Functional and morphological comparison of extracellular matrices derived from porcine small intestinal submucosa and porcine dermis to support rabbit uterus regeneration.

he aim of this study was to compare the ability of extracellular matrices (ECMs) of various structural origins to support uterus regeneration and maintain contractile function. The experiment was carried out in 18 New Zealand white female rabbits divided into a control group and two experimental groups. In the control group, bipolar electrodes were attached to the uterine horns to collect electromyography data. In the experimental groups, uterine horns were partially excised with immediate implantation of the extracellular matrix (ECM) derived from porcine small intestinal submucosa (SIS), DynaMatrix®, or from porcine dermis, Medeor® Matrix. Twelve weeks later, bipolar electrodes were attached to the regeneration areas in both experimental groups. The electromyography data in all groups were continuously recorded after administration of a single dose of estradiol valerate. Fourteen weeks after EMCs implantation, the rabbits were spayed, and the uterine wall was sampled for histological and immunohistochemical evaluation. The regenerated uterus retained the myoelectric activity pattern, and the mean amplitudes of maximum deflections did not differ between the experimental and control groups. The regeneration supported by the SIS-derived ECM was more advanced than that supported by the dermal-derived ECM. However, some pathological changes were noted in both experimental groups within the regeneration areas.

Effect of parenteral administration of selenium and vitamin E on health status of mammary gland and on selected antioxidant indexes in blood of dairy cows.

This study focuses on the effect of parenteral administration of Selenium (Se) and vitamin E on concentration of Se in plasma and the activity of glutathione peroxidase (GPx) in the blood of dairy cows during peripartal period and their effect on the reduction of clinical mastitis. From a 220 individuals Holstein herd in a two-four lactation-gestation cycle the control group (C), 1st (D1) and 2nd (D2) experimental group were selected. Every group consisted of 15 cows in the last phase of the pregnancy. All cows were fed with the diet containing 0.1 mg of Se per kg/DM. The blood samples from vena jugularis were collected approximately 21 days before calving (control sampling), 3 days, 12 days and 21 days after calving. On the day of control sampling and 12 days before calving in D1 group, cows were injected subcutaneously in the sprescapular region with preparation Selevit inj. a.u.v. at the doses of 48.4 mg/head of Se, and 550 IU/head of alpha-Tocoferol (alpha-Toc). In D2 group, cows were injected by the same preparation only on 21th day before calving with the same doses of Se and alpha-Toc. The increase in the concentration of Se in the plasma and activity GPx in blood in D1 group on the 3rd day and 12th day after calving were determined. Increase in plasmatic concentrations alpha-Toc on 3rd day after calving and reduction of occurrence of clinical mastitis (13.3%) as compared with control group were found.

The effects of aneurysm repair using an aortic prosthesis on the electrical parameters of the muscular layer of the abdominal aorta.

The study was carried out on 10 swine of 20-30 kg body weight. Five animals were assigned to each of 2 groups. An aneurysm of the abdominal aorta was created experimentally in animals from the first and second study group. After 4 weeks, animals from the second group were subject to aneurysm repair using an aortic prosthesis. During the experiment, we measured the myoelectric activity of the muscular layer of the abdominal aorta and aneurysmal lesion with the ultrasonographic technique. Measurements of the aorta and aneurysmal lesion and histopathological analyses were carried out post-mortem. We found a statistically significant decrease in the myoelectric activity of the aorta on the aorta-straight prosthesis interface and a significant decrease in the thickness of the muscular layer of the aorta on the aorta-prosthesis interface. No similar changes were found for experimentally induced aneurysms of the abdominal aorta. A straight prosthesis graft may not be the perfect option in the treatment of abdominal aortic aneurysm, as it contributes to the remodelling of the tissue on the prosthesis-aorta interface. This may result in the relapse of an aneurysm and post-operative complications.

Experimental methods of abdominal aortic aneurysm creation in swine as a large animal model.

Animal models of abdominal aortic aneurysms (AAA) enable preclinical studies on new therapeutic approaches and help to understand pathophysiology of the disease. The aim of this study was to demonstrate the effectiveness of selected methods of experimental induction of abdominal aortic aneurysm in swine and to adapt the EMG examination (electromyography) to record the vessel wall changes. The animals were divided into 3 groups comprising 4 individuals in whom AAA was surgically induced. In the first group the AAA was induced by mechanical stretching of the aortic wall and injection of 500 IU elastase under pressure. The second group received elastase and 6000 IU of collagenase. In the third group 0.5 M CaCl2 solution was introduced additionally. Enlargement of abdominal aorta was monitored for 4 weeks. The first group did not show any aorta dilatation. In the second group the aortic lumen was dilated on average by 71±3.5% (P≤0.001) as shown at autopsy and by 76.6±9.3% as measured by the ultrasound method. In the third group aorta was dilatated by 104.2±11.3% as obtained by ultrasound and 72±3% at post-mortem examination. Myoelectric activity of VSMC (vascular smooth muscle cell) was demonstrated and it was characterized by the presence of three types of waves closely related to the pressure changes in the vessel lumen. We conclude that collagen fibers damage plays a significant role in the AAA development in swine. The inflammatory process in the vessel's wall also contributes to AAA development. However, myoelectrical activity of VSMC does not significantly change despite histologically confirmed loss of muscular layer.

In vitro study on the effects of some selected agonists and antagonists of alpha(1)-adrenergic receptors on the contractility of the aneurysmally-changed aortic smooth muscle in humans.

The study included 18 sections of the aneurysmally-changed abdominal aortas, obtained from patients of the Provincial Specialist Hospital in Wroclaw and 18 sections of normal abdominal aortas obtained from swine. The collected samples were placed horizontally in the incubation chamber. Changes in their transverse section area were registered. They were stretched to a tension of 5 mN. Krebs-Henseleit buffer was used as the incubatory environment. Incubation of the sections was performed at a temperature of 37°C, in the gaseous mixture of oxygen and carbon dioxide used in the following proportion: 95% of O(2) and 5% of CO(2). Contractions of the aorta were registered with isotonic transducers (Letica Scientific Instruments). In the studies, we examined the influence of α(1)-adrenergic receptors (and their subtypes α(1A), α(1B), α(1D)) on the contractility of the aortic muscle in humans and swine by their stimulation or inhibition with some selected agonists or antagonists. This time, it was shown that the stimulation of α(1)-adrenergic receptors leads to contractions of the human and swine aortic muscle; the observed increase in the muscle tone may follow from the stimulation of all subtypes of alpha-1 receptor (α(1A), α(1B), α(1D)). All three subtypes of 1-adrenergic receptor are engaged in vasoconstriction, especially of α(1A) and α(1D) subtypes; the α(1B) subtype is less significant for aortic contractility. The contractile response of the aneurysmally-changed abdominal aorta in humans to agonists of α-adrenergic receptors was significantly less intense than that of the normal porcine aorta. It can be concluded that aneurysms influence the contractile response of the aorta.

Morphological investigations of the occipital area in adult American Staffordshire Terriers.

Morphological investigations into the occipital area were carried out on the skulls of 24 adult American Staffordshire Terriers. The dorsal notch was found in one skull. The normal height (h) and width (W) of the foramen magnum was measured, and the foramen magnum index was calculated. In the case of the presence of the dorsal notch, total height (H) and normal height (h) of foramen magnum were measured, and dorsal notch height (N) was estimated. The mean value of the foramen magnum index (FMIa = W/H × 100) was 82.7. The foramen magnum index with the exception of the skull with dorsal notch (FMIb = W/h × 100) was 77.89. The dysplasia index (ISD = N/h × 100) was 44.05. A radiographic evaluation was made according to the method introduced by Rusbridge. Occipital dysplasia is not a clinical problem itself but can provoke one.