Pixantrone anticancer drug as a DNA ligand: Depicting the mechanism of action at single molecule level.

In this work we use single molecule force spectroscopy performed with optical tweezers in order to characterize the complexes formed between the anticancer drug Pixantrone (PIX) and the DNA molecule, at two very different ionic strengths. Firstly, the changes of the mechanical properties of the DNA-PIX complexes were studied as a function of the drug concentration in the sample. Then, a quenched-disorder statistical model of ligand binding was used in order to determine the physicochemical (binding) parameters of the DNA-PIX interaction. In particular, we have found that the PIX molecular mechanism of action involves intercalation into the double helix, followed by a significant compaction of the DNA molecule due to partial neutralization of the phosphate backbone. Finally, this scenario of interaction was quantitatively compared to that found for the related drug Mitoxantrone (MTX), which binds to DNA with a considerably higher equilibrium binding constant and promotes a much stronger DNA compaction. The comparison performed between the two drugs can bring clues to the development of new (and more efficient) related compounds.

Eag1, Eag2, and SK3 potassium channel expression in the rat hippocampus after global transient brain ischemia.

Transient global brain ischemia causes delayed neuronal death in the hippocampus that has been associated with impairments in hippocampus-dependent brain function, such as mood, learning, and memory. We investigated the expression of voltage-dependent Kcnh1 and Kcnh5, ether à go-go-related Eag1 and Eag2 (K(V) 10.1 and K(V) 10.2), and small-conductance calcium-activated SK3 (K(Ca) 2.3, Kcnn3) K(+) channels in the hippocampus in rats after transient global brain ischemia. We tested whether the expression of these channels is associated with behavioral changes by evaluating the animals in the elevated plus maze and step-down inhibitory avoidance task. Seven or tweny-eight days after transient global brain ischemia, one group of rats had the hippocampus bilaterally dissected, and mRNA levels were determined. Seven days after transient global brain ischemia, the rats exhibited a decrease in anxiety-like behavior and memory impairments. An increase in anxiety levels was detected 28 days after ischemia. Eag2 mRNA downregulation was observed in the hippocampus 7 days after transient global brain ischemia, whereas Eag1 and SK3 mRNA expression remained unaltered. This is the first experimental evidence that transient global brain ischemia temporarily alters Eag2. The number of intact-appearing pyramidal neurons was substantially decreased in CA1 and statistically measurable in CA2, CA3, and CA4 hippocampal subfields compared with sham control animals 7 or 28 days after ischemia. mRNA expression in the rat hippocampus. The present results provide further information for the characterization of the physiological role of Eag2 channels in the central nervous system.

Connecting complex networks to nonadditive entropies.

Boltzmann-Gibbs statistical mechanics applies satisfactorily to a plethora of systems. It fails however for complex systems generically involving nonlocal space-time entanglement. Its generalization based on nonadditive q-entropies adequately handles a wide class of such systems. We show here that scale-invariant networks belong to this class. We numerically study a d-dimensional geographically located network with weighted links and exhibit its 'energy' distribution per site at its quasi-stationary state. Our results strongly suggest a correspondence between the random geometric problem and a class of thermal problems within the generalised thermostatistics. The Boltzmann-Gibbs exponential factor is generically substituted by its q-generalisation, and is recovered in the [Formula: see text] limit when the nonlocal effects fade away. The present connection should cross-fertilise experiments in both research areas.

Vascular endothelial growth factor concentrations in the serum and peritoneal fluid of women with endometriosis.

OBJECTIVES: To investigate whether there is an association between vascular endothelial growth factor (VEGF) levels in serum and peritoneal fluid, and the presence of pelvic endometriosis and its clinical symptoms. METHODS: Blood and peritoneal fluid sample levels of VEGF were measured in 46 women undergoing laparoscopy: 32 with suspected endometriosis and 14 with confirmed endometriosis. Data were analyzed according to phase of the menstrual cycle, symptoms, disease stage, and disease site. RESULTS: There were no significant associations between serum and peritoneal fluid levels of VEGF and the presence of endometriosis, even when controlling for the menstrual phase. However, among the women with confirmed endometriosis, there was a significant increase (P=0.002) in the mean peritoneal VEGF level in those in the late secretory phase compared with those in the proliferative and early secretory phases. CONCLUSIONS: Measuring VEGF levels in symptomatic patients is not helpful to differentiate those with endometriosis from those with a different condition. However, in the late secretory and menstrual phases, mean VEGF levels were higher in women with confirmed endometriosis than in those suspected of having the disease.

Serotypes of carriage and invasive isolates of Streptococcus pneumoniae in Brazilian children in the era of pneumococcal vaccines.

Nasopharyngeal carriage of Streptococcus pneumoniae is a key factor in the development of invasive disease and the spread of resistant strains within the community. A single nasopharyngeal swab was obtained from 648 unvaccinated children aged <5 years, either healthy or with acute respiratory tract infection or meningitis, during the winters of 2000 and 2001. The overall pneumococcal carriage rate was 35.8% (95% CI 32.1-39.6). The pneumococcal serotypes found most frequently in the nasopharynx were 14, 6B, 6A, 19F, 10A, 23F and 18C, which included five of the seven serotypes in the currently licensed seven-valent conjugate vaccine (PCV7); serotypes 4 and 9V were less common. Serotypes 1 and 5 were isolated rarely from the nasopharynx. A comparison of 222 nasopharyngeal isolates with 125 invasive isolates, matched for age and time to the carrier isolates, showed a similar prevalence of penicillin non-susceptible pneumococci (PNSp) (19.8% and 19.2%, respectively). PNSp serotypes were similar (6B, 14, 19F, 19 A, 23B and 23F) for carriage and invasive disease isolates. The coverage of PCV7 for carriage isolates (52.2%) and invasive isolates (62.4%) did not differ significantly (p 0.06); similarly, there was no significant difference in PCV7 coverage for carriage isolates (34.5%) and invasive isolates (28.2%) of PNSp. These data suggest that PCV7 has the potential to reduce pneumococcal carriage and the number of carriers of PNSp belonging to vaccine serotypes.

Passiflora actinia Hooker extracts and fractions induce catalepsy in mice.

Leaves from several Passiflora species are largely employed in the Brazilian folk medicine for its anxiolytic and sedative properties. In behavioral studies, to analyze the tranquillizer action of Passiflora actinia Hooker, it was noteworthy that animals treated with the hydroethanol (HE) and methanol (ME) extracts presented an abnormal postural immobility compared to control animals. That observation led to an investigation of the effects of HE and its fractions on evaluation of catalepsy in mice. The results showed that HE extract, methanol extract, the sequent aqueous crude fractions (AF), and fa, fb and fc chromatographic fractions obtained from Passiflora actinia induced catalepsy in mice. Apparently, the active principles responsible for catalepsy are present in all of the fractions of the extract.

Effects of excitatory amino acids and nitric oxide on flight behavior elicited from the dorsolateral periaqueductal gray.

Microinjection of excitatory amino acids (EAA) into the dorsolateral periaqueductal gray (dlPAG) induces flight reactions while EAA antagonists show anxiolytic effects. Part of the effects mediated by NMDA receptors may involve an increase in nitric oxide (NO) production. We showed that nitric oxide synthase (NOS) inhibitors injected into the dlPAG induced anxiolytic effects. Conversely, SIN-1, a NO donor, produced orientated flight reactions that resemble stimulation of the medial hypothalamus. This compound also produced extensive Fos-like immunoreactivity in this region and in other areas related to defensive reactions such as the medial amygdala and cingulate cortex. Since part of the effects of NO involves increases in guanylate cyclase levels, we found that intra-dlPAG injection of 8-Br-cGMP induced a brief flight reaction followed by increased locomotion. In another experiment, we showed that single or repeated restraint stress produced an increased expression of neuronal NOS in the dlPAG and other areas related to defense, as measured by in situ hybridization, diaphorase histochemistry and immunocytochemistry. Together, these data suggest that NO may participate in the modulation of defensive responses in the dlPAG.

Neuroleptic-associated autoantibodies. A prevalence study.

Antinuclear antibodies (ANA), antiphospholipid antibodies (APA), rheumatoid factor (RF), and immunoglobulin (Ig) M levels were determined in 184 male chronic psychiatric patients on long-term therapy with neuroleptics, and in 35 age-matched normal male controls. The prevalence of one or more of these autoantibodies was 70% in the neuroleptic-treated patients and 9% in the normal controls. Polyclonal IgM elevation was frequently seen among patients treated with phenothiazines. There was a significant correlation between the presence of ANA, APA, and RF; ANA and APA were more frequently associated with CPZ therapy, but the prevalence of RF was high in all treatment groups. These findings suggest that antibodies against the Fc fragment of IgG are the most common autoantibody associated with neuroleptics. Alternatively, the presence of RF could be a common finding in patients with neuropsychiatric disorders.

Microinjection of propranolol into the dorsal periaqueductal gray causes an anxiolytic effect in the elevated plus-maze antagonized by ritanserin.

The 5-HT1A/1B receptor antagonist propranolol was injected into the dorsal periaqueductal gray (DPAG) of rats exposed to the elevated plus-maze in order to investigate the participation in anxiety of 5-HT mechanisms operating in this brain region. Microinjection of D,L- or L-propranolol into the DPAG increased the percentage of total arm entries without affecting the total number of entries into either open or enclosed arms of the maze, an effect characteristic of anxiolytic drugs injected systemically. The doses of 5 nmol L-propranolol and 10 nmol D,L-propranolol caused anxiolytic effects of comparable magnitude, while the doses of 2.5 nmol of the former and 5 nmol of the latter were ineffective. Therefore, the L-isomer is likely to be the main one responsible for the pharmacological activity observed. In addition, the anxiolytic effect of 10 nmol D,L-propranolol was antagonized by 10 nmol of the 5-HT2/1C receptor antagonist ritanserin, previously injected into the DPAG. The present as well as previously reported results suggest that the anxiolytic effect of propranolol injected into the DPAG is due to increased release of 5-HT acting on post-synaptic 5-HT2 receptors, resultant from blockade of 5-HT1B autoreceptors that inhibit amine release from serotonergic nerve endings.

Evaluation of risk factors for house infestation by Triatoma infestans in Brazil.

An active entomologic survey was conducted by a team of trained health workers in a rural area endemic for Chagas' disease in central Brazil. They used pyrethrum as a flushing agent and 4,232 houses were inspected for triatomine bugs both inside and in the immediate environs. Houses with Triatoma infestans or evidence of an established colony were identified and defined as infested houses (cases). The building and environmental characteristics of 161 randomly selected infested houses were compared with 161 matched, noninfested houses (controls) that were the shortest distance from the infested house. Domestic and peridomestic potential risk factors associated with house infestation by Triatoma infestans were assessed by logistic regression analysis. Incomplete house construction (odds ratio [OR] = 2.5, 95% confidence interval [CI] = 1.5-4.1) was confirmed as a risk factor related to the presence or evidence of Triatoma infestans in the dwellings. The study also disclosed a statistically significant association between the presence of rats (OR = 1.6, 95% CI = 1.1-2.6) and indoor crop storage (OR = 2.3, 95% CI = 1.1-5.2) and house infestation. Further experimental field studies using tagged rodents should be conducted to assess their epidemiologic role in the domestic chain of Trypanosoma cruzi transmission.

Expression of neuronal nitric oxide synthase mRNA in stress-related brain areas after restraint in rats.

The objective of the present study was to investigate the expression of neuronal nitric oxide synthase (nNOS) mRNA in stress-related areas after restraint. Male Wistar rats (n=4-6/group) submitted to 2 h of restraint during one (acute) or seven (chronic) days were sacrificed 24 h after the last restraint period. In situ hybridisation was performed with oligonucleotide probes radiolabeled with (35)S. Acute restraint induced a significant increase in nNOS mRNA in the paraventricular hypothalamic nucleus (PVN), medial parvocellular part, dorsolateral periaqueductal grey (DLPAG) and medial amygdaloid nucleus, but not in the hippocampal formation. This effect persisted after chronic restraint in the PVN and DLPAG. These results suggest that restraint stress induces changes in gene expression of nNOS in areas related to stress reactions.

A "primary" thrombotic syndrome: absence of anti-phospholipid antibodies.

A patient presenting fetal loss, livedo reticularis, severe migraine crises, myocardial infarction and thrombotic vasculopathy of both external iliac arteries is described. The serologic study showed absence of antiphospholipid antibodies (aPL), suggesting that in some cases the presence of these antibodies may be a consequence of tissue damage.

Neuropsychiatric manifestations of systemic lupus erythematosus: the value of anticardiolipin, antigangliosides and antigalactocerebrosides antibodies.

In an attempt to find a serological marker for neuropsychiatric manifestations (NPM) of SLE, sera from 66 patients (classified in three groups, according to their NPM-defined, probable and without NPM) were analysed by ELISA for IgG and IgM anticardiolipin, antigangliosides and antigalactocerebrosides antibodies. A strong correlation was found between IgM antigangliosides and antigalactocerebrosides antibodies and NPM, but not with IgG class. IgM and IgG antibodies anticardiolipin were not correlated with NPM in this study. Both IgM antigangliosides and antigalactocerebrosides antibodies disappeared in seven patients with definite but clinically inactive NPM. The analysis of these autoantibodies showed an important role predictive for NPM in SLE; the negative test decreases the chance of the NPM.

Anticardiolipin antibodies in Behçet's syndrome: a predictor of a more severe disease.

A high incidence of anticardiolipin antibodies were detected in 7 of 20 patients (35%) with Behçet's Syndrome. Three patients had IgG-ab, three had IgM-ab and one had both IgG and IgM antibodies. IgG-ACA was detected mainly in patients with ocular disease (30%) and one of them also has cerebral vascular disease. A lower incidence of ACA was found in the patients taking steroids compared with the ones taking other drugs. This work draws attention to the more severe disease present in patients with ACA and also the possibility of such tests become negative in patients taking immunosuppressive drugs.

Anticardiolipin antibodies in patients with rheumatoid arthritis.

Anticardiolipin antibodies (ACA) were assayed by ELISA in 73 patients with rheumatoid arthritis. Twelve (16.48%) patients showed levels of ACA three standard deviations above the value of the control group and were considered positive; these patients were compared to the group with ACA within the normal levels regarding the following clinical and laboratorial characteristics: spontaneous abortions, central nervous system involvement, systematization and activity of disease, alterations in platelet counts, presence of antinuclear antibodies and rheumatoid factor. Significant statistical association could be demonstrated between systematization and presence of antinuclear antibodies (ANA) and positiveness to ACA (IgG, IgM or both). These findings might indicate that ACA in patients with RA could have relevance to morbidity of disease or perhaps to its pathogenesis.

Stereoselectivity of the anxiolytic effect of propranolol microinjected into the dorsal midbrain central gray.

In a previous study we have shown that microinjection of d,1-propranolol into the dorsal midbrain central gray of the rat causes an anxiolytic effect in the elevated plus-maze model which is likely to be mediated by endogenous 5-hydroxytryptamine. In the present experiment, the effects of 1- and d,1-propranolol were compared under the same experimental conditions. Both the 1-isomer and the racemic mixture increased the percentage of open arm entries without affecting the total number of entries into either open or enclosed arms of the maze, thus reproducing the selective anxiolytic effect previously described. The doses of 5 nmol 1-propranolol and 10 nmol d,1-propranolol caused anxiolytic effects of comparable magnitude, while the doses of 2.5 nmol of the former and 5 nmol of the latter were ineffective. Therefore, the 1-isomer was nearly twice as potent as the racemic mixture, thus being responsible for the pharmacological activity observed. These results are compatible with the proposal that propranol blocks stereospecific autoreceptors in serotonergic nerve endings that inhibit neurotransmitter release.

Antiphospholipid antibodies in syphilis.

1. An enzyme-linked immunosorbent assay was used to determine the phospholipid specificity of antibodies present in sera from 35 syphilis patients. 2. Based on the cross-reaction obtained against a mixture of cardiolipin, phosphatidylcholine and cholesterol that is standard for flocculation tests according to the Venereal Disease Research Laboratory (CECON, São Paulo, Brazil), all 35 patients tested positive for antibodies of the IgG class whereas 13 (37%) also had IgM antibodies for the same mixture of lipids. IgG antibodies to cardiolipin were demonstrated in 2 patients (6%) and IgM antibodies in 5 (15%). Significant levels of IgG anti-phosphatidylcholine were detected in 3 patients (9%) and IgM antibodies in 4 (11%). IgG anti-phosphatidylethanolamine antibodies were found in 1 patient (3%) and IgM antibodies in 3 (9%). Antibody binding to cardiolipin plus cholesterol or cardiolipin plus phosphatidylcholine was as effective as when the standard mixture of all 3 lipids was used. 3. A comparison with serum from systemic lupus erythematosus patients and inhibition studies using liposomes of cardiolipin or the mixture of 3 lipids suggests that there are at least 3 groups of anticardiolipin antibodies.

Tumor markers in endometriosis.

OBJECTIVES: The objective of the present study was to determine the concentrations of CA 125, CA 15-3, CA 19-9, carcioembryogenic antigen (CEA), alpha-fetoprotein (AFP) and beta-2 microglobulin (B2MG) in patients with pelvic endometriosis. METHOD: Fifty women were divided into two groups: group A (control) had no endometriosis or other diseases, and group B consisted of 35 women with pelvic endometriosis. All women were submitted to serum determination of CA 125, CA 15-3, CA 19-9, CEA, AFP and B2MG. Samples were collected during the menstrual cycle and 1 week later. RESULTS: Mean CA 125 concentrations were altered in patients with endometriosis, but all 50 patients studied presented normal CEA, AFP and B2MG concentrations. Small variations detected in CA 19-9 and CA 15-3 had no statistical significance. CONCLUSION: CA 125 is the only important marker in the diagnosis of stages III/IV of endometriosis, especially when blood samples for its determination are obtained during the first 3 days of the menstrual cycle.

Schistosoma mansoni Sambon, 1907: comparative morphological studies of some Brazilian strains.

The morphology of Schistosoma mansoni adult male worms from three strains which have been maintained in albino mice for several generations, was compared to a strain that has been isolated from the natural host Nectomys squamipes (Rodentia:Muridae) captured in Sumidouro (Rio de Janeiro State) and have been maintained in the same sylvatic rodent under laboratory conditions. Total length of specimens, distance between suckers, the number of testes and extention of testes grouping were the taxonomic characters analysed. The worms recovered from N. squamipes showed expressive differences (p < 0.01) compared to the other strains regarding the considered morphological characters. The strains that were maintained in mice presented statistical differences (p < 0.01) in several characters. Some adult worms besides the normal position of the testes also showed an atypical arrangement of these glands. It can be concluded that the morphology of adult worms may be used to distinguish S. mansoni strains and that morphological changes in adult worms are not induced by successive inoculations of a strain in mice.

[Wild rodents as experimental models of schistosomiasis mansoni: Akodon arviculoides (Rodentia: Cricetidae)]. / Roedores silvestres como modelos experimentais da esquistossomose mansônica: Akodon arviculoides (Rodentia: Cricetidae).

The experimental infection of A. arviculoides through different routes of penetration of Schistosoma mansoni cercariae (Transcutaneous and subcutaneous) was studied by the kinetics of egg elimination in stools, by the recovery and localization of adult worms (in the portal system and the mesenteric veins) and through the quantitative egg count. It was shown that A. arviculoides infection is similar to the albino mice which served as control in relation to the efficiency of penetration routes, to the adult worms habitat and the egg count. These results suggest that other aspects of the host-parasite relationship should be evaluate so that A. arviculoides may be indicated as an alternative experimental model in schistosomiasis studies.