Benefits of GLP-1 (Glucagon-Like Peptide 1) Receptor Agonists for Stroke Reduction in Type 2 Diabetes: A Call to Action for Neurologists

People living with diabetes are at higher risk for stroke and have a poorer prognosis following a stroke event than those without diabetes. Data from cardiovascular outcome trials and meta-analyses indicate that GLP-1RAs (glucagon-like peptide 1 receptor agonists) reduce the risk of stroke in individuals with type 2 diabetes. Accordingly, many guidelines now recommend the addition of GLP-1RAs to ongoing antihyperglycemic regimens to lower the risk of stroke in type 2 diabetes. The current work summarizes evidence supporting the use of GLP-1RAs for stroke reduction in people with type 2 diabetes and offers 2 new resources for neurologists who are considering GLP-1RAs for their patients-a list of frequently asked questions with evidence-based answers on safely initiating and managing GLP-1RAs, and a practical decision-making algorithm to assist in using GLP-1RAs as part of a stroke reduction strategy.

Deferral of Consent: Recent Lessons From Canadian Acute Stroke Trials

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Diagnosis of Transient Ischemic Attack: Sex-Specific Differences From a Retrospective Cohort Study

BACKGROUND AND PURPOSE

Research suggests that women and men may present with different transient ischemic attack (TIA) and stroke symptoms. We aimed to explore symptoms and features associated with a definite TIA/stroke diagnosis and whether those associations differed by sex.

METHODS

We completed a retrospective cohort study of patients referred to The Ottawa Hospital Stroke Prevention Clinic in 2015. Exploratory multinomial logistic regression was used to evaluate candidate variables associated with diagnosis and patient sex. Backwards elimination of the interaction terms with a significance level for staying in the model of 0.25 was used to arrive at a more parsimonious model.

RESULTS

Based on 1770 complete patient records, sex-specific differences were noted in TIA/stroke diagnosis based on features such as duration of event, suddenness of symptom onset, unilateral sensory loss, and pain.

CONCLUSIONS

This preliminary work identified sex-specific differences in the final diagnosis of TIA/stroke based on common presenting symptoms/features. More research is needed to understand if there are biases or sex-based differences in TIA/stroke manifestations and diagnosis.

Cohort Study of Features Used by Experts to Diagnose Transient Ischemic Attack

Background and Purpose

The diagnosis of transient ischemic attack (TIA) is largely dependent on a process of clinical decision-making that remains poorly characterized in the absence of a validated and accessible biomarker or imaging test. We performed a retrospective chart review to identify variables associated with a final neurologist diagnosis of TIA/stroke.

Methods

Records for all patients seen in The Ottawa Hospital's Stroke Prevention Clinic in 2015 were analyzed for patient and referral characteristics, features of the presenting neurological event, and final diagnosis by a stroke neurologist (classified as definite, possible, or definite not TIA/stroke). Multinomial logistic regression analysis with backward elimination was used to identify variables associated with the final diagnosis.

Results

Our inclusion criteria were met by 1894 patients. After backward elimination, 23 potentially important variables were identified, including monocular vision loss (odds ratio [OR]: 30.4, 95% confidence interval [CI]: 14.6-63.3), symptoms of sudden onset (OR: 28.3, 95% CI: 14.2-56.2), unilateral weakness affecting 2 or 3 of face, arm, or leg (OR: 17.7, 95% CI: 9.8-31.7), and homonymous hemianopia (OR: 16.6, 95% CI: 8.1-34.0).

Conclusions

Accurate diagnosis of TIA is essential to initiating appropriate secondary stroke prevention therapies. A focus on elements of the patient history most commonly associated with a final diagnosis of TIA/stroke may help to identify patients in greatest need of urgent SPC assessment and allow for the provision of effective and efficient stroke prevention services.

Timing of paediatric orchidopexy in universal healthcare systems: international administrative data cohort study

BACKGROUND

International guidelines in 2008 recommended orchidopexy for undescended testis at 6-12 months of age to reduce the risk of testicular cancer and infertility. Using administrative data from England, Finland, Ontario (Canada), Scotland and Sweden (with data from Victoria (Australia) and Iceland in supplementary analyses), the aim of this study was to investigate compliance with these guidelines and identify potential socioeconomic inequities in the timing of surgery before 1 and 3 years.

METHODS

All boys born in 2003-2011 with a diagnosis code of undescended testis and procedure codes indicating orchidopexy before their fifth birthday were identified from administrative health records. Trends in the proportion of orchidopexies performed before 1 and 3 years of age were investigated, as were socioeconomic inequities in adherence to the guidelines.

RESULTS

Across all jurisdictions, the proportion of orchidopexies occurring before the first birthday increased over the study period. By 2011, from 7·6 per cent (Sweden) to 27·9 per cent (Scotland) of boys had undergone orchidopexy by their first birthday and 71·5 per cent (Sweden) to 90·4 per cent (Scotland) by 3 years of age. There was limited evidence of socioeconomic inequities for orchidopexy before the introduction of guidelines (2008). Across all jurisdictions for boys born after 2008, there was consistent evidence of inequities in orchidopexy by the first birthday, favouring higher socioeconomic position. Absolute differences in these proportions between the highest and lowest socioeconomic groups ranged from 2·5 to 5·9 per cent across jurisdictions.

CONCLUSION

Consistent lack of adherence to the guidelines across jurisdictions questions whether the guidelines are appropriate.

P115 Subarachnoid haemorrhage with negative initial vascular imaging: a single unit experience

Objectives

To investigate the incidence of vascular abnormality and clinical outcomes in a group of patients presenting with spontaneous subarachnoid haemorrhage (SAH) and negative initial vascular investigation.

Design

Single centre prospective cohort study.

Subjects

All adult patients with SAH admitted to our unit over a 12 month period.

Methods

Prospective collection of data on secure electronic database. Information pertaining to gender, age, mode of initial and subsequent vascular investigations was acquired. Details regarding clinical outcomes at 30 days and complications were documented.

Results

118 consecutive patients with SAH were admitted to our unit over the 12 month study period. 37 patients had negative initial vascular imaging (37/118=31.4%). M:F=19:18, age range 26–76 years. 32 patients underwent a high quality CT angiogram as initial vascular investigation, 5 patients underwent catheter cerebral angiogram (DSA). The most common modality of further vascular imaging was DSA. 5 vascular abnormalities were detected on subsequent vascular imaging (5/37=13.5%). Hydrocephalus and vasospasm were the commonest complications. Clinical outcomes were very good; all patients had a GOS of 5 at 30 days.

Conclusions

Patients with SAH and negative initial vascular investigation are an important subset of patients with SAH. There is no uniformity in the type of subsequent vascular investigations selected. Our experience is consistent with previously published studies.

Abstract TP393: Sex Differences in Neurologist Diagnosis of Transient Ischemic Attack in Association With Presenting Symptoms

Effective management of Transient Ischemic Attack (TIA) and stroke hinges on accurate diagnosis. Research suggests that women and men present with different TIA/stroke symptoms, and those more commonly reported by women are often considered atypical, or benign. For this reason, TIA or stroke in women may be underdiagnosed and undertreated. Growing evidence that women are disproportionately affected by stroke underpins this study focused on neurologist diagnosis of stroke/TIA in association with presenting symptoms. A retrospective chart review was performed using data from the charts of all patients referred to The Ottawa Hospital Stroke Prevention Clinic in 2015 with a provisional diagnosis of TIA/stroke. Demographics, event characteristics, and final diagnosis were extracted from each chart. Multinomial logistic regression analysis with backwards elimination and a significance level staying in the model of α=0.15 was used to identify variables associated with a final diagnosis of definite TIA/stroke. A sub-analysis was completed for the final model by sex. Of the 1864 included patients, 932 (50%) were women. There were no significant differences in age or final diagnosis of definite TIA/stroke based on sex. Among patients reporting classic stroke symptoms such as unilateral weakness, aphasia, and amaurosis fugax both sexes demonstrated significantly higher odds of a final diagnosis of TIA/stroke; however the odds were higher for men than women. For example, men with unilateral weakness, aphasia or amaurosis fugax had an odds ratio (OR) of 32.7, 7.7, and 27.8 respectively of having a final diagnosis of TIA/stroke, whereas the OR for women was 10.9, 5.4, and 22.2 respectively, although the 95% confidence intervals overlapped. In contrast, women reporting homonymous hemianopsia or any combination of ataxia, diplopia, or vertigo had a higher odds than men of being diagnosed with TIA/stroke (OR 21 and 8.5 respectively for women and OR 11.4 and 5.1 respectively for men). The trend in differences noted for the odds of definite TIA/stroke diagnosis among men and women may imply that women are less likely to be diagnosed with TIA even when reporting classical symptoms. More research is needed to understand sex-based differences in the diagnosis of TIA/stroke.

How do neurologists diagnose transient ischemic attack: A systematic review

Background

Identifying and treating patients with transient ischemic attack is an effective means of preventing stroke. However, making this diagnosis can be challenging, and over a third of patients referred to stroke prevention clinic are ultimately found to have alternate diagnoses.

Aims

We performed a systematic review to determine how neurologists diagnose transient ischemic attack.

Summary of review

A systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using MEDLINE, Embase, and the Cochrane Library databases. Publications eligible for inclusion were those that included information on the demographic or clinical features neurologists use to diagnose transient ischemic attacks or transient ischemic attack–mimics. Of 1666 citations, 210 abstracts were selected for full-text screening and 80 publications were ultimately deemed eligible for inclusion. Neurologists were more likely to diagnose transient ischemic attack based on clinical features including negative symptoms or speech deficits. Patients with positive symptoms, altered level of consciousness, or the presence of nonfocal symptoms such as confusion or amnesia were more likely to be diagnosed with transient ischemic attack–mimic. Neurologists commonly include mode of onset (i.e. sudden versus gradual), recurrence of attacks, and localizability of symptoms to a distinct vascular territory in the diagnostic decision-making process. Transient ischemic attack diagnosis was more commonly associated with advanced age, preexisting hypertension, atrial fibrillation, and other vascular risk factors.

Conclusions

Neurologists rely on certain clinical and demographic features to distinguish transient ischemic attacks from mimics, which are not currently reflected in widely used risk scores. Clarifying how neurologists diagnose transient ischemic attack may help frontline clinicians to better select patients for referral to stroke prevention clinics.

Cancer, atrial fibrillation, and stroke

Cancer patients appear to be at increased risk for atrial fibrillation. Although surgery and chemotherapy exacerbate this risk, this association is observed even in the absence of any cancer-specific treatment. The underlying mechanism of this is likely multifactorial, but systemic inflammation and autonomic dysregulation are hypothesized to play critical roles. Cancer and atrial fibrillation are both independent risk factors for ischemic stroke; however, it is not clear whether this translates to an increased risk of stroke in patients with both comorbidities. As such, commonly used risk stratification tools including the CHADS2 score currently do not take cancer into account as a variable and it is possible that stroke risk is underestimated in this population. There is a paucity of data regarding anticoagulant choice in cancer patients with atrial fibrillation. Vitamin K antagonists are often preferred over direct oral anticoagulants; however, this may be changing in the near future as new trials specific to this patient population emerge.

The development and validation of a meta-tool for quality appraisal of public health evidence: Meta Quality Appraisal Tool (MetaQAT)

OBJECTIVES

Most quality appraisal tools were developed for clinical medicine and tend to be study-specific with a strong emphasis on risk of bias. In order to be more relevant to public health, an appropriate quality appraisal tool needs to be less reliant on the evidence hierarchy and consider practice applicability. Given the broad range of study designs used in public health, the objective of this study was to develop and validate a meta-tool that combines public health-focused principles of appraisal coupled with a set of design-specific companion tools.

STUDY DESIGN

Several design methods were used to develop and validate the tool including literature review, synthesis, and validation with a reference standard.

METHODS

A search of critical appraisal tools relevant to public health was conducted; core concepts were collated. The resulting framework was piloted during three feedback sessions with public health practitioners. Following subsequent revisions, the final meta-tool, the Meta Quality Appraisal Tool (MetaQAT), was then validated through a content analysis of appraisals conducted by two groups of experienced public health researchers (MetaQAT vs generic appraisal form).

RESULTS

The MetaQAT framework consists of four domains: relevancy, reliability, validity, and applicability. In addition, a companion tool was assembled from existing critical appraisal tools to provide study design-specific guidance on validity appraisal. Content analysis showed similar methodological and generalizability concerns were raised by both groups; however, the MetaQAT appraisers commented more extensively on applicability to public health practice.

CONCLUSIONS

Critical appraisal tools designed for clinical medicine have limitations for use in the context of public health. The meta-tool structure of the MetaQAT allows for rigorous appraisal, while allowing users to simultaneously appraise the multitude of study designs relevant to public health research and assess non-standard domains, such as applicability.

Impact of diabetes on healthcare costs in a population-based cohort: a cost analysis

AIMS

To estimate the healthcare costs attributable to diabetes in Ontario, Canada using a propensity-matched control design and health administrative data from the perspective of a single-payer healthcare system.

METHODS

Incident diabetes cases among adults in Ontario were identified from the Ontario Diabetes Database between 2004 and 2012 and matched 1:3 to control subjects without diabetes identified in health administrative databases on the basis of sociodemographics and propensity score. Using a comprehensive source of administrative databases, direct per-person costs (Canadian dollars 2012) were calculated. A cost analysis was performed to calculate the attributable costs of diabetes; i.e. the difference of costs between patients with diabetes and control subjects without diabetes.

RESULTS

The study sample included 699 042 incident diabetes cases. The costs attributable to diabetes were greatest in the year after diagnosis [C$3,785 (95% CI 3708, 3862) per person for women and C$3,826 (95% CI 3751, 3901) for men], increasing substantially for older age groups and patients who died during follow-up. After accounting for baseline comorbidities, attributable costs were primarily incurred through inpatient acute hospitalizations, physician visits and prescription medications and assistive devices.

CONCLUSIONS

The excess healthcare costs attributable to diabetes are substantial and pose a significant clinical and public health challenge. This burden is an important consideration for decision-makers, particularly given increasing concern over the sustainability of the healthcare system, aging population structure and increasing prevalence of diabetic risk factors, such as obesity.

Measurement of muon neutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV

We report a study of ν(μ) charged-current quasielastic events in the segmented scintillator inner tracker of the MINERvA experiment running in the NuMI neutrino beam at Fermilab. The events were selected by requiring a μ- and low calorimetric recoil energy separated from the interaction vertex. We measure the flux-averaged differential cross section, dσ/dQ², and study the low energy particle content of the final state. Deviations are found between the measured dσ/dQ² and the expectations of a model of independent nucleons in a relativistic Fermi gas. We also observe an excess of energy near the vertex consistent with multiple protons in the final state.

Measurement of muon antineutrino quasielastic scattering on a hydrocarbon target at Eν ~ 3.5 GeV

We have isolated ν(μ) charged-current quasielastic (QE) interactions occurring in the segmented scintillator tracking region of the MINERvA detector running in the NuMI neutrino beam at Fermilab. We measure the flux-averaged differential cross section, dσ/dQ², and compare to several theoretical models of QE scattering. Good agreement is obtained with a model where the nucleon axial mass, M(A), is set to 0.99 GeV/c² but the nucleon vector form factors are modified to account for the observed enhancement, relative to the free nucleon case, of the cross section for the exchange of transversely polarized photons in electron-nucleus scattering. Our data at higher Q² favor this interpretation over an alternative in which the axial mass is increased.

Structure and function of the perinucleolar compartment in cancer cells

The perinucleolar compartment (PNC) is a subnuclear body that forms in cancer cells. In vivo analyses using human tumor tissues demonstrate a close correlation between PNC prevalence and disease progress in colorectal carcinoma, and a high PNC prevalence is associated with poor patient outcome. These findings are consistent with previous observations in breast cancer and cancer cell lines in vitro. The PNC is composed of thick strands that form a filamental meshwork often extending into the nucleolus. Although it appears to be electron dense as observed by transmission electron microscopy (TEM), the actual density of the structure imaged by electron spectroscopy is much lower, similar to that of the interchromatin space, and is lined with ribonucleoproteins (RNPs). In situ detections show that the PNC is highly enriched with a subset of small RNAs of polymerase III (Pol III) origins and RNA-binding proteins primarily implicated in pre-mRNA processing. A novel gel-shifting approach demonstrates that the addition of PNC-associated RNAs into HeLa cell lysates increases the mobility of polypyrimidine tract-binding (PTB) protein in a native gel electrophoresis, suggesting an interaction between these RNAs and PTB proteins. On the basis of these and other findings, we propose a working model in which novel RNPs have a key role in regulating gene expression at the PNC in cancer cells.

Functional imaging of cognitive impairment in Parkinson's disease

Parkinson's disease (PD) is known by most persons to be a neurodegenerative disorder that affects one's motor skills. However, the disease is also characterized by the less recognized cognitive symptoms, including deficits in executive functioning, as well as mood and behavioral problems, which are just as disabling and distressing as the motor symptoms. Imaging methods such as positron emission tomography (PET) have recently enhanced our understanding of cognitive disturbances in PD, and are reviewed in the current article. Furthermore, insights gained from the use of specific radiotracers in the dopaminergic and cholinergic neurotransmitter systems are discussed, as well as findings from in vivo detection of amyloid-beta. We will also discuss the potential use of a metabolic covariance network as a biomarker in clinical trials for the objective assessment of cognitive dysfunction in PD.

Habits and rabbits

Word associations have traditionally been used in linguistic research as a means of accessing information about the organisation of the mental lexicon. A number of important studies have revealed differences in word association behaviour in the L1 and the L2, but have failed to find consistent behaviour patterns. The study reported here suggests that this failure might be due to two factors: the choice of stimulus words and the categorisation of responses, which impose artificial constraints on both association behaviour and the exploration of response types. In order to move the investigation of L2 word associations forward, this study compares native speaker responses to a specific set of stimuli with those of advanced non-native speakers. The types of association response made by each group of subjects are investigated by means of a retrospective interview, and patterns in response types are mapped. This results in a new method of categorising word association responses, and provides more precise insight into the differences between L1 and L2 association patterns.

Subcellular localization and characterization of chorismate synthase in the apicomplexan Plasmodium falciparum

The resurgence of drug-resistant apicomplexa, in particular Plasmodium falciparum, the most fatal human malarial parasite, has focused attention on the recent discovery of the shikimate pathway in these organisms, as it may provide the urgently required, novel drug targets resulting from the absence of this pathway in mammals. The direction of a parasiticidal drug design programme obviously requires knowledge of the subcellular localization and indeed full characterization of the possible enzyme targets. Here, we report the cloning and characterization of chorismate synthase from P. falciparum and present the first biochemical and immunological studies of an enzyme of the shikimate pathway from an apicomplexan parasite. We show that this chorismate synthase does not possess an intrinsic flavin reductase activity and is therefore monofunctional like the plant and bacterial chorismate synthases. Highest immunological cross-reactivity was found with a plant chorismate synthase. However, in contrast to the plant enzyme, which is located to the plastid, P. falciparum chorismate synthase is found in the parasite cytosol, akin to the fungal enzymes that possess an intrinsic flavin reductase activity (i.e. are bifunctional). Thus, P. falciparum chorismate synthase has a combination of properties that distinguishes it from other described chorismate synthases.

Antiproliferative actions of inhalational anesthetics: comparisons to the valproate teratogen

The antiproliferative potential of the volatile anesthetics isoflurane, enflurane and sevoflurane was determined and compared to the valproate teratogen. The in vitro system employed, a G1 phase proliferative arrest endpoint in C6 glioma, has served previously to discriminate agents with known teratogenic potential in vivo. Based on estimated IC(50) values that were within twice the estimated minimum aveolar concentration value, the rank antiproliferative potency of the inhalational anesthetics employed was isoflurane=enflurane>>sevoflurane. Flow cytometric analysis of growth-arrested cell populations failed to reveal specific accumulation in any cell cycle phase and the lack of a G1 phase-specific effect was confirmed by the absence of a transient, time-dependent sialylation event in synchronized cells. The antiproliferative mechanism of volatile anesthetics, and valproate, was mediated at hydrophobic binding sites, as increasing the hydration sphere of the drug-micelle complex, using the hygroscopic qualities of the dimethylsulfoxide vehicle, completely reversed this effect. Our findings suggest inhalational anesthetics lack the specific in vitro characteristics of the valproate teratogen.

Determinants of home health visit length: results of a multisite prospective study

OBJECTIVES

The authors (1) compare visit length across four categories of skilled nursing home health visits which reflect recent changes in home health casemix-AIDS-related, hospice/terminal (HT), intravenous (IV) therapy, and maternal and child health (MCH)-with general adult medical/surgical (MS) visits and (2) identify factors influencing visit length.

METHODS

The study sites were 12 nonproprietary Massachusetts home health agencies (HHAs). Staff nurses collected data concurrently on a sample of visits they provided between December 1, 1992 and November 30, 1993. The visits were stratified by agency, time of year, and visit category. The authors used analysis of variance to test for significant differences across visit categories in Home Length of Visit (the number of minutes between when the nurse entered and left the home) (HLOV). The authors used multivariate regression analysis to develop models identifying determinants of HLOV and adjusted R2 to measure the explanatory power of partial models.

RESULTS

In univariate analysis, the categories differed significantly from each other in length (P < 0.0001). HT visits were the longest (median visit length = 60, 80, and 59 minutes for HT Only visits, visits in both the HT and AIDS categories (HT/AIDS), and HT/IV visits, respectively). MS visits were the shortest (median = 30 minutes). The remaining categories were intermediate in length (medians = 37 to 50 minutes). Almost half the variability in HLOV was explained by the full multivariate regression model, which includes all independent variables (adjusted R2 = .4486; P < 0.0001). Visit characteristics alone in a partial model explained 18% of the variability in HLOV. Three other variable sub-groups-agency, client characteristics, and nursing workload-each explained about 15% of the variability in HLOV. Nursing activities performed during the visit explained 11%; several of these related to teaching, education, or assessment.

CONCLUSIONS

Accurate reimbursement reflecting casemix differences is important to protect the teaching, education, and assessment functions of nurses; measure nurse productivity and allocate caseloads; maintain access to services for clients with greater needs; and avoid creating economic disincentives to the agencies that serve them. Payers formulating prospective payment systems can adjust per visit reimbursement rates to reflect differences in visit length by category and incorporate functional limitations, clinical instability, and case coordination as classification variables. Developers of home health casemix systems can use factor analysis to improve the robustness of multivariate models and include nursing workload in predicting visit length. Home health agencies measuring productivity and caseload across complex client populations can classify visits into three groups-MS; HT; and AIDS, IV, and MCH-or use the regression results to develop more refined predictors of visit length and nursing caseload.

Pregnancy and delivery in a patient with recent peripartum cardiomyopathy

We present a case of successful pregnancy and delivery in a patient with peripartum cardiomyopathy who conceived only 3 months after a vaginal delivery complicated by peripartum cardiomyopathy. Following the onset of labor, an arterial pressure catheter and pulmonary artery catheter were placed. A combined epidural spinal technique was performed without difficulty for labor analgesia. After a few hours of labor, the fetal heart rate tracing revealed repetitive variable decelerations, and a decision was made to proceed with operative delivery. The mother's hemodynamic changes are presented, and the specifics of the anesthetic care are outlined.

A model of blast overpressure injury to the lung

Despite decades of animal experiments, data on blast injury to the lung cover only a limited number of circumstances and are in a fragmented form. This paper develops a mathematical model of the chest wall dynamics and the subsequent generation of strong pressure waves within the lung, which have been hypothesized as the mediator of injury. The model has been compared to an extensive database of observed pathologies from animal tests. The incidence of injury and lethality is found to follow a log-normal correlation with the computed total energy in these waves and, when the energy is normalized by the lung volume, the lethality correlation applies to all large animal species. Small animals also correlate with the normalized energy, but at a different value, and it is speculated that structural differences, other than lung volume, may be involved. This relatively simple model allows the potential for blast injury to the lung to be determined from measured or computed pressure traces without additional animal testing. Improved occupational exposure criteria should follow from this methodology.

Linkage, evolution, and expression of the rat apolipoprotein A-I, C-III, and A-IV genes

The genes coding for three of the proteins of the lipid transport system, apolipoproteins A-I (apoA-I), C-III (apoC-III), and A-IV (apoA-IV), are closely linked and tandemly organized as a multigene family in the human genome. The evolution of this multigene family was studied by cloning and extensive restriction mapping analysis of an approximately 20-kilobase genomic DNA fragment containing the rat apoA-I gene. Low stringency hybridization blotting analysis of this DNA fragment using human apoC-III and apoA-IV cDNA probes revealed that the apoA-I, apoC-III, and apoA-IV genes are also closely linked and tandemly organized in the rat genome. Complete characterization of the rat apoA-I, apoC-III, and apoA-IV genes showed that their relative location, size, direction of transcription, and intron-exon organization are remarkably similar to those of the corresponding human genes. The relative steady state apoA-I, apoC-III, and apoA-IV mRNA levels in various rat tissues were determined by quantitative dot blot hybridization of tissue total RNA using the corresponding gene probes. Adult liver and intestine, but not colon, brain, spleen, muscle, heart, lung, and kidney, contain apoA-I, apoC-III, and apoA-IV mRNAs. Fetal liver and intestine contain apoA-I but not apoC-III or apoA-IV mRNAs. During neonatal development the liver contains apoA-I and apoC-III but not apoA-IV while the intestine contains apoA-I, apoC-III, and substantial amounts of apoA-IV mRNAs. In adulthood and during aging both liver and intestine contain all three apoA-I, apoC-III, and apoA-IV mRNAs. These results indicate that the apolipoprotein A-I/C-III/A-IV multigene family was established before mammalian radiation and suggest that these genes are similarly organized in the genomes of all mammals. In addition, these results indicate that expression of the rat apoA-I, apoC-III, and apoA-IV genes is liver- and intestine-specific and regulated by fetal-, neonatal-, and aging-related factors.

Responses to leukotriene C4 in the perfused rat lung

The isolated rat lung was used to study both the effect of leukotriene C4 on pulmonary perfusion pressure and the synthesis and release of cyclooxygenase products in the pulmonary circulation. A cell-free perfusate was passed only once through the pulmonary circulation or was recirculated. During single transit, leukotriene C4 produced dose-dependent increases in pulmonary perfusion pressure that were abolished by FPL-55712, a leukotriene receptor antagonist, but were not altered significantly by indomethacin. The duration of the pulmonary pressor response to leukotriene C4 was markedly prolonged during recirculation compared to single transit. Leukotriene C4 also induced dose-dependent increases in effluent levels of 6-keto-prostaglandin F1 alpha and thromboxane B2 that were attenuated by indomethacin or FPL-55712 pretreatment. We conclude that leukotriene C4 directly constricts the pulmonary vasculature independent of cyclooxygenase products, is not rapidly degraded by the pulmonary circulation and stimulates the release of cyclooxygenase products in the pulmonary circulation that can be attenuated by pretreatment with indomethacin or FPL-55712.

Quantitative criteria for prediction of the results after displaced fracture of the ankle

In a series of 146 displaced ankle fractures, the effects of age, sex, side of injury, mechanism of injury, severity as determined by the Lauge-Hansen classification, type of injury (open or closed), open or closed treatment, and internal fixation of one or both malleoli were analyzed using subjective, objective, and radiographic parameters. Statistically significant prognostic features were identified and a prognostic scale was developed using multiple linear-regression analysis. The significant parameters were age, adequacy of the post-reduction positions of the medial and lateral malleoli, and completeness of the restoration of the deltoid ligament and distal tibiofibular syndesmosis. Open reduction proved superior to closed reduction, and in bimalleolar fractures open reduction of both malleoli was better than fixing only the medial side. Using the data on the first 109 fractures, a multiple linear-regression equation was formulated and used to predict the outcomes of the last thirty-seven fractures in the study. The accuracy of the predictions in them was 81 per cent.

The corpus cavernosum intercommunicating venous drainage system

A series of cavernosograms were used to study the corpus cavernosum superficial and deep dorsal venous system. Within this drainage system exists an intricate circumflex venous interconnective network of vessels. In addition, each corpus cavernosum intercommunicates with its opposite corpus cavernosum through median septal apertures. The cavernosum venous system, unlike the venous drainage from the glans penis, delays venous drainage and in doing so assists in maintaining erections.