Glass fibre reinforced versus multistranded bonded orthodontic retainers: a 2 year prospective multi-centre study.

The objective of this study was to compare glass fibre reinforced (GFR) with multistranded bonded orthodontic retainers in terms of success rate and periodontal implications. A 2 year parallel study was conducted of 184 patients scheduled to receive bonded retainers in the upper and lower anterior segments. In three centres, the patients (mean age 14 years; 90 males and 94 females) were sequentially assigned to receive GFR retainers containing 500 unidirectional glass fibres (GFR500), 1000 unidirectional glass fibres (GFR1000), or multistranded retainers (gold standard). Retainer failures and periodontal conditions were monitored every 6 months. In a control group of 90 subjects without retainers, periodontal conditions were examined (negative control). Of the 274 recruited patients, 15 dropped out during the 2 year study period. Kaplan-Meier plots were drawn to assess survival of the different retainers. The Mantel-Cox log-rank test was used to identify significant differences in survival functions among the groups. Repeated measures analysis of variance and appropriate post hoc tests were adopted to evaluate periodontal conditions over time. GFR retainers showed unacceptably high failure rates in comparison with multistranded retainers (51 versus 12 per cent). The most significant periodontal conditions were found in patients with GFR retainers with no significant differences between the GFR500 and the GFR1000 group for any parameter at any time point. Subjects without retainers showed significantly lower levels of gingival inflammation and plaque accumulation when compared with patients in any retainer group. Multistranded retainers should remain the gold standard for orthodontic retention, although periodontal complications are common. The use of GFR retainers should be discouraged in daily practice.

Expression of p14ARF, p16INK4a and p53 in relation to HPV in (pre-)malignant squamous skin tumours.

Studies in cervical dysplasia have reported overexpression of the tumour suppressors p14 and p16 - and absence of p53 - in high-risk human papilloma virus (HPV)- associated lesions. In skin carcinogenesis, the relation between these tumour suppressors and HPV remain unclear. We evaluated the expression of the tumour suppressors p14, p16 and p53 in pre-malignant and malignant squamous skin tumours, and its relation with risk factors for skin carcinogenesis (HPV, immune status and sun exposure). We performed immunohistochemical stainings for p14, p16 and p53 on paraffin embedded material of 71 pre-malignant squamous skin lesions and 34 squamous cell carcinomas, from 52 renal transplant recipients (RTRs) and 53 immunocompetent individuals. PCR-based assays were used for detection and genotyping of beta-papilloma virus (beta-PV) types and mucosal HPV types. P14 expression was independent of the expression of p16 and p53, irrespective of immune status and skin site. In 49 of 105 specimens (46.6%), one or more beta-PV types were detected. We found no significant association between p14, p16 or p53 protein expression and overall presence of beta-PV, irrespective of immune status. There was a significant association between presence of beta-PV and lesions from sun-exposed skin sites in the RTRs (P = 0.002). We conclude that in skin carcinogenesis, relations between the herein studied tumour suppressors and HPV are different from what one would expect based on findings in cervical neoplasia. P14, p16 and p53 expressions are independent of immune status. Our data indicate that in immunosuppressed patients, beta-PV together with ultraviolet radiation act synergetic in promoting carcinogenesis.

Evaluation of urinary biomarkers of exposure to benzene: correlation with blood benzene and influence of confounding factors.

PURPOSE: trans,trans-Muconic acid (t,t-MA) is generally considered as a useful biomarker of exposure to benzene. However, because of its lack of specificity, concerns about its value at low level of exposure have recently been raised. The aim of this study was (a) to compare t,t-MA, S-phenylmercapturic acid (SPMA) and benzene (B-U) as urinary biomarkers of exposure to low levels of benzene in petrochemical workers and, (b) to evaluate the influence of sorbic acid (SA) and genetic polymorphisms of biotransformation enzymes on the excretion of these biomarkers. METHOD: A total of 110 workers (including 24 smokers; 2-10 cigarettes/day) accepted to take part in the study. To assess external exposure to benzene, air samples were collected during the whole working period by a passive sampling device attached close to the breathing zone of 98 workers. Benzene was measured in blood (B-B) samples taken at the end of the shift, and was considered as the reference marker of internal dose. Urine was collected at the end of the shift for the determination of B-U, SPMA, t,t-MA, SA and creatinine (cr). B-U and B-B were determined by head-space/GC-MS, SPMA and SA by LC-MS, t,t-MA by HPLC-UV. RESULTS: Most (89%) personal measurements of airborne benzene were below the limit of detection (0.1 ppm); B-B ranged from <0.10 to 13.58 mug/l (median 0.405 microg/l). The median (range) concentrations of the urinary biomarkers were as follows: B-U 0.27 microg/l (<0.10-5.35), t,t-MA 0.060 mg/l (<0.02-0.92), SPMA 1.40 microg/l (0.20-14.70). Urinary SA concentrations ranged between <3 and 2,211 microg/l (median 28.00). Benzene concentration in blood and in urine as well as SPMA, but not t,t-MA, were significantly higher in smokers than in non-smokers. The best correlation between B-B and urinary biomarkers of exposure were obtained with benzene in urine (microg/l r = 0.514, P < 0.001; microg/g cr r = 0.478, P < 0.001) and SPMA (microg/l r = 0.495, P < 0.001; microg/g cr r = 0.426, P < 0.001) followed by t,t-MA (mg/l r = 0.363, P < 0.001; mg/g cr r = 0.300, P = 0.002). SA and t,t-MA were highly correlated (r = 0.618, P < 0.001; corrected for cr r = 0.637). Multiple linear regression showed that the variation of t,t-MA was mostly explained by SA concentration in urine (30% of the explained variance) and by B-B (12%). Variations of SPMA and B-U were explained for 18 and 29%, respectively, by B-B. About 30% of the variance of B-U and SPMA were explained by B-B and smoking status. Genetic polymorphisms for biotransformation enzymes (CYP2E1, EPHX1, GSTM1, GSTT1, GSTP1) did not significantly influence the urinary concentration of any of the three urinary biomarkers at this low level of exposure. CONCLUSION: At low levels of benzene exposure (<0.1 ppm), (1) t,t-MA is definitely not a reliable biomarker of benzene exposure because of the clear influence of SA originating from food, (2) SPMA and B-U reflect the internal dose with almost similar accuracies, (3) genetically based inter-individual variability in urinary excretion of biomarkers seems negligible. It remains to assess which biomarker is the best predictor of health effects.

A panel of p16(INK4A), MIB1 and p53 proteins can distinguish between the 2 pathways leading to vulvar squamous cell carcinoma.

Two pathways leading to vulvar squamous cell carcinoma (SCC) exist. The expression of proliferation- and cell-cycle-related biomarkers and the presence of high-risk (hr) HPV might be helpful to distinguish the premalignancies in both pathways. Seventy-five differentiated vulvar intra-epithelial neoplasia (VIN)-lesions with adjacent SCC and 45 usual VIN-lesions (32 solitary and 13 with adjacent SCC) were selected, and tested for hr-HPV DNA, using a broad-spectrum HPV detection/genotyping assay (SPF(10)-LiPA), and the immunohistochemical expression of MIB1, p16(INK4A) and p53. All differentiated VIN-lesions were hr-HPV- and p16-negative and in 96% MIB1-expression was confined to the parabasal layers. Eighty-four percent exhibited high p53 labeling indices, sometimes with parabasal extension. Eighty percent of all usual VIN-lesions were hr-HPV-positive, p16-positive, MIB1-positive and p53-negative. Five (of seven) HPV-negative usual VIN lesions, had an expression pattern like the other HPV-positive usual VIN lesions. In conclusion, both pathways leading to vulvar SCC have their own immunohistochemical profile, which can be used to distinguish the 2 types of VIN, but cannot explain differences in malignant potential.

Improved identification of malignant cells in serous effusions using a small, robust panel of antibodies on paraffin-embedded cell suspensions.

OBJECTIVE: To evaluate the expression of these markers individually and to find out which markers would be the most effective in a diagnostic panel to reliably discriminate these lesions. STUDY DESIGN: Sections from cell blocks of these fluids were stained with antibodies against calretinin, EMA, HMFG-2, BerEp4, B72.3 and CEA. A preliminary diagnosis was formulated based on cytomorphologic criteria. Subsequently, results of all 6 immunocytochemical stainings were evaluated, the most effective diagnostic pane of antibodies was proposed and staining results using this panel were compared to results obtained by solely cytomorphologic evaluation and to the ultimate diagnosis. RESULTS: Additional immunocytochemical staining with the proposed panel of calretinin, EMA, HMFG-2 and CEA improved sensitivity for malignancy in general from 78% to 96% and specificity from 73% to 91%. Sensitivity for malignant mesothelioma increased from 45% to 91%, with an increase in specificity from 87% to 96%. Sensitivity for adenocarcinoma decreased slightly from 100% to 92%, but specificity increased from 86% to 100%. Overall, diagnostic accuracy increased from 76% to 94%. CONCLUSION: Immunocytochemical staining of standardized cell block reparations of serous fluid cells with a small panel of 4 antibodies significantly improves diagnostic results compared to cytomorphologic evaluation alone.

Objective assessment of cancer biomarkers using semi-rare event detection.

Objective and reproducible assessment of cancer biomarkers may be performed using rare event detection systems. Because many biomarkers are not true 'rare events', in this study a semi-rare event detection system was developed. The system is capable of assigning a discriminant score to detected positive cells, expressing the extent and intensity of the immunocytochemical staining. A gallery image is constructed showing the diagnostically most interesting cells as well as quantitative data expressing the biomarker staining pattern. To increase scanning speed, an adaptive scanning strategy is studied in which scanning is aborted when a sufficient number of positive cells has been identified. System performance was evaluated using liquid based cervical smears, stained with an antibody directed against p16(INK4a) tumor suppressor protein. Overexpression of p16(INK4a) in cervix is related to high-risk HPV infection, which is associated with carcinogenesis. Reproducibility of the system was tested on specimens containing limited positivity. Quantitative analysis was evaluated using 10 cases within normal limits and 10 high grade lesions. The system was highly reproducible in detecting positive cells and in calculating discriminant scores (average CV 0.7%). Quantitative features were significantly increased in high grade lesions (p<0.001). Adaptive scanning decreased scanning time with only minor impact on scanning results. The system is capable of automated, objective and reproducible assessment of biomarker expression and may be useful for a variety of applications.

Two-piece implants with turned versus microtextured collars.

Implant companies have been promoting two-piece implants with microtextured collars in the interest of hard tissue preservation and/or soft tissue integration. However, this rationale may not be justified. Based on comparative studies currently available, it is unclear whether microroughened implant necks reduce crestal bone loss. A possible effect may be overruled by the establishment of a biologic width or by other factors influencing crestal bone remodeling. In addition, the orientation and attachment of the collagen fibers in the peri-implant mucosa are a little different because the surface roughness varies at the level of the implant neck. The clinician should be cautious when using these modified implants because the impact of microtextured collars on the initiation and progression of peri-implant pathology is currently unknown.

The prognostic value of endogenous hypoxia-related markers for head and neck squamous cell carcinomas treated with ARCON.

BACKGROUND AND PURPOSE: Hypoxic radioresistance is an important cause for treatment failure in a number of tumor types including head and neck cancers. Recent studies suggest that outcome can be improved by oxygenation modifying treatments such as ARCON. A robust endogenous marker of hypoxia might be a valuable aid to select patients for such treatments. The aim of this investigation was to study associations between the putative endogenous hypoxia markers CA-IX, Glut-1 and Glut-3 and clinical tumor and patient characteristics and to evaluate the prognostic value of these markers. PATIENTS AND METHODS: Tumor biopsies from 58 patients treated with ARCON in a phase II trial were included. Tumor sections were immunohistochemically stained for CA-IX, Glut-1 and Glut-3. Sections were scored for relative tumor area stained by the markers (CA-IX and Glut-3) and for intensity of staining (Glut-1 and Glut-3). Further, sections were stained for CD34, an endothelial marker to assess microvascular density. RESULTS: Staining of CA-IX and Glut-3 was observed at some distance from vessels and adjacent to necrosis. Glut-1 staining was generally very diffuse. The distribution of clinical characteristics was equal between tumors with high and low marker expression. Significant differences were found for locoregional control (P = 0.04) and for freedom of distant metastases (P = 0.02) in favour of patients with high CA-IX positivity (>25% of tumor area). High Glut-3 expression was associated with a better locoregional control (P = 0.04). Higher Glut-1 intensity was associated with an increased rate of distant metastases (P = 0.0005) and a worse overall survival (P = 0.001). CONCLUSIONS: The inconsistent associations with outcome of CA-IX and the glucose transporters indicate that different factors play a role in up-regulation of these markers. Compared to studies with conventional treatment, the correlation between CA-IX expression and Glut-3 expression and outcome was reversed after treatment with ARCON. This does not support the potential of any of these proteins as very specific and robust hypoxia markers.

Treatment results of patients with a squamous cell carcinoma of the buccal mucosa.

The purpose of this study was to evaluate outcome and value of follow-up of squamous cell carcinoma (SCC) of the buccal mucosa in patients treated at the Radboud University Nijmegen Medical Centre, The Netherlands. A longitudinal cohort study was performed involving 32 patients treated with curative intent (surgery on indication followed by radiotherapy) for SCC of the buccal mucosa from 1987 to 2002, with a minimum follow-up of three years. The prognosis of SCC of the buccal mucosa is comparable to other sites of the oral cavity. The success rate of therapy for a local and/or regional recurrence is very limited. Patients with a second primary tumour (SPT) can be cured if the tumour is detected in an early stage. Routine follow-up used to detect local recurrence or SPT has almost no value after five years and seems of limited value after three years.

Intratumoral recombinant human interleukin-12 administration in head and neck squamous cell carcinoma patients modifies locoregional lymph node architecture and induces natural killer cell infiltration in the primary tumor.

The objective of this study was to evaluate the histologic and immunohistopathologic effects of intratumorally given recombinant human interleukin-12 on the immune cells in the primary tumors and regional lymph nodes. Ten previously untreated patients with head and neck squamous cell carcinoma (HNSCC) were injected in the primary tumor twice to thrice, once weekly, at two dose levels of 100 or 300 ng/kg, before surgery. These patients were compared with 20 non-IL-12-treated control HNSCC patients. In the primary tumor, the number of CD56+ natural killer (NK) cells was increased in IL-12-treated patients compared with control patients. In some IL-12-treated patients, an impressive peritumoral invasion of CD20+ B cells was noticed. No differences were seen in the CD8+ or CD4+ T lymphocytes. Interestingly, major differences were apparent in the architecture of the enlarged lymph nodes of IL-12-treated patients; in particular, the distribution of B cells differed and fewer primary and secondary follicles with smaller germinal centers were observed. In addition, a decrease of dendritic cell lysosyme-associated membrane glycoprotein-positive cells in the paracortex was noted, resulting in a reduction of paracortical hyperplasia. In the lymph nodes, especially the CD56+ NK cells but also the CD8+ and CD4+ T lymphocytes, produced a high amount of IFN-gamma. Patients, irrespectively of IL-12 treatment, with a high number of CD56+ cells in the primary tumor had a better overall survival than those with a low number. In conclusion, after i.t. IL-12 treatment in HNSCC patients, the largest effect was seen on the NK cells, with a higher number in the primary tumor and a high IFN-gamma mRNA expression in the lymph nodes. Significant effects were noted on B cells, with altered lymph node architecture in every IL-12-treated patient and excessive peritumoral infiltration in some patients.

Pimonidazole binding and tumor vascularity predict for treatment outcome in head and neck cancer.

Hypoxia is associated with tumor aggressiveness and is an important cause of resistance to radiation treatment. Assays of tumor hypoxia could provide selection tools for hypoxia-modifying treatments. This study correlated the exogenous 2-nitroimidazole hypoxia marker 1-[(2-hydroxy-3-piperidinyl)propyl]-2-nitroimidazole hydrochloride (pimonidazole) with the endogenous hypoxia-related marker carbonic anhydrase 9 (CA9) and with vascular parameters using immunohistochemical techniques and a computerized image analysis system. Tumor biopsies were obtained from patients with head and neck carcinomas that were potential candidates for a Phase II trial with accelerated radiotherapy combined with carbogen and nicotinamide (ARCON). If, after completion of the diagnostic workup, the eligibility criteria were met and informed consent was obtained, patients were treated with ARCON. Those patients that were not eligible or refused ARCON were treated with radiotherapy, surgery, or a combined modality. Forty-three biopsies were analyzed, and the results were related with treatment outcome. The distribution patterns of pimonidazole and CA9 were similar, although the CA9 signal was generally observed already at shorter distances from blood vessels. There was a weak but significant correlation between the relative tumor areas positive for pimonidazole binding and areas with CA9 expression. Locoregional tumor control was significantly lower for patients who had hypoxic tumors or tumors with low vascular density. The 2-year control rates were 48 versus 87% for tumors with high and low pimonidazole binding levels (stratified by median, P = 0.01) and 48 and 88% for tumors with low and high vascular density (stratified by median, P = 0.01). These associations disappeared in the subgroup of patients treated with ARCON. There was no relationship between the level of CA9 expression and treatment outcome. It is concluded that pimonidazole binding and vascular density can predict treatment outcome in head and neck cancer and may be useful as selection tools for hypoxia-modifying treatments. Pimonidazole and CA9 demonstrate concordant staining patterns, but the latter is a less specific marker for hypoxia.

INK4-ARF and p53 mutations in metastatic cutaneous squamous cell carcinoma: case report and archival study on the use of Ink4a-ARF and p53 mutation analysis in identification of the corresponding primary tumor.

So far, histopathologic, immunohistochemical and molecular properties of metastatic cutaneous squamous cell carcinomas (CSCCs) are relatively unexplored. In patients with multiple CSCCs, as for instance renal transplant recipients (RTRs), it might prove difficult to identify the primary tumor responsible for metastasis. We report a case of an RTR with multiple CSCCs, one of which metastasized. By using p53 and INK4a-ARF mutation analysis, we identified the responsible primary tumor due to an identical mutation in exon 2 of the INK4a-ARF locus. Archival study yielded 14 cases of metastatic CSCC (present case included). In only 8 of 14 metastases, DNA quality was sufficient to perform PCR reactions. In 7 of 8 metastases, either an INK4a-ARF (6 of 8 cases) and/or p53 (3 of 8 cases) mutation was present. In 6 of 7 cases, the corresponding primary could be identified by an identical mutation in p53 and/or INK4a-ARF. In conclusion, molecular analysis using a combination of p53 and INK4a-ARF mutation analysis can identify the corresponding primary skin tumor in case of CSCC metastases in the majority of cases. This is facilitated by the high frequency of these mutations in metastatic CSCC when compared with frequency spectra reported in the literature in primary CSCCs. The major limitation was formed by insufficient DNA quality in archival tissue.

Interleukin-12 has no effect on vascular density, perfusion, hypoxia and proliferation of an implanted human squamous cell carcinoma xenograft tumour despite up-regulation of ICAM-1.

BACKGROUND: Interleukin-12 is an anti-angiogenic and antitumor agent in many transplanted murine tumour models. In a previous clinical study in head and neck squamous cell carcinoma patients treated with rhIL-12 the tumour turned pale, after an initial reddening. The aim of this study was to investigate the effects of rmIL-12 on the vasculature, blood perfusion, hypoxia and proliferation of tumour cells in an implanted human head and neck squamous cell carcinoma xenograft tumour, with a relatively large diameter, in Balb/c nu/nu mice over time. MATERIALS AND METHODS: Established human squamous cell carcinoma xenograft tumours were intratumorally injected for 3 days with either 200 ng rmIL-12 or PBA. Mice were sacrificed at 4 different time points (between 8 hours and 8 days after the last injection), after administration of Pimonidazole, BrdUrd and Hoechst 33342. The tumour sections were quantitatively analysed with a semi-automatic method based on a computerised digital image analysis system, after immunohistochemical staining. RESULTS: Despite a faster and higher up-regulation of anti-mouse ICAM-1 in the IL-12-treated tumours, no significant differences in vascular density, perfusion fraction, hypoxic fraction and BrdUrd labelling index were detected between IL-12-treated tumour and control tumours. CONCLUSION: We suggest that the main reason why the observation made in humans could not be confirmed in this mice study is the combination of a lack of an intact immune system in the Balb/c nu/nu mice and a relatively large tumour with probably a lot of mature vessels.

Intratumoral administration of recombinant human interleukin 12 in head and neck squamous cell carcinoma patients elicits a T-helper 1 profile in the locoregional lymph nodes.

The objective of this Phase II study was to evaluate the pharmacodynamic and immune effects of intratumorally administered recombinant human interleukin-12 (IL-12) on regional lymph nodes, primary tumor, and peripheral blood. Ten previously untreated patients with head and neck squamous cell carcinoma were injected in the primary tumor two to three times, once/week, at two dose levels of 100 or 300 ng/kg, before surgery. We compared these patients with 20 control (non-IL-12-treated) patients. Toxicity was high, with unexpected dose-limiting toxicities at the 300 ng/kg dose level. Dose-dependent plasma IFN-gamma and IL-10 increments were detected. These cytokine levels were higher after the first injection than after the subsequent injections. A rapid, transient reduction in lymphocytes, monocytes, and all lymphocyte subsets, especially natural killer cells, was observed, due to a redistribution to the lymph nodes. In the enlarged lymph nodes of the IL-12-treated patients, a higher percentage of natural killer cells and a lower percentage of T-helper cells were found compared with control patients. The same pattern was detected in the infiltrate in the primary tumor. Real-time semiquantitative PCR analysis of peripheral blood mononuclear cells in the peripheral blood showed a transient decrease of T-bet mRNA. Interestingly, the peripheral blood mononuclear cells in the lymph nodes showed a 128-fold (mean) increase of IFN-gamma mRNA. A switch from the Th2 to a Th1 profile in the lymph nodes compared with the peripheral blood occurred in the IL-12-treated patients. In conclusion, in previously untreated head and neck squamous cell carcinoma patients, recombinant human IL-12 intratumorally showed dose-limiting toxicities at the dose level of 300 ng/kg and resulted in measurable immunological responses locoregionally at both dose levels.

Different chromosomal imbalances in metastasized and nonmetastasized tongue carcinomas identified by comparative genomic hybridization.

Tumors of different metastatic behavior possibly differ in genomic constitution. We identified molecular cytogenetic differences between a group of metastasized and nonmetastasized primary tongue tumors by comparative genomic hybridization. Most frequent chromosome copy number changes for metastasized and nonmetastasized tumors were +8q (100% and 71%, respectively) and +3q (56% and 43%, respectively). Metastasized tumors showed significantly more chromosome copy number changes than nonmetastasized tumors. High copy number gains were exclusively found in metastasized tumors for 3q23-qter, 5p, 12p and 13q21-q22. Genomic imbalances occurring in metastasized tumors but not in nonmetastasized tumours were +7q21 (44%), +14q (33%), and -15q (33%). The genetic constitution of primary tongue tumors that metastasize differs from tongue tumors that do not metastasize. Our data, although obtained from a relative small group of tumors, spotlights copy number gain of chromosome region 7q21 as a potential marker for metastatic behavior.

Markers for nodal metastasis in head and neck squamous cell cancer.

OBJECTIVE: To identify markers that are relevant as predictors of lymph node metastasis in head and neck squamous cell cancer. DESIGN: Expression of p53, Rb, cyclin D1, E-cadherin, and epithelial cell adhesion molecule was examined using immunohistochemical analysis and traditional histological parameters, and the correlation of these markers with the histologically verified presence of regional metastases was determined. SUBJECTS: The study sample comprised 121 patients with head and neck squamous cell cancer from whom paraffin-embedded material of primary tumors was used. RESULTS: Lymph node metastasis was correlated with the loss of expression of Rb (P =.04) and marginally correlated with the loss of expression of E-cadherin (P =.06). If the results are broken down to subsites, loss of E-cadherin expression in oral cancer (P =.04) and absence of eosinophilic infiltration in laryngeal cancer (P =.003) correlated with nodal metastasis. None of the other markers correlated. A combination of relevant parameters did not result in a much stronger correlation. CONCLUSIONS: The expression of the investigated genetic markers and histopathological features of primary tumors can supply limited information on the metastatic behavior of tumors. Although the use of markers for regional metastasis would be a welcome additional tool, these results do not warrant the use of these parameters for clinical decision making concerning the treatment of the neck in patients with head and neck squamous cell cancer.

Quantitation of Ki-67 expression in the differential diagnosis of reserve cell hyperplasia vs. small cell lung carcinoma.

OBJECTIVE: To investigate whether the detection of proliferation-associated Ki-67 antigen may be of value in differentiating between reserve cell hyperplasia (RCH) and small cell lung cancer (SCLC). STUDY DESIGN: Retrospectively, 20 Papanicolaou-stained bronchial brushes or washings from 20 patients were selected. Ten were diagnosed as RCH (and had no SCLC in follow-up) and the other 10 as SCLC (histologically confirmed). All 20 Papanicolaou-stained slides were restained with the monoclonal antibody MIB1, directed against Ki-67 antigen; that simple and reliable procedure was described recently. In each specimen 5 coherent cell groups were identified, corresponding to RCH or SCLC, respectively; photographed; and studied for Ki-67 antigen expression after MIB1 staining of the slides. At least 3 cell groups remained in each specimen. The Ki-67 labeling index (LI) of the specimens was determined as the number of MIB1-positive cells divided by the total number of cells in the remaining cell groups. RESULTS: All cases of SCLC showed a mean Ki-67 LI of at least .415 (mean .684, SD .151), whereas in the cases with RCH the mean Ki-67 LI never was more than .158 (mean .048, SD .049). The difference was highly significant (P<.001, Student's t test). Linear discriminant analysis resulted in a classifier with which we were able to discriminate correctly between SCLC and RCH in 100% of the 20 bronchial brushings and washings. CONCLUSION: The results clearly demonstrate that measuring proliferative activity in Papanicolaou-stained bronchial brushings and washings by MIB1 restaining of the slides may be of great practical value in accurately discriminating RCH from SCLC. The method is simple and can be performed in any laboratory that is able to carry out immunocytochemical staining. However, an additional (prospective) study with a series of difficult cases is necessary to confirm these findings.

Rational approach to diagnosis and treatment of ameloblastomas and odontogenic keratocysts.

We present decision trees on the treatment of cystic lesions of the jaws based on their location. We give special consideration to the treatment of potentially aggressive lesions such as odontogenic keratocysts and cystic ameloblastomas. The treatment plan is based on a retrospective study of 19 ameloblastomas and similar published studies combined with a prospective study of keratocysts.

A European network for virtual microscopy--design, implementation and evaluation of performance.

Web-based virtual microscopy has enabled new applications within pathology. Here, we introduce and evaluate a network of academic servers, designed to maximize image accessibility to users from all regions of Europe. Whole-slide imaging was utilized to digitize the entire slide set (n = 154) for the slide seminars of the 21st European Congress of Pathology. The virtual slides were mirrored to five academic servers across Europe using a novel propagation method. Functionality was implemented that automatically selects the fastest server connection in order to optimize the slide-viewing speed ( http://www.webmicroscope.net/ECP2007). Results show that during 6 months of monitoring the uptime of the network was 100%. The average viewing speed with the network was 3.1 Mbit/s, as compared to 1.9 Mbit/s using single servers. A good viewing speed (>2Mbit/s) was observed in 32 of 37 countries (86%), compared to 25 of 37 (68%) using single servers. Our study shows that implementing a virtual microscopy network spanning a large geographical area is technically feasible. By utilizing existing academic networks and cost-minimizing image compression, it is also economically feasible.