Biomedical subjects

A Micera

Publications and source records attributed to A Micera.

28 records · Page 2Linked to original sources

PubMed1997

Presence of nerve growth factor in the thymus of prenatal, postnatal and pregnant rats.

The presence of Nerve Growth Factor (NGF) and the expression of low- and high-affinity NGF receptor were investigated in prenatal, postnatal and pregnant rats. Using ELISA and immunohistochemistry it was found that both NGF and its receptors are present in the medulla of the thymus and are more strongly expressed in pre- and early postnatal life and nearly absent in adult and ageing rats. It was also found that during pregnancy, which is characterised by an involution of the cortex and hypertrophy of the medulla, the level of NGF in the thymus increases. The present study showed not only that NGF is produced in a specific compartment of the thymus, the medulla, but that its synthesis declines with age, following thymus involution. These results suggest that NGF may be critically involved in the proliferation and differentiation of thymic cells.

Animals↗

PubMed1996

mRNA for NGF and p75 in the central nervous system of rats affected by experimental allergic encephalomyelitis.

In this study we measured the concentration of nerve growth factor (NGF) and the expression of NGF and the low affinity NGF-receptor (NGF-r) mRNA in the central nervous system (CNS) of rats affected by experimental allergic encephalomyelitis (EAE) during the acute phase of the disease. Significant levels of NGF protein were found in thalamus and cortex on day 13 post-immunization. Molecular analysis of the NGF gene expression and of its NGF-r revealed that they were enhanced in several regions of the CNS of EAE rats when compared with untreated animals. These results suggest a functional link between local NGF synthesis and this autoimmune inflammatory disease.

Animals↗

PubMed1996

Changes in human plasma nerve growth factor level after chronic alcohol consumption and withdrawal.

Numerous studies reported in recent years have shown that withdrawal from chronic consumption of drugs induces high levels of anxiety, both in humans and in animal models. In the present study, we demonstrated that withdrawal from chronic consumption of either ethanol or heroin causes a significant increase in plasma nerve growth factor, suggesting that the resulting anxiety condition triggers the release of this molecule. Although the functional significance of this phenomenon needs to be better defined, it is hypothesized that the increased levels of circulating nerve growth factor might be involved in homeostatic adaptive and/or reparative mechanisms.

Adult↗

PubMed1996

Centrally injected nerve growth factor modulates peripheral immune responses in the rat.

The effect of the intracerebroventricular (icv) and intravenous (iv) injection of nerve growth factor (NGF) on peripheral immunity was studied in the rat. Icv administration of NGF (5, 25, 50, 250 and 500 ng/rat) significantly enhanced phytohemagglutinin (PHA)-induced splenocyte proliferation 30 min after treatment. Icv pretreatment with an anti-NGF antibody completely prevented the effect, while iv injection of anti-NGF antibody did not block the effect of icv NGF. On the contrary, NGF at doses of 0.5, 2.5, 5, 25 and 50 ng/rat decreased splenocyte natural killer (NK) activity. When injected iv, NGF enhanced splenocyte proliferation only at doses of 50 and 500 ng/rat, while it did not affect NK activity. These effects on immunity do not appear mediated by activation of the hypothalamus-pituitary-adrenal axis, since NGF did not modify plasma corticosterone concentrations at the doses used. These results indicate that NGF participates in the complex network of neuroimmune interactions.

Animals↗

PubMed1995

Effect of NGF antibodies on mast cell distribution, histamine and substance P levels in the knee joint of TNF-arthritic transgenic mice.

We have previously shown an increase in nerve growth factor (NGF) levels and in mast cell (MC) distribution in the synovium of patients affected by rheumatoid arthritis. We now report that purified NGF antibodies injected into arthritic transgenic mice carrying the human tumour necrosis factor-alpha (TNF-alpha) gene caused reduction in the number of MCs, as well as a decrease in histamine and substance P levels within the synovium. These observations suggest that NGF antibody might be useful in studying the role of these pro-inflammatory markers in joint arthritis.

Animals↗

PubMed1995

Elevated levels of nerve growth factor in the thalamus and spinal cord of rats affected by experimental allergic encephalomyelitis.

In a previous study it was shown that the levels of NGF in the cerebrospinal fluid of patients affected by multiple sclerosis (MS) increase during the acute phase of the disease and decrease in the remission phase. In the present study, using an animal model of MS, we investigate whether any changes in NGF levels occur in brains of rats affected by Experimental Allergic Encephalomyelitis (EAE). The results show an enhanced level of NGF in the thalamus and spinal cord and a numerical increase of mast cells (MCs) expressing mRNA-NGF localized in these two regions. These observations suggest that NGF is involved in EAE and that MCs contribute to the local increase of NGF.

Animals↗

PubMed1995

Increased plasma levels of nerve growth factor in vernal keratoconjunctivitis and relationship to conjunctival mast cells.

PURPOSE: To evaluate the nerve growth factor (NGF) plasma concentration in patients with vernal keratoconjunctivitis and to correlate it with the histopathology and immunopathology of the disease. METHODS: An immunoenzymatic assay was performed to measure NGF plasma levels in patients with vernal keratoconjunctivitis and in healthy matched controls. A competitive radioimmunoassay was used to detect eosinophil cationic protein (ECP) and total specific immunoglobulin E (IgE) serum levels. Histologic evaluation was performed in tarsal and bulbar conjunctival biopsies. RESULTS: Plasma levels of NGF were significantly higher (P < 0.001) in patients with vernal keratoconjunctivitis (mean = 8224.47 +/- 7802.53 pg/ml; median = 121 pg/ml) than in controls (mean = 51.68 +/- 5.94 pg/ml; median 42.5 pg/ml). Conjunctival tissue showed a significant increase of mast cells, eosinophils, and lymphocytes in vernal keratoconjunctivitis. A significant correlation was observed between plasma levels of NGF and the number of mast cells in the tarsal conjunctiva (Cc = 0.81; P < 0.005) and bulbar conjunctiva (Cc = 0.77; P < 0.01) of patients with vernal keratoconjunctivitis. No correlation was found between NGF plasma levels and total IgE serum levels in patients with vernal keratoconjunctivitis; NGF plasma levels were inversely related to the number of circulating eosinophils (Cc = -0.61; P < 0.05) and to the increased serum levels of ECP (Cc = -0.71; P < 0.02). CONCLUSIONS: These data represent the first reported evidence of increased NGF plasma levels in an allergic human disease and suggest a possible relationship between this neurotrophic polypeptide and inflammatory cells in vernal keratoconjunctivitis.

Adolescent↗

PubMed1994

Emotional stress induced by parachute jumping enhances blood nerve growth factor levels and the distribution of nerve growth factor receptors in lymphocytes.

We examined the plasma nerve growth factor (NGF) level and the distribution of NGF receptors in peripheral lymphocytes of young soldiers (mean age, 20-24 yr) experiencing the thrill of a novice about to make their first parachute jumps. Blood was collected from soldiers who knew they were selected to jump (n = 26), as well as from soldiers who knew they were not selected (n = 17, controls). The former group was sampled the evening before the jump and 20 min after landing. Compared with controls, NGF levels increased 84% in prejump and 107% in postjump sampling. Our studies also showed that the increase of NGF levels preceded the increase of plasma cortisol and adrenocorticotropic hormone. No changes in the baseline levels of circulating interleukin 1 beta or tumor necrosis factor were found, suggesting that the increased levels of NGF were not correlated with change in these cytokines. Moreover, immunofluorescence analysis demonstrated that parachuting stress enhances the distribution of low-affinity p75LNGFR and high-affinity p140trkA NGF receptors in circulating peripheral blood mononuclear cells. These observations suggest that the release of NGF might be involved in the activation of cells of the immune system and is most probably associated with homeostatic adaptive mechanisms, as previously shown for stressed rodents.

Adult↗

PubMed1993

Level of nerve growth factor and distribution of mast cells in the synovium of tumour necrosis factor transgenic arthritic mice.

We have recently reported that nerve growth factor (NGF) increases in the synovium of patients affected by arthritis, as well as in animal models. We report here that the synovium of transgenic arthritic mice expressing human tumour necrosis factor (TNF) contains numerous mast cells (MC) and that their appearance is a phenomenon which was correlated to the local increase in NGF level. These findings provide further evidence that NGF plays a role in inflammation and suggest a functional link between NGF and MC.

Animals↗

PubMedDate not supplied

Upregulation of ICAM-1 expression in the conjunctiva of patients with chronic graft-versus-host disease.

PURPOSE: To correlate conjunctival intercellular adhesion molecule 1 (ICAM-1) expression with cytologic and clinical findings of chronic graft-versus-host disease (GVHD). METHODS: Seven patients with chronic GVHD-related keratoconjunctivitis and five age-matched normal controls were recruited for the study. Clinical examination included medical history, visual acuity, evaluation of ocular signs and symptoms (scored from 0 to 3), corneal fluorescein staining (scored from 0 to 5 on the basis of the number of corneal sectors involved), Schirmer test type I, and break-up time (BUT). Impression cytology samples were collected from the nasal and inferior bulbar conjunctiva of patients and controls. Goblet cells were counted in three randomly selected fields and averaged. Immunofluorescent staining for ICAM-1 was carried out and the percentage of cells expressing the marker was evaluated. RESULTS: All patients showed signs and symptoms of keratoconjunctivitis sicca. Schirmer test type I and BUT were reduced (4.8+/-6.7 mm/5 min and 3.9+/-2.7 seconds, respectively). Goblet cells were significantly reduced in GVHD eyes with respect to normal eyes (65+/-30.5 and 192+/-16.9 cells/field respectively; p<0.001). Goblet cell number was directly related to Schirmer test values (p<0.01, rho=0.817) and inversely related to total sign score (p<0.01, rho=-0.939). ICAM-1 expression was increased in GVHD eyes with respect to normal controls, in which no staining was observed. ICAM-1 expression showed an inverse relation to goblet cell number (p<0.01, rho=-0.852) and Schirmer test values (p<0.01, rho=-0.926), and was directly correlated to total sign score (p<0.01, rho=0.982). CONCLUSIONS: Conjunctival ICAM-1 expression is increased in GVHD patients. The severity of the disease is associated with tear parameters, goblet cell decrease, and inflammatory markers, such as ICAM-1.

Adolescent↗