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Pre-exposure prophylaxis (PrEP) is a pivotal intervention among HIV prevention strategies. We aimed to narratively revise the topic of HIV acute infection in the setting of PrEP exposure with a focus on diagnostic options, clinical features, and future PrEP perspectives, with a particular focus on users with high adherence to PrEP. We searched the main databases (PubMed, Embase, and Scopus) with the keywords "PrEP" or "Pre-Exposure Prophylaxis" and "HIV" or "PLWH" and "breakthrough" or "acute infection" or "primary infection". We included all randomized clinical trials and non-experimental studies (both case reports and observational studies) ever published. In the present narrative review, we revise the diagnostic challenges related to HIV diagnosis in the setting of PrEP and the clinical characteristics and symptoms of breakthrough infections. We discuss the management of acute HIV infection during PrEP and the new challenges that arise from the use of long-acting drugs for PrEP. Our review underlines that although extremely rare, HIV seroconversions are still possible during PrEP, even in a context of high adherence. Efforts to promptly identify these events must be included in the PrEP follow-up in order to minimize the chance of overlooked HIV breakthrough infections and thus exposure to suboptimal concentrations of antiretrovirals. [ABSTRACT FROM AUTHOR]

Simple Summary: Reliable assessment of ovarian tissue depends on the ability of the fixation protocol to preserve its near in vivo appearance and composition. The goal of this study was to find the most suitable fixation protocol for feline ovarian tissue. Equal ovarian tissue fragments were obtained and divided into three groups then fixed with three different fixatives (Bouin, neutral buffered formalin [NBF] and form acetic acid) for five time points and assessed for histology and immunohistochemistry. Bouin exhibited good results for morphology but not immunohistochemistry, while NBF exhibited the best results for immunohistochemistry but not morphology. The most suitable fixative for both morphology and immunohistochemistry was form acetic acid, which invariably makes it a better alternative for feline ovarian tissue studies. Fixatives and fixation protocol have a profound effect on both the morphology and epitope sensitivity of ovarian tissue, which hampers accurate ovarian tissue evaluation. We aimed to establish the most suitable fixation protocol for feline (Felis catus) ovarian tissue. Fragments (1.5 mm diameter) were punched from 1 mm-thick feline ovarian tissue, divided into three groups then fixed with three different fixatives (Bouin, neutral buffered formalin [NBF] and form acetic acid [new compound fixative formulation for ovarian tissue composed of 5% acetic acid in NBF]) for five fixation periods. Subsequently, fragments were processed and evaluated for the morphology and intensity of immunohistochemical signals against three antigens (Ki-67, MCM-7 and activated caspase-3). Proportions of grade 1 or morphologically intact follicles were significantly lower in NBF when compared with Bouin and form acetic acid fixatives. However, Bouin fixative had the lowest mean DAB intensity (p < 0.05) in all three antigen targets, while NBF had the highest (p < 0.05) in Ki-67 and caspase-3, but in MCM-7, it was no different from form acetic acid. In conclusion, form acetic acid maintained ovarian tissue architecture with excellent follicular morphology in the same manner as Bouin fixative, and it also maintained reasonable DAB signals similar to NBF, thus providing a better alternative for feline ovarian tissue studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Hunting pressure and loss of habitat exacerbated by climate change have led to a decline in the number of many galliform species, especially those found in the wild. One such species is the Congo peacock, which has been classified as vulnerable. A domestic galliform species such as the domestic turkey can conceivably be used as a model to research and understand reproduction patterns of related wild and endangered species. The collection, preservation and use of the male gametes for assisted reproductive techniques are key to the successful breeding of such species. This study was aimed at developing a suitable semen extender using two extender formulations (egg yolk-based and soybean-based with or without L-ascorbic acid supplementation) and two storage protocols (ambient temperature and chilled). The results show that both extender formulations preserved turkey semen viability for up to 6 h at ambient temperature and up to 24 h at the chilling temperature. In conclusion, the two extenders were similar with regard to semen quality parameters, and L-ascorbic acid supplementation of the turkey semen extenders improved semen quality during liquid storage. Populations of many galliform species have declined mainly due to habitat loss and over-hunting, notably the Congo peacock, which has been classified as a vulnerable species by the International Union for Conservation of Nature (IUCN). The domestic turkey, being a species of least concern, which has been reported to be closely related to peacocks, could serve as a model for the optimization of assisted reproductive technologies for the Congo peacock. This study was aimed at developing a suitable turkey semen extender for artificial insemination in field conditions. Semen was collected using the dorso-abdominal massage technique from seven turkey toms and analyzed. Ejaculates with >70% motility and >80% live spermatozoa were pooled and divided into four aliquots (four treatments). Each of the four treatments was extended in a soybean-based extender or an egg yolk-based extender, with or without L-ascorbic acid. Two liquid preservation protocols (ambient temperature (35 °C) and chilled (4 °C)) were employed, and quality parameters including motility, viability and morphology were evaluated. The results show that the two extenders were similar with regard to semen quality parameters, and L-ascorbic acid supplementation of the turkey semen extenders improved semen quality during liquid storage. [ABSTRACT FROM AUTHOR]

Simple Summary: Semen freezing in dogs is a field of growing interest. The international shipment of cryoconserved semen contributes to the avoidance of long travels and long-term storage of valuable gametes. However, the collection of one semen portion on average results in one to three doses for artificial insemination, which is a poor result in comparison to the outcome in large animals. The costs for the owners are therefore rather high. In individual dogs, the semen quality of raw semen is good; however, it could be suboptimal after thawing. To avoid costly freezing of these low-quality ejaculates, markers of freezability are useful. An abundance of markers are available for large animals, but not for dogs. This review provides an overview on markers for freezability of canine semen. Markers of freezability allow the selection of ejaculates of good freezability. So far, most investigations were conducted in boars, bulls, rams and horses, with high economic interests triggering the efforts. The progress in dogs is comparably slow. A critical evaluation of the methods requires consideration of practicability, with most labs not even possessing a computer assisted sperm analyser (CASA); furthermore, small canine ejaculates mostly do not allow the use of large semen volumes. In dogs, modern markers of freezability no longer assess single membrane constituents or seminal plasma components but comprise tests of cell functionality and adaptability, energy metabolism, cluster analyses of kinetic and morphometric parameters, as well as DNA intactness. Identification of the most efficient combination of tests seems useful. At present, examination by CASA combined with cluster analysis of kinetic subgroups, JC-1 staining and COMET assay or staining with toluidine blue seem most appropriate; however, cell volumetry and other functional tests deserve better attention. A better understanding of spermatozoa energy metabolism might reveal new markers. This review focuses on the requirements and markers of freezability of canine semen, highlighting potential future candidates. [ABSTRACT FROM AUTHOR]

Simple Summary: In assisted reproduction, in vitro embryo production is the generation of embryos from isolated gametes in an equipped laboratory. This procedure is commonly employed in humans as well as in animals to preserve or improve their fertility, but while it works well in some species, such as cattle, it still faces some challenges in others, such as cats and dogs, which are important animal models to develop assisted reproduction techniques for related wild, endangered species. Traditionally, gametes and embryos are cultured in vitro on glass or plastic dishes, but these supports are very different from the ovarian follicles, the oviducts, or the uterus, which are the physiological environments where oocytes and embryos grow and develop. This review article describes these culture systems, the cellular alterations that could arise from their use, and it illustrates innovative possibilities (e.g., three-dimensional or microfluidic cultures) that could improve the outcomes of in vitro cultured feline and canine reproductive cells. In vitro embryo production in cats and dogs still presents some challenges, and it needs to be optimized to transfer efficient protocols to related wild, endangered species. While the chemical composition of culture media has been the focus of several studies, the importance of culture substrates for oocyte and embryo culture has often been neglected. Traditional in vitro systems, i.e., two-dimensional cultures, do not resemble the physiological environments where cells develop, and they may cause morphological and functional alterations to oocytes and embryos. More modern three-dimensional and microfluidic culture system better mimic the structure and the stimuli found in in vivo conditions, and they could better support the development of oocytes and embryos in vitro, as well as the maintenance of more physiological behaviors. This review describes the different culture systems tested for domestic carnivore reproductive cells along the years, and it summarizes their effects on cultured cells with the purpose of analyzing innovative options to improve in vitro embryo production outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Oocyte vitrification is a cryopreservation method that guarantees the long-term conservation of genetic material and fertility potential in humans and wild or domestic animals. However, in the domestic cat the in vitro embryo development of immature vitrified oocytes is not yet satisfactory. In this study, a three-dimensional (3D) culture system was used for the in vitro embryo production of vitrified oocytes to provide conditions more similar to those of the in vivo microenvironment, and for comparison, control vitrified oocytes were cultured in two-dimensional (2D) conditions. Embryos were cultured for seven days and their development was assessed. The results showed that the 3D enriched culture system was able to sustain the in vitro maturation and the subsequent embryo development of vitrified oocytes, but no differences were found with the 2D system and improvements to enhance the development of vitrified oocytes are still needed. Cryoinjuries severely affect the competence of vitrified oocytes (VOs) to develop into embryos after warming. The use of culture conditions that provide physical and chemical support and resemble the in vivo microenvironment in which oocytes develop, such as 3D scaffolds and coculture systems, might be useful to improve VOs outcomes. In this study, an enriched culture system of 3D barium alginate microcapsules was employed for the in vitro embryo production of domestic cat VOs. Cryotop vitrified-warmed oocytes were in vitro matured for 24 h in the 3D system with or without fresh cumulus-oocyte complexes (COCs) in coculture, whereas a control group of VOs was cultured in traditional 2D microdrops of medium. After in vitro fertilization, presumptive embryos were cultured in 3D or 2D systems according to the maturation conditions. Vitrified oocytes were able to mature and develop into embryos in 3D microcapsules (17.42 ± 11.83%) as well as in 2D microdrops (14.96 ± 8.80%), but the coculture with companion COCs in 3D resulted in similar proportions of VOs embryo development (18.39 ± 16.67%; p = 1.00), although COCs presence allowed for blastocyst formation (0.95 ± 2.52%). In conclusion, embryos until late developmental stages were obtained from cat VOs, and 3D microcapsules were comparable to 2D microdrops, but improvements in post-warming conditions are still needed. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is constantly evolving, leading to new variants. We analysed data from 4400 SARS-CoV-2-positive samples in order to pursue epidemiological variant surveillance and to evaluate their impact on public health in Italy in the period of April-December 2021. The main circulating strain (76.2%) was the Delta variant, followed by the Alpha (13.3%), the Omicron (5.3%), and the Gamma variants (2.9%). The B.1.1 lineages, Eta, Beta, Iota, Mu, and Kappa variants, represented around 1% of cases. There were 48.2% of subjects who had not been vaccinated, and they had a lower median age compared to the vaccinated subjects (47 vs. 61 years). An increasing number of infections in the vaccinated subjects were observed over time, with the highest proportion in November (85.2%). The variants correlated with clinical status; the largest proportion of symptomatic patients (59.6%) was observed with the Delta variant, while subjects harbouring the Gamma variant showed the highest proportion of asymptomatic infection (21.6%), albeit also deaths (5.4%). The Omicron variant was only found in the vaccinated subjects, of which 47% had been hospitalised. The diffusivity and pathogenicity associated with the different SARS-CoV-2 variants are likely to have relevant public health implications, both at the national and international levels. Our study provides data on the rapid changes in the epidemiological landscape of the SARS-CoV-2 variants in Italy.