HOP1 and HAP2 are conserved components of the meiosis-related machinery required for successful mating in Leishmania

Whole genome analysis of Leishmania hybrids generated experimentally in sand flies supports a meiotic mechanism of genetic exchange, with Mendelian segregation of the nuclear genome. Here, we perform functional analyses through the generation of double drug-resistant hybrids in vitro and in vivo (during sand fly infections) to assess the importance of conserved meiosis-related genes in recombination and plasmogamy. We report that HOP1 and a HAP2-paralog (HAP2-2) are essential components of the Leishmania meiosis machinery and cell-to-cell fusion mechanism, respectively, since deletion of either gene in one or both parents significantly reduces or completely abrogates mating competence. These findings significantly advance our understanding of sexual reproduction in Leishmania, with likely relevance to other trypanosomatids, by formally demonstrating the involvement of a meiotic protein homolog and a distinct fusogen that mediates non-canonical, bilateral fusion in the hybridizing cells.

Examining the Relationship Between Extreme Temperature, Microclimate Indicators, and Gestational Diabetes Mellitus in Pregnant Women Living in Southern California

Few studies have assessed extreme temperatures' impact on gestational diabetes mellitus (GDM). We examined the relation between GDM risk with weekly exposure to extreme high and low temperatures during the first 24 weeks of gestation and assessed potential effect modification by microclimate indicators.

Methods

We utilized 2008-2018 data for pregnant women from Kaiser Permanente Southern California electronic health records. GDM screening occurred between 24 and 28 gestational weeks for most women using the Carpenter-Coustan criteria or the International Association of Diabetes and Pregnancy Study Groups criteria. Daily maximum, minimum, and mean temperature data were linked to participants' residential address. We utilized distributed lag models, which assessed the lag from the first to the corresponding week, with logistic regression models to examine the exposure-lag-response associations between the 12 weekly extreme temperature exposures and GDM risk. We used the relative risk due to interaction (RERI) to estimate the additive modification of microclimate indicators on the relation between extreme temperature and GDM risk.

Results

GDM risks increased with extreme low temperature during gestational weeks 20--24 and with extreme high temperature at weeks 11-16. Microclimate indicators modified the influence of extreme temperatures on GDM risk. For example, there were positive RERIs for high-temperature extremes and less greenness, and a negative RERI for low-temperature extremes and increased impervious surface percentage.

Discussion

Susceptibility windows to extreme temperatures during pregnancy were observed. Modifiable microclimate indicators were identified that may attenuate temperature exposures during these windows, which could in turn reduce the health burden from GDM.

Variation in Carotid Artery Stenosis Measurements Among Facilities Seeking Carotid Stenting Facility Accreditation

BACKGROUND

Based on the inclusion criteria of clinical trials, the degree of cervical carotid artery stenosis is often used as an indication for stent placement in the setting of extracranial carotid atherosclerotic disease. However, the rigor and consistency with which stenosis is measured outside of clinical trials are unclear. In an agreement study using a cross-sectional sample, we compared the percent stenosis as measured by real-world physician operators to that measured by independent expert reviewers.

METHODS

As part of the carotid stenting facility accreditation review, images were obtained from 68 cases of patients who underwent carotid stent placement. Data collected included demographics, stroke severity measures, and the documented degree of stenosis, termed operator-reported stenosis (ORS), by 34 operators from 14 clinical sites. The ORS was compared with reviewer-measured stenosis (RMS) as assessed by 5 clinicians experienced in treating carotid artery disease.

RESULTS

The median ORS was 90.0% (interquartile range, 80.0%-90.0%) versus a median RMS of 61.1% (interquartile range, 49.8%-73.6%), with a median difference of 21.8% (interquartile range, 13.7%-34.4%), P<0.001. The median difference in ORS and RMS for asymptomatic versus symptomatic patients was not statistically different (24.6% versus 19.6%; P=0.406). The median difference between ORS and RMS for facilities granted initial accreditation was smaller compared with facilities whose accreditation was delayed (17.9% versus 25.5%, P=0.035). The intraclass correlation between ORS and RMS was 0.16, indicating poor agreement. If RMS measurements were used, 72% of symptomatic patients and 10% of asymptomatic patients in the population examined would meet the Centers for Medicare and Medicaid Services criteria for stent placement.

CONCLUSIONS

Real-world operators tend to overestimate carotid artery stenosis compared with external expert reviewers. Measurements from facilities granted initial accreditation were closer to expert measurements than those from facilities whose accreditation was delayed. Since decisions regarding carotid revascularization are often based on percent stenosis, such measuring discrepancies likely lead to increased procedural utilization.

Identification of Postpartum Depression in Electronic Health Records: Validation in a Large Integrated Health Care System

BACKGROUND

The accuracy of electronic health records (EHRs) for identifying postpartum depression (PPD) is not well studied.

OBJECTIVE

This study aims to evaluate the accuracy of PPD reporting in EHRs and compare the quality of PPD data collected before and after the implementation of the International Classification of Diseases, Tenth Revision (ICD-10) coding in the health care system.

METHODS

Information on PPD was extracted from a random sample of 400 eligible Kaiser Permanente Southern California patients' EHRs. Clinical diagnosis codes and pharmacy records were abstracted for two time periods: January 1, 2012, through December 31, 2014 (International Classification of Diseases, Ninth Revision [ICD-9] period), and January 1, 2017, through December 31, 2019 (ICD-10 period). Manual chart reviews of clinical records for PPD were considered the gold standard and were compared with corresponding electronically coded diagnosis and pharmacy records using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Kappa statistic was calculated to measure agreement.

RESULTS

Overall agreement between the identification of depression using combined diagnosis codes and pharmacy records with that of medical record review was strong (κ=0.85, sensitivity 98.3%, specificity 83.3%, PPV 93.7%, NPV 95.0%). Using only diagnosis codes resulted in much lower sensitivity (65.4%) and NPV (50.5%) but good specificity (88.6%) and PPV (93.5%). Separately, examining agreement between chart review and electronic coding among diagnosis codes and pharmacy records showed sensitivity, specificity, and NPV higher with prescription use records than with clinical diagnosis coding for PPD, 96.5% versus 72.0%, 96.5% versus 65.0%, and 96.5% versus 65.0%, respectively. There was no notable difference in agreement between ICD-9 (overall κ=0.86) and ICD-10 (overall κ=0.83) coding periods.

CONCLUSIONS

PPD is not reliably captured in the clinical diagnosis coding of EHRs. The accuracy of PPD identification can be improved by supplementing clinical diagnosis with pharmacy use records. The completeness of PPD data remained unchanged after the implementation of the ICD-10 diagnosis coding.

Resection for Chronic Hepatic Abscess due to Infected Embolization Coils After Liver Injury

Liver injuries after blunt abdominal trauma are very common. Non-operative approaches to management are now the standard of care for many patients with up to and including grade V liver injuries. However, the long-term complications associated with coil embolization can be challenging to manage. We present the case of a 29-year-old male who presented with a chronic liver abscess which contained the coils following embolization of a grade IV liver injury and the subsequent transhepatic embolization of the pseudoaneurysm. In addition, the patient developed a fistula draining the abscess through the previously placed drain site that traversed the diaphragm. A multidisciplinary discussion was held between trauma surgery, hepatobiliary surgery, thoracic surgery, and interventional radiology to discuss the best treatment plan. The patient subsequently underwent liver resection, fistula tract resection, and diaphragm repair. This case presents a definitive management strategy for these complex patients.

Percutaneous Retrieval of Retained Gallstones

Laparoscopic cholecystectomy has become the gold standard for patients with gallbladder disease. However, spilled gallstones occur in up to 18% of laparoscopic cholecystectomies, which may result in retained gallstones. Though most do not cause issues, there may be abscess formation from 4 months to 10 years postoperatively. We present a 78-year-old patient who formed a subhepatic abscess 3 months postoperatively from his laparoscopic cholecystectomy secondary to a 1 cm retained gallstone. The abscess was percutaneously drained by interventional radiology (IR), and the stone was subsequently removed by IR using a percutaneous approach. Open and laparoscopic approaches have been previously described for abscess drainage and removal of gallstones. In this case, both the abscess and stone were drained and removed percutaneously by IR. Though this is an uncommon entity, percutaneous decompression can aid in preventing such patients from undergoing additional surgery.

Outcomes of Stroke Thrombectomy Performed by Interventional Radiologists vs Neurointerventional Physicians

PURPOSE

To test the hypothesis that interventional radiologists (IR) have outcomes for endovascular stroke thrombectomy (EVT) similar to Neurointerventional (NI) physicians and could be used to improve availability of thrombectomy.

MATERIALS AND METHODS

Eight hospitals providing EVT performed by IR and NI in the same institution submitted sequential retrospective data limited to the era of modern devices. Good clinical outcome (90 day modified Rankin score 0-2) and successful revascularization (modified Thrombolysis in Cerebral Infarction score > 2b) were compared between specialties, adjusted for treating hospital, patient age, stroke severity, Alberta Stroke Program Early CT Score (ASPECTS), time from symptom onset to door, and clot location. Propensity score matching was used to compare outcomes. A total of 1009 patients were entered (622 treated by IR and 387 treated by NI).

RESULTS

Median stroke onset to puncture was 245 vs 253 minutes (p=.49), technically successful revascularization was 81.8% vs 82.4% (p=.81), and good clinical outcome was 45.5% vs 50.1% (p=.16), respectively. After adjusting, physician specialty was not a significant predictor of good clinical outcome (odds ratio 1.028 [95% CI 0.760-1.390]; p=.86). After matching, mRS 0-2 was 47.7% for IR and 51.1% for NI (p=0.366).

CONCLUSION

There was no significant difference in successful revascularization and good clinical outcomes between IR and NI physicians. Outcomes by IR were similar to NI outcomes from previously published trials and registries. This may be useful to address coverage and access to stroke interventions.

Stress conditions promote Leishmania hybridization in vitro marked by expression of the ancestral gamete fusogen HAP2 as revealed by single-cell RNA-seq

Leishmania are protozoan parasites transmitted by the bite of sand fly vectors producing a wide spectrum of diseases in their mammalian hosts. These diverse clinical outcomes are directly associated with parasite strain and species diversity. Although Leishmania reproduction is mainly clonal, a cryptic sexual cycle capable of producing hybrid genotypes has been inferred from population genetic studies and directly demonstrated by laboratory crosses. Experimentally, mating competence has been largely confined to promastigotes developing in the sand fly midgut. The ability to hybridize culture promastigotes in vitro has been limited so far to low-efficiency crosses between two Leishmania tropica strains, L747 and MA37, that mate with high efficiency in flies. Here, we show that exposure of promastigote cultures to DNA damage stress produces a remarkably enhanced efficiency of in vitro hybridization of the L. tropica strains and extends to other species, including Leishmania donovani, Leishmania infantum, and Leishmania braziliensis, a capacity to generate intra- and interspecific hybrids. Whole-genome sequencing and total DNA content analyses indicate that the hybrids are in each case full genome, mostly tetraploid hybrids. Single-cell RNA sequencing of the L747 and MA37 parental lines highlights the transcriptome heterogeneity of culture promastigotes and reveals discrete clusters that emerge post-irradiation in which genes potentially involved in genetic exchange are expressed, including the ancestral gamete fusogen HAP2. By generating reporter constructs for HAP2, we could select for promastigotes that could either hybridize or not in vitro. Overall, this work reveals that there are specific populations involved in Leishmania hybridization associated with a discernible transcriptomic signature, and that stress facilitated in vitro hybridization can be a transformative approach to generate large numbers of hybrid genotypes between diverse species and strains.

Resistance Against Leishmania major Infection Depends on Microbiota-Guided Macrophage Activation

Innate immune cells present a dual role during leishmaniasis: they constitute the first line of host defense but are also the main host cells for the parasite. Response against the infection that results in the control of parasite growth and lesion healing depends on activation of macrophages into a classical activated phenotype. We report an essential role for the microbiota in driving macrophage and monocyte-derived macrophage activation towards a resistance phenotype against Leishmania major infection in mice. Both germ-free and dysbiotic mice showed a higher number of myeloid innate cells in lesions and increased number of infected cells, mainly dermal resident and inflammatory macrophages. Despite developing a Th1 immune response characterized by the same levels of IFN-γ production as the conventional mice, germ-free mice presented reduced numbers of iNOS+ macrophages at the peak of infection. Absence or disturbance of host microbiota impaired the capacity of bone marrow-derived macrophage to be activated for Leishmania killing in vitro, even when stimulated by Th1 cytokines. These cells presented reduced expression of inos mRNA, and diminished production of microbicidal molecules, such as ROS, while presenting a permissive activation status, characterized by increased expression of arginase I and il-10 mRNA and higher arginase activity. Colonization of germ-free mice with complete microbiota from conventional mice rescued their ability to control the infection. This study demonstrates the essential role of host microbiota on innate immune response against L. major infection, driving host macrophages to a resistance phenotype.

245Comparison of methods for classifying heterogeneity in gestational diabetes (GDM) and association with outcomes

Background

Clinical experience suggests that diverse clinical subtypes exist within the broader diagnosis of GDM. Analysis from a single centre recently outlined heterogeneity in GDM with respect to insulin secretion and sensitivity, defining four GDM subtypes: 1) GDMsecr (&lt;25th centile HOMA-β (Hb) for non-GDM); 2) GDMsens (&lt;25th centile Matsuda Index for non-GDM); 3) GDMmixed (both GDMsecr and GDMsens); 4) GDMND, no defect (neither GDMsecr and GDMsens). Classification using these subtypes is associated with adverse outcomes.

Methods

Following similar methodology, women with GDM were classified into four subtypes including comparison of Hb, insulinogenic index (II) and Stumvoll first-phase estimate (SV) for defining GDMsecr. Analyses compared neonatal outcomes with non-GDM women and between GDM groups using c2 tests and regression analyses adjusted for multiple confounders including maternal age, BMI and HAPO study centre.

Results

Hb, II and SV gave divergent results for GDMsecr, with only 19% concordance. In all analyses, GDMND (10% by Hb, 6% by II, 6% by SV) showed outcome frequencies similar to those of non-GDM women; groups 1-3 showed higher risks (p &lt; 0.01 vs non GDM). These results persisted in the fully adjusted model (aOR generally &gt;2.0).

Conclusions

Different clinical subtypes in GDM are associated with differing risks of adverse outcome.

Key messages

Determination of GDM subtype can assist in assessing GDM women at higher risk of adverse clinical outcome and help guide clinical practice.

In Vitro Generation of Leishmania Hybrids

Protozoan parasites in the genus Leishmania produce a broad spectrum of diseases in their human hosts. The strain and species-specific genes controlling these diverse clinical outcomes have remained poorly tractable using reverse genetics approaches. A cryptic sexual cycle involving a meiotic-like process has been described in Leishmania but is so far confined to parasites growing in the sand fly vector. Here, we describe the reproducible in vitro generation of hybrid clones using axenic culture forms of Leishmania tropica promastigotes. Analysis of SNPs marker inheritance and whole-genome sequencing data indicate that the progeny clones are full genomic hybrids. The demonstration that mating-competent forms arise in culture should facilitate experimental study of the mating biology of Leishmania and the generation of large numbers of recombinant parasites for positional cloning of important genes.

Xenodiagnosis to evaluate the infectiousness of humans to sandflies in an area endemic for visceral leishmaniasis in Bihar, India: a transmission-dynamics study

Background

Visceral leishmaniasis, also known on the Indian subcontinent as kala-azar, is a fatal form of leishmaniasis caused by the protozoan parasite Leishmania donovani and transmitted by the bites of the vector sandfly Phlebotomus argentipes. To achieve and sustain elimination of visceral leishmaniasis, the transmission potential of individuals exposed to L donovani from across the infection spectrum needs to be elucidated. The aim of this study was to evaluate the relative infectiousness to the sandfly vector of patients with visceral leishmaniasis or post-kala-azar dermal leishmaniasis, before and after treatment, and individuals with asymptomatic infection.

Methods

In this prospective xenodiagnosis study done in Muzaffarpur district of Bihar, India, we included patients with clinically confirmed active visceral leishmaniasis or post-kala-azar dermal leishmaniasis who presented to the Kala-Azar Medical Research Center. These participants received treatment for L donovani infection. We also included asymptomatic individuals identified through a serosurvey of 17 254 people living in 26 high-transmission clusters. Eligible participants were aged 12–64 years, were HIV negative, and had clinically or serologically confirmed L donovani infection. During xenodiagnosis, the forearms or lower legs of participants were exposed to 30–35 female P argentipes sandflies for 30 min. Blood-engorged flies were held in an environmental cabinet at 28°C and 85% humidity for 60–72 h, after which flies were dissected and evaluated for L donovani infection by microscopy and quantitative PCR (qPCR). The primary endpoint was the proportion of participants with visceral leishmaniasis or post-kala-azar dermal leishmaniasis, before and after treatment, as well as asymptomatic individuals, who were infectious to sandflies, with a participant considered infectious if promastigotes were observed in one or more individual flies by microscopy, or if one or more of the pools of flies tested positive by qPCR.

Findings

Between July 12, 2016, and March 19, 2019, we recruited 287 individuals, including 77 with active visceral leishmaniasis, 26 with post-kala-azar dermal leishmaniasis, and 184 with asymptomatic infection. Of the patients with active visceral leishmaniasis, 42 (55%) were deemed infectious to sandflies by microscopy and 60 (78%) by qPCR before treatment. No patient with visceral leishmaniasis was found to be infectious by microscopy at 30 days after treatment, although six (8%) were still positive by qPCR. Before treatment, 11 (42%) of 26 patients with post-kala-azar dermal leishmaniasis were deemed infectious to sandflies by microscopy and 23 (88%) by qPCR. Of 23 patients who were available for xenodiagnosis after treatment, one remained infectious to flies by qPCR on the pooled flies, but none remained positive by microscopy. None of the 184 asymptomatic participants were infectious to sandflies.

Interpretation

These findings confirm that patients with active visceral leishmaniasis and patients with post-kala-azar dermal leishmaniasis can transmit L donovani to the sandfly vector and suggest that early diagnosis and treatment could effectively remove these individuals as infection reservoirs. An important role for asymptomatic individuals in the maintenance of the transmission cycle is not supported by these data.

Funding

Bill & Melinda Gates Foundation.

The role of dermis resident macrophages and their interaction with neutrophils in the early establishment of Leishmania major infection transmitted by sand fly bite

There is substantial experimental evidence to indicate that Leishmania infections that are transmitted naturally by the bites of infected sand flies differ in fundamental ways from those initiated by needle inocula. We have used flow cytometry and intravital microscopy (IVM) to reveal the heterogeneity of sand fly transmission sites with respect to the subsets of phagocytes in the skin that harbor L. major within the first hours and days after infection. By flow cytometry analysis, dermis resident macrophages (TRMs) were on average the predominant infected cell type at 1 hr and 24 hr. By confocal IVM, the co-localization of L. major and neutrophils varied depending on the proximity of deposited parasites to the presumed site of vascular damage, defined by the highly localized swarming of neutrophils. Some of the dermal TRMs could be visualized acquiring their infections via transfer from or efferocytosis of parasitized neutrophils, providing direct evidence for the "Trojan Horse" model. The role of neutrophil engulfment by dermal TRMs and the involvement of the Tyro3/Axl/Mertk family of receptor tyrosine kinases in these interactions and in sustaining the anti-inflammatory program of dermal TRMs was supported by the effects observed in neutrophil depleted and in Axl-/-Mertk-/- mice. The Axl-/-Mertk-/- mice also displayed reduced parasite burdens but more severe pathology following L. major infection transmitted by sand fly bite.

Anti-Interleukin-10 Unleashes Transcriptional Response to Leishmanial Antigens in Visceral Leishmaniasis Patients

Visceral leishmaniasis (VL; Leishmania donovani) cases produce interferon-γ and tumor necrosis factor in response to soluble leishmanial antigen (SLA) in whole-blood assays. Using transcriptional profiling, we demonstrate the impact of interleukin-10 (IL-10), a cytokine implicated in VL, on this response. SLA stimulation identified 28 differentially expressed genes (DEGs), 17/28 in a single network with TNF as hub. SLA plus anti-IL-10 produced 454 DEGs, 292 in a single network with TNF, IFNG, NFKBIA, IL6, and IL1B as hubs in concert with a remarkable chemokine/cytokine storm. Our data demonstrate the singular effect of IL-10 as a potent immune modulator in VL.

M2-like, dermal macrophages are maintained via IL-4/CCL24 mediated cooperative interaction with eosinophils in cutaneous leishmaniasis

Tissue-resident macrophages (TRMs) maintain tissue homeostasis, but they can also provide a replicative niche for intracellular pathogens such as Leishmania. How dermal TRMs proliferate and maintain their M2 properties even in the strong TH1 environment of the L. major infected dermis is not clear. Here, we show that in infected mice lacking IL-4/IL-13 from eosinophils, dermal TRMs shifted to a pro-inflammatory state, their numbers declined, and disease was attenuated. Intravital microscopy revealed a rapid infiltration of eosinophils followed by their tight interaction with dermal TRMs. IL-4-stimulated dermal TRMs, in concert with IL-10, produced a large amount of CCL24 which functioned to amplify eosinophil influx and their interaction with dermal TRMs. An intraperitoneal helminth infection model also demonstrated a requirement for eosinophil-derived IL-4 to maintain tissue macrophages through a CCL24-mediated amplification loop. CCL24 secretion was confined to resident macrophages in other tissues, implicating eosinophil-TRM cooperative interactions in diverse inflammatory settings.

Abstract TP41: Similar Outcomes of Endovascular Ischemic Stroke Treatment Performed by Interventional Radiologists and Neuro Interventional Fellowship Trained Physicians

Introduction: Endovascular stroke treatment (EVT) may be provided by physicians with varying specialty training. It is possible that physicians without dedicated neurointerventional training will have outcomes inferior to physicians with such dedicated training.

Methods: Eight academic or community hospitals who provide EVT performed by interventional radiology (IR) and neurointerventional (NI) physicians (neurointerventional radiology, endovascular neurosurgery, or interventional neurology) in the same institution submitted sequential retrospective data limited to the era of modern clot extraction devices. Clinical outcome (modified Rankin score [mRS]) and successful revascularization (modified Thrombolysis in Cerebral Infarction [mTICI]) were compared between specialties, stratified for treating hospital, patient age, stroke severity, and clot location.

Results: A total of 1079 patients were entered (661 treated by IR and 418 treated by NI) and 90 day mRS was available for 1013 patients (632 treated by IR and 381 treated by NI). For IR vs NI, median stroke onset to puncture was 220 vs 217 minutes (p=0.25), median door to puncture was 67 vs 75 minutes (p=0.18), successful revascularization (mTICI 2b or higher) was 82% vs 84% (p=0.38), symptomatic intracranial hemorrhage was 7.8% vs 6.7% (p=0.58), emboli to new territory was 2.1% vs 4.5% (p=0.22), 90 day mRS 0-1 was 30% vs 35% (p=0.06), and 90 day mRS 0-2 was 43% vs 50% (p=0.03). There was no significant difference in outcomes for clot locations in the internal carotid, M-1, M-2, or basilar arteries. When outcomes were adjusted for hospital, patient age, and stroke severity, physician specialty was not a significant predictor of mRS 0-1 (p=0.687 odds ratio 0.940, confidence interval 0.694-1.272) or mRS 0-2 outcome (p=0.695 odds ratio 0.944, 95% confidence interval 0.707-1.260).

Conclusion: There was no significant difference in procedural or clinical outcome for EVT performed by IR vs NI physicians.

Snapshot of current carotid artery stenting practice and accreditation in the USA

Objective

The aim of this exploratory study was to compare the performance of carotid artery stenting (CAS) best practices between Intersocietal Accreditation Commission (IAC) accredited facilities and non-accredited facilities certified by the Centers for Medicare and Medicaid Services (CMS).

Methods

A random, anonymous survey was sent to CMS and IAC accredited facilities querying facility routine performance of 16 CAS procedure components found in published guidelines and utilised during clinical trials.

Results

There were 28 responses (response rate=17%). Significant differences were found between the CMS and the IAC facilities for four of 16 procedure measures: determination of modified Rankin Scale score prior to stenting (p=0.012, 95% CI 20% to 80%), accurate measurement of per cent stenosis using electronic callipers (p=0.005, 95% CI 24% to 84%), confirmation of anticoagulation with activated clotting time greater than 250 s prior to crossing the lesion (p=0.03, 95% CI 7% to 69%), and comparison of facility outcomes to accepted benchmarks for stroke and death (p=0.03, 95% CI 7% to 69%). Overall, IAC facilities performed all 16 procedures more frequently (97%) than CMS facilities (66%) (p<0.001, 95% CI 24% to 36%).

Conclusions

Although the sample size was small, the results demonstrated IAC accredited facilities are more likely to follow best practices, to use quantitative tools to select appropriate patients, and quantitively measure patient-centred clinical outcomes compared with CMS certified facilities. The findings raise the question as to the value of CMS certification versus IAC accreditation as a requirement for reimbursement.

Somatic hypermutation to counter a globally rare viral immunotype drove off-track antibodies in the CAP256-VRC26 HIV-1 V2-directed bNAb lineage

Previously we have described the V2-directed CAP256-VRC26 lineage that includes broadly neutralizing antibodies (bNAbs) that neutralize globally diverse strains of HIV. We also identified highly mutated "off-track" lineage members that share high sequence identity to broad members but lack breadth. Here, we defined the mutations that limit the breadth of these antibodies and the probability of their emergence. Mutants and chimeras between two pairs of closely related antibodies were generated: CAP256.04 and CAP256.25 (30% and 63% breadth, respectively) and CAP256.20 and CAP256.27 (2% and 59% breadth). Antibodies were tested against 14 heterologous HIV-1 viruses and select mutants to assess breadth and epitope specificity. A single R100rA mutation in the third heavy chain complementarity-determining region (CDRH3) introduced breadth into CAP256.04, but all three CAP256.25 heavy chain CDRs were required for potency. In contrast, in the CAP256.20/27 chimeras, replacing only the CDRH3 of CAP256.20 with that of CAP256.27 completely recapitulated breadth and potency, likely through the introduction of three charge-reducing mutations. In this individual, the mutations that limited the breadth of the off-track antibodies were predicted to occur with a higher probability than those in the naturally paired bNAbs, suggesting a low barrier to the evolution of the off-track phenotype. Mapping studies to determine the viral immunotypes (or epitope variants) that selected off-track antibodies indicated that unlike broader lineage members, CAP256.20 preferentially neutralized viruses containing 169Q. This suggests that this globally rare immunotype, which was common in donor CAP256, drove the off-track phenotype. These data show that affinity maturation to counter globally rare viral immunotypes can drive antibodies within a broad lineage along multiple pathways towards strain-specificity. Defining developmental pathways towards and away from breadth may facilitate the selection of immunogens that elicit bNAbs and minimize off-track antibodies.

Interleukin 2 is an Upstream Regulator of CD4+ T Cells From Visceral Leishmaniasis Patients With Therapeutic Potential

Control of visceral leishmaniasis (VL) caused by Leishmania donovani requires interferon-γ production by CD4+ T cells. In VL patients, antiparasitic CD4+ T-cell responses are ineffective for unknown reasons. In this study, we measured the expression of genes associated with various immune functions in these cells from VL patients and compared them to CD4+ T cells from the same patients after drug treatment and from endemic controls. We found reduced GATA3, RORC, and FOXP3 gene expression in CD4+ T cells of VL patients, associated with reduced Th2, Th17, and FOXP3+CD4+ T regulatory cell frequencies in VL patient blood. Interleukin 2 (IL-2) was an important upstream regulator of CD4+ T cells from VL patients, and functional studies demonstrated the therapeutic potential of IL-2 for improving antiparasitic immunity. Together, these results provide new insights into the characteristics of CD4+ T cells from VL patients that can be used to improve antiparasitic immune responses.

Whole genome sequencing of experimental hybrids supports meiosis-like sexual recombination in Leishmania

Hybrid genotypes have been repeatedly described among natural isolates of Leishmania, and the recovery of experimental hybrids from sand flies co-infected with different strains or species of Leishmania has formally demonstrated that members of the genus possess the machinery for genetic exchange. As neither gamete stages nor cell fusion events have been directly observed during parasite development in the vector, we have relied on a classical genetic analysis to determine if Leishmania has a true sexual cycle. Here, we used whole genome sequencing to follow the chromosomal inheritance patterns of experimental hybrids generated within and between different strains of L. major and L. infantum. We also generated and sequenced the first experimental hybrids in L. tropica. We found that in each case the parental somy and allele contributions matched the inheritance patterns expected under meiosis 97–99% of the time. The hybrids were equivalent to F1 progeny, heterozygous throughout most of the genome for the markers that were homozygous and different between the parents. Rare, non-Mendelian patterns of chromosomal inheritance were observed, including a gain or loss of somy, and loss of heterozygosity, that likely arose during meiosis or during mitotic divisions of the progeny clones in the fly or culture. While the interspecies hybrids appeared to be sterile, the intraspecies hybrids were able to produce backcross and outcross progeny. Analysis of 5 backcross and outcross progeny clones generated from an L. major F1 hybrid, as well as 17 progeny clones generated from backcrosses involving a natural hybrid of L. tropica, revealed genome wide patterns of recombination, demonstrating that classical crossing over occurs at meiosis, and allowed us to construct the first physical and genetic maps in Leishmania. Altogether, the findings provide strong evidence for meiosis-like sexual recombination in Leishmania, presenting clear opportunities for forward genetic analysis and positional cloning of important genes.

Leishmania promastigotes are able to undergo genetic exchange during their growth and development in the sand fly vector, however, it is still not known if they have a true sexual cycle involving meiosis. Here, we used whole genome sequencing to follow the chromosomal inheritance patterns of 44 experimental hybrids generated between different strains of L. major, L. infantum, and L. tropica. In almost every case the number of chromosomes and the allele contributions from each parent matched the inheritance patterns expected under meiosis. Rare instances of hybrid chromosomes that did not fit Mendelian expectations were observed, including gain or loss of somy, and loss of heterozygosity. Strong evidence for a meiotic-like process was also obtained from the genome wide patterns of recombination observed in the offspring generated from backcrosses involving an experimental or natural hybrid, consistent with crossing over occurring between homologous chromosomes during meiosis. The frequency and position of the recombination breakpoints observed on each chromosome allowed us to construct the first physical and genetic maps in Leishmania. The results demonstrate that forward genetic approaches are possible for positional cloning of important genes.

Teach students, Empower patients, Act collaboratively and Meet health goals: an early interprofessional clinical experience in transformed care

PURPOSE

Transformation of care teaching is often didactic and conceptual instead of practical and operational. Clinical environments, slow to transform, limit student exposure to key experiences that characterize transformed care. We describe the design and implementation of TEAM Clinic (Teach students, Empower patients, Act collaboratively, Meet health goals) - an early clinical learning experience to address this gap.

METHODS

The TEAM Clinic curriculum was based on a review of existing curricula and best practice recommendations for the transformation of care. Three key elements were selected as the focus for a low-volume, high-service clinic: patient centeredness, interprofessional collaboration and team-based care. Learners and medically and socially complex patients were recruited for voluntary participation and completed anonymous surveys about the experience during and afterward.

RESULTS

Nine first-year medical students, two first-year social work students and one pharmacy resident were integrated into the interprofessional team. Students were assigned roles adapted to their level and skill set; deliberate interprofessional pairing was assigned to broaden perspectives on scope and role of team members. Upon completion of this two-semester experience, 11 of the 12 learners returned surveys; all rated the experience as positive (strongly agree or agree) on the Authentic Clinical Interprofessional Experience - Evaluation of Interprofessional Site tool. Patient surveys indicated satisfaction with multiple aspects of the visit.

CONCLUSION

TEAM Clinic provided a practical example of transformation of care teaching in a not-yet-transformed environment. Logistical barriers included space, schedule and staffing. Facilitators included alignment with the goals of core curricula and faculty. Limitations included that this description of these curricula and this pilot come early in our longitudinal development of TEAM Clinic, constraining our ability to measure behavioral changes around interprofessional education, teamwork or patient centeredness. Next steps would examine the trajectory to these outcomes in the preclinical student group.

Pharmacomechanical Catheter-Directed Thrombolysis for Deep-Vein Thrombosis

BACKGROUND

The post-thrombotic syndrome frequently develops in patients with proximal deep-vein thrombosis despite treatment with anticoagulant therapy. Pharmacomechanical catheter-directed thrombolysis (hereafter "pharmacomechanical thrombolysis") rapidly removes thrombus and is hypothesized to reduce the risk of the post-thrombotic syndrome.

METHODS

We randomly assigned 692 patients with acute proximal deep-vein thrombosis to receive either anticoagulation alone (control group) or anticoagulation plus pharmacomechanical thrombolysis (catheter-mediated or device-mediated intrathrombus delivery of recombinant tissue plasminogen activator and thrombus aspiration or maceration, with or without stenting). The primary outcome was development of the post-thrombotic syndrome between 6 and 24 months of follow-up.

RESULTS

Between 6 and 24 months, there was no significant between-group difference in the percentage of patients with the post-thrombotic syndrome (47% in the pharmacomechanical-thrombolysis group and 48% in the control group; risk ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.11; P=0.56). Pharmacomechanical thrombolysis led to more major bleeding events within 10 days (1.7% vs. 0.3% of patients, P=0.049), but no significant difference in recurrent venous thromboembolism was seen over the 24-month follow-up period (12% in the pharmacomechanical-thrombolysis group and 8% in the control group, P=0.09). Moderate-to-severe post-thrombotic syndrome occurred in 18% of patients in the pharmacomechanical-thrombolysis group versus 24% of those in the control group (risk ratio, 0.73; 95% CI, 0.54 to 0.98; P=0.04). Severity scores for the post-thrombotic syndrome were lower in the pharmacomechanical-thrombolysis group than in the control group at 6, 12, 18, and 24 months of follow-up (P<0.01 for the comparison of the Villalta scores at each time point), but the improvement in quality of life from baseline to 24 months did not differ significantly between the treatment groups.

CONCLUSIONS

Among patients with acute proximal deep-vein thrombosis, the addition of pharmacomechanical catheter-directed thrombolysis to anticoagulation did not result in a lower risk of the post-thrombotic syndrome but did result in a higher risk of major bleeding. (Funded by the National Heart, Lung, and Blood Institute and others; ATTRACT ClinicalTrials.gov number, NCT00790335 .).

Establishing, Expanding, and Certifying a Closed Colony of Phlebotomus argentipes (Diptera: Psychodidae) for Xenodiagnostic Studies at the Kala Azar Medical Research Center, Muzaffarpur, Bihar, India

This pilot project was preliminary and essential to a larger effort to define the ability of certain human-subject groups across the infection spectrum to serve as reservoirs of Leishmania donovani infection to sand flies in areas of anthroponotic transmission such as in Bihar state, India. This is possible only via xenodiagnosis of well-defined subject groups using live vector sand flies. The objective was to establish at the Kala Azar Medical Research Center (KAMRC), Muzaffarpur, Bihar, India, a self-sustaining colony of Phlebotomus argentipes (Annandale & Brunneti), closed to infusion with wild-caught material and certified safe for human xenodiagnosis. Prior to this endeavor, no laboratory colony of this vector existed in India meeting the stringent biosafety requirements of this human-use study. From March through mid-December, 2015, over 68,000 sand flies were collected in human dwellings and cattle sheds using CDC-type light traps over 254 nights. Blood-fed and gravid P. argentipes females were selected and placed individually in isoline-rearing vials for oviposition, and >2,500 egg clutches were harvested. Progeny were reared according to standard methods, providing a continuous critical mass of F1 males and females to stimulate social feeding behavior. With construction of a large feeding cage and use of a custom-made rabbit restrainer, the desired level of blood-feeding on restrained rabbits was achieved to make the colony self-sustaining and expand it to working level. Once self-sustaining, the colony was closed to infusion with wild-caught material and certified free of specific human pathogens.

The midgut microbiota plays an essential role in sand fly vector competence for Leishmania major

For many arthropod vectors, the diverse bacteria and fungi that inhabit the gut can negatively impact pathogen colonization. Our attempts to exploit antibiotic treatment of colonized Phlebotomus duboscqi sand flies in order to improve their vector competency for Leishmania major resulted instead in flies that were refractory to the development of transmissible infections due to the inability of the parasite to survive and to colonize the anterior midgut with infective, metacyclic stage promastigotes. The parasite survival and development defect could be overcome by feeding the flies on different symbiont bacteria but not by feeding them on bacterial supernatants or replete medium. The inhibitory effect of the dysbiosis was moderated by lowering the concentration of sucrose (<30% w/v) used in the sugar feeds to maintain the colony. Exposure of promastigotes to 30% sucrose was lethal to the parasite in vitro. Confocal imaging revealed that the killing in vivo was confined to promastigotes that had migrated to the anterior plug region, corresponding to the highest concentrations of sucrose. The data suggest that sucrose utilization by the microbiota is essential to promote the appropriate osmotic conditions required for the survival of infective stage promastigotes in vivo.

Increased Transmissibility of Leishmania donovani From the Mammalian Host to Vector Sand Flies After Multiple Exposures to Sand Fly Bites

Background

Patients with active visceral leishmaniasis are important reservoirs in the anthroponotic transmission cycle of Leishmania donovani. The role of the blood or skin as a source of infection to sand flies remains unclear, and the possible effect of multiple exposures to fly bites on transmissibility has not been addressed.

Methods

L. donovani-infected hamsters underwent xenodiagnoses with Lutzomyia longipalpis on the same or different sites on the abdomen on 2 consecutive days or by artificial feeding on the skin or blood.

Results

The transmission of L. donovani from sick hamsters to flies was surprisingly low (mean, 24% of fed flies). New flies fed on the same site acquired significantly more infections (mean, 61%; P < .0001). By artificial feeding, flies could acquire infection from blood and skin. However, only artificial feeding on blood produced infections that correlated with the natural feeding (R = 0.792; P < .0001). Infections acquired from blood increased dramatically for blood obtained after exposure to bites, as did the parasitemia level and the number of monocytes in the circulation.

Conclusions

The bites of uninfected sand flies favor the transmissibility of L. donovani by infected hosts, owing to a systemic effect that exposure to bites has on the parasitemia. Patients with active visceral leishmaniasis are important reservoirs in the anthroponotic transmission cycle of Leishmania donovani. Using the hamster model of visceral disease, we demonstrate that prior exposure to bites of uninfected sand flies potentiates their ability to transmit infection to the vector.

Traumatic pulmonary artery pseudoaneurysm with concomitant pulmonary embolism

Traumatic pulmonary artery pseudoaneurysms are rare, with only 25 previously documented cases. We present a case of traumatic pulmonary artery pseudoaneurysm in a 27-year-old male with concomitant pulmonary embolism which presented eight days after injury. He was treated with coil embolization of the pseudoaneurysm along with inferior vena cava filter placement. This unique case of concomitant traumatic pulmonary artery pseudoaneurysm and pulmonary embolism made management challenging given the competing priorities.

IFN-gamma mediated inflammatory monocyte recruitment neutralizes iNOS-dependent parasite killing by expanding the permissive host cell reservoir during early Leishmania amazonensis infection

IFN-γ is a key factor in the elimination of intracellular parasites. However, during early L. amazonensis infection IFN-γ production does not correlate with a reduction in parasite growth and IFN-γ−/− mice do not have enhanced parasite loads. The reason why IFN-γ production does not reduce parasite loads during early L.a. infection is controversial. In order to investigate the role of IFN-γ during early L.a. infection we infected C57BL/6 Wt and IFN-γ−/− mice with 104 RFP+ parasites in the ear and followed disease for 6 wks. IFN-γ−/− mice showed equivalent lesion sizes and parasite numbers compared to Wt mice for the first 4 wks p.i., despite higher expression of the putative disease promoting factors IL-4 and arginase I. IFN-γ−/− mice had no CD11b+iNOS+ phagocytes while iNOS production was detected as early as 2 wks p.i. in Wt mice. Interestingly, Wt mice had higher numbers of inflammatory monocytes per ear during early infection. Inflammatory monocytes represented the majority of total infected cells and parasites within inflammatory monocytes cells were viable. Inflammatory monocytes were a small proportion of CD11b+iNOS+ cells in Wt mice and had significantly reduced levels of IFN-γR versus dendritic cells and macrophages. The enhanced host cell infiltrate observed in Wt mice may counteract the protective role of IFN-γ mediated iNOS expression. This could explain, in part, why IFN-γ production does not lead to a reduction in parasite load during early L. amazonesis infection. We propose IFN-γ plays a dual role, inducing both the expression of iNOS and parasite killing and the recruitment of inflammatory monocytes that support parasite replication during early infection.

Combined Immune Therapy for the Treatment of Visceral Leishmaniasis

Chronic disease caused by infections, cancer or autoimmunity can result in profound immune suppression. Immunoregulatory networks are established to prevent tissue damage caused by inflammation. Although these immune checkpoints preserve tissue function, they allow pathogens and tumors to persist, and even expand. Immune checkpoint blockade has recently been successfully employed to treat cancer. This strategy modulates immunoregulatory mechanisms to allow host immune cells to kill or control tumors. However, the utility of this approach for controlling established infections has not been extensively investigated. Here, we examined the potential of modulating glucocorticoid-induced TNF receptor-related protein (GITR) on T cells to improve anti-parasitic immunity in blood and spleen tissue from visceral leishmaniasis (VL) patients infected with Leishmania donovani. We found little effect on parasite growth or parasite-specific IFNγ production. However, this treatment reversed the improved anti-parasitic immunity achieved by IL-10 signaling blockade. Further investigations using an experimental VL model caused by infection of C57BL/6 mice with L. donovani revealed that this negative effect was prominent in the liver, dependent on parasite burden and associated with an accumulation of Th1 cells expressing high levels of KLRG-1. Nevertheless, combined anti-IL-10 and anti-GITR mAb treatment could improve anti-parasitic immunity when used with sub-optimal doses of anti-parasitic drug. However, additional studies with VL patient samples indicated that targeting GITR had no overall benefit over IL-10 signaling blockade alone at improving anti-parasitic immune responses, even with drug treatment cover. These findings identify several important factors that influence the effectiveness of immune modulation, including parasite burden, target tissue and the use of anti-parasitic drug. Critically, these results also highlight potential negative effects of combining different immune modulation strategies.

Meta-Analysis of Local Endovascular Therapy for Acute Ischemic Stroke

A meta-analysis was performed to assess randomized controlled trials comparing local endovascular therapy (with and without intravenous thrombolysis) versus standard care (intravenous thrombolysis alone when appropriate) for acute ischemic stroke. Local endovascular therapy showed a significant improvement in functional independence versus standard care (odds ratio, 1.779; 95% confidence interval, 1.262-2.507; P < .001). This benefit strengthened further on subgroup analyses of trials in which a majority of cases used stent retrievers, trials with intravenous thrombolysis use in both arms when appropriate, and trials that required preprocedural imaging of all patients. There were no significant differences between arms in terms of mortality, hemicraniectomy, intracranial hemorrhage, and cerebral edema rates (P > .05). In conclusion, in the treatment of acute ischemic stroke, local endovascular therapy leads to improved functional independence compared with standard care.

Temperature and time variations during osteotomies performed with different piezosurgical devices: an in vitro study

AIM

The aim of this experimental in vitro study was to evaluate the effects of the piezoelectric device in temperature and time variations in standardized osteotomies performed with similar tip inserts in bovine bone blocks.

METHODS

Two different piezosurgical devices were used the OE-F15(®) (Osada Inc., Los Angeles, California, USA) and the Surgybone(®) (Silfradent Inc., Sofia, Forli Cesena, Italy). Serrated inserts with similar geometry were coupled with each device (ST94 insert/test A and P0700 insert/test B). Osteotomies 10 mm long and 3 mm deep were performed in bone blocks resembling type II (dense) and type IV (soft) bone densities with and without irrigation. Thermal changes and time variations were recorded. The effects of bone density, irrigation, and device on temperature changes and time necessary to accomplish the osteotomies were analyzed.

RESULTS

Thermal analysis showed significant higher temperatures during piezosurgery osteotomies in hard bone without irrigation (P < 0.05). The type of piezosurgical device did not influence thermal variations (P > 0.05). Time analysis showed that the mean time values necessary to perform osteotomies were shorter in soft bone than in dense bone (P < 0.05).

CONCLUSIONS

Within the limitations of this in vitro study, it may be concluded that the temperature increases more in piezosurgery osteotomies in dense bone without irrigation; the time to perform the osteotomy with piezosurgery is shorter in soft bone compared to hard bone; and the piezosurgical device have a minimal influence in the temperature and time variations when a similar tip design is used during piezosurgery osteotomies.

Percutaneous debridement of posttraumatic infected major hepatic necrosis

Although percutaneous drainage of liver abscesses has long been the standard of care, percutaneous drainage of infected necrotic liver tissue is usually used only to stabilize a patient's condition in the setting of sepsis before surgical debridement is ultimately required, frequently in the form of a hepatic lobectomy. The present report describes three cases of curative percutaneous drainage and percutaneous debridement of posttraumatic infected major hepatic necrosis. Techniques used included catheter suction, lavage, and foreign body retrieval.

Leishmania specific CD4 T cells release IFNγ that limits parasite replication in patients with visceral leishmaniasis

Visceral leishmaniasis (VL) is associated with increased circulating levels of multiple pro-inflammatory cytokines and chemokines, including IL-12, IFNγ, and TNFα, and elevated expression of IFNγ mRNA in lesional tissue such as the spleen and bone marrow. However, an immunological feature of VL patients is that their peripheral blood mononuclear cells (PBMCs) typically fail to respond to stimulation with leishmanial antigen. Unexpectedly, it was recently shown that Leishmania specific IFNγ, can readily be detected when a whole blood stimulation assay (WBA) is used. We sought to define the conditions that permit whole blood cells to respond to antigen stimulation, and clarify the biological role of the IFNγ found to be released by cells from VL patients. CD4+ T cells were found to be crucial for and the main source of the IFNγ production in Leishmania stimulated whole blood (WB) cultures. Complement, antibodies and red blood cells present in whole blood do not play a significant role in the IFNγ response. The IFNγ production was reduced by blockade of human leukocyte antigen (HLA)-DR, indicating that the response to leishmanial antigens observed in WB of active VL patients is a classical HLA- T cell receptor (TCR) driven reaction. Most importantly, blockade of IFNγ in ex-vivo splenic aspirate cultures demonstrated that despite the progressive nature of their disease, the endogenous IFNγ produced in patients with active VL serves to limit parasite growth.

Our research aims to understand the immune failure underlying progression of human visceral leishmaniasis (VL). A key immunological feature of VL patients is that their peripheral blood mononuclear cells (PBMCs) do not respond to stimulation with leishmanial antigen. Surprisingly, when employing a whole blood assay we discovered significant levels of IFNγ in response to soluble Leishmania donovani antigen (WBA) in VL patients. We were interested to understand the relevance of the IFNγ to the anti-parasitic response. Animal models and in vitro studies have shown that IFNγ is a key effector cytokine required for control of the infection, however, the role of endogenous IFNγ in control of parasites in VL patients, has not been demonstrated. Our results show that CD4 cells were required for and were the source of Leishmania specific IFNγ in WBA of VL patients. Optimal IFNγ response required interaction with HLA-DR, supporting that VL is not due to an intrinsic Th1 response defect per se. The Leishmania driven IFNγ appears to limit parasite growth in patients with active VL, since blockade of IFNγ ex-vivo in splenic aspirate cultures enhanced parasite survival. This suggests that IFNγ may have been prematurely dismissed as an adjunct therapy in treatment of VL.

Asymptomatic Leishmania infection: a new challenge for Leishmania control

Visceral leishmaniasis (VL) is a serious parasitic disease, causing high morbidity and mortality in the developing world. The pathogenesis of VL is complex, and the clinical presentation ranges from asymptomatic infection to severe and fatal disease. Despite a wealth of research on the full-blown "clinical VL" syndrome, asymptomatic leishmania infections remain poorly understood. Asymptomatic infection could present a major challenge for control programs if its infectiousness is confirmed. In this viewpoint, we highlight the crucial knowledge gaps as well as the obstacles in research on asymptomatic leishmanial infection. Research in this area is essential for the development of more-effective VL control strategies.