Entire Tissue Volume Research Articles

Health Effects of Ionizing Radiation on the Human Body.

Radioactivity is a process in which the nuclei of unstable atoms spontaneously decay, producing other nuclei and releasing energy in the form of ionizing radiation in the form of alpha (α) and beta (β) particles as well as the emission of gamma (γ) electromagnetic waves. People may be exposed to radiation in various forms, as casualties of nuclear accidents, workers in power plants, or while working and using different radiation sources in medicine and health care. Acute radiation syndrome (ARS) occurs in subjects exposed to a very high dose of radiation in a very short period of time. Each form of radiation has a unique pathophysiological effect. Unfortunately, higher organisms-human beings-in the course of evolution have not acquired receptors for the direct "capture" of radiation energy, which is transferred at the level of DNA, cells, tissues, and organs. Radiation in biological systems depends on the amount of absorbed energy and its spatial distribution, particularly depending on the linear energy transfer (LET). Photon radiation with low LET leads to homogeneous energy deposition in the entire tissue volume. On the other hand, radiation with a high LET produces a fast Bragg peak, which generates a low input dose, whereby the penetration depth into the tissue increases with the radiation energy. The consequences are mutations, apoptosis, the development of cancer, and cell death. The most sensitive cells are those that divide intensively-bone marrow cells, digestive tract cells, reproductive cells, and skin cells. The health care system and the public should raise awareness of the consequences of ionizing radiation. Therefore, our aim is to identify the consequences of ARS taking into account radiation damage to the respiratory system, nervous system, hematopoietic system, gastrointestinal tract, and skin.

Frequency-domain passive cavitation imaging

Apfel’s three golden rules (know thy sound field, know thy liquid, and know when something happens) should be considered when monitoring acoustic cavitation-based ultrasound therapies. The third rule is often followed using passive cavitation detection with a single-element transducer. However, therapy guidance demands monitoring cavitation activity in the entire tissue volume of interest. Using array-based passive cavitation detection with appropriate beamforming, maps of cavitation activity can be superimposed on pulse-echo, grayscale images of tissue anatomy. In this talk, we will discuss one approach for generating cavitation activity maps, frequency-domain passive cavitation imaging (FD-PCI). FD-PCI implements a delay, sum, and integrate algorithm, which will be described conceptually and mathematically. The advantages and limitations of the algorithm will be discussed in the context of examples. Advantages of FD-PCI include the innate frequency selectivity of the algorithm, the ability to use parallel computing for increased processing speed, the independence of the image resolution from the therapy insonation pulse shape, and the ability to quantify the acoustic power of emissions detected by the array. Challenges of the algorithm will also be discussed, including poor axial resolution and limitations of estimating the emitted acoustic power.

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning.

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans.

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans.

Philately in molecular biology research of human gliomas in the era of omics

WHO grade II–IV gliomas are profiled for a number of genes such as MGMT, TP53 and IDH1/2 or their proteins or other proteins such as KI-67 [1]. The combined profile of an individual glioma is of prognostic value and guides therapeutic choices in neuro-oncology group meetings—which is totally amazing as the present profiling only scratches the surface of the enormous bioinformatic data within the entire tissue volume of the profiled glioma. It is easier to believe that a gene here or a protein there does not mean much. Philately of studying a single gene or protein expression in gliomas is mostly (1) outdated in the era of genomics and any omics and (2) fails to suggest new targets for synthetic antitumor drugs, which are thousands in store but will never be tested in gliomas with the present validation method of randomized multicenter trials. Or the reader should at least be provided with analyses and figures of the signaling pathways involved. By DNA and RNA sequencing, we have just surveyed the ground floor of the department store of genomic information in each of our cells—and we know little of the information available in the upper floors (methylome, acetylome, histonome, etc.) up to the chromosomes (‘chromosome’?). No one with a recent medical education can think that our body and brain are made from some 20,000 genes in our cells, making only some 1 % of the whole genome. How is it possible that a fly with a pitiful 100.000 to 250.00 neurons can fly so precisely and quickly? This is because those neurons make a formidable aerobatic network of some 10 synapses. Our own brain—the most complex machine in the known universe—contains some 10 synapses, an unimaginable network exceeding the combined capacity of all the computers in the world! This leads to three obvious questions:

Experimental justification for using 3D conductivity reconstructions in electrical impedance tomography

Conductivity imaging of the breast using electrical impedance tomography (EIT) is a three-dimensional (3D) problem since the induced currents are free to travel through the entire tissue volume. It is therefore necessary to determine the effect this 3D current flow has on the image reconstruction problem and to ascertain how much benefit is gained by using a more appropriate 3D model to estimate the conductivity distribution. In addition, it is important to consider how much is gained if measurements are collected from multiple circular arrays of electrodes positioned around the breast as opposed to just a single plane of electrodes. We used a 64 electrode EIT system to collect data from a series of high contrast saline phantoms to determine the benefits gained by using a 3D model and the incorporation of out-of-plane measurements. We found that it is preferable to use a 3D mesh even when looking only at a single plane through the object of interest and that this 3D mesh should extend in the axial direction at least one radius away from the plane of interest. Further, out-of-plane measurements enhance axial information and improve the quantification of reconstructed inclusions by a factor of 2.2 in the particular case presented here. These findings should ultimately be incorporated to clinical imaging with EIT when circular electrode arrays are employed.

Imaging tumor angiogenesis by use of combined near-infrared diffusive light and ultrasound.

A novel two-step reconstruction scheme using a combined near-infrared and ultrasound technique and its utility in imaging distributions of optical absorption and hemoglobin concentration of breast lesions are demonstrated. In the first-step image reconstruction, the entire tissue volume is segmented based on initial coregistered ultrasound measurements into lesion and background regions. Reconstruction is performed by use of a finer grid for lesion region and a coarse grid for the background tissue. As a result, the total number of voxels with unknown absorption can be maintained on the same order of total measurements, and the matrix with unknown total absorption distribution is appropriately scaled for inversion. In the second step, image reconstruction is refined by optimization of lesion parameters measured from ultrasound images. It is shown that detailed distributions of wavelength-dependent absorption and hemoglobin concentration of breast carcinoma can be obtained with the new reconstruction scheme.

Measurement of Cryoprotective Solvent Penetration into Intact Organ Tissues Using High-Field NMR Microimaging

Existing methods are not able to monitor accurately the penetration of cryoprotective solvents (CPS) into intact tissues. In this study, NMR imaging is shown to be a noninvasive nondestructive way to measure penetration rates and effective diffusion coefficients of Me2SO into samples of rat kidney and rat liver tissues. This new method is unique in that the measurements obtained are not averaged over the entire tissue volume but may be made at any site in the tissue. Measurements of penetration rates yield values which are similar to literature values, and the effective diffusion coefficients fall within the expected range. The images also suggest an explanation of why CPSs fail to completely protect organs from freezing damage.

Norflurazon Absorption by Excised Velvetleaf (Abutilon theophrasti) Roots

The absorption of norflurazon [4-chloro-5-(methylamino)-2-(3-(trifluromethyl)phenyl)-3(2H)-pyridazinone] by 1-cm segments cut from the apical 5-cm roots of velvetleaf (Abutilon theophrastiMedik. # ABUTH) was studied. Norflurazon absorption was rapid in the first 10 min but there was very little increase thereafter up to 120 min. Norflurazon also penetrated the entire tissue volume within 30 min after the root segments were placed in absorption solution. Norflurazon did not accumulate to concentrations above the external solution over 120 min, and 90% of the absorbed herbicide diffused freely out of the tissue within 10 min. The metabolic inhibitor KCN did not affect norflurazon uptake, whereas pretreatment of root tissue with DNP increased absorption. Anoxia increased absorption by 60 and 120% above aerated treatment at 10 min and 2 h, respectively. These experiments suggest that norflurazon, which is considered to move primarily in the apoplast, moved into both the apoplast and symplast of velvetleaf root cells by simple diffusion.

Entry of pesticides into the plant symplast as measured by their loss from an ambient solution

AbstractA method was developed to determine the extent of penetration of substances into the plant symplast. The known apoplastic dye trisodium 3‐hydroxy‐5,8,10‐pyrenetri‐sulphonate (PTS) and various systemic pesticides were studied using potato tuber tissue. The dye penetrated only 5% of the volume of living tissue while those pesticides which display an apoplastic pattern of transport in plants penetrated the entire tissue volume. The pesticides diffused freely out of the tissue when it was transferred to fresh medium. It is proposed that the term euapoplastic be used to describe chemicals that behave like the dye, and that the term pseudoapoplastic be used to describe chemicals that behave like atrazine, carbendazim, carboxin and diuron. 2,4‐D, which displays a symplastic transport pattern in the plant, was concentrated by the tissue and did not diffuse out freely. It appears that the property which allows a pesticide to be transported in the symplast is not its ability to penetrate the plasmalemma but rather its ability to be retained by the symplast after entry.