Computer-aided pulmonary nodule detection - performance of two CAD systems at different CT dose levels.

PURPOSE: To evaluate the impact of dose reduction on the performance of computer-aided lung nodule detection systems (CAD) of two manufacturers by comparing respective CAD results on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT). MATERIALS AND METHODS: Multi-slice computed tomography (MSCT) data sets of 26 patients (13 male and 13 female, patients 31 - 74 years old) were retrospectively selected for CAD analysis. Indication for CT examination was staging of a known primary malignancy or suspected pulmonary malignancy. CT images were consecutively acquired at 5 mAs (ULD-CT) and 75 mAs (SD-CT) with 120 kV tube voltage (1 mm slice thickness). The standard of reference was determined by three experienced readers in consensus. CAD reading algorithms (pre-commercial CAD system, Philips, Netherlands: CAD-1; LungCARE, Siemens, Germany: CAD-2) were applied to the CT data sets. RESULTS: Consensus reading identified 253 nodules on SD-CT and ULD-CT. Nodules ranged in diameter between 2 and 41 mm (mean diameter 4.8 mm). Detection rates were recorded with 72 % and 62 % (CAD-1 vs. CAD-2) for SD-CT and with 73 % and 56 % for ULD-CT. Median false positive rates per patient were calculated with 6 and 5 (CAD-1 vs. CAD-2) for SD-CT and with 8 and 3 for ULD-CT. After separate statistical analysis of nodules with diameters of 5 mm and greater, the detection rates increased to 83 % and 61 % for SD-CT and to 89 % and 67 % for ULD-CT (CAD-1 vs. CAD-2). For both CAD systems there were no significant differences between the detection rates for standard and ultra-low-dose data sets (p > 0.05). CONCLUSION: Dose reduction of the underlying CT scan did not significantly influence nodule detection performance of the tested CAD systems.

Linear and volume measurements of pulmonary nodules at different CT dose levels - intrascan and interscan analysis.

PURPOSE: To compare the interobserver variability of the unidimensional diameter and volume measurements of pulmonary nodules in an intrascan and interscan analysis using semi-automated segmentation software on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT) data. MATERIALS AND METHODS: In 33 patients with pulmonary nodules, two chest multi-slice CT (MSCT) datasets (1 mm slice thickness; 20 % reconstruction overlap) had been consecutively acquired with an ultra-low dose (120 kV, 5 mAs) and standard dose technique (120 kV, 75 mAs). MSCT data was retrospectively analyzed using the segmentation software OncoTREAT (MeVis, Bremen, Germany, version 1.3). The volume of 229 solid pulmonary nodules included in the analysis as well as the largest diameter according to RECIST (Response Evaluation Criteria for Solid Tumors) were measured by two radiologists. Interobserver variability was calculated and SD-CT and ULD-CT data compared in an intrascan and interscan analysis. RESULTS: The median nodule diameter (n = 229 nodules) was registered with 8.2 mm (range: 2.8 to 43.6 mm, mean: 10.8 mm). The nodule volume ranged between 0.01 and 49.1 ml (median 0.1 ml, mean 1.5 ml). With respect to interobserver variability, the intrascan analysis did not reveal statistically significant differences (p > 0.05) between ULD-CT and SD-CT with broader limits of agreement for relative differences of RECIST measurements (-31.0 % + 27.0 % mean -2.0 % for SD-CT; -27.0 % + 38.6 %, mean 5.8 % for ULD-CT) than for volume measurements (-9.4 %, 8.0 %, mean 0.7 % for SD-CT; -13 %, 13 %, mean 0.0 % for ULD-CT). The interscan analysis showed broadened 95 % confidence intervals for volume measurements (-26.5 % 29.1 % mean 1.3 %, and -25.2 %, 29.6 %, mean 2.2 %) but yielded comparable limits of agreement for RECIST measurements. CONCLUSION: The variability of nodule volumetry assessed by semi-automated segmentation software as well as nodule size determination by RECIST appears to be independent of the acquisition dose in the CT source dataset. This is particularly important regarding size determination of pulmonary nodules in screening trials using low-dose CT data for follow-up imaging.

High-resolution T2-weighted abdominal magnetic resonance imaging using respiratory triggering: impact of butylscopolamine on image quality.

BACKGROUND: Respiratory triggering allows the acquisition of high-resolution magnetic resonance (MR) images of the upper abdomen. However, the depiction of organs close to the gastrointestinal tract can be considerably impaired by ghosting artifacts and blurring caused by bowel peristalsis. PURPOSE: To evaluate the effect of gastrointestinal motion suppression by intramuscular butylscopolamine administration on the image quality of a respiratory-triggered T2-weighted turbo spin-echo (T2w TSE) sequence of the upper abdomen. MATERIAL AND METHODS: Images of 46 patients were retrospectively analyzed. Twenty-four patients had received intramuscular injection of 40 mg butylscopolamine immediately before MR imaging. Fourteen of the 24 patients in the butylscopolamine group underwent repeat imaging after a mean of 29 min. Quantitative analysis of the ghosting artifacts was done by measuring signal intensities in regions of interest placed in air anterior to the patient. In addition, image quality was assessed qualitatively by two radiologists by consensus. RESULTS: Spasmolytic medication with butylscopolamine reduced ghosting artifacts and significantly improved image quality of the respiratory-triggered T2w TSE sequence. The most pronounced effect of butylscopolamine administration on image quality was found for the pancreas and the left hepatic lobe. The rate of examinations with excellent or good depiction of the pancreas and the left hepatic lobe in the group without premedication and in the butylscopolamine group was 55% vs. 96% (pancreatic head), 35% vs. 88% (pancreatic body), 43% vs. 96% (pancreatic tail), and 45% vs. 83% (left hepatic lobe), respectively. Regarding the duration of the effect of intramuscular butylscopolamine, repeat imaging after a mean of 29 min did not result in a significant deterioration of image quality. CONCLUSION: Intramuscular butylscopolamine administration significantly improves image quality of respiratory-triggered T2-weighted abdominal MR imaging by persistent reduction of peristaltic artifacts. MR imaging of the liver and pancreas in particular benefits from the suppression of gastrointestinal peristalsis by butylscopolamine.

Cine magnetic resonance imaging of the small bowel: comparison of different oral contrast media.

PURPOSE: To evaluate several substances regarding small bowel distension and contrast on balanced steady-state free precession (bSSFP) cine magnetic resonance (MR) images. MATERIAL AND METHODS: Luminal contrast was evaluated in 24 volunteers after oral application of two different contrast agent groups leading to either bright lumen (pineapple, blueberry juice) or dark lumen (tap water, orange juice) on T1-weighted images. Bowel distension was evaluated in 30 patients ingesting either methylcellulose or mannitol solution for limiting intestinal absorption. Fifteen patients with duodeno-jejunal intubation served as the control. Quantitative evaluation included measurement of luminal signal intensities and diameters of four bowel segments, qualitative evaluation assessed luminal contrast and distension on a five-point scale. RESULTS: Quantitative and qualitative evaluation of the four contrast agents revealed no significant differences regarding luminal contrast on bSSFP images. Quantitative evaluation revealed significantly lower (P<0.05) small bowel distension for three out of four segments (qualitative evaluation: two out of four segments) for methylcellulose in comparison to the control. Mannitol was found to be equal to the control. CONCLUSION: Oral ingestion of tap water or orange juice in combination with mannitol is recommended for cine MR imaging of the small bowel regarding luminal contrast and small bowel distension on bSSFP sequences.

[Whole-body MR angiography: comparison of two protocols for contrast media injection]. / Ganzkörper-MR-Angiographie: Vergleich von zwei Protokollen zur Kontrastmittelinjektion.

PURPOSE: To compare two injection strategies for contrast media injection in whole-body MR angiography quantitatively and qualitatively with regard to contrast and image quality. MATERIAL AND METHODS: 40 patients were examined at 1.5 Tesla using either a single injection protocol or a double injection protocol with two separate bolus injections. Vessel regions I (supraaortic/thoracic), II (abdominal/pelvic), III (upper legs) and IV (lower legs) were examined in the following order: single injection: I, II, III, IV, double injection: I and IV after the first injection, II and III after the second bolus injection. Quantitative evaluation: SI measurements were carried out in 2 arteries per region. Contrast values were calculated. Qualitative evaluation: Evaluation of regions I-IV regarding vessel contrast, venous overlay and image quality on a five-point scale by two reviewers in consensus. The Mann-Whitney-U test was used to test the differences for significance. RESULTS: Quantitative evaluation: Using the double injection protocol, significantly higher contrast values in regions I and II and significantly lower contrast values in the subregions IIIa (upper part of III) and IVb (lower part of IV) were obtained (p < 0.05). The mean contrast values in subregions IIIb (lower part of III) and IVa (upper part of IV) were lower using the double injection protocol, but not significantly. Qualitative evaluation: Using the double injection protocol, region II was rated significantly higher (mean ratings: 3.55, 3.45 and 3.5 versus 2.7, 2.5 and 2.55; p < 0.05) and region III significantly lower (mean ratings: 3.1, 2, 2.5 versus 3.9, 3.1 and 3.55; p < 0.05) for all three examined criteria. When using the double injection protocol, ratings were significantly lower in region IV regarding vessel contrast and image quality (mean ratings: 2.4 and 2.15 versus 3.45 and 3.15; p < 0.05). The ratings regarding venous overlay in region IV showed no significant differences (mean ratings: 2.15 versus 2.75; p > 0.05). CONCLUSION: Due to the better results in the supraaortic/thoracic and abdominal/pelvic regions, the double injection protocol is preferred. However, both protocols require further improvement.

Distribution and colocalization of markers for proliferation, invasion, motility and neoangiogenesis in benign melanocytic naevi and malignant melanomas.

BACKGROUND: Melanomas are heterogeneous tumours, and differentiation from other melanocytic lesions may cause problems. It may be possible that the distribution and/or colocalization pattern of different markers in the lesions can enable a more accurate diagnosis of melanocytic tumours. OBJECTIVES: To test this hypothesis, melanocytic naevi, primary melanomas and metastases were investigated. METHODS: The distribution and colocalization of markers for proliferation, invasion, angiogenesis and motility of the tumour cells were investigated using antibodies directed against actin, cathepsin B (CatB), transforming growth factor-beta, vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen/Ki-67 and basic fibroblast growth factor (FGF-2). In addition, melanoma markers (HMB-45 and Melan-A) and proteins unrelated to melanoma progression [epidermal growth factor (EGF) and cathepsin H] were investigated. RESULTS: Malignant melanomas tended to express more markers of malignancy compared with melanocytic naevi, and the differences were statistically significant for EGF and actin immunoreactivity: melanocytic naevi displayed clear EGF labelling more often (60% vs. 5%) and melanomas showed more intense actin labelling (70% vs. 0%). HMB-45+ cells to a large extent also stained with antibodies to CatB but not to EGF or actin; EGF-, FGF-2- and VEGF-immunoreactive cells were predominantly HMB-45-. Similar combinations were observed in melanocytic naevi and in melanomas. CONCLUSIONS: Labelling with EGF may improve the differential diagnosis of melanocytic neoplasias. However, we did not detect a clear-cut increase of markers of malignancy in melanoma. Cells expressing multiple malignancy markers were also found in some melanocytic naevi; this may confirm the dormant potential of melanocytic naevi for melanoma development.

[Surgery for congestive heart failure--the role of computed tomography in the pre- and postoperative diagnostic evaluation]. / Chirurgie der Herzinsuffizienz -- Stellenwert der Computertomographie in der prä- und postoperativen Diagnostik.

The treatment of advanced, drug resistant congestive heart failure gains in importance in the field of cardiac surgery. Cardiac imaging for preoperative assessment and follow-up focuses on the determination of ventricular volumes and function as well as on the detection of postoperative complications. Computed tomography (CT) is highly accurate irrespective of the individual patient's anatomic situation, has a low examiner dependence and short examination time, does not require an arterial vascular access and can be performed in patients with metal implants. CT is the modality of choice in the follow-up of heart transplants to detect extracardiac and cardiac complications including coronary calcifications as an early sign of transplant vasculopathy. In addition, CT visualizes the elements of mechanical assist devices and can identify their possible local cardiac and mediastinal complications. CT can detect fibrolipomatous involution of the mobilized muscle flap in dynamic cardiomyoplasty and can depict fibrous reactions along the epicardial mesh implant in passive cardiac containment. Further indications include assessment of typical local postoperative complications, such as intrathoracic infection and mediastinal bleeding, intracardiac thrombus formation or pericardial effusion. CT is routinely used for evaluating bypass patency but is limited in assessing associated valve defects since it does not visualize flow.

[Transarterial embolization for uterine fibroids: clinical success rate and results of magnetic resonance imaging]. / Transarterielle Embolisation bei Uterus myomatosus: klinische Erfolgsrate und kernspintomographische Ergebnisse.

PURPOSE: To analyze the clinical success rate and the findings of magnetic resonance imaging (MRI) after uterine artery embolization of symptomatic leiomyomas (fibroids) of the uterus. MATERIALS AND METHODS: This is a prospective single-center case study of 80 consecutively treated patients, followed for 3 - 6 months (group I), 7 - 12 months, (group II), and 13 - 25 months (group III). MRI was used to determine the uterine volume and size of the dominant leiomyoma. Symptoms and causes requiring repeat interventions were analyzed. RESULTS: Significant (p < 0.01) volume reduction of the uterus (median: 34.95 % confidence interval [CI]: 30.41 - 41.76 %) and dominant leiomyoma (median: 52.07 %, CI: 47.71 - 61.57 %) was found. The decrease in uterine volume (I-III: 22.68 %, 33.56 %, 47.93 %) and dominant leiomyoma volume (I-III: 41.86 %, 62.16 %, 73.96 %) progressed with the follow-up time. Bleeding resolved significantly (p < 0.0001) in all three follow-up groups (groups I-III: 92.86 %, 95.23 %, 96.67 %). Furthermore, urinary frequency (groups I-III: 70 %, 75 %, 82.35 %) and sensation of pelvic pressure (groups I-III: 42.86 %, 60 %, 93.75 %) improved, which was statistically significant in group III (p < 0.01). The number of leiomyomas correlated (p < 0.05) with improvement of the bleeding and the pelvic pressure. Repeat therapy was necessary for complications in four patients (5 %) and for therapeutic failure in three patients (3.8 %). Permanent amenorrhea was observed in four patients (5 %) of age 45 years or older. CONCLUSION: Uterine artery embolization of uterine leiomyomas has a high clinical success rate with an acceptable incidence of complications and repeat interventions.

Complex genital malformation in a female with congenital adrenal hyperplasia: evaluation with magnetic resonance imaging.

This is a case of complex genital malformation in a young patient with congenital adrenal hyperplasia. The magnetic resonance imaging (MRI) findings included ostium of the vagina into the urethra (common urogenital opening), prostate-like tissue surrounding the urethra, and hyperplasia of the left adrenal gland. The report provides information on the clinical findings, the MRI examination, including the applied sequences and the MR findings, and gives an overview of the disease pattern and its frequency of occurrence.

Cathepsins in basal cell carcinomas: activity, immunoreactivity and mRNA staining of cathepsins B, D, H and L.

In the majority of neoplasms invasion is inevitably linked to metastasis and even small tumors have the dormant potential for metastasis. In basal cell carcinoma (BCC) invasion can be evaluated separately because local invasion but no metastasis occurs. Important proteases in invasion and metastasis are the cathepsins. Their activity and regulation has not yet been evaluated in BCC. We determined the activities, immunoreactivities and mRNA of cathepsins B, L and H in sections of different subtypes of BCC. BCC cells and peritumoral cells contained activities for cathepsins B and L. In all parts of the tumor, the reaction with cathepsin B and L substrate was stronger than in normal skin. The immunoreactive protein and mRNA for these proteases, in contrast, was elevated only occasionally in small tumor nodules. Immunoreactive protein and mRNA of cathepsin D was detected predominantly in the center of tumor nodules. Cathepsin H activities, immunoreactivities and mRNA in most BCCs were higher than in normal skin, and the reactive cells were located between and around tumor nodules, but not in the tumor nests. The results indicate that cathepsins B and L are involved in invasion of BCC cells. Cathepsin H of the peritumoral cells may either promote invasion of the tumor cells by degradation of the extracellular matrix or may reflect an elevated activity of the surrounding immunological cells. The pattern of cathepsin staining markedly differs from that observed in melanomas and may characterize locally invading non-metastatic tumors.

Activity, expression, and transcription rate of the cathepsins B, D, H, and L in cutaneous malignant melanoma.

BACKGROUND: Increased activity of the protease cathepsin B has been demonstrated in many tumor cells. A correlation of cathepsin B activity and metastatic potential of melanoma has been well established. METHODS: The cathepsins B, D, H, and L were evaluated in normal skin, nevi, and melanoma samples to obtain information about their role and their regulation in melanoma. The authors localized specific proteolytic activity with histochemistry, cathepsin protein immunohistochemistry, and mRNA with in situ hybridization. RESULTS: Activities and immunoreactivities of the cathepsins B and L were found to be increased in all melanocytic lesions. However, the staining for the corresponding mRNA levels was elevated only in melanomas. Cathepsin D protein and mRNA were expressed to a higher degree only in the dysplastic nevus and in melanomas. The increase was due to tumor cells and cells of the surrounding tissue. Cathepsin H activity, immunoreactivity, and mRNA appeared to be correlated inversely with the invasive potential of the lesion. CONCLUSIONS: It may be relevant for the malignant potential of the lesion whether the increase in activity is accompanied by an increase in the mRNA level. Two different mechanisms-the existence of different mRNAs and the higher transcription rate of the cathepsin gene-have been proposed for the regulation of cathepsin B activity in tumor cells. The current data suggest that, depending on the thickness of the melanoma, cathepsin activity is regulated by different mechanisms. The up-regulation of cathepsin gene transcription appears to be characteristic for more invasive tumor cells.

Enzymatic heterogeneity of bovine retinal pigment epithelial cells in vivo and in vitro.

BACKGROUND: The retinal pigment epithelium (RPE) contains a variety of enzymes that are involved in the metabolism of the neural retina. It has been shown that the photoreceptor densities display regional variations. We aimed to find out whether the enzymes in the RPE also display regional differences. METHODS: Various enzymes were localized in RPE cells in situ and in cultured RPE cells. RPE cells of the entire tapetal region of adult and fetal bovine eyes were examined. The following enzymes were studied: Activities of aminopeptidases A and M, dipeptidylpeptidases I and II, and gamma-glutamyltranspeptidase were localized by histochemistry. Alkaline phosphatase, dipeptidylpeptidase IV, and cathepsin B were studied by histochemistry and immunocytochemistry. In addition, activities of two enzymes were localized in one cell. RESULTS: The distribution pattern of the enzymatic activities showed no marked regional differences. In contrast, pronounced cell-to-cell variability in the activities was detected for some of the enzymes tested. These intercellular differences were detected already in fetal retinae of early stages and persisted in RPE cultures. CONCLUSION: The heterogeneous distribution of enzymatic activities in RPE cells appears not to be caused exclusively by stimuli from the neural retina and from the choroid, because heterogeneity starts in the early fetal period and persists in culture.

Glutamine synthetase and marker enzymes of the blood-retina barrier in fetal bovine retinal pigment epithelial cells.

BACKGROUND: Glutamine synthetase is involved in the recycling of synaptically released glutamate and GABA and in the detoxification of ammonia. It is present in the Müller cells of the neural retina but not in the retinal pigment epithelial (RPE) cells of adult mammals. In human retinal pathological conditions glutamine synthetase has also been detected in RPE cells. In this case glutamine synthetase may provide the cells with glutamine needed for proliferation. Proliferation is also intense during retinal development. METHODS: We studied the distribution of glutamine synthetase immunoreactivity in fetal bovine retinae, especially in the RPE. The maturity of the RPE was demonstrated by histochemical detection of gamma-glutamyltranspeptidase, alkaline phosphatase and Na/K-ATPase as marker enzymes for the blood-retina barrier and by electron microscopy. RESULTS: We found that in the first 3 months of gestation glutamine synthetase immunoreactivity is located exclusively in the RPE. During the 3rd month the marker enzymes of the blood-retina barrier begin to appear. From the 4th month on, RPE cells are glutamine synthetase immunonegative. CONCLUSION: Glutamine in RPE cells in early development may supply glutamine for the intensely proliferating cells in the retina. Glutamine synthetase immunoreactivity in human retinal pathological conditions may indicate reinduction of an enzyme used in earlier development.

Depiction of anomalous coronary vessels and their relation to the great arteries by magnetic resonance angiography.

Three-dimensional respiratory-gated coronary MR angiography (MRA) allowed accurate analysis of the anatomy of the coronary arteries and their relation to the adjacent anatomic structures in two patients with anomalous origin and proximal course of the coronary vessels. Together with functional tests, it decisively influenced further therapy.

[Thrombosis of the deep leg and pelvic veins in congenital agenesis of the vena cava inferior]. / Thrombose der tiefen Bein- und Beckenvenen bei angeborener Agenesie der Vena cava inferior.

HISTORY AND ADMISSION FINDINGS: Severe pain and increasing swelling in the region of the right lower leg occurred after unaccustomed physical activity in a 29-year-old man. Physical examination showed painful swelling and livid discoloration of the right lower leg. INVESTIGATIONS: Laboratory tests were consistent with an acute inflammation. Colour Doppler duplex sonography of the leg and pelvic veins bilaterally revealed complete thrombosis of the deep leg and pelvic veins on the right. Spiral computed tomography of the abdomen confirmed deep pelvic vein thrombosis and also demonstrated complete agenesis of the inferior vena cava (IVC). TREATMENT AND COURSE: The patient was fully heparinized and compression bandage applied to the right leg, which was kept elevated, Ibuprofen, 3 x 400 mg daily, was given for pain relief. Anticoagulation treatment with phenprocoumon (Marcumar) was initiated. The patient was discharged much improved after ten days. Duplex sonography after 3 months demonstrated partial recanalization of the right pelvic and deep leg veins. CONCLUSION: Congenital malformations of the IVC are rare. Phlebothrombosis often results in affected patients. Treatment or prevention of thrombosis of the deep veins by anticoagulation is indicated. Additional risk factors for thrombosis--smoking, hormonal contraceptives, immobilization and unusual physical activity--should be strictly avoided.

A computer based, temperature controlled bipolar electrocoagulation system.

OBJECTIVE: To reduce complications during electrocoagulation particularly injury of other organs, a computer based, temperature controlled bipolar coagulation system has been developed. Under this system temperature in the tissue is kept between 60 degrees C and 95 degrees C during coagulation. A real time graphic display provides the surgeon with an actual temperature at the tip of the forceps during coagulation. STUDY DESIGN: Rabbit uterine horns were coagulated at 90 degrees C and were examined histologically and histochemically at 6 weeks after coagulation. RESULTS: Electrocoagulation at 90 degrees C induced a total loss of LDH activity in the tissue. Lumen of the uterus was completely occluded when examined 6 weeks later. CONCLUSION: This system with low temperature is sufficient for homogenous coagulation of the tissue.

Immunocytochemical and immunoelectron microscopic demonstration of cathepsin B in human malignant melanoma.

Proteases are known to enhance the spread of tumour cells. Possible sources of these proteases are the tumour cells themselves or fibroblasts in the tumour tissue. Immunological staining with anticathepsin B antibody indicates that the subcellular distribution of cathepsin B in tumour cell lines differs from that in normal liver. The aims of this study were: (i) to show whether different types of melanoma differ in their production of cathepsin B; (ii) to identify the cathepsin B-producing cells; and (iii) to determine the subcellular distribution of cathepsin B in melanoma cells. All types of melanomas contained cell regions stained with anticathepsin B antibody. The intensity of the stain and the number of cells reacting with anticathepsin B antibody depended on the size of the tumour but not on the type of melanoma. Epithelioid cells stained more intensely with anticathepsin B antibody than spindle-shaped cells. Cells staining with anticathepsin B antibody were almost exclusively tumour cells. Anticathepsin B stain was located mainly in vesicular structures which did not contain a filamentous matrix. Additional anticathepsin B stain was detected at the extracellular spaces. Hypomelanotic melanoma cells, mainly of the epithelioid type, produced most of the cathepsin B. Cathepsin B may be involved in both the degradation of possibly abnormal melanosomes and the focal degradation of the extracellular matrix.

Aminopeptidase M and dipeptidyl peptidase IV activity in epithelial skin tumors: a histochemical study.

The activities of microsomal alanylaminopeptidase (APM EC 3.4.11.2) and of dipeptidyl dipeptidase IV (DPP IV EC 3.4.14.5) were histochemically studied in frozen sections of normal skin, seborrheic keratosis, basal cell carcinoma, solar keratosis, Bowen's disease and squamous cell carcinoma using amino acid- or peptide-4-methoxy-2-naphthylamides as specific chromogenic substrates. Compared to biochemical and immunohistochemical methods, the histochemical technique used in this study allows distinct localization of protease activity within the tumor tissue and the tumor-associated stroma. Strong APM activity was detectable only in the stroma of basal cell carcinoma, a result which reflects the particular tumor-stroma interaction of this semimalignant tumor. APM activity was not detectable in either healthy epidermis or the tumor parenchyma. Altered activity of DPP IV was found in the tumor cells as well as in the surrounding connective tissue: precancerous dermatoses and basal cell carcinomas had higher levels of DPP IV-activity than normal skin or benign seborrheic keratosis. Poorly differentiated malignant squamous cell carcinomas, however, showed no histochemically detectable DPP IV-activity at all. This result is in line with reports of decreased activity of this enzyme in cases of malignancy.

Immunelectron microscopic localization of cathepsin B in human exocrine glands.

The distribution of the lysosomal enzymes cathepsin B, lysozyme, chymotrypsin, and neutrophil elastase was examined in eccrine, apocrine, and sebaceous glands using a postembedding immunogold labeling procedure. Various amounts of cathepsin B were detected in all glands. Lysozyme, however, was detected in apocrine glands only. The other two lysosomal enzymes were not detectable immunologically. In apocrine and eccrine glands, anti-cathepsin B antibody labeled all secretory granules. In sebaceous glands, only the peripheral layer of cells showed immunological activity for cathepsin B. In apocrine glands, granules containing remnants of cristae were more intensively labeled than those lacking cristae which supports the assumption that both granules are derived from mitochondria by acquiring lysosomal enzymes. The enzymes convert mitochondria to granules with cristae and finally to granules without cristae. Thus the difference in morphology is part of a spectrum of the degradation of mitochondria to granules.

Proteases of polymorphonuclear neutrophils: influence of different salts and buffers on pericellular lysis.

Polymorphonuclear neutrophils (PMN) contain neutral proteases which are cytochemically detectable on blood smears. The activity of these proteases can be visualized by pericellular lysis, i.e. through a disk like degradation of plasma and erythrocytes around centrally located neutrophils. This degradation is inhibited by protease inhibitors in a concentration-dependent manner. Striking differences in halo formation were found depending on the type of buffer and salt used and change of temperature. A halo formation was obtained in Tris-HCl buffer, pH 7.5 without salt, at room temperature (22 degrees C), and with short incubation periods (30 min). Borate buffer, pH 8.5, showed a comparable halo formation only at 37 degrees C, after addition of salts, and after longer incubation times (180 min). When different alkali chlorides were used, halo size increased with molecular mass. Optimum halo size was achieved at a concentration of 250 mM. Addition of MgCl2 and CaCl2 (250 mM) resulted in a small halo formation at 22 degrees C, but inhibited halo formation at 37 degrees C. The present study shows that the pericellular lysis caused around neutrophils by the release of proteases is affected by a complex interaction of salts, temperature, buffers and thermodynamic aspects, all of which should be evaluated carefully in these kinds of experiments.