Thrombocytopenia and Adverse Bleeding Events in Neonatal Lumbar Punctures in the Emergency Department.

OBJECTIVE: Lumbar punctures are performed as part of a routine evaluation of neonates with fever in the emergency department. Current recommendations regarding performing a lumbar puncture in the presence of thrombocytopenia exist for children with leukemia and other cancers; however, there are no such recommendations for the general neonatal population. This study assesses the frequency of thrombocytopenia and adverse bleeding events in neonates who undergo a lumbar puncture to determine whether a complete blood count, and specifically the platelet count, should be reviewed before performing the lumbar puncture. METHODS: This is a retrospective chart review of neonates 30 days or younger presenting to a single freestanding pediatric emergency department who received a lumbar puncture over the course of 11 years. The complete blood count was reviewed for thrombocytopenia, determined to be platelet count of less than 150,000/µL. The chart was reviewed for any documented adverse bleeding events associated with the lumbar puncture. RESULTS: A total population of 2145 was studied with 56 patients determined to be thrombocytopenic. Seven total bleeding events were identified: 1 in the thrombocytopenic group and 6 in the nonthrombocytopenic group. All bleeding events were deemed to be clinically significant, either resulting in prolonged hospital stay or required further workup and medical intervention. The percentage of clinically adverse bleeding events that were related to the lumbar puncture was 0 (0.0%; 95% confidence interval, 0.0%-6.4%) and 2 (0.1%; 95% confidence interval, 0.0%-0.3%) ( P = 1.0) in the thrombocytopenic and nonthrombocytopenic groups, respectively. CONCLUSIONS: Our results demonstrated a very low risk of bleeding events associated with lumbar punctures in neonates, with no increased risk in the thrombocytopenic group. As such, we conclude that waiting for the results of a complete blood count before performing the lumbar puncture in neonates without a known bleeding disorder is unnecessary.

Genome evolution of dengue virus serotype 1 under selection by Wolbachia pipientis in Aedes aegypti mosquitoes.

The introgression of antiviral strains of Wolbachia into Aedes aegypti mosquito populations is a public health intervention for the control of dengue. Plausibly, dengue virus (DENV) could evolve to bypass the antiviral effects of Wolbachia and undermine this approach. Here, we established a serial-passage system to investigate the evolution of DENV in Ae. aegypti mosquitoes infected with the wMel strain of Wolbachia. Using this system, we report on virus genetic outcomes after twenty passages of serotype 1 of DENV (DENV-1). An amino acid substitution, E203K, in the DENV-1 envelope protein was more frequently detected in the consensus sequence of virus populations passaged in wMel-infected Ae. aegypti than wild-type counterparts. Positive selection at residue 203 was reproducible; it occurred in passaged virus populations from independent DENV-1-infected patients and also in a second, independent experimental system. In wild-type mosquitoes and human cells, the 203K variant was rapidly replaced by the progenitor sequence. These findings provide proof of concept that wMel-associated selection of virus populations can occur in experimental conditions. Field-based studies are needed to explore whether wMel imparts selective pressure on DENV evolution in locations where wMel is established.

Complete sequences of six major histocompatibility complex haplotypes, including all the major MHC class II structures.

Accurate and comprehensive immunogenetic reference panels are key to the successful implementation of population-scale immunogenomics. The 5Mbp Major Histocompatibility Complex (MHC) is the most polymorphic region of the human genome and associated with multiple immune-mediated diseases, transplant matching and therapy responses. Analysis of MHC genetic variation is severely complicated by complex patterns of sequence variation, linkage disequilibrium and a lack of fully resolved MHC reference haplotypes, increasing the risk of spurious findings on analyzing this medically important region. Integrating Illumina, ultra-long Nanopore, and PacBio HiFi sequencing as well as bespoke bioinformatics, we completed five of the alternative MHC reference haplotypes of the current (GRCh38/hg38) build of the human reference genome and added one other. The six assembled MHC haplotypes encompass the DR1 and DR4 haplotype structures in addition to the previously completed DR2 and DR3, as well as six distinct classes of the structurally variable C4 region. Analysis of the assembled haplotypes showed that MHC class II sequence structures, including repeat element positions, are generally conserved within the DR haplotype supergroups, and that sequence diversity peaks in three regions around HLA-A, HLA-B+C, and the HLA class II genes. Demonstrating the potential for improved short-read analysis, the number of proper read pairs recruited to the MHC was found to be increased by 0.06%-0.49% in a 1000 Genomes Project read remapping experiment with seven diverse samples. Furthermore, the assembled haplotypes can serve as references for the community and provide the basis of a structurally accurate genotyping graph of the complete MHC region.

Medication Adherence in Vietnamese Patients with Cardiovascular and Endocrine-Metabolic Diseases.

(1) Background: COVID-19 has significantly affected the quality of life and the medication adherence of patients with chronic diseases. Attitudes towards the disease and preventive measures are the things that need to be considered for patient adherence to medication during the COVID-19 pandemic. We aimed to evaluate the rate and compare the medication adherence and the impact of the COVID-19 pandemic on medication adherence in Vietnamese patients with cardiovascular and endocrine−metabolic diseases. (2) Methods: A cross-sectional study was conducted on outpatients having chronic diseases such as cardiovascular or/and endocrine−metabolic diseases in some southern provinces in Vietnam. In each group of patients, medication adherence was measured and assessed with the General Medication Adherence Scale (GMAS), adjusted and validated in Vietnam. In addition, the study also investigated attitudes and practices to prevent COVID-19. (3) Results: Out of 1444 patients in our study, the level of adherence was recorded in 867 cases, accounting for 61.1%. The group of patients with only cardiovascular disease and patients with only endocrine−metabolic disease had relatively similar compliance rates of 62 and 61.1%, respectively. The leading cause of non-adherence to treatment in all three groups of patients in the study, as assessed by the GMAS, was non-adherence due to financial constraints. Our study showed that 71.6% of patients felt anxious when going to the hospital for a medical examination. However, only 53.7% identified the COVID-19 pandemic as obstructing treatment follow-up visits. The research results showed that the COVID-19 epidemic influences the patient's psychology with regard to re-examination and treatment adherence, with p coefficients of 0.003 and <0.001, respectively. (4) Conclusion: Medication adherence rates in two disease groups are close, and financial constraint is the fundamental reason for medication non-adherence. Regulatory agencies must take care of people's welfare to improve adherence in the epidemic context.

Medication Adherence of Vietnamese Outpatients with Chronic Diseases during the COVID-19 Pandemic.

The purpose of this study was to determine the medication adherence of outpatients with chronic diseases and the association between both patient attitudes and preventive practices regarding COVID-19 and their medication adherence. We performed a cross-sectional study in Vietnam. Medication adherence was determined using the translated and validated Vietnamese version of the General Medication Adherence Scale (GMAS). Patient attitudes and preventive practices regarding COVID-19 were measured using the 5K message of the Vietnam Ministry of Health (facemasks, disinfection, distance, no gatherings, health declarations). The associations between patient characteristics and medication adherence were determined by multivariable regression. The study included 1852 outpatients, and 57.6% of the patients adhered to their medications. Patients who recognized the pandemic's obstruction of medical follow-ups (OR = 1.771; 95%CI = 1.461−2.147; p < 0.001), who applied ≥2 preventive methods (OR = 1.422; 95%CI = 1.173−1.725; p = 0.001), who were employed (OR = 1.677; 95%CI = 1.251−2.248; p = 0.001), who were living in urban areas (OR = 1.336; 95%CI = 1.090−1.637; p = 0.005,) who possessed higher education levels (OR = 1.313; 95%CI = 1.059−1.629; p = 0.013), or who had ≤2 comorbidities (OR = 1.293; 95%CI = 1.044−1.600; p = 0.019) were more likely to adhere to their medications. The adherence percentage for outpatients with chronic diseases was quite low during the pandemic. Patients who did not recognize the COVID-19 pandemic's obstruction of medical follow-ups or who had poor preventive practices were less likely to adhere to medications. Healthcare providers should pay more attention to these groups to achieve desired treatment outcomes.

A chromosome scale tomato genome built from complementary PacBio and Nanopore sequences alone reveals extensive linkage drag during breeding.

The assembly and scaffolding of plant crop genomes facilitate the characterization of genetically diverse cultivated and wild germplasm. The cultivated tomato (Solanum lycopersicum) has been improved through the introgression of genetic material from related wild species, including resistance to pandemic strains of tobacco mosaic virus (TMV) from Solanum peruvianum. Here we applied PacBio HiFi and ONT Nanopore sequencing to develop independent, highly contiguous and complementary assemblies of an inbred TMV-resistant tomato variety. We show specific examples of how HiFi and ONT datasets can complement one another to improve assembly contiguity. We merged the HiFi and ONT assemblies to generate a long-read-only assembly where all 12 chromosomes were represented as 12 contiguous sequences (N50 = 68.5 Mbp). This chromosome scale assembly did not require scaffolding using an orthogonal data type. The merged assembly was validated by chromosome conformation capture data and is highly consistent with previous tomato genome assemblies that made use of genetic maps and Hi-C for scaffolding. Our long-read-only assembly reveals that a complex series of structural variants linked to the TMV resistance gene likely contributed to linkage drag of a 64.1-Mbp region of the S. peruvianum genome during tomato breeding. Through marker studies and ONT-based comprehensive haplotyping we show that this minimal introgression region is present in six cultivated tomato hybrid varieties developed in three commercial breeding programs. Our results suggest that complementary long read technologies can facilitate the rapid generation of near-complete genome sequences.

A novel aerogel from thermal power plant waste for thermal and acoustic insulation applications.

Massive quantities of fly ash are produced worldwide from thermal power plants, posing a serious environmental threat due to their storage and disposal problems. In this study, for the first time, fly ash is converted into an advanced and novel aerogel through a green and eco-friendly process. The developed aerogel has a low density of 0.10-0.19 g cm-3, a high porosity of up to 90%, a low thermal conductivity of 0.042-0.050 W/mK, and a good sound absorption coefficient (noise reduction coefficient [NRC] value of 0.20-0.30). It also shows a high compressive Young's modulus of up to 150 kPa. Therefore, the newly developed fly ash aerogel is a potential material for thermal and acoustic insulation applications, along with lightweight composites in automotive and aerospace applications.

Using NS1 Flavivirus Protein Microarray to Infer Past Infecting Dengue Virus Serotype and Number of Past Dengue Virus Infections in Vietnamese Individuals.

BACKGROUND: In recent years, researchers have had an increased focus on multiplex microarray assays, in which antibodies are measured against multiple related antigens, for use in seroepidemiological studies to infer past transmission. METHODS: We assess the performance of a flavivirus microarray assay for determining past dengue virus (DENV) infection history in a dengue-endemic setting, Vietnam. We tested the microarray on samples from 1 and 6 months postinfection from DENV-infected patients (infecting serotype was determined using reverse-transcription polymerase chain reaction during acute, past primary, and secondary infection assessed using plaque reduction neutralization tests 6 months postinfection). RESULTS: Binomial models developed to discriminate past primary from secondary infection using the protein microarray (PMA) titers had high area under the curve (0.90-0.97) and accuracy (0.84-0.86). Multinomial models developed to identify most recent past infecting serotype using PMA titers performed well in those with past primary infection (average test set: κ = 0.85, accuracy of 0.92) but not those with past secondary infection (κ = 0.24, accuracy of 0.45). CONCLUSIONS: Our results suggest that the microarray will be useful in seroepidemiological studies aimed at classifying the past infection history of individuals (past primary vs secondary and serotype of past primary infections) and thus inferring past transmission intensity of DENV in dengue-endemic settings. Future work to validate these models should be undertaken in different transmission settings and with samples later after infection.

Visual and Biochemical Evidence of Glycocalyx Disruption in Human Dengue Infection, and Association With Plasma Leakage Severity.

Background: Dengue is the most common arboviral infection globally; a minority of patients develop shock due to profound plasma leak through a disrupted endothelial barrier. Understanding of the pathophysiology underlying plasma leak is incomplete, but emerging evidence indicates a key role for degradation of the endothelial glycocalyx. Methods: We conducted an observational study in Vietnam to evaluate the sublingual microcirculation using sidestream darkfield imaging in (1) outpatients with confirmed dengue (2) patients hospitalized with dengue and (3) outpatients with other febrile illness (OFI). We estimated the glycocalyx degradation by measuring the perfused boundary region (PBR hf) and an overall microvascular health score (MVHS) with the software application GlycoCheckTM at enrolment, 48 h later and hospital discharge/defervescence. We measured plasma syndecan1 and endocan at the same time-points. We compared PBR hf, MVHS, syndecan1 and endocan, between (1) outpatients with confirmed dengue vs. OFI and (2) patients with dengue subdivided by clinical severity of plasma leak. Results: We included 75 patients with dengue (41 outpatients, 15 inpatients, 19 in intensive care) and 12 outpatients with OFI. Images from 45 patients were analyzed using GlycoCheckTM. There was no significant difference in PBR hf or MVHS between outpatients with dengue and OFI. Median plasma syndecan1 was not significantly different in outpatients with dengue vs. OFI, while median plasma endocan was significantly lower among patients with dengue vs. OFI during the critical phase. In patients with dengue, PBR hf was higher in patients with Grade 2 vs. Grade 0 plasma leakage during the critical phase (PBR hf 1.96 vs. 1.36 µm for Grade 2 vs. Grade 0 plasma leakage on days 4-6, respectively, p < 0.001). Median levels of plasma syndecan1 and endocan were higher in Grade 2 vs. Grade 0 plasma leakage, especially during the critical phase (Syndecan1 2,613.8 vs. 125.9 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4-6, respectively, p < 0.001, and endocan 3.21 vs. 0.16 ng/ml for Grade 2 vs. Grade 0 plasma leakage on days 4-6, respectively). Conclusions: We present the first human in vivo evidence of glycocalyx disruption in dengue, with worse visual glycocalyx damage and higher plasma degradation products associated with more severe plasma leak.

Dengue virus induces PCSK9 expression to alter antiviral responses and disease outcomes.

Dengue virus (DENV) infection requires cholesterol as a proviral factor, although statin treatment did not show antiviral efficacy in patients with dengue. Here, we show that DENV infection manipulated cholesterol metabolism in cells residing in low-oxygen microenvironments (hypoxia) such as in the liver, spleen, and lymph nodes. DENV infection induced expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), which reduces low-density lipoprotein receptor (LDLR) recycling and hence cholesterol uptake. We found that, whereas LDLR uptake would have distributed cholesterol throughout the various cell compartments, de novo cholesterol synthesis enriched this lipid in the endoplasmic reticulum (ER). With cholesterol enrichment in the ER, ER-resident STING and type I IFN (IFN) activation was repressed during DENV infection. Our in vitro findings were further supported by the detection of elevated plasma PCSK9 levels in patients with dengue with high viremia and increased severity of plasma leakage. Our findings therefore suggest that PCSK9 plays a hitherto unrecognized role in dengue pathogenesis and that PCSK9 inhibitors could be a suitable host-directed treatment for patients with dengue.

Multiple Wolbachia strains provide comparative levels of protection against dengue virus infection in Aedes aegypti.

The insect bacterium Wolbachia pipientis is being introgressed into Aedes aegypti populations as an intervention against the transmission of medically important arboviruses. Here we compare Ae. aegypti mosquitoes infected with wMelCS or wAlbB to the widely used wMel Wolbachia strain on an Australian nuclear genetic background for their susceptibility to infection by dengue virus (DENV) genotypes spanning all four serotypes. All Wolbachia-infected mosquitoes were more resistant to intrathoracic DENV challenge than their wildtype counterparts. Blocking of DENV replication was greatest by wMelCS. Conversely, wAlbB-infected mosquitoes were more susceptible to whole body infection than wMel and wMelCS. We extended these findings via mosquito oral feeding experiments, using viremic blood from 36 acute, hospitalised dengue cases in Vietnam, additionally including wMel and wildtype mosquitoes on a Vietnamese nuclear genetic background. As above, wAlbB was less effective at blocking DENV replication in the abdomen compared to wMel and wMelCS. The transmission potential of all Wolbachia-infected mosquito lines (measured by the presence/absence of infectious DENV in mosquito saliva) after 14 days, was significantly reduced compared to their wildtype counterparts, and lowest for wMelCS and wAlbB. These data support the use of wAlbB and wMelCS strains for introgression field trials and the biocontrol of DENV transmission. Furthermore, despite observing significant differences in transmission potential between wildtype mosquitoes from Australia and Vietnam, no difference was observed between wMel-infected mosquitoes from each background suggesting that Wolbachia may override any underlying variation in DENV transmission potential.

C-reactive protein as a potential biomarker for disease progression in dengue: a multi-country observational study.

BACKGROUND: Dengue infection can cause a wide spectrum of clinical outcomes. The severe clinical manifestations occur sufficiently late in the disease course, during day 4-6 of illness, to allow a window of opportunity for risk stratification. Markers of inflammation may be useful biomarkers. We investigated the value of C-reactive protein (CRP) measured early on illness days 1-3 to predict dengue disease outcome and the difference in CRP levels between dengue and other febrile illnesses (OFI). METHOD: We performed a nested case-control study using the clinical data and samples collected from the IDAMS-consortium multi-country study. This was a prospective multi-center observational study that enrolled almost 8000 participants presenting with a dengue-like illness to outpatient facilities in 8 countries across Asia and Latin America. Predefined severity definitions of severe and intermediate dengue were used as the primary outcomes. A total of 281 cases with severe/intermediate dengue were compared to 836 uncomplicated dengue patients as controls (ratio 1:3), and also 394 patients with OFI. RESULTS: In patients with confirmed dengue, median (interquartile range) of CRP level within the first 3 days was 30.2 mg/L (12.4-61.2 mg/L) (uncomplicated dengue, 28.6 (10.5-58.9); severe or intermediate dengue, 34.0 (17.4-71.8)). Higher CRP levels in the first 3 days of illness were associated with a higher risk of severe or intermediate outcome (OR 1.17, 95% CI 1.07-1.29), especially in children. Higher CRP levels, exceeding 30 mg/L, also associated with hospitalization (OR 1.37, 95% CI 1.14-1.64) and longer fever clearance time (HR 0.84, 95% CI 0.76-0.93), especially in adults. CRP levels in patients with dengue were higher than patients with potential viral infection but lower than patients with potential bacterial infection, resulting in a quadratic association between dengue diagnosis and CRP, with levels of approximately 30 mg/L associated with the highest risk of having dengue. CRP had a positive correlation with total white cell count and neutrophils and negative correlation with lymphocytes, but did not correlate with liver transaminases, albumin, or platelet nadir. CONCLUSIONS: In summary, CRP measured in the first 3 days of illness could be a useful biomarker for early dengue risk prediction and may assist differentiating dengue from other febrile illnesses.

Cellulose-based aerogels from sugarcane bagasse for oil spill-cleaning and heat insulation applications.

A promising and economic material for various applications, such as thermal insulation in construction building and oil clean-up in marine ecosystems, is successfully developed from the by-product of the sugarcane industry. Biodegradable sugarcane bagasse aerogels are produced using polyvinyl alcohol (PVA) binder, followed by a freeze-drying method. This environmental-friendly recycled aerogel has an ultra-low density ([0.016-0.112] g/cm3), a high porosity ([91.9-98.9]%), and a very low thermal conductivity ([0.031-0.042] W/mK). Its superhydrophobicity properties and its maximum oil absorption capacity (up to 25 g/g) are measured after coating aerogel samples with methyltrimethoxysilane (MTMS). The biodegradable aerogel has a Young's modulus of 88 K Pa and can be bent without breaking, demonstrating its high flexibility.

Fabrication and Properties of Hybrid Coffee-Cellulose Aerogels from Spent Coffee Grounds.

A fully biodegradable hybrid coffee-cotton aerogel has been successfully developed from spent coffee grounds, 100% cotton fiber and polyvinyl alcohol (PVA) flakes via environmental friendly processes. The cotton fibers in coffee aerogel help to maintain the structure and improve the overall properties of the new hybrid coffee-cotton aerogel. The results show that increasing the concentration of fibers, while keeping the concentration of spent coffee grounds constant, the sinking of coffee ground particles in solution and shrinking effect on the aerogels are minimized and the overall mechanical and oil absorption properties are improved. The developed hybrid aerogels possess high porosity of 92-95% and super-hydrophobicity with an average water contact angle of 139°. Oil absorption capacity achieves 16 g/g with 0.50 wt.% of cotton fibers inside the coffee aerogel. Their thermal conductivity is in the range of 0.037-0.045 W/mK and compressive Young's modulus achieves highest at 15.6 kPa. The properties of the hybrid aerogel indicate it as a potential material in several applications such as thermal insulation, oil absorption and filtration.

Applications of functionalized polyethylene terephthalate aerogels from plastic bottle waste.

Millions of tons of plastic are produced annually, but less than 10% are reported to be recycled. This work sets out to transform environmental plastic (polyethylene terephthalate - PET) waste into aerogels for high-value engineering applications, primarily to enhance the monetary incentive in recycling plastics. Coating techniques, using silicone ceramic (SCC) and (3-aminopropyl)triethoxysilane (APS, or APTES) solutions, are successfully devised to enhance the thermal stability and CO2 adsorption capability of rPET aerogel. The rPET/SCC aerogel exhibits improved thermal stability (up to 600 °C), enhanced thermal insulation (thermal conductivity Kavg = [31.8-34.9] mW/m·K), hydrophobic characteristics (up to 144.7° in contact angle) and enhanced rigidity (Young modulus Eavg = [4.5-124.8] kPa), while maintaining an ultra-low density (ρa = [14-62] g/cm3) and a high porosity (Φavg = [95.6-99.0]%). Moreover, the amine-functionalised rPET aerogel achieves a CO2 adsorption capacity of up to 0.44 mmol CO2/g, superior to several commercial physio-sorbents. These promising results obtained demonstrate that the rPET aerogel is a versatile material suitable for a wide variety of high-value engineering applications, including thermal insulation and direct CO2 capture applications.

Advanced Recycled Polyethylene Terephthalate Aerogels from Plastic Waste for Acoustic and Thermal Insulation Applications.

This work presents for the first time, a simple, practical and scalable approach to fabricating recycled polyethylene terephthalate (rPET) aerogels for thermal and acoustic insulation applications. The rPET aerogels were successfully developed from recycled PET fibers and polyvinyl alcohol (PVA) and glutaraldehyde (GA) cross-linkers using a freeze-drying process. The effects of various PET fiber concentrations (0.5, 1.0 and 2.0 by wt.%), fiber deniers (3D, 7D and 15D) and fiber lengths (32 mm and 64 mm) on the rPET aerogel structures and multi-properties were comprehensively investigated. The developed rPET aerogels showed a highly porous network structure (98.3⁻99.5%), ultra-low densities (0.007⁻0.026 g/cm³), hydrophobicity with water contact angles of 120.7⁻149.8°, and high elasticity with low compressive Young's modulus (1.16⁻2.87 kPa). They exhibited superior thermal insulation capability with low thermal conductivities of 0.035⁻0.038 W/m.K, which are highly competitive with recycled cellulose and silica-cellulose aerogels and better than mineral wool and polystyrene. The acoustic absorption results were also found to outperform a commercial acoustic foam absorber across a range of frequencies.

Endothelial Nitric Oxide Pathways in the Pathophysiology of Dengue: A Prospective Observational Study.

BACKGROUND: Dengue can cause increased vascular permeability that may lead to hypovolemic shock. Endothelial dysfunction may underlie this; however, the association of endothelial nitric oxide (NO) pathways with disease severity is unknown. METHODS: We performed a prospective observational study in 2 Vietnamese hospitals, assessing patients presenting early (<72 hours of fever) and patients hospitalized with warning signs or severe dengue. The reactive hyperemic index (RHI), which measures endothelium-dependent vasodilation and is a surrogate marker of endothelial function and NO bioavailability, was evaluated using peripheral artery tonometry (EndoPAT), and plasma levels of l-arginine, arginase-1, and asymmetric dimethylarginine were measured at serial time-points. The main outcome of interest was plasma leakage severity. RESULTS: Three hundred fourteen patients were enrolled; median age of the participants was 21(interquartile range, 13-30) years. No difference was found in the endothelial parameters between dengue and other febrile illness. Considering dengue patients, the RHI was significantly lower for patients with severe plasma leakage compared to those with no leakage (1.46 vs 2.00; P < .001), over acute time-points, apparent already in the early febrile phase (1.29 vs 1.75; P = .012). RHI correlated negatively with arginase-1 and positively with l-arginine (P = .001). CONCLUSIONS: Endothelial dysfunction/NO bioavailability is associated with worse plasma leakage, occurs early in dengue illness and correlates with hypoargininemia and high arginase-1 levels.

Functionalizing the γ-Position of α-Diazo-ß-ketoesters.

Although α-diazo-ß-ketoesters are synthetically versatile intermediates, methodology for introducing this functionality into complex molecules is still limited, most frequently involving a carboxylic acid precursor, which is then activated and transformed into a ß-ketoester, with the diazo group being subsequently added with a diazo transfer reagent. While introducing this highly functional moiety in a convergent one step process would be ideal, such an objective is limited by the relatively few studies which address functionalization of the α-diazo-ß-ketoester at the γ-position. In the present investigation, we evaluate strategies, both new and established, for functionalizing α-diazo-ß-ketoesters, particularly with regard to generating compounds prospectively useful in the synthesis of C1-substituted carbapenems. We report the first δ-aldehydo-α-diazo-ß-ketoester as well as a method for its oxidation to the corresponding methyl ester, and the formation of a new substituted pyrazole under basic conditions.

Association of Microvascular Function and Endothelial Biomarkers With Clinical Outcome in Dengue: An Observational Study.

BACKGROUND: The hallmark of severe dengue is increased microvascular permeability, but alterations in the microcirculation and their evolution over the course of dengue are unknown. METHODS: We conducted a prospective observational study to evaluate the sublingual microcirculation using side-stream dark-field imaging in patients presenting early (<72 hours after fever onset) and patients hospitalized with warning signs or severe dengue in Vietnam. Clinical findings, microvascular function, global hemodynamics assessed with echocardiography, and serological markers of endothelial activation were determined at 4 time points. RESULTS: A total of 165 patients were enrolled. No difference was found between the microcirculatory parameters comparing dengue with other febrile illnesses. The proportion of perfused vessels (PPV) and the mean flow index (MFI) were lower in patients with dengue with plasma than those without leakage (PPV, 88.1% vs 90.6% [P = .01]; MFI, 2.1 vs 2.4 [P = .007]), most markedly during the critical phase. PPV and MFI were correlated with the endothelial activation markers vascular cell adhesion molecule 1 (P < .001 for both) and angiopoietin 2 (P < .001 for both), negatively correlated. CONCLUSIONS: Modest microcirculatory alterations occur in dengue, are associated with plasma leakage, and are correlate with molecules of endothelial activation, angiopoietin 2 and vascular cell adhesion molecule 1.