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Biomedical subjects

A Willemse

Publications and source records attributed to A Willemse.

At least 19 recordsLinked to original sources

Wolf-Hirschhorn (4P-) syndrome in adults.

Wolf-Hirschhorn syndrome (WHS) or 4p-deletion syndrome has been extensively described in children. Knowledge on adult WHS patients is still limited due to the small number of published cases. We present 4 adults and review the literature. The phenotype of adult WHS is in general similar to that of childhood WHS. Growth retardation, microcephaly and mental retardation are the rule in both adults and children. Facial dysmorphism also remains similar. The main difference lies in the absence of serious internal (cardiac) abnormalities in adult WHS. Mental retardation ranges from moderate to severe. The nosological overlap between WHS and Pitt-Rogers-Danks syndrome (PRDS) is discussed. More extensive data on adult WHS are needed for appropriate counselling of families with affected young children.

Abnormalities, Multiple↗

Visceral-endoderm-like cell lines induce differentiation of murine P19 embryonal carcinoma cells.

When P19 embryonal carcinoma (EC) cells were cocultured with cells from one of several established visceral-endoderm-like cell lines, the EC cells were rapidly induced to aggregate and differentiate, into cell types including mesoderm-derived cardiac and skeletal muscle. Neither parietal-endoderm- nor mesoderm-like cell lines induced aggregation or differentiation of EC cells in coculture, although a cell line with both parietal and visceral endoderm characteristics induced aggregation but not differentiation. Also, without the feeder cells aggregates of P19 failed to differentiate, provided that serum in the culture medium had been previously passed over dextran-coated charcoal to remove lipophilic substances, which may include endogenous retinoids. All experiments were carried out using serum treated in this way. Taken together, the results demonstrated that aggregation was necessary, but not sufficient, to make P19 EC cells differentiate. Direct contact between the two cell types was not necessary, since even when separated by an agar layer in cocultures, aggregates of P19 still differentiated. Medium conditioned by cells of the END-2 line, a visceral-endoderm-like derivative of P19, was particularly potent in inducing endodermal and mesodermal differentiation of single P19 aggregates, confirming the involvement of a diffusible factor secreted specifically by visceral-endoderm-like cells in this process.

Animals↗

Investigations on the role of flea antigen in the pathogenesis of German shepherd dog pyoderma (GSP).

Skin reaction patterns to the intradermal injection of a whole-body flea extract were examined in five physically healthy dogs and in 24 dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 8, 24, 48 and 72 hours after the injection. In 10 out of 24 GSP dogs a positive skin reaction was observed macroscopically after 15 minutes. Delayed reactions at 24 or 48 hours were not observed. In the control group neither immediate nor delayed reactions were observed. The histopathologic skin changes were basically the same in both groups: an initial polymorphonuclear reaction followed by a mononuclear cell reaction. In the GSP dogs, however, these changes occurred earlier and were more prolonged than in the normal dogs. No flea-antigen-specific IgGd antibodies could be demonstrated by enzyme-linked immunosorbent assay. It is concluded that delayed type hypersensitivity to flea antigen does not play a role in the pathogenesis of GSP. Immediate type hypersensitivity may contribute to the disease in some cases.

Animals↗

Investigations on the role of staphylococci in the pathogenesis of German shepherd dog pyoderma (GSP).

Skin reaction patterns to intradermal injections of a Staphylococcus intermedius antigen were examined in physically healthy dogs and in dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 6, 8, 24, 48 and 72 hours after the injection. In both groups the skin histopathology revealed an aspecific inflammatory response of an early polymorphonuclear reaction, followed by a mononuclear cell reaction at 24 and 48 hours. It is concluded that hypersensitivity to staphylococcal antigens does not play a role in the pathogenesis of GSP.

Animals↗

German shepherd dog pyoderma: a genetic disorder.

In this study the pedigrees of 42 German Shepherd dogs with German Shepherd dog Pyoderma (GSP) were analysed. Parents, littermates and offspring of the affected dogs were traced and their owners were questioned on characteristic skin lesions. Evidence suggesting an autosomal recessive trait was found. Breeders are advised to exclude affected animals and their relatives from further breeding.

Animals↗

[Dermatophytoses in dogs and cats].

The clinical features of dermatophyte infections in dogs and cats are discussed. Diagnostics methods, therapy and clinical management are extensively described.

Animals↗

Immunologic aspects of German shepherd dog pyoderma (GSP).

In 21 dogs with clinical features of German Shepherd dog Pyoderma (GSP) parameters of the specific and aspecific immune system have been examined. Chemotaxis and killing capacities of neutrophilic leucocytes were undisturbed, whereas in skin biopsies no specific immunoglobulin or complement deposits were found with immunofluorescence. With double immunodiffusion, antibodies against Gram-positive bacteria were found. In a laser nephelometric assay significantly elevated levels of IgG, IgGab, IgGd, IgM and bacterial components, associated and non-associated with circulating immune complexes, were detected. However, no relation was found with the disease state. It is concluded that dogs with GSP are immunologically normal reactors. A bacterial hypersensitivity reaction is hypothesized as a possible initiating factor in the pathogenesis of GSP.

Animals↗

Antibodies to immunoglobulin-G in dog sera, synovial fluids and aqueous humor: a comparative study of rheumatoid factor assays, suitable for routine application.

The incidence of anti-IgG antibodies (rheumatoid factors, RF) in body fluids (sera, synovial fluids and aqueous humor) selected from 62 normal and 275 diseased dogs was studied. Fluids were assayed by canine versions of standard agglutinating and/or precipitating RF assays with routine application in human practice. The number of RF detected by dog IgG-coated particles was substantially higher by latex fixation test (LFT) than by modified Rose-Waaler (RW) test (61/144 vs. 14/144). This did not result from false positives by LFT since latex activity was completely inhibited by aggregated dog IgG. Some evidence is presented indicating that results obtained by standard RW in particular, but also those obtained by standard LFT, might be improved by modifying testing conditions currently used. Body fluids were further studied for the presence of precipitins to aggregated dog IgG in 0.6% agarose (gel precipitation test (GPT]. The frequency of RF was higher by GPT than by LFT, both in normal control fluids (for sera 26/52 vs. 19/52) and patient material (for sera 135/197 vs. 95/197). Thus, the canine RF appear to be a serum component with an unexpectedly high frequency in both normal and diseased dogs, but grossly underestimated by the recommended routine RF assays based on agglutination. The GPT, which combines a superior detection rate of theoretically also agglutinating RF with an inability to detect RF quantitatively, seems an ideal RF 'indicator' test to dictate improvements to the quantitative LFT/RW assays so as to facilitate RF detection at clinically relevant concentrations. Thus optimized, RW/LFT would provide the optimal detection apparatus for the ultimate isolation of the relevant 'RF' repertoire present, for comparative studies aimed ultimately at unraveling the etiopathogenesis of the 'real' RF.

Animals↗

Induction of non-IgE anaphylactic antibodies in dogs.

Dogs immunized with o-DNCP-BSA or eggs of Toxocara canis developed anaphylactic antibodies other than IgE. The antibodies were heat-resistant at 56 degrees C for 2 hours, not reduced by 2-mercaptoethanol and PCA and P-K reactivity was only observed at 3-4 h sensitized sites of recipient skin. High titres of antigen-specific IgGd were determined by means of an ELISA technique.

Anaphylaxis↗

Allergen specific IgGd antibodies in dogs with atopic dermatitis as determined by the enzyme linked immunosorbent assay (ELISA).

Allergen specific IgGd antibodies were detected by the enzyme linked immunosorbent assay (ELISA) in 89% of the 62 atopic dogs studied. Antibodies were found most frequently against house dust (47%), human dander (50%), grass pollens (58%) and spring tree pollens (43%). These antibodies were also found in 11 of 20 dogs with atopic symptoms but without immediate skin test reactivity to inhalant allergens. Agreement between the presence of skin reactivity and allergen specific IgGd titres ranged from one of 14 for cat dander to 22 of 34 for house dust. Among dogs with atopic symptoms but without skin test reactivity and specific IgGd titres to the respective allergens, the agreement varied between 28 of 54 for human dander and 67 of 68 for cat dander. In view of the value of the dog as an experimental model of atopic disease in man, further studies of the pathophysiological significance of IgGd antibodies are warranted. In addition, reconsideration of the diagnostic criteria for canine atopic dermatitis, as done by Hanifin & Rajka (1980) in man, seems indicated.

Allergens↗

Effect of hyposensitization on atopic dermatitis in dogs.

In a double-blind study, 51 dogs with clinically defined atopic dermatitis were injected with either alum-precipitated allergen solutions or a placebo. Comparing the treatment results of both groups on the basis of scores for clinical signs, a significant difference in clinical improvement was established in favor of the allergen-treated dogs (P less than 0.01). The proportional changes of scores for clinical signs in the allergen-treated group ranged between +27.3% and -100% (median, -61.5%) and in the placebo group between +36.4% and -100% (median, 0.0%) with respect to the initial scores. Immediate skin test reactivity disappeared only in the dogs with a good clinical response. Of 27 dogs treated with an allergen solution, 16 (59.3%) had an improvement of 51% or more. In the placebo group, 5 of 24 dogs (20.8%) reacted this way. There was total remission of the clinical signs in 9 and 4 dogs, respectively. In the dogs in which, after 9 months of hyposensitization, any improvement was observed, the chance for final improvement of more than 51% was calculated as 84%. Discriminant analysis revealed that evaluation of the effect of immunotherapy can be restricted to the 9-month follow-up examination.

Adjuvants, Immunologic↗

Canine atopic disease: investigations of eosinophils and the nasal mucosa.

Blood eosinophil counts were comparable in dogs with and without canine atopic disease. Eosinophils were not observed in the nasal smears of any of the dogs studied. Of 46 dogs with atopic disease, a significant increase (P less than 0.001) in nasal airway resistance was observed in 2 dogs after nasal provocation with nebulized allergens of grasses and in 1 dog after provocation with summer weed extracts.

Airway Resistance↗