The effect of anaesthetic use on healing in sub cutaneous abscess management: a retrospective before and after cohort study

INTRODUCTION

There is wide variation in the management of simple subcutaneous abscesses in the UK and no national guidelines describing best practice. During the SARS-CoV-2 pandemic, regional or local anaesthesia (LA) use was recommended instead of general anaesthesia. This study aimed to assess the effect of anaesthetic use on outcomes following incision and drainage (I&D) of simple subcutaneous abscesses.

METHODS

Two cohorts of patients undergoing abscess incision and drainage at St. James' University Hospital in Leeds were identified retrospectively over a 14-week period before (P1) and after (P2) the introduction of the COVID-19 anaesthetic guidelines. The number of follow-up appointments for repacking and representation to healthcare services 30 days after I&D were used as surrogate endpoints for wound healing.

RESULTS

A total of 133 patients were included (n=70, P1 and n=63, P2). Significantly more procedures were performed under LA after the intervention (84.1% vs 5.7%; p<0.0001) with a significant reduction in wound packing (68.3% vs 87.1%; p=0.00473). Follow-up analysis found no significant difference in the median number of follow-up appointments (7.46 vs 5.11; p=0.0731) and the number of patients who required ongoing treatment after 30 days (n=14, P1 vs n=14, P2; p=0.921).

CONCLUSIONS

Drainage of simple subcutaneous abscess under 5cm in diameter is safe under LA, with no significant difference in surrogate endpoints of wound healing observed in this patient cohort. Recurrent packing may not be required. Future work should explore patient-reported outcomes, including pain management, cosmesis and the cost and sustainability implications of a change in this common procedure.

O45 Gender representation in the authorship of surgical journals

Introduction

Despite the increase in female doctors graduating from medical schools internationally, gender disparity in surgery remains. This disparity is also evident in academic surgery. This study aims to quantify the extent of gender disparity in the authorship of articles in major surgical journals.

Method

The Top 10 Surgical Journals were identified using SCImago Journal Rank indicator. Authorship details for papers published in 2019 were collected. Authors were assigned as female, male or unknown using Gender API software (Gender API, Germany). For each journal, the percentage of first author, last author, corresponding author and all authors split by gender was interrogated. Gender differences by publication type were also identified.

Result

9 of the 10 journals had full names publicly available. Overall, 2414 manuscripts were interrogated which included 16,277 number of authors. Respectively, females and males accounted for 29.8% [22.9–34.9%] (N = 655) and 62.4% [56.3–70.2%] (N = 1419) of first authors, 20.6% [11.8–27.1%] (N = 453) and 74.2% [65.6–84.1%] (N = 1706) of last authors, 23.9% [14.9–29.6%] (N = 510) and 69.9% [60.5–79.3%] (N = 2341) of corresponding authors and in total 27% [19.4–31.6%] (N = 4298) and 65.5% [58.6–73.4%] (N = 9982) of all authors. The wide range in these results could be a result of various factors.

Conclusion

This study has identified a gender imbalance in authorship positions, with the greatest difference observed in the most senior author position. Whether this is reflective of the current disparity observed in senior academic surgery positions or due to gender discrimination is unclear.

Take-home Message

This study identified a gender imbalance in authorship positions of major surgical journals, which has implications for women who choose to pursue a career in academic surgery.

The quantitative impact of COVID-19 on surgical training in the United Kingdom

Background

COVID-19 has had a global impact on all aspects of healthcare including surgical training. This study aimed to quantify the impact of COVID-19 on operative case numbers recorded by surgeons in training, and annual review of competency progression (ARCP) outcomes in the UK.

Methods

Anonymized operative logbook numbers were collated from electronic logbook and ARCP outcome data from the Intercollegiate Surgical Curriculum Programme database for trainees in the 10 surgical specialty training specialties.

Operative logbook numbers and awarded ARCP outcomes were compared between predefined dates. Effect sizes are reported as incident rate ratios (IRR) with 95 per cent confidence intervals.

Results

Some 5599 surgical trainees in 2019, and 5310 in surgical specialty training in 2020 were included. The IRR was reduced across all specialties as a result of the COVID-19 pandemic (0.62; 95 per cent c.i. 0.60 to 0.64). Elective surgery (0.53; 95 per cent c.i. 0.50 to 0.56) was affected more than emergency surgery (0.85; 95 per cent c.i. 0.84 to 0.87). Regional variation indicating reduced operative activity was demonstrated across all specialties. More than 1 in 8 trainees in the final year of training have had their training extended and more than a quarter of trainees entering their final year of training are behind their expected training trajectory.

Conclusion

The COVID-19 pandemic has had a major effect on surgical training in the UK. Urgent, coordinated action is required to minimize the impacts from the reduction in training in 2020.

Delay to surgery in acute perforated and ischaemic gastrointestinal pathology: a systematic review

BACKGROUND

Patients with acute abdominal pathology requiring emergency laparotomy who experience a delay to theatre have an increased risk of morbidity, mortality and complications. The timeline between symptom onset and operation is ill defined with international variance in assessment and management. This systematic review aims to define where delays to surgery occur and assess the evidence for interventions trialled across Europe.

METHODS

A systematic review was performed searching MEDLINE and EMBASE databases (1 January 2005 to 6 May 2020). All studies assessing the impact of time to theatre in patients with acute abdominal pathology requiring emergency laparotomy were considered.

RESULTS

Sixteen papers, involving 50 653 patients, were included in the analysis. Fifteen unique timepoints were identified in the patient pathway between symptom onset and operation which are classified into four distinct phases. Time from admission to theatre (1-72 hours) and mortality rate (10.6-74.5 per cent) varied greatly between studies. Mean time to surgery was significantly higher in deceased patients compared with that in survivors. Delays were related to imaging, diagnosis, decision making, theatre availability and staffing. Four of five interventional studies showed a reduced mortality rate following introduction of an acute laparotomy pathway.

CONCLUSION

Given the heterogeneous nature of the patient population and pathologies, an assessment and management framework from onset of symptoms to operation is proposed. This could be incorporated into mortality prediction and audit tools and assist in the assessment of interventions.

Characterization of stimulus response curves obtained with transcranial magnetic stimulation from bilateral anterior digastric muscles in healthy subjects

PURPOSE

The purpose of the study was to describe measurements of stimulus-response curves in the anterior digastric muscle (ADM) bilaterally following transcranial magnetic stimulation (TMS) to the right and left hemispheres. The first dorsal interosseous muscle (FDI) was the control muscle.

MATERIALS AND METHODS

The subjects were 20 healthy young adults. Test sessions determined motor thresholds (MT) and stimulus-response curves (1.0, 1.2, 1.4, 1.6 × MT) from either the FDI or ADM following TMS to left and right hemispheres using the double cone coil. Bilateral recordings of MEPs in the left and right ADM allowed us to generate stimulus response curves following ipsilateral and contralateral TMS.

RESULTS

Intraclass correlation coefficients (ICC) for MEP amplitudes from ipsilateral and contralateral ADMs were >0.60 at motor threshold (MT) and >0.90 at stimulus intensities above MT. There was a linear increase in MEP amplitudes across stimulus intensities for the FDI following contralateral TMS, while MEP amplitudes from the ADM following contralateral and ipsilateral TMS increased linearly across stimulus intensities [F_{(3, 57) [Muscle × Recording Site × Stim Intensity]} = 33.57; p < 0.05]; (ηp2 = 0.64). The slopes of the stimulus-response curve of the contralateral FDI was greater than the slopes of the stimulus response curves of the ipsilateral and contralateral ADM (p < 0.05).

CONCLUSIONS

The current study provided insights on the methodology for recording stimulus response curves in the ADM with TMS. These findings may translate into a valid, reliable, and relevant clinical outcome to study the pathophysiology of the corticobulbar motor system.

O54: GENDER REPRESENTATION IN EDITORIAL BOARDS OF INTERNATIONAL GENERAL SURGERY JOURNALS

Introduction

Despite women constituting over half of new UK doctors, and a similar proportion worldwide, gender disparity remains an issue throughout academic medicine. Surgery has shown particularly slow progress towards gender parity. This study aims to quantify gender representation within editorial boards of the top 25 general surgical journals.

Method

All surgical journals were collated using the SCImago Journal Rank (SJR) and Journal Impact Factor (JIF). Non general surgery journals were excluded. Journals were contacted requesting gender editorial team demographics. Editorial board data was collected via journal websites on 20th November 2019.

Result

The top 25 surgical journals were determined through SJR and JIF ranking methods. Editorial board data was publicly available for 31 of these 32 different surgical journals. This data was then examined. Women accounted for 18.4% (576/3135) of total editorial board positions. Women constituted 12.5% (5/40) of Editors-in-Chief positions, 31.6% (31/98) of Deputy Editors and 17.2% (416/2415) of general editorial board positions.

Conclusion

For the first time, gender disparity has been demonstrated within editorial boards of the most prominent general surgery journals. The implications of such significant gender disparity are wide reaching. Action should be taken to champion fair female representation, eliminate risk of bias and provide more visible female role models in academic surgery.

Take-home message

For the first time, this study demonstrates gender disparity in Editorial boards of major general surgery journals. Action should be taken to champion fair female representation, eliminate risk of bias and provide more visible female role models in academic surgery.

Changes in Opioid Therapy Use by an Interprofessional Primary Care Team: A Descriptive Study of Opioid Prescription Data

OBJECTIVE

The purpose of this study was to describe changes in opioid-therapy prescription rates after a family medicine practice included on-site chiropractic services.

METHODS

The study design was a retrospective analysis of opioid prescription data. The database included opioid prescriptions written for patients seeking care at the family medicine practice from April 2015 to September 2018. In June 2016, the practice reviewed and changed its opioid medication practices. In April 2017, the practice included on-site chiropractic services. Opiod-therapy use was defined as the average rate of opioid prescriptions over all medical providers at the practice.

RESULTS

There was a significant decrease of 22% in the average monthly rate of opioid prescriptions after the inclusion of chiropractic services (F_1,40 = 10.69; P < .05). There was a significant decrease of 32% in the prescribing rate of schedule II opioids after the inclusion of chiropractic services (F_2,80 = 6.07 for the Group × Schedule interaction; P < .05). The likelihood of writing schedule II opioid prescriptions decreased by 27% after the inclusion of chiropractic services (odds ratio, 0.73; 95% confidence interval, 0.59-0.90). Changes in opioid medication practices by the medical providers included prescribing a schedule III or IV opioid rather than a schedule II opioid (F_6,76 = 29.81; P < .05) and a 30% decrease in the daily doses of opioid prescriptions (odds ratio, 0.70; 95% confidence interval, 0.50-0.98).

CONCLUSION

This study demonstrates that there were decreases in opioid-therapy prescribing rates after a family medicine practice included on-site chiropractic services. This suggests that inclusion of chiropractic services may have had a positive effect on prescribing behaviors of medical physicians, as they may have been able to offer their patients additional nonpharmaceutical options for pain management.

Gender representation in editorial boards of international general surgery journals

Background

Despite women constituting over half of new doctors, gender disparity remains an issue. Surgery has shown particularly slow progress towards gender parity. This study aimed to quantify gender representation within editorial boards of the highest ranking international general surgery journals.

Methods

Surgical journals were collated using two indices: SCImago Journal Rank (SJR) and Journal Impact Factor (JIF). Non-general surgery journals were excluded. Journals were contacted, requesting gender editorial team demographics. Editorial board data were collected via journal websites on 28 November 2019.

Results

The top 25 general surgery journals according to SJR and JIF ranking methods were determined, identifying 28 unique journals. Editorial board data were publicly available for 27 of these 28 surgical journals, and were examined. Women accounted for 20.2 per cent (568 of 2816) of total editorial board positions. Women constituted 11 per cent (4 of 36) of editor-in-chief positions, 32 per cent (29 of 92) of deputy editors, and 19.1 per cent (369 of 1935) of general editorial board positions.

Conclusion

The findings demonstrate gender disparity within editorial boards of the most prominent general surgery journals.

A High-Throughput BRET Cellular Target Engagement Assay Links Biochemical to Cellular Activity for Bruton's Tyrosine Kinase

Protein kinases are intensely studied mediators of cellular signaling. While traditional biochemical screens are capable of identifying compounds that modulate kinase activity, these assays are limited in their capability of predicting compound behavior in a cellular environment. Here, we aim to bridge target engagement and compound-cellular phenotypic behavior by utilizing a bioluminescence resonance energy transfer (BRET) assay to characterize target occupancy within living cells for Bruton's tyrosine kinase (BTK). Using a diverse chemical set of BTK inhibitors, we determine intracellular engagement affinity profiles and successfully correlate these measurements with BTK cellular functional readouts. In addition, we leveraged the kinetic capability of this technology to gain insight into in-cell target residence time and the duration of target engagement, and to explore a structural hypothesis.

A comparison of student performance and satisfaction between a traditional and integrative approach to teaching an introductory radiology course on the extremities

OBJECTIVE:

The purpose of the study was to compare student performance and student satisfaction ratings for an introductory extremities radiology course taught using 2 different educational methods.

METHODS:

One group of students was taught using a traditional face-to-face instruction method, and the other group received an integrative blended-learning approach. A multivariate analysis of scores on lecture and laboratory examinations was performed to detect differences in student performance between the 2 methods. An independent t test was performed to compare the final course averages between the 2 methods. χ² Analysis was used to compare the distribution of letter grades and levels of satisfaction between the 2 groups.

RESULTS:

Test scores were higher for the integrative approach than for the traditional face-to-face method ( p < .05). However, the differences were not meaningful, as the greatest improvement in correct responses was only for 2 questions. Students appeared to be more satisfied with the integrative approach when compared to the traditional method ( p < .05).

CONCLUSION:

Student satisfaction with the educational delivery methods in an introductory extremities radiology course using an integrative approach was greater than for the traditional face-to-face instruction method. Student performance was similar between the 2 cohorts.

Motor Neuron Excitability Attenuation as a Sequel to Lumbosacral Manipulation in Subacute Low Back Pain Patients and Asymptomatic Adults: A Cross-Sectional H-Reflex Study

OBJECTIVE

The purpose of the study was to compare a time series of tibial nerve H-reflex trials between patients with subacute low back pain (LBP) and asymptomatic adults using pre and post high-velocity, low-amplitude (HVLA) spinal manipulation (SM) and control procedures.

METHODS

Asymptomatic adults (n = 66) and patients with subacute LBP (n = 45) were randomized into 3 lumbosacral procedures: side-posture positioning, joint preloading with no thrust, and HVLA SM. A time series of 40 H_max/M_max ratios at a rate of 0.1 Hz were recorded in blocks of 10 trials at baseline and after the lumbosacral procedures at time points corresponding to immediately after, 5 minutes after, and 10 minutes after the procedure. Descriptive time series analysis techniques included time plots, outlier detection, and autocorrelation functions. A mixed analysis of variance model (group × procedure × time) was used to compare the effects of lumbosacral procedures on H_max/M_max ratios between the patients with subacute LBP and asymptomatic participants.

RESULTS

The time series analysis and the significant lumbosacral × time interaction term (P < .05) indicated that inhibition of the H_max/M_max ratios at the 10-second postlumbosacral procedure time point was greatest after the HVLA SM procedure. The effects of lumbosacral procedures on H_max/M_max ratios were similar between patients with subacute LBP and asymptomatic participants.

CONCLUSIONS

Although nonspecific effects of movement or position artifacts on the H_max/M_max ratio were present, a reliable and valid attenuation of the H_max/M_max ratio occurred as a specific aspect of HVLA SM in both asymptomatic adults and patients with subacute LBP.

Identification of imidazo[1,2-b]pyridazine TYK2 pseudokinase ligands as potent and selective allosteric inhibitors of TYK2 signalling

As a member of the Janus (JAK) family of non-receptor tyrosine kinases, TYK2 mediates the signaling of pro-inflammatory cytokines including IL-12, IL-23 and type 1 interferon (IFN), and therefore represents an attractive potential target for treating the various immuno-inflammatory diseases in which these cytokines have been shown to play a role. Following up on our previous report that ligands to the pseudokinase domain (JH2) of TYK2 suppress cytokine-mediated receptor activation of the catalytic (JH1) domain, the imidazo[1,2-b]pyridazine (IZP) 7 was identified as a promising hit compound. Through iterative modification of each of the substituents of the IZP scaffold, the cellular potency was improved while maintaining selectivity over the JH1 domain. These studies led to the discovery of the JH2-selective TYK2 inhibitor 29, which provided encouraging systemic exposures after oral dosing in mice. Phosphodiesterase 4 (PDE4) was identified as an off-target and potential liability of the IZP ligands, and selectivity for TYK2 JH2 over this enzyme was obtained by elaborating along selectivity vectors determined from analyses of X-ray co-crystal structures of representative ligands of the IZP class bound to both proteins.

Feasibility of using the patient-reported outcomes measurement information system in academic health centers: case series design on pain reduction after chiropractic care

OBJECTIVE

The purpose of this study was to test the utility of Patient-Reported Outcomes Measurement Information System (PROMIS) as a resource for collecting data on patient-reported outcomes (PRO) within academic health centers at a chiropractic college; and, to describe changes in PRO following pragmatic chiropractic care incorporating instrument-assisted soft tissue mobilization (IASTM) on pain symptoms.

METHODS

This was a pre-post intervention design without a control group (case series) involving 25 patients (14 females and 11 males; 40.5 ± 16.39 years, range 20-70 years) who completed their chiropractic care and their baseline and post-treatment pain assessments. The pragmatic chiropractic care intervention included both spinal manipulation and IASTM to treat pain symptoms. PRO's were collected using PROMIS to measure pain behavior, pain interference and pain intensity.

RESULTS

The average pre-post assessment interval was 33 ± 22.5 days (95% CI, 23-42 days). The durations of treatments ranged from one week to 10 weeks. The median number of IASTM treatments was six. Pre-post decreases in T-scores for pain behavior and pain interference were 55.5 to 48.4 and 57.7 to 48.4, respectively (P < .05). Only 12 patients had a baseline T-score for pain intensity greater than 50. The pre-post decrease in pain intensity T-scores for these 12 patients was from 53.4 to 40.9.

CONCLUSION

Within the limitations of a case series design, these data provide initial evidence on the utility of PROMIS instruments for clinical and research outcomes in chiropractic patients.

Changes in anthropometric measurements, body composition, blood pressure, lipid profile, and testosterone in patients participating in a low-energy dietary intervention

OBJECTIVE

The purpose of this study was to describe changes in anthropometric measurements, body composition, blood pressure, lipid profile, and testosterone following a low-energy-density dietary intervention plus regimented supplementation program.

METHODS

The study design was a pre-post intervention design without a control group. Normal participants were recruited from the faculty, staff, students, and community members from a chiropractic college to participate in a 21-day weight loss program. All participants (n = 49; 36 women, 13 men; 31 ± 10.3 years of age) received freshly prepared mostly vegan meals (breakfast, lunch, and dinner) that included 1200 to 1400 daily calories (5020.8 to 5857.6 J) for the women and 1600 to 1800 (6694.4 to 7531.2 J) daily calories for the men. Nutritional supplements containing enzymes that were intended to facilitate digestion, reduce cholesterol levels, increase metabolic rate, and mediate inflammatory processes were consumed 30 minutes before each meal. The regimented supplementation program included once-daily supplementation with a green drink that contained alfalfa, wheatgrass, apple cider vinegar, and fulvic acid throughout the study period. A cleanse supplementation containing magnesium, chia, flaxseed, lemon, camu camu, cat's claw, bentonite clay, tumeric, pau d'arco, chanca piedra, stevia, zeolite clay, slippery elm, garlic, ginger, peppermint, aloe, citrus bioflavonoids, and fulvic acid was added before each meal during week 2. During week 3, the cleanse supplementation was replaced with probiotic and prebiotic supplementation.

RESULTS

Multiple paired t tests detected clinically meaningful reductions in weight (- 8.7 ± 5.54 lb) (- 3.9 ± 2.5 kg), total cholesterol (- 30.0 ± 29.77 mg/dL), and low-density lipoprotein cholesterol (- 21.0 ± 25.20 mg/dL) (P < .05). There was a pre-post intervention increase in testosterone for men (111.0 ± 121.13 ng/dL, P < .05).

CONCLUSIONS

Weight loss and improvements in total cholesterol and low-density lipoprotein cholesterol levels occurred after a low-energy-density dietary intervention plus regimented supplementation program.

Progressive multifocal leukoencephalopathy with gastrointestinal disease in a pediatric kidney transplant recipient

PML is a demyelinating disease of the central nervous system caused by infection with JCV. Several cases of PML in bone marrow and solid organ transplant recipients have been reported in recent years. JCV has been isolated from the gastrointestinal mucosa of immunocompromised patients, but there are no published reports of PML associated with symptomatic gastrointestinal involvement in kidney transplant recipients. We report a case of a nine-yr-old girl with a kidney transplant who developed a severe gastrointestinal illness causing pseudo-obstruction in association with PML. JCV was suspected as the causative agent in this patient by the detection of high JCV titer through PCR analysis of the cerebrospinal fluid and blood and positive staining for simian virus 40 in the colon. JCV intestinal infection should be considered in kidney transplant recipients presenting with intestinal pseudo-obstruction.

Using genetics to enable studies on the prevention of Alzheimer's disease

Curing Alzheimer's disease (AD) remains an elusive goal; indeed, it may even prove to be impossible, given the nature of the disease. Although modulating disease progression is an attractive target and will alleviate the burden of the most severe stages, this strategy will not reduce the prevalence of the disease itself. Preventing or (as described in this article) delaying the onset of cognitive impairment and AD will provide the greatest benefit to individuals and society by pushing the onset of disease into the later years of life. Because of the high variability in the age of onset of the disease, AD prevention studies that do not stratify participants by age-dependent disease risk will be operationally challenging, being large in size and of long duration. We present a composite genetic biomarker to stratify disease risk so as to facilitate clinical studies in high-risk populations. In addition, we discuss the rationale for the use of pioglitazone to delay the onset of AD in individuals at high risk.

Using confidence-based marking in a laboratory setting: A tool for student self-assessment and learning

OBJECTIVE

Confidence-based marking (CBM), developed by A. R. Gardner-Medwin et al., has been used for many years in the medical school setting as an assessment tool. Our study evaluates the use of CBM in the neuroanatomy laboratory setting, and its effectiveness as a tool for student self-assessment and learning.

METHODS

The subjects were 224 students enrolled in Neuroscience I over a period of four trimesters. Regional neuroanatomy multiple choice question (MCQ) quizzes were administered the week following topic presentation in the laboratory. A total of six quizzes was administered during the trimester and the MCQ was paired with a confidence question, and the paired questions were scored using a three-level CBM scoring scheme.

RESULTS

Spearman's rho correlation coefficients indicated that the number of correct answers was correlated highly with the CBM score (high, medium, low) for each topic. The χ2 analysis within each neuroscience topic detected that the distribution of students into low, medium, and high confidence levels was a function of number of correct answers on the quiz (p < .05). Pairwise comparisons of quiz performance with CBM score as the covariate detected that the student's level of understanding of course content was greatest for information related to spinal cord and medulla, and least for information related to midbrain and cerebrum.

CONCLUSION

CBM is a reliable strategy for challenging students to think discriminately-based on their knowledge of material. The three-level CBM scoring scheme was a valid tool to assess student learning of core neuroanatomic topics regarding structure and function.

Effects of foot orthotics on running economy: methodological considerations

OBJECTIVE

The purpose of the study was to collect preliminary data to address methodological considerations that may impact subject-specific reactions to foot orthotics during running.

METHODS

Six endurance-trained recreational runners recruited from a chiropractic college campus wore their preferred running shoes and then inserted either their custom-made orthotics during 1 testing session or their shoe-fitted insoles during the other testing session. Comfort perception was measured for each footwear condition. Measurements of oxygen consumption (VO2) at several moderate exercise intensities, to mimic recreational running, generated an individual's economy-of-running line. Predicted running velocity at VO(2max) (vVO2max) was calculated as an index of endurance performance. Lower extremity muscle activity was recorded. Descriptive statistics, a repeated-measures analysis of variance model, and a paired t test were used to document any systematic changes in running economy, lower extremity muscle activities, and vVO2max within and across subjects as a function of footwear conditions.

RESULTS

Decreases in VO2 at several moderate exercise intensities (F((1,5)footwear) = 10.37, P = .023) and increases in vVO2max (t(5) = 4.20, P = .008) occurred in all 6 subjects while wearing their orthotic intervention vs their shoe-fitted insoles. There were no consistent changes in lower extremity muscle activity.

CONCLUSIONS

Methodological decisions to use a sustained incremental exercise protocol at several moderate exercise intensities and to measure comfort perception of a custom-molded foot orthosis were effective at documenting systematic improvements in running economy among the 6 recreational runners tested. The development of a less physically demanding sustained exercise protocol is necessary to determine underlying neuromuscular mechanisms and/or clinical effectiveness of orthotic interventions.

Effects of tea combined with high-protein meal replacement shakes on anthropometric measurements, lipid profiles, cellular biochemistry, neurochemistry, and microbial metabolism: a prospective observational study

OBJECTIVE

The purpose of this study was to report preliminary data on the effects of tea and high-protein meal replacement shakes on weight loss, waist-to-hip ratios, and lipid profiles in healthy subjects. Secondary analyses of urine samples assessed pre-post changes in cellular biochemistry, neurochemistry, and microbial metabolism.

METHODS

This study used a pre-post intervention design without a control group. Thirty healthy subjects (20-60 years of age; 23 women and 7 men) participated in a 28-day diet intervention program consisting of a cleansing day and 6 restricted diet days per week. On cleansing days, the subjects drank 4 oz of tea 4 times per day with a recommendation to drink at least 64 oz of filtered water. On the restricted diet days, the subjects drank 2 high-protein meal replacement shakes, consumed one 400- to 600-cal (1674.3-2511.5 joules) meal consisting of low-glycemic index foods, and drank at least 64 oz of filtered water.

RESULTS

Multiple paired t tests detected reductions in weight (6.4 lb), waist (1.9 in), and hip (1.1 in) measurements and in total cholesterol (13.3 mg/dL) and low-density lipoprotein cholesterol (11.4 mg/dL) (P < .05). Multiple paired t tests detected significant increases in energy metabolism from carbohydrates and amino acids and concomitant increases in oxidative stress (P < .05).

CONCLUSION

The data support the concept that a low-glycemic load diet intervention incorporating tea and high-protein meal replacement shakes may cause weight loss and improve lipid profiles. The significant physiologic changes from the urine samples did not reflect meaningful metabolic effects.

The reliability of the Associate Platinum digital foot scanner in measuring previously developed footprint characteristics: a technical note

OBJECTIVE

An ink pad and paper, pressure-sensitive platforms, and photography have previously been used to collect footprint data used in clinical assessment. Digital scanners have been widely used more recently to collect such data. The purpose of this study was to evaluate the intra- and interrater reliability of a flatbed digital image scanning technology to capture footprint data.

METHODS

This study used a repeated-measures design on 32 (16 male 16 female) healthy subjects. The following measured indices of footprint were recorded from 2-dimensional images of the plantar surface of the foot recorded with an Associate Platinum (Foot Levelers Inc, Roanoke, VA) digital foot scanner: Staheli index, Chippaux-Smirak index, arch angle, and arch index. Intraclass correlation coefficient (ICC) values were calculated to evaluate intrarater, interday, and interclinician reliability.

RESULTS

The ICC values for intrarater reliability were greater than or equal to .817, indicating an excellent level of reproducibility in assessing the collected images. Analyses of variance revealed that there were no significant differences between raters for each index (P > .05). The ICC values also indicated excellent reliability (.881-.971) between days and clinicians in all but one of the indices of footprint, arch angle (.689), with good reliability between clinicians. The full-factorial analysis of variance model did not reveal any interaction effects (P > .05), which indicated that indices of footprint were not changing across days and clinicians.

CONCLUSIONS

Scanning technology used in this study demonstrated good intra- and interrater reliability measurements of footprint indices, as demonstrated by high ICC values.

CUMULATIVE EFFECTS OF INTERMITTENT MAXIMAL CONTRACTIONS ON VOLUNTARY ACTIVATION DEFICITS

The purpose of this research was to provide more definitive support for the hypothesis that prolonged muscle activation at high intensities increases voluntary activation deficits. Interpolated twitch responses were evoked during maximal and sub-maximal voluntary contractions of the soleus muscle in 10 college-aged students. Maximal voluntary contractions (MVC), maximal muscle twitches, and interpolated twitch responses were measured before, during, and after fatiguing isometric exercise, five bouts of 20 intermittent MVCs. The relationship between voluntary activation and force was studied by evoking interpolated twitches during sub-maximal voluntary contractions on Day 1 and pre-post fatigue on Day 2. Intraclass reliability coefficients for the MVC, maximal muscle twitch, and interpolated twitch responses were adequate across trials and days (R > or = .80). MVC force and maximal twitch force decreased after the fatiguing exercise bouts by 28% and 32%, respectively (p < .05). Voluntary activation of the fatigue-resistant soleus muscle decreased by 10% after the first five min of maximal exercise with a subsequent decrease of 9% occurring after 25 min of maximal exercise (p < .05). At the end of the experimental session, approximately 30 min after the end of the fatiguing exercise, decreases in 100% MVC force, maximal muscle twitch force, and voluntary activation were still evident: 22%, 23%, and 11%, respectively (p < .05). Post-fatigue, there were also changes in neural strategies for voluntary activation of the soleus muscle at the higher sub-maximal efforts, > or = 70% MVC target levels (p < .05). These data demonstrate the cumulative effects of prolonged exercise on voluntary activation.

Twin pairs discordant for neuropathologically confirmed Lewy body dementia

AIM

Little is known about the concordance rate in twins for dementia with Lewy bodies (DLB). The rate of agreement between clinical and pathological diagnoses for DLB is typically low, necessitating confirmation of the diagnosis neuropathologically.

METHODS

Participants were 17 twin pairs enrolled in the Duke Twins Study of Memory in Aging in which at least one member of the pair had an autopsy confirmed diagnosis of DLB, Alzheimer's disease (AD) with Lewy bodies or frontotemporal dementia with Lewy bodies. The characteristics of those with dementia were assessed and rates of concordance for pathological confirmed dementia were examined.

RESULTS

Four monozygotic twin pairs had a proband with neuropathologically confirmed pure DLB; all remained discordant for dementia for periods up to 16 years or more. Five of 13 pairs in which the proband had AD plus DLB were concordant for dementia but only one pair was concordant for AD plus DLB, while the co-twins in the other four pairs had other types of dementia.

CONCLUSIONS

The present study indicates that even among twins, a diagnosis of DLB in one twin does not predict the same diagnosis in the other twin. Neuropathological discordance in type of dementia among monozygotic pairs hints at environmental or epigenetic factors playing a role in Lewy body pathology.

Motor-evoked potentials recorded from lumbar erector spinae muscles: a study of corticospinal excitability changes associated with spinal manipulation

OBJECTIVE

The purpose of this study was to determine if high-velocity, low-amplitude spinal manipulation (SM) altered the effects of corticospinal excitability on motoneuron activity innervating the paraspinal muscles. In a previous study using transcranial magnetic stimulation (TMS), augmentation of motor-evoked potentials (MEPs) from the gastrocnemius muscle after lumbar SM was reported. To date, there is no known report of the effect of SM on paraspinal muscle excitability.

METHODS

The experimental design was a prospective physiologic evaluation of the effects of SM on corticospinal excitability in asymptomatic subjects. The TMS-induced MEPs were recorded from relaxed lumbar erector spinae muscles of 72 asymptomatic subjects. The MEP amplitudes were evaluated pre-SM and post-SM or conditions involving prethrust positioning and joint loading or control.

RESULTS

There was a transient increase in MEP amplitudes from the paraspinal muscles as a consequence of lumbar SM (F([6,414]) = 8.49; P < .05) without concomitant changes after prethrust positioning and joint loading or in control subjects (P > .05). These data findings were substantiated by a significant condition x time interaction term (F([12,414]) = 2.28; P < .05).

CONCLUSIONS

These data suggest that there is a postsynaptic facilitation of alpha motoneurons and/or corticomotoneurons innervating paraspinal muscles as a consequence of SM. It appears that SM may offer unique sensory input to the excitability of the motor system as compared to prethrust positioning and joint loading and control conditions.

Prevalence of dementia in the United States: the aging, demographics, and memory study

AIM

To estimate the prevalence of Alzheimer's disease (AD) and other dementias in the USA using a nationally representative sample.

METHODS

The Aging, Demographics, and Memory Study sample was composed of 856 individuals aged 71 years and older from the nationally representative Health and Retirement Study (HRS) who were evaluated for dementia using a comprehensive in-home assessment. An expert consensus panel used this information to assign a diagnosis of normal cognition, cognitive impairment but not demented, or dementia (and dementia subtype). Using sampling weights derived from the HRS, we estimated the national prevalence of dementia, AD and vascular dementia by age and gender.

RESULTS

The prevalence of dementia among individuals aged 71 and older was 13.9%, comprising about 3.4 million individuals in the USA in 2002. The corresponding values for AD were 9.7% and 2.4 million individuals. Dementia prevalence increased with age, from 5.0% of those aged 71-79 years to 37.4% of those aged 90 and older.

CONCLUSIONS

Dementia prevalence estimates from this first nationally representative population-based study of dementia in the USA to include subjects from all regions of the country can provide essential information for effective planning for the impending healthcare needs of the large and increasing number of individuals at risk for dementia as our population ages.

Evaluation of the effect of postural perturbation on motoneuronal activity following various methods of lumbar spinal manipulation

BACKGROUND AND CONTEXT

One basic physiologic response to spinal manipulation (SM) is a transient decrease in motoneuronal activity, as assessed by the Hoffmann reflex (H-reflex) technique. However, questions of appropriate control procedures when using the H-reflex technique to study the basic physiologic mechanisms of SM still exist. The identification of appropriate control procedures may allow us to better differentiate among the specific and nonspecific aspects of SM.

PURPOSE

The purpose of the research was to determine the contributions of postural perturbations on the attenuation of motoneuronal activity following spinal manipulative thrusts and spinal joint preload procedures applied to the lumbar spine.

STUDY DESIGN/SETTING

H/M(max) ratios, recorded from the gastrocnemius muscle, were measured before and after lumbar spinal procedures. The experimental designs for the laboratory data collection protocols were repeated measures and between-subjects.

PATIENT SAMPLE

The subjects were asymptomatic, young, healthy volunteers.

OUTCOME MEASURE

H/M(max) ratios recorded from the gastrocnemius muscle.

METHODS

In Experiment 1, the administration of prone lumbar procedures involved either manual assist to more fully shear the lumbar zygapophyseal joints or no manual assist. One set of subjects (n=17) received assisted joint preload force and manipulation, whereas a second set of subjects (n=17) received unassisted joint preload force and manipulation. In a second laboratory experiment, one set of subjects (n=10) received a L5-S1 side-posture SM, whereas a second set of subjects (n=10) were just positioned into side-posture.

RESULTS

There was a H/M(max) ratio attenuation of 18.2% after assisted spinal manipulation, whereas H/M(max) ratio attenuation was only 9.5% after unassisted spinal manipulation. Decreases of H/M(max) ratios by 8.5% and 7.5% were observed after assisted and unassisted joint preload forces, respectively. The amount of H/M(max) ratio attenuation was significantly greater immediately after the L5-S1 SM procedure (28.4%) as compared with a side-posture positioning maneuver (15.3%).

CONCLUSION

SM may provide procedure-specific sensory input that appears to vary, based upon the various types of vertebral loading applied to the lumbar spine.

Modulation of the tibial nerve H-reflex by mechanical stimulation of afferents in the lumbar spine

The purpose of this study was to describe the convergence of afferent discharges from the ligament-muscular system of the lumbar spine to the segmentally-related gastrocnemius muscle. The subjects were 32 healthy, young volunteers recruited from a college student population. Afferent discharges from the ligament-muscular system of the lumbar spine were evoked by manually moving the trunk into either flexion (n = 16) or left lateral bending (n = 16) using a multi-directional adjustable treatment table (Zenith Cox Flexion Table). Using linear potentiometers affixed to the treatment table and interfaced with a computer data acquisition system, manual movements of the table were visually guided to generate passive trunk movements at velocities of 10 degrees, 20 degrees, and 40 degrees per second. Tibial nerve H-reflex responses were recorded from the right gastrocnemius muscle as the trunk approached its end range of motion. Regardless of velocity for the flexion movement, the H/M(Max) ratio significantly decreased from 28.0% to 20.9% (p < .05). During lateral bending, the H/M(Max) ratio significantly decreased from 27.4% to 24.0% at velocities of 10 degrees and 20 degrees per second (p < .05) with a subsequent decrease to 20.5% at a velocity of 40 degrees per second (p < .05). The nature of these decreases in the H/M(Max) ratios across the different velocities during lateral bending significantly departed from linearity (p < .05). These data provide sufficient evidence to suggest that heteronymous conditioning effects from the ligament-muscular system of the lumbar spine during passive trunk movements attenuate alpha motoneuronal activity of the segmentally-related gastrocnemius muscle.

Disrupted spermine homeostasis: a novel mechanism in polyglutamine-mediated aggregation and cell death

Our data suggest a novel mechanism whereby pathological-length polyglutamine (polyQ) proteins promote the spermine synthetic pathway, increasing polyQ-aggregation and cell death. As detected in a cell-free turbidity assay, spermine promotes aggregation of thio-polyQ62 in a dose-dependent manner. Using a stable neuronal cell line expressing pathological-length [polyQ57-yellow fluorescent protein (YFP) (Q57)] or non-pathological-length [polyQ19-YFP (Q19)] polyglutamine protein, we show that multiple steps in the production of polyamines are affected in Q57 cells, suggesting dysfunctional spermine homeostasis. As the building block for spermine synthesis, arginine transport is significantly increased in neuronal cell lines stably expressing Q57. Q57 lines displayed upregulated basal and inducible arginase I activities that were not seen in polyQ19-YFP lines. Normal induction of spermidine/spermine N-acetyltransferase in Q19 lines regulating back-conversion of spermine, thereby reducing spermine levels, however, was not observed in Q57 lines. Pharmacological activation of ornithine decarboxylase (ODC), a key enzyme of the polyamine synthetic pathway, increased cellular aggregates and increased cell death in Q57 cells not observed in Q19 cells. Inhibition of ODC by difluoromethylornithine prevented basal and induced cell death in Q57 cells, demonstrating a central role for polyamines in this process.

Autonomic Nervous System Function Among Individuals With Acute Musculoskeletal Injury

OBJECTIVE

To determine differences in peripheral and cardiovascular autonomic function between individuals with acute musculoskeletal injury (<1 week) and healthy controls.

METHODS

Autonomic cardiovascular modulation, baroreceptor sensitivity, skin conductance, and peripheral skin temperature were obtained in 6 subjects with acute musculoskeletal injury and 6 age- and sex-matched controls. Power spectral analysis was performed on both beat-to-beat R-R intervals and continuous systolic blood pressure (SBP) peaks. Baroreceptor sensitivity was derived using both heart rate and blood pressure spectral analysis components.

RESULTS

The SD of R-R intervals was significantly different for the acute injury group relative to controls (49.8 +/- 10.5 vs 76.8 +/- 12.7 ms; P < .01). Continuous SBP peaks and skin conductance (sympathetic vasomotor and sudomotor indices, respectively) were significantly higher (59.6 +/- 6.7 vs 23.8 +/- 6.4 mm Hg2 /Hz, and 3.87 +/- 1.04 vs 2.19 +/- 0.3 mhos; P < .01, respectively) and baroreceptor sensitivity lower (0.97 +/- 0.07 vs 1.10 +/- 0.08 mm Hg; P < .02) in the acute injury group compared with controls. Regression analysis revealed a significant relationship between skin conductance and continuous SBP peaks (r = 0.75; P < .01).

CONCLUSIONS

These findings suggest that interaction between cutaneous and vasomotor sympathetic neurons in response to acute musculoskeletal injury, reflected as increased afferent input from sensitized nociceptors and other sensory neurons, results in alterations in autonomic function.

Effect of tissue transglutaminase on the solubility of proteins containing expanded polyglutamine repeats

The expansion of a polyglutamine (polyQ) domain in neuronal proteins is the molecular genetic cause of at least eight neurodegenerative diseases. Proteins with a polyQ domain that is greater than 40 Q (Q40) residues form insoluble intranuclear and cytoplasmic inclusions. Expanded polyQ proteins self-associate by non-covalent interactions and become insoluble. They can also be covalently cross-linked by tissue transglutaminase (TTG), a calcium-dependent enzyme present in cells throughout the nervous system. However, it remains unclear whether TTG cross-linking directly contributes to the insolubility of the expanded polyQ proteins. Using an in vitro solubility assay, we found TTG cross-linked Q62 monomers into high molecular weight soluble complexes in a calcium-dependent reaction. Inhibition of TTG cross-linking by primary amine substrates including putrescine and biotinylated pentylamine antagonized TTG's ability to form soluble complexes. In contrast, primary amines (histamine and lysine) that were less effective inhibitors of TTG cross-linking did not inhibit Q62 from becoming insoluble. In summary, TTG can increase the solubility of expanded polyQ proteins by catalyzing intermolecular cross-links. This demonstrates directly that TTG will reduce the ability of expanded polyQ proteins from becoming insoluble. Furthermore, the effectiveness of a primary amine substrate at inhibiting formation of insoluble inclusions may be related to their ability to inhibit intermolecular cross-linking by TTG.

An inhibitor of IkappaB kinase, BMS-345541, blocks endothelial cell adhesion molecule expression and reduces the severity of dextran sulfate sodium-induced colitis in mice

OBJECTIVE

Inflammatory bowel diseases such as ulcerative colitis and Crohn's disease are characterized by chronic relapsing inflammation. The transcription of many of the proteins which mediate the pathogenesis in inflammatory bowel disease (e.g., TNFalpha, ICAM-1, VCAM-1) is NF-kappaB-dependent. IkappaB kinase is critical in transducing the signal-inducible activation of NF-kappaB and, therefore, represents a potentially promising target for the development of novel agents to treat inflammatory bowel disease and other inflammatory diseases.

RESULTS

Here we show that BMS-345541, a highly selective inhibitor of IkappaB kinase, inhibited the TNFalpha-induced expression of both ICAM-1 and VCAM-1 in human umbilical vein endothelial cells at the same concentration range as cytokine expression is inhibited in monocytic cells (IC(50) congruent with 5 microM). Against dextran sulfate sodium-induced colitis in mice, BMS-345541 administered orally at doses of 30 and 100 mg/kg was effective in blocking both clinical and histological endpoints of inflammation and injury.

CONCLUSION

This represents the first example of an inhibitor of IkappaB kinase with anti-inflammatory activity in vivo and indicates that inhibitors of IkB kinase show the promise of being highly efficacious in inflammatory disorders such as inflammatory bowel disease.

Neural adaptations with sport-specific resistance training in highly skilled athletes

The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to record interpolated twitches. The pattern of neural drive was measured by analysing isometric torque-time curves and electromyographic (EMG) characteristics during the performance of rapid isometric contractions at maximal effort. The volume and intensity of training were varied at 4-weekly intervals to systematically emphasize the development of strength, power and motor performance in 14 highly skilled track and field athletes (e.g. discus, hammer, javelin, shot put and weight). Knee extension strength increased significantly by 15% during steady maximal isometric contractions and by 24% during rapid isometric contractions at maximal effort after the 16-week training programme (P < 0.05). Increases in EMG amplitude and rate of EMG activation indicated that improvements to the pattern of neural drive occurred with sport-specific resistance training (P < 0.05). The maximality and pattern of neural drive did not change in the control group.

Genetics of Alzheimer's disease

Alzheimer's disease is the leading cause of dementia in the elderly. Most patients do not have an obvious family history and are classified as sporadic. Genetic factors in early and late-onset Alzheimer's disease are now well documented. This paper reviews the known genetic loci associated with Alzheimer's disease with an emphasis on the role of apolipoprotein E in late-onset familial and sporadic disease. Apolipoprotein E allele 4 is a susceptibility gene that is found in approximately 50% of patients with Alzheimer's disease. Hypotheses about apolipoprotein E function that may lead to Alzheimer's disease are also discussed.

Amino acid sequence requirements of peptides that inhibit polyglutamine-protein aggregation and cell death

Proteins with expanded polyglutamine domains cause eight inherited neurodegenerative diseases including Huntington's disease. In a previous paper, we identified peptides that inhibit polyglutamine protein aggregation and cell death and now describe the amino acid sequence requirements necessary for these activities. The original 11 amino acid polyglutamine (Q) Binding Peptide 1(QBP1; SNWKWWPGIFD) can be shortened to 8 amino acids (WKWWPGIF) without loss of ability to inhibit polyglutamine aggregation. Three determinants are responsible for inhibition: a tryptophan-rich motif (WKWW), a spacer amino acid and the tripeptide GIF. GIF can be replaced by a repeat of the tryptophan-rich motif, but the spacer remains necessary. We also demonstrate concordance between peptide activity in the in vitro assay and a cellular assay of polyglutamine aggregation and cell death. Polyglutamine binding peptides targeted for intracellular delivery by fusion to TAT retain the ability to inhibit polyglutamine aggregation and cell death in transfected COS 7 cells.

Targeting phospholipase A2 for the treatment of inflammatory skin diseases

Due to the problems associated with current treatments for inflammatory disorders of the skin, the pharmaceutical industry has focused on novel ways to treat these disorders. Lipid-derived eicosanoids, which play an important role in the underlying inflammation in psoriasis and atopic dermatitis, can be derived from the phospholipase (PLA)-dependent production of arachidonate. In this review, the characteristics and promise of PLA, inhibitors, which have shown activity in preclinical models of skin inflammation are discussed along with the challenges the field faces in developing clinical candidates.

BMS-229724 is a tight-binding inhibitor of cytosolic phospholipase A2 that acts at the lipid/water interface and possesses anti-inflammatory activity in skin inflammation models

Cytosolic phospholipase A2 (cPLA2) catalyzes the selective release of arachidonic acid from the sn-2 position of phospholipids and is believed to play a key cellular role in the generation of arachidonic acid. BMS-229724 (4-[4-[2-[2-[bis(4-chlorophenyl)methoxy]ethyl-sulfonyl]ethoxy]phenyl]-1,1,1-trifluoro-2-butanone) was found to be a selective inhibitor of cPLA2 (IC50 = 2.8 microM) in that it did not inhibit secreted phospholipase A2 in vitro, nor phospholipase C and phospholipase D in cells. The compound was active in inhibiting arachidonate and eicosanoid production in U937 cells, neutrophils, platelets, monocytes, and mast cells. With a synthetic covesicle substrate system, the dose-dependent inhibition could be defined by kinetic equations describing competitive inhibition at the lipid/water interface. The apparent equilibrium dissociation constant for the inhibitor bound to the enzyme at the interface (K(I)*(app)) was determined to be 1. 10(-5) mol% versus an apparent dissociation constant for the arachidonate-containing phospholipid of 0.35 mol%. The unit of concentration in the interface is mole fraction (or mol%), which is related to the surface concentration of substrate, rather than bulk concentration that has units of molarity. Thus, BMS-229724 represents a novel inhibitor of cPLA2, which partitions into the phospholipid bilayer and competes with phospholipid substrate for the active site. This potent inhibition of the enzyme translated into anti-inflammatory activity when applied topically (5%, w/v) to a phorbol ester-induced chronic inflammation model in mouse ears, inhibiting edema and neutrophil infiltration, as well as prostaglandin and leukotriene levels in the skin. In hairless guinea pigs, BMS-229724 was active orally (10 mg/kg) in a UVB-induced skin erythema model in hairless guinea pigs.

Exercise-induced neuromuscular dysfunction under reflex conditions

The purpose of this research was to describe further the effects of exercise-induced muscle damage on reflex sensitivity. The subjects were eight physically active, but untrained males, between the ages of 18 and 29 years. The effects of eccentric and concentric exercise on patellar tendon reflex responses were determined. The 8 week experiment consisted of two, 5 day, test protocols with a 6 week wash-out period between test protocols. Each 5 day test protocol consisted of the following six test sessions: (1) day 1--baseline, (2) day 2 baseline, (3) day 2--immediate post-exercise, and (4-6) days 3-5: 24, 48, and 72 h post-exercise. On day 2, the subjects made either 100 fatiguing concentric or eccentric isotonic contractions using the right leg at 75% of the corresponding repetition maximum values. During each test session, the electromyogram (EMG) and force-time characteristics of basic and conditioned patellar tendon reflex responses were measured. The reflex amplitudes of basic and conditioned patellar tendon reflex responses were decreased following fatiguing concentric exercise. There were no immediate effects of fatiguing eccentric exercise on the basic and conditioned patellar tendon reflex responses, but the EMG amplitudes of these reflex responses were reduced on the days following eccentric exercise. The amount of conditioned patellar tendon reflex facilitation was decreased following the concentric exercise protocol and at 48 h post-eccentric exercise. Our conditioned reflex data suggest that post-exercise changes to the physiological mechanisms that modulate the recruitment gain of the alpha-motoneuron pool may depend upon the type of fatiguing exercise.

Documented head injury in early adulthood and risk of Alzheimer's disease and other dementias

BACKGROUND

The association between antecedent head injury and AD is inconsistent.

OBJECTIVE

To examine the association between early adult head injury, as documented by military hospital records, and dementia in late life; and to evaluate the interaction between head injury and APOE epsilon4 as risk factors for dementia.

METHODS

The study had a population-based prospective historical cohort design. It included men who were World War II Navy and Marine veterans, and were hospitalized during their military service with a diagnosis of either a nonpenetrating head injury or another unrelated condition. In 1996 to 1997, military medical records were abstracted to document the occurrence and details of closed head injury. The entire sample was then evaluated for dementia and AD using a multistage procedure. There were 548 veterans with head injury and 1228 without head injury who completed all assigned stages of the study. The authors estimated risk of dementia, specifically AD, using proportional hazards models.

RESULTS

Both moderate head injury (hazard ratio [HR] = 2.32; CI = 1.04 to 5.17) and severe head injury (HR = 4.51; CI = 1.77 to 11.47) were associated with increased risk of AD. Results were similar for dementia in general. The results for mild head injury were inconclusive. When the authors stratified by the number of APOE epsilon4 alleles, they observed a nonsignificant trend toward a stronger association between AD and head injury in men with more epsilon4 alleles.

CONCLUSIONS

Moderate and severe head injuries in young men may be associated with increased risk of AD and other dementias in late life. However, the authors cannot exclude the possibility that other unmeasured factors may be influencing this association.

Glyceraldehyde 3-phosphate dehydrogenase abnormality in metabolically stressed Huntington disease fibroblasts

Huntington disease (HD) fibroblasts subjected to stress exhibit an enzyme profile that is different from that exhibited by escapee (unaffected members of families with HD) or control fibroblasts. The specific activity of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in normally cultured HD fibroblasts was not different from that in control and escapee fibroblasts. However, in escapee and control fibroblasts subjected to stress by withholding fresh medium, the specific activity of GAPDH in cells harvested by trypsinization increased greatly 3 weeks after withholding medium ( approximately 8-fold), but the increase was significantly less pronounced ( approximately 3-fold) in the HD fibroblasts. In contrast, only small changes occurred in the specific activity of lipoamide dehydrogenase (LADH) over the same time period, and the values were not significantly different among the three groups at any time point. The specific activity of hexokinase (HK) was significantly higher in the HD fibroblasts at 1-3 weeks after withholding fresh medium than in the escapee/control fibroblasts. Finally, the total yield of fibroblasts per culture flask (as judged by protein content) was significantly greater for the stressed HD fibroblasts than for the escapee and control fibroblasts at 2 and 3 weeks after withholding medium. The present results are in accord with the hypothesis that HD is a disease associated with latent, generalized metabolic abnormalities.

Inhibition of polyglutamine protein aggregation and cell death by novel peptides identified by phage display screening

Proteins with expanded polyglutamine domains cause eight inherited neurodegenerative diseases, including Huntington's, but the molecular mechanism(s) responsible for neuronal degeneration are not yet established. Expanded polyglutamine domain proteins possess properties that distinguish them from the same proteins with shorter glutamine repeats. Unlike proteins with short polyglutamine domains, proteins with expanded polyglutamine domains display unique protein interactions, form intracellular aggregates, and adopt a novel conformation that can be recognized by monoclonal antibodies. Any of these polyglutamine length-dependent properties could be responsible for the pathogenic effects of expanded polyglutamine proteins. To identify peptides that interfere with pathogenic polyglutamine interactions, we screened a combinatorial peptide library expressed on M13 phage pIII protein to identify peptides that preferentially bind pathologic-length polyglutamine domains. We identified six tryptophan-rich peptides that preferentially bind pathologic-length polyglutamine domain proteins. Polyglutamine-binding peptide 1 (QBP1) potently inhibits polyglutamine protein aggregation in an in vitro assay, while a scrambled sequence has no effect on aggregation. QBP1 and a tandem repeat of QBP1 also inhibit aggregation of polyglutamine-yellow fluorescent fusion protein in transfected COS-7 cells. Expression of QBP1 potently inhibits polyglutamine-induced cell death. Selective inhibition of pathologic interactions of expanded polyglutamine domains with themselves or other proteins may be a useful strategy for preventing disease onset or for slowing progression of the polyglutamine repeat diseases.

Polyglutamine domain proteins with expanded repeats bind neurofilament, altering the neurofilament network

Proteins with expanded polyglutamine (polyQ) repeats cause eight inherited neurodegenerative diseases. Nuclear and cytoplasmic polyQ protein is a common feature of these diseases, but its role in cell death remains debatable. Since the neuronal intermediate filament network is composed of neurofilament (NF) and NF abnormalities occur in neurodegenerative diseases, we examined whether pathologic-length polyQ domain proteins interact with NF. We expressed polyQ-green fluorescent fusion proteins (GFP) in a neuroblast cell line, TR1. Pathologic-length polyQ-GFP fusion proteins form large cytoplasmic aggregates surrounded by neurofilament. Immunoisolation of pathologic-length polyQ proteins co-isolated 68 kD NF protein demonstrating molecular interaction. These observations suggest that polyQ interaction with NF is important in the pathogenesis of the polyglutamine repeat diseases.

Peptides corresponding to the N and C termini of IkappaB-alpha, -beta, and -epsilon as probes of the two catalytic subunits of IkappaB kinase, IKK-1 and IKK-2

The signal-inducible phosphorylation of serines 32 and 36 of IkappaB-alpha is the key step in regulating the subsequent ubiquitination and proteolysis of IkappaB-alpha, which then releases NF-kappaB to promote gene transcription. The multisubunit IkappaB kinase (msIKK) responsible for this phosphorylation contains two catalytic subunits, termed IKK-1 and IKK-2. Using recombinant IKK-2, a kinetic pattern consistent with a random, sequential binding mechanism was observed with the use of a peptide corresponding to amino acids 26-42 of IkappaB-alpha. Values of 313 microM, 15.5 microM, and 1.7 min(-1) were obtained for K(peptide), K(ATP), and k(cat), respectively. The value of alpha, a factor by which binding of one substrate changes the dissociation constant for the other substrate, was determined to be 0.2. Interestingly, the recombinant IKK-1 subunit gave similar values for alpha and K(ATP), but values of 1950 microM and 0.016 min(-1) were calculated for K(peptide) and k(cat), respectively. This suggests that the IKK-2 catalytic subunit provides nearly all of the catalytic activity of the msIKK complex with the IKK-1 subunit providing little contribution to catalysis. Using peptides corresponding to different regions of IkappaB-alpha within amino acids 21-47, it was shown that amino acids 31-37 provide most binding interactions (-4.7 kcal/mol of binding free energy) of the full-length IkappaB-alpha (-7.9 kcal/mol) with the IKK-2. This is consistent with the observation that IKK-2 is able to phosphorylate the IkappaB-beta and IkappaB-epsilon proteins, which have consensus phosphorylation sites nearly identical to that of amino acids 31-37 of IkappaB-alpha. A peptide corresponding to amino acids 279-303 in the C-terminal domain of IkappaB-alpha was unable to activate IKK-2 to phosphorylate an N-terminal peptide, which is in contrast to the results observed with the msIKK. Moreover, the IKK-2 catalyzes the phosphorylation of the full-length IkappaB-alpha and the amino acid 26-42 peptide with nearly equal efficiency, while the msIKK catalyzes the phosphorylation of the full-length IkappaB-alpha 25,000 times more efficiently than the 26-42 peptide. Therefore, the C terminus of IkappaB-alpha is important in activating the msIKK through interactions with subunits other than the IKK-2.

Maximal motor unit discharge rates in the quadriceps muscles of older weight lifters

Although the existence of "neural factors" is regularly cited as an important contributor to muscular strength, we have little specific knowledge regarding the existence of such neural factors or how they contribute to the expression of muscular force.

PURPOSE

The present investigation sought to assess maximal motor unit discharge rates in older, highly resistance-trained adults to determine whether maximal motor unit discharge rates might be one such neural contributor to maximal strength production.

METHODS

Subjects consisted of seven well-trained older weight lifters (ages 67-79 yr) and five untrained age-matched older adults. While subjects performed 50 and 100% maximal voluntary knee extensor contractions (MVC), recordings from groups of motor units were obtained from the rectus femoris muscle by using an indwelling electrode. Off-line analysis was performed to identify individual motor unit firing occurrences and to compute maximal motor unit discharge rates.

RESULTS

As expected, knee extension strength in the trained weight lifters (367.0 +/- 72.0 N) was significantly greater than that in the control subjects (299.9 +/- 35.9 N; P < 0.05). Motor unit discharge rates were similar in the two subject groups at the 50% MVC force level (P > 0.05), but maximal (100% MVC) motor unit discharge rate in the weight lifters (23.8 +/- 7.71 pps) was significantly greater than that in the age-matched controls (19.1 +/- 6.29 pps; P < 0.05).

CONCLUSION

Motor unit discharge rates may comprise an important neural factor contributing to maximal strength in older adults.

Managing common behavioral problems in dementia. How to improve quality of life for patients and families

Dementia is the most common reason for nursing home placement, and related behavioral symptoms are the primary factors precipitating the decision. Disruptive behaviors such as depression, sleep disturbance, agitation, aggression, and psychosis can tax family members' abilities to care for a loved one who has reached that stage of the illness. Working with families to institute effective management strategies may help delay institutionalization. In this article, Drs Burke and Morgenlander present a systematic approach to identifying and treating common problems in dementia.