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Biomedical subjects

A Lambiase

Publications and source records attributed to A Lambiase.

At least 37 records · Page 2Linked to original sources
PubMed1999

Location and clonal analysis of stem cells and their differentiated progeny in the human ocular surface.

We have analyzed the proliferative and differentiation potential of human ocular keratinocytes. Holoclones, meroclones, and paraclones, previously identified in skin, constitute also the proliferative compartment of the ocular epithelium. Ocular holoclones have the expected properties of stem cells, while transient amplifying cells have variable proliferative potential. Corneal stem cells are segregated in the limbus, while conjunctival stem cells are uniformly distributed in bulbar and forniceal conjunctiva. Conjunctival keratinocytes and goblet cells derive from a common bipotent progenitor. Goblet cells were found in cultures of transient amplifying cells, suggesting that commitment for goblet cell differentiation can occur late in the life of a single conjunctival clone. We found that conjunctival keratinocytes with high proliferative capacity give rise to goblet cells at least twice in their life and, more importantly, at rather precise times of their life history, namely at 45-50 cell doublings and at approximately 15 cell doublings before senescence. Thus, the decision of conjunctival keratinocytes to differentiate into goblet cells appears to be dependent upon an intrinsic "cell doubling clock. " These data open new perspectives in the surgical treatment of severe defects of the anterior ocular surface with autologous cultured conjunctival epithelium.

3T3 Cells↗
PubMed1999

Management of neurotrophic keratopathy.

Neurotrophic keratopathy is a degenerative corneal disease caused by an impairment of corneal sensitivity. Lack of the sensory nerve's trophic effect is responsible for the impairment in corneal healing and for the changes on the ocular surface that lead to corneal epithelial deficit, ulcer, and perforation. The etiology and recent advances in understanding of the pathogenetic mechanisms of neurotrophic keratopathy are reviewed here. An accurate history and a clinical examination that covers the function of cranial nerves often identify the cause of the disease. Clinical features and guidelines for the differential diagnosis and treatment are presented. Specific medical and surgical treatments, selected on the basis of clinical staging of the disease, can often halt disease progression. Future developments in medical treatment, including the use of neuropeptide and growth factors, are discussed. The identification of corneal anesthesia associated with an epithelial defect allows appropriate treatment and prevention of progression to stromal lysis and perforation.

Cornea↗
PubMed1999

Altered nerve growth factor level in the optic nerve of patients affected by multiple sclerosis.

In this study we measured with a highly sensitive two-site immunoenzymatic assay the levels of nerve growth factor (NGF) in human optic nerve affected by multiple sclerosis (MS). The result of this study showed an elevated increase of NGF in the MS optic nerves, as compared to the level of NGF found in the optic nerves non-affected by this demyelinating disorder. Moreover, the results showed that the optic nerves also expressed trkA NGF receptor and NGFmRNA, most likely by oligodendrocytes, implying that NGF is locally produced and suggesting that the presence of NGF might be regulated by an autocrine mechanism. These and other ongoing studies on animal models indicate that altered NGF levels are among one of the early symptoms of these demyelinating diseases. The physiopathological role of NGF in the optic nerve during demyelinating disorders remains however to be defined.

Aged↗
PubMed1998

Topical treatment with nerve growth factor for corneal neurotrophic ulcers.

BACKGROUND: Corneal neurotrophic ulcers associated with impairment of sensory innervation of the cornea may lead to loss of vision, and there is no effective treatment for these ulcers. We evaluated the effects of nerve growth factor in patients with this disorder. METHODS: Twelve patients (14 eyes) with severe neurotrophic corneal ulcers associated with corneal anesthesia were treated with topical nerve growth factor 10 times daily for two days and then 6 times daily until the ulcers healed. Treatment continued for 2 weeks after the ulcers healed, and the patients were then followed for up to 12 months. The evolution of the corneal disease during treatment and follow-up was evaluated by slit-lamp examination, photography, fluorescein-dye testing, and tests of corneal sensitivity and best corrected visual acuity. RESULTS: Corneal healing began 2 to 14 days after the initiation of treatment with nerve growth factor, and all patients had complete healing of their corneal ulcers after 10 days to 6 weeks of treatment. Corneal sensitivity improved in 13 eyes, and returned to normal in 2 of the 13 eyes. Corneal integrity and sensitivity were maintained during the follow-up period (range, 3 to 12 months). Best corrected visual acuity increased progressively during treatment and follow-up in all patients. There were no systemic or local side effects of treatment. CONCLUSIONS: In this preliminary, uncontrolled study, topically applied exogenous nerve growth factor restored corneal integrity in patients with corneal neurotrophic ulcers.

Administration, Topical↗
PubMed1998

Immunophenotypic profile of peripheral blood eosinophils in acute graft-vs.-host disease.

We used a flow cytometry technique, the "FOG" method (formaldehyde and octylglucopyranoside), to investigate the expression of activation antigens, i.e., CD4, CD23, CD25, HLA-DR, and the EG2 epitope of eosinophilic cationic protein, on peripheral blood eosinophils (PBEs) in leukemic patients who had developed acute graft-vs.-host disease (aGVHD) with eosinophilia after allogeneic bone marrow transplantation (alloBMT) or leukocyte buffy coat infusion. A comparative analysis was performed in transplanted patients not affected by aGVHD and in other conditions commonly associated with peripheral eosinophilia, i.e., interleukin (IL)-2 immunotherapy and allergy. CD25, recognizing the p55 subunit of IL-2 receptor, was detected in all patients with aGVHD except two who, at the onset of eosinophilia, were already receiving methylprednisolone intravenously. The specificity of our findings is confirmed by the absence of reactivity with anti-CD25 mAb in PBEs from transplanted patients not affected by aGVHD. Interestingly, the expression of CD25 progressively declined after steroid therapy. CD25 was also expressed after rhIL-2 administration, probably reflecting analogous mechanisms of eosinophil activation. No aGVHD or rhIL-2-treated patient showed reactivity with anti-CD4, CD23, or HLA-DR. CD25 and CD23 antigens were detected in 29% and 36% of allergic patients only. The accessibility of the EG2 epitope was significantly enhanced in all study groups compared with controls. In vitro activation of normal eosinophils with phorbol 12-myristate 13-acetate upregulated CD9 and EG2 expression but failed to induce the CD25 antigen, suggesting that selective activating stimuli may be required. The functional significance of in vivo CD25 expression and the role of activated PBEs in the development of cellular and cytokine-mediated tissue destructive processes in aGVHD remain to be clarified.

Adolescent↗
PubMed1998

Expression of nerve growth factor receptors on the ocular surface in healthy subjects and during manifestation of inflammatory diseases.

PURPOSE: Recent studies have suggested the involvement of nerve growth factor (NGF) in the conjunctival inflammatory process and in corneal epithelium proliferation and differentiation. To verify the hypothesis that NGF could locally modulate the inflammatory and reparative processes, the authors evaluated the expression of NGF high-affinity receptor on the ocular surface in normal and pathologic conditions. METHODS: Ten conjunctival biopsies (obtained from three healthy subjects, five patients affected by vernal keratoconjunctivitis [VKC], and two patients with cicatricial pemphigoid [CP]) and five corneal specimens obtained from the Eye Bank of Veneto (Italy) were evaluated. All specimens were histologically stained, and immunohistochemistry was performed to identify the NGF high-affinity receptor (TrkA). RESULTS: All tissues expressed immunoreactivity for NGF receptors. In conjunctival specimens of healthy subjects, basal epithelial cells strongly expressed immunoreactivity and, in the stroma, rare cells were immunopositive for TrkA. No significant difference in immunoreactivity was observed in the conjunctival epithelium between healthy subjects and patients with inflammatory conjunctival diseases, whereas there were more immunopositive cells observed in the conjunctival stroma of VKC and CP patients than in the controls. The immunoreactivity in the cornea was confined to basal epithelial cells and endothelium. CONCLUSIONS: The NGF receptor is present on the human ocular surface. The authors' data support the possibility that NGF modulates ocular inflammation and corneal epithelial proliferation and differentiation through its receptors.

Adolescent↗
PubMed1997

Nerve growth factor (NGF) reduces and NGF antibody exacerbates retinal damage induced in rabbit by experimental ocular hypertension.

BACKGROUND: It has been shown that intravitreal injection of NGF inhibits ganglion cell degeneration after optic nerve transection and ischemic injury. The aim of our study was to investigate the presence of NGF in aqueous humor and its involvement in retinal damage during ocular hypertension. METHODS: We used an experimental model of ocular hypertension in rabbit. Before treatment and 4, 10 and 15 days after induction of hypertension, we evaluated histological retinal damage and NGF levels in aqueous humor using an immunoenzymatic assay. Polyclonal anti-NGF antibodies were injected intravitreally into one eye of each rabbit (n = 6), and the animals were killed after 4 days of hypertension. Another group of rabbits (n = 12) was injected retro-ocularly with NGF and killed after 10 or 15 days of treatment for histologic evaluation of the retina. RESULTS: Our data show that experimental ocular hypertension in adult rabbits induces retinal damage and enhances local NGF levels. The highest NGF value was found after 4 days of intraocular hypertension: high levels persisted, though to a lesser extent, for up to 15 days. Histological examination revealed that the number of retinal ganglion cells (RGC) remained unchanged during the first 4 days but decreased at 10 days. These studies also showed that retro-ocular administration of NGF reduced RGC loss, whereas intraocular injection of NGF antibodies, which inhibited the endogenous NGF, exacerbated the retinal insult. CONCLUSION: These findings demonstrate a protective effect of NGF on RGC damaged by ocular hypertension and prompt further investigations to evaluate a possible therapeutic use of NGF to retard RGC death in humans.

Animals↗
PubMed1997

Human CD4+ T cell clones produce and release nerve growth factor and express high-affinity nerve growth factor receptors.

BACKGROUND: Increasing evidence shows that nerve growth factor (NGF) plays a role in the complex and fascinating linkage between the nervous and the immune systems due to its ability to modulate functions of several inflammatory cells. OBJECTIVE: To investigate NGF receptor expression and NGF production and release by human CD4+ cells clones, which have primary relevance in modulating inflammatory events through their different subsets of functional phenotypes. METHODS: The expression of NGF and a transmembrane tyrosine kinase (TrkA) was evaluated by immunohistochemistry and flow cytometry analysis in five T(H0), six T(H1), and five T(H2) cell clones derived from human circulating mononuclear blood cells. Moreover, the amount of NGF protein was assessed by measuring the NGF levels in culture supernatants of the T cell clones before stimulation and 48 hours after phytohemagglutinin (PHA) activation by use of an immunoenzymatic assay. RESULTS: Our data have shown that in unstimulated conditions, human CD4+ T cell clones express both immunoreactivity for NGF and the TrkA NGF receptor irrespective of their cytokine profile. Moreover, T(H1) and T(H2) clones, but not T(H0) clones, secrete NGF in basal conditions. PHA activation induces NGF secretion in T(H0) clones and a significant increase of NGF levels in T(H2) (p < 0.05), but not in T(H1) culture supernatants. CONCLUSIONS: Results obtained represent the first evidence of TrkA expression and NGF production and release in human CD4+ cell clones and suggest a possible functional role of NGF in modulating the immune and inflammatory network.

CD4-Positive T-Lymphocytes↗
PubMed1997

Efficacy of lodoxamide eye drops on mast cells and eosinophils after allergen challenge in allergic conjunctivitis.

PURPOSE: The purpose of the study is to evaluate in a double-blind, randomized study the efficacy of lodoxamide tromethamine 0.1% versus placebo. METHODS: Signs and symptoms, tear tryptase, and tear fluid cytology were evaluated in 20 asymptomatic subjects with allergic conjunctivitis. The study included three allergen challenges in skin test-positive patients. At the first visit, a threshold dose of allergen was established. At the second visit, a bilateral ocular challenge was performed without pretreatment. At the third visit, either lodoxamide or placebo eye drops were used for 1 week before ocular challenge. RESULTS: Lodoxamide significantly reduced tryptase levels (P < 0.01), neutrophils (P < 0.04), and eosinophils (P < 0.01) in the tear fluid and significantly inhibited ocular itching (P < 0.02) when compared with that of placebo. CONCLUSIONS: Lodoxamide is effective in reducing tryptase levels and the recruitment of inflammatory cells in the tear fluid after allergen challenge.

Administration, Topical↗
PubMed1997

The eosinophil and the eye.

Personal studies in allergic eye diseases reviewed in this paper indicate that: 1. An increased number and an abnormal distribution of eosinophils is present in conjunctival biopsies of patients with vernal keratoconjunctivitis (VKC). 2. Eosinophil and eosinophil products, such as ECP, are also increased in tears of VKC patients and, in hay fever conjunctivitis, accumulate during the late-phase of allergic reaction following specific allergen challenge. 3. Circulating eosinophils of VKC patients show a typical activation phenotypic profile which is associated with increased serum level of eosinophil cationic protein and eosinophil-derived neurotoxin/protein X. A clinical study of the modulatory effect of cetirizine on the early and late phase of the allergic reaction as well as on the eosinophil activation and tissue recruitment following conjunctival allergen challenge is reported as an example of the need to evaluate eosinophil functions when investigating anti-allergic drugs. Drugs modulating various aspects of eosinophil function could play a primary role in the treatment of allergic eye disease.

Cetirizine↗
PubMed1997

Increased plasma levels of substance P in vernal keratoconjunctivitis.

PURPOSE: The increase of nerve growth factor (NGF) plasma levels in vernal keratoconjunctivitis (VKC) patients has been demonstrated previously. Results of numerous studies in vitro and in vivo have shown that NGF modulates the synthesis of substance P (SP), a neuropeptide involved in the pathogenesis of human allergic diseases. In this study the involvement of SP in this allergic conjunctivitis is investigated, along with its relationship with NGF and other systemic and local markers of VKC. METHODS: Competitive radioimmunoassays were used to detect the levels of SP in plasma, the levels of eosinophil cationic protein, and the total and specific immunoglobulin E in the serum of 11 patients with VKC and in 11 healthy matched controls. Plasma levels of nerve growth factor (NGF) were measured in all VKC patients and controls using an immunoenzymatic assay. Histologic evaluation was performed in tarsal and bulbar conjunctival specimens obtained in biopsies from 8 VKC patients and 4 control subjects. RESULTS: Patients with VKC show a significant increase of SP and NGF plasma levels (P < 0.003 and P < 0.001, respectively), and an increase of eosinophil cationic protein and immunoglobulin E levels in the serum (P < 0.001 and P < 0.002, respectively). Mast cells, eosinophils, and lymphocytes were also significantly increased in the conjunctiva of VKC patients. Interestingly enough, VKC patients with the highest NGF plasma levels also showed the highest SP levels. CONCLUSIONS: The data show the involvement of SP in VKC and suggest that SP with NGF could modulate the allergic response in this disease, probably through an interaction with inflammatory cytokines.

Adolescent↗
PubMed1996

Circulating nerve growth factor levels are increased in humans with allergic diseases and asthma.

Nerve growth factor (NGF) serum levels were measured in 49 patients with asthma and/or rhinoconjunctivitis and/or urticaria-angioedema. Clinical and biochemical parameters, such as bronchial reactivity, total and specific serum IgE levels, and circulating eosinophil cationic protein levels, were evaluated in relation to NGF values in asthma patients. NGF was significantly increased in the 42 allergic (skin-test- or radioallergosorbent-test-positive) subjects (49.7 +/- 28.8 pg/ml) versus the 18 matched controls (3.8 +/- 1.7 pg/ml; P < 0.001). NGF levels in allergic patients with asthma, rhinoconjunctivitis, and urticaria-angioedema were 132.1 +/- 90.8, 17.6 +/- 6.1, and 7.6 +/- 1.8 pg/ml (P < 0.001, P < 0.002, and P < 0.05 versus controls), respectively. Patients with more than one allergic disease had higher NGF serum values than those with a single disease. When asthma patients were considered as a group, NGF serum values (87.6 +/- 59.8 pg/ml) were still significantly higher than those of control groups (P < 0.001), but allergic asthma patients had elevated NGF serum levels compared with nonallergic asthma patients (132.1 +/- 90.8 versus 4.9 +/- 2.9 pg/ml; P < 0.001). NGF serum levels correlate to total IgE serum values (rho = 0.43; P < 0.02). The highest NGF values were found in patients with severe allergic asthma, a high degree of bronchial hyperreactivity, and high total IgE and eosinophil cationic protein serum levels. This study represents the first observation (that we know of) that NGF is increased in human allergic inflammatory diseases and asthma.

Adolescent↗
PubMed1996

Nerve growth factor delays retinal degeneration in C3H mice.

BACKGROUND: The aim of the present study was to investigate the biological role of nerve growth factor (NGF) on retinal degeneration in the C3H mouse strain. This strain is characterized by a single gene mutation (rd) which leads to photoreceptor degeneration resembling human retinitis pigmentosa. METHODS: Neural retinas from 1- to 25 day-old C3H mice were dissected from outer ocular tissues, dissociated in cell suspension, stained with a vital dye and counted in a hemocytometer. For in vivo study, NGF was injected into the intraocular or retro-ocular area, and at the end of the treatment the mice were killed. The eyes were enucleated, fixed and cut by cryostat into 14-microns serial sections. The serial sections were stained with hematoxylin-eosin and the outer nuclear layer (ONL) was measured using a computerized image analysis system. RESULTS: An intraocular injection of NGF, or repeated retro-ocular injections, induced a significant increase in ONL thickness compared to controls. CONCLUSION: Our data show that NGF inhibits retinal degeneration in C3H mice. The mechanism(s) underlying the protective action of NGF against retinal cell death remains to be established.

Animals↗
PubMed1996

Histopathological evaluation of retinal damage during intraocular hypertension in rabbit: involvement of ganglion cells and nerve fiber layer.

BACKGROUND: Current clinical tests do not detect glaucomatous signs until the onset of substantial retinal damage. Therefore animal models are required to investigate the very early histopathological alterations in glaucoma disease. We used an experimental model of intraocular hypertension to compare early changes in retinal ganglion cell (RGC) density with the thickness of the nerve fiber layer (NFL). METHODS: Methylcellulose 2% was injected into the anterior chamber of 18 eyes of 18 New Zealand albino rabbits. Intraocular pressure was measured 6 h after the injection and thenceforth once a day using a Shiötz tonometer. Histopathological analysis was performed on days 4, 10, and 15 following the induction of hypertension (six eyes for each group). Sections from the upper temporal retina were stained with hematoxylin-eosin and immunohistochemically using a polyclonal antibody PGP 9.5 to identify RGC. An image analysis system was used to evaluate the RGC and the thickness of the NFL. RESULTS: We observed a significant increase in intraocular pressure until the end of the experiment. Histological analysis showed, after 10 days of ocular hypertension, a significant decrease in RGC density (P < 0.05) and a significant increase (P < 0.05) in glial cell density. We found a significant correlation between RGC loss and cell area at 4 days (P < 0.01; Cc = 0.86) and at 10 days (P < 0.002; Cc = 0.91) of intraocular hypertension. We did not observe a significant decrease in the NFL thickness until 10 days of intraocular hypertension. CONCLUSIONS: Our study confirms the size-dependent RGC loss during intraocular hypertension and shows no early decrease in NFL thickness.

Animals↗
PubMed1996

Efficacy of mipragoside ophthalmic gel in vernal keratoconjunctivitis.

To evaluate the efficacy of Mipragoside, a ganglioside derivative, in vernal keratoconjunctivitis we performed a controlled randomised clinical trial involving 24 patients (mean age 10 +/- 3.4 years, range 5-20 years). Patients received either Mipragoside 0.5% aqueous ophthalmic gel or placebo four times a day for 2 weeks after a week of treatment with placebo. Ocular signs and symptoms were evaluated and considered for statistical analysis. Results show that Mipragoside significantly reduces all symptoms, being most effective on itching (p = 0.01; p = 0.0001) and hyperaemia (p = 0.01; p = 0.0006) after 1 and 2 weeks respectively when compared with placebo. Physician judgement of drug efficacy at the end of treatment was significantly in favour of Mipragoside (p = 0.0001) compared with placebo. We conclude that Mipragoside topical treatment improves symptoms of patients with vernal keratoconjunctivitis and we postulate a possible anti-inflammatory activity of this compound.

Administration, Topical↗