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1.
Eur J Intern Med ; 77: 79-85, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32151490

RESUMO

BACKGROUND: An abnormal ankle-brachial pressure index (ABI) is a marker of the risk for increased total and cardiovascular (CV) mortality. However, it is not clear whether it is associated with an even worse prognosis in patients with previous CV events or with cancer mortality. MATERIALS AND METHODS: Consecutive subjects undergoing ABI assessment for suspected peripheral artery disease or for stratification of CV risk in ten centers in the Veneto Region (northeast Italy), between 2011 and 2014 were enrolled. The ABI was expressed as normal ≥0.9 to ≤1.3, and abnormal <0.9 or >1.3. All-cause mortality and CV or cancer mortality and hospitalizations for CV disease were collected from administrative databases up to December 2018. RESULTS: The study enrolled 1,177 patients. ABI was abnormal in 57.2%. Median follow-up was 61.6 months (53.4-70.1). All-cause, CV and cancer mortality were higher in patients with abnormal than normal ABI, with hazard ratios (HR) respectively 2.0 (95% CI 1.48-2.69), 1.98 (95% CI 1.24-3.17) and 1.85 (95% CI 1.09-3.15). Among subjects with abnormal ABI, the risk of overall mortality, HR 1.57 (95% CI 1.17-2.12), and CV mortality, HR 2.39 (95% CI 1.43-3.99), was higher in those with previous CV events. These latter also had a higher risk of hospitalization for myocardial infarction and stroke: HR 1.85 (95% CI 1.023.37) and 2.17 (95% CI 1.10-4.28). CONCLUSIONS: The co-existence of abnormal ABI and a history of CV events identifies subjects at higher risk, who call for a more aggressive approach. Abnormal ABI is also a predictor of cancer mortality.


Assuntos
Doenças Cardiovasculares , Neoplasias , Índice Tornozelo-Braço , Fatores de Risco de Doenças Cardíacas , Humanos , Itália/epidemiologia , Valor Preditivo dos Testes , Prognóstico , Fatores de Risco
2.
Braz J Med Biol Res ; 43(12): 1193-202, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21140097

RESUMO

The objective of this study was to determine the effect of eight 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-carboxyamidepyrazoles (TFDPs) on rat body temperature and baker's yeast-induced fever. TFDPs or vehicle (5% Tween 80 in 0.9% NaCl, 5 mL/kg) were injected subcutaneously and rectal temperature was measured as a function of time in 28-day-old male Wistar rats (N = 5-12 per group). Antipyretic activity was determined in feverish animals injected with baker's yeast (Saccharomyces cerevisiae suspension, 0.135 mg/kg, 10 mL/kg, ip). 3-Ethyl- and 3-propyl-TFDP (140 and 200 µmol/kg, respectively, 4 h after yeast injection) attenuated baker's yeast-induced fever by 61 and 82%, respectively. These two effective antipyretics were selected for subsequent analysis of putative mechanisms of action. We then determined the effects on cyclooxygenase-1 and -2 (COX-1 and COX-2) activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) oxidation in vitro, on tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) levels and on leukocyte counts in the washes of peritoneal cavities of rats injected with baker's yeast. While 3-ethyl- and 3-propyl-TFDP did not reduce baker's yeast-induced increases of IL-1ß or TNF-α levels, 3-ethyl-TFDP caused a 42% reduction in peritoneal leukocyte count. 3-Ethyl- and 3-propyl-TFDP did not alter COX-1 or COX-2 activities in vitro, but presented antioxidant activity in the DPPH assay with an IC50 of 39 mM (25-62) and 163 mM (136-196), respectively. The data indicate that mechanisms of action of these two novel antipyretic pyrazole derivatives do not involve the classic inhibition of the COX pathway or pyrogenic cytokine release.


Assuntos
Antioxidantes/farmacologia , Antipiréticos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Pirazóis/farmacologia , Animais , Antipiréticos/química , Ciclo-Oxigenase 1/farmacologia , Ciclo-Oxigenase 2/farmacologia , Interleucina-1beta/efeitos dos fármacos , Interleucina-1beta/metabolismo , Masculino , Pirazóis/química , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
3.
Braz. j. med. biol. res ; 43(12): 1193-1202, Dec. 2010. ilus
Artigo em Inglês | LILACS | ID: lil-569003

RESUMO

The objective of this study was to determine the effect of eight 5-hydroxy-5-trifluoromethyl-4,5-dihydro-1H-1-carboxyamidepyrazoles (TFDPs) on rat body temperature and baker’s yeast-induced fever. TFDPs or vehicle (5 percent Tween 80 in 0.9 percent NaCl, 5 mL/kg) were injected subcutaneously and rectal temperature was measured as a function of time in 28-day-old male Wistar rats (N = 5-12 per group). Antipyretic activity was determined in feverish animals injected with baker’s yeast (Saccharomyces cerevisiae suspension, 0.135 mg/kg, 10 mL/kg, ip). 3-Ethyl- and 3-propyl-TFDP (140 and 200 μmol/kg, respectively, 4 h after yeast injection) attenuated baker’s yeast-induced fever by 61 and 82 percent, respectively. These two effective antipyretics were selected for subsequent analysis of putative mechanisms of action. We then determined the effects on cyclooxygenase-1 and -2 (COX-1 and COX-2) activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) oxidation in vitro, on tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels and on leukocyte counts in the washes of peritoneal cavities of rats injected with baker’s yeast. While 3-ethyl- and 3-propyl-TFDP did not reduce baker’s yeast-induced increases of IL-1β or TNF-α levels, 3-ethyl-TFDP caused a 42 percent reduction in peritoneal leukocyte count. 3-Ethyl- and 3-propyl-TFDP did not alter COX-1 or COX-2 activities in vitro, but presented antioxidant activity in the DPPH assay with an IC50 of 39 mM (25-62) and 163 mM (136-196), respectively. The data indicate that mechanisms of action of these two novel antipyretic pyrazole derivatives do not involve the classic inhibition of the COX pathway or pyrogenic cytokine release.


Assuntos
Animais , Masculino , Ratos , Antioxidantes/farmacologia , Antipiréticos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Pirazóis/farmacologia , Antipiréticos/química , Ciclo-Oxigenase 1/farmacologia , /farmacologia , Interleucina-1beta/efeitos dos fármacos , Interleucina-1beta/metabolismo , Pirazóis/química , Ratos Wistar , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
4.
Braz J Med Biol Res ; 39(6): 795-9, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16751986

RESUMO

The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 micromol/kg, s.c.) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 +/- 6.15; B50 (8 micromol/kg): 16.92 +/- 3.84; B50 (23 micromol/kg): 13.85 +/- 3.84; B50 (80 micromol/kg): 9.54 +/- 3.08; data are reported as means +/- SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 micromol/kg, s.c.) prevented B50-induced antinociception (number of writhes: vehicle-saline: 31.11 +/- 3.15; vehicle-naloxone: 27.41 +/- 3.70; B50 (80 micromol/kg)-saline: 8.70 +/- 3.33; B50 (80 micromol/kg)-naloxone: 31.84 +/- 4.26; morphine-saline: 2.04 +/- 3.52; morphine-naloxone: 21.11 +/- 4.26; 8-9 animals per group). The removal of the methyl group of the thiazole ring of B50 or substitution of the bromo substituent with the methyl at position 4 of the phenyl group, which is attached to the thiazole ring of B50, resulted in loss of activity, suggesting that these substituents are important for antinociceptive activity. B50 had no effect on spontaneous locomotion or rotarod performance, indicating that the antinociceptive effect of B50 is not related to nonspecific motor effects. The antinociceptive profile of B50 seems to be closer to nonsteroidal anti-inflammatory drugs than to classic opioid agents, since it had no analgesic effect in a thermally motivated test.


Assuntos
Analgésicos/farmacologia , Medição da Dor/efeitos dos fármacos , Pirazóis/farmacologia , Tiazóis/farmacologia , Ácido Acético , Animais , Relação Dose-Resposta a Droga , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Naloxona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Pirazóis/química , Tempo de Reação , Tiazóis/química
5.
Braz. j. med. biol. res ; 39(6): 795-799, June 2006. graf
Artigo em Inglês | LILACS | ID: lil-428270

RESUMO

The present study investigates the antinociceptive effect of the pyrazolyl-thiazole derivative 2-(5-trichloromethyl-5-hydroxy-3-phenyl-4,5-dihydro-1 H-pyrazol-1-yl)-4-(4-bromophenyl)-5-methylthiazole (B50) in mice. Male albino Swiss mice (30-40 g) were used in the acetic acid-induced abdominal writhes and tail-immersion tests. B50 caused dose-dependent antinociception (8, 23 and 80 µmol/kg, sc) in the acetic acid writhing assay (number of writhes: vehicle: 27.69 ± 6.15; B50 (8 µmol/kg): 16.92 ± 3.84; B50 (23 µmol/kg): 13.85 ± 3.84; B50 (80 µmol/kg): 9.54 ± 3.08; data are reported as means ± SEM for 9 animals per group). On the other hand, B50 did not cause antinociception in the tail immersion assay. Naloxone (2.75 µmol/kg, sc) prevented B50-induced antinociception (number of writhes: vehicle-saline: 31.11 ± 3.15; vehicle-naloxone: 27.41 ± 3.70; B50 (80 µmol/kg)-saline: 8.70 ± 3.33; B50 (80 µmol/kg)-naloxone: 31.84 ± 4.26; morphine-saline: 2.04 ± 3.52; morphine-naloxone: 21.11 ± 4.26; 8-9 animals per group). The removal of the methyl group of the thiazole ring of B50 or substitution of the bromo substituent with the methyl at position 4 of the phenyl group, which is attached to the thiazole ring of B50, resulted in loss of activity, suggesting that these substituents are important for antinociceptive activity. B50 had no effect on spontaneous locomotion or rotarod performance, indicating that the antinociceptive effect of B50 is not related to nonspecific motor effects. The antinociceptive profile of B50 seems to be closer to nonsteroidal anti-inflammatory drugs than to classic opioid agents, since it had no analgesic effect in a thermally motivated test.


Assuntos
Animais , Masculino , Camundongos , Analgésicos/farmacologia , Medição da Dor/efeitos dos fármacos , Pirazóis/farmacologia , Tiazóis/farmacologia , Ácido Acético , Relação Dose-Resposta a Droga , Atividade Motora/efeitos dos fármacos , Naloxona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Pirazóis/química , Tempo de Reação , Tiazóis/química
7.
J Inorg Biochem ; 99(9): 1853-7, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16098596

RESUMO

Long time ago aluminum (Al) was considered as a non-toxic element and its use had no restrictions. However, over the last two decades, scientific publications have indicated that Al is a toxic element. In line with this, aluminum accumulation in the organism is associated with a variety of human pathologies. Efficient therapeutics approach to treat Al intoxication are still not available, but there is a consensus that chelation therapy is the procedure to be used. However, the development of new chelating agents are highly desirable to improve the efficacy of the treatment of Al intoxication. The present study evaluates the chelating effect of two novel pyrimidines: 4-tricloromethyl-1-H-pyrimidin-2-one (THP) and (4-methyl-6-trifluoromethyl-6-pyrimidin-2-il)-hydrazine (MTPH) in a mice model of aluminum intoxication and compares their efficacy with those of desferrioxamine (DFO), a classical agent used for treat Al accumulation. The animals were exposed to aluminum by gavage (0.1 mmol aluminum/kg/day) 5 days/week for 4 weeks. At the end of this period, DFO was injected i.p. and the novel pyrimidines were given by gavage at 0.2 mmol/kg/day for five consecutive days. Aluminum concentration in tissues (brain, liver, kidney and blood) was determined by graphite furnace atomic absorption spectroscopy (GFAAS). The results showed that when administered by gavage, aluminum accumulated in the brain, kidney and liver of mice. MTPH was able to decrease aluminum levels in aluminum plus citrate animal groups, whereas THP was inefficient for this purpose. However, the novel pyrimidines used in this study were unable to surpass the aluminum chelating property of DFO. Thus, new studies must be performed utilizing other chelating agents which can decrease aluminum toxicity.


Assuntos
Alumínio/toxicidade , Quelantes/química , Modelos Químicos , Pirimidinas/química , Alumínio/química , Animais , Masculino , Camundongos
8.
Braz. j. med. biol. res ; 37(10): 1531-1540, Oct. 2004. tab, graf
Artigo em Inglês | LILACS | ID: lil-383035

RESUMO

The antinociceptive effect of six novel synthetic pyrazolines (3-ethoxymethyl-5-ethoxycarbonyl-1H-pyrazole (Pz 1) and its corresponding 1-substituted methyl (Pz 2) and phenyl (Pz 3) analogues, and 3-(1-ethoxyethyl)-5-ethoxycarbonyl-1H-pyrazole (Pz 4) and its corresponding 1-substituted methyl (Pz 5) and phenyl (Pz 6) analogues) was evaluated by the tail immersion test in adult male albino mice. The animals (N = 11-12 in each group) received vehicle (5 percent Tween 80, 10 ml/kg, sc) or 1.5 mmol/kg of each of the pyrazolines (Pz 1-Pz 6), sc. Fifteen, thirty and sixty minutes after drug administration, the mice were subjected to the tail immersion test. Thirty minutes after drug administration Pz 2 and Pz 3 increased tail withdrawal latency (vehicle = 3.4 ± 0.2; Pz 2 = 5.2 ± 0.4; Pz 3 = 5.9 ± 0.4 s; mean ± SEM), whereas the other pyrazolines did not present antinociceptive activity. Dose-effect curves (0.15 to 1.5 mmol/kg) were constructed for the bioactive pyrazolines. Pz 2 (1.5 mmol/kg, sc) impaired motor coordination in the rotarod and increased immobility in the open-field test. Pz 3 did not alter rotarod performance and spontaneous locomotion, but increased immobility in the open field at the dose of 1.5 mmol/kg. The involvement of opioid mechanisms in the pyrazoline-induced antinociception was investigated by pretreating the animals with naloxone (2.75 µmol/kg, sc). Naloxone prevented Pz 3- but not Pz 2-induced antinociception. Moreover, naloxone pretreatment did not alter Pz 3-induced immobility. We conclude that Pz 3-induced antinociception involves opioid mechanisms but this is not the case for Pz 2.


Assuntos
Animais , Masculino , Camundongos , Analgésicos , Medição da Dor , Pirazóis , Análise de Variância , Relação Dose-Resposta a Droga , Tempo de Reação , Receptores Opioides , Restrição Física
9.
Braz J Med Biol Res ; 37(10): 1531-40, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15448875

RESUMO

The antinociceptive effect of six novel synthetic pyrazolines (3-ethoxymethyl-5-ethoxycarbonyl-1H-pyrazole (Pz 1) and its corresponding 1-substituted methyl (Pz 2) and phenyl (Pz 3) analogues, and 3-(1-ethoxyethyl)-5-ethoxycarbonyl-1H-pyrazole (Pz 4) and its corresponding 1-substituted methyl (Pz 5) and phenyl (Pz 6) analogues) was evaluated by the tail immersion test in adult male albino mice. The animals (N = 11-12 in each group) received vehicle (5% Tween 80, 10 ml/kg, sc) or 1.5 mmol/kg of each of the pyrazolines (Pz 1-Pz 6), sc. Fifteen, thirty and sixty minutes after drug administration, the mice were subjected to the tail immersion test. Thirty minutes after drug administration Pz 2 and Pz 3 increased tail withdrawal latency (vehicle = 3.4 +/- 0.2; Pz 2 = 5.2 +/- 0.4; Pz 3 = 5.9 +/- 0.4 s; mean +/- SEM), whereas the other pyrazolines did not present antinociceptive activity. Dose-effect curves (0.15 to 1.5 mmol/kg) were constructed for the bioactive pyrazolines. Pz 2 (1.5 mmol/kg, sc) impaired motor coordination in the rotarod and increased immobility in the open-field test. Pz 3 did not alter rotarod performance and spontaneous locomotion, but increased immobility in the open field at the dose of 1.5 mmol/kg. The involvement of opioid mechanisms in the pyrazoline-induced antinociception was investigated by pretreating the animals with naloxone (2.75 micro mol/kg, sc). Naloxone prevented Pz 3- but not Pz 2-induced antinociception. Moreover, naloxone pretreatment did not alter Pz 3-induced immobility. We conclude that Pz 3-induced antinociception involves opioid mechanisms but this is not the case for Pz 2.


Assuntos
Analgésicos/farmacologia , Medição da Dor/efeitos dos fármacos , Pirazóis/farmacologia , Animais , Relação Dose-Resposta a Droga , Masculino , Camundongos , Tempo de Reação , Receptores Opioides/efeitos dos fármacos , Restrição Física
10.
J Nat Prod ; 64(7): 997-9, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11473447

RESUMO

Two new cyclopeptides, named discarene C (1) and discarene D (2), have been isolated from the bark of Discaria americana, along with seven known cyclopeptide alkaloids. The structures of the new compounds were determined by spectroscopic methods, mainly NMR. The stereochemistry of the ring amino acid residues have been assigned by gas chromatography employing modified cyclodextrins as chiral stationary phases.


Assuntos
Alcaloides/isolamento & purificação , Peptídeos Cíclicos/isolamento & purificação , Plantas Medicinais/química , Alcaloides/química , Brasil , Cromatografia Gasosa , Cromatografia em Camada Delgada , Leucina/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Peptídeos Cíclicos/química , Fenilalanina/química , Raízes de Plantas/química , Espectrofotometria Infravermelho , Estereoisomerismo
11.
Neurochem Res ; 25(7): 949-55, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10959491

RESUMO

This study examines the effect of new 1,5 benzodiazepines on acetylcholinesterase (AChE) and ATPDase (apyrase) activities from cerebral cortex of adult rats. Simultaneously, the effects of the classical 1,4-benzodiazepine on these enzymes were also studied for comparative purpose. The compounds 2-trichloromethyl-4-phenyl-3H-1,5-benzodiazepin and 2-trichloromethyl-4(p-methyl-phenyl)-3H- 1,5-benzodiazepin significantly inhibited acetylcholinesterase activity (p < 0.01) when tested in the range of 0.18-0.35 mM. The inhibition caused by these two new benzodiazepines was noncompetitive in nature. Similarly, at concentrations ranging from 0.063 to 0.25 mM, the 1,5 benzodiazepines inhibited ATP and ADP hydrolysis by synaptosomes from cerebral cortex (p < 0.01). However, the inhibition of nucleotide hydrolysis was uncompetitive in nature. Our results suggest that, although diazepam and the new benzodiazepines have chemical differences, they both presented an inhibitory effect on acetylcholinesterase and ATPDase activities.


Assuntos
Acetilcolinesterase/metabolismo , Apirase/metabolismo , Benzodiazepinas/farmacologia , Difosfato de Adenosina/antagonistas & inibidores , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/enzimologia , Hidrólise , Cinética , Masculino , Ratos , Ratos Wistar
12.
Biochem Syst Ecol ; 28(9): 907-910, 2000 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-10913853
13.
Recenti Prog Med ; 91(3): 113-5, 2000 Mar.
Artigo em Italiano | MEDLINE | ID: mdl-10763341

RESUMO

In these last years the authors have devoted themselves to chronic alcoholism rehabilitation. They have studied 99 over 65 years old subjects. In these subjects gastrointestinal pathology alcohol correlated incidence has been studied. An abdominal echography and an esophagogastroduodenoscopy have been performed in all these subjects. In some subjects, on the guide line of these tests, the authors have put through more tests: hepatosplenic scintigraphy, hepatic biopsy, laparoscopy, colonoscopy. Statistic elaboration was performed by chi-square test. The conclusions of this study are: 1) the diagnostic importance of association between echography and scintigraphy; 2) the low prevalence of severe hepatic alcohol related lesions in the elderly; 3) the importance of alcohol in hepatocarcinoma etiopathogenesis; 4) the incidence and the importance of phlogistic and ulcerous gastroduodenal lesions in elderly alcoholics.


Assuntos
Alcoolismo/complicações , Carcinoma Hepatocelular/etiologia , Hepatopatias Alcoólicas/epidemiologia , Neoplasias Hepáticas/etiologia , Abdome/diagnóstico por imagem , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Alcoolismo/diagnóstico , Alcoolismo/epidemiologia , Biópsia , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/epidemiologia , Distribuição de Qui-Quadrado , Estudos de Coortes , Endoscopia do Sistema Digestório , Fígado Gorduroso Alcoólico/epidemiologia , Gastroenteropatias/diagnóstico , Gastroenteropatias/epidemiologia , Gastroenteropatias/etiologia , Humanos , Fígado/patologia , Cirrose Hepática Alcoólica/epidemiologia , Hepatopatias Alcoólicas/diagnóstico , Hepatopatias Alcoólicas/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/epidemiologia , Pessoa de Meia-Idade , Cintilografia , Ultrassonografia
14.
Recenti Prog Med ; 88(12): 562-5, 1997 Dec.
Artigo em Italiano | MEDLINE | ID: mdl-9522596

RESUMO

Patients with alcohol addiction are analyzed after one year from the beginning of therapy. Treatment is carried out by an Anti-addiction Service working in territory, an Hospital medical ward, anti-alcoholic clubs and Hospital voluntary groups. The method is described at first, then the answers of investigated patients, the abstinence period, the attendance to help groups, the use of drugs (disulfiram) and the emerged problems are considered and analyzed. More than one year later, patients with alcohol addiction who have followed this method are still in abstinence and have changed their habit from alcoholic to unalcoholic one, as just they have done for the behaviour and the relationship.


Assuntos
Alcoolismo/terapia , Adulto , Idoso , Dissuasores de Álcool/uso terapêutico , Alcoolismo/tratamento farmacológico , Alcoolismo/reabilitação , Dissulfiram/análogos & derivados , Dissulfiram/uso terapêutico , Educação , Estudos de Avaliação como Assunto , Família , Seguimentos , Humanos , Pessoa de Meia-Idade , Grupos de Autoajuda , Inquéritos e Questionários , Fatores de Tempo
15.
Biochemistry ; 33(9): 2430-40, 1994 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-8117703

RESUMO

Natural-abundance 13C-NMR spectra have been obtained for four self-complementary DNA oligonucleotides: [d(TAGCGCTA)]2, [d(GGTATACC)]2, [d(CG)3]2, and [d(TCGCG)]2; this paper focuses on the deoxyribose resonances. Assignments were made by a combination of the two-dimensional proton-detected heteronuclear correlation experiment and comparison of 1D spectra, accounting for 31P coupling, base composition, and similarities in chemical shift versus temperature profiles (delta vs T). Large shielding and deshielding of the sugar resonances (between 2.0 and -1.9 ppm) are observed upon thermal dissociation of the duplex. The shapes of the delta vs T profiles correlate strongly with the purine/pyrimidine nature of the base attached at C1' in these duplexes that have a substantial fraction of residues within alternating purine-pyrimidine sequences. The correlation is primarily associated with changes in the equilibrium distribution of furanose pseudorotational states that may arise in part from the relief of interstrand purine-purine steric clashes.


Assuntos
DNA/química , Desoxirribose/química , Conformação de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Espectroscopia de Ressonância Magnética
16.
Biochemistry ; 33(9): 2441-50, 1994 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-8117704

RESUMO

Natural-abundance 13C-NMR spectra of [d(TCGCG)] (1), [d(CGCGCG)]2 (2), and [d(GGTATACC)]2 (3) were measured at 90.6 MHz to obtain 13C-1H NOEs and T1 relaxation times; relaxation data were also measured at 125.7 MHz for 1 and 2 and at 62.9 MHz for 1. Analysis of the relaxation data was performed in the context of the "model-free" approach of Lipari and Szabo [Lipari, G., & Szabo, A. (1982) J. Am. Chem. Soc. 104, 4546-4559], leading to the following conclusions: (i) Optimized values for the overall correlation times of 0.9 ns for 1 and 1.4 ns for 2 are close to those predicted by light-scattering results on similar molecules [Eimer et al. (1990) Biochemistry 29, 799-811]. (ii) For the nonterminal residues, the "order parameter", S2, is around 0.8 for the protonated base carbons and 0.6 for the sugar carbons, indicating less spatial restriction on the sugar carbons (in the model-free approach, the order parameter is 1 for a rigid body and 0 for a system with completely unrestricted internal motion). (iii) The order parameters for the terminal residues vary over a wide range with the smallest values around 0.2-0.3 for the HO-13C5' and the 13C3'-OH; rational trends are seen in the variation of S2 with chain position in the terminal residues. (iv) The analysis shows that the order parameters are accurate within 15%. (v) The "effective internal correlation time", tau e, is very short for the sugar carbons (30-300 ps) and less well-defined, but probably also short, for the bases. (vi) The analysis indicates that most of the relaxation in DNA is accounted for by S2 and the tau e is so short that a good approximation to any relaxation property, P (e.g., T1, T2, 13C-1H NOE, 1H-1H cross-relaxation rate), is P = S2Prigid, where Prigid is the value for the property in a system without internal motion (the analysis assumes the same isotropic overall motion for both the rigid and flexible bodies).


Assuntos
DNA/química , Conformação de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Sequência de Bases , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Movimento (Física)
17.
Acta Haematol ; 81(1): 28-33, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2494831

RESUMO

Sixteen patients with chronic idiopathic thrombocytopenic purpura underwent splenectomy after failure of steroid therapy. The average time of follow-up was 69 months. Immediately after splenectomy, complete response (platelets above 150 x 10(9)/l) was obtained by 68% of patients while 25% had partial response (platelets from 50 to 150 x 10(9)/l) and only in 1 patient splenectomy failed. During the long-term follow-up, 2 patients relapsed 9 and 20 years, respectively, after splenectomy (20% of non-responders). Partial recurrence of thrombocytopenia (partial response) was observed in 33% of the patients. The persistent complete response rate was then 47%. The young patient age appears to be the only positive predictive factor both for short-term and long-term response to splenectomy. The platelet recovery rate and postsplenectomy thrombocytosis are also early features of lasting response. Positive serum and platelet-associated immunoglobulins became negative after splenectomy, but there is no correlation with clinical response.


Assuntos
Púrpura Trombocitopênica/cirurgia , Esplenectomia , Adulto , Plaquetas/imunologia , Doença Crônica , Feminino , Humanos , Imunoglobulina G/análise , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Prednisona/uso terapêutico , Prognóstico , Púrpura Trombocitopênica/sangue , Púrpura Trombocitopênica/tratamento farmacológico
18.
Biochemistry ; 27(20): 7902-9, 1988 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-3207718

RESUMO

Natural abundance 13C NMR spectra of three DNA oligomers have been obtained. Most of the base resonances are well resolved from one another. A combination of two independent methods was used in making assignments: a one-dimensional spectral comparison method and a two-dimensional proton-detected 1H-13C correlated experiment for the protonated carbons. There are large shielding changes (between 1.62 and -1.40 ppm) upon thermal dissociation of the duplex. The shapes of the chemical shift vs temperature curves are largely independent of sequence. The base carbon resonance frequencies are sensitive to hydrogen bonding, base stacking, sugar conformation, and changes in the glycosyl torsion angle.


Assuntos
DNA , Oligodesoxirribonucleotídeos , Composição de Bases , Sequência de Bases , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Conformação de Ácido Nucleico , Polidesoxirribonucleotídeos , Termodinâmica
19.
Nucleic Acids Res ; 16(5): 2323-32, 1988 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-3357779

RESUMO

13C-nmr chemical shifts of the nucleotides in DNA are sensitive to hydrogen bonding, especially for three of the carbons immediately bonded to exocyclic oxygen or nitrogen atoms acting as H-bond acceptors or donors. GuoC2, GuoC6 and ThdC4 are strongly deshielded (about 1 ppm) upon Watson-Crick pairing in oligodeoxynucleotide duplexes, regardless of the base sequence. Deshielding at these sites may be useful to distinguish bases involved in Watson-Crick pairs from unpaired bases.


Assuntos
Físico-Química , DNA , Ligação de Hidrogênio , Fenômenos Químicos , Temperatura Alta , Espectroscopia de Ressonância Magnética
20.
J Biomol Struct Dyn ; 1(6): 1373-86, 1984 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6400826

RESUMO

Natural abundance 13C NMR spectra of duplexed (dC-dG)3 and (dC-dG)4 exhibit resolved resonances for most of the carbons at 0.1M NaCl in aqueous solution. Large transitions in chemical shift for many of the hexamer carbons (up to 1.8 ppm) are observed in variable temperature measurements. Determination of spin-lattice relaxation times and nuclear Overhauser enhancements in 0.1M NaCl indicate that the duplexes tumble almost isotropically, with overall correlation times near 5 nsec; the sugar carbons experience more rapid local motions than do the base carbons. The relaxation data are also consistent with the most rapid local motions occurring at the chain-terminal residues, especially in the Cyd(1) sugar. 4M NaCl causes changes in the 13C chemical shifts of most of the guanine base carbons, and rearrangements in the deoxyribose carbon shifts; this is consistent with changes predicted by a salt-induced B to Z transition, viz. conversion of the guanylates from the anti to syn range about the glycosyl bond, and from the S to N pseudorotational state of the deoxyribose ring.


Assuntos
DNA , Conformação de Ácido Nucleico , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Oligodesoxirribonucleotídeos , Soluções , Temperatura
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