[Management of pruritus in the elderly]

BACKGROUND

Chronic pruritus (CP), a frequent (20.3%) symptom in the elderly, increases with age. It has a significant impact on the quality of life, ranking among the 50 most burdensome diseases worldwide (Global Burden of Disease Study).

OBJECTIVES

The aim is to provide an overview of the symptom CP in the elderly and to improve differentiation of underlying conditions and management of this entity.

MATERIALS AND METHODS

A literature search in PubMed was performed, using the terms 'pruritus', 'elderly' and 'gerontodermatology'.

RESULTS

The main causes of CP in the elderly are the physiologic aging process (xerosis cutis, immunosenescence, neuropathy), the increase in potentially pruritic diseases with increasing age (diabetes mellitus, chronic renal failure), and polypharmacy. Therapeutic options relate to causes, severity of pruritus, and individual patient factors (multimorbidity, impaired organ function). The recently updated S2k guideline 'Diagnosis and therapy of chronic pruritus' is helpful.

CONCLUSION

CP in the elderly is challenging for both patients and physicians. Not only the difficulty of identifying the underlying cause, but the complexity of treatment and its tolerability and practicability determines these patients' further burden.

Effect of physical cues of altered extract media from biodegradable magnesium implants on human gingival fibroblasts

Volume stable barrier membranes made of magnesium are very promising in Guided Bone Regeneration (GBR) to treat periodontal bone defects in dentistry due to their excellent biocompatibility and biodegradability. During the degradation process the cells are exposed to the alteration of various parameters, so called physical cues, involving surface alterations due to the formed corrosion layer and medium alterations arising from the dissolved corrosion products. Cell migration of human gingival fibroblasts (HGF), as a crucial parameter for optimal healing process in GBR, has been investigated on magnesium membranes and revealed that medium alterations by dissolved corrosion products have a higher impact on cell migration than surface alterations. However, the effect of each altered medium parameter on cell migration has not been adequately studied, but their roles are crucial to explain the slower migration rate on magnesium surfaces compared to titanium and tissue culture plastic surfaces. Our study investigates the single effect of Mg²⁺, Ca²⁺, H₂ and increased osmolality as well as the effect of magnesium extracts, which contain a dynamic mixture of previous parameters on cell migration, proliferation and viability of HGF. We showed that at 75 mM Mg²⁺ concentration and at 0 mM Ca²⁺, respectively, the cell migration rate is greatly reduced. In complex magnesium extract media, we found that a temporarily increased ratio of Mg²⁺ to Ca²⁺ conditioned a slow HGF migration rate. Based on these findings and the characterization of supernatants from HGF migration assays on Mg membranes, we propose, that the slower migration rate of HGF can be explained by the altered ratio of Mg²⁺ to Ca²⁺, caused by increasing concentrations of Mg²⁺ and decreasing concentrations of Ca²⁺ in the vicinity of the corroding Mg implant, combined with a constantly increased molecular hydrogen concentration in the supernatant. These results are cell type specific and should be checked carefully, if necessary, for Mg implant performance. STATEMENT OF SIGNIFICANCE: The study is providing a systematic approach to explain the main effects of extract medium parameters (physical cues) such as magnesium or calcium ion concentration, osmolality and dissolved molecular hydrogen and CO₂ in cell culture media modified by co-incubating with corroding magnesium implants on the migration rate of human gingival fibroblasts (HGF). This study uncovers for the first time the combinatory effect of slightly increased molecular hydrogen and the change in Mg²⁺/Ca²⁺ ratio on HGF cell migration.

Surgical procedure for implanting a radiotelemetry transmitter to monitor ECG, heart rate and body temperature in small Carassius auratus and Carassius auratus gibelio under laboratory conditions

Radiotelemetry provides an alternative means of obtaining physiological measurements from conscious and freely moving animals, without introducing stress artefacts. A surgical procedure is described for implanting radiotelemetry transmitters to monitor the electrocardiogram (ECG), heart rate (HR) and body temperature (BT) in small goldfish ( Carassius auratus; 50–100 g) and Prussian carp ( Carassius auratus gibelio; 100 g). This type of transmitter is commonly implanted in freely moving mice. After surgery and a recovery period of 24 h, the ECG, HR and BT were recorded in freely swimming fish within the limitations of the aquarium.

In vitro and in vivo evaluation of biodegradable, open-porous scaffolds made of sintered magnesium W4 short fibres

A cytocompatible and biocompatible, degradable, open-porous, mechanically adaptable metal scaffold made of magnesium alloy W4 melt-extracted short fibres was fabricated by liquid phase sintering. Cylindrical samples (3×5 mm) of sintered W4 short fibres were evaluated under in vitro (L929, HOB, eudiometer, weight loss) and in vivo conditions (rabbits: 6 and 12 weeks). The in vitro corrosion environment (e.g., temperature, flow, composition of corrosion solution, exposure time) significantly influenced the corrosion rates of W4 scaffolds compared with corrosion in vivo. Corrosion rates under cell culture conditions for 72 h varied from 1.05 to 3.43 mm y(-1) depending on the media composition. Corrosion rates measured in eudiometric systems for 24 h were ~24-27 times higher (3.88-4.43 mm y(-1)) than corrosion in vivo after 6 weeks (0.16 mm y(-1)). Moreover, it was found that the cell culture media composition significantly influences the ionic composition of the extract by selectively dissolving ions from W4 samples or their corrosion products. A pilot in vivo study for 6 and 12 weeks demonstrated active bone remodelling, no foreign body reaction and no clinical observation of gas formation during W4 scaffold implantation. Long-term in vivo studies need to be conducted to prove complete degradation of the W4 scaffold and total replacement by the host tissue.

Magnesium alloys as implant materials--principles of property design for Mg-RE alloys

Magnesium alloys have attracted increasing interest in the past years due to their potential as implant materials. This interest is based on the fact that magnesium and its alloys are degradable during their time of service in the human body. Moreover magnesium alloys offer a property profile that is very close or even similar to that of human bone. The chemical composition triggers the resulting microstructure and features of degradation. In addition, the entire manufacturing route has an influence on the morphology of the microstructure after processing. Therefore the composition and the manufacturing route have to be chosen carefully with regard to the requirements of an application. This paper discusses the influence of composition and heat treatments on the microstructure, mechanical properties and corrosion behaviour of cast Mg-Gd alloys. Recommendations are given for the design of future degradable magnesium based implant materials.

In vivo corrosion and corrosion protection of magnesium alloy LAE442

The aim of this study was to investigate whether the extruded magnesium alloy LAE442 reacts in vivo with an appropriate host response and to investigate how an additional magnesium fluoride (MgF(2)) coating influences the in vivo corrosion rate. Forty cylinders were machined from extruded LAE442 and 20 of these were coated additionally with MgF(2) and implanted into the medial femur condyle of adult rabbits. Synchrotron-radiation-based X-ray computed micro-tomography (SRmicroCT) was used to quantitatively analyse corrosion non-destructively in vivo and comparisons were made to magnesium degradation rates based on area measurements of the remaining metal on uncalcified sections. Blood concentrations of the alloying elements were measured below toxicological limits. The MgF(2) layer was no longer detected after 4 weeks of implantation by particle-induced gamma emission, and the MgF(2) coating reduced the blood content of alloying elements during the first 6 weeks of implantation with no elevated fluoride concentration in the adjacent bone. Histopathological examinations of liver showed in 9 out of 40 cases minimal infiltrations of heterophil granulocytes of unknown origin (5 LAE442, 4 LAE442+MgF(2)). The kidneys were mainly regular in structure. The synovial tissue showed a granular cell infiltration as a temporary observation in the LAE442+MgF(2) group after 2 weeks. No subcutaneous gas cavities were observed clinically and on postoperative X-rays in all animals. All specimens were scanned by SRmicroCT at 2, 4, 6 and 12 weeks postoperatively before uncalcified sections were performed. All magnesium implants have been observed in direct bone contact and without a fibrous capsule. Localized pitting corrosion occurred in coated and uncoated magnesium implants. This study shows that the extruded magnesium alloy LAE442 provides low corrosion rates and reacts in vivo with an acceptable host response. The in vivo corrosion rate can be further reduced by additional MgF(2) coating.

Stiffness of callus tissue during distraction osteogenesis

INTRODUCTION

The treatment of limb length discrepancies by distraction osteogenesis represents a significant challenge of predicting the load bearing capacity. Today, in vivo stiffness measurements by applying compressive, bending or torsional stress on the callus tissue are quantitative methods. Therefore, it is relevant to know how regenerating bone tissue regains its various stiffness characteristics. Knowledge of the development of each type of stiffness is important in order to prevent an over- or underestimation of the actual load bearing capacity.

HYPOTHESIS

Various types of stiffness are supposed to evolve similar during consolidation.

SUBJECTS AND METHODS

In this ex vivo study, an analysis of torsional, compressive and bending stiffness of callus tissue during consolidation was performed on 26 sheep tibiae after distraction osteogenesis.

RESULTS

This study indicates differences within the quantity of stiffness during consolidation.

DISCUSSION

Thus, in vivo stiffness measurements have to be interpreted carefully in order to prevent false estimation of the load bearing capacity of new bone.

[Biodegradable synthetic implant materials : clinical applications and immunological aspects]

In the last decade biodegradable synthetic implant materials have been established for various clinical applications. Ceramic materials such as calcium phosphate, bioglass and polymers are now routinely used as degradable implants in the clinical practice. Additionally these materials are now also used as coating materials or as microspheres for controlled drug release and belong to a series of examples for applications as scaffolds for tissue engineering. Because immense local concentrations of degradation products are produced during biodegradation, this review deals with the question whether allergic immune reactions, which have been reported for classical metallic and organic implant materials, also play a role in the clinical routine for synthetic biodegradable materials. Furthermore, possible explanatory theories will be developed to clarify the lack of clinical reports on allergy or sensitization to biodegradable synthetic materials.

Multiple strategies of Lake Victoria cichlids to cope with lifelong hypoxia include hemoglobin switching

Many fish species adapt to hypoxia by reducing their metabolic rate and increasing hemoglobin-oxygen (Hb-O(2)) affinity. Pilot studies with young broods of cichlids showed that the young could survive severe hypoxia in contrast with the adults. It was therefore hypothesized that early exposure results in improved oxygen transport. This hypothesis was tested using split brood experiments. Broods of Astatoreochromis alluaudi, Haplochromis ishmaeli, and a tilapia hybrid (Oreochromis) were raised either under normoxia (NR; 80-90% air saturation) or hypoxia (HR; 10% air saturation). The activity of the mitochondrial citrate synthase was not different between NR and HR tilapia, but was significantly decreased in HR A. alluaudi and H. ishmaeli, indicating lowered maximum aerobic capacities. On the other hand, hemoglobin and hematocrit levels were significantly higher in all HR fish of the three species, reflecting a physiological adaptation to safeguard oxygen transport capacity. In HR tilapia, intraerythrocytic GTP levels were decreased, suggesting an adaptive increase of blood-O(2) affinity. Similar changes were not found in HR H. ishmaeli. In this species, however, all HR specimens exhibited a distinctly different iso-Hb pattern compared with their NR siblings, which correlated with a higher intrinsic Hb-O(2) affinity in the former. All HR cichlids thus reveal left-shifted Hb-O(2) equilibrium curves, mediated by either decreased allosteric interaction or, in H. ishmaeli, by the production of new hemoglobins. It is concluded that the adaptation to lifelong hypoxia is mainly due to improved oxygen transport.

Biodegradable magnesium scaffolds: Part II: peri-implant bone remodeling

In this study, histomorphometrical parameters of the peri-implant bone remodeling around degrading open-porous scaffolds made of magnesium alloy AZ91D were investigated and compared with the peri-implant bone remodeling around an autologous bone transplant in the contralateral side in a rabbit model after 3 and 6 months. Osteoblast activity was displayed by collagen I (alpha 2) mRNA in situ hybridization. Major scaffold degradation was completed within 3 months after implantation showing no osteolysis around the scaffolds, both after 3 and 6 months. Enhanced formation of unmineralized extracellular matrix and an enhanced mineral apposition rate adjacent to the degrading magnesium scaffolds were accompanied by an increased osteoclastic bone surface, which resulted in higher bone mass and a tendency to a more mature trabecular bone structure around the magnesium scaffolds compared to the control. These results show that even fast-degrading magnesium scaffolds induce extended peri-implant bone remodeling with a good biocompatibility. In summary, this study shows that degrading magnesium scaffolds promote both bone formation and resorption in a rabbit model and are therefore very promising candidates for the development of novel implants in musculoskeletal surgery.

Biodegradable magnesium scaffolds: Part 1: appropriate inflammatory response

Current tissue engineering strategies focus on the replacement of pathologically altered tissues by the transplantation of cells in combination with supportive biocompatible scaffolds. Scaffolds for tissue engineering strategies in musculoskeletal research require an appropriate mechanical stability. In recent studies, considerable attention has thus been given to magnesium alloys as biodegradable implants. The aim of this study was to characterize the biocompatibility of magnesium scaffolds by the inflammatory host response. Open porous scaffolds made of the magnesium alloy AZ91D were implanted into the distal femur condyle of rabbits and were compared to autologous bone, which was transplanted into the contralateral condyle in a 3 and 6 months follow-up group. After 3 months, magnesium scaffolds were already largely degraded and most of the original magnesium alloy has disappeared. Concomitantly, a fibrous capsule enclosed the operation site. Histological analysis revealed that the magnesium scaffolds caused no significant harm to their neighboring tissues. This study shows that even fast degrading magnesium scaffolds show a good biocompatibility and react in vivo with an appropriate inflammatory host response. Magnesium alloy based implants are therefore a very promising approach in the development of mechanically suitable and open porous scaffolds for the replacement of subchondral bone in cartilage tissue engineering.

[Improved osseointegration of titanium implants after surface coating with polymers in a rabbit model]

In this study we present the first results of the investigation of polymer-coated titanium implants implanted in the proximal tibia and distal femora of New Zealand white rabbits. The results of DEXA scans, micro-CT, and histological analysis showed an increase of osseointegration. We suggest that controlled release kinetics after coupling of these polymers with BMP-2 can additionally increase osseointegration.

Comparison of various types of stiffness as predictors of the load-bearing capacity of callus tissue

The ability to predict load-bearing capacity during the consolidation phase in distraction osteogenesis by non-invasive means would represent a significant advance in the management of patients undergoing such treatment. Measurements of stiffness have been suggested as a promising tool for this purpose. Although the multidimensional characteristics of bone loading in compression, bending and torsion are apparent, most previous experiments have analysed only the relationship between maximum load-bearing capacity and a single type of stiffness. We have studied how compressive, bending and torsional stiffness are related to the torsional load-bearing capacity of healing callus using a common set of samples of bone regenerate from 26 sheep treated by tibial distraction osteogenesis. Our findings showed that measurements of torsional, bending and compressive stiffness were all suitable as predictors of the load-bearing capacity of healing callus. Measurements of torsional stiffness performed slightly better than those of compressive and bending stiffness.

In vivo corrosion of four magnesium alloys and the associated bone response

Degrading metal alloys are a new class of implant materials suitable for bone surgery. The aim of this study was to investigate the degradation mechanism at the bone-implant interface of different degrading magnesium alloys in bone and to determine their effect on the surrounding bone. Sample rods of four different magnesium alloys and a degradable polymer as a control were implanted intramedullary into the femora of guinea pigs. After 6 and 18 weeks, uncalcified sections were generated for histomorphologic analysis. The bone-implant interface was characterized in uncalcified sections by scanning electron microscopy (SEM), element mapping and X-ray diffraction. Results showed that metallic implants made of magnesium alloys degrade in vivo depending on the composition of the alloying elements. While the corrosion layer of all magnesium alloys accumulated with biological calcium phosphates, the corrosion layer was in direct contact with the surrounding bone. The results further showed high mineral apposition rates and an increased bone mass around the magnesium rods, while no bone was induced in the surrounding soft tissue. From the results of this study, there is a strong rationale that in this research model, high magnesium ion concentration could lead to bone cell activation.

[Injectable carrier system for growth factor application in minimally invasive stimulation of bone healing]

The characterization and cloning of growth factors for bone healing provide an enormous potential for minimally invasive treatment procedures for bone defects or fractures. However, the clinical application of injection vehicles for these growth factors must be made user-friendlier. In this study, two different injection vehicles were tested for their practicability and efficacy to enhance callus maturation during distraction osteogenesis. Calcium phosphate carriers showed a rather low user-friendliness and were less efficient in the animal model of distraction osteogenesis in sheep. Collagen carriers provided both a higher practicability for injection procedures and a higher efficacy.

Bone turnover during distraction osteogenesis in an experimental sheep model

Biochemical serum markers of osteoblastic activity and collagen turnover were measured in a sheep model of distraction osteogenesis. Significant increases of the bone formation marker osteocalcin were found during the first part of the consolidation phase and peaked at a time point equalling the distraction phase. Collagen turnover parameters pyridinoline and the specific type I collagen marker desoxypyridinoline consistently increased during the distraction and consolidation phases. While pyridinoline peaked at a time point similar to osteocalcin, desoxypyridinoline increased to a later stage in consolidation, indicating continuous turnover of bone-specific type I collagen. The results indicate a characteristic pattern of osteoblast cellular activation during distraction osteogenesis with possible consequences for the timing of treatment.

Use of an injectable calcium phosphate bone cement in the treatment of tibial plateau fractures: a prospective study of twenty-six cases with twenty-month mean follow-up

OBJECTIVE

To evaluate the potential benefit of a new injectable mineral bone cement (Norian SRS, Cupertino, CA, USA) for the treatment of tibial plateau fractures OTA types 41.B2-B3 and C3.

DESIGN

Prospective study with established protocol.

SETTING

University hospital; university teaching hospital.

PATIENTS

Twenty-six patients gave informed consent to participate in this study and were available for follow-up examinations. All patients had sustained intraarticular tibial plateau fracture types OTA B2-B3 and C3. All cases were followed with a mean follow-up time of 19.7 months (6 to 36 months, median eighteen months).

INTERVENTION

Twenty-five cases were treated with open reduction, osteosynthesis with screws or plate, and injection of Norian SRS in the subchondral bone defect. One case had closed reduction, screw osteosynthesis, and percutaneous cement injection.

MAIN OUTCOME MEASUREMENTS

Radiographs in two planes were evaluated prospectively at six, twelve, and twenty-six weeks postoperatively and at last follow-up using Rasmussen's radiologic score. Clinical parameters were measured at the same time intervals using Lysholm's and Tegner's knee scores.

RESULTS

Two cases required early wound revisions because of sterile drainage. Two cases developed partial loss of reduction of the fracture between four and eight weeks after surgery, requiring revision surgery in one case (total complication rate 15.3 percent). No other patients had complications, and all other fractures healed without any displacement. The high mechanical strength of the cement allowed early weight bearing after a mean postoperative period of 4.5 weeks (1 to 6 weeks).

CONCLUSIONS

An injectable mineral bone cement with high initial mechanical strength was used to fill bone defects in unstable tibial plateau fractures with good success. This material offers new perspectives in the treatment of tibial plateau fractures.

Vesicle Phases with Semipolar Additives

We examined the influence of semipolar additives on the phase behavior of mixed zwitterionic surfactant/consurfactant systems. It is shown that in these systems with increasing concentration esters like hexylacetate (HA) and ketones like hexylmethylketone (HMK) can behave both like consurfactants and like hydrocarbons. In solutions of 200 mM tetradecyldimethylamineoxide (TDMAO)/cosurfactant the additives cause first a phase transformation from the micellar L(1) phase to a lamellar L(alpha) phase. Upon further increasing concentration, the L(alpha) phase is transformed into a microemulsion. The L(alpha) phase consists of densely packed multilamellar vesicles. The vesicles are shown by electron microscopy. The multilamellar character of the vesicles is also reflected in the conductivity of the phase. It is up to 10 times lower than the conductivity of the L(1) phase. In some systems the vesicles are transformed on rest into a multidomain stacked L(alpha) phase. It is furthermore demonstrated that the two-phase L(1)/L(alpha) region in these systems is very narrow. In situations where enough HA is added to be close to the boundary of the L(1) phase, it is shown that very small amounts of cosurfactant can transform the L(1) phase into the L(alpha) phase. In extreme situations 1 mM cosurfactant is sufficient for transforming the L(1) phase with 200 mM TDMAO into the L(alpha) phase. In the investigated systems the L(alpha) phase is a highly viscoelastic fluid in which the storage modulus is 1 order of magnitude larger than the loss modulus. Besides the conventional way to prepare samples by adding all ingredients and stirring the solution intensively, all investigated systems were additionally prepared without applying any shear forces. In a surfactant/cosurfactant solution the additive was brought into the sample by diffusion. The phase behavior of both types of samples showed fundamental differences in some cases, which give insight into the influence of shear forces on these systems. Copyright 2001 Academic Press.

[Osteosynthesis of fractures of the head of the tibia in advanced age. A matched-pair analysis]

In a retrospective study we analyzed 183 patients with tibial head fractures. 15 patients were older than 60 years at the time of accident, with a mean age of 69 (62-81) years. All patients had sustained an isolated tibial plateau fracture with a split-impression fracture in 10 patients, an impression fracture in 2 patients and a bicondylar fracture in 3 patients. The mean time to follow-up was 5.1 years. In a matched-pair-analysis this group was compared to a group of young patients with a mean age of 43 years (26-56) and identical lesions and surgical procedures. The mean time to follow-up in this group was 4.2 years. We observed that fractures at higher age resulted mostly from trivial accidents. Except from a prolonged inpatient time the initial course was comparable. In a 66 year-old woman early implant removal was necessary because of infection. Despite identical surgical treatment we observed a loss of reduction with incongruency of the plateau and deviation of the axis. Correspondingly older patients displayed a statistically significant threefold increase of osteoarthritis compared to younger patients. However, there was no clinical correlation using the Rasmussen, OAK and Lysholm score. Both groups displayed no statistical significant differences for the parameters function, stability and pain. According to the old age the only significant difference was a reduction of the Tegner score. Reduction and internal fixation of tibial plateau fractures in an elderly population displayed mostly a satisfactory clinical result within this 5-year period. The problem of loss of reduction and rapid osteoarthritis remains to be evaluated in a larger group over a longer period of time.

Helicobacter pylori-induced hyperproliferation: relevance for gastric cancer development in connection with mutagenic factors

AIMS

Current data on Helicobacter pylori induced regenerative hyperproliferation of the antral gastric mucosa and significance in cancer development are still under discussion and investigation. An improved method for evaluation of the regeneratory process in antral mucosa is introduced and compared with the conventional method used for determination of proliferating cells in perpendicular sections of the gastric mucosa.

METHODS

Using a combination of immunohistochemistry and PAS-staining the expression of Ki-67 (MiB1)-proliferation associated antigen was analyzed in 50 Helicobacter pylori (Hp) positive and 35 negative biopsies of the gastric antrum. PAS-staining was performed to identify the proliferative zone of the antral gastric glands. The degree of inflammation was evaluated by grades on routinely H & E-stained slides.

RESULTS

Proliferative activity is significantly increased in Hp-positive cases (p = 0.00095) compared to negative ones. By using the conventionally applied proliferation index, every nucleus has to be counted and the proliferation zone is identified by at least one positive stained nucleus. The method presented here seems to be easier because the proliferative zone is clearly identified by PAS staining of neutral glycoproteins characteristic for the proliferation zone of antral glands. The density of labeled nuclei is determined and is expressed as a proliferation factor. This factor gives more distinct values, is easier to evaluate and shows a better correlation with the helicobacter status and the degree of inflammation. These results are discussed in relation to the data from the literature and with a view to other relevant factors in the course of carcinogenesis, such as growth factors, mainly EGF, p53 mutation and role of apoptosis, genetic instability and local production of oxidants.

CONCLUSION

Helicobacter pylori induces an increase of regenerative proliferation activity. Under these conditions the chance of mutation is increased and time for DNA repair reduced. This could be at least a part of multiple step carcinogenesis. The newly introduced combination of staining procedures (PAS/MiBI) allows a more differentiated evaluation of the proliferation zone and its widening. This method can be more easily handled in follow-up studies than the method using perpendicular sections because in this method heavy irregularities of gland pattern induced by accompanying inflammatory processes considerably hinder evaluation.

Cystosarcoma phyllodes of the breast: prognostic significance of proliferation and apoptosis associated genes

BACKGROUND

Cystosarcoma phyllodes (CP) is a rare fibroepithelial tumor of the breast. So far no valuable prognostic factors are available for predicting the biological behaviour and often unexpected clinical outcome of this tumor.

PATIENTS AND METHODS

Using immuno-histochemistry, Mib-1 evaluated proliferative activity and expression of p53, Bcl-2, c-erbB1, c-erbB2, cytokeratin and vimentin were analysed in 17 benign and 12 malignant CP.

RESULTS

Cell proliferation was significantly higher in malignant tumors compared to benign ones both in the epithelial and mesenchymal parts. In the epithelial part Bcl-2 positive cells were found more frequently in benign than in malignant lesions. Positive immunoreactivity for p53 was seen in only one malignant case. The reaction was positive in the both epithelial and mesenchymal compartments. Expression of c-erbB-proteins was not found in any case. The intermediate filament proteins indicate clearly the two components of the tumor.

CONCLUSIONS

We concluded that increased proliferate activity and downregulation of Bcl-2 may be associated with dedifferentiation of cells and malignant progression. C-erbB-proteins are obviously not involved in carcinogenesis of CP.