PubMed Health⌕ Search

Biomedical subjects

A Scala

Publications and source records attributed to A Scala.

At least 55 records · Page 3Linked to original sources
PubMed2000

Glycoglycerolipid analogues active as anti-tumor-promoters: the influence of the anomeric configuration.

The in vitro anti-tumor promoting effect of monohexanoates of 2-O-alpha-D-gluco- and galactopyranosyl-sn-glycerol on the 12-O-tetradecanoylphorbol-13-acetate (TPA) induced Epstein-Barr virus early antigen (EBV-EA) activation was evaluated and compared to the potencies of the corresponding beta-anomers. The results show that the inversion of the anomeric configuration from beta to alpha does not seem to significantly influence the activity, which is present, as for the beta-anomers, even at 1x10 mol ratio without any cytotoxicity.

Anticarcinogenic Agents↗
PubMed2000

Functional expression of the gene cu, encoding the phytotoxic hydrophobin cerato-ulmin, enables Ophiostoma quercus, a nonpathogen on elm, to cause symptoms of Dutch elm disease.

We studied the involvement of the phytotoxic hydrophobin cerato-ulmin (CU) in pathogenesis and virulence of Dutch elm disease (DED) by expressing its encoding gene (cu) in Ophiostoma quercus, a nonpathogenic species on elm closely related to the DED pathogens O. ulmi and O. novo-ulmi. The production of the toxin was quantitatively determined in culture filtrates and in mycelial extracts of the transformants. Production of CU in vitro was associated with the ability to cause typical DED symptoms, consisting of foliar yellow and wilting and vascular tissue discoloration on a moderately resistant elm genotype. The presence of CU was monitored by enzyme-linked immunosorbent assay in symptomatic leaves of plants inoculated with O. quercus transformants expressing CU and found to be associated with wilt symptoms. In general, the virulence of the cu-expressing transformants, as measured in terms of vascular discoloration and percentage of defoliation, was lower than that of the mildly pathogenic isolate E2 of O. ulmi. However, one transformant (C39) displayed a virulence level intermediate between that of E2 and 182, a highly virulent isolate of O. novo-ulmi. Our results indicate that CU production influences virulence in nonaggressive strains of Ophiostoma fungi.

Ascomycota↗
PubMed2000

Free energy surface of supercooled water

We present a detailed analysis of the free energy surface of a well characterized rigid model for water in supercooled states. We propose a functional form for the liquid free energy, supported by recent theoretical predictions [Y. Rosenfeld and P. Tarazona, Mol. Phys. 95, 141 (1998)], and use it to locate the position of a liquid-liquid critical point at T(C')=130+/-5 K, P(C')=290+/-30 MPa, and rho(C')=1.10+/-0.03 g/cm(3). The observation of the critical point strengthens the possibility that the extended simple point charge model of water may undergo a liquid-liquid phase transition. Finally, we discuss the possibility that the approach to the liquid-liquid critical point could be pre-empted by the glass transition.

Journal Article↗
PubMed1999

Purification, characterization, and amino acid sequence of cerato-platanin, a new phytotoxic protein from Ceratocystis fimbriata f. sp. platani.

A new phytotoxic protein (cerato-platanin) of about 12.4 kDa has been identified in culture filtrates of the Ascomycete Ceratocystis fimbriata f. sp. platani, the causal agent of canker stain disease. The toxicity of the pure protein was bioassayed by detecting the inducing necrosis in tobacco leaves. The pure protein also elicited host synthesis of fluorescent substances in tobacco and plane (Platanus acerifolia) leaves. We purified the protein from culture medium to homogeneity. Its complete amino acid sequence was determined; this protein consists of 120 amino acid residues, contains 4 cysteines (S-S-bridged), and has a high percentage of hydrophobic residues. The molecular weight calculated from the amino acid sequence agrees with that determined by mass spectrometry, suggesting that no post-transnational modification occurs. Searches performed by the BLAST program in data banks (Swiss-Prot, EBI, and GenBank(TM)) revealed that this protein is highly homologous with two proteins produced by other Ascomycete fungi. One, produced during infection of wheat leaves, is codified by the snodprot1 gene of Phaeosphaeria nodorum (the causal agent of glume blotch of wheat), whereas the other is the rAsp f13 allergen from Aspergillus fumigatus. Furthermore, the N terminus of cerato-platanin is homologous with that of cerato-ulmin, a phytotoxic protein belonging to the hydrophobin family and produced by Ophiostoma (Ceratocystis) ulmi, a fungus responsible for Dutch elm disease.

Amino Acid Sequence↗
PubMed1999

Inhibitory effects of monoacylated 2-O-beta-galactosylglycerols on Epstein-Barr virus activation: the significant role of the hexanoyl chain.

Three series of monoacyl-2-O-beta-D-galactosylglycerols bearing an acyl chain of varying length, from C4 to C10, were studied due to their antitumor promoting effects on the activation of the Epstein-Barr virus early antigen (EBV-EA), such activation being induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). This study indicates that it is more the length of the acyl chain that is important for the activity, six carbon atoms resulting in maximum effect, rather than the position of the ester function and the nature of the sugar (galactose or glucose).

Antigens, Viral↗
PubMed1999

Chemoenzymatic synthesis and antitumor promoting activity of 6'- and 3-esters of 2-O-beta-D-glucosylglycerol.

Through a simple chemoenzymatic approach 6'- and 3-esters of 2-O-beta-D-glucosylglycerol 1, with short-medium length fatty acid acyl chains, were prepared. The study of their in vitro antitumor promoting effect on Epstein-Barr virus early antigen (EBV-EA) activation, in comparison with that of the 1-esters previously described, confirms the significant activity of such monoacylated glycoglycerolipid analogues and establishes for the glucose series that the 1-substitution and the hexanoyl chain are the proper structural features for the maximum activity.

Anticarcinogenic Agents↗
PubMed1999

Quasicrystals in a monodisperse system.

We investigate the formation of a two-dimensional quasicrystal in a monodisperse system, using molecular dynamics simulations of hard-sphere particles interacting via a two-dimensional square-well potential. We find that more than one stable crystalline phase can form for certain values of the square-well parameters. Quenching the liquid phase at a very low temperature, we obtain an amorphous phase. By heating this amorphous phase, we obtain a quasicrystalline structure with fivefold symmetry. From estimations of the Helmholtz potentials of the stable crystalline phases and of the quasicrystal, we conclude that the observed quasicrystal phase can be the stable phase in a specific range of temperatures.

Journal Article↗
PubMed1999

Waterlike anomalies for core-softened models of fluids: one dimension.

We use a one-dimensional (1D) core-softened potential to develop a physical picture for some of the anomalies present in liquid water. The core-softened potential mimics the effect of hydrogen bonding. The interest in the 1D system stems from the facts that closed-form results are possible and that the qualitative behavior in 1D is reproduced in the liquid phase for higher dimensions. We discuss the relation between the shape of the potential and the density anomaly, and we study the entropy anomaly resulting from the density anomaly. We find that certain forms of the two-step square-well potential lead to the existence at T=0 of a low-density phase favored at low pressures and of a high-density phase favored at high pressures, and to the appearance of a point C' at a positive pressure, which is the analog of the T=0 "critical point" in the 1D Ising model. The existence of point C' leads to anomalous behavior of the isothermal compressibility K(T) and the isobaric specific heat C(P).

Journal Article↗
PubMed1999

Non neoplastic tongue diseases. An epidemiological investigation and diagnostic criteria.

BACKGROUND: Few clinical-epidemiological data regarding tongue diseases were showed in recent literature. The aim of this study was to evaluate the prevalence of non neoplastic tongue pathologies, and to perform an epidemiological, clinical and etiopathogenetic comparable data system on Non-Neoplastic Glossitis (NNG). METHODS: A total of 215 subjects (90 males and 125 females, age range: 6-72 years) have been examined) at the Dental Clinic of the University of Brescia over a period of 2 years. From this group, patients with tongue non neoplastic lesions were selected. Each selected patient with NNG was examined, following the Diagnostic Protocol of the "Department of Oral Pathology and Medicine" of the Dental Clinic of Brescia University. RESULTS: 84 cases of NNG (39%) were observed from January 1997 to October 1998. CONCLUSIONS: The selected group of patients with NNG has been stratified following clinical and etiological criteria, and the results discussed, emphasizing the importance of careful and correct examination of the tongue, in order to bring to light morphological and pathological changes often neglected or misdiagnosed. One should never exclude, moreover the possibility of malignant evolution of some lingual lesions requiring a close follow-up.

Adolescent↗
PubMed1998

Inhibitory effects of fatty acid monoesters of 2-O-beta-D-glucosylglycerol on Epstein-Barr virus activation.

In a screening for cancer chemopreventing agents several glycosylglycerols were found to be active. In order to optimize the anti-tumor activity of this class of compounds, a series of 1-O-acyl-2-O-beta-D-glucopyranosyl-sn-glycerols differing in the acyl chain length, which varied from C4 to C18, were examined for their in vitro anti-tumor promoting effects on Epstein-Barr virus early antigen (EBV-BA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Among the compounds tested, the monohexanoyl derivative was the most active and, noteworthy, the most potent compound of the glycosylglycerol series hitherto known.

Antigens, Viral↗
PubMed1995

Different patterns of meniscal tears in acute anterior cruciate ligament (ACL) ruptures and in chronic ACL-deficient knees. Classification, staging and timing of treatment.

Through the retrospective study of 1103 reconstructions of the anterior cruciate ligament (ACL) performed between 1984 and 1993, we try to outline the natural history of meniscal tears in acute lesions and in chronic insufficiency of the ACL. According to a more accurate evaluation of the clinical evolution, ACL-deficient knees can be classified into four different stages: acute, subacute, subchronic and properly chronic laxities. While acute injuries show a higher rate of lateral meniscus tears, chronic laxities are very frequently associated with severe medial meniscus lesions. Subacute and subchronic stages seem therefore to be the most favourable phases for ACL reconstruction, because of the lower percentage of severe associated meniscus tears and the minor risk of arthrofibrosis.

Acute Disease↗
PubMed1994

Arthroscopic treatment of the flexed arthritic knee in active middle-aged patients.

Twenty patients (22 knees) treated by arthroscopic removal of the anterior tibial osteophyte were selected for review from more than 150 arthroscopic debridements of the knee over a 5-year period (1986-1991). All the patients were middle-aged active individuals with competitive sports activity in their past. Their main complaint was flexion deformity of the knee (5 degrees-20 degrees) associated with pain and discomfort in recreational sporting activities and/or in activities of daily living. Roentgenographic examination in all cases showed an anterior tibial osteophyte located just anterior and medial to the anteromedial tibial spine of the intercondylar eminence. No varus or valgus malalignment or subchondral necrosis was detected. Arthroscopic treatment consisting of removal of the anterior tibial osteophyte by shaving and extraction of the bone, followed by a moderate notchplasty, was sufficient to improve the active extension of the knee and to decrease the pain and stiffness of the joint.

Adult↗
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↗