The canine hair cycle - a guide for the assessment of morphological and immunohistochemical criteria

The hair follicle has a lifelong capacity to cycle through recurrent phases of controlled growth (anagen), regression (catagen) and quiescence (telogen), each associated with specific morphological changes. A comprehensive classification scheme is available for mice to distinguish the cycle stages anagen I-VI, catagen I-VIII and telogen. For dogs, such a classification system does not exist, although alopecia associated with hair cycle arrest is common. We applied analogous morphological criteria and various staining techniques to subdivide the canine hair cycle stages to the same extent as has been done in mice. Of all the staining techniques applied, haematoxylin and eosin stain, Sacpic, Masson Fontana and immunohistochemistry for vimentin and laminin proved to be most useful. To evaluate the applicability of our criteria, we investigated skin biopsies from healthy beagle dogs (n=20; biopsies from shoulder and thigh) kept in controlled conditions. From each biopsy, at least 50 hair follicles were assessed. Statistical analysis revealed that 30% of the follicles were in anagen (12% early and 18% late), 8% in catagen (2% early, 5% late and 1% not determinable) and 27% in telogen. Thirty-five per cent of hair follicles could not be assigned to a specific cycle stage because not all follicles within one biopsy were oriented perfectly. In conclusion, this guide will not only be helpful for the investigation of alopecic disorders and possibly their pathogenesis, but may also serve as a basis for research projects in which the comparison of hair cycle stages is essential, e.g. comparative analysis of gene expression patterns.     

Earthquake dating: an application of carbon-14 atom counting

Milligram-sized specimens of detrital charcoal from soil layers associated with prehistoric earthquakes on the Wasatch fault in Utah have been dated by direct atom counting of carbon-14 with a tandem Van de Graaff accelerator. The measured ratios of carbon-14 to carbon-12 correspond to ages of 7800, 8800, and 9000 years with uncertainties of +/- 600 years.     

Promotion of the cycling of diet-enhancing nutrients by african grazers

Experiments in Serengeti National Park, Tanzania, provide direct evidence that large, free-ranging mammalian grazers accelerate nutrient cycling in a natural ecosystem in a way that enhances their own carrying capacity. Both nitrogen and sodium were at considerably higher plant-available levels in soils of highly grazed sites than in soils of nearby areas where animal density is sparse. Fencing that uncoupled grazers and soils indicated that the animals promote nitrogen availability on soils of inherently similar fertility and select sites of higher sodium availability as well as enhancing that availability.     

IMAGING DIAGNOSIS—TEMPOROMANDIBULAR JOINT DYSPLASIA IN A BASSET HOUND

A 5‐month‐old intact male Basset Hound presented for evaluation of pain and crepitation during manipulation of the temporomandibular joint, worse on the right side. A computed tomography (CT) scan of the head was performed. The CT images demonstrated the osseous features of temporomandibular joint dysplasia and facilitated a 3D reconstruction, which allowed better visualization of the dysplastic features. The patient responded to conservative management with a tape muzzle with no recurrence reported by the owner 6 months after presentation.     

Environmental flow releases trigger spawning of a threatened fish: Research insights and publication enhance management,credibility and relationships

1. Publication is an important stage in the research process, but determining the impact of published research on environmental outcomes is a complex challenge that is seldom undertaken. In 2016, a published study used acoustic telemetry techniques and drift sampling to demonstrate that environmental flow releases triggered downstream spawning migrations by a threatened fish species, the Australian grayling (Prototroctes maraena). The study provided support for the use of these types of releases to mitigate some of the effects of river regulation on fishes.
2. The impacts of this research and its publication in Aquatic Conservation: Marine and Freshwater Ecosystems were thoroughly reviewed to identify benefits to water managers, researchers, institutes, and the wider community.
3. Five areas in which this research, and its publication, had a recognizable impact are enhanced confidence for water managers in undertaking actions; greater acceptance in the wider community of environmental flow releases; enhanced relationships among water managers; the credibility arising from the work being published in a peer‐reviewed journal; and setting a foundation for further evidence‐based management.

     

Einfluss der Zwischenlagerung auf die anfängliche Entwicklung rekultivierter Oberböden

Influence of temporary stockpiling on the initial development of restored topsoils Due to increasing construction and open‐cast mining activities on fertile agricultural land, excavation, stockpiling, and restoration of soils have become important issues in soil protection. In this study, we performed a restoration experiment to investigate how the conditions during stockpiling may influence initial soil development and plant growth on a restored site. Four topsoils, which originated from two depths (with uninhibited and inhibited aeration) of a nontrafficked and a trafficked topsoil deposit, were repacked in strips and sown with three meadow‐seed mixtures in strips perpendicular to the soil strips. During stockpiling as well as during the first 2 years after restoration, we assessed the physical and mechanical properties of the topsoils and (after restoration) also plant growth. None of the investigated properties of the topsoils was influenced by the depth in the deposit. In contrast, the coarse porosity and compression index were lower, whereas the bulk density and precompression stress were higher in the trafficked than in the nontrafficked topsoil deposit. However, these differences largely disappeared already in the course of soil restoration. Contrary to our expectations, the plants grew better on the soil of the trafficked topsoil deposit than on the soil of the nontrafficked topsoil deposit in the year of restoration. This might be attributed to the extremely dry and hot summer of that year. In the course of the 2 years following restoration, also the differences in plant growth tended to disappear. The remaining differences in bulk density and plant growth could not be attributed to differences in stockpiling conditions. The results suggest a re‐examination of current soil restoration guidelines. The maximum permitted stockpiling heights for topsoils might be increased in order to reduce the areas required for temporary stockpiling.     

Der Apfelblattsaugerherd in Egnach (Schweiz)

Ohne Zusammenfassung Mit 9 Abbildungen.     

Histological immunoenzyme techniques in canine tissues: evaluation of various methods and modifications

Several antigens including immunoglobulin light and heavy chains, C3, macrophage enzymes and various brain proteins were demonstrated immunohistologically in paraffin sections of canine tissues. The indirect immunoperoxidase, the unlabelled antibody enzyme (PAP), double bridging PAP, and biotinavidin-peroxidase (BAP) methods were compared. The influence of various histological procedures such as fixation and embedding, and other modifications such as enzyme treatment of sections was investigated. The best results were obtained with the PAP and BAP methods on formalin fixed tissues. Trypsin proved to be highly effective for demonstrating certain antigens but required firm adhesion of the sections. Prolonged incubation with the primary antisera improved the results considerably. Based on the results of this study a general strategy for solving immunohistological problems has been proposed.