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Biomedical subjects

W Baumgärtner

Publications and source records attributed to W Baumgärtner.

At least 91 records · Page 5Linked to original sources
PubMed1992

Effects of humoral hypercalcemia of malignancy on the parathyroid gland in nude mice.

The ultrastructure of parathyroid chief cells was examined from four groups of nude mice (NIH:Swiss) with different serum calcium concentrations. The groups consisted of eight male mice with hypercalcemia induced by transplantable canine adenocarcinoma (CAC-8), eight female mice with hypercalcemia induced by infusion of parathyroid hormone-related protein, ten male control mice, and six male mice fed a low calcium (0.01%) diet. Hypercalcemia induced by malignancy or parathyroid hormone-related protein infusion was associated with low serum phosphorus concentration, a decrease in the number of secretory and prosecretory granules in the parathyroid chief cells, and an increase in the cytoplasmic area of chief cells. Prominent myelinlike membranous whorls were present in the cytoplasm of chief cells of tumor-bearing and parathyroid hormone-related protein-infused hypercalcemic mice. Mice fed a low calcium diet had decreases in the number of secretory granules and cell area but increases in the number of prosecretory granules compared with control mice. The number of mitochondria and the nuclear area of chief cells were similar in all four groups. The prominent membranous whorls and increased cytoplasmic area of chief cells from these hypercalcemic mice mark these cells as distinctly different from the parathyroid chief cells of other species with hypercalcemia.

Adenocarcinoma↗
PubMed1991

Intranasal infection of ferrets (Mustela putorius furo) with canine parainfluenza virus.

Immunocompetent and cyclophosphamide-immunosuppressed ferrets were intranasally infected with canine parainfluenza virus (CPIV) and observed for clinical signs, histopathologic lesions, the immunocytochemical demonstration of CPIV antigen in the respiratory tract and scanning electron microscopic alterations of the tracheal epithelium until 36 days post infection (p.i.). In both groups, clinical signs were minimal, restricted to the upper respiratory tract and consisted of cough elicited by tracheal compression between 3 and 7 days p.i. Microscopically, inflammatory and degenerative lesions were observed in the trachea and less frequently in the nasal cavity; bronchiolitis or interstitial pneumonia was not demonstrated. By immunocytochemistry, CPIV antigen was demonstrated in tracheal epithelial cells, whereas nasal cavity, bronchi, bronchioles and lung were devoid of viral antigen. Ferrets given CPIV alone developed a minimal lymphocytic tracheitis with minimal loss of cilia and CPIV antigen was observed only 4 days p.i. 17 days p.i., normal epithelial organization and ciliary reappearance was reestablished. Ferrets treated with cyclophosphamide and infected with CPIV exhibited mild to moderate histological lesions as above with similar scanning electron microscopic changes until 36 p.i. Tracheal lesions consisted of intraepithelial and submucosal infiltration of lymphocytes and macrophages, focal epithelial hyperplasia and multifocal loss of cilia. In addition, mild and transient neutrophilic infiltration was observed. In immunosuppressed ferrets, viral antigen expression was prominent and demonstrated 4 and 8 days p.i. These data suggest that ferrets are susceptible to aerosol CPIV infection.

Animals↗
PubMed1991

In vitro cytopathogenicity and in vivo virulence of two strains of canine parainfluenza virus.

In vivo and in vitro properties of two strains of canine parainfluenza virus (CPIV) were investigated. One strain, designated CPIV(+), induced syncytial giant cell formation and cytolysis in vitro, whereas the second strain, CPIV(-), caused only a mild strand-forming cytopathic effect with few, small syncytial giant cells. Vero cells infected with CPIV(+) or CPIV(-) were 100% positive for CPIV antigen as determined by immunofluorescent staining; however, 100% of CPIV(+) and less than 10% of CPIV(-) infected cells were hemadsorption positive. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis revealed no differences in electrophoretic mobility of viral polypeptides between both strains; however, in CPIV(-), reduced or absent synthesis of the putative HN and F1 proteins was observed. Isopycnic separation of CPIV(+) progeny virions showed a high proportion of viral particles with a buoyant density of 1.18 g/cm3. In contrast, CPIV(-) progeny virions had a heterogeneous density profile ranging from 1.08 to 1.18 g/cm3. Intracerebral infection of six ferrets with CPIV(+) resulted in moderate lymphocytic and histiocytic choroiditis, meningitis, and ependymitis, whereas CPIV(-) infection caused only mild to moderate inflammation. Immunohistologically, CPIV antigen was prominent in ependymal lining cells of the ventricles in CPIV(+)-infected ferrets and was reduced or lacking in CPIV(-)-infected ferrets (n = 6). Sham-injected ferrets (n = 6) did not have histologic lesions and no viral antigen was identified. The present findings suggest that certain changes in the activities of CPIV glycoproteins may lead to alterations of CPIV virulence in vivo.

Animals↗
PubMed1990

Vaccine-associated canine distemper infection in a litter of African hunting dogs (Lycaon pictus).

Four, 57 days old, African hunting dog puppies (Lycaon pictus) from one litter died within three weeks following vaccination with modified-live canine distemper virus (CDV) and killed canine adenovirus type 1, canine parvovirus and Leptospira icterohemorrhagiae and canicola. 18 days post vaccination, the animals developed neurologic disease characterized by episodes of grand mal seizures and circling. Macroscopic, histological and immunohistochemical studies revealed acute systemic CDV infection with acute encephalopathy. Virus isolation attempts using primary dog kidney cells, lung macrophages and Vero cells were negative. Therefore, the question whether the infection was the result of vaccination or natural infection remains open. The benefits and risks regarding the use of modified-live CDV vaccines and killed canine distemper vaccines in exotic carnivores are briefly discussed.

Animals↗
PubMed1990

Immunocytochemical demonstration of proopiomelanocortin-derived peptides in pituitary adenomas of the pars intermedia in horses.

Adenomas of the pars intermedia from 19 horses and normal pituitary glands from seven horses were evaluated histologically and immunocytochemically for adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-endorphin (beta-END), proopiomelanocortin (POMC), prolactin, neuron specific enolase, and glial fibrillary acidic protein (GFAP). The 26 horses ranged in age from 7 to 31 years. Histologically, all adenomas had a uniform pattern characterized by cords of large columnar cells forming palisades and pseudoacini separated by a delicate fibrovascular stroma. Immunostaining of adenomas derived from the pars intermedia was similar to that of non-neoplastic equine pars intermedia. An immunocytochemical evaluation revealed a diffuse, strong cytoplasmic reaction for POMC, a moderate to strong reaction for alpha-MSH and beta-END, a weak reaction for ACTH, and negative immunostaining for prolactin, GFAP, and neuron specific enolase in the adenomas. The unique clinicopathologic syndrome that develops in horses with pituitary adenomas appears to be the result of an over-production of POMC-derived peptides in addition to space-occupying effects resulting in dysfunction of the hypothalamus and neurohypophysis.

Adenoma↗
PubMed1990

Neuroaxonal dystrophy associated with vitamin E deficiency in two Haflinger horses.

Neuroaxonal dystrophy and minimal diffuse degenerative myelopathy was diagnosed in two female full sibling, 1- and 2-year-old, Haflinger horses. Both animals developed slowly progressive ataxia from the age of 4 months. Clinical signs, which were more prominent in the hind legs, included hypermetria and dysmetria. Histological examination revealed neuroaxonal dystrophy characterized by spheroid formation, vacuolation, astrogliosis and lipofuscin pigment deposition in macrophages and neuronal perikarya. These changes were restricted to the gracilis and cuneate nuclei, nucleus of the solitary tract, nucleus intermediomedialis in the sacral and the seventh segment of the cervical spinal cord and Stilling-Clarke's column in both horses and the medial vestibular nucleus in the older horse. Both diseased Haflingers had significantly reduced serum alpha- and gamma-tocopherol values. No significant alteration in serum total lipid concentrations and serum selenium values were observed. It is likely that the condition has a familial hereditary basis. It is unclear whether there is a link between the observed neuroaxonal dystrophy and vitamin E deficiency and further investigations are warranted.

Animals↗
PubMed1989

Naturally occurring canine distemper virus encephalitis: distribution and expression of viral polypeptides in nervous tissues.

Formalin-fixed brain tissues from 16 dogs with naturally occurring canine distemper virus (CDV) infection were investigated immunohistochemically by a panel of eight monoclonal antibodies (mAb) directed against four structural CDV proteins. Three mAb recognizing different epitopes of the polymerase (P-1, P-2, P-3) protein, two clones identifying different epitopes on each, the nucleocapsid (NP-1, NP-2) and fusion (F-2, F-3) protein, and one mAb directed against the hemagglutinin (H-2) protein were used. The immunoreactivity of the clones was tested on formalin-fixed, paraffin-embedded Vero cells, which were lytically infected with the neurotropic R252 (R252-CDV) or the Onderstepoort (CDV/Ond) strain of CDV. Clones directed against the H-2 and F-3 epitope recognized CDV/Ond but not R252-CDV. The remaining six clones showed positive immunoreaction with both CDV strains. In vivo expression and distribution of the individual proteins and their epitopes varied substantially between animals and within lesions from the same animal. The NP-2 epitope showed positive immunostaining in all 16 cases. The P-2 epitope was demonstrated in 13, the NP-1 epitope in 12, the P-3 epitope in 9, and the P-1 epitope in 3 brains, but staining was severely reduced compared with the NP-2 epitope and restricted to areas with strong NP-2 expression. Immunostaining was prominent in early and subacute and reduced in chronic demyelinating lesions. mAb directed against the H and F protein showed no immunoreaction in diseased brains.

Animals↗
PubMed1989

Canine parainfluenza virus-induced encephalitis in ferrets.

Young seronegative ferrets were intracerebrally inoculated with a neurotropic strain of canine parainfluenza (CPI) virus and serially killed at intervals after infection for subsequent viral immuno-peroxidase, light microscopical and scanning electron microscopical evaluation. The CPI virus infection resulted in a self-limiting non-suppurative ependymitis and choroiditis with associated ependymal cell degeneration. These changes were accompanied by paraventricular and perivascular cellular infiltrates of lymphocytes and monocytes, predominantly in the fourth ventricle and the cervical spinal cord and less frequently in the lateral ventricles and Sylvian duct. The inflammatory lesions were first detected on post-inoculation day (PID) 8 and had largely resolved after PID 22. Two animals showed multifocal axonal degeneration in the mesencephalon and vestibular nucleus, respectively. Immuno-histocytochemistry showed that virus replication was restricted to ependymal and subependymal cells and was most prominent on PID 4. No prominent residual lesions were present in convalescent animals. Virus-neutralizing CPI antibodies developed by PID 9 and increased slowly thereafter.

Animals↗
PubMed1988

Evaluation of different fixatives and treatments for immunohistochemical demonstration of Coxiella burnetti in paraffin-embedded tissues.

Various fixatives and treatments such as acetone, methanol, Bouin fixative, modified Bouin fixative, 10% Formalin, modified methacarn, periodate-lysine-paraformaldehyde, acetone-methyl benzoate-xylene, and EDTA were evaluated for their effect on the immunoreactivity of Coxiella burnetii in paraffin-embedded tissues by using the avidin-biotin-peroxidase complex and the peroxidase-antiperoxidase procedure. C. burnetii antigen was shown to be present in liver, spleen, and uterus tissues of experimentally infected mice by all methods of fixation and treatment. A positive immunoreaction was seen in cytoplasmic vacuoles of macrophages, as extracellular rod-shaped organisms, and as residual particulate extra- and intracellular debris. Immunoreactivity and cellular preservation, however, varied substantially with the individual fixatives. Optimal immunostaining of C. burnetii was achieved by EDTA treatment and Bouin and acetone fixation. The avidin-biotin-peroxidase technique proved to be slightly more sensitive than the peroxidase-antiperoxidase procedure when primary antibody dilution was used as the criterion for sensitivity.

Animals↗
PubMed1988

Enzyme-linked immunosorbent fluorescence assay and high-pressure liquid chromatography for analysis of humoral immune responses to Coxiella burnetti proteins.

A microtiter enzyme-linked immunosorbent fluorescence assay based on alkaline phosphatase conjugate and 4-methylumbelliferyl phosphate as fluorogenic substrate was developed and adapted to quantitatively analyze immunoglobulin G subclass 1 (IgG1) and IgG2 responses of vaccinated and infected cattle to proteins of Coxiella burnetii. The enzyme-linked immunosorbent fluorescence assay surpassed the conventional enzyme-linked immunosorbent assay with a 50-fold-higher sensitivity and a broader range of linear dose-response signals. Antigens of C. burnetii were purified by sodium dodecyl sulfate extraction and molecular-sieve high-pressure liquid chromatography. The purified 14-, 27-, and 30-kilodalton proteins were used as antigens without any further treatment. Vaccination with either chloroform-methanol-extracted cell residues of C. burnetii or the 27-kilodalton major surface protein evoked an early IgG2 response to the 27-kilodalton protein (2 weeks after immunization), whereas IgG2 to lipopolysaccharides of C. burnetii was detected only in the late phase (13 weeks after immunization). These results may have implications for the serodiagnosis of acute and chronic Q fever. IgG1 against these antigens was induced solely by naturally occurring C. burnetii infections, indicating that infected cattle can be distinguished from vaccinated cattle by using the enzyme-linked immunosorbent fluorescence assay and SP27 antigen.

Animals↗
PubMed1988

Fixation procedures for retention of cellular morphologic features and for preservation of immunoreactivity of canine paramyxovirus antigens.

The effectiveness of 1% saponin at 55 C (SAP), glutaraldehyde-borohydride-saponin (GBS), and modified GBS (MGBS) as fixatives for preserving cellular morphologic features, as well as antigenicity of intracellular and membrane-bound viral proteins of canine parainfluenza virus (CPIV) and canine distemper virus (CDV) was studied. Use of the same fixatives for light and electron microscopic immunocytochemical examination also was investigated. By light microscopy, CDV inclusions were readily detected after SAP and MGBS fixation, but not after GBS fixation; CPIV inclusions were detected after GBS and MGBS fixation, but not after SAP fixation. Ultrastructurally, SAP-treated cells had moderate to severe cytoplasmic artifacts, although CDV-associated cytoplasmic and membrane viral antigens were readily labeled. The CPIV-infected cells contained only a few positively labeled membrane-associated antigens and cytoplasmic nucleocapsids (NC). Although GBS-treated cells had excellent ultrastructural preservation, immunolabeling was unsatisfactory; CPIV-NC were labeled incompletely, and CDV-NC were unlabeled. After fixation with MGBS, immunolabeling of NC and membrane-associated viral proteins for both viruses was achieved, and the architecture of infected cells was preserved.

Animals↗
PubMed1988

[Spinal lymphosarcoma in a foal].

The present report describes the clinical and pathological findings of a one year old foal presented with paralysis of the hind legs. Macroscopically and histologically, a lymphosarcoma in the vertebral body and the adjacent epidural space of T 16, in the spleen and the mesenterial lymph nodes was observed. The adjacent spinal cord showed focal degenerative changes characterized by dilatation of myelin sheaths, swollen axons and few macrophages.

Animals↗
PubMed1987

Evolution of in vitro persistence of two strains of canine parainfluenza virus. Brief report.

Lytic stock virus (CPI+) exhibited prominent CPE in Vero cell monolayers. The non-syncytial giant cell forming strain (CPI-) was isolated from brain tissues of a dog after experimental infection with syncytial giant cell-forming (CPI+) virus. In mixed infection experiments, CPI(-) virus interfered with the replication of CPI(+) virus in that simultaneously infected cells showed strand-forming CPE typical of CPI(-) and reduction of CPI(+) yield. The CPI(-) virus established immediate in vitro persistence, followed by a severe crisis at passage (p) 8 and several similar crises until p 31; no further crises occurred throughout the remaining observation period (p 80). The CPI(+) did not establish immediate in vitro viral persistence and experienced several lytic crises until p 29. No further crises were observed throughout the observation period (p 100).

Animals↗
PubMed1987

Persistent infection of Vero cells by paramyxoviruses. A morphological and immunoelectron microscopic investigation.

Two Vero cell lines persistently infected with canine distemper virus (CDV) or with both CDV and canine parainfluenza (CPI) viruses were investigated. Cells in the CPI-CDV cell line were 90-100% positive for CPI antigen and exhibited 10-80% CPI hemadsorption. Cytoplasmic CDV antigen expressed in both singly and dually infected monolayers varied weekly from 1 to 100%. Numerous cytolytic crises were observed in both cell lines. Cell replication was severely depressed in both cell lines when compared with uninfected Vero cells. Infrequent interfering activity against lytic CPI virus was present in the CPI-CDV cell line but not between lytic CDV and progeny virus from the CDV or the CPI-CDV cell line. Ultrastructurally, Vero cells persistently infected with both paramyxoviruses contained two types of viral nucleocapsids (NC). By immunoelectron microscopy, smooth NC were identified as CPI virus and rough NC were of CDV origin. The viral NC never intermingled but rather were restricted to discrete cytoplasmic areas containing either one type of NC or the other.

Animals↗
PubMed1987

Immunohistochemical demonstration of keratin in canine neuroepithelioma.

Morphological features and immunoreactivity for cytokeratin (CK), glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE) of three canine neuroepitheliomas and three canine ependymomas were investigated. Neuroepitheliomas were in three German shepherds as intradural-extramedullary solitary masses, with spinal cord displacement between T10 and L2. Histologically, they contained tubules and acini, lined by epithelial cells with focal squamous metaplasia, rosette-like structures, and polygonal to spindle-shaped cells between tubules. Acini were empty or filled with a homogeneous, eosinophilic periodic acid-Schiff (PAS)-positive material. Mitotic indices varied from low to moderate. Ependymomas occurred in the third (two cases) and fourth ventricle in adult boxers. Histologically, they were composed of cells with an ill-defined, scant amphophilic cytoplasm, with a central round euchromatic nucleus; cells formed pseudorosettes, with a central fibro-vascular stroma. Neuroepitheliomas stained for CK, but ependymomas did not. Both failed to stain for GFAP, NSE, or phosphotungstic acid hematoxylin (PTAH). Thus, antibodies to cytokeratin are useful to distinguish neuroepitheliomas from ependymomas.

Animals↗
PubMed1987

[Aplastic anemia in ferrets].

The present report describes both estrus associated and estrogen induced aplastic anemia in 7 female ferrets. The animals were presented with anemia, anorexia, apathy, melena and subcutaneous hemorrhages. Histologically, the animals showed panmyelophthisis and cystic endometrial hyperplasia.

Anemia, Aplastic↗
PubMed1986

A simple method for histochemical demonstration of viral inclusion bodies in cell monolayers in microtitration plates.

The present paper describes a Bouin's-formalin fixation and Giemsa staining procedure for demonstrating viral cytoplasmic inclusion bodies in cellular monolayers in microtitration plates. Monolayers are fixed in Bouin's fixative for 15 min followed by 10% neutral buffered formalin fixation overnight. After fixation, the monolayers are stained with 4% (v/v) Giemsa stain. The method is superior to the separate use of formalin, methanol or Bouin's fixation-staining methods and compares favorably to immunocytochemical techniques for sensitivity.

Cell Line↗