Phaeophytins from Thyrsacanthus ramosissimus Moric. with inhibitory activity on human dna topoisomerase II-α

Our study reports the extraction and isolation of a new phaeophytin derivative 15¹-hydroxy-(15¹-S)-porphyrinolactone, designated anamariaine (1) herein, isolated from the chloroform fraction of aerial parts of Thyrsacanthus ramosissimus Moric. along with the known 15¹-ethoxy-(15¹-S)-porphyrinolactone (2). These compounds were identified by usual spectroscopic methods. Both compounds were subjected to in vitro (inhibitory activity) tests by means of supercoiled DNA relaxation techniques and were shown to display inhibitory activity against human DNA topoisomerase II-α at 50 µM. Interconversion of these two pigments under the mild conditions of the isolation techniques should be highly unlikely but cannot be entirely ruled out.

Neolignans from Licaria chrysophylla and Licaria aurea with DNA topoisomerase II-α inhibitory activity

Seven natural neolignans isolated from Licaria chrysophylla and Licaria aurea along with five semisynthetic derivatives were tested for their inhibitory action on DNA-topoisomerase by relaxation assays on pBR322 plasmid DNA. All compounds tested showed strong inhibition at a concentration of 100 µM, while none showed activity between 5 and 70 µM. These results indicate that no obvious correlation can be derived between the structure of these compounds and their inhibitory effect on the DNA relaxation activity of topoisomerase II. This is the first report on DNA topoisomerase II inhibitors from Licaria chrysophylla and Licaria aurea leading to the identification of lignoids as topoisomerase II-α inhibitors.

USO DA RMN DE BAIXA RESOLUÇÃO NA AVALIAÇÃO DA DINÂMICA MOLECULAR DO Origanum vulgare

In this work, proton NMR relaxometry was used to measure the behavior of spin-lattice relaxation time with T1H as the time constant, and also of spin-spin relaxation time with the time constant T2H. These relaxometry parameters were determined to better understand the changes in the main structures present in commercial and in nature forms of origanum. The T1H relaxation data showed that the structures which had higher molecular mass were more sensitive to degradation with increased temperature treatment. According to the values of the T2H parameter, up to 150 degrees no significant change in the mobility and organization of water was observed. These data infer that the ideal cooking temperature and tea preparation mode for this herb should be around 100 degrees for the sample not to lose its characteristics. Also, it is not advisable to cook this herb at higher than 150 degrees but better to consume it at room temperature, especially give commercial herb has already been dehydrated.

Dielectric spectroscopy and thermally stimulated discharge current in PEEK film

The complex permittivity of films of polyether ether ketone (PEEK) has been investigated over a wide range of frequency. There is no relaxation peak in the range of 1Hz to 10(5) Hz but in the low-frequency side (10-4 Hz) there is an evidence of a peak that also can be observed by thermally stimulated discharge current measurements. That peak is related with the glass transition temperature (Tg) of the polymer. The activation energy of the relaxation was found to be 0.44 eV, similar to that of several synthetic polymers. Space charges are important in the conduction mechanism as shown by discharging transient.

Anatomical and functional characteristics of the pelvic floor in nulliparous women submitted to three-dimensional endovaginal ultrasonography: case control study and evaluation of interobserver agreement

PURPOSE: To determine anatomical and functional pelvic floor measurements performed with three-dimensional (3-D) endovaginal ultrasonography in asymptomatic nulliparous women without dysfunctions detected in previous dynamic 3-D anorectal ultrasonography (echo defecography) and to demonstrate the interobserver reliability of these measurements. METHODS: Asymptomatic nulliparous volunteers were submitted to echo defecography to identify dynamic dysfunctions, including anatomical (rectocele, intussusceptions, entero/sigmoidocele and perineal descent) and functional changes (non-relaxation or paradoxical contraction of the puborectalis muscle) in the posterior compartment and assessed with regard to the biometric index of levator hiatus, pubovisceral muscle thickness, urethral length, anorectal angle, anorectal junction position and bladder neck position with the 3-D endovaginal ultrasonography. All measurements were compared at rest and during the Valsalva maneuver, and perineal and bladder neck descent was determined. The level of interobserver agreement was evaluated for all measurements. RESULTS: A total of 34 volunteers were assessed by echo defecography and by 3-D endovaginal ultrasonography. Out of these, 20 subjects met the inclusion criteria. The 14 excluded subjects were found to have posterior dynamic dysfunctions. During the Valsalva maneuver, the hiatal area was significantly larger, the urethra was significantly shorter and the anorectal angle was greater. Measurements at rest and during the Valsalva maneuver differed significantly with regard to anorectal junction and bladder neck position. The mean values for normal perineal descent and bladder neck descent were 0.6 cm and 0.5 cm above the symphysis pubis, respectively. The intraclass correlation coefficient ranged from 0.62-0.93. CONCLUSIONS: Functional biometric indexes, normal perineal descent and bladder neck descent values were determined for young asymptomatic nulliparous women with the 3-D endovaginal ultrasonography. The method was found to be reliable to measure pelvic floor structures at rest and during Valsalva, and might therefore be suitable for identifying dysfunctions in symptomatic patients.

Evaluation of left ventricular diastolic echocardiographic parameters in healthy dogs by pulsed-wave Doppler

Left ventricular diastolic dysfunction plays an important role on heart failure progression. In order to obtain additional reference values of left ventricular diastolic parameters and investigate influence of common variables, peak E wave (peak E), peak A wave (peak A), E/A ratio (E/A), E wave deceleration time (EDT) and isovolumic relaxation time (IRVT) were studied in 40 clinically healthy dogs, by pulsed wave Doppler. The following values were obtained: peak E = 0.747 ± 0.117 m/s, peak A = 0.487 ± 0.062 m/s, E/A = 1.533 ± 0.198, EDT = 88.7 ± 9.2 ms and IRVT = 0.080 ± 0.009 s. Some parameters were influenced by heart rate (peak E, peak A and IRVT), by age (peak A and E/A) and by body weight (TRIV). Gender influence was absent. Values obtained can be used as reference for canine specimens but its interpretation should consider on the influence of related variables.

Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig

We investigated the effects of piperitenone oxide (PO), a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 µg/ml) relaxed basal tonus without significantly altering the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethylammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 µg/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (>30 µg/ml) blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect

Gender effects on esophageal motility

It has been suggested that there are no gender effects on esophageal motility. However, in previous studies the subjects did not perform multiple swallows and the quantitative features of esophageal contractions were not evaluated. In order to investigate the gender effects on esophageal motility we studied 40 healthy normal volunteers, 20 men aged 37 ± 15 years (mean ± SD), and 20 women aged 38 ± 14 years. We used the manometric method with an eight-lumen polyvinyl catheter and continuous perfusion. The upper and lower esophageal sphincter pressures were measured by the rapid pull-through method. With the catheter positioned with one lumen opening in the lower esophageal sphincter, and the others at 5, 10 and 15 cm above the sphincter, ten swallows of a 5-ml water bolus alternated with ten dry swallows were performed. Statistical analysis was done by the Student t-test and Mann-Whitney test. Gender differences (P<0.05) were observed for wet swallows in the duration of contractions 5 cm above the lower esophageal sphincter (men: 3.7 ± 0.2 s, women: 4.5 ± 0.3 s, mean ± SEM), and in the velocity of contractions from 15 to 10 cm above the lower esophageal sphincter (men: 4.7 ± 0.3 cm/s, women: 3.5 ± 0.2 cm/s). There was no difference (P>0.05) in sphincter pressure, duration and percentage of complete lower esophageal sphincter relaxation, amplitude of contractions, or in the number of failed, multipeaked and synchronous contractions. We conclude that gender may cause some differences in esophageal motility which, though of no clinical significance, should be taken into consideration when interpreting esophageal motility tests.

The effect of L-arginine on guinea-pig and rabbit airway smooth muscle function in vitro

We have investigated the effects of L-arginine, D-arginine and L-lysine on airway smooth muscle responsiveness to spasmogens in vitro. Both L-arginine and D-arginine (100 mM) significantly reduced the contractile potency and maximal contractile response to histamine but not to methacholine or potassium chloride in guinea-pig epithelium-denuded isolated trachea. Similarly, the contractile response to histamine was significantly reduced by L-arginine (100 mM) in rabbit epithelium-denuded isolated bronchus. The amino acid L-lysine (100 mM) failed to significantly alter the contractile potency of histamine in guinea-pig isolated trachea (P>0.05). In guinea-pig isolated trachea precontracted with histamine, both L-arginine and D-arginine produced a concentration-dependent relaxation which was not significantly altered by epithelium removal or by the presence of the nitric oxide synthase inhibitor, NG-nitro L-arginine methyl ester (L-NAME; 50 µM). Thus, at very high concentrations, arginine exhibit a non-competitive antagonism of histamine-induced contraction of isolated airway preparations that was independent of the generation of nitric oxide and was not dependent on charge. These observations confirm previous studies of cutaneous permeability responses and of contractile responses of guinea-pig isolated ileal smooth muscle. Taken together, the data suggest that high concentrations of arginine can exert an anti-histamine effect.

Endothelium-dependent vasodilation in response to Pseudomonas aeruginosa lipopolysaccharide: an in vitro study on canine arteries

Early systemic arterial hypotension is a common clinical feature of Pseudomonas septicemia. To determine if Pseudomonas aeruginosa endotoxin induces the release of endothelium-derived nitric oxide (EDNO), an endogenous nitrovasodilator, segments of canine femoral, renal, hepatic, superior mesenteric, and left circumflex coronary arteries were suspended in organ chambers (physiological salt solution, 95% O2/5% CO2, pH 7.4, 37oC) to measure isometric force. In arterial segments contracted with 2 µM prostaglandin F2a, Pseudomonas endotoxin (lipopolysaccharide (LPS) serotype 10(Habs) from Pseudomonas aeruginosa (0.05 to 0.50 mg/ml)) induced concentration-dependent relaxation of segments with endothelium (P<0.05) but no significant change in tension of arteries without endothelium. Endothelium-dependent relaxation in response to Pseudomonas LPS occurred in the presence of 1 µM indomethacin, but could be blocked in the coronary artery with 10 µM NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthesis from L-arginine. The inhibitory effect of L-NMMA on LPS-mediated vasorelaxation of the coronary artery could be reversed by exogenous 100 µM L-arginine but not by 100 µM D-arginine. These experiments indicate that Pseudomonas endotoxin induces synthesis of nitric oxide from L-arginine by the vascular endothelium. LPS-mediated production of EDNO by the endothelium, possibly through the action of constitutive nitric oxide synthase (NOSc), may decrease systemic vascular resistance and may be the mechanism of early hypotension characteristic of Pseudomonas septicemia.

Neuronal and endothelial nitric oxide synthase gene knockout mice

Targeted disruption of the neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) genes has led to knockout mice that lack these isoforms. These animal models have been useful to study the roles of nitric oxide (NO) in physiologic processes. nNOS knockout mice have enlarged stomachs and defects in the inhibitory junction potential involved in gastrointestinal motility. eNOS knockout mice are hypertensive and lack endothelium-derived relaxing factor activity. When these animals are subjected to models of focal ischemia, the nNOS mutant mice develop smaller infarcts, consistent with a role for nNOS in neurotoxicity following cerebral ischemia. In contrast, eNOS mutant mice develop larger infarcts, and show a more pronounced hemodynamic effect of vascular occlusion. The knockout mice also show that nNOS and eNOS isoforms differentially modulate the release of neurotransmitters in various regions of the brain. eNOS knockout mice respond to vessel injury with greater neointimal proliferation, confirming that reduced NO levels seen in endothelial dysfunction change the vessel response to injury. Furthermore, eNOS mutant mice still show a protective effect of female gender, indicating that the mechanism of this protection cannot be limited to upregulation of eNOS expression. The eNOS mutant mice also prove that eNOS modulates the cardiac contractile response to ß-adrenergic agonists and baseline diastolic relaxation. Atrial natriuretic peptide, upregulated in the hearts of eNOS mutant mice, normalizes cGMP levels and restores normal diastolic relaxation.

Biophysical characteristics of gap junctions in vascular wall cells: implications for vascular biology and disease

The role gap junction channels play in the normal and abnormal functioning of the vascular wall is the subject of much research. The biophysical properties of gap junctions are an essential component in understanding how gap junctions function to allow coordinated relaxation and contraction of vascular smooth muscle. This study reviews the properties thus far elucidated and relates those properties to tissue function. We ask how biophysical and structural properties such as gating, permselectivity, subconductive states and channel type (heteromeric vs homotypic vs heterotypic) might affect vascular smooth muscle tone.

Ambulatory blood pressure and Doppler echocardiographic indexes of borderline hypertensive men presenting an exaggerated blood pressure response during dynamic exercise

Borderline hypertension (BH) has been associated with an exaggerated blood pressure (BP) response during laboratory stressors. However, the incidence of target organ damage in this condition and its relation to BP hyperreactivity is an unsettled issue. Thus, we assessed the Doppler echocardiographic profile of a group of BH men (N = 36) according to office BP measurements with exaggerated BP in the cycloergometric test. A group of normotensive men (NT, N = 36) with a normal BP response during the cycloergometric test was used as control. To assess vascular function and reactivity, all subjects were submitted to the cold pressor test. Before Doppler echocardiography, the BP profile of all subjects was evaluated by 24-h ambulatory BP monitoring. All subjects from the NT group presented normal monitored levels of BP. In contrast, 19 subjects from the original BH group presented normal monitored BP levels and 17 presented elevated monitored BP levels. In the NT group all Doppler echocardiographic indexes were normal. All subjects from the original BH group presented normal left ventricular mass and geometrical pattern. However, in the subjects with elevated monitored BP levels, fractional shortening was greater, isovolumetric relaxation time longer, and early to late flow velocity ratio was reduced in relation to subjects from the original BH group with normal monitored BP levels (P<0.05). These subjects also presented an exaggerated BP response during the cold pressor test. These results support the notion of an integrated pattern of cardiac and vascular adaptation during the development of hypertension.

Esophageal striated muscle contractions in patients with Chagas' disease and idiopathic achalasia

Chagas' disease causes degeneration and reduction of the number of intrinsic neurons of the esophageal myenteric plexus, with consequent absent or partial lower esophageal sphincter relaxation and loss of peristalsis in the esophageal body. The impairment of esophageal motility is seen mainly in the distal smooth muscle region. There is no study about esophageal striated muscle contractions in the disease. In 81 patients with heartburn (44 with esophagitis) taken as controls, 51 patients with Chagas' disease (21 with esophageal dilatation) and 18 patients with idiopathic achalasia (11 with esophageal dilatation) we studied the amplitude, duration and area under the curve of esophageal proximal contractions. Using the manometric method and a continuous perfusion system we measured the esophageal striated muscle contractions 2 to 3 cm below the upper esophageal sphincter after swallows of a 5-ml bolus of water. There was no significant difference in striated muscle contractions between patients with heartburn and esophagitis and patients with heartburn without esophagitis. There was also no significant difference between patients with heartburn younger or older than 50 years or between men and women or in esophageal striated muscle contractions between patients with heartburn and Chagas' disease. The esophageal proximal amplitude of contractions was lower in patients with idiopathic achalasia than in patients with heartburn. In patients with Chagas' disease there was no significant difference between patients with esophageal dilatation and patients with normal esophageal diameter. Esophageal striated muscle contractions in patients with Chagas' disease have the same amplitude and duration as seen in patients with heartburn. Patients with idiopathic achalasia have a lower amplitude of contraction than patients with heartburn.

DNA topoisomerase inhibitors: biflavonoids from Ouratea species

Topoisomerase inhibitors are agents with anticancer activity. 7"-O-Methyl-agathisflavone (I) and amentoflavone (II) are biflavonoids and were isolated from the Brazilian plants Ouratea hexasperma and O. semiserrata, respectively. These biflavonoids and the acetyl derivative of II (IIa) are inhibitors of human DNA topoisomerases I at 200 µM, as demonstrated by the relaxation assay of supercoiled DNA, and only agathisflavone (I) at 200 µM also inhibited DNA topoisomerases II-alpha, as observed by decatenation and relaxation assays. The biflavonoids showed concentration-dependent growth inhibitory activities on Ehrlich carcinoma cells in 45-h culture, assayed by a tetrazolium method, with IC50 = 24 ± 1.4 µM for I, 26 ± 1.1 µM for II and 10 ± 0.7 µM for IIa. These biflavonoids were assayed against human K562 leukemia cells in 45-h culture, but only I showed 42% growth inhibitory activity at 90 µM. Our results suggest that biflavonoids are targets for DNA topoisomerases and their cytotoxicity is dependent on tumor cell type.