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D Schreiber

Publications and source records attributed to D Schreiber.

At least 91 records · Page 5Linked to original sources
PubMed1979

Tumors of the rat kidney induced by nitrosourea compounds.

Apart from other lesions, 51 renal neoplasms were induced in rats by administration of methylethy-, dimethyl- and phenylmethylnitrosourea. 3 tumors originated from the renal pelvis and were classified as transitional cell papilloma (1) or transitional cell carcinoma (2). 48 neoplasms were considered as "mesenchymal tumors". These growths were regarded as rat kidney specific tumors. They display a wide spectrum of histological structures: spindle cells which are capable to differentiate into smooth muscle cells, fibroblasts, angioblasts, fat cells, and even into cartilage thus forming the typical microscopical features which are completed by the tendency of mesenchymal cells to swirl around preexisting renal tubules in several closely investing layers. As the cell of origin is not yet established the term "mesenchymal tumor" seems to be the most suitable one. There is no basis for classifying these tumor as nephroblastomas and the two entities should be strictly separated.

Animals↗
PubMed1979

[A mathematical model for the determination of loss of venous capacitance using impedance plethysmography].

The results of impedance plethysmographic examination were evaluated by a mathematical curve analysis. The magnitude of the exponential coefficient of the saturation and discharge function provides a highly accurate measure of the loss of functionality. The percentage change in the flow rate may be obtained by substitution of the exponential coefficients in a model formula.

Humans↗
PubMed1979

[On the conception of a reference center "malignant lymphomas" (author's transl)].

Conceptions and experiences in connection with the foundation of a reference center "Malignant Lymphomas" of the Society of Pathology of the German Democratic Republic are described. The different degrees in reliability of pathomorphological diagnosis in the field of malignant lymphomas as well as the methods of co-operation with the reference center are reported.

Germany, East↗
PubMed1979

[Primary malignant lymphomas of the central nervous system (author's transl)].

9 primary malignant lymphomas of the CNS were found at autopsies. The youngest patient was 4 months and the oldest 69 years of age. The lymphomas were classified in accordance with the Kiel classification. Most of them were immunoblastomas and immunocytomas. The neoplastic transformation seems to start in the adventitia of the blood vessels. From there the tumour cells invade the brain tissue and the meninges. A multifocal origin of primary lymphomas of the CNS has been seen in some cases. An isolated development of primary lymphomas of the spinal cord is not present in our material. The pathogenesis of the primary malignant lymphomas of the CNS is discussed.

Adult↗
PubMed1979

[Electronmicroscopic investigations of N. trigeminus of rats during the phase of tumour induction by ethylnitrosourea (author's transl)].

A single subcutaneous application of ENU to newborn rats causes after 2--4 days lethal and sublethal toxic lesions in some of the Schwann cells and their corresponding axons and myelin sheaths. The sublethally damaged Schwann cells show mainly alterations of myelin sheath formation. The ensuing regeneration produces between the 28.--35. day not only normal Schwann cells but also abnormal ones. These are characterized by atypical nuclei and a gradual loss of their functional relation to axons and are therefore regarded as Schwann cells in blastomatous transformation. The deviation from the normal of the NAD-linked L-alpha-glycerol-3-phosphate dehydrogenase caused by ENU correlates with the described morphological findings. Inspite of its partially unspecific character it may therefore be considered as an early indication of a beginning tumorous transformation.

Animals↗
PubMed1978

[Postnatal and transplacental carcinogenic effects of methyl methanesulphonate (MMS) and ethyl methanesulphonate (EMS) in hooded rats (author's transl)].

In the last years numerous investigations of the preferentially neurotropic carcinogenic action of different indirectly alkylating N-nitroso-compounds have been reported. Contrary to these the nuber of experiments, in which the effect of directly alkylating methyl methanesulphonate (MMS) and ethyl methanesulphonate (EMS) was studied is relatively small. Therefore, in own investigations on 4 groups of hooded rats of the inbred strain E the postnatal and prenatal effects of MMS and EMS were studied.

Age Factors↗
PubMed1978

[Isolated neoplastic foci in the central nervous system in generalized non-Hodgkin-lymphomas. A prospective pathomorphological study (author's transl)].

A comprehensive post-mortem investigation of the central nervous system (CNS) in 103 patients with malignant non-Hodgkin-lymphomas was performed. Neoplastic foci were revealed in the CNS in 21 cases. Five of them were visible at gross examination. Strong evidence exists that the incidence of the CNS-involvement is correlated with the lymphoma-type. Our cases were classified according to the Kiel-classification (Lennert 1975). The findings suggest that CNS-infiltrations are rather common in lymphoblastomas and immunocytomas whereas they seldom occur in plasmocytomas.

Adolescent↗
PubMed1978

[Morphology of heart tumors in rats induced by methyl- and ethylnitrosourea].

The results of morphological examinations of 78 heart tumors in BD IX rats induced by methyl- and ethylnitrosourea (MNU, ENU) administered by various routes are described. After repeated intravenous or intraperitoneal injections of MNU heart tumors developed in 39--46% of the treated animals. The following localizations were found: left ventricle--55, right ventricle--7, both ventricles--12, other sites--4. In 51 (65.4%) of 78 cases there were early stages of tumor with a ribbon-like lining of the affected ventricle wall. They consisted of elongated stream-like-arranged tumor cells. Large tumor nodules protruding into the ventricular lumen usually showed considerable features of cellular and nuclear polymorphism. The heart tumors were classified as fibromas or neurinoma-like tumors, fibrosarcomas, and polymorphous sarcomas. Histogenetically, the neoplastic cells are probably derived from fibroblasts and Schwann cells.

Animals↗
PubMed1978

[Combined transplacental carcinogenic action of N-nitrosomethylurea (NMU) and N-nitrosoethylurea (NEU) in rats].

To reveal the relationship between teratogenesis and carcinogenesis, the author studied brain blastomogenesis features against the background of the development of deformities induced by the combined transplacental effect of NMU and NEU. To induce brain defects such as microcephaly NMU was injected on the 15th day, whereas to induce cerebellar defects- on the 21st day of embryogenesis. Moreover, at the 13th or 17th day NEU was additionally injected, which is found to be highly effective for inducing brain tumors. It was found that in NMU exposure (at the 15th day) until NEU exposure (at the 17th day of embryogenesis) no reliable decrease in brain tumor occurrence was noted, compared with that if only NEU was employed. In the reverse sequence, i. e. first the exposure to NEU (at the 13th day) and then to NMU (at the 15th day) the occurrence of tumors located in cerebral hemisphers was 3 times less. It is assumed that cytotoxic effect of NMU leading to microcephaly is likely to cause the death of a considerable amount of cell population previously transformed.

Animals↗
PubMed1978

[Early stages of experimental brain tumours in rats. Investigation of serial sections (author's transl)].

The results of transplacental induction of brain tumours by a single intravenous injection of ethylnitrosourea in a dosage of 20 or 30 mg/kg body weight to pregnant BD IX and Albino rats on the 17th day of gestation are presented. From 46 animals of the offspring 43 rats developed 185 intracranial neoplams. 157 of them were early stages. Most of the animals had multiple tumours. One rat showed 13 separate tumour nodules. The average number of brain tumours was 4.3 per rat. 101 tumours had a diameter of less than 1 mm. The neoplasms were classified as 179 glial tumours (mainly polymorphous gliomas, oligodendroastrocytomas and oligodendrogliomas), 4 sarcomas and 2 gliosarcomas. All the oligodendrogliomas and about two thirds of the polymorphous gliomas were early stages. The following preferential localizations in the rat brain were established: White matter of cerebrum, hippocampus, basal ganglia, cortex of cerebrum and brain stem. 25.4% of the tumours were localized in the subependymal area. Bulbus and tractus olfactorius, leptomeninx, and cerebellum were very rare sites of tumour growth.

Animals↗
PubMed1977

[On the classification of experimental brain tumours (author's transl)].

UNLABELLED: The classification of experimental brain tumours is essential for mutual understanding and for comparison with human CNS tumours. The histogenetic principle of human neurooncology should be applied to the classification of experimental tumours, too. In rats different quantities of experimental tumours have been classified as ependymonas by various authors. The aim of our morphological investigation is to elucidate the reasons of the differences. The tumours were induced with ethyl- or methylnitrosourea in newborn or adult rats or by trnasplacentar application. Serial sections through the cerebrum of 57 rats were performed to detect early tumour stages and to study their localization within the brain. In other rats the brain and spinal cord were investigated in selected areas. RESULTS: 174 small tumours, most of them less than 2 mm in diameter were found. Early tumour stages never involved the ependyma of the ventricular walls or of the central canal of the spinal cord. These tumours exhibited a strong activity of acid phosphatase whereas the ependymal cells were inactive. No true rosettes, cilia or blepharoblasts were seen in the tumours. No perivascular zones, free of nuclei were found. In literature the experimental ependymomas have been diagnosed on grounds of row-like arrangements of tumour cells. We found similar peculiar structures in large experimental oligodendrogliomas and glioblastomas. Our findings suggest that the classification of experimental brain tumours as ependymomas is not justified in many of the cases published in literature. To avoid misinterpretation of experimental results in their significance for human neurooncology the criteria of the histogenetic classification should be applied thoroughly.

Animals↗
PubMed1977

[Ruptured intracranial aneurysms. Autopsy studies from two pathological institutes (author's transl)].

Among 67,930 autopsies 233 (0.3%) ruptured unoperated intracranial aneurysms were found. 105 aneurysms belonged to the anterior, 89 to the middle, and 29 to the posterior groups. The size, age and sex distribution of the aneurysms as well as the lesions due to their rupture were studied. The following complications were found (table 4): Massive subarachnoid haemorrhages (77%), intracerebral haematomas (61%), massive intraventricular haemorrhages (35%). Intracranial aneurysms were combined with polycystic degeneration of the kidneys in 8 patients. The pathomorphological findings were compared with the clinical diagnoses. The clinical diagnosis of a ruptured intracranial aneurysm was established in 13.9% of the patients only.

Adolescent↗
PubMed1977

[Functioning carcinoma of the exocrinic pancreas. Case report and review of the literature (author's transl)].

The rare case of a 62 years old male with functioning carcinoma of the exocrinic pancreas, liver metastases, and subcutaneous fat necrosis is described. Only 22 relating cases were found in the literature. Referring to published observations the symptomatology of these pancreatic tumours is analysed. The panniculitis which is part of the symptoms corresponds to the Weber-Christian disease or erythema nodosum. It is supposed that lipase-secreting carcinomas of the pancreas occur more frequently than hitherto believed.

Autopsy↗
PubMed1977

[Malignant tumours of the female sex organs in the autopsy material (author's transl)].

1209 malignant tumours of the female genital organs were revealed by post-mortem examinations at the Pathological Institute of the Martin-Luther-University, Halle (GDR), in the years 1961 to 1970. They constitute 28.6 per cent of a total of 4232 malignomas including leukemias and other systemic lymphoreticular diseases that were found in females of all age groups during this period. The genital tumours were analysed concerning the localization, age distribution, size, histological classification, invasion of adjacent organs, frequency of metastases, and recurrencies, 729 (= 60.3%) of the tumours originated from the uterus, 399 (= 33.0%) from the ovaries. 95.2 per cent of all tumours were carcinomas and 65.9 per cent developed metastases. The highest frequency of metastases has been found in ovarian tumours (= 89.5%). This was mainly due to the frequency of peritoneal carcinomatosis in patients suffering from these malignomas. It is remarkable that 19.5 per cent of the genital tumours were misdiagnosed by the clinicians.

Adolescent↗
PubMed1977

[Electron microscopic investigations on early stages of experimental heart tumours in rats (author's transl)].

The views on the histogenesis of experimental heart tumours in rats are controversal. Up to now electron microscopic investigations on early tumour stages are lacking. In this study ultrastructural findings of 4 early stages of heart neoplasms in the left ventricle of BD-IX rats are reported. Material and methods. BD-IX rats received repeated intravenous injections of methylnitrosourea in a dosage of 20 mg/kg body weight. After averagely 9 months the animals were killed by ether anesthesia. Sections of the heart were fixed in solution according to Karlsson and Schultz (1965). In order to discover early stages of tumours light microscopic examinations were carried out on heart sections. Afterwards the small tumour-containing tissue samples were postfixed in 1% OsO4, embedded in durcupan, and double contrasted with uranyl acetate and lead citrate. Results. Light microscopy (semithin sections): Beneath an endothelium-like cell layer an area of parallel to each other arranged spindle-shaped tumour cells with usually hyperchromatic nuclei was found. Some cells were larger and contained pale nuclei. Electron microscopy: The spindle-shaped neoplastic cells with irregular nuclei are loosely arranged. Most of the cells were surrounded by a basement membrane. In the extracellular space abundant thin cell processes and collagen fibers were demonstrable. The tumours contained characteristic bundles of cell processes as well as single processes which enveloped a virtual point of the space. Some large and widely undifferentiated tumour cells had stump-like thick processes. In the area of trabecular muscle neoplastic cells of an apparently mesenchymal origin were present. The ultrastructural findings are discussed regarding the histogenesis of the small heart tumours in the rats. They probably developed from neoplastic Schwann cells but an additional mesenchymal component seems to be engaged. Further studies are necessary to clarify the significance of both components and their relations in the experimental heart tumours.

Animals↗
PubMed1977

[Problem of the special pathology of brain tumors].

The post-mortem material of the Erfurt Pathological Institute covering the period from 1953 to 1975 included 1376 primary tumours of the central nervous system, which corresponds to 2.6 per cent of all autopsies and 9.6 per cent of the autospies for malignant tumours. Thus, tumours of the central nervous system show the same frequency as leukoses and lymphomas and tumours of the female genitals and range before the tumours of the colon. The age distribution confirms well known conditions, but shows as apecu liarity that in infancy cerebral tumours occur just as frequently as in childhood and that the frequency of the occurrence of meningiomas before and after the 60th year of life is practically the same; but after that time they are clinically diagnosed in a distinctly less frequent number. Wrong clinical diagnoses were made in 23.5 per cent of the observations. Finally, it is pointed out that the intraoperative picture of the tumours may be misleading and only histological examinations will be helpful.

Adolescent↗