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[en] Full text: The numbers of X-chromatin body ('drumstick' appendages) in the interphase nuclei of three major breeds of Nigerian goats were studied. Each goat breed was derived from three different locations in the country based on the areas of its preponderance. Smears from buccal cavity and PMNS of each goat were developed using standard staining techniques. The mean values obtained per breed irrespective of sex were 1.92%, 1.65% and 1.60% for Sahel Goats (SG), Red Sokoto Goats (RSG) and West African Dwarf Goats (WADG), respectively. The mean value obtained for the bucks and does irrespective of breed were 0.13% and 3.07%, respectively. Those for males per breed were 0.15% for SG, 0.15% for RSG, and 0.10% for WADG and for does per breed were: 3.44% for SG, 3.10% for RSG and 2.67% for WADG. The results generally revealed that the frequency of 'drumstick' was statistically different (P < 0.05) between Bucks and Does; Bucks were statistically the same (P < 0.05) in 'drumstick' incidence, irrespective of breed and location, while the 'drumstick' incidence was statistically higher (P < 0.05) in Sahelian Does, followed by RS Does and least in WAD Does. This may account for higher prolificacy frequently observed in SG, followed by RSG. However, location exhibited an infinitesimal effect on the frequency of 'drumstick' within breeds, indicating that incidence of 'drumstick' is purely a genetic factor. (author)
[en] Fertilization and early embryogenesis has been studied in an aquatic heterosporic Fern: Marsilea vestita. The sperm penetration and the evolution of the male genetic material in the fermale nucleoplasm has been followed by autoradiographic techniques with the use of a specific DNA precursor. The male chromatin remains in a limited space of the female nucleoplasm and mixes gradualy during early embryogenesis. A very slow fusion has been found in the cells which will become the apical cells of each functional radicular, foliar and shoot meristems. Concerning the cytoplasmic organelles, the problem is still unresolved but the results obtained by high autoradiographic resolution show that the paternal organelles perhaps partially participate in the organisation of the embryo cytoplasmic genomes
[fr]On a etudie la fecondation et le debut de l'embryogenese chez une fougere heterosporee: Marsilea vestita. La penetration du sperme et l'evolution du materiel genetique du male dans le nucleoplasme de la femelle ont ete suivis par des techniques autoradiographiques en utilisant un precurseur specifique de l'ADN. La chromatine male reste dans un espace limite du nucleoplasme de la femelle et se melange graduellement durant l'embryogenese. Ce processus est nettement differe dans certains groupes cellulaires qui ont des positions annoncant celles des cellules initiales des trois meristemes de l'embryon, foliaire, radiculaire et caulinaire. Concernant les organites cytoplasmiques, le probleme n'est toujours pas resolu, mais les resultats obtenus par autoradiographie a haute resolution montrent que la participation d'organites paternels du genome de l'embryon n'est pas a ecarter
[en] Chemical fixation is nearly indispensable in the biological sciences, especially in circumstances where cryo-fixation is not applicable. While universally employed for the preservation of cell organization, chemical fixatives often introduce artifacts that can confound identification of true structures. Since biological research is increasingly probing ever-finer details of the cellular architecture, it is critical to understand the nanoscale transformation of the cellular organization due to fixation both systematically and quantitatively. In this work, we employed Partial Wave Spectroscopic (PWS) Microscopy, a nanoscale sensitive and label-free live cell spectroscopic-imaging technique, to analyze the effects of the fixation process through three commonly used fixation protocols for cells in vitro. In each method investigated, we detected dramatic difference in both nuclear and cytoplasmic nanoarchitecture between live and fixed states. But significantly, despite the alterations in cellular nanoscale organizations after chemical fixation, the population differences in chromatin structure (e.g. induced by a specific chemotherapeutic agent) remains. In conclusion, we demonstrated that the nanoscale cellular arrangement observed in fixed cells was fundamentally divorced from that in live cells, thus the quantitative analysis is only meaningful on the population level. This finding highlights the importance of live cell imaging techniques with nanoscale sensitivity or cryo-fixation in the interrogation of cellular structure, to complement more traditional chemical fixation methods. - Highlights: • PWS was employed to monitor fixation process for the same cells in vitro. • Dramatic changes in cellular nanostructure were observed after fixation. • However, the population difference of chromatin structure remains after fixation.
[en] Transcriptionally active chromatin fibers were observed in chromosomes presenting the loops/scaffold configuration. The active fibers showed altered nucleosomes and presented multiforked aspects which led to the formation of ring complexes. The ribonucleoprotein transcripts (RNP) appeared as networks of 0.1 μm or multiples tandemly disposed along the fiber. It is suggested that the ring complexes belong to the human genome. The possibility that these circular structures come from a prokaryote is also considered. (author)
[pt]Fibras de cromatina ativas em transcricao foram observadas em cromossomos humanos. Esses cromossomos mostram configuracoes do tipo ''loops/scaffold''. As fibras ativas tem nucleossomos alterados e apresentam aspectos ''multi-forked'' os quais levam a formacao de aneis. Os transcritos de Ribonucleoproteina (RNP) aparecem como emaranhados de 0,1 μm ou multiplos dispostos em serie ao longo de fibra. Sugere-se que os complexes circulares de cromatina pertencem ao genoma humano. A possibilidade de que os aneis provem de procariotos e tambem discutida. (autor)
[en] CUL4A; an E3 ubiquitin ligase is involved in the degradation of negative regulators of cell cycle such as p21, p27, p53, etc., through polyubiquitination-mediated protein degradation. The functional role(s) of CUL4A proteins on their targets are well characterized; however, the transcriptional regulation of CUL4A, particularly at its promoter level is not yet studied. Therefore, in this study, using computational tools, we found cAMP responsive elements (CRE) at the locations of − 926 and − 764 with respect to transcription state site + 1 of CUL4A promoter. Hence, we investigated the role of CREB on the regulation of CUL4A transcription. Our chromatin immunoprecipitation (ChIP) data clearly showed increased levels of promoter occupancy of both CREB and pCREB on both CREs of CUL4A promoter. As expected, the expression of CUL4A increases and decreases upon the overexpression of and knocking down of CREB, respectively. Moreover, the inhibition of ERK pathway by U0126 not only reduces the CREB activation but also the CUL4A levels suggesting that CREB is the upstream activator of CUL4A transcription. The reduction of CUL4A levels upon the knocking down of CREB or by U0126 treatment increases the protein levels of CUL4A substrates such as p21 and p27. It is reported that CUL4A activates the ERK1/2 transcription and ERK1/2 pathway activates the CREB by phosphorylation. Based on our data and earlier findings, we report that CREB regulates the CUL4A levels positively which in turn activates the CREB through ERK1/2 pathway in the form of auto-regulatory looped mechanism.This suggests that CUL4A might be involved in proliferation of cancer cells by regulating the ERK1/2 and CREB signaling.
[en] Infantile hemangiomas are the most frequent vascular soft tissue lumps in the pediatric population. The clinical presentation and evolution of these lesions is characteristic, while the sonographic appearance is classic but not specific. This pictorial essay illustrates the different vascular soft tissue lumps on ultrasound that may mimic infantile hemangiomas. Awareness of these mimics is crucial to avoid misdiagnosis. Clinical and sonographic discriminators for each lesion are presented. (author)
[en] An eight week trial, involving superficial hyperthermia delivered biweekly via simple water bath immersion, was tested for its ability to clear mild to moderate psoriatic lesions. Seven patients were treated and three cases rapidly improved. In the remaining patients, the treatment frequency was increased to alternate days; two cases improved significantly, one patient showed a partial response, and the fourth had no visible change (this was the only patient taking concurrent drug therapy - etretinate). In addition to resolving psoriatic lesions, water bath hyperthermia also reduced edema (swelling) and relieved pruritus (itching) in all patients, both during the treatment period and for up to several months after lesions had returned. Lesion reappearance occurred within one to three months after the last heat treatment. We retreated one patient and produced a second complete remission. These results indicate that simple repetitive water bath hyperthermia alone is effective in the treatment of psoriatic lesions in heatable locations. An unexpected side effect was enhanced melanin content (tanning) in all areas where hyperthermia treated skin was exposed to sunlight. (author)
[en] Radiation necrosis (RN) may closely mimic tumor progression or recurrence (TPR) in its clinical presentation and imaging findings in brain tumor patients. In this issue, Korchi et al describe imaging appearances of five consecutive cases of RN from 73 skull-based tumors treated with proton-beam radiotherapy (RT) in Switzerland. An important feature of this study is the selection of patients with extra-axial tumors that tend to recur locally. As such, intra-axial lesions detected following RT more likely represent radiation injury rather than TPR - an interesting model to study imaging findings of RN. Their findings are concordant with those seen with photon RT suggesting that the process of RN may be partly independent of underlying pathology and radiation modality. This study, however, does not help us understand how to distinguish these lesions from TPR. (author)