Is there a therapeutic benefit of complete lymph node dissection in melanoma patients with low tumor burden in the sentinel node?

In the case of a positive sentinel lymph node (SLN), melanoma patients are recommended to proceed to complete lymph node dissection (CLND). However, CLND for SLN-positive patients - especially with minimal tumor burden in SLN - is becoming more controversial. We analyzed the clinical course of 305 SLN-positive patients with a mean follow-up of 51.1 months by Kaplan-Meier analyses. Overall, 58/305 (17%) patients did not undergo CLND. These were compared with a matched selection of 58 comparable patients who underwent CLND. Moreover, 106/305 patients with minimal tumor burden in SLN (<0.1 mm diameter of the largest tumor deposit) were analyzed separately. Of these 106 patients, 34 did not undergo CLND, whereas 72/106 patients were treated by CLND. In the matched groups, the CLND group and the non-CLND group did not differ significantly with respect to clinical characteristics, characteristics of the primary melanoma, and histopathological parameters of SLN. There were no differences in recurrence-free survival (P=0.765) and overall survival (P=0.844). The total number of regional lymph node metastases and time to regional lymph node metastases were not significantly higher for non-CLND patients. The subgroup of patients with minimal tumor burden in SLN also did not benefit significantly from CLND. In our analyses from a single German center, we could not find any evidence for a therapeutic survival benefit for CLND after positive SLN. However, future prospective randomized trials should confirm these data.

Effect of low direct current on anaerobic multispecies biofilm adhering to a titanium implant surface.

PURPOSE: Peri-implantitis is caused by biofilm adhering to the implant. It has been shown that bactericidal electrolysis products are generated when a low direct current is applied to a titanium implant used as the anode. The hypothesis of this study was that low-current electrolysis would eradicate viable bacteria in a simulated subgingival multispecies biofilm adhering to a titanium implant surface. MATERIAL AND METHODS: Biofilms consisting of eight anaerobic species were grown on pellicle-coated titanium discs with sand-blasted, acid-etched, large-grit (SLA; Straumann, Basel, Switzerland) surface. After 40.5 hours of growth, discs were treated with 10 mA for 10 minutes in an electrolytical setup with physiological saline and gelatin. RESULTS: Low direct current at discs used as the cathode caused a reduction of three to four orders of magnitude in viable counts, while no viable bacteria were recovered from anode discs (Mann-Whitney U-test, p < .01). Confocal laser scanning microscopy in combination with a live/dead stain showed biofilm detachment at the cathode and reduced viability at the anode. CONCLUSION: Electrochemical treatment of diseased implants appears to be promising and well worth investigating further.

Regulation of NLRP3 and AIM2 inflammasome gene expression levels in gingival fibroblasts by oral biofilms.

Periodontal disease is an inflammatory condition that destroys the tooth-supporting tissues. The inflammation is initiated by oral bacteria in the form of multi-species biofilms, and is dominated by cytokines of the IL-1 family. IL-1 activation and processing is regulated by Caspase-1, within intracellular protein complexes, known as "inflammasomes". The present study employed culture supernatants of in vitro supragingival and subgingival biofilms, to challenge human GF cultures for 6h. The gene expression of inflammasome complex components was investigated by TaqMan qPCR. NLRP1 expression was not affected, whereas NLRP2 was not expressed. Supragingival biofilm challenge increased the expression of Caspase-1, the adaptor ASC, AIM2, as well as IL-1ß and IL-18, but did not affect NLRP3 expression. Subgingival biofilm challenge enhanced Caspase-1, ASC, AIM2, IL-1ß and IL-18 gene expression at lower concentrations, followed by their down-regulation at higher concentrations, which was also evident for NLRP3 expression. Hence, supragingival and subgingival biofilms differentially regulate the gene expressions of NLRP3 and AIM2 inflammasomes and their down-stream IL-1 targets. Increased inflammasome transcription in response to supragingival biofilms is commensurate with early inflammatory events in periodontal disease, whereas decreased transcription in response to subgingival biofilms corroborates the dampening of host immune responses, in favour of pathogen survival and persistence.

The RANKL-OPG system is differentially regulated by supragingival and subgingival biofilm supernatants.

Periodontitis is an inflammatory condition that destroys the tooth supporting tissues, including the alveolar bone. It is triggered by polymicrobial biofilms attaching on tooth surfaces, which can be supragingival or subgingival. Bone resorption is triggered by receptor activator of NF-κB ligand (RANKL) and blocked by its soluble decoy receptor osteoprotegerin (OPG), which are cytokines of the tumor necrosis factor ligand and receptor families, respectively. The present study aimed to comparatively investigate the effects of the Zürich in vitro supragingival and subgingival biofilm models, on RANKL and OPG gene expression in primary human gingival fibroblasts (GF) cultures. The cells were challenged with biofilm culture supernatants for up-to 24h. RANKL and OPG gene expression in the cells was analyzed by quantitative real-time polymerase chain reaction (qPCR) and their relative RANKL/OPG ratio was calculated. Both biofilm supernatants induced RANKL expression, but the subgingival caused a more pronounced up-regulation compared to the supragingival (10-fold at 6h and 100-fold at 24h). Changes in OPG expression in response to either biofilm were more limited. Accordingly, the subgingival biofilm caused a greater enhancement of the relative RANKL/OPG ratio (4-fold at 6h and 110-fold 24h). In conclusion, subgingival biofilms exhibit a stronger potency for inducing molecular mechanisms of bone resorption than supragingival biofilms, in line with their higher virulence nature for the development of periodontitis.

Oral biofilm challenge regulates the RANKL-OPG system in periodontal ligament and dental pulp cells.

Inflammatory bone destruction triggered by oral bacteria is a hallmark of chronic and apical periodontitis. Receptor activator of NF-κB ligand (RANKL) activates bone resorption, whereas osteoprotegerin (OPG) blocks its action. These are members of the tumor necrosis factor ligand and receptor families, respectively. Although individual oral pathogens are known to regulate RANKL and OPG expression in cells of relevance to the respective diseases, such as periodontal ligament (PDL) and dental pulp (DP) cells, the effect of polymicrobial oral biofilms is not known. This study aimed to investigate the effect of the Zürich in vitro supragingival biofilm model on RANKL and OPG gene expression, in human PDL and DP cell cultures, by quantitative real-time polymerase chain reaction. RANKL expression was more pronouncedly up-regulated in DP than PDL cells (4-fold greater), whereas OPG was up-regulated to a similar extent. The RANKL/OPG ratio was increased only in DP cells, indicating an enhanced capacity for inducing bone resorption. The expression of pro-inflammatory cytokine interleukin-1ß was also increased in DP, but not PDL cells. Collectively, the high responsiveness of DP, but not PDL cells to the supragingival biofilm challenge could constitute a putative pathogenic mechanism for apical periodontitis, which may not crucial for chronic periodontitis.

Comparison of classification systems in melanoma sentinel lymph nodes--an analysis of 697 patients from a single center.

BACKGROUND: In melanoma, different classification systems have been proposed that predict overall survival (OS) and recurrence-free survival (RFS) based on findings in the sentinel lymph node (SLN). The authors of this report compared the RFS and OS of 697 melanoma patients as predicted by various classification systems. METHODS: The Rotterdam system (based on the greatest dimension of the largest tumor cell deposit), the Augsburg S-classification (based on tumor penetrative depth [TPD]), and the Hannover system (based on a combination of tumor load, TPD, and invasion of the capsule) were studied in 697 consecutive melanoma patients who underwent SLN biopsy at the authors' center. RESULTS: In univariate analyses, the Rotterdam and Hannover systems (but not the S-classification) identified 1 group of SLN-positive patients that had OS and RFS similar to the OS and RFS of SLN-negative patients. The intermediate groups from all classification systems did not differ significantly with regard to RFS and/or OS from the adjacent groups. In multivariate analysis using a Cox model, the greatest dimension of the largest tumor cell deposit (cutoff point, <0.1 mm vs > or = 0.1 mm), the TPD (cutoff point, < or = 2 mm vs > 2 mm), and capsular involvement represented independent parameters for RFS; and TPD and capsular involvement also were independent parameters for OS. On the basis of these 3 parameters, a new scoring system for risk assessment in patients with melanoma is proposed that can distinguish 3 separate groups of patients that differed significantly in OS and RFS. CONCLUSIONS: Different parameters of independent prognostic significance were identified in SLNs from patients with melanoma. Combining these parameters, the prognosis of patients with melanoma was predicted more precisely by the new scoring system than by currently published classification systems.

In vitro modeling of host-parasite interactions: the 'subgingival' biofilm challenge of primary human epithelial cells.

BACKGROUND: Microbial biofilms are known to cause an increasing number of chronic inflammatory and infectious conditions. A classical example is chronic periodontal disease, a condition initiated by the subgingival dental plaque biofilm on gingival epithelial tissues. We describe here a new model that permits the examination of interactions between the bacterial biofilm and host cells in general. We use primary human gingival epithelial cells (HGEC) and an in vitro grown biofilm, comprising nine frequently studied and representative subgingival plaque bacteria. RESULTS: We describe the growth of a mature 'subgingival' in vitro biofilm, its composition during development, its ability to adapt to aerobic conditions and how we expose in vitro a HGEC monolayer to this biofilm. Challenging the host derived HGEC with the biofilm invoked apoptosis in the epithelial cells, triggered release of pro-inflammatory cytokines and in parallel induced rapid degradation of the cytokines by biofilm-generated enzymes. CONCLUSION: We developed an experimental in vitro model to study processes taking place in the gingival crevice during the initiation of inflammation. The new model takes into account that the microbial challenge derives from a biofilm community and not from planktonically cultured bacterial strains. It will facilitate easily the introduction of additional host cells such as neutrophils for future biofilm:host cell challenge studies. Our methodology may generate particular interest, as it should be widely applicable to other biofilm-related chronic inflammatory diseases.

Criteria in sentinel lymph nodes of melanoma patients that predict involvement of nonsentinel lymph nodes.

BACKGROUND: Previous studies described various criteria in sentinel lymph nodes (SLN) of melanoma patients that predict the involvement of further, nonsentinel lymph nodes (NSLN). Such criteria may facilitate the selection of patients who might benefit from a completion lymph node dissection (CLND). However, it is currently unclear which parameters are most important. METHODS: A total of 180 melanoma patients with positive SLNB and subsequent CLND were investigated. Histopathologic parameters in the SLN were systematically evaluated and compared with regard to NSLN positivity. Twenty-eight of these patients (16.0%) had positive NSLN. RESULTS: By univariate analysis several criteria with regard to tumor burden and location of melanoma cells in the SLN correlated with NSLN involvement, such as positivity by hematoxylin-eosin (H&E) staining (P < .001), largest diameter of clusters (P < .001), capsular involvement (P = .001), extranodal extension (P < .001), and tumor penetrative depth (P < .001). Multivariate analysis revealed three independent parameters: (1) positivity of the SLN by H&E staining (versus by immunohistochemistry alone), (2) relative tumor burden > 10% of total lymph node tissue, and (3) perinodal intralymphatic tumor. In 23 of 28 patients with positive NSLN the SLN was positive by H&E staining, in 15 of 28 patients the relative tumor burden was > 10%, and 13 of 28 showed perinodal intralymphatic tumor. In 5 of 28 patients with NSLN involvement, these three parameters were negative. CONCLUSIONS: Histopathologic examination of the SLN can identify patients at risk for NSLN positivity.

Prognostic significance of isolated HMB45 or Melan A positive cells in Melanoma sentinel lymph nodes.

The detection of micrometastases (defined as groups of malignant cells) in the sentinel lymph node (SLN) is an important prognostic tool in melanoma. The use of immunohistochemistry with melanocytic markers such as HMB45 and Melan A increases the detection rate of micrometastases but there are also cases with isolated immunohistochemically positive cells (IPC). To determine the prognostic significance of isolated HMB45 and/or Melan A positive cells in melanoma SLN, we compared the clinical course of 47 patients with IPC to 308 patients with negative SLN and to 122 patients with micrometastases. The mean follow-up was 38.1 months. By Kaplan-Meier analyses, relapse free survival and overall survival of patients with IPC were similar to SLN negative patients, whereas patients with micrometastases had a significantly worse relapse free survival and overall survival. In the 47 patients with IPC, 6 relapses (12.8%) and 3 melanoma-related death (6.4%) occurred, in the SLN negative patients 36 relapses (11.7%) and 17 melanoma-related deaths (5.5%), in the patients with micrometastases 46 relapses (37.7%) and 29 melanoma-related deaths (23.8%). Prognosis of patients with IPC in SLN did not correlate with type of positive staining (HMB45, Melan A, or both), capsular involvement, number of cells, presence of cytologic atypias of IPC, or tumor penetrative depth. In conclusion, with short-term follow-up IPC in melanoma SLN are without prognostic significance.

Autoimmunity as a prognostic factor in melanoma patients treated with adjuvant low-dose interferon alpha.

Interferon alpha is used for the adjuvant treatment of malignant melanoma at different dosages (high-, intermediate-, low-dose therapy). Only a minority of patients might benefit from this therapy, and markers to identify such patients are missing. A recent study suggested that melanoma patients developing autoantibodies or clinical manifestations of autoimmunity during adjuvant high-dose interferon alpha treatment had a significant survival benefit. We retrospectively reviewed 134 melanoma patients from our institution treated with adjuvant low-dose interferon alpha therapy and correlated the development of autoimmune diseases with prognosis. Interferon (IFN) therapy was routinely monitored by history, physical examination and laboratory tests before, after the first month and then after every 3 months of therapy. During a median follow up of 46.0 months (8.5-79.0 months) 28 patients (20.9%) suffered from recurrences and melanoma related deaths occurred in 16 patients (11.9%). In 20 patients (14.9%) autoimmune thyroiditis (AIT) was diagnosed during IFN therapy, one of these 20 patients developed rheumatoid arthritis later while continuing IFN therapy. Other autoimmune diseases were not observed. In 2 patients (one with AIT and one with arthritis) the autoimmune disease led to discontinuation of IFN therapy, in the other patients AIT remained subclinical or responded well to treatment while IFN therapy was continued. Kaplan-Meier analyses revealed a significant better recurrence free survival and a trend for a better overall survival for patients with AIT. Thus, autoimmunity triggered by low-dose IFN therapy appears to indicate an improved prognosis and should encourage continuation of IFN therapy.