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Biomedical subjects

A Del Prete

Publications and source records attributed to A Del Prete.

At least 19 recordsLinked to original sources
PubMed2001

Anti-Fas (CD95/Apo-I) autoantibodies and soluble Fas levels concur in T cell depletion in HIV type 1 infection.

Deregulation of the Fas/FasL pathway in activated T cells is suspected to contribute to the abnormal apoptosis that drives their progressive depletion during HIV-1 infection. However, the role of serum soluble Fas (sFas) is unclear. Here we investigated both sFas and anti-Fas IgG levels in a cohort of 227 HIV-1-infected patients with respect to their T cell apoptosis. By using optimized ELISAs, we found that serum titers of sFas and anti-Fas were linearly correlated in 17 severely lymphopenic subjects as compared with other patients grouped in relation to their single expression of anti-Fas and sFas, or with double-negative control patients. Cytofluorimetric measurement of the subdiploid DNA-containing cell population by both PI and TUNEL revealed an increased occurrence of cell death in vitro, in particular in patients with elevations of sFas. We also found that fresh CD4(+) cells from these patients showed high levels of both caspase 3 (CPP32) and its molecular targets, namely PARP and CK18. In addition, their in vitro proliferative rate was inhibited by sFas, in particular in patients with undetectable levels of the soluble receptor in vivo as well as in normal donors. In these subjects the Fas-related caspase 8 (FLICE) was significantly increased in cells treated with the recombinant Fas. These results support the contention that functionally exhausted T cells may undergo apoptosis in response to the persistent in vivo stimulation by sFas. This may elucidate the described occurrence of enhanced cell death in advanced HIV-1 infection in association with serum elevations of the soluble receptor.

Antibodies, Monoclonal↗
PubMed2001

Dendritic cells as a major source of macrophage-derived chemokine/CCL22 in vitro and in vivo.

Macrophage-derived chemokine (MDC)/CCL22 is a CC chemokine active on dendritic cells (DC), NK cells and Th2 lymphocytes. The present study was aimed at comprehensively investigating MDC production in vitro and in vivo. DC were the most potent producers of MDC among leukocytes tested. Endothelial cells did not produce MDC under a variety of conditions. Signals that induce maturation (lipopolysaccharide, IL-1, TNF, CD40 ligand, recognition of bacteria and yeast) dramatically augmented MDC production, and dexamethasone and vitamin D3 blocked it. Prostaglandin E(2), which blocked the acquisition of IL-12 production and the capacity to promote Th1 generation, did not affect MDC production. Using mass spectrometry-based techniques, DC supernatants were found to contain N-terminally truncated forms of MDC [MDC(3-69), MDC(5-69) and MD(C7-69)] as well as the full-length molecule. In vivo, CD1a(+), CD83(+), MDC(+) DC were found in reactive lymph nodes, and in Langerhans' cell histiocytosis. Skin lesions of atopic dermatitis patients showed that CD1a(+) or CD1b(+) DC, and DC with a CD83(+) phenotype were responsible for MDC production in this Th2-oriented disorder. Thus, DC are the predominant source of MDC in vitro and in vivo under a variety of experimental and clinical conditions. Processing of MDC to MDC(3-69) and shorter forms which do not recognize CCR4 is likely to represent a feedback mechanism of negative regulation.

Cells, Cultured↗
PubMed2000

VEINCTR-N, an immunogenic epitope of Fas (CD95/Apo-I), and soluble Fas enhance T-cell apoptosis in vitro. II. Functional analysis and possible implications in HIV-1 disease.

BACKGROUND: Recent studies indicate that soluble Fas (sFas) may modulate T-cell apoptosis, since it inhibits Fas-ligand (Fas-L)-mediated cytotoxicity in vitro. Here, we explored whether the soluble receptor and its major immunogenic domain, namely VEINCTR-N, interfered with apoptosis of T cells from human immunodeficiency virus-type 1 (HIV-1)+ subjects showing serum elevations of both the soluble receptor and anti-Fas antibodies, and with that of several T-cell lines. MATERIALS AND METHODS: Both proliferation and apoptosis extent of T cells from 16 HIV-1+ patients showing serum anti-VEINCTR-N immunoglobulin G (IgG) and 15 controls were tested after incubation with sFas and three 8-mer peptides of its first consensus sequence that included VEINCTR-N. Several cell lines were also investigated by flow cytometry for their expression of Ki-67, the APO2.7-related mitochondrial protein, and the annexin-V. In addition, we evaluated the expression of Fas-L and caspases FLICE, CPP32 and ICE either by flow cytometry, immunoblotting, and/or reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Cell proliferation in cultures from both patients and controls was affected significantly by sFas and VEINCTR-N. However, a prevalent increase of the subdiploid DNA-containing cell population occurred within these cultures. Similarly, Jurkat, CEM cells, and a mouse WR19L transformant overexpressing native human Fas underwent prompt apoptosis, which was detected as enlargement of APO2.7-reactive and annexin-V-positive populations. By exploring the Fas pathway in Jurkat cells, we found that both apoptosis inducers acted through Fas, since Fas-L, as well as CPP32 and FLICE were activated. By contrast, ICE was up-regulated only in control cells treated with tumor necrosis factor alpha (TNFalpha). CONCLUSIONS: These data suggest that the soluble molecular forms of Fas prime cell death in Fas-positive cells. Therefore, the shedding of high amounts of sFas in HIV- 1 disease is possibly entrusted with amplification of the death execution program by cells functionally exhausted and committed to die. It is conceivable that the appearance of anti-Fas antibodies reflects an attempt by the immune system to neutralize these effective forms of the receptor and its structurally degraded domains, such as VEINCTR-N.

Amino Acid Sequence↗
PubMed2000

Whipple's disease. Description of a case and survey of the literature.

A case of Whipple's disease (WD) personally observed is described. A 28-year-old male was admitted to hospital for evaluation of weakness, intermittent fever and weight loss arisen since a month. On clinical investigation, he complained of vomit and diarrhea since three months. He had neither familial and personal past history of gastrointestinal diseases, nor any other important diseases. He denied use of drugs. Physical examination was negative. Laboratory findings showed anemia, low blood lymphocytes, low serum iron and total iron binding capacity, low total serum protein and low serum albumin and high level of ESR. Stool were negative for parasites and occult blood. Cultures of blood and urine were negative. Stool fat assay was > 7 g/24 h and D-xylose test showed a two-hour serum concentration < 25 mg/dl. Abdominal TC showed lumbo-aortic and mesenteric enlarged lymph nodes. An upper video endoscopy showed a duodenal lymphangectasia. Histological examination showed villar atrophy with massive infiltration of large PAS-positive diastase-resistant foamy cells. Ziehl-Nielsen staining was negative. WD was diagnosed and patient underwent therapy based on cotrimoxazole. This report emphasizes the difficulty to diagnose WD correctly, because of its rareness and clinical polymorphism. Recently, studies have identified a bacillus, Tropheryma whippelii, associated with WD, so that, in the next future, the diagnosis of WD will be faster and more accurate. Finally, it is important to administer antibiotics which can cross the blood brain barrier for at least one year, in order to prevent neurological relapse, often lethal.

Journal Article↗
PubMed1999

Nef protein induces differential effects in CD8+ cells from HIV-1-infected patients.

BACKGROUND: The Nef protein of HIV-1 is suspected to play a role in the depletion of uninfected CD4+ lymphocytes that leads to AIDS. By contrast its effect on CD8+ cells, whose functions are also deregulated during HIV-1 infection, is presently unclear. Here we describe a number of derangements induced in vitro by Nef in CD8+ cells from HIV-1-infected patients. DESIGN: Peripheral lymphocytes from 16 HIV-1+ subjects and 9 uninfected individuals were cultivated on a Nef-transfected mouse fibroblast layer exposing the carboxyl-terminal region of the viral protein on cell membrane. The cultures were then measured for both apoptosis and proliferation by subdiploid DNA content and Ki67 expression, respectively, whereas the molecular analysis of purified CD8+ cells investigated the Fas-L mRNA levels in Nef-treated CTLs. In addition, we evaluated the Nef-induced variation in the extent of CD8+/HLA-DR+ subset, which includes non cytotoxic cells secreting T-cell antiviral factor (CAF) and a soluble factor inhibiting the HIV-1 replication. RESULTS: The viral protein induced in peripheral blood lymphocytes (PBL) a moderate tendency to proliferate, as measured by the increment of Ki67 antigen, particularly on the CD8+ subset of HIV-1 infected individuals (P < 0.05). This profile was particularly evident in cultures from patients with severe CD4+ lymphopenia and paralleled an apparent expansion of the CD8+/CD57+ suppressor cell subset. Molecular analysis of purified CD8+ cells revealed a defective expression of Fas-L mRNA in Nef-cultured CTLs, whereas the viral protein exerted a down modulatory effect on the CD8+/HLA-DR+ subset (P < 0.05), thus suggesting a potential inhibition of CAF. CONCLUSIONS: These results support a potential role of Nef in the progression of HIV-1 infection as a number of cellular functions are affected in the CD8+ subset. In particular, the defective functions of CD8+ cells induced by the viral protein could contribute, at least partly, to the escape of HIV-1 from the immune control of these cells.

3T3 Cells↗
PubMed1998

Detectability of cochlear, acoustic nerve and brainstem potentials in a group of 'normal' preterm newborns recorded with insert earphone.

Thirty-four 'normal' preterm newborns were tested at 40 weeks postconceptional age. To separate electromagnetic artifacts from cochlear potentials and subsequent auditory brainstem responses, a test was given using an insert earphone at 90, 70, 50, 30 dB nHL. The detectability of receptor potentials, waves I, III, V, as a function of stimulus intensity is described: at 90 dB nHL exclusively, we could always identify these peaks because of the better morphological distinctiveness of each potential. When trying to evaluate the acoustic pathway in premature newborns, we suggest that brainstem response audiometry should be performed at 90 dB nHL with an insert earphone.

Acoustic Stimulation↗
PubMed1997

The corneal endothelium 12 months after photorefractive keratectomy in high myopia.

PURPOSE: To determine if photorefractive keratectomy with a 193 nm excimer laser could cause human corneal endothelial changes, mainly in high dioptric treatments. METHODS: 18 patients underwent a treatment ranging from 7 to 13 diopters at the corneal apex (mean 10.3 +/- 1.4 SD) with an estimated corneal thinning ranging from 62 to 116 microns (mean 90.7 +/- 12 SD). In these patients a comparison between the number and shape of the corneal endothelial cells has been performed before and 12 months after PRK. RESULTS: The mean cell density was 2818 +/- 337 mm2, before surgery, and 2894 +/- 301 mm2 after 12 months. The polymorphic index was 79.0 +/- 2.3, before surgery, and 81.0 +/- 5.0 after 12 months with no significant changes (p = 0.16 and P = 0.09, respectively). CONCLUSIONS: These results show that photorefractive keratectomy does not cause any significant observable damage to the central corneal endothelium up to 12 months after surgery, even in high myopic treatments.

Adult↗
PubMed1997

Endothelial cells evaluation two years after photorefractive keratectomy.

To evaluate long-term corneal endothelium damages after myopic photorefractive keratectomy (PRK) a morphometric analysis of corneal endothelial cells was performed in 41 patients before and at least 24 months after photorefractive keratectomy. These patients underwent a treatment ranging from -2.5 to -14 dpt with a mean of 8.9 +/- 2.8 dpt at the corneal apex, with an estimated corneal thinning ranging from 23 to 123 microns with a mean of 78 +/- 24.4 microns. Our results showed that the density of endothelial cells ranged from 2,334 to 3,554/mm2 with a mean of 2,819 +/- 351/mm2 before surgery, and from 2,051 to 3,461/mm2 with a mean of 2,774 +/- 330/mm2 after surgery without any significant changes (p = 0.16). The polymorphic index ranged from 58 to 84 with a mean of 77 +/- 5.7 before PRK and from 57 to 89 with mean of 77.7 +/- 7.2 after treatment without any significant changes (p = 0.61). In conclusion, we can state that there is no long-term corneal endothelial damage after PRK even in highly myopic eyes.

Adolescent↗
PubMed1996

The ability of bacteria to use Na-hyaluronate as a nutrient.

The objective of this study was to test bacteria ability to use Na-hyaluronate as a nutrient in vitro. Thirteen bacteria strains were tested in three different media: specific culture medium, agar-Healon medium and agar-Healon GV medium. The bacterial growth criteria were determined by counting the number of new colonies appearing at each observation time (0, 24, 48 and 72 h). The results were expressed as the percentage of growth in agar-Na-hyaluronate compared to each corresponding specific culture medium. After 24 h in the medium containing agar-Healon, S. aureus, S. epidermidis, S. pyogenes and S. viridans grew using hyaluronic acid as a nutrient. The percentage of growth of these species remained constant over the follow-up period. The other bacteria strains tested were unable to use Healon as a nutrient. After 24 h of incubation in the medium containing agar-Healon GV, S. aureus, S. epidermidis, S. pyogenes, and S. viridans exhibited about 20% growth. Subsequently, this percentage slowly increased to about 50%. The other bacteria stains tested were unable to employ Healon GV as a nutrient. With the exception of Staphylococci and Streptococci, the other species do not synthesize the necessary enzymes to break glucosidic bonds, therefore neither concentration of hyaluronic acid can be utilized as a source of carbohydrate for their survival in culture media.

Bacteria↗
PubMed1995

Effects on the corneal endothelium six months following photorefractive keratectomy.

Photorefractive keratectomy (PRK) with a 193-nm excimer laser has been shown not to destroy endothelial cells in vivo. However, this laser could damage endothelial cell metabolism, and result in damage over a longer term. In this paper, a comparison between the number and shape of corneal endothelial cells has been performed in 25 patients before and 6 months after PRK. These patients underwent treatment with myopic correction ranging from 2.5 to 17 dpt and with an estimated corneal thinning ranging from 25 to 170 microns. No significant changes in the number (p = 0.167) and shape (p = 0.075) of endothelial cells have been found. These results show that there are no long-term damages after PRK even in severely myopic eyes.

Adult↗
PubMed1994

Local specific immunotherapy in allergic conjunctivitis.

We evaluated the effect of local specific immunotherapy in 40 patients suffering from seasonal allergic conjunctivitis. Twenty patients received saline solution in both eyes; and 20 others received local specific immunotherapy in both eyes. Sodium cromoglycate drops were instilled in both eyes in all patients. Subjective and objective symptoms, and cytological findings had significantly improved after 1 year in the group treated with local specific immunotherapy plus sodium cromoglycate compared to the group treated with sodium cromoglycate and saline solution.

Adolescent↗
PubMed1994

Direct immunofluorescence and scraping conjunctival cytology in the study of 912 patients affected by microfollicular conjunctivitis.

912 patients affected by microfollicular conjunctivitis were submitted to a scraping conjunctival cytology before taking specimens for direct immunofluorescence. 264 patients proved to be positive to the direct immunofluorescence test for Chlamydia trachomatis (CT). In all cases the infection turned out to be bilateral with different degrees of positivity between one eye and the other. In 43 patients out of the 264 positive ones, the cytological examination showed the presence of eosinophils in both eyes. The presence of eosinophils poses the problem of a certain allergizing power of Chlamydia and of the possibility that the CT infection might easily develop in subjects with a preexistent allergic conjunctivitis.

Adolescent↗
PubMed1994

Fungal keratitis due to Scopulariopsis brevicaulis in an eye previously suffering from herpetic keratitis.

In the case reported, herpes virus I after having caused relapsing keratitis in an eye promoted the formation of a severe corneal ulcer caused by Scopulariopsis brevicaulis, a saprophytic mycete found in soil, which only once has been described as the cause of keratitis in man. Scopulariopsis was identified microscopically after culturing the conjunctival secretion on Sabouraud dextrose agar medium, while DNA probe tests confirmed the absence of herpes virus I. Topical and oral administration of miconazole and scraping of the corneal infiltrate dispersed the infection. Subsequently local steroids were given to reduce the neovascularization, and a therapeutic contact lens was applied because of intercurrent corneal thinning. Three months after beginning antifungal therapy, the visual acuity had increased from 1/120 to 1/10. The case described confirms that S. brevicaulis can cause opportunist infections in a cornea previously damaged by a different agent.

Conjunctiva↗
PubMed1990

Laboratory survey of Chlamydia trachomatis ocular infections.

The authors used immunofluorescence and immunoperoxidase tests to study a group of 101 patients with acute or chronic conjunctivitis, etiologically unrelated to conventional bacterial pathogens, and a control group of 30 healthy adults. Positive titers of IgG in serum and of IgA in lacrimal secretions against Chlamydia, detected by IPA, correlated with the identification of microorganisms by direct immunofluorescence. The use of both tests allows a precise evaluation of the stage of the infection and of its evolutive pattern.

Adult↗
PubMed1987

Cefamandole concentrations in the anterior chamber of the eye in rabbits and humans.

Cefamandole concentrations were determined in the aqueous humor of the anterior chamber of the eye in 10 rabbits and in 15 patients undergoing cataract extraction. The rabbits received 50 mg of cefamandole per kilogram of body weight in the ear vein and humans received 2 g of cefamandole by intravenous injection before operation. The levels recovered were several times higher than the minimum inhibitory concentrations (MICs) against the bacteria that are most often responsible for ocular infections.

Aged↗