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Biomedical subjects

H Ernst

Publications and source records attributed to H Ernst.

At least 73 records · Page 4Linked to original sources
PubMed1993

Morphology and histogenesis of squamous cell metaplasia of the rat lung after chronic exposure to a pyrolized pitch condensate and/or carbon black, or to combinations of pyrolized pitch condensate, carbon black and irritant gases.

Female Wistar rats were exposed to different concentrations of a pyrolized pitch condensate and/or carbon black particles and/or a combination of irritant gases for 18 hours/day, 5 days/week for 10 months, followed by a clean air period of up to 20 months. Bronchiolo-alveolar hyperplasia and squamous metaplasia were important components of the resulting lesions. Squamous metaplasia and associated hyperplasia was investigated by routine histology, scanning and transmission electron microscopy, and by immunohistochemical detection of various cytokeratins (CKs). Intensely CK positive squamous metaplasia lacking a distinct stratum spinosum was distinguishable from squamous metaplasia with a distinct stratum spinosum that reacted weakly CK positive or CK negative. The CK positive type was histologically characterized by narrow intercellular spaces, the weakly CK positive or CK negative type had markedly enlarged intercellular spaces. Differentiated hyperplastic epithelium and the normal lung parenchyma reacted CK negative. In poorly differentiated hyperplasia of the alveolar type associated with squamous metaplasia scattered cells with characteristics of squamous differentiation were detected. Ultrastructurally these cells showed increased amounts of filament bundles and immunohistochemically a positive reaction with the CK antibody. These cells were regarded as precursor stages of squamous metaplasia of the lung periphery in rats.

Animals↗
PubMed1992

Atypical malignant mesotheliomas with osseous and cartilaginous differentiation after intraperitoneal injection of various types of mineral fibres in rats.

The histopathological appearance of malignant mesotheliomas with osseous and cartilaginous differentiation is described in detail. Bone and cartilage occurred in mixed and sarcomatoid mesotheliomas which were induced by intraperitoneal injection of various types of asbestos fibres (asbestos cement, crocidolite, UICC-amosite, UICC-chrysotile B, Calidria-chrysotile). Bone or cartilage were found in 32.7% of mixed mesothelioma and in 12.8% of sarcomatoid mesotheliomas.

Abdominal Neoplasms↗
PubMed1992

HLA and thyroid carcinoma.

HLA typing was performed in 40 thyroid carcinoma patients. No association was found between antigens of the HLA system and papillary, follicular or medullary thyroid carcinomas. Literature reports on different HLA associations are probably due more to the small number of cases in the studies involved than to ethnic or geographic differences.

Adenocarcinoma↗
PubMed1992

Osteochondroma in laboratory rats: a report of 3 cases in a Fischer-344, a Sprague-Dawley, and a Wistar rat.

Three cases of osteochondroma in a male Sprague-Dawley (SD) rat, a female Fischer (F344) rat, and a male Wistar rat are described. The rats were aged between 26 and 30 months. All osteochondromas were considered to be of spontaneous origin. The Wistar rat had multiple osteochondromas on both hind legs, the skull base, and a lumbar vertebra, whereas each of the F344 and SD rats was affected by a solitary osteochondroma, also on a lumbar vertebra. The lumbar osteochondromas were similar in appearance in all rats and consisted of a central core of trabecular bone, interspersed with fatty marrow and covered by a cap of hyaline cartilage. The additional tumors in the Wistar rat represented different developmental stages of osteochondroma with or without endochondral activity. The osteochondromas in the rats were morphologically similar to those described in humans and some domestic animal species.

Animals↗
PubMed1991

An autoradiography study of postoperatively labelled thyroid tissue and iodine storage.

Samples of fresh thyroid tissue obtained from 15 patients undergoing thyroid surgery were incubated with iodine 125 in culture solution to which thyroid-stimulating hormone (TSH) had been added and then examined by autoradiography. The radioactivity registered actively during the 90-min incubation period was primarily found in the lumina of follicles. Even morphologically similar follicles showed very heterogeneous uptake of radioiodine; small follicles often contained the highest concentrations of activity. The method applied appears to be particularly useful for answering the question as to whether and to what extent individual papillary or follicular thyroid carcinomas are able to store radioiodine. This information obtained immediately after surgery may contribute towards establishing the patient's prognosis and help in deciding on postoperative therapy and follow-up. Because of the heterogeneity of radioiodine uptake, it is mandatory to examine a representative sample of carcinoma tissue in order to obtain well-established results.

Autoradiography↗
PubMed1991

Pulmonary response to toner upon chronic inhalation exposure in rats.

A chronic inhalation study of a test toner was conducted by exposure of groups of F-344 rats for 6 hr/day, 5 days/week for 24 months. The test toner was a special Xerox 9000 type xerographic toner, enriched in respirable-sized particles compared to commercial toner, such that it was about 35% respirable according to the ACGIH criteria. The target test aerosol exposure concentrations were 0, 1.0 (low), 4.0 (medium), and 16.0 (high) mg/m3. Titanium dioxide (5 mg/m3) and crystalline silicon dioxide (1 mg/m3), used as negative and positive controls for fibrogenicity, were also evaluated. Inhalation of the test toner or the control materials showed no signs of overt toxicity. Body weight, clinical chemistry values, food consumption, and organ weights were normal in the toner- and TiO2-exposed groups, except for a 40% increase in lung weight in the toner high-exposure group. All of the changes in the toner-exposed groups were restricted to the lungs or associated lymph nodes. A chronic inflammatory response was evident from the bronchoalveolar lavage parameters for the toner high-exposure group. The incidence of primary lung tumors was comparable among the three toner-exposed groups and the TiO2-exposed, and air-only controls, as well as consistent with historical background levels. A mild to moderate degree of lung fibrosis was observed in 92% of the rats in the toner high-exposure group, and a minimal to mild degree of fibrosis was noted in 22% of the animals in the toner middle-exposure group. The pulmonary changes in the toner high-exposure group were smaller in magnitude than those found in the crystalline silica-exposed group. The comparative fibrogenic potency of TiO2, toner, and SiO2 was estimated to be 1:5:418 using a dosimetric model and assuming a common mechanistic basis. There were no pulmonary changes of any type at the toner low-exposure level, which is most relevant in regard to potential human exposures. The lung alterations in the toner high-exposure group are interpreted in terms of "lung overloading," a generic response of the respiratory system to saturation of its detoxification capacity. The maximum tolerated dose (MTD) criterion was met at the toner high (16 mg/m3)-exposure level.

Administration, Inhalation↗
PubMed1991

Colon adenocarcinomas in European hamsters after application of N-nitroso-bis 2-oxypropyl-amine.

In the European hamster (EH) weekly subcutaneous (s.c.) injections of N-nitrosobis-(2-oxypropyl)-amine (BOP) (LD50, males: 174 mg/kg, body weight (b.w.), females: 118 mg/kg b.w.) induced adenocarcinomas of the colon in 77% (1/10 LD50), 70% (1/20 LD50) and 87% (1/40 LD50) of the treated animals (combined incidence for both sexes (c.i.)). Cholangiocellular carcinomas, the second most common type of tumor were produced in a dose-dependent manner. Furthermore tumors were found in the respiratory tract, urinary tract the integumentum system and the exocrine pancreas. The presented data show a difference between the BOP-induced tumor spectrum in European hamsters and that of Syrian hamsters [5,8,11]. The high incidence of colon adenocarcinomas may provide a further model of colon carcinogenesis.

Adenocarcinoma↗
PubMed1991

Dormant metastases in medullary thyroid carcinoma. A case report.

Report on a patient in whom an extensively metastasizing medullary carcinoma of the thyroid was diagnosed at the age of 32 years. Noteworthy in her case history were watery diarrheas that had persisted for two years, suggesting that the medullary thyroid carcinoma had already existed for some time. Besides locoregional lymph node metastases, small foci of diffuse pulmonary metastases with lymphangitis carcinomatosa as well as osteoblastic skeletal metastases were present and intramammary metastases were detected later. The patient died from bilateral pleuropneumonia with empyema formation at the age of 47 years after an observation period of 15 years. During that period, no major changes in the pattern of metastatic spread were observed and one may therefore speak of "dormant" metastases in this case, although some manifestations showed increases and decreases in size.

Adult↗
PubMed1991

The myosin light chain enhancer and the skeletal actin promoter share a binding site for factors involved in muscle-specific gene expression.

The myosin light chain (MLC) 1/3 enhancer (MLC enhancer), identified at the 3' end of the skeletal MLC1/3 locus, contains a sequence motif that is homologous to a protein-binding site of the skeletal muscle alpha-actin promoter. Gel shift, competition, and footprint assays demonstrated that a CArG motif in the MLC enhancer binds the proteins MAPF1 and MAPF2, previously identified as factors interacting with the muscle regulatory element of the skeletal alpha-actin promoter. Transient transfection assays with constructs containing the chloramphenicol acetyltransferase reporter gene demonstrated that a 115-bp subfragment of the MLC enhancer is able to exert promoter activity when provided with a silent nonmuscle TATA box. A point mutation at the MAPF1/2-binding site interferes with factor binding and abolishes the promoter activity of the 115-bp fragment. The observation that an oligonucleotide encompassing the MAPF1/2 site of the MLC enhancer alone cannot serve as a promoter element suggests that additional factor-binding sites are necessary for this function. The finding that MAPF1 and MAPF2 recognize similar sequence motifs in two muscle genes, simultaneously activated during muscle differentiation, implies that these factors may have a role in coordinating the activation of contractile protein gene expression during myogenesis.

Actins↗
PubMed1991

Hyperthyroidism and thyroid carcinoma.

Twenty-two of 251 patients with differentiated thyroid carcinoma suffered from or had a history of hyperthyroidism. They were hyperthyroid with a diffuse goitre (N = 4), a diffuse goitre with a cold nodule (N = 10), a multinodular goitre (N = 6), and an autonomous adenoma (N = 2). Among the 22 patients, more than one fourth had an occult thyroid carcinoma with a diameter of 1 cm or less, those with the papillary tumour types, less frequently had lymph node metastases than the total group of patients with papillary carcinomas (13.3 vs 35.6%). The clinical courses of the 22 patients resembled those of the other thyroid carcinoma patients whose age and initial findings were comparable. In 643 patients who underwent surgery for hyperthyroidism the incidence of thyroid carcinoma was 2.3%. The increase in coincidence of hyperthyroidism and thyroid carcinoma repeatedly reported in recent years is probably ascribable primarily to extensive and improved diagnostics and not to a direct connection between hyperthyroidism and development of thyroid carcinoma. On the other hand, our findings do confirm that, even in the presence of hyperthyroidism, all thyroid nodules require careful diagnostics for exclusion of malignancy.

Adenocarcinoma↗
PubMed1991

[Which evidence permits a liver cell smear in cattle with metabolic disorders?].

The technique of liver puncture as described by Holtenius (1961) was assessed with regard to its practicability and safety in a preliminary study of 26 cattle and a follow-up study of 108 German black pied cattle. The sample material was smeared, stained and examined by light microscope. All animals with changes of grade 5 had to be slaughtered. Liver puncture is a simple, quick and safe technique which supplies useful information about the various stages of hepatic fatty degeneration in individual cattle.

Animals↗
PubMed1991

Osteoblastic bone metastases in medullary thyroid carcinoma.

We report on a 32-year-old medullary thyroid carcinoma patient with extensive metastases at the time of diagnosis. In contrast to the osteolytic metastases usually observed in thyroid carcinoma, the patient had osteoblastic bone metastases, assumed to be caused by biologically active tumor calcitonin. The patient died 15 years after initial diagnosis of the advanced tumor. The long survival time may indicate that the prognosis is better for osteoblastic metastases than for osteolytic metastases.

Adult↗