Giorgio Lampis

Pyrrolnitrin and related pyrroles endowed with antibacterial activities against Mycobacterium tuberculosis

During development of nitroheterocycles with potential antimycobacterial activities we have tested against Mycobacterium tuberculosis a number of pyrroles strictly related to pyrrolnitrin, an antifungal antibiotic isolated from Streptomyces pyrrocinia. Some of the tested arylpyrrole derivatives and pyrrolnitrin have shown appreciable inhibiting activity against M. tuberculosis and M. avium. SAR studies well correlate antimycobacterial potency with the presence of halogens in the phenyl ring and a nitro group at position 3 of pyrrole.

Antiviral activity of new triterpenic derivatives

Twenty-seven triterpenic derivatives of glycyrrhetinic, oleanolic, ursolic and maslinic acid were tested for antiviral and cytotoxic properties. Twelve of them showed apparent antiviral activity against at least one of the tested viruses. The most active compounds were PAS-T45 and 48 which exerted a protection index of 4 on vaccinia virus.

Production of lysozyme‐enriched biomass from cheese industry by‐products

Cheese whey and cottage cheese whey are by‐products of the milk and cheese industry, resulting from the production of cheese and cottage cheese (ricotta) from milk. They are still rich in organic substances and cannot be discarded into the environment without proper treatment. Whey and cottage cheese whey were used as culture media for some strains of the yeast Kluyveromyces lactis, transformed with the human lysozyme gene. It was found that the yeast strains grew well in both media and produced a considerable amount of recombinant protein. Production kinetics showed that the human lysozyme was produced in a greater amount within 36 h of fermentation (125 μg ml−1vs 25 μg ml−1 in the control) than in the synthetic commercial media used for strain preparation and characterization. The recombinant protein produced was actually shown to be the human lysozyme, using renaturing SDS‐PAGE and Western blot techniques. While producing recombinant protein, the Kluyveromyces strain cleared the cottage cheese whey of most organic substances and produced a considerable amount (almost 3%) of lysozyme‐enriched useful biomass.

Presence of pituitary adenylate cyclase-activating polypeptide receptors in Y-79 human retinoblastoma cells.

Abstract: Cytochemical analysis demonstrated that a high percentage of human Y‐79 retinoblastoma cells displayed a specific labeling by the biotinyl derivative of pituitary adenylate cyclase‐activating polypeptide (PACAP), a novel neuropeptide of the secretin‐vasoactive intestinal peptide (VIP) family of peptides. In cell membranes, the two molecular forms of PACAP, the one with 38 (PACAP 38) and the other with 27 (PACAP 27) amino acids, displaced the binding of 125I‐PACAP 27 with IC50 values in the picomolar range and increased adenylyl cyclase activity by 100‐fold with EC50 values of 27 and 180 pM, respectively. VIP, human peptide histidine‐isoleucine, glucagon, and secretin were much less effective and potent in both receptor assays. The PACAP receptor antagonists PACAP 6–27 and PACAP 6–38 and an antiserum directed against the stimulatory G protein Gs inhibited the PACAP stimulation of adenylyl cyclase. In intact cells, both PACAPs and VIP failed to stimulate the phosphoinositide hydrolysis, whereas in cell membranes PACAP 38, but not the other peptides, produced a modest increase (40%) of inositol phosphate formation with an EC50 value of 22 nM. However, this effect was not antagonized by either PACAP 6–38 or PACAP 6–27. These data demonstrate the presence in human Y‐79 retinoblastoma cells of specific PACAP receptors and provide further evidence that PACAP may act as a neurotransmitter/neuromodulator in mammalian retina.

Enhancement of anti-herpetic activity of glycyrrhizic acid by physiological proteins

Some enzymes present in biological fluids, such as lysozyme (LYS) and lactoferrin (LAC), are known to possess antibacterial and antiviral activity, against herpesviruses in particular. It will be shown in this paper that their combination with a natural triterpene, namely glycyrrhizic acid (GLA), gives significant results in enhancing the antagonistic activity on HSV1 in in vitro assays. Data elaboration was carried out by calculation of the FIC index (fractional inhibitory concentration) for each combination of the three compounds and by a three-dimensional evaluation of the inhibiting combinatory effects, which indicated the percentage of the synergistic action. A FIC index equal to or below 0.5 demonstrated a significant synergistic effect between two substances. Considering each single compound, the 50% inhibiting doses on viral replication (ID50) were 252±53 μg/ml for LAC, 497±165 μg/ml for LYS and 740±125 μg/ml for GLA. The combination of LAC and GLA showed a clear synergistic effect, with a FIC index of 0.08 and a potentiating activity which, for some doses, was up to 1.5 log10 of difference (from about 5.5×106 to 105 pfu/ml). The combinations of GLA and LYS, and LYS and LAC showed a less significant synergistic activity. These findings led to the conclusion that some physiological proteins, even at concentrations usually present in some body fluids, may enhance the anti-herpetic activity of a natural compound such as GLA.

N-[4-(1,1′-biphenyl)methyl]-4-(4-thiomorpholinylmethyl) benzenamines as non-oxazolidinone analogues of antimycobacterial U-100480

Thiomorpholine analogues of U-100480 with the biphenylmethyl group replacing the acetamidomethyloxazolidinone moiety have been synthesized and tested as antimycobacterial agents together with various related derivatives. Some biphenyl derivatives were endowed with high activity against Mycobacterium tuberculosis and other non-tuberculous mycobacteria.

Antimycobacterial activity of new ortho-, meta- and para-toluidine derivatives

Novel toluidine derivatives are described. Some of them showed an interesting in vitro activity against Mycobacterium tuberculosis, M. smegmatis, M. marinum, M. gordonae, and M. avium. Some of them were more active than Streptomycin and Isoniazid, which were used as controls, against M. avium and M. gordonae. In particular, we confirm the good activity of biphenyl derivatives.

Allergy and Tumour Outcome after Primary Cancer Therapy

Background: Over the last decade several papers have dealt with the possible interference of allergies in both the infectious disease incidence and tumour development. In the light of all these observations we analysed several tumour patients for a possible interaction between a state of allergy and tumour development and progression after primary cancer therapy. Methods: This study included 1,055 patients with different types of solid tumours admitted consecutively between 1994 and 2002 to the Cagliari University Polyclinic. After primary surgery or medical therapy (or both), 92 allergic subjects and 182 non-allergic patients were studied over a follow-up period of 6–96 months (median 23). Results: Among 1,055 tumour-bearing patients, the prevalence of allergy was found to be about 8% versus 16–37% in a population of non-tumour-bearing subjects. After primary cancer therapy, allergic patients turned out to have a 20% higher probability of being cured and about a 50% lower risk of tumour progression as compared to non-allergic ones. The observed differences were statistically significant (p = 0.013). Conclusions: On the basis of our findings, we suggest that allergic subjects seem to have a better prognosis than non-allergic ones for disease outcome after cancer therapy.

Human Y-79 retinoblastoma cells exhibit specific corticotropin-releasing hormone binding sites

Abstract: In this study we have identified specific binding sites for corticotropin‐releasing hormone (CRH) in human Y‐79 retinoblastoma cell membranes by using 125I‐Tyrovine CRH (125I‐oCRH) as radioligand. Binding at 19°C was rapid with steady state being reached within 20 min, reversible and linear with membrane protein concentration. The 125I‐oCRH binding was enhanced by Mg2+ and inhibited by the GTP analogue guanosine 5′‐O‐(3′‐thiotriphosphate). Y‐79 cell membranes exhibited two populations of binding sites, a high‐affinity site with an apparent dissociation constant (KD) of 1 nM and a low‐affinity site with an apparent KD of 500 nM. 125I‐oCRH binding was completely antagonized by human/rat CRH, [Met(O)21]oCRH, α‐helical CRH9–41, urotensin I, and sauvagine with a rank order of potency similar to that displayed by CRH receptors of other tissues. These data describe for the first time the presence of specific CRH‐binding sites in retinal cells. The Y‐79 cell line may therefore constitute a valuable model in which to study CRH action on retinal cells.

Human Y-79 retinoblastoma cells express functional corticotropin-releasing hormone receptors.

In human Y-79 retinoblastoma cells corticotropin-releasing hormone (CRH) produces a marked and rapid increase of adenylate cyclase activity. The concentration of the peptide producing half-maximal stimulation is 60 nM. The effect of CRH is significantly antagonized by the specific CRH receptor antagonist alpha-helical CHR 9-41 and is mimicked by sauvagine and urotensin I, two peptides displaying sequence homology with CRH. These results demonstrate the presence of functional CRH receptors in human Y-79 retinoblastoma cells and suggest that this cell line may be a suitable model in which to study the action of CRH on human retinal cell function.