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[Selected problems in the evolution of scientific examination of the lymphatic system of the larynx and the surrounding region presented for clinical purposes].

The most important results of the morphological research of the lymphatic system of the larynx with surrounding tissues were presented. Based on section specimens of larynx the topography of the lymphatic system was described. We also described changes in the lymphatic system after radiation and after manifestation of squamous cell carcinoma in this region. We concluded that the main causes of our clinical adversities in treatment of larynx cancer were lymphatic stasis, cancer embolism of small nodes between mucosa and deep lymph nodes of the neck. We also studied over the methods of intravital examinations of the neck's lymphatic system.

Carcinoma, Squamous Cell↗

Diagnostic evaluation of the pelvic and abdominal lymphatic system.

Evaluation of the pelvic and abdominal lymphatic systems is the subject of renewed interest by radiologists, radiotherapists, surgeons and medical oncologists. The primary reason for this interest has been the rapid advance of diagnostic imaging technology, particulary in ultrasonography and computerized tomography (CT). Another reason is the realization that with some neoplasms, particularly gynecologic neoplasms, there has been little progress in long-term survival in spite of aggressive local management. A possible explanation for this is "understaging" of neoplasms by previous radiologic procedures. Although lymphangiography has a proved and well-defined place in the diagnostic regimen, it remains tedious, time-consuming and invasive. Gray-scale ultrasound and CT have been widely used for several years and their role, limitations and relationship to lymphangiography have become established. The purpose of this monograph is to provide a short review of the lymphatic system and lymphangiogram, with particular attention to the recent radiologic literature. The role and limitations of the various diagnostic modalities are discussed and the lymphatic drainage and common pelvic neoplasms (as approached in the recent literature) are reviewed. No attempt has been made to define the lymphatic drainage of abdominal visceral organs.

Female↗

Role of a lymphatic system in glucose absorption and the accompanying microvascular hyperemia.

In this study we evaluated the importance of a functional intestinal lymphatic system on changes in arteriolar and venular blood oxygen content, vasodilation, and elevation of venous blood osmolarity during glucose absorption. Glucose absorption was associated with a doubling of the arteriovenous oxygen difference [(A-V)O2], a 50 mosM increase in venous blood osmolarity, and 17% dilation of the intermediate-diameter arterioles. After the lymph vessels were mechanically blocked with mineral oil, glucose absorption again doubled the (A-V)O2, indicating that glucose was absorbed without a functional lymphatic system. Furthermore, venous blood osmolarity and arteriolar diameter increased similarly with and without a functional lymphatic system. This study indicates that even though the lymphatic system likely facilitates distribution of hypertonic material in the bowel wall during absorption, blockade of the lymphatics did not appreciably hinder vasodilation, glucose absorption, changes in intravascular oxygen content, or the elevation of tissue hyperosmolarity, as judged by the tonicity of the venular blood. Therefore, passage of materials absorbed or released in the mucosa to the submucosa through venular blood flow may be very important to the mechanism of absorptive hyperemia.

Animals↗

The innate reaction of the human skin lymphatic system to foreign and self-antigens.

The skin lymphatic system is the constitutive anatomical organization of the innate immune system. It reacts immediately to penetrating foreign antigens and presents them to the organized lymphoid tissue, where subsequently the adaptive immune response develops. Both phylogenetically and ontogenetically, defense mechanisms ascribed to the lymphatic system developed earlier than the nutritive function of blood elements. Resident and migrating immune cells, regulatory proteins, neuroregulatory factors, complement components, coagulation factors, and antimicrobial peptides react immediately to foreign antigens. Moreover, they most likely participate in elimination of shed autoantigens. Thus far, the knowledge of specific events and mechanisms operative in the innate response is still in a premordial stage. Further studies will elucidate not only how we immediately recognize what is nonself and react to it but also learn more about evolution of local immune memory in the immune and parenchymatous cells.

Antigens↗

On the active vascular absorption of plasma proteins from tissue: rethinking the role of the lymphatic system.

According to Starling's hypothesis, the osmotic pressure of plasma proteins in the capillary is the principal force for fluid absorption. The leakage of plasma proteins from capillaries to tissue during 24 h accounts for the total amount of plasma proteins in the vascular system. The same amount must therefore be reabsorbed by the lymphatic system, which is considered to be the sole absorber of proteins from tissue. However, it is a well-established routine in all kinds of organ transplantation to not restore the lymphatic system of the transplant. Experience has shown that this reconstruction is unnecessary, which consequently implies that the lymphatics are not of crucial importance for the survival of the organ. Inevitably, we must therefore question the vital role that the lymphatic system has been attributed in maintaining homeostasis as the sole absorber of proteins. Instead, it is proposed that the major part of plasma proteins in tissue is actively absorbed by the capillaries.

Absorption↗

Ultrastructural and seasonal aspects of the kidney lymphatic system of hibernating animals.

The kidney lymphatic system of bat, dormouse and marmot consists of intraparenchymal (interlobar, arcuate, interlobular) and extraparenchymal (capsular) vessels sharing common ultrastructural aspects. We did not observe medullary lymphatics. The qualitative and quantitative seasonal changes in the ultrastructure of the lymphatic endothelium represent not only a species-linked feature but also (and mainly) an evident seasonal fluctuation in lymph formation. Furthermore, these ultrastructural changes emphasize the important role played by the different mechanisms involved in the translymphatic movement of proteins and interstitial fluid with particular regard to the 'vesicular route' and intraendothelial channels.

Animals↗

Structure, function, and molecular control of the skin lymphatic system.

The mechanisms of angiogenesis have been studied extensively over the past years. The focus, however, has been almost exclusively on blood vessels, whereas little effort has been directed toward understanding lymphangiogenesis and the role of lymphatic vessels in physiology and pathology. The lymphatic system, acting in concert with the blood vascular system, is of fundamental importance in maintaining tissue homeostasis, and disorders of the lymphatic system are common, often resulting in chronic, disabling conditions. This overview summarizes the most important aspects of the structure and function of the lymphatic system with emphasis on the skin lymphatic vasculature and the differences between blood and lymphatic vessels. Special attention has been given to the methods employed in research of the lymphatic system. Finally, we describe molecular mechanisms involved in the regulation of lymphangiogenesis. Vascular endothelial growth factor and vascular endothelial growth factor-C, expressed by distinct skin cell populations, play an important role in the molecular control of skin angiogenesis and lymphangiogenesis.

Humans↗

Phylogeny and ontogeny of the lymphatic stomata connecting the pleural and peritoneal cavities with the lymphatic system--a review.

This paper reviews the phylogeny and ontogeny of "lymphatic stomata" through which fluids and cells in the pleural and peritoneal cavities enter the lymphatic system. In amphibians, the pleuroperitoneal cavity is connected through numerous pores with the wide subvertebral lymphatic sinus corresponding to the thoracic duct in mammals. In reptiles, direct connections of the pleural and peritoneal cavities with the lymphatic system have been reported. In mammals, the pleural and peritoneal cavities are directly connected with lymphatics through lymphatic stomata. How do lymphatic stomata develop in mammals? In the rat, distinct lymphatics are noted in the subpleural space of the diaphragm periphery in 16 days old embryo. With age, the supleural lymphatics increase and form a polygonal network. They show a tubular appearance and possess many valves. Some of them become endowed with smooth muscle cells. In 19 days old embryos, some lymphatics appear in the subperitoneal space of the diaphragm. They extend centripetally and form many lateral projections that later elongate and connect with those from adjacent lymphatics, thus forming a lattice-like network or "lymphatic lacunae". During early postnatal days, the lymphatic lacunae project many bulges that subsequently come into contact with the pores among mesothelial cells lining the diaphragmatic peritoneum, thus forming lymphatic stomata. They increase until postnatal week 10. The lymphatic stomata in the costal pleura also develop during early postnatal days.

Aging↗

Functional morphology of the lymphatic system in the monkey diaphragm.

A morphological study of the lymphatic system in the diaphragm of adult Japanese monkeys was carried out using intraperitoneal injection with India ink, light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques. For SEM examination of the subperitoneal connective tissue, the peritoneal mesothelium was stripped by either the NaOH/sonication microdissection techniques or the NaOH digestion method. Light microscopy of 1 micron Epon sections and TEM of thin sections demonstrated that lymphatic capillaries were distributed in the subperitoneal connective tissue of the muscular and tendinous portions. Gaps (stomata) between neighboring cells of the peritoneal mesothelium were occasionally encountered. In SEM observations, stomata with oval shapes and various sizes were abundantly seen in the peritoneal mesothelium, but were absent from the pleural mesothelium. It deserves particular note that a large number of foramina were detected in the subperitoneal connective tissue. The cluster of the foramina was similar in appearance to the "macula cribriformis" depicted by KIHARA (1956). Carbon particles injected into the monkey peritoneal cavity passed through the peritoneal stomata and then the macula cribriformis, ultimately to enter the lymphatic capillaries. This paper also discusses the functional implication of the lymphatic system in the diaphragm.

Animals↗

Low doses of hepadnavirus induce infection of the lymphatic system that does not engage the liver.

Woodchuck hepatitis virus (WHV), which is closely related to human hepatitis B virus and is considered to be principally hepatotropic, invades the host's lymphatic system and persists in lymphoid cells independently of whether the infection is symptomatic and serologically evident or concealed. In this study, we show, with the woodchuck model of hepatitis B, that hepadnavirus can establish an infection that engages the lymphatic system, but not the liver, and persists in the absence of virus serological markers, including antiviral antibodies. This primary occult infection is caused by wild-type virus invading the host at a quantity usually not greater than 10(3) virions. It is characterized by trace virus replication progressing in lymphatic organs and peripheral lymphoid cells that, with time, may also spread to the liver. The infection is transmissible to virus-naive hosts as an asymptomatic, indefinitely long, occult carriage of small amounts of biologically competent virus. In contrast to residual silent WHV persistence, which normally endures after the resolution of viral hepatitis and involves the liver, primary occult infection restricted to the lymphatic system does not protect against reinfection with a large, liver-pathogenic WHV dose; however, the occult infection is associated with a swift recovery from hepatitis caused by the superinfection. Our study documents that the lymphatic system is the primary target of WHV infection when small quantities of virions invade a susceptible host.

Animals↗

Development of the avian lymphatic system.

Recently, highly specific markers of the lymphatic endothelium have been found enabling us to reinvestigate the embryonic origin of the lymphatics. Here we present a review of our studies on the development of the lymphatic system in chick and quail embryos. We show that the lymphatic endothelium is derived from two sources: the embryonic lymph sacs and mesenchymal lymphangioblasts. Proliferation studies reveal a BrdU-labeling index of 11.5% of lymph sac endothelial cells by day 6.25, which drops to 3.5% by day 7. Lymphangioblasts are able to integrate into the lining of lymph sacs. Lymphatic endothelial cells express the vascular endothelial growth factor (VEGF) receptors-2 and -3. Their ligand, VEGF-C, is expressed almost ubiquitously in embryonic and fetal tissues. Elevated expression levels are found in the tunica media of large blood vessels, which usually serve as major routes for growing lymphatics. The homeobox gene, Prox1, is expressed in lymphatic but not in blood vascular endothelial cells throughout all stages examined, namely, in developing lymph sacs of day 6 embryos and in lymphatics at day 16. Experimental studies show the existence of lymphangioblasts in the mesoderm, a considerable time before the development of the lymph sacs. Lymphangioblasts migrate from the somites into the somatopleure and contribute to the lymphatics of the limbs. Our studies indicate that these lymphangioblasts already express Prox1.

Animals↗

Identification of the regional lymphatic system of the gallbladder by vital staining.

In 21 patients with biliary tract cancer dye was injected into the lymphatic system of the gallbladder to determine the extent of its regional lymph nodes. A volume of 0.1-0.3 ml 1 per cent indigo carmine solution was injected directly into lymphatic vessels of the gallbladder in eight patients and into lymph nodes (cystic node or pericholedochal nodes) in 13 patients during radical surgery for biliary tract cancer. The lymphatic system was visualized in a total of 14 patients. The dye descended around the bile duct, flowed into the cystic node, the pericholedochal nodes and the lymph nodes posterior to the head and neck of the pancreas, and finally reached the interaortocaval nodes adjacent to the left renal vein. The stained lymphatic tissue was regarded as the regional lymphatic system of the gallbladder. These nodes should be completely resected during radical surgery for gallbladder cancer.

Bile Duct Neoplasms↗

[Transformation of the kidney lymphatic system in clinical pathology].

The nature of transformations in the renal lymphatic system in the clinical pathology of the kidneys, mainly in the final stage of chronic glomerulonephritis, hypertension, atherosclerosis, hydronephrotic transformation (45 autopsy kidneys) is demonstrated. The controls consisted of kidneys from patients dying with non-renal pathology (12 organs). In the final stages of the above diseases progressive reduction of the intraorgan lymphatic capillaries and vessels with simultaneous marked vascularization of the fibrous renal capsule due to an increase in the amount of lymphatic capillaries (their growth) and formation of new abducting lymph stems, numerous anastomoses between them, as well as distention in the vessel lumens and the development of varicosis of the wall. These morphological changes indicate high plastic properties of the lymphatic system and its role in the retention of the renal function in developing "local" lymph congestions in the organ because of outgrowth of the connective tissue. On the other hand, they are universal and reflect the time course of the progress.

Adult↗

Lymphatic system of the mouse diaphragm: morphology and function of the lymphatic sieve.

BACKGROUND: The diaphragm has a unique system that collects peritoneal fluid and carries it into the lymphatic system. However, our understanding of the morphology and function of this system is still incomplete. METHODS: Twelve C57BL/6 mice of 13 to 25 weeks of age were used without regard to sex. In one series of experiments, the diaphragm was isolated and fixed 10-15 minutes after injection of india ink into the peritoneal cavity and then the peritoneal mesothelium was peeled off from the submesothelial connective tissue. The lymphatic vessels attached to the mesothelial strip were examined by scanning electron microscopy. The diaphragm was also observed in plastic-embedded semithin and ultrathin sections. In another series of experiments, the diaphragm was stained by 5'-nucleotidase histochemistry (Wachstein and Meizel, 1957a. Am. J. Clin. Pathol., 27:13-23), and several microdrops of india ink were placed on the peritoneal or pleural surface to reveal the profile of the lymphatic vessels. RESULTS: The lymphatic vessels on the peritoneal side of the diaphragm were flattened. They usually ranged from several to 100 microns in width and from close to zero to a few micrometers in thickness. In other words, they formed extremely flat lumina, differing from the more usual tubular lymphatic vessels. Several lymphatic vessels extended radially and parallel to one another from the central tendon to the thoracic wall, with numerous connecting branches, forming an area of lymphatic vessels. The india ink that had been injected intraperitoneally and the staining with 5'-nucleotidase revealed that there were seven to nine such lymphatic areas in one hemisphere of the diaphragm. The lymphatic areas spread in parallel with the peritoneal surface of the diaphragm and all the areas together appeared to occupy more than half the surface area of the sternocostal part of the diaphragm. Each area was a relatively distinct functional unit with respect to the draining of india ink. Microdrops of india ink placed on the pleural surface did not enter the lymphatic vessels, while those placed on the peritoneal surface immediately entered the peritoneal lymphatic vessels and migrated to the pleural lymphatic vessels via the transmuscular lymphatic branches. CONCLUSIONS: The peritoneal lymphatic vessels of the diaphragm have extremely flat lumina that spread in parallel with the peritoneal surface of the diaphragm and form a lymphatic sieve that covers approximately half or more of the surface area of the sternocostal region for drainage of fluid and particulate matter from the peritoneal cavity. The lymphatic system has been characterized by the presence of openings (= stomata) to the peritoneal cavity and the amplitude of the lumina (= lacunae). However, the fundamental characteristic of the system is the extremely flat lumen (= vadum), which facilitates the formation of the lymphatic sieve.

Animals↗

Lymphatic system as a path underlying the spread of lung and gut injury after intestinal ischemia/reperfusion in rats.

We investigated in rats the influence of the lymphatic system and of tumor necrosis factor (TNF) on the lung inflammation resulting from intestinal ischemia/reperfusion (I/R) performed by 45-min occlusion of the superior mesenteric artery followed by 2 h of reperfusion. A group of rats had the thoracic lymph duct ligated before I/R. In lungs, intestinal I/R evoked a significant neutrophil recruitment, and enhanced microvascular permeability, in addition to generation of TNF in serum. In the gut, there was lowered lactate dehydrogenase (LDH) activity and increased microvascular permeability. Upon lymph duct ligation, I/R rats had a significant reduction of pulmonary neutrophil recruitment and plasma extravasation, in addition to high amounts of TNF in the lymph, contrasting with undetectable levels in the serum. In addition, LDH gut levels in these animals were close to basal values; there was also some (yet significant) reduction of microvascular permeability, suggesting that the ligation of the lymphatic duct exerted some degree of protection against the intestinal injury caused by I/R. In I/R rats, the treatment with pentoxifylline (PTX) reduced TNF in serum and blunted other lung alterations. The gut alterations caused by intestinal I/R were largely blocked by PTX. On the other hand, in I/R rats with lymph duct ligation, PTX exacerbated the reduction of pulmonary neutrophil recruitment, but did not affect pulmonary and intestinal microvascular permeabilities. Similarly, intestinal LDH activity and serum TNF levels were unaffected. Overall, our data show that the pulmonary and gut injuries induced by intestinal I/R are partially dependent on TNF, which is conceivably generated in the injured gut tissue due to intestinal I/R and carried by the lymphatic system. Thus, the mesenteric lymphatic drainage seems to play a role as a path modulator of the pulmonary and intestinal dysfunctions that follow a gut trauma.

Animals↗