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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
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↗
PubMed1977

Extended survival of pancreatic islet allografts in the testis of guinea-pigs.

1. Pancreatic islets, isolated from the guinea-pig pancreas by microdissection and transplanted as allografts to the testis, may survive for 11 weeks, some 5 times the maximum survival of orthotopic skin grafts. 2. Intratesticular islet cell allografts appear not to provoke a systemic immunity such as might be detected by the behaviour of a subsequent orthotopic skin allograft from the same donor. 3. Intratesticular islet cell allografts succumb (in 'second set' fashion) to a pre-existing immunity generated by a prior orthotopic skin allograft. 4. Further experimental work is necessary to determine the relative importance of graft dosage, graft antigenicity, graft site and 'graft adaptation' in determining this extended survival.

Animals↗
PubMed1977

Further studies on the transplantation of isolated pancreatic islets.

It is concluded that the extended survival of allografts of isolated pancreatic islets in the testis and in the omentum is probably due to several factors. 1. An element of 'privilege' in both graft sites, of unknown nature. 2. The small amount of tissue transplanted. 3. Weaker antigenicity of ancreatic islet tissue as compared with that of skin.

Animals↗
PubMed1975

The fate of heterotopic isografts and allografts of mouse yolk sac epithelium.

As a contribution to the problem of the immunological privilege of the fetus it was decided to investigate the fate of yolk sac grafts in mice. Ten-day post-coitum mouse visceral yolk sac was transplanted to a dermal tunnel in the flank of isogeneic animals. In this site the yolk sac was capable of surviving for at least 15 days past the normal duration of pregnancy. Yolk sac was transplanted to a similar site in allogeneic animals and was found to be destroyed by an immunological reaction within 13 days. Orthotopic skin grafts between the same strains of mice used in the yolk sac transplantation were rejected in first-set fashion within 13 days. A limited series of host animals, previously sensitized by visceral yolk sac, rejected orthotopic skin grafts in second-set fashion. These findings indicate that the cells of the visceral yolk sac in the mouse contain transplantation antigens. Possible reasons why such antigens do not lead to fetal rejection during pregnancy are considered.

Animals↗
PubMed1975

An electron microscopic study of the histogenesis of the parathyroid gland in the sheep.

Definitive chief cells, characterized by the presence of specific secretory granules and typical membrane configurations, were present in the developing parathyroid glands of sheep embryos from 26 days of gestation (term = 150 days). During earlier stages of gestation developing chief cells contained lysosomal systems which appeared to be concerned with the autophagy of retained secretion product. The EM evidence suggests that physiologic release of the hormone does not occur until at least 30 days of gestation, which correlates well with the experimentally established time of onset of functional capacity in the parathyroid gland in the sheep. 'Bark cells' were found in the parathyroid primordia of embryos between 20 and 27 days of gestation. The significance of these "dark cells" is discussed with respect to glutaraldehyde fixation and to their possible relationship to chief cells.

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