Is a subset of wrist ganglia the sequela of internal derangements of the wrist joint? MR imaging findings.

PURPOSE: To determine if there is an association between wrist ganglia and internal derangements of the wrist joint by reviewing magnetic resonance (MR) images. MATERIALS AND METHODS: Two observers retrospectively reviewed MR images of the wrist obtained in 625 patients at 1.5 T for the presence of ganglia and associated triangular fibrocartilage complex, scapholunate ligamentous, or lunotriquetral ligamentous tears that were within 3 mm of the ganglion. When available, surgery and/or pathology records were reviewed. RESULTS: There were 122 ganglia and 37 internal derangements. Of the 22 ulnar-sided ganglia, 10 (45%) demonstrated associated triangular fibrocartilage complex tears. Of the 97 radial-sided ganglia, 27 (28%) demonstrated ligamentous tears related to the site of the ganglion. The radial-sided tears involved the radial aspect of the triangular fibrocartilage complex in 12 ganglia; the scapholunate ligament, in isolation, in eight ganglia; and both the triangular fibrocartilage complex and the scapholunate ligament in six ganglia. Only one of the ganglia demonstrated an associated lunotriquetral ligamentous tear. Surgical findings confirmed the ligamentous tears in 25 patients. CONCLUSION: Wrist ganglia are associated, not infrequently, with internal derangements of the wrist.

MR imaging of the type II lunate bone: frequency, extent, and associated findings.

OBJECTIVE: Type II lunate bones have an "extra" facet that articulates with the hamate bone, which frequently leads to arthritis. Because the only prior studies, to our knowledge, on this common and clinically significant variant involved dissection of cadavers, we performed an MR imaging study of the type II lunate. MATERIALS AND METHODS: We retrospectively reviewed MR images obtained at 1.5 T of 186 wrists for frequency of type II lunates, size of the extra facet, amount of hamatolunate apposition, and presence of hamate subchondral edema. Of the 186 wrists, 28 also had correlation with findings on wrist arthroscopy. RESULTS: One hundred seven wrists (57.5%) had type II lunates with an average extra facet size of 4.6 mm (range, 1.2-12.0 mm). Apposition (articulation) of the extra lunate facet with the hamate averaged 77.4% (range, 0-100%). Hamate edema was seen in only nine wrists (4.8%), all of which had type II lunates. Arthroscopic evidence of focal hamate chondromalacia and MR imaging evidence of marrow edema were seen in six of these nine wrists; marrow edema was seen only in wrists with frank cartilage changes on arthroscopy. CONCLUSION: An extra facet (type II lunate) was seen in approximately half of 186 wrists. On MR imaging, type II lunates usually have an innocuous appearance. A large percentage of patients with type II lunates also have chondromalacia, which often is occult on MR imaging. When visible, such chondromalacia is the cause of marrow edema similar to that seen in patients with carpal fractures.

[Nomographs for determination of sedimentation constants of nucleic acids by means of centrifugation in sucrose gradients using the "Sinco" ultracentrifuge]. / Nomogrammy dlia opredeleniia konstant sedimentatsii nukleinovykh kislot tsentrifugirovaniem v gradiente kontsentratsii sakharozy na ul'tratsente kontsentratsii sakharozy na ul'tratsentrifugakh "Spinco".

A set of nomographs for determination of standard sedimentation constant values for DNA and RNA directly from the results of centrifugation without any marker is calculated and plotted for 9 Spinco bucket-rotors, 5 temperatures, and two commonly used sucrose gradients (5--20 and 15--30%).

[Comparison of the isoacceptor makeup of transfer RNA for 2 early stages in the development of loach embryos]. / Sopostavlenie izoaktseptornogo sostava transportnykh RNK dlia dvukh rannikh stadi56I RAZVITIIIA ZARODYSHEI V'IUNA.

The chromatographic profiles of isoacceptor tRNA's for 9 amino acids from the loach embryos at two early developmental stages were compared by the method of chromatography on sepharose column in the decreasing gradient of ammonium sulphate concentration to elucidate the possible role of tRNA in the control of early embryogenesis processes. Certain differences both in the proportions of some isoacceptor peaks and their relative positions on the chromatographic profile were found for 8 aminoacyl tRNA. Methionyl-tRNA was represented by one constant peak.