Repopulation of decellularised porcine pulmonary valves in the right ventricular outflow tract of sheep: Role of macrophages.

The primary objective was to evaluate performance of low concentration SDS decellularised porcine pulmonary roots in the right ventricular outflow tract of juvenile sheep. Secondary objectives were to explore the cellular population of the roots over time. Animals were monitored by echocardiography and roots explanted at 1, 3, 6 (n = 4) and 12 months (n = 8) for gross analysis. Explanted roots were subject to histological, immunohistochemical and quantitative calcium analysis (n = 4 at 1, 3 and 12 months) and determination of material properties (n = 4; 12 months). Cryopreserved ovine pulmonary root allografts (n = 4) implanted for 12 months, and non-implanted cellular ovine roots were analysed for comparative purposes. Decellularised porcine pulmonary roots functioned well and were in very good condition with soft, thin and pliable leaflets. Morphometric analysis showed cellular population by 1 month. However, by 12 months the total number of cells was less than 50% of the total cells in non-implanted native ovine roots. Repopulation of the decellularised porcine tissues with stromal (α-SMA+; vimentin+) and progenitor cells (CD34+; CD271+) appeared to be orchestrated by macrophages (MAC 387+/ CD163low and CD163+/MAC 387-). The calcium content of the decellularised porcine pulmonary root tissues increased over the 12-month period but remained low (except suture points) at 401 ppm (wet weight) or below. The material properties of the decellularised porcine pulmonary root wall were unchanged compared to pre-implantation. There were some changes in the leaflets but importantly, the porcine tissues did not become stiffer. The decellularised porcine pulmonary roots showed good functional performance in vivo and were repopulated with ovine cells of the appropriate phenotype in a process orchestrated by M2 macrophages, highlighting the importance of these cells in the constructive tissue remodelling of cardiac root tissues.

Randomized pilot trial of praise text messages to improve medication adherence among adolescents and young adults with liver transplants.

BACKGROUND: AYA who have undergone liver transplantations often struggle to adhere to their post-transplant immunosuppressant medications, which can lead to serious health complications. The objective of this pilot study is to examine the acceptability and feasibility of a brief mobile health (mHealth) intervention and its impact on medication adherence among AYA liver transplant recipients. METHODS: Thirty-five AYAs (13-21 years old) were randomized to either (1) receive praise text messages whenever laboratory results indicated immunosuppressant medications within the expected range or (2) usual care. Motivation for adherence and adherence were assessed via self-report, and a MLVI was calculated based on values abstracted from the electronic health record. RESULTS: Multilevel, multivariate models showed significant associations between group assignment and some self-reported motivation and adherence outcomes but not MLVI. Specifically, AYA receiving the praise text messages were significantly more likely to report taking their prescribed doses (OR = 2.49, p = .03), taking their medicine according to the directions (OR = 2.39, p = .04), and being highly confident in taking their medication (OR = 2.46, p = .04), compared with the usual services group. Qualitative responses indicated praise texts were mostly helpful but could be improved. CONCLUSIONS: The results suggest texting patients about positive health indicators was acceptable and, with refinement, might promote AYA illness self-management.

Mycophenolate Mofetil Hepatotoxicity Associated With Mitochondrial Abnormality in Liver Transplant Recipients and Mice.

OBJECTIVES: Mycophenolate mofetil (MMF) is a widely used immunosuppressive agent. MMF hepatotoxicity has been reported in non-transplant and renal transplant patients with minimal histologic description. This is the first study describing detailed histology and ultrastructure of MMF hepatotoxicity. METHODS: Four liver-transplant recipients (Cases 1-4) were suspected to have MMF hepatotoxicity. Cases 1-3 (two females and one male; 4-17 years) had multiple biopsies for liver function test (LFT) abnormalities. Case 4 (female; 16 years) had a surveillance biopsy. Electron-microscopic examination (EM) was requested on Cases 1-3 for unexplained, persistent LFT elevation and histologic abnormalities despite therapy and Case 4 for unexplained histologic abnormalities despite a stable clinical course. To confirm the pathologic changes in the human allografts, livers from MMF-treated and untreated mice were also reviewed. RESULTS: While the allograft biopsies showed nonspecific histologic changes, EM revealed unequivocal mitochondrial abnormalities similar to those seen in primary and secondary mitochondrial disorders. In Cases 1 and 2, LFTs improved after stopping and reducing MMF, respectively. In Case 3, pre- and post-MMF treatment biopsies were performed and only the post-MMF biopsy demonstrated mitochondrial abnormalities. Mitochondrial abnormality in Case 4 was subclinical. The mouse study confirmed that MMF caused various stress changes in the mitochondria; number of mitochondria/cell (mean ± standard deviation; untreated group: 58.25 ±â€Š8.426; MMF-treated group: 76.37 ±â€Š18.66), number of lipid droplets/cell (untreated: 0.9691 ±â€Š1.150; MMF-treated: 3.649 ±â€Š4.143) and sizes of mitochondria (µm, untreated: 0.8550 ±â€Š0.3409; MMF-treated: 0.9598 ±â€Š0.5312) were significantly increased in hepatocytes in the MMF-treated mice compared with the untreated mice (P < 0.0001). CONCLUSIONS: Although MMF is safe for the majority of patients, MMF can cause mitochondrial stress, which may trigger more severe mitochondrial abnormalities in a small subset. MMF hepatotoxicity should be considered for MMF-treated patients with unexplained, persistent LFT abnormalities and nonspecific histologic findings. EM should be requested for these cases.

COVID-19 and Rheumatoid Arthritis share myeloid pathogenic and resolving pathways

BackgroundWe recently delineated the functional biology of pathogenic and inflammation resolving synovial tissue macrophage clusters in rheumatoid arthritis (RA). Whilst RA is not a viral respiratory syndrome, it represents a pro-inflammatory cytokine-driven chronic articular condition often accompanied by cardiovascular and lung pathologies. We hypothesised that functionally equivalent macrophage clusters in the lung might govern inflammation and resolution of COVID-19 pneumonitis. MethodsTo provide insight into the targetable functions of COVID-19 bronchoalveolar lavage (BALF) macrophage clusters, a comparative analysis of BALF macrophage single cell transcriptomics (scRNA-seq) with synovial tissue (ST) macrophage scRNA-seq and functional biology was performed. The function of shared BALF and ST MerTK inflammation-resolving pathway was confirmed with inhibitor in primary macrophage-synovial fibroblast co-cultures. Results. Distinct BALF FCNpos and FCNposSPP1pos macrophage clusters emerging in severe COVID-19 patients were closely related to ST CD48highS100A12pos and CD48posSPP1pos clusters driving synovitis in active RA. They shared transcriptomic profile and pathogenic mechanisms. Healthy lung resident alveolar FABP4pos macrophages shared a regulatory transcriptomic profile, including TAM (Tyro, Axl, MerTK) receptors pathway with synovial tissue TREM2pos macrophages that govern RA remission. This pathway was substantially altered in BALF macrophages of severe COVID-19. In vitro dexamethasone inhibited tissue inflammation via macrophages MerTK function. ConclusionPathogenesis and resolution of COVID-19 pneumonitis and RA synovitis might be driven by similar macrophage clusters and pathways. The MerTK-dependent anti-inflammatory mechanisms of dexamethasone, and the homeostatic function of TAM pathways that maintain RA in remission advocate the therapeutic MerTK agonism to ameliorate the cytokine storm and pneumonitis of severe COVID-19.

A single-nucleotide polymorphism in a Plasmodium berghei ApiAP2 transcription factor alters the development of host immunity.

The acquisition of malaria immunity is both remarkably slow and unpredictable. At present, we know little about the malaria parasite genes that influence the host's ability to mount a protective immune response. Here, we show that a single-nucleotide polymorphism (SNP) resulting in a single amino acid change (S to F) in an ApiAP2 transcription factor in the rodent malaria parasite Plasmodium berghei (Pb) NK65 allowed infected mice to mount a T helper cell 1 (TH1)-type immune response that controlled subsequent infections. As compared to PbNK65S, PbNK65F parasites differentially expressed 46 genes, most of which are predicted to play roles in immune evasion. PbNK65F infections resulted in an early interferon-γ response and a later expansion of germinal centers, resulting in high levels of infected red blood cell-specific TH1-type immunoglobulin G2b (IgG2b) and IgG2c antibodies. Thus, the Pb ApiAP2 transcription factor functions as a critical parasite virulence factor in malaria infections.

The phosphatidylethanolamine biosynthesis pathway provides a new target for cancer chemotherapy.

BACKGROUND & AIMS: Since human induced pluripotent stem cells (iPSCs) develop into hepatic organoids through stages that resemble human embryonic liver development, they can be used to study developmental processes and disease pathology. Therefore, we examined the early stages of hepatic organoid formation to identify key pathways affecting early liver development. METHODS: Single-cell RNA-sequencing and metabolomic analysis was performed on developing organoid cultures at the iPSC, hepatoblast (day 9) and mature organoid stage. The importance of the phosphatidylethanolamine biosynthesis pathway to early liver development was examined in developing organoid cultures using iPSC with a CRISPR-mediated gene knockout and an over the counter medication (meclizine) that inhibits the rate-limiting enzyme in this pathway. Meclizine's effect on the growth of a human hepatocarcinoma cell line in a xenotransplantation model and on the growth of acute myeloid leukemia cells in vitro was also examined. RESULTS: Transcriptomic and metabolomic analysis of organoid development indicated that the phosphatidylethanolamine biosynthesis pathway is essential for early liver development. Unexpectedly, early hepatoblasts were selectively sensitive to the cytotoxic effect of meclizine. We demonstrate that meclizine could be repurposed for use in a new synergistic combination therapy for primary liver cancer: a glycolysis inhibitor reprograms cancer cell metabolism to make it susceptible to the cytotoxic effect of meclizine. This combination inhibited the growth of a human liver carcinoma cell line in vitro and in a xenotransplantation model, without causing significant side effects. This drug combination was also highly active against acute myeloid leukemia cells. CONCLUSION: Our data indicate that phosphatidylethanolamine biosynthesis is a targetable pathway for cancer; meclizine may have clinical efficacy as a repurposed anti-cancer drug when used as part of a new combination therapy. LAY SUMMARY: The early stages of human liver development were modeled using human hepatic organoids. We identified a pathway that was essential for early liver development. Based upon this finding, a novel combination drug therapy was identified that could be used to treat primary liver cancer and possibly other types of cancer.

Exploring Plasmodium falciparum Var Gene Expression to Assess Host Selection Pressure on Parasites During Infancy.

In sub-Saharan Africa, children below 5 years bear the greatest burden of severe malaria because they lack naturally acquired immunity that develops following repeated exposure to infections by Plasmodium falciparum. Antibodies to the surface of P. falciparum infected erythrocytes (IE) play an important role in this immunity. In children under the age of 6 months, relative protection from severe malaria is observed and this is thought to be partly due to trans-placental acquired protective maternal antibodies. However, the protective effect of maternal antibodies has not been fully established, especially the role of antibodies to variant surface antigens (VSA) expressed on IE. Here, we assessed the immune pressure on parasites infecting infants using markers associated with the acquisition of naturally acquired immunity to surface antigens. We hypothesized that, if maternal antibodies to VSA imposed a selection pressure on parasites, then the expression of a relatively conserved subset of var genes called group A var genes in infants should change with waning maternal antibodies. To test this, we compared their expression in parasites from children between 0 and 12 months and above 12 months of age. The transcript quantity and the proportional expression of group A var subgroup, including those containing domain cassette 13, were positively associated with age during the first year of life, which contrasts with above 12 months. This was accompanied by a decline in infected erythrocyte surface antibodies and an increase in parasitemia during this period. The observed increase in group A var gene expression with age in the first year of life, when the maternal antibodies are waning and before acquisition of naturally acquired antibodies with repeated exposure, is consistent with the idea that maternally acquired antibodies impose a selection pressure on parasites that infect infants and may play a role in protecting these infants against severe malaria.

Severe Late-Onset Acute Cellular Rejection in a Pediatric Patient With Isolated Small Intestinal Transplant Rescued With Aggressive Immunosuppressive Approach: A Case Report.

Small intestinal transplantation is performed for patients with intestinal failure who failed other surgical and medical treatment. It carries notable risks, including, but not limited to, acute and chronic cellular rejection and graft malfunction. Late severe acute intestinal allograft rejection is associated with increased risk of morbidity and mortality and, in the majority of cases, ends with total enterectomy. It usually results from subtherapeutic immunosuppression or nonadherence to medical treatment. We present the case of a 20-year-old patient who underwent isolated small bowel transplant for total intestinal Hirschsprung disease at age 7. Due to medication nonadherence, she developed severe late-onset acute cellular rejection manifested by high, bloody ostomy output and weight loss. Ileoscopy showed complete loss of normal intestinal anatomic landmarks and ulcerated mucosa. Graft biopsies showed ulceration and granulation tissue with severe architectural distortion consistent with severe intestinal graft rejection. She initially received intravenous corticosteroids and increased tacrolimus dose without significant improvement. Her immunosuppression was escalated to include infliximab and finally antithymocyte globulin. Graft enterectomy was considered repeatedly; however, clinical improvement was noted eventually with evidence of histologic improvement and salvage of the graft. The aggressive antirejection treatment was complicated by development of post-transplant lymphoproliferative disorder that resolved with reducing immunosuppression. Her graft function is currently maintained on tacrolimus, oral prednisone, and a periodic infliximab infusion. We conclude that a prompt and aggressive immunosuppressive approach significantly increases the chance of rescuing small bowel transplant rejection.

An improved Plasmodium cynomolgi genome assembly reveals an unexpected methyltransferase gene expansion.

BACKGROUND: Plasmodium cynomolgi, a non-human primate malaria parasite species, has been an important model parasite since its discovery in 1907. Similarities in the biology of P. cynomolgi to the closely related, but less tractable, human malaria parasite P. vivax make it the model parasite of choice for liver biology and vaccine studies pertinent to P. vivax malaria. Molecular and genome-scale studies of P. cynomolgi have relied on the current reference genome sequence, which remains highly fragmented with 1,649 unassigned scaffolds and little representation of the subtelomeres.  Methods: Using long-read sequence data (Pacific Biosciences SMRT technology), we assembled and annotated a new reference genome sequence, PcyM, sourced from an Indian rhesus monkey. We compare the newly assembled genome sequence with those of several other Plasmodium species, including a re-annotated P. coatneyi assembly. RESULTS: The new PcyM genome assembly is of significantly higher quality than the existing reference, comprising only 56 pieces, no gaps and an improved average gene length. Detailed manual curation has ensured a comprehensive annotation of the genome with 6,632 genes, nearly 1,000 more than previously attributed to P. cynomolgi. The new assembly also has an improved representation of the subtelomeric regions, which account for nearly 40% of the sequence. Within the subtelomeres, we identified more than 1300 Plasmodium interspersed repeat ( pir) genes, as well as a striking expansion of 36 methyltransferase pseudogenes that originated from a single copy on chromosome 9. CONCLUSIONS: The manually curated PcyM reference genome sequence is an important new resource for the malaria research community. The high quality and contiguity of the data have enabled the discovery of a novel expansion of methyltransferase in the subtelomeres, and illustrates the new comparative genomics capabilities that are being unlocked by complete reference genomes.

Validation of Fall Risk Assessment Specific to the Inpatient Rehabilitation Facility Setting.

PURPOSE: To evaluate and compare the Morse Fall Scale (MFS) and the Casa Colina Fall Risk Assessment Scale (CCFRA) for identification of patients at risk for falling in an acute inpatient rehabilitation facility. The primary objective of this study was to perform a retrospective validation study of the CCFRAS, specifically for use in the inpatient rehabilitation facility (IRF) setting. DESIGN: Retrospective validation study. METHOD: The study was approved under expedited review by the local Institutional Review Board. Data were collected on all patients admitted to Cottage Rehabiliation Hospital (CRH), a 38-bed acute inpatient rehabilitation hospital, from March 2012 to August 2013. Patients were excluded from the study if they had a length of stay less than 3 days or age less than 18. The area under the receiver operating characteristic curve (AUC) and the diagnostic odds ratio were used to examine the differences between the MFS and CCFRAS. AUC between fall scales was compared using the DeLong Test. FINDINGS: There were 931 patients included in the study with 62 (6.7%) patient falls. The average age of the population was 68.8 with 503 males (51.2%). The AUC was 0.595 and 0.713 for the MFS and CCFRAS, respectively (0.006). The diagnostic odds ratio of the MFS was 2.0 and 3.6 for the CCFRAS using the recommended cutoffs of 45 for the MFS and 80 for the CCFRAS. CONCLUSION: The CCFRAS appears to be a better tool in detecting fallers vs. nonfallers specific to the IRF setting. CLINICAL RELEVANCE: The assessment and identification of patients at high risk for falling is important to implement specific precautions and care for these patients to reduce their risk of falling. The CCFRAS is more clinically relevant in identifying patients at high risk for falling in the IRF setting compared to other fall risk assessments. Implementation of this scale may lead to a reduction in fall rate and injuries from falls as it more appropriately identifies patients at high risk for falling.

Characterization and gene expression analysis of the cir multi-gene family of Plasmodium chabaudi chabaudi (AS).

BACKGROUND: The pir genes comprise the largest multi-gene family in Plasmodium, with members found in P. vivax, P. knowlesi and the rodent malaria species. Despite comprising up to 5% of the genome, little is known about the functions of the proteins encoded by pir genes. P. chabaudi causes chronic infection in mice, which may be due to antigenic variation. In this model, pir genes are called cirs and may be involved in this mechanism, allowing evasion of host immune responses. In order to fully understand the role(s) of CIR proteins during P. chabaudi infection, a detailed characterization of the cir gene family was required. RESULTS: The cir repertoire was annotated and a detailed bioinformatic characterization of the encoded CIR proteins was performed. Two major sub-families were identified, which have been named A and B. Members of each sub-family displayed different amino acid motifs, and were thus predicted to have undergone functional divergence. In addition, the expression of the entire cir repertoire was analyzed via RNA sequencing and microarray. Up to 40% of the cir gene repertoire was expressed in the parasite population during infection, and dominant cir transcripts could be identified. In addition, some differences were observed in the pattern of expression between the cir subgroups at the peak of P. chabaudi infection. Finally, specific cir genes were expressed at different time points during asexual blood stages. CONCLUSIONS: In conclusion, the large number of cir genes and their expression throughout the intraerythrocytic cycle of development indicates that CIR proteins are likely to be important for parasite survival. In particular, the detection of dominant cir transcripts at the peak of P. chabaudi infection supports the idea that CIR proteins are expressed, and could perform important functions in the biology of this parasite. Further application of the methodologies described here may allow the elucidation of CIR sub-family A and B protein functions, including their contribution to antigenic variation and immune evasion.

Genomic insights into the origin of parasitism in the emerging plant pathogen Bursaphelenchus xylophilus.

Bursaphelenchus xylophilus is the nematode responsible for a devastating epidemic of pine wilt disease in Asia and Europe, and represents a recent, independent origin of plant parasitism in nematodes, ecologically and taxonomically distinct from other nematodes for which genomic data is available. As well as being an important pathogen, the B. xylophilus genome thus provides a unique opportunity to study the evolution and mechanism of plant parasitism. Here, we present a high-quality draft genome sequence from an inbred line of B. xylophilus, and use this to investigate the biological basis of its complex ecology which combines fungal feeding, plant parasitic and insect-associated stages. We focus particularly on putative parasitism genes as well as those linked to other key biological processes and demonstrate that B. xylophilus is well endowed with RNA interference effectors, peptidergic neurotransmitters (including the first description of ins genes in a parasite) stress response and developmental genes and has a contracted set of chemosensory receptors. B. xylophilus has the largest number of digestive proteases known for any nematode and displays expanded families of lysosome pathway genes, ABC transporters and cytochrome P450 pathway genes. This expansion in digestive and detoxification proteins may reflect the unusual diversity in foods it exploits and environments it encounters during its life cycle. In addition, B. xylophilus possesses a unique complement of plant cell wall modifying proteins acquired by horizontal gene transfer, underscoring the impact of this process on the evolution of plant parasitism by nematodes. Together with the lack of proteins homologous to effectors from other plant parasitic nematodes, this confirms the distinctive molecular basis of plant parasitism in the Bursaphelenchus lineage. The genome sequence of B. xylophilus adds to the diversity of genomic data for nematodes, and will be an important resource in understanding the biology of this unusual parasite.

The prevalence of gastrointestinal problems in children across the United States with autism spectrum disorders from families with multiple affected members.

OBJECTIVE: : To perform a large registry-based study to determine the relative prevalence of gastrointestinal (GI) problems in children with an autism spectrum disorder (ASD) from families with multiple affected members compared with their unaffected sibling(s). METHODS: : In-home structured retrospective medical history interviews by parent recall were conducted by a pediatric neurologist. Our analysis sample included information about GI health of 589 subjects with idiopathic, familial ASD and 163 of their unaffected sibling controls registered with Autism Genetic Resource Exchange. Individuals with ASD were subgrouped into 3 autism severity groups (Full Autism, Almost Autism, and Spectrum) based on their Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Scale scores. RESULTS: : Parents reported significantly more GI problems in children with ASD (249/589; 42%) compared with their unaffected siblings (20/163; 12%) (p < .001). The 2 most common Gl problems in children with ASD were constipation (116/589; 20%) and chronic diarrhea (111/589; 19%). Conditional logistic regression analysis showed that having Full Autism (adjusted odds ratio [AOR] = 14.28, 95% confidence interval [CI]: 6.22-32.77) or Almost Autism (AOR = 5.16, 95% CI 2.02-13.21) was most highly associated with experiencing GI problems. Increased autism symptom severity was associated with higher odds of GI problems (AOR for trend = 2.63, 95% CI: 1.56-4.45). CONCLUSIONS: : Parents report significantly more GI problems in children with familial ASD, especially those with Full Autism, than in their unaffected children. Increased autism symptom severity is associated with increased odds of having GI problems.

Probiotics and prebiotics in pediatrics.

This clinical report reviews the currently known health benefits of probiotic and prebiotic products, including those added to commercially available infant formula and other food products for use in children. Probiotics are supplements or foods that contain viable microorganisms that cause alterations of the microflora of the host. Use of probiotics has been shown to be modestly effective in randomized clinical trials (RCTs) in (1) treating acute viral gastroenteritis in healthy children; and (2) preventing antibiotic-associated diarrhea in healthy children. There is some evidence that probiotics prevent necrotizing enterocolitis in very low birth weight infants (birth weight between 1000 and 1500 g), but more studies are needed. The results of RCTs in which probiotics were used to treat childhood Helicobacter pylori gastritis, irritable bowel syndrome, chronic ulcerative colitis, and infantile colic, as well as in preventing childhood atopy, although encouraging, are preliminary and require further confirmation. Probiotics have not been proven to be beneficial in treating or preventing human cancers or in treating children with Crohn disease. There are also safety concerns with the use of probiotics in infants and children who are immunocompromised, chronically debilitated, or seriously ill with indwelling medical devices. Prebiotics are supplements or foods that contain a nondigestible food ingredient that selectively stimulates the favorable growth and/or activity of indigenous probiotic bacteria. Human milk contains substantial quantities of prebiotics. There is a paucity of RCTs examining prebiotics in children, although there may be some long-term benefit of prebiotics for the prevention of atopic eczema and common infections in healthy infants. Confirmatory well-designed clinical research studies are necessary.

Leishmania (Viannia) braziliensis: influence of successive in vitro cultivation on the expression of promastigote proteinases.

Cysteine proteinases are an important virulence factor in Leishmania parasites. In this study we analyzed the cysteine proteinase expression of infective Leishmania (Viannia) braziliensis promastigotes, examining the expression induced by successive in vitro passages in culture. We observed that this parasite presents a decrease in its virulence over BALB/c macrophages, after successive passages in culture, but still they present proteinase activity, being capable of hydrolyzing the substrate pGlu-Phe-Leu-p Nitroanilide at pH 7.0. This proteinase activity also decreases in the course of the successive passages. Additionally, the decrease in the amount of CPB proteins following successive passages of promastigotes was verified by immunoblotting assays, using an anti-CPB antiserum. Real-time PCR assays were performed to assess the relative cpb expression when compared to a housekeeping gene in promastigote cDNA preparations from the first, fourth and seventh passages. Interestingly, the data indicate a relative increase in cpb gene transcripts as the promastigotes were maintained under in vitro culture: 2.2 times higher for fourth and 2.7 times higher for seventh passages when compared to the first passage. Thus, the information gathered here shows that the expression of cysteine proteinases is modified during in vitro cultivation of L. (V.) braziliensis promastigotes.

Direct growth of nanoporous Au and its application in electrochemical biosensing.

In this work, we have directly grown three-dimensional nanoporous Au networks onto a Ti substrate using the hydrothermal technique. This newly designed material with a large surface area was used as a supporting matrix for immobilizing a redox protein, hemoglobin (Hb), to develop a high-performance hydrogen peroxide biosensor. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray (EDX) spectroscopy were employed to characterize the morphology and composition of the fabricated nanoporous Au network. Cyclic voltammetry (CV) and amperometry were used to study and to optimize the performance of the fabricated electrochemical biosensor. Our CV studies show the direct electron transfer of Hb immobilized on the nanoporous Au network. In addition, amperometric H(2)O(2) sensing experiments revealed that the nanoporous Au-network based biosensor exhibits fast response, long linearity, a low detection limit, high stability and very good reproducibility. Under the optimized conditions, the linearity of the developed biosensor for the detection of H(2)O(2) spans from 5 x 10(-8) to 2 x 10(-4)M with a detection limit of 2 x 10(-8)M (based on S/N=3).

Two nonrecombining sympatric forms of the human malaria parasite Plasmodium ovale occur globally.

BACKGROUND: Malaria in humans is caused by apicomplexan parasites belonging to 5 species of the genus Plasmodium. Infections with Plasmodium ovale are widely distributed but rarely investigated, and the resulting burden of disease is not known. Dimorphism in defined genes has led to P. ovale parasites being divided into classic and variant types. We hypothesized that these dimorphs represent distinct parasite species. METHODS: Multilocus sequence analysis of 6 genetic characters was carried out among 55 isolates from 12 African and 3 Asia-Pacific countries. RESULTS: Each genetic character displayed complete dimorphism and segregated perfectly between the 2 types. Both types were identified in samples from Ghana, Nigeria, São Tomé, Sierra Leone, and Uganda and have been described previously in Myanmar. Splitting of the 2 lineages is estimated to have occurred between 1.0 and 3.5 million years ago in hominid hosts. CONCLUSIONS: We propose that P. ovale comprises 2 nonrecombining species that are sympatric in Africa and Asia. We speculate on possible scenarios that could have led to this speciation. Furthermore, the relatively high frequency of imported cases of symptomatic P. ovale infection in the United Kingdom suggests that the morbidity caused by ovale malaria has been underestimated.

ProteinWorldDB: querying radical pairwise alignments among protein sets from complete genomes.

MOTIVATION: Many analyses in modern biological research are based on comparisons between biological sequences, resulting in functional, evolutionary and structural inferences. When large numbers of sequences are compared, heuristics are often used resulting in a certain lack of accuracy. In order to improve and validate results of such comparisons, we have performed radical all-against-all comparisons of 4 million protein sequences belonging to the RefSeq database, using an implementation of the Smith-Waterman algorithm. This extremely intensive computational approach was made possible with the help of World Community Grid, through the Genome Comparison Project. The resulting database, ProteinWorldDB, which contains coordinates of pairwise protein alignments and their respective scores, is now made available. Users can download, compare and analyze the results, filtered by genomes, protein functions or clusters. ProteinWorldDB is integrated with annotations derived from Swiss-Prot, Pfam, KEGG, NCBI Taxonomy database and gene ontology. The database is a unique and valuable asset, representing a major effort to create a reliable and consistent dataset of cross-comparisons of the whole protein content encoded in hundreds of completely sequenced genomes using a rigorous dynamic programming approach. AVAILABILITY: The database can be accessed through http://proteinworlddb.org

Reducing the incidence of necrotizing enterocolitis in neonates with hypoplastic left heart syndrome with the introduction of an enteral feed protocol.

OBJECTIVE: Neonates with hypoplastic left heart syndrome are prone to gastrointestinal complications, including necrotizing enterocolitis, during initiation or advancement of enteral feeds. A feeding protocol was developed to standardize practice across a multidisciplinary team. The purpose of this study was to examine the impact of a standardized feeding protocol on the incidence of necrotizing enterocolitis and overall postoperative gastrointestinal morbidity. DESIGN: Retrospective case-control study. SETTING: Cardiothoracic intensive care unit of a tertiary care children's hospital. PATIENTS: Ninety-eight neonates with hypoplastic left heart syndrome admitted to the cardiothoracic intensive care unit after first-stage palliation. INTERVENTION: A retrospective chart review was performed. Two groups were analyzed: the preprotocol group (n = 52) was examined from January 2000 through December 31, 2001, and the postprotocol group (n = 46) from February 2002 through December 31, 2003. MEASUREMENTS AND MAIN RESULTS: The incidence of suspected or diagnosed necrotizing enterocolitis as defined by the modified Bell staging criteria was recorded. Data were also collected regarding postoperative day of enteral feed initiation, postoperative day full feeds attained, and postoperative hospital length of stay. Necrotizing enterocolitis was detected in 14 preprotocol (27%) and three postprotocol (6.5%) patients (p < .01). Enteral feeds were initiated later in the postprotocol group (7.5 vs. 5.5 days, p < .001), and number of days to full feeds was also later in the postprotocol group (7 vs. 4 days, p = .02). Hospital length of stay tended to be shorter in the postprotocol group (21.5 vs. 28 days, p = .25). CONCLUSION: Measures directed at reducing the incidence of necrotizing enterocolitis may reduce morbidity in neonates with hypoplastic left heart syndrome and reduce cost by decreasing hospital length of stay. A standardized feeding protocol instituted to address these problems likely contributed to reducing the incidence of necrotizing enterocolitis in this high-risk population.

Direct growth of novel alloyed PtAu nanodendrites.

A novel nanostructure of a PtAu catalyst, alloyed PtAu nanodendrites, has been synthesized via a reproducible single-step hydrothermal co-reduction of Pt and Au inorganic precursors and shows exceptionally high catalytic activity towards the electrooxidation of formic acid.