bluuebunny/crossref_metadata_2025 huggingface dataset:
Opposite effects of CX3CR1 receptor polymorphisms V249I and T280M on the development of acute coronary syndrome
Authors: Haschemi Arvand , Endler Georg , Zorn Gerlinde , Weyand Cornelia , Maurer Gerald , Mannhalter Christine , Wojta Johann , Wagner Oswald , Huber Kurt , Niessner Alexander , Marculescu Rodrig
Published: April 2005

Several lines of evidence suggest that the chemokine fractalkine (FKN) and its receptor CX3CR1 contribute to the accumulation of leukocytes in the atherosclerotic plaque. The M280 allele of the CX3CR1T280M polymorphism modulates leukocyte recruitment and is associated with lower prevalence of cardiovascular disease. The influence of V249I, another CX3CR1 poly-morphism, is discussed controversially. We investigated the association of the alleles M280 and I249 of CX3CR1 with coronary artery disease (CAD) and with acute coronary syndrome (ACS). Additionally, we assessed their association with the soluble ligand FKN and inflammatory activation measured by high-sensitivity C-reactive protein (hsCRP). The genotypes of the V249I and T280M polymorphisms were determined in 1152 patients with suspected CAD. 720 (62.5%) individuals showed significant CAD with an ACS prevalence of 59.3%. Using multivariate regression, we found a harmful influence of I249 (adjusted OR=1.8, P<0.03) and a protective effect of M280 (adjusted OR=0.6, P<0.04) on the occurrence of ACS in patients with CAD. Correspondingly, patients with I249 but without M280 (17%) were at elevated risk of ACS (OR=1.6, P<0.04). During ACS these patients (carrying only I249) had significantly higher circulating concentrations of FKN and high sensitivity C-reactive protein (1.9– and 1.6-fold). We found no association of the I249 or the M280 allele with the occurrence of CAD. In conclusion, I249 and M280 have opposite effects on the occurrence of ACS. The presence of I249 not“balanced” by M280 confers an elevated risk of ACS. A FKN-mediated enhanced inflammatory activation might explain this increased risk.
Associations of fibrinogen and C-reactive protein with prevalent and incident coronary heart disease are attenuated by adjustment for confounding factors
Authors: Smith George , Rumley Ann , Lowe Gordon , Ebrahim Shah , Lawlor Debbie
Published: April 2005

A cross sectional and prospective analysis of 3,745 British women aged 60–79 years at baseline was undertaken. Among these women there were 570 prevalent cases of coronary heart disease (CHD) and 151 new cases among 12,641 person-years of follow up of women who were free of CHD at baseline. Both fibrinogen and CRP were associated with indicators of socioeconomic position in childhood and adulthood and there was a cumulative effect of socioeconomic position from across the life course. The age-adjusted odds ratio (95% confidence interval) of prevalent CHD for a 1 unit (1 g/L) increase in fibrinogen was 1.29 (1.12, 1.49); with full adjustment for all potential confounding factors this attenuated to 1.09 (0.93, 1.28). The hazards ratio for incident CHD among those free of disease at baseline was 1.28 (1.00, 1.64); with full adjustment for all potential confounding factors this attenuated to 1.09 (0.84, 1.44). Similar effects of adjustment for confounding factors were seen for the associations between CRP and both prevalent and incident CHD. By contrast, the strong positive association between smoking (an established causal risk factor for CHD) and CHD was not attenuated by adjustment for life course socioeconomic position or other risk factors. We conclude that fibrinogen and CRP predict CHD but may not be causally related to it.
RNA interference in biology and disease
Authors: Sledz Carol A. , Williams Bryan R. G.
Published: April 2005

RNA interference (RNAi) is a conserved biologic response to double-stranded RNA that results in the sequence-specific silencing of target gene expression. Over the past 5 years, an intensive research effort has facilitated the rapid movement of RNAi from a relatively obscure biologic phenomenon to a valuable tool used to silence target gene expression and perform large-scale functional genomic screens. In fact, recent studies reported in this journal and others have demonstrated success using RNAi to address the role of oncogene expression in leukemia cell lines and to validate the therapeutic potential of RNAi for treating these blood disorders. In order to advance these applications and gain an appreciation for the future of RNAi both in basic research and in the treatment of diseases caused by aberrant gene expression, it is important to have an understanding of the process of RNAi and its limitations.
Lipoprotein docosapentaenoic acid is associated with serum matrix metalloproteinase-9 concentration
Authors: Solakivi Tiina , Jaakkola Olli , Kalela Anne , Pispa Mari , Salomäki Anne , Lehtimäki Terho , Höyhtyä Matti , Jokela Hannu , Nikkari Seppo T
Published: April 2005

Background

Polyunsaturated fatty acids (PUFA) are thought to play important roles in inflammation. The n-3 series is considered as anti-inflammatory, and some studies have reported increased plasma n-3 polyunsaturated fatty acid pattern in chronic inflammatory conditions. In this study we sought to clarify relationships of the levels of arachidonic acid and the polyunsaturated n-3 fatty acid compositions of isolated LDL, HDL2 and HDL3 particles with matrix metalloproteinase-9 (MMP-9), a marker of inflammation.

Results

The subjects were divided into two groups: those with lower and those with higher than the median serum MMP-9 concentration. In all lipoprotein fractions, the mean percentage of docosapentaenoic acid (C22:5n-3) was higher in the group of subjects with higher MMP-9 level than in those with lower serum MMP-9 concentration (P < 0.01 for all). Likewise, the ratio of docosapentaenoic acid to arachidonic acid (C20:4n-6) was higher in the subjects with higher MMP-9 compared with the lower MMP-9 group (P < 0.001 for all).

Conclusion

So far, the evidence for an anti-inflammatory role of the n-3 PUFA has come from dietary interventions. Our results were obtained from a free-living population and indicate that there is a positive correlation between n-3 docosapentaenoic acid and MMP-9. What had triggered the rise in MMP-9 is not known, since serum level of MMP-9 is raised in many inflammatory conditions. These findings may indicate an increased biosynthesis of n-3 polyunsaturated fatty acids in subclinical inflammation.
The biopsychosocial model and hypothyroidism
Authors: Brown Benjamin T , Bonello Rod , Pollard Henry
Published: April 2005

This paper comments on the role and emergence of the biopsychosocial model in modern medical literature and health care settings. The evolution of the biopsychosocial model and its close association with modern pain theory is also examined. This paper seeks to discuss the place of this model with respect to the management of hypothyroidism. This discussion represents a forerunner to a randomised control trial that will seek to investigate the effect of a biopsychosocial-based treatment regime on hypothyroidism.
End4/Sla2 is involved in establishment of a new growth zone inSchizosaccharomyces pombe
Authors: Castagnetti Stefania , Behrens Ralf , Nurse Paul
Published: April 2005

The rod-shaped Schizosaccharomyces pombe cell grows in a polarized fashion from opposing ends. Correct positioning of the growth zones is directed by the polarity marker Tea1 located at the cell ends where actin patches accumulate and cell growth takes place. We show that the S. pombe homologue of Saccharomyces cerevisiae SLA2, a protein involved in cortical actin organization and endocytosis, provides a link between the polarity marker and the growth machinery. In wild-type fission yeast cells, this homologue End4/Sla2 is enriched at cell ends during interphase and localizes to a medial ring at cell division, mirroring the actin localization pattern throughout the cell cycle. Proper localization relies on membrane trafficking and is independent of both the actin and microtubule cytoskeletons. End4/Sla2 is required for the establishment of new polarised growth zones, and deletion of its C-terminal talin-like domain prevents the establishment of a new growth zone after cell fission. We propose that End4/Sla2 acts downstream of the polarity marker Tea1 and is implicated in the recruitment of the actin cytoskeleton to bring about polarised cell growth.
PAK4 mediates morphological changes through the regulation of GEF-H1
Authors: Callow Marinella G. , Zozulya Sergey , Gishizky Mikhail L. , Jallal Bahija , Smeal Tod
Published: April 2005

Precise spatial and temporal regulation of Rho GTPases is required in controlling F-actin-based changes in cell morphology. The molecular mechanisms through which microtubules (MTs) modulate the activity of RhoGTPases and regulate the actin cytoskeleton are unclear. Here we show that p21-activated-kinase 4 (PAK4) mediates morphological changes through its association with the Rho-family guanine nucleotide exchange factor (GEF), GEF-H1. We show that this association is dependent upon a novel GEF-H1 interaction domain (GID) within PAK4. Further, we show that PAK4-mediated phosphorylation of Ser810 acts as a switch to block GEF-H1-dependent stress fiber formation while promoting the formation of lamellipodia in NIH-3T3 cells. We found that the endogenous PAK4-GEF-H1 complex associates with MTs and that PAK4 phosphorylation of MT-bound GEF-H1 releases it into the cytoplasm of NIH-3T3 cells, which coincides with the dissolution of stress fibers. Our observations propose a novel role for PAK4 in GEF-H1-dependent crosstalk between MTs and the actin cytoskeleton.
Inhaled Insulin: Exubera
Authors: Odegard Peggy Soule , Capoccia Kam L
Published: April 2005

OBJECTIVE:

To review the pharmacology, pharmacokinetics, efficacy, and safety of Exubera, a novel, dry-powder formulation of insulin for inhalation, and describe patient satisfaction and quality-of-life data.

DATA SOURCES:

A MEDLINE search (1966–November 2004) was conducted using the key words inhaled insulin and Exubera for clinical trials limited to human research published in English. BIOSIS Previews and the American Diabetes Association Scientific Abstracts were used for published abstract information.

STUDY SELECTION AND DATA EXTRACTION:

All available human studies of Exubera were selected for review. References of identified articles were used for additional citations.

DATA SYNTHESIS:

Exubera is a rapid-acting insulin administered by oral inhalation before meals with long-acting insulin administered subcutaneously once or twice daily for type 1 or 2 diabetes mellitus. Exubera provides similar efficacy and improved patient satisfaction compared with standard subcutaneous insulin therapy (ie, NPH twice daily with regular insulin before meals). Efficacy has also been demonstrated for Exubera when used as adjunctive therapy with oral medications for type 2 diabetes. The onset of Exubera is more rapid and its duration of action is similar to that of regular insulin. To date, Exubera administered before meals with a once-daily long-acting subcutaneous insulin (usually Ultralente) has been compared with standard subcutaneous NPH/regular insulin regimens. Comparison of premeal Exubera plus a basal long-acting insulin analog (eg, glargine) with a regimen of premeal subcutaneous rapid-acting insulin analog (eg, lispro or aspart) plus a basal long-acting insulin analog (eg, glargine) is needed to fully evaluate Exubera. Pulmonary safety appears to be maintained for up to 4 years, although there are no data, as of this writing, on the use of this agent in patients with pulmonary conditions.

CONCLUSIONS:

Exubera is an effective inhaled insulin for preprandial use in type 1 or 2 diabetes. Improved patient satisfaction over injected insulin increases its potential for use earlier in the treatment of type 2 diabetes.
Activation of Orbital and Medial Prefrontal Cortex by Methylphenidate in Cocaine-Addicted Subjects But Not in Controls: Relevance to Addiction
Authors: Volkow Nora D. , Wang Gene-Jack , Ma Yeming , Fowler Joanna S. , Wong Christopher , Ding Yu-Shin , Hitzemann Robert , Swanson James M. , Kalivas Peter
Published: April 2005

Drugs of abuse are rewarding to addicted and nonaddicted subjects, but they trigger craving and compulsive intake only in addicted subjects. Here, we used positron emission tomography (PET) and [18F]deoxyglucose to compare the brain metabolic responses (marker of brain function) of cocaine-addicted subjects (n= 21) and controls (n= 15) to identify brain regions that are uniquely activated in addicted subjects by intravenous methylphenidate (a drug that cocaine-addicted subjects report to be similar to cocaine). In parallel, we also measured the changes in dopamine (DA) induced by intravenous methylphenidate (using PET and [11C]raclopride) in the striatum and in the thalamus. Metabolic responses between groups differed significantly only in the right medial orbital prefrontal cortex [Brodmann's area (BA) 25 and medial BA 11], where methylphenidate increased metabolism in addicted subjects but decreased metabolism in controls. These changes were associated in all subjects with increased “desire for methylphenidate” and in the addicted subjects with “cocaine craving.” In addicted subjects, increases in BA 25 were also associated with mood elevation. Methylphenidate-induced increases in metabolism in the medial orbital prefrontal cortex were associated with its increase of DA in the thalamus but not in the striatum. These findings provide evidence that enhanced sensitivity of BA 25 (region involved with emotional reactivity) and BA 11 (region involved with salience attribution and motivation) in cocaine-addicted subjects may underlie the strong emotional response to the drug and the intense desire to procure it that results in craving and compulsive drug intake. It also suggests that the mesothalamic DA pathway may contribute to these processes.
Moduli space of special Lagrangians in almost Kahler spaces
Authors: MA LI
Published: April 2005

In this work we extend the McLean theorem about the moduli space of special Lagrangian submanifolds in Calabi-Yau (CY) manifolds to almost complex manifolds, which are near to the given CY manifold.
Alcohol and atherosclerosis
Authors: DA LUZ PROTASIO L. , COIMBRA SILMARA R.
Published: April 2005

Atherosclerosis is manifested as coronary artery disease (CAD), ischemic stroke and peripheral vascular disease. Moderate alcohol consumption has been associated with reduction of CAD complications. Apparently, red wine offers more benefits than any other kind of drinks, probably due to flavonoids. Alcohol alters lipoproteins and the coagulation system. The flavonoids induce vascular relaxation by mechanisms that are both dependent and independent of nitric oxide, inhibits many of the cellular reactions associated with atherosclerosis and inflammation, such as endothelial expression of vascular adhesion molecules and release of cytokines from polymorphonuclear leukocytes. Hypertension is also influenced by the alcohol intake. Thus, heavy alcohol intake is almost always associated with systemic hypertension, and hence shall be avoided. In individuals that ingest excess alcohol, there is higher risk of coronary occlusion, arrhythmias, hepatic cirrhosis, upper gastrointestinal cancers, fetal alcohol syndrome, murders, sex crimes, traffic and industrial accidents, robberies, and psychosis. Alcohol is no treatment for atherosclerosis; but it doesn't need to be prohibited for everyone. Thus moderate amounts of alcohol (1-2 drinks/day), especially red wine, may be allowed for those at risk for atherosclerosis complications.
Multidrug resistance in tumour cells: characterisation of the multidrug resistant cell line K562-Lucena 1
Authors: RUMJANEK VIVIAN M. , TRINDADE GILMA S. , WAGNER-SOUZA KAREN , MELETTI-DE-OLIVEIRA MICHELE C. , MARQUES-SANTOS LUIS F. , MAIA RAQUEL C. , CAPELLA MÁRCIA A. M.
Published: April 2005

Multidrug resistance to chemotherapy is a major obstacle in the treatment of cancer patients. The best characterised mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein. However, the resistance process is multifactorial. Studies of multidrug resistance mechanisms have relied on the analysis of cancer cell lines that have been selected and present cross-reactivity to a broad range of anticancer agents. This work characterises a multidrug resistant cell line, originally selected for resistance to the Vinca alkaloid vincristine and derived from the human erythroleukaemia cell K562. This cell line, named Lucena 1, overexpresses P-glycoprotein and have its resistance reversed by the chemosensitisers verapamil, trifluoperazine and cyclosporins A, D and G. Furthermore, we demonstrated that methylene blue was capable of partially reversing the resistance in this cell line. On the contrary, the use of 5-fluorouracil increased the resistance of Lucena 1. In addition to chemotherapics, Lucena 1 cells were resistant to ultraviolet A radiation and hydrogen peroxide and failed to mobilise intracellular calcium when thapsigargin was used. Changes in the cytoskeleton of this cell line were also observed.
Environmental risk increase due to heavy metal contamination caused by a copper mining activity in Southern Brazil
Authors: BIDONE EDISON D. , LAYBAUER LUCIANO , CASTILHOS ZULEICA C. , MADDOCK JOHN L.
Published: April 2005

The Camaquã Copper Mines (CCM) were the main sulphide deposit in Southern Brazil and have been in operation from last century to 1996. To evaluate water contamination and environmental risk increase by heavy metals from mining operations, two points on the João Dias Creek were sampled (Station 1, background area and Station 2, contaminated area). Mining activity increased the natural weakly heavy metal fluxes by approximately 5424 kg. ( ~ 60%) of the total metal flux, 1542 kg. ( ~ 49%) of dissolved and 3881 kg ( ~ 66%) of particulate metal flux. Total metal flux of anthropic origin was mostly due to Fe followed by Cu > Zn > Mn whereas Cd, As and Pb fluxes were negligible. The potential human health hazards and risk assessment related to daily intake of water from João Dias Creek are mostly due to Mn and should be of concern for the contaminated area. The ingestion of water from station 2 represents incremental risks of 130% and 59% respectively, considering the non-carcinogenic and the carcinogenic effects. The real increase of human health hazards may be greater than those related to the total concentrations since Mn and As dissolved concentrations were 5.5 and 2.0 higher than acceptable, respectively.
Characterization and genesis of waterfalls of the Presidente Figueiredo region, Northeast State of Amazonas, Brazil
Authors: NOGUEIRA AFONSO C. R. , SARGES ROSEANE R.
Published: April 2005

The waterfalls of the Presidente Figueiredo municipality represent a fascinating natural scenery of northeast state of Amazonas, northern Brazil. The falls, generally less than 10m high, are developed on siliciclastic rocks of the Nhamundá (Lower Silurian), and Manacapuru (Upper Silurian - Lower Devonian) formations. Morphological and structural analyses of these features indicate that most of them originated through Quaternary neotectonics and are installed in NE-trending normal fault escarpments. Waterfalls also developed within pseudokarstic features, but are less frequent. The origin of the Presidente Figueiredo waterfalls probably goes back to the Neogene, when the region was submitted to laterization processes associated with a humid climate and a dense rainforest. These conditions favored the development of caves in quartzarenites of the Nhamundá Formation. During the Quaternary, the region was subjected to NE-trending normal faulting which displaced laterite layers, rivers and streams giving rise to waterfalls. These climatic and tectonic phenomena promoted intense relief dissection, as indicated by fault escarpment retreat and cave dismantlement, responsible for the present-day morphologic configuration.
Rigidity theorems of Clifford Torus
Authors: SOUSA JR. LUIZ A. M.
Published: April 2005

Let M be an n-dimensional closed minimally immersed hypersurface in the unit sphere Sn + 1. Assume in addition that M has constant scalar curvature or constant Gauss-Kronecker curvature. In this note we announce that if M has (n - 1) principal curvatures with the same sign everywhere, then M is isometric to a Clifford Torus .
On the geometry of Poincaré's problem for one-dimensional projective foliations
Authors: SOARES MARCIO G.
Published: April 2005

We consider the question of relating extrinsic geometric characters of a smooth irreducible complex projective variety, which is invariant by a one-dimensional holomorphic foliation on a complex projective space, to geometric objects associated to the foliation.
On Huygens' principle for Dirac operators associated to electromagnetic fields
Authors: CHALUB FABIO A.C.C.
Published: April 2005

We study the behavior of massless Dirac particles, i.e., solutions of the Dirac equation with m = 0 in the presence of an electromagnetic field. Our main result (Theorem 1) is that for purely real or imaginary fields any Huygens type (in Hadamard's sense) Dirac operators is equivalent to the free Dirac operator, equivalence given by changes of variables and multiplication (right and left) by nonzero functions.
Volcanism and stratigraphy of the Neoproterozoic Campo Alegre Basin, SC, Brazil
Authors: CITRONI SERGIO B. , BASEI MIGUEL A. S. , SIGA JR. OSWALDO , REIS NETO JOSÉ M. DOS
Published: April 2005

The depositional succession of the Campo Alegre Basin (Santa Catarina - southern Brazil) was investigated having the evolution of the volcanic activity as background. The different stratigraphic units are interpreted as belonging to different volcanic stages: Bateias Formation, conglomerates and sandstones, related with a pre-volcanic stage; Campo Alegre Group, at the main volcanic stage, with each different formation corresponding to different episodes of volcanism - Rio Negrinho Formation, corresponding to the basic volcanism, Avenca Grande Formation to ignimbritic event, Serra de São Miguel Formation to the acid volcanism and Fazenda Uirapuru Formation, related to an explosive event; Rio Turvo and Arroio Água Fria formations correspond respectively to inner and extra-caldera deposits.
Umbilic and Tangential Singularities on Configurations of Principal Curvature Lines
Authors: GARCIA RONALDO , SOTOMAYOR JORGE
Published: April 2005

In this paper is studied the relationship between quadratic tangencies of principal lines with the boundary of a surface and the Darbouxian umbilics of a smooth boundaryless surface which approximates it through the process of thickening and smoothing defined here.
A taxonomic bibliography of the South American snakes of the Crotalus durissus complex (Serpentes, Viperidae)
Authors: VANZOLINI PAULO E. , CALLEFFO MYRIAM E.V.
Published: April 2005

A survey is made of the taxonomic literature on South American rattlesnakes (genus Crotalus, family Viperidae). Two main areas are emphasized: the attribution of the names proposed in the eighteenth century by Linnaeus and Laurenti, and the current scheme of division in subspecies. The attribution of names is examined based on the original descriptions and on relevant previous and contemporary literature. The presently adopted scheme, proposed by Klauber (1941, 1972) is found not entirely satisfactory, but reasonable enough - besides being hallowed by use. The scheme of geographical differentiation, intrinsically important and with broad practical implications (differentiation of the venom) is found to be the culmination of a long series of deficient analyses, and in urgent need of proper investigation.
The lizard cerebral cortex as a model to study neuronal regeneration
Authors: LOPEZ-GARCIA CARLOS , MOLOWNY ASUNCION , NACHER JUAN , PONSODA XAVIER , SANCHO-BIELSA FRANCISCO , ALONSO-LLOSA GREGORI
Published: April 2005

The medial cerebral cortex of lizards, an area homologous to the hippocampal fascia dentata, shows delayed postnatal neurogenesis, i.e., cells in the medial cortex ependyma proliferate and give rise to immature neurons, which migrate to the cell layer. There, recruited neurons differentiate and give rise to zinc containing axons directed to the rest of cortical areas, thus resulting in a continuous growth of the medial cortex and its zinc-enriched axonal projection. This happens along the lizard life span, even in adult lizards, thus allowing one of their most important characteristics: neuronal regeneration. Experiments in our laboratory have shown that chemical lesion of the medial cortex (affecting up to 95% of its neurons) results in a cascade of events: first, massive neuronal death and axonal-dendritic retraction and, secondly, triggered ependymal-neuroblast proliferation and subsequent neo-histogenesis and regeneration of an almost new medial cortex, indistinguishable from a normal undamaged one. This is the only case to our knowledge of the regeneration of an amniote central nervous centre by new neuron production and neo-histogenesis. Thus the lizard cerebral cortex is a good model to study neuronal regeneration and the complex factors that regulate its neurogenetic, migratory and neo-synaptogenetic events.
"In vivo" toxicity of a truncated version of the Drosophila Rst-IrreC protein is dependent on the presence of a glutamine-rich region in its intracellular domain
Authors: MACHADO RICARDO C. , PEREIRA RODRIGO N.R. , COSTA MARA S.A. , RAMOS RICARDO GUELERMAN P.
Published: April 2005

The roughest-irregular chiasm C ( rst-irreC) gene of Drosophila melanogaster encodes a transmembrane glycoprotein containing five immunoglobulin-like domains in its extracellular portion and an intracytoplasmic tail rich in serine and threonine as well some conserved motifs suggesting signal transduction activity. In the compound eye, loss-of-function rst-irreC mutants lack the characteristic wave of programmed cell death happening in early pupa and which is essential for the elimination of the surplus interommatidial cells. Here we report an investigation on the role played by the Rst-irreC molecule in triggering programmed cell death. "In vivo" transient expression assays showed that deletion of the last 80 amino acids of the carboxyl terminus produces a form of the protein that is highly toxic to larvae. This toxicity is suppressed if an additional 47 amino acid long, glutamine-rich region ("opa-like domain"), is also removed from the protein. The results suggest the possibility that the opa-like domain and the carboxyl terminus act in concert to modulate rst-irreC function in apoptosis, and we discuss this implication in the context of the general mechanisms causing glutamine-rich neurodegenerative diseases in humans.
Short and long period optimization of drug doses in the treatment of AIDS
Authors: CAETANO MARCO A. L. , YONEYAMA TAKASHI
Published: April 2005

Numerical optimization techniques are useful in solving problems of computing the best inputs for systems described by mathematical models and when the objectives can be stated in a quantitative form. This work concerns the problem of optimizing the drug doses in the treatment of AIDS in terms of achieving a balance between the therapeutic response and the side effects. A mathematical model describing the dynamics of HIV viruses and CD4 cells is used to compute the short term optimal drug doses in the treatments of patients with AIDS by a direct method of optimization using a cost function of Bolza type. The model parameters were fitted to actual published clinical data. In order to simplify the numerical procedures, the control law is expressed as a series and the sub-optimal control is obtained by truncating the higher terms. When the patient reaches a clinically satisfactory state, the LQR - Linear Quadratic Regulator technique is used to determine the long period maintenance doses for the drugs. The doses computed using the LQR technique tend to be smaller than equivalent constant-dose therapy in terms of increase in the counts of CD4+T cells and reduction of the density of free viruses.
Voltammetric characteristics of miconazole and its cathodic stripping voltammetric determination
Authors: PEREIRA FRANCISCO C. , STRADIOTTO NELSON R. , ZANONI MARIA VALNICE B.
Published: April 2005

Miconazole is reduced at mercury electrode above pH 6 involving organometallic compound formation, responsible for an anomalous polarographic behavior. The electrodic process presents a large contribution of the adsorption effects. The drug can be determined by cathodic stripping voltammetry from 8.0 x 10-8 to 1, 5 x 10-6 molL-1 in Britton-Robinson buffer pH 8.0, when pre-accumulated for 30s at an accumulation potential of 0V. A relative standard deviation of 3.8% was obtained for ten measurements of 1.0 x 10-7 molL-1 miconazole in B-R buffer pH 8.0 and a limit detection of 1, 7 x 10-8 molL-1 was determined using 60s of deposition time and scan rate of 100 mVs-1. The proposed method is simple, precise and it was applied successfully for the determination of the miconazole in pure form and in commercial formulations, showing mean recoveries of 99.7-98.4%.
Adenosine as a signaling molecule in the retina: biochemical and developmental aspects
Authors: PAES-DE-CARVALHO ROBERTO
Published: April 2005

The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.
Neurotransmitter regulation of neural development: acetylcholine and nicotinic receptors
Authors: TORRÃO ANDRÉA S. , BRITTO LUIZ R.G.
Published: April 2005

Several neurotransmitter systems have been related to developmental processes during the past decade. In this review, we discuss the evidence that the nicotinic acetylcholine receptors could have an additional function during development that may be unrelated to their role in cholinergic neurotransmission in the vertebrate brain. Both temporal expression data and in vitro and in vivo studies with nicotinic agonists and antagonists have provided direct support for a role of nicotinic receptors in neural developmental processes such as neurite outgrowth and differentiation. A similar picture has emerged for other neurotransmitter and receptor systems as well, which generates a new view of neural processes during both development and mature life.
Silica enrichment, graphic granite and aquamarine growth: a new exploration guide
Authors: RAO A. BHASKARA
Published: April 2005

Granitic pegmatites are traditionally known to contain graphic, perthitic and myrmekitic intergrowths related to quartz and K- and Na- feldspars. They are further considered to characterise the pegmatite types distinguishing them from the granites and other related plutonic rock types. Graphic granite is accepted also as a synonym to granitic pegmatite. Systematic studies, by the author and colleagues, on the granitic pegmatite gem deposits have permitted the definition of two aquamarine gem provinces in ENE Brazil, one in the NeoProterozoic and the other in the Archaean sequences. Potash feldspars in the pegmatites in the former show perthitic intergrowths, whereas in the latter graphic intergrowth dominates with anomalously coarse centimetric quartz along the cleavages of K-feldspar. Several granitic pegmatites hosted in Archaean complex, in Lages Pintadas Aquamarine Province, Santa Cruz, RN State, present this texture-structure. Graphic intergrowth is attributed to the eutectic crystallization, succeeded by hydrothermal fluids with silica enrichment permitting the growth through diffusion and nucleation of quartz and along cleavages of potash feldspar. In the Archaean terrain, the abundance of recycled chert forming metapsammitic migmatites traversed by numerous quartz veins and coarse graphic granites, has contributed to the growth of beryl and also the aquamarines.
Role of laminin bioavailability in the astroglial permissivity for neuritic outgrowth
Authors: TARDY MARCIENNE
Published: April 2005

The mechanisms involved in the failure of an adult brain to regenerate post-lesion remain poorly understood. The reactive gliosis which occurs after an injury to the CNS and leads to the glial scar has been considered as one of the major impediments to neurite outgrowth and axonal regeneration. A glial scar consists mainly of reactive, hypertrophic astrocytes. These reactive cells acquire new properties, leading to A non-permissive support for neurons. Astrogial reactivity is mainly characteriized by a high overexpression of the major component of the gliofilaments, the glial fibrillary acidic protein (GFAP). This GFAP overexpression is related to the astroglial morphological response to injury. We hypothesized that modulation of GFAP synthesis, reversing the hypertrophic phenotype, might also reverse the blockage of neuritic outgrowth observed after a lesion. In this article, we review findings of our group, confirming our hypothesis in a model of lesioned neuron-astrocyte cocultures. We demonstrate that permissivity for neuritic outgrowth is related to phenotypic changes induced in reactive astrocytes transfected by antisense GFAP-mRNA. We also found that this permissivity was related to a neuron-regulated extracellular laminin bioavailability.
A note on the occurrence of the encrusting foraminifera Homotrema rubrum in reef sediments from two distinctive hydrodynamic settings
Authors: MACHADO ALTAIR J. , MORAES SIMONE S.
Published: April 2005

Sediment samples from two different reef environments were analyzed for their foraminiferal content: the Sioba/Rio do Fogo reefs, located in a broad shallow shelf dominated by strong currents (Rio Grande do Norte State), and the Praia do Forte reefs, located in a narrow shelf under the influence of wind-induced waves (Bahia State). The recorded foraminiferal fauna, from forty-six samples, is represented by 113 species, being the encrusting species Homotrema rubrum present in nine samples from the Sioba/Rio do Fogo reefs and in 11 samples from Praia do Forte reefs. Homotrema fragments recovered from Sioba/Rio do Fogo are mostly polished with rounded edges (51.59%) and some have a whitish color, whereas the specimens from Praia do Forte reefs are predominantly composed of reddish fragments (82.41%) with sharpened points (63.88%). The high wave energy on the reef environment of Praia do Forte is responsible for the fragmentation of living Homotrema tests (red color), which are deposited near to their source area. The effects of the strong current system operating in the broad continental shelf of Sioba/Rio do Fogo is the major cause of sediment reworking, producing polished grains accumulated in its reef surroundings.
Seasonal variation in the essential oil of Pilocarpus microphyllus Stapf.
Authors: TAVEIRA FRANCISCA S. N. , ANDRADE ELOISA H. A. , LIMA WATERLOO N. , MAIA JOSÉ G. S.
Published: April 2005

The essential oils of the leaves and fine stems of Pilocarpus microphyllus, collected on iron mineralized soil of the Serra de Carajás, Southeast of Pará State, Brazil, during the rainy and dry seasons, were obtained by hydrodistillation and analyzed by GC-MS. The main identified compounds were 2-tridecanone, beta-caryophyllene, 2-pentadecanone, caryophyllene oxide and germacrene D. Their percentage contents varied with the season, the greater values having been detected mainly in the rainy season. For 2-tridecanone and beta-caryophyllene the higher values were observed in the fine stem oils for the former, and in the leaf oils for the latter. For 2-pentadecanone, caryophyllene oxide and germacrene D they were also in the leaf oils. In general, the leaf oils were very distinguishable from those of fine stem oils, even in the same specimen.
Scattering of electromagnetic plane waves by a buried vertical dike
Authors: Batista Lurimar S. , Sampaio Edson E. S.
Published: April 2005

The complete and exact solution of the scattering of a TE mode frequency domain electromagnetic plane wave by a vertical dike under a conductive overburden has been established. An integral representation composed of one-sided Fourier transforms describes the scattered electric field components in each one of the five media: air, overburden, dike, and the country rocks on both sides of the dike. The determination of the terms of the series that represents the spectral components of the Fourier integrals requires the numerical inversion of a sparse matrix, and the method of successive approaches. The zero-order term of the series representation for the spectral components of the overburden, for given values of the electrical and geometrical parameters of the model, has been computed. This result allowed to determine an approximate value of the variation of the electric field on the top of the overburden in the direction perpendicular to the strike of the dike. The results demonstrate the efficiency of this forward electromagnetic modeling, and are fundamental for the interpretation of VLF and Magnetotelluric data.
Delineating shallow Neogene deformation structures in northeastern Pará State using Ground Penetrating Radar
Authors: Rossetti Dilce F.
Published: April 2005

The geological characterization of shallow subsurface Neogene deposits in northeastern Pará State using Ground Penetrating Radar (GPR) revealed normal and reverse faults, as well as folds, not yet well documented by field studies. The faults are identified mostly by steeply-dipping reflections that sharply cut the nearby reflections causing bed offsets, drags and rollovers. The folds are recognized by reflections that are highly undulating, configuring broad concave and convex-up features that are up to 50 m wide and 80 to 90 ns deep. These deformation structures are mostly developed within deposits of Miocene age, though some of the faults might continue into younger deposits as well. Although the studied GPR sections show several diffractions caused by trees, differential degrees of moisture, and underground artifacts, the structures recorded here can not be explained by any of these ''noises''. The detailed analysis of the GPR sections reveals that they are attributed to bed distortion caused by brittle deformation and folding. The record of faults and folds are not widespread in the Neogene deposits of the Bragantina area. These GPR data are in agreement with structural models, which have proposed a complex evolution including strike-slip motion for this area from the Miocene to present.
Metamorphic evolution and U-Pb zircon SHRIMP geochronology of the Belizário ultramafic amphibolite, Encantadas Complex, southernmost Brazil
Authors: Hartmann Léo A. , Santos João O.S. , Leite Jayme A.D. , Porcher Carla C. , Mcnaughton Neal J.
Published: April 2005

The integrated investigation of metamorphism and zircon U-Pb SHRIMP geochronology of the Belizário ultramafic amphibolite from southernmost Brazil leads to a better understanding of the processes involved in the generation of the Encantadas Complex. Magmatic evidence of the magnesian basalt or pyroxenite protolith is only preserved in cores of zircon crystals, which are dated at 2257 ± 12 Ma. Amphibolite facies metamorphism M1 formed voluminous hornblende in the investigated rock possibly at 1989 ± 21 Ma. This ultramafic rock was re-metamorphosed at 702±21 Ma during a greenschist facies eventM2; the assemblage actinolite + oligoclase + microcline + epidote + titanite + monazite formed by alteration of hornblende. The metamorphic events are probably related to the Encantadas Orogeny (2257±12 Ma) and Camboriú Orogeny (~ 1989 Ma) of the Trans-Amazonian Cycle, followed by an orogenic event (702±21 Ma) of the Brasiliano Cycle. The intervening cratonic period (2000-700 Ma) corresponds to the existence of the Supercontinent Atlantica, known regionally as the Rio de la Plata Craton.
Cremophor EL stimulates mitotic recombination in uvsH//uvsH diploid strain of Aspergillus nidulans
Authors: Busso Cleverson , Castro-Prado Marialba A. A.
Published: April 2005

Cremophor EL is a solubilizer and emulsifier agent used in the pharmaceutical and foodstuff industries. The solvent is the principal constituent of paclitaxel's clinical formulation vehicle. Since mitotic recombination plays a crucial role in multistep carcinogenesis, the study of the recombinagenic potential of chemical compounds is of the utmost importance. In our research genotoxicity of cremophor EL has been studied by using an uvsH//uvsH diploid strain of Aspergillus nidulans. Since it spends a great part of its cell cycle in the G2period, this fungus is a special screening system for the study of mitotic recombination induced by chemical substances. Homozygotization Indexes (HI) for paba and bi markers from heterozygous B211//A837 diploid strain were determined for the evaluation of the recombinagenic effect of cremophor EL. It has been shown that cremophor EL induces increase in mitotic crossing-over events at nontoxic concentrations (0.05 and 0.075% v/v).
Permian plants from the Chutani Formation (Titicaca Group, Northern Altiplano of Bolivia): I. Genera Pecopteris and Asterotheca
Authors: Vieira Carlos E. L. , Iannuzzi Roberto , Guerra-Sommer Margot , Díaz-Matrínez Enrique , Grader George W.
Published: April 2005

Fossil plants belonging to the morphogenera Glossopteris, Pecopteris and Asterotheca were collected from the upper part of the Chutani Formation (Titicaca Group), near the town of San Pablo de Tiquina, on the southeastern shore of Lake Titicaca (northern Altiplano, Bolivia). Here we report the analysis of fern-type foliage found at this location. Three species of pecopterid fronds are identified: Pecopteris dolianitii Rohn and Rösler, P. cf. P. cadeadensis Rohn and Rösler, and P. cf. P. pedrasica Read. All these species are typically found in Permian deposits of the Paraná Basin in southern Brazil. Despite the poor preservation of the material, a fertile specimen could be studied and was determined as Asterotheca sp. The paleoenvironmental and paleoecological implications of this new find are briefly analyzed.
Benthic foraminifera distribution in high polluted sediments from Niterói Harbor (Guanabara Bay), Rio de Janeiro, Brazil
Authors: Vilela Claudia G. , Batista Daniele S. , Batista-Neto José A. , Crapez Mirian , Mcallister John J.
Published: April 2005

Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Low concentrations in the benthic foraminifera as well as the dominance of indicative species such as Ammonia tepida, Buliminella elegantissima and Bolivina lowmani can be associated with an environment under stress. In addition, the occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long-term environmental impacts in a coastal region.
Evolution of acoustic communication in crickets: phylogeny of Eneopterinae reveals an adaptive radiation involving high-frequency calling (Orthoptera, Grylloidea, Eneopteridae)
Authors: Robillard Tony , Desutter-Grandcolas Laure
Published: April 2005

Evolution of dominant frequencies in songs of Eneopterinae crickets was studied with respect to phylogeny. Two characters are optimized on the tree: the first describes the frequency resulting from the vibration of the harp (Fda), and the second is due to the vibration of other tegminal areas (Fdb). Fda was found to be relatively stable through the subfamily. Its low ancestral state is replaced by a high Fda only once, resulting in high-frequency calling in [Cardiodactylus (Lebinthus-Agnotecous)]. A high Fdb component is added to the low ancestral Fda in Eneoptera guyanensis, resulting in frequency modulation. The onset of high Fd in this first subclade is accompanied by a high cladogenesis rate, which supports a hypothesis of adaptive radiation for high frequencies. The effectiveness of high-frequency calling is discussed in relation to the species behavior ecology.
Bioacoustic investigations and taxonomic considerations on the Cicadetta montana species complex (Homoptera: Cicadoidea: Tibicinidae)
Authors: Gogala Matija , Trilar Tomi
Published: April 2005

Recent bioacoustic investigations have shown that Cicadetta montana Scopoli 1772 is a complex of morphologically similar sister species that are best characterized by their song patterns. At the type locality of C. montana, only mountain cicadas with simple, long lasting song phrases were heard, recorded and collected. Therefore, we have good reasons to suggest that this type of song is characteristic for C. montana s. str. Boulard described a song of C. montana from France with phrases composed of a long and a short echeme; this type of song is characteristic for cicadas morphologically corresponding to C. montana var. brevipennis Fieber 1876; we suggest to raise this taxon to species level. On the basis of specific song, Puissant and Boulard described C. cerdaniensis from Pyrénées. A similar case was the discovery and description of C. montana macedonica Schedl 1999 from Macedonia; since these Macedonian cicadas are sympatric with at least two other cryptic species in the C. montana group and molecular investigations showed substantial genetic differences between C. macedonica and C. montana or C. brevipennis, we conclude that this taxon should also be raised to species level. Songs of closely related C. podolica and Korean mountain cicada are presented as well.
Variation in the behavioral responses of Budgerigars Melopsittacus undulatus to an alarm call in relation to sex and season
Authors: Nicolas Gérard , Fraigneau Cloé , Aubin Thierry
Published: April 2005

In the Budgerigar Melopsittacus undulatus, the significance of a conspecific alarm call was investigated in two seasons, winter and spring. Two qualitatively different behavioral responses were displayed by the receivers in reply to playbacks: call(s) and/or taking flight(s). The comparative analysis of the number of birds responding to the alarm and to the control signals revealed two major facts: 1) in both seasons, the responses to the alarm signal were only observed for females, not for males, 2) qualitatively, females exhibited a great inter-season variability in their behavioral responses to the hearing of an alarm call. In winter, the females were more predisposed to emit acoustic responses while in spring they mainly took flight.