Histopathological diagnosis and surgical complications following bilateral anal sacculectomy for the treatment of unilateral canine apocrine gland anal sac adenocarcinoma: 35 cases (2019-2023)

OBJECTIVES

To report the histopathological diagnosis of both anal sacs in dogs undergoing bilateral anal sacculectomy for the treatment of unilateral apocrine gland anal sac adenocarcinoma and to compare the surgical complication rate associated with this procedure in this population with previously published literature.

MATERIALS AND METHODS

Records were retrospectively reviewed for dogs that underwent bilateral anal sacculectomy for the treatment of apparently unilateral apocrine gland anal sac adenocarcinoma, at a single institute between 2019 and 2023. Clinical staging, surgical treatment, histological findings, intra- and postoperative complications were evaluated.

RESULTS

Thirty-five dogs were included. Only five of 35 (14%) dogs were found to have histologically normal contralateral anal sacs. Non-neoplastic anal sac disease was found in 23 of 35 (66%) dogs and bilateral apocrine gland anal sac adenocarcinoma was seen in seven of 35 (20%) dogs. None of the dogs diagnosed with bilateral neoplasia had evidence of bilateral neoplasia before surgery despite a thorough work-up. Complications attributable to the primary tumour removal were seen in 9% of dogs intraoperatively and 14% of dogs postoperatively, commonly tumour capsule disruption and surgical site infection, respectively.

CLINICAL SIGNIFICANCE

Bilateral anal sac disease was diagnosed histologically in the majority of presumed normal anal sacs, with 20% of cases being found to have bilateral apocrine gland anal sac adenocarcinoma. The surgical complication rates of this cohort were comparable to those reported for unilateral anal sacculectomy alone. These findings promote and encourage the use of bilateral anal sacculectomy in cases of suspected unilateral anal sac neoplasia.

Performance evaluation of a non-invasive one-step multiplex RT-qPCR assay for detection of SARS-CoV-2 direct from saliva

Polymerase chain reaction (PCR) has proven to be the gold-standard for SARS-CoV-2 detection in clinical settings. The most common approaches rely on nasopharyngeal specimens obtained from swabs, followed by RNA extraction, reverse transcription and quantitative PCR. Although swab-based PCR is sensitive, swabbing is invasive and unpleasant to administer, reducing patient compliance for regular testing and resulting in an increased risk of improper sampling. To overcome these obstacles, we developed a non-invasive one-step RT-qPCR assay performed directly on saliva specimens. The University of Nottingham Asymptomatic Testing Service protocol simplifies sample collection and bypasses the need for RNA extraction, or additives, thus helping to encourage more regular testing and reducing processing time and costs. We have evaluated the assay against the performance criteria specified by the UK regulatory bodies and attained accreditation (BS EN ISO/IEC 17,025:2017) for SARS-CoV-2 diagnostic testing by the United Kingdom Accreditation Service. We observed a sensitivity of 1 viral copy per microlitre of saliva, and demonstrated a concordance of > 99.4% between our results and those of other accredited testing facilities. We concluded that saliva is a stable medium that allows for a highly precise, repeatable, and robust testing method.

Comparative epigenetic analysis of tumour initiating cells and syngeneic EPSC-derived neural stem cells in glioblastoma

Epigenetic mechanisms which play an essential role in normal developmental processes, such as self-renewal and fate specification of neural stem cells (NSC) are also responsible for some of the changes in the glioblastoma (GBM) genome. Here we develop a strategy to compare the epigenetic and transcriptional make-up of primary GBM cells (GIC) with patient-matched expanded potential stem cell (EPSC)-derived NSC (iNSC). Using a comparative analysis of the transcriptome of syngeneic GIC/iNSC pairs, we identify a glycosaminoglycan (GAG)-mediated mechanism of recruitment of regulatory T cells (Tregs) in GBM. Integrated analysis of the transcriptome and DNA methylome of GBM cells identifies druggable target genes and patient-specific prediction of drug response in primary GIC cultures, which is validated in 3D and in vivo models. Taken together, we provide a proof of principle that this experimental pipeline has the potential to identify patient-specific disease mechanisms and druggable targets in GBM.

Comparative effects of viral-transport-medium heat inactivation upon downstream SARS-CoV-2 detection in patient samples

Introduction

The COVID-19 pandemic, which began in 2020 is testing economic resilience and surge capacity of healthcare providers worldwide. At the time of writing, positive detection of the SARS-CoV-2 virus remains the only method for diagnosing COVID-19 infection. Rapid upscaling of national SARS-CoV-2 genome testing presented challenges: (1) Unpredictable supply chains of reagents and kits for virus inactivation, RNA extraction and PCR-detection of viral genomes. (2) Rapid time to result of <24 h is required in order to facilitate timely infection control measures.

Hypothesis

Extraction-free sample processing would impact commercially available SARS-CoV-2 genome detection methods.

Aim

We evaluated whether alternative commercially available kits provided sensitivity and accuracy of SARS-CoV-2 genome detection comparable to those used by regional National Healthcare Services (NHS).

Methodology

We tested several detection methods and tested whether detection was altered by heat inactivation, an approach for rapid one-step viral inactivation and RNA extraction without chemicals or kits.

Results

Using purified RNA, we found the CerTest VIASURE kit to be comparable to the Altona RealStar system currently in use, and further showed that both diagnostic kits performed similarly in the BioRad CFX96 and Roche LightCycler 480 II machines. Additionally, both kits were comparable to a third alternative using a combination of Quantabio qScript one-step Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) mix and Centre for Disease Control and Prevention (CDC)-accredited N1 and N2 primer/probes when looking specifically at borderline samples. Importantly, when using the kits in an extraction-free protocol, following heat inactivation, we saw differing results, with the combined Quantabio-CDC assay showing superior accuracy and sensitivity. In particular, detection using the CDC N2 probe following the extraction-free protocol was highly correlated to results generated with the same probe following RNA extraction and reported clinically (n=127; R²=0.9259).

Conclusion

Our results demonstrate that sample treatment can greatly affect the downstream performance of SARS-CoV-2 diagnostic kits, with varying impact depending on the kit. We also showed that one-step heat-inactivation methods could reduce time from swab receipt to outcome of test result. Combined, these findings present alternatives to the protocols in use and can serve to alleviate any arising supply-chain issues at different points in the workflow, whilst accelerating testing, and reducing cost and environmental impact.

Preparation of a User-Defined Peptide Gel for Controlled 3D Culture Models of Cancer and Disease

There is a growing awareness that cells grown in 3D better model in vivo behavior than those grown in 2D. In this protocol, we describe a simple and tunable 3D hydrogel, suitable for culturing cells and tissue in a setting that matches their native environment. This is particularly important for researchers investigating the initiation, growth, and treatment of cancer where the interaction between cells and their local extracellular matrix is a fundamental part of the model. Moving to 3D culture can be challenging and is often associated with a lack of reproducibility due to high batch-to-batch variation in animal-derived 3D culture matrices. Similarly, handling issues can limit the usefulness of synthetic hydrogels. In response to this need, we have optimized a simple self-assembling peptide gel, to enable the culture of relevant cell line models of cancer and disease, as well as patient-derived tissue/cells. The gel itself is free from matrix components, apart from those added during encapsulation or deposited into the gel by the encapsulated cells. The mechanical properties of the hydrogels can also be altered independent of matrix addition. It, therefore, acts as a 'blank slate' allowing researchers to build a 3D culture environment that reflects the target tissue of interest and to dissect the influences of mechanical forces and/or biochemical control of cell behavior independently.

Peptide gels of fully-defined composition and mechanics for probing cell-cell and cell-matrix interactions in vitro

Current materials used for in vitro 3D cell culture are often limited by their poor similarity to human tissue, batch-to-batch variability and complexity of composition and manufacture. Here, we present a "blank slate" culture environment based on a self-assembling peptide gel free from matrix motifs. The gel can be customised by incorporating matrix components selected to match the target tissue, with independent control of mechanical properties. Therefore the matrix components are restricted to those specifically added, or those synthesised by encapsulated cells. The flexible 3D culture platform provides full control over biochemical and physical properties, allowing the impact of biochemical composition and tissue mechanics to be separately evaluated in vitro. Here, we demonstrate that the peptide gels support the growth of a range of cells including human induced pluripotent stem cells and human cancer cell lines. Furthermore, we present proof-of-concept that the peptide gels can be used to build disease-relevant models. Controlling the peptide gelator concentration allows peptide gel stiffness to be matched to normal breast (<1 kPa) or breast tumour tissue (>1 kPa), with higher stiffness favouring the viability of breast cancer cells over normal breast cells. In parallel, the peptide gels may be modified with matrix components relevant to human breast, such as collagen I and hyaluronan. The choice and concentration of these additions affect the size, shape and organisation of breast epithelial cell structures formed in co-culture with fibroblasts. This system therefore provides a means of unravelling the individual influences of matrix, mechanical properties and cell-cell interactions in cancer and other diseases.

Perceptions of success of a local UK public health collaborative†

Summary

Successful public health initiatives require multi-sector collaboration. AVONet was a UK collaborative developed to provide evidence-based strategies for active ageing. This study explored the success of AVONet in the achievement of its objectives as perceived by all partners. A convergent parallel mixed-methods design was employed, utilizing a quantitative survey and qualitative semi-structured interviews. Data collection was undertaken in September 2010, 18 months after establishing the collaborative and 6 months after funding had ceased. AVONet partners (n = 24) completed a 27-item survey. A sub-sample of four academics and four practitioners participated in semi-structured interviews. Quantitative and qualitative comparisons were made between academics' and practitioners' perceptions of success, potential for sustainability and satisfaction with structure and relationships. Participants perceived the AVONet collaborative positively. Significant between-group (academic v practitioner) differences in survey responses were observed for success (U = 19.5; p = 0.003) and structure (U = 125.5; p = 0.001). Strong positive correlations were observed between success and structure and balance between information transfer and exchange (r = 0.756; p < 0.001). Interviews confirmed positive perceptions and perceived importance of the collaborative and highlighted the need for further integration and tangible outcomes for practitioners. Suggestions to enhance sustainability were provided, such as smaller working groups and local council-led governance. Perceived success in building a multi-sectoral collaborative can be achieved during a 10-month period, despite differing needs of contributors. For collaboratives developed as a result of external funding aimed primarily at facilitating research, involvement of practitioners at an early stage may help set more comprehensive goals, supportive communication strategies, and increase potential for sustainability.

The binding of micellar lipids to chitosan

The lipid binding capacity of chitosan (partially deacetylated chitin) was determinined with respect to micellar solutions of bile salts, dodecyl sulfate, natural ox bile and an artificial mixed microemulsion. The stoichiometry was determined following the separation of the solid phase by filtration or centrifugation. The major variables in the extent of binding were the pH and ionic strength, suggesting that the interactions are mainly of ionic nature. It is noteworthy that under optimal conditions chitosan could bind, i.e., coprecipitate, with 4-5 times of its weight with all the lipid aggregates tested. These results have a bearing on the nutritional and pharmacological applications of chitosan. The analyses of the components from the precipitates with microemulsion and ox bile show a significant selectivily of binding caused by hydrophobic interactions.

Managing the screen-viewing behaviours of children aged 5-6 years: a qualitative analysis of parental strategies

OBJECTIVES

The present study used qualitative methods to: (1) examine the strategies that were used by parents of children aged 5-6 years to manage screen viewing; (2) identify key factors that affect the implementation of the strategies and (3) develop suggestions for future intervention content.

DESIGN

Telephone interviews were conducted with parents of children aged 5-6 years participating in a larger study. Interviews were transcribed verbatim and analysed using an inductive and deductive content analysis. Coding and theme generation was iterative and refined throughout.

SETTING

Parents were recruited through 57 primary schools located in the greater Bristol area (UK).

PARTICIPANTS

53 parents of children aged 5-6 years.

RESULTS

Parents reported that for many children, screen viewing was a highly desirable behaviour that was difficult to manage, and that parents used the provision of screen viewing as a tool for reward and/or punishment. Parents managed screen viewing by setting limits in relation to daily events such as meals, before and after school, and bedtime. Screen-viewing rules were often altered depending on parental preferences and tasks. Inconsistent messaging within and between parents represented a source of conflict at times. Potential strategies to facilitate reducing screen viewing were identified, including setting screen-viewing limits in relation to specific events, collaborative rule setting, monitoring that involves mothers, fathers and the child, developing a family-specific set of alternative activities to screen viewing and developing a child's ability to self-monitor their own screen viewing.

CONCLUSIONS

Managing screen viewing is a challenge for many parents and can often cause tension in the home. The data presented in this paper provide key suggestions of new approaches that could be incorporated into behaviour change programmes to reduce child screen viewing.

The influence of friends and siblings on the physical activity and screen viewing behaviours of children aged 5-6 years: a qualitative analysis of parent interviews

OBJECTIVES

The present study uses qualitative data to explore parental perceptions of how their young child's screen viewing and physical activity behaviours are influenced by their child's friends and siblings.

DESIGN

Telephone interviews were conducted with parents of year 1 children (age 5-6 years). Interviews considered parental views on a variety of issues related to their child's screen viewing and physical activity behaviours, including the influence that their child's friends and siblings have over such behaviours. Interviews were transcribed verbatim and analysed using deductive content analysis. Data were organised using a categorisation matrix developed by the research team. Coding and theme generation was iterative and refined throughout. Data were entered into and coded within N-Vivo.

SETTING

Parents were recruited through 57 primary schools located in Bristol and the surrounding area that took part in the B-ProAct1v study.

PARTICIPANTS

Fifty-three parents of children aged 5-6 years.

RESULTS

Parents believe that their child's screen viewing and physical activity behaviours are influenced by their child's siblings and friends. Friends are considered to have a greater influence over the structured physical activities a child asks to participate in, whereas the influence of siblings is more strongly perceived over informal and spontaneous physical activities. In terms of screen viewing, parents suggest that their child's friends can heavily influence the content their child wishes to consume, however, siblings have a more direct and tangible influence over what a child watches.

CONCLUSIONS

Friends and siblings influence young children's physical activity and screen viewing behaviours. Child-focused physical activity and screen viewing interventions should consider the important influence that siblings and friends have over these behaviours.

Dietary changes and associations with metabolic improvements in adults with type 2 diabetes during a patient-centred dietary intervention: an exploratory analysis

OBJECTIVES

Describe dietary intake of participants enrolled in a non-prescriptive dietary intervention and dietary changes at 6 months and explore whether these changes had a role in observed improvements in glycated haemoglobin (HbA1c), weight, lipids and blood pressure.

DESIGN

Secondary analysis of data from the Early ACTivity in Diabetes randomised controlled trial.

PARTICIPANTS

262 patients with newly diagnosed type 2 diabetes randomised to the dietary intervention.

OUTCOMES AND ANALYSIS

Changes in energy intake, macronutrients, fibre and alcohol and in weight, waist circumference, lipids, HbA1c and blood pressure at baseline and 6 months. Multivariate models were used to examine associations between dietary changes and metabolic variables.

RESULTS

Men reported reducing mean energy intake from 1903±462 kcal to 1685 kcal±439 kcal (p<0.001), increasing carbohydrate intake from 42.4±6.6% to 43.8±6.6% (p=0.002) and reducing median alcohol intake from 13 (0-27) g to 5 (0-18) g (p<0.001). Women reported reducing mean energy intake from 1582±379 kcal to 1459±326 kcal (p<0.001) with no change to macronutrient distribution and alcohol. Fibre intake was maintained. In men (n=148), weak and clinically insignificant associations were found between increased carbohydrates and reduction in HbA1c (β=-0.003 (-0.006, -0.001); p=0.009), increased fibre and reduction in total cholesterol (β=-0.023 (-0.044, -0.002); p=0.033), decreased total fat and reduction in low-density lipoprotein (LDL)-cholesterol (β=0.024 (0.006, 0.001); p=0.011), and decreased alcohol and reduction in diastolic blood pressure (β=0.276 (0.055, 0.497); p=0.015). In women (n=75), associations were found between a decrease in transfats and reductions in waist circumference (β=-0.029 (0.006, 0.052); p=0.015), total cholesterol (β=0.399 (0.028, 0.770); p=0.036) and LDL cholesterol (β=0.365 (0.042, 0.668); p=0.028).

CONCLUSIONS

Clinically important metabolic improvements observed in a patient-centred dietary intervention were not explained by changes in macronutrients. However, a non-prescriptive approach may promote a reduction in total energy intake while maintaining fibre consumption.

TRIAL REGISTRATION NUMBER

The Early ACTID trial number ISRCTN92162869.

Long-term cognitive impairment after critical illness

BACKGROUND

Survivors of critical illness often have a prolonged and disabling form of cognitive impairment that remains inadequately characterized.

METHODS

We enrolled adults with respiratory failure or shock in the medical or surgical intensive care unit (ICU), evaluated them for in-hospital delirium, and assessed global cognition and executive function 3 and 12 months after discharge with the use of the Repeatable Battery for the Assessment of Neuropsychological Status (population age-adjusted mean [±SD] score, 100±15, with lower values indicating worse global cognition) and the Trail Making Test, Part B (population age-, sex-, and education-adjusted mean score, 50±10, with lower scores indicating worse executive function). Associations of the duration of delirium and the use of sedative or analgesic agents with the outcomes were assessed with the use of linear regression, with adjustment for potential confounders.

RESULTS

Of the 821 patients enrolled, 6% had cognitive impairment at baseline, and delirium developed in 74% during the hospital stay. At 3 months, 40% of the patients had global cognition scores that were 1.5 SD below the population means (similar to scores for patients with moderate traumatic brain injury), and 26% had scores 2 SD below the population means (similar to scores for patients with mild Alzheimer's disease). Deficits occurred in both older and younger patients and persisted, with 34% and 24% of all patients with assessments at 12 months that were similar to scores for patients with moderate traumatic brain injury and scores for patients with mild Alzheimer's disease, respectively. A longer duration of delirium was independently associated with worse global cognition at 3 and 12 months (P=0.001 and P=0.04, respectively) and worse executive function at 3 and 12 months (P=0.004 and P=0.007, respectively). Use of sedative or analgesic medications was not consistently associated with cognitive impairment at 3 and 12 months.

CONCLUSIONS

Patients in medical and surgical ICUs are at high risk for long-term cognitive impairment. A longer duration of delirium in the hospital was associated with worse global cognition and executive function scores at 3 and 12 months. (Funded by the National Institutes of Health and others; BRAIN-ICU ClinicalTrials.gov number, NCT00392795.).

HPA-axis function, symptoms, and medication exposure in youths at clinical high risk for psychosis

AIM

Increased basal cortisol secretion has been associated with heightened clinical risk for psychosis, and among at-risk individuals, has been variably related to positive and mood symptoms, as well as clinical outcome.

METHODS

Basal salivary cortisol secretion was assessed in 33 patients at clinical high risk (CHR) for psychosis (21 medication-free and 12 taking a serotonin reuptake inhibitor and/or atypical antipsychotic), and 13 healthy controls. Among the CHR patients, we also examined associations of basal salivary cortisol with symptoms (positive, negative, mood, stress sensitivity) and clinical outcome.

RESULTS

Basal salivary cortisol secretion was significantly higher in CHR patients who were medication-free compared to CHR patients taking medications and to healthy controls. In this small cohort, basal salivary cortisol secretion was associated at trend level with stress sensitivity, and was not significantly related to other symptoms.

CONCLUSIONS

Our finding of elevated basal cortisol secretion in CHR patients supports the premise that excess activation of the HPA axis and/or neuroendocrine abnormalities characterize the psychosis risk state for at least a subset of patients. Our findings further suggest that psychotropic medications may have a normalizing effect on HPA-axis dysfunction in CHR patients, which could potentially inform intervention strategies for the prodrome.

Neighbourhood deprivation and physical activity in UK older adults

The benefits of regular physical activity for older adults are now well-established but this group remain the least active sector of the population. In this paper, the association between levels of neighbourhood deprivation and physical activity was assessed. A sample of 125 males with a mean age of 77.5 (±5.6) years, and 115 females with a mean age of age 78.6 (±8.6) underwent 7-day accelerometry, a physical performance battery, and completed a daily journeys log. Univariate associations between physical activity parameters and level of deprivation of neighbourhood were extinguished in regression models controlling for age, gender, and level of educational attainment. Age, gender, educational attainment, body mass index, physical function, and frequency of journeys from the home explained between 50% and 54% of variance in activity parameters. These results suggest the importance of strategies to help older adults maintain physical function, healthy weight, and remain active in their communities.

Are American College of Rheumatology 50% response criteria superior to 20% criteria in distinguishing active aggressive treatment in rheumatoid arthritis clinical trials reported since 1997? A meta-analysis of discriminant capacities

OBJECTIVE

To carry out a meta-analysis designed to compare the discriminant capacities of American College of Rheumatology 50% (ACR50) with 20% (ACR20) responses in clinical trials on rheumatoid arthritis reported after 1997 and to analyse whether ACR50 can be as informative as ACR20 in distinguishing active from control treatments in more recent trials.

METHODS

Clinical trials on rheumatoid arthritis reported since 1997 were identified, which included aggressive combinations of disease-modifying antirheumatic drugs and glucocorticoids, as well as powerful new agents-leflunomide, etanercept, infliximab, anakinra, adalimumab, abatacept, tacrolimus and rituximab. A meta-analysis of ACR20 compared with ACR50 responses for 21 clinical trials was carried out on differences in proportions of responders for active and control treatments and corresponding odds ratios (ORs).

RESULTS

In all but one clinical trial on rheumatoid arthritis published since 1997 with data available on ACR20 and ACR50, more than 50% of patients who were ACR20 responders among those randomised to active treatment were also ACR50 responders. This phenomenon was seen for control groups in 38% of trials, many of which included treatment with methotrexate. A meta-analysis of the clinical trials indicated a slight advantage to ACR50 for quantifying treatment comparisons, not significant for differences in proportions but significant for ORs.

CONCLUSION

ACR20 and ACR50 seem to be similar in distinguishing active from control treatments in clinical trials on rheumatoid arthritis reported since 1997. As ACR50 represents a considerably stronger clinical response, ACR50 may be a preferred end point for contemporary clinical trials on rheumatoid arthritis.

Comparison of fibreoptic-guided orotracheal intubation through classic and single-use laryngeal mask airways

We compared times to intubate the trachea orally and success rates using two fibreoptically assisted techniques in 42 healthy patients with normal airways using (a) a 6.0-mm nasal RAE tracheal tube passed through a classic laryngeal mask airway (CLMA group) or (b) a 6.0-mm nasal RAE tracheal tube passed through a new disposable Portex Soft Seal laryngeal mask airway (PLMA group). The mean (SD) total intubation times were 82 (14) and 80 (17) s, respectively (p = 0.55). The success rates for intubation at the first attempt were similar (17/21 in the CLMA vs. 16/21 in the PLMA group; p = 0.50). We conclude that there is no clinically significant difference between the times to intubate the trachea or success rates using these two devices, but there may be other more subtle measures which might influence the choice of device in clinical practice. Finally, in the course of this study we developed a grading scale to describe the laryngeal views obtained when using a fibrescope passed through supraglottic airway devices.

Thrombin generation in non-cardioembolic stroke subtypes: The Hemostatic System Activation Study

BACKGROUND

The association between hemostatic activation, stroke mechanism, and outcome is poorly defined. The Hemostatic System Activation Study (HAS) investigators measured serial levels of prothrombin fragment F1.2, a marker of thrombin generation, in patients enrolled in the Warfarin Aspirin Recurrent Stroke Study (WARSS).

METHODS

HAS enrolled 631 of the 2,206 patients in WARSS. Strokes were subtyped according to inferred mechanism. Plasma was collected for F1.2 at randomization (within 30 days of stroke), 3 months, 12 months, and 18 months. The 3 to 6 month samples in aspirin-treated patients were used for the primary analysis.

RESULTS

The authors analyzed 3 to 6 month samples on 320 patients. Higher F1.2 levels were associated with older age, female sex, and hypertension. There was no difference between mean F1.2 levels in 56 cryptogenic (0.9 +/- 0.32 nmol/L) and 114 non-cryptogenic (1.13 +/- 0.74 nmol/L) patients or across specific stroke subtypes. There was an 8.8%/year (p = 0.006) increase in mean F1.2 levels. There was a trend toward higher risk of recurrent stroke or death as F1.2 levels increased in aspirin (RR: 1.30, 95% CI: 0.57 to 2.94, p = 0.53) and warfarin treated patients (RR: 1.68, 95% CI: 0.48 to 5.94, p = 0.42). F1.2 levels were reduced on average 70% in warfarin-treated patients in a dose-dependent fashion.

CONCLUSION

F1.2 levels did not appear to differ by stroke subtype, suggesting that factors other than underlying stroke pathophysiology influence thrombin generation in the post-acute stroke period. F1.2 levels were suppressed by warfarin in a dose-dependent fashion. Additional research is needed to determine the predictive value of F1.2 after stroke.

Control of calcium oscillations by membrane fluxes

It is known that Ca(2+) influx plays an important role in the modulation of inositol trisphosphate-generated Ca(2+) oscillations, but controversy over the mechanisms underlying these effects exists. In addition, the effects of blocking membrane transport or reducing Ca(2+) entry vary from one cell type to another; in some cell types oscillations persist in the absence of Ca(2+) entry (although their frequency is affected), whereas in other cell types oscillations depend on Ca(2+) entry. We present theoretical and experimental evidence that membrane transport can control oscillations by controlling the total amount of Ca(2+) in the cell (the Ca(2+) load). Our model predicts that the cell can be balanced at a point where small changes in the Ca(2+) load can move the cell into or out of oscillatory regions, resulting in the appearance or disappearance of oscillations. Our theoretical predictions are verified by experimental results from HEK293 cells. We predict that the role of Ca(2+) influx during an oscillation is to replenish the Ca(2+) load of the cell. Despite this prediction, even during the peak of an oscillation the cell or the endoplasmic reticulum may not be measurably depleted of Ca(2+).

Patterns of physical activity among American Indian children: an assessment of barriers and support

Estimates indicate that 10% to 50% of American Indian and non-Indian children in the U.S. are obese, defined as a body mass index > or = 95th percentile of the NHANES II reference data. Pathways is a two-phase, multi-site study to develop and test a school-based obesity prevention program in American Indian schoolchildren in grades three through five. During Phase I feasibility prior to initiation of the Pathways trial, data were collected related to physical activity patterns, and the supports of, and barriers to, physical activity. Nine schools from communities representing six different tribal groups participated in this study. Multiple measures were used for data collection including direct observation, paired child interviews, and in-depth interviews and focus groups with adults. Students completed the self-administered Knowledge, Attitudes, and Behaviors (KAB) survey, and a Physical Activity Questionnaire (PAQ). Barriers to physical activity at schools included a lack of facilities, equipment, and trained staff persons for PE. Adults were not consistently active with their children, but they were highly supportive of their children's activity level. Children reported a strong enjoyment of physical activity and strong peer support to be physically active. Weather conditions, safety concerns, and homework/chores were common barriers to physical activity reported by children and adult caregivers. The information was used to design culturally and age-appropriate, practical interventions including the five physical activity programs for schoolchildren in the Pathways study.

A comparison of warfarin and aspirin for the prevention of recurrent ischemic stroke

BACKGROUND

Despite the use of antiplatelet agents, usually aspirin, in patients who have had an ischemic stroke, there is still a substantial rate of recurrence. Therefore, we investigated whether warfarin, which is effective and superior to aspirin in the prevention of cardiogenic embolism, would also prove superior in the prevention of recurrent ischemic stroke in patients with a prior noncardioembolic ischemic stroke.

METHODS

In a multicenter, double-blind, randomized trial, we compared the effect of warfarin (at a dose adjusted to produce an international normalized ratio of 1.4 to 2.8) and that of aspirin (325 mg per day) on the combined primary end point of recurrent ischemic stroke or death from any cause within two years.

RESULTS

The two randomized study groups were similar with respect to base-line risk factors. In the intention-to-treat analysis, no significant differences were found between the treatment groups in any of the outcomes measured. The primary end point of death or recurrent ischemic stroke was reached by 196 of 1103 patients assigned to warfarin (17.8 percent) and 176 of 1103 assigned to aspirin (16.0 percent; P=0.25; hazard ratio comparing warfarin with aspirin, 1.13; 95 percent confidence interval, 0.92 to 1.38). The rates of major hemorrhage were low (2.22 per 100 patient-years in the warfarin group and 1.49 per 100 patient-years in the aspirin group). Also, there were no significant treatment-related differences in the frequency of or time to the primary end point or major hemorrhage according to the cause of the initial stroke (1237 patients had had previous small-vessel or lacunar infarcts, 576 had had cryptogenic infarcts, and 259 had had infarcts designated as due to severe stenosis or occlusion of a large artery).

CONCLUSIONS

Over two years, we found no difference between aspirin and warfarin in the prevention of recurrent ischemic stroke or death or in the rate of major hemorrhage. Consequently, we regard both warfarin and aspirin as reasonable therapeutic alternatives.

Functional MRI of language processing: dependence on input modality and temporal lobe epilepsy

PURPOSE

Functional magnetic resonance imaging (MRI) using two language-comprehension tasks was evaluated to determine its ability to lateralize language processing and identify regions that must be spared in surgery.

METHODS

Two parallel cognitive language tasks, one using auditory input and the other visual input, were tested in a group of control subjects and in temporal lobe epilepsy patients who were candidates for surgical intervention. The patient studies provide an opportunity to compare functional MRI language localization with that obtained using Wada testing and electrocorticography. All of the patients in this study underwent all three procedures and a battery of neuropsychological testing. Such studies provide an opportunity not only to validate the fMRI findings but also, by comparing the patient results with those obtained in control subjects, to provide insight into the impact of a pathology such as epilepsy on cortical organization or functional patterns of activation.

RESULTS

The results reveal both modality-dependent and modality-independent language-processing patterns for visual versus auditory task presentation. The visual language task activated distinct sites in Broca's area, BA (Brodmann area) 44 that were not activated in the auditory language task. The auditory language task strongly activated contralateral right BA22-21 area (homologous to Wernicke's area on the left). Language lateralization scores were significantly stronger for visual than for auditory task presentation. The conjunction of activation from the two different input modalities (modality-independent areas) likely highlights regions that perform more abstract computations (e.g., syntactic or pragmatic processing) in language processing. Modality-specific areas (e.g., right Wernicke, left fusiform gyrus, Broca BA44, supramarginal gyrus), appear to cope with the computations relevant to making contact with these more abstract dimensions. Patients showed recruitment of contralateral homologous language areas (p < 0.005) that was significantly above that found in a normal control group. Extra- and intraoperative cortical stimulations were concordant with the fMRI data in eight of 10 cases. The fMRI lateralization scores were also consistent with the Wada testing in 8/10 patients.

CONCLUSIONS

The fMRI results demonstrate that the epileptic brain may be a progressive model for cortical plasticity.

Reciprocal regulation of capacitative and arachidonate-regulated noncapacitative Ca2+ entry pathways

Receptor-activated Ca(2+) entry is usually thought to occur via capacitative or store-operated Ca(2+) channels. However, at physiological levels of stimulation, where Ca(2+) store depletion is only transient and/or partial, evidence has suggested that an arachidonic acid-dependent noncapacitative Ca(2+) entry is responsible. Recently, we have described a novel arachidonate-regulated Ca(2+)-selective (ARC) conductance that is entirely distinct from store-operated conductances in the same cell. We now show that these ARC channels are indeed specifically activated by low agonist concentrations and provide the predominant route of Ca(2+) entry under these conditions. We further demonstrate that sustained elevations in cytosolic Ca(2+), such as those resulting from activation of store-operated Ca(2+) entry by high agonist concentrations, inhibit the ARC channels. This explains earlier failures to detect the presence of this noncapacitative pathway in experiments where store-operated entry had already been fully activated. The result is that the respective activities of ARC and store-operated Ca(2+) channels display a unique reciprocal regulation that is related to the specific nature of the [Ca(2+)](i) signals generated at different agonist concentrations. Importantly, these data show that at physiologically relevant levels of stimulation, it is the noncapacitative ARC channels that provide the predominant route for the agonist-activated entry of Ca(2+).

Review of spaceflight and hindlimb suspension unloading induced sarcomere damage and repair

Hindlimb suspension unloading (HSU) and spaceflight microgravity induce atrophy of the slow adductor longus muscle fibers which, following reloading, exhibit eccentric contraction (EC)-like lesions (abnormal widening of sarcomeres with A band disruption and excessively wavy, extracted Z lines). These lesions are similar morphologically to those produced in normal muscles after strenuous eccentric exercise. It appears that atrophic muscles exhibit increased susceptibility to eccentric damage because lesions are produced during nonstressful voluntary movements upon return to weightbearing. The EC-like lesions are absent in the unweighted conditions, but appear in HSU rats 15-60 minutes after reloading and in space-flown rates about 4 hrs after landing. By 12 hours, many EC-like lesioned sarcomeres are fully covered by longitudinal patches of Z line-like material which increases in density by 48 hours, producing the so-called "Z line streaming" morphology. In this case, Z line streaming is indicative of rapid repair of damaged sarcomeres rather than the onset of sarcomere breakdown. Immunoelectron microscopy is necessary to determine the composition of this dense material. By 9 days of reloading at 1 gravity, sarcomeres have regained normal structure, except for very rare persistence of faint Z patches. The morphological data indicate that Z patches serve at least two functions: 1) to permit contractile force to be transmitted across the damaged sarcomeres and 2) to provide a scaffold upon which sarcomeres are reconstructed in an active functional muscle.

Glycine antagonist in neuroprotection for patients with acute stroke: GAIN Americas: a randomized controlled trial

CONTEXT

Elucidation of the ischemic cascade has helped stimulate development of neuroprotective drugs aimed at limiting brain injury in the hours following an ischemic stroke. To date, none of these drugs has shown clinical efficacy.

OBJECTIVE

To examine the efficacy of gavestinel (GV150526), an antagonist of the glycine site of the N-methyl-D-aspartate receptor, as a neuroprotective therapy for acute ischemic stroke when administered within 6 hours of symptom onset.

DESIGN

The Glycine Antagonist in Neuroprotection (GAIN) Americas trial, a randomized, double-blind placebo-controlled trial with enrollment from April 1998 to October 1999.

SETTING

One hundred thirty-two hospital centers across the United States and Canada.

PATIENTS

The primary efficacy population consisted of 1367 ischemic stroke patients with a predefined level of limb weakness and functional independence prior to stroke, stratified at randomization by age (</=75 vs >75 years) and initial stroke severity (National Institutes of Health [NIH] Stroke Scale scores of 2-5, 6-13, or >/=14).

INTERVENTION

Patients were randomly assigned to receive an intravenous loading dose (800 mg) plus 5 maintenance doses (200 mg every 12 hours) of gavestinel (n = 701) or placebo (n = 666) for 3 days.

MAIN OUTCOME MEASURE

Functional capability at 3 months, measured by the Barthel Index (BI), with scores trichotomized as dead/0-55, 60-90, and 95-100, compared between the gavestinel and placebo groups.

RESULTS

Treatment groups were well matched for baseline characteristics. For each group, median NIH Stroke Scale was 12, median age was 72 years, and median time to treatment was 5.2 hours. No statistically significant improvement on the 3-month BI trichotomy was demonstrated for gavestinel (P =.79). The proportion who were functionally independent (BI score = 95-100) was 39% in the gavestinel group and 37% in the placebo group. No statistically significant difference in 3-month survival was observed using Kaplan-Meier curves (P =.11). No other secondary end point suggested an advantage for gavestinel. Among the 333 patients (24%) who received recombinant tissue-type plasminogen activator, there was also no benefit for gavestinel (P =.53). There were no serious safety issues.

CONCLUSION

In this study, gavestinel administered up to 6 hours after an acute ischemic stroke did not improve functional outcome at 3 months.

Fiber-type susceptibility to eccentric contraction-induced damage of hindlimb-unloaded rat AL muscles

Slow oxidative (SO) fibers of the adductor longus (AL) were predominantly damaged during voluntary reloading of hindlimb unloaded (HU) rats and appeared explainable by preferential SO fiber recruitment. The present study assessed damage after eliminating the variable of voluntary recruitment by tetanically activating all fibers in situ through the motor nerve while applying eccentric (lengthening) or isometric contractions. Muscles were aldehyde fixed and resin embedded, and semithin sections were cut. Sarcomere lesions were quantified in toluidine blue-stained sections. Fibers were typed in serial sections immunostained with antifast myosin and antitotal myosin (which highlights slow fibers). Both isometric and eccentric paradigms caused fatigue. Lesions occurred only in eccentrically contracted control and HU muscles. Fatigue did not cause lesions. HU increased damage because lesioned- fiber percentages within fiber types and lesion sizes were greater than control. Fast oxidative glycolytic (FOG) fibers were predominantly damaged. In no case did damaged SO fibers predominate. Thus, when FOG, SO, and hybrid fibers are actively lengthened in chronically unloaded muscle, FOG fibers are intrinsically more susceptible to damage than SO fibers. Damaged hybrid-fiber proportions ranged between these extremes.

Recombinant human growth hormone, but not insulin-like growth factor-I, enhances central fat loss in postmenopausal women undergoing a diet and exercise program

We examined the effect of recombinant human growth hormone (rhGH) and/or recombinant human insulin-like growth factor-I (rhIGF-l) on regional fat loss in postmenopausal women undergoing a weight loss regimen of diet plus exercise. Twenty-seven women aged 59-79 years, 20-40% above ideal body weight, completed a 12-week program consisting of resistance training 2 days/week and walking 3 days/week, while consuming a diet that was 500 kcal/day less than that required for weight maintenance. Participants were randomly assigned in a double-blind fashion to receive rhGH (0.025 mg/kg BW/day; n = 7), rhIGF-I (0.015 mg/kg BW/day; n = 7), rhGH + rhIGF-I (n = 6), or placebo (PL; n = 7). Regional and whole body fat mass were determined by dual X-ray absorptiometry. Body fat distribution was assessed by the ratios of trunk fat-to-limb fat (TrF/LimbF) and trunk fat-to-total fat (TrF/TotF). Limb and trunk fat decreased in all groups (p < 0.01). For both ratios of fat distribution, the rhGH treated group experienced an enhanced loss of truncal compared to peripheral fat (p < 0.01), with no significant change for those administered rhIGF-I or PL. There was no association between change in fat distribution and indices of cardiovascular disease risk as determined by serum lipidilipoprotein levels and maximal aerobic capacity. These results suggest that administration of rhGH facilitates a decrease in central compared to peripheral fat in older women undertaking a weight loss program that combines exercise and moderate caloric restriction, although no beneficial effects are conferred to lipid/lipoprotein profiles. Further, the effect of rhGH is not enhanced by combining rhGH with rhIGF-I administration. In addition, rhIGF-I does not augment the loss of trunk fat when administered alone.

Immunohistochemical myofiber typing and high-resolution myofibrillar lesion detection in LR white embedded muscle

We have developed a method of fixing, embedding, sectioning, and staining that allows high-resolution detection of myofibrillar structure and myosin immunocytochemical muscle fiber typing in serial semithin sections of LR White plastic embedded muscle at the light microscopic level. Traditional approaches, such as cryostat sections, permit fiber typing, but small myofibrillar lesions (1-3 sarcomeres) are difficult to detect because of section thickness. Semithin sections of hydrophobic resins do not stain well either histochemically or immunocytochemically. Electron microscopy can resolve lesions and discriminate fiber types based on morphology, but the sampling area is small. Our goal was to develop a rapid method for defining both fiber type and high-resolution primary myofibrillar lesion damage. Mild fixation (1-4% paraformaldehyde, 0. 05-0.1% glutaraldehyde) and embedment in a hydrophilic resin (LR White) were used. Myofibrillar structure was extremely well preserved at the light microscopic (LM) level, and lesions could be readily resolved in Toluidine blue stained 500-nm sections. Fiber type was defined by LM immunomyosin staining of serial plastic semithin sections, which demonstrated reciprocal staining patterns for "fast (Sigma M4276) and "total" (skeletal muscle) myosins (Sigma M7523).

The place of Neandertals in the evolution of hominid patterns of growth and development

This study uses the two developmental fields of dental maturation and femoral growth to determine if the pattern of growth and development in Neandertals (archaic Homo sapiens) was intermediate between that of Homo erectus and recent modern humans. Specimens used in the analysis included Neandertals and Upper Palaeolithic early modern Homo sapiens from Europe and individuals from two recent modern human populations. Ontogenetic data for the H. erectus adolescent KNM-WT 15000 and for Gorilla gorilla were included for comparison. Previous reports have indicated that H. erectus demonstrates a pattern of ontogeny characterized by earlier and more rapid linear growth than in modern humans. Results reported here demonstrate that Upper Paleolithic early modern Homo sapiens display a growth trajectory indistinguishable from that of recent modern humans. The pattern of Neandertal ontogeny is not intermediate between the pattern displayed in H. erectus and the derived pattern seen in the modern reference samples and the early modern H. sapiens sample. The Neandertal growth trajectory is consistent with either slow linear growth or advanced dental development.

Improvement strategies in free-throw shooting and grip-strength tasks

Participants performed a free-throw shooting task and a grip-strength task before and after imagery, nonspecific arousal, or no instructions. Imagery improved performance in the free-throw shooting task, which is assumed to have more cognitive components than the grip-strength task. Imagery did not improve performance in the grip-strength task, which is assumed to have fewer cognitive components than the free-throw task. Nonspecific arousal, on the other hand, improved performance in the grip-strength task but not in the free-throw shooting task. Athletic experience, confidence levels, and gender were correlated with actual performance levels in both tasks, but not with improvement. Results are discussed within the transfer-appropriate processing framework.

Decreased thin filament density and length in human atrophic soleus muscle fibers after spaceflight

Soleus muscle fibers were examined electron microscopically from pre- and postflight biopsies of four astronauts orbited for 17 days during the Life and Microgravity Sciences Spacelab Mission (June 1996). Myofilament density and spacing were normalized to a 2. 4-microm sarcomere length. Thick filament density ( approximately 1, 062 filaments/microm(2)) and spacing ( approximately 32.5 nm) were unchanged by spaceflight. Preflight thin filament density (2, 976/microm(2)) decreased significantly (P < 0.01) to 2,215/microm(2) in the overlap A band region as a result of a 17% filament loss and a 9% increase in short filaments. Normal fibers had 13% short thin filaments. The 26% decrease in thin filaments is consistent with preliminary findings of a 14% increase in the myosin-to-actin ratio. Lower thin filament density was calculated to increase thick-to-thin filament spacing in vivo from 17 to 23 nm. Decreased density is postulated to promote earlier cross-bridge detachment and faster contraction velocity. Atrophic fibers may be more susceptible to sarcomere reloading damage, because force per thin filament is estimated to increase by 23%.

Stroke in patients with heart failure and reduced left ventricular ejection fraction

BACKGROUND

Cardiac failure is associated with both stroke of presumed cardioembolic origin and a high mortality rate. Warfarin is used frequently in patients with reduced cardiac left ventricular ejection fraction (EF), although no randomized trials have confirmed that anticoagulation benefits these patients.

METHODS

A literature review was performed pertaining to the frequency of stroke and mortality, and the effect of antithrombotic agents on stroke and mortality rates, in patients with cardiac failure or reduced cardiac EF. We also reviewed the main features of two new proposed studies (Warfarin and Antiplatelet Therapy in Chronic Heart Failure [WATCH] and Warfarin Versus Aspirin in Reduced Cardiac Ejection Fraction [WARCEF]) comparing warfarin and antiplatelet agents in patients with low EF.

RESULTS

The risk of stroke increases with decreasing EF and the risk of mortality increases with the clinical severity of cardiac failure (New York Heart Association class). Data from heart failure treatment studies suggest that warfarin may reduce stroke and mortality in patients with reduced EF, but definitive answers are lacking. The stroke rate alone is too low to be used as a primary endpoint, but an endpoint combining stroke and death (as WARCEF and WATCH propose) should allow an assessment of the effect of antithrombotics in cardiac failure. Amalgamating the data on stroke from these two trials should yield enough statistical power to compare the effects of warfarin and aspirin on stroke as an independent secondary endpoint.

CONCLUSION

Whether warfarin is superior to aspirin in reducing stroke and mortality in patients with low ejection fraction is an important clinical issue that warrants prospective evaluation.

Transcranial Doppler waveform blunting in severe extracranial carotid artery stenosis

OBJECTIVE

To investigate the frequency of transcranial Doppler (TCD) waveform blunting in patients with severe (80-99%) symptomatic or asymptomatic extracranial carotid artery stenosis.

BACKGROUND

Severe carotid artery stenosis has been identified as a risk factor for ischemic stroke. Blunted Doppler flow waveforms (reduced systolic flow velocity and pulsatility) of the middle cerebral artery (MCA) are inferred to reflect hemodynamic impairment, possibly indicating an increased risk of stroke.

METHODS

The 114 consecutive patients (mean age 72.4 years, SD 9.0 years; 37% women; 46 clinically symptomatic, 68 asymptomatic) with 80-99% stenosis of the extracranial internal carotid artery (ICA), as determined by duplex sonography, were examined with TCD. Flow velocities, pulsatility index, and spectral waveforms of the MCA distal to the ICA stenosis were assessed blinded to the clinical status of the ICA: Doppler waveform blunting was defined as loss of the characteristic systolic peak. Odds ratios with 95% confidence intervals and chi(2) statistics were used to describe the association between waveform blunting and the symptomatic status of the ICA stenosis.

RESULTS

Among symptomatic patients, 23 (50%) had completed strokes, and a further 23 (50%) had transient neurologic deficits in the territory of the stenotic ICA. Blunted spectral waveform was found in 37 (80%, 95% CI 68-92%) of the symptomatic and 25 (37%; 95% CI 25-49%) of the asymptomatic patients. Symptomatic patients had significantly increased odds of having blunted TCD waveforms (OR 7.5, 95% CI 3.1-18.1, p < 0.001).

CONCLUSIONS

Our findings suggest that TCD waveform blunting in the MCA as here described may be an additional risk factor in the setting of severe extracranial carotid artery stenosis. A prospectively designed study to confirm our results seems warranted.

Discriminating between capacitative and arachidonate-activated Ca(2+) entry pathways in HEK293 cells

We have recently questioned whether the capacitative or store-operated model for receptor-activated Ca(2+) entry can account for the influx of Ca(2+) seen at low agonist concentrations, such a those typically producing [Ca(2+)](i) oscillations. Instead, we have identified an arachidonic acid-regulated, noncapacitative Ca(2+) entry mechanism that appears to be specifically responsible for the receptor-activated entry of Ca(2+) under these conditions. However, it is unclear whether these two systems reflect the activity of distinct entry pathways or simply different mechanisms of regulating a common pathway. We therefore used the known selectivity of the Ca(2+)-stimulated type VIII adenylyl cyclase for Ca(2+) entry occurring via the capacitative pathway (Fagan, K. A., Mahey, R., and Cooper, D. M. F. (1996) J. Biol. Chem. 271, 12438-12444) to attempt to discriminate between these two entry mechanisms in HEK293 cells. Consistent with the earlier reports, we found that thapsigargin induced an approximate 3-fold increase in adenylyl cyclase activity that was unrelated to global changes in [Ca(2+)](i) or to the release of Ca(2+) from internal stores but was specifically dependent on the induced capacitative entry of Ca(2+). In marked contrast, the arachidonate-induced entry of Ca(2+) completely failed to affect adenylyl cyclase activity despite producing a substantially greater rate of entry than that induced by thapsigargin. These data demonstrate that the arachidonate-activated entry of Ca(2+) occurs via an entirely distinct influx pathway.

Prospective study on the complication rate of carotid surgery

BACKGROUND

Randomized trials of carotid endarterectomy for high-grade stenosis have shown a benefit for surgery under the condition of low perioperative complication rates. Concerns have been expressed that the complication rates of carotid surgery are higher in everyday practice and may vary considerably between centers. We prospectively established the complication rate for carotid surgery in a single institution.

DESIGN

Prospective 2-year study. All patients received pre- and postoperative neurological evaluation. Laboratory tests included pre- and postoperative brain imaging, intracranial and neck vessel sonography, conventional angiography, magnetic resonance angiography, and intraoperative monitoring.

PARTICIPANTS

108 consecutive patients: 54 symptomatic patients fulfilling the inclusion criteria of the European Carotid Surgery Trial (ECST) and 54 asymptomatic patients fulfilling the inclusion criteria of the North American Trial on Asymptomatic Stenoses (ACAS).

SETTING

Single academic center with a high volume of carotid endarterectomies (>50 per year). Participating center in ECST.

MAIN OUTCOME MEASURES

Stroke or death as defined in the randomized trials.

RESULTS

The overall complication rate was 8.3% (95% CI 4.1-15.6%). Complications were more frequent in patients with symptomatic stenosis (11.1%, CI 4.6-23.3%) than in asymptomatic cases (5.6%, CI 1.5-16.4%). Three patients died (2 strokes, 1 myocardial infarction). Disabling strokes were found in 2 patients (Rankin scale scores 3 and 4). Nondisabling strokes (Rankin scale score 1 and 2) occurred in 4 patients. The complication rates for symptomatic and asymptomatic patients were higher than the ones reported in the randomized trials, but 95% confidence intervals showed that the differences were not statistically significant. The point estimates of complication rates still supported a benefit of surgery for patients with symptomatic stenosis, but denied a positive effect of endarterectomy for patients with asymptomatic stenosis.

CONCLUSION

In this center, a beneficial effect of carotid surgery for asymptomatic stenoses cannot be safely assumed.

Long-term inpatient audiovisual scalp EEG monitoring

Long-term audiovisual scalp EEG monitoring is an essential diagnostic tool for the evaluation of paroxysmal disorders. The definitive classification of both nonepileptic and epileptic events is often possible only with the use of this technique. Assessment of response to treatment and the noninvasive presurgical localization of seizure foci are other important uses. The optimization of both clinical semiology and electrophysiologic data obtained from such studies is the subject of significant research efforts. Outcomes studies and advanced EEG analysis research should ultimately serve to minimize the cost of this valuable technique as well as maximizing its utility.

Interrater reliability of plaque morphology classification in patients with severe carotid artery stenosis

OBJECTIVE

Ultrasonographic assessment of carotid artery plaque morphology is widely used to identify patients at high risk for stroke. However, the reliability of plaque analysis in high-grade stenosis is uncertain. We determined the interrater reliability of sonographic plaque morphology analysis in patients with severe carotid artery stenosis.

MATERIALS AND METHODS

Duplex Doppler was performed on 114 patients with 80-99% stenosis of the internal carotid artery using a Siemens Quantum 2000 D with a handheld 7.5 MHz transducer. B-mode pictures with and without color coding were printed on a Sony color video printer UP-5000 W. Three raters independently evaluated plaque echolucency, heterogeneity, calcification, and surface structure. Interrater agreement was calculated by a jackknife procedure generating kappa values and two-sided 95% confidence intervals.

RESULTS

Kappa values and 95% confidence intervals were 0.05 (-0.07 to 0.16) for plaque surface structure, 0.15 (0.02 to 0.28) for plaque heterogeneity, 0.18 (0.09 to 0.29) for plaque echogenicity, and 0.29 (0.19 to 0.39) for plaque calcification. The upper bounds of all of the confidence intervals were below the 0.40 level suggested for minimal reliability.

CONCLUSION

The low interrater agreement indicated that unaided visual assessment of static B-mode pictures to assess plaque morphology in patients with severe carotid artery stenosis is not reliable. Other evaluation procedures and standardized criteria, as yet undeveloped, are needed to improve reliability.

Five myofibrillar lesion types in eccentrically challenged, unloaded rat adductor longus muscle--a test model

Sarcomere disruptions are observed in the adductor longus (AL) muscles following voluntary reloading of spaceflown and hindlimb suspension unloaded (HSU) rat, which resemble lesions in eccentrically challenged muscle. We devised and tested an eccentric contraction (ECCON) test system for the 14-day HSU rat AL. Six to 7 hours following ECCON, ALs were fixed to allow immunostaining and electron microscopy (EM). Toluidine blue-stained histology semithin sections were screened for lesion density (#/mm2). Serial semithin sections from the ECCON group were characterized for myosin immunointensity of lesions. Five myofibrillar lesion types were identified in histological semithin sections: focal contractions; wide A-bands; opaque areas; missing A-bands; and hyperstretched sarcomeres. Lesion density by type was greater for ECCON than NonECCON ALs (P< or =0.05; focal contractions and opaque regions). Lesion density (#-of-all-five-types/mm2) was significantly different (ECCON: 23.91+/-10.58 vs. NonECCON: 5.48+/-1.28, P< or =0.05; ECCON vs. SHAM: 0.00+/-0.00; P< or = 0.025). PostECCON optimal tension decreased (Poi-drop, 17.84+/-4.22%) and was correlated to lesion density (R2=0.596), but prestretch tension demonstrated the highest correlation with lesion density (R2=0.994). In lesions, the darkly staining A-band lost the normally organized thick filament alignment to differing degrees across the different lesion types. Ranking the five lesion types by a measure of lesion length deformation (hypercontracted to hyperstretched) at the light microscopy level, related to the severity of thick filament registry loss across the lesion types at the electron microscopic level. This ranking suggested that the five lesion types seen in semithin sections at the light level represented a lesion progression sequence and paralleled myosin immunostaining loss as the distorted A-band filaments spread across the hyperlengthening lesion types. Lesion ultrastructure indicated damage involved calcium homeostasis loss (focal contraction lesions) and "thick-filament-centering" failure of titin (wide A-band lesions) in the early stages of lesion development.

Muscarinic receptor activation of arachidonate-mediated Ca2+ entry in HEK293 cells is independent of phospholipase C

Receptor-enhanced entry of Ca2+ in non-excitable cells is generally ascribed to a capacitative mechanism in which the activation of the entry pathway is specifically dependent on the emptying of agonist-sensitive intracellular Ca2+ stores. Although such entry can be clearly demonstrated under conditions of maximal or near-maximal stimulation, it is uncertain whether such a mechanism can operate during the oscillatory [Ca2+]i signals that are frequently seen following stimulation with low concentrations of agonists. In this study, we report that the stimulation of human m3 muscarinic receptors stably transfected into HEK293 cells results in the appearance of a novel arachidonate-mediated Ca2+ entry pathway. We show that the generation of arachidonic acid and the activation of this pathway are specifically associated with stimulation at the low agonist concentrations that typically give rise to oscillatory [Ca2+]i signals. At such agonist concentrations, however, the generation of arachidonic acid is independent of the simultaneous activation of the phospholipase C-inositol 1,4,5-trisphosphate pathway. We further show that the arachidonate-mediated Ca2+ entry demonstrates characteristics that distinguish it from the corresponding capacitative pathway in the same cells and therefore is likely to represent an entirely distinct pathway that is specifically responsible for the receptor-enhanced entry of Ca2+ during [Ca2+]i oscillations.

A new reconstruction of the Le Moustier 1 skull and investigation of internal structures using 3-D-muCT data

Using the non-destructive technique of 3-D micro computed tomography (3-D-microCT), we present a new, virtual reconstruction of the Le Moustier 1 Neandertal skull. This new reconstruction corrects defects found in earlier reconstruction attempts by repositioning misaligned cranial fragments, addressing the problem of asymmetry caused by pressure during the fossilization process, and placing the basioccipital in its proper anatomical position. Metric comparisons between Le Moustier 1 and juvenile and adult Neandertals demonstrate that facial height proceeded at a faster rate of growth than facial prognathism at the beginning of the adolescent period. They also confirm the anterior placement of the basioccipital. A compound painted to match the colour of the fossilized bone was used in previous reconstruction attempts and the aim of this analysis was to remove the false material to reveal to what extent the fossilized bone was preserved. The areas with the most artificial material and glue include the palate, areas around the mandibular teeth, the left frontal, and parts of the right parietal and temporal bones. The microCT data were also used to examine internal structures of the skull including the frontal sinus and the labyrinth of the inner ear. An investigation of the frontal sinus reveals morphology similar to that found in adult Neandertals, although the structure does not extend to mid-orbit. The dimension of the radius of curvature of the lateral semicircular canal falls within one standard deviation, and the anterior and posterior canals within two standard deviations, of the published Neandertal mean. As in other Neandertals, the posterior semicircular canal is in an inferior position relative to the plane of the lateral canal.

Disproportionate loss of thin filaments in human soleus muscle after 17-day bed rest

Previously we reported that, after 17-day bed rest unloading of 8 humans, soleus slow fibers atrophied and exhibited increased velocity of shortening without fast myosin expression. The present ultrastructural study examined fibers from the same muscle biopsies to determine whether decreased myofilament packing density accounted for the observed speeding. Quantitation was by computer-assisted morphometry of electron micrographs. Filament densities were normalized for sarcomere length, because density depends directly on length. Thick filament density was unchanged by bed rest. Thin filaments/microm2 decreased 16-23%. Glycogen filled the I band sites vacated by filaments. The percentage decrease in thin filaments (Y) correlated significantly (P < 0.05) with the percentage increase in velocity (X), (Y = 0.1X + 20%, R2 = 0.62). An interpretation is that fewer filaments increases thick to thin filament spacing and causes earlier cross-bridge detachment and faster cycling. Increased velocity helps maintain power (force x velocity) as atrophy lowers force. Atrophic muscles may be prone to sarcomere reloading damage because force/microm2 was near normal, and force per thin filament increased an estimated 30%.

Sarcomere lesion damage occurs mainly in slow fibers of reloaded rat adductor longus muscles

Sarcomere lesions were previously observed with reloading of rat adductor longus muscles after spaceflight and hindlimb unloading (HU). Spaceflown rats displayed more lesioned fibers in the "slow-fiber" region, suggesting a damage-susceptible fiber type. Unloading induces fast myosin expression in some slow fibers, generating hybrid fibers. We examined whether lesion damage differed among slow-, hybrid-, and fast-fiber types in HU-reloaded adductor longus muscles. Temporal HU for 5, 8, 11, 14, and 17 days revealed that hybrid fiber percent, detected by antimyosin immunostaining, peaked at 29 +/- 12% by 14 days. A 14-day HU followed by 12-14 h of voluntary reloading was performed to induce lesions. chi2 analysis showed that slow fibers were preferentially damaged, accounting for 92 +/- 5% of lesioned fibers; hybrid and fast fibers accounted for 7 +/- 4 and <0.5%, respectively. Atrophy did not explain differential lesion damage across fiber types, as slow and hybrid fibers atrophied to a similar extent. Because active myofiber contractions are requisite for lesion formation, selective recruitment of slow fibers most likely explains their damage susceptibility.

Energy balance in young athletes

Very little is known about the energy needs of young athletes. Recent studies using the doubly labeled water method have shown that the recommended dietary allowances for energy may be too high for normally active children and adolescents living in affluent societies. No studies of energy balance in young athletes have been published. Self-report dietary records of young athletes indicate that energy, carbohydrate, and select micronutrient intakes of certain athletic groups and individual athletes may be marginal or inadequate. Potential consequences of inadequate energy and nutrient intakes in young athletes include poor bone health, fatigue, limited recovery from injuries, menstrual dysfunction in female athletes, and poor performance. Studies of energy balance and nutrient status in young athletes are needed to better understand the nutritional needs of this group.

Effects of human growth hormone, insulin-like growth factor I, and diet and exercise on body composition of obese postmenopausal women

To determine the effects of GH and insulin-like growth factor I (IGF-I) administration, diet, and exercise on weight loss, body composition, basal metabolic rate (BMR), muscle strength, and psychological status, 33 moderately obese postmenopausal women (67.1 +/- 5.2 yr) participated in a 12-week randomized, double blind study. Participants were placed on a diet that provided 500 Cal/day less than that needed for weight maintenance, and they walked 3 days and strength trained 2 days each week. Subjects also self-injected GH (0.025 mg/kg BW.day), IGF-I (0.015 mg/kg BW.day), a combination of these doses of GH and IGF-I, or placebo (P). Twenty-eight women completed the study, as five subjects dropped out due to intolerable side-effects (e.g. edema). Weight loss occurred in all groups, with the largest decrease occurring in the GH plus IGF-I group (5.6 +/- 1.4 kg). Fat mass significantly decreased in all groups, with the largest losses observed in GH and GH plus IGF-I groups (6.3 +/- 1.8 and 8.4 +/- 2.8 kg, respectively). Despite weight loss, BMR was maintained in all groups. Muscle strength increased with training for all groups, and depression and anxiety scores decreased in groups receiving IGF-I. These data show that obese postmenopausal women can lose weight and fat without compromising fat free mass, BMR, or gains in muscle strength, and that GH and IGF-I given together may enhance fat loss over either given alone.

Cigarette smoking as a determinant of high-grade carotid artery stenosis in Hispanic, black, and white patients with stroke or transient ischemic attack

BACKGROUND AND PURPOSE

We sought to investigate the association of cigarette smoking with high-grade carotid artery stenosis in Hispanic, black, and white patients with cerebral ischemia in two independent samples.

METHODS

Prospectively collected data from the Northern Manhattan Stroke Study (NOMASS) (n=431) and the Berlin Cerebral Ischemia Databank (BCID) (n=483) were used separately for a cross-sectional study estimating the association between cigarette smoking and high-grade carotid stenosis (defined as a luminal narrowing of > or =60%, diagnosed by duplex and/or Doppler ultrasound). In both studies, cerebral ischemia patients with normal sonographic findings or nonstenosing plaques of their carotid arteries served as a comparison group. Multivariate logistic regression models were used for statistical tests to determine the association between smoking and the dependent variable for high-grade carotid stenosis. Age, sex, hypertension, diabetes, hypercholesterolemia, and race/ethnicity were considered potential confounders. Further analyses of the NOMASS data estimated the effect of the amount of cigarette use and the impact of race/ethnicity.

RESULTS

High-grade carotid stenoses were found in 14% of the NOMASS and in 21% of the Berlin patients. In Berlin the entire sample was white, whereas in New York only 19% of the cohort were white. In both samples, smoking was independently associated with severe carotid stenosis (NOMASS: odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1 to 2.0; BCID: OR, 3.9; 95% CI, 2.4 to 6.4). Patients smoking 20 pack-years or more showed a significant association (OR, 2.0; 95% CI, 1.1 to 3.9), whereas no significant effect was found for lower amounts of cigarette use. In NOMASS, white smokers displayed a significant (OR, 3.2; 95% CI, 1.1 to 8.9) association with high-grade carotid stenosis, the association for black smokers was less strong, and no association was found among Hispanics.

CONCLUSIONS

Smoking is an independent determinant of severe carotid artery stenosis in patients with focal cerebral ischemia. The association differs by race/ethnicity, with the greatest effect observed among whites.

Frequency and determinants of microembolic signals on transcranial Doppler in unselected patients with acute carotid territory ischemia. A prospective study

BACKGROUND AND PURPOSE

Few data exist regarding to the occurrence of microembolic high-intensity transient signals (HITS) on transcranial Doppler ultrasound (TCD) in unselected acute stroke patients. The aim of this study was to investigate prospectively the frequency and determinants of HITS in acute carotid territory ischemia. We hypothesized that carotid artery disease, cardiac abnormalities, and nonlacunar infarcts were independent predictors of HITS in acute stroke.

METHODS

We investigated 145 consecutive patients with acute internal carotid artery territory ischemia. The median time interval between stroke and TCD examination was 2 days. TCD monitoring was performed for 30 min on each middle cerebral artery. The frequency of HITS was cross-classified with carotid artery status, potential cardiac sources of embolism, and nonlacunar infarct subtype. Multivariate logistic regression models determined the independent relationship of these variables to HITS.

RESULTS

Microembolic signals were detected in 35 patients (24.1%), Ipsilateral carotid artery disease was significantly and independently associated with HITS (odds ratio 3.3, 95% confidence interval 1.4-7.8, p = 0.007), whereas potential cardiac sources (OR 1.07, 95% CI 0.48-2.4, p = 0.84) and infarct subtype (OR 0.84, 95% CI 0.29-2.4, p = 0.75) were not.

CONCLUSIONS

High-intensity transient signals can be found in almost 25% of patients with acute anterior cerebral circulation ischemia and are significantly more prevalent among those with symptomatic carotid artery disease. Future clinical studies are required to determine whether HITS are a marker of increased stroke recurrence and can help to clarify stroke etiology in patients with competing stroke mechanisms.

[Effect of cardiac embolism sources on origin of territorial cerebral infarcts]

BACKGROUND AND PURPOSE

To test the association of cardiac sources of embolism with territorial type brain infarcts.

METHODS

From a prospective cerebral ischemia data base the 106 consecutive patients with territorial type cerebral infarcts on computerized tomography were analyzed. The 85 consecutive patients with lacunar lesions served as a comparison group. The association of cardiac sources of embolism with territorial types infarcts was assessed using univariate Chi Square tests and logistic regression models. Cardiac sources of embolism were defined as:atrial fibrillation, left cardiac thrombi, valvular vegetations, wall motion and valvular abnormalities, left atrial enlargement, open foramen ovale, septal aneurysm, mitral valve prolaps, and aortic arch atherothrombosis (all findings--except for atrial fibrillation--assessed by echocardiography).

RESULTS

Atrial fibrillation was significantly associated with territorial type infarcts (odds ratio 2.2, 95% confidence interval 1.01-4.8). This effect was independent of additional cardiac diseases, other cardiac abnormalities, carotid artery stenosis, and patient age. Most likely due to the small sample size, left cardiac thrombi only showed a non-significant trend towards an association with territorial infarcts (odds ratio 3.0, 95% confidence interval 0.7-12.3). The rate of all other cardiac findings did not differ significantly between the comparison groups.

CONCLUSION

Atrial fibrillation and cardiac thrombi showed an association with territorial type infarcts. Other so-called cardiac sources of embolism--except for mechanical valves and bacterial endocarditis which were not represented in our sample--revealed no clinically relevant association with embolic brain infarct pattern.