Klatskin tumour: meticulous preoperative work-up and resection rate.

BACKGROUND: Surgery represents the only potentially curative treatment of hilar cholangiocarcinoma (hilCC). It may be suggested that meticulous preoperative work-up in Asian countries leads to higher resection rates. METHOD: One hundred and eighty-two patients treated in our department between 1998 and 2008 were included in an analysis based on our prospectively recorded database. Among them, 75 % had a percutaneous transhepatic cholangiography as part of their diagnostic work-up. A total of 160 patients underwent explorative surgery and 123 patients were resected (77 % of patients undergoing exploration, 68 % of all patients). RESULTS: Ninety-one percent of the patients were diagnosed to have Bismuth III and IV tumours. En-bloc resection of the tumour and the adjacent liver including segment 1 was the standard procedure in 109 of these patients, while hilar resection was performed in 14 patients. Upon tumour resection, hospital mortality was 5.7 %. Five-year survival in patients without surgery or with mere exploration was 0 %, after resection it reached 26 %. Patients with R 1 resection experienced longer survival than patients without resection (p < 0.001). Right and left hemihepatectomies were performed with identical frequency resulting in identical survival. Lymph node involvement proved to be the only significant predictor of prognosis (p = 0.006). CONCLUSION: Resection should be performed whenever possible since even after palliative resection survival is substantially increased compared to patients without resection. Meticulous preoperative work-up may contribute to a high resection rate in patients with hilCC by providing additional information allowing the surgeon to perform more aggressive approaches.

Expression of E-selectin and vascular cell adhesion molecule-1 in so-called 'negative' appendices: first results to support the pathological diagnosis in borderline cases.

BACKGROUND: Since the rate of histologically 'negative' appendices still ranges between 15 and 20%, appendicitis in 'borderline' cases remains a challenging disease. As previously described, cell adhesion molecule expression correlates with different stages of appendicitis. Therefore, it was of interest to determine whether the 'negative' appendix correlated with the absence of E-selectin or vascular cell adhesion molecule-1 (VCAM-1). METHODS: Nineteen grossly normal appendices from a series of 120 appendectomy specimens from patients with suspected appendicitis were analysed in frozen sections for the expression of E-selectin and VCAM-1. As control, 5 normal appendices were stained. RESULTS: This study showed a coexpression of E-selectin and VCAM-1 in endothelial cells in early and recurrent appendicitis. In patients with symptoms for less than 6 h, only E-selectin was detected. Cases with fibrosis and luminal obliteration were only positive for VCAM-1. In cases of early appendicitis with symptoms of less than 6 h duration, a discordance between histological and immunohistochemical results was found. CONCLUSIONS: This report indicates that E-selectin and VCAM-1 expression could be useful parameters in the diagnosis of appendicitis in borderline cases.

[Mast cell-rich aluminium granuloma]. / Mastzellreiches Aluminiumgranulom.

Persistent subcutaneous nodules arise at the injection sites of aluminium hydroxide-absorbed hyposensitization solutions. We present a hitherto unreported phenomenon in aluminium granuloma. Two years after specific immunotherapy, a patient suffered increasingly from urticaria. Besides inflammatory infiltrates surrounding necrotic areas, microscopy of the specimen revealed numerous mast cells surrounding the necrotic tissue areas. The histological phenomenon of increased mast cell populations in aluminium granuloma might reflect the association with urticaria, which is probably more frequent than previously reported.

Methylene blue-aided cholangioscopy in patients with biliary strictures: feasibility and outcome analysis.

BACKGROUND AND STUDY AIMS: Chromoendoscopy using methylene blue is employed in the gastrointestinal tract to delineate neoplastic lesions. We tested the value of chromoendoscopy during choledochoscopy for characterization of local inflammation, neoplasias, and other alterations in patients with biliary strictures. METHODS: Patients with suspected biliary lesions were scheduled for endoscopic retrograde cholangiography with subsequent cholangioscopy. After initial inspection of the bile duct, 15 ml methylene blue (0.1 %) was administered via the working channel of the cholangioscope. Newly appearing circumscribed or unstained lesions were judged according to their macroscopic type and staining features. Methylene-blue-aided diagnosis was compared with either clinical follow-up of the patients or, in some cases, with the results of targeted biopsies. RESULTS: A total of 55 patients [biliary stenosis/cholestasis of unknown origin (n = 24), stenosis after orthotopic liver transplantation (n = 11), primary sclerosing cholangitis (n = 20)] were included. Methylene blue unmasked subtle mucosal changes and permitted macroscopic characterization of circumscribed lesions. Characteristic surface staining patterns were seen in chronic inflammation, dysplasia, and ischemic-type biliary lesions. Nondysplastic mucosa appeared homogeneously stained, whereas scarred strictures showed a weak uptake of methylene blue. CONCLUSION: In this prospective feasibility study, methylene-blue-aided cholangioscopy was used for the first time to define different staining patterns of the bile duct. The differences in staining patterns identified normal, dysplastic, and inflamed mucosa of the bile duct, as was proved by follow-up or, in some cases, histology. Whereas homogeneous staining predicted the presence of normal mucosa, absence of staining of circumscribed lesions, or diffused staining of such lesions, represented neoplastic changes or inflammation.

Malignant and unclear histological findings in incidentalomas.

BACKGROUND: The management of incidentalomas with tumor size 3 cm and larger is still under controversial discussion. STUDY DESIGN: Clinical charts of 65 patients who underwent adrenalectomy for an incidentaloma were reviewed. RESULTS: Sixty-five patients were operated. There were 28 men and 37 women with a median age of 56.9 years. Median size of all resected lesions was 4.1 cm. Indications for surgery were tumor size equal and larger than 3 cm, recurrent pain, hormone status and patients' fear of malignancy. In 45 patients, the adenomas did not meet the defined criteria of malignancy. There were 9 cases of adrenal hyperplasia, and two cysts and two hematomas were found in 4 patients. Moreover, 1 schwannoma and 1 myelolipoma were removed. In 3 patients, a primary adrenocortical carcinoma of 3.4, 4.0, and 5.0 cm in diameter, respectively, was identified. In 1 patient, an adrenal cortical carcinoma of 10.0 cm in diameter was operated. In 1 patient, the status (size: 4.5 cm) could not be determined conclusively. CONCLUSION: Hormonal activity should be determined independent of the size, and lesions with hormonal activity should be resected; in the presence of hormonally inactive masses, removal of tumors of 3 cm and larger in size is recommended.

Intraoperative assessment of liver organ condition by the procurement surgeon.

UNLABELLED: Generally the transplanting surgeon accepts or declines the offer of a marginal organ in view of all available information. Hence, in some cases it is the procurement surgeon who decides about the suitability for potential further liver transplantation. METHODS: From January 1, 2003 to September 30, 2005, a total of 402 organ procurement operations were performed in our region. RESULTS: Due to infrastructural problems in nine cases intraoperative evaluation of liver biopsies was not achievable in time, and the decision to reject the organs was based on the procurement surgeon's clinical assessment. The main reason for liver rejection was alleged extreme steatosis, (6 of 9) or liver cirrhosis (3 of 9). Surprisingly, postoperative histological examinations only confirmed the clinical impression in one of nine cases. CONCLUSIONS: The clinical assessment of the explanting surgeon resulted in discarding eight of nine organs, potentially not contributing them to the donor pool of EUROTRANSPLANT. Further research is necessary to examine the accuracy of clinical evaluation of donor livers as well their correlation with histology.

Tacrolimus monotherapy without steroids after liver transplantation--a prospective randomized double-blinded placebo-controlled trial.

Early steroid withdrawal after liver transplantation (LT) is desirable in order to reduce steroid side effects. Between February 2000 and August 2004, 110 patients after LT were included in this prospective, randomized, double-blind, placebo-controlled trial. Randomization was performed before LT. In all patients, tacrolimus was used without induction therapy. All patients received methylprednisolon for 14 days, thereafter a double-blinded medication containing either placebo (n = 56) or methylprednisolon (n = 54) for 6 months, which was completely stopped thereafter. End points were patient and graft survival, acute and chronic rejection, and incidence of steroid side effects during the first year after LT. One-year patient survival was 85.7% (placebo) and 88.8% (steroid) (p = 0.572). Twenty-seven (48.2%) and 19 (35.2%) patients experienced acute rejection (placebo versus steroid, respectively; p = 0.116). Two patients in the placebo group but none in the steroid group experienced chronic rejection (p = 0.257). The rates of side effects were (placebo versus steroid, respectively): CMV infection 25% versus 33% (p = 0.336), post-transplant diabetes 30% versus 53% (p = 0.024), hypertension 39% versus 52% (p = 0.248), hypercholesterolemia 10% versus 41% (p = 0.002) and hypertriglyceridemia 32% versus 54% (p = 0.046). In conclusion, early steroid withdrawal after LT is feasible under tacrolimus monotherapy without increased rejection rates and with a lower rate of side effects.

Transarterial chemoembolization before liver transplantation in 60 patients with hepatocellular carcinoma.

Tumor recurrence is a major problem after orthotopic liver transplantation (OLT) in patients with hepatocellular carcinoma (HCC). In 60 patients OLT was performed for HCC after pretreatment by repeated transarterial chemoembolization (TACE). Forty-four recipients exceeded the Milan criteria. Recurrence-free 5-year survival was 65.2% and 5-year freedom from recurrence was 73.2%. During the waiting time, 14 patients experienced minimal change, which did not fulfill the definition of tumor progression according to official oncological criteria. Five-year freedom from recurrence among patients with stable compared with progressive disease was 93.3% versus 28.1%, respectively (P = .0001). A strict TACE pretreatment protocol may select patients with obviously biologically less aggressive tumors, who are suitable for OLT even if the HCC exceeds the commonly accepted listing criteria.

[Massive hemorrhage in a 28-year-old male patient with intestinal Behçet's disease]. / Massive gastrointestinale Blutung eines 28-jährigen Patienten mit intestinalem Befall eines Morbus Behçet.

A 28-year-old man was admitted to the emergency room of our hospital after syncope and acute gastrointestinal bleeding. On the basis of numerous oral and genital ulcerations as well as uveitis anterior and erythema nodosum, the diagnosis of Behçet's disease had been confirmed previously. The bleeding focus could not be detected by endoscopy. During the next days recurrent massive hemorrhages occurred in spite of immunosuppressive therapy with steroids. Angiography revealed a circumscribed bleeding source in the colon transversum near the left colonic flexure, which was treated by superselective coil embolization. A massive hemorrhage reoccurred and required a surgical approach with a Hartmann procedure. Histology depicted bleeding into the submucosa and mucosa and an ulcer in this area as well as lymphatic infiltration of the mucosa. Immunosuppressive therapy was intensified with azathioprine and resulted in a dramatic improvement of the oral and genital ulcers. In addition, no further gastrointestinal hemorrhage occurred. Due to its higher prevalence in patients from eastern Asia, Behçet's disease poses an important differential diagnosis of intestinal hemorrhage in patients of this descent.

Image cytometric DNA analysis of mucosal biopsies in patients with primary achalasia.

AIM: To determine DNA aneuploidy in mucosal biopsies of achalasia patients for subsequent rapid diagnosis. METHODS: Biopsies from the middle third of the esophagus were obtained in 15 patients with achalasia. Immunohistochemical staining was carried out with monoclonal antibodies MIB-1 for Ki67 and PAb 1801 for p53, in addition to the conventional histologic examination for dysplasia. Nuclei of fresh biopsy material were enzymatically and mechanically isolated, and the DNA content was determined with image cytometry after Feulgen staining. DNA grading of malignancy was assessed according to Boecking to determine the variability of DNA values noted around the normal diploid peak. Further indices measured included the aneuploid rate, and the 5c-, 7c- and 9c-exceeding rate. RESULTS: The histological examination did not demonstrate dysplasia; while MIB-1 (basal) showed a positive reaction in 8/15 achalasia specimens, p53 was negative in all specimens. Image cytometric DNA analysis detected aneuploidy in 4/15 (26.7%) specimens. Samples from 15 patients with squamous cell carcinoma as well as specimens obtained exclusively 2 cm proximal to the tumor served as reference tests. All carcinomas (15/15) as well as 9 of the peritumoral samples (9/15) were aneuploid. The comparison of biopsies from achalasia patients with peritumoral and carcinoma specimens revealed statistically significant differences regarding the aneuploid rate (diploid: P < 0.0001; tetraploid: P = 0.001), grading of malignancy according to Boecking (P < 0.0001) and the 5c- (P < 0.0001), 7c- (P < 0.0001), and 9c- (P = 0.0001) exceeding rate with progredient DNA alterations in the respective order. CONCLUSION: The finding that DNA aneuploidy was identified by image cytometry in esophageal specimens of patients with achalasia, which may be due to specific chromosomal alterations presenting as precancerous lesions in 27% of patients, leads us to conclude that image cytometry represents a valuable screening tool.

[Second reading of breast imaging at the hospital department of radiology: reasonable or waste of money?]. / Mammadiagnostische Zweitbefundung in der Radiologischen Klinik: sinnvoller Mehraufwand oder Ressourcenverschwendung?

PURPOSE: To assess the effect of a second diagnostic reading of breast imaging at a university department of radiology. MATERIAL AND METHODS: The diagnostic reports of first readers from different private radiology practices and the reports of second readers from the university department of radiology were compared with the histological results (n = 214) and outcome of follow-ups for 4 years (n = 74) in 236 patients (mean age 55 years). BI-RADS categories were used for this purpose. The initial examinations had been performed because of symptoms (n = 117), early detection outside an organized screening program (n = 102), evaluations following breast cancer therapy (n = 13) and unknown primary tumors (n = 4). In addition, the number of complementary examinations and the influence of a second reading on patient management were evaluated. RESULTS: A total of 140 lesions were malignant and 148 were benign. Of the 288 lesions, 49 % were classified identically in the second reading; 36 % (79/217) of the lesions initially classified as BI-RADS 4 and 5 were downgraded to benign; and 41 % (29/71) of the lesions classified as BI-RADS 1 to 3 were upgraded as suspected of being malignant. The kappa value between the first and second readers was 0.34 with respect to each BI-RADS category separately and 0.18 with respect to categories 1 to 3 (benign) versus 4 and 5 (malignant). A second reading increased the sensitivity from 81 % (114/140) to 96 % (135/140) and the specificity from 30 % (45/148) to 78 % (116/148). Second readers detected 23 additional malignant lesions, changed two lesions correctly classified as malignant to benign categories and caused 6 additional false-positive findings. In all, 38 surgical biopsies could be prevented, one biopsy was erroneously delayed and three unnecessary excisional biopsies were initiated. In the study group, 49 MRI examinations revealed 5 additional malignant lesions and positively influenced surgical planning in 28 patients. In addition to these MRI examinations, 221 patients were examined using ultrasonography, 62 patients using complementary mammography, and 7 using galactography. CONCLUSION: The benefit of a second reading outweighs the expenditure.

Complete gangrene of penis in patient with arterial vascular disease.

We present a clinical case of distal penile gangrene in a patient with peripheral vaso-occlusive disease that did not correlate with the extension of the intraoperative finding and required total penectomy. Surgical intervention at the onset of wet gangrene avoids the complication of sepsis.

[Diagnostic imaging of hilar cholangiocarcinoma: preoperative evaluation of ERC, MRC and PTC in comparison with histopathology]. / Die Diagnostik des hilären Cholangiokarzinoms: Wertigkeit von präoperativer ERC, MRC und PTC im Vergleich zur Histopathologie.

PURPOSE: To compare the results of the preoperative workup consisting of endoscopic retrograde cholangiography (ERC), magnetic resonance cholangiography (MRC), and percutaneous resonance cholangiography (PTC) with the tumor extent of the surgical specimen in patients with hilar cholangiocarcinoma (hilCC). MATERIALS AND METHODS: Between 9/1997 and 12/2002, 59 patients with hilCC tumor underwent surgical resection. Preoperative ERC, MRC, and PTC were analyzed, blinded for the identity of the patient, and compared with the surgical specimen. For this retrospective analysis, 55 of the initial 59 ERCs, 39 of the initial 40 MRCs and 32 of the initial 38 PTCs were available. Most of the ERCs and MRCs had been performed at referring institutions by various investigators. In 20 patients, all three imaging modalities were available for direct comparison. RESULTS: The mean scores of the visualization of the bile ducts and tumor differ considerably for ERC, MRC and PTC, with PTC visualizing the bile ducts better than ERC (p < 0.001) and MRC (p = 0.019). The tumor classification according to Bismuth and Corlette was correctly predicted by ERC in 29 %, by MRC in 36 % and by PTC in 53 %. The tumor extent was overestimated in 40 % (ERC), 41 % (MRC) and 31 % (PTC) and underestimated in less than 10 % for all modalities. Twenty patients, who underwent all three imaging modalities, were included in an additional analysis for a direct comparison of ERC, MRC and PTC. PTC provided correct or acceptable information on tumor extent in 19 of 20 patients, MRC in 15 of 20 patients, and ERC in only 11 of 20 patients. The statistical analysis revealed a significant superiority of PTC to ERC (McNemar test: p < 0.01) but not to MRC (p = 0.22). DISCUSSION: The management of patients with hilar cholangiocarcinoma requires a high degree of expertise in diagnostic imaging techniques. Cholangiography should not only define the location but also visualize the uppermost extent of the tumor to determine resectability. In contrast to most reports in the literature, ERC and MRC were found to be of limited reliability regarding the assessment of the tumor extent. ERC may be more and more reserved for patients considered for nonsurgical intervention or palliation. PTC proved to be the most reliable approach. MRC represents a noninvasive diagnostic tool for the evaluation of malignant perihilar biliary obstructions, but should be performed at highest quality using state-of-the-art MRI techniques. The most common mistake of each diagnostic modality was an overestimated tumor extent, which may exclude patients from potentially curative surgery.

Preoperative imaging of hilar cholangiocarcinoma: surgical evaluation of standard practises.

UNLABELLED: It was the goal of this study to compare the results of the preoperative diagnostic workup (ERC, MRC, and PTC) with the tumor extent of the surgical specimen in patients with hilar cholangiocarcinoma (hilCC). PATIENTS AND METHODS: Between 9/97 and 12/2002 82 patients with hilCC were treated at our institution. In 59 patients tumor resection was feasible. Preoperative ERC, MRC and PTC - blinded for the idendity of the patients - were analysed retrospectively and compared with the surgical specimen. RESULTS: PTC resulted in significantly superior visualization of the bile ducts including the hilar lesion compared to ERC and MRC (p < 0.01). ERC, MRC and PTC were correct in predicting tumor extent in 29, 36 and 53 % of cases, respectively. The extent of the tumor was overestimated in 42 % (ERC), 41 % (MRC) and 31 % (PTC). Underestimation or wrong assessment or no decision at all occurred in 31, 23 and 16 %, respectively. In 20 patients results of all three diagnostic methods were available allowing a statistical comparison regarding the resection to be performed: PTC was superior to ERC (McNemar test:p < 0.01), but not to MRC. In the patients with overestimated tumor extent both the rate of curative resections and survival were similar to the other resected patients. DISCUSSION: In contrast to most reports in the literature, ERC and MRC were found to be of limited reliability regarding the assessment of tumor extent. PTC proved to be the most reliable approach. Overestimation of the tumor extent, which may lead to exclude the patient from potentially curative surgery, was the most common mistake in each diagnostic modality.

[Hilar cholangiocarcinoma -- results of en bloc resection of tumor and liver]. / Hiläres CholangiokarzinomErgebnisse bei En-bloc-Resektion von Tumor und Leber.

The increasingly performed en bloc resection of liver and hilar tumor has contributed to the improvement of long-term survival in patients with hilar cholangiocarcinoma. Based on preoperative definition of operative strategy we tried to avoid any traumatization of the hilar region. Between September 1997 and September 2002, 82 patients with hilar cholangiocarcinoma were treated at our department. Three patients were excluded from any surgery. The resection rate was 75% (59 of 79); 79% (38 of 48) of en bloc resections of the hilar tumor and adjacent liver were formally curative. The hospital mortality was 7%. The 1- and 3-year survival rates of patients after explorative laparotomy, palliative and curative resection was 27 and 7%, 67 and 26%, 89 and 45% ( p<0.001), respectively. The 1- and 3-year survival rates of patients after en bloc resection were 78 and 49%, respectively. In patients with formally curative en bloc resection ( n=38), the 3-year survival rate was 63%; in patients with N0/R0 resection ( n=31) it was 71%. Lymph node involvement proved to be the only independent prognostic marker if patients who underwent hilar and en bloc resection were included in the multivariate analysis. The R situation was the only significant predictor for patients after en bloc resection. These data justify the extended diagnostic work-up and the principal liver resection in hilar cholangiocarcinoma.

Expression of KIT (CD117) in biphasic pulmonary blastoma. Novel data on histogenesis.

Biphasic pulmonary blastoma (BPB) is a rare primary neoplasm of the lung and its histogenesis is still uncertain. It has been proposed that BPB is derived from mesoderm or endoderm. Others suggested an origin from a single pluripotential cell. We present a case of a BPB with emphasis on expression of the stem cell factor receptor KIT (CD117). We describe a 61-year-old male patient with a BPB of the upper right lobe. Immunohistochemical analysis was performed using a panel of several antibodies including anti-CD117. Strong cytoplasmic expression of CD117 was found in the epithelium (cytokeratin-positive) as well as in the spindle cells (cytokeratin-negative). Expression of CD117 in both mesenchymal and epithelial cells suggests a single origin and supports the idea that BPB arises from a pluripotential cell that can differentiate into both stromal and epithelial morphologies. The role of CD117 in the pathogenesis of BPB and its possible therapeutic relevance require further investigation.

[Endosonographically controlled transluminal fine needle aspiration biopsy: diagnostic quality by cytologic and histopathologic classification]. / Endosonographisch gesteuerte transluminale Feinnadelpunktion: Untersuchung zur diagnostischen Qualität.

BACKGROUND AND OBJECTIVE: EUS-guided fine needle aspiration (EUS-FNA) has emerged as a highly accurate technique for detecting and classifying mediastinal and pancreatic lesions as well as abdominal and recently retroperitoneal masses with a minimum of risk for the patient. PATIENTS AND METHODS: To objectify these statements, we evaluated the quality of 72 EUS-FNA specimens by cytologic and histopathologic classification, investigated their contamination with tissue from the needle pathway and observed puncture-related complications in a retrospective study of 44 EUS-FNA in 41 consecutive patients (56 +/- 14 years, m = 24, f = 17; 13 pancreatic, 9 adrenal, 6 abdominal and 13 mediastinal masses). EUS-FNA was performed using a PENTAX 32 UA endosonoscope (longitudinal 7.5 MHz sector array) in combination with a needle system type "Hancke-Vilmann". RESULTS: 16 vs. 11 of 34 histopathologic and 38 cytologic specimens were classified "excellent", 7 vs. 10 "sufficient", 7 vs. 13 "poor" and 4 vs. 4 "failed". Analysis of contamination with tissue from the needle pathway showed 4 vs. 2 specimens "highly", 3 vs. 14 "clearly", 8 vs. 19 "slightly" and 19 vs. 3 "not" contaminated. Specimens classified "excellent" were less contaminated (p = 0,037). EUS-FNA identified 35 benign and 24 malignant masses. Definite diagnosis failed in 13 specimens. One nonfatal complication occurred. EUS-FNA is an accurate (89 %) and low-risk procedure to examine primary undiagnosed mediastinal, pancreatic, intraabdominal and especially adrenal lesions in most of the cases. Contamination with tissue from the needle pathway seems to be a major predictive factor of poor specimen quality and failed diagnosis. CONCLUSION: EUS-FNA expands the diagnostic approach of mediastinal, abdominal, pancreatic and adrenal masses and provides accurate specimens for reaching new differential-diagnostic competence, especially in endocrinologic cases.

Chromosomal aberrations in premalignant and malignant squamous epithelium.

Biopsies of oropharyngeal cancer were screened for chromosomal imbalances by comparative genomic hybridization (CGH) performed on 22 primary tumors and morphologically nonmalignant surrounding mucosa. The aim was to determine early chromosomal changes of tumor development and to draw conclusions on the mechanisms leading to multiple tumors. The most prominent chromosomal imbalances observed were over representations of genomic material on 3q, 15q, 8q, and 11q and losses on 9p, 3p, and 11q. In morphologically normal mucosa collected at 1 cm from the primary tumor border (M1), amplifications on 15q and 21q were most frequent. Far fewer gains and losses were found in M1 than in the primary tumor (average 2.2 vs. 6.9). Gains dominated over losses, but a tendency toward an increasing proportion of losses in the primary tumor (PT) was observed (ratio of gains to losses: PT, 4.75; M1, 6.3). Almost all the imbalances in M1 were detected in the primary tumor. No chromosomal alterations were identified with CGH in tissue samples dissected at 2 cm from the primary tumor (M2). In all samples, dysplastic morphologic changes decreased with distance from the primary tumor, which correlates with the observed lower level of genetic changes. We suggest that gains of genetic material on 15q and 21q are early events in malignant progression of squamous cell carcinoma, followed by gains on 3q, 8q, and 11q, and losses on 3p and 9p at later stages. Based on our cytogenetic data, we discuss the monoclonal model followed by lateral epithelial spread as an explanation of multiple head and neck squamous cell carcinomas.

Tissue response and biomaterial integration: the efficacy of in vitro methods.

Implantation involves tissue trauma, which evokes an inflammatory response, coupled to a wound healing reaction, involving angiogenesis, fibroblast activation and matrix remodelling. Until now the type and extent of such reactions to give optimal integration of various biomaterials are practically unknown. Three principal fields of research can yield useful data to understand these phenomena better: studies on explanted biomaterials, animal models and relevant in vitro techniques. This paper will present examples of the latter field and the application of endothelial cell (EC) culture systems to study the effects of important tissue (e.g. pro-inflammatory cytokines, chemokines) and material (e.g. metal ions, particulate debris) factors on the regulation of the inflammatory and angiogenic response. A central feature is the use of microvascular endothelial cells (MEC), which can be used in both 2-and 3-dimensional (3-D) assays. We have also used genetic manipulation to develop a permanent MEC line from the human lung (HPMEC-ST1), which is being tested for its suitability to study cell-biomaterial interactions. In addition, suitable in vitro techniques are being developed in order to investigate drug delivery systems (DDS). Of particular interest is the targeting of the central nervous system, our approach being to establish a human model of the blood-brain barrier (BBB). A mainstay of our scientific philosophy is that such in vitro methods can make an important contribution to understanding biological reactions at the tissue-biomaterial interface and thus further a causal approach to tissue engineering (TE) and drug delivery applications.