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1.
Eur J Intern Med ; 77: 79-85, 2020 07.
Article in English | MEDLINE | ID: mdl-32151490

ABSTRACT

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.


Subject(s)
Cardiovascular Diseases , Neoplasms , Ankle Brachial Index , Heart Disease Risk Factors , Humans , Italy/epidemiology , Predictive Value of Tests , Prognosis , Risk Factors
2.
Braz J Med Biol Res ; 43(12): 1193-202, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21140097

ABSTRACT

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.


Subject(s)
Antioxidants/pharmacology , Antipyretics/pharmacology , Oxidative Stress/drug effects , Pyrazoles/pharmacology , Animals , Antipyretics/chemistry , Cyclooxygenase 1/pharmacology , Cyclooxygenase 2/pharmacology , Interleukin-1beta/drug effects , Interleukin-1beta/metabolism , Male , Pyrazoles/chemistry , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/drug effects , Tumor Necrosis Factor-alpha/metabolism
3.
Braz. j. med. biol. res ; 43(12): 1193-1202, Dec. 2010. ilus
Article in English | LILACS | ID: lil-569003

ABSTRACT

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.


Subject(s)
Animals , Male , Rats , Antioxidants/pharmacology , Antipyretics/pharmacology , Oxidative Stress/drug effects , Pyrazoles/pharmacology , Antipyretics/chemistry , Cyclooxygenase 1/pharmacology , /pharmacology , Interleukin-1beta/drug effects , Interleukin-1beta/metabolism , Pyrazoles/chemistry , Rats, Wistar , Tumor Necrosis Factor-alpha/drug effects , Tumor Necrosis Factor-alpha/metabolism
4.
Braz J Med Biol Res ; 39(6): 795-9, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16751986

ABSTRACT

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.


Subject(s)
Analgesics/pharmacology , Pain Measurement/drug effects , Pyrazoles/pharmacology , Thiazoles/pharmacology , Acetic Acid , Animals , Dose-Response Relationship, Drug , Male , Mice , Motor Activity/drug effects , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Pyrazoles/chemistry , Reaction Time , Thiazoles/chemistry
5.
Braz. j. med. biol. res ; 39(6): 795-799, June 2006. graf
Article in English | LILACS | ID: lil-428270

ABSTRACT

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.


Subject(s)
Animals , Male , Mice , Analgesics/pharmacology , Pain Measurement/drug effects , Pyrazoles/pharmacology , Thiazoles/pharmacology , Acetic Acid , Dose-Response Relationship, Drug , Motor Activity/drug effects , Naloxone/pharmacology , Narcotic Antagonists/pharmacology , Pyrazoles/chemistry , Reaction Time , Thiazoles/chemistry
7.
J Inorg Biochem ; 99(9): 1853-7, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16098596

ABSTRACT

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.


Subject(s)
Aluminum/toxicity , Chelating Agents/chemistry , Models, Chemical , Pyrimidines/chemistry , Aluminum/chemistry , Animals , Male , Mice
8.
Braz. j. med. biol. res ; 37(10): 1531-1540, Oct. 2004. tab, graf
Article in English | LILACS | ID: lil-383035

ABSTRACT

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.


Subject(s)
Animals , Male , Mice , Analgesics , Pain Measurement , Pyrazoles , Analysis of Variance , Dose-Response Relationship, Drug , Reaction Time , Receptors, Opioid , Restraint, Physical
9.
Braz J Med Biol Res ; 37(10): 1531-40, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15448875

ABSTRACT

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.


Subject(s)
Analgesics/pharmacology , Pain Measurement/drug effects , Pyrazoles/pharmacology , Animals , Dose-Response Relationship, Drug , Male , Mice , Reaction Time , Receptors, Opioid/drug effects , Restraint, Physical
10.
J Nat Prod ; 64(7): 997-9, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11473447

ABSTRACT

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.


Subject(s)
Alkaloids/isolation & purification , Peptides, Cyclic/isolation & purification , Plants, Medicinal/chemistry , Alkaloids/chemistry , Brazil , Chromatography, Gas , Chromatography, Thin Layer , Leucine/chemistry , Magnetic Resonance Spectroscopy , Molecular Structure , Peptides, Cyclic/chemistry , Phenylalanine/chemistry , Plant Roots/chemistry , Spectrophotometry, Infrared , Stereoisomerism
11.
Neurochem Res ; 25(7): 949-55, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10959491

ABSTRACT

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.


Subject(s)
Acetylcholinesterase/metabolism , Apyrase/metabolism , Benzodiazepines/pharmacology , Adenosine Diphosphate/antagonists & inhibitors , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/antagonists & inhibitors , Adenosine Triphosphate/metabolism , Animals , Cerebral Cortex/drug effects , Cerebral Cortex/enzymology , Hydrolysis , Kinetics , Male , Rats , Rats, Wistar
12.
Biochem Syst Ecol ; 28(9): 907-910, 2000 Nov 01.
Article in English | MEDLINE | ID: mdl-10913853
13.
Recenti Prog Med ; 91(3): 113-5, 2000 Mar.
Article in Italian | MEDLINE | ID: mdl-10763341

ABSTRACT

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.


Subject(s)
Alcoholism/complications , Carcinoma, Hepatocellular/etiology , Liver Diseases, Alcoholic/epidemiology , Liver Neoplasms/etiology , Abdomen/diagnostic imaging , Age Factors , Aged , Aged, 80 and over , Alcoholism/diagnosis , Alcoholism/epidemiology , Biopsy , Carcinoma, Hepatocellular/diagnosis , Carcinoma, Hepatocellular/diagnostic imaging , Carcinoma, Hepatocellular/epidemiology , Chi-Square Distribution , Cohort Studies , Endoscopy, Digestive System , Fatty Liver, Alcoholic/epidemiology , Gastrointestinal Diseases/diagnosis , Gastrointestinal Diseases/epidemiology , Gastrointestinal Diseases/etiology , Humans , Liver/pathology , Liver Cirrhosis, Alcoholic/epidemiology , Liver Diseases, Alcoholic/diagnosis , Liver Diseases, Alcoholic/diagnostic imaging , Liver Neoplasms/diagnosis , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/epidemiology , Middle Aged , Radionuclide Imaging , Ultrasonography
14.
Recenti Prog Med ; 88(12): 562-5, 1997 Dec.
Article in Italian | MEDLINE | ID: mdl-9522596

ABSTRACT

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.


Subject(s)
Alcoholism/therapy , Adult , Aged , Alcohol Deterrents/therapeutic use , Alcoholism/drug therapy , Alcoholism/rehabilitation , Disulfiram/analogs & derivatives , Disulfiram/therapeutic use , Education , Evaluation Studies as Topic , Family , Follow-Up Studies , Humans , Middle Aged , Self-Help Groups , Surveys and Questionnaires , Time Factors
15.
Biochemistry ; 33(9): 2430-40, 1994 Mar 08.
Article in English | MEDLINE | ID: mdl-8117703

ABSTRACT

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.


Subject(s)
DNA/chemistry , Deoxyribose/chemistry , Nucleic Acid Conformation , Oligodeoxyribonucleotides/chemistry , Magnetic Resonance Spectroscopy
16.
Biochemistry ; 33(9): 2441-50, 1994 Mar 08.
Article in English | MEDLINE | ID: mdl-8117704

ABSTRACT

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).


Subject(s)
DNA/chemistry , Nucleic Acid Conformation , Oligodeoxyribonucleotides/chemistry , Base Sequence , Magnetic Resonance Spectroscopy , Molecular Sequence Data , Motion
17.
Acta Haematol ; 81(1): 28-33, 1989.
Article in English | MEDLINE | ID: mdl-2494831

ABSTRACT

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.


Subject(s)
Purpura, Thrombocytopenic/surgery , Splenectomy , Adult , Blood Platelets/immunology , Chronic Disease , Female , Humans , Immunoglobulin G/analysis , Male , Middle Aged , Platelet Count , Prednisone/therapeutic use , Prognosis , Purpura, Thrombocytopenic/blood , Purpura, Thrombocytopenic/drug therapy
18.
Biochemistry ; 27(20): 7902-9, 1988 Oct 04.
Article in English | MEDLINE | ID: mdl-3207718

ABSTRACT

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.


Subject(s)
DNA , Oligodeoxyribonucleotides , Base Composition , Base Sequence , Hydrogen Bonding , Magnetic Resonance Spectroscopy , Nucleic Acid Conformation , Polydeoxyribonucleotides , Thermodynamics
19.
Nucleic Acids Res ; 16(5): 2323-32, 1988 Mar 25.
Article in English | MEDLINE | ID: mdl-3357779

ABSTRACT

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.


Subject(s)
Chemistry, Physical , DNA , Hydrogen Bonding , Chemical Phenomena , Hot Temperature , Magnetic Resonance Spectroscopy
20.
J Biomol Struct Dyn ; 1(6): 1373-86, 1984 Jun.
Article in English | MEDLINE | ID: mdl-6400826

ABSTRACT

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.


Subject(s)
DNA , Nucleic Acid Conformation , Magnetic Resonance Spectroscopy , Molecular Structure , Oligodeoxyribonucleotides , Solutions , Temperature
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