Establishing between-session reliability of TMS-conditioned soleus H-reflexes.

Transcranial magnetic stimulation (TMS) of the primary motor cortex (M1) can be used to evaluate descending corticomotor influences on spinal reflex excitability through modulation of the Hoffman reflex (H-reflex). The purpose of this study was to characterize between-session reliability of cortical, spinal, and cortical-conditioned spinal excitability measures collected from the soleus muscle. Thirteen able-bodied young adult participants were tested over four sessions. Intraclass correlation coefficients were calculated to quantify between-session reliability of active motor threshold (AMT), unconditioned H-reflexes (expressed as a percentage of Mmax), and conditioned H-reflexes using short-latency facilitation (SLF) and long-latency facilitation (LLF). Pearson correlation coefficients were calculated to assess associations between H-reflex facilitation and unconditioned H-reflex amplitude. Between-session reliability for SLF (ICC=0.71) was higher than for LLF (ICC=0.45), was excellent for AMT (ICC=0.95), and was moderate for unconditioned H-reflexes (ICC=0.63). Our results suggest moderate-to-good reliability of SLF and LLF to evaluate cortical influences on spinal reflex excitability across multiple testing sessions in able-bodied individuals.

Understanding the role of the primary somatosensory cortex: Opportunities for rehabilitation.

Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes.

Development of patient centric virtual organizations (PCVOs) in clinical environment for patient information management.

A novel Virtual Organization framework which incorporates wireless technology support is presented in the research work. The Virtual Organization is designed for a clinical environment to provide better patient information management and enhanced collaborative working of multidisciplinary care teams. The analysis studies the current clinical practices and looks at the general patient information resource structure currently in use for patient care. Based on this problem analysis and current requirements of the multi-disciplinary care team members, we propose a generic and sustainable Patient Centric Virtual Organization (PCVO) framework to complement the functionality of the existing infrastructure by incorporating wireless technologies support for improved patient information provision at the point of care. The preliminary results of the study identify and classify the specific point of care tasks suited to appropriate information resources needed by the care team members. This paper concentrates on the patient information management aspects brought in by incorporating wireless technologies at the point of care using patient information resources in a decentralized and distributed computing environment. This applied research is carried out in the secondary and tertiary care sector in the cancer domain. For the analysis and results of the pilot project, we have used a case study of a local NHS Cancer Hospital.

Using artificial intelligence to bring evidence-based medicine a step closer to making the individual difference.

The vision of evidence-based medicine is that of experienced clinicians systematically using the best research evidence to meet the individual patient's needs. This vision remains distant from clinical reality, as no complete methodology exists to apply objective, population-based research evidence to the needs of an individual real-world patient. We describe an approach, based on techniques from machine learning, to bridge this gap between evidence and individual patients in oncology. We examine existing proposals for tackling this gap and the relative benefits and challenges of our proposed, k-nearest-neighbour-based, approach.

Endovascular treatment of extra-cranial carotid artery bifurcation disease.

Over the past decade, carotid stenting with embolic protection has emerged as a viable alternative to carotid endarterectomy in patients with severe extra-cranial bifurcation atherosclerotic disease. Several patient subsets -- high surgical risk, symptomatic, asymptomatic, etc.,-- have and are being studied in multi-center trials throughout Europe and the United States. Results of trials to date suggest that, in the high surgical risk cohorts, carotid stenting is statistically on par with endarterectomy with strong trends toward superiority in at least 2 trials SAPPHIRE and ARCHeR. In addition to these important ongoing clinical studies, physician training, reimbursement, and registry development still are in the early stages of evolution in the US.

Safety, efficacy, and durability of carotid artery stenting for restenosis following carotid endarterectomy: a multicenter study.

PURPOSE: To present the results of a multicenter registry established to collect data on carotid stent procedures in patients with restenosis following carotid endarterectomy. METHODS: The procedural details, outcomes, and late follow-up results were collected from 14 centers in the United States. Thirty-day and late stroke and death rates were analyzed. RESULTS: Three hundred and thirty-eight patients (201 men; 71 +/- 8 years) underwent carotid stenting in 358 arteries. The average duration from carotid endarterectomy was 5.5 +/- 7.3 years. Sixty-one percent of the patients were asymptomatic. The overall 30-day stroke and death rate was 3.7%. The minor stroke rate was 1.7% (6/358), and the major nonfatal stroke rate was 0.8% (3/358). The fatal stroke rate was 0.3% (1/358), and the nonstroke-related death rate was 0.9% (3/338). There was 1 (0.3%) fatal and 1 (0.3%) nonfatal stroke during the follow-up period. The overall 3-year rate of freedom from all fatal and nonfatal strokes was 96% +/- 1% (+/- SE). CONCLUSIONS: Carotid artery stenting can be performed in patients with restenosis following carotid endarterectomy with 30-day complication rates comparable to those of most published studies on repeat carotid endarterectomy. Results of late follow-up suggest that this technique is durable and efficacious.

Ultra-fast track hospital discharge using conventional cardiac surgical techniques.

BACKGROUND: Recent introduction of minimally invasive adult cardiac surgical techniques has emphasized the advantage of early hospital discharge. However, we chose an alternative approach to determine the safety, efficacy, and feasibility of ultra-fast track protocols while retaining both standard surgical exposure (median sternotomy) and conventional cardiac surgical techniques (hypothermia, cardiopulmonary bypass with cardiac arrest, and optimal myocardial protection). METHODS: From September 1995 to January 1998, a total of 258 consecutive patients underwent cardiac procedures by a single surgeon. Acceleration of clinical pathways was used to initiate earlier discharges. Stringent postdischarge follow-up was implemented. Prospectively entered data were then analyzed retrospectively. RESULTS: A variety of isolated as well as combined coronary and valve procedures were performed. Of the 258 patients operated on during this entire study period, a total of 144 patients (56%) were discharged within postoperative days 1 to 4 (ultra-fast track discharge). Over the past 12 months, this incidence increased to 70% (76 of 108 patients). Approximately 50% of these patients were operated on urgently or emergently. To date, there have been no deaths in this ultra-fast track group. There were eight brief readmissions, of which one was for rewiring of a noninfected sternal dehiscence, and the remaining were for cardiac diagnostic studies or a noncardiac problem altogether. CONCLUSIONS: Conventional cardiac operation can allow ultrafast hospital discharges while retaining the advantage of time-tested techniques and providing wider application without requiring new or additional training or equipment.

Unsuccessful emergency medical resuscitation--are continued efforts in the emergency department justified?

BACKGROUND: The majority of attempts to resuscitate victims of prehospital cardiopulmonary arrest are unsuccessful, and patients are frequently transported to the emergency department for further resuscitation efforts. We evaluated the efficacy and costs of continued hospital resuscitation for patients in whom resuscitation efforts outside the hospital have failed. METHODS: We reviewed the records of 185 patients presenting to our emergency department after an initially unsuccessful, but ongoing, resuscitation for a prehospital arrest (cardiac, respiratory, or both) by an emergency medical team. Prehospital and hospital characteristics of treatment for the arrest were identified, and the patients' outcomes in the emergency room were ascertained. The hospital course and the hospital costs for the patients who were revived were determined. RESULTS: Over a 19-month period, only 16 of the 185 patients (9 percent) were successfully resuscitated in the emergency department and admitted to the hospital. A shorter duration of prehospital resuscitation was the only characteristic of the resuscitation associated with an improved outcome in the emergency department. No patient survived until hospital discharge, and all but one were comatose throughout hospitalization. The mean stay in the hospital was 12.6 days (range, 1 to 132), with an average of 2.3 days (range, 1 to 11) in an intensive care unit. The total hospital cost for the 16 patients admitted was $180,908 (range per patient, $1,984 to $95,144). CONCLUSIONS: In general, continued resuscitation efforts in the emergency department for victims of cardiopulmonary arrest in whom prehospital resuscitation has failed are not worthwhile, and they consume precious institutional and economic resources without gain.

Comparison of 99mTc-teboroxime with thallium for myocardial imaging in the presence of a coronary artery stenosis.

BACKGROUND: This study tested the hypotheses in the setting of a coronary artery stenosis that 1) planar 99mTc-teboroxime myocardial scans are capable of providing a good estimate of relative coronary flow reserve, and 2) delayed washout of the tracer from the myocardium is a marker of reduced myocardial blood flow and, in certain cases, myocardial ischemia. METHODS AND RESULTS: Experiments were conducted in eight closed-chest domestic swine prepared with an artificial stenosis that reduced diameter of the left anterior descending coronary artery by 80%. Measurements of hemodynamics, regional myocardial blood flow, oxygen, and lactate metabolism were made 1) at baseline, 2) after 5 minutes of intravenous infusion of adenosine and neosynephrine ("stress"), and 3) at recovery 2 hours after discontinuing the adenosine/neosynephrine infusion. Simultaneous intravenous injection of teboroxime (approximately 9 mCi) and thallium (approximately 3.5 mCi) was made at peak stress, and serial planar teboroxime imaging began 1-2 minutes later. Scans were made in dynamic mode for 30 seconds each for 7 minutes after which a stress thallium scan (7 minutes acquisition) was obtained. A redistribution thallium scan was made 2 hours later after which a repeat teboroxime injection followed by serial imaging for 7 minutes was performed. The animal was then killed, and the heart removed for determination of microsphere activity. Under baseline conditions, transmural myocardial blood flow (ml/min/g) distal to the stenosis (1.06 +/- 0.17) was reduced (p less than 0.01) compared with the normally perfused circumflex zone (1.50 +/- 0.31). In response to intravenous infusion of adenosine/neosynephrine, flow increased (p less than 0.01) compared with baseline in both distal (2.00 +/- 0.84) and circumflex (4.67 +/- 1.55) zones. However, the distal : circumflex flow declined (0.45 +/- 0.17) compared with baseline (0.73 +/- 0.17; p less than 0.01). Two hours later flow had returned to baseline levels in both zones, and lactate production during stress (-41.7 +/- 37.5 mumol/min/100 g) had reverted to consumption (13.6 +/- 7.7; p less than 0.05). Analysis of stress teboroxime scans demonstrated 1) an increase (p less than 0.01) in the ischemic : normal zone (IZ:NZ) count between 30-second (0.50 +/- 0.14) and 7-minute scans (0.61 +/- 0.11); 2) a good correlation between the 30-second scan IZ:NZ count and the stress distal : circumflex flow (0.45 +/- 0.17; r = 0.74; p less than 0.05; slope = 0.90; intercept = 0); and 3) a close correlation between the IZ:NZ count of the 7-minute scan (0.61 +/- 0.11) and the recovery distal : circumflex flow (0.69 +/- 0.21; r = 0.89; p less than 0.01). The IZ:NZ count also increased (p less than 0.01) between 30-second (0.65 +/- 0.15) and 7-minute (0.72 +/- 0.14) scans following rest injection of teboroxime. As anticipated, serial thallium scans demonstrated evidence of redistribution between stress (IZ:NZ count = 0.62 +/- 0.08) and recovery (IZ:NZ count = 0.75 +/- 0.06; p less than 0.01) time points. The stress thallium scan IZ:NZ, however, was greater than that of the 30-second teboroxime scan as well as that of the stress distal : circumflex flow. CONCLUSIONS: Accordingly, the data indicate that 1) myocardial imaging with 99mTc-teboroxime is valuable in the noninvasive assessment of relative coronary flow reserve and that 2) delayed washout of the tracer from the myocardium reflects reduced myocardial blood flow and, under conditions comparable to those of the present study, may be a marker of myocardial ischemia.

Specificity of monoclonal antibodies reactive with Fusobacterium nucleatum: effect of formalin fixation.

Monoclonal antibody specific for Fusobacterium nucleatum was reacted with untreated and formalin fixed F. nucleatum cells by an enzyme-linked immunosorbent assay (ELISA) and by indirect immunofluorescence. Treatment of bacterial cells with formalin destroyed the antigenic determinant responsible for reactivity with this monoclonal antibody in both assays. Formalin fixation had no effect on hemagglutination activity (HA) of F. nucleatum cells or reactivity with polyvalent rabbit antiserum in double diffusion in agar. Scanning electron microscopy demonstrated that formalin fixation did not affect binding of F. nucleatum cells to microtiter plates. When developing monoclonal antibodies to be used as diagnostic reagents, the antigenic form utilized for immunization should be identical to the antigenic form which will eventually be used in the diagnostic assay.

The electron microscopy of bacteriophage-like particles in dental plaque.

The morphology of bacteriophage-like particles contained in samples of dental plaque is described. The phage-like particles were observed within fusiform-shaped bacteria and in clumps between bacteria. The particles were hexagonal in cross section, approximately 1,100 nm in diameter and contained an electron-dense core. In areas of cell lysis tail forms were observed both free and in association with the particles. Occasional particles were attached to bacterial cell walls by means of shortened tailpieces.