to the infarct at 6 months. Our data suggest a progressive degenerative transsynaptic effect of PT stroke on CMF, which could be a morphological correlate of transcallosal disinhibition.

Diffusion tensor imaging, permanent pyramidal tract damage, and outcome in subcortical stroke

BACKGROUND

Studies in chronic stroke patients suggest that diffusion tensor imaging (DTI) parameters of the pyramidal tract (PT) relate to residual motor function. We performed a prospective controlled study to evaluate if the DTI parameters tract volume (TV) and fractional anisotropy (FA) in patients with acute subcortical infarcts are correlated with permanent PT damage and clinical outcome after 6 months.

METHODS

We acquired DTI in 18 stroke patients with subcortical ischemic infarcts either affecting the PT (PT group, n = 12) or not (non-PT group, n = 6) and in 7 age- and risk factor-matched controls at median times of 12 and 180 days. The PT was isolated using tractography and tract volume ratios (R(TV)) and FA ratios (R(FA)) were calculated (affected tract/unaffected tract). Ratios were compared within and between groups at initial and follow-up time points, as well as in tract portions above and below the infarcts, and were correlated to Rivermead Motor Function Test (RMFT) scores.

RESULTS

Mean R(FA) and R(TV) of the PT group were smaller than those of both non-PT and control groups initially and at follow-up (p < 0.01). Tract portions above the infarct had lower R(TV) than below (p < 0.05). There was no significant change in R(FA) and R(TV) over time for the whole tract or tract portions. R(FA) and R(TV) both were highly correlated with initial and follow-up RMFT scores.

CONCLUSIONS

DTI parameters of PT integrity acquired within the first weeks after acute subcortical stroke measure permanent ischemic PT damage and are highly correlated with residual motor function in the acute and chronic stage.

The temporal dynamics of poststroke neuroinflammation: a longitudinal diffusion tensor imaging-guided PET study with 11C-PK11195 in acute subcortical stroke

Animal experiments suggest that 2 different types of activated microglia (AMG) cells occur in the brain after a stroke: local AMG in the area of the infarct and remote AMG, which occurs along affected fiber tracts. We used (11)C-PK11195 PET to image AMG in vivo after stroke in humans in a prospective longitudinal study to investigate the temporal dynamics of AMG and relate local and remote AMG activity to pyramidal tract (PT) damage using diffusion tensor imaging (DTI).

METHODS

Eighteen patients underwent DTI-MRI, (11)C-PK11195 PET, and behavioral testing within 2 wk and 6 mo of acute subcortical stroke. In 12 patients, the PT was affected by the stroke (PT group), and in 6 patients it was not (non-PT group). Standardized volumes of interest (VOIs) were placed along the PT at the level of the brain stem, semioval center, and infarct. Tracer uptake ratios (ipsilateral to contralateral) were calculated for each VOI and related to tract damage (measured as fractional anisotropy ratio) and clinical outcome. Six controls underwent the same protocol but only once.

RESULTS

In both patient groups, local AMG activity in the infarct was increased initially and significantly decreased over the follow-up period. In contrast, remote AMG was detected only in the PT group in the brain stem along the affected tract and persisted during follow-up. No AMG was observed retrograde to the lesion at any time. Remote AMG activity along the affected PT in the brain stem correlated with initial PT damage as measured by DTI in the same tract portion. Local AMG activity in the infarct correlated with anterograde PT damage only at follow-up. After controlling for PT damage, initial AMG activity in the brain stem showed a positive correlation with clinical outcome, whereas persisting AMG activity in the infarct tended to be negatively correlated.

CONCLUSION

DTI-guided (11)C-PK11195 PET in acute subcortical stroke demonstrates differential temporal dynamics of local and remote AMG. Activity of both types related to anterograde PT damage as measured by DTI and might contribute differently to clinical outcome.

Stroke Outcome in Those Over 80

Background and Purpose— The prevalence of stroke in elderly patients has been increasing in recent years. However, limited information is available about the burden of stroke in individuals over 80. We sought to evaluate differences in clinical outcomes in Canadians over 80 years old hospitalized for an acute ischemic stroke.

Methods— The authors conducted a multicenter cohort study including all hospital admissions for ischemic stroke identified from the Canadian Hospital Morbidity and Mortality Database from April 2003 to March 2004. The Hospital Morbidity and Mortality Database contains a national database that contains patient-level sociodemographic, diagnostic, procedural, and administrative information from across Canada. Multivariable analysis was performed using logistic regression. The primary outcome was 7-day case fatality and fatality at discharge. Secondary end points included intensive care unit admissions, medical complications, gender differences, length of hospital stay, and discharge disposition.

Results— We analyzed 26 676 patients with ischemic stroke admitted to 606 hospitals across Canada. Mean age (SD) was 74±13 years. Overall, 10 171 (38%) were aged 80 years or older. Case fatality at discharge was 5.7% (age <59), 8.6% (age 60 to 69), 13.4% (age 70 to 79), and 24.2% (age ≥80; P <0.001). Patients aged 80 and over were less likely to be admitted to the intensive care unit (7.7% versus 15.3%; P <0.001) and discharged to their prestroke residence (47.2% for those over 80 versus 61.6% for patients younger than 80; P <0.001). Median length of stay was longer in those over 80 (10 days versus 7 days; P <0.0001). In the multivariable analysis for the older group, admission to the intensive care unit, low socioeconomic status, and admission to a nonacademic institution were associated with increased fatality after adjusting for covariates.

Conclusions— Aging of the population is a growing reality in Western societies and this translates into an increasing demand on healthcare systems. In our study, patients with stroke over 80 had higher risk-adjusted fatality, longer hospitalization, and were less likely to be discharged to their original place of residence. Strategies need to be implemented to facilitate equal access to specialized stroke care for the elderly.

Fibromuscular dysplasia with carotid artery dissection presenting as an isolated hemianopsia

BACKGROUND

Internal carotid artery (ICA) dissection is a well-known cause of anterior circulation stroke, but its association with posterior circulation stroke has been less commonly reported. The latter situation can arise when there is persistent fetal circulation of the posterior cerebral artery and has, to our knowledge, never been reported in the setting of fibromuscular dysplasia (FMD) involving the ICA.

METHODS

A 52-year-old man awoke with severe headache and noted visual loss. Examination confirmed a congruous left homonymous hemianopsia. A head computed tomography scan revealed an acute right posterior parietal infarct. Carotid ultrasonography demonstrated complete occlusion of the right ICA. Conventional angiography confirmed this and was diagnostic of FMD with dissection. A right-sided persistent fetal circulation was also noted. Magnetic resonance imaging revealed right parietal and right occipital infarctions.

RESULTS

The patient received ASA and clopidogrel and his visual deficit resolved within days. One year later, he remained asymptomatic and there was no suggestion of FMD in other vascular beds.

CONCLUSIONS

Although infrequently reported, carotid disease, including dissection, can be responsible for posterior circulation infarcts. Cervical artery dissection can be related to underlying arteriopathies such as FMD, which must be differentiated from vasculitis and vasospasm.

Statin treatment and adherence to national cholesterol guidelines after ischemic stroke

BACKGROUND

National cholesterol guidelines have defined high vascular risk individuals as those who could potentially benefit most from statin therapy. The authors aimed to determine the rate of statin use, its predictors, and the achievement of national guideline target lipid goals among ischemic stroke survivors.

METHODS

The authors abstracted data from the Vitamin Intervention for Stroke Prevention (VISP) study database from the United States and Canada to incorporate into algorithms for initiating statin therapy according to the National Cholesterol Education Program (NCEP) guidelines for high-risk individuals. The authors applied these algorithms to all study subjects. Univariate as well as multivariate associations for target lipid levels and statin implementation were then evaluated utilizing pertinent demographic, clinical, and laboratory data.

RESULTS

Of 2,894 subjects in the analysis dataset, 38% were women; 71% were recruited in the United States and 29% in Canada. Of 769 high-risk subjects, 262 (34%) had a low-density lipoprotein (LDL) level > or =130 mg/dL and 124 of these (47%) were not on statin. Among those high-risk persons on statin treatment, only 42% had an LDL < or =100 mg/dL. Subjects in the overall cohort were more likely to be on a statin if they were treated in the United States or had a history of hypertension or coronary artery disease.

CONCLUSIONS

Approximately one out of three guideline-eligible high vascular risk ischemic stroke patients in this study had low-density lipoprotein cholesterol concentrations above qualifying levels for pharmacologic therapy, but half of these patients were not taking a statin, and of those receiving statin treatment, less than half were within recommended lipid goals.

Predictive value of soluble intercellular adhesion molecule-1 for risk of ischemic events in individuals with cerebrovascular disease

BACKGROUND AND PURPOSE

Cellular adhesion molecules may play a critical role in the inflammatory process leading to atherosclerosis. The purpose of this study was to determine whether soluble intercellular adhesion molecule-1 (sICAM-1) is a predictor of future ischemic events in high-risk individuals and also whether it is associated with carotid artery stenosis.

METHODS

We conducted a prospective study of sICAM-1 concentration in 3 groups: (1) subjects with recent (< 7 days) ischemic stroke or TIA, (2) asymptomatic subjects with carotid stenosis > or = 50% and (3) asymptomatic individuals with vascular risk factors. Subjects were followed for a minimum of 3 years. sICAM-1 levels were compared between the groups and correlated with the risk of ischemic events and the degree of carotid artery stenosis.

RESULTS

We studied 275 subjects. Mean sICAM-1 levels were significantly higher in those with recent ischemic stroke or TIA compared to those with risk factors alone. During follow-up, ischemic events occurred almost nine times more frequently in subjects in group 1 compared to group 3. sICAM-1 concentration was not predictive of future ischemic events (OR 1.001, 95% CI 0.998-1.004). There was no significant association between sICAM-1 concentration and carotid artery stenosis (OR 1.001, 95% CI 0.999-1.004).

CONCLUSIONS

Mean sICAM-1 levels were higher in subjects with recent cerebral ischemia. No association between sICAM-1 and carotid artery stenosis was observed. Neither baseline nor subsequent sICAM-1 levels were predictive of the risk of future ischemic events.

Soluble intercellular adhesion molecule-1 in patients with recent cerebral ischemic events

P46

Objective: To determine whether serum levels of soluble intercellular adhesion molecule-1 (sICAM) differ between individuals with recent acute ischemic stroke (AIS) or transient ischemic attack (TIA) and control subjects. Methods: sICAM levels were measured in patients with recent (≤ 7 days) AIS or TIA and in patients with asymptomatic carotid stenosis and control subjects. Demographic information was collected and all subjects underwent complete neurological evaluations, routine blood tests and baseline cervical ultrasonography. Subjects with either a qualifying AIS or TIA also underwent cranial CT. sICAM levels were compared between different patient groups and correlated with carotid stenosis in those with AIS or TIA using analysis of variance (ANOVA) and logistic regression. Results: sICAM levels were measured in 288 patients (48.6% males). Of these, 91 had either a recent AIS or TIA. There were 75 control subjects. The remainder (n=122) had an asymptomatic carotid stenosis. Mean follow-up for all patients was 25.1 months. Mean age and distribution of cardiovascular risk factors were similar across all groups of patients. Mean sICAM levels were higher in those with recent AIS or TIA than in control subjects but without quite reaching statistical significance (p=0.10). For those with either AIS or TIA, mean sICAM levels did not differ on repeat measurement nor did initial levels correlate with the degree of carotid stenosis homolateral to the side of the ischemic event. During follow-up, 30 patients overall, (10.4%), experienced a recurrent ischemic event (either TIA, AIS, myocardial infarction and/or vascular death). Patients with either AIS or TIA, experienced a higher recurrence rate (24.6%). Mean sICAM levels were higher in those patients with a recurrent ischemic event (375.9 ng/mL) than in those without (332.1 ng/mL). Conclusion: There was a trend for higher sICAM levels in patients with recent AIS or TIA compared with control subjects. In addition, higher initial sICAM levels were associated with an increased risk of recurrent ischemic events for all patients.

Isolated trigeminal neuropathy due to trigeminal nerve root hemorrhage

BACKGROUND

Isolated trigeminal neuropathy is uncommon; causes include trauma, inflammation, or neoplasm.

METHODS

We report a patient who fell and struck his head during a myocardial infarction, was treated with streptokinase, and developed symptoms and signs of an isolated trigeminal sensory neuropathy.

RESULTS

Imaging showed hemorrhage in the trigeminal nerve root; follow-up imaging showed resolution of the hemorrhage, but no underlying structural lesion.

CONCLUSION

A combination of head trauma plus thrombolysis resulted in an isolated trigeminal neuropathy.

CNP2 mRNA directs synthesis of both CNP1 and CNP2 polypeptides

The ribosome scanning model for translational initiation predicts that eukaryotic mRNAs should, as a rule, be monocistronic. However, cases have recently been described of eukaryotic mRNAs producing more than one protein through alternative translational initiation at several different AUG codons. The present work reports the occurrence of two translational start sites on the mRNA encoding isoform 2 of the myelin marker enzyme 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) in rat and mouse. We show that the CNP2 mRNA is able to direct synthesis of not only CNP2, but also CNP1 polypeptide. Immunoprecipitation experiments using a polyclonal antibody directed against CNP detect both CNP isoforms in tissues or cell lines expressing only the CNP2 transcript. Thus, the synthesis of CNP1 and CNP2 polypeptides must be encoded by the CNP2 transcript. In vitro translation of synthetic CNP2 mRNA demonstrates that both CNP isoforms are synthesized by initiation at different AUG codons. Furthermore, by introducing mutations to "switch off" translation from the second in-frame AUG codon in the CNP2 cDNA, and transfecting 293T cells with those constructs, we are able to correlate the production of CNP1 and CNP2 with different translational start sites. These results lead us to conclude that the CNP2 mRNA is able to produce both CNP1 and CNP2 polypeptides. This investigation has altered our understanding of the temporal expression of the CNP protein isoforms during development of the central nervous system (CNS).

Differential intracellular sorting of the myelin-associated glycoprotein isoforms

Myelin-associated glycoprotein (MAG), a myelin-specific protein, is expressed as two isoforms, designated as L-MAG and S-MAG. Both share identical extracellular and transmembrane domains but differ in their cytoplasmic domains. L-MAG is expressed earlier during myelination than S-MAG. These features, as well as others, suggest that the isoforms have different functions. To confirm this hypothesis, both isoforms were expressed transiently and stably in Madin-Darby canine kidney (MDCK) epithelial cells, and the localization of the isoforms was studied. In both transiently and stably transfected cells, L-MAG sorted primarily to the basolateral membrane. In single transfected cells, S-MAG sorted primarily to the apical membrane. When groups of adjacent cells became transiently transfected, S-MAG accumulated at areas of cell-cell contact within the basolateral membrane. In stably transfected cells S-MAG sorted to the basolateral membrane. The data suggest that L-MAG contains an invariable basolateral sorting signal, but that the sorting of S-MAG is dependent upon extrinsic factors, such as coexpression by adjacent (contacting) cells. As MDCK cells sort the MAG isoforms differently, these data support the hypothesis that the MAG isoforms do perform different functions.

Upper airway involvement in Parkinson's disease resulting in postoperative respiratory failure

A 71-yr-old man with a six-year history of Parkinson's disease (PD), Type II diabetes mellitus, myocardial infarction, and remote 20 pack-year smoking history, underwent an anterior resection of the rectum for carcinoma. Sixty hours later, the patient suffered a respiratory arrest; his antiparkinsonian medications had not been resumed. Preoperative flow-volume loops showed the characteristic saw-tooth pattern of PD indicating dysfunction of the striated muscle of the upper airway. Although postoperative respiratory distress was managed as lower airway obstruction, at the time of intubation there were no signs of lower airway pathology. Upper airway dysfunction and obstruction secondary to PD is thought to have been a contributing factor to the postoperative respiratory distress and failure. This case is presented to draw attention to the risk of upper airway dysfunction in Parkinson's Disease, especially with the withdrawal of antiparkinsonian medications.