Focal magnetic coil stimulation reveals motor cortical system reorganized in humans after traumatic quadriplegia

A figure of ‘8’ magnetic coil (MC) was used to stimulate focally the motor cortex of two adult, traumatic quadriplegics and three normal adults. The two patients were injured approximately 2 years previously and had intensive physiotherapy, including biofeedback training of biceps and deltoid muscles, respectively, which were the most caudal muscle spared. The focal MC elicited compound motor action potentials (CMAPs) from these muscles from a much wider area of scalp than in the normal subjects. Latency of biceps and deltoid CMAPs were inversely related to CMAP amplitude. A reorganization of the motor cortical projection system is inferred, in which areas normally eliciting digit movements instead activate muscles in quadriplegics just above the spinal level. The reorganization applies also to the central sense of movement normally elicited by focal frontal cortex stimulation. Possible mechanisms of the reorganization and an implication for rehabilitation are discussed.     

Prediction of Drug Release from Hydroxypropyl Methylcellulose (HPMC) Matrices: Effect of Polymer Concentration

Pharmaceutical Research -     

Directly Observed Therapy for Treatment Completion of Pulmonary Tuberculosis: Consensus Statement of the Public Health Tuberculosis Guidelines Panel

C. Patrick Chaulk, MD, MPH; Vahe A. Kazandjian, PhD, MPH; for the Public Health Tuberculosis Guidelines Panel

JAMA. 1998;279:943-948.

Objective.— To evaluate evidence on the relative effectiveness of directly observed therapy in achieving treatment completion for pulmonary tuberculosis.

Participants.— A panel of 11 practitioners representing the public health, behavioral, and clinical management of tuberculosis was convened by the Council on Linkages Between Academia and Public Health Practice in 1995 to develop public health guidelines for tuberculosis treatment completion.

Evidence.— English-language articles identified through MEDLINE (1966 to August 1, 1996) with original data on directly observed therapy, supervised therapy, compliance, treatment completion, case management, and treatment adherence for tuberculosis.

Consensus Process.— Each eligible article underwent structured review by at least 2 panel members for study design, sample size, evaluation methods, and treatment completion as the primary outcome. The full panel was convened twice, with intercurrent small group meetings, conference calls, and summary workshop to review findings. Recommendations made through this process were drafted by the panel chair and circulated twice for additional panel comments.

Conclusions.— Treatment completion rates for pulmonary tuberculosis are most likely to exceed 90%, as recommended by the Centers for Disease Control and Prevention, when treatment is based on a patient-centered approach using directly observed therapy with multiple enablers and enhancers. Other less intensive interventions, including nonsupervised strategies and modified approaches to directly observed therapy, are unlikely to achieve this recommended treatment completion goal. Directly observed therapy also appears to be cost-effective compared with self-administered therapy, although data on cost-effectiveness are limited.

     

Spatiotemporal dynamics of early spatial and category-specific attentional modulations

Different attention types select and focus brain resources on relevant sensory information. However, key questions remain unresolved: when and where cortical visual processing is first modulated by different types of attention? How do such modulatory effects spread thereafter? Here, we address these issues for spatial and category-specific types of attention using magnetoencephalography (MEG). First we identified the dynamics of visual attention-independent sensory processing to serve as a baseline framework for the attentional modulations of interest. We found that visual information is processed through the entire hierarchy of visual areas in at least two phases, in the 40-130 ms and 130-230 ms periods respectively. Spatial attention modulations were identified from the beginning of the initial stimulus-evoked response in the primary visual cortex ~70 ms post-stimulus. Category-specific attention modulated face processing beginning from the first face-specific response in high-level object-related areas ~100 ms post-stimulus, substantially earlier than previously reported for face-directed attention. Thus both attention types modulated responses during the first processing phase, beginning at the earliest brain area capable of coding the attentional target. Thereafter attentional effects propagated through the visual cortex together with the stimulus-evoked activity. Category-specific attention did not affect the first-phase responses in low-level strongly retinotopic visual areas, while the second-phase responses were enhanced when the stimulus was the response target and reduced when it was a distractor. Responses during both phases in high-level object-related areas were enhanced by category-specific attention independent of their target/distractor status. Spatial attention effects were stronger in low-level areas, whereas category-specific attention effects were stronger in high-level object-related areas.     

The refractory period of fast conducting corticospinal tract axons in man and its implications for intraoperative monitoring of motor evoked potentials.

OBJECTIVE: To determine the absolute and relative refractory period (RRP) of fast conducting axons of the corticospinal tract in response to paired high intensity (HI or supramaximal) and moderate intensity (MI or submaximal) electrical stimuli. The importance of the refractory period of fast conducting corticospinal tract axons has to be considered if repetitive transcranial electrical stimulation (TES) is to be effective for eliciting motor evoked potentials (MEPs) intraoperatively. METHODS: Direct (D) waves were recorded from the epidural space of the spinal cord in 14 patients, undergoing surgical correction of spinal deformities. To assess the absolute and RRPs of the corticospinal tract, paired transcranial electrical stimuli at interstimulus intervals (ISI) from 0.7 to 4.1 ms were applied. Recovery of conditioned D wave at short (2 ms) and long (4 ms) ISI was correlated with muscle MEP threshold. The refractory period for peripheral nerve was tested in comparison to that for the corticospinal tract. In four healthy subjects sensory nerve action potentials of the median nerve were studied after stimulation with paired stimuli. RESULTS: HI TES revealed a mean duration of 0.82 ms for the absolute refractory period of the corticospinal tract, while MI stimulation resulted in a mean refractory period duration of 1.47 ms. Stimuli of HI produced faster recovery of D wave amplitude during the RRP. Furthermore, short trains of transcranial electrical stimuli did not elicit MEPs when D wave showed incomplete recovery. A similar influence of stimulus intensity on recovery time was found for the refractory period of peripheral nerve. CONCLUSIONS: The recovery of D wave amplitude is dependent upon stimulus intensity. High intensity produces fast recovery. This is an important factor for the generation of MEPs. When HI TES is used to elicit MEPs, short and long ISIs are equally effective. When MI TES is used to elicit MEPs, only a long ISI of 4 ms is effective.     

Total reconstruction of the mitral valve with autopericardium: anatomical study

Mitral valve repair has several advantages over prosthetic valve replacement. A new technique of total reconstruction of the mitral valve with autologous pericardium is described. The native mitral valve leaflets and chordae were excised from 10 human cadaver hearts, in the same way as for prosthetic valve replacement. The dimensions of the physiologically normal mitral valve were used to calculate the parameters for tailoring a corresponding new valve. Autologous pericardium was fixed in 0.625% glutaraldehyde solution for 10 minutes. The calculated parameters of the mitral valve were marked on the pericardium. The new valve was fashioned and inserted in the native valve position. Hydraulic probes showed good competence in all 10 reconstructed mitral valves. This method might be a good alternative to prosthetic valve replacement.     

A proposed adaptation of the EFQM fundamental concepts of excellence to health care based on the PATH framework.

OBJECTIVE: The use of the European Foundation for Quality Management (EFQM) Model in health care has found that this model is useful in promoting quality improvement, but its use in health care organizations is challenging because being a generic model, it does not cover the clinical aspects or the specifics of this field. For that reason, this article aims to bring the EFQM fundamental concepts of excellence closer to health care, using a specific model as a reference to this field: the Performance Assessment Tool for quality improvement in Hospitals (PATH) conceptual framework, developed by the WHO Regional Office for Europe. METHOD: A content analysis was performed to independently identify the contents that defined the elements of both frameworks. Then, using defined criteria, two independent researchers compared the contents of the elements of both frameworks. The elements from both frameworks that were equivalent were aggregated. Several experts discussed the aspects with discrepancies between the two comparisons. Finally, the EFQM framework is adapted to health care by adding to those aggregated elements the aspects that were exclusive from one of the models. RESULTS: The EFQM framework has many correspondences to a health care-specific framework. The EFQM-health care-adapted framework has eight quality dimensions, two of them (customer focus and safety) being overlapped with the other six (staff, results orientation, responsive governance, leadership and constancy of purpose, clinical effectiveness, and partnership development). This model also has two methodological dimensions (management by processes and facts and continuous learning; improvement and innovation). CONCLUSION: This adapted model seems useful for health care organizations, but it needs to be further used to corroborate this preliminary finding.