Heinz-Adolf Schoon

The impact of gelatin-resorcinol glue on aortic tissue: A histomorphologic evaluation

PURPOSE Although gelatin-resorcinol-formaldehyde glue has been used to treat acute aortic dissections for some time, concerns about formaldehydes mutagenicity and carcinogenicity made it imperative to develop a new glue compound. Gelatin-dialdehyde glue was produced by omitting the formaldehyde component and replacing it with two less toxic aldehydes, glutaraldehyde and glyoxal. This study evaluated the histomorphologic effects of the new glue through in vivo use on the aortic tissue of domestic pigs. METHODS Each animals infrarenal aorta was glued around an implanted prosthesis. Histomorphologic evaluation was performed after operation after 1 and 4 weeks. RESULTS The results demonstrated that the clinically observed tanning effect can be attributed primarily to the disintegration of the fiber texture, specifically collagenous, as well as smooth muscle fibers, and to the reciprocal alterations of the proteoglycan interstitial substance in the aortic wall. Macroscopic, microscopic, and electron microscopic analysis of the gluing process revealed an adequate healing process without any morphologically significant difference between formaldehyde and formaldehyde-free gelatin-resorcinol glue. CONCLUSIONS Gelatin-dialdehyde glue is able to produce the same effects in the area of the aortic wall as the substantially more toxic gelatin-resorcinol-formaldehyde glue and thus could be recommended for clinical trials for treating acute aortic dissections thus far yielding excellent initial results.

Formaldehyde-free collagen glue in experimental lung gluing

Because of the well-known limitations of the adhesive strength of fibrin glue, it is imperative to develop a stronger glue with acceptable biocompatibility. This was accomplished by removing the formaldehyde component from gelatin-resorcinol-formaldehyde glue and replacing it by two less toxic aldehydes--pentanedial and ethanedial. To evaluate the adhesive strength of this new glue, GR-DIAL, lung incisions in rabbit hybrids were glued together. Each group (n = 5) was examined histologically after 2 days and 1, 2, and 4 weeks. The glue disintegrated gradually with good bioresorption when the incision was closed with a thin layer of glue. The healing process was favorable, indicating good biocompatibility. Therefore, GR-DIAL glue is capable of enhancing the use of surgical glues in the field of thoracic surgery by enabling surgeons to close larger parenchymal lesions than with fibrin glue.

The equine endometrosis: New insights into the pathogenesis

This paper describes the histomorphological and immunohistochemical characterisation of phenotypic variations of endometrosis as well as potential etiological factors which may influence disease progression. In total, 779 endometrial biopsies were examined. These biopsies were taken in the breeding and non-breeding season (n=509), on defined days during the estrous cycle (n=70) and before and after experimentally induced bacterial endometritis (n=200). In addition to conventional histopathology, selected biopsies were investigated using alcianblue staining as well as immunohistochemical methods for the detection of steroid hormone receptors, Ki-67-antigen, vimentin, desmin, fibronectin, smooth-muscle-alpha-actin and laminin. The equine endometrosis can be divided into a destructive and a non-destructive form. Based on the morphology of the stromal cells involved, an active or inactive state can be distinguished in fibrotic foci. In all types of endometrosis, fibrotic stromal cells show a distinctly reduced expression of steroid hormone receptors in comparison to the intact stroma, indicating their dedifferentiation. However, the steroid hormone receptor expression of involved glandular epithelia seems to depend on the activity of the fibrosis. These results suggest an independency of all fibrotic foci from the hormonal control mechanism of the uterus. The characteristical features of destructive endometrosis are a large number of smooth-muscle-alpha-actin containing myofibroblasts, a pronounced epithelial vimentin expression, excessive extracellular matrix accumulation and a progressive alteration of the basal lamina. Furthermore, the frequently seen cystic glandular dilatation and mechanical destruction of the uterine glands may occur due to the contractibility of the myofibroblasts involved. As shown in this study, a simultaneous endometritis can cause a temporary activation of fibrotic stromal cells. However, cyclic and seasonal endocrine changes seem to have no effects on progression of the disease. It can be concluded that the various types of endometrosis represent different stages in the fibrotic process, possibly leading to the destruction of the glands and subsequently resulting in the development of a stromal fibrosis.

Immunohistochemical characterization of the extracellular matrix in normal mitral valves and in chronic valve disease (endocardiosis) in dogs.

This study aimed to characterize the composition and distribution of the extracellular matrix (ECM) components in normal canine mitral valves (MV) and in chronic heart valve disease (CVD). MV of 50 dogs (normal (n=9), mild (n=13), moderate (n=17), severe (n=11) CVD) were investigated macroscopically, histologically (H.-E., picrosirius red) and immunohistochemically (collagen I, III, IV, V, VI, elastin, laminin, fibronectin, heparan sulphate). In normal MV, ECM components were expressed in a typical layered pattern. In mild CVD, basement membrane components (laminin, collagen IV, fibronectin) were increased. Advanced CVD was characterized by myxomatous nodular lesions displaying a marginal and a central region comprised mainly of collagen I, VI and fibronectin in the former and collagen I and III in the latter. Collagen IV and laminin appeared multifocally in marked CVD. In conclusion, not only an accumulation of proteoglycans, but also a distinctly altered expression of basement membrane components, and collagens characterizes CVD.

Growth and differentiation of primary and passaged equine bronchial epithelial cells under conventional and air-liquid-interface culture conditions

BackgroundHorses develop recurrent airway obstruction (RAO) that resembles human bronchial asthma. Differentiated primary equine bronchial epithelial cells (EBEC) in culture that closely mimic the airway cells in vivo would be useful to investigate the contribution of bronchial epithelium in inflammation of airway diseases. However, because isolation and characterization of EBEC cultures has been limited, we modified and optimized techniques of generating and culturing EBECs from healthy horses to mimic in vivo conditions.ResultsLarge numbers of EBEC were obtained by trypsin digestion and successfully grown for up to 2 passages with or without serum. However, serum or ultroser G proved to be essential for EBEC differentiation on membrane inserts at ALI. A pseudo-stratified muco-ciliary epithelium with basal cells was observed at differentiation. Further, transepithelial resistance (TEER) was more consistent and higher in P1 cultures compared to P0 cultures while ciliation was delayed in P1 cultures.ConclusionsThis study provides an efficient method for obtaining a high-yield of EBECs and for generating highly differentiated cultures. These EBEC cultures can be used to study the formation of tight junction or to identify epithelial-derived inflammatory factors that contribute to lung diseases such as asthma.

Microscopic examination of endometrial biopsies of retired sports mares: an explanation for the clinically observed subfertility?

After their retirement from sports, performance mares often show a poor breeding success. The objective of this study was the microscopic evaluation of endometrial biopsies of retired sports mares (n = 189) to search for alterations that may explain subfertility. Mares of this study aged 3-23 years showed endometritis (30%) and endometrosis (77%); mild forms predominated. In regard to those mares biopsied during the breeding season (n = 99), 50% had glandular differentiation disorders, i.e. glandular inactivity (8%) or irregular glandular differentiation (42%). Compared to literature data retrieved from mainly non-performance mares, the sports mares of this study showed a similar prevalence of endometrosis and endometritis, but a much higher prevalence of glandular differentiation disorders. The most common cause of the latter is an ovarian dysfunction. Results of this study indicate an association between glandular maldifferentiation of the endometrium and the clinically observed reduced fertility of retired sports mares.

Endocardial Laser Ablation for the Treatment of Atrial Fibrillation in an Acute Sheep Model

Abstract  Background: The purpose of this study was to test the feasibility, effectiveness, and safety of the use of a new laser energy catheter for linear endocardial ablation in an acute sheep model. Methods: Bipolar pacing electrodes were positioned on the left atrial appendage (LAA) and the pulmonary veins (PVs). Laser ablation within the left atrium was performed around the LAA and PVs in six sheep. The temperature in the esophagus was measured continuously during ablation. The animals were weaned from cardiopulmonary bypass (CPB) and were sacrificed two hours after ablation. The heart, lungs, and esophagus were retrieved for histological examination. Results: Aortic cross clamp time was 26.2 ± 6.1 minutes and CPB time was 81 ± 29 minutes. Electrical isolation of the LAA and PVs was confirmed in all sheep. On histological analysis, there was an extensive transmural alteration of the left atrial tissue including vascular lesions, myocardial degeneration, and necrosis, and epi‐ and endocardial necrosis. In six out of six cases, extensive lesions of the esophagus (muscular layer) were also found. Significant changes in esophageal temperature were observed, reaching up to 70 °C. The epithelial layer of the esophagus was not affected by the laser energy, but mild focal degeneration of the subepithelial connective tissue was observed in all sheep. There were no injuries to the circumflex coronary artery. Conclusions: Laser is an effective tool in endocardial ablation, resulting in electrical isolation and transmurality. Future studies should more completely assess the safety of laser ablation, especially with regards to the nearby esophagus, as well as examine the results of epicardial application.

Tumors and Tumor-like Lesions in the Mammary Gland of 24 Pet Rabbits A Histomorphological and Immunohistochemical Characterization

The aim of this retrospective study (2004–2011) was to examine mammary tumors and tumor-like lesions in 24 pet rabbits by histopathology and immunohistochemistry. Rabbits were aged 2 to 8 years. Seventeen were female and 7 female-spayed. Diagnosed tumor-like lesions were lobular hyperplasia (2 rabbits) and multiple cysts (10 rabbits). Tumors included cystadenoma (7 tumors; 3 rabbits), intraductal papilloma (2 tumors; 1 rabbit), intraductal papillary carcinoma (1 tumor), adenocarcinoma (14 tumors; 13 rabbits), adenosquamous carcinoma (2 tumors; 2 rabbits), and matrix-producing carcinoma (1 tumor). The most frequently diagnosed lesion was invasive carcinoma (n = 17). Ten rabbits had several lesions. Immunohistochemistry for calponin and p63 showed that the diagnosed tumor-like lesions, benign tumors, and noninvasive carcinoma had a peripheral myoepithelial layer that was lacking in the invasive carcinomas. In 13 of 14 (93%) of the invasive carcinomas, however, there were variable numbers of calponin- and/or p63-immunopositive cells ranging from 0.1% to 40% with morphological features of either retained nonneoplastic myoepithelial cells or neoplastic epithelial cells with a myoepithelial differentiation. Tumor recurrence was reported in the rabbit with the matrix-producing carcinoma and in 3 rabbits with mammary adenocarcinomas displaying ≥20 mitotic figures in 10 high-power fields and high numbers of neoplastic cells with a myoepithelial differentiation (19%–39%). The rabbit with the matrix-producing mammary carcinoma developed cutaneous metastases confirmed by histopathology. This study shows that different types of mammary tumor-like lesions and tumors can occur in pet rabbits.

Prototheca species and Pithomyces chartarum as Causative Agents of Rhinitis and/or Sinusitis in Horses.

Pyogranulomatous rhinitis associated with an algal infection was diagnosed in a 25-year-old gelding and a 23-year-old mare had necrotizing sinusitis with intralesional algae and pigmented fungi. Algae were identified immunohistochemically in both cases as Prototheca spp. In the gelding, further characterization by polymerase chain reaction and sequencing revealed that the organism was Prototheca zopfii genotype 2. Fungi from the mare were identified as Pithomyces chartarum by molecular analysis. Prototheca species are achlorophyllous algae and P. chartarum represents a dematiaceous fungus; they are saprophytes and facultative pathogens. Prototheca spp. and P. chartarum should be considered as rare respiratory pathogens of horses.

Equine endometrial vascular pattern changes during the estrous cycle examined by Narrow Band Imaging hysteroscopy

The aim of this study was to evaluate the uterine blood supply and endometrial vessel architecture, during the equine estrous cycle. Narrow Band Imaging (NBI) hysteroscopy was used for evaluating changes in the endometrial vasculature during the estrous cycle [six mares, d 0 (representing the day of ovulation), d 6 and 11 in four locations]. In addition, endometrial biopsy samples were used for immunodetection of markers for angiogenesis (Vascular Endothelial Growth Factor A, its receptor 2, as well as angiopoietin-2 and its receptor-tyrosine-kinase Tie2) during the estrous cycle (three mares, d 0, 5 and 10; one biopsy per mare). Detailed analysis of hysteroscopic images revealed an increase in the vascular density from estrus towards diestrus. In contrast, microscopic specimens prepared from biopsies revealed no evidence for changes in the endometrial vessel number during the estrous cycle. Studies on expression of angiogenesis markers indicated that cyclic changes in the endometrial vascular density observed by NBI-hysteroscopy were not due to formation of new vessels. It is concluded that vessels are involved in blood supply of a smaller area during diestrus, facilitating better distribution of nutrients during this phase.