Characterization of squamous cell carcinomas of the head and neck using methods of spatial statistics

In the present study, 53 cases of squamous cell carcinomas of the head and neck were characterized by a quantitative histological texture analysis based on principles of spatial statistics. A planar tessellation of the epithelial tumour component was generated by a skeletonization algorithm. The size distribution of the virtual cells of this planar tessellation, and the size distribution of the profiles of the tumour cell nuclei were estimated in terms of area and boundary length. The intensity, the reduced second moment function (K-function) and the pair correlation function of the point process of the centroids of the profiles of the tumour cell nuclei were also estimated. For both purposes, it is necessary to correct for edge effects, which we consider in this paper in some detail. Specifically, the point patterns of the tumour cell nuclei were considered as realizations of a point process, where the points exist only in the epithelial tumour component (the permitted phase) and not in the stroma (the forbidden phase). The methods allow to characterize each individual tumour by a series of summary statistics. The total set of cases was then partitioned into two groups: 19 cases without lymph node metastases (pN0), and 34 nodal positive cases (pN1 or pN2). Statistical analysis showed no significant differences between the intensities, the mean K-functions and the mean pair correlation functions of the tumour cell nucleus profiles of the two groups. However, there were some significant differences between the sizes of the virtual cells and of the nucleus profiles of the nodal negative cases as compared to the nodal positive cases. In a logistic regression analysis, one of the quantitative nuclear size variables (mean nuclear area) was found to be a significant predictor of lymph node metastasis, in addition to tumour stage. The study shows the potential of methods of spatial statistics for objective quantitative grading of squamous cell carcinomas of the head and neck, and provides an example for modelling histological point patterns as realizations of planar point processes occupying a reference phase which is only a partial component of the total tissue.

Block bootstrap methods for the estimation of the intensity of a spatial point process with confidence bounds

This paper deals with the estimation of the intensity of a planar point process on the basis of a single point pattern, observed in a rectangular window. If the model assumptions of stationarity and isotropy hold, the method of block bootstrapping can be used to estimate the intensity of the process with confidence bounds. The results of two variants of block bootstrapping are compared with a parametric approximation based on the assumption of a Gaussian distribution of the numbers of points in deterministic subwindows of the original pattern. The studies were performed on patterns obtained by simulation of well-known point process models (Poisson process, two Matérn cluster processes, Matérn hardcore process, Strauss hardcore process). They were also performed on real histopathological data (point patterns of capillary profiles of 12 cases of prostatic cancer). The methods are presented as worked examples on two cases, where we illustrate their use as a check on stationarity (homogeneity) of a point process with respect to different fields of vision. The paper concludes with various methodological discussions and suggests possible extensions of the block bootstrap approach to other fields of spatial statistics.

Statistical analysis of reduced pair correlation functions of capillaries in the prostate gland

Blood capillaries are thread-like structures that may be considered as an example of a spatial fibre process in three dimensions. At light microscopy, the capillary profiles appear as a planar point process on sections. It has recently been shown that the observed pair correlation function g(r) of the centres of the fibre profiles on two-dimensional sections may be used to estimate the reduced pair correlation function of stationary and isotropic fibre processes in three dimensions. In the present study, we explored how this approach may be extended to statistical analysis of reduced g-functions of capillaries from multiple specimens of different groups and with replicated observations. The methods were applied to normal prostatic tissue compared with prostate cancer. Confidence intervals for the mean reduced g-functions of groups were estimated for fixed r-values parametrically using the t-distribution, and by bootstrap methods. Each estimated reduced g-function was furthermore characterized in terms of its first maximum and minimum. The mean length of capillaries per unit tissue volume was significantly higher in prostate cancer tissue than in normal prostate tissue. Significant differences between the mean reduced g-functions of malignant and benign lesions could be demonstrated for two domains of r-values. In general, bootstrap-based confidence intervals were slightly wider than parametrically estimated confidence intervals. Falsely negative lower bounds of the intervals, which sometimes arose using the parametric approach, could be avoided by the bootstrap method. Testing of group mean values for significant differences by the bootstrap method yielded more conservative results than multiple t-tests. The functional value of the first maximum of the reduced g-function and a global statistical parameter of short-range ordering was significantly reduced in the carcinoma group. Prostate cancer tissue is more densely supplied with capillaries than normal prostate tissue and the three-dimensional arrangement of the vessels differs with respect to interaction at various distance ranges. In the local approach used here, bootstrap methods can be used as a robust statistical tool for the computation of confidence intervals and group comparisons of mean reduced g-functions at specific ranges of interaction.

Mutations of the tumor suppressor gene SOCS-1 in classical Hodgkin lymphoma are frequent and associated with nuclear phospho-STAT5 accumulation

The suppressors of cytokine signaling (SOCS) are critically involved in the regulation of cellular proliferation, survival, and apoptosis via cytokine-induced JAK/STAT signaling. SOCS-1 silencing by aberrant DNA methylation contributes to oncogenesis in various B-cell neoplasias and carcinomas. Recently, we showed an alternative loss of SOCS-1 function due to deleterious SOCS-1 mutations in a major subset of primary mediastinal B-cell lymphoma (PMBL) and in the PMBL line MedB-1, and a biallelic SOCS-1 deletion in PMBL line Karpas1106P. For both cell lines our previous data demonstrated retarded JAK2 degradation and sustained phospho-JAK2 action leading to enhanced DNA binding of phospho-STAT5. Here, we analysed SOCS-1 in laser-microdissected Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL). We detected SOCS-1 mutations in HRS cells of eight of 19 cHL samples and in three of five Hodgkin lymphoma (HL)-derived cell lines by sequencing analysis. Moreover, we found a significant association between mutated SOCS-1 of isolated HRS cells and nuclear phospho-STAT5 accumulation in HRS cells of cHL tumor tissue (P < 0.01). Collectively, these findings support the concept that PMBL and cHL share many overlapping features, and that defective tumor suppressor gene SOCS-1 triggers an oncogenic pathway operative in both lymphomas.

Sex-specific telomere length profiles and age-dependent erosion dynamics of individual chromosome arms in humans

During aging, telomeres are gradually shortened, eventually leading to cellular senescence. By T/C-FISH (telomere/centromere-FISH), we investigated human telomere length differences on single chromosome arms of 205 individuals in different age groups and sexes. For all chromosome arms, we found a linear correlation between telomere length and donor age. Generally, males had shorter telomeres and higher attrition rates. Every chromosome arm had its individual age-specific telomere length and erosion pattern, resulting in an unexpected heterogeneity in chromosome-specific regression lines. This differential erosion pattern, however, does not seem to be accidental, since we found a correlation between average telomere length of single chromosome arms in newborns and their annual attrition rate. Apart from the above-mentioned sex-specific discrepancies, chromosome arm-specific telomere lengths were strikingly similar in men and women. This implies a mechanism that arm specifically regulates the telomere length independent of gender, thus leading to interchromosomal telomere variations.

Explorative statistical analysis of planar point processes in microscopy

Basic methods of explorative statistical analysis for stationary and isotropic planar point processes are briefly and informally reviewed. At the explorative level, planar point patterns may be characterized in terms of the intensity, the K-function and the pair correlation function. These second-order functions enable one to classify a given point process as completely random, clustering or repulsive. The repulsive behaviour may be quantified by an estimate of the hard-core distance. In the exploratory approach, the statistics are essentially free from model assumptions. Second-order spatial functions have been estimated to characterize genuine planar point processes in the macroscopic domain, for example in forestry, geography and epidemiology. For light microscopy and transmission electron microscopy, two situations are distinguished, which may be summarized as the genuine planar case and the stereological case. In the genuine planar case, a direct interpretation of the results of spatial statistics is feasible. Here, monolayers in cell culture, intramembranous particles on freeze fracture specimens and amacrine cells of the retina are mentioned as examples. In the stereological case, point patterns are generated by sections through 3D structures. Here the observed point patterns may arise as the centres of sectional profiles of particles, or as centres of sectional profiles of spatial fibre processes. In both situations, exploratory spatial point process statistics allow a quantitative characterization of sectional images for the purposes of group comparisons and classification. Moreover, for spatial fibre processes it has recently been shown that the observed pair correlation function of the centres of the fibre profiles is an estimate of the reduced pair correlation function of the fibre process in 3D. Hence for fibre processes a stereological interpretation of point process statistics obtained from sections is an additional option.

[Mutations of the tumor suppressor gene SOCS-1 in classical Hodgkin lymphoma are frequent and associated with nuclear phospho-STAT5 accumulation]

AIMS

Suppressors of cytokine signaling (SOCS) negatively regulate Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling involved in proliferation, survival, and apoptosis. We previously showed a loss of SOCS-1 function due to deleterious mutations in a major subset of mediastinal B-cell lymphoma (MBL). In MBL cell lines this leads to retarded JAK2 degradation and sustained phospho-STAT5 action results in enhanced DNA binding of phospho-STAT5.

METHODS

To investigate the SOCS-1 gene we laser-microdissected Hodgkin-and Reed-Sternberg (HRS) cells of 19 classical Hodgkin lymphoma (cHL) and performed sequencing analysis. To assess phospho-STAT5 status immunohistochemistry on the corresponding paraffin-embedded cHL tumor tissue was done.

RESULTS

We detected mutations of the SOCS-1 gene in HRS cells of 8 of 19 cHL samples and in 3 of 5 cHL-derived cell lines. Moreover, we found a significant association between mutated SOCS-1 of isolated HRS cells and nuclear phospho-STAT5 accumulation in HRS cells (P <0.01).

CONCLUSIONS

In conclusion, these findings support the concept that MBL and cHL share overlapping features and that defective tumor suppressor gene SOCS-1 triggers an oncogenic pathway operative in both lymphomas.

Bootstrap methods for statistical inference from stereological estimates of volume fraction

We suggest the use of bootstrap methods for inference from stereological estimates of volume fraction. An informal introduction to stereological estimation of volume fraction and to principles of bootstrap techniques is given. The bootstrap method is a robust computer-intensive resampling technique, based on independent random sampling from a data set with replacement. Bootstrap methods were used to estimate confidence intervals for volume fractions, and to test for a significant difference between estimated volume fractions from two samples. Two sampling designs are considered: independent replicated samples (visual fields) from a single object, and estimates of volume fraction from multiple independent objects. The methods are presented as worked examples on real data sets obtained from tumour pathology (mammary cancer, pancreatic cancer). The volume fraction of glandular lumina per total volume of the epithelial phase was chosen as target parameter. It indicates the degree of glandular differentiation in adenocarcinomas and is estimated as a ratio-of-means statistic with variable denominator within cases. The confidence intervals of the volume fraction estimated by the bootstrap method were slightly narrower than the parametrically calculated confidence intervals for all data sets. The outcomes of significance tests based on the bootstrap technique were unchanged as compared with classical tests based on the assumptions of normality and homoscedasticity of the data. Special attention was paid to the reproducibility of the bootstrap technique in replicated trials on the same data.

Prediction of the axillary lymph node status in mammary cancer on the basis of clinicopathological data and flow cytometry

Axillary lymph node status is a major prognostic factor in mammary carcinoma. It is clinically desirable to predict the axillary lymph node status from data from the mammary cancer specimen. In the study, the axillary lymph node status, routine histological parameters and flow-cytometric data were retrospectively obtained from 1139 specimens of invasive mammary cancer. The ten variables: age, tumour type, tumour grade, tumour size, skin infiltration, lymphangiosis carcinomatosa, pT4 category, percentage of tumour cells in G2/M- and S-phases of the cell cycle, and ploidy index were considered as predictor variables, and the single variable lymph node metastasis pN (0 for pN0, or 1 for pN1 or pN2) was used as an output variable. A stepwise logistic regression analysis, with the axillary lymph node as a dependent variable, was used for feature selection. Only lymphangiosis carcinomatosa and tumour size proved to be significant as independent predictor variables; the other variables were non-contributory. Three paradigms with supervised learning rules (multilayer perceptron, learning vector quantisation and support vector machines) were used for the purpose of prediction. If any of these paradigms was used with the information from all ten input variables, 73% of cases could be correctly predicted, with specificity ranging from 82 to 84% and sensitivity ranging from 60 to 63%. If only the two significant input variables were used, lymphangiosis carcinomatosa and tumour diameter, the prediction accuracy was no worse. Nearly identical results were obtained by two different techniques of cross-validation (leave-one-out against ten-fold cross validation). It was concluded that: artificial neural networks can be used for risk stratification on the basis of routine data in individual cases of mammary cancer; and lymphangiosis carcinomatosa and tumour size are independent predictors of axillary lymph node metastasis in mammary cancer.

Incidental carcinoma of the prostate: clinicopathological, stereological and immunohistochemical findings studied with logistic regression and self-organizing feature maps

OBJECTIVE

To identify significant predictive factors determining category T1a and T1b in incidental prostatic carcinoma with classical and neural multivariate data analysis methods.

MATERIALS AND METHODS

Incidental prostatic carcinomas diagnosed in our department during 1990-99 (66 cases) were re-examined. Besides acquiring routine clinical and pathological data the tumours were assessed by scoring immunohistochemistry for proliferative activity and p53-overexpression. Tumour vascularization (angiogenesis) and epithelial texture variables were investigated by quantitative stereology. The data were evaluated by classical statistical methods (t-test, correlation analysis, logistic regression). Moreover, self-organizing feature maps (SOMs) were applied as an exploratory approach to unsupervised data analysis by artificial neural networks.

RESULTS

The proliferative fraction, p53 overexpression of tumour cell nuclei, preoperative prostate-specific antigen value and density of capillary vascularization correlated with the Gleason score in incidental prostatic carcinoma. In a stepwise logistic regression analysis with the tumour categories T1a and T1b as dependent variables, the Gleason score and the volume fraction of epithelial cells were significant independent predictors of the tumour category. The cases could be grouped into clusters of different degrees of malignancy using SOMs.

CONCLUSIONS

Texture variables of tumour cells are of central importance for the extent of propagation in the prostate in incidental prostatic adenocarcinomas. Gleason score and quantitative stereological estimates of the volume fraction of tumour cells are significant predictors of T1a and T1b categories of incidental prostatic carcinoma. Unsupervised clustering of T1 prostate carcinoma cases by SOMs correlates well with the dichotomous classification into T1a and T1b according to the UICC.

P53 mutation but not p16/MTS1 mutation occurs in intraductal papillary mucinous tumors of the pancreas

BACKGROUND/AIMS

Intraductal papillary mucinous tumors of the pancreas are rare lesions, which typically show a benign clinical course. However, some of these tumors have a malignant nature and grow in an invasive manner. The purpose of the study was to determine the prevalence of p53-, p16/MTS1- and K-ras mutations in benign and malignant intraductal papillary mucinous tumors with intent to value their importance for tumor progression.

METHODOLOGY

Thirteen different archival tumor specimens were obtained at the Department of Pathology, University of Ulm. Three cases showed an invasive component of the tumor. Genomic DNA was extracted after laser capture microdissection of tumor cells from paraffin-embedded tissue sections. The corresponding sequences of p53 (exon 5, 6, 7, 8) and p16/MTS1 (exon 2) were amplified by polymerase chain reaction and subjected to single strand conformation polymorphism analysis. Codon 12 of K-ras was analyzed by the enrichment polymerase chain reaction-restriction fragment length polymorphism method. Positive samples were further investigated by sequencing.

RESULTS

K-ras mutations occurred in benign and malignant intraductal papillary mucinous tumors (4/13), whereas an alteration of the coding p53 gene sequence could only be detected in the intraductal and invasive component of one malignant tumor. None of the tissue specimens revealed mutations in exon 2 of p16/MTS1.

CONCLUSIONS

In contrast to K-ras mutations, alterations in the p53 gene may characterize ductal papillary mucinous carcinomas, which could be of major interest for their early diagnosis. The lack of mutations in the p16/MTS1 gene suggests that other genes may be involved in the formation of intraductal papillary mucinous neoplasias.

Genetic changes in stage pT2N0 prostate cancer studied by comparative genomic hybridization

OBJECTIVE

To identify chromosomal regions important for progression in clinically organ-confined prostate cancer, as the genetic changes underlying the development and progression of prostate cancer are poorly understood.

MATERIALS AND METHODS

Comparative genomic hybridization (CGH) was used to search for DNA sequence copy-number changes in a series of 50 primary organ-confined prostate adenocarcinomas (pT2N0) removed by radical prostatectomy.

RESULTS

CGH analysis indicated that 23 (46%) of the primary prostate adenocarcinomas showed chromosome alterations. The percentage of tumours with losses (38%) was higher than with gains (28%). Losses of 13q (24%), 8p (18%), 6q (10%), 16q (8%), 18q (6%) and 5q (6%) and gains of 17q (12%), 20q (12%), 9q (10%), 17p (8%) and 8q (6%) were the most frequent alterations. Amplifications were found at 8q24-qter. Minimal overlapping regions of loss, indicative of the presence of tumour-suppressor genes, were mapped to 13q21.1-q21.3 and 8p21.2, and minimal overlapping regions of gain, indicative of the presence of oncogenes, were found at 9q34.4-qter, 17q25-qter and 20q13.3-qter. There was a significant association between Gleason score and losses and gains (P = 0.003), and an association between chromosomal imbalance and high histological grade (P = 0.008).

CONCLUSION

These results suggest that losses or gains of DNA in these regions are important for prostate cancer progression, and document the spectrum of chromosomal alterations in stage pT2N0 of clinically organ-confined prostate cancer.

Leiomyosarcoma of the ethmoidal cells

Leiomyosarcomas of the paranasal sinuses are rare malignant tumors. A case of a 68-year-old female with leiomyosarcoma of the ethmoidal cells is presented. Since half a year she had a stuffed nose on both sides. Preoperatively, several attacks of epistaxis on the right side occurred. CT scans showed a tumor of the ethmoidal cells on the right side. The tumor was completely removed via a functional endoscopic endonasal approach and right sphenoethmoidectomy and maxillary sinus surgery. The operation was followed by a radiotherapy with 72 Gy. Up to 29 months after the operation local recurrence could not be observed. Endonasal tumor resection followed by radiotherapy in a case of leiomyosarcoma without invasion of orbit and skull base can allow tumor control.

Ki-67 immunostaining in pancreatic cancer and chronic active pancreatitis: does in vivo FDG uptake correlate with proliferative activity?

PET with 18F-FDG has been shown to be useful in the detection and staging of pancreatic cancer. However, whether FDG uptake is dependent on proliferative activity is still unclear. The aim of this prospective study was to evaluate a probable correlation between FDG uptake and proliferative activity in benign and malignant pancreatic tumors.

METHODS

Our series consisted of 23 patients with pancreatic cancer and 9 patients with chronic active pancreatitis (CAP). FDG PET was performed within 2 wk before surgery, and standardized uptake values (SUVs) were calculated for benign and malignant pancreatic tumors. Patients were selected when focally increased FDG uptake in previously known pancreatic tumors was present. Proliferation fraction was measured in tissue specimens using the anti-Ki-67 antibody MIB-1. A computer-assisted imaging system was used for quantification of nuclear Ki-67 immunostaining. Immunohistochemical findings were correlated to SUVS:

RESULTS

Pancreatic cancer showed both intense nuclear staining of Ki-67 (39% +/- 16%) and high FDG uptake (SUV = 3.6 +/- 1.6). However, no significant correlation was found between in vivo FDG uptake and Ki-67 immunoreactivity (P = 0.65). By contrast, Ki-67 nuclear staining was significantly lower (3.8% +/- 2.7%, P < 0.05) in CAP, whereas FDG uptake was in the same range as for pancreatic cancer (SUV = 3.5 +/- 1.8).

CONCLUSION

FDG uptake did not correlate with proliferative activity in pancreatic cancer. Proliferative activity was tenfold higher in malignant pancreatic tumors than in benign tumors associated with CAP, whereas FDG uptake in vivo did not differ significantly. Thus, a PET tracer indicating cellular proliferation should better differentiate between cancer and inflammatory lesions than do metabolic markers such as FDG.

Prediction of postoperative prostatic cancer stage on the basis of systematic biopsies using two types of artificial neural networks

OBJECTIVE

The choice of therapy for prostatic cancer should depend on a rational preoperative estimate of tumor stage. Artificial neural networks were used to predict postoperative staging of prostatic cancer from sextant biopsies and routinely available preoperative data.

METHODS

In group I (97 cases), nonorgan confinement (tumor stage > or =pT3a) was predicted on the basis of age and six histopathological variables from sextant biopsies. In group II (77 cases), nonorgan confinement and extraprostatic organ infiltration (tumor classification > or =pT3b) were predicted from age, four histopathological variables, the preoperative PSA level, and the total prostate volume estimated by preoperative ultrasonography. Learning vector quantization (LVQ) networks were applied for this purpose and compared to multilayer perceptrons (MLP) and linear discriminant analysis (LDA).

RESULTS

Nonorgan confinement could be predicted correctly in 90% of newly presented cases from sextant biopsy histopathology alone. A similar accuracy of predicting nonorgan confinement (83%) was obtained by combining preoperative biopsy histology with clinical data. Extraprostatic organ infiltration could be predicted correctly in 82%. The best results were obtained by LVQ networks, followed by MLP networks and LDA.

CONCLUSION

The postoperative tumor stage of prostatic cancer can be estimated with high accuracy, sensitivity and specificity from preoperative routine parameters using artificial neural networks, especially LVQ networks. The results suggest that this methodology should be evaluated in a larger prospective study.

A murine tumor progression model for pancreatic cancer recapitulating the genetic alterations of the human disease

This study describes a tumor progression model for ductal pancreatic cancer in mice overexpressing TGF-alpha. Activation of Ras and Erk causes induction of cyclin D1-Cdk4 without increase of cyclin E or PCNA in ductal lesions. Thus, TGF-alpha is able to promote progression throughout G1, but not S phase. Crossbreeding with p53 null mice accelerates tumor development in TGF-alpha transgenic mice dramatically. In tumors developing in these mice, biallelic deletion of Ink4a/Arf or LOH of the Smad4 locus is found suggesting that loci in addition to p53 are involved in antitumor activities. We conclude that these genetic events are critical for pancreatic tumor formation in mice. This model recapitulates pathomorphological features and genetic alterations of the human disease.

Cluster analysis of comparative genomic hybridization (CGH) data using self-organizing maps: application to prostate carcinomas

Comparative genomic hybridization (CGH) is a modern genetic method which enables a genome-wide survey of chromosomal imbalances. For each chromosome region, one obtains the information whether there is a loss or gain of genetic material, or whether there is no change at that region. Usually it is not possible to evaluate all 46 chromosomes of a metaphase, therefore several (up to 20 or more) metaphases are analyzed per individual, and expressed as average. Mostly one does not study one individual alone but groups of 20-30 individuals. Therefore, large amounts of data quickly accumulate which must be put into a logical order. In this paper we present the application of a self-organizing map (Genecluster) as a tool for cluster analysis of data from pT2N0 prostate cancer cases studied by CGH. Self-organizing maps are artificial neural networks with the capability to form clusters on the basis of an unsupervised learning rule, i.e., in our examples it gets the CGH data as only information (no clinical data). We studied a group of 40 recent cases without follow-up, an older group of 20 cases with follow-up, and the data set obtained by pooling both groups. In all groups good clusterings were found in the sense that clinically similar cases were placed into the same clusters on the basis of the genetic information only. The data indicate that losses on chromosome arms 6q, 8p and 13q are all frequent in pT2N0 prostatic cancer, but the loss on 8p has probably the largest prognostic importance.

Improved estimation of the pair correlation function of random sets

The texture of binary spatial structures can be characterized by second-order methods of spatial statistics. The pair correlation function, which describes the structure in terms of spatial correlation as a function of distance, is of central importance in this context. Conventionally, the pair correlation function of stationary and isotropic random sets is estimated as the ratio of the covariance to the square of volume fraction of the phase of interest. In the present paper, an improved estimator of the pair correlation function is presented, where the covariance is divided by the square of a distance-adapted estimator of volume fraction. The new estimator is explained mathematically and applied to simulated images of the Boolean model and to microscopic images from neoplastic and non-neoplastic human glandular tissues. It leads to a considerable reduction of bias and variance of estimated pair correlation functions, in particular for large distances.

Classification of spatial textures in benign and cancerous glandular tissues by stereology and stochastic geometry using artificial neural networks

Stereology and stochastic geometry can be used as auxiliary tools for diagnostic purposes in tumour pathology. Whether first-order parameters or stochastic-geometric functions are more important for the classification of the texture of biological tissues is not known. In the present study, volume and surface area per unit reference volume, the pair correlation function and the centred quadratic contact density function of epithelium were estimated in three case series of benign and malignant lesions of glandular tissues. The information provided by the latter functions was summarized by the total absolute areas between the estimated curves and their horizontal reference lines. These areas are considered as indicators of deviation of the tissue texture from a completely uncorrelated volume process and from the Boolean model with convex grains, respectively. We used both areas and the first-order parameters for the classification of cases using artificial neural networks (ANNs). Learning vector quantization and multilayer feedforward networks with backpropagation were applied as neural paradigms. Applications included distinction between mastopathy and mammary cancer (40 cases), between benign prostatic hyperplasia and prostatic cancer (70 cases) and between chronic pancreatitis and pancreatic cancer (60 cases). The same data sets were also classified with linear discriminant analysis. The stereological estimates in combination with ANNs or discriminant analysis provided high accuracy in the classification of individual cases. The question of which category of estimator is the most informative cannot be answered globally, but must be explored empirically for each specific data set. Using learning vector quantization, better results could often be obtained than by multilayer feedforward networks with backpropagation.

Duodenum-preserving pancreatic head resection in patients with benign and borderline tumors of the pancreatic head

BACKGROUND

Benign tumors of the pancreas are rare, accounting for only 1-2% of primary pancreatic lesions. Up to now, partial duodenopancreatectomy is still one of the established forms of treatment of benign tumors of the pancreas. We applied duodenum-preserving pancreatic head resection in 12 patients with benign pancreatic tumors to evaluate the feasibility, morbidity and recurrence rates after this less aggressive method.

METHODS

Between April 1984 and December 1999, 12 patients with benign and borderline tumors of the pancreatic head were operated on by duodenum-preserving pancreatic head resection.

RESULTS

All five patients with serous cystadenoma are free of recurrence 4.4 years after primary resection. One of two patients with mucinous cystadenoma and one of three patients with intraductal papillary mucinous tumor developed recurrent tumor within the former pancreatic head 5 years and 6 years, respectively, after the primary operation. Both patients were resected a second time. One of two patients with gastrinoma still has elevated serum gastrin levels. There was no hospital or long-term mortality.

CONCLUSION

For a symptomatic serous cystadenoma, duodenum-preserving pancreatic head resection is a good alternative to partial duodenopancreatectomy. In borderline tumors with malignant potential, we would rather suggest a more radical duodenum-preserving segmental resection. A video clip (3 min) is attached demonstrating the basic steps of duodenum-preserving pancreatic head resection.

Prediction of prostatic cancer progression after radical prostatectomy using artificial neural networks: a feasibility study

OBJECTIVE

To report a methodological feasibility study in a small series of patients with node-negative organ-confined prostatic cancer, using artificial neural networks to predict tumour progression after radical prostatectomy and thus help to identify high-risk patients who would benefit from adjuvant treatment.

PATIENTS AND METHODS

A group of 20 patients with pT2N0 prostatic cancer and postoperative tumour progression was compared with a control group of 20 patients with no progression, matched for age, duration of follow-up and preoperative serum prostate-specific antigen level. Histopathological data were obtained from the radical prostatectomy specimens, i.e. the Gleason score, World Health Organisation (WHO) grade and maximum diameter of the tumour transects. The volume and surface area of the epithelial tumour component and of the lumina of the neoplastic glands per unit tissue volume were estimated by morphometric methods. To predict recurrence, multilayer feedforward networks with backpropagation (MLFF-BP), two implementations of learning vector quantization (LVQ), and linear discriminant analysis (LDA) were applied. The ability of these models to correctly classify new cases was tested using the 'leave-one-out' technique.

RESULTS

Progression was predicted correctly in 85% of newly presented cases from the three routine histopathological variables alone. On the basis of the four morphometric variables alone progression was predicted correctly in 93% of cases. The use of all seven variables as input data only slightly improved the quality of prediction. The best results were obtained by the LVQ networks and LDA, followed by MLFF-BP networks.

CONCLUSIONS

In this methodological feasibility study, the progression of pT2N0 prostatic cancer after radical prostatectomy could be predicted with good accuracy, sensitivity and specificity from routine variables or morphometric texture variables using artificial neural networks. These results suggest that this approach should be assessed in a prospective study with more cases.

[Conjunctival pseudolymphoma in infectious mononucleosis]

BACKGROUND

The most frequent manifestation of an infection with Epstein-Barr virus is the mostly unilateral transient follicular conjunctivitis.

PATIENT

A 19-year-old man was evaluated for a unilateral salmon colored subconjunctival mass that had developed over one week. Additionally, the patient had painful cervical lymph nodes and a sore throat. Blood tests demonstrated a lymphocytosis and a high titer for Epstein-Barr-Virus-IgG and -IgM which was consistent with infectious mononucleosis. A biopsy form the conjunctival mass showed a mixed cellular infiltrate including lymphocytes, plasma cells, histocytes, and cells with a prominent eosinophilic nucleolus. The lesion displayed a spontaneous regression over the following 8 weeks.

CONCLUSION

Infectious mononucleosis should be considered with a conjunctival tumor which may mimic a lymphoma.

Molecular mediators of tumor angiogenesis: enhanced expression and activation of vascular endothelial growth factor receptor KDR in primary breast cancer

The progression of breast cancer growth and its ability to metastasize are associated with the process of angiogenesis. In this study, we examined the protein expression of vascular endothelial growth factor (VEGF) and its specific and functional receptor KDR in human breast tissue. We investigated a total of 13 mammary carcinomas, 3 fibroadenomas, 5 specimens with fibrocystic breast disease as well as normal (adjacent to malignant) breast tissue using immunohistochemistry and Western blot analysis. In all carcinomas examined, functional KDR protein was present independent of tumor type, tumor stage and histological grade as demonstrated by tyrosine phosphorylation analysis of KDR. When malignant tissues were compared with their neighboring non-neoplastic regions, activated KDR was found to be expressed to a much higher extent within the malignant tissue samples. In fibroadenomas, KDR was barely detectable, whereas in fibrocystic breast disease KDR expression was variable. Immunostaining of KDR was localized to endothelium and epithelium of mammary ducts in malignant and benign breast tissue, while VEGF immunoreactivity was primarily found in the endothelium and also in tumor cells and macrophages. Our data demonstrate that KDR activation is enhanced in breast cancer in vivo and emphasize the functional role of VEGF and KDR in the development of malignant breast disease.

Total, subtotal, and partial surgical removal of cervicofacial lymphangiomas

OBJECTIVES

To compare different surgical interventions for the treatment of extensive cervicofacial lymphangiomas and to define the minimal extent of surgery necessary to control disease.

DESIGN

Retrospective study. Mean +/- SD follow-up was 31+/-4 months after surgery. Surgical procedures were grouped as follows: (1) total removal, (2) subtotal removal (all cystic structures removed, small plaques of cyst walls left attached to vital structures), (3) partial removal (major cysts removed, some partially resected cystic structures left in place), and (4) incision and aspiration with subsequent compression bandage. Control of disease was defined as no recurrent or residual tumor or as recurrent or residual tumor less than 10% of initial tumor size without evidence of growth on several postoperative examinations and without clinical symptoms or aesthetic disfigurement.

PATIENTS

Twenty-one patients with cervicofacial lymphangiomas (>3 cm in maximum diameter) without thoracic involvement were evaluated. Fifteen patients were 6 years or younger and 6 were older than 6 years. No surgery was yet performed in 3 patients, for a total of 24 surgical interventions in 18 patients.

SETTING

Hospitalized care in 2 referral centers.

RESULTS

After total removal, disease was controlled in 5 of 5 cases; after subtotal removal, in 8 of 9 cases; after partial removal, in 1 of 7 cases; and after incision and aspiration with subsequent compression bandage, in 0 of 3 cases. Two complications were encountered-1 fully reversible paresis of the marginal branch of the facial nerve and 1 secondary healing.

CONCLUSIONS

Surgical removal of cervicofacial lymphangiomas is a safe treatment modality. Disease control can be achieved if all cystic structures are removed. Small plaques of cyst walls attached to vital structures may be left in place. If small cystic extensions of lymphangiomas are only opened and left in place or if lymphangiomas are only drained following compression bandage, symptomatic residual tumor or recurrence is frequent.

Tumor of the ampulla of Vater: experience with local or radical resection in 171 consecutively treated patients

HYPOTHESIS

This study was designed to evaluate prospectively oncological factors determining survival after resection of tumors of the papilla, comparing local and radical oncological resection. We hypothesized that, in malignant lesions of the ampulla, the T and N stages are major determinants of the patient's long-term outcome.

BACKGROUND DATA

The frequency of malignant lesions in adenomas of the papilla is about 26%. Villous adenoma of the ampulla is considered a premalignant lesion. Local excision has been recommended for benign adenoma and pancreatoduodenectomy for malignant lesions.

PATIENTS AND METHODS

From January 1, 1982, through June 30, 1997, 171 patients with tumors of the ampulla of Vater were surgically treated. Demographics, intraoperative factors, tumor pathological findings, and postoperative short- and long-term follow-up data were documented prospectively. Of the patients, 45 had adenoma of the papilla and 126 had malignant lesions of the ampulla.

RESULTS

Local resection was performed in 40 of the 45 patients with adenoma. In 98 of the 126 patients with malignant lesions, a radical Kausch-Whipple resection or pylorus-preserving pancreatoduodenectomy was used. Of the patients with benign adenoma, 40 had local resection and 5 had pylorus-preserving pancreatic head resection, with a hospital mortality of 0%. Thirty of 35 patients had villous adenoma, 9 (30%) of the 30 with severe dysplasia. Of the 126 patients with malignant lesions, 98 had partial pancreatoduodenectomy and 10 had ampullectomy, with an overall hospital mortality of 3.1% for patients who underwent resection. Seventy-eight of the 98 patients had an R0 resection. The 5-year survival probability for all patients who underwent resection was 84% for cancer stage I, 70% for stage II, and 27% for stage III. In 8 patients with villous adenoma and carcinoma in situ and in 10 patients with cancer in the adenoma, ampullectomy with local lymph node dissection was performed. In 4 of the patients who had villous adenoma and a carcinoma in stage pT1 N0, an R0 resection was performed, resulting in cure of cancer. On the basis of a multivariate regression analysis, the prognosis after oncological resection of cancer of the ampulla is determined by the absence of lymph node metastasis (P<.05), the absence of infiltration into the pancreatic head tissue (P<.05), and the application of an R0 resection.

CONCLUSIONS

In patients with villous adenoma of the ampulla, ampullectomy was an adequate surgical treatment. In patients with a low-risk cancer in stages pTis and pT1 N0 M0, G1 or G2, a local resection with ampullectomy including local lymph node dissection is justified. An oncological resection of cancer of the ampulla by means of a pylorus-preserving partial pancreatoduodenectomy or the Kausch-Whipple resection is the surgical procedure of choice; the 3- and 5-year survival rates were 72% and 52%, respectively, in patients with R0 resections.

Detailed marker chromosome analysis in cell line U-BLC1, established from transitional-cell carcinoma of the bladder

A permanent cell line, U-BLC1, was established from a primary transitional-cell carcinoma, TCC, of the urinary bladder. Karyotype analysis showed the line to be highly aberrant, with a near-triploid chromosome number of 68 to 73. Comparative genomic hybridization revealed some distinct differences between the primary tumor and the established cell line. Karyotype analysis showed 3 marker chromosomes with homogeneously staining regions, HSRs, in the cell line. The HSRs were isolated by microdissection and the microdissection probes were hybridized to normal metaphase chromosomes. The HSRs contain sequences known to be frequently involved in amplification in transitional-cell carcinoma of the bladder, 6p22, 7p11-p12, 9p23-pter, and one region not yet reported to be amplified in primary TCC of the bladder, 1p31-p32. A candidate-gene approach showed that in the region 7p11-p12 the EGFR locus is amplified and highly expressed.

[Radical surgery in cystadenoma of the pancreas--long-term experiences with 35 patients]

We report on 15 patients with mucinous and 19 patients with serous cystadenoma of the pancreas. Cystadenomas were more common in female patients (22/12), and CT was the most sensitive diagnostic tool. There was no mortality in the short or the long term (median 6 years); however, mucinous cystadenomas tend to recur when not treated by radical resection.

Intraductal papillary mucinous tumor of the pancreas

BACKGROUND

Since 1996 the classification of pancreatic tumors was replaced by the new World Health Organization nomenclature. Formerly mucinous cystadenomas are now distinguished between intraductal papillary mucinous tumors of the pancreas (IPMT) and mucinous cystadenomas.

METHODS

We reevaluated the pathological specimen and surgical therapy of 23 consecutive patients and followed up these patients up for 4 years in median. Between 1987 and 1997 we treated 8 patients with IPMT and 15 patients with mucinous cystadenomas.

RESULTS

Eighty-five per cent of all patients were symptomatic. Ultrasonography and computed tomography were the most sensitive diagnostic techniques. In 25%, the entire pancreas was involved with IPMT; that was not the case in any of the patients with mucinous cystadenoma. All patients were resected with no perioperative mortality. After dismissal from the hospital, all resected patients are still alive after a median follow-up of 4 years. In no patient with IPMT, but in 1 patient with mucinous cystadenoma, the tumor recurred.

CONCLUSION

Surgical resection is the treatment of choice in all cystic tumors, and the late outcome of IPMT is as good as for mucinous cystadenoma.

Expression of intercellular adhesion molecule-1 in human coronary endothelial and smooth muscle cells after stimulation with tumor necrosis factor-alpha

BACKGROUND

The intercellular adhesion molecule-1 (ICAM-1) is one of several human cell adhesion molecules that play a critical role in the early stages of postangioplasty restenosis. In this study, the in-vitro expression of ICAM-1 in human coronary endothelial cells and human coronary smooth muscle cells (SMC) after stimulation with tumor necrosis factor-alpha (TNF-alpha) was investigated.

METHODS AND RESULTS

SMC were isolated from the media of normal human coronary arteries (n = 26) up to 10 h post mortem (HCMSMC) and from human atherosclerotic coronary arteries (HCPSMC) that were extracted by thrombendarterectomy (n = 25). Endothelial cells of human coronary arteries (HCAEC) were purchased from Clonetics (Cell System, Remagen, Germany), and endothelial cells from human umbilical cord veins (HUVEC) were isolated after vaginal delivery. For investigations of the effect of TNF-alpha (2.5, 5, 10, and 20 ng/ml) on the proliferative activity of HUVEC, HCAEC, HCPSMC, and HCMSMC, serum-free media was used. After 24 h cell number and cell size distribution were measured in a cell analyzer system. The proliferation of HCPSMC and HCMSMC was increased by TNF-alpha; however, significant differences compared with controls were not reached. The proliferation of HUVEC and HCAEC was significantly reduced by TNF-alpha. For investigations of the effect of TNF-alpha (2.5, 5, 10, and 20 ng/ml) on the surface expression of ICAM-1, monoclonal anti-ICAM-1 antibodies (84H10) were used. The expression of ICAM-1 was analyzed using an immunofluorescence microscope. For flow cytometry analysis, 5 x 10(3) cells (100% gated) were analyzed using a fluorescence-activated cell sorter. In control cultures with no stimulation, the expression of ICAM-1 was positive in HCAEC, HCPSMC, HCMSMC, and HUVEC. TNF-alpha stimulated the expression of ICAM-1 in a time- and dose-dependent manner. After maximal stimulation with TNF-alpha (20 ng/ml for 24 h), the expression of ICAM-1 was stronger in HCMSMC than in HCPSMC.

CONCLUSIONS

These results suggest that the cytokine TNF-alpha regulates the expression of ICAM-1 in both human coronary endothelial cells and SMC, and could therefore play an important role in the pathophysiology of inflammatory and immune processes in restenosis after angioplasty.

[Classification of cytological smears of the cervix with neuronal methods]

BACKGROUND

Cytological smears obtained from the cervix are routinely examined under the microscope as part of screening programs for the early detection of cervical cancer. The aim of the present study was to investigate whether a simple feature extraction approach using only standard image processing techniques combined with a neural classifier would lead to acceptable results that might serve as a starting point for the development of a fully automated screening system.

MATERIALS AND METHODS

Gray-value images of 106 cervical smears (512 x 512 pixels) divided into two groups--inconspicuous (57) and atypical (49)--by an experienced pathologist on the basis of the original smears were employed to evaluate the method. From these images, 31 features quantifying properties of either the cell nucleus or the cytoplasm were extracted. These features were categorized with three different architectures of a neural classifier: learning vector quantization (LVQ), multilayer perceptron (MLP) and a single perceptron.

CONCLUSIONS

The results show a reclassification accuracy of about 91% for all three algorithms. Sensitivity was uniform at approximately 78%, and specificity varied between 75% and 91% in the leave-one-out evaluation. These very good results provide strong encouragement for further studies involving PAP scores and colour images.

[Cystic neoplasms of the pancreas: surgical therapy and chances for cure]

Between 1986 and 1997 we treated 67 patients with 68 cystic tumors of the pancreas including 17 mucinous cystadenocarcinomas, four serous cystadenocarcinomas, 15 mucinous cystadenomas, 18 serous cystadenomas, ten intraductal papillary-mucinous tumors, three solid-pseudopapillary tumors, and one cystic neuroendocrine tumor. Regarding surgical therapy our results reveal a differentiated management with respect to the histological findings. While in benign tumors a local resection is adequate the cystadenocarcinomas require an extended resection. In general there is an indication for surgical therapy in all cystic tumors of the pancreas--not only in malignant neoplasias. A nonoperative management is not justified. With a mean follow-up of 35 months the prognosis of the patients with a benign cystic tumor was excellent revealing a mortality of 0% whereas survival of the patients with a cystadenocarcinoma was 67% at five years.

Chromosomal changes during progression of transitional cell carcinoma of the bladder and delineation of the amplified interval on chromosome arm 8q

The cascade of genetic alterations leading to malignant transformation has been described for adenocarcinoma of the colon but is not established for other common tumor entities. In the present study, different stages of transitional cell carcinoma (TCC) of the bladder are analyzed by comparative genomic hybridization. A dynamic pattern of the chromosomal changes during tumor progression is described. Deletion of chromosome arm 9q is the earliest genetic alteration in pTa tumors. In stage pT1 carcinomas, losses of 9q, 9p, and 11p and gain of 1q and 8q are the most common. In addition to the changes specific for earlier stages, gain of 5p and 20q becomes prominent in carcinomas stage > or =pT2. Association analysis reveals a remarkable cooccurrence of 9p deletion with gain of 5p and 20q in > or =pT2 tumors. In order to determine more precisely the size of the amplified segment and the degree of amplification on chromosome arm 8q in stage pT1 tumors, this region was analyzed by semiquantitative PCR using polymorphic microsatellite markers. These studies revealed an up to 13-fold amplification. The common region of amplification could be narrowed down to 8q22.3 and between GAAT1A4 and D8S1834 (about 7 cM).

Modulation of Ca2+-activated K+ channels in human vascular cells by insulin and basic fibroblast growth factor

Insulin and basic fibroblast growth factor (bFGF) play an important role in the pathogenesis of atherosclerosis and have been shown to have vasodilatory effects. Since modulation of vascular ion channels determines membrane potential and thereby influences essential Ca2+-dependent intracellular pathways, we have investigated the effect of insulin and bFGF on Ca2+-activated K+ channels (BKCa) in human umbilical vein endothelial cells (HUVEC) and smooth muscle cells. The latter were obtained from either atherosclerotic plaques (SMCP) or from media segments (SMCM) of human coronary arteries. Using the patch-clamp technique, insulin (100 microU/ml) caused a significant increase in BKCa open-state probability in SMCP and HUVEC, whereas no significant changes were observed in SMCM. Basic FGF (30 ng/ml) revealed a significant increase in BKCa activity in HUVEC and a significant decrease in the BKCa open-state probability in SMCP, but caused no changes in SMCM. Thus, growth factors modulate vascular BKCa in a cell-type specific manner, which may be of importance concerning vasoactive and atherogenic effects of growth factors.

Cystic tumours of the pancreas: diagnostic accuracy, pathologic observations and surgical consequences

BACKGROUND

Cystic neoplasms of the pancreas account for only 1% of primary pancreatic lesions. However, patients with these tumors are diagnosed more frequently. Up to now, nonsurgical management is still the established form of treatment of benign cystic tumours of the pancreas.

METHODS

Between 1987 and 1996 we treated 51 patients with serous and mucinous cystadenoma and their malignant counterparts, serous and mucinous cystadenocarcinoma.

RESULTS

Eighty-five percent of the patients presented symptoms. Computed tomography and endoscopic cholangiopancreatography (ERCP) were the most sensitive diagnostic techniques; however, in three patients with serous cystadenoma and in one patient with serous cystadenocarcinoma, ERCP findings were completely normal. The tumour was resected in all but one patient. There was no perioperative mortality. After dismissal from the hospital, all patients in whom benign tumours had been resected are still alive; however, the late mortality of mucinous cystadenocarcinoma was 36% after a median follow-up of 6 years.

CONCLUSION

Surgical resection is recommended in all cystic tumours, even in serous cystic tumours, because symptoms may develop and malignant transformation to serous cystadenocarcinoma is possible.

Genetic alterations in chronic pancreatitis: evidence for early occurrence of p53 but not K-ras mutations

BACKGROUND

In patients suffering from chronic pancreatitis the risk for the development of pancreatic cancer ranges from 4 to 6 per cent. Various mutations are associated with pancreatic cancer, especially of p53 and K-ras. The incidence of these mutations in resected chronic pancreatitic tissue was investigated.

METHODS

In the present study DNA from 80 samples of tissue from patients with chronic pancreatitis was isolated and subjected to single-strand conformation polymorphism (SSCP) analysis of p53 exons 5-9 and restriction fragment length polymorphism analysis of K-ras (codon 12).

RESULTS

No mutations in the K-ras gene were detected. On SSCP analysis, eight of 80 cases of chronic pancreatitis showed alterations (two in exon 5, four in exon 6, two in exon 7). DNA sequence analysis revealed one deletion of 21 amino acids (exon 5), four polymorphisms in exon 6 with no change in the amino acid sequence, one point mutation in exon 5, and two point mutations located in the intron between exons 6 and 7.

CONCLUSION

These data show that in some cases of chronic pancreatitis mutations in the p53 gene occur without morphological evidence of pancreatic cancer.

Ca(2+)-activated K+ channels in human smooth muscle cells of coronary atherosclerotic plaques and coronary media segments

The behavior of Ca(2+)-activated K+ channels of large conductance (BKCa) in smooth muscle cells, which were obtained from atherosclerotic plaque material (SMCP) and from media segments (SMCM) of human coronary arteries, were compared using the patch-clamp technique. Voltage-clamp protocols in cell-attached patches revealed the characteristic voltage-dependent activation of BKCa in both cell groups. Single-channel conduction as 216.4 +/- 16.7 pS (n = 6) in SMCP and 199.9 +/- 6.7 pS (n = 6) in SMCM in symmetrical 140 mM K+ solutions. Using outside-out patches, external perfusion with 500 microM tetraethylammonium ions caused a typical "flickery block" of the unitary current. The selective BKCa channel inhibitor iberiotoxin (50 nM) effectively blocked BKCa, channel activity. Comparing BKCa open-state probabilities (P0) at +80 mV in cell-attached patches, a highly significant difference between SMCP (P0 = 0.1438 +/- 0.1301; n = 15) and SMCM (P0 = 0.0093 +/- 0.0044; n = 15; Kruskal-Wallis test, p < 0.001) was found. In contrast to this finding, there was no significant difference in the open-state probability of BKCa, between SMCP (P0 = 0.542 +/- 0.0237; n = 9) and SMCM (P0 = 0.0472 +/- 0.0218; n = 10; p = n.s.) using inside-out patches. The results show an interesting difference in the behavior of large conductance Ca(2+)-activated K+ channel in SMCP compared to SMCM with a significantly higher channel activity in human smooth muscle cells obtained from coronary atherosclerotic plaque material. This finding may indicate an important functional role of BKCa channels in the development of atherosclerosis.

XX-agonadism in a fetus with multiple dysraphic lesions: a new syndrome

We report on a 19-week-old fetus with a 46,XX karyotype, normal female external genitalia, complete gonadal agenesis, large encephalocele, spina bifida, and omphalocele. We postulate a new syndrome. Hitherto no consistent malformation patterns have been observed in agonadism patients. True agonadism, including even the unusual finding of an XX gonosomal status, is obviously not as rare as suggested.

Laser therapy in dogs and humans--is there a difference?

OBJECTIVE

To compare quantitatively the reduction of volume of benign prostatic hyperplasia (BPH) achieved by laser therapy in dogs and men.

PATIENTS, MATERIALS AND METHODS

Twelve mongrels, with a mean prostatic volume of 33.4 mL, underwent transurethral laser treatment using an Nd:YAG laser with an Ultraline fibre at 60 W power setting. The reduction in prostatic volume was assessed quantitatively 3 months after treatment using stereological methods. Forty patients (mean age 70.2 years, range 51-84) with symptomatic BPH (pre-operative mean prostate volume 46.3 mL) were treated under similar operative conditions with the same laser, power and fibre system. Their urinary performance was assessed before and 6 months after treatment using urinary flow rates, residual volume and a symptom score, and their prostatic volume and necrosis assessed using transrectal ultrasonography.

RESULTS

After laser treatment, the mean reduction in the dog prostate volume was 50% and in the patients was only 21%. The different impact was probably caused by anatomical differences between the human and dog prostate; the human prostate consists mainly of stromal tissue and the canine prostate of glandular epithelium.

CONCLUSIONS

The canine model gives only an approximate guide to the extent of tissue destruction that laser treatment can achieve in men with BPH. Furthermore, tissue differences between men may also affect the response to laser treatment.

High-dose diltiazem prevents migration and proliferation of vascular smooth muscle cells in various in-vitro models of human coronary restenosis

BACKGROUND

Restenosis after coronary angioplasty is considered to be caused mainly by increased migration and proliferation of smooth muscle cells (SMC). The concept of local, site-specific delivery of pharmacologic therapies has opened the door for new, high-dose drug regimes.

METHODS AND RESULTS

SMC were isolated by enzymatic disaggregation with collagenase/elastase from human coronary plaque tissue of 29 patients (pSMC) and post mortem from the coronary media of 33 corpses (mSMC). Endothelial cells were isolated from human umbilical veins by enzymatic disaggregation with collagenase/dispase. By positive reaction with antibodies against smooth muscle alpha-actin and von Willebrand factor cells were identified as SMC or endothelial cells. In proliferation studies 5-150 micrograms/ml diltiazem was added to the culture media of pSMC, mSMC and endothelial cells. After 5 days there was a significant dose-dependent inhibition of cell proliferation (for pSMC with > 50 micrograms/ml, for mSMC with > 25 micrograms/ml, and for endothelial cells with > 5 micrograms/ml). In migration studies the effect of 5-150 micrograms/ml diltiazem on the velocity of migration of pSMC was investigated over a period of 48 h. Administration of diltiazem at concentrations of 100 and 150 micrograms/ml caused a significant inhibition of the migration of pSMC. The cytoskeletal components smooth muscle alpha-actin, vimentin, and alpha-tubulin of pSMC and the expression of von Willebrand factor of endothelial cells were investigated after an incubation period of 5 days with 50 and 150 micrograms/ml diltiazem. In the transfilter coculture model the effect of 50 micrograms/ml diltiazem on mSMC was investigated after mechanical injury of cocultured endothelial cells. Administration of diltiazem at a concentration of 50 micrograms/ml inhibited the development of a neointimal proliferate in the transfilter coculture model significantly (P < 0.001).

CONCLUSIONS

A high dose of diltiazem inhibited the migratory and proliferative activities of coronary SMC significantly. In further experimental studies the effect of locally applied high doses of diltiazem on postangioplasty restenosis should be elucidated.

Nonlinear deterministic analysis of tissue texture: a stereological study on mastopathic and mammary cancer tissue using chaos theory

Signals from some dynamical systems look like stochastic processes although their latent mechanism is deterministic. When such systems show sensitive dependence on small changes of initial conditions, they are denoted as deterministic chaos. Motivated by recent advances in statistical inference methods for chaotic systems and by the concept of spatial chaos, we present a deterministic approach to the study of epithelial tissue texture. Methods for estimation of the autocorrelation function, for evaluation of the power spectrum, for attractor reconstruction, for estimation of the Lyapunov exponent and of the correlation dimension, and for the generation of surrogate data sets are outlined. In our biological example, these methods are applied to 20 cases of mastopathy as compared to 20 cases of mammary cancer. The input signals for the analysis were estimates of epithelial fraction measured at low magnification within 5100 equally spaced line segments per case perpendicular to an arbitrarily directed axis. The results suggest the existence of a low-dimensional deterministic attractor in mastopathic tissue texture, which is replaced by coloured noise in the majority of mammary carcinomas. Biological mechanisms for this finding and scale effects are discussed, and some methodological aspects and possible extensions of our approach are outlined.

Serous cystadenocarcinoma of the pancreas

The mucinous type of cystadenoma of the pancreas is known to have malignant potential, whereas the serous type is believed to be benign. Therefore, the therapeutic strategies for serous cystadenomas are less aggressive than in mucinous cystadenoma, where complete operative resection is the procedure of choice. A patient with a biopsy-proven serous cystadenocarcinoma with a lymph node metastasis is reported. Considering the reported case and a review of the literature, the origin of serous cystadenocarcinoma appears to be from cystadenoma lesions. Even if this development of cystadenocarcinoma in pre-existing serous cystadenoma lesions is a rare entity, a less aggressive treatment of this lesion should be avoided in favor of resection procedures because of the good chance of cure.