Sensitive poliovirus detection using nested PCR and nanopore sequencing: a prospective validation study.

Timely detection of outbreaks is needed for poliovirus eradication, but gold standard detection in the Democratic Republic of the Congo takes 30 days (median). Direct molecular detection and nanopore sequencing (DDNS) of poliovirus in stool samples is a promising fast method. Here we report prospective testing of stool samples from suspected polio cases, and their contacts, in the Democratic Republic of the Congo between 10 August 2021 and 4 February 2022. DDNS detected polioviruses in 62/2,339 (2.7%) of samples, while gold standard combination of cell culture, quantitative PCR and Sanger sequencing detected polioviruses in 51/2,339 (2.2%) of the same samples. DDNS provided case confirmation in 7 days (median) in routine surveillance conditions. DDNS enabled confirmation of three serotype 2 circulating vaccine-derived poliovirus outbreaks 23 days (mean) earlier (range 6-30 days) than the gold standard method. The mean sequence similarity between sequences obtained by the two methods was 99.98%. Our data confirm the feasibility of implementing DDNS in a national poliovirus laboratory.

Quantification of trunk and android lean mass using dual energy x-ray absorptiometry compared to magnetic resonance imaging after spinal cord injury.

OBJECTIVE: To determine whether dual energy x-ray absorptiometry (DXA) compared to magnetic resonance imaging (MRI) may accurately quantify trunk lean mass (LM) after chronic spinal cord injury (SCI) and to investigate the relationships between trunk LM, visceral adiposity, trunk fat mass and basal metabolic rate (BMR). DESIGN: Cross-sectional design and correlational analysis. SETTING: Research setting in a medical center. PARTICIPANTS: Twenty-two men with motor complete paraplegia (n = 14; T4-T11) and tetraplegia (n = 8; C5-C7) were recruited as part of a clinical trial. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Trunk and android LM were measured using DXA. The volume of six trunk muscle groups were then measured using MRI to quantify trunk LM-MRI. Subcutaneous and visceral adipose tissue (VAT) cross-sectional areas were also measured using MRI. After overnight fast, BMR was evaluated using indirect calorimetry. RESULTS: Trunk LM-DXA (24 ± 3.3 kg) and android LM-DXA (3.6 ± 0.7 kg) overestimated (P < 0.0001) trunk LM-MRI (1.7 ± 0.5 kg). Trunk LM-MRI = 0.088* log (trunk LM-DXA)-0.415; r2=0.29, SEE= 0.44 kg, P = 0.007. Trunk LM-MRI = 1.53* android LM-DXA + 0.126; r2=0.26, SEE= 0.21 kg, P = 0.018. Percentage trunk LM-MRI was inversely related to VAT (r=-0.79, P < 0.0001) and trunk fat mass (r=-0.83, P < 0.001). Only trunk LM-DXA was related to BMR (r = 0.61, P = 0.002). Persons with tetraplegia have 13% smaller trunk muscle cross-sectional areas (P = 0.036) compared to those with paraplegia. CONCLUSIONS: Trunk LM-DXA and android LM-DXA overestimated trunk LM-MRI. Percentage trunk LM-MRI, but not LM-DXA, was inversely related to trunk central adiposity. The findings highlight the importance of exercising trunk LM to attenuate cardio-metabolic disorders after SCI.

Liver Adiposity and Metabolic Profile in Individuals with Chronic Spinal Cord Injury.

PURPOSE: To quantify liver adiposity using magnetic resonance imaging (MRI) and to determine its association with metabolic profile in men with spinal cord injury (SCI). MATERIALS AND METHODS: MRI analysis of liver adiposity by fat signal fraction (FSF) and visceral adipose tissue (VAT) was completed on twenty participants. Intravenous glucose tolerance test was conducted to measure glucose effectiveness (Sg) and insulin sensitivity (Si). Lipid panel, fasting glucose, glycated hemoglobin (HbA1c), and inflammatory cytokines were also analyzed. RESULTS: Average hepatic FSF was 3.7% ± 2.1. FSF was positively related to TG, non-HDL-C, fasting glucose, HbA1c, VAT, and tumor necrosis factor alpha (TNF-α). FSF was negatively related to Si and testosterone. FSF was positively related to VAT (r = 0.48, p = 0.032) and TNF-α (r = 0.51, p = 0.016) independent of age, level of injury (LOI), and time since injury (TSI). The associations between FSF and metabolic profile were independent of VAT. CONCLUSIONS: MRI noninvasively estimated hepatic adiposity in men with chronic SCI. FSF was associated with dysfunction in metabolic profile, central adiposity, and inflammation. Importantly, liver adiposity influenced metabolic profile independently of VAT. These findings highlight the significance of quantifying liver adiposity after SCI to attenuate the development of metabolic disorders.

Connecting and Collaborating: Developing National Dental PBRN Study Concepts Through POD Engagement.

PURPOSE: This article illustrates the process by which the Southwest Region of the National Dental Practice-Based Research Network (www.NationalDentalPBRN.org) fosters collaboration among practitioners and researchers in study concept development through protocol development groups (PODs). The Southwest Region begins this process by engaging PODs, which comprise dentists, hygienists, and/or academic faculty who share research interests related to improving dental care. METHOD: The PODs use the Tuckman four-stage model of group development (forming, storming, norming, and performing) to develop study concepts. This well-structured model encourages engagement among group members and enables quality discussion through organized sessions. This model provides milestones for the group's progression and for the members' interactions. The Southwest Region Directors play a crucial role in guiding and directing the development of PODs by aligning the members' research interests with the goals of the National Network. RESULTS: POD engagement using Tuckman's stages has been successful in developing study concepts for submission to the National Network. Between 2012 and 2014, the Southwest Region has developed 14 PODs from 275 research ideas. Five of these study concepts have been submitted to the National Network for approval, including the Novel Tobacco Products POD, which showcases the applicability of Tuckman's model. CONCLUSION: Overall, the POD concept is a collaborative effort that brings together practitioners and academicians through shared research interests and capitalizes on participants' expertise and experiences. The Southwest Region will continue to develop PODs to foster new ideas for future studies in the Network.

Influence of continuing education on dental hygienists' knowledge and behavior related to oral cancer screening and tobacco cessation.

PURPOSE: There are more than 35,000 new cases of oral and pharyngeal cancers (OPC) diagnosed each year. Most OPCs are diagnosed in advanced stages, requiring aggressive treatment and resulting in higher morbidity and mortality than when diagnosed early. The overall 5 year survival rate of OPC is about 60%. Early detection of OPC lesions are the key to survival. A major risk factor for OPC is chronic tobacco use. The purpose of this paper is to report changes in dental hygienists' knowledge, attitudes and behaviors 6 months after attending a standardized lecture format continuing education (CE) course on early OPC detection and tobacco cessation counseling compared to baseline values. METHODS: A total of 64 CE courses were given for dental professionals throughout the 10 U.S. public health districts to determine if OPC screenings and tobacco cessation counseling behaviors could be modified at 6 months post-training. Questionnaires were obtained at baseline and 6 months later using a pre-/post-test design. RESULTS: A total of 1,463 dental hygienists participated at baseline and 543 at a 6 month follow-up. Data showed a significant difference in knowledge and behavior compared to baseline values. CONCLUSION: CE appeared to have a significant influence on participants' OPC and tobacco cessation knowledge and behavior, and could potentially make a difference on prevention, early detection and ultimately on OPC control.

Hostile takeover by Plasmodium: reorganization of parasite and host cell membranes during liver stage egress.

The protozoan parasite Plasmodium is transmitted by female Anopheles mosquitoes and undergoes obligatory development within a parasitophorous vacuole in hepatocytes before it is released into the bloodstream. The transition to the blood stage was previously shown to involve the packaging of exoerythrocytic merozoites into membrane-surrounded vesicles, called merosomes, which are delivered directly into liver sinusoids. However, it was unclear whether the membrane of these merosomes was derived from the parasite membrane, the parasitophorous vacuole membrane or the host cell membrane. This knowledge is required to determine how phagocytes will be directed against merosomes. Here, we fluorescently label the candidate membranes and use live cell imaging to show that the merosome membrane derives from the host cell membrane. We also demonstrate that proteins in the host cell membrane are lost during merozoite liberation from the parasitophorous vacuole. Immediately after the breakdown of the parasitophorous vacuole membrane, the host cell mitochondria begin to degenerate and protein biosynthesis arrests. The intact host cell plasma membrane surrounding merosomes allows Plasmodium to mask itself from the host immune system and bypass the numerous Kupffer cells on its way into the bloodstream. This represents an effective strategy for evading host defenses before establishing a blood stage infection.

Long astral microtubules uncouple mitotic spindles from the cytokinetic furrow.

Astral microtubules (MTs) are known to be important for cleavage furrow induction and spindle positioning, and loss of astral MTs has been reported to increase cortical contractility. To investigate the effect of excess astral MT activity, we depleted the MT depolymerizer mitotic centromere-associated kinesin (MCAK) from HeLa cells to produce ultra-long, astral MTs during mitosis. MCAK depletion promoted dramatic spindle rocking in early anaphase, wherein the entire mitotic spindle oscillated along the spindle axis from one proto-daughter cell to the other, driven by oscillations of cortical nonmuscle myosin II. The effect was phenocopied by taxol treatment. Live imaging revealed that cortical actin partially vacates the polar cortex in favor of the equatorial cortex during anaphase. We propose that this renders the polar actin cortex vulnerable to rupture during normal contractile activity and that long astral MTs enlarge the blebs. Excessively large blebs displace mitotic spindle position by cytoplasmic flow, triggering the oscillations as the blebs resolve.

Imaging liver-stage malaria parasites.

Plasmodium parasites, the causative agents of malaria, first invade and develop within hepatocytes before infecting red blood cells and causing symptomatic disease. Because of the low infection rates in vitro and in vivo, the liver stage of Plasmodium infection is not very amenable to biochemical assays, but the large size of the parasite at this stage in comparison with Plasmodium blood stages makes it accessible to microscopic analysis. A variety of imaging techniques has been used to this aim, ranging from electron microscopy to widefield epifluorescence and laser scanning confocal microscopy. High-speed live video microscopy of fluorescent parasites in particular has radically changed our view on key events in Plasmodium liver-stage development. This includes the fate of motile sporozoites inoculated by Anopheles mosquitoes as well as the transport of merozoites within merosomes from the liver tissue into the blood vessel. It is safe to predict that in the near future the application of the latest microscopy techniques in Plasmodium research will bring important insights and allow us spectacular views of parasites during their development in the liver.

Tobacco cessation education for dentists: an evaluation of the lecture format.

Dentists with tobacco cessation training perform more interventions, report increased self-efficacy, preparedness and fewer barriers than those without training. The aim of this study was to assess changes in knowledge, attitudes and behavior of dentists (CE group) at six months following presentation of a standardized tobacco cessation lecture module. These data were compared to those from age and gender-matched controls who did not receive training. The CE group was more likely to feel cessation was very important, score higher on knowledge questions, update tobacco use of continuing patients, ask former smokers about relapse and ask about daily consumption. The CE group was also more likely to discuss the personal relevance of quitting, roadblocks and setting quit dates, identify triggers, discuss pharmacotherapy and provide follow-up. These results suggest that group education appears to be a cost-efficient and effective method of teaching dentists about the latest methods of tobacco cessation.

In vitro and in vivo analysis of microtubule-destabilizing kinesins.

Cellular microtubules are rigid in comparison to other cytoskeletal elements (1,2). To facilitate cytoplasmic remodeling and timely responses to cell signaling events, microtubules depolymerize and repolymerize rapidly at their ends (3). These dynamic properties are critically important for many cellular functions, such as spindle assembly, the capture and segregation of chromosomes during cell division and cell motility. Microtubule dynamics are spatially and temporally controlled in the cell by accessory proteins. Molecular motor proteins of the kinesin superfamily that act to destabilize microtubules play important roles in this regulation (4).

Use of computer technology to modify objective structured clinical examinations.

Objective structured clinical examinations (OSCEs) are multistationed clinical examinations that have been shown to be effective in testing students' ability to integrate the knowledge, skills, and attitudes acquired during their preclinical and clinical training and experiences. The original OSCE for the third-year Preventive Dentistry course at Baylor College of Dentistry was based on the traditional format consisting of four sections of twelve stations with a group of twelve students rotating through each of the sections simultaneously. This arrangement allowed for examination of one-half of the class. The other half of the class took the exam on an alternate date. To reduce the disruption caused by the students' moving from station to station and to allow for examination of the entire class in one setting, the traditional concept was modified using computer technology, and the twelve stations "moved" via a PowerPoint presentation while students remained stationary. Questions on both exams provided a means for testing data interpretation, diagnostic skills, and, to some extent, interpersonal skills. The overall atmosphere during the computer-based examination was less chaotic. Each student received identical instructions, explanations, and time allotments to respond to the information presented. The ratio of faculty to students required to monitor the exam was less than required for the traditional format. Additionally, since there was no need to allow time for student transition, the total time required to administer the exam was reduced. Thus, objective assessment of the entire class was accomplished using fewer faculty members and less class time and with less disruption for the students.

MCAK associates with the tips of polymerizing microtubules.

MCAK is a member of the kinesin-13 family of microtubule (MT)-depolymerizing kinesins. We show that the potent MT depolymerizer MCAK tracks (treadmills) with the tips of polymerizing MTs in living cells. Tip tracking of MCAK is inhibited by phosphorylation and is dependent on the extreme COOH-terminal tail of MCAK. Tip tracking is not essential for MCAK's MT-depolymerizing activity. We propose that tip tracking is a mechanism by which MCAK is preferentially localized to regions of the cell that modulate the plus ends of MTs.