Integrated FDG PET-CT imaging improves staging in malignant pleural mesothelioma

AIM of this study was to investigate, how often TNM staging is changed in patients with malignant pleural mesothelioma (MPM) by the application of integrated PET-CT compared to computed tomography alone and how often these changes are clinically relevant.

PATIENTS, METHODS

We studied 17 patients (68 +/- 6 years, 8 women) with MPM. Integrated PET-CT scan and histological confirmation were performed in all patients.

RESULTS

Final histological diagnosis confirmed 9 epithelial type, 2 sarcomatoid type and 6 biphasic type MPM. Mean standardized uptake value (SUV) was 5.9 +/- 1.9 in epithelial MPM and 15.1 +/- 10.2 in sarcomatoid MPM. CT and PET-CT revealed discordances in 8/17 (47%) patients in TNM classification with 4/8 (50%) being clinically relevant. PET-CT led to downstaging in 5 (29%) and upstaging in 3 (18%) patients. Mean survival time tended to be higher in the subgroup of patients with lower mean SUV.

CONCLUSIONS

PET-CT seems to be a valuable tool in staging of MPM and leads to discordant findings in almost every second patient compared to CT alone. In many cases these differences are clinically relevant and have therapeutic consequences.

[Localized amyloidosis of the ureter]

Localized amyloidosis of the ureter is a rare condition. Because of the difficulty in differentiating between localized amyloidosis and an obstruction due to other benign or malignant conditions of the urinary tract, in some cases even an unnecessary nephroureterectomy is performed. We describe a patient with obstructive amyloidosis of the right ureter. Diagnosis was confirmed by endoscopy with biopsies. The patient was treated successfully by partial ureterectomy and ureteroneocystostomy. No systemic involvement of other organs was detected and after a 2-year follow-up no local recurrence developed.

Atypical bronchial thickening and ulceration: a rare radiological finding in Wegener's granulomatosis

We report the case of a 55-year-old male patient who presented with non-specific pulmonary symptoms (cough, haemoptysis, fever up to 39 degrees C, night sweats and weight loss). After empirical antibiotic therapy prescribed by his primary care physician, the patient showed no improvement in symptoms. Laboratory findings were: elevated C-reactive protein and C-ANCA, leukocytosis and thrombocytosis, and anaemia. Chest radiography showed disseminated nodules bilaterally. On multidetector-row computed tomography (MDCT), the bronchial walls showed a significant thickening and extensive peribronchiolar consolidations. Bronchoscopy revealed diffuse erythema of the tracheobronchial mucosa with diffusely scattered white plaques. Histopathology described a multifocal ulcerative bronchitis with underlying chronic bronchitis. These findings in combination with the laboratory data lead to the diagnosis of Wegener's granulomatosis. Consequently, we started with an immunosuppressive therapy. Chest radiography after 10 days showed marked resolution of the infiltrates. Within 1 month, the patient became asymptomatic.

Computer-assisted placement technique in hip resurfacing arthroplasty: improvement in accuracy?

Freehand positioning of the femoral drill guide is difficult during hip resurfacing and the surgeon is often unsure of the implant position achieved peroperatively. The purpose of this study was to find out whether, by using a navigation system, acetabular and femoral component positioning could be made easier and more precise. Eighteen patients operated on by the same surgeon were matched by sex, age, BMI, diagnosis and ASA score (nine patients with computer assistance, nine with the regular ancillary). Pre-operative planning was done on standard AP and axial radiographs with CT scan views for the computer-assisted operations. The final position of implants was evaluated by the same radiographs for all patients. The follow-up was at least 1 year. No difference between both groups in terms of femoral component position was observed (p > 0.05). There was also no difference in femoral notching. A trend for a better cup position was observed for the navigated hips, especially for cup anteversion. There was no additional operating time for the navigated hips. Hip navigation for resurfacing surgery may allow improved visualisation and hip implant positioning, but its advantage probably will be more obvious with mini-incisions than with regular incision surgery.

[Mixed episodes in bipolar disorder: a review]

Affective mixed states in bipolar disorders are a current matter of scientific debate and represent a complex clinical picture with coexisting manic and depressive symptoms. Treatment of mixed states is regarded as an important challenge. As diagnostic uncertainties complicate systematic clinical evaluations of this patient group, generally accepted clinical treatment guidelines are lacking yet. In this review the significance as well as the problems and risks of new treatment options are discussed.

[Bipolar disorders: the disease of extreme emotions]

Bipolar disorder is characterized by alternating phases of manic and depressive states that are separated by variably long and sometimes symptom-free intervals. Rapid changes in symptoms and mixed states during acute episodes can make diagnosis difficult. The risk of suicide is high. For diagnostic confirmation, the patient should be referred to a specialist as early as possible. The therapy should also be carried out in close collaboration with a neurologist or psychiatrist. The role of the family physician is to monitor the pharmaceutical phase prophylaxis and to attend to the patient's comorbidities.

Relevant imaging findings of cerebral aspergillosis on MRI: a retrospective case-based study in immunocompromised patients

The aim of the study was to assess neuroimaging patterns of cerebral aspergillosis with magnetic resonance imaging (1.5 T). The clinical and imaging data of nine patients were reviewed. Patients were included in the study if the diagnosis of aspergillosis was confirmed by either biopsy, autopsy, aspergillus antigen determination and/or neuroradiological and clinical response to specific treatment. Four patients had single or multiple abscesses presenting as ring-enhancing lesions on T1-weighted images, hypointensity of the ring on T2-weighted MR images and low to high signal intensity on diffusion-weighted imaging. Four patients had single or multiple infarctions affecting all compartments of the brain with hyperintensities on T2-weighted images in three of four patients, irregular parenchymal contrast enhancement in all patients and hemorrhagic transformation of the infarcted parenchyma in one patient. Diffusion-weighted images were positive in all ischemic areas. One patient with paranasal sinusitis developed a mycotic aneurysm of the internal carotid artery. Cerebral aspergillosis presents three principal neuroimaging findings: areas consistent with infarction; ring lesions consistent with abscess formation following infarction; and dural or vascular infiltration originating from paranasal sinusitis or orbital infiltration. Recognition of these patterns in cerebral aspergillosis may lead to more timely and effective diagnosis and treatment.

VEGF(165) and bFGF protein-based therapy in a slow release system to improve angiogenesis in a bioartificial dermal substitute in vitro and in vivo

BACKGROUND

Angiogenesis can be enhanced by several growth factors, like vascular endothelial growth factor-165 (VEGF(165)) and basic fibroblast growth factor (bFGF). Delayed release of such growth factors could be provided by incorporation of growth factors in fibrin matrices. In this study, we present a slow release system for VEGF(165) and bFGF in fibrin sealant.

MATERIALS AND METHODS

In vitro: Pieces of Integratrade mark matrix of 15 mm in diameter were prepared. Integratrade mark matrices were divided into four groups (A=control; B=fibrin sealant; C=fibrin sealant+growth factors; D=growth factors). In vivo: The bioartificial dermal templates were transplanted into a full-skin defect of the back of nu-nu mice. Four different groups included each six matrices at 2 and 4 weeks.

RESULTS

In vitro: In groups C and D, continuous release of VEGF(165) and bFGF was eminent. The incorporation of growth factors into fibrin sealant evoked a prolonged growth factor release (p < 0.05). In vivo: A significantly higher amount of vessels was quantified in groups C and D compared to groups A and B (p < 0.001).

CONCLUSIONS

A model of slow protein release by combining VEGF(165) and bFGF with fibrin sealant was produced. This model resulted in a prolonged bioavailability of growth factors in vivo for functional purposes. Fibrin and collagen can release growth factors in vivo and induce significant and faster neovascularisation in bioartificial dermal templates.

[Clinical standing of valproate treatment of bipolar disorders]

During recent years valproate has been established as a cornerstone for the drug-treatment of bipolar disorder. In Germany, valproate was licensed both for the treatment of acute mania and for maintenance treatment in summer 2005. At this occasion, this review summarises the scientific evidence and clinical experience of well-known experts with valproate-treatment. It was concluded that valproate will continue to be of high clinical significance despite the recent increase of treatment alternatives, both in monotherapy and combination treatment of acute mania, mixed states and maintenance treatment.

Prognostic significance of clusterin immunoreactivity in breast cancer

Clusterin (CLU) is involved in a variety of biological processes and has been found to be expressed even in many human malignancies, including breast cancer. Currently, there are only few data on the prognostic value of CLU in breast cancer. We therefore evaluated the relationship between CLU expression and clinicopathological parameters as well as relapse-free survival (RFS) and metastasis-free survival (MFS) of 141 breast cancer patients using the monoclonal antibody 7D1. CLU expression was found in 26% of cases and correlated significantly with high histological tumor grade and high Ki-67 labeling index (p=0.026 and p=0.010, respectively). Univariate Cox regression analysis revealed that CLU expression was tendentiously associated with RFS (p=0.068; relative risk [RR]: 1.77) and MFS (p=0.122; RR: 1.57). In a multivariate analysis, tumor grade, stage, estrogen receptor status and patients age (concerning RFS) as well as grade and lymph node status (concerning MFS) were identified as significant independent prognosticators. CLU expression showed an independent prognostic relevance concerning prediction of RFS by trend (p=0.110; RR: 1.81). We conclude from our data that estimation of CLU immunoreactivity may be helpful as a supplementary criterion to better assess the tumors propensity to relapse in selected cases of breast carcinoma.

Improved non-invasive T-Staging in non-small cell lung cancer by integrated 18F-FDG PET/CT

AIM

In this prospective study, reliability of integrated (18)F-FDG PET/CT for staging of NSCLC was evaluated and compared to MDCT or PET alone.

PATIENTS, METHODS

240 patients (pts) with suspected NSCLC were examined using PET/CT. Of those patients 112 underwent surgery comprising 80 patients with NSCLC (T1 n = 26, T2 n = 37, T3 n = 11, T4 n = 6). Imaging modalities were evaluated independently.

RESULTS

MDCT, PET and PET/CT diagnosed the correct T-stage in 40/80 pts (50%; CI: 0.39-0.61), 40/80 pts (50%; CI: 0.39-0.61) and 51/80 pts (64%; CI: 0.52-0.74), respectively, whereas equivocal T-stage was found in 15/80 pts (19%; CI: 0.11-0.19), 12/80 pts (15%; CI: 0.08-0.25) and 4/80 pts (5%; CI: 0.01-0.12), respectively. With PET/CT, T-stage was more frequently correct compared to MDCT (p = 0.003) or PET (p = 0.019). Pooling stages T1/T2, T-stage was correctly diagnosed with MDCT, PET and PET/CT in 54/80 pts (68%; CI: 0.56-0.78), 56/80 pts (70%; CI: 0.59-0.80) and 65/80 pts (81%; CI: 0.71-0.89). T3 stage was most difficult to diagnose. T3 tumors were correctly diagnosed with MDCT in 2/11 pts (18%; CI: 0.02-0.52) versus 0/11 pts (0%; CI: 0.00-0.28) with PET and 5/11 pts (45%; CI: 0.17-0.77) with PET/CT. In all imaging modalities, there were no equivocal findings for T4 tumors. Of these, MDCT found the correct tumor stage in 4/6 pts (67%; CI: 0.22-0.95), PET in 3/6 pts (50%; CI: 0.12-0.88) and PET/CT in 5/6 pts (83%; CI: 0.36-0.99).

CONCLUSION

Integrated PET/CT was significantly more accurate for T-staging of NSCLC compared to MDCT or PET alone. The advantages of PET/CT are especially pronounced combining T1- and T2-stage as well as in advanced tumors.

Respiratory motion compensation with tracked internal and external sensors during CT-guided procedures

This paper investigates the possibility of using the motion of a patient's anterior surface in combination with a motion model to compensate for internal respiratory motion during tracked biopsies. Position data from two electromagnetically tracked sensors, one placed on the patient's sternum, the other incorporated into a biopsy needle, were acquired during a liver biopsy. The data were used to evaluate the correlation between the position measurements of the two sensors and to derive an affine motion model to assess respiratory motion compensation for image-guided interventional procedures. The correlation reached up to 94% for ranges of steady respiration. The residual motion of the internal sensor after compensation is reduced by a factor of approximately four.

Respiratory motion compensation with tracked internal and external sensors during CT-guided procedures

This paper investigates the possibility of using the motion of a patient's anterior surface in combination with a motion model to compensate for internal respiratory motion during tracked biopsies. Position data from two electromagnetically tracked sensors, one placed on the patient's sternum, the other incorporated into a biopsy needle, were acquired during a liver biopsy. The data were used to evaluate the correlation between the position measurements of the two sensors and to derive an affine motion model to assess respiratory motion compensation for image-guided interventional procedures. The correlation reached up to 94% for ranges of steady respiration. The residual motion of the internal sensor after compensation is reduced by a factor of approximately four.

Use of integrated FDG PET/CT imaging in pulmonary carcinoid tumours

BACKGROUND

Integrated positron emission tomography (PET)/computed tomography (CT) scanners have been recently introduced in the diagnostic work-up of suspected pulmonary malignancy and demonstrate encouraging results in the staging of nonsmall-cell lung cancer.

OBJECTIVE

To evaluate the usefulness of integrated FDG PET/CT in pulmonary carcinoid tumours.

SETTING

University hospital.

METHODS

We studied 13 patients (mean age +/- 1 SD, 57 +/- 11 years) with pulmonary carcinoid tumours. All patients demonstrated a single pulmonary lesion. Integrated PET/CT scan and surgical resection were performed in all patients.

RESULTS

The pulmonary lesion size ranged from 1.1 to 5.0 cm. Final histological diagnosis confirmed 12 typical and one atypical pulmonary carcinoid. Mean proliferation rate of the typical carcinoids was 1.7 +/- 1.4%. None of the patients had recurrent carcinoid disease or died during follow-up (864 +/- 218 days). Mean standardized uptake value (SUV) of (18)F-fluorodeoxyglucose (FDG) in typical carcinoids was 3.0 +/- 1.5 (range 1.2 - 6.6); SUV in the atypical carcinoid was remarkably high with a value of 8.5. The SUV was lower than 2.5 in 6 of 12 patients (50%). Mediastinal lymph node metastases or extrathoracic metastases were not detected in any patient.

CONCLUSIONS

(18)F-fluorodeoxyglucose PET/CT imaging improves accurate localization of metabolic activity and thus the interpretation of pulmonary lesions on CT. FDG uptake in pulmonary carcinoid tumours is often lower than expected for malignant tumours. Therefore, surgical resection or biopsy of lesions suspected to be carcinoids should be mandatory, even if they show no hypermetabolism on FDG PET images.

[Combination treatment with antisense oligonucleotides and chemotherapy in vitro]

Oncological therapy strategies are increasingly concentrating on the causal, molecular changes involved in carcinogenesis. So called "smart drugs" such as antisense oligoneucleotide (AsON) can be used as specific inhibitors of individual genes. AsONs have shown their effectiveness in many studies. Clinical studies have demonstrated, however, that for many tumours the inhibition of a single gene is, due to multigenetic alteration, largely ineffective. The combination of AsONs with conventional chemotherapeutic agents is currently being investigated in phase III studies. In these studies, chemotherapeutic agents have been evaluated in cell culture together with AsON against the proliferation associated Ki-67 gene, as well as against the apoptosis associated bcl-2 gene via RT-PCR, immunochemistry and MTT cell viability assay. For both AsONs, significant target inhibition was achieved in cell culture with a high target gene expression. The prior treatment of tumour cells with bcl-2 AsON significantly increased the effectiveness of chemotherapy, while the combination of conventional chemotherapeutic agents with Ki-67 AsON showed no synergistic effects.

Multi-organ affecting CMV-associated cryoglobulinemic vasculitis

We report on a 67-year-old female patient who was admitted to our intensive care unit with acute renal failure and severe hypoxemia. Transiently, the patient had to be treated with kidney replacement therapies and artificial ventilation. The actual illness started with general weakness, recurrent bloody diarrhea and intermittent dermatitis of the lower legs. Skin symptoms were initially observed 2 years before the actual clinical findings. The bloody diarrhea was attributed to an inflammatory stenosis of the sigma. The life-threatening clinical aggravation was due to diffuse alveolar hemorrhage and alveolitis. In the search for the cause of the systemic disease, both a monoclonal y-globulinemia, causing a cryoglobulinemia type II and an acute cytomegalovirus infection were diagnosed. Additionally, the course of the disease was complicated by a secondary antibody deficiency as well as an endocarditis of the aortic valve caused by Enterococcus faecium. A cryoglobulinemic vasculitis type II was histologically found in biopsy specimen of the kidney. Thus, the present case reports on a coincidence of a monoclonal gammopathy causing a cryoglobulinemia type II with extensive organ involvement and a florid CMV infection. We hypothesize that the CMV infection has triggered the cryoglobulinemia and its particular severe organ involvement.

[Bone formation in the ureter. Osseous metaplasia of an obstructed ureter]

Bone formation outside the skeleton is well known. Yet, ossification within the urogenital tract is rare. The case of a patient with distal ureteral obstruction, hydronephrosis, and subsequent circular osseous metaplasia of the ureter is presented. Open transperitoneal right-sided nephrectomy with partial resection of the ureter was performed. Intraoperatively and in histopathologic examination circular bone formation adjacent to the ureteral wall was detected. There was no evidence of malignancy. Early animal experiments in the twentieth century showed that bone metaplasia may be induced by epithelium of the urinary tract under certain conditions such as ischemia, inflammation, necrosis, sclerosis, and trauma. Osseous metaplasia may therefore be considered a differential diagnosis of calcification of the upper urinary tract in the absence of urolithiasis.

[Odontogenic tumors in childhood - case report and review of literature]

BACKGROUND

Odontogenic tumors are a heterogenic group of neoplasias of the oral cavity, whose biological behaviour reaches from true hamartomas to highly malignant tumors.

PATIENT

We describe the case of a 4 year old caucasian girl presenting with eruption disturbance of a primary tooth and corresponding maxillary tumor. After surgical removal of the mass, histological examination classified the tumor as ameloblastic fibroodontoma. This very rare neoplasm is of odontogenic origin.

DISCUSSION

Following our case report, the variety of odontogenic tumors regarding tumor biology, clinical symptoms and therapeutic options in childhood are discussed.

CONCLUSION

In case of complaints or clinical symptoms paediatricians should take the possibility of such neoplasias into consideration.

The p53 codon 72 variation is associated with the age of onset of hereditary non-polyposis colorectal cancer (HNPCC)

The polymorphic variants at codon 72 of the p53 gene were shown to be functionally distinct in vitro, whereby the arginine (arg) variant induces apoptosis more efficiently than the proline (pro) variant. From the evidence that the DNA mismatch repair system and p53 interact to maintain genomic integrity, we hypothesized that the codon 72 variation may influence the age of onset of disease in HNPCC patients. We tested 538 patients for p53 codon 72 variants, including 167 unrelated patients with pathogenic germline mutations in MSH2 or MLH1 and colorectal carcinoma as first tumour, 126 patients with sporadic microsatellite stable colorectal cancers, and 245 healthy controls. The median age of onset was 41, 36, and 32 years for MSH2 or MLH1 mutation carriers with arg/arg, arg/pro, and pro/pro genotypes, respectively. The log rank test revealed significant differences in the age of onset between arg/arg and pro/pro individuals (p = 0.0002) and in arg/pro versus arg/arg and pro/pro individuals (p = 0.0026 and p = 0.0217, respectively). A Cox regression model indicated an additive mode of inheritance. No significant differences in age of onset were observed among different genotype carriers with microsatellite stable tumours. Our results suggest that p53 codon 72 genotypes are associated with the age of onset of colorectal carcinoma in a mismatch repair deficient background in a dose dependent manner. These findings may be relevant for preventive strategies in HNPCC.

Effects of the angiogenesis inhibitor angiostatin on the growth of CC531 colon carcinoma cells in vitro and in a laparoscopic animal model of peritoneal carcinomatosis

BACKGROUND

As angiogenesis is one of the key steps in tumor growth, invasion, and metastasis, antiangiogenic therapy is supposed to be an attractive approach for antitumor treatment. We investigated the cytotoxic, anti-adhesive, and anti-invasive effects of angiostatin in vitro and on intraperitoneal tumor growth in a laparoscopic rat model of peritoneal carcinomatosis using CC531 colon adenocarcinoma cells.

METHODS

The in vitro adhesion and cytotoxicity assays were performed with microtiter plates, and the invasion assay with Transwell dual chambers. Normal saline was used as control. In in vivo experiments, CC531 adenocarcinoma cells were intraperitoneally given to Wistar Albino Glaxo rats after the establishment of a pneumoperitoneum. The animals received angiostatin in different doses intraperitoneally, and in some, angiostatin was additionally administered subcutaneously. Saline was used as control. After 21 days, the animals were euthanized to determine the intra-abdominal tumor weight.

RESULTS

In in vitro experiments, there was no effect of angiostatin on the viability of tumor cells in the cytotoxicity assay, but there was a significant inhibition of tumor cell adhesion and invasion (p<0.05 and p<0.01) in all angiostatin concentrations. In in vivo experiments, an intraperitoneal application of 20 microg angiostatin, but not 10 microg, significantly (p<0.005) decreased the intraperitoneal tumor weight compared with controls. This effect was most pronounced after the combined intraperitoneal and subcutaneous applications.

CONCLUSION

Angiostatin given intraperitoneally at a dose of 20 microg alone or in combination with subcutaneous application significantly diminishes intraperitoneal tumor growth in rats undergoing laparoscopy. This may offer additional therapeutic options for patients undergoing laparoscopic surgery for colorectal cancer.

Localized nodular pigmented villonodular synovitis of the upper ankle joint – diagnosis and treatment

This paper introduces a case of local pigmented villonodular synovits (PVNS) of the upper ankle joint in a 37-year old patient. PVNS is a neoplasia of the synovial membrane. Two different entities of PVNS are known: generalized diffuse and local nodular. They differ in their degree of destruction and growth configuration, which is crucial for prognosis and operative treatment. The most common location of the local nodular form is the knee joint, followed by the finger joints. Occurrence in the ankle joint is not common but should be considered if clinical findings are present. MRI is the method of choice for diagnosis and assessment of the bone situation. Treatment consists of radical excision of the neoplasia. Radiosynoviorthesis is recommended as a post-operative treatment to increase the probability of a total removal of persisting PVNS cells. The rate of recurrence seems to be between 8 and 46%.

Relationship between donor factors, immunogenic up-regulation, and outcome after kidney transplantation

Epidemiological data show that the cause of brain death as well as the condition of the organ donor have considerable influence on the outcome of kidney transplantation. An early immunogenic up-regulation, which already exists at the time of organ removal seems to be primarily responsible. So far it has remained unclear which donor factors cause this effect. In a prospective study of 37 organ donors a 0-hour biopsy was performed at the time of explantation to measure the expression of HLA-DR and endothelin-1 (ET-1) immunohistologically using the alkaline phosphatase anti-alkaline phosphatase (APAAP) method. The transplant outcome and the immunohistological results were correlated with various donor factors. Statistically significant correlations were seen with the following parameters: the donor serum creatinine prior to explantation correlated with the incidence of delayed graft function (DGF: 104 +/- 39 vs 78 +/- 35 micromol/L versus no DGF n = 37; P = .043). Early graft loss after transplantation correlated significantly with increased numbers of leukocytes as well as with decreased O2 saturation in the donor immediately before explantation (leucocytes: 16.7 +/- 6.8 vs 12.6 +/- 4.6/nL, n = 37; P = .036; O2 saturation: 94.1% +/- 6.9%, vs 97.7% +/- 2.3%, n = 37; P = .026). Further, donor-independent factors that correlated with acute rejections included cold ischemic time (P = .031), HLA mismatches (P = .028), and occurrence of DGF (P = .033). The degree of HLA-DR expression (range 0 to 2) correlated significantly with early graft loss (2.0 +/- 0.2 vs 1.33 +/- 0.9 for graft function, n = 37; P = .01) as well as the ET-1 expression with DGF (2.0 +/- 0.3 vs 1.5 +/- 0.7 versus no DGF, n = 37; P = .016). In summary, marginal donors should be seen as high immunological risk situations that need careful conditioning.

Proteolysis of serum amyloid A and AA amyloid proteins by cysteine proteases: cathepsin B generates AA amyloid proteins and cathepsin L may prevent their formation

BACKGROUND

AA amyloidosis develops in patients with chronic inflammatory diseases. The AA amyloid proteins are proteolytic fragments obtained from serum amyloid A (SAA). Previous studies have provided evidence that endosomes or lysosomes might be involved in the processing of SAA, and contribute to the pathology of AA amyloidosis.

OBJECTIVE

To investigate the anatomical distribution of cathepsin (Cath) B and CathL in AA amyloidosis and their ability to process SAA and AA amyloid proteins.

METHODS

and results: CathB and CathL were found immunohistochemically in every patient with AA amyloidosis and displayed a spatial relationship with amyloid in all the cases studied. Both degraded SAA and AA amyloid proteins in vitro. With the help of mass spectrometry 27 fragments were identified after incubation of SAA with CathB, nine of which resembled AA amyloid proteins, and seven fragments after incubation with CathL. CathL did not generate AA amyloid-like peptides. When native human AA amyloid proteins were used as a substrate 26 fragments were identified after incubation with CathB and 18 after incubation with CathL.

CONCLUSION

The two most abundant and ubiquitously expressed lysosomal proteases can cleave SAA and AA amyloid proteins. CathB generates nine AA amyloid-like proteins by its carboxypeptidase activity, whereas CathL may prevent the formation of AA amyloid proteins by endoproteolytic activity within the N-terminal region of SAA. This is particularly interesting, because AA amyloidosis is a systemic disease affecting many organs and tissue types, almost all of which express CathB and CathL.