Surface guided radiation therapy: An international survey on current clinical practice

Introduction

Surface Guided Radiation Therapy (SGRT) is being increasingly implemented into clinical practice across a number of techniques and irradiation-sites. This technology, which is provided by different vendors, can be used with most simulation- and delivery-systems. However, limited guidelines and the complexity of clinical settings have led to diverse patterns of operation. With the aim to understand current clinical practice a survey was designed focusing on specifics of the clinical implementation and usage.

Materials and methods

A 32-question survey covered: type and number of systems, quality assurance (QA), clinical workflows, and identification of strengths/limitations. Respondents from different professional groups and countries were invited to participate. The survey was distributed internationally via ESTRO-membership, social media and vendors.

Results

Of the 278 institutions responding, 172 had at least one SGRT-system and 136 use SGRT clinically. Implementation and QA were primarily based on the vendors' recommendations and phantoms. SGRT was mainly implemented in breast RT (116/136), with strong but diverse representation of other sites. Many (58/135) reported at least partial elimination of skin-marks and a third (43/126) used open-masks. The most common imaging protocol reported included the combination of radiographic imaging with SGRT. Patient positioning (115/136), motion management (104/136) and DIBH (99/136) were the main applications.Main barriers to broader application were cost, system integration issues and lack of demonstrated clinical value. A lack of guidelines in terms of QA of the system was highlighted.

Conclusions

This overview of the SGRT status has the potential to support users, vendors and organisations in the development of practices, products and guidelines.

Effects of diffusion signal modeling and segmentation approaches on subthalamic nucleus parcellation

The subthalamic nucleus (STN) is commonly used as a surgical target for deep brain stimulation in movement disorders such as Parkinson's Disease. Tractography-derived connectivity-based parcellation (CBP) has been recently proposed as a suitable tool for non-invasive in vivo identification and pre-operative targeting of specific functional territories within the human STN. However, a well-established, accurate and reproducible protocol for STN parcellation is still lacking. The present work aims at testing the effects of different tractography-based approaches for the reconstruction of STN functional territories. We reconstructed functional territories of the STN on the high-quality dataset of 100 unrelated healthy subjects and on the test-retest dataset of the Human Connectome Project (HCP) repository. Connectivity-based parcellation was performed with a hypothesis-driven approach according to cortico-subthalamic connectivity, after dividing cortical areas into three groups: associative, limbic and sensorimotor. Four parcellation pipelines were compared, combining different signal modeling techniques (single-fiber vs multi-fiber) and different parcellation approaches (winner takes all parcellation vs fiber density thresholding). We tested these procedures on STN regions of interest obtained from three different, commonly employed, subcortical atlases. We evaluated the pipelines both in terms of between-subject similarity, assessed on the cohort of 100 unrelated healthy subjects, and of within-subject similarity, using a second cohort of 44 subjects with available test-retest data. We found that each parcellation provides converging results in terms of location of the identified parcels, but with significative variations in size and shape. All pipelines obtained very high within-subject similarity, with tensor-based approaches outperforming multi-fiber pipelines. On the other hand, higher between-subject similarity was found with multi-fiber signal modeling techniques combined with fiber density thresholding. We suggest that a fine-tuning of tractography-based parcellation may lead to higher reproducibility and aid the development of an optimized surgical targeting protocol.

The Cerebellar Dopaminergic System

In the central nervous system (CNS), dopamine (DA) is involved in motor and cognitive functions. Although the cerebellum is not been considered an elective dopaminergic region, studies attributed to it a critical role in dopamine deficit-related neurological and psychiatric disorders [e.g., Parkinson's disease (PD) and schizophrenia (SCZ)]. Data on the cerebellar dopaminergic neuronal system are still lacking. Nevertheless, biochemical studies detected in the mammalians cerebellum high dopamine levels, while chemical neuroanatomy studies revealed the presence of midbrain dopaminergic afferents to the cerebellum as well as wide distribution of the dopaminergic receptor subtypes (DRD1-DRD5). The present review summarizes the data on the cerebellar dopaminergic system including its involvement in associative and projective circuits. Furthermore, this study also briefly discusses the role of the cerebellar dopaminergic system in some neurologic and psychiatric disorders and suggests its potential involvement as a target in pharmacologic and non-pharmacologic treatments.

Structural Connectivity-Based Parcellation of the Dopaminergic Midbrain in Healthy Subjects and Schizophrenic Patients

Background and objectives: Functional deregulation of dopaminergic midbrain regions is a core feature of schizophrenia pathophysiology. Anatomical research on primates suggests that these regions may be subdivided into distinct, topographically organized functional territories according to their connectivity to the striatum. The aim of the present work was the reconstruction of dopaminergic midbrain subregions in healthy subjects and schizophrenic patients and the evaluation of their structural connectivity profiles. Materials and Methods: A hypothesis-driven connectivity-based parcellation derived from diffusion tractography was applied on 24 healthy subjects and 30 schizophrenic patients to identify distinct territories within the human dopaminergic midbrain in vivo and non-invasively. Results: We identified a tripartite subdivision of dopaminergic midbrain, including limbic, prefrontal and sensorimotor territories. No significant differences in structural features or connectivity were found between subjects and patients. Conclusions: The parcellation scheme proposed herein may help to achieve detailed characterization of structural and functional anomalies of the dopaminergic midbrain in schizophrenic patients.

Anatomical Characterization of the Human Structural Connectivity between the Pedunculopontine Nucleus and Globus Pallidus via Multi-Shell Multi-Tissue Tractography

Background and objectives: The internal (GPi) and external segments (GPe) of the globus pallidus represent key nodes in the basal ganglia system. Connections to and from pallidal segments are topographically organized, delineating limbic, associative and sensorimotor territories. The topography of pallidal afferent and efferent connections with brainstem structures has been poorly investigated. In this study we sought to characterize in-vivo connections between the globus pallidus and the pedunculopontine nucleus (PPN) via diffusion tractography. Materials and Methods: We employed structural and diffusion data of 100 subjects from the Human Connectome Project repository in order to reconstruct the connections between the PPN and the globus pallidus, employing higher order tractography techniques. We assessed streamline count of the reconstructed bundles and investigated spatial relations between pallidal voxels connected to the PPN and pallidal limbic, associative and sensorimotor functional territories. Results: We successfully reconstructed pallidotegmental tracts for the GPi and GPe in all subjects. The number of streamlines connecting the PPN with the GPi was greater than the number of those joining it with the GPe. PPN maps within pallidal segments exhibited a distinctive spatial organization, being localized in the ventromedial portion of the GPi and in the ventral-anterior portion in the GPe. Regarding their spatial relations with tractography-derived maps of pallidal functional territories, the highest value of percentage overlap was noticed between PPN maps and the associative territory. Conclusions: We successfully reconstructed the anatomical course of the pallidotegmental pathways and comprehensively characterized their topographical arrangement within both pallidal segments. PPM maps were localized in the ventromedial aspect of the GPi, while they occupied the anterior pole and the most ventral portion of the GPe. A better understanding of the spatial and topographical arrangement of the pallidotegmental pathways may have pathophysiological and therapeutic implications in movement disorders.

Microscopic reconstruction and immunohistochemical analysis of discomalleolar ligament

Discomalleolar ligament represents the vestiges of the primitive lateral pterygoid muscle which penetrates in the caudal end of Meckel's cartilage; during the development of newborn, the petrotympanic fissure close almost completely leaving inside the discomalleolar ligament. After entering in tympanic cavity, some fibers of the discomalleolar ligament insert to walls of cavity, other fibers continue with the lateral margin of the anterior ligament and insert in the neck of malleus; in contrast, other Authors demonstrated that discomalleolar ligament is an independent structure inserted in proximity of the neck of the malleus. Although the discomalleolar ligament can be considered as a structure of clinical importance, it is not described by anatomy textbooks. Moreover, it is likely that important correlations between temporomandibular diseases and otological symptoms exist. We have studied discomalleolar ligament submitting the specimens to the 3D volume rendering technique, light microscopy, reconstructing a wide light microscopic fields to analyze the real connection between retrodiscal connective tissue and middle ear, and immunofluorescence methods in order to analyze the consistence of ligament. We have shown two types of connections between TMJ and ear: first, with external acoustic meatus and, second, with middle ear through discomalleolar ligament. The different insertion represents a strong support in order to demonstrate that the TMJ disorders can determine variations of tension that are transmitted on the tympanic membrane provoking tinnitus in according to clinical features. Then, we propose that it is necessary to mention, also in anatomy textbook, the discomalleolar ligament as ligament distance of TMJ.

New insights into cortico-basal-cerebellar connectome: clinical and physiological considerations

The current model of the basal ganglia system based on the 'direct', 'indirect' and 'hyperdirect' pathways provides striking predictions about basal ganglia function that have been used to develop deep brain stimulation approaches for Parkinson's disease and dystonia. The aim of this review is to challenge this scheme in light of new tract tracing information that has recently become available from the human brain using MRI-based tractography, thus providing a novel perspective on the basal ganglia system. We also explore the implications of additional direct pathways running from cortex to basal ganglia and between basal ganglia and cerebellum in the pathophysiology of movement disorders.

The discomallear ligament: anatomical, microscopical, and radiologic analysis

BACKGROUND

Several anatomic relationships between the ear and the temporo-mandibular joint have been proposed to account for the presence of tinnitus during temporo-mandibular disorders. Among the otomandibular structures, the discomallear ligament (DML) is interposed between the malleus and the retrodiscal capsular complex. The aim of present paper was to study through dissection the frequency and morphology of DML, to characterize its type of collagen, and to evaluate the DML on routine computed tomography (CT).

METHODS AND RESULTS

The study has been conducted on five un-embalmed adult cadavers, and in all cases, the DML was present (100%). It was constituted mainly by fibers of collagen I, with abundant elastic fibers. On CT exams of 40 patients with no reported pathology of the ear, on axial images, a dense structure, going from the upper end of the petrotympanic fissure to the neck of the malleus, was present in all the cases. In 90%, it showed a triangular shape, in 5% a rectangular shape, and in 5% a curved course. The mean length of the antero-medial side was 2 ± 0.6 mm and that of the antero-lateral side was 1.63 ± 0.5, and the mean area was 1.29 ± 0.83 mm².

CONCLUSION

The DML could represent an anatomical structure that joining the temporo-mandibular joint and the malleus may play a role in the otologic symptoms during temporo-mandibular disorders.

Neuroanatomy and function of human sexual behavior: A neglected or unknown issue?

INTRODUCTION

Sexual desire, arousal, and orgasm are mediated by complex, yet still not fully understood, interactions of the somatic and autonomic nervous systems operating at the central and peripheral levels. Disruption of endocrine, neural, or vascular response, caused by aging, medical illness, neurological diseases, surgery, or drugs, can lead to sexual dysfunctions, thus significantly affecting patients' quality of life.

PURPOSE

This narrative review aims at characterizing the involvement of the central nervous system in human sexual behavior.

METHODS

A literature search was conducted using PubMed in its entirety up to June 2018, analyzing the studies dealing with the neurobiological and neurophysiological basis of human sexuality.

RESULTS

Sexual behavior is regulated by both subcortical structures, such as the hypothalamus, brainstem, and spinal cord, and several cortical brain areas acting as an orchestra to finely adjust this primitive, complex, and versatile behavior. At the central level, dopaminergic and serotonergic systems appear to play a significant role in various factors of sexual response, although adrenergic, cholinergic, and other neuropeptide transmitter systems may contribute as well.

CONCLUSIONS

Providing healthcare professionals with information concerning sexual behavior may overcome useless and sometimes dangerous barriers and improve patient management, since sexual well-being is considered one of the most important aspects of one's quality of life.

The Cortico-Basal Ganglia-Cerebellar Network: Past, Present and Future Perspectives

Much of our present understanding of the function and operation of the basal ganglia rests on models of anatomical connectivity derived from tract-tracing approaches in rodents and primates. However, the last years have been characterized by promising step forwards in the in vivo investigation and comprehension of brain connectivity in humans. The aim of this review is to revise the current knowledge on basal ganglia circuits, highlighting similarities and differences across species, in order to widen the current perspective on the intricate model of the basal ganglia system. This will allow us to explore the implications of additional direct pathways running from cortex to basal ganglia and between basal ganglia and cerebellum recently described in animals and humans.

Mapping the structural connectivity between the periaqueductal gray and the cerebellum in humans

The periaqueductal gray is a mesencephalic structure involved in modulation of responses to stressful stimuli. Structural connections between the periaqueductal gray and the cerebellum have been described in animals and in a few diffusion tensor imaging studies. Nevertheless, these periaqueductal gray–cerebellum connectivity patterns have yet to be fully investigated in humans. The objective of this study was to qualitatively and quantitatively characterize such pathways using high-resolution, multi-shell data of 100 healthy subjects from the open-access Human Connectome Project repository combined with constrained spherical deconvolution probabilistic tractography. Our analysis revealed robust connectivity density profiles between the periaqueductal gray and cerebellar nuclei, especially with the fastigial nucleus, followed by the interposed and dentate nuclei. High-connectivity densities have been observed between vermal (Vermis IX, Vermis VIIIa, Vermis VIIIb, Vermis VI, Vermis X) and hemispheric cerebellar regions (Lobule IX). Our in vivo study provides for the first time insights on the organization of periaqueductal gray–cerebellar pathways thus opening new perspectives on cognitive, visceral and motor responses to threatening stimuli in humans.

Structural connectivity-based topography of the human globus pallidus: Implications for therapeutic targeting in movement disorders

BACKGROUND

Understanding the topographical organization of the cortico-basal ganglia circuitry is of pivotal importance because of the spreading of techniques such as DBS and, more recently, MR-guided focused ultrasound for the treatment of movement disorders. A growing body of evidence has described both direct cortico- and dento-pallidal connections, although the topographical organization in vivo of these pathways in the human brain has never been reported.

OBJECTIVE

To investigate the topographical organization of cortico- and dento-pallidal pathways by means of diffusion MRI tractography and connectivity based parcellation.

METHODS

High-quality data from 100 healthy subjects from the Human Connectome Project repository were utilized. Constrained spherical deconvolution-based tractography was used to reconstruct structural cortico- and dento-pallidal connectivity. Connectivity-based parcellation was performed with a hypothesis-driven approach at three different levels: functional regions (limbic, associative, sensorimotor, and other), lobes, and gyral subareas.

RESULTS

External globus pallidus segregated into a ventral associative cluster, a dorsal sensorimotor cluster, and a caudal "other" cluster on the base of its cortical connectivity. Dento-pallidal connections clustered only in the internal globus pallidus, where also associative and sensorimotor clusters were identified. Lobar parcellation revealed the presence in the external globus pallidus of dissociable clusters for each cortical lobe (frontal, parietal, temporal, and occipital), whereas in internal globus pallidus only frontal and parietal clusters were found out.

CONCLUSION

We mapped the topographical organization of both internal and external globus pallidus according to cortical and cerebellar connections. These anatomical data could be useful in DBS, radiosurgery and MR-guided focused ultrasound targeting for treating motor and nonmotor symptoms in movement disorders. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Altered Integrins Expression of Patients Affected by Cryptorchidism

OBJECTIVES

The study aimed to investigate the expression of the integrin isoforms α7A and β1A, expressed by myogenic precursor cells, and α7B and β1D, expressed by mature muscle cells in the cremaster of patients affected by an undescended testis.

METHODS

Fifteen samples of cremaster were obtained from patients undergoing surgery for an undescended testis. Thirty control specimens of cremaster were harvested from patients with congenital hydrocele or inguinal hernia. Immunofluorescent analysis was carried out using anti-α7A, β1A, α7B, and β1D integrin antibodies. Sections were observed using confocal laser scanning microscopy.

RESULTS

As compared with controls, a significant loss of a α7B (p = 0.0355) and β1D (p = 0.0069) integrins and a higher expression of α7A (p = 0.0003) and β1A (p = 0.0150) was detected in the cremaster of patients affected by an undescended testis.

CONCLUSIONS

Our data document a critical alteration of the cytoskeleton of cremasteric smooth muscle cells in patients with an undescended testis. This might explain the altered function in smooth muscle cells in cremaster implied during testicular descent. We therefore speculate that the postnatal splicing of α7A to α7B and of β1A to β1D integrins is delayed. This could account for the common clinical scenario of spontaneous descent of the testes in the first months of life.

Human calf muscles changes after strength training as revealed by diffusion tensor imaging

BACKGROUND

Diffusion tensor imaging (DTI) is a non-invasive MR technique widely employed to study muscle anatomy. DTI parameters have been used to investigate microstructural changes dependent on demographic factors or transient condition such as exercise. The present study is aimed at investigating the diffusion parameters changes of the human calf muscles after a 3-months strength training protocol.

METHODS

Ten young men were trained for improving size and strength of the medial (GCM), lateral gastrocnemius (GCL) and soleus (SL) three times a week, with at least 24 hours between training sessions, for a period of three months. Diffusion weighted magnetic resonance images were acquired at the beginning of the training period (TPRE) and at three months (TPOST) using a 3T scanner. The fractional anisotropy (FA), mean diffusivity (MD) and tensor eigenvalues (λ1, λ2, λ3) were derived from the diffusion weighted imaging data.

RESULTS

We found a significant increase in λ1, λ2, λ3 and MD values and muscle volumes between TPRE and TPOST in all the examined muscles both for the left and right side. No significant differences were highlighted for FA.

CONCLUSIONS

DTI enables the investigation of muscle microstructure, allowing for the assessment of diffusion parameters variation of the muscle tissue in response to training thus being a useful tool to investigate physiological and pathological changes in skeletal muscle microstructure which could be employed to test the outcomes and the effectiveness of a given training protocol.

New approach in Auger elemental relative sensitive factor calculation by using TEM-EDS analysis based on bi-layers of pure elements

In fabrication of microelectronic devices two important steps are often recognized: i) all the processes performed on the wafer in order to build the active part of the devices and, ii) the assembly and packaging processes, typically performed on a chip, in order to fabricate interconnections between active part and exterior. The wafer back side is an active part of power devices and is normally coated with a stack of Ti-Ni-Au or Ti-Ni-Ag layers to ensure the best electrical contact with the frame on which the device is attached prior to the packaging. An important failure mechanism related to this particular process step is related to the diffusion of Ni to the surface of the stack that causes its oxidation on the back metal surface, inhibiting the correct connection to the metallic frame. Auger Electron Spectroscopy (AES) is a powerful analytical technique that can be used to detect this failure mechanism for its very high sensitivity in the characterization of surface layers. Unfortunately, its results are mainly qualitative. Quantitative extrapolations can be inaccurate using library Elemental Relative Sensitive Factor (ERSF) because they are mainly referred to a silicon substrate and could be not valid for a different matrix. A most accurate evaluation of the ERSF is based on the analysis, under identical experimental condition, of standard materials (with known concentration) that should be similar to the unknown sample and having the same matrix. However, the production of this kind of standard is not easy due to the mobility of Ni in Au and Ag. Another commonly used technique is the Energy Dispersive X-ray Spectrometry (EDS) which is less sensitive than the Auger and not sufficiently adequate for a quantitative analysis due to the limitation of the matrix correction methods. Recently, a new method to perform quantitative analysis by using Transmission Electron Microscopy (TEM) EDS was proposed, starting from bi-layers of pure elements. In this work we show how the use of TEM-EDS quantification of Ni in Ag could be a successful method for ERSF evaluation in order to overcome matrix effect in Auger quantification. For this purpose suitable foils of Ag/Al and Ni/Al were used. The validation of the method was performed on a sample with a tri-metal stack of Ti/Ni/Ag previously stimulated by means of a thermal budget to induce Ni migration on Ag surface. The quantitative analysis allowed us to use this characterized sample as AES standard for ERSF calculation.

Anatomical differences in the bony structure of L5 and L4: A possible classification according to the lateral tilt of the pedicles

The aim of this study is to underline the necessity of a better knowledge of pedicles anatomy in order to improve surgical treatment of spine disorders such us low back pain, spinal fractures and scholiosis. A classification of pedicles lateral tilt which could help surgeons before the application of screws during transpedicular fixation is reported. Anatomical differences in the orientiation of the pedicles of L5 and L4 have been found. For each patient that met the inclusion criteria underwent: Radiography of the lumbo-sacral region, CT examination, MRI acquisition. Patients were divided into three categories thanks to 3D direct volume rendering of CT scan. Subjects belonged to W-Type, V-Type and U-type depending on their morphometric features. The subdivision was further implemented with measurements of the distance between pedicles and adjacent nervous structures. Concerning L5, W-Type (WT) exhibited a lateral tilt of L5 larger than 36°, V-Type exhibited a lateral tilt of L5 from 30° to 36°, U-type exhibited a lateral tilt of L5 smaller than 30°. Concerning L4, WT exhibited a lateral tilt of 28.4°, VT exhibited a lateral tilt of of 25.1, UT exhibited a lateral tilt of 22.2°; we assume that the degree of lateralization of L4 depends on the one of L5. The way the screw is applied during surgical treatment is clinically relevant, thus our classification may be very useful in order to decrease surgical risk and improve conditions of patients after surgical treatment.

Diffusion tensor imaging reveals morphological alterations of the lateral pterygoid muscle in patients with mandibular asymmetry

OBJECTIVES

To evaluate non-invasively the morphological features of both lateral pterygoid muscle (LPM) and masseter muscle by using diffusion tensor Imaging on two patients affected by mandibular asymmetry.

METHODS

Two female patients with mandibular excess and asymmetry who underwent Le Fort I osteotomy and bilateral sagittal split osteotomy were recruited for this study. Morphological (T₁ weighted) and diffusion weighted images were acquired with a 3T scanner 1 week before (T0) and 1 month after the surgery (T1). Probabilistic tensor-based tractography reconstruction of bilateral masseters and LPMs was performed and mean fractional anisotropy (FA) values for both muscles were extracted.

RESULTS

Diffusion tensor imaging was able to identify the muscle geometrical morphology and diffusion microstructural changes. Both at T0 and T1, mean FA values had no significant differences between the right and left side of masseter (at T0: p = 0.91; at T1: p = 0.54) and LPM (at T0: p = 0.92; at T1: p = 0.43), respectively. Both patients reported a significant improvement in FA mean values of the left LPM (p = 0.03) between T0 and T1, whereas no diffusion parameters' changes were observed for the bilateral masseter muscles and right LPM.

CONCLUSIONS

We found that after the surgery the LPM ipsilateral to the deviation side showed a significant increase of FA compared to the baseline. Although preliminary, our findings suggest that diffusion tensor imaging may represent a promising tool to investigate non-invasively the masticatory muscles in temporomandibular joint disorders.

A Connectomic Analysis of the Human Basal Ganglia Network

The current model of basal ganglia circuits has been introduced almost two decades ago and has settled the basis for our understanding of basal ganglia physiology and movement disorders. Although many questions are yet to be answered, several efforts have been recently made to shed new light on basal ganglia function. The traditional concept of “direct” and “indirect” pathways, obtained from axonal tracing studies in non-human primates and post-mortem fiber dissection in the human brain, still retains a remarkable appeal but is somehow obsolete. Therefore, a better comprehension of human structural basal ganglia connectivity in vivo, in humans, is of uttermost importance given the involvement of these deep brain structures in many motor and non-motor functions as well as in the pathophysiology of several movement disorders. By using diffusion magnetic resonance imaging and tractography, we have recently challenged the traditional model of basal ganglia network by showing the possible existence, in the human brain, of cortico-pallidal, cortico-nigral projections, which could be mono- or polysynaptic, and an extensive subcortical network connecting the cerebellum and basal ganglia. Herein, we aimed at reconstructing the basal ganglia connectome providing a quantitative connectivity analysis of the reconstructed pathways. The present findings reinforce the idea of an intricate, not yet unraveled, network involving the cerebral cortex, basal ganglia, and cerebellum. Our findings may pave the way for a more comprehensive and holistic pathophysiological model of basal ganglia circuits.

Constrained Spherical Deconvolution Tractography Reveals Cerebello-Mammillary Connections in Humans

According to the classical view, the cerebellum has long been confined to motor control physiology; however, it has now become evident that it exerts several non-somatic features other than the coordination of movement and is engaged also in the regulation of cognition and emotion. In a previous diffusion-weighted imaging-constrained spherical deconvolution (CSD) tractography study, we demonstrated the existence of a direct cerebellum-hippocampal pathway, thus reinforcing the hypothesis of the cerebellar role in non-motor domains. However, our understanding of limbic-cerebellar interconnectivity in humans is rather sparse, primarily due to the intrinsic limitation in the acquisition of in vivo tracing. Here, we provided tractographic evidences of connectivity patterns between the cerebellum and mammillary bodies by using whole-brain CSD tractography in 13 healthy subjects. We found both ipsilateral and contralateral connections between the mammillary bodies, cerebellar cortex, and dentate nucleus, in line with previous studies performed in rodents and primates. These pathways could improve our understanding of cerebellar role in several autonomic functions, visuospatial orientation, and memory and may shed new light on neurodegenerative diseases in which clinically relevant impairments in navigational skills or memory may become manifest at early stages.

The Olfactory System Revealed: Non-Invasive Mapping by using Constrained Spherical Deconvolution Tractography in Healthy Humans

Although the olfactory sense has always been considered with less interest than the visual, auditive or somatic senses, it does plays a major role in our ordinary life, with important implication in dangerous situations or in social and emotional behaviors. Traditional Diffusion Tensor signal model and related tractography have been used in the past years to reconstruct the cranial nerves, including the olfactory nerve (ON). However, no supplementary information with regard to the pathways of the olfactory network have been provided. Here, by using the more advanced Constrained Spherical Deconvolution (CSD) diffusion model, we show for the first time in vivo and non-invasively that, in healthy humans, the olfactory system has a widely distributed anatomical network to several cortical regions as well as to many subcortical structures. Although the present study focuses on an healthy sample size, a similar approach could be applied in the near future to gain important insights with regard to the early involvement of olfaction in several neurodegenerative disorders.

Histochemical and morphological aspects of fresh frozen bone: a preliminary study

Bone graft are used in dentistry for the reconstruction of severely atrophic jaws. Fresh frozen bone has no osteogenic property but it has osteoconductive and osteoinductive properties because its matrix contains growth factors such as vascular endothelial growth factor. The purpose of the present study was to evaluate morphological and protein expression characteristics of fresh frozen bone before graft and after six months of graft in patients who needed maxillary reconstruction. After 6 month of graft we observed the presence of viable bone as evidenced by full osteocyte lacunae and by the presence of RANKR, osteocalcin positive cells and vascular endothelial growth factor. In conclusion, our findings show that the fresh frozen bone after six month of graft is for the most part viable bone, encouraging its use as an alternative to autogenous bone for reconstructing maxillary bone defects prior to implant.

Red nucleus connectivity as revealed by constrained spherical deconvolution tractography

Previous Diffusion Tensor Imaging studies have demonstrated that the human red nucleus is widely interconnected with sensory-motor and prefrontal cortices. In this study, we assessed red nucleus connectivity by using a multi-tensor model called non- negative Constrained Spherical Deconvolution (CSD), which is able to resolve more than one fiber orientation per voxel. Connections of the red nuclei of fifteen volunteers were studied at 3T using CSD axonal tracking. We found significant connectivity between RN and the following cortical and subcortical areas: cerebellar cortex, thalamus, paracentral lobule, postcentral gyrus, precentral gyrus, superior frontal gyrus and dentate nucleus. We confirmed that red nucleus is tightly linked with the cerebral cortex and has dense subcortical connections with thalamus and cerebellar cortex. These findings may be useful in a clinical context considering that RN is involved in motor control and it is known to have potential to compensate for injury of the corticospinal tract.

Extensive Direct Subcortical Cerebellum-Basal Ganglia Connections in Human Brain as Revealed by Constrained Spherical Deconvolution Tractography

The connections between the cerebellum and basal ganglia were assumed to occur at the level of neocortex. However evidences from animal data have challenged this old perspective showing extensive subcortical pathways linking the cerebellum with the basal ganglia. Here we tested the hypothesis if these connections also exist between the cerebellum and basal ganglia in the human brain by using diffusion magnetic resonance imaging and tractography. Fifteen healthy subjects were analyzed by using constrained spherical deconvolution technique obtained with a 3T magnetic resonance imaging scanner. We found extensive connections running between the subthalamic nucleus and cerebellar cortex and, as novel result, we demonstrated a direct route linking the dentate nucleus to the internal globus pallidus as well as to the substantia nigra. These findings may open a new scenario on the interpretation of basal ganglia disorders.

Sarcoglycan complex in masseter and sternocleidomastoid muscles of baboons: an immunohistochemical study

The sarcoglycan complex consists of a group of single-pass transmembrane glycoproteins that are essential to maintain the integrity of muscle membranes. Any mutation in each sarcoglycan gene causes a series of recessive autosomal dystrophin-positive muscular dystrophies. Negative fibres for sarcoglycans have never been found in healthy humans and animals. In this study, we have investigated whether the social ranking has an influence on the expression of sarcoglycans in the skeletal muscles of healthy baboons. Biopsies of masseter and sternocleidomastoid muscles were processed for confocal immunohistochemical detection of sarcoglycans. Our findings showed that baboons from different social rankings exhibited different sarcoglycan expression profiles. While in dominant baboons almost all muscles were stained for sarcoglycans, only 55% of muscle fibres showed a significant staining. This different expression pattern is likely to be due to the living conditions of these primates. Sarcoglycans which play a key role in muscle activity by controlling contractile forces may influence the phenotype of muscle fibres, thus determining an adaptation to functional conditions. We hypothesize that this intraspecies variation reflects an epigenetic modification of the muscular protein network that allows baboons to adapt progressively to a different social status.

High-Dose Robotic Stereotactic Body Radiotherapy in the Treatment of Patients With Prostate Cancer: Preliminary Results in 26 Patients

BACKGROUND

Stereotactic body radiotherapy (SBRT) can emulate high dose rate brachytherapy (HDR-BRT) dose fractionation. We report our preliminary results using SBRT in monotherapy or pre-external-beam radiotherapy (EBRT) boost in patients with localized prostate cancer (LpC). The primary end point was the evaluation of both acute and late toxicities; secondary end point was the observation of prostate-specific antigen (PSA) nadir.

PATIENTS AND METHODS

Patients with LpC having prostate volume ≤90 cm(3) were enrolled in the present study. Patients were treated with SBRT alone or in combined modality (SBRT + EBRT). SBRT was performed using a CyberKnife System (Accuray Incorporated, Sunnyvale, California) and fiducial tracking system.

RESULTS

From February 2008 to July 2013, 21 patients for monotherapy (38 Gy/4 fractions) and 5 for combined modality (9.5 Gy/2 fractions plus 46 Gy/23 fractions EBRT) were enrolled. Androgen deprivation therapy (ADT) was administered in 16 of the 26 patients. The median pretreatment PSA was 9.4 (range, 4.5-14.3) ng/mL. All patients completed the planned therapy. Acute Grade 1 toxicity was observed in 18 patients, genitourinary (GU) in 12 / 26 patients, and gastrointestinal (GI) in 6 / 26 patients. Acute Grade 2 GU toxicity was reported in 1 / 26 patients, and Grade 2 GI toxicity was observed in 2 / 26 patients. The median PSA nadir was 0.15 (range, 0.02 = 1.4) ng/mL. Late toxicities were observed in 5 / 26 patients: Grade 1 GU (3 of 26), Grade 2 GU (1 of 26), and Grade 1 GI (1 of 26). Median follow-up was 21.5 (range, 8-65) months.

CONCLUSIONS

Our preliminary results of SBRT "simulating" HDR for LpC confirm a minimal toxicity and an optimal PSA response. The PSA nadirs appear comparable with HDR-BRT.

Sarcoglycans and gaba(a) receptors in rat central nervous system: an immunohistochemical study

Sarcoglycan subcomplex is a transmembrane glycoprotein system which connects extracellular matrix to cytoskeleton. Although this complex has been found in several non-muscular tissues, no data exist about a sarcoglycan subcomplex in brain. Only the presence of ε-sarcoglycan in brain has been described in detail because its mutation determines Myoclonus Dystonia Syndrome. Also ζ-, β- and δ-sarcoglycans have been found in brain but only at mRNA level and their distribution in brain is still unknown. Here, we have searched for the expression of all sarcoglycans in specific brain regions of rat as hippocampus, cerebral and cerebellar cortex. Since a correlation between dystrophin glycoprotein complex and γ-amino butyric acid A (GABA(A)) receptor was demonstrated, we have investigated also a possible colocalization between sarcoglycans and GABA(A) receptor. Results have shown that all sarcoglycans are expressed in neurons of all observed regions; these proteins show a spot-like pattern of fluorescence and are mainly localized at soma level. Moreover, each sarcoglycan colocalizes with GABA(A) receptor. The present study shows, for the first time, the expression of all sarcoglycans in brain; moreover, the prevalent localization of sarcoglycans at post-synaptic level and the colocalization of these glycoproteins with GABA(A) receptor suggests that sarcoglycans play a key role in central nervous system, regulating post-synaptic receptors assembly.

Basal ganglia network by constrained spherical deconvolution: a possible cortico-pallidal pathway?

In the recent past, basal ganglia circuitry was simplified as represented by the direct and indirect pathways and by hyperdirect pathways. Based on data from animal studies, we hypothesized a fourth pathway, the cortico-pallidal, pathway, that complements the hyperdirect pathway to the subthalamus. Ten normal brains were analyzed by using the high angular resolution diffusion imaging-constrained spherical deconvolution (CSD)-based technique. The study was performed with a 3T magnetic resonance imaging (MRI) scanner (Achieva, Philips Healthcare, Best, Netherlands); by using a 32-channel SENSE head coil. We showed that CSD is a powerful technique that allows a fine evaluation of both the long and small tracts between cortex and basal ganglia, including direct, indirect, and hyperdirect pathways. In addition, a pathway directly connecting the cortex to the globus pallidus was seen. Our results confirm that the CSD tractography is a valuable technique allowing a reliable reconstruction of small- and long-fiber pathways in brain regions with multiple fiber orientations, such as basal ganglia. This could open a future scenario in which CSD could be used to focally target with deep brain stimulation (DBS) the small bundles within the basal ganglia loops.

Sarcoglycan complex in human normal and pathological prostatic tissue: an immunohistochemical and RT-PCR study

The sarcoglycan complex is a trans-membrane system playing a key role in mechano-signaling the connection from the cytoskeleton to the extracellular matrix. While b-, d-, and e-sarcoglycans are widely distributed, g- and a-sarcoglycans are expressed exclusively in skeletal and cardiac muscle. Insufficient data are available on the distribution of sarcoglycans in nonmuscular tissue. In the present study, we used immunohistochemical and RT-PCR techniques to study the sarcoglycans also in normal human glandular tissue, a type of tissue never studied in relation to the sarcoglycan complex, with the aim of verifying the real wider distribution of this complex. To understand the role of sarcoglycans, we tested specimens collected from patients affected by benign prostatic hyperplasia and adenocarcinoma. For the first time, our results showed that all sarcoglycans are detectable in normal samples both in epithelial and in myoepithelial cells; in pathological prostate, sarcoglycans appeared severely reduced in number or were absent. These data demonstrated that all sarcoglycans have a wider distribution suggesting a new unknown role for these proteins. The decreased number of sarcoglycans, containing cadherin domain homologs in samples of prostate affected by hyperplasia, and the absence of proteins in prostate biopsies, in cases affected by adenocarcinoma, could be responsible for the loss of adhesion between epithelial cells, which in turn facilitates the progression of benign tumors and the invasive potential of malignant tumors.

Cortical and subcortical connections of the human claustrum revealed in vivo by constrained spherical deconvolution tractography

The claustrum is a thin layer of gray matter that is at the center of an active scientific debate. Recently, Constrained Spherical Deconvolution (CSD) tractography has proved to be an extraordinary tool allowing to track white matter fibers from cortex to cortical and subcortical targets with subvoxel resolution. The aim of this study was to evaluate claustral connectivity in the human brain. Ten normal brains were analyzed by using the High Angular Resolution Diffusion Imaging CSD-based technique. Tractography revealed 4 groups of white matter fibers connecting the claustrum with the brain cortex: Anterior, posterior, superior, and lateral. The anterior and posterior cortico-claustral tracts connected the claustrum to prefrontal cortex and visual areas. The superior tract linked the claustrum with sensory-motor areas, while the lateral pathway connected the claustrum to the auditory cortex. In addition, we demonstrated a claustral medial pathway connecting the claustrum with the basal ganglia, specifically with caudate nucleus, putamen, and globus pallidus. An interesting and exciting new finding was the demonstration of a bilateral connection between claustrum and contralateral cortical areas and a well-represented interclaustral communication with interconnection bundles interspersed within the bulk of the trunk of the corpus callosum. The physiological and pathophysiological relevance of these findings are discussed.

The arterial blood supply of the temporomandibular joint: an anatomical study and clinical implications

PURPOSE

The aim of this study was to analyze three-dimensional images of the arterial supply to the temporomandibular joint.

MATERIALS AND METHODS

Ten patients (five men and five women, mean age 36 years) without signs or symptoms of temporomandibular disorders, who underwent contrast-enhanced computed tomographic (CT) scanning with intravenous contrast, were studied. The direct volume rendering technique of CT images was used, and a data set of images to visualize the vasculature of the human temporomandibular joint in three dimensions was created. After elaboration of the data through post-processing, the arterial supply of the temporomandibular joint was studied.

RESULTS

The analysis revealed the superficial temporal artery, the anterior tympanic artery, the deep temporal artery, the auricular posterior artery, the transverse facial artery, the middle meningeal artery, and the maxillary artery with their branches as the main arterial sources for the lateral and medial temporomandibular joint.

CONCLUSION

The direct volume rendering technique was found to be successful in the assessment of the arterial supply to the temporomandibular joint. The superficial temporal artery and maxillary artery ran along the lateral and medial sides of the condylar neck, suggesting that these arteries are at increased risk during soft-tissue procedures such as an elective arthroplasty of the temporomandibular joint.

Expression of muscle-specific integrins in masseter muscle fibers during malocclusion disease

Integrins are heterodimeric cell surface membrane proteins linking the extracellular matrix to actin. α7B integrin is detected in proliferating and adult myofibers, whereas α7A plays a role in regenerating muscle fibers with a minor function in mature muscle fibers. The expression levels of β1A appear to be very low, whereas β1D appears to be the predominant integrin form in mature muscle. Considering the important features of masseter muscle we have studied integrin expression in masseter muscle specimens of surgical patients with posterior right crossbite and comparing them to left side masseter muscle specimens. Our results showed that the expression of integrins was significantly lower in the crossbite side muscle. Furthermore, the most important finding is that β1A is clearly detectable in adult masseter muscle. This behavior could be due to the particular composition of masseter, since it contains hybrid fibers showing the capacity to modify the contractile properties to optimize the energy efficiency or the action of the muscle during contraction. Moreover, masseter is characterized by a high turnover of muscle fibers producing a regeneration process. This may indicate a longer time to heal, justifying the loss of β1D and the consequential increase of β1A. Thus, our data provide the first suggestion that integrins in masseter muscle play a key role regulating the functional activity of muscle and allowing the optimization of contractile forces.

Expression of sarcoglycans in the human cerebral cortex: an immunohistochemical and molecular study

The sarcoglycan (SG) complex (SGC) is a subcomplex within the dystrophin-glycoprotein complex (DGC) and is composed of several transmembrane proteins (α, β, δ, γ, ε and ζ). The DGC supplies a transmembranous connection between the subsarcolemmal cytoskeleton networks and the basal lamina in order to protect the lipid bilayer and to provide a scaffold for signaling molecules in all muscle cells. In addition to its role in muscle tissue, dystrophin and some DGC components are expressed in neurons and glia. Very little is known about the SG subunits in the central nervous system (CNS) and some data suggested the presence of ε and ζ subunits only. In fact, mutations in the ε-SG gene cause myoclonus-dystonia, indicating its importance for brain function. To determine the presence and localization of SGC in the human cerebral cortex, we performed an investigation using immunofluorescence, immunoblotting and reverse transcriptase polymerase chain reaction. The results showed that all SG subunits are expressed in the human cerebral cortex, particularly in large neurons but also in astrocytes. These data suggest that the SG subcomplex may be involved in the organization of CNS synapses.

Localization of neurotransmitters, peptides and nNOS in the pseudobranchial neurosecretory cell system and associated carotid labyrinth of the catfish, Clarias batrachus

The carotid labyrinth is an enigmatic endocrine structure of unknown chemosensory function lying in the gill region of the catfishes. The carotid body is found at the carotid bifurcation of amphibians and all mammalian vertebrates on the evolutionary tree. It is a vascular expansion comprised of a cluster of glomus cells with associated (afferent and efferent) innervations. In the catfish species studied (Clarias batrachus) a neurosecretory cell system consisting of pseudobranchial neurosecretory cells connect the carotid labyrinth or large vessels (both the efferent branchial artery and dorsal aorta), and is likely akin to the glomus cells, but comparing these structures in widely divergent vertebrate species, the conclusion is that the structural components are more elaborate than those of terrestrial vertebrates. However, these cells reveal both an endocrine phenotype (such as the association with capillaries and large vessels) and the presence of regulatory substances such as neurotransmitters and neuropeptides producing good evidence for high levels of conservation of these substances that are present in the glomus cells of mammalian vertebrates. VIP-immunopositive neuronal cell bodies are detected in the periphery of the carotid labyrinth. They are presumptive local neurons that differ from pseudobranchial neurosecretory cells, the latter failing to express VIP in their soma.

Costameric proteins: from benchside to future translational cardiovascular research

Costameres encircle the myocyte perpendicular to its long axis, and comprise two protein complexes: the dystrophin-glycoprotein complex (DGC) and the vinculin-talin-integrin system. They participate in signaling functions and protect muscle cells from damage induced by workload. The behaviour of those proteins has been a focus of study starting from skeletal and smooth muscle cells to cardiomyocytes, and still represents a topical subject for cardiovascular translational research. This review summarizes the past and present novel approaches of our and other groups of work on this subject of research.

Immunohistochemial evaluation of sarcoglycans and integrins in gingival epithelium of multiple myeloma patients with bisphosphonate-induced osteonecrosis of the jaw

Osteonecrosis of the jaw (ONJ) is an adverse outcome associated to bisphosphonate treatment. However, it is not known whether the ONJ lesion originates in the bone, or whether it may initiate in the oral mucosa. The aim of our study was to evaluate the pattern of basal lamina of oral mucosa after bisphosphonate administration and to analyze the structural damage of the mucosa in ONJ patients, and in subjects treated with bisphosphonates without osteonecrosis. By immunohistochemistry, we evaluated changes in basement membrane by expression of signalling proteins, laminin, and type IV collagen. All tested proteins were almost absent in basal lamina and mucosa of subjects treated with bisphosphonates without osteonecrosis, whereas in mucosa of patients with ONJ, they showed a clearly detectable pattern of the same proteins, specifically in basal lamina, but less in comparison to control samples. Moreover, in pathological mucosa, the clearly detectable staining pattern for VEGF indicated a massive neoangiogenesis. Bisphosphonates induce changes in expression of proteins also in oral mucosa. The increase of these proteins in basal lamina, and the neo-angiogenesis, concomitant with formation of the lesion, could indicate a compensative behaviour in the remodelling of the gingival mucosa in order to restore the epithelial architecture.

Morphometrical and morphological analysis of lateral ventricles in schizophrenia patients versus healthy controls

The goal of this report was to highlight lateral ventricle morphology and volume differences between schizophrenia patients and matched controls. Subjects identified as suitable for analysis comprised 15 schizophrenia patients and 15 healthy subjects. The method applied is three-dimensional (3D) volume rendering starting from structural magnetic resonance imaging (MRI) studies of selected ventricular regions. Differences between groups relative to the global ventricular system and its subdivisions were found. Total lateral ventricle volume, right ventricle volume and left ventricle volume were all higher in schizophrenia patients than in controls; unilateral differences between the two groups were also outlined (right ventricle volume>left ventricle volume in schizophrenia patients vs. healthy subjects). Furthermore, occipital and frontal horn enlargement was found in schizophrenia patients compared with normal controls, but the difference in the temporal horn was not statistically significant. A substantial difference was noted in lateral ventricle morphology between the two groups. Our findings were consistent with the literature and may shed light on some of the discrepancies in previous reports on differences in lateral ventricle volume enlargement.

Abnormal distribution of sarcoglycan subcomplex in colonic smooth muscle cells of aganglionic bowel

Hirschsprung's disease (HD) is a development disorder of the enteric nervous system in which the altered innervation explains the inability of the aganglionic segment to relax. Impairment of cytoskeleton in SMC of aganglionic bowel has been shown. Sarcoglycan subcomplex (SG) may support the development and maintenance of muscle cells. We examined the SG subunit expression in colonic aganglionic and ganglionic specimens obtained from patients with HD. Full-thickness bowel specimens were obtained from six patients with HD. Six normal colon specimens were used as controls. Immunofluorescent analysis and reverse transcriptase polymerase chain reaction evaluation were performed for alpha-, beta-, gamma-, delta- and epsilon-SG. In control colon, the indirect immunofluorescence showed a strong staining pattern of beta- gamma- delta- and epsilon-SG while a weak positivity of alpha-SG was recorded. In aganglionic bowel, immunofluorescence intensity values documented a significant lack of epsilon-SG while an enhanced alpha-SG, coupled to a loss of epsilon-SG, was recorded in ganglionic bowel in HD-affected patients. Our observations underscore the assumption that non-neuronal elements of the colon might play a key role in the pathogenesis of HD and loss of epsilon-SG might critically alter the cytoskeleton in the aganglionic bowel segment. Up-regulation of alpha-SG is probably an acquired phenomenon to reinforce the sarcolemma and to perform a forceful contraction in dilated ganglionic HD-affected colon, related to chronic pseudo-obstruction, contributing to the intestinal dysmotility that persists in 20% of patients after resection of the aganglionic bowel.

Sarcoglycan[s] are not muscle-specific: hypothetical roles

The sarcoglycan complex is a multimember transmembrane complex interacting with other proteins to provide a mechano-signaling connection from the cytoskeleton to the extracellular matrix in myofibers. This complex plays a key role at the membrane and is crucial in maintaining sarcolemma viability in muscle fibers. Recent observations have demonstrated that in the lung this glycoprotein is associated with both alveoli and bronchioles, and that the urogenital and digestive tracts are epsilon-sarcoglycan positive. Further addressing this issue, in this work we extend our previous studies to better verify whether the sarcoglycan complex also exists in epithelial tissue. All our observations showed staining for all sarcoglycans to be a normal pattern in all tested epithelial cells. We hypothesize a key role for sarcoglycans in bidirectional signaling between cells and extracellular matrix, and an important role in the regulation of inhibitory synapses and of blood brain barrier.

Three-dimensional volume rendering of the ankle based on magnetic resonance images enables the generation of images comparable to real anatomy

We have applied high-quality medical imaging techniques to study the structure of the human ankle. Direct volume rendering, using specific algorithms, transforms conventional two-dimensional (2D) magnetic resonance image (MRI) series into 3D volume datasets. This tool allows high-definition visualization of single or multiple structures for diagnostic, research, and teaching purposes. No other image reformatting technique so accurately highlights each anatomic relationship and preserves soft tissue definition. Here, we used this method to study the structure of the human ankle to analyze tendon-bone-muscle relationships. We compared ankle MRI and computerized tomography (CT) images from 17 healthy volunteers, aged 18-30 years (mean 23 years). An additional subject had a partial rupture of the Achilles tendon. The MRI images demonstrated superiority in overall quality of detail compared to the CT images. The MRI series accurately rendered soft tissue and bone in simultaneous image acquisition, whereas CT required several window-reformatting algorithms, with loss of image data quality. We obtained high-quality digital images of the human ankle that were sufficiently accurate for surgical and clinical intervention planning, as well as for teaching human anatomy. Our approach demonstrates that complex anatomical structures such as the ankle, which is rich in articular facets and ligaments, can be easily studied non-invasively using MRI data.

Dystrophin-glycoprotein complex and vinculin-talin-integrin system in human adult cardiac muscle

Costameres were identified, for the first time, in skeletal and cardiac muscle, as regions associated with the sarcolemma, consisting of densely clustered patches of vinculin; they have many characteristics common to the cell-extracellular matrix-type of adherens junctions. Costameres are considered 'proteic machinery' and they appear to comprise two protein complexes, the dystrophin-glycoprotein complex (DGC) and the vinculin-talin-integrin system. In comparison to skeletal muscle, few studies have focused on cardiac muscle regarding these two complexes, and study is generally relative to dystrophin or to cardiac diseases, such as cardiomyopathies. However, insufficient data are available on these proteins in healthy human cardiomyocytes. For this reason, we performed an immunohistochemical study using human cardiac muscle fibers, in order to define the real distribution and the spatial relationship between the proteins in these two complexes. Our data showed a real costameric distribution of DGC and of the vinculin-talin-integrin system; all tested proteins were present in T-tubule and in intercalated disks. Moreover, our data demonstrated that all tested proteins of DGC colocalized with each other, as all tested components of the vinculin-talin-integrin system, and that all tested proteins of DGC colocalized with all tested proteins of the vinculin-talin-integrin system. Finally, all tested proteins of the two complexes were localized in the region of the sarcolemma over the I band, in 100% of our observations. The present study, for the first time, analyzed the majority of proteins of DGC and of the vinculin-talin-integrin system in cardiac muscle fibers, and it confirmed that DGC and the vinculin-talin-integrin system have a role in the transduction of mechanical force to the extracellular matrix. Finally it attributed a key role in the regulation of action potential duration to cardiac myocytes.

Costameric proteins in human skeletal muscle during muscular inactivity

Costameres are regions that are associated with the sarcolemma of skeletal muscle fibres and comprise proteins of the dystrophin-glycoprotein complex and vinculin-talin-integrin system. Costameres play both a mechanical and a signalling role, transmitting force from the contractile apparatus to the extracellular matrix in order to stabilize skeletal muscle fibres during contraction and relaxation. Recently, it was shown that bidirectional signalling occurs between sarcoglycans and integrins, with muscle agrin potentially interacting with both types of protein to enable signal transmission. Although numerous studies have been carried out on skeletal muscle diseases, such as Duchenne muscular dystrophy, recessive autosomal muscular dystrophies and other skeletal myopathies, insufficient data exist on the relationship between costameres and the pathology of the second motor nerve and between costameric proteins and muscle agrin in other conditions in which skeletal muscle atrophy occurs. Previously, we carried out a preliminary study on skeletal muscle from patients with sensitive-motor polyneuropathy, in which we analysed the distribution of sarcoglycans, integrins and agrin by immunostaining only. In the present study, we have examined the skeletal muscle fibres of ten patients with sensitive-motor polyneuropathy. We used immunofluorescence and reverse transcriptase PCR to examine the distribution of vinculin, talin and dystrophin, in addition to that of those proteins previously studied. Our aim was to characterize in greater detail the distribution and expression of costameric proteins and muscle agrin during this disease. In addition, we used transmission electron microscopy to evaluate the structural damage of the muscle fibres. The results showed that immunostaining of alpha 7B-integrin, beta 1D-integrin and muscle agrin appeared to be severely reduced, or almost absent, in the muscle fibres of the diseased patients, whereas staining of alpha 7A-integrin appeared normal, or slightly increased, compared with that in normal skeletal muscle fibres. We also observed a lower level of alpha 7B- and beta 1D-integrin mRNA and a normal, or slightly higher than normal, level of alpha 7A-integrin mRNA in the skeletal muscle fibres of the patients with sensitive-motor polyneuropathy, compared with those in the skeletal muscle of normal patients. Additionally, transmission electron microscopy of transverse sections of skeletal muscle fibres indicated that the normal muscle fibre architecture was disrupted, with no myosin present inside the actin hexagons. Based on our results, we hypothesize that skeletal muscle inactivity, such as that found after denervation, could result in a reorganization of the costameres, with alpha 7B-integrin being replaced by alpha 7A-integrin. In this way, the viability of the skeletal muscle fibre is maintained. It will be interesting to clarify, by future experimentation, the mechanisms that lead to the down-regulation of integrins and agrin in muscular dystrophies.

An immunohistochemical, histological, and electron-microscopic study of the human periodontal ligament during orthodontic treatment

The periodontal ligament lies between the hard tissues of alveolar bone and cementum of teeth and serves to anchor the tooth to the alveolus and functions as a cushion between these hard tissues to migrate occlusal force during mastication. This tissue is always exposed to mechanical stress during mastication. When occlusal forces exceed the adaptive capacity of the periodontal ligament, the periodontal ligament tissue will be injured and then occlusal trauma will occur. The different modifications of periodontal ligament during load deformation can be monitored by analysis of the expression of different collagen types and fibronectin, with immunohistochemical techniques, and by morphological study of ligament, with light- and transmission electron-microscopic techniques. The use of continued and light orthodontic force generates a pressure of ligament with ejection of parodontal fluid externally and partial closing of vessels. On these basis we performed a study in order to evaluate periodontal ligament collagen types I and IV and the fibronectin modifications induced by application of a precalibrated orthodontic strength. We integrated these results, with light and transmission electron-microscopic observations, in order to evaluate the morphological modifications of periodontal tissue. Our observations showed that the type I collagen immunofluorescence staining is increased in the pressure side; in the tension side, it shows prior to treatment an increase, and after 72 h of treatment, a diminution of the staining pattern. Type IV collagen staining is reduced in both sides, but increased gradually after 7 days from treatment; finally, fibronectin staining pattern is gradually increased in the pressure side and reduced in the tension side. In light and transmission electron-microscopic observations it is possible to show a reduction of vessels at 72 h from treatment, and an increase of vessels after 7 days from treatment. The Malassez's epithelial residues are decreased at 72 h, while they are increased after 7 days from treatment. The modifications of immunofluorescence staining patterns of tested proteins revealed angiogenesis and reparative processes, and a thickening of fibrillar matrix as a defensive reply to mechanical stress. The modification of normal staining patterns of tested protein in our observations, could be determined by variation of scaffold geometry of periodontal ligament. The reduced movements of contraction and relaxation of periodontal ligament, due to orthodontic treatment, provoke a loss of mechanical stresses transmitted over ligament surface. Mechanical signals, therefore, could be integrated with other environmental signals and transduced into biochemical signals through force-dependent changes in scaffold geometry. Physical forces of gravity, hemodynamic stresses, and movement play a critical role in tissues, since the cells use tensegrity architecture for their structural organization.