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At least 19 recordsLinked to original sources
PubMed1996

A study of the three-dimensional organization of the human diaphragmatic lymphatic lacunae and lymphatic drainage units.

The peritoneal stomata, lymphatic drainage units and subperitoneal terminal lymphatics, called lymphatic lacunae, form a specialized drainage system in the diaphragm, by which absorption of fluid in bulk, particles and cells is carried out in the peritoneal cavity. The aim of this study is to elucidate the three-dimensional organization and function of the subperitoneal lymphatic lacunae and lymphatic drainage units by using lymphatic casts in the scanning electron microscope (SEM), ODO (OsO4-DMSO-OsO4) freeze fracture, conventional SEM and the transmission electron microscope (TEM). The subperitoneal lymphatic lacuna is unique for its large size and its multiple morphology and can be recognized by its broad, flattened enlargement and the blind-ends of lymphatic vessels, from which extend numerous main lymphatic vessels and side branches. These lymphatic vessels communicate with each other and form a rich lymphatic plexus under the diaphragmatic peritoneum. Two layers of lymphatic networks, i.e. the subperitoneal plexus and the deeper plexus are found in the muscular portion. Only one layer is present in the tendinous portion of the human diaphragm. The lymphatic plexus is denser in the tendinous portion than that in the muscular portion. The lymphatic lacunae occur exclusively in the muscular portion of the human diaphragm. The lumina of lymphatic lacunae are separated from the peritoneal cavity by a barrier consisting of cuboidal mesothelial cells, endothelial cells of the lymphatic lacunae and intervening connective tissue forming a lymphatic drainage unit. All these three components of the lymphatic drainage unit abut upon each other, but are not linked by specialized junctions. The cuboidal mesothelial cells frequently extend valve-like cytoplasmic processes that bridge the subperitoneal channel and make give it a tortuous course. The fibrous layer of the connective tissue is arranged in fiber bundles and gives a three-dimensional network forming the floor of the peritoneal stomata and the roof of the lymphatic lacunae. Via the fibrous network, the cuboidal mesothelial cells and the endothelial cells of the lacunae come into close contact with each other and form short subperitoneal channels which connect the peritoneal cavity with the subperitoneal lymphatic lacunae. The lymphatic drainage units may regulate the material absorption of the peritoneal stomata from the peritoneal cavity. It is suggested that the peritoneal stomata together with the subperitoneal channels, lymphatic drainage units and lymphatic lacunae comprise an important diaphragmatic lymphatic drainage system which plays an important role in the absorption of materials from the peritoneal cavity.

Diaphragm↗
PubMed1997

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↗
PubMed1996

Distribution of lymphatics in human palatine tonsils: a study by enzyme-histochemistry and scanning electron microscopy of lymphatic corrosion casts.

The distribution of lymphatics in human palatine tonsils was studied by enzyme-histochemistry for 5'-nucleotidase (5'-Nase) and scanning electron microscopy (SEM) of lymphatic corrosion casts. The palatine tonsils were found to possess lymphatics in the parafollicular area (i.e., interfollicular, interfolliculo-septal, and folliculo-septal area), in the connective tissue septa, and in the capsules, but not in the subepithelial area between the follicles and the follicle-associated epithelia or within the follicles. The tubular lymphatics originated some 200-300 microns below the epithelium and formed a three-dimensional network in the parafollicular area. Some lymphatics around the lower part of the follicle were flat, wide, and irregular in shape, and thus appeared to be lymphatic sinuses, referred to as perifollicular lymphatic sinuses. The lymphatics in the parafollicular area drained into the septal lymphatics, which ran rather straight in the connective tissue septa. The septal lymphatics finally gathered into the broader capsular lymphatics. Most of the septal and capsular lymphatics were endowed with valves. Our results indicate that lymphocytes and fluid from the follicles and the subepithelial region enter the perifollicular lymphatic sinuses and/or the interfollicular lymphatics, pass through the interfolliculo- and folliculo-septal lymphatics, and finally enter the septal and capsular lymphatics to leave the tonsil.

5'-Nucleotidase↗
PubMed2001

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↗
PubMed2001

Selective immunohistochemical staining of blood and lymphatic vessels reveals independent prognostic influence of blood and lymphatic vessel invasion in early-stage cervical cancer.

Lymphovascular space invasion was shown to play a key role in the progression of cervical cancer. Because of the absence of a specific marker for lymphatic vessels, earlier studies could not reliably distinguish between blood and lymphatic vessel invasion. By immunostaining for podoplanin, a novel marker for lymphatic endothelium, and for factor VIII-related antigen, we determined lymphatic and blood vessel invasion in tissue samples of 98 patients with cervical cancer pT1b treated by radical hysterectomy. Eleven (11.2%) specimens showed invasion of blood vessels, 20 (20.4%) showed invasion of lymphatic vessels, and 15 (15.3%) showed invasion of blood and lymphatic vessels. There was a strong association of lymphatic vessel invasion and lymph node involvement (P < 0.001). In univariate analysis, both blood and lymphatic vessel invasion failed to reach a statistically significant influence on overall survival, but a significant influence on disease-free survival was found (P = 0.0002 and P < 0.0001, respectively). In multivariate analysis of disease-free survival, only blood vessel invasion remained statistically significant (P = 0.0457). Lymphatic vessel invasion reached significance when lymph node status was excluded from the model (P = 0.0025). Both lymphatic vessel and blood vessel invasion occur frequently in early-stage cervical cancer. Determination of the vessel status may be of clinical importance because it signifies the risk of recurrent disease.

Adult↗
PubMed1999

The lymphatic vessels and the so-called "lymphatic stomata" of the diaphragm: a morphologic ultrastructural and three-dimensional study.

We studied the absorbing peripheral lymphatic vessel with the light microscope, the transmission electron microscope, the scanning electron microscope, and three-dimensional models of the diaphragm of several rodents and insectivores under normal and experimental conditions (lymphatic stasis and dehydration). To clarify the delicate and complex mechanism that permits drainage of the abdominal cavity contents into the lymphatic circulatory system, we introduced Polystyrene latex spherules, China ink, and Trypan blue into the abdominal cavities. After anatomical comparisons of the superficial and deep networks of absorbing peripheral lymphatic vessels at the tendinous and muscular portions of the diaphragm and after classification of lymphatic vessels into absorbing and conducting functions, we examined the stomata, which, owing to morphologic and topographic findings, we defined as stable structures. Furthermore, we observed that the stomata and submesothelial connective channel are fundamental elements that facilitate the flow of the corpuscular and liquid contents of the peritoneal cavity to the submesothelial absorbing lymphatic vessel wall. Also, we underlined that the genesis of the connective channel depends on the secondary cytoplasm extensions of two distinct adjacent endothelial cells, which, to facilitate the flow of the absorbed abdominal contents, completely coat this channel. Additionally, our observations illustrate that the secondary cytoplasm extensions do not engage in continuous relationships with the basal lamina of the mesothelium and with the margins of the stoma, and, hence, the hypothesis of "lymphatic stomata" as an expression of the anchoring of the borders of the open interendothelial junctions to the orifice margins of the stoma cannot be confirmed. Moreover, we describe the presence and formation of intraendothelial channels in the lymphatic endothelial wall. We affirm that this morphological entity is a dynamic unit, because its numerical density varies according to different physiological and experimental conditions to degrees of hydrostatic and colloidal osmotic pressure and, perhaps, also to the particular characteristics of the substances that the connective channel liberates into the endothelial wall of the lymphatic vessel. In conclusion, we affirm that the absorbing peripheral lymphatic vessels of the diaphragm, by way of intraendothelial channel formations, membrane diffusion, and the vesicular path of the endothelial cells, constitute the fundamental draining elements for the corpuscular and liquid contents of the abdominal cavity.

Absorption↗
PubMed1998

[Locally advanced prostate carcinoma (T2b-T4 N0) without and with clinical evidence of local progression (Tx N+) with lymphatic metastasis. Is radiotherapy for pelvic lymphatic metastasis indicated or not?].

BACKGROUND: There is a greater controversy regarding the indication of radiotherapy of the pelvic lymphatics in patients with suspected lymph node metastases in locally advanced prostate cancer (T2b-4 N0) on the one hand and in patients with pathologically proven lymph node metastases in locoregional advanced prostate cancer (Tx pN+) on the other hand following definitive radiotherapy and radical prostatectomy. This paper investigates the possible indications for radiotherapy of the pelvic lymphatics in the light of data from the literature. PATIENTS AND METHODS: Because data from several retrospective studies concerning radiotherapy of the pelvic lymphatics indicated a better outcome, the RTOG conducted 2 prospective randomised studies (RTOG 75-06, 77-06) to address these questions. However, the results of these studies showed no better survival or cause specific survival for patients treated for the paraaortal or pelvic lymphatics and therefore, radiotherapy of the pelvic lymphatics was no more advocated. A reanalysis showed several problems of the study design and it was concluded that the studies couldn't prove the question of elective radiotherapy of the pelvic lymphatics. In RTOG 77-06 patients with T1b/T2 tumors were investigated. Therefore, there is no prospective study investigating the elective radiotherapy in patients with T3-tumors, who are at high risk of pelvic lymph node metastases. RESULTS: Today there is no indication for treating the paraaortal lymphatics in patients with locoregional advanced prostate cancer. Many radiotherapists perform the elective radiotherapy of pelvic lymphatics when the risk of metastases is above 15 to 20% because retrospective data indicate a better outcome. On the other hand, many others don't treat them because RTOG 75-06 and 77-06 didn't demonstrate a better outcome. Laparoscopic lymphadenectomy with low morbidity seems to be helpful as in pN0 patients radiotherapy is not necessary. Where performing laparoscopic pelvine lymphadenectomy is impossible the probability of the frequency of lymph node metastases can be estimated using the clinical tumor stage, the Gleason-score and the pretherapeutic PSA. In case of proven metastases (pN+) some retrospective data indicate that patients with micrometastasis could profit from aggressive treatment. In case of proven metastases and extirpation by lymphadenectomy it seems that patients with hormonal therapy and radiotherapy have a longer tumor-free interval. However, there are no data from randomized trials. CONCLUSIONS: Every radiotherapist has to make his own decision for radiotherapy of the pelvic lymphatics as there is no standard treatment. Two randomised studies are open and recruiting patients. These are one study of the ARO, investigating patients with histologically proven lymph node metastases and one study of the RTOG (RTOG 9413), investigating patients with an estimated risk of lymph node metastases > 15%. In case of radiotherapy of the pelvic lymphatics a dose of 45 Gy for suspected metastases and 50.4 Gy for proven metastases is recommended.

Carcinoma↗
PubMed1992

Structure of lymphatics in rat cecum with special reference to submucosal collecting lymphatics endowed with smooth muscle cells and valves. I. A scanning electron microscopic study.

The three-dimensional structure of lymphatic vessels in the rat cecum was studied by KOH-collagenase digestion/scanning electron microscopy (SEM), and corrosion casting/SEM. Abluminal surfaces of the lymphatic vessels show flat elliptical nuclear regions and flat cytoplasmic processes interdigitated with adjacent ones. The lymphatic capillaries closed by interdigitations of flat endothelial processes at their initial portion begin at the various levels of the mucosa. They descend and pass through the muscularis mucosa to connect with the lymphatic vessels in the submucosa. They form polygonal meshwork, the distances between intersections being about 0.2-0.5 mm. They also have valves, the distances between adjacent valves being about 0.1-0.6 mm. Most of the submucosal lymphatic vessels are surrounded by either periendothelial cells or typical smooth muscle cells. The polygonal meshworks made up of stellate periendothelial cells with many irregular processes embrace the initial segment of the collecting lymphatics. As they proceed proximally, the periendothelial cells become elongated and branch out by threes or fours, thus presenting the appearance of smooth muscle cells. These branches are connected side by side and run obliquely along the vessels, thus forming polygonal meshworks around the vessels. The more proximal collecting lymphatic vessels are surrounded by circularly oriented smooth muscle cells. Our results indicate that most of the lymphatic vessels in the submucosa are collecting ones and possess smooth muscle cells as well as valves. This suggests that the lymphatic vessels in the submucosa actively contract and propel the lymph towards the mesenteric lymphatic vessels.

Animals↗
PubMed1994

Three-dimensional structure of two different lymphatic spaces in rat testis, and the route of flow fluxes of their lymphatic fluids.

In addition to the collecting vessels, two initial lymphatic spaces were observed with light and electron microscopes. In the deep parenchyma, the peritubular lymphatic spaces surrounding the tubules were observed as polygonal piles after a corrosion casting to the testis. They were joined to the adjacent piles through fenestrae to form a loose spongiform structure. In the superficial parenchyma, the peritubular lymphatic spaces communicated to the subtunical lymphatic space on one side. The subtunical lymphatic spaces anastomosed to each other through small bypasses to form a rich network. Near the mediastinum, the peritubular lymphatic spaces bifurcated and narrowed on another side. Microradiography demonstrated two fluxes of the intratesticular lymphatic fluids; fast and slow flows. The fast flow was observed as a shaded line running into the subtunical lymphatic spaces immediately after injection of the contrast media. It remained 1 or 2 minutes and then disappeared. In contrast, the slow flux was observed as a spongiform shade shifting from the anteroposterial quadrant to the posterosuperior portion of the testis. Seven to 15 minutes were needed for the contrast media to reach near the mediastinum. Both lymphatic spaces are functionally discussed with relation to the two different fluxes of the lymphatic fluids.

Animals↗
PubMed1994

Cytochemical differentiation between blood and lymphatic endothelium: bovine blood and lymphatic large vessels and endothelial cells in culture.

Cytochemical differentiation between blood and lymphatic endothelium has been studied only in microvessels; 5'-nucleotidase (5'Nase) has been reported to be specific for lymphatic and alkaline phosphatase (ALPase) for blood endothelium. Adenylate and guanylate cyclase (AC and GC) have recently been proposed as lymphatic endothelial markers, but conflicting data exist. This study was designed to verify the presence of these enzymes in the endothelium of large vessels and to determine whether they are retained in endothelial cells (ECs) in culture. Segments of bovine mesenteric arteries, veins, and lymphatic collectors, and EC cultures obtained by collagenase treatment of the same vessels, were assayed for 5'Nase, ALPase, AC, and GC, and were observed by transmission electron microscopy. We found ALPase activity in blood and lymphatic vessels, and this was the only enzyme activity consistently retained under culture conditions. 5'Nase was found in lymphatic but not in blood endothelium, as previously reported for microvessels. AC and GC activity was found in blood but not in lymphatic endothelium. Hence, ALPase is not a useful marker to differentiate blood from lymphatic endothelium in large vessels, whereas 5'Nase is specific for lymphatic and AC and GC for blood endothelium. It is not clear why these enzyme activities are not expressed in culture.

5'-Nucleotidase↗
PubMed2000

[Immuno-histochemical identification of initial lymphatics: the contour and distribution pattern of initial lymphatics in the human foreskin of the penis].

PURPOSE: There has not been an established method to distinguish initial lymphatics from blood capillaries under the light microscopy. In this study, we examined the usefulness of the immuno-histochemical staining method using a monoclonal anti-desmoplakin antibody in identifying initial lymphatics under the light microscopy. The specificity of this reaction was confirmed by the immuno-electron microscopy. MATERIAL AND METHODS: The cryostat sections of the human foreskin were observed under light microscopy by indirect immunoperoxidase method with the anti-desmoplakin mouse monoclonal antibody, and compared with the hematoxylin and eosin sections. These cryostat sections were also observed under electron microscopy by pre-embedding immunoperoxidase method with the same antibody. RESULTS: Under the light microscopy, the initial lymphatics of the human foreskin were visualized by the method with anti-desmoplakin antibody. These lymphatics were mainly distributed in the dermal layer, on the other hand, rarely seen in dermal papillae. Being usually found in closed shape, the lumens of initial lymphatics were hardly recognized as initial lymphatics by the ordinary hematoxylin and eosin staining. Under the immuno-transmission electron microscopy, the peroxidase-desmoplakin antibody precipitations were located on the surface of the endothelial cells of the vasculature which lacked pericytes and basal lamina, and was composed of endothelial cells alone. By these features of the vascular structures, the vessel reacting with anti-desmoplakin antibody was identified as initial lymphatics. CONCLUSION: This study shows the reliability and specificity of the immuno-histochemical method by anti-desmoplakin antibody in identifying initial lymphatics under light microscopy, and this method will be useful in studying the fine distribution of lymphatic vessels in normal human tissue.

Animals↗
PubMed2003

Lymphatic microvessels in the rat remnant kidney model of renal fibrosis: aminopeptidase p and podoplanin are discriminatory markers for endothelial cells of blood and lymphatic vessels.

ABSTRACT. Rat remnant kidney is an established model of renal tubulointerstitial fibrosis and progression to end-stage renal failure. The morphologic lesions comprise nephron loss and regeneratory tubular hypertrophy, interstitial infiltration, predominately by macrophages, and progressive fibrosis. A critical role in this complex pathology was assigned to tubulointerstitial blood microvessels that regulate the supply of oxygen and nutrients of tubuli. Whereas some investigations reported a rarefaction of the vascular network in association with the degenerative cortical changes, others observed an increase in vascularization. Here these discrepant findings are addressed by reinvestigation of the vascularization of rat remnant kidneys by the use of two novel endothelial lineage specific, discriminatory markers, i.e., the membrane mucoprotein podoplanin with specificity for lymphatic endothelia, and the glycosyl-phosphatidylinositol (GPI)-anchored membrane enzyme aminopeptidase P that is recognized by a monoclonal antibody designated JG12 and that is specifically expressed by endothelial cells of blood vessels only. The results obtained confirm a regional rarefaction of aminopeptidase P-positive blood microvessels; they also establish major changes in the renal lymphatic vasculature. Massive proliferation of lymphatic vessels was observed in fibrotic tubulointerstitial regions, whereas in kidneys of sham-operated rats, only a few lymphatic vessels were found adjoined with arteries. The lymphatic vessels frequently contained mononuclear cells that were also encountered in the interstitial spaces and expressed relative large amounts of vascular endothelial growth factor-C mRNA by in situ hybridization. Collectively, these results indicate that a large proportion of the microvessels encountered in the cortex of remnant kidneys are of lymphatic origin and cannot be discriminated by common endothelial markers, such as CD34, that are expressed by both lymphatic and blood endothelia cells. As lymphatic endothelial cells secrete chemokines that attract dendritic cells, it is possible that the increase in lymphatic vascularization could enhance the immunologic surveillance of remnant kidneys.

Aminopeptidases↗
PubMed2002

Lymphatic metastasis in the absence of functional intratumor lymphatics.

Lymphatic metastasis contributes to mortality from solid tumors. Whether metastasizing cancer cells reach lymph nodes via intratumor lymphatic vessels is unknown. Here, we examine functional lymphatics associated with mouse tumors expressing normal or elevated levels of vascular endothelial growth factor-C (VEGF-C), a molecule that stimulates lymphangiogenesis. Although VEGF-C overexpression increased lymphatic surface area in the tumor margin and lymphatic metastasis, these tumors contained no functional lymphatics, as assessed by four independent functional assays and immunohistochemical staining. These findings suggest that the functional lymphatics in the tumor margin alone are sufficient for lymphatic metastasis and should be targeted therapeutically.

Adenocarcinoma↗
PubMed1999

Angiosarcomas express mixed endothelial phenotypes of blood and lymphatic capillaries: podoplanin as a specific marker for lymphatic endothelium.

Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposi's sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposi's sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposi's sarcomas expressed the lymphatic marker podoplanin.

Antigens, CD34↗
PubMed1989

Morphology of lymphatics of the mammalian heart with special reference to the architecture and distribution of the subepicardial lymphatic system.

The subepicardial lymphatic system in the rat and dog heart has been investigated by means of scanning electron microscopy. Following application of hydrogen peroxide, the epicardium was removed with a forceps under a dissecting microscope. The subepicardial region contained a well-developed lymphatic system which consisted of the main lymphatic trunks and lymphatic capillaries. The lymphatic trunks of large diameters ran from the apex of the heart to its base. The subepicardial lymphatic capillaries were ramified and anastomosed with each other to form a relatively dense network which extended over the entire surface of both ventricles. These networks joined the main lymphatic trunks. Further, some similar networks were connected with the underlying myocardial lymphatic capillaries.

Animals↗
PubMed1998

Lymphatic drainage of the cerebrospinal fluid from monkey spinal meninges with special reference to the distribution of the epidural lymphatics.

The structural organization of the epidural lymphatics and lymphatic drainage of the cerebrospinal fluid from spinal meninges was studied in Japanese monkeys (Macaca fuscata) by an enzyme-histochemical method. The spinal meninges were examined at various intervals from 1 to 48 h, as well as at 30 days, following an injection of ultrafine carbon particles into the subarachnoidal space (cisterna magna). Lymphatics were differentiated from blood capillaries by the 5'-nucleotidase (5'-Nase)-alkaline phosphatase (ALPase) double staining method (KATO et al. 1991, 1993) both in the whole-mount preparations and tissue sections. Carbon-filled collecting lymphatics and lymph nodes constantly appeared in the cervical and thoracic regions but only rarely in the lumbo-sacral region after carbon injection. Networks of 5'-Nase-positive lymphatics in the epidural connective tissues were seen in a large area on the dorsal surface around each spinal nerve root in the cervical and upper thoracic regions, especially at a level corresponding to the brachial plexus (C5-Th1). Carbon particles were often found within the 5'-Nase-positive lymphatics. In the lower thoracic and lumbo-sacral regions, on the other hand, the epidural lymphatic network covered only a small area around each spinal nerve root. These findings suggest that the epidural lymphatics are well developed on the dorsal side of the lower cervical spinal dura mater and may function as an absorptive pathway for the cerebrospinal fluid from the subarachnoidal space.

Animals↗
PubMed2000

Anatomic distribution of intraprostatic lymphatics: implications for the lymphatic spread of prostate cancer-a preliminary study.

BACKGROUND: Although prostate cancer metastasizes primarily into the lymphatic system, the anatomic distribution of intraprostatic lymphatics has not been elucidated. The aim of this study was to clarify the distribution of lymphatics in the human prostate by immunohistochemical techniques, using an anti-desmoplakin antibody. METHODS: Whole-mount cryostatic sections were serially cut from the noncarcinomatous prostates of adult men with bladder carcinoma who underwent cystoprostatectomy. Each section was stained either with a monoclonal antibody specific for desmoplakin or with hematoxylin and eosin. RESULTS: Lymphatics were detected in all components of the prostate. In the glandular prostate, lymphatics were distributed evenly in the peripheral, transitional, and central zones. The lymphatic density was significantly high in the midbase region surrounding ejaculatory ducts. CONCLUSIONS: These results may indicate the importance of the midbase region as a route of lymphatic spread of prostate cancer.

Aged↗
PubMed2000

Ultrastructural and three dimensional aspects of the lymphatic vessels of the absorbing peripheral lymphatic apparatus in Peyer's patches of the rabbit.

We studied the absorbing lymphatic peripheral vessels of the Peyer's patches of the small and large intestine of the rabbit by means of light microscopy after injection of Neoprene latex and transmission electron microscopy in order to highlight their topographical distributions to blood vessels as well as the morphologic mechanism of transendothelial passage of the lymphocytes to the lymph. The distribution of absorbing lymphatic vessels originates from the lacteal vessels and the subepithelial mucosal lymphatic network, which continue without interruptions and dilations into the vessels of the interfollicular area which are woven into basket-like networks entwining the medio-basal portion of each lymphoid follicle. The interfollicular area vessels then drain into the large vessels of the tunica submucosa, which in turn drain into the valved precollector vessels of the subserosa by way of intramuscular vessels. TEM revealed the absorbing lymphatic vessels to have a continuous endothelial wall without open junctions, fenestrations, and continuous basal lamina. We observed many lymphocytes wedged in the lymphatic endothelial wall. This underlines the different phases of their migration from the lymphoid tissue in the lumen of the lymphatic vessel. Results of ultrathin serial sections and three dimensional reconstruction of lymphatic vessel segments with included lymphocyte showed the transendothelial passage of lymphocyte, through the "intraendothelial channels."

Animals↗