Abstract Estimation of the time since death is important in forensic medicine, and so far not much is known in employing dental pulp for such purposes. The tooth organ is the hardest organ in the ...human body, with a loose connective tissue of dental pulp situated within a rigid encasement of mineralized surrounding tissues. Human material was obtained from 31 corpses of people who died in car and train accidents and had healthy oral statuses. Samples were divided into two groups at different environmental temperatures. During the autopsy, the jaws were resected to keep teeth in situ , and every day one tooth was extracted. After decalcification, serial thin sections stained with hematoxylin and eosin were cut. Odontoblasts in the dental pulp were counted and data analysed. Statistical analysis showed that the number of odontoblasts drops during the time after death, and no odontoblasts remain in the pulp after 5 days.
The motor neurons and skeletal muscle fibers they innervate are strongly dependent on each other. Important communication between both tissues is mediated through the neuromuscular junction. However, ...release and reception of various factors at other parts of both tissues must also be considered as means of mutual influences. In vitro innervated human muscle is the only experimental model to investigate nerve - muscle interactions during synaptogenesis of human neuromuscular junction. Here we studied the occurrence of programmed cell death in this model. In order to find out if mutual interactions between neurons and myotubes control the extent of apoptosis in both tissues, we compared the number of apoptotic cells in spinal cord explants and myotubes in co-cultures and mono-cultures of these tissues. Apoptotic cells were detected by TUNEL at selected time intervals (10, 21 and 30 days after co-culture) coresponding to various stages of synaptogenesis of neuromuscular junction. The number of apoptotic cells in spinal cord explants was higher at earlier (day 10) in comparison to later stages (days 21 and 30). Co-cultures and mono-cultures did not differ in this respect. TUNEL positive cells were not found in mono-cultured human myotubes under our experimental conditions. These results suggest that the process of apoptosis seems to be rather independent on neuron - muscle interactions at least at the time points examine.
Germ cell apoptosis in the human testis Martincic, D S; Virant Klun, I; Zorn, B ...
Pflügers Archiv,
01/2001, Letnik:
442, Številka:
6 Suppl 1
Journal Article
Recenzirano
Apoptosis is a widespread phenomena during development. It represents a form of cell death and has a crucial role in tissue homeostasis. Apoptosis is also involved in a number of pathological ...conditions. Spermatogenesis is a dynamic process of germ cell proliferation and differentiation. During regular spermatogenesis, the number of testicular germ cells degenerate by an apoptotic process. The significance of regulating cell population by apoptosis is more apparent when sperm production is halted. The presence and frequency of apoptosis in germ cells of human testis biopsy specimens were tested. The results confirm the presence of germ cell apoptosis but not the apoptosis of Sertoli cells. The increased apoptotic index was observed in patients with azoospermia in comparison with normal but obstructed spermatogenesis.
Little is known about the transcriptional regulators that control the proliferation of multipotent bone marrow progenitors. Understanding the mechanisms that restrict proliferation is of significant ...interest since the loss of cell cycle integrity can be associated with hematopoietic exhaustion, bone marrow failure, or even oncogenic transformation. Herein, we show that multipotent LSKs (lineage(-)Sca(high)c-kit(+)) from E47-deficient mice exhibit a striking hyperproliferation associated with a loss of cell cycle quiescence and increased susceptibility to in vivo challenge with a mitotoxic drug. Total LSKs contain long-term self-renewing hematopoietic stem cells and downstream multipotential progenitors (MPPs) that possess very limited or no self-renewal ability. Within total LSKs, we found specific developmental and functional deficits in the MPP subset. E47 knockout mice have grossly normal numbers of self-renewing hematopoietic stem cells but a 50-70% reduction in nonrenewing MPPs and downstream lineage-restricted populations. The residual MPPs in E47 knockout mice fail to fully up-regulate flk2 or initiate V(D)J recombination, hallmarks of normal lymphoid lineage progression. Consistent with the loss of normal cell cycle restraints, we show that E47-deficient LSKs have a 50% decrease in p21, a cell cycle inhibitor and known regulator of LSK proliferation. Moreover, enforced expression studies identify p21 as an E47 target gene in primary bone marrow LSKs. Thus, E47 appears to regulate the developmental and functional integrity of early hematopoietic subsets in part through effects on p21-mediated cell cycle quiescence.
Apoptosis associated with programmed cell death plays an essential role in the control of germ cell number in the testes. Although male germ cell apoptosis has been well characterized in different ...animal models, only a few studies of apoptosis in human testes are presently available. In 43 infertile men with azoospermia of varying aetiology, testicular tissue was obtained by testicular biopsy. Apoptosis of testicular germ cells was determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling method in situ. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive cells were found in the testicular tissue of all patients with azoospermia, except in Sertoli cell-only syndrome. The apoptotic index was higher in germ cell hypoplasia and in normal spermatogenesis in comparison with germ cell arrest. This study was performed to confirm the presence and determine the frequency of apoptosis in infertile men.
Microfluidic reagent-based nutrient sensors offer a promising technology to address the global undersampling of ocean chemistry but have so far not been shown to operate in the deep sea (>200 m). We ...report a new family of miniaturized lab-on-chip (LOC) colorimetric analyzers making in situ nitrate and phosphate measurements from the surface ocean to the deep sea (>4800 m). This new technology gives users a new low-cost, high-performance tool for measuring chemistry in hyperbaric environments. Using a combination of laboratory verification and field-based tests, we demonstrate that the analyzers are capable of in situ measurements during profiling that are comparable to laboratory-based analyses. The sensors feature a novel and efficient inertial-flow mixer that increases the mixing efficiency and reduces the back pressure and flushing time compared to a previously used serpentine mixing channel. Four separate replicate units of the nitrate and phosphate sensor were calibrated in the laboratory and showed an average limit of detection of 0.03 μM for nitrate and 0.016 μM for phosphate. Three on-chip optical absorption cell lengths provide a large linear range (to >750 μM (10.5 mg/L-N) for nitrate and >15 μM (0.47 mg/L-P) for phosphate), making the instruments suitable for typical concentrations in both ocean and freshwater aquatic environments. The LOC systems automatically collected a series of deep-sea nitrate and phosphate profiles in the northeast Atlantic while attached to a conductivity temperature depth (CTD) rosette, and the LOC nitrate sensor was attached to a PROVOR profiling float to conduct automated nitrate profiles in the Mediterranean Sea.
Why is the Winner the Best? Reinke, A.; Tizabi, M. D.; Isensee, F. ...
2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR),
2023-June
Conference Proceeding
Odprti dostop
International benchmarking competitions have become fundamental for the comparative performance assessment of image analysis methods. However, little attention has been given to investigating what ...can be learnt from these competitions. Do they really generate scientific progress? What are common and successful participation strategies? What makes a solution superior to a competing method? To address this gap in the literature, we performed a multicenter study with all 80 competitions that were conducted in the scope of IEEE ISBI 2021 and MICCAI 2021. Statistical analyses performed based on comprehensive descriptions of the submitted algorithms linked to their rank as well as the underlying participation strategies revealed common characteristics of winning solutions. These typically include the use of multi-task learning (63%) and/or multi-stage pipelines (61%), and a focus on augmentation (100%), image preprocessing (97%), data curation (79%), and post-processing (66%). The "typical" lead of a winning team is a computer scientist with a doctoral degree, five years of experience in biomedical image analysis, and four years of experience in deep learning. Two core general development strategies stood out for highly-ranked teams: the reflection of the metrics in the method design and the focus on analyzing and handling failure cases. According to the organizers, 43% of the winning algorithms exceeded the state of the art but only 11% completely solved the respective domain problem. The insights of our study could help researchers (1) improve algorithm development strategies when approaching new problems, and (2) focus on open research questions revealed by this work.
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