The early development of the lymphatic system in mouse embryos.

The early development of the lymphatic system was studied in embryos of an inbred strain of the laboratory mouse. During the first stage of its development the system is represented by a more or less regular series of small and blind-ending outgrowths of the major embryonic veins which develop in a cranio-caudalward direction from the jugular to the pelvic region. As a result of differences in growth rates of adjacent anatomical structures this series of early lymphatic primordia becomes subdivided into 4 singular primordia and 12 groups of primordia. After the constituents of each group of early primordia have fused, 16 isolated lymphatic plexuses (sacs) are formed of which 14 are in bilaterally symmetric and 2 are in a median line position: i.e. bilaterally: (1) the jugulo-axillary lymph sac situated lateral to the anterior cardinal vein and dorsal to the primitive ulnar vein and its major branch, the external mammary vein, (2) the paratracheal lymph plexus situated medial to the anterior cardinal vein, (3) the internal thoracic lymph plexus situated lateral to the thoracic part of the posterior cardinal vein, (4) the thoracic ducts situated medial to the thoracic part of the posterior cardinal vein, (5) the lumbar lymph plexus situated dorso-lateral to the abdominal part of the posterior cardinal vein, (6) the subcardinal lymph plexus and (7) the iliac lymph plexus situated ventro-lateral to the abdominal part of the posterior cardinal vein; and in the median line: (8) the subtracheal lymph plexus situated at the confluence of the pulmonary veins and (9) the mesenteric lymph plexus situated near the confluence of the splenic and the superior mesenteric veins. Except for some openings at the jugulo-subclavian confluence all connections with the veins disappear. From the primordia extensions grow out centrifugally. They invade the surrounding tissues and, in part, fuse with similar sprouts of adjacent primordia. In this way a continuous system of lymph truncs is formed that opens into the venous system at the jugulo-subclavian confluence.     

Development of the ascending lumbar and azygos veins in human embryogenesis

The ascending lumbar and azygos veins make a single magistral, but with different topography in the abdominal and thoracic cavities. The former runs more dorsolateral than the sympathetic trunk, and the latter--more ventromedial. These vessels are of different origin in human embryogenesis. The ascending lumbar vein develops from supracardinal veins of the abdominal cavity, that unite the dorsomedial tributaries of the postcardinal vein. The supramesonephral (thoracic) part of the latter makes the azygos vein trunk. Its beginning in the form of a plexus is determined by anastomosing supracardinal, postcardinal and mesocardinal veins. The mesocardinal vein serves as a longitudinal anastomosis for veins, connecting medial tributaries of the postcardinal vein. Differential peculiarities of its basin over the whole length and topographic peculiarities of the ascending lumbar and azygos veins depend on growth specificity of kidneys and adrenals, as well as on other organs in human embryogenesis.     

Growth of the jugular lymph sacs and establishment of the topography of the cervical portion of the thoracic duct during early human ontogenesis

In 196 human embryos, prefetuses, fetuses and newborns, by means of a complex of morphological methods, development of the jugular lymphatic sacs and the process of settling of the thoracic duct cervical part topography have been studied. The jugular lymphatic sac anlages take place on the 6th week of the development. From the lymphatic cleft, situating in the mesenchyme near the anterior cardinal veins, multichambered cavities laid with endotheliocytes are forming,--the jugular lymphatic sacs. Connection of the initially close lymphatic sacs with the venous system takes place secondarily by the end of the embryonic period of development. In the area of the sac ostia a valve is formed, that makes morphological premises for unidirected lymph flow into the venous system. The lymph nodes developing at the place of the reducing jugular lymphatic sacs, ensure formation: from the left jugular lymphatic sac--the cervical part of the thoracic duct, from the right jugular lymphatic sac--the right lymphatic duct and the jugular and the subclavicular lymphatic trunks. Variability in the form and topography of these structures are determined both by the form and construction of the jugular lymphatic sacs and by developmental peculiarities of the lymph nodes at their place. The process of settling of the thoracic duct cervical part topography depends on age changes of its size and form, as well as on development of structures situating nearby, and by the time of birth it is not completed.     

The anlage of the duodenal lymphatic bed: morphogenetic prerequisites, structure and importance

The anlage of the duodenal lymphatic bed takes place on the 3d month of the human intrauterine life. In the intestinal villi there are chyle sinuses, that fuse into presumptive lymphatic vessels, having capillary structure, when they get out of the villi. Intraorganic vessels turn into extraorganic ones, they flow into the pancreatoduodenal lymphatic vessels. In their lumens stromal anlage of the lymphatic nodes are formed as a result of invagination of the blood vessels. Development of the lymphatic bed in the duodenum preceded with formation of intestinal villi (this contributes to absorption of the intestinal content) and deformity of the superior mesenteric vein (this probably makes difficult the organ's drainage). The situation is solved owing to the lymphatic bed anlage. It is, evidently, formed by means of switching off a part of embryonal veins from the blood stream.     

Roentgenologic investigation of collateral lymphatic pathways after ligation of the thoracic duct

In 80 Wistar rats by means of electroroentgenolymphography lymphatic pathways and thoracic duct have been studied, normal and after ligation of the latter in 1-3 days, 1 and 2-3 months. Contrasting of the thoracic duct in the control animals reveals its additional ducts, that run in parallel to the main collector and they get into it after a certain distance, as well as different time phases of filling the duct are noted. When the thoracic duct is ligated, in 1-3 days dilatation of the ductal cistern, contrasting of lymphatic vessels and nodes in other regions are observed. In 1 month of the experiment the thoracic duct cistern is poorly expressed in comparison with the early time. The contrast substance continues to get into the group of the lymph nodes in other regions. A network of anastomoses of lymphatic vessels is formed in the area of ligation. In 2-3 months, when the contrast substance continues to get retrogradely into other groups and regions of the lymph nodes, final restoration of the lymph-flow takes place at the expense of formation of collateral pathways.     

Development of the thoracic duct in the prenatal period of human ontogeny

In 40 series of histological sections performed in human embryos and prefetuses from 4 up to 20 weeks of development, as well as in 20 corpses of fetuses and stillborns, it has been stated that the anlage of the thoracic duct appear in 6-7-week-old fetuses as lymphatic clefts surrounded with mesenchymal cells that are situated near large veins in the areas of the most active morphogenesis. Connecting with each other, the clefts form the jugular and retroperitoneal lymph sacs and a well branching network of canals. From the latter, on the 7th-8th week of development a plexus of lymph vessels appear, and later on (on the 8th-9th week)--bilaterally situating trunks of the thoracic duct. Further development of the thoracic duct is connected with the lymph nodes formation, their germs appear on the 9th-10th week along the course of the left trunk, as well as along the ductal branches and anastomoses. The formation of the lymph nodes results in reduction of some trunks and plexuses of the thoracic duct. Owing to this, its form in 14-15-week-old prefetuses resembles the one in newborns. Disturbances in the formation processes of the lymph nodes along the course of the reducing ductal areas, as well as their formation along the course of its main trunk can result in various structural variants of the thoracic duct in children and grown-up persons. Histogenesis of the thoracic duct wall and formation of the lymph nodes are not completed by birth.     

Length of the spinal dural sac, sex differences and correlation with the length of the spinal cord and vertebral column in adults

In 94 corpses (59 male and 35 female) of mature persons the length of the spinal dura mater sac has been studied. The average length of the sac is 621 +/- 3 mm. In men its average length is 636 +/- 4 mm, it makes 40 mm more in length than that in women (596 +/- 4 mm). The length of various parts in the dura mater sac is not the same: the cervical part makes 23% of the whole length, the thoracic--47%, the lumbar--23%, the sacral--7%. In men the cervical part of the sac in average is 6 mm longer than the lumbar part, and in women--quite the reverse, it is 7 mm shorter than the lumbar part. The sacral part of the sac in women is 3 mm longer that that in men. The sex differences noted are statistically significant. It is stated that the length of the spinal cord, its dura mater and the vertebral column are related as 1:1.5:1.7, the length of their cervical parts--as 1:1.5:1.4. the thoracic--as 1:1.3:1.3, the lumbar--as 1:2.4:3, the sacrococcygeal--as 1:1.4:4.9, respectively. During ontogenesis the greatest increase in the dura mater sac takes place in the cervical part as compared to the spinal cord and the vertebral column; in the thoracic part the intensity of their growth is equal: in the lumbar and in the sacrococcygeal part the increase of the vertebral column is the greatest.     

Distribution of the vasoconstrictor and vasorelaxant effects of norbormide along the vascular tree of the rat

Norbormide is a vasoconstrictor of rat peripheral arteries and a relaxant in rat aorta. To characterise norbormide actions within the rat vascular tree we have investigated its effects on the contractile function of rings from several arteries and veins. A maximal norbormide concentration (50 microM) failed to contract thoracic aorta and carotid artery, whereas in pulmonary artery, abdominal aorta, iliac, caudal, and femoral arteries it induced a contractile effect that was respectively 4.8 +/- 0.6, 18.4 +/- 1.5, 39 +/- 5, 144 +/- 7, and 260 +/- 22% of that induced by 90 mM KCl. In pulmonary, carotid, and iliac arteries, and in thoracic and abdominal aorta, 50 microM norbormide inhibited KCl-induced responses. Norbormide (50 microM) contracted all veins investigated. The effect, expressed as % of KCl-induced contraction, was 121 +/- 25, 154 +/- 14.5, 154 +/- 18.2, 203 +/- 19, and 267 +/- 33 for pulmonary vein, thoracic and abdominal vena cava, iliac and jugular veins, respectively. In jugular vein, as previously shown in rat caudal artery, norbormide contraction was abolished in Ca2+-free medium, was unaffected by the Ca2+ channel blocker nifedipine, and was relaxed by SK&F 96365, a blocker of store-operated Ca2+ channels. In conclusion: i) rat veins represent the main target for contractile norbormide action; ii) in both artery and veins norbormide contractions are generally inversely related to the calibre of the vessel; iii) norbormide-induced contraction is mediated by the same mechanism/s in arteries and veins; iiii) in norbormide-contracted arteries the drug activates both contractile and relaxing mechanisms.     

Extra-organic lymphatic vessels and regional lymph nodes of the kidneys in dogs

An anatomical investigation of extraorganic lymphatic vessels and regional renal lymph nodes has been performed in 70 dogs. The regional lymph nodes in the right kidney are stated to be quantitatively constant, as well as cranial and caudal lateroaortal lymph nodes in the left kidney in regard to the middle left lateroaortal nodes, that get lymph from the left kidney parenchyma. One middle left lateroaortal lymph node is found in 47 animals examined, two lymph nodes--in 17 animals. In 6 cases a lymphatic vessel, that gets lymph from the renal parenchyma and independently runs into the cistern of the thoracic duct is found for the first time. The variant revealed is an exception from the rule known in lymphology: lymph in its way from periphery to the central collector runs, at least, through one lymph node.     

Live imaging of lymphatic development in the zebrafish

The lymphatic system has become the subject of great interest in recent years because of its important role in normal and pathological processes. Progress in understanding the origins and early development of this system, however, has been hampered by difficulties in observing lymphatic cells in vivo and in performing defined genetic and experimental manipulation of the lymphatic system in currently available model organisms. Here, we show that the optically clear developing zebrafish provides a useful model for imaging and studying lymphatic development, with a lymphatic system that shares many of the morphological, molecular and functional characteristics of the lymphatic vessels found in other vertebrates. Using two-photon time-lapse imaging of transgenic zebrafish, we trace the migration and lineage of individual cells incorporating into the lymphatic endothelium. Our results show lymphatic endothelial cells of the thoracic duct arise from primitive veins through a novel and unexpected pathway.     

Lymphatic bed of layers of the abdominal wall in the human inguinal area]

Lymphatic bed in the layers of the inguinal area was studied in connection with age in 70 human corpses. Polychromic injection of arteries, veins and lymphatic bed, staining of preparations after van Gieson, Weigert, with hematoxylin-eosin and morphometry were the methods applied. It was stated that lymphatic capillaries penetrate through all the layers forming the abdominal wall of the human inguinal area; they arrange interconnected networks in dermis, in external and internal oblique and transversal muscles and in their aponeuroses, as well as in fasciae and in the peritoneum. The lymphatic bed in question changes during ontogenesis. Age transformations of the lymphatic capillaries are in connection with functional loading on the anterior abdominal wall. Intraorganic connections existing between the lymphatic vessels of the anterior abdominal wall and the organs of the small pelvis (urinary bladder, uterus, rectum, etc.) are revealed, they are of a rather great interest for physicians.     

Applied aspects of anatomy of the lumbar lymph nodes and their vessels

Using anatomical and roentgenoanatomical methods in 132 corpses of persons (from newborns up to 83 years of age) the anatomy of the lumbar lymph nodes and their vessels has been studied. Their topography, skeletotopy , amount, dimensions and form have been determined. Afferent and deferent lymphatic vessels in various groups of the lumbar lymph nodes, collateral pathways of lymph outflow to by-pass the lumbar lymph nodes are described. Certain data on the types of the thoracic duct formation are presented.     

Dual origin of avian lymphatics

The earliest signs of the lymphatic vascular system are the lymph sacs, which develop adjacent to specific embryonic veins. It has been suggested that sprouts from the lymph sacs form the complete lymphatic vascular system. We have studied the origin of the jugular lymph sacs (JLS), the dermal lymphatics and the lymph hearts of avian embryos. In day 6.5 embryos, the JLS is an endothelial-lined sinusoidal structure. The lymphatic endothelial cells (LECs) stain (in the quail) positive for QH1 antibody and soybean agglutinin. As early as day 4, the anlagen of the JLS can be recognized by their Prox1 expression. Prox1 is found in the jugular section of the cardinal veins, and in scattered cells located in the dermatomes along the cranio-caudal axis and in the splanchnopleura. In the quail, such cells are positive for Prox1 and QH1. In the jugular region, the veins co-express the angiopoietin receptor Tie2. Quail-chick-chimera studies show that the peripheral parts of the JLS form by integration of cells from the paraxial mesoderm. Intra-venous application of DiI-conjugated acetylated low-density lipoprotein into day 4 embryos suggests a venous origin of the deep parts of the JLS. Superficial lymphatics are directly derived from the dermatomes, as shown by dermatome grafting. The lymph hearts in the lumbo-sacral region develop from a plexus of Prox1-positive lymphatic capillaries. Both LECs and muscle cells of the lymph hearts are of somitic origin. In sum, avian lymphatics are of dual origin. The deep parts of the lymph sacs are derived from adjacent veins, the superficial parts of the JLS and the dermal lymphatics from local lymphangioblasts.     

A clonal analysis of tergite development in Drosophila of ultraabdominal and paradoxical genotypes.

The developmental parameters of homeotic second abdominal anlage cells in flies with Ultraabdominal and paradoxical genotypes are compared with those of normal second abdominal anlage cells through the use of induced mitotic recombination to mark the clonal descendants of single anlage cells. Homeotic and normal second abdominal anlage cells show the same pattern of mitotic activity during development. The homeotic second abdominal anlage cells with Ultraabdominal genotype proliferate to the same extent as normal anlage cells during hemitergite formation. However, the proliferation of homeotic second abdominal anlage cells with paradoxical genotype is decreased due to the failure of some daughter cells either to divide or to differentiate normally. The number of anlage cells in a homeotic second abdominal histoblast with Ultraabdominal genotype is slightly smaller and more variable than that in a normal second abdominal histoblast. The number of anlage cells in a homeotic second abdominal histoblast with paradoxical genotype is much smaller and much more variable than that in a normal second abdominal histoblast. These results are discussed in relation to mechanisms governing cell determination. In addition, some aspects of pattern formation in incomplete homeotic second abdominal hemitergites are presented and discussed.     

Development of the vasculature of the pectoral fin in the Australian lungfish, Neoceratodus forsteri

The development of the vasculature of the pectoral fin in the Australian lungfish, Neoceratodus forsteri, was studied by the dye-injection method. Only a single primitive subclavian artery appears from the dorsal aorta for the fin anlage, and it passes laterally through the postaxial region of the structure. The venous channel draining into the posterior cardinal vein is located in the preaxial region medially. As development proceeds, the arteriovenous arrangement in the pectoral fin anlage changes as follows: 1) one artery and one venous plexus, 2) two arteries and one vein, 3) three arteries and one vein, 4) four arteries and one vein, 5) three arteries and two veins, and 6) two arteries (radial and ulnar) and three veins (radial, ulnar, and ulnar marginal). The fin anlage through embryonic first rotation has gradually changed its postaxial margin to face dorsally and its preaxial margin to face ventrally. The second rotation causes the original preaxial margin to become dorsal and the original postaxial margin to become ventral. As a result, the radial and ulnar arteries are observed in the dorsal and ventral regions, respectively, in the medial side of the fin instead of in the lateral side as seen in the previous stage.     

Mechanical characteristics of the canine thoracic duct: what are the driving forces of the lymph flow?

This study is designed to better understand the mode of lymph transport, particularly through the extrinsic pumping by external compression of the lymph vessel. The pressure-diameter relationship of lymphatic segments isolated from the canine thoracic duct was examined using a laser optical micrometer measurement system. Results revealed that the thoracic duct displayed a high extensibility or compliance in the physiological pressure range, yet became progressively less so with increasing internal pressure. The calculated incremental circumferential modulus of the thoracic duct under physiological pressure (range of 2 to 6 cm H2O) showed values ranging from 1.2 x 10(4) to 3.61 x 10(5) dyn/cm2. At a pressure of 35 cm H2O, the modulus reached a limiting value of approximately 6.0 x 10(6) dyn/cm2. In the physiological pressure range, the relative wall thickness (h/R0) of the canine thoracic duct was approximately 3.5%, which was much lower than that reported for canine arterial segments and similar in value to that of the canine jugular vein. In conclusion, the pressure-diameter curve of the canine thoracic duct was shown to resemble that of venous vessels. However, the circumferential elastic modulus of the thoracic duct wall was lower than the moduli of veins, proving that lymphatics are more compliant than veins. This suggests lymph flow in the thoracic duct may be better promoted by external compression of the lymphatic vessel.     

Adrenergic innervation of lymph nodes and the thoracic duct

By means of incubation of slices in 2% solution of glyoxylic acid distribution of adrenergic fibers in the rabbit lymph nodes and in the thoracic lymphatic duct has been studied. Adrenergic fibers get into parenchyma of the lymph nodes via two ways. The first--the perivascular, when the nervous fibers make a plexus and get into the node along the blood vessels, the second--diffuse nervous fibers get together with trabecules in between the lymphoid nodules. The distribution density of the adrenergic fibers is not the same in different groups of the lymph nodes. In the lumbar nodes it is the highest. In the lymph nodes of the cervical part the density of the sympathetic fibers is, as a rule, lower than in the lumbar, but higher than in the axillary nodes. The lowest density of th adrenergic fibers is in the mesenteric, superficial inguinal lymph nodes and in the lymph nodes, situating near the thoracic part of the aorta. In the lymphatic duct wall small amount of adrenergic fibers are revealed, they form a plexus, predominantly in the cranial part.     

Caractérisation des adénopathies médiastinales en TEP/TDM au 18F-FDG

The mediastinum is a complex anatomical region located at the junction of the cervical, thoracic and abdominal regions. It is an important lymphatic gateway that has an impact in many pathologies with nodal involvement and for which ¹⁸F-FDG PET/CT is a central examination. In this review article, we propose to recall the normal and pathological lymphatic drainage, mediastinum anatomy, the International Association for the Study of Lung Cancer (IASLC) lymph node classification and its implications in lung cancer. Then we will detail the morphological and metabolic characteristics, principal etiologies and the procedures to access mediastinal lymph nodes.     

Sound radiation in a cicada: the role of different structures

Sound radiation was studied in males of Tympanistalna gastrica St»l during a spontaneous song with the characteristics of the conspecific calling song, which was elicited as an after effect of brain stimulation. The song contains two different kinds of sound pulses: 1) loud clicks and 2) soft pulses, presenting different spectra.The timbals, abdomen, tympana, folded membranes and opercula were tested as potential radiators of the song. The experiments included: 1) probe microphone measurements of the spectra of loud clicks and soft pulses in several positions around the animal and close to the body surface; 2) measurements of the spectra before and after covering with vaseline different structures that might be relevant to the radiation of the song, and manipulations of the size and shape of the abdominal and thoracic portions of the tracheal air sac; 3) laser vibrometry measurements in different parts of the body, both during singing and external sound stimulation.The data obtained demonstrate that several structures contribute differently to the radiation of clicks and soft pulses: 1) The timbals are the main radiators at frequencies around the dominant spectral peak, 10–11 kHz in clicks and 12–13 kHz in soft pulses; 2) The tympana are important in radiation of frequencies below and above the timbal peak, especially during the generation of soft pulses; 3) The abdomen is more activated during the generation of clicks, and is more important in the radiation of low frequencies around 5 kHz.Manipulations of the body cavities showed that neither the thoracic nor the abdominal portions of the air sac are critical for the song tuning. The large abdominal cavity do not seem to work as a Helmholtz resonator. We found no evidence that resonances inside this cavity should play an important role in enhancing sound radiation in T. gastrica.