Nuclear Volume Research Articles

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 11, November 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 11, November 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 2, February 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 2, February 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 38, Number 11, November 25, 2018

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 38, Number 11, November 25, 2018

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 6, June 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 6, June 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 3, March 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 3, March 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 4, April 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 4, April 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 5, May 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 5, May 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 10, October 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 10, October 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 1, January 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 1, January 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 9, September 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 9, September 25, 2019

Modern cervical imaging assessment. Review of literature on confocal microscopy and digital automated colposcopy

Colposcopy is today the gold standard investigation to diagnose cervical intraepithelial neoplasia (CIN) following a modified Pap smear. It is used for cervical image magnification and to guide cervical biopsy. Still, there can be other techniques that could facilitate the diagnosis of cervical neoplastic lesions and cervical cancer. This paper aims to analyze the advantages of modern cervical imaging techniques, namely confocal microscopy and digital automated colposcopy, in detecting and staging cervical neoplasia lesions. Confocal microscopy has a wide applicability as an endoscopic imaging technique and already proved useful in cases with cervical lesions. While colposcopy focuses on the macroscopic aspect of the cervical lesions, the advantage of confocal microscopy is that it provides information regarding the microscopic histological changes: architectural changes, increased volume or an increased ratio between the nuclear and cytoplasmic volumes in serial planes tangential to the epithelium, that can be reconfigured 3D. These changes are routinely diagnosed by histopathological examination of a biopsy specimen; however, the confocal microscopy has the ability to visualize these changes in vivo. This helps the diagnosis process and therapeutic decision by eliminating the time required for biopsy and histopathological examination. However, confocal microscopy is an expensive method, therefore digital colposcopy is more appropriate for the screening and diagnosis process, especially in low-income countries. In conclusion, confocal microscopy has the potential to become an important diagnostic and staging tool in cervical neoplastic lesions. The greatest benefit of this method is the ability to visualize in vivo changes that are currently detected by histopathological examination and thus to favorize a faster therapeutic management. However, because its limited accessibility, colposcopy remains the standard imaging method in the diagnosis of cervical lesions.

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 8, August 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 8, August 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 7, July 25, 2019

Chinese Journal of Nuclear Medicine and Molecular Imaging Volume 39, Number 7, July 25, 2019

Step by step procedure for stereological counts of catecholamine neurons in the mouse brainstem.

This work represents a detailed methodological description of automated stereology dedicated to all brainstem catecholamine nuclei. Each tyrosine-hydroxylase-containing nucleus was analyzed to count the following features: i) nuclear volume; ii) neuron number per nucleus; iii) neuron area per each nucleus.A number of reports described catecholamine-containing neurons within brainstem of a variety of animal species. In a recently published work, we reported a simultaneous quantitative analysis of tyrosine hydroxylase-positive neurons in the whole brainstem. Here we report the detailed step by step stereological procedure which allowed to perform a morphometric assessment of each catecholamine nucleus. This protocol provides the method chance to analyze simultaneously various morphological features in the same experimental setting to avoid variability when single nuclei are analyzed in different experiments. This improves the reliability of comparisons between brainstem catecholamine nuclei within the reticular formation to increase our insight about the key functional roles played by these cells in the mammalian brain. In fact, despite being a discrete number of neurons scattered in a small brain area, these cells provide remarkable axonal collateralization which allows the modulation of neuronal activity in the entire CNS. The step by step description of brainstem stereology provided here is reported in order to share these methods and enhance quantitative studies about these fascinating nuclei. At the same time we aim to provide a tool to be used routinely when analyzing the morphology and physiology of brainstem catecholamine cells.

Single-molecule imaging correlates decreasing nuclear volume with increasing TF-chromatin associations during zebrafish development

Zygotic genome activation (ZGA), the onset of transcription after initial quiescence, is a major developmental step in many species, which occurs after ten cell divisions in zebrafish embryos. How transcription factor (TF)-chromatin interactions evolve during early development to support ZGA is largely unknown. We establish single molecule tracking in live developing zebrafish embryos using reflected light-sheet microscopy to visualize two fluorescently labeled TF species, mEos2-TBP and mEos2-Sox19b. We further develop a data acquisition and analysis scheme to extract quantitative information on binding kinetics and bound fractions during fast cell cycles. The chromatin-bound fraction of both TFs increases during early development, as expected from a physical model of TF-chromatin interactions including a decreasing nuclear volume and increasing DNA accessibility. For Sox19b, data suggests the increase is mainly due to the shrinking nucleus. Our single molecule approach provides quantitative insight into changes of TF-chromatin associations during the developmental period embracing ZGA.

Ultrastructural Remodeling of the Neurovascular Unit in the Female Diabetic db/db Model—Part III: Oligodendrocyte and Myelin

Obesity, insulin resistance, and type 2 diabetes mellitus are associated with diabetic cognopathy. In this study, we tested the hypothesis that neurovascular unit(s) (NVU), oligodendrocytes, and myelin within cerebral cortical grey matter and deeper transitional zone regions between the cortical grey matter and white matter may be abnormal. The monogenic (Leprdb) female diabetic db/db [BKS.CgDock7m +/+ Leprdb/J] (DBC) mouse model was utilized for this ultrastructural study. Upon sacrifice (20 weeks of age), left-brain hemispheres of the DBC and age-matched non-diabetic wild type control C57BL/KsJ (CKC) mice were immediately immersion-fixed. We found prominent remodeling of oligodendrocytes with increased nuclear chromatin condensation and volume and increased numbers of active myelination sites of the cytoplasm in transition zones. Marked dysmyelination with outer myelin lamellae sheath splitting, separation, and ballooning with aberrant mitochondria in grey matter and similar myelin remodeling changes with marked disarray with additional axonal collapse in transitional zones in DBC as compared to CKC models.

LaminA/C regulates epigenetic and chromatin architecture changes upon aging of hematopoietic stem cells

BackgroundThe decline of hematopoietic stem cell (HSC) function upon aging contributes to aging-associated immune remodeling and leukemia pathogenesis. Aged HSCs show changes to their epigenome, such as alterations in DNA methylation and histone methylation and acetylation landscapes. We previously showed a correlation between high Cdc42 activity in aged HSCs and the loss of intranuclear epigenetic polarity, or epipolarity, as indicated by the specific distribution of H4K16ac.ResultsHere, we show that not all histone modifications display a polar localization and that a reduction in H4K16ac amount and loss of epipolarity are specific to aged HSCs. Increasing the levels of H4K16ac is not sufficient to restore polarity in aged HSCs and the restoration of HSC function. The changes in H4K16ac upon aging and rejuvenation of HSCs are correlated with a change in chromosome 11 architecture and alterations in nuclear volume and shape. Surprisingly, by taking advantage of knockout mouse models, we demonstrate that increased Cdc42 activity levels correlate with the repression of the nuclear envelope protein LaminA/C, which controls chromosome 11 distribution, H4K16ac polarity, and nuclear volume and shape in aged HSCs.ConclusionsCollectively, our data show that chromatin architecture changes in aged stem cells are reversible by decreasing the levels of Cdc42 activity, revealing an unanticipated way to pharmacologically target LaminA/C expression and revert alterations of the epigenetic architecture in aged HSCs.

Duration of spermatogenesis and identification of spermatogonial stem cell markers in a Neotropical catfish, Jundiá (Rhamdia quelen)

Spermatogenesis is a process driven by stem cell, where germ cell cycle is under the control of a specific genotype species. Considering that Jundiá (Rhamdia quelen) is a Neotropical catfish with great economical importance and useful experimental model, little information is available on basic aspects of its reproductive biology, especially on spermatogenesis. As a result, this study aimed to characterize the male germ cells, estimate the duration of spermatogenesis and evaluate the expression of selected stem cell genes in Jundiá testis. Similar to other fish species, our results showed a remarkable decrease of germ cell nuclear volume during Jundiá spermatogenesis, particularly from type A undifferentiated to late type B spermatogonia and from diplotene to late spermatids. Using a S-phase marker, bromodeoxyuridine (BrdU), the combined duration of meiotic and spermiogenic phases in this species was estimated in approximately 7 days. This is considered very short when compared to mammals, where spermatogenesis last from 30 to 74 days. Selected stem cell genes were partially sequenced and characterized in Jundiá testis. Expression analysis showed higher plzf and pou5f3 mRNA levels in the cell fractions enriched by type A undifferentiated spermatogonia. These results were further confirmed by in situ hybridization that showed strong signal of plzf and pou5f3 mRNA in type A undifferentiated spermatogonia. Altogether, these information will expand our knowledge of the reproductive biology of this species, contributing to improve its production and management, and also for biotechnological applications, such as germ cell transplantation.

Nuclear envelope expansion in budding yeast is independent of cell growth and does not determine nuclear volume.

Most cells exhibit a constant ratio between nuclear and cell volume. The mechanism dictating this constant ratio and the nuclear component(s) that scale with cell size are not known. To address this, we examined the consequences to the size and shape of the budding yeast nucleus when cell expansion is inhibited by down-regulating components of the secretory pathway. We find that under conditions where cell size increase is restrained, the nucleus becomes bilobed, with the bulk of the DNA in one lobe and the nucleolus in the other. The formation of bilobed nuclei is dependent on fatty acid and phospholipid synthesis, suggesting that it is associated with nuclear membrane expansion. Bilobed nuclei appeared predominantly after spindle pole body separation, suggesting that nuclear envelope expansion follows cell-cycle cues rather than cell size. Importantly, cells with bilobed nuclei had the same nuclear:cell volume ratio as cells with round nuclei. Therefore, the bilobed nucleus could be a consequence of continued NE expansion as cells traverse the cell cycle without an accompanying increase in nuclear volume due to the inhibition of cell growth. Our data suggest that nuclear volume is not determined by nuclear envelope availability but by one or more nucleoplasmic factors.

Mercury Stable Isotope Fractionation during Abiotic Dark Oxidation in the Presence of Thiols and Natural Organic Matter.

Mercury (Hg) stable isotope fractionation has been widely used to trace Hg sources and transformations in the environment, although many important fractionation processes remain unknown. Here, we describe Hg isotope fractionation during the abiotic dark oxidation of dissolved elemental Hg(0) in the presence of thiol compounds and natural humic acid. We observe equilibrium mass-dependent fractionation (MDF) with enrichment of heavier isotopes in the oxidized Hg(II) and a small negative mass-independent fractionation (MIF) owing to nuclear volume effects. The measured enrichment factors for MDF and MIF (ε202Hg and E199Hg) ranged from 1.10‰ to 1.56‰ and from -0.16‰ to -0.18‰, respectively, and agreed well with theoretically predicted values for equilibrium fractionation between Hg(0) and thiol-bound Hg(II). We suggest that the observed equilibrium fractionation was likely controlled by isotope exchange between Hg(0) and Hg(II) following the production of the Hg(II)-thiol complex. However, significantly attenuated isotope fractionation was observed during the initial stage of Hg(0) oxidation by humic acid and attributed to the kinetic isotope effect (KIE). This research provides additional experimental constraints on interpreting Hg isotope signatures with important implications for the use of Hg isotope fractionation as a tracer of the Hg biogeochemical cycle.