Different fixative solutions in the detection of mast cells in the canine and feline reproductive organs.

BACKGROUND: The aim of the study was to evaluate the usability of different fixative fluids in the detection of mast cells in ovaries and uteri of female dogs and cats. MATERIALS AND METHODS: Samples were fixed in 4% formaldehyde, Carnoy's fluid, Mota's basic lead acetate and isotonic formaldehyde-acetic acid (IFAA). RESULTS: Mast cells (MCs) were detected by acidified toluidine blue staining and counted for various parts of the ovaries and uteri. In the ovaries of both species, the numbers of MCs were significantly (p < 0.05) higher in Carnoy than in formalin. No significant differences were found between Carnoy and Mota (tested only in cats). In the uterus, numbers of MCs were significantly (p < 0.05) higher in Carnoy, Mota and IFAA compared to formalin (canine endometrium, feline endometrium and feline myometrium), in Carnoy and Mota compared to formalin (canine myometrium) and in Mota compared to IFAA (feline myometrium). The majority of MCs were formalin-sensitive in the canine and feline uterus, in the canine ovary and in the feline cortex ovarii. In the feline medulla ovarii, the majority of MCs were formalin-resistant. No formalin-resistant MCs were detected in the feline tunica albuginea ovarii. CONCLUSIONS: Thus, using Mota's or Carnoy's fluid in the canine or feline female reproductive organs is recommended. This study improves methodology for all studies which clarify the role of MCs in the reproductive organs of the domestic and laboratory animals.

Light and scanning electron microscopy of the tongue of the sand lizard (Lacerta agilis).

BACKGROUND: Despite the fact that numerous reptile species are widely studied by the researchers, information describing the detailed structure of particular organs in many reptiles is missing. MATERIALS AND METHODS: The tongue of the sand lizard (Lacerta agilis) was examined under the light and scanning electron microscope. It is divided into bifurcated apex, corpus and bifurcated radix. The tip of the lingual apex is devoid of lingual papillae. RESULTS: The remaining dorsal surface of the tongue bears either fused papillae in the form of caudally directed ridges or individual papillae represented by mu- shroom-like or semilunar prominences (lingual apex) or fish scale-like papillae (lingual corpus) and horizontally laid ridges extending in the form of lobulated prominences (lingual corpus, lingual radix). Regardless of the shape, lingual papillae contain numerous muscle fibres and they are all considered to be mechanical. The lingual epithelium changes from the simple squamous into stratified squamous in the caudal direction. No salivary glands or sensory structures were recognised. CONCLUSIONS: This description is to be used mainly for comparative studies. It could also help to understand how different lizards capture the pray.

Distribution of mast cells in the feline ovary in various phases of the oestrous cycle.

This study is the first description of the distribution of mast cells in various phases of the oestrous cycle in the ovary of cat. Furthermore, this is the first description in species with an induced ovulation. The aim was to describe the distribution of mast cells and variability of their numbers in the feline ovaries in different phases of the oestrous cycle. The number of mast cells in medulla ovarii was affected by the estradiol and progesterone level in the blood serum because the lowest number was detected in anoestrus when the levels of hormones were basal. Nevertheless, both high and low numbers of mast cells were found in oestrus and dioestrus. To conclude, mast cells seem to be essential for the induction of spontaneous ovulation, but they do not play the same role for ovulation itself in cats with induced ovulation.

Azoospermia with variable testicular histology after 7 months of treatment with a deslorelin implant in toms.

The main aim of the study was to assess whether the longer use of a GnRH-agonist implant (deslorelin 4.7 mg, Suprelorin) in toms would lead to the suppression of spermatogenesis comparable with histologic appearance in juvenile animals as was previously described in dogs. The other aims were to monitor the progression of the testes size decrease and development of azoospermia 5 to 7 months after treatment with a GnRH-agonist implant. In animals, 5, 6, and 7 months after GnRH-agonist implant insertion, variable histological appearance of germinal epithelium was found, when tubules with elongating spermatids, round spermatids, spermatocytes, and spermatogonia as the most developed germinal cells were found in each group of toms. In all male cats, 5, 6, and 7 months after implant insertion, testosterone concentrations and testes size significantly differed between the first and the last visit. All animals, except one tom castrated 5 months after implant insertion, developed complete azoospermia. However, in this tom, all spermatozoa were immotile. Treatment with the subcutaneous GnRH-agonist implant was well tolerated, and no treatment-related adverse effects were noted. These results reported the efficacy of 4.7-mg deslorelin implant (Suprelorin) during its 7 months of use. The complete azoospermia confirms its contraceptive effect. However, the histologic evaluation revealed a great individual variability in the degree of spermatogenic suppression. The question as to whether spermatogenesis in toms can be suppressed in all males to the level of spermatogonia/primary spermatocytes after prolonged exposure to deslorelin has yet to be answered.

Reversible suppression of sexual activity in tomcats with deslorelin implant.

The aim of the study was to assess the efficacy of using a Gn-RH agonist implant (deslorelin, 4.7 mg, Suprelorin) to control sexual activity of male cats and reestablishment of sexual function after the implant removal 4 mo after placement. Using a control group (Group 1, n = 5), 22 domestic tomcats were given the implant subcutaneously in the region of the right shoulder blade and were then divided into two treatment groups. Animals in Group 2 (n = 14) were observed from the date of implant surgery and the observation lasted for 4 mo. In Group 3 (n = 8) all animals were monitored from the date of implant surgery. Then, after 4 mo, all implants were removed and the toms were observed for a further 4 mo. In all animals during their first visit and then in 1-mo intervals, changes in testosterone concentrations were assessed before (T0) and 4 h after (T4) human chorionic gonadotropin (HCG) administration and testis size was measured. In all tomcats, semen collection was performed, using an electroejaculator, in the course of the first visit and then in 2-mo intervals or at the end of observation. Total sperm count was determined in each semen sample. Two to four animals were castrated at weeks 4, 8, 12, 16, 20, 24, 28 and 32 and histologic assessment of the testes was performed. By evaluation of 200 cross sections of seminiferous tubules, the degree of spermatogenic suppression was assessed and animals in Groups 2 and 3 were assigned into groups according to most tubules with the most developed germ cell observed: G1, spermatocytes; G2, round spermatids; G3, elongating spermatids and G4, elongated spermatids. The mean area of Leydig-cell nuclei was calculated. In animals in Group 2, suppression after implant insertion was monitored. T4 concentrations, testis size, and total sperm count gradually decreased (P < 0.01; P < 0.01; and P < 0.05, respectively) within 4 mo after implantation. Histologic evaluation showed a high individual variation in the degree of suppression of spermatogenesis. In animals in Group 3, the implant was removed 4 mo after insertion and the return of sexual activity was monitored. Within 4 mo, T4 concentration and total sperm count increased to the physiological values of intact toms. Testes gradually increased in size and within 4 mo of implant removal almost reached pretreatment size. According to histologic evaluation of the seminiferous tubules, as early as 1 mo after implant removal, all animals were assigned to G4, with most tubules containing elongated spermatids as the most developed germ cells. Treatment with the long-term subcutaneous Gn-RH agonist implant was well tolerated and no adverse treatment-related effects were noted. These results demonstrated efficacy of 4.7 mg deslorelin implant (Suprelorin) with high variability of the effect onset in tomcats. Furthermore, the study revealed a strong need for complex examination, including testis size measurement, monitoring of hormonal changes, spermatological analysis and histologic evaluation, to declare the animal infertile. After the implant removal, all observed parameters confirmed the reversibility of the method and gradual return of sexual activity in toms.

EBSD investigation of the microstructure and texture characteristics of hot deformed duplex stainless steel.

The microstructure and crystallographic texture characteristics were studied in a 22Cr-6Ni-3Mo duplex stainless steel subjected to plastic deformation in torsion at a temperature of 1000 degrees C using a strain rate of 1 s(-1). High-resolution EBSD was successfully used for precise phase and substructural characterization of this steel. The austenite/ferrite ratio and phase morphology as well as the crystallographic texture, subgrain size, misorientation angles and misorientation gradients corresponding to each phase were determined over large sample areas. The deformation mechanisms in each phase and the interrelationship between the two are discussed.

EBSD study of the orientation dependence of substructure characteristics in a model Fe-30wt%Ni alloy subjected to hot deformation.

The aim of the present investigation was to determine the orientation dependence of substructure characteristics in an austenitic Fe-30wt%Ni model alloy subjected to hot plane strain compression. Deformation was carried out at a temperature of 950 degrees C using a strain rate of 10 s(-1) to equivalent strain levels of approximately 0.2, 0.4, 0.6 and 0.8. The specimens obtained were analysed using a fully automatic electron backscatter diffraction technique. The crystallographic texture was characterized for all the strain levels studied and the subgrain structure was quantified in detail at a strain of 0.4. The substructure characteristics displayed pronounced orientation dependence. The major texture components, namely the copper, S, brass, Goss and rotated Goss, generally contained one or two prominent families of parallel larger-angle extended subboundaries, the traces of which on the longitudinal viewing plane appeared systematically aligned along the {111} slip plane traces, bounding long microbands subdivided into slightly elongated subgrains by short lower-angle transverse subboundaries. Relatively rare cube-orientated grains displayed pronounced subdivision into coarse deformation bands containing large, low-misorientated subgrains. The misorientation vectors across subboundaries largely showed a tendency to cluster around the sample transverse direction. Apart from the rotated Goss texture component, the stored energy levels for the remaining components were principally consistent with the corresponding Taylor factor values.

EBSD and TEM investigation of the hot deformation substructure characteristics of a type 316L austenitic stainless steel.

The evolution of crystallographic texture and deformation substructure was studied in a type 316L austenitic stainless steel, deformed in rolling at 900 degrees C to true strain levels of about 0.3 and 0.7. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used in the investigation and a comparison of the substructural characteristics obtained by these techniques was made. At the lower strain level, the deformation substructure observed by EBSD appeared to be rather poorly developed. There was considerable evidence of a rotation of the pre-existing twin boundaries from their original orientation relationship, as well as the formation of highly distorted grain boundary regions. In TEM, at this strain level, the substructure was more clearly revealed, although it appeared rather inhomogeneously developed from grain to grain. The subgrains were frequently elongated and their boundaries often approximated to traces of [111] slip planes. The corresponding misorientations were small and largely displayed a non-cumulative character. At the larger strain, the substructure within most grains became well developed and the corresponding misorientations increased. This resulted in better detection of sub-boundaries by EBSD, although the percentage of indexing slightly decreased. TEM revealed splitting of some sub-boundaries to form fine microbands, as well as the localized formation of microshear bands. The substructural characteristics observed by EBSD, in particular at the larger strain, generally appeared to compare well with those obtained using TEM. With increased strain level, the mean subgrain size became finer, the corresponding mean misorientation angle increased and both these characteristics became less dependent on a particular grain orientation. The statistically representative data obtained will assist in the development of physically based models of microstructural evolution during thermomechanical processing of austenitic stainless steels.