[Quantitative classification of pivot-shift maneuver]. / Clasificación cuantitativa de la maniobra de pivot-shift.

INTRODUCTION: The diagnosis of ACL injury is established with the physical examination that includes the Lachman maneuver and the pivot-shift test since it has the highest positive predictive value. Imaging tests such as MRI are still used for confirmation of the same; so the quantification of clinical maneuvers is sought. MATERIAL AND METHODS: Prospective clinical study in which the maneuvers of pivot-shift and Lachman are quantified for later classification. RESULTS: Of 36 patients, 64% found a range between 0 and 3 mm when subtracting the value of the affected knee from the value of the healthy knee. It was found that 28% of the patients recorded values of KT-1000 ranging between 4 and 6 mm of displacement. In 8% of the total patients, values of KT-1000 were found that exceeded 7 mm of displacement. The data obtained are normalized and classified into 3 degrees of injury: grade 1 with partial injury; grade 2 with complete anteromedial and partial injury in posterolateral bundle; grade 3 with complete injury of both bundles. CONCLUSION: A classification is proposed for the degrees of ACL injury with future application to a more personalized reconstruction.

INTRODUCCIÓN: El diagnóstico de lesión del ligamento cruzado anterior se establece con la exploración física que incluya la maniobra de Lachman y la prueba de pivot-shift, ya que cuenta con el mayor valor predictivo positivo. Aún se recurre a pruebas de gabinete como la RMN para la confirmación del mismo; por lo que se busca la cuantificación de maniobras clínicas. MATERIAL Y MÉTODOS: Estudio clínico prospectivo en el que se cuantifican las maniobras de pivot-Shift y Lachman para su posterior clasificación. RESULTADOS: De 36 pacientes, 64% se encontró un rango entre 0 y 3 mm al restar al valor de la rodilla sana el valor de la rodilla afectada. Se encontró que 28% de los pacientes, registraron valores de KT-1000, que oscilan entre los 4 y 6 mm de desplazamiento. En 8% del total de los pacientes se encontraron valores de KT-1000 que superaron los 7 mm de desplazamiento. Se normalizan los datos obtenidos y se clasifican en 3 grados de lesión: grado 1 con lesión parcial; grado 2 con lesión completa de haz anteromedial y parcial en haz posterolateral; grado 3 con lesión completa de ambos haces. CONCLUSIONES: Se propone una clasificación para los grados de lesión del LCA con futura aplicación a una reconstrucción más personalizada.

Reduction of calcineurin activity in brain by antisense oligonucleotides leads to persistent phosphorylation of tau protein at Thr181 and Thr231.

Phosphorylation of tau protein promotes stability of the axonal cytoskeleton; aberrant tau phosphorylation is implicated in the biogenesis of paired helical filaments (PHF) seen in Alzheimer's disease. Protein kinases and phosphatases that modulate tau phosphorylation have been identified using in vitro techniques; however, the role of these enzymes in vivo has not been determined. We used intraventricular infusions of antisense oligodeoxynucleotides (ODNs) directed against the major brain isoforms of the Ca2+/calmodulin-dependent phosphatase calcineurin to determine how reduced activity of this enzyme would affect tau dephosphorylation. Five-day infusions of antisense ODNs (5 and 10 nmol/day) in rats decreased immunoreactive levels and activity of calcineurin throughout the brain; sense ODNs, scrambled ODNs, and infusion vehicle alone had no effect. When neocortical slices were prepared from antisense ODN-treated rats and incubated for 1 to 2 h in vitro, tau protein remained phosphorylated as determined by using the phosphorylation-sensitive monoclonal antibodies AT-180 (Thr231) and AT-270 (Thr181). In contrast, AT-180 and AT-270 sites were completely dephosphorylated during incubation of neocortical slices from vehicle-infused controls and sense ODN-treated rats. Neocortical slices from antisense-treated rats were incubated with the phosphatase inhibitors okadaic acid (100 nM; 10 microM) and FK-520 (5 microM); these preparations showed enhanced tau phosphorylation, consistent with a significant loss of calcineurin activity. Thus, we conclude that phosphorylation of at least two sites on tau protein, namely, Thr181 and Thr231, is regulated by calcineurin.

Quantification of G protein mRNA using reverse transcription and competitive PCR with a colorimetric microplate assay.

This paper reports an assay for the quantification of levels of specific mRNA for the alpha subunits of the inhibitory G proteins G alpha i-1, G alpha i-2, and G alpha i-3. The assay employs reverse transcription and competitive polymerase chain reaction (PCR) coupled to enzyme-linked oligonucleotide sorbent assay for differential detection and quantification of PCR products. The assay was conducted with conventional thermal block PCR cyclers as well as rapid air microcapillary cyclers. The detection stage consists of three steps using synthetic oligonucleotides, commercially available reagents and a conventional 96-well plate absorbance reader at settings of 450 and 630 nm. The assay is: (1) rapid, requiring about 3 h for quantification of PCR products; (2) safe, being non-radiometric; (3) relatively simple; (4) highly sensitive, being capable of detecting less than 10 initial copies of target cDNA; (5) precise, resolving two-fold differences in initial copy numbers of specific sequences as low as 10(-20) mol; (6) linear over a 3 log range, with two-fold differences in the quantity of cDNA producing consistent reductions in quantity of specific cDNA detected; and (7) reproducible, intra-assay and inter-assay coefficients of variation being 11.9 and 14.7%, respectively.

On the moving-obstacle path-planning algorithm of Shih, Lee, and Gruver.

We analyze a motion planning algorithm proposed by Shih, Lee, and Gruver (1990). In particular, we discuss the case of motion planning among moving obstacles, for which an algorithm is presented by Shih, Lee, and Gruver (1990). The algorithm is claimed to always yield a collision-free path when one exists. We provide a specific counter-example to this claim, examine the possibility of repairing the algorithm, and discuss the computational complexity of a corrected algorithm.

A counterexample to the Alexopoulos-Griffin path planning algorithm.

The planar stationary-obstacle path-planning problem for polygonal obstacles has been correctly and completely solved by T. Lozano-Perez and M. Wesley (1979), i.e., a global, optimal algorithm was provided which requires O(mu(2)logmu) computation time, where mu is the number of obstacle-faces in the scene. That algorithm is known as the VGRAPH algorithm. Two variants of VGRAPH have been developed to solve the same problem in O(mu(2)) computation time. Our paper discusses a recent algorithm proposed by C. Alexopoulos and P.M. Griffin (1992), called V*GRAPH, which also claims to provide an optimal solution. We demonstrate by counter-example that V*GRAPH is neither global nor optimal.

Interscalene block anesthesia for shoulder surgery.

One hundred patients had major shoulder surgery with interscalene brachial and cervical plexus block anesthesia. Successful anesthesia was obtained by using this method in 82 patients. Failure was the result of incomplete anesthesia in 16 patients or the presence of a complication. Complications from high blood levels of anesthetic included loss of consciousness and respiratory depression in three patients and seizure in one. The block lasted a mean of eight hours, decreasing the need for postoperative analgesic medications. No postoperative medical complication developed. Ninety-one percent of the patients with successful blocks were satisfied with the procedure.