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PubMedDate not supplied

Lymphatic system of the pancreas.

A network of lymphatic vessels exists within the pancreas. The majority of vessels forming this network lie in the interlobular septa of connective tissue that subdivide the pancreas into lobes and lobules. Peripheral extensions of these interlobular lymphatics can be found within the lobules, but these intralobular lymphatics are relatively sparse. In the main, the intimate relationships of these internal pancreatic lymphatics are with the blood vessels and associated connective tissue. However in random areas, both intra- and interlobular lymphatics come into close relationship with acinar cells. Rarely are there lymphatics associated with islets of Langerhans, and then only where lymphatic vessels in connective tissue septa pass close to a pancreatic lobule that contains an islet at its periphery. Intra- and interlobular lymphatics are similar in structure. Both are thin walled having an endothelial lining and a delicate component of connective tissue. The pattern of interendothelial cell contacts and the sparsity of gaps between adjacent cells suggest that fluid movement through the intracytoplasmic system of vesicles is important in lymph formation in the pancreas. However intercellular transport is also likely to occur by a dynamic process involving fluid movement through dilatations between cells from interstitium to lymphatic lumen. Both exocrine and endocrine secretions of the pancreas may enter thoracic duct lymph directly in pancreatic lymph, but in normal circumstances this route of entry is not quantitatively important. The structural relationships between lymphatics and pancreatic parenchymal cells also make clear that lymph is not a significant pathway for their secretory products. Rather, the arrangement of lymphatics in the pancreas supports the view that lymph is primarily the drainage medium for substances that, for whatever reason, enter the interstitium. In addition, the low flow of lymph compared with that of plasma lends credence to the view that lymph is not a functionally important pathway for endocrine secretions from the pancreas to reach the blood. Both structural and functional evidence suggests that the proper functioning of the lymphatic system is of critical importance in the homeostasis of the pancreas. The lymphatic system of the pancreas, like that in other organs, is essential in the removal of excess fluid from the interstitium. In this sense, the lymphatics may be considered to serve as an overflow, protective, or safety system. When the system is inadequate or its capacity is exceeded, as in inflammation of the pancreas, exocrine secretions entering the interstitium are not cleared and the proteolytic enzymes cause major damage to the tissue. This, in turn, exacerbates the edema, accentuates the inability of lymphatics to drain the fluid, and results in further damage. The fibrosis that ensues damages the lymphatics either directly or through stricture of the surrounding connective tissue. In consequence, they become inadequate at an even earlier stage in subsequent attacks of inflammation and thereby predispose to chronic and recurrent pancreatitis. The larger interlobular lymphatics formed by the junction of their tributaries emerge upon the surface of the pancreas. There they travel primarily with blood vessels and stream toward a ring of lymph nodes that intimately surrounds the pancreas. A second system of nodes extensively involved in drainage from the pancreas is related to the front and sides of the aorta from the level of the celiac trunk to the origin of the superior mesenteric artery. This second set of nodes receives lymph either directly from the pancreas or indirectly from the first echelon of nodes that rings the organ. Although there is general agreement on the disposition of the groups within these sets of nodes, confusion results from the different classifications used by various authors. These classifications range from being purely descriptive, through an alpha and num

Animals↗
PubMed1982

Ultrasonographic diagnoses of major lymphatic system abnormalities prior to 20 weeks of pregnancy.

Prenatal ultrasound diagnoses of severe lymphatic system abnormalities were obtained in three fetuses. In all three cases the diagnosis was established prior to 20 wk of pregnancy, i.e. early enough to allow selective termination. In all three cases male fetuses with a chromosomal anomaly were found. Alpha-fetoprotein values were not elevated. In all cases the fetal abnormalities were of such size that surgical excision could not be taken into consideration to provide satisfactory results for the infants.

Abortion, Therapeutic↗
PubMed1988

[Features of the morphofunctional state of the organs of the thymico-lymphatic system during various adaptive reactions induced by electric stimulation of emotiogenic structures of the brain].

Weak electrical stimulation of emotiogenic brain structures was found to lead to the development of different general non-specific adaptation reactions. Stimulation of nucleus lateralis septi was found to evoke mainly the development of activation reaction, while stimulation of globus pallidum caused primarily the development of training reactions. Stress reactions were considerably less frequent in electrical stimulation of both kinds of structures than in the control. This can be explained by small values of the electrical current applied. Morphofunctional activity of thymus lymphatic system depended not only on the type of non-specific reaction but also on the character of the stimulated emotiogenic structure--the functional activity was higher with the stimulation of nucleus lateralis-septi. However, the functional activity of thymus lymphatic system in rats with globus pallidum stimulation was higher than in control rats that were not subject to any stimulation.

Adaptation, Physiological↗
PubMed1999

Homing of negatively charged albumins to the lymphatic system: general implications for drug targeting to peripheral tissues and viral reservoirs.

The present study shows the lymphatic distribution of the negatively charged anti-HIV-1 agents succinylated or aconytilated human serum albumins (HSAs) in rats. Quantitation of blood and lymphatic concentrations of these proteins was performed through fluorescence detection of the fluorescein isothiocyanate (FITC)-labeled proteins. At several time points after i.v. injection, samples were taken from the cannulated thoracic duct and the carotid artery. Distribution of the negatively charged albumins (NCAs) to lymph was much more rapid than that of albumin itself and was dependent on the total net negative charge added to the protein: the half-life times of lymphatic equilibration were 15, 30, and 120 min for FITC-labeled aconytilated HSA, FITC-labeled succinylated HSA, and FITC-labeled HSA, respectively. Lymph to blood concentration ratios of the studied compounds obtained at steady state approached unity. In addition, the fluorescence in both body fluids was shown to represent unchanged labeled proteins. It was therefore inferred that the NCAs efficiently passed the endothelial barrier from blood to the interstitial compartment. Subsequently, we studied whether a specialized process was involved in the endothelial passage of the NCAs to the lymph. The following observations supported such a mechanism: a) preinjection of the scavenger receptor blockers polyinosinic- and formaldehyde-treated HSA reduced the transport from blood to the lymphatic compartment of FITC-labeled aconytilated HSA by more than 90%; b) the rate of lymphatic distribution was largely reduced when the body temperature of the rat was lowered to 28 degrees; and c) pre-administration of chloroquine resulted in a significant reduction in the lymphatic distribution of the NCAs. These data collectively indicate that a scavenger receptor-mediated process is involved in the transendothelial transport of NCAs. In situ localization in lymph nodes of the rat showed that FITC-labeled aconytilated and succinylated HSA are mainly present in the germinal center and parafollicular zones. The efficient distribution of these anionized proteins to the lymphatic system is of particular interest for HIV therapy, taking into account that replication of HIV mainly takes place in the lymphoid system. The observation that macromolecules, through charge modification, can extravasate through a receptor-mediated transcytotic process is potentially of major importance for the delivery of drugs with macromolecular carriers to cells not directly in contact with the blood.

Albumins↗
PubMed1989

Radiological protection and the lymphatic system: the induction of leukaemia consequent upon the internal irradiation of the tracheobronchial lymph nodes and the gastrointestinal tract wall.

The excess of leukaemia among young people living in the vicinity of the nuclear fuel reprocessing plant at Sellafield has focused attention on the possibility that irradiation of the lymphatic system from particulate alpha-emitting nuclides might be responsible. We discuss below two possible routes of such exposure; namely the inhalation and ingestion of particulates. We conclude that, in spite of the real possibility of substantial doses to tissues associated with the lymphatic system, there is little reason to expect that lymphatic leukaemia will be the dominant outcome of the exposure. However, the arguments presented are not, and cannot be, wholly conclusive.

Administration, Inhalation↗
PubMed1975

[Anatomical revision of the lymphatic system of the mammary gland (200 cases)].

The author has made an Anatomical Review of the Lymphatic System of the Mammary Gland on the Base of the study of 200 cases. Three main lymphatic pedicles and their respective subpedicles are described. It was not observed that the mammary lymph drains to the contralateral side or by a direct route to the nodes of the supraclavicular region. The author describes some nodes which are not previously mentioned in the literature, presents a new classification of the axillary lymphatic nodes from an anatomical point of view. This study is still under execution.

Breast↗
PubMed1990

Congenital abnormalities of the lymphatic system: a new clinical classification.

The numerous clinical presentations of congenital abnormalities of the lymphatic system in children and the confusing terminology used to describe their pathologic diagnoses impede the physician's understanding of the condition. The clinical classification based on the actual symptoms of the congenital problems we have presented here should help the physician identify the specific abnormality and a potential treatment. Future research should concentrate on the specific causes and the treatment of these congenital abnormalities.

Adolescent↗
PubMed1988

Kaposi's sarcoma: evidence supporting its origin from the lymphatic system.

The histogenesis of Kaposi's sarcoma (KS) remains a subject of dispute. The weight of evidence, however, favors derivation of the spindle cell of KS from the lymphatic system and very likely from lymphatic endothelium. This conclusion is based on light microscopic and morbid anatomical observations and is further supported by the unique distribution of lesions in the skin, and in the submucosa of the gastrointestinal tract, following the lines of lymphatics; by the remarkable predilection of KS for lymph nodes (often without skin lesions); by the absence of lesions in organs which are devoid of lymphatics, i.e. the brain and eyeball; and by observations made by the author and others, utilizing electron microscopy, enzyme histochemistry and immunohistochemistry. It is recognized nonetheless that reactive elements such as fibroblasts, myofibroblasts and histiocytes may also be involved in the proliferative process.

Endothelium↗