Management of proximal interphalangeal joint injuries

Injuries to the proximal interphalangeal joint are common but frequently missed. They are often overtreated by prolonged immobilization, resulting in stiffness, which may be permanent. The purpose of the present article is to briefly review the relevant anatomy and biomechanics, present an approach to physical examination and diagnosis, and propose a practical clinical classification. The treatment of the most severe injury – the intra-articular fracture dislocation – is controversial. The various treatment options are discussed, based on personal experience and a review of the literature. A list of relevant references is presented.     

Breast cancer metastasis and lymph node lymphocyte-macrophage interaction

A lymphocyte-macrophage interaction, known as the lymphocyte clustering phenomenon, was studied in axillary lymph node preparations from 27 breast cancer patients. The study was carried out in primary tissue cultures of lymph nodes and the lymphocyte-macrophage interactions were quantitated with respect to cancer positive and cancer negative axilla. The results indicate that there is a significantly higher (p< 0.025) lymphocyte-macrophage interaction in negative node preparations from negative axilla of infiltrating ductal carcinoma patients. This new approach to lymph node lymphocyte evaluation may provide assistance in determining the extent of the disease process.     

Management of proximal interphalangeal joint injuries

Injuries about the PIP joint of the finger are commonly encountered by primary care physicians and are associated with significant morbidity, including pain, stiffness, instability, premature degenerative arthritis, and residual deformities. An accurate understanding of the regional anatomy and appreciation of the mechanism of injury allows for classification so that a treatment protocol can be formulated for each injury pattern. Emphasis on careful consideration of the implications of open reduction, rational splinting, and early, active, protected motion provides for the most favorable outcome.     

Three-dimensional tibiofemoral articular contact kinematics of a cruciate-retaining total knee arthroplasty

BACKGROUND: Accurate knowledge of the location of tibiofemoral articular contact following total knee arthroplasty is important in order to understand polyethylene wear and the mechanisms of component failure. The present study was performed to determine the three-dimensional tibiofemoral articular contact patterns of a posterior cruciate ligament-retaining total knee replacement during in vivo weight-bearing flexion. METHODS: Nine osteoarthritic patients who were managed with a single design of a posterior cruciate ligament-retaining total knee implant were investigated with the use of an innovative dual orthogonal fluoroscopic imaging system. The position of the components during in vivo weight-bearing flexion was measured from full extension to maximum flexion in 15 degrees intervals. Tibiofemoral articular contact was determined by the overlap of the tibiofemoral articular surfaces. The centroid of the surface intersection was used to report the point of contact location. The average tibiofemoral contact points on both the medial and lateral tibial component surfaces were reported as a function of flexion. RESULTS: The average maximum weight-bearing flexion angle was 113.3 degrees +/- 13.1 degrees (range, 96 degrees to 138 degrees ). In the anteroposterior direction, the contact location was relatively constant in the medial compartment and moved posteriorly by 5.6 mm in the lateral compartment as the knee flexed from full extension to 90 degrees of flexion. The range of the contact location in the mediolateral direction was 3.7 mm in the medial compartment and 4.8 mm in the lateral compartment. For both compartments, posterior translation of the contact point was significant from 90 degrees to maximum flexion, but the contact point at maximum flexion was not observed to reach the posterior edge of the polyethylene tibial insert articular surface. CONCLUSIONS: While the minimum anteroposterior translation of the contact point on the medial side might be interpreted as a medial pivot rotation during knee flexion, the contact point did move in the mediolateral direction with flexion. Beyond 90 degrees , both medial and lateral contact points were shown to move posteriorly but stopped before reaching the posterior edge of the polyethylene tibial insert articular surface. It seemed that the current component design did not allow the femoral condyle to roll off the polyethylene edge at high degrees of flexion because of the geometry at the posterior lip.     

Matched unrelated umbilical cord blood transplantation for a patient with chemotherapy resistant Wilms tumor

We report a patient with chemotherapy refractory Wilms tumor who underwent an unrelated donor cord blood transplant for chemotherapy refractory disease. The preparative regimen consisted of busulfan, melphalan, and anti‐thymocyte globulin, and was well tolerated. This patient did not experience significant toxicity related to the chemotherapy regimen and did not develop any graft versus host disease from his HLA (A, B, DR) 6/6 matched cord blood transplant. Follow‐up CT scans 2 years post‐transplant have shown no evidence of disease progression, with only a few pulmonary nodules remaining, which are unchanged in size from his pre‐transplant CT scan. It is possible that high‐dose chemotherapy and stem cell transplantation can be curative in patients with tumors that are non‐responsive to conventional chemotherapy. Pediatr Blood Cancer. 2010;55:763–765. © 2010 Wiley‐Liss, Inc.     

Glucocorticoids increase the Na+-H+ exchange and decrease the Na+ gradient-dependent phosphate-uptake systems in renal brush border membrane vesicles.

The glucocorticoid dexamethasone, but not the mineralocorticoid aldosterone, increased amiloride-sensitive Na+-H+ exchange activity in rat proximal tubule brush border vesicles. Na+ uptake, independent of amiloride, was not affected. The glucocorticoid decreased the Na+ gradient-dependent phosphate uptake. Uptake in the absence of a Na+ gradient was not inhibited. Dexamethasone did not affect the Na+ gradient-dependent D-glucose uptake. These findings are consistent with the effects of glucocorticoids in stimulating acid secretion and causing phosphaturia in man and animals and may identify the locus of action and suggest the mechanisms by which the hormones act.     

Identification of novel cellular targets for therapeutic intervention against Ebola virus infection by siRNA screening

While much progress has been made in developing drugs against a few prominent viruses such as HIV, few examples exist for emerging infectious agents. In some cases broad spectrum anti-viral drugs, such as ribavirin, are effective, but for some groups of viruses, these show little efficacy in animal models. Traditional methods focus on screening small molecule libraries to identify drugs that target virus factors, with the intention that side-effects to the host can be minimized. However, this greatly limits potential drug targets and virus genes can rapidly mutate to avoid drug action. Recent advances in siRNA gene targeting technologies have provided a powerful tool to specifically target and suppress the expression of cell genes. Since viruses are completely dependent upon host cell proteins for propagation, siRNA screening promises to reveal novel cell proteins and signaling pathways that may be viable targets for drug therapy regimens. Here we used an siRNA screening approach to identify gene products that play critical roles in Ebola virus infection. By gene cluster analysis, proteins in phosphatidylinositol-3-kinase and calcium/calmodulin kinase related networks were identified as important for Zaire Ebola virus infection and prioritized for further evaluation. Key roles of each were confirmed by testing available drugs specific for members of each pathway. Interestingly, both sets of proteins are also important in cancer and subject to intense investigation. Thus development of new drugs against these cancer targets may also prove useful in combating Ebola virus.