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Biomedical subjects

R J Scothorne

Publications and source records attributed to R J Scothorne.

At least 19 recordsLinked to original sources
PubMed1998

Behavior of radial forearm skin flaps transplanted into the oral cavity.

Radial forearm skin flaps transplanted into the oral cavity in patients undergoing treatment for intra-oral tumors frequently acquire a gross appearance resembling that of buccal mucosa. This article reports studies of biopsies of the flaps in 53 patients, of which 21 showed changes at some stage in the follow-up period. The project aims to determine whether 1) the change in the epithelium to a mucosal form is genuine or reactive, 2) a creeping replacement of epidermis results from the surrounding buccal epithelium, 3) alterations in the epidermis could be associated with changes in the dermis, 4) the change is caused by radiotherapy. Examination of the biopsies by resin histology and transmission electron microscopy shows that the changes may be reversible: it suggests that they are reactive in nature, and related to the degree of dermal inflammation, rather than to the effect of radiotherapy. The dermis persists as such and is not replaced by buccal lamina propria.

Adult↗
PubMed1997

Cell death in the developing chick knee joint: I. Spatial and temporal patterns.

The occurrence, distribution and nature of cell death has been studied in the interzone of the developing knee joint of the chick by optical, transmission and scanning electron microscopy. Cell death precedes and accompanies the process of formation of the joint cavity (apart from the femoropatellar component), and is also associated with the surfaces of intra-articular structures as they differentiate within the interzone. Cell death in the knee joint shows many of the morphological characteristics of apoptosis. It is proposed that cell death is one factor in the process of cavity formation in the joint.

Animals↗
PubMed1996

Studies on haemolymph nodes. IV. Comparison of the route of entry of carbon particles into parathymic nodes after intravenous and intraperitoneal injection.

Haemolymph nodes are found in certain mammals including man. In the rat they are located near the kidneys, spleen and thymus. A distinctive feature is that their sinuses contain numerous erythrocytes. For renal and splenic haemolymph nodes, the erythrocytes appear to be extrinsic in origin, entering the node via its afferent lymphatics (Hogg et al. 1982; Abbas et al. 1983). In the present study we investigated the drainage of carbon particles injected intraperitoneally or intravenously into the parathymic haemolymph nodes. Carbon particles injected intraperitoneally reached the nodes rapidly, within minutes and in large quantities, via the afferent lymphatics draining principally from the diaphragmatic peritoneum. Carbon particles injected intravenously entered the nodes much more slowly, reaching a maximum after 5-7 d, and in much smaller amounts, although the pattern of distribution was similar, spreading from the subcapsular sinus into the intermediate and medullary sinuses. No carbon particles were found crossing the walls of high endothelial venules. Carbon particles injected intravenously reach the parathymic nodes from peripheral lymph via the afferent lymphatics. Whilst accepting that there are significant biological differences between carbon particles and erythrocytes it seem possible that erythrocytes, like injected carbon particles, may enter the nodes by a similar route.

Animals↗
PubMed1991

The response of the regional lymph node to epididymal sperm granulomas after vasectomy.

The cause of the variable immune response in the regional testicular lymph node of inbred Albino Swiss rats after vasectomy was investigated in two experiments. In the first, the ductus deferens was transected at its junction with the epididymis so that, in every case, sperm granulomas developed in the epididymis, from which lymph is known to drain invariably to the testicular node. In spite of this, not all testicular nodes showed histological signs of an immune response at 12 weeks after vasectomy. In the second experiment the contents of epididymal lymphatics were compared in vasectomised rats and sham-operated controls at intervals of up to 18 months after operation. Lymphatics in animals with an 'active' epididymal granuloma invariably contained numbers of macrophages and lymphocytes, thought to be involved in antigen transport, while those of controls contained none. It is concluded that variations in the lymphatic drainage of vasal granulomas were not primarily responsible for the variable lymph node response to vasectomy previously reported.

Animals↗
PubMed1990

Variation in the response of chick embryos to incision of the roof plate of the neural tube at different developmental stages.

The effects of microsurgical reopening of the neural tube were examined in chick embryos of Stages 12-18. The roof plate of the thoracic neural tube was incised for a length equivalent to 7 somites. The site of incision was studied histologically and by SEM and TEM at intervals up to 48 hours. 48 hours after operation, persistent neural tube defects were more frequent and longer in embryos of more advanced stages at operation. Exposure of embryos to Streptomyces hyaluronidase, which inhibits neurulation in normal embryos, has no effect on the healing of the incised neural tube in the young embryos. Healing of the lesion in younger embryos appeared to occur in two stages: initially, by repair of the surface ectoderm, by a cephalo-caudal zipper-like mechanism, followed by a reconstitution of the roof plate by migration of neurectodermal cells on the deep surface of the ectoderm. Neural tubes of older embryos splay open more widely on incision of the roof plate, apparently making healing mechanically more difficult. This wider splaying may be related to the decline of forces which maintain occlusion of the neural canal in younger embryos.

Animals↗
PubMed1988

The lymphatic drainage of the epididymis and of the ductus deferens of the rat, with reference to the immune response to vasectomy.

The lymphatic drainage of the testis, epididymis and ductus deferens was determined in unoperated and in unilaterally vasectomised Albino Swiss rats. In the vasectomised animals, the lymphatic drainage of epididymal and vasal sperm granulomas was also investigated. The normal epididymis, and sperm granulomas which develop in it after vasectomy, drain to the regional testicular lymph node via the inferior epididymal trunk; vasectomy does not interfere with this route. There is a lymphatic watershed within the middle one third of the scrotal ductus deferens; lymph may drain caudally, to enter the inferior epididymal trunk and/or rostrally to the iliac node. Lymphatics draining granulomas at the vasectomy site, may, therefore, be interrupted by vasectomy. This would contribute to, but does not fully explain, the variable immune response of the regional testicular node following vasectomy.

Animals↗
PubMed1988

A quantitative study of the effects of vasectomy on spermatogenesis in rats.

A large sample of cross sectional profiles of seminiferous tubules from the left testes of five Albino Swiss rats 6 months after left unilateral vasectomy was compared with those of sham-operated controls. Using the classification of Leblond & Clermont (1952), based primarily on the morphology of the spermatids, the frequency of each stage of the seminiferous cycle was recorded. Profiles were also analysed for distension, reduction in epithelial area and changes in spermatocyte numbers. The lack of significant alterations in either the seminiferous cycle, the numbers of pachytene spermatocyte nuclei or epithelial area in the tubular profiles indicated that there was no alteration in spermatogenic rate after vasectomy. The lack of tubular distension, reduction in spermatocytes per unit length of perimeter or of the presence of mature spermatozoa at inappropriate stages of the cycle indicated the absence of sperm retention. The study makes clear that, at least in Albino Swiss rats 6 months after vasectomy, the apparently healthy tubules were indeed normal.

Animals↗
PubMed1987

On the mode of sperm autoantigen presentation to the regional lymph node of the testis after vasectomy in rats.

The regional testicular lymph nodes of vasectomised rats, and of sham-operated controls, have been examined, in stained smears of cell suspensions, for the presence of spermatozoa, at intervals of 1-10 weeks after operation. Very few, if any, spermatozoa were found in either group. These findings differ from those reported in rams and boars by Ball & Setchell (1983), and indicate species differences in the mode of presentation of sperm autoantigens to the regional nodes after vasectomy.

Animals↗
PubMed1986

On the response of the regional testicular lymph nodes after unilateral vasectomy in rats.

The histological response of the regional testicular lymph node has been studied at intervals from 1-12 weeks after unilateral vasectomy in rats. The criteria of a humoral immune response were increase in volume of the node, of number and size of germinal centres and of thickness and cellularity of medullary cords. Histological evidence of an immune response was delayed and variable, in conformity with serological data. Variability in the lymphatic drainage of the testis and epididymis has not been finally excluded as a cause of this variation in response. Variability of response did not seem to correlate with variation in site and size of the sperm granuloma, which is thought to be the principal site of leakage of sperm antigens.

Animals↗
PubMed1985

Electron microscopic morphometric studies on the resting and secreting nasal (salt) glands of the domestic duck. I. Standardisation of the fixation procedure.

In order to perform morphometric analysis of the nasal (salt) glands of domestic duck it was necessary to standardise the regime of fixation and processing for this tissue. This paper reports the results of these experiments in which the nasal glands of nine groups of ducks were perfused by fixatives containing various concentrations of glutaraldehyde; each group included three secreting ducks and three non-secreting control ducks. Fixative osmolality ranged from 300-825 m-osmol. The resulting effects on the electron microscopical appearances of mitochondria and intercellular spaces were assessed. The fixative finally selected as most satisfactory for both control and secreting tissue contained 3.5% glutaraldehyde and 3% dextran in sodium cacodylate buffer, giving an osmolality range of 580-650 m-osmol.

Animals↗
PubMed1982

Studies on hemolymph nodes. I. Histology of the renal hemolymph node of the rat.

The structure of the left renal hemolymph node of young adult male Swiss albino rats has been studied by optical microscopy of semithin plastic embedded sections. Afferent lymphatics were found, opening into the subcapsular sinus through valved ostia, in a large majority of nodes. Free erythrocytes were found in the afferent lymphatics and in the subcapsular sinus. In the intermediary and medullary sinuses, erythrocytes were mostly attached to sinus macrophages. The efferent lymphatics contained few erythrocytes. All the sinuses macrophages. The efferent lymphatics contained few erythrocytes. All the sinuses contained a stained precipitate of lymph protein. The node is hypoactive in its general form but does not differ essentially from typical lymph nodes, except that it receives, through its afferent lymphatics, lymph containing numerous erythrocytes.

Animals↗
PubMed1982

Studies on hemolymph nodes. III. Renal lymph as a major source of erythrocytes in the renal hemolymph node of rats.

The content of erythrocytes in the intrinsic lymphatics of the kidneys of young adult male Swiss-Albino rats was studied by optical and transmission electron microscopy, in material fixed by vascular perfusion. Erythrocytes were consistently found in lymphatics associated with interlobular, arcuate, interlobar and hilar arteries. They are presumed to have entered lymphatics by diapedesis through peritubular capillaries and veins with which they are frequently in intimate contact. The findings confirm the view that, in the rat, the kidney is an important source of the erythrocytes found in the renal hemolymph node.

Animals↗
PubMed1980

Do vascular clones determine developmental patterns?

It is postulated that endothelial (and possibly other) cells are arranged in monoclonal zones, each of which occupies an accurately predetermined site in the cardiovascular system. The clones impose detailed developmental patterns on the vascular tree itself and provide positional information relevant to the morphogenesis of surrounding tissues--for example, clones in the dermis regulate the behaviour of epidermal melanocytes.

Cardiovascular System↗