Anatomy and physiology of the thoracic lymphatic system

Back to the Future II-A Comprehensive Update on the Rapidly Evolving Field of Lymphatic Imaging and Interventions

ABSTRACT

Lymphatic imaging and interventional therapies of disorders affecting the lymphatic vascular system have evolved rapidly in recent years. Although x-ray lymphangiography had been all but replaced by the advent of cross-sectional imaging and the scientific focus shifted to lymph node imaging (eg, for detection of metastatic disease), interest in lymph vessel imaging was rekindled by the introduction of lymphatic interventional treatments in the late 1990s. Although x-ray lymphangiography is still the mainstay imaging technique to guide interventional procedures, several other, often less invasive, techniques have been developed more recently to evaluate the lymphatic vascular system and associated pathologies. Especially the introduction of magnetic resonance, and even more recently computed tomography, lymphangiography with water-soluble iodinated contrast agent has furthered our understanding of complex pathophysiological backgrounds of lymphatic diseases. This has led to an improvement of treatment approaches, especially of nontraumatic disorders caused by lymphatic flow abnormalities including plastic bronchitis, protein-losing enteropathy, and nontraumatic chylolymphatic leakages. The therapeutic armamentarium has also constantly grown and diversified in recent years with the introduction of more complex catheter-based and interstitial embolization techniques, lymph vessel stenting, lymphovenous anastomoses, as well as (targeted) medical treatment options. The aim of this article is to review the relevant spectrum of lymphatic disorders with currently available radiological imaging and interventional techniques, as well as the application of these methods in specific, individual clinical situations.

Histological study of the structural layers around the esophagus in the lower mediastinum

BACKGROUND

In Japan, the transhiatal approach, including lower mediastinal lymph node dissection, is widely performed for Siewert type II esophagogastric junction adenocarcinoma. This procedure is generally performed in a magnified view using laparoscopy or a robotic system, therefore, the microanatomy of the lower mediastinum is important. However, mediastinal microanatomy is still unclear and classification of lower mediastinal lymph nodes is not currently based on fascia or other microanatomical structures.

AIM

To clarify the fascia and layer structures of the lower mediastinum and classify the lower mediastinal tissue.

METHODS

We dissected the esophagus and surrounding organs en-bloc from seven cadavers fixed in 10% formalin. Organs and tissues were then cut at the level of the lower thoracic esophagus, embedded in paraffin, and serially sectioned. Tissue sections were stained with Hematoxylin-Eosin (all cadavers) and immunostained for the lymphatic endothelial marker D2-40 (three cadavers). We observed the periesophageal fasciae and layers, and defined lymph node boundaries based on the fasciae. Lymphatic vessels around the esophagus were observed on immunostained tissue sections.

RESULTS

We identified two fasciae, A and B. We then classified lower mediastinal tissue into three areas, paraesophageal, paraaortic, and intermediate, using these fasciae as boundaries. Lymph nodes were found to be present and were counted in each area. The dorsal part of the intermediate area was thicker on the caudal side than on the cranial side in all cadavers. On the dorsal side, no blood vessels penetrated the fasciae in six of the seven cadavers, whereas the proper esophageal artery penetrated fascia B in one cadaver. D2-40 immunostaining showed lymphatic vessel connections between the paraesophageal and intermediate areas on the lateral and ventral sides of the esophagus, but no lymphatic connection between areas on the dorsal side of the esophagus.

CONCLUSION

Histological studies identified two fasciae surrounding the esophagus in the lower mediastinum and the layers separated by these fasciae were used to classify the lower mediastinal tissues.

Understanding Lymphatic Anatomy and Abnormalities at Imaging

Lymphatic abnormalities encompass a wide range of disorders spanning solitary common cystic lymphatic malformations (LMs) to entities involving multiple organ systems such as lymphangioleiomyomatosis. Many of these disorders are rare, yet some, such as secondary lymphedema from the treatment of malignancy (radiation therapy and/or lymph node dissection), affect millions of patients worldwide. Owing to complex and variable anatomy, the lymphatics are not as well understood as other organ systems. Further complicating this is the variability in the description of lymphatic disease processes and their nomenclature in the medical literature. In recent years, medical imaging has begun to facilitate a deeper understanding of the physiology and pathologic processes that involve the lymphatic system. Radiology is playing an important and growing role in the diagnosis and treatment of many lymphatic conditions. The authors describe both normal and common variant lymphatic anatomy. Various imaging modalities including nuclear medicine lymphoscintigraphy, conventional lymphangiography, and MR lymphangiography used in the diagnosis and treatment of lymphatic disorders are highlighted. The authors discuss imaging many of the common and uncommon lymphatic disorders, including primary LMs described by the International Society for the Study of Vascular Anomalies 2018 classification system (microcystic, mixed, and macrocystic LMs; primary lymphedema). Secondary central lymphatic disorders are also detailed, including secondary lymphedema and chylous leaks, as well as lymphatic disorders not otherwise easily classified. The authors aim to provide the reader with an overview of the anatomy, pathology, imaging findings, and treatment of a wide variety of lymphatic conditions. ^©RSNA, 2022.

Chylothorax associated with lymphatic reflux in a thoracic duct tributary after lung cancer surgery

Chyle leaks are attributed to damage to the thoracic duct itself or its tributaries during surgery. Chylothorax after lung cancer surgery can occur due to damaged thoracic duct tributaries; however, little is known of the mechanism involved. A 71-year-old female underwent a left upper lobectomy with hilar and mediastinal lymphadenectomy for a 1.8-cm primary squamous cell carcinoma, and developed a chylothorax a day later. Catheter lymphangiography revealed high-flow chyle leaks from a damaged thoracic duct tributary, known as a bronchomediastinal lymph trunk, due to a lymphatic reflex from the thoracic duct. Subsequently, catheter embolization of the tributary repaired the chylothorax. The potential for persistent chylothorax after lung cancer surgery and successful lymphatic intervention should be noted.

Anatomical study of the thoracic duct and its clinical implications in thoracic and pediatric surgery, a 70 cases cadaveric study

INTRODUCTION

Given the high variability and fragility of the thoracic duct, good knowledge of its anatomy is essential for its repair or to prevent iatrogenic postoperative chylothorax. The objective of this study was to define a site where the thoracic duct is consistently found for its ligation. The second objective was to define an anatomically safe surgical pathway to prevent iatrogenic chylothorax in surgery for aortic arch anomalies with vascular ring, through better knowledge of the anatomical relationships of the thoracic duct.

METHODS

Seventy adult formalin-fixed cadavers were dissected. The anatomical relationships of the thoracic duct were reported at the postero-inferior mediastinum, at levels T3 and T4.

RESULTS

The thoracic duct was consistently situated between the left anterolateral border of the azygos vein and the right border of the aorta between levels T9 and T10, whether it was simple, double, or plexiform. It was located medially, anteromedially, or posteriorly to the left subclavian artery in 51%, 21%, and 28% of the cases, respectively, at the level of T3. At T4, it was posteromedial in 27% of the cases or had no direct relationship with the aortic arch.

CONCLUSION

These results favor mass ligation of the thoracic duct at levels T9-T10 between the right border of the aorta and the azygos vein, eventually including the latter. To prevent iatrogenic postoperative chylothorax in aortic arch anomalies with vascular ring surgery, we recommend remaining strictly lateral to the left subclavian artery at the level of T3 to reach the aortic arch anomalies with vascular ring at T4.

Lymphangiography and Lymphatic Interventions

Compared with the traditional pedal lymphangiography, intranodal lymphangiography and MR lymphangiography have made imaging of the lymphatic system less challenging. Improvements in imaging and availability of newer catheters have allowed embolization of lymphatic system much more feasible that previously envisioned. In this article, we briefly review the anatomy, imaging, and current and future of lymphatic interventions.

Clinical Impact of Supraclavicular Lymph Node Involvement of Stage IIIC Non-Small Cell Lung Cancer Patients

Background and Objective: Investigations on the clinical impact of supraclavicular lymph node (SCN) involvement in stage IIIC non-small cell lung cancer (NSCLC) remain scarce. We evaluated the oncological outcomes of definitive radiochemotherapy and the clinical significance of SCN involvement. Materials and Methods: Between November 2009 and June 2019, a total of 40 patients with N3-positivity and NSCLC were evaluated. Most patients received concomitant chemotherapy, but six patients who received radiotherapy (RT) alone were also included. Twenty-one patients (52.5%) received 3D-conformal RT (3DCRT), and the remainder received intensity-modulated RT (IMRT). Results: The median follow-up duration was 10.7 months (range: 1.7-120.6 months). Median overall survival (OS) and cause-specific survival (CSS) times were 10.8 months and 16.3 months, respectively. Among the 40 patients, 17 (42.5%) had SCN involvement. SCN involvement negatively affected progression-free survival (hazard ratio (HR): 2.08, 95% confidence interval (CI): 1.04-4.17, p = 0.039) and local control (HR: 3.05, 95% CI: 1.09-8.50, p = 0.034). However, IMRT use was correlated with higher local control (HR: 0.28, 95% CI: 0.09-0.86, p = 0.027). Grade ≥3 esophagitis and pneumonitis accounted for 7.5% and 15.0% of all cases, respectively. A higher RT dose (mean dose: 66.6 vs. 61.7 Gy) was significantly correlated with grade ≥3 pneumonitis (p = 0.001). RT modality was a significant factor (p = 0.042, five of six cases occurred in the IMRT group). Conclusions: SCN involvement could negatively affect oncologic outcomes of stage IIIC NSCLC patients. High-dose irradiation with IMRT could increase local control but may cause lung toxicities.

Lymphatic Pathways of the Thorax: Predictable Patterns of Spread

OBJECTIVE. This article reviews thoracic lymphatic pathways and tributaries, discusses lymphatic anatomic variants and their clinical implications, and emphasizes common patterns of thoracic lymphadenopathy from extrapulmonary malignancies. CONCLUSION. Recognition of common patterns and pathways of thoracic lymphatic drainage can help identify the site of tumor origin and allow a more focused examination of disease extent, both of which are important for disease prognosis and management.

Nontraumatic Chylothorax: Nonenhanced MR Lymphography

Chylothorax is a rare cause of pleural effusion, secondary to accumulation of lymph in the pleural space. Diagnosis is based on the triglyceride and cholesterol content of pleural fluid obtained with thoracentesis. Because the lymphatic system plays an essential role in fat absorption and immune response, lymphatic leak associated with chylothorax may cause life-threatening malnutrition and immunodeficiency. Chylothorax is usually described as traumatic or nontraumatic. The main cause of chylothorax is traumatic, typically postsurgical, secondary to iatrogenic direct puncture of the thoracic duct during thoracic surgery. Causes of nontraumatic chylothorax include a wide range of differential diagnoses. Lymphoma and thoracic malignancies are the most common causes and are responsible for chylothorax by extrinsic compression or invasion of the thoracic duct. Other rare causes include primary and secondary diffuse lymphatic diseases, responsible for chylothorax by lymphatic vessel wall dysfunction. Imaging the lymphatic system remains a challenge in the days of modern imaging. Nonenhanced MR lymphography is a noninvasive technique based on heavily T2-weighted sequences, thus enabling visualization of the lymphatic circulation. This technique allows diagnosis and differential diagnosis, evaluation of disease severity, and guidance of therapeutic management in nontraumatic chylothorax. Furthermore, it may offer radiologic classification of primary lymphatic diseases on the basis of morphologic features of lymphatic vessels. The authors describe the anatomy and physiology of the thoracic lymphatic system, present the technique of nonenhanced MR lymphography, and discuss pathophysiologic mechanisms and imaging features in different causes of nontraumatic chylothorax. ^©RSNA, 2020.

Typical CT Features of Intrapulmonary Lymph Nodes: A Review

Several studies investigated the appearance of intrapulmonary lymph nodes (IPLNs) at CT with pathologic correlation. IPLNs are benign lesions and do not require follow-up after initial detection. There are indications that IPLNs represent a considerable portion of incidentally found pulmonary nodules seen at high-resolution CT. The reliable and accurate identification of IPLNs as benign nodules may substantially reduce the number of unnecessary follow-up CT examinations. Typical CT features of IPLNs are a noncalcified solid nodule with sharp margins; a round, oval, or polygonal shape; distanced 15 mm or less from the pleura; and most being located below the level of the carina. The term perifissural nodule (PFN) was coined based on some of these characteristics. Standardization of those CT criteria are a prerequisite for accurate nodule classification. However, four different definitions of PFNs can currently be found in the literature. Furthermore, there is considerable variation in the reported interobserver agreement, malignancy rate, and prevalence of PFNs. The purpose of this review was to provide an overview of what is known about PFNs. In addition, knowledge gaps in defining PFNs will be discussed. A decision tree to guide clinicians in classifying nodules as PFNs is provided. Supplemental material is available for this article. © RSNA, 2020 See also the commentary by White and Rubin in this issue.

Anatomical variations in distal portion of the thoracic duct-A systematic review

The objective of this study was to identify and analyze the anatomical variations in the termination of the thoracic duct (TD) in cadavers or patients by anatomical dissections and surgical or radiological procedures for better knowledge of the interindividual variations through a systematic review. The search strategy included PubMed and reference tracking. Studies were identified by searching the electronic Medline databases. The search terms included "TD," "Jugular Vein," "Subclavian Vein," or "Cervical," and the protocol used is reported herein. These search results yielded 20 qualitative review articles out of the 275 articles consulted. We collected all the important data from these 20 articles with 1,352 TD analyzed by varying sources in our search. Regarding the characteristics of the studies and the anatomy of the TD, the results were heterogeneous. The TD most commonly terminates in the internal jugular vein in 54.05% of cases (95% confidence interval [CI]: 54.03; 54.07), in the jugular-venous angle in 25.79% (95% CI: 25.77; 25.81), and in the subclavian vein in 8.16% of cases (95% CI: 8.14;8.18). Other terminations were found in 12% of cases. This systematic review provided an overview of the variations in the distal portion of the TD. This study can be helpful for surgeons in selecting the most appropriate methods to achieve successful surgical results and avoid complications, such as chylothorax; it also offers detailed information on the cervical termination of the TD in new diagnostic and therapeutic methods involving the TD. Clin. Anat. 32:99-107, 2019. © 2019 Wiley Periodicals, Inc.

Achieving adequate lymph node dissection in treating esophageal squamous cell carcinomas by radical lymphadenectomy: Beyond the scope of numbers of harvested lymph nodes

Previous studies have recommended harvesting a large number of lymph nodes (LNs) to improve the survival of patients with esophageal squamous cell carcinoma (ESCC). These studies or clinical guidelines focus on the total harvested LNs during lymphadenectomy; however, the extent of LN dissection (LND) required in patients with ESCCs remains controversial. The present study proposed a novel individualized adequate LND (ALND) strategy to compliment current guidelines to improve individualized therapeutic efficacy. For N0 cases, ALND was defined as an LN harvest of >55% of the LNs from nodal zones adjacent to the tumor location; and for N⁺ cases, ALND was defined as 8, 8, 8, 8 or 16 LNs dissected from the involved cervical, upper, middle, lower and celiac zones, respectively. Retrospective analysis of the ESCC cohort revealed that the ALND was associated with improved patient survival [hazard ratio (HR)=0.45 and 95% CI=0.30–0.66)]. Stratified analyses revealed that the protective role of ALND was prominent, with the exception of higher pN⁺ staged (pN2-3) cases (HR=0.52, 95% CI=0.23–1.18). Furthermore, ALND was associated with improved survival in local diseases (T1-3/N0-1; HR=0.50, 95% CI=0.30–0.84) and locally advanced diseases (T4/Nany or T1-3/N2-3; HR=0.32, 95% CI=0.15–0.68). These findings suggested that the proposed ALND strategy may effectively improve the survival of patients with ESCC.

Prognostic Factors in Stage IIB Non-Small Cell Lung Cancer according to the 8th Edition of TNM Staging System

Background

The purposes of this study were to evaluate the appropriateness of the stage migration of stage IIA non-small cell lung cancer (NSCLC) in the seventh edition of the tumor, node, and metastasis classification for lung cancer to stage IIB lung cancer in the eighth edition, and to identify prognostic factors in patients with eighth-edition stage IIB disease.

Methods

Patients with eighth-edition stage IIB disease were subclassified into those with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease, and their recurrence-free survival and disease-specific survival rates were compared. Risk factors for recurrence after curative resection were identified in all included patients.

Results

Of 122 patients with eighth-edition stage IIB NSCLC, 101 (82.8%) had seventh-edition stage IIA disease and 21 (17.2%) had seventh-edition stage IIB disease. Nonsignificant differences were observed in the 5-year recurrence-free survival rate and the 5-year disease-specific survival rate between the patients with seventh-edition stage IIA disease and those with seventh-edition stage IIB disease. Visceral pleural invasion was a significant risk factor for recurrence in patients with eighth-edition stage IIB NSCLC.

Conclusion

The stage migration from seventh-edition stage IIA NSCLC to eighth-edition stage IIB NSCLC was appropriate in terms of oncological outcomes. Visceral pleural invasion was the only prognostic factor in patients with eighth-edition stage IIB NSCLC.

500 Million Alveoli from 30,000 Feet: A Brief Primer on Lung Anatomy

The lungs are a complex organ that fulfill multiple life-sustaining roles including transfer of oxygen and carbon dioxide between the ambient environment and the bloodstream, host defense, and immune homeostasis. As in any biological system, an understanding of the underlying anatomy is prerequisite for successful experimental design and appropriate interpretation of data, regardless of the precise experimental model or procedure in use. This chapter provides an overview of human lung anatomy focused on the airways, the ultrastructure or parenchyma of the lung, the pulmonary vasculature, the innervation of the lungs, and the pulmonary lymphatic system. We will also discuss notable anatomic differences between mouse and human lungs.

Anatomy of lymphatic drainage of the esophagus and lymph node metastasis of thoracic esophageal cancer

The lymphatic drainage of the inner layers (mucosa and submucosa) and the outer layers (muscularispropria and adventitia) of the thoracic esophagus is different. Longitudinal lymphatic vessels and long drainage territory in the submucosa and lamina propria should be the bases for bidirectional drainage and direct drainage to thoracic duct and extramural lymph nodes (LN). The submucosal vessels for direct extramural drainage are usually thick while lymphatic communication between the submucosa and intermuscular area is usually not clearly found, which does not facilitate transversal drainage to paraesophageal LN from submucosa. The right paratracheal lymphatic chain (PLC) is well developed while the left PLC is poorly developed. Direct drainage to the right recurrent laryngeal nerve LN and subcarinal LN from submucosa has been verified. Clinical data show that lymph node metastasis (LNM) is frequently present in the lower neck, upper mediastinum, and perigastric area, even for early-stage thoracic esophageal cancer (EC). The lymph node metastasis rate (LNMR) varies mainly according to the tumor location and depth of tumor invasion. However, there are some crucial LN for extramural relay which have a high LNMR, such as cervical paraesophageal LN, recurrent laryngeal nerve LN, subcarinal LN, LN along the left gastric artery, lesser curvature LN, and paracardial LN. Metastasis of thoracic paraesophageal LN seems to be a sign of more advanced EC. This review gives us a better understanding about the LNM and provides more information for treatments of thoracic EC.

A new classification of lymph node metastases according to the lymph node stations for predicting prognosis in surgical patients with esophageal squamous cell carcinoma

Lymph node metastasis (LNM) is one of the major prognostic factors for esophageal squamous cell carcinoma (ESCC). However there is no consensus regarding the prognostic significance of the location of LNM. Therefore, a novel classification was proposed to identify the lymph node (LN) stations which may be useful in predicting prognosis. A total of 260 ESCC patients were enrolled in this prospective study. The prognostic values of LNM in different lymph node (LN) stations were evaluated by random survival forests (RSF). Their prognostic significance was examined by Cox regression and receiver operating characteristic curve (ROC). The three most frequently involved LN stations were station 16 (24.49%), station 1 (22.22%) and station 2 (21.05%). Stations 1, 2, 8M, 8L and 16 were grouped as dominant LN stations (DLNS) which showed higher values in predicting overall survival (OS) and disease-free survival (DFS) than the remaining LN stations, which we define as non-dominant LN stations (N-DLNS). LNM features of DLNS (number of positive LN stations, number of positive LNs and LN ratio), but not those from N-DLNS, served as independent prognostic factors (P<0.05) whenever used alone or when combined with factors from N-DLNS. Furthermore, the area under ROC indicated that DLNS is a more accurate prediction than N-DLNS (P<0.05). This study demonstrated the value of LNM in DLNS in predicting prognosis in surgical ESCC patients, which outperformed those from N-DLNS. Therefore, the method of dominant and non-dominant classification may serve as an additional parameter to improve individualized therapeutic strategies.

Intestinal lymph as a readout of meal-induced GLP-1 release in an unrestrained rat model

Intestinal lymph supposedly provides a readout for the secretion of intestinal peptides. We here assessed how mesenteric lymph duct (MLD) lymph levels of glucagon-like peptide (GLP-1), insulin, and metabolites [glucose and triglycerides (TG)] evolve after isocaloric high- and low-fat diet (HFD and LFD) meals and how they compare with hepatic portal vein (HPV) plasma levels. Moreover, we examined the effects of intraperitoneally administered GLP-1 (1 or 10 nmol/kg) on these parameters. At 20 min after the HFD meal onset, GLP-1 levels were higher in MLD lymph than in HPV plasma. No such difference occurred with the LFD meal. Intraperitoneal injections of 10 nmol/kg GLP-1 before meals enhanced the meal-induced increases in MLD lymph and HPV plasma GLP-1 levels except for the MLD lymph levels after the HFD meal. Intraperitoneal injection of 1 nmol/kg GLP-1 only increased HPV plasma GLP-1 levels at 60 min after the HFD meal. GLP-1 injections did not increase the MLD lymph or HPV plasma GLP-1 concentrations beyond the physiological range, suggesting that intraperitoneal GLP-1 injections can recapitulate the short-term effects of endogenous GLP-1. Dipeptidyl peptidase IV (DPP-IV) activity in MLD lymph was lower than in HPV plasma, which presumably contributed to the higher levels of GLP-1 in lymph than in plasma. Insulin and glucose showed similar profiles in MLD lymph and HPV plasma, whereas TG levels were higher in lymph than in plasma. These results indicate that intestinal lymph provides a sensitive readout of intestinal peptide release and potential action, in particular when fat-rich diets are consumed.

Risk factors of lymph node metastasis in lung squamous cell carcinoma of 3 cm or less in diameter

Through literature review we cannot find an efficient risk factor of lymph node metastasis in lung squamous cell carcinoma (SCC). This study aimed to investigate the risk factors of pathological lymph node status in patients with lung SCC of 3 cm or less in diameter, to provide some reference for the fellow surgeons in the decision of operative option.In total, we analyzed 154 patients with lung SCC of 3 cm or less in diameter who underwent lobectomy or bilobectomy or pneumonectomy with systematic lymph node dissection. The relationship between lymph node status and clinical characteristics were examined.Lymph node metastases were present in 48 patients (31.2%) of the study subjects. Multivariate analysis indicated that, age <60 years old (P = .007), tumor location of central-type (P = .003), tumor long axis >2 cm but ≤3 cm (P = .047) were associated with lymph node metastasis, and their odd ratios (OR) were 3.120, 3.359, and 5.196, respectively. Group analysis of the 74 peripheral lung SCC showed that those with the tumor long axis ≤2 cm had a lower rate of lymph node metastasis (7.9% vs 27.8%, P = .025).Age <60 years old, tumor location of central-type, and tumor long axis >2 cm but ≤3 cm are risk factors of lymph node metastasis in lung SCC. Systematic lymph node dissection or sampling is recommended when tumor central-type location and/or long axis >2 cm in lung SCC are present.

Models of Lung Transplant Research: a consensus statement from the National Heart, Lung, and Blood Institute workshop

Lung transplantation, a cure for a number of end-stage lung diseases, continues to have the worst long-term outcomes when compared with other solid organ transplants. Preclinical modeling of the most common and serious lung transplantation complications are essential to better understand and mitigate the pathophysiological processes that lead to these complications. Various animal and in vitro models of lung transplant complications now exist and each of these models has unique strengths. However, significant issues, such as the required technical expertise as well as the robustness and clinical usefulness of these models, remain to be overcome or clarified. The National Heart, Lung, and Blood Institute (NHLBI) convened a workshop in March 2016 to review the state of preclinical science addressing the three most important complications of lung transplantation: primary graft dysfunction (PGD), acute rejection (AR), and chronic lung allograft dysfunction (CLAD). In addition, the participants of the workshop were tasked to make consensus recommendations on the best use of these complimentary models to close our knowledge gaps in PGD, AR, and CLAD. Their reviews and recommendations are summarized in this report. Furthermore, the participants outlined opportunities to collaborate and directions to accelerate research using these preclinical models.

Biological voyage of solid lipid nanoparticles: a proficient carrier in nanomedicine

This review projects the prospects and issues faced by solid lipid nanoparticles (SLNs) in current scenarios, specially related to its clinical implementation and effectiveness. We re-examine the basic concept of biobehavior and movement of SLNs as a nanomedicine carrier. The extensive survey of the uptake and absorption mechanism from different routes, distribution pattern, targeting efficiency, effect of surface functionalization on biodistribution, elimination pathways and toxic effects have been documented. In general, the objective of this review is to boost our knowledge about the interaction of SLNs with the bioenvironment, their movement in, and effect on, a living system and future prospects.

Esophageal cancer: anatomic particularities, staging, and imaging techniques

Cancer of the esophagus is a tumor with aggressive behavior that is usually diagnosed in advanced stages. The absence of serosa allows it to spread quickly to neighboring mediastinal structures, and an extensive lymphatic drainage network facilitates tumor spread even in early stages. The current TNM classification, harmonized with the classification for gastric cancer, provides new definitions for the anatomic classification, adds non-anatomic characteristics of the tumor, and includes tumors of the gastroesophageal junction. Combining endoscopic ultrasound, computed tomography, positron emission tomography, and magnetic resonance imaging provides greater accuracy in determining the initial clinical stage, and these imaging techniques play an essential role in the selection, planning, and evaluation of treatment. In this article, we review some particularities that explain the behavior of this tumor and we describe the current TNM staging system; furthermore, we discuss the different imaging tests available for its evaluation and include a diagnostic algorithm.

Lymphatic Stomata in the Adult Human Pulmonary Ligament

BACKGROUND

Lymphatic stomata are small lymphatic openings in the serosal membrane that communicate with the serosal cavity. Although these stomata have primarily been studied in experimental mammals, little is known concerning the presence and properties of lymphatic stomata in the adult human pleura. Thus, adult human pleurae were examined for the presence or absence of lymphatic stomata.

METHODS AND RESULTS

A total of 26 pulmonary ligaments (13 left and 13 right) were obtained from 15 adult human autopsy cases and examined using electron and light microscopy. The microscopic studies revealed the presence of apertures fringed with D2-40-positive, CD31-positive, and cytokeratin-negative endothelial cells directly communicating with submesothelial lymphatics in all of the pulmonary ligaments. The apertures' sizes and densities varied from case to case according to the serial tissue section. The medians of these aperture sizes ranged from 2.25 to 8.75 μm in the left pulmonary ligaments and from 2.50 to 12.50 μm in the right pulmonary ligaments. The densities of the apertures ranged from 2 to 9 per mm(2) in the left pulmonary ligaments and from 2 to 18 per mm(2) in the right pulmonary ligaments. However, no significant differences were found regarding the aperture size (p=0.359) and density (p=0.438) between the left and the right pulmonary ligaments.

CONCLUSIONS

Our study revealed that apertures exhibit structural adequacy as lymphatic stomata on the surface of the pulmonary ligament, thereby providing evidence that lymphatic stomata are present in the adult human pleura.