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1.
Ann Ig ; 25(5): 377-87, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24048176

RESUMO

BACKGROUND: Oral and poster presentations at congresses are essential to spread scientific knowledge among the medical community. Many scientific societies have analyzed the quality of papers presented at their meetings but no information on abstracts' evaluation has been presented in Public Health field. DESIGN AND METHODS: This study aims to examine the quality of abstracts presented at annual meetings of Italian Public Health Society (SItI) in the period 2005-2010 through a validated checklist grid, evaluating eight dimensions: Inherency, Structure, Originality, Objectives, Study design, Sources, Results, Conclusions. Each item was scored from 0 to 3 points (max score: 24) and we used the average score in our study (15) as threshold of good quality. A multivariate analysis was performed in order to investigate predictors of score of abstracts presented. RESULTS: A total of 4,399 abstracts (1,172 oral communications, 3,227 posters) was examined. Around 60% were submitted by Universities and around 40% were from Central Italy. The highest quality was found in the fields of Vaccines (average score 18.9), Infectious Diseases (18) and in abstracts submitted by Universities (16.4). Predictors of lower quality identified were geographical area and affiliation (p= 0.002). Abstracts containing well-written Results, Conclusions and Objectives (3 points) were more likely to be of high quality(OR=55.6, OR=41.9, and OR=157.4; p>0.001) CONCLUSIONS: This is the first European study evaluating the quality of abstracts in the public health field. A reliable evaluation tool is fundamental to offer a transparent methodology of assessment and to improve the quality of research.


Assuntos
Indexação e Redação de Resumos/normas , Congressos como Assunto , Saúde Pública , Lista de Checagem , Coleta de Dados , Bases de Dados Bibliográficas , Estudos de Avaliação como Assunto , Itália , Variações Dependentes do Observador , Projetos Piloto , Controle de Qualidade , Melhoria de Qualidade
2.
Ann Ig ; 23(4): 283-94, 2011.
Artigo em Italiano | MEDLINE | ID: mdl-22026231

RESUMO

A cross-sectional, multicenter study was carried out in 6 Italian cities (Cassino, Chieti, Naples, Rome, Siena, Turin) in order to highlight differences in Web use to find out health information and its related consequences on behavioral choices and to describe the distribution of the phenomenon in Italy. Data were collected from October 2009 to September 2010 on a sample of volunteers recruited from laboratory analysis, with face-to-face interview, including information about socio-demographic, health, and Web use to health. Data analysis shows that e-health use is greater in Northern Italy, in women aged 30-41 years, in chronic patients and those who have been caught up medical malpractice. Behavioral changes are associated with the Region; in particular Rome and Cassino show to choose/change professionals and facilities, engaging in alternative therapies and buy drugs online more frequently. Living in Southern Italy, a lower educational level and the infrequent drugs use are associated with a greater probability of incurring in negative behaviors. Positive results on the behavior are instead low and not significant. Given the regional differences, the potentiality and the risks of e-health use, it will be important to identify strategies for risks containment and implementation of the web in prevention.


Assuntos
Comportamento de Escolha , Comportamentos Relacionados com a Saúde , Internet , Adolescente , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , População Urbana , Adulto Jovem
3.
Food Chem ; 338: 127840, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32822903

RESUMO

In bottled wines, haze and turbidity are phenomena to be avoided. Since bentonite fining is a common process to clarify wines removing heat unstable proteins, a theoretical study on the adsorption of three Charged Model Molecules (CMMs, egg albumin, polyphenols and riboflavin) was carried out to deep comprehend this chemical phenomenon. Four bentonites were adopted and finely characterized together with the potential release of Na+ and Ca2+ cations, revealing suitable for RT albumin removal within 120 min. Better results in terms of adsorbed quantity were achieved by adopting 12%v/v EtOH/H2O solvent and by swelling bentonites for 24 h before use. With the most performing sample (Na/Ca_0.27), a comprehensive study on simultaneous adsorption of the three CMMs was performed, resulting in polyphenols adsorption increase due to their interactions with albumin. Notwithstanding the majority of albumin and riboflavin was successfully removed, ca. 40-50% of tested polyphenols was preserved.


Assuntos
Bentonita/química , Vinho/análise , Adsorção , Cálcio/química , Cálcio/metabolismo , Cromatografia Líquida de Alta Pressão , Cinética , Espectrometria de Massas , Ovalbumina/química , Polifenóis/química , Riboflavina/química , Sódio/química , Sódio/metabolismo
4.
Ann Ig ; 22(2): 147-55, 2010.
Artigo em Italiano | MEDLINE | ID: mdl-20476654

RESUMO

The scientific literature on HIA is particularly rich in Anglo-Saxon countries (United Kingdom, Canada, New Zealand), in Sweden and in the Netherlands, while in Italy there are not many scientific studies published on this theme. The study conducted showed that in Italy no laws relating to HIA have been enacted yet and that all laws enacted so far considered only EIA. Actually, legislation on environmental impact is in continuous expansion, even if at present, some regions have not yet passed a specified EIA-dealing law. In Italy the protection of health is promoted almost exclusively at a strictly medical level; decisions with strong social and environmental impact are not normally designed with particular regard to health issues. To increase in our country the interest for HIA, it would seem appropriate to discuss the usefulness of introducing health impact assessment in national and regional legislation. A possible law may indeed sensitize non-health decision makers to HIA, bringing Italy among the most innovative countries.


Assuntos
Meio Ambiente , Saúde Pública/legislação & jurisprudência , Humanos , Itália
6.
G Ital Med Lav Ergon ; 28(1 Suppl): 84-7, 2006.
Artigo em Italiano | MEDLINE | ID: mdl-16711118

RESUMO

With this presentation it will be introduced the experience of the work group native of Bergamo who is taken care to plan the formation course for the professional figures of system in building. The group is formed from the greater agencies present on the territory, their work is to ensure the protection of the health and the emergency of the workers in the field of the constructions. The objective is to use the formation course in order to diffuse one culture of the emergency. In the specific one they will come to describe the various planning phases of the course of formation for employers that mean to elect himself Responsible of the Service of Prevention and Protection (RSPP).


Assuntos
Indústrias/educação , Humanos , Itália , Saúde Ocupacional
7.
Biochim Biophys Acta ; 959(1): 9-19, 1988 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-3278744

RESUMO

The ability of some azasqualene derivatives to inhibit yeast cell growth was compared with their inhibition activity on squalene-2,3-oxide cyclase (EC 5.4.99.7) both in living cells and in microsome preparations. Among the compounds tested, N,N-diethylazasqualene showed the best correlation between the activity on squalene-2,3-oxide cyclase and its inhibition of yeast growth. The N-oxide derivative, N,N-diethylazasqualene N-oxide, which was as active as the amine in microsomes, was much less active in living cells, probably because it could not easily penetrate the cell wall. Kinetic analysis of the inhibitory activity of compounds on squalene-2,3-oxide cyclase revealed a sharp difference between N,N-diethylazasqualene and its N-oxide; the former showed a non-competitive-type inhibition, whereas the latter behaved as a competitive inhibitor.


Assuntos
Compostos Aza/farmacologia , Transferases Intramoleculares , Isomerases/antagonistas & inibidores , Saccharomyces cerevisiae/metabolismo , Esqualeno/análogos & derivados , Esteróis/biossíntese , Cinética , Microssomos/enzimologia , Saccharomyces cerevisiae/efeitos dos fármacos , Esqualeno/farmacologia
8.
FEBS Lett ; 320(3): 203-6, 1993 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-8462686

RESUMO

Inhibitory properties of 6E (compound 1) and 6Z (compound 2) isomers of 2,3-epoxy-10-aza-10,11-dihydrosqualene against oxidosqualene-lanosterol cyclase were assayed on microsomes and whole cells of Saccharomyces cerevisiae and Candida albicans. Only the 6E isomer (compound 1), bearing a correct substrate-like configuration, strongly inhibited the enzyme both in microsomes and cell cultures. The difference between compounds 1 and 2 (which had an unfavorable geometry) was especially evident when measuring [14C]acetate incorporation into non-saponifiable lipids extracted from treated cells. While isomer Z was totally ineffective at up to 30 microM, in cells treated with 5 microM isomer E, labelled oxidosqualene, the level of which was negligible in the control, rose to over 60% of the non-saponifiable lipids.


Assuntos
Compostos de Epóxi/farmacologia , Transferases Intramoleculares , Isomerases/antagonistas & inibidores , Saccharomyces cerevisiae/enzimologia , Esqualeno/análogos & derivados , Candida albicans/enzimologia , Divisão Celular/efeitos dos fármacos , Metabolismo dos Lipídeos , Microssomos/enzimologia , Esqualeno/farmacologia , Estereoisomerismo
9.
J Med Chem ; 35(16): 3050-8, 1992 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-1501233

RESUMO

2,3-Epoxy-10-aza-10,11-dihydrosqualene, a high-energy intermediate analogue inhibitor of 2,3-oxidosqualene (SO) cyclase was obtained by total synthesis. This involved the preparation of three main building blocks: (1) C17 squalenoid N-methylamine, (2) 3-(diphenylphosphinoyl)propanal, and (3) 5,6-epoxy-6-methylheptan-2-one. The final stages of the reconstruction of the 6E double bond were obtained by a Wittig-Horner reaction which was modified for poorly reactive systems. This compound was designed to mimic the C-8 carbonium ion formed during SO cyclization. Its inhibitory activity on various SO cyclases was evaluated and compared with the 6 Z isomer which has an unfavorable geometry. Only isomer 6 E, the carbocation analogue, was active on SO cyclases from rat liver, pig liver, S. cerevisiae, and C. albicans microsomes, with an I50 varying from 3 to 5 microM. Both E and Z isomers were inactive on squalene epoxidase at the higher concentrations tested.


Assuntos
Compostos de Epóxi/farmacologia , Transferases Intramoleculares , Isomerases/antagonistas & inibidores , Esqualeno/análogos & derivados , Animais , Candida albicans/enzimologia , Compostos de Epóxi/química , Espectroscopia de Ressonância Magnética , Microssomos Hepáticos/enzimologia , Ratos , Saccharomyces cerevisiae/enzimologia , Esqualeno/química , Esqualeno/farmacologia , Suínos
10.
J Med Chem ; 41(4): 540-54, 1998 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-9484504

RESUMO

Two pairs of isomers (18Z)- (8), (18E)-29-methylidene-2,3-oxidohexanorsqualene (21), and (18Z)- (31), (18E)-29-methylidene-2,3-oxidosqualene (34), have been obtained in a fully stereospecific manner, as inhibitors of rat and yeast oxidosqualene cyclase. A new method for the synthesis of C22 squalene aldehyde 2,3-epoxide is reported, as well as that of other 19-modified 2,3-oxidosqualene analogues. We found that the activity is the opposite in the two series: the (E)-hexanormethylidene 21 and the (Z)-methylidene 31 are potent and irreversible inhibitors of oxidosqualene cyclase, while (Z)-hexanormethylidene 8 and (E)-methylidene 34 are almost completely inactive. Reduction of the 18,19-double bond, such as in 39, eliminates the activity, while removal of both of the 19-linked groups such as in heptanor derivative 40 greatly reduces inhibition of the enzyme. (E)-Hexanormethylidene 21 results the first irreversible inhibitor of the series toward the yeast enzyme.


Assuntos
Inibidores Enzimáticos/síntese química , Transferases Intramoleculares/antagonistas & inibidores , Microssomos Hepáticos/enzimologia , Saccharomyces cerevisiae/enzimologia , Esqualeno/análogos & derivados , Esqualeno/síntese química , Animais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Transferases Intramoleculares/isolamento & purificação , Cinética , Microssomos/enzimologia , Modelos Moleculares , Conformação Molecular , Ratos , Esqualeno/química , Esqualeno/farmacologia , Relação Estrutura-Atividade , Suínos
11.
Biochem Pharmacol ; 38(15): 2497-503, 1989 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-2757649

RESUMO

The metabolism of squalene dimethylamine (I), a potent inhibitor of 2,3-oxidosqualene (SO) cyclase, and of sixteen other squalene derivatives was investigated in rat liver microsomes. N-oxidation was the only metabolic pathway observed, squalene dimethylamine N-oxide being the only metabolite isolated from incubation of I. The azasqualane and quaternary ammonium derivatives did not form N-oxides during their metabolism. The inhibition of aminopyrine N-demethylase activity was also studied and the IC50, for compound I, which shows weak competitive inhibition, was determined. At 1 mM concentration the other squalene derivatives showed a range of inhibition activity possibly due to their different lipophilicity.


Assuntos
Aminopirina N-Desmetilase/metabolismo , Compostos Aza/metabolismo , Microssomos Hepáticos/metabolismo , Esqualeno/análogos & derivados , Aminopirina N-Desmetilase/antagonistas & inibidores , Animais , Compostos Aza/farmacologia , Inibidores das Enzimas do Citocromo P-450 , Técnicas In Vitro , Masculino , Oxirredução , Ratos , Ratos Endogâmicos , Esqualeno/metabolismo , Esqualeno/farmacologia
12.
Biochem Pharmacol ; 50(6): 787-96, 1995 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-7575639

RESUMO

The inhibition of 2,3-oxidosqualene-lanosterol cyclase (EC 5.4.99.7) (OSC) by new azasqualene derivatives, mimicking the proC-8 and proC-20 carbocationic high-energy intermediates of the cyclization of 2,3-oxidosqualene to lanosterol, was studied using pig liver microsomes, partially purified preparations of OSC, and yeast microsomes. The azasqualene derivatives tested were: 6E- and 6Z-10aza-10,11-dihydrosqualene-2,3-epoxide 17 and 18, 19-aza-18,19,22,23-tetrahydrosqualene-2,3-epoxide 19 and its corresponding N-oxide 20, and 19-aza-18,19,22,23-tetrahydrosqualene 21. The compounds 17 and 19 (i.e. the derivatives bearing the 2,3-epoxide ring and the same geometrical configuration as the OSC substrate) were effective inhibitors, as shown by the Ki obtained using partially purified OSC: 2.67 microM and 2.14 microM, respectively. Compound 18, having an incorrect configuration and the 19-aza derivative 21, lacking the 2,3-epoxide ring, were poor inhibitors, with IC50 of 44 microM and 70 microM, respectively. Compound 21 was a competitive inhibitor of OSC, whereas 17 and 19 were noncompetitive inhibitors, and showed a biphasic time-dependent inactivation of OSC, their apparent binding constants being 250 microM and 213 microM, respectively. The inhibition of sterol biosynthesis was studied using human hepatoma HepG2 cells. The incorporation of [14C] acetate in the C27 sterols was reduced by 50% by 0.55 microM 17, 0.22 microM 19, and 0.45 microM 21, whereas 2 microM 18 did not affect sterol biosynthesis. In the presence of 17, 19 and 21, only the intermediate metabolites 2,3-oxidosqualene and 2,3,22,23-dioxidosqualene accumulated, demonstrating a very specific inhibition of OSC.


Assuntos
Compostos de Epóxi/farmacologia , Transferases Intramoleculares , Isomerases/antagonistas & inibidores , Esqualeno/análogos & derivados , Esteróis/biossíntese , Animais , Humanos , Cinética , Microssomos Hepáticos/enzimologia , Ratos , Esqualeno/metabolismo , Esqualeno/farmacologia , Estereoisomerismo , Suínos , Células Tumorais Cultivadas
13.
Biochem Pharmacol ; 52(1): 157-66, 1996 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-8678901

RESUMO

Site-selective toxin delivery was achieved by coupling monoclonal antibody to the A chain subunit of ricin (RTA-IT). The cell-killing potency of RTA-IT can be drastically increased in vitro by using ionophores such as monensin. To reduce the intrinsic toxicity of monensin and to enhance its in vitro and in vivo activity, we synthesized 7 derivatives characterized by different lipophilicities. These derivatives were also analyzed for ionophoretic activity on intact cells, toxicity, and RTA-IT-enhancing activity. Two different RTA-IT were assayed on a human leukemia cell line. A correlation between lipophilicity, ionophoretic activity, and RTA-IT enhancement was observed. The compounds with the highest polar charge showed low intrinsic toxicity, revealed moderate ionophoretic activity, and were able to enhance RTA-IT only at high concentrations, whereas more lipophilic compounds (with a C28 tail or a phenyl group) showed significant ionophoretic activity and good enhancing properties.


Assuntos
Imunotoxinas/farmacologia , Ionóforos/farmacologia , Monensin/farmacologia , Ricina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Monensin/química , Ricina/química , Células Tumorais Cultivadas
14.
J Control Release ; 63(1-2): 19-30, 2000 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-10640577

RESUMO

Paclitaxel (Taxol) is a diterpenoid isolated from Taxus brevifolia, approved by the FDA for the treatment of ovarian and breast cancers. Due to its low solubility in water, it is clinically administered dissolved in Cremophor EL, (polyethoxylated castor oil) and ethanol, which cause serious side effects. Inclusion of paclitaxel in liposomal formulations has proved to be a good approach to eliminating this vehicle and improving the drug's antitumor efficacy. We prepared different conventional and PEGylated liposomes containing paclitaxel and determined encapsulation efficiency, physical stability and drug leakage in human plasma. The best conventional liposome formulation was composed of ePC/PG 9:1, while for PEGylated liposomes the best composition was ePC/PG/CHOL/PEG(5000)-DPPE 9:1:2:0.7. PEGylated liposomes were found to be less stable during storage than the corresponding conventional liposomes and to have lower drug release in human plasma at 37 degrees C. In vitro cytotoxic activities were evaluated on HT-29 human colon adenocarcinoma and MeWo melanoma cell lines. After 2 and 48 h, conventional liposomes had the same cytotoxicity as free paclitaxel, while PEGylated liposomes were as active as free drug, only after 48 h. Pharmacokinetics and biodistribution were evaluated in Balb/c mice after i.v. injection of paclitaxel, formulated in Cremophor EL or in conventional or in PEGylated liposomes. Encapsulation of paclitaxel in conventional liposomes produced marked differences over the free drug pharmacokinetics. PEGylated liposomes were long-circulating liposomes, with an increased t(1/2) beta 48.6 h, against t(1/2) beta 9.27 h of conventional liposomes. Biodistribution studies showed a considerable decrease in drug uptake in MPS-containing organs (liver and spleen) at 0.5 and 3 h after injection with PEGylated compared to conventional liposomes.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacocinética , Paclitaxel/administração & dosagem , Paclitaxel/farmacocinética , Animais , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/toxicidade , Colesterol/administração & dosagem , Colesterol/química , Portadores de Fármacos , Feminino , Células HT29/efeitos dos fármacos , Humanos , Lipossomos/toxicidade , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Paclitaxel/química , Paclitaxel/toxicidade , Fosfatidilcolinas/administração & dosagem , Fosfatidilcolinas/química , Fosfatidiletanolaminas/administração & dosagem , Fosfatidiletanolaminas/química , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/química , Succinimidas/administração & dosagem , Succinimidas/química , Distribuição Tecidual , Células Tumorais Cultivadas
15.
J Control Release ; 63(1-2): 141-53, 2000 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-10640588

RESUMO

Paclitaxel (Taxol) is a diterpenoid isolated from Taxus brevifolia, used clinically for the treatment of ovarian and breast cancer. Due to its aqueous insolubility it is administered dissolved in ethanol and Cremophor EL (polyethoxylated castor oil), which has serious side effects. In order to eliminate this vehicle, in previous work we entrapped paclitaxel in conventional and in polyethylene glycol coated liposomes. However, in neither formulation did we obtain satisfactory entrapment efficiency. In this study we increased the paclitaxel concentration entrapped in liposomes by incorporating different water-soluble prodrugs, such as the 2'-succinyl, 2'-methylpyridinium acetate and 2'-mPEG ester paclitaxel derivatives, in the lipid vesicles. Liposomes containing 2'-mPEG (5000)-paclitaxel showed the best performance in terms of stability, entrapment efficiency and drug concentration (6.5 mgml(-1)). The in vitro cytotoxic activity of this liposomal prodrug was similar to that of the parent drug. The pharmacokinetic parameters for the free and for the liposomal prodrugs fitted a bi-exponential plasma disposition. The most important change in pharmacokinetic values of the prodrug vs. the free drug liposomal formulations was t(1/2)beta, plasma lifetime, which was longer in liposomes containing 2'-mPEG (5000)-paclitaxel.


Assuntos
Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/toxicidade , Paclitaxel/farmacocinética , Paclitaxel/toxicidade , Pró-Fármacos/síntese química , Pró-Fármacos/toxicidade , 1,2-Dipalmitoilfosfatidilcolina/administração & dosagem , 1,2-Dipalmitoilfosfatidilcolina/química , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacocinética , Colesterol/administração & dosagem , Colesterol/química , Portadores de Fármacos , Estabilidade de Medicamentos , Feminino , Células HT29 , Humanos , Lipossomos , Camundongos , Camundongos Endogâmicos BALB C , Paclitaxel/administração & dosagem , Fosfolipídeos/administração & dosagem , Fosfolipídeos/química , Pró-Fármacos/administração & dosagem , Pró-Fármacos/farmacocinética , Solubilidade , Células Tumorais Cultivadas , Água/química
16.
Chem Phys Lipids ; 70(1): 21-34, 1994 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-8013054

RESUMO

Various squalene derivatives, including squalene, squalene 2,3-epoxide (monoepoxide, SQME), squalene 2,3;22,23-diepoxide (SQDE), 2-aza-2,3-dihydrosqualene (SQN) and 2-aza-2,3-dihydrosqualene N-oxide (SQNO), were studied in chloroform solutions using ID high-resolution 1H spectra and 13C longitudinal relaxation studies, 2D proton NOESY and COSY and 2D proton-carbon HETCOR spectroscopy. A full interpretation of the 1H and 13C-NMR spectra is presented. Staggered conformations along the C11-C12 bond are favoured and a relatively rigid structure of the central part of the chain is indicated in relaxation and coupling data, while further away from the central part the molecular mobility grows. A detected NOE dipolar interaction between terminal and central parts of the molecule indicates the presence of dynamically folded structures in solution. The proposed model also explains the selective reactivity of the mobile chain endings with respect to the central part which is protected by these moving ends. Different solvents at different concentrations induce some variations in this molecular model with a shortening or a lengthening of the mean path covered by the tail endings. Molecular mechanics and molecular dynamics calculations on the free squalene molecule indicate that the mobility of the chain is almost equivalent in all its isoprenic moieties, and the greater mobility of the chain ends may be ascribed to co-operative movements from the center to the tails. The solvent probably plays an important role in hindering the motion of the central part of the molecule.


Assuntos
Esqualeno/química , Isótopos de Carbono , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Prótons , Esqualeno/análogos & derivados
17.
Steroids ; 53(3-5): 363-91, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2678608

RESUMO

Various classes of inhibitor of 2,3-oxido squalene cyclase have been synthesized and tested on rat liver and Saccharomyces cerevisiae microsomes, 3T3 fibroblast cultures, and various bacteria, fungi, and yeasts. The compounds include azasqualenes, azasqualanes, bis-azasqualenes, bis-azasqualanes, and N-oxide and ammonium derivatives of squalene. In order to better mimic the transition state involved in the SN2-like opening of 2,3-oxidosqualene, we synthesized squalene N-methyloxaziridine. Other derivatives tested were N-methylimine, aminalic hydroperoxide, and N-methylamide. We also attempted to produce new "suicide" inhibitors of SO cyclase, such as a squalenoid epoxide vinyl ether. Many of the products described inhibited the various cyclases, the best having an IC50 of 0.3 microM on plants and 1.5 microM on rat liver microsomes, and good antibacterial and antifungal activity. In a search for inhibitors of squalene epoxidase, a series of mono- and bifunctional squalenoid acetylenes and allenes were synthesized. Some of them proved to be inhibitors of squalene epoxidase.


Assuntos
Desenho de Fármacos , Transferases Intramoleculares , Isomerases/antagonistas & inibidores , Oxigenases/antagonistas & inibidores , Alcinos , Animais , Anticolesterolemiantes/farmacologia , Antifúngicos/farmacologia , Ligação Competitiva , Cinética , Microssomos Hepáticos/metabolismo , Ratos , Saccharomyces cerevisiae/metabolismo , Esqualeno/análogos & derivados , Esqualeno/síntese química , Esqualeno Mono-Oxigenase
18.
Anticancer Res ; 21(3C): 2243-8, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11501854

RESUMO

BACKGROUND: The kinetics of melphalan leakage from extracorporeal fluid to the peripheral blood was studied in ten patients undergoing hyperthermic isolation perfusion of the lower limbs as an adjuvant treatment in high-risk melanoma. MATERIALS AND METHODS: Systemic leakage was monitored by a new technique using 99mTc-albumin microcolloid. Serial samples were drawn from a peripheral vein and from the perfusion circuit during surgical treatment and analysed by HPLC. RESULTS: The leakage measured with 99mTc-albumin microcolloid ranged from 1.5 to 18%/h (mean 8%/h). The average concentrations in the perfusate were 200-300-fold those found in the systemic circulation. A good correlation (R=0.945) was obtained between systemic AUC (0 to 1 hour) and leakage measured through the 99mTc procedure. Negligible toxicity was found and the survival rate yielded 92% of objective response. CONCLUSION: By studying the pharmacokinetic data of melphalan in the circuit and in the systemic circulation, we were able to validate the 99mTc procedure used during clinical perfusion. Moreover, considering the efficiency of the system as well as the minimum toxicity and the high survival rate, a reduction of perfusion time may be considered.


Assuntos
Antineoplásicos Alquilantes/farmacocinética , Quimioterapia do Câncer por Perfusão Regional/métodos , Hipertermia Induzida , Melanoma/metabolismo , Melfalan/farmacocinética , Compostos Radiofarmacêuticos , Agregado de Albumina Marcado com Tecnécio Tc 99m , Idoso , Antineoplásicos Alquilantes/administração & dosagem , Coloides/farmacocinética , Terapia Combinada , Monitoramento de Medicamentos/métodos , Estabilidade de Medicamentos , Extravasamento de Materiais Terapêuticos e Diagnósticos/metabolismo , Feminino , Humanos , Fígado/metabolismo , Masculino , Melanoma/tratamento farmacológico , Melanoma/terapia , Melfalan/administração & dosagem , Pessoa de Meia-Idade , Compostos Radiofarmacêuticos/farmacocinética , Agregado de Albumina Marcado com Tecnécio Tc 99m/farmacocinética
19.
J Pharm Sci ; 82(5): 506-12, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-8360828

RESUMO

In an effort to obtain a more potent and specific immunotoxin for cancer therapy, we designed a series of heterobifunctional linkers characterized by a thioimidate group linked to a S-acetyl thiol (4, 5) or substituted aryldithio group (6-10). These ligands were synthesized by a Pinner-type process from the corresponding nitrile derivatives obtained by thiol-disulphide exchange reaction, reaction with substituted benzene-sulphenyl chloride, or other known procedures. To check the reagent of choice for immunoconjugate preparation, we studied thioldisulphide exchange kinetics between the intermediate nitrile derivatives and cysteine. Among the tested aryldithio derivatives (6-10), we selected ethyl 3-(4-carboxamido-phenyldithio)propionthioimidate (CDPT, 9) for further studies. By analyzing the rate of incorporation of the linkers 4, 5, and 9 in a model immunoglobulin G protein, we found similar results with CDPT 9 and ethyl S-acetyl 3-mercaptopropionthioimidate ester hydrochloride (AMPT, 5) because both reagents showed a linear correlation between the number of introduced thiol groups and factors such as time and protein and reagent concentrations. Comparison of the two acetylthio-derivative ligands 4 and 5 showed that AMPT 5 was more stable toward deacetylation than ethyl S-acetyl 2-mercaptopropionthioimidate ester hydrochloride (AMAT, 4). By comparing the kinetic and biological parameters of seven new thioimidate linkers, we found that two of these (CDPT and AMPT) could be superior ligands for protein-protein conjugation. They offer advantages over the commercially available compounds, such as minimal perturbation of the protein structure, controlled reactivity, and good stability.


Assuntos
Reagentes de Ligações Cruzadas/síntese química , Imidoésteres/síntese química , Imunotoxinas/química , Animais , Bovinos , Remoção de Radical Alquila , Dissulfetos/síntese química , Dissulfetos/química , Concentração de Íons de Hidrogênio , Imidoésteres/química , Imunoglobulina G/química , Cinética , Oxirredução
20.
J Pharm Sci ; 82(7): 699-704, 1993 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8360843

RESUMO

To obtain more potent immunotoxins for anticancer therapy a gelonin-AR3 antibody immunoconjugate was prepared with different new linkers and coupling procedures. The gelonin was derivatized with the heterobifunctional thioimidate linkers ethyl-acetyl-3-mercaptopropionthioimidate (AMPT) and 3-(4-carboxamidophenyldithio)propionthioimidate (CDPT), and with the succinimidyl type reagents N-succinimidyl-3-(4-carboxamidophenyldithio)propionate (SCDP) and N-succinimidyl-S-acetyl thiolacetate (SATA). The biological activity of gelonin modified with different linkers (AMPT, CDPT, SCDP, SATA) was determined by a rabbit reticulocyte assay. We found that AMPT was the molecule of choice to derivatize the toxin, confirming the preferability of thioimidate linkers. The monoclonal antibody Mab was derivatized with CDPT and SCDP. Then the following immunoconjugates were prepared with different procedures: Mab-CDPT with gelonin-AMPT; Mab-CDPT with gelonin-CDPT; Mab-SCDP with gelonin-SATA. To verify whether selection of the most suitable coupling procedure could affect the antitumoral activity of the gelonin-AR3 immunoconjugate, the three immunotoxins were tested on target HT-29 human colon carcinoma cells versus nontarget MeWo cells. The gelonin immunoconjugate linked via the AMPT-CDPT thioimidate reagents showed highest antitumoral activity as well as best selectivity for the target cells.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Imunotoxinas/farmacologia , Proteínas de Plantas/química , Inibidores da Síntese de Proteínas/química , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/farmacologia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/química , Sistema Livre de Células , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Reagentes de Ligações Cruzadas , Humanos , Imunotoxinas/química , Camundongos , Proteínas de Plantas/farmacologia , Biossíntese de Proteínas , Inibidores da Síntese de Proteínas/farmacologia , Coelhos , Reticulócitos/efeitos dos fármacos , Proteínas Inativadoras de Ribossomos Tipo 1 , Células Tumorais Cultivadas
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