C. Veröffentlichungen aus dem Institut 1988

Das Institut Im Jahre 1988

C. Veröffentlichungen aus dem Institut 1988     

Endothelial cells and angiogenesis in the horse in health and disease—A review

The cardiovascular system is the first functional organ in the embryo, and its blood vessels form a widespread conductive network within the organism. Blood vessels develop de novo, by the differentiation of endothelial progenitor cells (vasculogenesis) or by angiogenesis, which is the formation of new blood vessels from existing ones. This review presents an overview of the current knowledge on physiological and pathological angiogenesis in the horse including studies on equine endothelial cells. Principal study fields in equine angiogenesis research were identified: equine endothelial progenitor cells; equine endothelial cells and angiogenesis (heterogeneity, markers and assessment); endothelial regulatory molecules in equine angiogenesis; angiogenesis research in equine reproduction (ovary, uterus, placenta and conceptus, testis); angiogenesis research in pathological conditions (tumours, ocular pathologies, equine wound healing, musculoskeletal system and laminitis). The review also includes a table that summarizes in vitro studies on equine endothelial cells, either describing the isolation procedure or using previously isolated endothelial cells. A particular challenge of the review was that results published are fragmentary and sometimes even contradictory, raising more questions than they answer. In conclusion, angiogenesis is a major factor in several diseases frequently occurring in horses, but relatively few studies focus on angiogenesis in the horse. The challenge for the future is therefore to continue exploring new therapeutic angiogenesis strategies for horses to fill in the missing pieces of the puzzle.     

Progesterone and the surge release of gonadotropins in the ewe

On day 12 of an estrous cycle, 4 groups of ewes were treated with either blank (no steroid) or 3 different sizes of progesterone-containing rubber implants to study the effect of maintained progesterone levels on preovulatory events. Following luteolysis progesterone levels were 0.55 ± 0.13 ng/ml in control ewes and 0.62 ± 0.10 ng/ml, 0.99 ± 0.09 ng/ml and 1.85 ± 0.04 ng/ml in the 3 groups of progesterone-treated ewes. Preovulatory surges of LH and FSH occurred in $\text{5}\text{5}\text{,}\text{5}\text{5}\text{;}\text{4}\text{5}\text{,}\text{3}\text{5}\text{;}\text{4}\text{5}\text{,}\text{3}\text{5}$ and $\text{0}\text{5}\text{,}\text{0}\text{5}$ ewes in these 4 groups respectively. Eleven days after implant insertion, all ewes responded to a GnRH challenge. The height of all FSH peaks was depressed by progesterone treatment (P<0.05). Three groups of ewes were ovariectomized at day 6 of a cycle and treated with estradiol-17β and progesterone-containing implants. After 8 days of treatment, progesterone implants were removed in sections to give 3 different rates of decline in serum progesterone levels. The gonadotropin surges occurring following progesterone removal were delayed by the slower rates of progesterone decline. Another group of ewes was treated as in experiment 2, but the progesterone implants were all removed together after 8 days. Subsequent replacement of progesterone implants, after 12 or 18 hours, blocked the gonadotropin surges in all, or 2 of 6 ewes respectively. When replaced after 24 hours, implants producing low progesterone (1.38 ± 0.22 ng/ml) did not block gonadotropin surges, but in 2 of 5 ewes high progesterone did (2.87 ± 0.22 ng/ml). Removal of progesterone implants, 12 or 24 hr after replacement, produced secondary gonadotropin surges of smaller magnitude than the initial peaks (P<0.01).     

PREVALENCE AND CHARACTERIZATION OF SMALL TYMPANIC BONE SPICULES AND DRUMSTICK‐LIKE HYPEROSTOTIC TYMPANIC BONE SPICULES IN THE MIDDLE EAR CAVITY OF DOGS

Rounded, sessile, hyperattenuating structures detected in computed tomography (CT) studies of canine tympanic bullae have been termed “otoliths.” These have been proposed to represent dystrophic mineralizations or heterotopic bone formations in the middle ear that are potentially related to chronic otitis media. Aims of the current study were to describe the prevalence, macroscopic, and histological features of structures consistent with “otoliths” in the canine tympanic cavity. Tympanic bullae from 50 routinely necropsied dogs and 139 retrospectively retrieved CT scans of canine clinical cases were examined. Small tympanic bone spicules with pointed or clubbed tips essentially arising from the free margin of the septum bullae were bilaterally present in the tympanic cavities of all 50 of the necropsied dogs. In 48% of the dogs, “otolith”‐like CT‐detectable bone spicules carrying drumstick‐like hyperostoses that were 1–6 mm in diameter were also present. In the retrospective survey of bulla CT scans of 139 cases, the prevalence of hyperostotic tympanic bone spicules (HTBS) was 20%. Findings from the current study indicated that the presence of small tympanic bone spicules in adult dogs is most likely due to physiological bone growth in the septum bullae and that HTBS represent osseous proliferations of small tympanic bone spicules. However, the factors inducing formation of hyperostotic spicules from small tympanic bone spicules remain unknown. The high prevalence of HTBS displaying a similar appearance in bulla CT scans in dogs suggests that these spicules should be included in a differential diagnosis list for “otoliths.”     

Proteolytic system of Bacillus sp. CL18 is capable of extensive feather degradation and hydrolysis of diverse protein substrates

1. Feathers are recalcitrant protein-rich wastes produced in huge amounts by poultry processing for meat production. Hence, feather bioconversion and protease production by Bacillus sp. CL18 were investigated.

2. Bacillus sp. CL18 demonstrated a remarkable feather-degrading potential. Through cultivations on feather broth (10 g l^?1 feathers), 94.5% ± 3% of whole feathers were degraded after 4 d. Increases in soluble protein contents were observed and protease production was maximal also at d 4. This strain produced diverse proteolytic enzymes during growth.

3. Crude protease displayed optimal activity at 55°C (50–62°C), pH 8.0 (7.0–9.0) and a low thermal stability. Proteolytic activity increased in the presence of Ca²⁺, Mg²⁺, Triton X-100, Tween 20 and dimethyl sulphoxide. Inhibition profile indicated that crude protease contains, mainly, serine proteases. Enzyme preparation hydrolysed mainly casein and soy protein isolate.

4. The keratinolytic capacity of Bacillus sp. CL18 at moderate temperatures (30°C) might be appropriate for feather conversion, resulting in protein hydrolysates and proteolytic enzymes. Proteases are postulated to be added-value products that can be obtained from such a bioprocess.     

Influence of altitudinal variation on the content of phenolic compounds in wild populations of Calluna vulgaris, Sambucus nigra, and Vaccinium myrtillus

This study deals with the effect of altitudinal variation on the content of phenolic compounds in three traditional herbal plants, which are also consumed as food in Central Europe. Herbs of Calluna vulgaris (L.) HULL, flowers and fruits of Sambucus nigra L., and berries of Vaccinium myrtillus L. collected in the Naturpark Solktaler (Austria) were extracted using accelerated solvent extraction (ASE). Identification and quantification of the constituents in the polar extracts (methanol 80%, v/v) were achieved by means of RP-HPLC-PDA and/or LC-PDA-MS analysis with external standards. 3,5- O-Dicaffeoylquinic acid was identified in flowers of S. nigra for the first time. Rising concentrations of flavonoids and especially flavonol-3- O-glycosides with adjacent hydroxyl groups in ring B in C. vulgaris and S. nigra with increasing altitude were observed. Anthocyanins from the berries of both S. nigra and V. myrtillus occurred in decreasing amounts with rising altitude. C. vulgaris showed the best radical scavenging capacity based on the DPPH assay.     

A description of the standardized measurement procedures and recommended threshold limit values for biological hazards in Germany

On the basis of EU directives 89/391/EEC (to encourage improvements in the safety and health of workers at work) and 2000/54/EC (on the protection of workers from risks related to exposure to biological agents at work), biological hazards at work have to be assessed and preventive measures have to be introduced in all member states of the EU. In Germany, national legislation (Biological Agents Ordinance - BioStoffV and Technical Rules on Biological Agents, TRBA) and recommendations of workers' compensation boards define standardized methods for the assessment of airborne mold, bacteria, and endotoxins. This article describes policies and practices in Germany for measurement of airborne bioaerosols and for interpretation of measurements relative to the standards. As an example, methods and results of measurements in agriculture are shown. The standardized measurement procedures proved suitable for use in livestock buildings. The results of the exploratory measurements in different livestock buildings confirmed the often high concentrations of airborne biological hazards in agriculture that are reported in the literature.