Search PubMed⌕ Search

Biomedical subjects

D Schreiber

Publications and source records attributed to D Schreiber.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Ultrastructure of the distal ureter in congenital malformations in childhood].

Ultramicroscopical examinations were performed in ten children with reflux or obstructive megaureter. Resected parts of ureters were used for investigation in connection with reconstructive procedures. Whereas in case of an obstructive megaureter an intramural and juxtavesical localised functionless narrow ureteral segment is characterised by "nexus close contacts" and dissociation of muscle cells with interposition of fibrous tissue, progredient pathonexual changes in the sense of a reversible nexus-distension and irreversible nexus-rupture were seen in megaureters with reflux. Dissociation of muscle cells is combined with typical epithelial and adventitial pathological structures. In congenital megaureter, disturbances in the electric syncytium occur in connection with nexus injury, followed by pathological innervation. Interruption of muscle autonomy and innervation in the wall structure of such congenital ureteral malformations play an ominous role in the sequence of pathogenetic factors.

Child↗
PubMed1987

High local carcinogenic activity of 1,3-dimethyl-3-phenyl-1-nitrosourea and its inactivation by intravenous application in rats: comparison of in vivo findings with the in vitro direct and a combined in vivo/in vitro sister chromatid exchange assay in V79-E cells.

1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) is a very potent local carcinogen in rats and induces a 100% frequency of forestomach carcinomas when applied i.g. in two different dosages (10 applications of 0.3 or 0.03 mmol/kg body wt, respectively, at 14-day intervals), but it is inactive upon i.v. administration (10 applications of 0.03 mmol/kg body wt at 14-day intervals). By means of the direct sister chromatid exchange (SCE) assay in V79-E cells in the presence of rat blood, serum or plasma, respectively, as well as by a 'host-mediated' SCE assay (in which the agent was given i.v. to rats, and blood taken from the animal was checked for the recovery of genotoxic activity in cell cultures), we tried to elucidate the unexpected lack of carcinogenic activity of i.v. DMPNU. The direct SCE assay revealed a drastic reduction of DMPNU genotoxicity by rat blood, serum or plasma, respectively, which is abolished by the esterase inhibitor diisopropylfluorophosphate. In the 'host-mediated' SCE assay a genotoxic activity of DMPNU was only recoverable after a very high i.v. dose and when the blood added to the cell cultures had been taken from the rat heart within 1 min after DMPNU administration in vivo. 1-Methyl-1-nitrosourea (MNU) and 1-methyl-3-phenyl-1-nitrosourea (MPNU) were used as positive controls in these experiments and also gave a lower response than theoretically expected, but the relative loss of activity with the latter compounds was much lower than with DMPNU. It is assumed that an esterase in rat blood effectively decomposes this trisubstituted nitrosourea. Problems of the novel 'host-mediated' SCE assay are discussed.

Animals↗
PubMed1987

Hepatic metabolism and secretion of a cholesterol-enriched lipoprotein fraction.

A potentially important source of cholesterol secreted in bile is cholesterol-rich lipoproteins. However, the fate of the cholesterol carried in these lipoproteins after hepatic uptake has not been investigated. We harvested an apoE- and cholesterol-rich lipoprotein fraction (d 1.02-1.06 g/ml) from hypercholesterolemic rats and examined the acute effects of these lipoproteins on hepatic cholesterol metabolism, very low density lipoprotein (VLDL) secretion, and biliary lipid secretion. Administration of a lipoprotein bolus (20 mg of cholesterol) to rats resulted in a significant decrease in 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and a significant increase in acyl-coenzyme A:cholesterol acyltransferase activity over controls at 1 hr. Hepatic cholesteryl ester content increased 400% with no change in hepatic free cholesterol content or biliary cholesterol secretion. These cholesterol-rich lipoproteins delivered in the isolated perfused liver effected a fivefold increase in hepatic VLDL secretion with no change in composition. Therefore, cholesterol-rich lipoproteins do not acutely alter biliary cholesterol secretion. Rather, the majority of the cholesterol delivered to the liver in these lipoproteins is either esterified and stored as cholesteryl ester or resecreted as free and esterified cholesterol in hepatic VLDL.

Animals↗
PubMed1987

[Animal experiment studies of the effect of peracetic acid on bladder urothelium].

Animal experimenters investigations on the influence of various solutions of peracetic acid on the epithelium of the urinary bladder were carried out on rabbits. The results of the experiments showed that solutions of peracetic acid up to 0.01% are tolerated nearly without any reaction also under extreme experimental conditions. Higher concentrations of active substances lead to considerable changes of the epithelium of the urinary bladder in form of partly focal, partly diffuse haemorrhagic necrotizing urocystitides. No differences were the result when the commercial 40 percent peracetic acid Wofasteril and a 20 percent peracetic acid without admixture of a stabilizer as primary solution were used. The possible application of peracetic acid as antiseptic for the mucous membrane is discussed.

Acetates↗
PubMed1986

[Description of neurocutaneous melanoblastosis].

Description of a rare case of neurocutaneous Melanoblastosis. In a 25 year-old man there was an extraordinary massiveness of the tumor in the field of the cerebrospinal soft membranes. Tumor cells, relevant for diagnosis, from lumbal and suboccipital liquor could be shown. Nomenclature and pathogenesis of the disease are discussed.

Adult↗
PubMed1986

Carcinogenicity of 1-methyl-3(p-chlorophenyl)-1-nitrosourea and its 1-methyl trideuterated derivative in rats.

The carcinogenic activity of 1-methyl-3(p-chlorophenyl)-1-nitrosourea (Cl-MPNU) and its 1-methyl trideuterated analog (Cl-MPNU-d3) was compared by intragastric administration to hooded rats of equimolar doses of both compounds. A 100% frequency of forestomach tumors was observed in both groups. However, the mean latency period of the animals treated with Cl-MPNU-d3 was significantly longer (P less than 0.01). The results suggest the occurrence of a deuterium isotope effect in nitrosoureas but not as distinct as in nitrosamines.

Animals↗
PubMed1985

[Neoplastic meningosis in immature cell leukemias and malignant lymphomas].

162 patients with acute leukemias or malignant non-Hodgkin lymphomas were examined for meningeal and cerebral manifestations of their disease. A clinically manifest disease could be found in 13 patients, meningosis was additionally detected by autopsy in 32 patients. The highest frequency was found in acute lymphatic leukemia followed by lymphoblastic lymphomas and acute myeloic leukemias. Less frequently there was a meningeal involvement in low-grade malignant lymphomas which becomes clinically manifest only in some rare cases. In this respect, non-lymphoblastic, high grade-malignant lymphomas take an intermediate position. On principle, meningosis prophylaxis is imperative for acute lymphoblastic leukemias and advanced lymphoblastic lymphomas.

Autopsy↗
PubMed1985

[Diencephalic pilocytic astrocytoma with clinical onset in infancy. Biological behavior and pathomorphological findings in 11 children].

Pilocytic astrocytomas of the diencephalon with onset of signs and symptoms during the first year of life are reported in 7 boys and 5 girls. Failure to thrive was the initial manifestation in 5 infants. In 2 of them a Russel syndrome emerged. The growth rate of the tumors was slow. One child survived without treatment for 2.5 years. The survival time of the treated children ranged from 7 months to 6 years and 4 months. All children died. No obvious indications of neurofibromatosis were found. All tumors infiltrated and destroyed the hypothalamus. In addition, the tumor infiltrated the optic chiasm in 3 cases and extended into the optic nerves in 2 of them. Most of the astrocytomas were large. Their maximal diameter exceeded 10 cm in 2 children. All were pilocytic astrocytomas grade 1. The grade of malignancy was the same in recurrences as in the initial operative material. Rosenthal fibres were uncommon. It is concluded that diencephalic pilocytic astrocytomas biologically and morphologically resemble most of the pilocytic astrocytomas occurring in early life in other parts of the brain. There is, therefore, no justification for regarding them as a separate tumor entity.

Astrocytoma↗
PubMed1984

Primary central nervous system tumors in stillborns and infants. Epidemiological considerations.

An epidemiologic investigation of true neoplasms of the central nervous system in fetuses and infants in the German Democratic Republic (GDR) was undertaken. Since all fetal deaths and all deaths in the first year of life are subject to a full postmortem examination and since all cancer cases or deaths are reported to a central registry, the prerequisites for a valid assessment of the incidence of these tumors are present. During the years 1960-1979, 55 histopathologically verified tumors of the central nervous system were identified in the GDR, a frequency of approximately 1.1 per 100 000 births. Unexpectedly, medulloblastoma (13 cases) was the most frequent tumor type.

Brain Neoplasms↗
PubMed1984

[Virologico-serologic studies in patients with brain tumors].

The etiological role played by human pathogenic herpes viruses for diseases of the central nervous system has been verified (Herpes simplex virus, varicella zoster virus) or is being discussed (cytomegalo virus, Epstein-Barr virus). In this study, the significance of herpes virus infections for surgically treated cerebral tumour patients is examined. In a total of 30 patients with various cerebral tumours, infectious virus from cerebral tumour tissue could be isolated in none of the cases. The mean geometric antibody titres against herpes virus in the patients did not differ from those of comparable healthy controls. In patients with cerebral tumours, however, acute herpes virus infections were serologically identified with a significantly greater frequency than in the control group. They are mainly an expression of endogenous re-infections with these viruses which inhabit latently the human organism. Possible causes of the observed asymptomatically proceeding herpes virus reactivations are discussed.

Adult↗
PubMed1984

[Primary intracranial tumors as cause of death in the fetus and infant].

Clinical and pathomorphological findings in 2 stillborn and 15 lifeborn children with primary intracranial tumors are reported. All infants died within the first year of life and the tumors were confirmed histologically. In 6 children the tumors (3 intracranial teratomas, 1 glioblastoma, 1 hemangioblastoma, 1 choroid plexus papilloma) were present at birth. All 6 were born with pathologically enlarged heads. Another child exhibited symptoms of brain tumor at the age of three weeks. The tumor was probably present at birth as well. In the remaining infants the signs and symptoms of tumor development became evident some months after birth. These tumors might have occurred postnatally. In a girl aged 9 months, a nephroblastoma of the right kidney and a malignant cerebral tumor, probably a glioma, were present. An incidental coexistence of both tumors is considered, however, a common etiology cannot be excluded. 8 of the 17 intracranial tumors were supratentorially situated. This supports the view that the proportion of supratentorial tumors is higher in early life than in older children.

Adolescent↗
PubMed1984

[Malformations of the urogenital system in autopsy material of children].

As a result of the autopsy reports of the Pathological Institute of Mühlhausen in the twenty-year-period from 1960 to 1979 there were 6.4% (n = 293) malformations of the urogenital system among 4,561 autopsies of still-born and live-born children up to their 16th year of age. Besides anomalies of the genital system, anomalies of the lower urinary tract, cystic kidneys, anomalies of kidney forms and dystopia as well as kidney agenesis were most commonly observed. The malformations were classified and discussed according to nature, combinations and sex differences, importance for mortality as well as with respect to territorial and time distribution.

Abnormalities, Multiple↗
PubMed1984

[Abnormalities of the skeletal system in autopsied children].

As a result of the autopsy reports of the Pathological Institute of Mühlhausen in the twenty-year period from 1960 to 1979 there were 4.8% (n = 180) malformations of the skeletal system among 4,561 autopsies of still-born and live-born children up to their 16th year of age. Club-foot was the most frequent malformation followed, with decreasing frequency, by inborn anomalies of the spinal column, syndactylia and polvdactylia as well as dysmelia. The malformations were classified and discussed according to nature, combinations and sex differences as well as with respect to territorial and time distribution.

Adolescent↗
PubMed1984

[Abnormalities of the digestive system in autopsy material of children].

As a result of the autopsy reports of the Pathological Institute of M uhlhausen in a twenty-year-period from 1960 to 1979 there were 4.8 per cent (n = 219) malformations of the digestive tract among the 4,561 autopsies of stillborn children and live-born ones up to their 16th year of age. Lip, jaw and plate clefts, defects of diaphragm as well as oesophagus atresia and stenosis predominate among the various malformations. The malformations were classified and discussed according to nature, combinations, and sex differences as well as with respect to importance for mortality, territorial and time distribution.

Abnormalities, Multiple↗
PubMed1983

[Tumors of the central nervous system in biopsy and autopsy material. 7th communication: neurinomas and neurofibromatoses with CNS involvement].

In 1,491 autopsy cases with CNS tumors observed at the Pathological Institute of the Medical Academy of Erfurt in the period from 1953 to 1976 (54,946 autopsies) 72 cases (4.8%) with neurinomas were found. They comprise 67 solitary neurinomas, 1 bilateral acoustic neurinoma without other signs of neurofibromatosis, and 4 cases of neurofibromatosis with neurinomas of the CNS. Among the 68 cases with CNS neurinomas (neurofibromatoses excluded) 87% were acoustic neurinomas, 12% spinal tumors, and 1 case was located in the trigeminal nerve. In 60 (88%) of these 68 cases, the neurinoma was operated upon or clinically diagnosed, resp. The diameter of 18 (26%) neurinomas of the autopsy material was larger than 5 cm. Patients in the 6th decennium predominated in this series. The sex distribution revealed a preponderance of females over males (3:1). In 3 cases further CNS tumors (ependymoma, glioblastoma, meningioma) were found. Additionally, 3 cases had carcinomas of different localization (Table 5). Following tumors were seen in 9 cases of Morbus Recklinghausen with CNS involvement: 4 cases with multiple neurinomas, 3 meningiomas, 1 astrocytoma, 2 glioses and 1 angiomatous malformation (Table 6). Among 1,670 CNS tumors in biopsy material, 144 (8.6%) were neurinomas. 60% of them were located in the nervus acusticus, 40% spinally, mainly in the thoracic region. The 6th decennium was most affected, and females were more frequent than males (2:1) in our material. Nearly all CNS neurinomas were benign. Only 1 spinal tumors was classified as a malignant neurinoma. 2 of the 9 cases with Morbus Recklinghausen had malignant neurogenic tumors (neurofibrosarcomas).

Adolescent↗