Chagas' disease diagnosis: comparative analysis of recombinant ELISA with conventional ELISA and the haemagglutination test.

Background And Objectives: Serological screening for Chagas' disease in the blood banks of South America is carried out by using two different assays that generally show a high number of inconclusive results. To establish a combination of two tests that can minimize the number of inconclusive results, we compared a recombinant enzyme-linked immunosorbent assay (ELISA) with two conventional tests.

Materials And Methods: Serum samples from chagasic patients (n = 112), from non-chagasic individuals (n = 143) and from patients with other diseases (n = 32) were tested using three assays: recombinant ELISA (Rec-ELISA); conventional ELISA (Con-ELISA); and the indirect haemagglutination (IHA) test.

Influence of the HDL receptor SR-BI on lipoprotein metabolism and atherosclerosis.

The scavenger receptor class B type I (SR-BI) was the first molecularly well-defined cell-surface HDL receptor to be described. SR-BI mediates selective HDL cholesterol uptake by formation of a productive lipoprotein/receptor complex, which requires specific structural domains and conformation states of apolipoprotein A-I present in HDL particles. SR-BI is abundantly expressed in several tissues, including the liver, where its expression is regulated by various mechanisms, including the transcriptional activity of nuclear receptors.

Stage-specific gene expression during Trypanosoma cruzi metacyclogenesis.

The process of Trypanosoma cruzi metacyclogenesis involves the transformation of noninfective epimastigotes into metacyclic trypomastigotes, which are the pathogenic form. The analysis of stage-specific genes during T. cruzi metacyclogenesis may provide insight into the mechanisms involved in the regulation of gene expression in trypanosomatids.

Scavenger receptor class B type I-mediated protection against atherosclerosis in LDL receptor-negative mice involves its expression in bone marrow-derived cells.

Objective: Scavenger receptor class B type I (SR-BI) is a cell-surface HDL receptor that is implicated in reverse cholesterol transport and protection against atherosclerosis. We have previously demonstrated that SR-BI/apolipoprotein E double-knockout mice develop severe occlusive coronary artery disease and myocardial infarction and die at approximately 6 weeks of age. To determine if this is a general effect of a lack of SR-BI, we generated mice deficient in both SR-BI and the LDL receptor.

The role of the high-density lipoprotein receptor SR-BI in the lipid metabolism of endocrine and other tissues.

Because cholesterol is a precursor for the synthesis of steroid hormones, steroidogenic tissues have evolved multiple pathways to ensure adequate supplies of cholesterol. These include synthesis, storage as cholesteryl esters, and import from lipoproteins. In addition to endocytosis via members of the low-density lipoprotein receptor superfamily, steroidogenic cells acquire cholesterol from lipoproteins by selective lipid uptake.

Probucol prevents early coronary heart disease and death in the high-density lipoprotein receptor SR-BI/apolipoprotein E double knockout mouse.

Mice with homozygous null mutations in the high-density lipoprotein receptor SR-BI (scavenger receptor class B, type I) and apolipoprotein E genes fed a low-fat diet exhibit a constellation of pathologies shared with human atherosclerotic coronary heart disease (CHD): hypercholesterolemia, occlusive coronary atherosclerosis, myocardial infarctions, cardiac dysfunction (heart enlargement, reduced systolic function and ejection fraction, and ECG abnormalities), and premature death (mean age 6 weeks). They also exhibit a block in RBC maturation and abnormally high plasma unesterified-to-total cholesterol ratio (0.8) with associated abnormal lipoprotein morphology (lamellar/vesicular and stacked discoidal particles reminiscent of those in lecithin/cholesterol acyltransferase deficiency and cholestasis).

Structural integrity of the Golgi is temperature sensitive in conditional-lethal mutants with no detectable GM130.

At 39.5 degrees C in the temperature-sensitive, conditional-lethal mutant ldlG, glycoprotein processing is disrupted and secretion is blocked. The ultrastructure of the Golgi apparatus in ldlG cells was examined using immunofluorescence and immunoelectron microscopy.

Assessment of long-term remission of acromegaly following surgery.

Object: The criteria for remission of acromegaly following transsphenoidal adenoma resection are in evolution. In the present study the authors evaluate the utility of predicting long-term remission by reference to a single fasting growth hormone (GH) level on the 1st postoperative day.

Methods: A retrospective analysis was conducted on 181 patients with acromegaly who underwent transsphenoidal resection between 1973 and 1990 and completed a 5-year follow-up period.

Molecular evolutionary analyses of mariners and other transposable elements in fire ants (Hymenoptera: Formicidae).

Screens of a library of genomic DNA made during a recent study of the fire ant Solenopsis invicta revealed the presence of three distinct types of transposable elements (TEs). Two of the recovered sequences showed a high similarity to long-terminal repeat (LTR) retrotransposons, while the third showed a high homology to mariner elements. To investigate the distribution and relationships of mariners in related ants, we PCR-amplified these elements from additional Solenopsis species.

Neuropsychiatric effects of guanfacine in children with mild tourette syndrome: a pilot study.

The objective of this study was to evaluate the neuropsychiatric effects of the alpha-2a adrenergic agonist guanfacine in children with Tourette syndrome (TS). Twenty-four children with TS participated in a 4-week, double-blind, placebo-controlled study of guanfacine. Tic severity, neuropsychologic functioning, and parent ratings of behavior were evaluated pre- and post-treatment.

Discovery of chemical inhibitors of the selective transfer of lipids mediated by the HDL receptor SR-BI.

The high-density lipoprotein (HDL) receptor, scavenger receptor, class B, type I (SR-BI), mediates both the selective uptake of lipids, mainly cholesterol esters, from HDL to cells and the efflux of cholesterol from cells to lipoproteins. The mechanism underlying these lipid transfers is distinct from classic receptor-mediated endocytosis, but it remains poorly understood. To investigate SR-BI's mechanism of action and in vivo function, we developed a high-throughput screen to identify small molecule inhibitors of SR-BI-mediated lipid transfer in intact cells.

Identification of the N-linked glycosylation sites on the high density lipoprotein (HDL) receptor SR-BI and assessment of their effects on HDL binding and selective lipid uptake.

The murine class B, type I scavenger receptor mSR-BI, a high density lipoprotein (HDL) receptor that mediates selective uptake of HDL lipids, contains 11 potential N-linked glycosylation sites and unknown numbers of both endoglycosidase H-sensitive and -resistant oligosaccharides. We have examined the consequences of mutating each of these sites (Asn --> Gln or Thr --> Ala) on post-translational processing of mSR-BI, cell surface expression, and HDL binding and lipid transport activities. All 11 sites were glycosylated; however, disruption of only two (Asn-108 and Asn-173) substantially altered expression and function.

In vivo effects of the controlled NO donor/scavenger ruthenium cyclam complexes on blood pressure.

Ruthenium(II/III) complexes able to bind and release NO* were tested in vivo, in conscious Wistar rats instrumented for continuous blood pressure (BP) measurement and administration of in bolus injections (5 to 100 nmol/Kg i.v.) of trans-[Ru(II)Cl(NO+)(cyclam)](PF6)2 (cyclam-NO) or sodium nitroprusside (SNP).

Neurons possessing enzymes of dopamine synthesis in the mediobasal hypothalamus of rats. Topographic relations and axonal projections to the median eminence in ontogenesis.

We evaluated the topographic relations between tyrosine hydroxylase (TH)- and/or aromatic L-amino acid decarboxylase (AADC)-immunoreactive neurons in the arcuate nucleus (AN), as well as between TH- and/or AADC-immunoreactive axons in the median eminence (ME) in rats at the 21st embryonic day, 9th postnatal day, and in adulthood. The double-immunofluorescent technique in combination with confocal microscopy was used. Occasional bienzymatic neurons but numerous monoenzymatic TH- or AADC-immunoreactive neurons were observed in fetuses.

Characterization of the hypotensive effect of S-nitroso-N-acetylcysteine in normotensive and hypertensive conscious rats.

S-Nitrosothiols (RSNOs) are potent vasodilators found naturally in vivo. A variety of synthetic RSNOs have been considered as potential nitric oxide (NO) donors for biomedical applications. We have characterized the hypotensive effect of the RSNO S-nitroso-N-acetylcysteine (SNAC) in normotensive and hypertensive conscious rats.

A new inorganic vasodilator, trans-[Ru(NO)(NH(3))(4)(POEt)(3)](PF(6))(3): hypotensive effect of endothelium-dependent and -independent vasodilators in different hypertensive animals models.

The hypotensive effect of RuNO was investigated in acute and chronic hypertensive rats, as well as in normotensive rats. Acute hypertension rats were used with 30% increase on basal BP (phenylephrine, angiotensin II (Ang II), N(G)-nitro-L-arginine methyl ester (L-NAME), and adult spontaneously hypertensive rats (SHR) (basal BP 168 +/- 3 mm Hg) were used as models for chronic hypertension. Rats were implanted with catheters (iv/ia) for BP measurements and for in bolus administration of RuNO, sodium nitroprusside (SNP), and acetylcholine (Ach) (10, 20, 40 nmol/kg, iv).

Highly purified scavenger receptor class B, type I reconstituted into phosphatidylcholine/cholesterol liposomes mediates high affinity high density lipoprotein binding and selective lipid uptake.

The murine class B, type I scavenger receptor mSR-BI is a high and low density lipoprotein (HDL and LDL) receptor that mediates selective uptake of cholesteryl esters. Here we describe a reconstituted phospholipid/cholesterol liposome assay of the binding and selective uptake activities of SR-BI derived from detergent-solubilized cells. The assay, employing lysates from epitope-tagged receptor (mSR-BI-t1)-expressing mammalian and insect cells, recapitulated many features of SR-BI activity in intact cells, including high affinity and saturable (125)I-HDL binding, selective lipid uptake from [(3)H]cholesteryl ether-labeled HDL, and poor inhibition of HDL receptor activity by LDL.

Hypotensive properties and acute toxicity of trans-[Ru(NH(3))(4)P(OEt)(3)(NO)](PF(6))(3), a new nitric oxide donor.

The hypotensive effect and the acute toxicity of trans-[Ru(NH(3))(4)P(OEt)(3)(NO)](PF(6))(3) (RuNO) were investigated in conscious animals. The approximate lethal dose of RuNO is 257.5 micromol/kg in mice i.

Characterization of a mammalian Golgi-localized protein complex, COG, that is required for normal Golgi morphology and function.

Multiprotein complexes are key determinants of Golgi apparatus structure and its capacity for intracellular transport and glycoprotein modification. Three complexes that have previously been partially characterized include (a) the Golgi transport complex (GTC), identified in an in vitro membrane transport assay, (b) the ldlCp complex, identified in analyses of CHO cell mutants with defects in Golgi-associated glycosylation reactions, and (c) the mammalian Sec34 complex, identified by homology to yeast Sec34p, implicated in vesicular transport. We show that these three complexes are identical and rename them the conserved oligomeric Golgi (COG) complex.

Use of the EIE-recombinant-Chagas-biomanguinhos kit to monitor cure of human Chagas' disease.

We used the EIE-Recombinant-Chagas-Biomanguinhos kit (EIE-Rec kit) developed by the Oswaldo Cruz Foundation, Brazil, to monitor cure of chagasic patients who were treated during the acute phase of T. cruzi infection. Treated patients were previously studied by parasitological and serological tests and classified as cured patients (CP) (n = 10), dissociated patients (DP) (n = 6), and noncured patients (NCP) (n = 6).

Differentiation of tyrosine hydroxylase-synthesizing and/or aromatic L-amino acid decarboxylase-synthesizing neurons in the rat mediobasal hypothalamus: quantitative double-immunofluorescence study.

In this double-immunofluorescence study, we first quantified the neurons of the arcuate nucleus as immunoreactive (+) for tyrosine hydroxylase (TH) and/or aromatic L-amino acid decarboxylase (AADC) in rats at embryonic day 21 (E21), at postnatal day 9 (P9), and in adulthood by using conventional fluorescent or confocal microscopy. On E21, monoenzymatic (TH(+)AADC immunonegative (-) and TH(-)AADC(+)) neurons and bienzymatic (TH(+)AADC(+)) neurons accounted for 99% and 1%, respectively, of the whole neuron population expressing enzymes of dopamine synthesis. Further development was characterized by the dramatic increase in TH(+)AADC(-) dorsomedial and TH(+)AADC(+) dorsomedial populations from E21 to P9 as well as by the increase in the TH(+)AADC(+) dorsomedial population (in females) and a drop in the TH(+)AADC(-) ventrolateral and TH(+)AADC(-) dorsomedial (in males) populations from P9 to adulthood.

The effects of mutations in helices 4 and 6 of ApoA-I on scavenger receptor class B type I (SR-BI)-mediated cholesterol efflux suggest that formation of a productive complex between reconstituted high density lipoprotein and SR-BI is required for efficient lipid transport.

We have studied the effects of mutations in apoA-I on reconstituted high density lipoprotein (HDL) particle (rHDL(apoA-I)) binding to and cholesterol efflux from wild-type (WT) and mutant forms of the HDL receptor SR-BI expressed by ldlA-7 cells. Mutations in helix 4 or helix 6 of the apoA-I reduced efflux by 79 and 51%, respectively, without substantially altering receptor binding (apparent K(d) values of 1.1-4.