Reduction of Microvessel Number and Length in the Cerebellum of Purkinje Cell Degeneration Mice.

Degenerative effects of nerve tissues are often accompanied by changes in vascularization. In this regard, knowledge about hereditary cerebellar degeneration is limited. In this study, we compared the vascularity of the individual cerebellar components of 3-month-old wild-type mice (n = 8) and Purkinje cell degeneration (pcd) mutant mice, which represent a model of hereditary cerebellar degeneration (n = 8). Systematic random samples of tissue sections were processed, and laminin was immunostained to visualize microvessels. A computer-assisted stereology system was used to quantify microvessel parameters including total number, total length, and associated densities in cerebellar layers. Our results in pcd mice revealed a 45% (p < 0.01) reduction in the total volume of the cerebellum, a 28% (p < 0.05) reduction in the total number of vessels and a lower total length, approaching 50% (p < 0.001), compared to the control mice. In pcd mutants, cerebellar degeneration is accompanied by significant reduction in the microvascular network that is proportional to the cerebellar volume reduction therefore does not change density of in the cerebellar gray matter of pcd mice.

Quantification of Solid Embryonic Cerebellar Graft Volume in a Degenerative Ataxia Model.

Substitution of lost neurons by neurotransplantation would be a possible management of advanced degenerative cerebellar ataxias in which insufficient cerebellar reserve remains. In this study, we examined the volume and structure of solid embryonic cerebellar grafts in adult Lurcher mice, a model of olivocerebellar degeneration, and their healthy littermates. Grafts taken from enhanced green fluorescent protein (EGFP)-positive embryos were injected into the cerebellum of host mice. Two or six months later, the brains were examined histologically. The grafts were identified according to the EGFP fluorescence in frozen sections and their volumes were estimated using the Cavalieri principle. For gross histological evaluation, graft-containing slices were processed using Nissl and hematoxylin-eosin staining. Adjustment of the volume estimation approach suggested that it is reasonable to use all sections without sampling, but that calculation of values for up to 20% of lost section using linear interpolation does not constitute substantial error. Mean graft volume was smaller in Lurchers than in healthy mice when examined 6 months after the transplantation. We observed almost no signs of graft destruction. In some cases, compact grafts disorganized the structure of the host's cerebellar cortex. In Lurchers, the grafts had a limited contact with the host's cerebellum. Also, graft size was of greater variability in Lurchers than in healthy mice. The results are in compliance with our previous findings that Lurcher phenotype-associated factors have a negative effect on graft development. These factors can hypothetically include cerebellar morphology, local tissue milieu, or systemic factors such as immune system abnormalities.

Exposure to alternative bisphenols BPS and BPF through breast milk: Noxious heritage effect during nursing associated with idiopathic infertility.

There is increasing evidence that bisphenols BPS and BPF, which are analogues of BPA, have deleterious effects on reproduction even at extremely low doses. Indirect exposure via the maternal route (i.e. across the placenta and/or by breastfeeding) is underestimated, although it can be assumed to be a cause of idiopathic female infertility. Therefore, we hypothesised the deleterious effects of exposure to BPA analogues during breastfeeding on the ovarian and oocyte quality of offspring. A 15-day exposure period of pups was designed, whilst nursing dams (N ≥ 6 per experimental group) were treated via drinking water with a low (0.2 ng/g body weight/day) or moderate (20 ng/g body weight/day) dose of bisphenol, mimicking real exposure in humans. Thereafter, female pups were bred to 60 days and oocytes were collected. Immature oocytes were used in the in-vitro maturation assay; alternatively, in-vivo-matured oocytes were isolated and used for parthenogenetic activation. Both in-vitro- and in-vivo-matured oocytes were subjected to immunostaining of spindle microtubules (α-tubulin) and demethylation of histone H3 on the lysine K27 (H3K27me2) residue. Although very low doses of both BPS and BPF did not affect the quality of ovarian histology, spindle formation and epigenetic signs were affected. Notably, in-vitro-matured oocytes were significantly sensitive to both doses of BPS and BPF. Although no significant differences in spindle-chromatin quality were identified in ovulated and in-vivo-matured oocytes, developmental competence was significantly damaged. Taken together, our mouse model provides evidence that bisphenol analogues represent a risk to human reproduction, possibly leading to idiopathic infertility in women.

Mesenchymal Stromal Cell Therapy in Novel Porcine Model of Diffuse Liver Damage Induced by Repeated Biliary Obstruction.

In liver surgery, biliary obstruction can lead to secondary biliary cirrhosis, a life-threatening disease with liver transplantation as the only curative treatment option. Mesenchymal stromal cells (MSC) have been shown to improve liver function in both acute and chronic liver disease models. This study evaluated the effect of allogenic MSC transplantation in a large animal model of repeated biliary obstruction followed by partial hepatectomy. MSC transplantation supported the growth of regenerated liver tissue after 14 days (MSC group, n = 10: from 1087 ± 108 (0 h) to 1243 ± 92 mL (14 days); control group, n = 11: from 1080 ± 95 (0 h) to 1100 ± 105 mL (14 days), p = 0.016), with a lower volume fraction of hepatocytes in regenerated liver tissue compared to resected liver tissue (59.5 ± 10.2% vs. 70.2 ± 5.6%, p < 0.05). Volume fraction of connective tissue, blood vessels and bile vessels in regenerated liver tissue, serum levels of liver enzymes (AST, ALT, ALP and GGT) and liver metabolites (albumin, bilirubin, urea and creatinine), as well as plasma levels of IL-6, IL-8, TNF-α and TGF-ß, were not affected by MSC transplantation. In our novel, large animal (pig) model of repeated biliary obstruction followed by partial hepatectomy, MSC transplantation promoted growth of liver tissue without any effect on liver function. This study underscores the importance of translating results between small and large animal models as well as the careful translation of results from animal model into human medicine.

Low doses of Bisphenol S affect post-translational modifications of sperm proteins in male mice.

BACKGROUND: Bisphenol S (BPS) is increasingly used as a replacement for bisphenol A in the manufacture of products containing polycarbonates and epoxy resins. However, further studies of BPS exposure are needed for the assessment of health risks to humans. In this study we assessed the potential harmfulness of low-dose BPS on reproduction in male mice. METHODS: To simulate human exposure under experimental conditions, 8-week-old outbred ICR male mice received 8 weeks of drinking water containing a broad range of BPS doses [0.001, 1.0, or 100 µg/kg body weight (bw)/day, BPS1-3] or vehicle control. Mice were sacrificed and testicular tissue taken for histological analysis and protein identification by nano-liquid chromatography/mass spectrometry (MS) and sperm collected for immunodetection of acetylated lysine and phosphorylated tyrosine followed by protein characterisation using matrix-assisted laser desorption ionisation time-of-flight MS (MALDI-TOF MS). RESULTS: The results indicate that compared to vehicle, 100 µg/kg/day exposure (BPS3) leads to 1) significant histopathology in testicular tissue; and, 2) higher levels of the histone protein γH2AX, a reliable marker of DNA damage. There were fewer mature spermatozoa in the germ layer in the experimental group treated with 1 µg/kg bw (BPS2). Finally, western blot and MALDI-TOF MS studies showed significant alterations in the sperm acetylome and phosphorylome in mice treated with the lowest exposure (0.001 µg/kg/day; BPS1), although the dose is several times lower than what has been published so far. CONCLUSIONS: In summary, this range of qualitative and quantitative findings in young male mice raise the possibility that very low doses of BPS may impair mammalian reproduction through epigenetic modifications of sperm proteins.

Endometriosis and risk of ovarian cancer: what do we know?

PURPOSE: Despite long and intensive research, endometriosis remains one of the leading causes of morbidity among premenopausal women. The majority of endometriosis-related ovarian carcinomas occur in the presence of atypical ovarian endometriosis. Nevertheless, despite the increased incidence of ovarian cancer in patients with endometriosis, our knowledge of the risk factors and mechanisms is still incomplete. METHOD: Narrative overview, synthesizing the recent findings of literature retrieved from databases. RESULTS: Herein, we reviewed and summarized the most recent knowledge regarding endometriosis and ovarian cancer. CONCLUSION: The evidence showing that patients with endometriosis have a higher risk of developing ovarian cancer is compelling. However, the question of how much higher the absolute risk is, is not fully clear.

Sonic Hedgehog and Triiodothyronine Pathway Interact in Mouse Embryonic Neural Stem Cells.

Neural stem cells are fundamental to development of the central nervous system (CNS)-as well as its plasticity and regeneration-and represent a potential tool for neuro transplantation therapy and research. This study is focused on examination of the proliferation dynamic and fate of embryonic neural stem cells (eNSCs) under differentiating conditions. In this work, we analyzed eNSCs differentiating alone and in the presence of sonic hedgehog (SHH) or triiodothyronine (T3) which play an important role in the development of the CNS. We found that inhibition of the SHH pathway and activation of the T3 pathway increased cellular health and survival of differentiating eNSCs. In addition, T3 was able to increase the expression of the gene for the receptor smoothened (Smo), which is part of the SHH signaling cascade, while SHH increased the expression of the T3 receptor beta gene (Thrb). This might be the reason why the combination of SHH and T3 increased the expression of the thyroxine 5-deiodinase type III gene (Dio3), which inhibits T3 activity, which in turn affects cellular health and proliferation activity of eNSCs.

Long-term exposure to very low doses of bisphenol S affects female reproduction.

Bisphenols belong to the endocrine disruptors, affecting reproduction even in extremely low doses. Bisphenol S (BPS) has become widely used as a substitute for the earlier-used bisphenol A; however, its harmlessness is questionable. The aim of this study was to evaluate the effect of BPS on folliculogenesis and oocyte quality after in vivo exposure to low doses of BPS. Four-week-old ICR females (n = 16 in each experimental group) were exposed to vehicle control (VC), BPS1 (0.001 ng BPS.g/bw/day), BPS2 (0.1 ng.g/bw/day), BPS3 (10 ng.g/bw/day) and BPS4 (100 ng.g/bw/day) for 4 weeks. Ovaries were subjected to stereology and nano liquid chromatography-mass spectrometry (LC/MS). Simultaneously, metaphase II oocytes were obtained after pregnant mare serum gonadotrophin and human chorionic gonadotrophin administration, followed by immunostaining. In particular, mating and two-cell embryo flushing were performed. We observed that BPS decreases the amount of ovarian follicles and BPS2 (0.1 ng.g/bw/day) affects the volume of antral follicles. Accordingly, ovarian proteome is affected after BPS2 treatment. While BPS2 dosing results mainly in cytoskeletal damage in matured oocytes, the effects of BPS3 and BPS4 seem to be due instead to epigenetic alterations in oocytes. Arguably, these changes lead to observed affection of in vivo fertilization rate after BPS3 and BPS4 treatment. BPS significantly affects female reproduction astoundingly in extremely low doses. These findings underline the necessity to assess the risk of ongoing BPS exposure for public health.

Altered Immunity in Endometriosis: What Came First?

BACKGROUND: This study was conducted to summarize current knowledge of the changes within the immune system, from action of macrophages, lymphocytes and NK cells to biological effects of their products. Endometriosis is a complex gynecological disorder defined as a presence of endometrial tissue outside the uterus affecting over 5 million reproductive-aged women in the U.S. alone. RESULT: In recent years, the potential role of the immune system in the development of endometriosis has increasingly gained attention. Data summarized in our study showed that the most relevant immunocytes are macrophages residing inside the peritoneal cavity and the ratios of Th1 to Th2 cells. Another crucial immunological parameter is the balance in production of cytokines and chemoatractants. CONCLUSIONS: This review confirms that despite decades of intensive research, the involvement of the immune system remains elusive, as we can recognize the changes, but still do not understand if these changes represent the results of endometriosis or if they are contributing factors. Based on these findings, we also discuss new treatment possibilities.

lncRNAs in Non-Malignant Tissue Have Prognostic Value in Colorectal Cancer.

Although colorectal cancer (CRC) is the third most frequent cause of cancer related death in Europe, clinically relevant biomarkers for therapy guidance and prognosis are insufficiently reliable. Long non-coding RNAs (lncRNAs) are RNAs over 200 nucleotides long that are not translated into proteins but can influence biological processes. There is emerging evidence for their involvement in solid cancer as oncogenes, tumour suppressors or regulators of cell proliferation and metastasis development. The goal of this study was to evaluate the prognostic effect of selected lncRNAs in a retrospective study on CRC patients from the Czech Republic. We used a quantitative PCR approach to measure the expression in paired non-malignant and tumour tissue samples of CRC patients of nine lncRNAs previously shown to be involved in cancer progression-ANRIL, CCAT1, GAS5, linc-ROR, MALAT1, MIR155HG, PCAT1, SPRY4-IT1 and TUG1. Associations between expression and expression ratios and clinical characteristics and survival were assessed by using univariable Cox proportional hazards models, Kaplan-Meier estimations with the Gehan-Wilcoxon test, the Mann-Whitney U test, the Kruskal-Wallis test and Spearman's correlations. A comparison of expression in tumour tissue (TT) and non-malignant mucosa tissue (MT) showed significant upregulation of CCAT1 and linc-ROR in TT (p < 0.001 and p = 0.001, respectively) and downregulation of ANRIL, MIR155HG and MALAT1 (p = 0.001, p = 0.010, p = 0.001, respectively). Linc-ROR was significantly associated with the presence of synchronous metastases (p = 0.033). For individual tissue types, lower MIR155HG expression in TT was correlated with both shorter overall survival (p = 0.008) and shorter disease-free survival (p = 0.040). In MT, expression ratios of CCAT1/ANRIL and CCAT1/MIR155HG were associated with overall survival (p = 0.005 and p = 0.006, respectively). Our results revealed that changes in expression of lncRNAs between MT and TT hold potential to be used as prognostic biomarkers in CRC patients. Moreover, the ratios of CCAT1 to ANRIL and MIR155HG in MT also exhibit potential for prognosis assessment without tumour sampling. Our results also indicate that cancer progression is associated with detrimental system-wide changes in patient tissue, which might govern patient survival even after successful elimination of tumour or cancerous cells.

Stereological analysis of size and density of hepatocytes in the porcine liver.

The porcine liver is frequently used as a large animal model for verification of surgical techniques, as well as experimental therapies. Often, a histological evaluation is required that include measurements of the size, nuclearity or density of hepatocytes. Our aims were to assess the mean number-weighted volume of hepatocytes, the numerical density of hepatocytes, and the fraction of binuclear hepatocytes (BnHEP) in the porcine liver, and compare the distribution of these parameters among hepatic lobes and macroscopic regions of interest (ROIs) with different positions related to the liver vasculature. Using disector and nucleator as design-based stereological methods, the morphometry of hepatocytes was quantified in seven healthy piglets. The samples were obtained from all six hepatic lobes and three ROIs (peripheral, paracaval and paraportal) within each lobe. Histological sections (thickness 16 µm) of formalin-fixed paraffin-embedded material were stained with the periodic acid-Schiff reaction to indicate the cell outlines and were assessed in a series of 3-µm-thick optical sections. The mean number-weighted volume of mononuclear hepatocytes (MnHEP) in all samples was 3670 ± 805 µm3 (mean ± SD). The mean number-weighted volume of BnHEP was 7050 ± 2550 µm3 . The fraction of BnHEP was 4 ± 2%. The numerical density of all hepatocytes was 146 997 ± 15 738 cells mm-3 of liver parenchyma. The porcine hepatic lobes contained hepatocytes of a comparable size, nuclearity and density. No significant differences were identified between the lobes. The peripheral ROIs of the hepatic lobes contained the largest MnHEP with the smallest numerical density. The distribution of a larger MnHEP was correlated with a larger volume of BnHEP and a smaller numerical density of all hepatocytes. Practical recommendations for designing studies that involve stereological evaluations of the size, nuclearity and density of hepatocytes in porcine liver are provided.

Non-Invasive Approaches to Epigenetic-Based Sperm Selection.

Since sperm size and form do not necessarily provide information on internal sperm structures, novel sperm markers need to be found in order to conduct assisted reproductive therapies (ART) successfully. Currently, the priority of andrologists is not only to select those sperm able to fertilize the oocyte, but also a high quality of sperm that will guarantee a healthy embryo. Evidence of this shows us the importance of studying sperm intensively on genetic and epigenetic levels, because these could probably be the cause of a percentage of infertility diagnosed as idiopathic. Thus, more attention is being paid to posttranslational modifications as the key for better understanding of the fertilization process and its impact on embryo and offspring. Advances in the discovery of new sperm markers should go hand in hand with finding appropriate techniques for selecting the healthiest sperm, guaranteeing its non-invasiveness. To date, most sperm selection techniques can be harmful to sperm due to centrifugation or staining procedures. Some methods, such as microfluidic techniques, sperm nanopurifications, and Raman spectroscopy, have the potential to make selection gentle to sperm, tracking small abnormalities undetected by methods currently used. The fact that live cells could be analyzed without harmful effects creates the expectation of using them routinely in ART. In this review, we focus on the combination of sperm epigenetic status (modifications) as quality markers, with non-invasive sperm selection methods as novel approaches to improve ART outcomes.

Regulation of apoptotic pathways during endometriosis: from the molecular basis to the future perspectives.

PURPOSE: Endometriosis is defined as the presence of endometrial-like endometrial cells, glands and stroma outside the uterus, causing a strong inflammatory-like microenvironment in the affected tissue. This may provoke a breakdown in the peritoneal cavity homeostasis, with the consequent processes of immune alteration, documented by peripheral mononuclear cells recruitment and secretion of inflammatory cytokines in early phases and of angiogenic and fibrogenic cytokines in the late stages of the disease. Considering the pivotal role of interaction between immune and endometriotic cells, in this paper, we aim to shed light about the role of apoptosis pathways in modulating the fine-regulated peritoneal microenvironment during endometriosis. METHODS: Narrative overview, synthesizing the findings of literature retrieved from searches of computerized databases. RESULTS: In normal conditions, endometriotic cells, refluxed through the fallopian tubes into the peritoneal cavity, should be attacked and removed by phagocytes and NK cells. During endometriosis, the breakdown of peritoneal homeostasis causes the failure of scavenging mechanisms, allowing the survival of endometriotic cells. The consequent so-called "immunoescaping" of endometriotic cells could be due, at least in part, to the reduction of apoptotic-mediated pathways previously described. CONCLUSION: Considering the large amount of evidence retrieved from in vitro as well as in vivo models, the reduced apoptosis of endometriotic cells together with the increased apoptosis of peritoneal fluid mononuclear cells may address the peritoneal homeostasis to a permissive environment for the progression of the disease.

Microcirculation of the brain: morphological assessment in degenerative diseases and restoration processes.

Brain microcirculation plays an important role in the pathogenesis of various brain diseases. Several specific features of the circulation in the brain and its functions deserve special attention. The brain is extremely sensitive to hypoxia, and brain edema is more dangerous than edema in other tissues. Brain vessels are part of the blood-brain barrier, which prevents the penetration of some of the substances in the blood into the brain tissue. Herein, we review the processes of angiogenesis and the changes that occur in the brain microcirculation in the most prevalent neurodegenerative diseases. There are no uniform vascular changes in the neurodegenerative diseases. In some cases, the vascular changes are secondary consequences of the pathological process, but they could also be involved in the pathogenesis of the primary disease and contribute to the degeneration of neurons, based on their quantitative characteristics. Additionally, we described the stereological methods that are most commonly used for generating qualitative and quantitative data to assess changes in the microvascular bed of the brain.

Role of leukemia inhibitory factor in the nervous system and its pathology.

Leukemia inhibitory factor (LIF) is a multi-function cytokine that has various effects on different tissues and cell types in rodents and humans; however, its insufficiency has a relatively mild impact. This could explain why only some aspects of LIF activity are in the time-light, whereas other aspects are not well known. In this review, the LIF structure, signaling pathway, and primary roles in the development and function of an organism are reviewed, and the effects of LIF on stem cell growth and differentiation, which are important for its use in cell culturing, are described. The focus is on the roles of LIF in central nervous system development and on the modulation of its physiological functions as well as the involvement of LIF in the pathogenesis of brain diseases and injuries. Finally, LIF and its signaling pathway are discussed as potential targets of therapeutic interventions to influence both negative phenomena and regenerative processes following brain injury.

Intrauterine administration of human chorionic gonadotropin does not improve pregnancy and life birth rates independently of blastocyst quality: a randomised prospective study.

BACKGROUND: Successful embryo implantation depends on a well-timed maternal-embryonic crosstalk. Human chorionic gonadotropin (hCG) secreted by the embryo is known to play a key role in this process and to trigger a complex signal transduction cascade allowing the apposition, attachment, and invasion of the embryo into the decidualized uterus. Production of hCG was reported to be dependent on blastocyst quality and several articles suggested that intrauterine hCG injection increases pregnancy and implantation rates in IVF patients. However, no study has as yet analysed birth rates as final outcome. Our objective was to determine whether clinical outcome after blastocyst transfer can be improved by intrauterine injection of hCG and whether this is dependent on blastocyst quality. METHODS: A prospective randomised study was conducted in two settings. In cohort A, hCG application was performed two days before blastocyst transfer. In cohort B, the administration of hCG occurred just prior to embryo transfer on day 5. For both cohorts, patients were randomised to either intrauterine hCG application or to the control group that received culture medium. Clinical outcome was analysed according to blastocyst quality of transferred embryos. RESULTS: The outcome of 182 IVF-cycles (cohort A) and 1004 IVF-cycles (cohort B) was analysed. All patients received a fresh autologous blastocyst transfer on day five. Primary outcomes were pregnancy rates (PR), clinical pregnancy rates (cPR), miscarriage rates (MR), and live birth rates (LBR). No improvement of clinical outcome after intrauterine hCG administration on day 3 (cohort A) or day 5 (cohort B) was found, independently of blastocyst quality transferred. The final outcome in cohort A: LBR after transfer of top blastocysts was 50.0 % with hCG and 53.3 % in the control group. With non-top blastocysts, LBR of 17.1 % (hCG) and 18.2 % (control) were observed (n.s.). In cohort B, LBR with top blastocysts was 53.3 % (hCG) and 48.4 % (control), with non-top blastocysts it came to 28.7 % (hCG) and 35.0 % (control). The differences between the groups were statistically not significant. Furthermore, we investigated a possible benefit of hCG administration in correlation with female age. In both age groups (<38 years and ≥ 38 years) we found similar LBR after treatment with hCG vs. medium. A LBR of 47.1 % vs. 48.7 % was obtained in the younger group and 26.6 % vs. 30.8 % in the older group. CONCLUSIONS: In contrast to previous studies indicating a substantial benefit from intrauterine hCG application in cleavage stage embryo transfers, in our study we could not find any evidence for improvement of clinical outcome in blastocyst transfer cycles, neither with top nor with non-top quality morphology.

Transplantation of Embryonic Cerebellar Grafts Improves Gait Parameters in Ataxic Lurcher Mice.

Hereditary cerebellar ataxias are severe diseases for which therapy is currently not sufficiently effective. One of the possible therapeutic approaches could be neurotransplantation. Lurcher mutant mice are a natural model of olivocerebellar degeneration representing a tool to investigate its pathogenesis as well as experimental therapies for hereditary cerebellar ataxias. The effect of intracerebellar transplantation of embryonic cerebellar solid tissue or cell suspension on motor performance in adult Lurcher mutant and healthy wild-type mice was studied. Brain-derived neurotrophic factor level was measured in the graft and adult cerebellar tissue. Gait analysis and rotarod, horizontal wire, and wooden beam tests were carried out 2 or 6 months after the transplantation. Higher level of the brain-derived neurotrophic factor was found in the Lurcher cerebellum than in the embryonic and adult wild-type tissue. A mild improvement of gait parameters was found in graft-treated Lurcher mice. The effect was more marked in cell suspension grafts than in solid transplants and after the longer period than after the short one. Lurcher mice treated with cell suspension and examined 6 months later had a longer hind paw stride (4.11 vs. 3.73 mm, P < 0.05) and higher swing speed for both forepaws (52.46 vs. 32.79 cm/s, P < 0.01) and hind paws (63.46 vs. 43.67 cm/s, P < 0.001) than controls. On the other hand, classical motor tests were not capable of detecting clearly the change in the motor performance. No strong long-lasting negative effect of the transplantation was seen in wild-type mice, suggesting that the treatment has no harmful impact on the healthy cerebellum.

[Histological evaluation of biomaterials administration in vivo on the cartilage, bone and skin healing]. / Histologické hodnocení vlivu in vivo aplikace biomateriálu na hojení chrupavky, kosti a kuze.

Our aim was to show the benefits and limitations of histological assessment of healing supported by implantable biomaterials. We reviewed and showed photographs of the histological and immunohistochemical methods applicable for the assessment of desirable and undesirable effects of biomaterials on the healing of hard and soft tissues. Currently used methods for evaluating the microscopic effects of bioengineered materials on the recipient tissue are reviewed. For histopathological analysis, semiquantitative scoring systems can be used. Alternatively, the main tissue constituents may be quantified using continuous variables giving the numerical densities of cells, lengths of microvessels or connective tissue fibres, area surfaces, area and volumes fractions, or clustering and colocalization of microscopic objects. Using systematic uniform random sampling strategies at the level of tissue blocks, sections, and image fields leads to a reasonable low variability of the quantitative results.

[Arytmogenic ventricular cardiomyopathy]. / Arytmogenní ventrikulární kardiomyopatie.

Arrhythmogenic ventricular cardiomyopathy is considered to be a primary cardiomyopathy. Over the last few decades, although being a relatively rare disease with its prevalence 1:2000 - 1:5000, there were numerous studies performed with the aim to elucidate the underlaying causes, pathogenesis, diagnostical aspects and possible treatment options of the disease. Arrhythmogenic ventricular cardiomyopathy is genetically conditioned disease where proteins of the cell-cell junctions are involved. Mutations of the myocardial intercalated dics proteins, mainly desmosomal proteins (e.g.plakoglobin), are held to be responsible for electromechanical instability of the myocardium which causes regressive changes in cardiomyocytes in most cases of arrhythmogenic ventricular cardiomyopathy. Subsequent morphological changes include fibrofatty replacement and inflammation of the myocardium. The condition results in structural changes of the heart hence arrhytmias and other signs of heart disease. There are 3 variants of this cardiomyopathy: 'classical variant with predominant right ventricular involvement, biventricular and variant with left ventricular predominance. Clinical findings in patients with arrhythmogenic ventricular cardiomyopathy suggested the most appropriate means of the diagnostics and helped to create Task Force Criteria for in vivo diagnosis of the disease. The major pitfall and significance of arrhythmogenic ventricular cardiomyopathy lies in its common presentation as sudden cardiac death affecting mostly young adults.

Dynamics and necessity of SIRT1 for maternal-zygotic transition.

Dynamic changes in maternal‒zygotic transition (MZT) require complex regulation of zygote formation, maternal transcript decay, embryonic genome activation (EGA), and cell cycle progression. Although these changes are well described, some key regulatory factors are still elusive. Sirtuin-1 (SIRT1), an NAD+-dependent histone deacetylase, is a versatile driver of MZT via its epigenetic and nonepigenetic substrates. This study focused on the dynamics of SIRT1 in early embryos and its contribution to MZT. A conditional SIRT1-deficient knockout mouse model was used, accompanied by porcine and human embryos. Embryos across mammalian species showed the prominent localization of SIRT1 in the nucleus throughout early embryonic development. Accordingly, SIRT1 interacts with histone H4 on lysine K16 (H4K16) in both mouse and human blastocysts. While maternal SIRT1 is dispensable for MZT, at least one allele of embryonic Sirt1 is required for early embryonic development around the time of EGA. This role of SIRT1 is surprisingly mediated via a transcription-independent mode of action.