The spatio-temporal distribution of aromatase cytochrome in ovary throughout the canine oestrous cycle

CONTEXT

New animal welfare legislation and ethical guidelines encourage alternative approaches for canine contraception, instead of surgical gonadectomy which is considered invasive and unjustified in healthy dogs.

AIMS

Reversible contraception might be achieved by inhibition of aromatase (CYP19), an enzyme catalysing the conversion of androgens to oestrogens. This study provides insights into the spatio-temporal expression and distribution of aromatase in canine ovarian tissue.

METHODS

Ovarian tissue was collected from 39 healthy and sexually mature bitches during different stages of the oestrous cycle: pro-oestrus (n =8), oestrus (n =12), dioestrus (n =9) (luteal phase) and anoestrus (n =10). Localisation of cytochrome P450 aromatase was determined by immunohistochemistry.

KEY RESULTS

Aromatase activity in the dog is high during pro-oestrus, ovulation and early dioestrus. Comparing types of follicles and corpora lutea, the highest aromatase abundance was found in antral follicles and luteinising follicles, whereas corpora lutea and early antral follicles showed an intermediate presence of the enzyme. Interesting was the high abundance of aromatase in luteinising theca interna cells, prevailing over granulosa cells.

CONCLUSIONS AND IMPLICATIONS

Understanding of cells involved in oestradiol production is important for targeted inhibition of oestradiol synthesis, possibly offering an approach for contraception and suppression of oestrus.

Ovarian and uterine changes during the oestrous cycle in female dogs

CONTEXT

An accurate staging of sexual cycle is essential for the optimum timing of medical interventions.

AIMS

Here, an updated insight into clinical, endocrinological and vagino-cytological parameters, and their correlation with histomorphology of ovarian and uterine tissue samples is presented.

METHODS

Samples from 39 dogs were collected at various stages of the oestrous cycle: pro-oestrus (n =8), oestrus (n =12), dioestrus (n =9) (luteal phase) and anoestrus (n =10), according to clinical observations. Final allocation of samples was done after histomorphological evaluation of all tissues. Peripheral oestradiol-17ß (E2) and progesterone (P4) concentrations were measured, P4 by both chemiluminescent immunoassay (CLIA) and radioimmunoassay (RIA).

KEY RESULTS

Differences were observed between determination of the stage of the oestrous cycle, either by clinical, endocrinological or histomorphological evaluation. Individuals considered to be in clinical and endocrinological oestrus, had entered the luteal phase according to histomorphology. P4 concentrations measured by two different assays differed, underlying the importance to understand that absolute P4 concentrations may deviate depending on the used assay. Comparison of E2 and P4 concentrations is suggested to be useful when defining the transition from early follicular phase to the time of ovulation.

CONCLUSIONS AND IMPLICATIONS

Based on parallel histomorphological observations, combined with clinical and endocrinological findings on the same individuals, the present study emphasises that an accurate classification of the stage of the cycle in female dogs based solely on clinical and endocrinological assessments can be difficult. The histomorphological findings presented herein provide new insights into the transitional phases between the different stages of the oestrous cycle in the dog.

Administration of aromatase inhibitor MPV-2213ad to blue fox vixens (Vulpes lagopus) as a model for contraception in female dogs

The interest in non-surgical approaches to contraception and fertility control in female dogs has increased in recent years. In this study the effect of an aromatase inhibitor (finrozole) was evaluated in fur production animals, farmed blue fox vixens, as a model for contraception in bitches. A total of 80 vixens were divided into 4 groups, receiving orally placebo (A) or finrozole 0.5 mg/kg (B), 3.5 mg/kg (C) or 24.5 mg/kg (D) for 21 consecutive days beginning in the pre-ovulatory period of heat. Monitoring of the vixens included clinical signs of heat, measurement of vaginal electrical resistance (VER) as well as oestradiol and progesterone concentrations in plasma. The approximate relation of the start of treatment to ovulation varied from 11 days before to one day after ovulation provided that the LH peak occurred 0.5-2 days before the VER peak and ovulation was then estimated to occur 2 days after the LH peak. Seventy vixens were artificially inseminated within 8 h after a 50 Ω decline in vaginal electrical resistance was detected. Ten vixens were not inseminated. Pregnancy was confirmed by transabdominal ultrasound examination and birth of cubs was recorded. The pregnancy rates in the groups were 89.5% (A), 81.3% (B), 55.6% (C) and 52.9% (D). The average number of live born pups in the four groups was 9.4 (A), 7.0 (B), 5.8 (C), and 3.8 (D), respectively. No deleterious effects (for instance malformations) of finrozole on pups could be verified. The administration of finrozole did not have a significant effect on oestradiol parameters and VER values in vixens. Progesterone values were significantly higher in treatment groups compared with the placebo group. The results indicate that pregnancy could be avoided by finrozole provided that doses of ≥3.5 mg/kg were used and the treatment was initiated at least four days before the day of artificial insemination. This corresponds with two to six days before ovulation provided that the LH peak occurred 0.5-2 days before the VER peak and that ovulation then occurred in average 2 days after the LH peak.

BOARD INVITED REVIEW: Immunocontraception as a possible tool to reduce feral pig populations: recent and future perspectives

The feral pig populations of many countries continue to increase. Scientific studies on population size are scarce, while the numbers of reported observations on presence of and damage caused by feral pigs are increasing. Feral pigs can carry and spread several diseases (including zoonotic), but African Swine Fever (ASF) is of most concern. It is a highly transmissible viral disease associated with an extremely high mortality rate. Since 2009 ASF has appeared in several European countries, with cases being identified first among local feral pigs and consequently in domestic pig production units, indicating a clear linkage with the movement of the feral pig population and the spread of the disease across national boundaries. Control of feral pig populations is currently under discussion. Because massive culling raises questions of animal welfare and ethics, fertility control could represent an important and effective means to control feral pig populations. Contraceptive vaccines have been used with some degree of success in many wild species because they are able to provide a long-term effect without any consequent health problems. However, extensive and efficacious use of vaccines to control feral pig populations is not simple. The aim of this article was to review the progress in immunocontraception use in feral pigs, providing an account of the current status and future perspectives.

Strategies for a direct characterization of phosphoproteins on hydroxyapatite surfaces

We show in this work how systems formed by phosphoproteins on calcium phosphate surfaces can be directly characterized, in real time, in liquid medium, without the need for elution or labeling. Specifically, we show how this is possible by applying three different techniques: ellipsometry, quartz crystal microbalance with dissipation, and atomic force microscopy-based friction force spectroscopy. We apply these techniques to study two different model systems, i.e. those formed upon the adsorption of two model phosphoproteins (κ- and β-casein) on hydroxyapatite (HA) surfaces. Information on the kinetics of adsorption, surface excess, viscoelasticity, water content, thickness of the layers, and protein-surface interaction is provided. Results indicate that both phosphoproteins form homogeneous elastic highly hydrated monolayers on the HA surfaces, the strength of β-casein layers being higher by approximately a factor of 4. Based on the experimental results, models for the conformation of κ- and β-casein molecules adsorbed on HA surfaces are proposed.

NanoWear of Salivary Films vs. Substratum Wettability

The pellicle serves as a multifunctional protective layer, providing, e.g., lubrication and remineralization and also acting as a diffusion barrier. In addition, since the formation of the pellicle precedes the adhesion of micro-organisms, it is also important as a conditioning film. We present a novel approach to study the influence of the water wettability of solid surfaces on the strength of adsorbed salivary films. It is based on studying the wear resistance of the films with an atomic force microscope operated in the friction force spectroscopy mode. This methodology provides the strength of the films in terms of the forces needed for breaking and removing them. Our results indicate that these forces are highly dependent on the water wettability of the underlying substrata, decreasing with increasing hydrophobicity. Thus, this study provides valuable information for the design of materials exposed in the oral cavity, i.e., materials that will minimize plaque formation and be easy to clean.

Improving teamwork between students from two professional programmes in dental education

In Sweden, the National Board of Health and Welfare forecasts a decrease in dentists with 26% and an increase in dental hygienists with 47% until the year of 2023. This, together with changes in both epidemiology, especially of dental caries, and political priorities, calls for an effective and well-developed cooperation between dentists and dental hygienists in future dentistry. Hence, the aim of this project was to investigate whether highlighting teamwork during the undergraduate studies of dental students and dental hygiene students could improve the students' holistic view on patients as well as their knowledge of and insight into each other's future professions. Thirty-four dental students and 24 dental hygiene students participated in the study. At the beginning of their final year in undergraduate education, a questionnaire testing the level of knowledge of the dental hygienists' clinical competences was completed by both groups of students. In addition, activities intending to improve teamwork quality included the following: (i) a seminar with a dentist representing the Public Dental Health Services in Sweden, (ii) dental students as supervisors for dental hygiene students, (iii) planning and treatment for shared patients and (iv) students' presentations of the treatments and their outcomes at a final seminar. The project was ended by the students answering the above-mentioned questionnaire for the second time, followed by an evaluation of the different activities included in the study. The knowledge of dental hygienists' competences showed higher scores in almost all questions. Both groups of students considered the following aspects important: seminars with external participants, dental students acting as supervisors and planning and treating shared patients. By initiating and encouraging teamwork between dental students and dental hygiene students, it is possible to increase knowledge on dental hygienists' competence and also to develop and strengthen a holistic view on patients and dental work, thereby preparing both groups of students for their professional life.

The composition of enamel salivary films is different from the ones formed on dental materials

This study utilized two-dimensional gel electrophoresis (2DE) to illustrate the compositional differences between in vitro salivary conditioning films (denoted pellicles) formed on human enamel as well as on the dental materials titanium and poly(methyl methacrylate). The salivary pellicles were formed by immersing each surface in individual tubes containing small volumes of freshly collected whole saliva. Saliva remaining in the tubes after the pellicle formation for 2 h was visualized by means of 2DE and silver staining. The results showed that the protein patterns in 2DE of the liquid phase of saliva left after the exposure to the respective surfaces, regarding proteins <100 kDa in size, were different depending on the surface used. Several protein groups and/or individual proteins were shown to be distinct for each surface used.

Film-forming properties and viscosities of saliva substitutes and human whole saliva

Hypo-salivation, related to medical remedies, is an increasing clinical problem. Studies report a weak correlation between subjective mouth dryness and objective sialometry. This indicates that both quantity and quality of saliva are important for the surface-associated functions of saliva, such as lubrication and hydration, to be expressed. Film-forming properties and viscosities of three saliva substitutes were compared to human saliva. Adsorption to surfaces was measured by ellipsometry, infrared spectroscopy and drop-volume technique. Viscosity measurements were carried out using an oscillating rheometer. Saliva, with the lowest viscosity value and the highest protein content, presented superior film retention on both hydrophilic and hydrophobic surfaces. The carboxymethylcellulose-based MAS 84 showed intermediate values of viscosity, poorest ability to reduce surface tension, and negligible film-forming capacity. The porcine mucin-based Saliva Orthana showed about twice the viscosity of saliva and film-forming capability on preferably hydrophobic substrates. Salinum, a linseed extract, possessed the highest viscosity value and an initial surface tension close to that of saliva. The film retention on hydrophilic surfaces was not as effective as for saliva. The results indicate that the film-forming capacity of saliva substitutes is a property also to be considered in the exploration of clinically effective artificial salivas.

Bacteria on stumps of amputees and the effect of antiseptics

Amputees get stump infections usually from the natural inhabitants of the healthy skin and probably due to the unnatural environment of tight fitting sockets. The aim of the present study was to investigate the natural stump bacteria and the effect of antiseptics as well as the amputees' evaluation of such treatment. Fifteen amputees using their prostheses all day were investigated. Bacterial samplings were taken by swab technique with respect to bacteria and fungi from the stumps in the morning before prosthetic application and in the evening after a whole day's prosthetic use without antiseptic cleaning; after antiseptic cleaning with a combination of Isopropanol 45%. N-propanol 30% and N-cetyl-pyridiniumchloride 0.2% for one day: after fourteen days continuous use. The patients were asked if they liked the antiseptic and if they would like to continue to use it. Two patients did not submit bacteriological samples after the cleaning period. Before cleaning S. epidermidis, S. aureus and alpha-hemolytic streptococci were commonly found. In two instances gram negative rods were found. After the cleaning period there was a reduction of bacteria in 11 out of 13 patients. All patients liked the antiseptic and the simplicity by which the stumps and the sockets could be kept clean. The authors feel that the use of antiseptics to increase stump and socket hygiene is justified.

Comparison of CAD-CAM and hand made sockets for PTB prostheses

The aim of the present study was to compare sockets for below-knee (BK) prostheses made by Computer Aided Design-Computer Aided Manufacture (CAD-CAM) to those made by hand. The patients in the study were provided with two prostheses each, which apart from the sockets, were identical. One socket was made by the CAD-CAM technique developed at the Bioengineering Centre, Roehampton, University College London and one was made by hand at the OT-Centre, Stockholm, Sweden. The results were based on investigation of eight unilateral below-knee amputees evaluating their own sockets by Visual Analogous Scale with respect to comfort, pressure, and pain. The sockets were evaluated on seven occasions, at two tests, on delivery, after use every second day for six days and every second week for two weeks. All CAD-CAM sockets except one had to be changed once as compared to the hand made of which only two had to be changed. As to comfort it could not be demonstrated that there was any significant difference between the two types of sockets and both types were well accepted by all patients. Differences in pressure and pain were rarely reported. There were obvious differences between the two types of socket with respect to height, width, and inner surface configuration. The authors feel that CAD-CAM will in the near future be an excellent tool for design and manufacture of prosthetic sockets.