Aeromedical trauma sonography by flight crews with a miniature ultrasound unit.

BACKGROUND: While ultrasound has become an established diagnostic modality in trauma care, no study has evaluated its use in the prehospital setting. OBJECTIVE: To examine the use of the focused abdominal sonography for trauma (FAST) exam in the prehospital setting. METHODS: After a three-hour training session in the FAST exam, the nonphysician flight team of an emergency medical services (EMS) helicopter program attempted a FAST exam on trauma patients to determine the feasibility of such an intervention. RESULTS: The majority (83%) of the 71 patients entered suffered blunt trauma. FAST exams could not be performed in 34 patients (48%) due to insufficient time (67%), inadequate patient access, or combativeness. Technical difficulties (difficult screen visualization due to ambient lighting, battery failure, and machine malfunction) prevented scanning in seven (19%) of the 37 in whom it was attempted. In those in whom scanning was successful, the pelvic view was most commonly obtained followed by the right upper quadrant (RUQ) and left upper quadrant (LUQ). CONCLUSION: Significant advances in training, technology, and/or patient access will be necessary for aeromedical FAST to be feasible.

Thiophosphorylation independently activates each head of smooth muscle myosin in vitro.

To determine whether thiophosphorylation of the 20-kDa myosin light chain activates each head of smooth muscle myosin independently of the head with which it is paired, chicken gizzard smooth muscle myosin was randomly thiophosphorylated, producing a mixture of unphosphorylated and singly and doubly thiophosphorylated myosin. Thiophosphorylation levels were measured by glycerol-urea gels, and the activity of this myosin was determined by actin-activated adenosinetriphosphatase measurements and in an in vitro motility assay, where the velocity of actin filaments moving over a myosin-coated surface is measured. Activity at each thiophosphorylation level was similar to that previously observed for mixtures of unphosphorylated and doubly thiophosphorylated myosin (D. E. Harris, S. S. Work, R. K. Wright, N. R. Alpert, and D. M. Warshaw. J. Muscle Res. Cell Motil. 15: 11-19, 1994). All doubly thiophosphorylated myosin was then formed into filaments and removed from randomly thiophosphorylated myosin by centrifugation. The remaining myosin (mixture of unphosphorylated and singly phosphorylated myosin), which could not polymerize because of their conformation, retained approximately 70% activity compared with mixtures of unphosphorylated and doubly thiophosphorylated myosin. Thus a thiophosphorylated smooth muscle myosin head can produce substantial biochemical and mechanical activity, even when it is paired with an unphosphorylated partner.

D2 dopamine receptor localization on striatonigral neurons.

Two major pharmacological classes of dopamine receptors exist in the central nervous system. These receptors have been designated as D1 or D2 based upon their differing pharmacology and influence on the cyclic AMP second messenger system. Different genes for the D1 and D2 dopamine receptors have been isolated and are found to be expressed in high abundance. Within the neostriatum, however the cellular distribution of the dopamine receptors is equivocal. Dopamine receptors are the targets for drugs used to treat neurological dysfunctions such as Parkinson's disease and schizophrenia, and thus knowledge of their specific cellular location is important for devising future therapeutic manipulations. Using retrograde labeling methods combined with immunofluorescence of various receptor amino acid sequences, this study has examined the postsynaptic distribution of striatal D2 dopamine receptors. We have found that the D2 dopamine receptor can be visualized on a minimum of 60% of the neurons projecting from the neostriatum to the substantia nigra. However, some 65% of all D2 receptor positive cells are represented by other intrinsic neurons of this basal ganglia nucleus.