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Biomedical subjects

T Waris

Publications and source records attributed to T Waris.

At least 73 records · Page 4Linked to original sources
PubMed1983

Reinnervation of human skin grafts: a histochemical study.

The reinnervation of nine human skin grafts was investigated using histochemical thiocholine methods for the demonstration of cholinesterases. The regenerated cutaneous nerves showed both specific acetylcholinesterase and nonspecific cholinesterase reactions. In the youngest specimens, taken 3 weeks after the grafting, such regenerated nerves were seen both at the subdermal level under the graft and at the margins of the graft. These nerves seemed to orient toward the denervated graft area. The growing nerves were generally distributed in a random fashion. The reinnervation of some hair follicles, erector pili muscles, and sweat glands were observed in well-innervated full-thickness and thick partial-thickness skin grafts. It is suggested that this target-organ control of regenerating nerves occurs as a result of the action of chemotactic factors. A well-innervated graft bed seems to be important for optimum reinnervation of skin grafts. Fibrosis and scarring seem to hamper nerve regeneration.

Acetylcholinesterase↗
PubMed1983

Cardioplegia versus topical cooling for cardiac protection during open-heart surgery. An electron microscopic and histochemical study of right atrial biopsies.

The effectiveness of topical cooling and cold cardioplegia for cardiac protection in the course of open-heart surgery was studied by electron microscopy and fluorescence microscopy of right atrial biopsies. In 20 patients with topical cooling, no changes or minimal changes were observed in 15 cases, more pronounced changes in 3 cases, and severe destruction in 2 cases. In the group of 20 patients with cold cardioplegia the range of the changes was significantly narrower: no specimen remained completely intact; on the other hand, very severe destruction was not observed. Fluorescence microscopy revealed that the neural noradrenaline stores were relatively resistant to ischaemia. Electron microscopy showed certain failure of the protective procedure, resulting in injury of myocardial cells and neural elements. Even "spot-like" destruction noted in the nerve terminals may interfere with the peripheral neuro-neuronal interaction, resulting in nonhomogenous spread of the excitation wave front and electrical instability of the heart. Therefore cardiac nerve damage should also be taken into consideration when evaluating the effectiveness of different methods for cardiac protection.

Aortic Valve↗
PubMed1982

The resistance of glyoxylic acid induced catecholamine fluorescence to sodium borohydride reduction.

The borohydride reduction of glyoxylic acid induced fluorescence in noradrenergic and DOPA-minergic nervous structures and in amines in model experiments was studied. Both DOPAmine and noradrenaline fluorescences were resistant to borohydride reduction differing thus from the formaldehyde-induced fluorescence. Thus when the specificity of glyoxylic acid induced fluorescence is in doubt, other tests than borohydride reduction of the fluorescence must be employed.

Animals↗
PubMed1980

Barrier properties of rat subcutaneous nerves to sodium fluorescein and fluorescein-labelled dextrans of various molecular weights.

Na-fluorescein and fluorescein-labelled dextrans of various molecular weights were injected i.v. to localize the blood-peripheral nerve barrier in rat subcutaneous nerves. Samples were taken from the subcutaneous fascia and skin 5 and 30 min after the injection. In the specimens taken 5 min after the injection, the fluorescence had diffused into the dermal tissue. The intraneural, epineural, and perineural blood vessels contained fluorescent material. The entry of fluorescent material from subcutaneous tissue into the nerves was prevented by the perineurium. The distribution of the tracer was uniform throughout molecular weight range tested (376-150,000). Both dermal and intravascular fluorescence were clearly weaker in the specimens taken 30 min following the injection, particularly if a tracer with a MW lower than 40,000 was used. After bilateral ligature of the renal blood vessels the fluorescence remained more intense, even after 30 min, and it was independent of the molecular diameter of the tracer injected. The location of the fluorescence was not changed by the operation and the intraneural capillaries remained intact. The results indicate that the intraneural capillaries are impermeable to the fluorescent tracers tested. In contrast, all the marker substances passed freely through cutaneous capillaries. The perineurium prevented the diffusion of fluorescent tracers from the surrounding tissue into the nerve.

Animals↗
PubMed1980

Innervation of the human gastric wall.

The intrinsic innervation of the human gastric wall was studied by means of (1) demonstration of the acetylcholinesterase activity, (2) fluorescence microscopy, and (3) electron microscopy. The cholinergic innervation was rich: in the mucosa, a dense three dimensional network consisting of single delicate varicose acetylcholinesterase-positive axons and small nerve fascicles was observed in close relation to the gastric glands. In the submucosa, large nerve trunks and densely woven plexuses mainly consisting of single varicose axons (obviously perivascular plexuses)) were seen. In the muscularis external, a small-meshed net consisting of single varicose axons and nerve fascicles was observed. The ganglia of the myenteric plexus were small and scattered irregularly between and within the muscle layers. Most of the nerve cells exhibited moderate to intense acetylcholinesterase activity. In the serosa, only a few nerves were observed. By fluorescence microscopy, an abundance of brightly yellow fluorescing irregularly fusiform enterochromaffin cells was observed in the epithelial lining of the antral glands. The parietal cells of the fundic glands exhibited a granular, yellow to orange autofluorescence. Fluorescing axons were seen in intimate relation to some enterochromaffin cells, whereas most enterochromaffin cells and parietal cells did not receive any direct functional adrenergic innervation. In the other tissue layers, only a few fluorescing nerves were seen. The main ultrastructural characteristics of the intrinsic innervation of the mucosa were: (1) 'Innervation fasciculée'; (2) the axons were unmyelinated; (3) two main types of nerve terminals were identified according to their vesicle population(s): (a) nerve terminals containing only clear vesicles, (b) nerve terminals containing clear vesicles and large dense-cored vesicles. Most of the axons and nerve terminals within the nerve fascicles were acetylcholinesterase-positive. The nerve terminals were separated from the gastric glands (and the parietal cells, chief cells and endocrine cells of their epithelial lining) by a considerable gap so that it seems unlikely that the gastric glands, parietal cells, chief cells and endocrine cells receive a direct innervation in the sense of synaptic neurotransmission; the transmitter substance must diffuse across a wide gap. In contrast, the endocrine cells were in close contact with the parietal cells and chief cells, and occasional membrane specialization (desmosomes) reinforce the assumption that (also) direct local humoral interaction may be possible. In addition, a large number of mast cells was observed in the lamina propria, many lying as close to glandular cells (parietal cells, chief cells and endocrine cells) as were the nearest nerve terminals.

Acetylcholinesterase↗
PubMed1978

Innervation of scar tissue in the skin of the rat.

In this study the reinnervation of scar tissue was investigated histochemically to demonstrate catecholamine fluorescence and nonspecific cholinesterase activity. The scarring was produced by healing and contraction of a defect in the dorsal skin of the rat. The first regenerating nerves showing nonspecific cholinesterase activity were observed in the scar four weeks postoperatively. Throughout the investigation period, that is up to twenty weeks after the operation, only free regenerated nerves were found in the scar; no encapsulated nerve endings were observed. No fluorescent adrenergic nerves were found in the dense collagenous part of the scar tissue. Regenerated fluorescent nerves were, however, observed in the loose regenerated connective tissue under the scar. Most of these nerves followed the course of blood vessels. In the present work a vigorous contraction of the scar tissue was noted and a poor innervation of the scar tissue with free nerves was observed. The role of these regenerated nerve endings in sensory discrimination, and the importance of different transmitters acting in the sensory system are discussed.

Adrenergic Fibers↗
PubMed1977

The acetylcholinesterase reaction and catecholamine fluorescence in the glomus cells of rat carotid body.

The presence of both acetylcholinesterase reaction and glyoxylic acid-induced fluorescence of catecholamines in the same glomus cells of rat carotid body was demonstrated using combined histochemical methods. A suggestion is made that the glomus cells have both excitatory and inhibitory effects on the chemosensory nerve via acetylcholine and catecholamines, respectively.

Acetylcholinesterase↗