[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

[Clinical autopsies. Practical approach, legal foundations and ethical considerations]

Only an autopsy can demonstrate topographical and morphological circumstances in detail and correlate the clinical and autopsy findings based on the examination of all organs. The practical approach in a fatality is described based on the example of the Lüdenscheid Hospital. A uniform legal regulation for dealing with corpses does not exist in Germany. There are two approaches to the question under which circumstances a clinical autopsy is allowed: the extended permission solution and the objection solution. Whether a clinical autopsy can be carried out is decided by the medical specialist selected on application. Autopsies can be necessary from insurance or administrative legal grounds or in the case of an anatomical autopsy is decided by the persons themselves. In order to guarantee the quality of an autopsy it is necessary to use a standardized approach with evaluation and assessment of the results, for example using a quality assurance protocol and the production of an autopsy report. Using this approach important information can be gained not only on the accuracy of the main diagnosis and cause of death but also on additional diseases, response to therapy and the course of the disease and under circumstances can lead to modifications in the approach.

Regeneration of beta-cells in response to islet inflammation

Subtotal pancreatectomy (90%) in Lewis rats induces chronic islet inflammation and tissue damage in the remaining pancreas 4 months after surgery. Concomitantly, significant enlargement of the islets of Langerhans was observed (90% pancreatectomy: islet/pancreas area: 25.6 +/- 9.6 x 10(-3), beta-cell/pancreas area: 12.4 +/- 4.4 x 10(-3); n = 4; controls without pancreatectomy: islet/pancreas area: 5.5 +/- 1.7 x 10(-3), beta-cell/pancreas area: 4.6 +/- 1.5 x 10(-3); n = 4; p < 0.05, respectively). Islet growth is mainly due to an increase in beta-cell mass. Beta-cell regeneration was not caused by the surgical manipulations or by metabolic stress. The former was ruled out by performing 10% pancreatectomy which did not cause islet enlargement after 4 months (islet/pancreas area: 13.6 +/- 11.3 x 10(-3), beta-cell/pancreas area: 7.1 +/- 2.0 x 10(-3); n = 3). An influence of metabolic stress was excluded by continuous substitution of syngenic islet antigens, which inhibits insulitis. In the absence of islet inflammation, despite persistent metabolic stress, beta-cell regeneration did not occur (islet/pancreas area: 7.0 +/- 5.5 x 10(-3), beta-cell/pancreas area: 5.5 +/- 4.1 x 10(-3); n = 4). Continuous treatment of animals after 90% pancreatectomy by insulin implants (1.5 U/day) avoided insulitis and beta-cell growth (islet/pancreas area: 9.2 +/- 1.1 x 10(-3), beta-cell/pancreas area: 6.8 +/- 1.0 x 10(-3), n = 3): All enlarged islets observed 4 months after 90% pancreatectomy without further treatment were infiltrated. Thus, beta-cell growth appears to be a response to insulitis. The stimulus for beta-cell growth could result from tissue damage caused by infiltrating cells or from cytokines secreted by the infiltrating cells, or both.

[Synovial membrane diagnostic assessment in rheumatoid arthritis]

Rheumatoid arthritis (RA) is the most frequent inflammatory rheumatic disease. At the beginning of the disease, where, based on today's knowledge the therapeutic possibilities are largest, the diagnostic methods do not permit a differentiated estimation of the prognosis. Conventional x-rays are mostly normal and serum markers unspecific. So far--in contrast to other diseases--only little information had been drawn from the pathomorphologic substrate "synovialis" itself to assess the prognosis. Reasons therefor were found in difficulties in obtaining synovial tissue besides surgical interventions, particularly in patients with early arthritis. By minimalizing the diagnostic instruments and improvement of the technique, synovial tissue sampling in RA has become minimally invasive and it is even possible to perform on the smallest joints, such as finger joints. Hereby, synovial analysis is open for detecting pathways of inflammation and joint destruction, which might support the advancement of new therapeutic strategies, followed by a better prognosis and outcome of RA.

[Iatrogenic "metalloma" (titanoma) caused by implant failure in "metal-backed" patellar joint surface replacement]

Patellofemoral problems frequently provide the cause for revisions after total knee replacements (TKR). Problems with metal-backed patellae, in particular, have been reported on in the past, with a failure rate of 33%. As a result of implant failure, there is an increase of polyethylene and metallic wear, which eventually leads to a synovialitis and metallosis. We report a case of a iatrogenic induced metallosis of the knee joint resulting from failure of a metal-backed patella component with the formation of a substantial pseudotumor within the popliteal fossa. Intraoperatively, a browny-grey, knotted and hard structure was to be seen, which histologically imposed as a hyalinated scar tissue with black particular deposits. Energy dispersive X-ray microanalysis showed a high level of titanium within the intra- and extracellular deposits. In differential diagnosis these findings were postulated as "metalloma" (titanoma). In cases of periprosthetic pseudotumors, particular those with implant failure, a iatrogenic-induced metalloma should be considered.

Magnetic resonance imaging and miniarthroscopy of metacarpophalangeal joints: sensitive detection of morphologic changes in rheumatoid arthritis

OBJECTIVE

To evaluate and characterize magnetic resonance imaging (MRI) findings in the metacarpophalangeal (MCP) joints of rheumatoid arthritis (RA) patients macroscopically, using miniarthroscopy (MA; needle arthroscopy).

METHODS

The second MCP joint of the dominant hand of 22 RA patients (13 with various RA activities/stages; 9 with early RA [< or = 1.5 years' duration]) was examined by MRI followed by MA. Findings were evaluated by standardized semiquantitative measures of synovial and bony pathologic changes of the MCP joint, and were compared with the clinical and conventional radiologic findings.

RESULTS

Erosions and pre-erosions were detected in 17 of 22 patients by MRI; 2 of the other 5 patients (all early RA) displayed bony changes on MA. All 10 joints with pre-erosions on MRI (grade I bony alterations on MRI) exhibited significant cartilaginous and bony pathology on MA. Synovial membrane pathology was detected in all but 1 patient by MRI and in all patients by MA, although findings of plain radiography were normal in 6 of the 22 patients and another 9 patients had a Larsen score of 1. Semiquantitative analysis of synovial findings of MRI revealed gadolinium diethylenetriaminepentaacetic acid enhancement as a significant marker of macroscopically varied synovial vascularity and hyperemia, both of which strongly correlated with clinical activity (as measured by the Disease Activity Score). The extent of synovitis/synovial proliferation shown by MA and MRI were significantly correlated with each other, but not with any other activity or damage parameter analyzed.

CONCLUSION

In RA, both MRI and MA findings support early detection and staging of synovial changes. Ongoing longitudinal studies are aimed at evaluating the value of synovial proliferation as visualized by both methods.

Clara-cell hyperplasia after quartz and coal-dust instillation in rat lung

Bronchiolo-alveolar hyperplasia of type II cells in rat lungs after particle exposure is a well-known preneoplastic lesion. The Clara cell, stem cell of the bronchiolar epithelium and the main carrier of cytochrome P-450 isoenzyme system in the lung, has barely been evaluated with regard to this effect. The aim of this study was to examine Clara-cell hyperplasia after particle exposure and to characterize cell proliferation and its normal function. Female Wistar rats were intratracheally instilled with coal dust samples of variable quartz content, quartz (DQ12), titanium dioxide, or saline solution containing 0.5% Tween 80. After 126-129 wk, all coal mine dust- and quartz-exposed animals developed Clara-cell hyperplasia: up to 0.48% of the total lung area, which was significantly increased compared to titanium dioxide (p <.05) and control (p <.03) animals. Proliferation and hyperplasia of bronchiolar Clara cells by coal dusts was independent of their quartz content. The lack of proliferating cell nuclear antigen staining in most of the hyperplastic Clara cells suggests that following damage of alveolar epithelial cells, Clara cells migrate in and remodulate the alveolar epithelium. After the migration they keep their function in the xenobiotic metabolism, as shown by expansion of CYP2E1 active Clara cells. The minor development of Clara-cell hyperplasia in titanium dioxide-treated rats indicates that this is not a general particle effect, and is possibly due to its lower toxicity to epithelial cells.

[Benign tenosynovial giant cell tumor in the region of the upper ankle joint. A rare differential diagnosis of a soft tissue tumor of the foot]

The giant cell synovioma is a benign neoplasia classically located in the fingers. It mostly rises from tendon sheaths, sometimes from the synovia. Other locations than the fingers are rare. Making a differential diagnosis to lipomas, gangliomas or even malignant soft tissue tumors can be very difficult especially in rare locations. We report the case of a 21 years old man suffering from a giant cell synovioma in the area of the right ankle joint. The clinical, radiological and patho-morphological findings are documented. The tumor was excised totally, other foci were not found. The problems of making the right diagnosis are described.

Miniarthroscopy of metacarpophalangeal joints in rheumatoid arthritis. Rating of diagnostic value in synovitis staging and efficiency of synovial biopsy

OBJECTIVE

To evaluate miniarthroscopy (MA) (needle arthroscopy) of involved joints in rheumatoid arthritis (RA) in the early detection and staging of synovitis and its application in visual guided synovial biopsies.

METHODS

1.0 and 1.9 mm (0 degree/30 degrees) arthroscopes were used in a 2 portal technique. MA performance was developed and evaluated first on hand cadavers (n = 20) and then transferred to metacarpophalangeal (MCP) joints under local anesthesia conditions. Joints of 20 patients with RA with different disease activity and duration were scoped and rated according to scores adapted from arthroscopy of other joints.

RESULTS

In 20/20 cases MA provided visualizing and magnification of intraarticular features of MCP joints in RA and allowed grading of synovial alterations, chondromalacia, and bony alterations. Synovial surface changes, thickness, and fibrosis were related to disease duration, as was damage to cartilage and bone. The degree of acute inflammatory reactions like vascularity and hyperemia varied independently of chronic changes; synovial proliferation was reflected to some extent by C-reactive protein. In 2 patients with early RA, synovitis criteria were found macroscopically and histologically. In 18/20 joints, biopsies were taken under visual control; in the other 2, progression of disease (Larsen score >3) limited arthroscopy to 1.0 scope imaging only. Sampling sizes were sufficient for histologic and molecular analysis.

CONCLUSION

The developed standardized procedure of MCP arthroscopy is minimally invasive, practicable, and well tolerated by patients, and may allow synovitis monitoring, staging, and biopsy in patients with early as well as chronic arthritis.

Time-course analysis of type II cell hyperplasia and alveolar bronchiolization in rats treated with different particulates

In this study, we compared the morphological reaction patterns in rat lungs following a single intratracheal instillation of 20 mg quartz, 20 mg coal mine dust (15.3% quartz), or 25 mg talc. Control animals received a single dose of 0.5 ml saline solution intratracheally. Investigations by light microscopy, morphometry, and DNA image cytometry were carried out 3, 6, 12, and 18 mo after dust administration. During the investigation period, we observed a temporary increase in the number, area, and proliferative activity of the type II cells, which differed in intensity among the three dusts. After 18 mo, however, type II cells in treated animals did not differ from control animals. On the other hand, the expansion of a multifocal alveolar bronchiolization as putative preneoplastic lesion had progressed enormously by the end of the test (1-3% of the investigated lung area). Consistent with this, the proliferative activity of the epithelial cells in terminal bronchi of the coal mine dust- and quartz-treated animals was enhanced by the end of the 18-mo investigation period, while the reaction to talc was minimal (0.2% of totally investigated lung area). Our data suggest that in bronchiolo-alveolar regions, especially in the epithelium of terminal bronchi, there is an overshoot regeneration after cell damage that leads to an alveolar bronchiolization.

[Local effects and changes in wound drainage in the free peritoneal cavity]

In a prospective randomised study 30 mongrel rabbits received two standard colon-resections. Three types of drains were tested: (latex-rubber-) Penrose-drains, rubbertube- and silicontube-drains, which were placed in the lower abdomen. As a closed drainage-system the extraperitoneal tip of the drain was placed in a closed subcutis-pocket. One of the two colon-anastomoses also was drained. The findings were recorded on the 7th postoperative day. A single mechanic alteration was found, an ulcer caused by a silicon-drain, that pushed against the abdominal wall. The other signs of mechanic irritation were microscopically unspecified inflammatory reactions to the foreign body drain. There was no ascending infection caused by the drain. All infections came from complications of the colon resections. In contrast to common opinions the drains in the lower abdomen showed no adhesions to the abdominal wall or organs. Only the entrance of the drain into the peritoneum and the cotton-gaze of Penrose-drains showed in nearly all cases adhesions. The large amount of adhesions to the anastomosis-drains came from complications of the colon-anastomoses. As a cause of material, rubber- and latex-rubber-drains showed large fibrin-clots on their surfaces. 7 days after the operation only about 20% of the drains had sufficient function. The rest was occluded by fibrin-clots in the lumen of the drain or the cotton-gaze. Over all there is no difference in changes and effects of the three different types of drains, but silicon as material showed advantages.

[Calcifying granulomatous peritendinitis after local dexamethasone treatment]

In this article we report on a 43-year-old man, who had been treated with two cortisone injections containing soja bean oil for epicondylitis humeri radialis. Four weeks after the second injection necrotized fat which had been extracted surgically was sent to us for histological examination. We could show a calcifying collagen fibre necrosis being cleared by a granulomatous reaction and resorbed by granulation tissue. The calcifying necrosis of collagen fibres might have been induced by soja bean oil which were used as carrier of the drug.

[Physiologic and pathologic patterns of reaction to silicone breast implants]

Local morphological reaction patterns on breast implants can be of high significance as possible starting point for controversely discussed systemic immune response triggered by silicon or silicone. Therefore, the collagenous capsules of 149 explanted mammoplasty prostheses were examined macroscopically, under a scanning electron microscope and light-microscopically using antibodies to the macrophage antigen CD68, vimentin, muscle actin, and the proliferation antigen MIB1, and were then correlated with anamnestic data (implanted type of prosthesis, indication for im- or explantation). According to our examinations, the in-vivo durability of the prostheses' shells is considerably decreasing with the expansion of their surfaces. Regardless of the type of the prostheses' surface regularly a chronic-proliferating inflammation pattern could be identified in the periprosthetic capsulectomy specimens starting with a synovial metaplasia of proliferating CD-68-negative and vimentin-positive mesenchymal cells in the area surrounding the implants and ending by its transformation into a stage of dense hyaline collagenous fibrous tissue after an advanced implantation period (> 2 years). By this, the texturing of the prosthesis surface modifies only the course, but not the quality of the chronically fibrosing inflammation. Bleeding of prosthesis as well as the incorporation of the polyurethane-foam coating of different prosthesis types into the periprosthetic breast capsule lead to a significant lymphoplasmacytic infiltration, partly with participation of local vessels as defined in a "silicone vasculitis". Morphological signs of an at least local immune response are detectable in 8.3% of the examined fibrotic capsules even without a morphologically identifiable foreign-body embedding. They can be possibly referred to- as well as the complete absence of hyaline collagenous fibrous tissue in 30% of the cases-a yet not causally clarified, inter-individually different susceptibility of the implant bearers. Only the systematic registration of the above-mentioned morphological reaction patterns in a "prosthesis-passport" together with the additional clinical observation of the patients can ensure in future the realistic estimation of potential health risks caused by silicone breast implants.

Fiber-specific molecular features of tumors induced in rat peritoneum

Molecular markers such as mutational spectra or mRNA expression patterns may give some indication of the mechanisms of carcinogenesis induced by fibers and other carcinogens. In our study, tumors were induced by application of crocidolite asbestos or benzo[a]pyrene (B[a]P) to rat peritoneum. DNA and RNA of these tumors were subjected to analysis of point mutations and to investigation of mRNA expression patterns. With both assays we found typical features depending on the type of carcinogen applied. The analysis of point mutations in the tumor suppressor gene p53 revealed mutations in the B[a]P-induced tumors. However, in the tumors induced by crocidolite asbestos that were of the same tumor type as those induced by B[a]P, mutations in p53 were not detectable. Every mutation detected on the DNA level causes an amino acid substitution within one of the functional domains of the tumor suppressor protein. Therefore, these mutations seem to be of biological relevance for tumor progression and indicate a difference in the carcinogenesis regarding the type of the carcinogenic substance. An additional specificity of crocidolite-induced tumors was detectable by analyzing the mRNA expression of the tumor suppressor gene WT1, which is known to be expressed in human mesothelial and mesothelioma cells. A relatively high amount of WT1 mRNA was measured by quantitative competitive reverse transcription-polymerase using RNA extracted from crocidolite-induced tumors. However, WT1 seems to be expressed on a rather low level in tumors induced by B[a]P.

P53 mutations in tumours induced by intraperitoneal injection of crocidolite asbestos and benzo[a]pyrene in rats

Mutation analysis of the tumour suppressor gene p53 in tumours induced in the peritoneal cavity of rats revealed differences in the mutational pattern with regard to the carcinogenic substances applied. In tumours induced by benzo[a]pyrene a considerable amount of p53 mutations resulting in an altered protein structure could be detected. For the development of these tumours an escape from the p53 mediated cell cycle control can be assumed. However, in tumours of the same tumour type induced by crocidolite asbestos no mutations could be observed. Since there were even no spontaneous p53 mutations detectable in this tumour group, it is obvious that in these tumours the escape from cell cycle control does not take place via inactivation of p53. Therefore, it is concluded that the molecular mechanisms of carcinogenesis and tumour development in this tumour type depend on the type of carcinogen applied.

Silicotic lymph node reactions in mice: genetic differences, correlation with macrophage markers, and independence from T lymphocytes

Quartz was injected into a hind food of BALB/c and DBA/2 mice and on days 40, 90, and 180 the progressive response ensuing in the draining popliteal lymph node (PLN) was investigated by histopathology and immunohistopathology. The area of silicotic nodules (ASN) was measured by morphometry, and, by this parameter, strain BALB/c proved to be a high responder to quartz, and strain DBA/2 a low responder, albeit both strains showed a similar degree of reactive lymphoid hyperplasia in the draining PLN. Both strains also showed a similar quartz content in the draining PLN but in BALB/c mice quartz particles were concentrated in the ASN, whereas in DBA/2 mice they were evenly dispersed over the PLN. Because the silicotic response of athymic BALB/c nu/nu mice was even stronger than that of euthymic BALB/c mice, T cells are not required for the development of silicotic nodules. This fits the notion that quartz is not an antigen and that high and low responder strains are MHC-identical. Because quartz-treated BALB/c, but not DBA/2 mice, showed a persistent expression of the macrophage differentiation markers MRP8 and MRP14, phenotypically the observed strain difference in silicotic responsiveness seems to be expressed at the level of macrophages.

Differential diagnosis of malignant tumours in the abdominal cavity of rats after intraperitoneal injection of crocidolite or benzo[a]pyrene

In our investigation (i.p. test), crocidolite and benzo[a]pyrene, both caused a progression from initially reactive, then autonomously transformed proliferation of myofibroblasts and undifferentiated mesenchymal cells to malignant, multidirectionally differentiated (desmin and ED-1 positive) fibro-histiocytic tumours. Immunohistochemically these tumours showed no morphological characteristics (for example co-expression of vimentin and keratin in spindle-shaped tumour cells) of human asbestos-associated malignant mesotheliomas. On the other hand many tumour cells induced by crocidolite and benzo[a]pyrene had an ultrastructural appearance resembling fibroblasts and myofibroblasts. These have been demonstrated in only a few desmoplastic and sarcomatous mesotheliomas in human beings. None of the tumours revealed the typical ultrastructural features of epitheloid or transitional mesotheliomas. Apparently, both carcinogenic substances induce the transformation of undifferentiated pluripotent mesenchymal cells in rat peritoneum, regardless of their localization in the submesothelial compartment or perivascular connective tissue (preferentially after crocidolite application) or in the connective tissue pseudocapsule of major benzo[a]pyrene containing beeswax/tricaprylin depots in the mesometrium and mesenterial fatty tissue. In this way asbestos fibres in this animal experiment do not seem to induce an arrest in differentiation of intermediate or immature mesothelial cells as supposed formerly, but rather affect undifferentiated mesenchyme cells and myofibroblasts. This is an explanation for the immunohistochemical expression of markers of muscular differentiation in these tumour cells, which is known to occur in human malignant fibro-histiocytic tumours. If supplementary immunohistochemical investigations with different keratin antibodies also fail to confirm the mesothelial differentiation of the tumours induced in our i.p. test, the decision to call them "mesotheliomas" should be reconsidered. Further immuno-transmission-electron microscopical investigations with intermediate filament or macrophage antibodies are needed to clarify whether the term malignant "fibrohistiocytic sarcoma", "mesenchymoma" or "mesothelioblastoma" would be more correct from the morphological point of view.

Insulitis and islet-cell antibody formation in rats with experimentally reduced beta-cell mass

We studied the effect of severe reduction of beta-cell mass by 90% pancreatectomy on the immune tolerance to the endocrine pancreas. Four months after subtotal pancreatectomy all LEW.Han rats had developed mononuclear infiltration of islets and 9 of 14 rats were positive for islet-cell antibodies. Electron microscopy revealed lymphocytic invasion of endocrine tissue, lysis of beta cells and phagocytotic macrophages. None of these changes were seen 2 weeks after 90% pancreatectomy or 4 months after 10% pancreatectomy. Weekly substitution of islet antigens in the form of a homogenate of 100 islets into 90% pancreatectomized LEW.Han rats almost completely prevented the development of insulitis and autoantibodies. The dependence of insulitis on T cells was shown when 90% pancreatectomy in LEW.rnu rats (i.e., the congenic athymic nude strain), did not result in islet infiltration. The exocrine tissue remained normal in all experimental groups. During the observation period insulitis was not associated with overt diabetes but was accompanied by substantial enlargement of islets and of beta-cell mass, as shown by morphometry. Suppression of islet inflammation by injection of islet antigens abolished beta-cell regeneration, despite continuing metabolic stress in rats with 90% pancreatectomy. The findings indicate induction of islet autoimmunity in response to 90% but not to 10% pancreatectomy. We conclude that severe reduction of the islet-antigen mass allows the development of T-cell-dependent islet autoimmunity which indicates a loss of immune tolerance. In addition, the data suggest the existence of islet-antigen autoreactive immune cells in rats not genetically predisposed to autoimmune diabetes. Finally, we conclude that selective beta-cell regeneration occurs in association with insulitis.

Muscarinic receptors in gastric mucosa are increased in peptic ulcer disease

Muscarinic receptors stimulate the secretion of acid pepsinogen and mucous in gastric mucosa. Whether muscarinic receptors are involved in the pathogenesis of benign gastric disease is unknown. Receptor changes in these conditions were therefore sought. An autoradiographic technique was developed to determine quantitatively muscarinic receptors in microtome sections of biopsy specimens obtained during gastroscopy. Muscarinic receptor density was mean (SEM) 18.4 (1.2) fmol/mg protein in the corpus and 8.9 (0.7) fmol/mg protein in the antrum (n = 53). Neither chronic nor active gastritis was associated with receptor changes in the antrum but chronic gastritis was associated with a receptor loss in the corpus. Patients with acute or recent duodenal or antral ulcers (n = 23) had significantly higher levels of muscarinic receptors in the corpus than controls (n = 25) (22.2 (1.5) v 16.9 (1.7) fmol/mg protein respectively (p < 0.025). These results suggest that muscarinic M3 receptor is overexpressed in duodenal ulcer disease and may play a part in its pathogenesis.

Pulmonary alveolar proteinosis in rats after administration of quartz: its possible role in morphogenesis of lung cancer

In rats, primary peripheral lung tumors composed predominantly of alveolar type II cells have been induced by inhalation of alpha quartz. In our retrospective study on proliferation markers we evaluated lung specimens of 140 Wistar rats from larger experiments, which had been exposed to Dörentrup quartz (DQ12) by inhalation (10 mg/m3, 56 Weeks, 5 days/week, 7 h/day: n = 27) or intratracheal instillations (5 mg: n = 38; 20 mg: n = 10; 50 mg: n = 28; 15 x 3 mg: n = 12). In the last group 8/12 animals developed lung tumors. Animals were sacrificed 1-32 months after administration. For identification of an increased proliferation of alveolar type II cells the DNA content was monitored by microscopic (static) cytophotometry in histological slides. The argyrophil (AgNOR) method for the demonstration of nucleolar organizer regions (NOR) was used as second marker of type II cell proliferation. Measurements made 24 months after inhalation of DQ12 showed a slight increase of pneumocytic proliferation with 1.64 +/- 0.14 AgNOR/nucleus compared to the controls (1.23 +/- 0.04 mean AgNOR/nucleus). After intratracheal instillation of DQ12 a significant increase of AgNOR was found, e.g. 5 mg: 1.93 +/- 0.23 AgNOR/nucleus (6 months) and 1.96 +/- 0.19 (12 months); 50 mg: 1.77 +/- 15 (6 months) and 2.18 +/- 0.05 (12 months); 15 x 3 mg (+2 ml 2% polyvinylpyridine N-oxide s.c.): 1.81 +/- 0.13 AgNOR/nucleus (27-32 months). With the aid of the 2 c deviation index, i.e. the mean square deviation from the diploid DNA value, it was possible also to identify the pathologically increased proliferation of type II cells after intratracheal instillation of quartz: 0.02 +/- 0.01-0.06 +/- 0.04 c2 (controls); 0.07 +/- 0.04 c2 (5 mg/12 months); 0.12 +/- 0.08 c2 (15 x 3 mg/>27 months) and 0.68 +/- 0.48 c2 (50 mg/12 months). Only in the last group were nearly triploid values detected. Summarizing our results, intratracheal instillation and inhalation of quartz in rats regularly induces alveolar proteinosis and interstitial fibrosis in combination with a dose- and time-dependent increase of the type II cell proliferation rate. As mitogenesis increases carcinogenesis, alveolar proteinosis with increased pneumocytic proliferative activity might be a prerequisite for enhanced tumor development.

Basement membrane proteins in synovial membrane: distribution in rheumatoid arthritis and synthesis by fibroblast-like cells

Rheumatoid arthritis is a complex disease of unknown origin. In consequence of some immunological reactions, proliferative invading synovial tissue leads to destruction of normal joint architecture. The aim of this study was to investigate qualitative changes in extracellular matrix distribution of proliferating rheumatoid synovium and their cellular origin. Synovial tissues from 57 clinically indicated arthrotomies were investigated with immunofluorescence, using specific antibodies against extracellular matrix proteins in tissue slides and cultured cells, which were also studied for collagen biosynthesis. Results indicated that synovial fibroblast-like cells synthesize and secrete basement membrane proteins laminin and collagen type IV as e.g. endothelial cells or organogenic fibroblasts. Laminin and collagen type IV were specifically demonstrated pericellularly in the hyperplastic lining layer of active rheumatoid synovitis. These findings are discussed with respect to the possible implication of altered cell-matrix interactions in rheumatoid synovial proliferation.

Prevention of high- and low-dose STZ-induced diabetes with D-glucose and 5-thio-D-glucose

To induce hyperglycemia in mice by administration of STZ, two experimental protocols that involve different pathogenic pathways are being used. First, the intraperitoneal injection of a single high dose (HD-STZ) exerts direct toxicity on beta-cells, which results in necrosis within 48-72 h and overt permanent hyperglycemia. Second, injections of multiple low doses of STZ (LD-STZ), administered intraperitoneally on 5 consecutive days, induce both beta-cytotoxic effects and STZ-specific T-cell-dependent immune reactions. In LD-STZ models, only a combination of toxic and immunological effects result in gradually increasing hyperglycemia, provided male mice of susceptible strains are being used. In this study, we found that 5-T-G, a glucose analogue that has sulfur for oxygen in the pyranose ring, prevented, in a dose-dependent way, both HD-STZ- and LD-STZ-induced hyperglycemia and that D-G, which was only tested in the LD-STZ system, was also protective, albeit somewhat less so than 5-T-G. This protective effect was achieved by intraperitoneally injecting 5-T-G and D-G, respectively, right before each STZ injection. Protection against hyperglycemia was already achieved with a total of 3 injections of 5-T-G, 1 injection each given before the first 3 of 5 LD-STZ injections. By means of OGTT, it was determined that pretreatment with 5-T-G afforded protection from substantial beta-cell damage in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructure of mesothelial regeneration after intraperitoneal injection of asbestos fibres on rat omentum

In order to describe the ultrastructural features of the early phases of regenerating mesothelium in rat peritoneum, 69 cases were examined after intraperitoneal injection of 0.05-15 mg crocidolite, chrysotile B and other mineral and synthetic fibers. The findings show the presence of intermediate or transition cells between proliferating submesothelial connective tissue cells bearing the ultrastructural phenotype of myofibroblasts and mature fully regenerated mesothelium. Our results and data accumulated in the literature provide strong support for the hypothesis of submesothelial cells origin for regenerating mesothelium.

[Significance of sonography of the breast for surgical treatment of breast cancer]

In a prospective study of 119 patients with breast carcinoma the value of ultrasonography for surgical therapy was compared with the value of clinical results and mammography. The tumor localization (in 96.8%) and the exact preoperative staging following the pTNM-system (tumor size in 85.8%, lymph node involvement in 77.2%) were better predicted by ultrasonography than by mammography and clinical examination. Especially the multicentric-multifocal carcinomas (20 of 29 cases) were better detected. Preoperative ultrasonography especially improves planning a conservative management of breast cancer.

Mesothelial proliferation due to asbestos and man-made fibres. Experimental studies on rat omentum

The intraperitoneal test in rats has proven to be an appropriate method controlling fibrogenicity and carcinogenicity of asbestos fibres and other fibrous dusts. We analyzed the reaction patterns of mesothelial cover layer to different natural mineral fibres (crocidolite, chrysotile, actinolite, erionite, wollastonite) and man-made mineral and synthetic fibres (glass fibres 104/475, polypropylene, aramide fibres). The injection of doses between 0.01 and 100 mg dust suspended in saline solution led to a continued repairing proliferation of submesothelial connective tissue cells and focal submesothelial fibrosis. These changes were never observed after application of granular dusts as mine dust and quartz. After 15 to 28 months we often found an association of fibrosis and local reactive hyperplasia of partly atypical proliferation of rat omentum mesothelium. These changes were also demonstrated in cases without macroscopically visible tumors. In later stages the underlying fibrosis was often infiltrated and dissolved by mesotheliomas.

[Primary and secondary chest wall tumors from the pathologist's viewpoint]

Fibrous dysplasia (20%), metastases (16%) and chondrosarcoma (11%) are the most common bone tumors of the chest wall. Except lipoma, primary lesions of the soft tissue of the chest occur rarely as well. The Askin- and Abrikosoff tumor, elastofibroma dorsi and desmoid can be seen as typical exceptions. With respect to the histogenetic classification of undifferentiated sarcomas and thoracic metastases (f.e. prostatic carcinomas or mesotheliomas) an intimate cooperation of surgeons and pathologists as well as modern immunohistochemical investigations are required.

Asbestos induced fibrosis in the omentum of rats. Immunofluorescence microscopical demonstration of collagens types I and III; laminin and fibronectin

Fibrosis and neoplasia are evoked by asbestos fibres. Different experimental models have been used to elucidate the cellular mechanism of their pathogenesis but there is no report available dealing with the role of structural glycoproteins and collagens in the development of the fibrosis. The omentums of 20 female SPF-Sprague-Dawley rats were investigated 1, 2 and 6 months after intraperitoneal injection of 15 mg UICC reference samples of crocidolite, by light- and immunofluorescence microscopy. Using monospecific antibodies, laminin, collagens types I and III and fibronectin were localized. After 6 months typical asbestos bodies were detected. By indirect marking of the basal lamina with anti-laminin-antibodies the marked degree of vessel proliferation occurring during the development of granuloma became visible. The deposition of connective tissue which was already established after 4 weeks was mainly due to collagen type III. After 4 and 8 weeks an accumulation of fibronectin associated with larger asbestos fibres was observed. The results suggest that fibrogenesis is promoted by the opsonic activity of fibronectin for long asbestos fibres. The fibrosis may derive from activated resident fibroblasts.

[Decision aids in determining therapy of breast cancer by preoperative staging using sonography and computerized tomography]

In a prospective study the preoperative ultrasonography of 54 cases of carcinoma of the breast was able to predict the pTNM staging precisely in 83.3% for tumor size and in 72.3% for lymphnode metastases. Multicentric-multifocal carcinomas were diagnosed by ultrasonography in 10 of 13 patients, better than by mammography (6 of 13). The CAT scan is indicated only in advanced tumor stages. The preoperative staging by ultrasonography enables with more precision planning and differentiated therapy of the carcinoma of the breast, especially in view of breast-preserving therapy.

Effects of trilostane in normotensive and hypertensive rats

The effect of trilostane, a competitive inhibitor of 3 beta-hydroxysteroid dehydrogenase, on adrenal tissue and blood pressure was studied in normotensive and spontaneously hypertensive rats. The drug was administered orally in doses of 10, 200 and 650 mg/kg/day for 2 and 4 weeks. Trilostane induced an increase in adrenal weight by lipoid transformation of the zona fasciculata. Simultaneously a reduction of retroperitoneal fat tissue was seen in all animals. A significant increase in blood pressure was observed under a trilostane medication of 650 mg/kg/day in normotensive as well as in spontaneously hypertensive rats. Blood pressure under lower doses did not increase significantly. Both increase of blood pressure and reduction of retroperitoneal fat tissue might be caused by increased release and synthesis of catecholamines.

Role of kidney and adrenals in the humoral pathogenesis of primary hypertension

In 18 spontaneously hypertensive rats (SHR) of the Münster strain the circulation was connected to that of normotensive animals using the carotid arteries and external jugular veins. The circulations were mixed by a peristaltic pump. In this model the normotensive rats were made hypertensive after a 10-min cross-perfusion cross unidentified humoral factors causing vasoconstriction play an essential role for the development of hypertension in SHRs.

Scintigraphic localization of phaeochromocytomas

131I-meta-iodobenzylguanidine scanning was performed in 14 patients with phaeochromocytomas. In all but one patient scintigraphy successfully localized the lesion(s). The results confirm that scintigraphic imaging with 131I-meta-iodo-benzylguanidine, a noninvasive method, is a valid and reliable procedure for imaging and localization of adrenal and extra-adrenal phaeochromocytomas, both benign and malignant.

[Radiological behaviour patterns of bone tumours (author's transl)]

The radiograph is usually the first step in diagnosis of tumorous bone lesions. Although definitive diagnosis depends on biopsy in many instances the radiograph allows the most essential decision on malignancy or benignity. This radiological grading of neoplastic bone disease is based on various criteria in particular the pattern of bone destruction and behaviour of the cortex. 3 main types of bone destruction predicting tumour behaviour can be differentiated: 1. the geographic well-defined destruction which is characteristic of static or slowly growing lesions; 2. moth-eaten pattern with scattered and confluent holes reflecting a highly aggressive lesion; 3. most aggressive permeative pattern characterized by multiple tiny holes. The cortex also reflects the response of normal bone against destruction. Depending on the activity of the process, the cortex will either remain intact, or will be expanded, or is even penetrated. The characteristic features of the different destruction patterns are illustrated by radiographs and corresponding pathologico-anatomical slices.

[Computer tomographic localisation in primary aldosteronism. Comparison with adrenal scintigraphy (author's transl)]

13 patients with verified primary aldosteronism (unilateral adrenal adenoma = 10, bilateral idiopathic hyperplasia = 3) underwent examination by CT and 131J-cholesterol-scintigraphy. CT-scan can successfully employed for localization of unilateral adenoma exceeding 10 mm in diameter. Small lesions and hyperplasia are rare CT-findings. The value of 131J-cholesterol-scintigraphy for differentiation of the two main subgroups of primary aldosteronism--adenoma and hyperplasia--is limited. In our experience both non-invasive methods are helpful to avoid misleading interpretation. In controversial cases bilateral adrenal venous blood sampling by catheterization is mandatory.

Dendriform pulmonary ossification

Four cases of dendriform pulmonary ossification are reported from postmortem roentgenography of isolated lungs. All showed pathoanatomical evidence of chronic fibrosing, mostly interstitial, rarely intraalveolar pneumonia, besides the typical manifestations of dendriform pulmonary ossification. Microscopy revealed fluid transition from proliferating, interstitially increased connective tissue to fully developed osseous structures. These dendriform structures can be seen in some analogy to the structural pattern of interstitial, bronchovascular as well as septal connective tissue; however, actual topographical correlation between bone structures and blood or lymph vessels could not be safely determined. Our observations suggest that dendriform pulmonary ossification may be interpreted as a rare complication, or special manifestation, of chronic fibrosing interstitial inflammation of the lung.