The neonatal southern white rhinoceros ovary contains oogonia in germ cell nests.

The northern white rhinoceros is functionally extinct with only two females left. Establishing methods to culture ovarian tissues, follicles, and oocytes to generate eggs will support conservation efforts using in vitro embryo production. To the best of our knowledge, this is the first description of the structure and molecular signature of any rhinoceros, more specifically, we describe the neonatal and adult southern white rhinoceros (Ceratotherium simum simum) ovary; the closest relation of the northern white rhinoceros. Interestingly, all ovaries contain follicles despite advanced age. Analysis of the neonate reveals a population of cells molecularly characterised as mitotically active, pluripotent with germ cell properties. These results indicate that unusually, the neonatal ovary still contains oogonia in germ cell nests at birth, providing an opportunity for fertility preservation. Therefore, utilising ovaries from stillborn and adult rhinoceros can provide cells for advanced assisted reproductive technologies and investigating the neonatal ovaries of other endangered species is crucial for conservation.

Variation in follicle health and development in cultured cryopreserved ovarian cortical tissue: a study of ovarian tissue from patients undergoing fertility preservation.

This study investigated how follicle health and development in human ovarian tissue cryopreserved for fertility preservation varied between patients before and after 6 d of in vitro culture. Ovarian tissue from 12 patients (9-25 years) was used. In 3 patients, a 1hr neutral red (NR) incubation was used to identify tissues with viable follicles. Tissues were fixed, sectioned and follicles staged and graded for health. Inter-patient differences were observed in the non-cultured tissue in the number of both healthy follicles (p = 0.005) and growing follicles (p = 0.005). After culture there was significant variation in the number of transitional, primary and secondary follicles between patients (p < 0.001). Asymmetric primary follicles with a single complete layer of granulosa cells plus two or more additional partial layers were 5.5 times more likely to be observed in cultured compared to non-cultured tissue (p = 0.0063). Non-cultured (p = 0.0125) and cultured (p < 0.001) tissue selected using NR had more healthy follicles compared to tissue not selected using NR. Non-cultured and cultured tissue selected using NR had more healthy follicles compared to tissue not selected using NR (p = 0.0125; p < 0.001). We demonstrate that inter-patient variation exists in the health and development of follicles before and after culture. Culture systems need to be optimized to support cryopreserved ovarian tissue and these findings should prompt researchers to consider patient variation when evaluating culture systems.

Analysing culture methods of frozen human ovarian tissue to improve follicle survival.

In vitro follicle growth is a potential fertility preservation method for patients for whom current methods are contraindicated. Currently, this method has only been successful using fresh ovarian tissue. Since many patients who may benefit from this treatment currently have cryopreserved ovarian tissue in storage, optimising in vitro follicle growth (IVG) for cryopreserved-thawed tissue is critical. This study sought to improve the first step of IVG by comparing different short-term culture systems for cryopreserved-thawed human ovarian tissue, in order to yield a higher number of healthy multilayer follicles. We compared two commonly used culture media (αMEM and McCoy's 5A), and three plate conditions (300 µL, 1 mL on a polycarbonate membrane and 1 mL in a gas-permeable plate) on the health and development of follicles after 6 days of culture. A total of 5797 follicles from three post-pubertal patients (aged 21.3 ± 2.3 years) were analysed across six different culture conditions and non-cultured control. All culture systems supported follicle development and there was no difference in developmental progression between the different conditions tested. Differences in follicle morphology were evident with follicles cultured in low volume conditions having significantly greater odds of being graded as morphologically normal compared to other conditions. Furthermore, culture in a low volume of αMEM resulted in the highest proportion of morphologically normal primary and multilayer follicles (23.8% compared to 6.3-19.9% depending on condition). We, therefore, recommend culturing cryopreserved human ovarian tissue in a low volume of αMEM to support follicle health and development. LAY SUMMARY: Ovaries contain a large number of follicles, each containing an immature egg and other important cells. Cancer treatments can lead to long-lasting negative side effects to the ovaries including the destruction of follicles, resulting in infertility. One strategy to preserve fertility is freezing of ovaries or ovarian tissue in girls and women undergoing cancer treatment. The long-term aim is to thaw and grow their ovarian tissue in the laboratory to obtain mature eggs, which can then be fertilised. In this study, we compared six different methods of growing previously frozen human ovarian tissue in order to best support follicle growth and health. We found that using the lowest amount of αMEM medium (a specific type of nutrient-rich growth solution) resulted in the highest proportion of healthy follicles. Improving the methods used to grow ovarian tissue, particularly frozen tissue, is important for future fertility preservation.

RPR 119990, a novel alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid antagonist: synthesis, pharmacological properties, and activity in an animal model of amyotrophic lateral sclerosis.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonists are of potential interest for the treatment of certain acute and chronic neurodegenerative diseases, including amyotrophic lateral sclerosis. Here, we describe the synthesis and pharmacological properties of 9-carboxymethyl-4-oxo-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-2-phosphonic acid (RPR 119990). The compound displaced [3H]AMPA from rat cortex membranes with a K(i) of 107 nM. In oocytes expressing human recombinant AMPA receptors, RPR 119990 depressed ion flux with a K(B) of 71 nM. The antagonist properties of this compound were confirmed on rat native AMPA receptors in cerebella granule neurons in culture and in hippocampal slices where it antagonized electrophysiological responses with IC50 values of 50 and 93 nM, respectively. RPR 119990 antagonized hippocampal evoked responses in vivo, demonstrating brain penetration at active concentrations. RPR 119990 is a potent anticonvulsant in the supramaximal electroshock in the mouse with an ED50 of 2.3 mg/kg 1 h post s.c. administration, giving it a workably long action. Pharmacokinetic studies show good passage into the plasma after subcutaneous administration, whereas brain penetration is low but with slow elimination. This compound was found active in a transgenic mouse model of familial amyotrophic lateral sclerosis (SOD1-G93A) where it was able to improve grip muscle strength and glutamate uptake from spinal synaptosomal preparations, and prolong survival with a daily dose of 3 mg/kg s.c.

Sleep alterations in experimental street rabies virus infection occur in the absence of major EEG abnormalities.

Brain electrical activity and sleep organization were investigated in chronically implanted mice during street rabies virus infection. Continuous EEG recordings showed no gross electrical abnormalities until a few hours before the fatal issue. In contrast, alterations of sleep stages were observed at an early stage during the course of rabies virus infection, at a time when clinical signs were absent. Quantification by spectral analysis showed that the main feature was the early decrease of REM-sleep stages and the increase of the duration of waking stages. Neuromuscular disorders which could occur early were also observed during the disease. Comparison of these data with those obtained from fixed rabies virus infection shows that in the latter the EEG recordings demonstrated early alterations and a progressive deterioration with disappearance of both sleep and waking stages, which were replaced by a pathological sleep stage. In order to evaluate the potential role of the host-specific immune response in promoting brain electrophysiological alterations, EEG recordings and spectral analysis were also performed in cyclophosphamide-treated mice. Street rabies virus-infected and immunosuppressed mice showed identical physiopathological changes as those observed in immunocompetent mice. The implication of these viral-induced electrophysiological alterations in the context of the pathogenic mechanisms of rabies virus is discussed.

Electrophysiological and sleep alterations in experimental mouse rabies.

Changes in the spontaneous brain electrical activity and sleep organization were investigated in 5 mice strains during the evolution of experimental fixed rabies infection. Cortical electrodes were chronically implanted for continuous EEG recording and spectral analysis until death. Three evolutionary phases were individualized. The initial phase exhibited alterations of sleep stages, REM sleep disappearance, pseudoperiodic facial myoclonus and first clinical signs. The mature phase was characterized by a generalized EEG slowing (2-4 cycles/s). The terminal phase occurring with extinction of hippocampal rhythmic slow activity showed a flattening of cortical activity. The brain electrical activity ceased about 30 min before the cardiac arrest. Paroxysmal activities appeared during the course of the disease as bursts of rhythmic slow waves, pseudoperiodic spikes or occasionally ictal epileptic discharges. Spectral analysis revealed a progressive and characteristic clustering of the EEG frequency band power values. The spread of infection in the CNS was monitored by specific immunofluorescence studies which revealed the presence of rabies virus antigen in the pons, the cerebellum, the thalamus and the cortex during the initial phase. The pyramidal field of the hippocampus was infected during the mature phase but the gyrus dentatus was never infected even at the terminal phase. These studies show that particular neuronal functions are impaired during rabies virus infection suggesting that neuronal alterations may be involved in the pathogenic mechanisms leading to lethality.