Kienb?ck's disease

Kienb?ck's disease is an isolated disorder of the lunate resulting from vascular compromise to the bone. The symptoms include wrist pain, limited range of motion, and decreased grip strength. The diagnosis is made from characteristic changes seen in the lunate on radiograms of the wrist. The severity of the disease can be categorized by staging the degree of involvement. This is helpful in guiding the practitioner through the maze of treatment options. Initial treatment of Kienb?ck's disease is conservative and includes immobilization, analgesics, and/or anti-inflammatory medication. If symptoms are not relieved, then based on the degree of involvement, several surgical options exist that will provide a successful result. These include autogenous tendon replacement arthroplasty, revascularization, radial shortening, ulnar lengthening, limited intercarpal arthrodesis, and silicone replacement arthroplasty. Salvage procedures for Kienb?ck's disease include wrist denervation, wrist arthrodesis, and proximal-row carpectomy. Currently, we prefer immobilization for treatment of stage I Kienb?ck's disease. For stage II, a revascularization procedure may be attempted or ulnar lengthening/radial shortening done, particularly if there is significant negative ulnar variance. In stage III, replacement arthroplasty and/or limited intercarpal arthrodesis is our treatment of choice, and for stage IV, one of the salvage procedures is indicated.     

Entry-Level Degrees for Midwifery Practice

The Governing Board of the ACNM Division of Accreditation (DOA) has been charged by the ACNM Board of Directors to consider requiring an entry-level degree for nurse-midwifery practice. This decision has far-reaching implications and must be considered with utmost care. The decision will not be based on the issue of clinical competence but rather, the political statement to be made through the imposition of a degree requirement. The author urges the DOA's Governing Board to consider the implications of its action on a variety of audiences, including potential students, potential consumers, other health professionals, current and future employers, our international colleagues, health insurers and managed care organizations, and policymakers and lawmakers.     

Stability of Th1 and Th2 populations

Using an in vitro model for the development of IFN-y-producIng(Th1) and IL-4-produclng (Th1) cells from CD4 T lymphocytesexpressing a transgenlc TCR, we show that IL-12 and IL-4 arethe most potent stimuli for the differentiation of naive T cellsto effector populations. When combinations of cytokines arepresent during T cell priming, the effect of IL-4 Is dominant.Furthermore, differentiated Th1 cells can be converted intoIL-4 producers by exposure to IL-4, but the Th2 phenotype Isnot reversible. The stability of Th2 populations may limit theability to regulate Th2-domlnant responses In pathologic situations.     

Systemic or intrahippocampal cannabinoid administration impairs spatial memory in rats

The purpose of the present study was to investigate the disruptive effects of cannabinoids on working memory as assessed in the eight-arm radial-maze. Systemic administration of ⁹-THC, WIN-55,212-2, and CP-55,940 increased the number of errors committed in the radial-maze. CP-55,940 was the most potent cannabinoid in impairing memory (ED₅₀=0.13 mg/kg). ⁹-THC and WIN-55,212-2 disrupted mazechoice accuracy at equipotent doses (ED₅₀ values =2.1 and 2.2 mg/kg, respectively). In addition, systemic administration of each of these agents retarded completion time. Whereas the doses of ⁹-THC and CP-55,940 required to retard maze performance were higher than those needed to increase error numbers, WIN-55,212-2 was equipotent in both of these measures. On the other hand, neither anandamide, the putative endogenous cannabinoid ligand, nor cannabidiol, an inactive naturally occurring cannabinoid, had any apparent effects on memory. A second aim of this study was to elucidate the neuroanatomical substrates mediating the disruptive effects of cannabinoids on memory. Intrahippocampal injections of CP-55,940 impaired maze performance in a dose-dependent manner (ED₅₀=8 µg/rat), but did not retard the amount of time required to complete the maze. The effects of intrahippocampal CP-55,940 were apparently specific to cognition because no other cannabinoid pharmacological effects (e.g., antinociception, hypothermia, and catalepsy) were detected. This dissociation between choice accuracy in the radial-maze and other cannabinoid pharmacological effects suggests that the working memory deficits produced by cannabinoids may be mediated by cannabinoid receptors in the hippocampus.     

The vasa vasorum and angioplasty

Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.     

Acute injuries of the distal radioulnar joint

Distal radioulnar joint injuries can occur in isolation or in association with distal radius fractures, Galeazzi fractures, Essex-Lopresti injuries, and both-bone forearm fractures. The authors have classified DRUJ/TFCC injuries into stable, partially unstable (subluxation), and unstable (dislocation) patterns based on the injured structures and clinical findings. Clinical findings and plain radiographs are usually sufficient to diagnose the lesion, but axial CT scans are pathognomonic. Diagnostic arthroscopy is the next test of choice to visualize stable and partially unstable lesions. Stable injuries of the DRUJ/TFCC unresponsive to conservative measures require arthroscopic debridement of the TFCC tear, along with ulnar shortening if there is ulnar-positive variance. Partially unstable injuries, on the other hand, are treated with direct arthroscopic or open repair of the TFCC tear, once again, along with ulnar shortening if ulnar-positive variance is present. Unstable injuries include simple and complex DRUJ dislocations. A simple DRUJ dislocation is easily reducible but may be stable or unstable. In complex dislocation, reduction is not possible because there is soft tissue interposition or a significant tear. After the associated injury is dealt with, treatment for complex injuries requires exploration of the DRUJ, extraction of the interposed tissue, repair of the soft tissues, and open reduction and internal fixation of the ulnar styloid fracture (if present and displaced). The early recognition and appropriate treatment of an acute DRUJ injury are critical to avoid progression to a chronic DRUJ disorder, the treatment of which is much more difficult and much less satisfying.