Investigation of a whole-body receiver coil operating at liquid nitrogen temperatures

This communication describes the design and application of a receiver coil operating at liquid nitrogen temperature and intended as a surface coil in a whole-body imager. Its particular application is seen as the external receiver for parasitic internal or implanted detectors.     

Portion Sizes in Dietary Assessment: Issues and Policy Implications

Accurate estimates of energy and nutrient intake of individuals and populations are contingent on the reliability of information obtained about food intake, food composition, and portion size. This article reviews issues related to the definition, determination, and use of portion sizes in dietary assessment and public education.     

Physiologic and pharmacologic approaches to spasticity

The term spasticity is used to describe many relatively unrelated syndromes and, because they share few common pathophysiologic mechanisms, it is not possible to define the physiology or pharmacology of spasticity. In patients with spastic paresis, it is the latter negative symptom (rather than the spasticity) that accounts for almost all the functional disability. Clinical neurophysiologic techniques are useful for categorization of patients with clinically identical syndromes into subgroups which respond to different therapies. Fusimotor or spindle primary afferent hyperactivity have not been demonstrated in spastic patients; reduction in central inhibitory mechanisms probably accounts for spastic hyper-reflexia. Increased passive muscle stiffness may also be clinically significant. Therapies for spasticity include elimination of causative or enhancing factors, frequent muscle stretching, surgical approaches and chemotherapy. The latter includes dantrolene (which weakens muscles), baclofen (particularly useful for reduction of flexor spasms and flexor dystonia in patients with spinal lesions) and diazepam.     

Altered gastric emptying in the head-injured patient: relationship to feeding intolerance

Most patients with moderate to severe head injury initially do not tolerate enteral feedings postinjury. This intolerance is more prolonged than that found in patients suffering other types of trauma. The authors prospectively evaluated 12 patients with moderate to severe head injury (Glasgow Coma Scale score between 4 and 10) throughout their hospitalization for liquid gastric emptying as a possible mechanism for intolerance to enteral feeding. During Week 1, the majority of patients displayed a delay in gastric emptying. Patients also displayed an abnormal biphasic response (gastric emptying faster than normal during the early stage but prolonged later). By Week 2, many patients still had delayed and abnormal biphasic responses to gastric emptying. By Week 3, an improvement was observed with the majority of patients exhibiting rapid gastric emptying, but delays and abnormal biphasic responses were still seen. Patients who initially had rapid or normal gastric emptying tolerated full-strength full-rate feedings significantly earlier compared with those who experienced delayed gastric emptying (8.5 +/- 0.5 days vs. 13.7 +/- 3.2 days, p less than 0.001). All patients tolerated full-strength full-rate feedings by Day 16 postinjury (range 7 to 16 days) except the two patients who displayed delayed gastric emptying for prolonged periods of time (mean 25 days). This is the first study to longitudinally evaluate gastric emptying following head injury. The authors suggest that patients with moderate to severe head injury often experience alterations in gastric emptying which may affect their ability to tolerate enteral feedings.