Brain sizes, surfaces, and neuronal sizes of the cortex cerebri: a stereological investigation of man and his variability and a comparison with some mammals (primates, whales, marsupials, insectivores, and one elephant)

This study deals with the stereological estimation of macroscopic sizes of brain and cortex, i.e., volume, surface, and folding, and of microscopic neuronal sizes, i.e., density, mean size, size distribution, and number of neurons. The results show that the degree of variability in man amounts to about 15%. A decrease in volume of the different gray structures can be observed in man after the age of 65 years. The surface, folding index, and length of convolution do not alter with aging. The comparison with mammals of various sizes allows the conclusion that there is a high correlation to brain size for nearly all macroscopic values. Man and elephant, however, have a cortical surface which is, in comparison with whales, relatively small. In contrast, whales have very small cortices compared with man. At the cytoarchitectonic level, the neuronal density has a correlation to brain size. Contrary to other mammals, the primates and man have a high fraction of small granular neurons, especially in layer 4. The assumption that the number of cortical neurons beneath a given surface area of cortex is the same in all mammals cannot be verified, especially in those with large brains. The allometric connection between brain size and parameters is not valid for all measurements (e.g., thickness of cortex, mean size of neurons, perikaryal size distribution, and glial density). Yet some other measurements are well correlated.     

Novel efficient methods for measuring mesophyll anatomical characteristics from fresh thick sections using stereology and confocal microscopy: application on acid rain-treated Norway spruce needles

Recent design-based stereological methods that can be applied to thick sections cut in an arbitrary direction are presented and their implementation for measuring mesophyll anatomical characteristics is introduced. These methods use software-randomized virtual 3D probes, such as disector and fakir test probes, in stacks of optical sections acquired using confocal microscopy. They enable unbiased estimations of the mean mesophyll cell volume, mesophyll cell number in a needle, and for the first time an internal surface area of needles or other narrow leaves directly from the fresh tissue cross-sections cut using a hand microtome. Therefore, reliable results can be obtained much faster than when using a standard microtechnical preparation. The proposed methods were tested on Norway spruce needles affected for 1 year by acid rain treatment. The effect of acid rain resulted in changes of mesophyll parameters: the ratio of intercellular spaces per mesophyll cell volume increased, while needle internal surface area, total number of mesophyll cells, and number of mesophyll cells per unit volume of a needle decreased in the treated needles.     

Visualisation and stereological assessment of blood and lymphatic vessels

The physiological processes involved in tissue development and regeneration also include the parallel formation of blood and lymphatic vessel circulations which involves their growth, maturation and remodelling. Both vascular systems are also frequently involved in the development and progression of pathological conditions in tissues and organs. The blood vascular system circulates oxygenated blood and nutrients at appropriate physiological levels for tissue survival, and efficiently removes all waste products including carbon dioxide. This continuous network consists of the heart, aorta, arteries, arterioles, capillaries, post-capillary venules, venules, veins and vena cava. This system exists in an interstitial environment together with the lymphatic vascular system, including lymph nodes, which aids maintenance of body fluid balance and immune surveillance. To understand the process of vascular development, vascular network stability, remodelling and/or regression in any research model under any experimental conditions, it is necessary to clearly and unequivocally identify and quantify all elements of the vascular network. By utilising stereological methods in combination with cellular markers for different vascular cell components, it is possible to estimate parameters such as surface density and surface area of blood vessels, length density and length of blood vessels as well as absolute vascular volume. This review examines the current strategies used to visualise blood vessels and lymphatic vessels in two- and three-dimensions and the basic principles of vascular stereology used to quantify vascular network parameters.     

Structural rearrangements of the cerebral cortex in children and adolescents

The cortical formations of the brain involved in visual functions (the occipital and temporo-parieto- occipital areas, the oculomotor area of the prefrontal cortex), as well as the motor cortex in the representation zone of the arm and the medial region of the frontal cortex adjacent to the limbic lobe, were studied in post-mortem material. The thickness of the cortex and cortical layer III, the sizes of pyramidal neurons, the specific volumes of neurons and intracortical vessels were studied in subjects of both sexes, from birth to the age of 20 years, at yearly intervals (103 observations) using histological techniques, computer morphometric and stereological analysis. The thickness of the cortex of the cerebral hemispheres was observed to intensively increase from birth to the age of 3 years in the occipital, temporo-parieto-occipital and prefrontal cortical areas involved in visual recognition processes. The increase in thickness of the cerebral cortex continues until the age of 6 in the occipital cortex and in the oculomotor area, until the age of 7 years in the temporo-parietooccipital area and the medial prefrontal area, and until the age of 8–9 years in the motor cortex. The sizes of pyramidal neurons increase until the age of 6 years in the motor cortex, until the age of 8 years on the medial surface of the frontal lobe, and until the age of 9–10 years in the temporo-parieto-occipital area and in the dorsolateral area of the prefrontal cortex. The specific volume of neurons and blood vessels in the cortex of the cerebral hemispheres decreases and the volume of intracortical fibers increases throughout the ascending ontogeny, which is manifested most intensively in the prefrontal cortex.     

An alternative method of anthropometry of anterior cruciate ligament through 3-D digital image reconstruction

Accurate and flexible measurements of length, area, and volume are important in evaluation of the mechanical properties of soft tissue. Although a number of contact-based and non-contact techniques have been reported in the literature, due to a variety of reasons such as cost, complexity, and low accuracy, the research community has not adopted a standardized technique. In this paper, an alternative method of measuring the geometric parameters of cadaver anterior cruciate ligament (ACL) is presented. In this method, a 3-D scan of the ACL is constructed using a simple, commercially available, scanning system. The 3-D scan is then analyzed using the 3-D Doctor Software to extract important information regarding the length, cross-sectional area, and volume of the ACL. The accuracy and repeatability of measurements obtained by this method are acceptable and comparable to existing non-contact methods. The limitation of the method is that surface concavities cannot be detected. However, the non-contact optical method, described here, has inherent advantages over the existing methods: (1) it is inexpensive; (2) it allows the determination of area at any distance along the length of the tissue of interest; (3) all relevant information including minimum area is extracted from one single application of the method; (4) the volume can be calculated with a simple additional step of length measurement although, for accurate results, condylar blockage must be minimized by coring the ACL out. The entire process of scanning takes less than 30 min. This technique has the potential to become a standard method in anthropometry of soft tissue.     

Molecular aspects of individual radiosensitivity

Radiation therapy is a clinical treatment modality where ionizing radiation is used to treat patients with malignant neoplasms. The goal is to deliver a measured dose of radiation to a defined volume with minimal damage to surrounding normal tissue, resulting in eradication of the tumor. Radiotherapy is generally given in divided doses or fractionated. Molecular biology methods have enhanced our ability to investigate the response of cells to ionizing radiation. These methods can be applied to tissue-culture systems or to biopsies from patients both to develop a quick and easy way to predict the radiosensitivity of a patient and to understand how cells respond to stress produced by ionizing radiation. In this review we will mainly explain two major mechanisms involved in human individual radiosensitivity: the DNA-damage repair defect mechanism and the DNA-repair signaling via cell cycle checkpoint defect.     

Limbic frontal cortex in hominoids: A comparative study of area 13

The limbic frontal cortex forms part of the neural substrate responsible for emotional reactions to social stimuli. Area 13 is one of the cortical areas long known to be part of the posterior orbitofrontal cortex in several monkey species, such as the macaque. Its presence nevertheless in the human brain has been unclear, and the cortex of the frontal lobe of the great and lesser apes remains largely unknown. In this study area 13 was identified in human, chimpanzee, bonobo, gorilla, orangutan, and gibbon brains, and cortical maps were generated on the basis of its cytoarchitecture. Imaging techniques were used to characterize and quantify the microstructural organization of the area, and stereological tools were applied for estimates of the volume of area 13 in all species. Area 13 is conservative in its structure, and features such as size of cortical layers, density of neurons, and space available for connections are similar across hominoids with only subtle differences present. In contrast to the homogeneity found in its organization, variation is present in the relative size of this cortical area (as a percentage of total brain volume). The human and the bonobo include a complex orbitofrontal cortex and a relatively smaller area 13. On the contrary the orangutan stands out by having a shorter orbitofrontal region and a more expanded area 13. Differences in the organization and size of individual cortical areas involved in emotional reactions and social behavior can be related to behavioral specializations of each hominoid and to the evolution of emotions in hominids. Am J Phys Anthropol 106:129–155, 1998. © 1998 Wiley-Liss, Inc.     

Advances of radiation sterilisation in tissue banking

Under the auspices of the IAEA tissue banking programme on “Radiation Sterilisation of Tissue Graft” conducted from 1985 to 2004, many scientists and surgeons were involved in various regional research and development (R&D) projects mainly in dealing with radiation dose selection, radiation effects on human tissues and quality system in radiation sterilisation. New findings on radiation effects, tissue processing and preservation were shared during the regional and interregional meetings and workshops. Many tissue banks started to use radiation (25 kGy) to sterilize tissue grafts for tissue safety and efficacy and still continue to use it. The IAEA Code of Practice for Radiation Sterilization of Tissues Allografts developed in 2007 offered simpler methods to conduct radiation dose setting and dose validation experiments for tissue grafts. Advances in dose selection and dose mapping are continued under the quality management system when banks need to be certified to continue their operation. The combination of good tissue processing and preservation as well as good radiation practice will ensure the tissue products are properly sterilised thus safe and of high quality. Experience in meeting challenges in using radiation sterilisation and achievements reported by the tissue bankers are shared here.     

High-Precision Radiosurgical Dose Delivery by Interlaced Microbeam Arrays of High-Flux Low-Energy Synchrotron X-Rays

Microbeam Radiation Therapy (MRT) is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy). Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 µm wide, spaced 200 µm on-center, 50 to 350 keV in energy range), targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm³ in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing surrounding tissues. The use of synchrotron-generated X-rays enables delivery of high doses for destruction of small focal regions in human brains, with sharper dose fall-offs than those described in any other conventional radiation therapy.     

Changes in vascular permeability following thorax irradiation in the rat

A double isotope technique was used to measure changes in the vascular permeability surface area product (PS) for albumin after irradiation. PS was measured in several tissues of the rat during the first 38 days following 11, 13.5, 18, or 25 Gy whole thorax irradiation. After 18 and 25 Gy most irradiated and nonirradiated (shielded) tissues showed elevated permeability at 1 day after radiation, which declined to control levels by Day 4. All irradiated tissues showed a second wave of increased permeability between 14 and 38 days after radiation that varied in onset and extent depending upon tissue and dose. Lung and heart showed a direct response to dose between 11 and 18 Gy during this period. Peak lung values averaged three times control values at 19 days after 18 Gy. Peak heart values averaged twice control values at the same time and dose. The double isotope technique has proven to be a reliable means of quantitatively determining vascular permeability response to radiation over time.     

Radiobiology of the acute radiation syndrome

Acute radiation syndrome or acute radiation sickness is classically subdivided into three subsyndromes: the hematopoietic, gastrointestinal and neurovascular syndrome but many other tissues can be damaged. The time course and severity of clinical signs and symptoms are a function of the overall body volume irradiated, the inhomogeneity of dose exposure, the particle type, the absorbed dose and the dose rate. Classical pathophysiology explain the failure of each of these organs and the timing of appearance of their signs and symptoms due to radiation-induced cytocidal effects of a great number of parenchymal cells of hierarchically organized tissues. Contemporaneously, many other radiation-induced effects has been described and all of them may lead to tissue injury with their corresponding signs and symptoms that can be expressed after short or long period of time. Radiation-induced multi-organ involvement is thought to be due to radiation-induced systemic inflammatory response mediated by released pro-inflammatory cytokines.     

Glucose Transporter of the Blood-Brain Barrier and Brain in Chronic Hyperglycemia

The effect of chronic hyperglycemia on the glucose transporter moiety of the blood-brain barrier and cerebral cortex was studied in rats 3 weeks after the administration of a single intravenous dose of streptozotocin (60 mg/kg), using specific [3H]cytochalasin B binding methods. Streptozotocin-treated rats developed hyperglycemia, as well as polydipsia and polyuria, and failed to gain weight. The density of D-glucose-displaceable cytochalasin B binding sites in the brain microvessels of streptozotocin-treated hyperglycemic rats was increased by about 30% compared with those of control rats, without change in the affinity of binding. Chronic hyperglycemia had no effect on the density or affinity of specific binding of cytochalasin B to cerebral cortical membranes. These findings do not support the hypothesis that glucose transporters in brain microvessels comprising the blood-brain barrier are "down-regulated" in chronic hyperglycemia.     

Alterations in Cortical Morphology after Neonatal Stroke: Compensation in the Contralesional Hemisphere?

Although neonatal arterial ischemic stroke is now well‐studied, its complex consequences on long‐term cortical brain development has not yet been solved. In order to understand the brain development after focal early brain lesion, brain morphometry needs to be evaluated using structural parameters. In this work, our aim was to study and analyze the changes in morphometry of ipsi‐ and contralesional hemispheres in seven‐year‐old children following neonatal stroke. Therefore, we used surface‐based morphometry in order to examine the cortical thickness, surface area, cortical volume, and local gyrification index in two groups of children that suffered from neonatal stroke in the left (n = 19) and right hemispheres (n = 15) and a group of healthy controls (n = 30). Reduced cortical thickness, surface area, and cortical volumes were observed in the ipsilesional hemispheres for both groups in comparison with controls. For the group with left‐sided lesions, higher gyrification of the contralesional hemisphere was observed primarily in the occipital region along with higher surface area and cortical volume. As for the group with right‐sided lesions, higher gyrification was detected in two separate clusters also in the occipital lobe of the contralesional hemisphere, without a significant change in cortical thickness, surface area, or cortical volume. This is the first time that alterations of structural parameters are detected in the “healthy” hemisphere after unilateral neonatal stroke indicative of a compensatory phenomenon. Moreover, findings presented in this work suggest that lesion lateralization might have an influence on brain development and maturation.     

Retrospective comparison of rectal toxicity between carbon-ion radiotherapy and intensity-modulated radiation therapy based on treatment plan,normal tissue complication probability model,and clinical outcomes in prostate cancer

This retrospective study assessed the treatment planning data and clinical outcomes for 152 prostate cancer patients: 76 consecutive patients treated by carbon-ion radiation therapy and 76 consequtive patients treated by moderate hypo-fractionated intensity-modulated photon radiation therapy. These two modalities were compared using linear quadratic model equivalent doses in 2 Gy per fraction for rectal or rectal wall dose–volume histogram, 3.6 Gy per fraction-converted rectal dose–volume histogram, normal tissue complication probability model, and actual clinical outcomes. Carbon-ion radiation therapy was predicted to have a lower probability of rectal adverse events than intensity-modulated photon radiation therapy based on dose–volume histograms and normal tissue complication probability model. There was no difference in the clinical outcome of rectal adverse events between the two modalities compared in this study.     

Comparison of methods for staining microvessels in bone

Detection of microvessels is critical for studying bone tissue. We developed an intravascular ink-based method coupled with Van Gieson (VG) staining and compared it with other commonly used methods for capillary visualization. The ink perfusate was formulated as 10% ink, 10% formaldehyde and 20% mannitol. The ink solution was perfused into a healthy goat and the tibia was subjected to decalcification, dehydration, paraffin embedding, de-waxing and staining to observe microvessels. Angiogenesis was assessed by vascular area image analysis and the hematoxylin and eosin (HE), Masson, and VG staining techniques were compared to determine the reliability of these methods for counting microvessels. We found that HE, Masson, and VG staining produced poor contrast between the microvessels and surrounding tissues. By contrast, ink coupled with VG staining permitted clear discrimination between the microvessels and surrounding tissues. Our results indicate that ink-VG staining could be more useful than other methods for detecting tissue microvessels.     

小鼠急性低氧暴露时脑微循环障碍的研究

本研究旨在通过急性减压缺氧状态下脑微循环改变的观察进一步探讨急性高原病的发生机理。实验采用鼠尾静脉注射吖啶橙荧光素作标记,落射荧光显微镜观察分析。结果表明,急性低氧状态下脑血管普遍扩张,但脑表面微血管的扩张大于脑深部微血管的扩张,微动脉的扩张大于微静脉的扩张;脑表面及深部的毛细血管开放数目增多、密度增加、间距缩小;脑血流随缺氧加重而变慢并有淤积;微血管周围有渗出及出血;神经细胞肿胀,胞浆内有空泡水肿。提示急性高原缺氧状态下脑微循环有明显障碍。     

Amyloid Beta1-40-Induced Astrogliosis and the Effect of Genistein Treatment in Rat: A Three-Dimensional Confocal Morphometric and Proteomic Study

Astrocytes are highly involved in regulation and homeostasis of the extracellular environment in the healthy brain. In pathological conditions, these cells play a major role in the inflammatory response seen in CNS tissues, which is called reactive astrogliosis and includes hypertrophy and proliferation of astrocytes. Here, we performed 3D confocal microscopy to evaluate the morphological response of reactive astrocytes positive for glial fibrillary acidic protein (GFAP) in rats, to the presence of Aβ_1–40 in the rat brain before and after treatment with genistein. In 50 astrocytes per animal, we measured the volume and surface area for the nucleus, cell body, the entire cell, the tissue covered by single astrocytes and quantified the number and length of branches, the density of the astrocytes and the intensity of GFAP immunoreactivity. Injecting Aβ_1–40 into the brain of rats caused astrogliosis indicated by increased values for all measured parameters. Mass spectrometric analysis of hippocampal tissue in Aβ_1–40-injected brain showed decreased amounts of tubulins, enolases and myelin basic protein, and increased amounts of dihydropyrimidinase-related protein 2. In Aβ_1–40-injected rats pretreated with genistein, GFAP intensity was decreased to the sham-operated group level, and Aβ_1–40-induced astrogliosis was significantly ameliorated.     

Stereological Implications of the Geometry of Cones

Given a cone around a curve β in IR³ it is shown that there is no relation between the curvature of β and the volume of the cone but, in contrast to the volume, the surface area of the cone depends, albeit rather weakly, on the curvature of β. The geometric meaning of the stereological formulae when applied to cones is considered and it is noted that stereological methods to estimate the surface area of a cone need to be extremely precise to provide information concerning curvature or tortuosity.