Passive immunotherapy with convalescent COVID-19 plasma (CCP) is used as a therapeutic procedure in many countries, including Serbia. In this study, we analyzed the association between demographic factors, COVID-19 severity and the reactivity of anti-SARS-CoV-2 antibodies (Abs) in Serbian CCP donors. Individuals (n = 468) recovered from confirmed SARS-CoV-2 infection, and who were willing to donate their plasma for passive immunization of COVID-19 patients were enrolled in the study. Plasma samples were tested for the presence of IgG reactive to SARS-CoV-2 spike glycoprotein (S1) and nucleocapsid antigens. Individuals were characterized according to age, gender, comorbidities, COVID-19 severity, ABO blood type and RhD factor. Total of 420 candidates (420/468; 89.74%) reached the levels of anti-SARS-CoV-2 IgG that qualified them for inclusion in CCP donation program. Further statistical analysis showed that male individuals (p = 0.034), older age groups (p < 0.001), existence of hypertension (p = 0.008), and severe COVID-19 (p = 0.000) are linked with higher levels of anti-SARS-CoV-2 Abs. These findings will guide the selection of CCP donors in Serbia. Further studies need to be conducted to assess the neutralization potency and clinical efficiency of CCP collected from Serbian donors with high anti-SARS-CoV-2 IgG reactivity.

A radioimmunoassay was validated to measure faecal oestrogen and progesterone metabolites in captive female North American porcupines (Erethizon dorsatum) (n = 5) for a period of between 261-393 days. Females housed alone (n = 3) exhibited fluctuations in faecal oestrogens indicative of follicular activity, yet these solitary females did not ovulate spontaneously. Breeding females (n = 2) appeared to experience pscudopregnancy lasting for approximately 87 and 112 days. In the single successful birth, gestation was 135 days. Faecal progestagen concentrations in breeding females were twice that of non-breeding females, however, occasional overlap between pregnant and non-pregnant hormone concentrations precluded the use of faecal steroids as an index of pregnancy status. These preliminary data suggest that noninvasive faecal steroid monitoring is a useful tool for evaluating longitudinal reproductive-endocrine rhythms in porcupines.Resume. -Analyse des fluctuations des taux d'oestrogene et de progesterone fecaux chez des fcmclles reproductrices et non rcproductrices du Pore-epic nord-americain (Erethizon dorsatum). Un dosage par radioimmunologie a etc mis au point dans le but de mesurer les variations de concentrations de metabolites d'ocstrogene et de progesterone chez des femelles captives du Pore-epic nord americain, sur une periode de 261 a 393 jours. Les fluctuations des taux d'ocstrogenes fecaux des femelles maintenues isolees (n = 3) marquent une activite folliculaire, bien que ces femelles solitaires ne presentcnt pas une ovulation spontanee. Les fluctuations d'hormones chez des fcmclles reproductrices (n = 2) suggerent quc ces derniercs presentent une pseudogcstation dont la duree varic de 87 ä 112 jours. Dans le seul cas de mise-bas reussie, la gestation avait dure 135 jours. Les concentrations de progesterone fecale chez les femelles reproductrices etaient deux fois plus importantes que chez les non reproductrices. Toutefois, la superposition occasionnelle cntre les prof us des deux types dc femelles rend difficile utilisation des stero'ides fecaux commc indice de gestation. Ces resultats prcliminaircs suggerent que le suivi non invasif des stero'idcs fecaux peut etre un bon outil devaluation des rythmcs longitudinaux endocriniens de la reproduction chez le Pore-epic nord-americain.

Introduction: Stress represents a set of reactions in the organism activated by external factors. In order to maintain homeostasis and protect the organism, numerous mechanisms for adaptation to stress evolved. Stressors that act in short-term period cause acute stress reaction with generally positive effect on organism. When the stressor persists, and the organism fails to respond to the challenge, chronic stress develops, leading to pathological conditions, such as women's menstrual cycle disorders. Aim: To examine the impact of chronic restraint stress on the estrous cycle in NMRI female mice. Material and methods: A number of 12 mature female NMRI mice were randomly divided into control (n = 6) and experimental (n = 6) group. The induction of stress was performed for the experimental group by using restrain chambers 2 hours daily in 14 days. From the beginning of the experiment, vaginal lavages were taken from all mice for making smears that were analyzed to determine estrous cycle stages. For analysis of chronic stress effect, the frequency of estrus stages alternation observed in experimental group compared to control was examined. Results: The estrous cycle was observed and divided into proestrus, estrus, metestrus and diestrus. During the adaptation period, prolonged diestrus was dominantly present in both groups. When stress was induced, in the experimental group animals the absence of diestrus stage and oscillation to other stages was obseved, in contrast to the control group, where the diestus stage was frequently observed. Frequency of diestrus stage deviation in stressed animals was shown to be statistically significant (p < 0.01) when compared to control. Conclusion: The induction of chronic restraint stress in female NMRI mice leads to the alternation of the estrous cycle. Considering the fact that NMRI female mice share the similar hormonal regulation of the estrous cycle with women's menstrual cycle, they could present a solid model for studying women's reproductive disorders.

Introduction: A broad spectrum of research involving stress and stress protocols has long proven that a point of anhedonia, social defeat and learned helplessness can be achieved and observed – with anhedonia being a clinical symptom of Anxiety, Depression and Bipolar Affective Disorder. Aim: The aim of this study is the development of a simplified protocol for anhedonia induction in NMRI male mice in order to shorten the period of mice suffering and decrease complexity of the procedure for other researchers and introduction of new parameter in order to achieve better standardization of results. Materials and Methods: 21 male NMRI mice were introduced to 2 different stress protocols (one found in literature and one simplified) where cognitive- behavioral status was tested using the Sucrose Preference Test, Open Field Test, Grooming Pattern and histological examination of adrenal glands, and to propose a new protocol for fellow researchers. Results: Results observed include the successful induction of anhedonia proven by Sucrose Preference Tests, Barbering effect and microhemorrhage of the adrenal glands. Simplified protocol showed superiority compared to the one found in literature. Conclusion: Simplified protocol showed higher efficiency and reduced amount of work during testing phase. Introduction of NMI as a new parameter during behavioral evaluation resulted in better standardization of measured SPT values that incorporates common knowledge of mammal physiology. A big developmental step was the introduction of the Normalised Mass Index to even out mass fluctuations and differences in basal metabolism, which we recommend to other researchers and institutions.