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At least 235 records · Page 13Linked to original sources
PubMed2001

Spontaneous reanastomosis between lymphatic vessels following syngeneic transplantation of the small intestine in the rat.

Spontaneous lymphvascular reanastomosis (SLR) following small bowel transplantation in rats is of clinical relevance for the resorption of long chain fatty acids. Detailed morphological and molecular data concerning the process of lymphvascular reanastomosis are not available in the literature. In this study SLR was investigated using microradiology and scanning electron microscopy. Between the 8th and 21st postoperative days following transplantation SLR does not occur between the intestinal trunk of the transplant and the thoracic duct of the recipient. Instead, an indirect connection was observed between the inserted advential lymphatic vessels of the mesenteric artery and lymphatic vessels of the aorta or ductus deferens, which are connected with the thoracic duct.

Animals↗
PubMed2004

Regrowth of lymphatic vessels following transection of the muscle coat in the rat small intestine.

Regeneration of lymphatic vessels after transection of the muscle coat in the rat jejunum was studied by histochemical methods. The lymphatic regrowth occurred behind the regeneration of blood vessels. Enzyme histochemistry for 5'-nucleotidase (5'-Nase) demonstrated the manner of lymphatic regrowth, which was essentially attributed to vascular sprouting from preexisting lymphatics, and structural changes of the endothelial cells indicating their high migratory potential. The lymphatic regeneration progressively advanced with vascular maturation throughout the experimental period. The expression of 5'-Nase in the regenerating lymphatics was increased in proportion to their growth. VEGF-C, a highly specific lymphangiogenic factor, was highly expressed in a subpopulation of interstitial cells, being close to the regrowing lymphatics with immunoreactivity of its receptor, VEGFR-3, in the regenerative area. The present findings suggest that transection of the intestinal muscle coat affords a useful experimental model for the investigation of lymphatic regeneration in tissue repair and that the interstitium may play a crucial role in lymphangiogenesis.

5'-Nucleotidase↗
PubMed2004

Lymphatic vessel density is significantly increased in melanoma.

BACKGROUND: Melanoma is well known for its ability to involve regional lymph nodes in the early stage. However, the presence of lymphangiogenesis in melanoma is still controversial due to lack of lymphatic-specific markers. The purpose of this study was to determine the intra- and peritumoral lymphatic vessel density (LVD) using a novel lymphatic vessel-specific marker D2-40 and compare it to general vessel density (GVD) as determined by CD31 immunostaining in a series of melanocytic lesions. METHODS: The intra- and peritumoral GVD and LVD were examined by immunohistochemistry using D2-40 and CD31 antibodies in a series of melanocytic lesions. RESULTS: We found significantly higher intratumoral LVD in melanomas as compared to either common acquired or dysplastic nevi (p < 0.01). Although peritumoral LVD in melanoma and malignant melanoma in situ was higher compared to nevi, the difference did not reach statistical significance (p = 0.059). There was no significant difference in GVD among the various groups of melanocytic lesions. CONCLUSIONS: Our results show that intratumoral LVD is significantly increased in melanomas compared to benign nevi. The higher intratumoral lymphatic density in invasive melanomas suggests that melanoma cells might promote lymphangiogenesis. In addition, assessment of intratumoral LVD may be potentially useful in the differential diagnosis of melanocytic lesions.

Antibodies, Monoclonal↗
PubMed1999

Lymphatic vessel hypoplasia in fetuses with Turner syndrome.

Turner syndrome is associated with subcutaneous accumulation of fluid in the neck region that can be visualized sonographically from 10-14 weeks of gestation as massively increased nuchal translucency thickness. Possible mechanisms for this increased translucency include dilatation of the jugular lymphatic sacs because of developmental delay in the connection with the venous system, or a primary abnormal dilatation or proliferation of the lymphatic channels interfering with a normal flow between the lymphatic and venous systems. The aim of this study was to investigate the distribution of lymphatic vessels in nuchal skin tissue from fetuses with Turner syndrome compared with fetuses carrying trisomies 21, 18 and 13 and chromosomally normal controls. The distribution of vessels was examined by immunohistochemistry using a monoclonal antibody, PTN63, against 5' nucleotidase and an anti-laminin antibody. In normal control fetuses (n = 6) and those with trisomies 21 (n = 3), 18 (n = 2) and 13 (n = 2), PTN63-positive and laminin-positive vessels were evenly distributed throughout the dermis and subcutis. In Turner syndrome (n = 3), there was a chain of large vessels that stained with both PTN63 and laminin at the border between dermis and subcutis, but there was scarcity of vessels in the upper dermis and the subcutis. Using PTN63 alone, there were no positive vessels in the upper dermis. We conclude that in Turner syndrome lymphatic vessels in the upper dermis are hypoplastic.

Chromosomes, Human, Pair 13↗
PubMed1975

Biomechanics of a lymphatic vessel.

The principles of mechanics and the current notions of lymphatic physiology are integrated into a simple mathematical model of a lymphatic vessel which establishes a theoretical base for lymph propulsion in the lymphatic system. The model specifically considers the active and passive contractilities of the lymphatics. The model is simulated on a digital computer. The pressure and flow patterns derived from the model are consistent with the currently available experimental data.

Biomechanical Phenomena↗
PubMed2003

Division of lymphatic vessels at varicocelectomy leads to testicular oedema and decline in testicular function according to the LH-RH analogue stimulation test.

OBJECTIVES: To study the andrological outcome of the division of testicular lymphatic vessels at varicocelectomy in children and adolescents. METHODS: Testicular size and basal and stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) values were determined prospectively in 86 patients with left unilateral varicocele grades II-III. 22 patients underwent lymphatic non-sparing surgery (LNS group), 10 of them with artery sparing (LNS/AS) and 12 without artery sparing (LNS/ANS), 23 patients underwent lymphatic sparing repair (LS group) and 41 patients were treated conservatively (NT group). RESULTS: The LNS group demonstrated significantly greater left testicular enlargement at six weeks and one year following repair, left testicular hypertrophy developed in 31.8% and hydrocele in 22.7% of patients. Marked oedema of intertubular tissue and a varying degree of tubular injury was observed in boys surgically treated for hydrocele. In the LS group, neither hypertrophy nor hydrocele developed postoperatively, the LH stimulated values were lower than in LNS/ANS group (p<0.05) and the NT group (p<0.04), the FSH stimulated values were lower than in the LNS/ANS group (p<0.001). CONCLUSIONS: Division of lymphatic vessels at varicocelectomy is associated with an excessive increase in testicular volume due to oedema, and with a reduced testicular function according to higher LH and FSH stimulated values. Preservation of lymphatics is strongly advised in varicocelectomy in adolescents to ensure better andrological outcome.

Adolescent↗
PubMed1994

Pressure-flow relationships in isolated sheep prenodal lymphatic vessels.

The objective of this study was to determine how isolated sheep prenodal popliteal lymphatic vessels responded to transmural and outflow pressure changes. Afferent lymphatics (0.5-1.0 mm diameter) were suspended in an organ bath with both inflow and outflow ends cannulated. Input to the duct was provided from a reservoir filled with Krebs solution. Two types of experiments were performed. In one group, a transmural pressure was applied to the ducts. In a second group of studies, the inflow pressure was fixed (at 2, 4, or 6 cmH2O) and the outflow pressure was increased in 4-cmH2O increments. The transmural pressure-flow relationship was expressed as a bell-shaped curve with pumping increasing up to 18-26 cmH2O and declining at higher pressures. Maximum flow rates averaged 1.4 +/- 0.6 ml/10 min. Greater than 50% of maximum pumping activity was available between approximately 12 and 43 cmH2O. In response to outflow pressures, variable responses were observed. In some vessels, elevations of outflow pressure had little impact on flow rates, until high outflow pressures were attained. In other ducts, pumping declined in response to outflow pressure challenge. With lower inflow pressures (2 or 4 cmH2O), flow rates occasionally increased with elevations of the outflow catheter. In ducts preset with inflow pressures of 6 cmH2O, the mean stop-flow pressure was 60 +/- 4.6 cmH2O. In comparison with previously published data on the pressure-flow relationships in postnodal lymphatics, prenodal vessels pumped over a larger range of transmural or outflow pressures.

Animals↗
PubMedDate not supplied

Constriction of canine prenodal lymphatic vessels following the intra-arterial injection of vasoactive agents and hemorrhage.

In the forelimbs of anesthetized dogs, perfused at constant arterial inflow, we measured the pressure in a prenodal lymphatic vessel before and following arterial hemorrhage to a mean systemic arterial pressure of approximately 55 mmHg. We also made bolus intra-arterial injections of 1 microgram epinephrine and arginine vasopressin or 20 micrograms dopamine, prostaglandin F2 alpha and tyramine. Hemorrhage and all vasoactive substances significantly increased forelimb perfusion pressure and skin small artery pressure. Skin small vein pressure was significantly decreased by hemorrhage or injection of epinephrine, dopamine or tyramine, but was not significantly altered by arginine vasopressin or prostaglandin F2 alpha. Mean systemic arterial pressure was decreased by hemorrhage, increased by arginine vasopressin, tyramine and prostaglandin F2 alpha but remained unchanged following the injection of either epinephrine or dopamine. Lymphatic pressure was significantly increased following hemorrhage or the injection of all vasoactive agents. The increase seen with tyramine was small but consistent and thus statistically significant. These data indicate that the prenodal lymphatic vessels of the canine forelimb actively constrict in response to the neural and/or hormonal consequences of arterial hemorrhage or the introduction of exogenous vasoactive substances into the arterial blood supply to the forelimb. The results of the current study support the possibility that lymphatic function, through activation of lymphatic smooth muscle, is subject to neural and/or hormonal regulation in certain physiological and/or pathophysiological states.

Animals↗
PubMed2003

The localization and connections of suboviductal lymphatic vessels in the bovine uterine broad ligament.

The distribution of oviductal lymphatic vessels in the bovine mesosalpinx and bursa ovarica, and their communications with other lymphatics in the uterine broad ligament were examined after exposition of all lymphatic pathways with varicoloured microfil and/or ink-gelatin mixture. However, filling of the lumen of the oviductal infundibulum lymphatics was difficult or impossible because of its slender walls. Lymphatics of the isthmus and ampulla with short precollectors formed branches 1.5-2.0 cm long on both sides: dorsal and ventral of the uterine broad ligament. Collectors with slender and long lymphangions, visible after filling their lumen, encircled the alymphatic area in the parainfundibullar mesosalpinx. The greatest number of lymphatic branches, which originated from the paraisthmal part of the oviductal ampulla were observed in the subovarian area. The characteristic feature was their immediate proximity with uterine and oviductal arterial vessels. Subsequent studies have provided convincing evidence that there are direct connections of lymphatics leaving the oviduct and ovarian sac with lymphatics emerging from the uterus and ovary (after bilateral filling of lymphatics pathways in the whole broad liagment of the uterus). The performed investigations showed particularly characteristic feature in the cow--mixing lymph leaving various reproductive organs in the area of the right and left ligament--before two long collector branches reach the nearest lymphatic node/-s.

Animals↗
PubMed2005

[Lymphatic vessels and cancer].

Survival and development of tumors depends on nutritional and respiratory biological events and exchanges ensured by blood and lymph. Tumor proliferation is associated with an increase in the vascular networks either near the tumor or intra-tumorally. Tumor tissues are able to increase their provisionment according to their needs while directing and optimizing the development of peri-tumoral vessels. The production of growth factors stimulating neo-formation of lymphatic vessels by cancer cells constitutes one of the adaptations responsible for metastatic propagation. During tumor development the lymphatic system is considered in many cases of cancer as the primary means of metastasis dissemination. The study of the lymphatic system setting and ways to block it are important points to consider in oncology.

Cell Proliferation↗
PubMed1994

Regeneration of mesenteric lymphatic vessels in a new experimental model of orthotopic intestinal transplantation in rats.

A new experimental model of orthotopic intestinal transplantation was performed using microsurgical techniques in rats; the physiological flow of blood, lymph, and food was reconstructed. Regeneration of mesenteric lymphatic vessels, which plays an extremely important role in lipid absorption of the transplanted intestine, was studied by mesenteric lymphangiography. Regeneration of mesenteric lymphatic vessels was first confirmed on the seventh postoperative day by mesenteric lymphangiography, and favorable regenerative patterns, without obstruction, were observed on the 32nd, 58th, and 93rd postoperative days.

Animals↗
PubMed1991

[Tumor embolization to the lymphatic vessel structures of the bladder wall (L+). Its effect on the course of bladder tumors].

A retrospective study was conducted in patients with bladder tumors equal to or higher than stage T1 to determine the influence on survival of tumor cell invasion of the microscopic lymphatic vessels of the bladder wall. Sixty-two patients were studied (34 recurrent and 28 primary tumors). Evidence of microscopic lymphatic invasion was disclosed following TUR (48 cases) and cystectomy (14 cases). Overall and with a mean follow up of 27 months, 25% of the patients are alive and tumor free, 51.6% had died from the tumor (90% less than 3 years following diagnosis). Forty-five percent had lymph node metastasis and 56.6% node and organ metastases. For a time interval of over 6 months between the diagnosis of L + and definitive treatment, there was an 80% mortality versus 43% when treatment was concurrent with diagnosis. Finally, survival was much better in patients submitted to radical surgery. We can conclude from the present study that evidence of tumor invasion of the lymphatic vessels must be routinely sought by the pathologist in order to identify those patients with a high probability of tumor dissemination.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Arrangement and fine structure of lymphatic vessels in the human spermatic cord.

The arrangement and architecture of lymphatic vessels in the human spermatic cord was investigated using ink injection methods, and light and electron microscopy. Near the testis lymphatic capillaries are found in close association with the ductus deferens and are grouped like alveoles where collecting vessels emerge. Collecting vessels are arranged at the periphery of the plexus pampiniformis decreasing in number towards the inguinal canal. Single smooth muscle cells are found in the wall of the initial segments of the collecting ducts. In the proximal part of the spermatic cord most of the lymphatics have several layers of muscle cells in their wall. But at places where collecting vessels are equipped with valves the muscular coat is almost completely interrupted. Thereby functional units are established, consisting of one valve and the following intervalvular segment which measures 2-3 mm in length.

Adolescent↗