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At least 181 records · Page 10Linked to original sources
PubMed2000

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium: an attempt to reactivate the 5'-nucleotidase activity with Mg++ ion supply.

Enzyme-histochemical demonstration of lymphatic vessels in the golden hamster periodontium was performed on cryostat sections using the 5'-nucleotidase (5'-Nase) staining method by light microscopy and backscattered electron imaging of scanning electron microscopy. The inhibition of the 5'-Nase activity by decalcification was cancelled by the Mg++ ion supply. The reaction products of 5'-Nase activity were produced on the lymphatic endothelial cells and the tubular structures of lymphatic vessels were seen as highlights by backscattered electron imaging. The invasion of 5'-Nase-positive lymphatic vessels into the alveolar bone from the periodontium was found in the present study.

5'-Nucleotidase↗
PubMed2004

Expression of inducible nitric oxide synthase in cultured smooth muscle cells from rat mesenteric lymphatic vessels.

OBJECTIVE: The objective was to devise a method for establishing cultures of rat mesenteric lymphatic vessel smooth muscle cells (LSMC) and to investigate if inducible nitric oxide synthase (iNOS) expression could be activated in LSMC treated with bacterial lipopolysaccharide (LPS). METHODS: LSMC were successfully grown from explanted rat lymphatic microvessels and maintained by subculture. Treatment of LSMC for 24 h with LPS (1-100 microg/mL) activated iNOS protein induction, associated with (1) assay of increased nitrite concentrations in the medium representing cellular nitric oxide synthesis, and (2) demonstration of iNOS in cell extracts by Western blotting. RESULTS: The protein synthesis inhibitor cycloheximide (10 microM) blocked both LPS-induced nitrite formation and iNOS protein expression in LSMC. 1400 W (1 microM), a selective iNOS inhibitor, prevented LPS-induced nitrite formation but not iNOS expression. As well as induction of iNOS by LPS, "constitutive" iNOS was present in some cultures, producing nitrite in amounts that were also subsequently reduced after cell treatment with 1400 W. CONCLUSION: Rat mesenteric LSMC produce nitrite and express iNOS in response to bacterial LPS. Cultured LSMC may provide a useful model for studying mechanisms of iNOS induction in relation to possible influences of iNOS upon lymphatic vessel function.

2-Propanol↗
PubMed2005

[Effect of new synthetic anxiolytic selank on gastric wall blood flow and mesenteryc lymphatic vessels contractility in anesthetized rats].

The influence of a new heptapeptide Selank on microcirculation in anesthetized white rats was investigated. Selank (Thr-Lys-Pro-Arg-Pro-Gly-Pro) is a new synthetic anxiolytic which exerts obvious antiulcerogenic action and promotes healing of experimental ulcers. Action of the peptide on gastric blood flow in the stomach by using the method ofhydrogenic clearance and Selank action on mesenteric lymphatic contractility by microscopical observation in situ, were studied. Selank fail to influence basal gastric blood flow but it can normalize blood flow reduced by indomethacin. The study of dose-depended of Selank effect on lymphatic vessels contractility showed that its low concentration (10(-12)--10(-14) M) enhanced amplitude and increase frequency of lymphatic vessel contractions which indicates an enhancement of lymphatic flow. The high doses of peptide (10(-6)--10(-10) M) also augmented the contraction amplitude but decreased its frequency. The maintenance of adequate blood flow and lymphatic vessel contractility can be one of the mechanisms of the Selank antiulcerogenic properties.

Animals↗
PubMedDate not supplied

On the presence and ultrastructure of valves in the lymphatic vessels of the canine ovary.

The origin and course of the intraovarian lymphatic vessels were examined by means of histologic studies of the gonads of pubertal female dogs. The small vessels that were present in the cortex near the follicles and corpora lutea flowed into an anastomotic network located at the margins of the medulla. Vessels of larger caliber were found to originate from the medulla and to reach the hilum by an approximately rectilinear pathway. In concordance with their previous findings in other species, the authors identified numerous semilunar valves in the lymphatic vessels of the cortex. Their ultrastructure is described.

Animals↗
PubMed2004

Mechanisms underlying the effect of E. coli endotoxin on contractile function of lymphatic vessels.

E. coli endotoxin decreased the amplitude and frequency of spontaneous phasic contractions in isolated bovine mesenteric lymphatic vessels. This substance in a concentration of 5 mg/liter blocked spontaneous contractions and reduced tonic tension of smooth muscle cells. The dilatory effect of endotoxin on lymphatic vessels was primarily realized via stimulation of synthesis of NO and prostacyclin by endotheliocytes.

Animals↗
PubMed1984

Lymphatic vessels in the uterine endometrium of virgin rats.

Uteri from four diestrous rats fixed by perfusion were examined histologically for the presence of lymphatic vessels in the endometrium, using 1 micron epoxy sections stained with toluidine blue. For each animal, multiple random sections were prepared from 3 tissue samples. In all sections, lymphatics were readily apparent in the myometrium, being identified by their irregular shape and contents of stained lymph proteins, which contrasted with the clear, empty blood vessels. While similar lymphatics were not seen in the endometrium of most tissue samples, one sample from each of three females revealed a small lymphatic vessel near the bases of the uterine glands, clearly in the endometrium. One of these was followed in serial alternating light and electron microscopic sections. The vessel maintained its relative position to the endometrial glands for a considerable distance, and also joined with two separate branches that appeared along its course. Ultrastructural observations, including a thin endothelium without a continuous basal lamina, the presence of anchoring filaments, and only mononuclear cells and cellular debris in the lumen, confirmed the vessel's identification as a lymphatic. The vessel's size was normally large enough to be followed by light microscopy; however, at some places along its course, the lumen narrowed to such a degree that it was only identifiable ultramicroscopically . These observations refute claims that there are no lymphatic vessels in rodent uterine endometrium, but indicate that they are small and sparsely distributed.

Animals↗
PubMed1978

[The lymphatic vessels of the stomach during phylogenesis and ontogenesis (author's transl)].

The stomach lymphatic channel of all classes of vertebrata representatives beginning from cartilagnous fish, was discovered. The lymphatic channel of cartilaginous and bony fish is presented only with lymphatic capillaries. The lymph is removed along peri- and paravascular lymphatic capillaries. The channel of the stomach of amphibians and reptiles is differentiated in lymphatic capillaries and lymphatic small trunks, while in birds and mammalia it is differentiated in lymphatie capillaries and lymphatic vessels. In human beings, macacus, dogs and cats the removing lymph pathways of the stomach wall in ontogeny undergo the following stages: 1) a lymphatic capillary, 2) a "wide" lymphatic capillary and 3) a lymphatic vessel. These stages are considered to be recapitulation of the developing process of the removing lymph pathways in vertebrate phylogenesis. The stomach lymphatic channel in vertebrate species examined is lined with a continous layer of endothelium cells.

Anatomy, Comparative↗
PubMed2003

Localization and macrostructure of subuterine lymphatic vessel networks in the bovine uterine broad ligament.

Localization and morphological features of lymphatic vessels leaving tissues of uterine horns and running through the broad ligament area were studied in mature cows after filling the lumen of the each lymphangion with varicoloured masses, mainly Microfil. The study has revealed that each branch of the lymphatic vessels emerged from both sides of the uterus and then formed double-layered networks, dorsal and ventral in the area of the mesometrium. The lymphatic branches under the uterus are very numerous and consist of enlarged precollector lymphangions. At the level of the ovary, the branches of vessels in both layers interweave each other forming the common pathway suggesting that lymph leaving the bovine uterus can be mixed in branches which are formed by elongated lymphangions running to lymphatic nodes.

Animals↗
PubMed1990

The migration of lymphocytes and polymorphonuclear leukocytes across the endothelial wall of the absorbing peripheral lymphatic vessel.

We studied the process of transendothelial migration of lymphocytes and polymorphonuclear leukocytes in the absorbing peripheral lymphatic vessels of small intestine and urinary bladder, under normal conditions, lymphatic stasis and prolonged fast. By ultrathin serial sections and three-dimensional models we found that lymphocytes and leukocytes share a common migration pathway from the interstitium into the lumen of the lymphatic vessel, namely 'the intraendothelial channel'. The migratory process of these cells occurs in several steps: approach to the endothelial wall, entry and run along the channel and finally coming out into lymphatic lumen. Our findings are compared with those concerning lymphatics in pathological conditions and blood vessels. Further considerations concern the possible mechanisms underlying this kind of transendothelial migration.

Animals↗
PubMed2005

Presence of bone marrow-derived circulating progenitor endothelial cells in the newly formed lymphatic vessels.

Bone marrow (BM)-derived circulating endothelial precursor cells (CEPCs) have been reported to incorporate into newly formed blood vessels under physiologic and pathologic conditions. However, it is unknown if CEPCs contribute to lymphangiogenesis. Here we show that in a corneal lymphangiogenesis model of irradiated mice reconstituted with enhanced green fluorescent protein (EGFP)-positive donor bone marrow cells, CEPCs are present in the newly formed lymphatic vessels. Depletion of bone marrow cells by irradiation remarkably suppressed lymphangiogenesis in corneas implanted with fibroblast growth factor-2 (FGF-2). Further, transplantation of isolated EGFP-positive/vascular endothelial growth factor receptor-3-positive (EGFP+/VEGFR-3+) or EGFP+/VEGFR-2+ cell populations resulted in incorporation of EGFP+ cells into the newly formed lymphatic vessels. EGFP+/CEPCs were also present in peritumoral lymphatic vessels of a fibrosarcoma. These data suggest that BM-derived CEPCs may play a role in "lymphvasculogenesis."

Animals↗
PubMed2005

Confirmation of mucin in lymphatic vessels of acquired cholesteatoma.

Abundant inflammatory cells infiltrate in the advancing front of the cholesteatoma perimatrix towards the middle ear mucosa. However, the cause of inflammation is not yet clear. The middle ear mucosa is often embedded in the cholesteatoma perimatrix. We hypothesized that the embedded mucosa is the cause of inflammation. Surgical specimens obtained from 20 cases of acquired cholesteatoma were used for the study. Lymphatic vessels were stained by the immunohistochemical method using the antibody against podoplanin. Mucin was simultaneously stained by alcian blue. The results of our examination were the following: (1) the presence of infiltrating mucin in the perimatrix; (2) the degeneration and reduction of lymphatic vessels; (3) the accumulation of inflammatory cells around morbid lymphatic vessels. Based on our findings, cholesteatoma can be defined as an inflammation affected by infiltrating mucin that escaped from embedded mucosa in the perimatrix.

Cholesteatoma, Middle Ear↗
PubMed2002

Kit-like immunopositive cells in sheep mesenteric lymphatic vessels.

Recent electrophysiological studies have suggested that there is a subpopulation of cells in lymphatic vessels which act as pacemakers controlling the characteristic spontaneous contractile activity in this tissue. In this study, electron microscopy and immunohistochemical techniques were used on sheep mesenteric lymphatic vessels to investigate the morphology of the cells comprising the lymphatic wall. The smooth muscle cells were not orientated in circular and longitudinal layers as is seen in the gastrointestinal tract, but were arranged in bundles which interlock and cross over in a basket-weave fashion. Antibodies to Kit and vimentin, which are widely used to label specialised pacemaking cells in the gastrointestinal tract (known as interstitial cells of Cajal), demonstrated the existence of an axially orientated subpopulation of cells lying between the endothelium and the bulk of the smooth muscle. Examination of this area using electron microscopy showed cells which were electron dense compared to the underlying smooth muscle and contained caveolae, Golgi complexes, mitochondria, 10-nm filaments, a well-developed endoplasmic reticulum and a basal lamina. The smooth muscle cells typically contained caveolae, dense bodies, mitochondria, abundant filaments, sER and basal laminae. Cells dispersed for patch-clamp studies were also stained for vimentin and myosin. Myosin-staining cells had the typical spindle appearance of smooth muscle cells whereas the vimentin-positive cells could either be branched or more closely resemble the smooth muscle cells. The present study provides the first morphological evidence that specialised cells exist within the vascular system which have the ultrastructural characteristics of pacemaker cells in other tissues and are vimentin and Kit positive.

Animals↗
PubMed2002

Evaluation of several methods used in anatomical investigations of the blood and lymphatic vessels.

The aim of this review is to describe the advantages and limitations of several methods used in anatomical investigations of intravisceral blood and lymphatic networks. The microangiographic methods as well as corrosion methods are described. In conclusion the authors confirmed that the most useful way for exploration of the blood and lymphatic vessels is to prepare corrosion casts. This paper focuses on the scanning electron microscopic examination of vascular corrosion casts. This method allows the examination of the three-dimensional organisation of vessels, including the blood and lymphatic capillaries. Imprints of endothelial cell nuclei can be observed on the surface of the blood and lymphatic vessels.

Animals↗
PubMed1975

[The relationship between the lymphatic vessels of the nerves of the human lower extremity and the perineural spaces].

The lymphatic vessels and perineural spaces of superficial and profound nerves of the extremity were studied on the material of 50 lower extremities of corpses of humans by the method of intratissue and direct injection. Initial lymphatic capillaries and extraorganic lymphatic vessels and their paravasal plexuses were found. It is concluded that closed lymphatic capillaries having no immediate connection with the perineural space are the roots of the lymphatic bed in the nerve.

Humans↗
PubMed2001

Review article: lymphatic vessel pumping and inflammation--the role of spontaneous constrictions and underlying electrical pacemaker potentials.

The lymphatic circulation is important in maintaining tissue fluid homeostasis. It removes fluid, proteins and other particles from tissue spaces and returns them to the blood stream. This function is achieved by rhythmical contractions of the collecting lymphatic vessels. The contractile mechanism is intrinsic to the smooth muscles present in the vessel wall and consequent to action potentials. The underlying electrical mechanism has been proposed to be due to rhythmic synchronization of Ca2+-dependent spontaneous transient depolarizations. The lymphatic pumping activity adapts to changes in fluid load and has been observed to augment during inflammatory reactions to help resolve the associated oedema. This beneficial action has been generally attributed to the increase in interstitial pressure consequent to the oedema. However, little attention has been paid to the possible role inflammatory mediators that are present in the lymphatic vessel environment, could play in directly affecting the lymphatic contractile mechanism. This review article discusses our current knowledge on the mechanism and initiation of lymphatic pumping and how these events are modulated during inflammatory conditions.

Animals↗
PubMed2006

Lymph node metastasis in breast cancer xenografts is associated with increased regions of extravascular drain, lymphatic vessel area, and invasive phenotype.

Interactions between the tumor stromal compartment and cancer cells play an important role in the spread of cancer. In this study, we have used noninvasive in vivo magnetic resonance imaging (MRI) of two human breast cancer models with significantly different invasiveness, to quantify and understand the role of interstitial fluid transport, lymphatic-convective drain, and vascularization in the regional spread of breast cancer to the axillary lymph nodes. Quantitative fluorescence microscopy was done to morphometrically characterize lymphatic vessels in these tumors. Significant differences in vascular and extravascular transport variables as well as in lymphatic vessel morphology were detected between the two breast cancer models, which also exhibited significant differences in lymph node and lung metastasis. These data are consistent with a role of lymphatic drain in lymph node metastasis and suggest that increased lymph node metastasis may occur due to a combination of increased invasiveness, and reduced extracellular matrix integrity allowing increased pathways of least resistance for the transport of extravascular fluid, as well as tumor cells. It is also possible that lymph node metastasis occurred via the cancer cell-bearing tumoral lymphatic vessels. The congestion of these tumoral lymphatics with cancer cells may have restricted the entry and transport of macromolecules.

Animals↗
PubMed2002

The connections of lymphatic vessels draining female reproductive organs with lymphnodes in the pig.

The connections of lymphatic vessels leaving the reproductive organs (ovary, oviduct, uterine horn, corpus and cervix, and vagina) with lymphnodes (normal and hemal) located in the uterine broad ligament and paraaortal regions were examined in the cyclic and immature pigs. To visualize the lymph pathways, the lymphatic lumen was filling with varicoloured microfil and/or ink-gelatin mass introduced all the way down to appearance in several nodes. This study revealed that lymphatics emanating from the uterine horn, corpus and the anterior part of the cervix demarcated large a lymphatic area in the porcine broad ligament. From the caudal portion of the cervix and vagina 2-3 lymphatics were found to emerge running near walls of these organs and connecting with large complex nodes, and 2-3 lymphatics reaching the plica urogenitalis. Generally, the lymphatic vessels leaving the porcine reproductive organs were connected by collector lymphangions with 3-5 normal-, 0-3 hemal- and one large composed nodes all found between the distal vascular subovarian plexus and the uterine artery as well as with 9-27 normal and 3-9 hemal nodes in the paraaortal region.

Adnexa Uteri↗