CXCR2 expression during melanoma tumorigenesis controls transcriptional programs that facilitate tumor growth.

Background: Though the CXCR2 chemokine receptor is known to play a key role in cancer growth and response to therapy, a direct link between expression of CXCR2 in tumor progenitor cells during induction of tumorigenesis has not been established. Methods: To characterize the role of CXCR2 during melanoma tumorigenesis, we generated tamoxifen-inducible tyrosinase-promoter driven Braf V600E /Pten -/- /Cxcr2 -/- and NRas Q61R /INK4a -/- /Cxcr2 -/- melanoma models. In addition, the effects of a CXCR1/CXCR2 antagonist, SX-682, on melanoma tumorigenesis were evaluated in Braf V600E /Pten -/- and NRas Q61R /INK4a -/- mice and in melanoma cell lines. Potential mechanisms by which Cxcr2 affects melanoma tumorigenesis in these murine models were explored using RNAseq, mMCP-counter, ChIPseq, and qRT-PCR; flow cytometry, and reverse phosphoprotein analysis (RPPA). Results: Genetic loss of Cxcr2 or pharmacological inhibition of CXCR1/CXCR2 during melanoma tumor induction resulted in key changes in gene expression that reduced tumor incidence/growth and increased anti-tumor immunity. Interestingly, after Cxcr2 ablation, Tfcp2l1 , a key tumor suppressive transcription factor, was the only gene significantly induced with a log 2 fold-change greater than 2 in these three different melanoma models. Conclusions: Here, we provide novel mechanistic insight revealing how loss of Cxcr2 expression/activity in melanoma tumor progenitor cells results in reduced tumor burden and creation of an anti-tumor immune microenvironment. This mechanism entails an increase in expression of the tumor suppressive transcription factor, Tfcp2l1, along with alteration in the expression of genes involved in growth regulation, tumor suppression, stemness, differentiation, and immune modulation. These gene expression changes are coincident with reduction in the activation of key growth regulatory pathways, including AKT and mTOR.

Dissections of regional lymph nodes for treatment of skin cancer: predicting annual caseloads that will optimise outcomes.

INTRODUCTION: Dissection of regional lymph nodes (RLNs) can lead to significant morbidity and a high prevalence of complications. Published guidance states that these procedures should be carried out by surgeons who are members of a specialist skin multidisciplinary team who carry out a combined minimum of 15 axillary/groin dissections per year. However, there is little evidence to guide this minimum figure of procedures. We report on the burden of service provision and prevalence of complications across the South West of England and Wales. METHODS: A 12-month review of dissections of RLNs for skin cancer was undertaken covering five Plastic Surgery Units with a collective catchment of 8.4 million people. Detailed data were collected on patient demographics, pathology, timing of surgery, and prevalence of complications. RESULTS: A total of 163 dissections were carried out. Forty-three per cent of patients experienced one or more complication. In that 12-month period, an average of 8 axillary/groin dissections was carried out per surgeon. A funnel plot demonstrated that the prevalence of complications for individual surgeons was within the limit of the plot but, in many cases, this was based only on a relatively small number of procedures per consultant. If surgeons carried out 10 procedures per year, the upper and lower limits on the plot were 73% and 11%, respectively. CONCLUSIONS: Funnel plots can provide a useful guide as to whether the prevalence of complications for procedures for individual surgeons lies within acceptable limits. Based on these results, 10 procedures per consultant per year should be sufficient to enable meaningful assessment of the prevalence of complications.

Osteoblast differentiation onto different biometals with an endoprosthetic surface topography in vitro.

In this in vitro study, we compared the cytocompatibility and osteoblast promoting potency on human bone marrow cell culture with three different alloys (surgical steel, CoCr, Ti6Al4V) and three different surface structures (polished, sandblasted, porous coated). These biometals were specifically chosen because of their current applications in clinical orthopedic practices. Human mononuclear bone marrow cells were cultivated onto the surface of the different biomaterials and stimulated by dexamethasone, L-ascorbic-acid-2-phoshpate and beta-glycerolphosphate over a 3-week period. Immunofluorescent stainings against several antigens (ALP, RANKL, osteopontin, collagen I), mRNA-expression of collagen (Col) I/II, BSP, osteopontin, osteocalcin, TRAP, light and scanning electron microscopy evaluation were used to evaluate cellular growth and osteoblast differentiation. For surface roughness and energy analysis of the specimen, roughness profile (Ra, Rz) and contact angle (CA) measurements were performed. We found differences between the different biometals and surface structures. Steel showed potential cytotoxic effects whereas CoCr and more Ti6Al4V showed an excellent cytocompatibility. There were no qualitative differences in mRNA expression between each of the tested biomaterials. In terms of antigen expression, a sandblasted Ti6Al4V surface showed enhanced osteoblastic differentiation. A porous-coated surface improved the osteoconductivity of CoCr when compared to a polished surface. In contrast to controls all cells cultivated with biometals induced a RANKL expression. Cells increased the implant roughness with the exception of sandblasted Ti6Al4V. Our data show that surface topography and physicochemical properties of biometals influence osteoblast differentiation in vitro.

Management of burns in the wilderness.

For the practitioner working in the wilderness environment, burns represent a significant challenge. There may be a requirement for non-specialists to provide care with fewer resources than would be available in a specialist unit in the UK. In the wilderness setting, delay prior to reaching specialist care is likely to be an ever present factor. Secondary complications of the burn wound, such as respiratory problems or sepsis may therefore supervene. The paper examines certain aspects of treatment relevant to the wilderness environment, including airway injury, fluid resuscitation and local treatment of the burn wound. Escharotomy and aspects of electrical and chemical injury are also considered.

A phase I study of AMD473 and docetaxel given once every 3 weeks in patients with advanced refractory cancer: a National Cancer Institute of Canada-Clinical Trials Group trial, IND 131.

BACKGROUND: AMD473 (previously ZD0473) is a new-generation platinum compound with activity against a wide range of human tumour cell lines and xenografts, including carboplatin- and cisplatin-resistant lines. To assess its potential combined with a taxane, a phase I study of AMD473 and docetaxel in advanced cancer was initiated by the National Cancer Institute of Canada-Clinical Trials Group. PATIENTS AND METHODS: Patients with advanced cancer, measurable disease, performance status Eastern Cooperative Oncology Group 0-2, no major organ dysfunction, and one or no previous taxane regimen received escalating doses of AMD473 and docetaxel every 3 weeks, with a starting dose of AMD473 80 mg/m(2) and docetaxel 60 mg/m(2). RESULTS: Thirty-three patients enrolled on four dose levels were evaluable for toxicity and 25 patients were evaluable for response. The maximum tolerated dose was dose level 4 (AMD473 120 mg/m(2) and docetaxel 75 mg/m(2)), with grade 4 neutropenia in both minimally and heavily pretreated patients causing dose-limiting toxicity. As well at dose level 4, one patient had grade 3 vomiting despite premedication. Dose level three was expanded for both groups of patients and was defined as the recommended phase II dose at AMD473 100 mg/m(2) and docetaxel 75 mg/m(2). Non-hematologic toxicities included fatigue, diarrhoea and other mild toxicities. There was one partial response in a patient with prostate cancer and stable disease in 15 patients. No apparent pharmacokinetic interaction was noted. CONCLUSION: AMD473 and docetaxel can be combined with a recommended phase II dose level of 100 mg/m(2) and 75 mg/m(2), respectively, given intravenously every 3 weeks. The combination has activity and should be explored in responsive tumour types.

The influence of surface roughness on stem-cement gaps.

We have compared the interface morphology at the stem-cement interface of standard Charnley stems with a satin finish (Ra = 0.75 microm) with identical stems which had been grit-blasted over their proximal third (Ra = 5.3 microm) to promote a proximal bond. The stems were cemented into cadaver femora using conventional contemporary cementing techniques. After transverse sectioning, we determined the percentage of the perimeter of the stem which had a gap at the interface. There were substantial gaps (mean 31.4 +/- 17.1%) at the stem-cement interface in the grit-blasted region. This fraction was significantly (paired t-test, p = 0.0054) higher than that found around the contralateral satin-finished stems (mean 7.7 +/- 11.7%). Although studies of isolated metal-cement interfaces have shown that the bond strength can increase with surface roughness it cannot be assumed that this effect will be observed under clinical conditions.

Surgical repair of intercostal pulmonary hernia secondary to cough induced rib fracture.

Intercostal pulmonary hernia, a protrusion of lung parenchyma with overlying pleural membranes through an abnormal defect in the thoracic cage, is an uncommon phenomenon. Rib fractures caused by coughing similarly represent an infrequently occurring clinical presentation. Pulmonary herniation through an intercostal defect caused by cough fractures has been described twice in the literature to our knowledge. We present a case of pulmonary herniation secondary to cough fracture in a chronic bronchitic, successfully treated by thoracotomy with application of the basic principles of hernia repair, and a discussion of the mechanisms of injury.

Extended survival in advanced and refractory multiple myeloma after single-agent thalidomide: identification of prognostic factors in a phase 2 study of 169 patients.

This report of a phase 2 trial of thalidomide (THAL) (200 mg/d; 200 mg increment every 2 weeks to 800 mg) for 169 patients with advanced myeloma (MM) (abnormal cytogenetics (CG), 67%; prior autotransplant, 76%) extends earlier results in 84 patients. A 25% myeloma protein reduction was obtained in 37% of patients (50% reduction in 30% of patients; near-complete or complete remission in 14%) and was more frequent with low plasma cell labeling index (PCLI) (below 0.5%) and normal CG. Two-year event-free and overall survival rates were 20% +/- 6% and 48% +/- 6%, respectively, and these were superior with normal CG, PCLI of less than 0.5%, and beta(2)-microglobulin of 3 mg/L. Response rates were higher and survival was longer especially in high-risk patients given more than 42 g THAL in 3 months (median cumulative dose) (landmark analysis); this supports a THAL dose-response effect in advanced MM.

Maximizing ultra high molecular weight polyethylene performance in total knee replacement.

The etiology of polyethylene wear following TKR is multifactorial. Factors such as surgical technique, patient selection, and choice of implant design directly impact the polyethylene wear rate. Surgical technique is directly associated with polyethylene wear; particularly the thickness of the polyethylene insert, the postoperative mechanical axis of the limb, and the alignment of the tibial component in the coronal plane. Patient selection is an important determinant of polyethylene wear, as patient body weight and activity level have been shown to correlate with wear rate. Prosthetic design plays a role in polyethylene wear as femoral-tibial contact areas, peak contact forces, and surface topography of the polyethylene are important considerations. The method by which the polyethylene is manufactured and the method of sterilization are also important determinants of polyethylene wear. Wear of polyethylene is one source of particulate debris following TKR. Phagocytosis of the particulate debris by macrophage occurs at the prosthesis-bone interface. The macrophage produces inflammatory mediators in response to the particulate debris. Inflammatory mediators act at the failed interface to effect bone resorption and produce osteolysis. In summary, the surgeon can play a major role in maximizing polyethylene performance in TKR by understanding the multiple factors that contribute to polyethylene wear and taking steps to lessen their effect.

Mixed-mode failure response of the cement-bone interface.

Mechanical failure of the cement-bone interface can contribute to clinical loosening of cemented total hip replacements. The conditions that cause loosening are poorly understood, in part, due to a lack of information on the mechanical behavior of the cement bone interface. The purpose of this study was to determine the mechanical behavior of the cement-bone interface due to mixed-mode (combined tension and shear) loading and to develop a failure model for the cement bone interface. Laboratory tests of machined cement-bone test specimens were performed with mixed-mode loading conditions (loading angles of 22.5 degrees, 45 degrees, and 67.5 degrees) to determine the mechanical response in the pre-yield and post-yield state. After accounting for the quantity of interdigitated bone as a covariate, the mixed-mode data were combined with previous tension (0 degrees) and shear data (90 degrees) to develop a failure model for the cement bone interface. The strength of the interface was positively correlated with the quantity of interdigitated bone (r2 = 0.70, 0.53, 0.49, for 22.5 degrees, 45 degrees, and 67.5 degrees, respectively). There was a significant increase in failure strength (P < 0.001) with increasing mixed-mode angle. When all data were incorporated into an elliptical failure criterion, the average error between the actual and predicted strength was 33%. These results can now be incorporated into constitutive models of the cement bone interface to determine the initiation and progression of interface failure in cemented total hip replacements.

Results of high-dose therapy for 1000 patients with multiple myeloma: durable complete remissions and superior survival in the absence of chromosome 13 abnormalities.

High-dose therapy (HDT) has increased complete remission (CR) rates and survival in multiple myeloma (MM). We now report on continuous CR (CCR) and associated prognostic factors in 1000 consecutive patients receiving melphalan-based tandem HDT. Five-year CCR was 52% among 112 CR patients without chromosome 13 (triangle up13) abnormalities and with beta-2-microglobulin

Mechanical strength of the cement-bone interface is greater in shear than in tension.

The objective of this study was to determine the relative mechanical properties of the cement-bone interface due to tensile or shear loading. Mechanical tests were performed on cement-bone specimens in tensile (n = 51) or shear (n = 55) test jigs under the displacement control at 1 mm/min until complete failure. Before testing, the quantity of bone interdigitated with the cement was determined and served as a covariate in the study. The apparent strength of the cement-bone interface was significantly higher (p < 0.0001) for the interface when loaded in shear (2.25 MPa) when compared to tensile loading (1.35 MPa). Significantly higher energies to failure (p < 0.0001) and displacement before failure (p < 0.01) were also determined for the shear specimens. The post-yield softening response was not different for the two test directions. The data obtained herein suggests that cement-bone interfaces with equal amounts of tensile and shear stress would be more likely to fail under tensile loading.

Antitumor activity of thalidomide in refractory multiple myeloma.

BACKGROUND: Patients with myeloma who relapse after high-dose chemotherapy have few therapeutic options. Since increased bone marrow vascularity imparts a poor prognosis in myeloma, we evaluated the efficacy of thalidomide, which has antiangiogenic properties, in patients with refractory disease. METHODS: Eighty-four previously treated patients with refractory myeloma (76 with a relapse after high-dose chemotherapy) received oral thalidomide as a single agent for a median of 80 days (range, 2 to 465). The starting dose was 200 mg daily, and the dose was increased by 200 mg every two weeks until it reached 800 mg per day. Response was assessed on the basis of a reduction of the myeloma protein in serum or Bence Jones protein in urine that lasted for at least six weeks. RESULTS: The serum or urine levels of paraprotein were reduced by at least 90 percent in eight patients (two had a complete remission), at least 75 percent in six patients, at least 50 percent in seven patients, and at least 25 percent in six patients, for a total rate of response of 32 percent. Reductions in the paraprotein levels were apparent within two months in 78 percent of the patients with a response and were associated with decreased numbers of plasma cells in bone marrow and increased hemoglobin levels. The microvascular density of bone marrow did not change significantly in patients with a response. At least one third of the patients had mild or moderate constipation, weakness or fatigue, or somnolence. More severe adverse effects were infrequent (occurring in less than 10 percent of patients), and hematologic effects were rare. As of the most recent follow-up, 36 patients had died (30 with no response and 6 with a response). After 12 months of follow-up, Kaplan-Meier estimates of the mean (+/-SE) rates of event-free survival and overall survival for all patients were 22+/-5 percent and 58+/-5 percent, respectively. CONCLUSIONS: Thalidomide is active against advanced myeloma. It can induce marked and durable responses in some patients with multiple myeloma, including those who relapse after high-dose chemotherapy.

Protein fold recognition score functions: unusual construction strategies.

We describe two ways of optimizing score functions for protein sequence to structure threading. The first method adjusts parameters to improve sequence to structure alignment. The second adjusts parameters so as to improve a score function's ability to rank alignments calculated in the first score function. Unlike those functions known as knowledge-based force fields, the resulting parameter sets do not rely on Boltzmann statistics, have no claim to representing free energies and are purely constructions for recognizing protein folds. The methods give a small improvement, but suggest that functions can be profitably optimized for very specific aspects of protein fold recognition. Proteins 1999;36:454-461.

Collection of peripheral blood stem cells after a preceding autograft: unfavorable effect of prior interferon-alpha therapy.

Eighty-eight previously autografted (78 transplanted twice and 10 once) myeloma patients who had no cryopreserved stem cells available for possible future use received G-CSF for mobilization of stem cells. One-fourth of the patients had progressive disease at the time of apheresis. All patients had received 200 mg/m2 melphalan for the first transplant. The interval between the preceding transplant and the harvest was 5-68 months (median 29). A total of 0.46-9.16 (median 3.03) x 10(6) CD34+ cells/kg were collected. More than 2 x 10(6)/kg CD34+ cells were collected in 76% of the patients, and > or = 5 x 10(6)/kg in 14%. On multivariate analysis, patients with platelet counts of > or = 200 x 10(9)/l (P < 0.0001), those who had not received any myelosuppressive chemotherapy between the last transplant and the collection (P = 0.02), and those who had received interferon-alpha for < or = 6 months (P = 0.03) had better collections. Eleven of 12 patients autografted with these cells had prompt neutrophil recovery (median 10 days to 0.5 x 10(9)/l) but recovery to 50 x 10(9)/l platelets was delayed or incomplete in 11 of 12. We conclude that it is possible to harvest peripheral blood stem cells with G-CSF stimulation in patients who have been autografted previously. Limited data suggest that platelet recovery may be suboptimal when these cells are used. These findings have practical implications for patients with malignant diseases in remission after autografting who may be candidates for future salvage therapy but have no stem cells stored, and for patients with chronic myeloid leukemia who are on long-term interferon-alpha therapy to attain cytogenetic remission for eventual collection of normal stem cells.