Postural Control under Cognitive Load: Evidence of Increased Automaticity Revealed by Center-of-Pressure and Head Kinematics.

How postural responses change with sensory perturbations while also performing a cognitive task is still debatable. This study investigated this question via comprehensive assessment of postural sway, head kinematics and their coupling. Twenty-three healthy young adults stood in tandem with eyes open or wearing the HTC Vive Head-Mounted Display (HMD) with a static or dynamic (i.e., movement in the anterior-posterior direction at 5 mm or 32 mm at 0.2 Hz) 3-wall stars display. On half of the trials, participants performed a cognitive serial subtraction task. Medio-lateral center-of-pressure (COP) path significantly increased with the cognitive task, particularly with dynamic visuals whereas medio-lateral variance decreased with the cognitive task. Head path and velocity significantly increased with the cognitive task in both directions while variance decreased. Head-COP cross-correlations ranged between 0.78 and 0.66. These findings, accompanied by frequency analysis, suggest that postural control switched to primarily relying on somatosensory input under challenging cognitive load conditions. Several differences between head and COP suggest that head kinematics contribute an important additional facet of postural control and the relationship between head and COP may depend on task and stance position. The potential of HMDs for clinical assessments of balance needs to be further explored.

Molecular characterisation of group A streptococcus isolates recovered from the north-west of Pretoria, South Africa.

BACKGROUND: Group A streptococcus (GAS) is a human pathogen responsible for a wide range of invasive and non-invasive infections. Pharyngitis caused by GAS may have complications such as acute rheumatic fever subsequently leading to rheumatic heart disease (RHD). RHD continues to have high morbidity and mortality and affects millions of children and young adults, mostly in developing countries. An effective preventive vaccine against GAS may reduce the morbidity and mortality. A 30-valent M-protein-based vaccine is currently at the clinical trials stage of development. Potential vaccine coverage will depend on the geographical distribution of GAS emm (M protein) types. OBJECTIVES: To determine the emm types of GAS isolates circulating in the north-west of Pretoria, South Africa. METHODS: Throat swabs were collected from patients aged 3 - 20 years presenting with pharyngitis at one local clinic. In addition, GAS clinical isolates were collected from the National Health Laboratory Service diagnostic laboratory. Emm genotyping was done on the GAS isolates by amplification of the emm gene followed by sequencing of the 5' portion of the gene. The emm types were correlated with the types in the vaccine. RESULTS: A total of 54 GAS isolates were collected, comprising 19 pharyngitis and 35 clinical isolates. We found 15 different emm types among the 43 GAS isolates that were successfully sequenced. Eleven isolates (20%) could not be typed. The most prevalent emm type was 92 (26%), which is part of the 30-valent vaccine. This was followed by emm 25 and 75, each accounting for 12% of the isolates. Up to 67% of the emm types are not covered in the 30-valent vaccine. CONCLUSIONS: Fifteen emm types were identified, of which 92 was the most prevalent. It is concerning that 67% of the emm types are not covered in the vaccine currently under development. It is recommended that surveillance studies be extended to include other parts of the country in order to expand knowledge of the circulating emm types.

Central retinal artery occlusion associated with patent foramen ovale: a case report and literature review / Oclusão da artéria central da retina associada ao forame oval patente: relato de caso e revisão de literatura

ABSTRACT Patent foramen ovale might cause cryptogenic strokes, including retinal artery occlusion. Herein, we describe a previously healthy young man who presented with central retinal artery occlusion in the setting of patent foramen ovale and explore the need for transesophageal echocardiogram for its diagnosis. Cardiovascular workup and neuroimaging were unremarkable. Transthoracic echocardiogram bubble study revealed a right to left atrial shunt and subsequent transesophageal echocardiogram disclosed patent foramen ovale. This congenital cardiac anomaly was the likely conduit for a thrombo-embolic central retinal artery occlusion. We identified seven patients with patent foramen ovale associated with central retinal artery occlusion in the literature. Transthoracic echocardiogram was diagnostic in only one patient (14.3%), whereas transesophageal echocardiogram was required to reveal patent foramen ovale in the remaining six (85.7%). Our case and the previous reports support the link between central retinal artery occlusion and patent foramen ovale. Therefore, providers should consider the more sensitive transesophageal echocardiogram during the initial evaluation of young patients without immediately identifiable causes of retinal artery occlusion.

RESUMO O forame oval patente pode estar associado a derrames criptogênicos que incluem a oclusão da artéria retiniana. Descrevemos aqui um jovem previamente saudável que apresentou oclusão da artéria central da retina associada ao forame oval patente, sendo considerado portanto, a necessidade de um ecocardiograma transesofágico para seu diagnóstico. A avaliação cardiovascular e a neuroimagem não foram significativas. O estudo da bolha no ecocardiograma transtorácico revelou um shunt atrial direito-esquerdo e o ecocardiograma transesofágico subsequente revelou um forame oval patente. Esta anomalia cardíaca congênita foi o provável conduíte para uma oclusão tromboembólica da artéria central retiniana Na literatura, foram identificadossete pacientes com forame oval patente associado à oclusão da artéria central retiniana. O ecocardiograma transtorácico diagnosticou apenas um paciente (14,3%), enquanto o ecocardiograma transesofágico foi necessário para revelar o forame oval patente nos seis casos restantes (85,7%). Nosso caso e relatos anteriores suportam a ligação entre a oclusão da artéria central retiniana e o forame oval patente. Os profissionais devem considerar, como sendo mais sensível, o ecocardiograma transesofágico na avaliação inicial de pacientes jovens sem causas imediatamente identificáveis de oclusões da artéria retiniana.

Central retinal artery occlusion associated with patent foramen ovale: a case report and literature review.

Patent foramen ovale might cause cryptogenic strokes, including retinal artery occlusion. Herein, we describe a previously healthy young man who presented with central retinal artery occlusion in the setting of patent foramen ovale and explore the need for transesophageal echocardiogram for its diagnosis. Cardiovascular workup and neuroimaging were unremarkable. Transthoracic echocardiogram bubble study revealed a right to left atrial shunt and subsequent transesophageal echocardiogram disclosed patent foramen ovale. This congenital cardiac anomaly was the likely conduit for a thrombo-embolic central retinal artery occlusion. We identified seven patients with patent foramen ovale associated with central retinal artery occlusion in the literature. Transthoracic echocardiogram was diagnostic in only one patient (14.3%), whereas transesophageal echocardiogram was required to reveal patent foramen ovale in the remaining six (85.7%). Our case and the previous reports support the link between central retinal artery occlusion and patent foramen ovale. Therefore, providers should consider the more sensitive transesophageal echocardiogram during the initial evaluation of young patients without immediately identifiable causes of retinal artery occlusion.

People with persistent postural-perceptual dizziness demonstrate altered postural strategies in complex visual and cognitive environments.

BACKGROUND: People with PPPD report imbalance, increase in symptoms and impaired function within complex visual environments, but understanding of the mechanism for these behaviors is still lacking. OBJECTIVE: To investigate postural control in PPPD we compared changes in center of pressure (COP) and head kinematics of people with PPPD (N = 22) and healthy controls (N = 20) in response to different combinations of visual and cognitive perturbations during a challenging balance task. METHODS: Participants stood in a tandem position. Static or moving stars (0.2 Hz, 5 mm or 32 mm amplitude, anterior-posterior direction) were displayed through a head-mounted display (HTC Vive). On half the trials, participants performed a serial-3 subtraction task. We measured medio-lateral and anterior-posterior path and acceleration of COP and head. RESULTS: Controls significantly increased all COP and head parameters with the cognitive task whereas PPPD increased only COP ML path and acceleration. Only controls significantly increased head anterior-posterior & medio-lateral acceleration with moving visual load. Cognitive task performance was similar between groups. CONCLUSIONS: We observed altered postural strategies in people with PPPD, in the form of reduced movement with challenge, particularly around the head segment. The potential of this simple and portable head-mounted display setup for differential diagnosis of vestibular disorders should be further explored.

Factors associated with dynamic balance in people with Persistent Postural Perceptual Dizziness (PPPD): a cross-sectional study using a virtual-reality Four Square Step Test.

BACKGROUND: Persistent postural-perceptual dizziness (PPPD) is a condition characterized by chronic subjective dizziness and exacerbated by visual stimuli or upright movement. Typical balance tests do not replicate the environments known to increase symptoms in people with PPPD-crowded places with moving objects. Using a virtual reality system, we quantified dynamic balance in people with PPPD and healthy controls in diverse visual conditions. METHODS: Twenty-two individuals with PPPD and 29 controls performed a square-shaped fast walking task (Four-Square Step Test Virtual Reality-FSST-VR) using a head-mounted-display (HTC Vive) under 3 visual conditions (empty train platform; people moving; people and trains moving). Head kinematics was used to measure task duration, movement smoothness and anterior-posterior (AP) and medio-lateral (ML) ranges of movement (ROM). Heart rate (HR) was monitored using a chest-band. Participants also completed a functional mobility test (Timed-Up-and-Go; TUG) and questionnaires measuring anxiety (State-Trait Anxiety Inventory; STAI), balance confidence (Activities-Specific Balance Confidence; ABC), perceived disability (Dizziness Handicap Inventory) and simulator sickness (Simulator Sickness Questionnaire). Main effects of visual load and group and associations between performance, functional and self-reported outcomes were examined. RESULTS: State anxiety and simulator sickness did not increase following testing. AP-ROM and HR increased with high visual load in both groups (p < 0.05). There were no significant between-group differences in head kinematics. In the high visual load conditions, high trait anxiety and longer TUG duration were moderately associated with reduced AP and ML-ROM in the PPPD group and low ABC and  high perceived disability were associated with reduced AP-ROM (|r| = 0.47 to 0.53; p < 0.05). In contrast, in controls high STAI-trait, low ABC and longer TUG duration were associated with increased AP-ROM (|r| = 0.38 to 0.46; p < 0.05) and longer TUG duration was associated with increased ML-ROM (r = 0.53, p < 0.01). CONCLUSIONS: FSST-VR may shed light on movement strategies in PPPD beyond task duration. While no main effect of group was observed, the distinct associations with self-reported and functional outcomes, identified using spatial head kinematics, suggest that some people with PPPD reduce head degrees of freedom when performing a dynamic balance task. This supports a potential link between spatial perception and PPPD symptomatology.

Antibacterial prophylaxis with ciprofloxacin for patients with multiple myeloma and lymphoma undergoing autologous haematopoietic cell transplantation: a quasi-experimental single-centre before-after study.

OBJECTIVES: We aimed to study whether ciprofloxacin prophylaxis reduces infectious complications in patients undergoing autologous haematopoietic cell transplantation (AHCT). METHODS: This is a quasi-experimental, retrospective, before-after study. We compared the incidence of bacterial-related complications among 356 patients with multiple myeloma (MM) (n = 202) and lymphoma (n = 154) who underwent AHCT with (n = 177) or without (n = 179) ciprofloxacin prophylaxis between 03/2007 and 10/2012 and between 10/2012 and 07/2016, respectively, at a single centre. RESULTS: Febrile neutropaenia, bacteraemia, and pneumonia were significantly more common among patients who underwent AHCT during the second study period and did not receive antibacterial prophylaxis compared with patients who underwent AHCT during the first study period and received antibacterial prophylaxis (89.9% (161/179) vs. 83.1% (147/177), difference 6.9%, 95% CI 0-14.1%, P = 0.002; 15.1% (27/179) vs. 4.5% (8/177), difference 10.6%, 95% CI 4.4-16.9%, p < 0.0001; 12.3% (22/179) vs. 6.2% (11/177), difference 6.1%, 95% CI 0-12.3%, p = 0.04, respectively). The number-needed-to-treat to prevent one episode of bacteraemia, pneumonia, and febrile neutropaenia was 8.6, 8.5, and 13.7, respectively. Patients with ciprofloxacin prophylaxis had higher rates of ciprofloxacin-resistant bacteraemia (62.5% (5/8) vs. 18.5% (5/27), difference 44%, 95% CI 7-70%, p = 0.01). In multivariate analysis, ciprofloxacin prophylaxis significantly decreased the odds of bacteraemia (OR 0.19, 95% CI 0.07-0.52; p < 0.0001) and pneumonia (OR 0.37, 95% CI 0.16-0.85, p = 0.02). CONCLUSION: According to our single-centre experience, patients with MM and lymphoma undergoing AHCT may benefit from antibacterial prophylaxis with ciprofloxacin.

What every dentist needs to know about cannabis.

As the prevalence of marijuana use rises along with its legalization, it has become increasingly important for dentists to understand the potential benefits and risks of marijuana use. This article reviews potential effects of cannabis on oral and systemic health.

What every dentist needs to know about obesity and oral health.

Obesity has an adverse effect on the body as a whole and greatly increases an individual's risk for numerous diseases, including type 2 diabetes, coronary artery disease, stroke, and cancer. In addition, the link between diabetes and periodontitis has been well documented, and possible links between obesity and other oral health problems, such as caries, are being investigated. As more has been learned about the association between periodontal disease and other inflammatory diseases, including obesity, dentists have gained greater responsibility in the prevention and treatment of chronic diseases. Dentists should be aware of the early signs of obesity and its oral manifestations and equipped with the proper knowledge to educate their patients. This article reviews recent findings on obesity and its relationship to other diseases and in particular to oral health.

Baylisascaris procyonis and Herpes Simplex Virus 2 Coinfection Presenting as Ocular Larva Migrans with Granuloma Formation in a Child.

Ocular Baylisascaris procyonis infection results from ingestion of infective eggs of B. procyonis, the raccoon ascarid. Herpes simplex virus type 2 (HSV-2) infection of the retina is the result of either primary infection or reactivated disease. Herein, we report a case of a 12-year-old female resident of the Bronx in New York City, who presented with pan-uveitis and vision loss. Initial evaluation for etiologic causes was nondiagnostic. Serology for anti-Baylisascaris procyonis antibodies in serum and vitreous fluid were both positive. Polymerase chain reaction (PCR) of vitreous fluid was positive for HSV-2. Treatment with vitrectomy, albendazole, and acyclovir resulted in mild improvement of visual acuity. The atypical presentation of B. procyonis in this case, as ocular larva migrans with a peripheral granuloma and retinal detachment, underscores the importance of maintaining a high degree of suspicion for this pathogen even in non-diffuse unilateral subacute neuroretinitis (DUSN) patients in urban areas. This case further illustrates that it is possible to have coexisting infections in cases of posterior uveitis.

Normal mode dynamics of voltage-gated K(+) channels: gating principle, opening mechanism, and inhibition.

Voltage-dependent potassium channels open in response to changes in membrane potential and become partially inactivated upon binding of inhibitors. Here we calculate normal mode motion of two voltage-dependent K(+) channels, KvAP and Shaker, and their complexes with inhibitors and address the gating principle, opening mechanism, and inhibition. The normal modes indicate that pore expansion and channel opening is correlated with a displacement of the arginine gating charges and a tilting of the voltage-sensor paddles. Normal modes of Shaker in complex with agitoxin, which blocks the central pore, do not display significantly altered paddle tilting and pore expansion. In contrast, normal modes of Shaker in complex with hanatoxin, which binds to the voltage sensor paddle, display decreased paddle tilting and pore expansion. This study presents a unified motion for the gating principle and channel opening, and offers insight into the voltage sensor paddle motion and its inhibition.

What every dentist should know about tea.

Tea is one of the most frequently consumed beverages in the world, second only to water. Repeated media coverage about the positive health benefits of tea has renewed interest in the beverage, particularly among Americans. This article reviews the general and specific benefits of drinking tea, as well as the potential negative aspects of tea consumption.

Long-term persistence of IgE anti-influenza A HIN1 virus antibodies in serum of children and adults following influenza A vaccination with subsequent H1N1 infection: a case study.

BACKGROUND AND METHODS: The role of immunoglobulin (Ig) E in immunity against influenza A H1N1 has not been studied. Total serum IgE and specific IgE and IgG anti-H1N1 virus responses were studied in children and adults (n = 2) who received influenza virus vaccination (Flumist(®) or Fluzone(®) ) in autumn 2008 and 2009, and then subsequently became infected with the H1N1 virus in spring 2009. Twelve months after infection, antibodies in their serum were compared with those in the serum of subjects who were either vaccinated but not infected (n = 4) or nonvaccinated and noninfected subjects (n = 2), using UniCAP total IgE fluoroenzyme immunoassay, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and Western blotting. Band sizes for the influenza virus (58, 56, 40, 30, 25, and 17 kDa) and H1N1 viral proteins (58, 56, 25, and 17 kDa) were determined, using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Coomassie brilliant blue. RESULTS: We found that the serum of vaccinated and subsequently infected children and adults contained IgE and IgG antibodies to both H1N1 and influenza virus, with a strong IgE and IgG band intensity at 56 kDa. Interestingly, in subjects who were vaccinated but not infected, band intensity at 56 kDa was lowered by approximately two-fold. Serum of nonvaccinated and noninfected subjects had no detectable IgE or IgG antibodies to influenza virus or H1N1. CONCLUSION: This is the first description of IgE anti-influenza A H1N1 antibodies in human serum and the first demonstration of their long-term persistence. The decreased intensity of the 56 kDa band in vaccinated noninfected subjects compared with vaccinated infected subjects suggests augmented IgE and IgG antibody responses to influenza A H1N1.

Preliminary clinical evaluation of a noninvasive device for the measurement of coagulability in the elderly.

The feasibility of the noninvasive assessment of blood 'coagulability' (the tendency to coagulate) has been tested by using a novel device, the Thrombo-Monitor. It monitors, by using the principles of near infra-red (NIR) dynamic light scattering, the tendency of blood to create clots. The Thrombo-Monitor observes the very initial changes of blood viscosity, which occurs due to the temporarily induced stasis of capillary blood of the finger. One hundred and fifteen patients aged >65 years (matched by age and sex) participated in the study. Patients were initially divided into four groups based on the patient's medical therapy. The study groups were: warfarin, enoxaparin, aspirin and/or clopidogrel, and a control group. The medications were given according to the patient's comorbidities (eg, atrial fibrillation [AF], status post pulmonary embolism [S/p PE], status post cerebrovascular accident [S/p CVA]). The Thrombo-Monitor Index (TMI) is a noninvasive index, derived on the basis of laboratory test results of international normalized ratio (INR) and prothrombin time (PT) values. For the group of patients who were treated only with warfarin, TMI was adjusted by using the jackknife statistical approach to create maximum correlation and linearity with INR and PT values that ranged from 1.1 to 5.0. For all warfarin patients (N = 35) the TMI was found to have a good correlation with INR and PT values (R(2) = 0.64, P < 0.00001); mean TMI = 1.86 (SD = 0.91); mean INR and PT = 2.3 (SD = 0.91). The calibration curve thus generated was used to calculate the TMI for all other groups: aspirin group, mean TMI = 1.3 (SD = 0.14, N = 23), corresponding approximately to INR and PT values of 1.036; enoxaparin group (N = 24), mean TMI = 1.34 (SD = 0.304), corresponding to mean INR and PT values of 1.07 (SD = 0.3); control group, INR and PT ≥ 1 (N = 32), mean TMI = 1.24 (SD = 0.32). R(2) of all control and warfarin patients (N = 67) was 0.55 (P < 0.00001). In summary, the newly introduced TMI index is significantly correlated with INR and PT values.

Structure of microemulsions with gemini surfactant studied by solvatochromic probe and diffusion NMR.

The structure of microemulsions prepared by the anionic gemini surfactant didodecyl diphenyl ether disulfonate (C12-DADS) was investigated by a solvatochromic probe and nuclear magnetic resonance (NMR) diffusion measurements. The NMR measurements indicate the presence of bicontinuous and oil-in-water microemulsions depending on microemulsion composition. The absorbance spectra of the solvatochromic probe, Nile red, indicate the solubilization of the probe in different sites, in agreement with the NMR findings. It was also found that the microemulsions were capable of dissolving the hydrophobic probe, Nile red, up to four times better than expected if it were simply dissolved in the toluene phase.

Vaginal birth after cesarean section: trial of labor or repeat cesarean section? A decision analysis.

OBJECTIVE: The risk of perinatal death associated with labor after previous cesarean section appears higher than with a repeated cesarean section. On the other hand, repeated cesarean sections are associated with increased maternal morbidity and mortality from placental pathologic conditions (previa or accreta) on subsequent pregnancies. The study was undertaken to analyze the decision for a trial of labor or a repeated cesarean section, after a prior cesarean section, with varying desire for an additional pregnancy. STUDY DESIGN: A model was formulated using a decision tree, based on the reported risks of the two approaches. Sensitivity analysis was performed over a variety of probabilities (eg, chance of uterine rupture or neonatal death, chance of rescue cesarean section, desire for an additional pregnancy) and utilities (eg, use of hysterectomy or neonatal death). RESULTS: The model favors a trial of labor if it has a chance of success of 50% or above and if the wish for additional pregnancies after a cesarean section is estimated at near 10% to 20% or above because the delayed risks from a repeated cesarean section are greater than its immediate benefit. The model was robust over a wide range of assumptions. CONCLUSION: An optimal decision for a trial of labor or a repeated cesarean section is substantially determined by the wish for future pregnancies. The default option of a repeated cesarean section is not directly applicable in populations in which family planning often extends over two children.

Tc99m macroaggregated albumin cisternography for the detection of persistent cerebrospinal fluid (CSF) leak in an animal model.

The present study describes a new in vivo animal model that enables the detection of cerebrospinal fluid (CSF) leakage after dural injury. A polyethylene catheter (PE 10) was inserted into the subarachnoid space in the lumbar area by a simple surgical procedure and a radioactive isotope Tc99m Macroaggregated Albumin (Tc99m MAA) was injected into the CSF. In the experimental group, a standardised dural puncture was performed in the cervical area. The accumulation of the isotope in the gauze placed over the dural puncture and viewed by a gamma camera as a spot of concentrated radioactivity, was indicative of CSF leakage. In a second group of animals with intact cervical dura the absence of leakage was presented as a picture of sporadic background radioactivity. To demonstrate the effectiveness of the model in detection of invisible leakage, blood was applied over the cervical dural defect in another group of animals and CSF leakage was assessed by the above mentioned isotope detection method. This in vivo model may be used for evaluation of the sealing properties of various materials under physiological and metabolic processes in living tissue.

The response of laying hens to induced molt as affected by strain and age.

Molt was induced in 502-d-old Lohmann, Hy-Line W-77, Yafa, and Yarkon strains of laying hens (Experiment 1), and at different ages during the 1st yr of production in the Lohmann strain (Experiment 2). The induced molt treatment included an 8-d feed withdrawal period followed by a 22-d rest period during which the birds received 60 or 70 g/d of a low-nutrient maintenance diet, in both experiments, respectively, and a reduced duration of daylight. In both experiments, induced molt resulted in an increase in postmolt egg production rate and a diminution of the rate of decline of production with age. The first eggs during the postmolt period were smaller than those of the unmolted birds but egg size increased rapidly to control levels. Egg breakage was markedly reduced by induced molt and its rate of increase with age was diminished. Postmolt feed intake was higher than that of the unmolted birds and body weights reached values higher than those of the controls. Those responses were not different among strains but the ranking among the strains in the molted group was similar to that of the unmolted controls, for all production traits. The postmolt rate of production approached that of first cycle peak and was not affected by treatment age. Shell quality as reflected by the percentage of breakage during the postmolt period was similar to that of the unmolted controls approximately 3 to 4 mo earlier.