The current study was conducted to assess whether a single administration of 5‐bromo‐2′‐deoxyuridine (BrdU) interferes with cell proliferation and leads to the activation of apoptotic cellular events ...in the prenatal cerebellum. BrdU effects across a wide range of doses (25–300 μg/g b.w.) were analyzed using immunohistochemical and ultrastructural procedures. The pregnant rats were injected with BrdU at embryonic day 13, and their fetuses were sacrificed from 5 to 35 hr after exposure. The quantification of several parameters such as the density of mitotic figures, and BrdU and proliferating cell nuclear antigen (PCNA)‐reactive cells showed that, in comparison with the saline injected rats, the administration of BrdU impairs the proliferative behavior of neuroepithelial cells. The above‐mentioned parameters were significantly reduced in rats injected with 100 μg/g b.w. of BrdU. The reduction was more evident using 200 μg/g b.w. The most severe effects were found with 300 μg/g b.w. of BrdU. The present findings also revealed that high doses of BrdU lead to the activation of apoptotic cellular events as evidenced by both terminal deoxynucleotidyl transferase dUTP nick‐end labeling (TUNEL) assay and immunohistochemistry for active caspase‐3. In comparison with saline rats, many apoptotic cells were found in rats injected with 100 μg/g b.w. of BrdU. The number of dying cells increased with 200 μg/g b.w. The most important number of apoptotic cells were observed in animals injected with 300 μg/g b.w. of BrdU. Ultrastructural studies confirmed the presence of neuroblasts at different stages of apoptosis.
The present study reveals that low doses of BrdU (from 25 to 75 μg/g) have no deleterious effects on the development of the rat cerebellar neuroepithelium. Our results also denote that the BrdU injection at doses ranging from 100 to 300 μg/g alters neuroblasts proliferation and induces the activation of apoptotic cellular events in the prenatal cerebellum.
Cerebellar neurons are generated from the rhombic lip and the neuroepithelium. In this study, we analyze the histogenesis of the cerebellar neuroepithelium in terms of cellular kinetics. The ...experimental animals are the offspring of pregnant dams injected with 5-bromo-2ʹ-deoxyuridine (BrdU) on embryonic day 13. We infer the fraction of S-phase cells by examining a range of survival times after a single BrdU-exposure and a cumulative BrdU-labeling sequence, which allow for the derivation of cell-cycle parameters and phase durations. The current results indicate that the dose of BrdU employed (35 mg/kg) provides saturation S-phase labeling from at least 1 h after marker delivery. The duration of G2, mitotic phase, and G1 are 1.2, 0.5, and 6.9 h, respectively. The duration for the S-phase, growth fraction, and the whole cycle are obtained on the basis of two proliferative models, steady-state and exponential growth. Both models provided similar results. In conclusion, our results indicate that the steady-state and the cumulative S-phase labeling paradigms can be adopted to analyze cell cycle parameters in the cerebellar neuroepithelium. Current results can help in understanding the regulatory mechanisms of cerebellar histogenesis and the cell biological mechanisms of the proliferative cycle of the neuroepithelium.
In this paper we will analyse how queer gender desires and expressions are cinematically articulated in Lucía Puenzo’s El niño pez. For this purpose, we will study the relationship between Lala (Inés ...Efrón) and her family's Guaraní domestic servant, Ailín (Mariela Vitale). We will implement a methodological approach anchored in the concepts of haptic visuality (Marks 2002) and interseccionality (Crenshaw 1989). Although El niño pezpresents certain identitarian undefinitions linked to queerness, we will demonstrate that the construction of Lala's character points to certain stereotypes related to the filmic representation of lesbianism.
En esta investigación nos fijaremos en cómo se articulan cinematográficamente los deseos y expresiones de género queer en El niño pez de Lucía Puenzo, mediante el análisis de la relación entre Lala (Inés Efrón) y la empleada doméstica guaraní de su familia, Ailín (Mariela Vitale) a través de una metodología anclada en los conceptos de visualidad háptica (Marks 2002) y de interseccionalidad (Crenshaw 1989). Si bien El niño pezpresente ciertas indefiniciones identitarias asociadas a lo queer, se argumentará que la construcción del personaje de Lala apunta a ciertos estereotipos relacionados con la representación fílmica del lesbianismo.
More and more studies indicate that leisure plays a fundamental role in active ageing. Our study describes the current leisure patterns of older adults, comparing them with other age groups. ...Consequently, 445 adults, stratified by age (young, middle-aged and older adults), were selected and subsequently administered a set of tests. The results indicate that older people claim having more time for their leisure activities; however, the diversity of activities performed is lower, showing a negative gradient based on age. The leisure patterns of older people reflect a predominance of passive leisure, little cultural leisure time and moderate levels of social and physical leisure activities. Older people’s leisure seems to be influenced by ageist stereotypes and attribution biases. Our findings imply that these results could be used to design and implement programs aimed at promoting leisure styles that contribute to increase active ageing.
We present a histological study of the cell death of cerebellar neuroepithelial neuroblasts following treatment with the cytotoxic agent hydroxyurea (HU) during the embryonic life. Pregnant rats were ...treated with a single dose of HU (300 mg/kg) at embryonic days 13, 14, or 15 of gestation, and their fetuses were studied from 5 to 35 h after treatment to elucidate the mechanisms of HU-induced fetotoxicity. Quantification of several parameters such as the density of pyknotic, mitotic, and PCNA-immunoreactive cells indicated that HU compromises the survival of the cerebellar neuroepithelium neuroblasts. On the other hand, our light and electron microscopic investigations during the course of prenatal development indicated that HU leads to two types of cell death: apoptosis and cells presenting cytoplasmic vacuolization, altered organelles, and a recognizable cell nucleus. Both modalities of cell death resulted in a substantial loss of cerebellar neuroepithelium cells. Current results suggest that HU exposure during gestation is toxic to the cerebellar neuroepithelium. Moreover, they allow to examine the mechanisms of HU-induced toxicity during the early development of the central nervous system. Our data also suggest that it is essential to avoid underestimating the adverse effects of HU when administered during early prenatal life.
An important step in bromodeoxyuridine (BrdU) immunohistochemistry is the production of single-stranded DNA to make the incorporated BrdU accessible to the antibodies. This paper examines the effect ...of distinct DNA denaturation pretreatments (DNase I, sodium citrate buffer, endonuclease Eco RI and exonuclease III, and HCl hydrolysis) on detection of BrdU. We found that all the methods used in the partial denaturation of DNA combined good nuclear immunostaining with acceptable tissue integrity. We also observed that these immunohistochemical protocols revealed a spatial pattern in the distribution of DNA-synthesizing cells within the cerebellar external granular layer (EGL) of 10-day-old rats, allowing us to estimate the fraction of S-phase cells. Our results indicate that detection of BrdU-stained cells is affected by the distinct histological procedures used in such detection. Additionally, as the duration and phases of the cell cycle in EGL neuroblasts are estimated in accordance with BrdU detection, an effect on this detection can render the measurement of cell cycle inaccurate. The present work shows that DNase I and citrate buffer, at appropriate conditions, may be good alternatives for acid denaturation. However, they are less sensitive than autoradiographic techniques that use
3
H-thymidine administration. Finally, current data reveal that short survival times after a single BrdU exposure do not seem to affect the cell cycle progression of the EGL neuroblasts.
The time courses of apoptosis and autophagy activation were investigated in neuroblasts of the cerebellar external granular layer (EGL) following the treatment with a single dose (2 mg/g) of ...hydroxyurea (HU), a cytotoxic agent. The rats were examined at postnatal day 9 and sacrificed at appropriate times ranging from 10 to 60 h after drug administration. We used the Feulgen method, the TUNEL assay, immunohistochemistry for active caspase-3, and LC3B and p62/SQSTM1 immunoperoxidase procedures. The resulting data indicated that the administration of HU leads to the activation of apoptotic cellular events that began to increase 10 h after HU exposure, peaked at 30 h, and decrease thereafter. It also showed that apoptosis was followed by autophagy activation. Interestingly, LC3B and p62/SQSTM1-stained cells, as well as mitotic cells, started to appear 20 h after the HU injection and their counts increased until 40 h. Afterwards, the values remained stable. The current results highlight an important role of the apoptotic and autophagic processes in the EGL after HU administration. Moreover, they provide a clue for studying the mechanism of chemoresistance triggered by proliferating cells exposed to anticancer agents.
The current paper presents a histological analysis of the cell death in the cerebellar external granular layer (EGL) following the treatment with a single dose (2 mg/g) of hydroxyurea (HU). The rats ...were examined at postnatal days (P) 5, 10, and 15, and sacrificed at appropriate times ranging from 6 to 48 h after treatment administration. Studies were done in each cortical lobe (anterior, central, posterior, and inferior). The quantification of several parameters, such as density of 5-bromo-2′-deoxyuridine, TUNEL, vimentin, and tomato lectin-stained cells, revealed that HU compromises the viability of EGL cells. Our results indicate that P10 is a time of high vulnerability to injury. We also show here that the anterior and central lobes are the cortical regions most susceptible to the action of the HU. Additionally, our data also indicate that from 6 to 24 h after HU-exposure is a time-window of high sensibility to this agent. On the other hand, our ultrastructural analysis confirmed that HU administration produces the activation of apoptotic cellular events in the EGL, resulting in a substantial number of dying cells. Different stages of apoptosis can be observed in all cortical lobes at all investigated postnatal ages and survival times. Moreover, we observed that dying neuroblasts were covered by laminar processes of Bergmann glia, and that these unipolar astrocytes presented cytological features of phagocytes engulfing apoptotic bodies and cell debris. The electron microscopy study also revealed the participation of ameboid microglial cells in the phagocytosis of apoptotic cells in the regions of the EGL with extensive cell death.
Queer teenagers are avid readers of popular culture; as numerous audience studies prove, television plays a significant role in identity-formation for LGBTIQ+ youth, providing them with the ...information about sexuality, gender roles or non-normative relationships usually unavailable in their educational and home environments. In this article we analyze how some of the protagonists of Netflix's TV show 5ex Education (2019-present) utilize popular culture as a tool to explore their desires, forbidden fantasies, and gender expressions, becoming instrumental in the formation of their queer identities in a way that metatextually reflects the role LGBTIQ+ shows play for their audiences. Such is the case of Adam, a bisexual teenager that masturbates to the image of a fictional actor featured in a 1980s action film poster; Lily, whose sexual fantasies of role playing with alien creatures are strongly influenced by spatial sci-fi; and Ola, whose onyric universe is influenced by David Bowie's genderbending aesthetics. However, the most representative example of how popular culture influences the formation of queer identities is Eric, whose non-conforming gender expression follows the example set by the trans characters in Hedwig and the Angry Inch.
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