Biomedical subjects

W Hermanns

Publications and source records attributed to W Hermanns.

At least 19 recordsLinked to original sources

PubMed2004

Use of endoscopy and renal biopsy for the diagnosis of kidney disease in free-living birds of prey and owls.

Eighty-nine free-living birds of prey and owls were examined and blood samples and radiographs were taken. In addition, 126 specimens of renal tissue were obtained without complications, with a mean postbiopsy haemorrhage time of 67 seconds. On average, the samples were 2.2 mm long, 1.3 mm wide and 1.0 mm deep and they all contained proximal and distal tubuli and from one to 89 glomeruli; 49 of them contained from one to four intralobular veins, and on average each sample contained 10.7 per cent air sac tissue; 113 of the 126 samples could be evaluated histologically.

Animals↗

PubMed2004

Comparative morphologic and immunohistochemical investigation of spontaneously occurring thymomas in a colony of European hamsters.

This study documents the characteristics of a large series of spontaneously occurring thymomas in a laboratory colony of European hamsters (Cricetus cricetus). Thymomas are rare organotypic neoplasms originating from the thymic epithelial compartment. Because the hamster thymomas largely resembled their human counterparts, the recent World Health Organization (WHO) classification of human thymic epithelial tumors was used. Forty hamsters of both sexes aged 3-29 months were examined macroscopically and histologically. In 22 (55%) of the 40 animals, necropsy revealed enormous whitish masses in the anterior mediastinum, with a diameter ranging from 0.5 to 4.5 cm and a lobulated structure. The anatomy of the thymus region was normal in the remaining 18 hamsters. Histologically, the tumors presented as thymuslike organoid structures with areas of medullary and cortical differentiation and a predominance of lymphoid cells. A network of epithelial cells in the cortical areas, demonstrated immunohistochemically with a cross-reactive antibody against pancytokeratin, supported the diagnosis of thymoma. Cortical lymphocytes showed positive staining with cross-reacting antibodies against CD3 and terminal deoxynucleotidyl transferase, characteristic of immature T cells. On the basis of these findings, the tumors were classified as B1 thymomas, in some cases with AB or B2 components, according to the new WHO classification for human thymic epithelial tumors.

Animals↗

PubMed2004

[Endoscopic, pathologic-anatomic and histologic findings in the bovine teat. 1. Changes in the area of the teat cistern in slaughtered cows].

In the present study 795 teats of slaughtered cows were examined endoscopically. Teats which showed lesions were examined histologically. Abnormalities were detected endoscopically in 37 teats. In five cases red discolorations were observed. Histologically these alterations proved to be fresh bleedings within the fibromuscular layer of the teat cistern. Thirteen teats showed yellowish discolorations of the cistern surface. Three of these cases could not be cleared up histologically. In the other cases moderate or severe blood pigment deposition (n = 10) or severe fibrosis (n = 3) of the fibromuscular layer were found. Neither fresh bleeding nor severe blood pigment deposition was found in teats with normal coloured epithelium of the cistern. Cistern surface was smooth in 18 cases, whereas in 19 cases nodules were found. Histologically all nodules consisted of fibrovascular tissue ("granulation tissue") covered with cisternal epithelium. Detailed histological examinations, however, revealed considerable morphological variations regarding the overlying epithelium, the extent and kind of cellular infiltration, the extent of angioplasia and fibroplasia as well as fresh bleedings or deposition of blood pigment in the underlying fibrovascular tissue in some cases. It was concluded, that teat endoscopy enables a differentiation between fresh and old bleedings according to the coloration of the cisternal surface. Nodular proliferations of the cistern surface generally consists of fibrovascular ("granulation") tissue. Further histological details, however, and thus possible information about the pathogenesis of the lesions cannot be assessed endoscopically.

Animals↗

PubMed2004

[Endoscopic, pathologic-anatomic and histologic findings in the bovine teat. 2. Changes in the area of Fürstenberg's rosette].

In the present study endoscopically diagnosed changes of the Fürstenberg's rosette were examined histologically. For this purpose the teats of 200 slaughtered cows were inspected. In 19 cases proliferations in the region of the Fürstenberg's rosette were found. Additionally, tissue samples were taken from the Fürstenberg's rosette of 26 cows which showed milk flow disorders due to stenoses of this part of the teat. Teats of slaughtered cows as well as biopsy specimens were fixed in 5% formaldehyde and embedded in paraffin and in plastic. All specimens were stained according to H.E., Giemsa and Turnbull, respectively. Histologically, the proliferations of the Fürstenberg's rosette consisted of fibrovascular tissue (granulation tissue) covered by keratinized squamous epithelium (teat canal epithelium) in eleven cases. In the other cases double-layered cuboid epithelium (cisternal epithelium) was found additionally. The formation of granulation tissue and deposition of blood pigment was observed exclusively in areas covered by stratified epithelium. Therefore a traumatic lesion of the teat canal was supposed to be the cause of the histological findings. In contrast to several reports in the literature, however, no indications of an inversion of the teat canal epithelium were found. On the basis of these findings, the hitherto assumed idea of pathogenesis of proliferations of the Fürstenberg's rosette was modified and a new pathogenesis pattern was developed.

Animals↗

PubMed2003

Histopathologic and immunophenotypic characterization of extramedullary plasmacytomas in nine cats.

To contribute to the existing body of knowledge in the literature on the apparently rare extramedullary plasmacytoma in cats, lymphoid tumors with plasmacytic cellular morphology taken from nine cats were examined. The paraffin-embedded material was investigated by standard hematoxylin and eosin, and special staining techniques (Giemsa, Congo-red, and periodic acid-Schiff reaction). The tumors also were examined immunohistochemically for the presence of immunoglobulin G, immunoglobulin A, immunoglobulin M, immunoglobulin light chains (lambda, kappa), various amyloid proteins, and FeLV-antigen (p27 protein). An immunoglobulin-producing tumor of plasmacellular origin (extramedullary plasmacytoma [EMP]) could be diagnosed in all cases on the basis of immunohistochemical light-chain expression. All but one of the neoplasms occurred in the skin of older, predominantly male cats. As in humans and dogs, the following types could be identified according to their morphologic features: mature type (two), cleaved type (two), asynchronous type (four), and polymorphous type (one). The tumor tissue of three cats revealed amyloid deposits, which were immunohistochemically diagnosed as ALlambda-amyloid in all three cases.

Animals↗

PubMed2003

[Acute herpesvirus-gastritis in a cat].

Gastritis in cats is caused, among other things, by infectious agents, like bacteria, metazoic parasites or viruses. Herpesvirus-gastritis has not as yet been documented in cats. Therefore in this paper such a case will be described. In this case the mucous membrane of the stomach shows multifocal acute necroses with evidence of intranuclear inclusion bodies in epithelial cells of the gastric glands. By means of electron microscopy the causative virus can be specified as herpesvirus.

Acute Disease↗

PubMed2003

[Enzootic calcinosis in sheep after consumption of golden oat grass (Trisetum flavescens L., P. B.)].

In 12 sheep (Coburger Fuchsschaf; 10 female, 1 male, 1 wether), grazing on a pasture with approximately 20 (to 40)% golden oat grass and fed the respective hay, clinical findings and outcome of Trisetum flavescens induced calcinosis were controlled for 2 1/2 years. Besides lameness typical for calcinosis (slightly bent carpus and relatively stretched position of tarsal and fetlock joints when standing, 'kneeling' on the carpi) the patients showed increasing impairment of the circulatory and respiratory systems (holosystolic endocardial murmur, congestion, exspiratory dyspnoea etc.). 4 of the 12 sheep died (2) or had to be euthanatized (2) because of peracute heart failure; 5 patients showing chronic circulatory insufficiency as well as 1 animal suffering from severe lameness had likewise to be euthanatized (Ubersicht 1-3). One calcinotic ewe (No. 12), still alive at the time of this evaluation (2003), gave birth to 2 healthy lambs and nursed them. The ram (No. 5) had to be eliminated for another disease. The mostly severe calcifications of the cardiac valves, the endocardium and the arterial vessels as observed during the pathomorphological examination are consistent with the clinically diagnosed cardiovascular insufficiency. Furthermore, calcification of several tendons and ligaments, the kidneys and in 3 cases of the pulmonary parenchyma could be found. Clinical observations and post mortem findings showed a remarkable individual variation. Compared to calcinosis in cattle, in sheep the functional disturbance of the circulatory system was striking.

Animal Feed↗

PubMed2002

Cutaneous chlorellosis in a gazelle (Gazella dorcas).

Cutaneous chlorellosis in a gazelle caused a chronic granulomatous inflammation in the subcutaneous tissue of the carpus. The diagnosis was based on the intense green color of the lesion and the presence of organisms identified as algae of the order Chlorellales. According to morphologic and ultrastructural features, the genus Bracteacoccus is most likely.

Animals↗

PubMed2001

Immunohistological demonstration of erythroid cells in canine bone marrow.

In an immunohistological/cytological study of canine bone marrow, the aim was to demonstrate canine erythroid cells with the help of various commercially available antibodies against human antigens (monoclonal antibody against glycophorin A, polyclonal antibodies against haemoglobin and spectrin). In order to preserve possible cross-reacting epitopes various fixation methods (cross-linking, precipitating and dehydrating fixing agents, partly in combination with unmasking measures), decalcification techniques [acid or ethylenediaminetetraacetic acid (EDTA) decalcification] and tissue-embedding methods (paraffin embedding, cryostat sectioning technique) were used. Alternative methods, such as the preparation of cell smears and immunoblotting, were also employed. The only result that was of use for routine diagnostic procedures (paraffin sections) was that obtained by using polyclonal antibodies against haemoglobin. Best results were achieved when tissue was fixed in a formaldehyde-glutaraldehyde mixture, decalcified in EDTA and treated with microwave irradiation. The primary antibody was used in a dilution of 1:500 and incubated for 16 h. With the exception of mature red blood cells and proerythroblasts, different stages of erythrocytopoietic cells in canine bone marrow were shown to be arranged in erythrons. The polyclonal antibody against spectrin also showed clear cross-reactivity, but was only employable in other systems (immunoblotting). The monoclonal antibody against glycophorin A reacted only when used on human tissue or cells.

Animals↗

PubMed2001

Zoonotic potential of Enterocytozoon bieneusi.

The reservoirs and the modes of transmission of the most frequent microsporidial species in humans, Enterocytozoon bieneusi, are still unknown. We have examined fecal samples of 26 humans and 350 animals from 37 species to find 18 samples containing this parasite from humans, cats, pigs, cattle, and a llama. Genotypic characterization of the internal transcribed spacer of the rRNA gene resulted in 14 different genotypes, 6 of them previously undescribed. Phylogenetic analysis revealed the lack of a transmission barrier between E. bieneusi from humans and animals (cats, pigs, and cattle). Thus, E. bieneusi appears to be a zoonotic pathogen.

Animal Diseases↗

PubMed2001

[Role of podocyte damage in the pathogenesis of glomerulosclerosis and tubulointerstitial lesions: findings in the growth hormone transgenic mouse model of progressive nephropathy].

The sequence of structural changes terminating in glomerulosclerosis, tubular atrophy and interstitial fibrosis was analyzed in the growth hormone (GH) transgenic mouse (TM) model of progressive renal disease. The investigation was performed in TM expressing the bovine GH gene under the control of the murine metallothionein-1-promoter and non-transgenic controls (CM) of different age groups. The kidneys were studied by light microscopy, transmission and scanning electron microscopy, and were analyzed with stereological methods. Early-stage renal lesions were characterized by glomerular hypertrophy and mesangial expansion. In 7-week-old TM the mean glomerular volume was twice that of age-matched CM. The number of endothelial and of mesangial cells per glomerulus was increased in TM vs. CM, while the number of podocytes did not change. The podocytes demonstrated hypertrophy and foot process effacement. Concomitant with an age-related further increase of glomerular size in TM, severe maladaptive podocyte lesions including detachment of podocytes were observed. The resultant denudation of the glomerular basement membrane was associated with severe proteinuria, glomerular hyalinosis, synechia formation and collapse of glomerular capillaries. These lesions progressed to glomerular obsolescence that was associated with atrophy of the adjacent tubule and interstitial fibrosis. The progressive kidney lesions in this model appear to be attributable to a considerable extent to podocyte damage resulting from the limited capacity of this cell type to keep up with progressing overall tuft growth. The findings provide further evidence that mature podocytes are unable for effective cell replication in vivo, and that podocyte damage plays a significant role in the pathogenesis of progressive glomerulosclerosis with tubular atrophy and interstitial fibrosis.

Animals↗

PubMed2000

[Vitamin D3 poisoning--case report].

Over 650 pigs died within a couple hours in a fattening unit with approximately 3,000 fattening spaces. The pigs showed vomiting, dyspnea, kyphosis, sunken flanks, diarrhea, and polyuria. Another striking symptom of the pigs, besides the apathy, was the aphonia, due to the calcification of the vocal cords. An acute vitamin D3-intoxication was found to be the cause. The pathologic findings, especially the histologic detection of calcification processes of the soft tissues, lead to the suspect of an intoxication with a vitamin D-like substance. Between 39,000 and 196,000 IU/kg of vitamin D3 have been detected in a ready-to-use food mix. 8.8 million IU/kg of crystaline vitamin D3 were found in an open whey bag. An explanation how vitamin D came into the bag could not be clarified to this point.

Animal Feed↗

PubMed1999

Equine glanders in Turkey.

In the course of an epidemiological study of glanders on a number of Turkish islands in the Sea of Marmara, 1128 horses were examined by using the intracutaneous mallein test. Thirty-five (3-1 per cent) developed an increase in rectal temperature and a swelling at the point of injection. Ten of these horses were killed and glanders was confirmed in five cases by the presence of lesions and by the immunohistological demonstration of the causative agent, Burkholderia mallei. Clinical and pathological findings indicated that in all cases the infection was restricted to the mucous membrane of the nasal cavity with its parasinus, the nostrils and the upper lips. It was confirmed that equine glanders is endemic in Turkey.

Animals↗

PubMed1999

Overgrowth of skin in growth hormone transgenic mice depends on the presence of male gonads.

Growth hormone has been shown to possess stimulatory effects on various connective tissues. We observed that skin growth in male rat phosphoenolpyruvate carboxykinase-bovine growth hormone transgenic mice (serum growth hormone levels: 740-1940 ng per ml) is progressive with age, resulting in an "oversized coat" phenotype with a marked increase in absolute and relative skin weight and surface area, and in thickness of the dermis. Histologic changes include severe dermal fibrosis and replacement of subdermal adipose tissue by fibrous tissue. Apart from an increase in skin surface area, these changes were not noted in female transgenic mice, arguing for a specific interaction of growth hormone with male sex hormones. To clarify this point, 6 wk old male transgenic mice and control mice were castrated and compared with their noncastrated counterparts in parameters of skin growth at an age of 8 mo. The skin weight of castrated transgenic mice was smaller (p < 0.01) than that of intact transgenic mice both absolutely and relative to body weight. The relative skin weight of castrated transgenic mice was in the same range as in intact and castrated control mice. Absolute and relative skin area of castrated transgenic mice was greater (p < 0. 001 and p < 0.05) than in controls but lower than in intact transgenic mice (p < 0.001 and p < 0.05). When compared with control mice, intact transgenic mice displayed an increase (p < 0.01) in the thickness of dermis. In castrated transgenic mice the thickness of the dermis was in the same range as in control mice. Our findings demonstrate a specific interaction of growth hormone with male sex hormones resulting in a marked stimulation of skin growth.

Androgens↗

PubMed1999

Myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML) and chronic myeloproliferative disorder (CMPD) in cats.

Histological, enzyme histochemical and ultrastructural findings in three cases of feline bone marrow neoplasia are described. The following changes were observed: in myelodysplastic syndrome (MDS), a low medullary blast count, strongly atypical (micromegakaryocytic) proliferative megakaryocytopoiesis, hypoplastic erythrocytopoiesis with impairment of differentiation, multifocal extravasation and lymphoid aggregates; in acute myeloid leukaemia (AML), medullary proliferation of undifferentiated cell types; in chronic myeloIproliferative disorder (CMPD), trilinear medullary proliferation with complete cellular maturation, osteomyelosclerosis and extramedullary haemopoiesis. In two cases (MDS, AML), ultrastructural demonstration of C-type virus particles (feline leukaemia virus) suggested a viral aetiology.

Acute Disease↗

PubMed1999

Prognostic value of histopathological grading in canine extramedullary plasmacytomas.

The canine extramedullary plasmacytoma (cEMP) has recently been the subject of numerous investigations, indicating that the histomorphologic diagnosis is often difficult because of the variety of morphologic features. Therefore, the objective of this study was to establish a subclassification scheme for cEMPs and to evaluate correlations between the types and malignancy. Retrospectively, 117 cEMPs, all immunohistochemically characterized by a monoclonal immunoglobulin light-chain expression, were collected and assigned to morphologic types. These types were compared using data from a follow-up study on metastasis and tumor recurrence, then compared by proliferation rate, determined by immunohistochemical detection of the antigen Ki-67. Histopathologic typing revealed five different types of cEMPs, ranging from the mature type with typical plasma cells to the polymorphous-blastic type. Between these two forms, three additional types were established: hyaline, cleaved, and asynchronous. Most of the cEMPs were of the cleaved and asynchronous types. In all cEMPs, mononuclear and multinuclear giant cells were present to varying degrees. Although the results of cell proliferation and the follow-up study indicated less benign behavior by the polymorphous-blastic type, the proliferation rate revealed no statistically significant differences among the cEMP types. The clinical data therefore confirmed previous findings that the risk of tumor recurrence and metastasis in general can be classed as low. The established cEMP typing system is probably a very helpful diagnostic tool, although the types cannot be used for a tumor grading system.

Animals↗

PubMed1998

Effect of chronic GH overproduction on cardiac ANP expression and circulating ANP levels.

Sodium and water retention are common in acromegaly and upon GH administration. The underlying mechanisms, however, have not been clearly characterized as yet. Therefore, the aim of this study was to examine possible alterations of atrial natriuretic peptide (ANP), an endogenous regulator of volume homeostasis, in response to chronic elevated GH. We used GH-transgenic mice (GH-TM) as a model for chronic hypersomatotropinemia and moreover investigated 7 and 27 week old animals, respectively, in order to discriminate between short and long term effects of GH overexpression. Hematocrit values were reduced in GH-TM compared to control animals and it is known that plasma volume is increased in these animals. Structural lesions of the kidney were found in the GH-TM, however, in the animals studied there were no signs of renal insufficiency as evidenced by serum creatinine and urea levels. The serum concentration of immunoreactive ANP (IR-ANP) determined by RIA was significantly (P < 0.005) elevated in the young GH-TM as compared to control littermates (81.7+/-13.3 vs. 50.9+/-10.8 fmol/ml). The increase in serum IR-ANP of 27 week old GH-TM, however did not reach the level of significance (57.13+/-16.3 vs. 50.25+/-16.4 fmol/ml). Serum samples of control mice as well as of the 7 week old animals mainly contained ANP 99-126, known to be the circulating form of ANP. In contrast, serum of 27 week old GH-TM predominantly showed the cardiac storage form of ANP, ANP 1-126. Cardiac expression of ANP was quantified by Northern blot analysis. mRNA coding for ANP was found 1.2- and 2-fold increased in the atria of 7 and 27 week old GH-TM, respectively. In parallel, a 2.2-fold (7 week) and 2-fold (27 week) increase of IR-ANP was observed in transgenic atria compared to tissue of control animals. In contrast, no significant difference of ANP mRNA expression or of content of IR-ANP was observed in the ventricles of both groups of animals. In conclusion, GH-TM show various alterations in their ANP status suggesting an influence of the peptide on the effect of GH in fluid retention.

Aging↗

PubMed1998

Intestinal dimensions of mice divergently selected for body weight.

BACKGROUND: Selection for body weight provides important animal models for studying mechanisms of growth regulation. This study evaluated growth responses of the gastrointestinal tract (GIT) to long-term selection of mice for high (H line) or low (L line) 8-week body weight as compared with random-bred controls (C line). METHODS: Weights and dimensions of the various parts of the GIT were recorded from 8-month-old mice. For light microscopic stereological analyses, samples were taken from eight equidistant locations covering the whole jejunum/ileum. Vertical sections were used for estimation of fractional volumes of mucosa, submucosa, and muscularis and of villous surface area density and for measurement of villus length. RESULTS: Differences between groups in weights and dimensions of the various parts of the GIT were more pronounced in the proximal than in the distal segments, with greatest values in H, followed by C and L mice. Relative to body weight, intestinal growth was similar in the three lines, except for significantly (P < 0.001) increased relative weights of jejunum/ ileum, caecum, and colon in L mice. The fractional volume of mucosa and villus length decreased, whereas the fractional volumes of submucosa and muscularis increased from the proximal to the distal locations. The absolute volume of mucosa was greatest in H mice, followed by C and L mice. Relative to body weight, the volume of mucosa was significantly (P < 0.01) greater in L mice than in the two other lines. The mean total villous surface area of jejunum/ileum was significantly (P < 0.01) different among the three lines (L line: 144 cm2; C line: 227 cm2; H line: 304 cm2) but proportionate to differences in metabolic body weight. CONCLUSIONS: Selection for body weight affected various parts of the GIT to a different extent. The parameters investigated changed markedly along the small intestine, demonstrating the need for systematic sampling. Vertical section stereology provides unbiased estimates of total villous surface area, which is a parameter of major biological significance.

Animals↗