The ring butterfly fragment in diaphyseal fractures: its importance in flexible intramedullary nailing.

Ring butterfly fragment was described after it was noted to pose problems during insertion of flexible intramedullary nails. This fragment contains the entire circumference of the medullary canal or a substantial part of it. Once recognized preoperatively the fragment is reduced, providing a stable fracture configuration for fixation with flexible intramedullary nails. If the fragment is left displaced, it may lead to nonunion of the fracture; particularly after flexible intramedullary nailing of the tibia.

Single-incision technique for internal fixation of distal tibia and fibula fractures.

Open reduction and internal fixation of distal tibia and fibula fractures generally involves two separate incisions: an anteromedial incision to approach the tibia and a lateral incision to approach the fibula. Exposing the distal tibia from the medial side is associated with the risk of wound dehiscence, infection, and discomfort to the patient since the hardware is directly beneath the skin. By using a single incision from the anterolateral side, the fibular fracture can be fixed and the lateral aspect of the distal tibia can be safely approached for internal fixation, thus eliminating the need for two separate incisions.

Tips of the trade #41. Modified coaptation splint for humeral shaft fractures.

A technique for applying a modified coaptation splint for humeral shaft fractures is presented. Using this method, the splint extends from the base of the neck, passes over the shoulder and along the front and back of the arm, and returns toward the axillary fold. To prevent slippage, the proximal end of the splint is secured to the chest with a strap.

Recognition of leguminous hosts by a promiscuous Rhizobium strain.

The lima bean (Phaseolus lunatus L.) and the pole bean (Phaseolus vulgaris L.) are nodulated by rhizobia of two different cross-inoculation groups. Rhizobium sp. 127E15, a cowpea-type Rhizobium, can induce effective nodules on the lima bean and partially effective nodules on the pole bean. Rhizobium phaseoli 127K14 can induce effective nodules on the pole bean but does not reciprocally nodulate the lima bean. Root hairs of the lima bean when inoculated with Rhizobium sp. 127E15 showed tip curling and swelling and infection thread formation as observed by light microscopy and scanning electron microscopy. When lima bean root hairs were inoculated with R. phaseoli 127K14, no host-specific responses were observed. Pole bean root hairs that had been inoculated with R. phaseoli 127K14 or Rhizobium sp. 127E15 also showed tip curling and swelling and infection thread formation. Colonization of lima bean root hairs by Rhizobium sp. 127E15 and pole bean root hairs by R. phaseoli 127K14 or Rhizobium sp. 127E15 appeared to involve the elaboration of microfibrils. This study showed that when Rhizobium sp. 127E15 nodulates a host of a different cross-inoculation group, it elicits the same specific host responses as it does from a host of the same cross-inoculation group.

Cloning of Protocatechuate 3,4-Dioxygenase Genes from Bradyrhizobium japonicum USDA110.

A heterologous gene probe encoding the alpha and beta subunits of the Pseudomonas cepacia protocatechuate 3,4-dioxygenase (PCD) was used to detect its homolog in the genome of Bradyrhizobium japonicum USDA110. Three cosmid clones carrying a 2.2-kb BamHI insert showed high levels of PCD activity. SacI digestion of one of the genomic clones, pBjG17, produced a 2.5-kb insert DNA that complemented a PCD mutant of P. cepacia.

Fractionation and characterization of two morphologically distinct types of cells in Rhizobium japonicum broth culture.

Differential centrifugation of stationary phase broth culture of Rhizobium japonicum yielded two distinct morphological types of bacterial cells, rods, and small coccoid forms with capsulated and non-capsulated cells in each group. The rods usually had polar capsules which resulted in "star" formation. The coccoid bacteria were either free with thick capsular material surrounding the cells or held together in a common capsular sheath forming clusters and chains. 125I soybean. lectin bound to the two types of cells. The binding sites were localized in the capsular material as revealed by colloidal gold- and ferritin-labelled lectin. Both fractions were capable of nodule formation in the soybean.

Changes in the outer cell wall of Rhizobium during development of root nodule symbiosis in soybean.

Treatment of soybean root nodule tissue with a nonionic detergent. Nonidet P-40, after aldehyde fixation, results in a selective solubilization of membranes. The cell wall membrane of bacteroids and of free-living Rhizobium is resistant to this treatment. Fragments of "extra" membrane present inside the membrane envelope enclosing the bacteroids are also resistant to the detergent and are morphologically similar to the outer membrane of the cell wall of Rhizobium grown in broth culture. These observations, along with electrophoretic profiles of detergent resistant membranes from nodules, free-living Rhizobium, and isolated nodule bacteroids, suggest that the Rhizobium cell wall membrane undergoes significant changes during establishment of the root nodule symbiosis.

Comparison of lateral pillar classification and Catterall classification of Legg-Calvé-Perthes' disease.

To compare the predictive value of the Herring lateral pillar and the Catterall classifications of Legg-Calvé-Perthes' disease, 71 hips with radiographic follow-up to maturity were reviewed. The Herring classification was a significantly better predictor of Stulberg outcome than the Catterall classification. Three independent observers classified early fragmentation stage films by both Herring and Catterall classifications. The interobserver reliability of the Herring classification was significantly better than the reliability of the Catterall measure.

Nodulation of Pole Bean (Phaseolus vulgaris L.) by Rhizobium Species of Two Cross-Inoculation Groups.

Physiology and morphology of pole bean (Phaseolus vulgaris L. cv Kentucky Wonder) root nodules induced by two Rhizobium species of different cross-inoculation groups have been compared. Root nodules induced by Rhizobium sp. 127E15, which is a strain of the cowpea group Rhizobium, were pinkish, had irregular shapes, and were only partially effective. Their peak acetylene reduction activity was 4.36 mumol of C(2)H(4) formed per g of fresh nodules per h at 30 days after inoculation. The effective nodules induced by Rhizobium phaseoli 127K14, which is a strain of the bean group Rhizobium, were dark red, spherical, and showed peak acetylene reduction activity of 15.95 mumol of C(2)H(4) formed per g of fresh nodules per h at 15 days after inoculation. The partial effectiveness of 127E15-induced nodules was associated with fewer infected cells, a delay in the increase of bacteroid population within the host cells, abundance of cytoplasmic vesicles in the host cells, more bacteroids within a membrane envelope (peribacteroid membrane), and the inability of bacteroids to completely fill up the host cytoplasmic space. The 127K14-induced nodules were fully mature, with host cells filled with bacteroids by 12 days after inoculation. In contrast, the 127E15-induced nodules did not reach a similar developmental stage even 30 days after inoculation.

Ultrastructure of Rhizobium japonicum in relation to its attachment to root hairs.

In Rhizobium japonicum strain Nitragin 61A76, morphologically distinct types of bacteria were found to occur in yeast extract-mannitol broth cultures, at both mid-log and stationary phases. Of these only the capsular form, characterized by a smooth cell envelope, storage granules (glycogen and poly-beta-hydroxybutyric acid), and an amorphous extracellular capsule, bound soybean lectin. The binding site was localized in the capsular material. Less than 1% of the bacterial population differentiated into these capsular forms, which were also able to attach to the soybean root hair surface.

Molecular cloning and expression of Rhizobium fredii USDA 193 nodulation genes: extension of host range for nodulation.

DNA hybridization with the cloned nodulation region of Rhizobium meliloti as a probe revealed DNA homology with four HindIII fragments, 12.5, 6.8, 5.2, and 0.3 kilobases (kb) in size, of the symbiotic plasmid pRjaUSDA193. Both hybridization and complementation studies suggest that the common nodulation genes nodABC and nodD of R. fredii USDA 193 are present on the 5.2-kb HindIII and 2.8-kb EcoRI fragments, respectively, of the Sym plasmid. Both fragments together could confer nodulation ability on soybeans when present in Sym plasmid-cured (Sym-) and wild-type (Sym+) Rhizobium strains or in a Ti plasmid-cured Agrobacterium tumefaciens strain. Furthermore, the 2.8-kb EcoRI fragment alone was able to form nodulelike structures on Glycine max L. cv. "Peking" (soybean). Microscopic examination of these nodules revealed bacterial invasion of the cells, probably via root hair penetration. Bacterial strains harboring plasmids carrying the 5.2- and 2.8-kb nod fragments elicited root-hair-curling responses on infection. These data suggest that the genes responsible for host range determination and some of the early events of nodulation may be coded for by the 5.2-kb HindIII and 2.8-kb EcoRI fragments.