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Journal of Neurological Surgery. Part... Apr 2016The perineural space is a compartment located between the nerve axons, supporting cells and tissues, and the epineural fibrous sheath. Tumor cells invade this space in... (Review)
Review
The perineural space is a compartment located between the nerve axons, supporting cells and tissues, and the epineural fibrous sheath. Tumor cells invade this space in response to a complex interplay of trophic factors in the local microenviroment. This attraction of tumor cells to nerves is referred to as neurotropism. The perineural space provides a conduit for tumor spread beyond the primary site of tumor occurrence. Perineural tumor growth is of two types: perineural invasion, affecting small unnamed nerves; and perineural spread, affecting larger, named nerves and presenting with clinical symptoms related to the involved nerve. Both forms of perineural tumor growth represent an adverse prognostic feature and are an essential element of the histopathologic reporting of malignancies of the head and neck region. Perineural spread is associated with decreased overall survival. Endoneurial invasion frequently accompanies perineural spread. The epineurium is more resistant to invasion and represents an important barrier to tumor spread. Immunohistochemical stains such as broad-spectrum keratin can aid in defining the proximal extent of perineural tumor spread.
PubMed: 27123388
DOI: 10.1055/s-0036-1571837 -
Cureus Jul 2018The incisive canal, also known as the nasopalatine canal, is an interosseous conduit through the anterior maxilla connecting the oral and nasal cavities. Within this... (Review)
Review
The incisive canal, also known as the nasopalatine canal, is an interosseous conduit through the anterior maxilla connecting the oral and nasal cavities. Within this canal lies the nasopalatine nerve and the vascular anastomosis between the greater palatine and sphenopalatine arteries. The embryology of the canal has led to interesting theories explaining its function. Efforts have been made to describe the morphometrics of the incisive canal by radiologic evaluation across sex and ethnicities. This paper aims to review the current literature on the embryology, anatomy, and clinical relevance of the incisive canal.
PubMed: 30280065
DOI: 10.7759/cureus.3069 -
Frontiers in Neural Circuits 2015The functions of the medial geniculate body (MGB) in normal hearing still remain somewhat enigmatic, in part due to the relatively unexplored properties of the... (Review)
Review
The functions of the medial geniculate body (MGB) in normal hearing still remain somewhat enigmatic, in part due to the relatively unexplored properties of the non-lemniscal MGB nuclei. Indeed, the canonical view of the thalamus as a simple relay for transmitting ascending information to the cortex belies a role in higher-order forebrain processes. However, recent anatomical and physiological findings now suggest important information and affective processing roles for the non-primary auditory thalamic nuclei. The non-lemniscal nuclei send and receive feedforward and feedback projections among a wide constellation of midbrain, cortical, and limbic-related sites, which support potential conduits for auditory information flow to higher auditory cortical areas, mediators for transitioning among arousal states, and synchronizers of activity across expansive cortical territories. Considered here is a perspective on the putative and unresolved functional roles of the non-lemniscal nuclei of the MGB.
Topics: Animals; Auditory Cortex; Auditory Perception; Geniculate Bodies; Thalamus
PubMed: 26582978
DOI: 10.3389/fncir.2015.00069 -
American Journal of Botany Apr 2021Gymnosperm taxa are incredibly diverse in many traits, including taxa with evergreen or deciduous leaves; broad, compound, needle-like or scale-like leaves; trees,... (Review)
Review
Gymnosperm taxa are incredibly diverse in many traits, including taxa with evergreen or deciduous leaves; broad, compound, needle-like or scale-like leaves; trees, shrubs, and lianas; and taxa with seed cones that range from fleshy to woody. Although less appreciated, xylem conduits are also diverse in structure among extant gymnosperm taxa. Within the xylem of gymnosperms, axial transport occurs predominantly via tracheids, although 10-40% of gymnosperm taxa, particularly within the Gnetophyta and Cycadophyta, also contain vessels. Gymnosperm taxa vary greatly in their inter-conduit pit structure, with different types of pit membranes and pitting arrangements. While some taxa display torus-margo bordered pits (60%), many others do not contain tori (40%), and at least some taxa without tori occur within each of the four extant phyla (Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta). Pit membrane types vary within families but appear relatively conserved within genera. Woody species with torus-bearing pit membranes occur in colder environments (lower mean annual temperature) compared to those without tori; but occurrence does not differ with mean annual precipitation. Detailed descriptions of pit membrane types are lacking for many species and genera, indicating a need for increased anatomical study. Increased knowledge of these traits could provide a unique experimental context in which to study the evolution of conduit networks, the hydraulic implications of conduit and pit structure, and the diverse structural and functional strategies utilized by gymnosperms. There are myriad potential study questions and research opportunities within this unique and diverse group of plants.
Topics: Cycadopsida; Tracheophyta; Trees; Water; Xylem
PubMed: 33861866
DOI: 10.1002/ajb2.1641 -
Journal of Clinical Medicine Sep 2023Infective endocarditis (IE) is still a life-threatening disease with frequent lethal outcomes despite the profound changes in its clinical, microbiological, imaging, and... (Review)
Review
Infective endocarditis (IE) is still a life-threatening disease with frequent lethal outcomes despite the profound changes in its clinical, microbiological, imaging, and therapeutic profiles. Nowadays, the scenario for IE has changed since rheumatic fever has declined, but on the other hand, multiple aspects, such as elderly populations, cardiovascular device implantation procedures, and better use of multiple imaging modalities and multidisciplinary care, have increased, leading to escalations in diagnosis. Since the ESC and AHA Guidelines have been released, specific aspects of diagnostic and therapeutic management have been clarified to provide better and faster diagnosis and prognosis. Surgical treatment is required in approximately half of patients with IE in order to avoid progressive heart failure, irreversible structural damage in the case of uncontrolled infection, and the prevention of embolism. The timing of surgery has been one of the main aspects discussed, identifying cases in which surgery needs to be performed on an emergency (within 24 h) or urgent (within 7 days) basis, irrespective of the duration of antibiotic treatment, or cases where surgery can be postponed to allow a brief period of antibiotic treatment under careful clinical and echocardiographic observation. Mainly, guidelines put emphasis on the importance of an endocarditis team in the handling of systemic complications and how they affect the timing of surgery and perioperative management. Neurological complications, acute renal failure, splenic or musculoskeletal manifestations, or infections determined by multiresistant microorganisms or fungi can affect long-term prognosis and survival. Not to be outdone, anatomical and surgical factors, such as the presence of native or prosthetic valve endocarditis, a repair strategy when feasible, anatomical extension and disruption in the case of an annular abscess (mitral valve annulus, aortic mitral curtain, aortic root, and annulus), and the choice of prosthesis and conduits, can be equally crucial. It can be hard for surgeons to maneuver between correct pre-operative planning and facing unexpected obstacles during intraoperative management. The aim of this review is to provide an overview and analysis of a broad spectrum of specific surgical scenarios and how their challenging management can be essential to ensure better outcomes and prognoses.
PubMed: 37762834
DOI: 10.3390/jcm12185891 -
Arteriosclerosis, Thrombosis, and... Aug 2014Perivascular adipose tissue (PVAT) directly abuts the lamina adventitia of conduit arteries and actively communicates with the vessel wall to regulate vascular function... (Review)
Review
Perivascular adipose tissue (PVAT) directly abuts the lamina adventitia of conduit arteries and actively communicates with the vessel wall to regulate vascular function and inflammation. Mounting evidence suggests that the biological activities of PVAT are governed by perivascular adipocytes, a unique class of adipocyte with distinct molecular and phenotypic characteristics. Perivascular adipocytes surrounding human coronary arteries (pericoronary perivascular adipocytes) exhibit a reduced state of adipogenic differentiation and a heightened proinflammatory state, secreting ≤50-fold higher levels of the proinflammatory cytokine monocyte chemoattractant peptide-1 compared with adipocytes from other regional depots. Thus, perivascular adipocytes may contribute to upregulated inflammation of PVAT observed in atherosclerotic human blood vessels. However, perivascular adipocytes also secrete anti-inflammatory molecules such as adiponectin, and elimination of PVAT in rodent models has been shown to augment vascular disease, suggesting that some amount of PVAT is required to maintain vascular homeostasis. Evidence in animal models and humans suggests that inflammation of PVAT may be modulated by environmental factors, such as high-fat diet and tobacco smoke, which are relevant to atherosclerosis. These findings suggest that the inflammatory phenotype of PVAT is diverse depending on species, anatomic location, and environmental factors and that these differences are fundamentally important in determining a pathogenic versus protective role of PVAT in vascular disease. Additional research into the mechanisms that regulate the inflammatory balance of perivascular adipocytes may yield new insight into, and treatment strategies for, cardiovascular disease.
Topics: Adipocytes; Animals; Atherosclerosis; Blood Vessels; Cell Differentiation; Cell Lineage; Humans; Inflammation; Inflammation Mediators; Phenotype; Prognosis; Risk Factors; Signal Transduction
PubMed: 24925977
DOI: 10.1161/ATVBAHA.114.303030 -
Cellular and Molecular Life Sciences :... Oct 2020Plant vascular development is a complex process culminating in the generation of xylem and phloem, the plant transporting conduits. Xylem and phloem arise from... (Review)
Review
Plant vascular development is a complex process culminating in the generation of xylem and phloem, the plant transporting conduits. Xylem and phloem arise from specialized stem cells collectively termed (pro)cambium. Once developed, xylem transports mainly water and mineral nutrients and phloem transports photoassimilates and signaling molecules. In the past few years, major advances have been made to characterize the molecular, genetic and physiological aspects that govern vascular development. However, less is known about how the environment re-shapes the process, which molecular mechanisms link environmental inputs with developmental outputs, which gene regulatory networks facilitate the genetic adaptation of vascular development to environmental niches, or how the first vascular cells appeared as an evolutionary innovation. In this review, we (1) summarize the current knowledge of the mechanisms involved in vascular development, focusing on the model species Arabidopsis thaliana, (2) describe the anatomical effect of specific environmental factors on the process, (3) speculate about the main entry points through which the molecular mechanisms controlling of the process might be altered by specific environmental factors, and (4) discuss future research which could identify the genetic factors underlying phenotypic plasticity of vascular development.
Topics: Arabidopsis; Arabidopsis Proteins; Phloem; Plant Growth Regulators; Plant Roots; Stress, Physiological; Xylem
PubMed: 32193607
DOI: 10.1007/s00018-020-03496-w -
The Thoracic and Cardiovascular Surgeon Dec 2022The aim of this study was to evaluate the long-term outcome and freedom from pulmonary valve replacement (PVR) after initial repair of tetralogy of Fallot (TOF).
BACKGROUND
The aim of this study was to evaluate the long-term outcome and freedom from pulmonary valve replacement (PVR) after initial repair of tetralogy of Fallot (TOF).
PATIENTS AND METHODS
The cohort of 306 patients treated between 1980 and 2017 was divided into anatomical subgroups according to the diagnosis of TOF-pulmonary stenosis, TOF-pulmonary atresia and TOF-double outlet right ventricle. Patients were treated with transannular patch (TAP), valve sparing repair (VSR), or conduits from the right ventricle to the pulmonary arteries (RVPA conduits).
RESULTS
There were 21 deaths (6.9%), 14 being hospital deaths (4.6%) after primary correction and four deaths (1.3%) occurred after PVR. One patient died after a non-cardiac operation (0.3%). There were two late deaths (0.7%). During the past 12 years no early mortality has been observed. Ninety-one patients (30.4%) received PVR after a median of 12.1 ± 7.0 years with an early mortality of 4.4% ( = 4) and no late mortality. A significant difference in freedom from reoperation after TAP, VSR, and RVPA-conduits could be identified. Multivariate analysis displayed transannular repair ( = 0.016), primary palliation ( <0.001), the presence of major aortopulmonary collateral arteries (MAPCA; = 0.023), and pulmonary valve -scores < - 4.0 ( = 0.040) as significant risk factors for PVR.
CONCLUSION
TOF repair has a beneficial long-term prognosis with low morbidity and mortality. Pulmonary valve -scores < - 4.0, transannular repair, and presence of MAPCAs are associated with earlier PVR. Non-VSRs and TOF-pulmonary atresia lead to earlier reoperation but have no negative impact on survival.
Topics: Cardiac Surgical Procedures; Humans; Infant; Pulmonary Atresia; Pulmonary Valve; Reoperation; Retrospective Studies; Tetralogy of Fallot; Treatment Outcome
PubMed: 35752174
DOI: 10.1055/s-0042-1749098 -
Heart Views : the Official Journal of... 2022Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Surgical correction has improved survival but re-intervention is often required.
INTRODUCTION
Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Surgical correction has improved survival but re-intervention is often required.
OBJECTIVES
The objective is to assess outcomes after surgical repair of TOF, long-term follow-up, and factors that influence these results.
MATERIALS AND METHODS
This is a retrospective study conducted in a tertiary care center. Records of patients diagnosed with TOF from 1992 to 2019 (37 years) were retrieved from a detailed database. Patients who underwent complete correction were grouped according to diagnosis, the technique utilized in surgical repair, need for staged repair, and syndromic association. Univariate actuarial and event-free survival analysis was performed. The endpoint for an event was death or re-intervention.
RESULTS
A total of 230 patients were diagnosed with TOF and 174 patients underwent complete surgical repair. At 40 years postoperatively, survival was 96%. Actuarial survival was independent of syndromic associations, anatomical diagnosis, type of surgery, or previous shunt. Event-free survival (EFS) survival was 8.12%. EFS was significantly worse for patients with pulmonary atresia (PA) (Hazard ratio, 4.1125; 95% confidence interval [CI], 1.2654-13.3657; < 0.0001) and for those that required homograft/conduit. The median duration for EFS was 22.73 years, 19.58 years, and 9.12 years for transannular patch (TAP), pulmonary valve-sparing (PVS), and homograft group, respectively. The survival curve for the PVS group merged with that of TAP 20 years postoperatively. Similarly, it merged at 22 years for staged versus primary repair and at 22.73 years for syndromic versus nonsyndromic patients. A weak correlation was found between age at surgery and event-free duration (cc, 0.309; < 0.0001). The need for TAP was not influenced by the previous palliation, χ(1, = 154) = 3.36, = 0.0667, or with interval to complete correction after the shunt procedure ( = 0.9672).
CONCLUSIONS
Total correction of TOF has low perioperative mortality and good long-term survival, but the need for re-interventions is high. This study demonstrated that patients requiring homograft/conduit and those with a diagnosis of PA had worse outcomes. Comparison between different surgical groups showed merging of survival curves in follow-up that signifies gradual loss of survival advantage over time.
PubMed: 36213434
DOI: 10.4103/heartviews.heartviews_77_21