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1.
Hand Ther ; 26(3): 91-101, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37904881

RESUMO

Introduction: Several general hand functional assessment tools for Dupuytren's disease have been reported, but none of the patient-reported-outcome measures specific to Dupuytren's disease-associated disabilities are available in the Italian language. The purpose of this study was to culturally adapt the Unité Rhumatologique des Affections de la Main (URAM) into Italian (URAM-I) and determine its measurement properties. Methods: Cross-cultural adaptation was performed according to the current guidelines. Construct validity (convergent and divergent validity) was measured by comparing the URAM-I with the Pain-Rated Wrist/Hand Evaluation (PRWHE-I), Short-Form 36 (SF-36-I) scale and finger range of motion, respectively. Factor analysis was used to investigate the URAM-I's internal structure. Reliability was assessed by internal consistency (Cronbach's alpha) and test-retest reliability by Intra-Class Correlation Coefficient (ICC). Results: This study included 96 patients (males = 85%, age = 66.8 ± 9.3). Due to the cultural adaptation, we divided the original item #1 into two separate items, thus generating the URAM-I(10). Convergent validity analysis showed a strong positive (r = 0.67), significant (p < 0.01) Pearson's correlation with the PRWHE-I. Divergent validity analysis showed a weak, negative (r < 0.3) and not significant correlation with the SF-36-I subscales, except for the physical pain subscale (r = -0.21, p < 0.05). Factor analysis revealed a 2-factor, 4-item solution that explained 76% of the total variance. The URAM-I(10) demonstrated high internal consistency (α = 0.94) and high test-retest reliability (ICC = 0.97). Conclusion: The URAM-I(10) demonstrates moderate construct validity, high internal consistency and test-retest reliability, and showed a 2-factor internal structure. Its evaluative use can be suggested for the Italian Dupuytren's population.

2.
Chem Commun (Camb) ; 52(7): 1458-61, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26650111

RESUMO

Unprecedented domino oxidative cyclization reactions of unprotected 2-alkynylanilines to give functionalized 4H-benzo[d][1,3]oxazin-4-one or benzisoxazole derivatives in moderate to good yields are achieved by silver vs. gold selective catalysis. The search for the optimal reaction conditions revealed the divergent catalytic activity of NaAuCl4·H2O and AgNO3.


Assuntos
Compostos de Anilina/química , Ouro/química , Prata/química , Ácidos Sulfúricos/química , Catálise , Ciclização , Oxirredução
3.
Mediators Inflamm ; 2015: 732539, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26236110

RESUMO

BACKGROUND: The role of prolactin (PRL) on tissue injury and repair mechanisms in multiple sclerosis (MS) remains unclear. The aim of this work was to investigate the relationship between PRL plasma levels and brain damage as measured by magnetic resonance imaging (MRI). METHODS: We employed a chemiluminescence immunoassay for measuring plasma levels of PRL. We used a 1.5 T scanner to acquire images and Jim 4.0 and SIENAX software to analyse them. RESULTS: We included 106 women with relapsing remitting (RR) MS and stable disease in the last two months. There was no difference in PRL plasma levels between patients with and without gadolinium enhancement on MRI. PRL plasma levels correlated with white matter volume (WMV) (rho = 0.284, p = 0.014) but not with grey matter volume (GMV). Moreover, PRL levels predicted changes in WMV (Beta: 984, p = 0.034). CONCLUSIONS: Our data of a positive association between PRL serum levels and WMV support the role of PRL in promoting myelin repair as documented in animal models of demyelination. The lack of an increase of PRL in the presence of gadolinium enhancement, contrasts with the view considering this hormone as an immune-stimulating and detrimental factor in the inflammatory process associated with MS.


Assuntos
Esclerose Múltipla/sangue , Prolactina/sangue , Substância Branca/patologia , Adolescente , Adulto , Feminino , Gadolínio , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Esclerose Múltipla/metabolismo , Esclerose Múltipla/patologia , Adulto Jovem
4.
Neurol Sci ; 31 Suppl 3: 303-7, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20535513

RESUMO

We reported a post-marketing experience of 190 patients affected by relapsing multiple sclerosis on treatment with natalizumab. Clinical findings during pre-treatment period and throughout the study were documented. Magnetic resonance imaging (MRI) scans were performed at baseline and at 6, 12, and 24 months of therapy. Cumulative proportions of patients disease activity free (i.e. absence of relapses, disability progression, MRI activity) were measured as efficacy endpoints. Despite that the baseline characteristics suggested a more severe course of disease in our sample than that of the AFFIRM trial, data on effectiveness of natalizumab were comparable. At 1 year of treatment we found 80 and 70% patients free from relapses and MRI activity, respectively, that is similar to 75 and 62% detected in the AFFIRM trial. Moreover, only 5% of our patients showed a progression of disability after a mean follow-up time of 15 months. Finally, the presence of antibodies anti-Natalizumab was strongly related to the occurrence of relapses (p = 0.002) and MRI activity (p < 0.001) even in the post-marketing experience.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Esclerose Múltipla/terapia , Vigilância de Produtos Comercializados/tendências , Adulto , Anticorpos Monoclonais Humanizados/efeitos adversos , Hipersensibilidade a Drogas/epidemiologia , Hipersensibilidade a Drogas/imunologia , Hipersensibilidade a Drogas/terapia , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética/tendências , Masculino , Esclerose Múltipla/epidemiologia , Esclerose Múltipla/imunologia , Esclerose Múltipla/fisiopatologia , Natalizumab , Estudos Prospectivos , Cidade de Roma/epidemiologia , Resultado do Tratamento
5.
Phys Chem Chem Phys ; 12(29): 8300-10, 2010 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-20582364

RESUMO

UV and IR photoreactivities of acetylacetone isolated at 4.3 K in four matrixes (N(2), Ne, Ar, Xe), pure and doped with O(2) are investigated, using either tunable UV and IR optical parametric oscillators, or a broad band mercury lamp. Samples are probed by UV and FTIR spectroscopies: electronic and vibrational transitions are assigned and irradiation kinetics are analyzed. Contrary to what is observed in the gas phase, stereoisomerization is the main reaction observed: UV irradiation breaks the strong H-bond of the stable enolic form of acetylacetone, leading to the observation of non-chelated forms. Isomerization among the different non-chelated forms as well as back-isomerization to the chelated form are also observed under UV irradiation. Similar reactions and reaction rates are observed for the four matrixes, indicating that the inter-system crossing to the T(1) state involved in the isomerization process is very fast, probably due to efficient coupling with phonons, in contrast with gas phase where inter-system crossing is rate-limiting. When matrixes are doped with O(2), dissociation of the non-chelated forms under UV irradiation is observed and fragments, in particular CO, are formed in large amounts. Dissociation through a Norrish type-I reaction is probably one of the reaction channels occurring during electronic relaxation: dissociation is hindered by the surrounding cage in the case of pure matrixes while fragments immediately react with O(2) in the case of doped matrixes. The differences between gas phase and cold solid medium photodynamics of acetylacetone are discussed.

6.
J Appl Microbiol ; 105(1): 105-15, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18217933

RESUMO

AIMS: To exploit the cyanobacterial diversity of microbial mats growing in the benthic environment of Antarctic lakes for the discovery of novel antibiotic and antitumour activities. METHODS AND RESULTS: In all, 51 Antarctic cyanobacteria isolated from benthic mats were cultivated in the laboratory by optimizing temperature, irradiance and mixing. Productivity was generally very low (

Assuntos
Antibacterianos/isolamento & purificação , Antifúngicos/isolamento & purificação , Cianobactérias/metabolismo , Microbiologia da Água , Regiões Antárticas , Aspergillus fumigatus/efeitos dos fármacos , Técnicas Bacteriológicas , Cryptococcus neoformans/efeitos dos fármacos , Cianobactérias/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Fotossíntese , Plâncton , Staphylococcus aureus/efeitos dos fármacos , Testes de Toxicidade
7.
J Appl Microbiol ; 99(4): 960-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16162249

RESUMO

AIMS: To identify microbial strains with esterase activity able to enantioselectively hydrolyse esters of (R,S)-1,2-O-isopropylidene glycerol. METHODS AND RESULTS: The microbial hydrolysis of various racemic esters of 1,2-O-isopropylidene glycerol (IPG) was attempted by screening among Streptomyces spp. previously selected on the basis of their carboxylesterase activity. The best results were observed in the hydrolysis of butyrate ester and two strains appeared promising as they showed opposite enantioselectivity: Streptomyces sp. 90852 gave predominantly (S)-IPG, while strain 90930 mostly gave the R-alcohol. Streptomyces sp. 90930 was identified as Streptomyces violaceusniger, whereas Streptomyces sp. 90852 is a new species belonging to the Streptomyces violaceus taxon. The carboxylesterase belonging to strain 90852 gave a maximum value of enantiomeric ratio (E) of 14-16. This strain was lyophilized and used as dry mycelium for catalysing the synthesis of isopropylidene glycerol butyrate in heptane showing reaction rate and enantioselectivity (E = 6.6) lower than what observed for the hydrolysis. CONCLUSIONS: A new esterase with enantioselective activity towards (R,S)-IPG butyrate has been selected. The best enantioselectivity is similar or even better than the highest reported value in the literature with commercial enzymes. The enzyme is produced by a new species belonging to the S. violaceus taxon. SIGNIFICANCE AND IMPACT OF THE STUDY: New esterases from streptomycetes can be employed for the enantioselective hydrolysis of chiral esters derived from primary alcohols, not efficiently resolved with commercial enzymes.


Assuntos
Glicerol/análogos & derivados , Streptomyces/enzimologia , Alcenos/metabolismo , Butiratos/metabolismo , Carboxilesterase/metabolismo , Catálise , Meios de Cultura , DNA Fúngico/genética , DNA Ribossômico/genética , Esterases/metabolismo , Ésteres/metabolismo , Liofilização , Glicerol/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Micélio/metabolismo , Filogenia , Análise de Sequência de DNA/métodos , Solventes , Streptomyces/genética , Streptomyces/isolamento & purificação , Temperatura
8.
J Appl Microbiol ; 98(2): 429-39, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15659197

RESUMO

AIMS: To evaluate the patterns of the production of antimicrobial compounds by Israeli myxobacteria newly isolated from soil samples and barks by a battery of isolation and purification methods. METHODS AND RESULTS: A total of 100 myxobacteria belonging to five of the 12 described genera, were isolated from 48 soil and 45 tree bark samples collected in different areas inside the State of Israel. Four isolation methods based on the peculiar metabolic and cell cycle aspects of myxobacteria, were combined with purification procedures and optimization of cultivation conditions. Ninety-seven strains were fermented and screened for antimicrobial activities. Production of antimicrobial activities was detected in 62 isolates. More than 50% of the collection (54 strains) was able to inhibit Escherichia coli growth. CONCLUSIONS: The results of this study support the idea that myxobacterial strains can be isolated from particular habitats and then cultivated and screened for their capacity to produce secondary metabolites endowed with antibacterial and antifungal activities. Myxovirescin, a typical poliketide myxobacterial antibiotic, has been identified in one Israeli isolate. Althiomycin, a thiazolyl peptide, which inhibits prokaryotic protein synthesis, usually produced by actinomycetes, was detected in three strains selected in this study. SIGNIFICANCE AND IMPACT OF THE STUDY: The results confirm that myxobacteria are prolific producers of a variety of bioactive secondary metabolites including antibacterial and antifungal compounds, being their high frequency of anti-Gram-negative activities particularly appealing for the current anti-infective research. So far their screening has often been hampered because their isolation is time-consuming and are quite difficult to handle and cultivate. In this paper we demonstrate that a proper combination of isolation, purification and cultivation methods allow their pharmaceutical exploitation.


Assuntos
Antibacterianos/biossíntese , Myxococcales/isolamento & purificação , Microbiologia do Solo , Técnicas Bacteriológicas , Reatores Biológicos , Israel , Myxococcales/classificação , Myxococcales/metabolismo , Casca de Planta
9.
J Chem Phys ; 121(24): 12548-58, 2004 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-15606276

RESUMO

The mechanism of hydrogen absorption between two coronene molecules has been studied by first principle calculations. Examination of different sites for H(2) molecule confirmed the classical picture of physisorption. We have also considered molecular hydrogen adsorption in a charged carbon structure achieved by doping with lithium at a density corresponding to the intercalate compound LiC(6). We have performed different types of calculations [Hartree-Fock and density functional theory (DFT)] for various atomic basis sets using CRYSTAL98, GAUSSIAN98, and DMOL3 codes. B3LYP-DFT (B3LYP-three-parameter functional of Backe, Lee, Yang and Parr) energy minimization calculations unravel that there is a stable adsorption site for molecular hydrogen in Li-doped sp(2) carbon structure. These calculations also give an insight into the atomic configurations of interlayer species (H(2) and Li) as the interlayer spacing increases. It can be shown that large changes occur in the positions and electronic properties of interlayer species. Hydrogen molecule does not show any tendency for dissociation and adopts a position in the interlayer void that is deeply related to that of lithium ions. We have evidenced a rather large charge transfer from lithium and capping hydrogen species on neighboring slab carbon atoms that induce the stabilization of molecular hydrogen. We have also found that rotating one carbon layer with respect to the other one (at constant interlayer distance) does not change the adsorption energy to a large extent. The best adsorption site is about five times deeper than the physisorption site found in the undoped case and occurs at an interlayer separation of 5.5+/-0.5 A. The corresponding atomic configuration consists in a hydrogen molecule standing (nearly) perpendicular to the plane surface surrounded by the three lithium ions in a configuration close to that of the LiC(6) intercalation compound.

10.
Mult Scler ; 10(4): 442-6, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15327043

RESUMO

Caregivers of persons with multiple sclerosis (MS) exhibit less satisfaction with quality of life with respect to the general population. To assess the relationship between depression in caregivers and health status profiles of MS patients, we examined data from 133 patients and their respective caregivers, as a part of a prospective randomized trial aimed to investigate the effectiveness of home-based care. Patients were evaluated at baseline and one year later with measures of physical and psychological impairment and health status (SF-36 Health Survey). Caregivers' psychological morbidity was assessed by the Profile of Mood State (POMS) at the same time points. An improvement of patients' health status as measured in four out of eight SF-36 dimensions was observed over the study period, while psychological morbidity of their caregivers did not change significantly. Depression in caregivers was related to physical, emotional and health status of the patients at baseline and/or at 12-month follow-up. Changes in the degree of depression of caregivers were also associated with changes in disability and health status of the patients. This study confirms and extends in a home-care setting previous findings on relationships between patients' status and depression in caregivers. It suggests that the caregiver is an appropriate and independent target for more focused therapeutic strategies.


Assuntos
Cuidadores/psicologia , Depressão , Nível de Saúde , Serviços de Assistência Domiciliar , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/terapia , Adulto , Afeto , Idoso , Depressão/psicologia , Pessoas com Deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/psicologia , Equipe de Assistência ao Paciente
11.
J Chem Phys ; 120(24): 11882-8, 2004 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-15268222

RESUMO

Boron inserted as impurity by substitution of carbon atoms in graphite is known to modify the reactivity of the surface in interaction with hydrogen. Boron induces a better H retention capability in graphite while it makes easier the recombination into molecular hydrogen under heating in thermal-desorption experimental conditions. It has already been calculated that boron modifies the electronic structure of the surface, which results in an increase of the adsorption energy for H. This result seems in good agreement with the better retention for H in doped graphite, but contradictory with the easier recombination observed. The aim of this work is to dismiss this contradiction by elucidating the modifications induced by boron in the recombination mechanism. We studied the diffusion of H on pure and boron-doped graphite in the density functional theory framework. We determined a diffusionlike mechanism leading to molecular hydrogen formation. Finally, we have shown the fundamental modifications induced by boron on the [0001] graphite surface reactivity. From these calculations it stands out that recombination is the result of desorption on pure graphite and diffusion on B-doped surfaces, while the activation energy for the rate limiting step is half reduced by boron. The results are compared to experimental observations. The connection between the cluster and periodic quantum modes for graphite is also discussed.

12.
J Neurochem ; 88(5): 1179-85, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15009673

RESUMO

An overactivation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)/kainate receptors has been implicated in the pathophysiology of oligodendrocyte damage in demyelinating disorders of the CNS. We decided to examine the effect of testosterone on excitotoxic death of oligodendrocytes because a gender difference exists in the incidence and disease course of multiple sclerosis. Short-term pure cultures of oligodendrocytes (4 days in vitro) were exposed to a brief pulse with kainate or AMPA + cyclothiazide for the induction of excitotoxicity. Exposure to testosterone enantate was slightly toxic per se and amplified both AMPA and kainate toxicity. Testosterone treatment induced all gene targets of p53, and amplified the induction of these genes induced by kainate. The effect of testosterone was mediated by the activation of androgen receptors and was resistant to the aromatase inhibitors, dl-aminoglutethimide and 4-hydroxyandrost-4-ene-3,17-dione. Testosterone treatment also potentiated the stimulation of 45Ca2+ influx induced by AMPA + cyclothiazide or kainate without changing the expression of the glutamate receptor (GluR) 1, -2/3, and -4 subunits of AMPA receptors or the GluR6/7 subunits of kainate receptors. We conclude that testosterone amplifies excitotoxic damage of oligodendrocytes acting at an early step of the death cascade triggered by AMPA/kainate receptors.


Assuntos
Neurotoxinas/toxicidade , Oligodendroglia/efeitos dos fármacos , Testosterona/farmacologia , Animais , Benzotiadiazinas/toxicidade , Cálcio/metabolismo , Cálcio/farmacocinética , Células Cultivadas , Sinergismo Farmacológico , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Expressão Gênica/efeitos dos fármacos , Ácido Caínico/toxicidade , L-Lactato Desidrogenase/metabolismo , Oligodendroglia/citologia , Oligodendroglia/metabolismo , Quinoxalinas/farmacologia , Ratos , Receptores de AMPA/antagonistas & inibidores , Receptores de AMPA/metabolismo , Receptores Androgênicos/efeitos dos fármacos , Receptores Androgênicos/metabolismo , Receptores de Ácido Caínico/antagonistas & inibidores , Receptores de Ácido Caínico/metabolismo , Fatores de Tempo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/toxicidade
13.
J Cell Physiol ; 198(2): 324-32, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-14603534

RESUMO

It has been recently established that low-frequency electromagnetic field (EMFs) exposure induces biological changes and could be associated with increased incidence of cancer, while the issue remains unresolved as to whether high-frequency EMFs can have hazardous effect on health. Epidemiological studies on association between childhood cancers, particularly leukemia and brain cancer, and exposure to low- and high-frequency EMF suggested an etiological role of EMFs in inducing adverse health effects. To investigate whether exposure to high-frequency EMFs could affect in vitro cell survival, we cultured acute T-lymphoblastoid leukemia cells (CCRF-CEM) in the presence of unmodulated 900 MHz EMF, generated by a transverse electromagnetic (TEM) cell, at various exposure times. We evaluated the effects of high-frequency EMF on cell growth rate and apoptosis induction, by cell viability (MTT) test, FACS analysis and DNA ladder, and we investigated pro-apoptotic and pro-survival signaling pathways possibly involved as a function of exposure time by Western blot analysis. At short exposure times (2-12 h), unmodulated 900 MHz EMF induced DNA breaks and early activation of both p53-dependent and -independent apoptotic pathways while longer continuous exposure (24-48 h) determined silencing of pro-apoptotic signals and activation of genes involved in both intracellular (Bcl-2) and extracellular (Ras and Akt1) pro-survival signaling. Overall our results indicate that exposure to 900 MHz continuous wave, after inducing an early self-defense response triggered by DNA damage, could confer to the survivor CCRF-CEM cells a further advantage to survive and proliferate.


Assuntos
Apoptose/efeitos da radiação , Campos Eletromagnéticos/efeitos adversos , Expressão Gênica/efeitos da radiação , Leucócitos/efeitos da radiação , Western Blotting , Ciclo Celular/genética , Ciclo Celular/efeitos da radiação , Divisão Celular/efeitos da radiação , Humanos , Fatores de Tempo , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/efeitos da radiação
14.
Appl Microbiol Biotechnol ; 61(5-6): 512-6, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12764566

RESUMO

Antibiotic production in many streptomycetes is influenced by extracellular gamma-butyrolactone signalling molecules. In this study, the gene scbA, which had been shown previously to be involved in the synthesis of the gamma-butyrolactone SCB1 in Streptomyces coelicolor A3(2), was deleted from the chromosome of Streptomyces lividans 66. Deletion of scbA eliminated the production of the antibiotic stimulatory activity previously associated with SCB1 in S. coelicolor. When the S. lividans scbA mutant was transformed with a multi-copy plasmid carrying the gene encoding the pathway-specific activator for either actinorhodin or undecylprodigiosin biosynthesis, production of the corresponding antibiotic was elevated significantly compared to the corresponding scbA(+) strain carrying the same plasmid. Consequently, deletion of scbA may be useful in combination with other strategies to construct host strains capable of improved bioactive metabolite production.


Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/genética , Proteínas de Ligação a DNA/genética , Genes Bacterianos , Streptomyces/genética , Streptomyces/metabolismo , 4-Butirolactona/biossíntese , Antraquinonas/metabolismo , Reatores Biológicos , Fermentação , Deleção de Genes , Plasmídeos/genética , Prodigiosina/análogos & derivados , Prodigiosina/biossíntese
15.
Eur J Neurol ; 10(1): 95-7, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12535003

RESUMO

The authors evaluated the gender difference in the magnetic resonance imaging characteristics of the lesions occurring in the brain of 413 multiple sclerosis (MS) patients. Men had fewer contrast-enhancing lesions (P = 0.01), but a higher proportion of lesions evolving into 'black holes' (P = 0.001), when compared with women. Thus, our data indicate that men with MS are prone to develop less inflammatory, but more destructive lesions than women. This study results provides support for a modulation of the MS pathological changes by gender.


Assuntos
Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/patologia , Caracteres Sexuais , Adulto , Distribuição de Qui-Quadrado , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas
16.
J Am Chem Soc ; 123(43): 10668-75, 2001 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-11673998

RESUMO

The structure and energy properties of the 1:1 complexes formed between cyanoacetylene and H2O (D2O) are investigated using FT-IR matrix isolation spectroscopy and ab initio calculations at the MP2/ 6-31G(d,p) level. Cyanoacetylene adsorption and desorption on amorphous ice film are monitored by FT-IR using the temperature-programmed desorption method. In an argon matrix, two types of 1:1 complexes are observed. The first one corresponds to the NH structure, which involves a hydrogen bond with the terminal nitrogen of cyanoacetylene. The second corresponds to the HO form, which involves a hydrogen bond from the cyanoacetylene to the oxygen of water. This last complex is the more stable (DeltaE = -8.1 kJ/mol.). As obtained in argon matrixes, two kinds of adsorption site are observed between HC3N and ice. The first one, stable between 25 and 45 K is characterized by a nu(OH) shift similar to the one observed in matrix for the NH complex. The second, stable at higher temperatures (between 45 and 110 K), corresponds to an interaction with the dangling oxygen site of ice and is similar to the HO complex observed in matrix. From theoretical calculations (DFT method combined with a plane wave basis set and ultrasoft pseudopotentials), it is shown that, for this adsorption site, the HC3N moiety is flattened on the ice surface and stabilized by a long-distance interaction ( approximately 3 A) between one dangling OH and the pi system of the C triple bond C triple bond. The HC3N desorption occurs between 110 and 140 K, and the associated desorption energy is 39 kJ/mol. This value is in good agreement with the first principle calculation based on density functional theory and ultrasoft pseudopotentials (34 kJ/mol). These calculations confirm the electrostatic nature of the interaction forces. A small amount of cyanoacetylene is incorporated into the bulk and desorbs at the onset of the ice crystallization near 145 K. In these two kinds of experiments, HC3N acts as both an electrophilic and a nucleophilic molecule.

17.
J Cell Physiol ; 189(1): 34-44, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11573202

RESUMO

It has been recently reported that retinoblastoma family proteins suppress cell growth by regulating not only E2F-dependent mRNA transcription but also rRNA and tRNA transcription and, through HDAC1 recruitment, chromatin packaging. In the present study we report data showing that these various control strategies are correlated, at least in part, with nuclear compartmentalization of retinoblastoma proteins. In a first series of experiments, we showed that pRb2/p130 and p107 are not evenly distributed within the nucleus and that cell cycle-dependent binding with E2F4 changes also as a function of their subnuclear localization. Namely, in the nucleoplasm pRb2/p130-E2F4 complexes are more numerous during G0/G1 while in the nucleolus they increase in S phase. Partially different functions for p107 are suggested since p107-E2F4 complexes in the nucleoplasm are more numerous is S phase with respect to G0/G1 and no cell cycle change is observed in the nucleolus. In a second series of experiments we showed that pRb2/p130, p107, E2F4, and pRb2/p130-HDAC1 complexes are all inner nuclear matrix-associated proteins and localize to sites different from pRb/p105 ones. We provide further evidence of multiple and partially distinct retinoblastoma protein family functional roles during cell cycle. Moreover, our data support emerging evidence for functional interrelationships between nuclear structure and gene expression.


Assuntos
Núcleo Celular/metabolismo , Proteínas Nucleares/fisiologia , Fosfoproteínas/fisiologia , Proteínas , Compartimento Celular , Ciclo Celular , Divisão Celular , Núcleo Celular/ultraestrutura , Proteínas de Ligação a DNA/imunologia , Proteínas de Ligação a DNA/metabolismo , Fator de Transcrição E2F4 , Histona Desacetilase 1 , Histona Desacetilases/imunologia , Histona Desacetilases/metabolismo , Humanos , Substâncias Macromoleculares , Microscopia Imunoeletrônica , Modelos Biológicos , Matriz Nuclear/metabolismo , Fosfoproteínas/imunologia , Proteína p107 Retinoblastoma-Like , Proteína p130 Retinoblastoma-Like , Fatores de Transcrição/imunologia , Fatores de Transcrição/metabolismo , Células Tumorais Cultivadas
18.
Org Lett ; 3(16): 2501-4, 2001 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-11483045

RESUMO

[reaction: see text] 2,5-Disubstituted oxazoles have been prepared through the reaction of N-propargylamides with aryl iodides in the presence of Pd(2)(dba)(3), tri(2-furyl)phosphine, and NaO(t)()Bu. The reaction appears to proceed through a palladium-catalyzed coupling step followed by the in situ cyclization of the resultant coupling product.


Assuntos
Amidas/síntese química , Oxazóis/síntese química , Pargilina/análogos & derivados , Pargilina/síntese química , Catálise , Ciclização , Indicadores e Reagentes , Paládio/química , Solventes
19.
Enzyme Microb Technol ; 28(6): 510-514, 2001 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-11267645

RESUMO

Effective diffusion coefficients (D(e)) of antibiotic A40926 and its deacylated derivative were determined in Ca-alginate (2% wt/wt) and kappa-carrageenan (2.6% wt/wt) gel beads with or without immobilized Actinoplanes teichomyceticus cells and/or soybean meal (SBM). The method used was based on transient concentration changes in a well-stirred antibiotic solution in which gel beads, initially free of solute, were suspended. Unsteady-state diffusion in a sphere was applied and D(e) determined from the best fit of experimental data. A40926 showed markedly different diffusion characteristics than its deacylated derivative. Diffusivity of deacyl-A40926 in alginate or carrageenan gel beads was six to seven times that of A40926. Large differences in partition coefficients (Kp) were also found. In case of beads without additions, A40926, in contrast to deacyl-A40926, strongly partitioned to the liquid phase. Introduction of SBM and/or mycelium in the gel beads decreased the effective diffusivity of deacyl-A40926, but increased its partitioning to the solid phase. Our findings indicate that a relatively moderate structural change of a lipoglycopeptide molecule could lead to a major change in its diffusion/partition characteristics.

20.
Antonie Van Leeuwenhoek ; 79(3-4): 399-405, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11816986

RESUMO

A literature survey covering more than twenty-three thousand bioactive microbial products including eight thousand antiinfectives demonstrated the increasing relevance of the so called 'rare' actinomycetes as a source of new antibiotics. Past and present efforts in the isolation of rare actinomycetes have enriched the Biosearch Italia Strain Collection with more than twenty thousand strains, showing that, when selective isolation methods are developed and extensively applied, some genera, such as Actinomadura, Actinoplanes, Micromonospora, Microtetraspora, are not rare at all and can be recovered from many soil samples. The current focus is on the isolation of members of Streptosporangiaceae family, given their promising chemical diversity.


Assuntos
Actinomycetales/classificação , Actinomycetales/metabolismo , Antibacterianos/biossíntese , Actinomycetales/genética , Antibacterianos/química , Bases de Dados Factuais , Variação Genética , Especificidade da Espécie
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