James B Lok

BACKGROUND: Mosquitoes transmit filarial nematodes to both human and animal hosts, with worldwide health and economic consequences. Transmission to a vertebrate host requires that ingested microfilariae develop into infective third-stage larvae capable of emerging from the mosquito proboscis onto the skin of the host during blood-feeding. Determining the number of microfilariae that successfully develop to infective third-stage larvae in the mosquito host is key to understanding parasite transmission potential and to developing new strategies to block these worms in their vector...

Chikungunya virus (CHIKV) is an emerging viral pathogen that causes both acute and chronic debilitating arthritis. Here, we describe the functional and structural basis as to how two anti-CHIKV monoclonal antibodies, CHK-124 and CHK-263, potently inhibit CHIKV infection in vitro and in vivo. Our in vitro studies show that CHK-124 and CHK-263 block CHIKV at multiple stages of viral infection. CHK-124 aggregates virus particles and blocks attachment. Also, due to antibody-induced virus aggregation, fusion with endosomes and egress are inhibited...

Autophagy is postulated to be required by cancer cells to survive periods of metabolic and/or hypoxic stress. ATG7 is the E1 enzyme that is required for activation of Ubl conjugation pathways involved in autophagosome formation. This article describes the design and optimization of pyrazolopyrimidine sulfamate compounds as potent and selective inhibitors of ATG7. Cellular levels of the autophagy markers, LC3B and NBR1, are regulated following treatment with these compounds.

The cytochrome P450 superfamily of heme monooxygenases catalyze important chemical reactions across nature. The changes in the optical spectra of these enzymes, induced by the addition of substrates or inhibitors, are critical for assessing how these molecules bind to the P450, enhancing or inhibiting the catalytic cycle. Here we use the bacterial CYP199A4 en-zyme (Uniprot ID; Q2IUO2), from Rhodopseudomonas palustris HaA2, and a range of substituted benzoic acids to investi-gate different binding modes. 4-Methoxybenzoic acid elicits an archetypal type I spectral response due to a 95% switch from the low- to high-spin state with concomitant dissociation of the sixth aqua ligand...

Mosquito-borne helminth infections are responsible for a significant worldwide disease burden in both humans and animals. Accordingly, development of novel strategies to reduce disease transmission by targeting these pathogens in the vector are of paramount importance. We found that a strain of Aedes aegypti that is refractory to infection by Dirofilaria immitis , the agent of canine heartworm disease, mounts a stronger immune response during infection than does a susceptible strain. Moreover, activation of the Toll immune signaling pathway in the susceptible strain arrests larval development of the parasite, thereby decreasing the number of transmission-stage larvae...

Purpose of Review: This paper constitutes an update of recent studies on the general biology, molecular genetics, and cellular biology of Strongyloides spp. and related parasitic nematodes. Recent Findings: Increasingly, human strongyloidiasis is considered the most neglected of neglected tropical diseases. Despite this, the last 5 years has seen remarkable advances in the molecular biology of Strongyloides spp. Genome sequences for S. stercoralis, S. ratti, S. venezuelensis , S...

OBJECTIVE: We aim to non-invasively facilitate activation of spared neural circuits after cervical spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS). We developed and tested a novel configuration for cervical transcutaneous spinal stimulation (cTSS). METHODS: cTSS was delivered via electrodes placed over the midline at ~T2-T4 levels posteriorly and ~C4-C5 levels anteriorly. Electromyographic responses were measured in arm and hand muscles across a range of stimulus intensities...

Hepatic encephalopathy (HE) is a devastating complication of cirrhosis. Data are limited regarding the incidence of and risk factors for HE among contemporary patients in the context of the shifting epidemiology of cirrhosis. We examined a 20% random sample of U.S. Medicare enrollees with cirrhosis and Part D prescription coverage from 2008 to 2014. We modelled incident HE using demographic, clinical, and pharmacologic data. Risk factors for HE were evaluated, including demographics/socioeconomics, cirrhosis etiology, severity of liver disease, and pharmacotherapy, along with gastroenterology consultation, as time-varying covariates...

Strongyloidiasis, caused by Strongyloides stercoralis infection, is an important neglected tropical disease that causes significant public health problems in the tropics and subtropics. The disease can persist in hosts for decades and may be life-threatening because of hyperinfection and dissemination. Ivermectin (mostly) and albendazole are the most common anthelmintics used for treatment. Albendazole is suboptimal for this parasite, and although ivermectin is quite effective in immunocompromised patients, a multiple-course regimen is required...

DNA transformation of parasitic nematodes enables novel approaches to validating predictions from genomic and transcriptomic studies of these important pathogens. Notably, proof of principle for CRISPR/Cas9 mutagenesis has been achieved in Strongyloides spp., allowing identification of molecules essential to the functions of sensory neurons that mediate behaviors comprising host finding, invasion, and location of predilection sites by parasitic nematodes. Likewise, CRISPR/Cas9 knockout of the developmental regulatory transcription factor Ss-daf-16 has validated its function in regulating morphogenesis of infective third-stage larvae in Strongyloides stercoralis ...

BACKGROUND: In patients with CKD, the risk of developing colorectal cancer is high and outcomes are poor. Screening using fecal immunochemical testing (FIT) is effective in reducing mortality from colorectal cancer, but performance characteristics of FIT in CKD are unknown. METHODS: To determine the detection rates and performance characteristics of FIT for advanced colorectal neoplasia (ACN) in patients with CKD, we used FIT to prospectively screen patients aged 35-74 years with CKD (stages 3-5 CKD, dialysis, and renal transplant) from 11 sites in Australia, New Zealand, Canada, and Spain...

BACKGROUND AND AIM: Hepatocellular carcinoma (HCC) can still develop in chronic hepatitis B (CHB) patients receiving antiviral treatment. Serum Mac-2-binding protein glycosylation isomer (M2BPGi) is a novel marker for liver fibrosis. We investigated its role on incidence of HCC in entecavir (ETV)-treated CHB patients. METHODS: We identified HCC cases diagnosed at ≥ 1 year of ETV treatment. CHB patients without HCC (matched for age, gender, baseline hepatitis B virus-DNA, and duration of ETV treatment) were identified in approximately 1:2 ratio (HCC: non-HCC) for comparison...

Nematodes belong to one of the most diverse animal phyla. However, functional genomic studies in nematodes, other than in a few species, have often been limited in their reliability and success. Here we report that by combining liposome-based technology with microinjection, we were able to establish a wide range of genomic techniques in the newly described nematode genus Auanema. The method also allowed heritable changes in dauer larvae of Auanema, despite the immaturity of the gonad at the time of the microinjection...

BACKGROUND & AIMS: Seroclearance of hepatitis B surface antigen (HBsAg) is a marker for clearance of chronic hepatitis B virus (HBV) infection, but reported annual incidence rates of HBsAg seroclearance vary. We performed a systematic review and meta-analysis to provide more precise estimates of HBsAg seroclearance rates among subgroups and populations. METHODS: We searched PubMed, Embase, and the Cochrane library for cohort studies that reported HBsAg seroclearance in adults with chronic HBV infection with more than 1 year of follow-up and at least 1 repeat test for HBsAg...

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Islet β-cells are responsible for secreting all circulating insulin in response to rising plasma glucose concentrations. These cells are a phenotypically diverse population that express great functional heterogeneity. In mice, certain β-cells (termed 'hubs') have been shown to be crucial for dictating the islet response to high glucose, with inhibition of these hub cells abolishing the coordinated Ca2+ oscillations necessary for driving insulin secretion. These β-cell hubs were found to be highly metabolic and susceptible to pro-inflammatory and glucolipotoxic insults...

Strongyloides stercoralis is a human parasite that can cause a long-term infection. In immunosuppressed patients, strongyloidiasis may be fatal when there is overwhelming autoinfection resulting in the migration of large numbers of larvae through many organs. Definitive diagnosis is still a challenge, and a combination of symptoms, microscopic identification, and serology test results are often used to arrive at a clinical decision. However, intermittent larval excretion, low parasite burden, and occult infections are challenges with parasitological diagnosis of infection with S...

Strongyloides stercoralis hyperinfection causes high mortality rates in humans, and, while hyperinfection can be induced by immunosuppressive glucocorticoids, the pathogenesis remains unknown. Since immunocompetent mice are resistant to infection with S. stercoralis , we hypothesized that NSG mice, which have a reduced innate immune response and lack adaptive immunity, would be susceptible to the infection and develop hyperinfection. Interestingly, despite the presence of large numbers of adult and first-stage larvae in S...

Splinkerette PCR (spPCR) is a newly developed and efficient method to ascertain and characterize genomic insertion sites of transgenes. The method described in this protocol was successfully applied to confirm piggyBac transposon-mediated integration of transgenes into chromosomes of the parasitic nematode Strongyloides ratti . This work is described in detail in Shao et al . (2012) and presented here in a simplified diagram (Figure 1). Using this method, chromosomal loci of integration were determined based on target site and 5'- and 3' flanking sequences...

RIO kinases are essential atypical protein kinases in diverse prokaryotic and eukaryotic organisms, playing significant roles in yeast and humans. However, little is known about their functions in parasitic nematodes. In the present study, we have isolated and characterized the full-length cDNA, gDNA and a putative promoter of a RIOK-2 protein kinase (Ss-RIOK-2) encoding gene (Ss-riok-2) from Strongyloides stercoralis, a medically important parasitic nematode (Order Rhabditida). A three-dimensional structure (3D) model of Ss-RIOK-2 was generated using the Chaetomium thermophilum RIOK-2 protein kinase (Ct-RIOK-2) crystal structure 4GYG as a template...