A fibrillar elastic apparatus around the wall of human lymph capillaries is demonstrated by means of histochemical and ultrastructural techniques. This apparatus consists of three interlinked components listed here in order of increasing distance from the capillary wall: 1) oxytalan fibres connected to the abluminal surface of the endothelial cells, known also as "anchoring filaments" and consisting of bundles of microfibrils; 2) elaunin fibres consisting of microfibrils and a small amount of elastin; and 3) typical elastic fibres consisting of microfibrils and abundant elastin. The microfibrillar constituent has similar ultrastructural features in the three components of the elastic apparatus. Microfibrils have a diameter of 12-14 nm, an electron-transparent core and a wall with 3-5 electron-dense subunits and oblique cross striations with a period of 15-17 nm. Microfibrils are the common element of the three components of the elastic apparatus and they link them to one another and to the elastic network of the perivascular connective tissue. An elastic apparatus was not found around blood capillaries and it can thus provide a histological marker to identify lymph capillaries. The possible role of the lymphatic elastic apparatus in the physiological activity of the lymphatic absorbing network is discussed and it is proposed that its disconnection from the elastic network of the tissue may promote pathological conditions such as lymphoedema or diseases related to impaired immune responses.

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Three sisters (ages 27, 24, and 17 years) presented with slowly progressing dystonic dementia and spastic tetraparesis with infantile onset. CSF, bone marrow, and conjunctival cells showed storage vacuoles. Biochemical analysis revealed increased urinary oligosaccharide excretion and decreased activity of acid beta-D-galactosidase and beta-D-fucosidase in serum, leukocytes, and cultured fibroblasts. The parents' enzyme values were in the heterozygous range. This is the only case in the literature of severe dementia associated with the clinical symptoms of type 3 GM1 gangliosidosis. The clinical heterogeneity of GM1 gangliosidosis and the significance of the combination of beta-D-galactosidase and beta-D-fucosidase defects in this syndrome are discussed.

In a previous paper we have shown that guinea pig mesentery lymph collectors possess not only autonomic nerve fibers containing classical neurotransmitters but also peptidergic ones. These nerve fibers are sensitive to the depletory action of capsaicin, and are likely to be sensory in nature.Therefore the aim of this study was to evaluate the effects of capsaicin of the nerve fibers of the lymphatic wall by ultrastructural methods and to study the distribution of the “capsaicin sensitive” nerve fibers in the lymphatic vessel wall.

Amphibians have paired muscular pump organs, called “lymph heart”, which rhythmically pump back the lymph from the large subcutaneous lymph sacs into the veins. The structure and ultrastructure of these organs is well known but to date there is a lack of information about the innervation of lymph hearts. Therefore has been carried out an ultrastructural study in order to study the distribution of the nerve fibers, and the morphology of the neuromuscular junctions in the lymph heart wall.