Regeneration of neural lobe-like neurovascular contact regions in explanted neural lobes placed in the hypothalamo-neurohypophysial tract in the lateral retrochiasmatic area

Carithers, Jeanine; Hd, Dellmann

doi:10.1016/0006-8993(92)91659-3

Cited by 7 publications

(6 citation statements)

References 26 publications

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“…However, there are results suggesting that very little axonal regeneration occurs at the lesion site, when transection of the axons are performed within the hypothalamus (Danilova and Polenov, 1977;Scott and Knigge, 198 1;Nagy et al, 1983;Dellman et al, 1987;Dellman and Carithers, 1992). These results have led to the idea that fibers and terminals from magnocellular cells need a special microenvironment in order to regenerate after lesion, and this may be in part provided by fenestrated blood vessels and pituicytes (Dellman et al, 1988;Carithers and Dellman, 1992;Dellman and Carithers, 1992). In this way, it has been hypothesized that a so far unknown trophic factor(s) could promote regenerative processes (Dellman and Carithers, 1992).…”

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confidence: 99%

Reorganization of neural peptidergic systems in the median eminence after hypophysectomy

Meister

Hökfelt

1994

J. Neurosci.

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Earlier studies have shown the formation of a novel neural lobe after hypophysectomy, an experimental manipulation that causes transection of neurohypophyseal nerve fibers and removal of pituitary hormones. The mechanisms that underly this regenerative process are poorly understood. The localization and number of peptide-immunoreactive (-IR) fibers in the median eminence were studied in normal rats and in rats at different times of survival after hypophysectomy using indirect immunofluorescence histochemistry. The number of vasopressin (VP)-IR fibers increased in the external layer of the median eminence in 5 d hypophysectomized rats. Oxytocin (OXY)-IR fibers decreased in the internal layer and progressively extended into the external layer. At long survival times (9 and 16 months) both VP- and OXY-IR fibers had a bilayered distribution occupying both the external and internal layers. Double-labeling experiments combining VP and tyrosine hydroxylase antisera as well as OXY and growth hormone-releasing factor antisera showed that injured neurosecretory fibers growing into the external layer displaced fibers from parvocellular cells originally located there. As a result, there was essentially an inversion in the distribution of these fibers within the median eminence. Galanin (GAL)- and cholecystokinin (CCK)-IR fibers exhibited a similar pattern of distribution after the lesion. Thus, after 5 d there was an increase in GAL- and CCK-IR fibers in the internal layer. At 14 and 30 d, the number of GAL- and CCK-IR fibers progressively decreased, but after longer survivals (9 and 16 months) there was a dramatic reappearance. Dynorphin (DYN)-LI showed a dramatic increase at all levels of the median eminence at short survival times after hypophysectomy, followed by a subsequent decrease to a final stage of a few, strongly immunoreactive fibers in the external layer at longer survival times. Vasoactive intestinal polypeptide (VIP)- and peptide histidine-isoleucine (PHI)-IR fibers in hypophysectomized animals had already contacted portal vessels 5 d after hypophysectomy, and from then on progressively increased in numbers. Finally, most of the peptide fibers described above formed dense innervation patterns around the large blood vessels along the lateral borders of the median eminence. The present results show that hypophysectomy induces a wide variety of changes in hypothalamic neurosecretory fibers. Not only is the expression of several peptides in these fibers modified following different survival times, but a reorganization of the distribution of immunoreactive fibers within the median eminence is demonstrated. The hypothesis is raised that regeneration of injured neurosecretory fibers may be dependent on changes in the expression of peptides possessing trophic actions.

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confidence: 99%

Reorganization of neural peptidergic systems in the median eminence after hypophysectomy

Meister

Hökfelt

1994

J. Neurosci.

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“…In fact, the most densely vascularized grafts (neural lobes) contained the largest numbers of neurosecretory axons, while grafts with the fewest number of capillaries (optic nerves) sustained considerably fewer regenerating neurosecretory axons (Dellmann et al, 1985). The role of viable glial cells for sustaining neurosecretory axon regeneration was recently substantiated in a study using intrahypothalamically cryotreated neural lobe expiants (Carithers and Dellmann, 1992). Virtually no neurosecretory axon regeneration was observed into the transplanted neural lobe expiants up to 15 days posttransection and grafting.…”

Section: Regeneration In the Mammalian Cnsmentioning

confidence: 99%

“…Virtually no neurosecretory axon regeneration was observed into the transplanted neural lobe expiants up to 15 days posttransection and grafting. It was hypothesized that the absence of pituicytes is responsible for this lack of neurosecretory axon regeneration (Carithers and Dellmann, 1992). When neural lobes are explanted, however, only a few capillaries survive, and those that do gradually lose their fenestrae over time (Dellmann et al, 1991).…”

Section: Regeneration In the Mammalian Cnsmentioning

confidence: 99%

“…This alignment may be induced by pituicytes or pituicyte secretions. The lack of neurosecretory axon regeneration into intrahypothalamic grafts of neural lobe in which pituicytes had been killed by cryotreatment (Carithers and Dellmann, 1992) (Ide et al, 1983;Hopkins et al, 1985;Berry et al, 1986;Bunge et al, 1988). The peripheral nerve microenvironment, when grafted into the CNS, also supports axonal regeneration (Benefey et al, 1982;Aguayo et al, 1982Aguayo et al, , 1983Aguayo, 1985;Aguayo, 1981, 1985;Mitchell et al, 1985), including that of neurosecretory axons (Dellmann et al, 1986;present study).…”

Section: Role Of Glial Cellsmentioning

confidence: 99%

“…Intrahypothalamic grafts in which the glial cells were killed by cryotreatment and the basal laminae were preserved were shown to be poor substrate for neurosecretory axon regeneration (Dellmann and Carithers, 1992a;Carithers and Dellmann, 1992).…”

Section: Extracellular Matrixmentioning

confidence: 99%

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Regeneration of neurosecretory axons into intrahypothalamic grafts of neural lobe, sciatic nerve, and optic nerve: a neurophysin-immunohistochemical, HRP-histochemical, and fine structural study

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Artificial neural networks for cancer research: Outcome prediction

Burke

1994

Seminars in Surgical Oncology

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The use of artificial neural networks in biological and medical research has increased tremendously in the last few years. Artificial neural networks are being used in cancer research for image processing, the analysis of laboratory data for breast cancer diagnosis, the discovery of chemotherapeutic agents, and for cancer outcome prediction. A neural network generalizes from the input data to patterns inherent in the data, and its uses these patterns to make predictions or to classify. This paper explains how neural networks work, and it shows that a neural network is more accurate at predicting breast cancer patient outcome than the current staging system.

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Regeneration of neural lobe-like neurovascular contact regions in explanted neural lobes placed in the hypothalamo-neurohypophysial tract in the lateral retrochiasmatic area

Cited by 7 publications

References 26 publications

Reorganization of neural peptidergic systems in the median eminence after hypophysectomy

Reorganization of neural peptidergic systems in the median eminence after hypophysectomy

Regeneration of neurosecretory axons into intrahypothalamic grafts of neural lobe, sciatic nerve, and optic nerve: a neurophysin-immunohistochemical, HRP-histochemical, and fine structural study

Artificial neural networks for cancer research: Outcome prediction

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