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[Experimental verification of the possibility of isolation perfusion of the lymphatic system].

The possibility of isolating the lymphatic system from the circulatory system by draining the thoracic lymphatic duct and infusion of different agents (Evans blue, kanamycin, staphylococcus, sodium thiopental and potassium chloride) to the peripheral lymphatic vessels was examined in 22 fresh cadavers and 65 mongrel dogs. The release of the agents to the blood vessels did not occur if the volumetric consumption of intralymphatic infusion did not exceed 0.3 ml/min per peripheral vessel. Both the outflow and toxicity of the lymph from the thoracic duct increased while conducting the perfusion of the lymphatic system by autolymph.

Animals↗

The pathomechanism of posttraumatic edema of the lower limbs: II--Changes in the lymphatic system.

BACKGROUND: The peripheral lymphatic system reacts to penetrating microorganisms and self-antigens released from tissues and cells damaged by trauma or intracellular pathogens. The response of regional lymph nodes to tissue trauma has not been thoroughly studied. We investigated the changes in lower limb lymphatics and nodes after fractures and soft tissue injuries. This type of injury is frequently complicated by limb edema. Posttraumatic edema of lower limbs is characterized by long-lasting swelling of the limb, erythema, and increased skin temperature at the site of injury. This suggests that a local inflammatory process is proceeding, even though the process of bone or soft tissue healing is considered to be completed. METHODS: Twenty-one patients with closed lower limb bone fractures and soft tissues injuries were studied by means of isotope lymphography. RESULTS: Dilated lymphatics of the entire limb were found in all patients, and 62% of them showed enlarged inguinal lymph nodes. Venous thrombosis was found in 24% of cases. There was no correlation between the degree of lymphatic dilatation, lymph node enlargement, and bone fracture or soft tissue injury or venous thrombosis. Surgical intervention was not an independent factor for lymph node enlargement. CONCLUSION: This study has shown that although the fracture or injured tissues are clinically healed, local inflammatory reaction at the site of injury persists and cytokine signals are sent to the regional lymph nodes.

Adolescent↗

Pancreatic lymphatic system in rodents.

The lymphatic network of the pancreas has been little investigated and recent studies have provided contrasting data. This research is aimed to supply the morphologic basis to outline the involvement of the lymphatic system in pancreatic pathology. Guinea pigs, rats, and mice were anesthetized with ether and sacrificed with the same anesthetic. Pieces of pancreas were processed for transmission electron microscopy. Semithin sections were observed by light microscopy and, after positive identification by transmission electron microscopy, lymphatics were followed with long series of consecutive sections to define their distribution. Lymphatics were detected in the pancreas of all the animals both in the inter and the intralobular sites. Closer relations with the exocrine parenchyma (ducts and acini) were observed in guinea pig pancreas. Remarkably, interesting relationships between lymphatics and endocrine tissue were observed in all the animals. Overall, however, the lymphatic network of rat pancreas was less develop and preferentially associated with blood vessels. The distribution of the pancreatic lymphatic network appears consistent with an active role in pancreatic pathology.

Animals↗

[Current methods for investigation of the lymphatic system (author's transl)].

Investigation of the lymphatic system attracts an ever increasing interest not only of scientists working in the theoretical field but also of clinicians. Therefore it is no wonder that numerous methods for the study of the lymphatic system have been proposed. The present article surveys a great number of these methods, and particular emphasis is given to the work that has been and is being carried out in the Soviet Union. It is shown that a detailed knowledge of the lymphatic system is essential if a holistic view of the structure and function of a particular organ is to be obtained.

Animals↗

The lymphatic system in body homeostasis: physiological conditions.

The lymphatic system is an organized network composed of functionally interrelated lymphoid tissue, and transportation pathways of tissue fluid/lymph and lymphoid cells. Its main components are 1. migrating dendritic cells, macrophages and lymphocytes, organized lymphoid tissue such as lymph nodes, thymus, spleen, bone marrow, and lymphoid tissue in gut and lungs, liver lymphoid cells, and the dendritic cell network of nonlymphoid organs; 2. vessels (intercellular space, lymphatics, and perivascular spaces); 3. fluids (tissue fluid and lymph). The lymphatic system can be divided into the following compartments: peripheral (from the interstitial space to and within the nearest lymph node), and central (efferent lymphatics, cysterna chyli, and thoracic duct, all lymphoid organs). Organs and tissues with the most active afferent arm of the lymphatic system are skin, gut, and lungs. These are the body structures exposed to the external environment. All other nonlymphoid bodily tissues are also percolated by tissue fluid/lymph, and contain a network of dendritic cells and macrophages. Data obtained from normal human subjects on lymph composition and flow are presented. Future trends in lymphatic research are outlined.

Animals↗

Imaging the lymphatic system: possibilities and clinical applications.

The lymphatic system is anatomically complex and difficult to image. Lymph ducts are responsible for the drainage of part of the body's interstitial fluid. Lymph nodes account for the enrichment of lymph fluid, and can be involved in a large variety of diseases, especially cancer. For a long time, lymphatic imaging was limited to the sole use of conventional lymphography involving invasive procedures and patient discomfort. New contrast agents and techniques in ultrasound, nuclear medicine, and MR imaging are now available for imaging of both the lymphatic vessels and the lymph nodes. The objective of this review is to discuss the different imaging modalities of the lymphatic system, with a special focus on the new possibilities of lymphatic imaging including enhanced MR lymphography, sentinel node and positron emission tomography imaging, and contrast-enhanced ultrasound.

Contrast Media↗

"Artificial lymphatic system": a new approach to reduce interstitial hypertension and increase blood flow, pH and pO2 in solid tumors.

A mechanical drainage system, the "artificial lymphatic system" (ALS), consisting of a vacuum source and drain, is evaluated for its ability to aspirate the interstitial fluids responsible for the elevated interstitial fluid pressure (IFP) observed in solid tumors. IFP, pH, and pO2 radial profiles were measured before and after aspiration using wick-in-needle (WIN) probes, needle pH and oxygen electrodes, respectively. Laser Doppler flowmetry measured temporal changes in blood flow rate (BFR) at the tumor surface during aspiration. The WIN probe and IFP profile data were analyzed using numerical simulation and distributed mathematical models, respectively. The model parameter, P(E), reflecting central tumor IFP, was reduced from 15.3 to 5.7 mm Hg in neuroblastoma and from 13.3 to 12.1 mm Hg in Walker 256, respectively, following aspiration. The simulation demonstrated that spatial averaging inherent in WIN measurements reduced the calculated magnitude of the model parameter changes. IFP was significantly lower (p<0.05), especially in regions surrounding the drain, and BFR was significantly higher (p<0.05) following 25 and 45 min of aspiration, respectively; pH and pO2 profiles increased following aspiration. The experimental and mathematical findings suggest that ALS aspiration may be a viable way of reducing IFP and increasing BFR, pO2, and pH and should enhance solid tumor chemo and radiation therapy.

Animals↗

Morphological studies of the cardiac lymphatic system.

The distribution and structure of the mammalian cardiac lymphatic system have been investigated by puncture injection, intra-arterial injection of silver nitrate, hydrogen peroxide immersion, and light and electron microscopy. The cardiac lymphatic system consists of drainage vessels and lymphatic capillaries. The drainage vessels contain many valves and are mainly situated subepicardially following branches of the coronary artery. The lymphatic capillaries are composed of a thin layer of endothelial cells, and form relatively dense networks in a fishnet arrangement. These lymphatic networks are richer in the ventricles than in the atria, being present in the subepicardial myocardial and subendocardial regions. In addition, networks are found in all cusps of the atrioventricular valves, and in the sinuatrial node and atrioventricular system. The lymphatic system maintains cardiac homeostasis by receiving proteins, electrolytes and excess fluid from the interstitial tissue and returning them to the venous system.

Animals↗

[The lymphatic system--terra incognita? Demonstrated by morphological assessment of resorption processes].

The lymphatic system has been demonstrated by means of special microscopic investigations, using morphologically comprehensive resorption procedures. References has been made to the literature which gives an account of the available knowledge about the lymphatic system and the scientific concepts produced in the course of the centuries. After going into the fundamental morphological principles of parenteral resorption and resorption in the bovine uterus, a description is given of the transport of the vital dyes patent blue violet and Japanese ink, which was followed microscopically in the lymphatic system. A further phenomenon emerges with the concept of persorption, where the particles are in the micron range and have also been identified microscopically in the pathways of the lymphatic system.

Animals↗

Transfer of different nonsteroidal antiinflammatory drugs via the lymphatic system in the rat.

The motility of lymphatic vessels is regulated by arachidonate metabolites and can, therefore, be altered by cyclooxygenase blockers such as nonsteroidal antiinflammatory drugs (NSAIDs). To investigate the transfer of different NSAIDs via the lymphatic system, pharmacokinetics in plasma and lymph after peroral administration of three model compounds (namely, racemic ibuprofen, tenoxicam, and nabumetone) were investigated in rats. Microsurgical cannulation of the thoracic duct allowed cumulative sampling of lymph fluid up to 48 hr (N = 16). Pharmacokinetic parameters in plasma were determined in a control group (N = 12). Concentrations of R-ibuprofen, S-ibuprofen, tenoxicam, nabumetone, and the metabolites OH-ibuprofen, COOH-ibuprofen and 6-methoxy-2-naphthylacetic acid (6MNA; a metabolite of nabumetone) were monitored in lymph and plasma by HPLC. The observed peak concentrations in lymph of the investigated drugs are likely to produce different biological effects with regard to cyclooxygenase-1 inhibition. To quantify the appearance in lymph fluid, a "lymphatic clearance" of the investigated compounds was defined by dividing the amount recovered in lymph by the corresponding area under the plasma concentration-time curve. The "lymphatic clearance" differed substantially between the investigated compounds (mean +/- SD: R-ibuprofen, 19.8 +/- 9.4; S-ibuprofen, 9.6 +/- 3.6; tenoxicam, 32.5 +/- 31.3; nabumetone, 133.6 +/- 75.2; 6MNA, 18.3 +/- 8.5 microliters/min/kg). Overall recovery of the investigated compounds in lymph did not exceed 5% of the doses given. The known fact that lymphatic drainage is regulated by arachidonate metabolites suggests that NSAIDs differing in their transfer via the lymphatic system could result in different responses of lymphatic vessels to an inflammatory fluid load.

Animals↗

Prox1 function is required for the development of the murine lymphatic system.

The lack of specific markers has raised problems in documenting the precise manner by which the lymphatic system develops. Here we report that the homeobox gene Prox1 is expressed in a subpopulation of endothelial cells that by budding and sprouting give rise to the lymphatic system. The initial localization of these cells in the veins and their subsequent budding are both polarized, suggesting that unidentified guidance signals regulate this process. In Prox1 null mice, budding and sprouting is arrested, although vasculogenesis and angiogenesis of the vascular system is unaffected. These findings suggest that Prox1 is a specific and required regulator of the development of the lymphatic system and that the vascular and lymphatic systems develop independently.

Animals↗

Exercise and the lymphatic system: implications for breast-cancer survivors.

This article summarises the current research on the lymphatic system related to exercise and critically evaluates the implications for exercise performance by breast-cancer survivors. The primary role of the lymphatic system during exercise is to assist in the regulation of tissue volume and pressure by carrying fluid and plasma proteins that have leaked into the interstitial space from tissues back to the cardiovascular system. During steady-state exercise in humans, lymph flow has been shown to increase to levels approximately 2- to 3-fold higher than at rest. Although the lymphatic system does not typically limit exercise performance in the normal population, the function of this system can be impaired in 27-49% of women who have survived breast cancer. Breast cancer-related lymphoedema (BCRL) is a chronic swelling that can occur in the ipsilateral hand or arm of women treated for breast cancer and results in a number of physical and psychological sequelae. Exercise was once believed to be a factor in the development of BCRL as it was thought that the damage to the axillary lymphatics from breast-cancer treatment resulted in a primary obstruction to lymph flow. However, the exact aetiology and pathophysiology of BCRL appears to be multi-factorial and not as simple as a 'stop-cock' effect. Furthermore, recent studies have shown that participating in vigorous, upper-body exercise is not related to an increase in arm volume, which would indicate the development of BCRL. It is still not known, though, how long-term exercise affects lymphatic system function in breast-cancer survivors with and without BCRL.

Breast Neoplasms↗

A new radiographic cadaver injection technique for investigating the lymphatic system.

Studies of the gross anatomy of the lymphatic system are few and far between when compared with those of other vascular systems. Our knowledge of the anatomy of the lymphatic system is so limited that it seems vastly inadequate in explaining the clinical manifestations caused by its disorder. This study has developed an effective method to identify the lymphatics using hydrogen peroxide, to demonstrate the lymphatic vessels radiographically using a lead oxide suspension, and to dissect them out in adult human cadavers.

Animals↗

Radiolabeled colloids and macromolecules in the lymphatic system.

The scintigraphic technique to investigate the lymphatic system is based on a good knowledge of basic criteria in order to correctly interpret the findings. This article penetrates these criteria, updates the present knowledge, and covers basic science work and clinical applications. The anatomy, physiology, and pathology of the lymphatic system are covered. Basic criteria for the radiopharmaceuticals to be used are described as well as their quality control. The principles for lymphoscintigraphy are described. The dosimetry in lymphoscintigraphy as well as radiation risk is estimated for different procedures. Experimental animal studies are summarized. Clinical applications cover staging procedures for breast cancer, malignant melanoma, pelvic neoplasms, and lymphoma. Lymphadenoectomy follow-up studies are also included. The use of lymphoscintigraphy in radiotherapy dose planning is described as well as lymphatic function studies in, e.g., edema and lymph transplantations.

Colloids↗