PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “LYMPHATIC VESSELS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Fine structure of conjunctival lymphatic vessel valves].

BACKGROUND: Lymphatic valves are due to ensure a zentripetal flow of lymph. The majority of the authors regard these valves as bicuspid structures with joint insertion points of the downstream localized free valvular edges. Because of that valvular structure a retrograde flow of lymph is impossible. Observations of our own however demonstrated retrograde flow of fluid under physiological conditions. In the following paper the structure of conjunctival lymphatic valves should be investigated or rather those structures, which were regarded as valves hitherto. Are there segmental connections, which allow retrograde flow of lymph? Is a regulation of lymph flow possible without self-acting valves? MATERIALS AND METHODS: In the conjunctiva of bovine post-mortem eyes (n = 100) segmental connections of lymphatic vessels with a diameter of less than 1 mm were opened specifically under control of slit lamp microscope after having undertaken an interstitial double contrast lymphography (solution of Berliner Blue/air). Some of these preparations (n = 20) could be investigated further on with the scanning electron microscope. That procedure allowed to make the patterns of flow and vessels structures in the beginnings of the lymphatic system observed with the slit lamp microscope congruent with those structures shown by the scanning electron microscope. RESULTS: The following segmental connections could be demonstrated: 1. Lymphatic vessels, which flow like a pipe into the wall of another segment. 2. Laterally arranged oval connections with valve resembling an aperture. 3. Segments of lymphatic vessels arranged in a line, which flow into one another between two hump-shaped protrusions with bicuspid valvular structures. Also the existence of different connecting structures ("valves") in one segment ("gear segment") were observed. In bulbus-like segmental connections arranged one behind the other with two valvular leaflets it could be demonstrated by scanning electron microscopy, that the two leaflets were attached apart at the vessel wall. That divergence to the previous models of lymphatic valves means, that these valvular leaflets cannot work as self-acting valves and prevent retrograde flow. CONCLUSIONS: However according to the valveless model of Libau a directed regulation of flow is possible. Perhaps the valvular structures described above play an important part by the interaction between the endothelium of lymphatic vessels and the substances transported in the lymph. The variety of segmental connections, the network of vessels with different diameters, which seem to be connected by feed-back, demand a new way of looking at the initial lymph flow.

Animals↗
PubMed1982

The ultrastructural basis of lipid transport in the absorbing lymphatic vessel.

Absorbing lymphatic vessels of intestinal villi were studied by electron microscopy tridimensional reconstruction in order to follow the passage of lipid from the interstitium into the capillary lumen. The duodenum and ileum of kittens after milk feeding, fasting and lymphatic stasis were investigated. Lipids reach the lymphatic system by intraendothelial 8-14 micrometers long channels, which are directed from the apical to the basal portion of the lacteals. Endothelial junctions were always intact, indicating that these complexes were not involved in the transport of large size molecules.

Animals↗
PubMed2007

Connexin26 expression is associated with lymphatic vessel invasion and poor prognosis in human breast cancer.

PURPOSE: Cx26, which is a constituent of the connexin family, has recently been shown to promote metastasis through enhancing the vascular invasion in mouse melanoma cells. In this study, we have investigated whether or not Cx26 expression is associated with vascular invasion and recurrences in human breast cancers. EXPERIMENTAL DESIGN: Cx26 expression was studied in 152 invasive breast cancers by immunohistochemistry. In order to investigate the blood vessel invasion and lymphatic vessel invasion with precision, immunohistochemical staining of blood vessels and lymphatic vessels was carried out using anti-CD34 and anti-D2-40 antibodies, respectively. RESULTS: Cx26 was positive in 51.3% (78/152) of the breast tumors. A statistically significant association was observed between Cx26 expression and large tumor size (P = 0.013) or high histological grade (P = 0.043). Frequency of blood vessel invasion was higher in Cx26-positive tumors (5.1%, 4/78) than in Cx26-negative tumors (1.4%, 1/74) though not statistically significant (P = 0.210). Lymphatic vessel invasion was significantly (P = 0.001) more frequent in Cx26-positive tumors (39.7%) than in Cx26-negative tumors (14.9%). Patients with Cx26-positive tumors showed a significantly (P < 0.001) poorer prognosis than those with Cx26-negative tumors. Multivariate analysis showed that Cx26 (P < 0.05) expression was an independent prognostic factor. CONCLUSIONS: Cx26 expression is associated with lymphatic vessel invasion, large tumor size, high histological grade, and poor prognosis in human breast cancers. Cx26 seems to enhance the metastasis probably through promoting the lymphatic vessel invasion. Cx26 might be clinically useful as a new prognostic factor.

Antibodies, Monoclonal↗
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↗
PubMed2005

Development of lymphatic vessels: tumour lymphangiogenesis and lymphatic invasion.

In human solid cancer, the lymph node status is the most important prognostic indicator for the clinical outcome of patients. Follow-up data has shown that about 80% of metastasis follows an orderly pattern of progression via the lymphatic network while about 20% systemic metastasis occurs, bypassing the lymphatic system. Over the past few years, advances have been made in understanding the cellular and molecular aspects of physiological lymphangiogenesis and tumour-induced lymphangiogenesis, and the majority of studies point out to a positive correlation between tumour-induced lymphangiogenesis and lymphatic metastasis. However, the impact of intra- and peritumoural lymphatics on the tumour biology and the first steps of lymphatic metastasis, i.e. the invasion of tumour cells into the lymphatic vessels, are not well understood. We will give an outline of i. the physiological process of lymphangiogenesis, ii. tumour-induced lymphangiogenesis and lymphatic metastasis, iii. lymphatic invasion and the common pathways of tumour-lymphangiogenesis and lymphatic invasion. The growing interest in this topic has brought up a number of new molecular players in the field, which may provide the basis for a rational therapy against the process of lymphatic dissemination of tumour cells.

Animals↗
PubMed1983

Effects of arachidonic acid and its cyclo-oxygenase and lipoxygenase products on lymphatic vessel contractility in vitro.

Lymphatic vessels exhibit rhythmical contractility in vivo and in vitro and this activity appears to regulate lymph flow. A technique for measuring the circular muscle contractions of isolated bovine mesenteric lymphatic vessel segments has been devised and utilized to study the pharmacological properties of these vessels. Non-contracting lymphatic vessels can be induced to contract rhythmically with a variety of mediators, the most potent being a stable PGH2 analogue (compound U46619), and the leukotrienes B4, C4 and D4 (threshold concentrations in the nanomolar range). Prostaglandin F2 alpha, noradrenaline, serotonin and histamine also elicited rhythmical activity but much higher concentrations were required. PGE2 and PGE1 were potent inhibitors of spontaneous contractions or those induced with U46619. In keeping with the diverse pharmacological effects of the metabolites of arachidonic acid, the addition of arachidonate to an isolated lymphatic vessel generated both stimulatory and inhibitory activities. It is concluded that arachidonic acid products (produced in the lymphatic vessel or entering the vessel in lymph draining the tissues) regulate lymph flow through their effects on lymphatic smooth muscle.

Alprostadil↗
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↗
PubMed2006

Distribution of lymphatic vessels in mouse thymus: immunofluorescence analysis.

Thymic blood and lymphatic vessels in humans and laboratory animals have been investigated in morphological studies. However, occasionally a clear distinction between blood vessels and lymphatic vessels cannot be made from morphological characteristics of the vasculature. To visualize thymic lymphatics in normal adult BALB/c mice, we used antibodies against specific markers of lymphatic endothelial cells. Expression of vascular endothelial growth factor receptor-3 (VEGFR-3) was detected throughout the thymus, i.e., the capsule, cortex, and medulla. Most thymic lymphatics were present in capillaries of ~20 mum in caliber. The plexuses of lymphatic capillaries were occasionally detectable. Lymphatic vessels were frequently adjacent to CD31-positive blood vessels, and some lymphatic vessels were seen in the immediate vicinity of or within the perivascular spaces around postcapillary venules. The identity of VEGFR-3-positive vessels as lymphatics was further confirmed by staining with additional markers: LYVE-1, Prox-1, neuropilin-2, and secondary lymphoid tissue chemokine (SLC). The distributions of LYVE-1 were similar to those of VEGFR-3. Most lymphatic vessels were also identified by Prox-1. Neuropilin-2 was restricted to lymphatic vessels in the thymus. The most abundant expression of SLC in the thymus was in medullar epithelial cells; SLC was also expressed in lymphatic vessels and blood vessels. Thus, lymphatic endothelium in mouse thymus was characterized by positive staining with antibodies to VEGFR-3, LYVE-1, Prox-1, neuropilin-2, or SLC, but not with an antibody to CD31. Our results suggest the presence of lymphatic capillary networks throughout the thymus.

Animals↗
PubMed1998

[Laryngeal extra-organic lymphatic vessels in postnatal ontogenesis].

Extralaryngeal lymphatic vessels were studied in normal conditions in 44 cadaveric preparations obtained from people who died aged from 17 up to 91 using polychrome interstitial injection of Herot mass into laryngeal mucosa with the following anatomic preparation of extraorganic lymphatic vessels of larynx and lymphatic nodes. Average number of extralaryngeal lymphatic vessels was found to be minimal in senile age. Their content was asymmetric from right and from left in 70.5% cases, in 30.6% of which there was a predominance of left-side asymmetry. In women the number of extraorganic lymphatic vessels tended to grow. Mean number of extraorganic lymphatic vessels changes differently in men and women. In men significant decline in extralaryngeal lymphatic vessels occur from teenage up to senile period, in women vessel number tend to grow from the second period of maturity while average number of extraorganic lymphatic vessels significantly reduces.

Adolescent↗
PubMed2006

A pathological analysis of lymphatic vessels in early renal allograft.

Lymphatic vessels are an essential part of the immunological response. Nevertheless, little is known about the pathology of renal transplant rejection. In part the reason may be not distinguishing peritubular capillaries from lymphatic vessels by periodic acid-Schiff (PAS) staining. This study examined the morphology of lymphatic vessels in early renal allografts using double staining with PAS and podoplanin. The 41 cases were divided into four categories: (I) acute antibody-mediated rejection, (II) acute cellular rejection, (III) peritubular capillaritis only, and (IV) controls. I through III had the evidence of peritubular capillaritis exceeding grade 1 on a biopsy obtained an average of 17.3 +/- 5.5 days after kidney transplantation. In addition, each lymphatic vessel density (LVD) and nodular lesion of lymphocytes (NL) were quantified as the number of each podoplanin-positive vascular profiles and NL per unit area of cortex measured Lumina Vision (Mitani). The average of the LVD was 73.0, 35.1, 37.1, and 8.1 per 10 mm2 for groups I to IV and the average of NL was 2.8, 5.5, 1.3, 0.9, respectively. There was a significant correlation between LVD and NL. NL showed a strong relation to the accumulation of lymphocytes in lymphatic vessels (AL); 22% of the AL scores were greater than the peritubular capillaritis grade. We found lymphatic vessels to be strongly associated with any kind of inflammatory process that occurred unexpectedly soon after kidney transplantation. In addition, to avoid misdiagnosis of peritubular capillaritis, NL in early renal allograft must especially be excluded.

Adult↗
PubMed2003

Vascular endothelial growth factor C is required for sprouting of the first lymphatic vessels from embryonic veins.

Lymphatic vessels are essential for immune surveillance, tissue fluid homeostasis and fat absorption. Defects in lymphatic vessel formation or function cause lymphedema. Here we show that the vascular endothelial growth factor C (VEGF-C) is required for the initial steps in lymphatic development. In Vegfc-/- mice, endothelial cells commit to the lymphatic lineage but do not sprout to form lymph vessels. Sprouting was rescued by VEGF-C and VEGF-D but not by VEGF, indicating VEGF receptor 3 specificity. The lack of lymphatic vessels resulted in prenatal death due to fluid accumulation in tissues, and Vegfc+/- mice developed cutaneous lymphatic hypoplasia and lymphedema. Our results indicate that VEGF-C is the paracrine factor essential for lymphangiogenesis, and show that both Vegfc alleles are required for normal lymphatic development.

Animals↗