Adora2A downregulation promotes caffeine neuroprotective effect against LPS-induced neuroinflammation in the hippocampus

Caffeine has been extensively studied in the context of CNS pathologies as many researchers have shown that consuming it reduces pro-inflammatory biomarkers, potentially delaying the progression of neurodegenerative pathologies. Several lines of evidence suggest that adenosine receptors, especially A1 and A2A receptors, are the main targets of its neuroprotective action. We found that caffeine pretreatment 15 min before LPS administration reduced the expression of Il1b in the hippocampus and striatum. The harmful modulation of caffeine-induced inflammatory response involved the downregulation of the expression of A2A receptors, especially in the hippocampus. Caffeine treatment alone promoted the downregulation of the adenosinergic receptor Adora2A; however, this promotion effect was reversed by LPS. Although administering caffeine increased the expression of the enzymes DNA methyltransferases 1 and 3A and decreased the expression of the demethylase enzyme Tet1, this effect was reversed by LPS in the hippocampus of mice that were administered Caffeine + LPS, relative to the basal condition; no significant differences were observed in the methylation status of the promoter regions of adenosine receptors. Finally, the bioinformatics analysis of the expanded network demonstrated the following results: the Adora2B gene connects the extended networks of the adenosine receptors Adora1 and Adora2A; the Mapk3 and Esr1 genes connect the extended Adora1 network; the Mapk4 and Arrb2 genes connect the extended Adora2A network with the extended network of the proinflammatory cytokine Il1β. These results indicated that the anti-inflammatory effects of acute caffeine administration in the hippocampus may be mediated by a complex network of interdependencies between the Adora2B and Adora2A genes.

Development of cobalt (Co)-doped monetites for bone regeneration

Cobalt-doped monetite powders were synthesized by coprecipitation method under a cobalt nominal content between 2 and 20 mol % of total cation. Structural characterization of samples was performed by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. XRD results indicated that the Co-doped samples exhibited a monetite single-phase with the cell parameters and crystallite size dependent on the amount of substitutional element incorporated into the triclinic crystalline structure. Cell viability and adhesion assays using pre-osteoblastic cells showed there is no toxicity and the RTqPCR analysis showed significant differences in the expression for osteoblastic phenotype genes, showing a potential material for the bone regeneration.

Osteogenic differentiation and reconstruction of mandible defects using a novel resorbable membrane: An in vitro and in vivo experimental study

To evaluate the cellular response of both an intact fish skin membrane and a porcine-derived collagen membrane and investigate the bone healing response of these membranes using a translational, preclinical, guided-bone regeneration (GBR) canine model. Two different naturally sourced membranes were evaluated in this study: (i) an intact fish skin membrane (Kerecis Oral®, Kerecis) and (ii) a porcine derived collagen (Mucograft®, Geistlich) membrane, positive control. For the in vitro experiments, human osteoprogenitor (hOP) cells were used to assess the cellular viability and proliferation at 24, 48, 72, and 168 h. ALPL, COL1A1, BMP2, and RUNX2 expression levels were analyzed by real-time PCR at 7 and 14 days. The preclinical component was designed to mimic a GBR model in canines (n = 12). The first step was the extraction of premolars (P1-P4) and the 1st molars bilaterally, thereby creating four three-wall box type defects per mandible (two per side). Each defect site was filled with bone grafting material, which was then covered with one of the two membranes (Kerecis Oral® or Mucograft®). The groups were nested within the mandibles of each subject and membranes randomly allocated among the defects to minimize potential site bias. Samples were harvested at 30-, 60-, and 90-days and subjected to computerized microtomography (μCT) for three-dimensional reconstruction to quantify bone formation and graft degradation, in addition to histological processing to qualitatively analyze bone regeneration. Neither the intact fish skin membrane nor porcine-based collagen membrane presented cytotoxic effects. An increase in cell proliferation rate was observed for both membranes, with the Kerecis Oral® outperforming the Mucograft® at the 48- and 168-hour time points. Kerecis Oral® yielded higher ALPL expression relative to Mucograft® at both 7- and 14-day points. Additionally, higher COL1A1 expression was observed for the Kerecis Oral® membrane after 7 days but no differences were detected at 14 days. The membranes yielded similar BMP2 and RUNX2 expression at 7 and 14 days. Volumetric reconstructions and histologic micrographs indicated gradual bone ingrowth along with the presence of particulate bone grafts bridging the defect walls for both Kerecis Oral® and Mucograft® membranes, which allowed for the reestablishment of the mandible shape after 90 days. New bone formation significantly increased from 30 to 60 days, and from 60 to 90 days in vivo, without significant differences between membranes. The amount of bovine grafting material (%) within the defects significantly decreased from 30 to 90 days. Collagen membranes led to an upregulation of cellular proliferation and adhesion along with increased expression of genes associated with bone healing, particularly the intact fish skin membrane. Despite an increase in the bone formation rate in the defect over time, there was no significant difference between the membranes.

MicroRNA biogenesis machinery activation and lncRNA and REST overexpression as neuroprotective responses to fight inflammation in the hippocampus

Brain Long non-coding RNA (lncRNA) and microRNAs (miRs) play essential roles in the regulation of several important biological processes, including neuronal activity, cognitive processes, neurogenesis, angiogenesis, and neuroinflammation. In this context, the transcriptional repressor, RE1 silencing transcription factor (Rest), acts regulating the expression of neuronal genes as well as of lncRNAs and multiple miRNAs in the central nervous system. Nevertheless, its role in neuroinflammation was less explored. Here, we demonstrate, using an in vivo model of neuroinflammation induced by i.p. injection of LPS (0.33 mg/kg), that neuroinflammation increases gene expression of pro-inflammatory cytokines concomitant with the native and truncated forms of Rest and of non-coding RNAs. Additionally, the increased expression of enzymes Drosha ribonuclease III) (Drosha), Exportin 5 (Xpo5) and Endoribonuclease dicer (Dicer), associated with high expression of neuroprotective miRs 22 and 132 are indicative that the activation of biogenesis of miRs in the hippocampal region is a Central Nervous System (CNS) protective mechanism for the deleterious effects of neuroinflammation. Our results indicate that positive regulation of Rest gene expression in the hippocampal region by neuroinflammation correlates directly with the expression of miRs 22 and 132 and inversely with miR 335. In parallel, the confirmation of the possible alignment between the lncRNAs with miR 335 by bioinformatics corroborates with the sponge effect of Hottip and Hotair hybridizing and inhibiting the pro-inflammatory action of miR 335. This suggests the existence of a possible correlation between the activation of miR biogenesis machinery with increased expression of the transcription factor Rest, contributing to neuroprotection.

Cyclopamine targeting hedgehog modulates nuclear control of the osteoblast activity

It is known that cellular events underlying the processes of bone maintenance, remodeling, and repair have their basis in the embryonic production of bone. Shh signaling is widely described developing important morphogenetic control in bone by modifying the activity of osteoblast. Furthermore, identifying whether it is associated with the modulation of nuclear control is very important to be the basis for further applications. Experimentally, osteoblasts were exposed with cyclopamine (CICLOP) considering up to 1 day and 7 days, here considered an acute and chronic responses respectively. Firstly, we have validated the osteogenic model in vitro by exposing the osteoblasts to classical differentiating solution up to 7 days to allow the analysis of alkaline phosphatase and mineralization. Conversely, our data shows that differentiating osteoblasts present higher activity of inflammasome-related genes, while Shh signaling members were lower, suggesting a negative feedback between them. Thereafter, to better know about the role of Shh signaling on this manner, functional assays using CICLOP (5 μM) were performed and the data validates the previously hypothesis that Shh represses inflammasome related genes activities. Altogether, our data supports the anti-inflammatory effect of Shh signaling by suppressing Tnfα, Tgfβ and inflammasome related genes during osteoblast differentiation, and this comprehension might support the understanding the molecular and cellular mechanisms related in bone regeneration by reporting molecular-related osteoblast differentiation.

Titanium-Enriched Medium Promotes Environment-Induced Epigenetic Machinery Changes in Human Endothelial Cells

It is important to understand whether endothelial cells are epigenetically affected by titanium-enriched media when angiogenesis is required during bone development and it is expected to be recapitulated during osseointegration of biomaterials. To better address this issue, titanium-enriched medium was obtained from incubation of titanium discs for up to 24 h as recommended by ISO 10993-5:2016, and further used to expose human umbilical vein endothelial cells (HUVECs) for up to 72 h, when the samples were properly harvested to allow molecular analysis and epigenetics. In general, our data show an important repertoire of epigenetic players in endothelial cells responding to titanium, reinforcing protein related to the metabolism of acetyl and methyl groups, as follows: Histone deacetylases (HDACs) and NAD-dependent deacetylase sirtuin-1 (Sirt1), DNA methyltransferases (DNMTs) and ten-eleven translocation (TET) methylcytosine dioxygenases, which in conjunction culminate in driving chromatin condensation and the methylation profile of DNA strands, respectively. Taking our data into consideration, HDAC6 emerges as important player of this environment-induced epigenetic mechanism in endothelial cells, while Sirt1 is required in response to stimulation of reactive oxygen species (ROS) production, as its modulation is relevant to vasculature surrounding implanted devices. Collectively, all these findings support the hypothesis that titanium keeps the surrounding microenvironment dynamically active and so affects the performance of endothelial cells by modulating epigenetics. Specifically, this study shows the relevance of HDAC6 as a player in this process, possibly correlated with the cytoskeleton rearrangement of those cells. Furthermore, as those enzymes are druggable, it opens new perspectives to consider the use of small molecules to modulate their activities as a biotechnological tool in order to improve angiogenesis and accelerate bone growth with benefits of a fast recovery time for patients.

Non-coding RNAs repressive role in post-transcriptional processing of RUNX2 during the acquisition of the osteogenic phenotype of periodontal ligament mesenchymal stem cells

Mesenchymal stem cells are candidates for therapeutic strategies in periodontal repair due to their osteogenic potential. In this study, we identified epigenetic markers during osteogenic differentiation, taking advantage of the individual pattern of mesenchymal cells of the periodontal ligament with high (h-PDLCs) and low (l-PDLCs) osteogenic capacity. We found that the involvement of non-coding RNAs in the regulation of the RUNX2 gene is strongly associated with high osteogenic potential. Moreover, we evaluated miRs and genes that encode enzymes to process miRs and their biogenesis. Our data show the high expression of the XPO5 gene, and miRs 7 and 22 observed in the l-PDLCs might be involved in acquiring osteogenic potential, suppressing RUNX2 gene expression. Further, an inversely proportional correlation between lncRNAs (HOTAIR and HOTTIP) and RUNX2 gene expression was observed in both l- and h-PDLCs, and it was also related to the distinct osteogenic phenotypes. Thus, our results indicate the low expression of XPO5 in h-PDLC might be the limiting point for blocking the miRs biogenesis, allowing the high gene expression of RUNX2. In accordance, the low expression of miRs, HOTAIR, and HOTTIP could be a prerequisite for increased osteogenic potential in h-PDLCs. These results will help us to better understand the underlying mechanisms of osteogenesis, considering the heterogeneity in the osteogenic potential of PDLCs that might be related to a distinct transcriptional profile of lncRNAs and the biogenesis machinery.

Platelet microparticles load a repertory of miRNAs programmed to drive osteogenic phenotype

Autologous platelet-rich plasma accelerates bone healing by releasing biomolecules during their degranulation process, which are transported by vesicle-like structures called platelet microparticles (PMPs). However, the underlying mechanisms regulating the osteogenic differentiation by PMP-released miRs remain poorly understood and this prompted us to better address this issue. Thus, miRNAseq expression profiles (E-GEOD-76789) were downloaded from ArrayExpress database. GEO2R was performed to evaluate the differential expression, and mirnatap R package was used to find targets for differentially expressed miRNAs. An extend protein-protein (ePPI) network for osteogenic marker proteins was generated using String, and DAVID tools were used to perform gene ontology and KEGG pathway analysis from ePPI and miRNAs targets. Our data show that ePPI network was composed by 232 nodes and 2,175 edges, with a clustering coefficient of 0.546. MCODE was able to identify seven clusters contained in the ePPI network, and the two that presented a score above 10 were used in further analysis. Conversely, 15,944 different targets were found as down-expressed while 5,715 different targets were up-expressed. Among the downregulated 75 miRNAs, 70 have predicted targets present in the ePPI network, while the 21 upregulated miRNAs have 19 predicted targets in the ePPI network. Our study provides a registry of miRNAs that play a central role in regulating osteogenic phenotype, which might have potential therapeutic applications in bone regeneration and bone tissue engineering.

OsteoBLAST: Computational Routine of Global Molecular Analysis Applied to Biomaterials Development

For bone purposes, surface modifications are a common trend in biomaterials research aiming to reduce the time necessary for osteointegration, culminating in faster recovery of patients. In this scenario, analysis of intracellular signaling pathways have emerged as an important and reliable strategy to predict biological responses from in vitro approaches. We have combined global analysis of intracellular protein phosphorylation, systems biology and bioinformatics into an early biomaterial analysis routine called OsteoBLAST. We employed the routine as follows: the PamChip tyrosine kinase assay was applied to mesenchymal stem cells grown on three distinct titanium surfaces: machined, dual acid-etched and nanoHA. Then, OsteoBLAST was able to identify the most reliable spots to further obtain the differential kinome profile and finally to allow a comparison among the different surfaces. Thereafter, NetworKIN, STRING, and Cytoscape were used to build and analyze a supramolecular protein-protein interaction network, and DAVID tools identified biological signatures in the differential kinome for each surface.

LncRNA HOTAIR is a novel endothelial mechanosensitive gene

To better address whether the long noncoding RNAs (lncRNAs) HOTAIR and HOTTIP are mechanosensitive genes, they were investigated in differentially challenged endothelial cells with respect to a circuit of tensional forces, considering the performance of both arterial and venous endothelial cells. We subjected arterial- and venous-obtained endothelial cells to a circuit of tensional forces within a shear stress model in vitro. Real-time quantitative polymerase chain reaction analysis indicated that microRNA (miRNA)-related processing machinery is significantly required in shear stressed arterial endothelial cell metabolism, which orchestrates miRNA (small noncoding RNA) involvement, and their involvement suggests lncRNA involvement. Of lncRNAs HOTAIR and HOTTIP, only HOTAIR was mechanosensitive considering both arterial and venous endothelial cells, presenting a positive correlation between methylation signature and gene expression. Thereafter, using bioinformatics tools, lncRNA HOTAIR was predicted to modulate miRNA185, miRNA-21, and miRNA23b downregulation. We compared the values of gene expression with a Pearson's correlation test, and expected correlations were observed for miRNA185 (r = 0.8664), miRNA-21 (r = 0.8605), and miRNA23b (0.9128). Taken together, these findings clearly show that lncRNA HOTAIR responds to the shear stress and emerges as a novel mechanosensitive gene in endothelial cells. Altogether, this understanding of mechanosensitive transcriptional and posttranscriptional control involving HOTAIR can also lead to new forms of therapeutic intervention for various diseases, as well as new strategies for tissue engineering and regenerative medicine.

HOXA cluster gene expression during osteoblast differentiation involves epigenetic control

The HOXA gene cluster is generally recognized as a pivotal mediator of positional identity in the skeletal system, expression of different orthologues conferring alternative locational phenotype of the vertebrate bone. Strikingly, however, the molecular mechanisms that regulate orthologue-specific expression of different HOXA cluster members in gestating osteoblasts remain largely obscure, but in analogy to the processes observed in acute lymphatic leukemia it is assumed that alternative methylation of HOXA promoter regions drives position specific expression patterns. In an effort to understand HOXA cluster gene expression in osteogenesis we characterize both expression and the epigenetic landscape of the HOXA gene cluster during in vitro osteoblast formation from mesenchymal precursors. We observe that osteoblast formation per se provokes strong upregulation of HOXA gene cluster expression, in particular of midcluster genes, and paradoxal downregulation of HOXA7 and HOXA10. These differences in expression appear related to promoter methylation. LnRNAs HOTAIR and HOTTIP, known to modulate HOXA expression, are also regulated by their promoter methylation processing, but do not correlate with HOXA cluster expression profile. We thus conclude that HOXA expression is profoundly regulated during osteoblast differentiation through canonical methylation-dependent mechanisms but not through the flanking lnRNAs.

Differential inflammatory landscape stimulus during titanium surfaces obtained osteogenic phenotype

Molecular mechanism governing inflammatory scenario in response to titanium (Ti)-nanotexturing surfaces needs to be better addressed. Thus, we subjected pre-osteoblast to different Ti-texturing surfaces, as follows: machined (Mac), double acid-etching (DAE), and nanoscaled hydroxyapatite-blasted titanium surface (nHA), considering the cells chronically responding either directly (when the cells were cultured onto the surfaces) or indirectly (when the cells were challenged with the conditioned medium by the surfaces), up to 10 days. Our results showed that there is a dynamic requirement of inflammatory-related genes activation in response to nHA by up expressing IL1ß, IL6, IL10, and IL33 (direct condition) and IL6, IL10, IL18 (indirect condition). Importantly, our data show that there is inflammasome involvement, once NLRP3, ASC1, and CASP1 genes were also required. As we found a strong signal of IL10, an anti-inflammatory cytokine, we further investigated Sonic Hedgehog (Shh) signaling cascade. Surprisingly, Shh ligand and Smoothened (Smo) genes were up-modulated in response to nHA, while Patched (Ptc) was down-modulated. Finally, an interactome was built using bioinformatics reinforcing Shh signaling cascade on modulating IL10 transcripts by Src mediating this process and this prevalence of anti-inflammatory picture might explain the low profile of RANKL transcripts in response to nHA, compromising the osteoclastogenesis surrounding the implants. Taking our results into account, our data show that the inflammatory landscape promoted by nHA is strictly modulated by Shh signaling promoted anti-inflammatory pathways. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1597-1604, 2019.

Sonic hedgehog drives layered double hydroxides-induced acute inflammatory landscape

Although layered double hydroxides (LDH) have been listed as promising nanomaterials in human healthcare, very little has been achieved on osteoblast inflammatory signaling. Thus, osteoblasts were challenged with two LDHs (Mg₂Al-Cl and Zn₂Al-Cl, at 0.002 mg/mL) up to 24 h, establishing an acute inflammatory mechanism, as well as identifying whether Sonic hedgehog (Shh) signaling has an influence. Functional experiments were performed by previously treating (2 h) semiconfluent osteoblast cultures with cyclopamine molecule (cyc), a widely used Shh inhibitor. Considering inflammasome complex, the asc1 gene was significantly up-expressed in response to Zn₂Al-Cl - LDHs, as well as the nrlp3 gene. By treating the osteoblast with cyc, the asc1 gene presented an even higher profile. Our results found a down-modulation of major pro-inflammatory cytokines-related genes, when tnfα and il1ß were significantly down-modulated in response to LDHs. Conversely, anti-inflammatory cytokines were up-modulated considering the same experimental procedures. Except the il6, the other il13, il10, and tgfß genes were up modulated. Additionally, Shh signaling seems to modulate this repertory as both the il13 and il10 genes were significantly up-modulated when the Shh signaling was inhibited. Altogether, our results reveal for the first time the exigency of Shh-dependent anti-inflammatory signals in LDH-induced osteoblast responses.

The role of triiodothyronine hormone and mechanically-stressed endothelial cell paracrine signalling synergism in gene reprogramming during hBMSC-stimulated osteogenic phenotype in vitro

We therefore investigated whether there is synergism between triiodothyronine (T3) hormone and trophic molecules released from mechanically-stressed endothelial cells (EC-enriched medium) in osteogenic phenotype by mapping classical repertory of genes. Although there are studies reporting the efficiency of T3 hormone on bone cells, it is scarce considering their effect in conjunction with other physiologically active molecules, such as those released by the active endothelial cells. To address this issue, human bone marrow-derived mesenchymal stem cells (hBMSCs) were treated with EC-enriched medium subjected to shear-stress up to 72 h in vitro, in conjunction or not with T3 hormone. Although our results found an important synergism considering these parameters on modulating key bone-related gene markers, such as on the alkaline phosphatase (ALP) behavior (at both mRNA and protein content), contributing for osteoblast differentiation, important genes such as OSTERIX and RUNX2 were significantly down-expressed, while a over-expression of RANKL was found when the conjunction effect of T3 and endothelial paracrine signaling was considered. In addition, T3 hormone over expressed both OCT4 and NANOG genes in a DNA epigenetic-independent manner. However, we observed a dynamic reprogramming of DNMT1, DNMT3A, DNMT3B and TET1, important DNA-related epigenetic markers. Specifically, T3 hormone alone up-modulated TET2 transcripts profile. Complimentarily, expression of microRNA (miRs) processing-related genes also was modulated, as well as miR-10b, miR-22, miR-21, miR-143 and miR-145 transcriptional related profiles. Altogether, our results suggested a positive effect of mechanically-stressed endothelial cells-induced paracrine signaling on T3 hormone-obtaining osteogenic phenotype, contributing to understanding the paradoxal effect of T3 hormone on the bone physiology.

Zirconia stimulates ECM-remodeling as a prerequisite to pre-osteoblast adhesion/proliferation by possible interference with cellular anchorage

The biological response to zirconia (ZrO₂) is not completely understood, which prompted us to address its effect on pre-osteoblastic cells in both direct and indirect manner. Our results showed that zirconia triggers important intracellular signaling mainly by governing survival signals which leads to cell adhesion and proliferation by modulating signaling cascade responsible for dynamic cytoskeleton rearrangement, as observed by fluorescence microscopy. The phosphorylations of Focal Adhesion Kinase (FAK) and Rac1 decreased in response to ZrO₂ enriched medium. This corroborates the result of the crystal violet assay, which indicated a significant decrease of pre-osteoblast adhesion in responding to ZrO₂ enriched medium. However, we credit this decrease on pre-osteoblast adhesion to the need to govern intracellular repertory of intracellular pathways involved with cell cycle progression, because we found a significant up-phosphorylation of Mitogen-Activated Protein Kinase (MAPK)-p38 and Cyclin-dependent kinase 2 (CDK2), while p15 (a cell cycle suppressor) decreased. Importantly, Protein phosphatase 2 A (PP2A) activity decreased, guaranteeing the significant up-phosphorylation of MAPK -p38 in response to ZrO₂ enriched medium. Complementarily, there was a regulation of Matrix Metalloproteinases (MMPs) in response to Zirconia and this remodeling could affect cell phenotype by interfering on cell anchorage. Altogether, our results show a repertory of signaling molecules, which suggests that ECM remodel as a pre-requisite to pre-osteoblast phenotype by affecting their anchoring in responding to zirconia.

Dietary Salba (Salvia hispanica L) seed rich in α-linolenic acid improves adipose tissue dysfunction and the altered skeletal muscle glucose and lipid metabolism in dyslipidemic insulin-resistant rats

This work reports the effect of dietary Salba (chia) seed rich in n-3 α-linolenic acid on the morphological and metabolic aspects involved in adipose tissue dysfunction and the mechanisms underlying the impaired glucose and lipid metabolism in the skeletal muscle of rats fed a sucrose-rich diet (SRD). Rats were fed a SRD for 3 months. Thereafter, half the rats continued with SRD while in the other half, corn oil (CO) was replaced by chia seed for 3 months (SRD+chia). In control group, corn starch replaced sucrose. The replacement of CO by chia seed in the SRD reduced adipocyte hypertrophy, cell volume and size distribution, improved lipogenic enzyme activities, lipolysis and the anti-lipolytic action of insulin. In the skeletal muscle lipid storage, glucose phosphorylation and oxidation were normalized. Chia seed reversed the impaired insulin stimulated glycogen synthase activity, glycogen, glucose-6-phosphate and GLUT-4 protein levels as well as insulin resistance and dyslipidemia.

Dietary fish oil normalized glucose-stimulated insulin secretion in isolated pancreatic islets of dyslipemic rats through mechanisms involving glucose phosphorylation, peroxisome proliferator-activated receptor γ and uncoupling protein 2

This study evaluates some possible mechanisms behind the beneficial effects of dietary fish oil (FO) on β cell dysfunction in rats fed a sucrose-rich diet (SRD). Rats were fed a SRD for 6 months. Thereafter, half the rats received a SRD in which corn oil was partially replaced by FO up to 8 months. The other half continued consuming the SRD up to 8 months. A control group was fed a control diet throughout the experimental period. In isolated islets of SRD-fed rats dietary FO normalized the reduced glucose phosphorylation, the altered glucose oxidation, the triglyceride content, the increased protein mass levels of peroxisome proliferator-activated receptor γ (PPARγ) and uncoupling protein 2 without changes in GLUT2 and PPARα. These finding suggest that the changes mentioned above could be involved in the normalization of the altered glucose-stimulated insulin secretion pattern in this nutritional model of dyslipidemia and insulin resistance.

Programme of stepping down from twice daily proton pump inhibitor therapy for symptomatic gastro-oesophageal reflux disease associated with a formulary change at a VA medical center

BACKGROUND

In July 2001, our Veterans' Affairs hospital changed its formulary proton pump inhibitor (PPI) from lansoprazole to rabeprazole. All patients previously receiving lansoprazole 30 mg twice daily were switched to rabeprazole 20 mg once daily.

AIM

To determine if patients with gastro-oesophageal reflux disease (GERD), who were previously managed on lansoprazole 30 mg twice daily, could be maintained on rabeprazole 20 mg once daily.

PATIENTS AND METHODS

Four hundred and thirty-five patients had received lansoprazole 30 mg twice daily for at least 12 months before the formulary change. Medical records were reviewed for 12 months before and after the formulary change.

RESULTS

There were 432 men and three women with a mean age of 66.7 years (range: 38-91). Two hundred and twelve patients were excluded. Of the remaining 223, 111 (50%) were maintained successfully on rabeprazole 20 mg once daily. Twenty-three (10%) stayed off all acid suppression during follow-up. The number of endoscopies and clinic visits did not significantly change during the follow-up. Fifty-six percent who had erosive oesophagitis failed a dose taper compared with 31% of those with endoscopy-negative GERD (P<0.025).

CONCLUSIONS

Most patients receiving twice daily PPI therapy for GERD could be maintained on once daily PPI or no acid suppression for 12 months of follow-up. Dose reduction was more successful in those without erosive oesophagitis.

Programme of stepping down from twice daily proton pump inhibitor therapy for symptomatic gastro-oesophageal reflux disease associated with a formulary change at a VA medical center

BACKGROUND

In July 2001, our Veterans' Affairs hospital changed its formulary proton pump inhibitor (PPI) from lansoprazole to rabeprazole. All patients previously receiving lansoprazole 30 mg twice daily were switched to rabeprazole 20 mg once daily.

AIM

To determine if patients with gastro-oesophageal reflux disease (GERD), who were previously managed on lansoprazole 30 mg twice daily, could be maintained on rabeprazole 20 mg once daily.

PATIENTS AND METHODS

Four hundred and thirty-five patients had received lansoprazole 30 mg twice daily for at least 12 months before the formulary change. Medical records were reviewed for 12 months before and after the formulary change.

RESULTS

There were 432 men and three women with a mean age of 66.7 years (range: 38-91). Two hundred and twelve patients were excluded. Of the remaining 223, 111 (50%) were maintained successfully on rabeprazole 20 mg once daily. Twenty-three (10%) stayed off all acid suppression during follow-up. The number of endoscopies and clinic visits did not significantly change during the follow-up. Fifty-six percent who had erosive oesophagitis failed a dose taper compared with 31% of those with endoscopy-negative GERD (P<0.025).

CONCLUSIONS

Most patients receiving twice daily PPI therapy for GERD could be maintained on once daily PPI or no acid suppression for 12 months of follow-up. Dose reduction was more successful in those without erosive oesophagitis.

The role of inadequate health literacy skills in colorectal cancer screening

Colorectal cancer is ideally suited for early detection strategies that are likely to improve survival rates. Screening with either a fecal occult blood test (FOBT) or flexible sigmoidoscopy has been shown to identify precancerous polyps or cancers in early stages. However, persons with limited education and of lower socioeconomic status infrequently participate in screening programs in general and have very low rates of colorectal screening. Low literacy, which is common among persons with limited education and low income, may be an overlooked factor in understanding patients' decision making about colorectal cancer screening. This article provides information from focus groups about colorectal cancer screening, which we examine in the context of relevant literature on cancer screening and literacy. Using the health belief model, we examine the association between inadequate health literacy skills and low rates of colorectal cancer screening. The theoretical model also provides insights into strategies for improving knowledge, attitudes, and beliefs and screening rates for this challenging patient population.

Shear bond strength of one-bottle dentine bonding systems

The purpose of this in vitro study was to determine the shear bond strength (SBS) of composite resin to human, buccal dentine, using four one-bottle dentine bonding systems. Eighty recently extracted human molar teeth were embedded in metal rings by means of self-curing acrylic resin. The projecting buccal surfaces were ground wet on 600 grit silicone carbide paper in order to expose superficial dentine. The teeth were randomly divided into four groups (N=20): 1=Prime&tBond 2.1 (PB, Dentsply); 2=Scotchbond 1 (SB, 3M); 3=Optibond Solo (OS, Kerr) and 4=Syntac Single Component (SY, Vivadent). The dentine surfaces were etched, treated with one of the four dentine bonding systems, and cylinders of matching composites were then bonded to the surfaces by means of a silicone rubber split mould. All specimens were stored for 24 hours under water at 37 degrees C. The bonds were then stressed to failure with an Instron testing machine, operating at a crosshead speed of 0.5 mm/min. The data were statistically analysed (Kruskall-Wallis). The mean SBS (MPa) were: PB = 12.5 +/- 2.0; SB = 16.2 +/- 1.9; OS = 17.4 +/- 3.1 and SY= 8.1 +/- 1.9. There was a statistically significant difference (P = 0.0001) between the mean of SY and the other 3 groups, and also between PB and the other groups. There was no statistically significant difference (P = 0.244) between the SBS of OS and SB. SY demonstrated the lowest SBS.

Racial variation in the use of laparoscopic cholecystectomy in the Department of Veterans Affairs medical system

BACKGROUND

While studies have found racial differences in the rates of use of established invasive cardiac and cerebrovascular procedures, no study has evaluated racial variation in the rates of adoption of new surgical procedures. For patients undergoing laparoscopic cholecystectomy, the procedure represents a new and safe option that shortens the duration of postoperative hospitalization by almost one week. In this study, we evaluated whether, in the equal access Veterans Affairs (VA) medical system, the rate of adoption of this procedure and improvements in the duration of postoperative hospitalization differed between African-American and Caucasian patients.

STUDY DESIGN

Data were obtained from two sources-administrative claims files and prospectively compiled dinical data from medical records and patient interviews. In both data sets, frequency of use, length of stay, and outcomes for African-American and Caucasian patients undergoing minimally invasive and open gallbladder surgery were analyzed for the first four years of use of the procedure in the VA system (1992 to 1995).

RESULTS

Analyses based on claims files indicated that, after adjustment for potentially confounding variables, African-American patients who underwent cholecystectomy in VA medical centers were 25% less likely to undergo a minimally invasive cholecystectomy during the first 4 years of use of the new procedure (adjusted odds ratio, 0.74; 95% confidence interval, 0.66-0.83). Shortening of the average postoperative length of stay from 9 days or more in the prelaparoscopic era to less than 4.5 days for patients undergoing the laparoscopic procedure occurred in the first year for Caucasian patients, but did not occur until the fourth year for African-American patients (p<0.001). The overall difference in postoperative length of stay between African-American and Caucasian patients more than doubled from 1.7 days before introduction of laparoscopic cholecystectomy to 3.8 days in the fourth year. In comparison, analyses based on nurse-compiled clinical data indicated that, after adjustment for relevant clinical factors, racial variations in the rate of laparoscopic surgery were even larger (adjusted odds ratio for laparoscopic versus open cholecystectomy for African-American versus Caucasian veterans, 0.68; 95% confidence interval, 0.55-0.84).

CONCLUSIONS

Compared to Caucasian patients, African-American patients who underwent cholecystectomy in VA medical centers had an approximately 25% to 32% lower likelihood of undergoing minimally invasive cholecystectomy procedures. The differences in rates of adoption of laparoscopic surgery did not appear to be from more comorbid illnesses among African-American patients. African-American and Caucasian veterans may differ in their preference for new surgical procedures like laparoscopic cholecystectomy. Conversely, VA physicians may have been less likely to recommend laparoscopic cholecystectomies to African-American patients.

Diffusion of laparoscopic cholecystectomy in the Veterans Affairs health care system, 1991-1995

CONTEXT

Laparoscopic cholecystectomy has become the most widely used treatment for gallbladder disease. In HMO, Medicare, and fee-for-service settings, cholecystectomy rates increased 28% to 59% after introduction of laparoscopic cholecystectomy.

OBJECTIVE

To investigate the impact of the introduction of laparoscopic cholecystectomy on cholecystectomy rates and the operative mortality rate in Veterans Affairs (VA) hospitals.

DESIGN

Sequential cross-sectional study.

PATIENTS

All patients who underwent cholecystectomy from 1991 (before introduction of laparoscopic cholecystectomy) to 1995.

SETTING

133 VA hospitals.

OUTCOME MEASURES

Cholecystectomy rates, use of laparoscopic or open cholecystectomy, and operative mortality rate.

RESULTS

The annual number of cholecystectomies in the VA system increased by 10% from 1991 to 1995; the laparoscopic procedure accounted for 25% of the caseload in 1992 and 52% in 1995. Compared with patients having laparoscopic cholecystectomy, those having open cholecystectomy were more likely to be older, be male, and have acute cholecystitis or comorbid illnesses (P < 0.001). The operative mortality rate of open cholecystectomy increased by 46% during this 4-year period (from 2.4% to 3.4%) and was constant for laparoscopic cholecystectomy (about 0.5%). Given the increasing use of the laparoscopic procedure, however, the overall mortality rate of cholecystectomy during surgery decreased by 22% (from 2.4% to 1.8%). Despite increased use of the surgery, the absolute number of deaths decreased by 9%.

CONCLUSIONS

The introduction of laparoscopic cholecystectomy in the VA system was not accompanied by a large increase in cholecystectomy rates, as it was in fee-for-service, Medicare, and HMO systems. Because the rate of operations has changed only slightly, the total number of cholecystectomy-related deaths has decreased.

[The emergence of multiple antimicrobial resistance in Vibrio cholerae isolated from gastroenteritis patients in Ceará, Brazil]

Of 7058 Vibrio cholerae strains recovered from patients suspected of cholera in the State of Ceará between December 1991 and September 1993, two were resistant to antimicrobials (Ampicillin, erythromycin, trimethoprim-sulfamethoxazole, tetracycline) and to vibriostatic agent O/129 (2,4-diamino-6,7-diisopropylpteridine). From the bacteriological standpoint, one strain was identified as V. cholerae serogroup O:1, biotype El Tor, serovar Inaba, and another as V. cholerae serogroup O:22, biochemically classified as Heiberg type II. It was shown that only in the serogroup O:1 strain, multiple resistance was encoded by a plasmid transferrable by conjugation to Escherichia coli K12 and a sensitive strains of V. cholerae O1 and non-O1, with at a frequency between 8 x 10(-2) and 5 x 10(-6). The plasmid, with a molecular weight of 147 Kb, encoded both multiple resistance to antimicrobials and the vibriostatic compound (O/129), compatible with descriptions reported in other parts of world.

Relation between literacy, race, and stage of presentation among low-income patients with prostate cancer

PURPOSE

Diagnosis of advanced prostate cancer is a major health problem, especially among low-income men. Opportunities vary for early detection of prostate cancer for low-income black and white men because of financial, cultural, and social factors. In this study, we evaluated the association of poor literacy skills with higher rates of presentation of advanced stages of prostate cancer among low-income black and white men who received care in equal-access medical systems.

PATIENTS AND METHODS

Literacy and stage at diagnosis of prostate cancer were evaluated in 212 low-income men who received medical care in Shreveport, LA, and Chicago, IL. The patients' literacy was assessed with the Rapid Estimate of Adult Literacy in Medicine (REALM), an individually administered reading screening test designed specifically for use in the medical setting. Logistic regression models were used to evaluate predictors of metastatic disease at presentation as a function of patient age, race, literacy, and city.

RESULTS

Whereas black men were almost twice as likely to present with stage D prostate cancer (49.5% v 35.9%; P < .05), they were significantly more likely to have literacy levels less than sixth grade (52.3% v 8.7%; P < .001). However, after adjustment for differences in literacy, age, and city, race was not a significant predictor of advanced-stage prostate cancer.

CONCLUSION

Low literacy may be an overlooked but significant barrier to the diagnosis of early-stage prostate cancer among low-income white and black men. The development of culturally sensitive, low-literacy educational materials may improve patient awareness of prostate cancer and improve the frequency of diagnosis of early-stage cancer.

Intestinal helminthiasis and anaemia in youngsters from Matriz da Luz, district of São Lourenço da Mata, state of Pernambuco, Brazil

A group of youngsters (4-18 years old) in northeast Brazil was studied to establish the prevalence of anaemia and intestinal parasitism, as well as to analyze the correlation between them. Two criteria were used to determine the state of anaemia, the level of haemoglobin and the mean of corpuscular volume. The first was considered a single criterion and the second an associated criteria, used in an attempt to correlate anaemia with iron deficiency. The prevalence of intestinal parasitism was 93%, while the prevalence of anaemia was 43.1% and 16.1% according to the criteria employed (single or associated respectively). Anaemia was significantly associated with both sex and age. No significant statistical difference was observed when the association was made between each parasite and anaemia even with those more related to anaemia.

Resistance to 3-mercaptopropionic acid-induced seizures in hepatic encephalopathy

BACKGROUND/AIMS

To determine if a model of hepatic encephalopathy (HE) exhibits decreased sensitivity to the neuronal effects of a drug that induces seizures as a consequence of decreasing GABA-mediated inhibitory neurotransmission.

MATERIALS AND METHODS

3-Mercaptopropionic Acid (MPA) is an inhibitor of L-glutamate decarboxylase which catalyzes the synthesis of GABA from glutamate. MPA was administered, either by intraperitoneal or intracerebroventricular injection, into rats with stage III HE due to thioacetamide-induced fulminant hepatic failure and into normal control rats.

RESULTS

When MPA was administered by intraperitoneal injection, seizure-inducing doses were similar for rats with HE and control rats. However, when a constant dose of MPA (330 micrograms) was administered by intracerebroventricular injection, rats with HE took significantly longer to develop seizures than control rats (16.2 vs. 7.3 minutes; p < 0.0005).

CONCLUSIONS

In a model of HE: (i) There is increased resistance to the convulsive effects of MPA; and (ii) This phenomenon is apparent when MPA is given centrally, but not when it is given peripherally. Increased resistance to the development of a complication of reduced GABA-mediated neurotransmission induced by MPA in the model provides support for the hypothesis that HE is associated with increased GABA-mediated inhibitory neurotransmission.

Percentage cure of cement cured through various thicknesses of Cerec porcelain

Highly filled luting resins are recommended for bonding porcelain restorations to tooth structure. This in vitro investigation was undertaken to determine the degree of cure of a 82 per cent filled dual-curing luting resin, after it was cured through various thicknesses of Cerec Vita Mark II porcelain. Infrared, as well as micro-Raman spectroscopy were used to determine the degree of cure of the cement at different time intervals after mixing and exposure to the curing light. The results indicated that Cerec porcelain thicknesses greater than 3 mm adversely affected the degree of cure of the luting resin, even at 24 hours after mixing the cement.

The learning curve for laparoscopic colorectal surgery. Preliminary results from a prospective analysis of 1194 laparoscopic-assisted colectomies

BACKGROUND

Laparoscopic-assisted colectomy is an emerging technology for patients with cancer, polyps, inflammation, and other types of pathologic conditions. While previous studies have shown better outcomes for laparoscopic cholecystectomies when surgeons perform more procedures, there is no information on the relationship between surgeon volume and outcomes for laparoscopic-assisted colectomy.

OBJECTIVE

To evaluate whether better clinical outcomes are found for surgeons who perform higher numbers of laparoscopic-assisted colectomies and whether such a relationship, if it exists, applies to both intraoperative and postoperative outcomes.

DESIGN

Analysis of a data set of 1194 patients, operated on by 114 surgeons, from a prospective registry sponsored by the American Society of Colon and Rectal Surgeons, from May 1991 to October 1994.

MAIN OUTCOME MEASURES

Completion rate, intraoperative and postoperative complications, and length of hospital stay.

RESULTS

In 75% of cases, surgery was completed laparoscopically, with no difference between high-volume surgeons (> or = 40 cases) and low-volume surgeons. Length of stay (average, 6 days) did not vary according to surgeon volume. Postoperative complications occurred in 15% of cases, with a significantly lower rate for high-volume surgeons (10% vs 19%; P < .001). Intraoperative complications occurred in 5% of cases, with a nonsignificant trend toward a lower rate for high-volume surgeons (3.7% vs 6.3%). A multivariate regression analysis, adjusting for type of disease (cancer vs inflammation vs polyps) and for level of difficulty of the procedure (high vs low) showed that for high-volume surgeons there is a lower probability of both intraoperative complications (adjusted odds ratio, 0.56; 95% confidence interval, 0.32-0.97; P = .04) and postoperative complications (adjusted odds ratio, 0.48; 95% confidence interval, 0.34-0.68; P < .001).

CONCLUSIONS

There is a learning curve for laparoscopic-assisted colectomy with respect to intraoperative and postoperative outcomes. As with other laparoscopic procedures, surgeons who perform higher volumes of laparoscopic-assisted colectomy have lower rates of intraoperative and postoperative complications.

The effect of the depth of dentine on shear bond strength of adhesive resins

Dentine bonding agents require the use of a conditioner or primer which affects the adjacent dentine and/or smear layer. The appearance of superficial and deep dentine differs and this may affect the bond strength of adhesive systems. The purpose of this in vitro study was to investigate the bonding efficiency of two modern dentine bonding systems (DBS) i.e., Scotchbond Multi-Purpose (SBMP) and Imperva Bond (IB) when bonding composite resin, Z100 and Lite-Fil II, to firstly superficial and secondly to deep dentine. The bond strength values for SBMP to superficial and deep dentine were 24.7 MPa and 23.0 MPa respectively, and that of IB 19.3 MPa and 18.2 MPa. These differences were statistically significant for both products using the paired Student-t test (p < 0.05). Fractures sites were also examined in a SEM. For both products it was found that the samples which were bonded to the deep dentine showed lower bond strengths than those bonded to the superficial dentine.

Allergies to dental materials

Allergies related to dentistry generally constitute delayed hypersensitive reactions to specific dental materials. Although true allergic hypersensitivity to dental materials is rare, certain products have definite allergenic properties. Extensive reports in the literature substantiate that certain materials cause allergies in patients, who exhibit mucosal and skin symptoms. Currently, however, neither substantial data nor clinical experience unequivocally contraindicate the discontinuance of any of the materials, which include dental amalgam and nickel- and chromium-containing metals. The dentist forms a vital link in the team approach to the differential diagnosis of allergenic biomaterials that elicit symptoms in a patient, not only intraorally, but also on unrelated parts of the body.

Shear bond strength of a composite resin to differently silicoated base metal alloys

This study was undertaken to determine the shear bond strength of Charisma composite resin to both thermal and pyrogenic silicoated base metal alloys namely, Duracast MS, Rexillium V and Wironit extra-hard. The bonded specimens were subjected to three stress treatments prior to shear bond testing. The results indicated that both silicoating techniques significantly improved shear bond strengths to sandblasted alloys, whereas wet heat and thermocycling treatments reduced the bond strengths, except for pyrogenic silicoated Wironit. Thermocycling was more detrimental to thermal than to pyrogenic silicoated Rexillium nad Wironit specimens.

[Safety of ciprofibrate. Open study in a Portuguese population]

STUDY OBJECTIVE

To determine the safety of ciprofibrate in portuguese patients with dyslipidaemia.

DESIGN

Open-label study with 6-month therapy.

PARTICIPANTS

Sequential sample of 40 patients, 20 from each hospital, 37 patients (92.5%) completed the study.

METHODS

After at least one month of diet or washout period, all participants were given 100 mg/day of ciprofibrate, taken after the evening meal. Analysis and clinical examinations were performed at weeks (-4), (0), (+8), (+16) and (+24). Glycemia, uric acid, creatine kinase, creatinine and transaminases were determined.

MAIN RESULTS

Thirty-seven patients ended the study (92.5%), three abandoned because of gastrointestinal adverse effects, six other patients also complaint of gastrointestinal side effects. The creatinine and creatine kinase levels increased 9.7% and 19.2%, although kept in the normal range. There were no statistically significant changes in glycemia, uric acid and transaminases levels.

CONCLUSIONS

These results confirm the high safety of ciprofibrate in patients with dislipidaemia. The short term of this study does not allows taking conclusions about long term use of this drug.

Analysis of 8-hydroxy-2'-deoxyguanosine in rat urine and liver DNA by stable isotope dilution gas chromatography/mass spectrometry

A previously developed gas chromatographic/mass spectrometric method was applied to the measurement of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in rat liver DNA and in rat urine. For DNA samples, the method included: (i) fortification of samples with [15N]DNA (internal standard), (ii) enzymatic hydrolysis of DNA to deoxynucleosides, (iii) degradation of native nucleosides by treatment with trifluoroacetic acid and hydrazine, (iv) purification by C18 solid-phase extraction (SPE), (v) derivatization (acetylation followed by pentafluorobenzylation, Ac-PFB), and (vi) GC/MS analysis of the derivatives. For urine, the following methodology was used: (i) fortification of the samples with 8-18OHdG, (ii) prepurification by C18/OH SPE, (iii) derivatization, (iv) high-performance liquid chromatography purification of the Ac-PFB derivatives, and (v) GC/MS analysis. The precision of the method was demonstrated by carrying out replicate analysis of several urine and DNA samples: within-run and between-run variability was less than 5 and 8%, respectively. The analytical approaches were sufficiently sensitive to quantitate the urinary excretion of 8-OHdG (490 +/- 70 pmol/kg/24 h; sample size, 600 microliters urine) and to measure the level of 8-OHdG in liver DNA (20 8-OHdG/10(6) deoxynucleosides; sample size, 30 micrograms DNA) of rats not deliberately exposed to oxidative stress. Major advantages over previous methods are increased precision due to the use of proper isotopically labeled internal standards, and increased sensitivity due to the optimization of cleanup procedures. The simultaneous analysis of standards of three different oxidized nucleosides, namely 8-OHdG, thymidine glycol, and 5-hydroxy-methyl-2'-deoxyuridine, is shown.

[Effectiveness of ciprofibrate. Open study in a Portuguese population]

STUDY OBJECTIVE

To determine the efficacy of ciprofibrate in portuguese patients with hypercholesterolaemia, hypertriglyceridaemia and mixed hyperlipidaemia.

DESIGN

Open-label study with 6-month therapy.

SETTING

Out-patient clinics of two Central Hospitals.

PARTICIPANTS

Sequential sample of 40 patients 20 from each hospital. 37 patients (92.5%) completed the study; 14 had dyslipidaemia type IIa, 12 type IIb and 11 type IV.

METHODS

After at least one month of diet or washout period, all participants were given 100 mg/day of ciprofibrate, taken after the evening meal. Analysis and clinical examinations were performed at weeks (-4), (0), (+8), (+16) and (+24). Total (TC) and HDL (HDL-C) cholesterol, triglycerides (TG), apoproteins A-I, B100, and (a), and fibrinogen were determined. LDL-cholesterol (LDL-C) was calculated by means of the Friedewald formula, whenever TG < or = 400 mg/dl.

MAIN RESULTS

With ciprofibrate, in the whole population, TC, TG, LDL-C, apoB100, and TC/HDL-C ratio diminished, respectively 16.6%, 46.2%, 20.7%, 12.6% and 24.6%. HDL-C and apoA-I increased 10.4% and 4.2%. LDL-C was reduced by 29.5% (p = 0.0001) in type IIa patients, and increased 23% (not statistically significant) in type IV patients. The reduction of TG attained 57.4% in type IIb patients. One type IIb patient received 200 mg/day of the drug from week (+16) on. BMI, waist/hip ratio, hypertension, alcohol consumption and sex didn't affect ciprofibrate activity.

CONCLUSIONS

These results confirm the high efficacy of ciprofibrate in patients with hypercholesterolaemia, hypertriglyceridaemia and mixed hyperlipidaemia. In type IIa dyslipidaemia, the reduction of LDL-C was roughly equivalent to that of the less potent statins. In type IV dyslipidaemia LDL-C may increase moderately. The influence on apoprotein (a) and fibrinogen was positive but modest.

Shear bond strength of a composite resin after delayed bonding to a polymerised dentine bonding system

Polymerised adhesive may serve as a temporary sealant on prepared dentine surfaces and may be used as a precursor to the final bonding of a resin restoration. This procedure may, however, have an adverse effect on the strength of the final bond. This study was undertaken on 40 extracted human molar teeth to assess the effect of delayed bonding on the shear bond strength of a composite resin luted with a luting resin to abraded dentine treated with the Scotchbond Multi-Purpose (SMP) Bonding System (3M). No significant difference (p = 0.969) could be demonstrated between shear bond strengths achieved after immediate and delayed bonding to the polymerised Scotchbond Multi-Purpose adhesive.

[Hematogenic placentitis in chagasic mothers]

Foram estudadas 135 placentas de mães chagásicas que não transmitiram sua infecção ao feto. Em apenas uma destas placentas, encontrou-separasitismo associado a discreta vilosite, crônica e focal. Em outras 24 placentas, observou-se apenas vilosite, na ausência de parasitismo, determinando uma freqüência de 17,9% de vilosite de causa ignorada. Comparou-se esta freqüência com a de um grupo controle, composto de placentas de mães não-chagásicas. A diferença observada foi, estatisticamente, não significante.