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Biomedical subjects

L Aloe

Publications and source records attributed to L Aloe.

229 records · Page 13Linked to original sources
PubMedDate not supplied

Prenatal exposure to ethanol causes differential effects in nerve growth factor and its receptor in the basal forebrain of preweaning and adult rats.

In this study we investigated nerve growth factor (NGF) levels in the cortex and hippocampus of the offspring of pregnant female Sprague-Dawley rats receiving a single intragastric administration of acute ethanol on the 15th day of gestation and compared them with a control group of rats that received an injection of sucrose. We also examined the distribution of the low-affinity NGF receptor, p75NGFR, on NGF-responsive neurons that are localized in the septum and the nucleus of Meynert, which receive the respective trophic support from the hippocampus and the cortex. In the ethanol-treated group, the results show that at post-natal age 15 days, the NGF septohippocampal pathways were markedly affected. At day 15, the NGF level was significantly higher in the offspring of ethanol-treated rats. By day 40, NGF values in both groups decreased to similar levels. At day 60, however, the NGF level in the ethanol-treated animals decreased to a significantly lower value than that of the control group, which remained essentially unchanged. In parallel, at day 60 the numbers of septal cholinergic neurons expressing p75NGFR were also significantly lower in ethanol-treated rats than in control animals. Because ethanol is known to induce neurological disorders, as well as deficits in cell proliferation and differentiation, the results suggest that one cause of the deleterious effects induced by ethanol is the low availability of NGF during certain stages of postnatal brain development.

Animals↗
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Nerve growth factor: an important molecule in allergic inflammation and tissue remodelling.

BACKGROUND: Several studies provide evidence that nerve growth factor (NGF) has an expanding role in neuroimmune interactions. METHODS: We review our data on circulation levels of NGF in allergic diseases as well as on the relationships between this neurotrophin and primary and secondary effector cells of allergic inflammation. RESULTS: In vernal keratoconjunctivitis, a close relationship exists between the increased NGF plasma values and the number of mast cells infiltrating the conjunctiva. NGF serum values are also increased in other allergic diseases and asthma, and are related to the severity of the inflammatory process and disease. Human CD4+ T cell clones (preferentially of activated Th2 type) produce and release NGF, and express high-affinity NGF receptors. NGF is preformed in and can act on human peripheral blood eosinophils to preferentially release inflammatory mediators. Immunoreactivity for high affinity NGF receptors is present both in basal epithelial cells and in the inflamed stroma of the allergic conjunctiva. Topical administration of NGF results in a complete healing of neurotophic corneal ulcers in man, thus suggesting a profound effect of NGF on human fibroblasts and extracellular matrix. CONCLUSION: Data presented suggest that NGF is an important molecule in allergic inflammation and tissue remodelling occurring in allergic diseases.

Animals↗
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Altered plasma nerve growth factor-like immunoreactivity and nerve growth factor-receptor expression in human old age.

BACKGROUND: Nerve growth factor (NGF), discovered because of its action on cells in the peripheral and the central nervous system, is now known to act also on immune cells in developing and adult subjects. Whether peripheral lymphocytes of aged subjects are responsive to this molecule is less clear. OBJECTIVE: Aim of our study was to investigate whether or not plasma NGF undergoes any significant changes during aging and whether or not NGF receptors on peripheral lymphocytes are affected in old subjects. METHODS: To address these questions, we used RT-PCR, immunohistochemistry, and immunoenzymatic analysis to evaluate the expression of NGF receptors in human peripheral lymphocytes and NGF-like immunoreactivity. RESULTS: These results revealed a low amount of NGF in the plasma of old subjects associated with a reduced expression of mRNA for NGF receptor trkA in peripheral lymphocytes. They also showed elevated levels of circulating interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) in the bloodstream of adult and aged subjects. CONCLUSION: Our data indicate that peripheral lymphocytes are targets for circulating NGF and suggest that changes in NGF-receptor expression on lymphocytes might be potential marker for aging lymphocytes.

Adult↗
PubMedDate not supplied

An updated role for nerve growth factor in neurobehavioural regulation of adult vertebrates.

Increasing attention has been focused on the role(s) of nerve growth factor (NGF) in neurobehavioural regulations of adult vertebrates. This interest springs from the emerging evidence that NGF is a "regulator" of physiological processes belonging to the three main homeostatic systems: the nervous, immune and endocrine systems. In fact, the spectrum of action of the NGF molecule is not restricted to neuronal cell types (central basal forebrain; peripheral sensory and sympathetic neurons) but extends also to nonneuronal cells. In mice intermale aggressive behaviour enhances serum NGF levels and promotes its synthesis in some hypothalamic areas. Other types of social events are able to cause NGF release, particularly under stress conditions. The achievement of a social role (dominant vs subordinate) is due to a functional loop involving salivary NGF release-->enhanced production of adrenal hormones-->submissive behaviour-->NGF release. In humans, plasma platelet-derived growth factor (PDGF) increases following mental stress. The aim of this review is to give an updated survey on NGF roles in neurobehavioural regulations of adult animals.

Animals↗
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Nerve growth factor serum level is reduced in patients with sensorineural hearing impairment: possible clinical implications.

Nerve growth factor (NGF) is the first and best characterised member of a family of neurotrophic factor. NGF is produced by numerous cells and it is present in physiologically relevant amounts in the bloodstream. It is known to promote the survival of peripheral sensory neurons and can be potentially useful as a therapeutic agent in neuronal system. On the both these observations we based our hypothesis that low circulating NGF might lead to sensorineural hearing loss (SNHL). To address this question we measured the levels of NGF in the bloodstream of patients affected by SNHL. The results showed that the amount of circulating NGF in these patients is significantly lower compared to levels found in patients not affected by this deficit. The results of the present study demonstrated that NGF might be a useful candidate for preventing the damage and promoting recovery or degeneration of the auditory pathways in humans.

Adolescent↗
PubMedDate not supplied

Nerve growth factor release by human synovial fibroblasts prior to and following exposure to tumor necrosis factor-alpha, interleukin-1 beta and cholecystokinin-8: the possible role of NGF in the inflammatory response.

OBJECTIVE: Aim of this study was to investigate the synthesis, release and effects of nerve growth factor (NGF) in human synovial cells isolated from synovial tissue specimen from healthy and osteoarthritis (OA) patients. METHODS: Human synovial fibroblasts cultures were established starting from healthy and osteoarthritis patients. NGF protein levels in the culture medium, NGFmRNA and high-affinity NGF receptor (Tyrosine kinase A: TrkA) expression in the cells were evaluated in basal conditions and after stimulation with pro-inflammatory cytokines or with the neuropeptide cholecystokinin-8 (CCK-8). The effect of NGF supplement to culture medium on cell proliferation, TrkA expression, and tumour necrosis factor-alpha (TNF-alpha) and inducible-nitric oxide synthase (iNOS) production was investigated. RESULTS: Under basal conditions human synovial cells produce and release NGF. Both interleukin-1-beta (IL-1 beta) and TNF-alpha, but not CCK-8 promote NGF synthesis and release from OA cells. TrkA NGF receptors are also expressed in both normal and OA synovial cells. NGF, but not IL-1 beta, TNF-alpha and CCK-8, enhances the expression of TrkA in isolated synovial cells. NGF down-regulates IL-1 beta-induced TNF-alpha and iNOS production by OA synovial fibroblasts. CONCLUSIONS: NGF is produced and released and TrkA receptors are expressed in synovial inflammation. Overexpression of NGF in inflammed joints might be involved in the modulation rather than in the induction of the joint inflammatory response.

Cells, Cultured↗
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NGF overexpression and distribution in cortical thymic epithelial cells of mice with experimentally-induced leukemia.

BACKGROUND: Thymic epithelial cells often form lymphoid-epithelial cell (LEC) complexes, thought to contribute both to normal T-cell differentiation and to leukemogenesis. The distribution of the nerve growth factor (NGF) and NGF immunoreactivity modulation of complex-forming thymus epithelial cells were studied in mice with experimental acute L1210 leukemia. MATERIALS AND METHODS: Light and electron microscopic methods and cell separation techniques were applied. RESULTS: Immunoperoxidase and immunogold labelling showed subcapsular and subseptal overexpression of NGF by epithelial cells in leukemic thymus. NGF immunopositive epithelial cells were closely associated with lymphoid cells. The increased immunoreactivity of epithelial cells correlated with LEC complex formation, including thymic nurse cell-like structures and rosettes in the external cortex. CONCLUSION: These results provide new structural and immunocytochemical evidence for intimate contact between NGF-producing epithelial cells and lymphoid cells and suggest that NGF immunoreactive LEC complexes are involved in thymic microenvironmental reorganization during leukemogenesis.

Animals↗
PubMedDate not supplied

[Anesthesia problems of patients with malignant oral neoplasms undergoing inductive chemotherapy protocol and surgery].

The Authors expand the results about thirty-nine Patients with advanced malignant tumours of the oral cavity treated with inductive chemotherapy and radical surgery. They considered the choice of a correct scheme of anaesthesia in the surgical treatment for Patients with particular health conditions and previously subjected to inductive chemotherapy. The necessity to practice a pre- and post-operative therapy for subduing the very frequent and serious concomitant diseases is underlined.

Adult↗
PubMedDate not supplied

Nerve growth factor and mast cell distribution in the skin of patients with systemic sclerosis.

Nerve growth factor (NGF), a well-characterized neurotrophic factor, induces an increase in the number of mast cells (MCs) in the peripheral tissues of developing rats, as well as histamine release in fully differentiated MCs. Since MCs increase in the dermis of patients with early systemic sclerosis (SSc), we examined the distribution of NGF in the skin of patients affected by SSc. Immunohistochemical studies showed that NGF distribution was more intense in the dermis of patients with SSc than in the skin of controls. A possible correlation between MCs and NGF in disease activity is hypothesized.

Adult↗
PubMedDate not supplied

Nerve growth factor and autoimmune rheumatic diseases.

Nerve growth factor (NGF) is the first discovered and best known neurotrophic factor and is required for the survival and differentiation of a variety of neuronal cell types in both the peripheral and central nervous system. Recent studies indicate that NGF is synthesized by cells of immune system lineage and that its level increases during inflammatory responses, while cytokines such as interleukin-1 beta and tumor necrosis factor-alpha are potent inducers of NGF secretion. The role played by NGF on cells of the immune system was strengthened by recent evidence demonstrating that cells normally present in inflammatory tissues, such as mast cells and lymphocytes, express NGF receptors and are receptive to the action of NGF. Studies carried out in our and other laboratories showed that NGF is expressed in the synovial fluid of patients with rheumatoid arthritis and other forms of chronic arthritis, as well as in the synovium of pharmacologically-induced arthritis in animal models. Moreover, arthritic transgenic mice which carry and express the human tumor necrosis factor-gene also showed elevated levels of NGF. Significant increases in NGF levels have been found in the sera of patients with systemic lupus erythematosus and in the dermis of patients affected by systemic sclerosis. In this paper the hypothesis that NGF is involved in the pathophysiology of autoimmune rheumatic arthritis is discussed.

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