Electrophysiology and 3D-imaging reveal properties of human intracardiac neurons and increased excitability with atrial fibrillation.

Altered autonomic input to the heart plays a major role in atrial fibrillation (AF). Autonomic neurons termed ganglionated plexi (GP) are clustered on the heart surface to provide the last point of neural control of cardiac function. To date the properties of GP neurons in humans are unknown. Here we have addressed this knowledge gap in human GP neuron structure and physiology in patients with and without AF. Human right atrial GP neurons embedded in epicardial adipose tissue were excised during open heart surgery performed on both non-AF and AF patients and then characterised physiologically by whole cell patch clamp techniques. Structural analysis was also performed after fixation at both the single cell and at the entire GP levels via three-dimensional confocal imaging. Human GP neurons were found to exhibit unique properties and structural complexity with branched neurite outgrowth. Significant differences in excitability were revealed between AF and non-AF GP neurons as measured by lower current to induce action potential firing, a reduced occurrence of low action potential firing rates, decreased accommodation and increased synaptic density. Visualisation of entire GPs showed almost all neurons are cholinergic with a small proportion of noradrenergic and dual phenotype neurons. Phenotypic distribution differences occurred with AF including decreased cholinergic and dual phenotype neurons, and increased noradrenergic neurons. These data show both functional and structural differences occur between GP neurons from patients with and without AF, highlighting that cellular plasticity occurs in neural input to the heart that could alter autonomic influence on atrial function. KEY POINTS: The autonomic nervous system plays a critical role in regulating heart rhythm and the initiation of AF; however, the structural and functional properties of human autonomic neurons in the autonomic ganglionated plexi (GP) remain unknown. Here we perform the first whole cell patch clamp electrophysiological and large tissue confocal imaging analysis of these neurons from patients with and without AF. Our data show human GP neurons are functionally and structurally complex. Measurements of action potential kinetics show higher excitability in GP neurons from AF patients as measured by lower current to induce action potential firing, reduced low firing action potential rates, and decreased action potential accommodation. Confocal imaging shows increased synaptic density and noradrenergic phenotypes in patients with AF. Both functional and structural differences occur in GP neurons from patients with AF that could alter autonomic influence on atrial rhythm.

A National Referral Service for Paediatric Brachytherapy: An Evolving Practice and Outcomes Over 13 Years.

AIMS: Most children requiring radiotherapy receive external beam treatment and few have tumours suitable for brachytherapy. No paediatric radiotherapy centre will treat enough patients from its own normal catchment population for expertise in brachytherapy to be developed and sustained. Following discussion and agreement in the national paediatric radiotherapy group, a service for paediatric brachytherapy in the UK has been developed. We report the process that has evolved over more than 10 years, with survival and functional outcome results. MATERIALS AND METHODS: Since 2009, potential patients have been referred to the central paediatric oncology multidisciplinary team meeting, where imaging, pathology and treatment options are discussed. Since 2013, the National Soft Tissue Sarcoma Advisory Panel has also reviewed most patients, with the principal aim of advising on the most suitable primary tumour management for complex patients. Clinical assessment and examination under anaesthetic with biopsies may be undertaken to confirm the appropriateness of brachytherapy, either alone or following conservative surgery. Fractionated high dose rate brachytherapy was delivered to a computed tomography planned volume after implantation of catheters under ultrasound imaging guidance. Since 2019, follow-up has been in a dedicated multidisciplinary clinic. RESULTS: From 2009 to 2021 inclusive, 35 patients (16 female, 19 male, aged 8 months to 17 years 6 months) have been treated. Histology was soft-tissue sarcoma in 33 patients and carcinoma in two. The treated site was pelvic in 31 patients and head and neck in four. With a median follow-up of 5 years, the local control and overall survival rates are 100%. Complications have been few, and functional outcome is good. CONCLUSION: Brachytherapy is effective for selected paediatric patients, resulting in excellent tumour control and good functional results. It is feasible to deliver paediatric brachytherapy at a single centre within a national referral service.

Efficacy and tolerability of celecoxib versus naproxen in patients with osteoarthritis of the knee: a randomized, double-blind, double-dummy trial.

OBJECTIVE: To assess the efficacy and tolerability of celecoxib versus naproxen in patients with osteoarthritis (OA) of the knee. METHODS: This 6-month, randomized, double-blind, double-dummy trial was conducted at 47 centres in the USA. Patients with OA of the knee were randomized to receive 200 mg celecoxib orally once daily or 500 mg naproxen orally twice daily. The primary endpoint was defined as a 20% improvement from baseline to 6 months in Western Ontario and McMaster Universities (WOMAC) OA total score. RESULTS: A total of 586 out of 589 randomized patients received at least one dose of celecoxib (n=294) or naproxen (n=292). The primary endpoint (6-month response rate) was achieved by 52.7% and 49.7% of patients in the celecoxib and naproxen treatment groups, respectively. Significantly fewer discontinuations due to gastrointestinal adverse events occurred in patients receiving celecoxib than in those receiving naproxen (4.1% versus 15.1%, respectively). CONCLUSIONS: Over the 6month study period, celecoxib provided similar improvements in OA symptoms to naproxen. In addition, celecoxib provided better upper gastrointestinal tolerability than naproxen.

Risk factors associated with a decrease ≥2 g/dL in haemoglobin and/or ≥10% haematocrit in osteoarthritis patients taking celecoxib or a nonselective NSAID plus a PPI in a large randomised controlled trial (CONDOR).

BACKGROUND: Nonsteroidal anti-inflammatory drugs are associated with gastrointestinal (GI) damage. The Celecoxib vs. Omeprazole and Diclofenac for At-Risk Osteoarthritis and Rheumatoid Arthritis Patients (CONDOR) trial showed that a haemoglobin drop ≥2 g/dL adjudicated as either of defined or presumed GI origin was the most frequent component/event for the composite GI primary end point. This adverse event is potentially clinically relevant in long-term NSAID treatment. AIM: To define potential risk factors associated with a decrease in haemoglobin/haematocrit. METHODS: Post hoc analysis of the CONDOR trial was conducted in the intention-to-treat population. Clinically significant blood loss was defined as: (i) a haemoglobin drop ≥2 g/dL and/or a haematocrit drop ≥10%; and (ii) blood loss adjudicated as either of defined or presumed GI origin. Fifteen risk factors were evaluated by stepwise logistic regression. Each factor had to be significant at <0.20 α to be included in the model. RESULTS: A total of 64/3774 (1.7%) osteoarthritis (OA) patients had decreased haemoglobin/haematocrit and were adjudicated to the GI endpoint. Significant risk factors, at the 0.20 α level found to be associated with clinically significant blood loss in OA patients included [odds ratio (80% CI)] baseline C-reactive protein (CRP) levels [2.27 (1.46-3.53)], history of gastritis and history of GI intolerance [1.55 (1.06-2.28)], positive Helicobacter pylori at screening [1.54 (1.07-2.22)], increasing age [1.17 (1.04-1.32)] and body mass index [BMI; 1.03 (1.00-1.06)]. CONCLUSIONS: Monitoring for decreases in haemoglobin should be considered for all OA patients and especially those with an increased age, BMI, history of gastritis and GI intolerance, CRP levels >1 mg/dL and/or positive H. pylori status, as this may affect their clinical management.

Haemoglobin decreases in NSAID users over time: an analysis of two large outcome trials.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with clinically significant decreases in haemoglobin dependent and independent of acute bleeding events. AIM: To evaluate the incidence and time to a clinically meaningful decrease in haemoglobin in two double-blind, prospective randomised clinical trials comparing NSAIDs in patients with osteoarthritis (OA) or rheumatoid arthritis (RA). METHODS: In CLASS, patients with OA/RA who were aged ≥ 18 years and required continuous NSAID treatment were included; patients who were Helicobacter pylori positive and/or using aspirin were not excluded. In contrast, in the CONDOR trial, comparing celecoxib alone to diclofenac sustained release (plus omeprazole), patients were aged ≥ 60 years or ≥ 18 years with a history of gastroduodenal ulcer and were H. pylori negative; aspirin or other anti-platelet users were excluded. To make a parallel post hoc analysis we limited our study to 6 months and the populations to only the non-aspirin users in CLASS and those patients receiving either celecoxib or diclofenac. A decrease in haemoglobin of ≥ 2 g/dL defined the primary end point. RESULTS: At 6 months, in the CLASS and CONDOR trials, 1.9% and 2.0% of patients treated with celecoxib and 3.3% and 5.7% of patients treated with diclofenac developed a ≥ 2 g/dL decrease in haemoglobin, respectively, [CLASS: odds ratio (OR) 1.80 (95% confidence interval (CI), 1.22-2.65) and CONDOR: OR 2.93 (95% CI, 2.06-4.15), respectively]. CONCLUSION: IN these two large, independent trials, clinically-meaningful decreases in haemoglobin ≥ 2 g/dL occurred in a relatively similar fashion over time despite differences in trial designs.

The collagenous microstructure of cardiac ventricular trabeculae carneae.

Cardiac ventricular trabeculae are widely used in the study of cardiac muscle function, primarily because their myocytes are axially-aligned. However, their collagen content has not been rigorously determined. In particular, it is unknown whether the content of collagen differs between specimens originating from the left (LV) and right (RV) ventricles and whether, indeed, either corresponds to the collagen content of the ventricular walls themselves. In order to redress this deficit of knowledge, we have used the techniques of fluorescence confocal microscopy and environmental scanning electron microscopy to quantify the proportion of perimysial collagen comprising the cross-sectional area of trabeculae carneae. In trabeculae from both the RV and LV of adult rat hearts, collagen may occupy as little as 1% or as much as 100% of the cross-section. For specimens of dimensions typically used experimentally, there was no difference in average collagen content (6.03 ± 5.14%, n = 33) of preparations from the two ventricles.

Persistence with non-selective NSAIDs and celecoxib among patients with gastroesophageal reflux disease and osteoarthritis or rheumatoid arthritis.

OBJECTIVE: Gastrointestinal (GI) symptoms are common in patients taking nonselective, nonsteroidal anti-inflammatory drugs (nsNSAIDs) and are often a reason for therapy discontinuation. In osteoarthritis (OA) and rheumatoid arthritis (RA) patients requiring pain control, selective COX-2 NSAID use is typically associated with less dyspepsia than is nsNSAID use. Little is known about NSAID tolerance in patients with gastroesophageal reflux disease (GERD). This study assessed nsNSAID and celecoxib prescription patterns, in particular persistence, in OA/RA patients with concomitant diagnosis of GERD. METHODS: An observational study of GERD patients with a diagnosis of OA/RA using two separate databases, the IMS Lifelink Health Plan Claims Database (PharMetrics) and Market Scan Claims Database (Medstat) was conducted. In each database, parallel and separate analyses were performed in adult patients who had their first GERD diagnosis in 2006 and who were subsequently diagnosed with OA or RA in the same year. From this subset of patients, celecoxib-naïve and nsNSAID-naïve cohorts were identified and patients were selected. Patients with pre-existing GI conditions were excluded from the study. Persistence, measured as time to discontinuation, was evaluated by Kaplan-Meier survival curves and Cox proportional hazards models. Reasons for discontinuations were not available in these databases. RESULTS: Fewer patients discontinued celecoxib as compared to nsNSAIDs during the 60 days of the first prescription and throughout the entire follow-up period. After adjusting for baseline characteristics, celecoxib patients still had significantly decreased risk of discontinuation as compared to nsNSAID patients (p < 0.0001). Replication of these observations in two separate, large patient databases increases the confidence in this study's conclusion. LIMITATIONS: Limitations include those inherent to claims data analyses and retrospective review, e.g. these data do not provide clinical information related to reasons for medication discontinuation. CONCLUSION: In patients with concomitant GERD and OA or RA who require anti-inflammatory treatment, significantly more patients treated with celecoxib were persistent with their treatment than were patients treated with nsNSAIDs.

Three-dimensional high-resolution reconstruction of the human gastro-oesophageal junction.

The aim of this study was to obtain detailed information regarding the three-dimensional structure of the gastro-oesophageal region, and, in particular, the fiber orientation of the different muscle layers of the junction. This was achieved by a study of an en bloc resection of the gastro-oesophageal junction (GOJ) harvested from a human cadaver. The excised tissue block was suspended in a cage to preserve anatomical relationships, fixed in formalin and embedded in wax. The tissue block was then processed by a custom-built extended-volume imaging system to obtain the microstructural information using a digital camera which acquires images at a resolution of 8.2 microm/pixel. The top surface of the tissue block was sequentially stained and imaged. At each step, the imaged surface was milled off at a depth of 50 microm. The processing of the tissue block resulted in 650 images covering a length of 32.25 mm of the GOJ. Structures, including the different muscle and fascial layers, were then traced out from the cross-sectional images using color thresholding. The traced regions were then aligned and assembled to provide a three-dimensional representation of the GOJ. The result is the detailed three-dimensional microstructural anatomy of the GOJ represented in a new way. The next stage will be to integrate key physiological events, including peristalsis and relaxation, into this model using mathematical modeling to allow accurate visual tools for training health professionals and patients.

Water quality modeling of fertilizer management impacts on nitrate losses in tile drains at the field scale.

Nitrate losses from subsurface tile drained row cropland in the Upper Midwest U.S. contribute to hypoxia in the Gulf of Mexico. Strategies are needed to reduce nitrate losses to the Mississippi River. This paper evaluates the effect of fertilizer rate and timing on nitrate losses in two (East and West) commercial row crop fields located in south-central Minnesota. The Agricultural Drainage and Pesticide Transport (ADAPT) model was calibrated and validated for monthly subsurface tile drain flow and nitrate losses for a period of 1999-2003. Good agreement was found between observed and predicted tile drain flow and nitrate losses during the calibration period, with Nash-Sutcliffe modeling efficiencies of 0.75 and 0.56, respectively. Better agreements were observed for the validation period. The calibrated model was then used to evaluate the effects of rate and timing of fertilizer application on nitrate losses with a 50-yr climatic record (1954-2003). Significant reductions in nitrate losses were predicted by reducing fertilizer application rates and changing timing. A 13% reduction in nitrate losses was predicted when fall fertilizer application rate was reduced from 180 to 123 kg/ha. A further 9% reduction in nitrate losses can be achieved when switching from fall to spring application. Larger reductions in nitrate losses would require changes in fertilizer rate and timing, as well as other practices such as changing tile drain spacings and/or depths, fall cover cropping, or conversion of crop land to pasture.

Automated extended volume imaging of tissue using confocal and optical microscopy.

Conventional histologic techniques cannot readily be used for 3D reconstruction of large tissue volumes. We have developed an imaging rig which supports both confocal and light microscopy, and utilizes a surface imaging approach to serially image embedded tissue blocks while maintaining alignment and registration of the image series.

Rapid construction of a patient-specific torso model from 3D ultrasound for non-invasive imaging of cardiac electrophysiology.

One of the main limitations in using inverse methods for non-invasively imaging cardiac electrical activity in a clinical setting is the difficulty in readily obtaining high-quality data sets to reconstruct accurately a patient-specific geometric model of the heart and torso. This issue was addressed by investigation into the feasibility of using a pseudo-3D ultrasound system and a hand-held laser scanner to reconstruct such a model. This information was collected in under 20 min prior to a catheter ablation or pacemaker study in the electrophysiology laboratory. Using the models created from these data, different activation field maps were computed using several different inverse methods. These were independently validated by comparison of the earliest site of activation with the physical location of the pacing electrodes, as determined from orthogonal fluoroscopy images. With an estimated average geometric error of approximately 8 mm, it was also possible to reconstruct the site of initial activation to within 17.3 mm and obtain a quantitatively realistic activation sequence. The study demonstrates that it is possible rapidly to construct a geometric model that can then be used non-invasively to reconstruct an activation field map of the heart.

Construction of patient specific geometries suitable for the inverse problem of electrocardiography.

The ability to accurately construct a geometric representation of the heart and torso is a critical component for electrocardiographic inverse algorithms. Typically geometric models have been constructed using data acquired from imaging modalities such as MRI and CT. We propose a system where the torso surface geometry is obtained using a laser scanning device and the heart geometry is obtained using three-dimensional ultrasound.

Constructing a tissue-specific model of ventricular microstructure.

Simulations of cardiac electrical activity are generally computed in idealized or generic domains. We have developed a semi-automated technique for imaging an extended volume of cardiac ventricular tissue at a resolution of approximately 1 microm, and constructing from those images a geometric and structural model with 10 microm resolution suitable for solving the bidomain equations. This technique enables experimental modeling and computer simulation to be integrated by constructing a tissue-specific structural model in less than one week. We demonstrate the use of this procedure applied to a sample of rat ventricle.

Three monosymptomatic hypochondriacal syndromes in dermatology.

Monosymptomatic hypochondriacal delusional syndrome (MHD) is the term applied to a disease characterized by a single prominent belief that there is a disease process present despite evidence to the contrary. Three forms of the syndrome and their diagnoses and treatment will be discussed.

Report of the AAN Task Force on access to health care: the effect of no personal health insurance on health care for people with neurologic disorders. Task Force on Access to Health Care of the American Academy of Neurology.

Access to medical care is limited for people with no health insurance. In the United States, an estimated 31 to 41 million people under age 65 have no health insurance. Among the uninsured, an estimated 340,000 new cases of neurologic disorders occur annually. The Task Force on Access to Health Care of the Academy analyzed data from four nationwide health surveys to describe the national population of people with neurologic disorders (PWND) by insurance status and to examine access to care, utilization of services, and expenses for health care of PWND. Health insurance status significantly affected access to and utilization of health care services. Compared with insured PWND, the uninsured less often had a usual source of medical care, saw a particular doctor, or visited a neurologist. The uninsured had fewer doctor's office visits and fewer hospital admissions than privately insured PWND. In the doctor's office they got fewer tests, fewer referrals for therapies, but more medications. In the hospital they received more diagnostic and therapeutic procedures overall, but those with cerebrovascular disease received fewer angiograms and endarterectomies. National health care reform may improve access to care for PWND if they are equitably included in the new systems. However, neurologists should assertively advocate for the needs of PWND to have adequate insurance and appropriate access to neurologic consultations, neurologic tests, and treatments.

Cough, exertional, and other miscellaneous headaches.

We have discussed several miscellaneous headache disorders not associated with structural brain disease. The first group included those headaches provoked by "exertional" triggers in various forms. These include benign cough headache, BEH, and headache associated with sexual activity. The IHS diagnostic criteria were discussed. Benign exertional headache and cough headache were discussed together because of their substantial similarities. In general, BEH is characterized by severe, short-lived pain after coughing, sneezing, lifting a burden, sexual activity, or other similar brief effort. Structural disease of the brain or skull was the most important differential diagnosis for these disorders, with posterior fossa mass lesions being identified as the most common organic etiology. Magnetic resonance imaging with special attention to the posterior fossa and foramen magnum is the preferred method for evaluating these patients. Indomethacin is the treatment of choice. The headache associated with sexual activity is dull in the early phases of sexual excitement and becomes intense at orgasm. This headache is unpredictable in occurrence. Like BEH, the headache associated with sexual activity can be a manifestation of structural disease. Subarachnoid hemorrhage must be excluded, by CT scanning and CSF examination, in patients with the sexual headache. Benign headache associated with sexual activity has been successfully treated with indomethacin and beta-blockers. The second miscellaneous group of headache disorders includes those provoked by eating something cold or food additives, and by environmental stimuli. Idiopathic stabbing headache does not have a known trigger and appears frequently in migraineurs. Its occurrence may also herald the termination of an attack of cluster headache. Indomethacin treatment provides significant relief. Three headaches triggered by substances that are eaten were reviewed: ingestion of a cold stimulus, nitrate/nitrite-induced headache, and MSG-induced headache. For the most part, avoidance of these stimuli can prevent the associated headache. Lastly, we reviewed headache provoked by high altitude and hypoxia. The headache is part of the syndrome of AMS during its early or benign stage and the later malignant stage of HACE. The pain can be exacerbated by exercise. The best treatment is prevention via slow ascent and avoidance of respiratory depressants. Acetazolamide and dexamethasone have proved useful in preventing this syndrome.