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.
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.
Over the 15th century the city of Valencia was shaped as a very important emporium that drew business, goods and some people too. Valencia became a great cosmopolitan centre where merchants and ...artisans from all the European continent could carry out their works. We document the presence of Venetians in the city of Valencia during the first half of the 15th century. We can observe their commercial activities (freight, wool and slave trade) and their low level of settlement. The novelty lies in the fact that it is a lesser-known chronological period that connects with the arrival of the mude in Valencia.
En el transcurso del siglo XV, la ciudad de Valencia se configuró como un importante emporio comercial que atrajo negocios, mercancías, y también personas. Valencia fue un gran centro cosmopolita donde comerciantes y artesanos de toda la geografía europea podían desarrollar sus actividades. Documentamos la presencia de venecianos en la ciudad de Valencia durante la primera mitad del siglo XV. Podemos observar sus actividades mercantiles (fletes, comercio de lanas y esclavos) y su escaso nivel de asentamiento. La novedad radica en que se trata de un período cronológico menos conocido que entronca con la llegada de las mude a Valencia.
The mechanisms and causes of the sudden failure of the Aznalcóllar tailings pond were investigated. The dam underwent displacements of up to 55 m along a 700 m length, releasing large quantities of ...acidic waters and 5.5 million m
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of pyrite and pyroclastic tailings. It was a progressive type of failure, allowed by the brittle response of the pre-consolidated and cemented Guadalquivir blue clays and the high pore pressures left from the incomplete consolidation of the dam’s foundation. Special modelling difficulties were posed by the need to incorporate the strain softening behaviour of the clays. The results show that although the timing of the failure could have been approximated using equivalent ductile properties, predicting the shallow, planar geometry of the failure surface observed would have required a precise representation of the brittle response. The failure triggered liquefaction of the tailings, which accelerated at more than 0.1 g. This transition was modelled by migrating from a coupled effective stress approach employing implicit integration to a total stress formulation using an explicit solver.
Abstract This is a first attempt to examine the dynamic second-hand arms and harnesses market. Furthermore, inventories of private arsenals offer interesting data concerning the status and social ...perception regarding the ownership of these arms. E si aquelles de aigu seran dÛtes de la orado avant, que aquell aytal perda les dites armes e sia mes en la presó de la dita ciutat, estiga a mercé del dit senyor comte, havent per revocades qualsevol licencies de dur armes per lo dit senyor comte atorgades, corn sia voler del dit senyor aquelles haver per revocades manant ab la present a tots e sengles hostalers que la present intimen e notifiquen als venints posar a Ilurs hostals, e aço sots pena de XX sous, intimant a cuyt en general, e a cascú en special totes les damunt dites coses e sengles, a fi que per algú ignorancia no puixa ésser allegada. En los testimonios abundarán las amenazas de muerte, las heridas y golpes, la resistencia ante la autoridad, e incluso el encarcelamiento.8 Y es que esas luchas, que aúnan formas de violencia entre privados, pueden ir desde el asesinato individualizado hasta enfrentamientos más onerosos, lo que en definitiva facilitaba el uso de armas entre particulares (Etxeberria y Fernández, 2022).
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
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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.
Childhood and adolescence represent a vital period in the formation of the individual's personality. If that period can already be hard and traumatic according to certain times, it can be even more ...so if the actors in the process are orphans. We present here a contextualization about the life of the orphans of the Maestrazgo de Montesa in Castellon during the Middle Ages. For this we use the notarial records kept in the area. Of all the documentation consulted, we make special mention of the guardianships because they offer indicative data on how the life of these young people developed until they reached the legal age of majority.
Resumen: La infancia y la adolescencia suponen un período vital en la formación de la personalidad del individuo. Si ese período ya puede resultar duro y traumático según determinadas épocas, aún lo puede ser más si los actores del proceso son huérfanos. Presentamos aquí una contextualización sobre la vida de los huérfanos del territorio castellonense del Maestrazgo de Montesa durante la Edad Media. Para ello utilizamos los registros notariales conservados en la zona. De toda la documentación consultada hacemos especial mención a las tutelas porque ofrecen datos indiciarios sobre cómo se desarrolló la vida de esos jóvenes hasta alcanzar la mayoría de edad legal.
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