Immune responses induced by the Leishmania (Leishmania) donovani A2 antigen,but not by the LACK antigen,are protective against experimental Leishmania (Leishmania) amazonensis infection

Leishmania amazonensis is one of the major etiologic agents of a broad spectrum of clinical forms of leishmaniasis and has a wide geographical distribution in the Americas, which overlaps with the areas of transmission of many other Leishmania species. The LACK and A2 antigens are shared by various Leishmania species. A2 was previously shown to induce a potent Th1 immune response and protection against L. donovani infection in BALB/c mice. LACK is effective against L. major infection, but no significant protection against L. donovani infection was observed, in spite of the induction of a potent Th1 immune response. In an attempt to select candidate antigens for an American leishmaniasis vaccine, we investigated the protective effect of these recombinant antigens (rLACK and rA2) and recombinant interleukin-12 (rIL-12) against L. amazonensis infection in BALB/c mice. As expected, immunization with either rA2-rIL-12 or rLACK-rIL-12 induced a robust Th1 response prior to infection. However, only the BALB/c mice immunized with rA2-rIL-12 were protected against infection. Sustained gamma interferon (IFN-gamma) production, high levels of anti-A2 antibodies, and low levels of parasite-specific antibodies were detected in these mice after infection. In contrast, mice immunized with rLACK-rIL-12 displayed decreased levels of IFN-gamma and high levels of both anti-LACK and parasite-specific antibodies. Curiously, the association between rA2 and rLACK antigens in the same vaccine completely inhibited the rA2-specific IFN-gamma and humoral responses and, consequently, the protective effect of the rA2 antigen against L. amazonensis infection. We concluded that A2, but not LACK, fits the requirements for a safe vaccine against American leishmaniasis.     

On the ERN and the significance of errors

The error-related negativity (ERN) is an event-related brain potential observed when subjects commit errors. To examine whether the ERN is sensitive to the value of errors, the motivational significance of errors was manipulated in two experiments. In Experiment 1, low and high monetary value errors were compared to evaluate the effect of trial value on the ERN. In Experiment 2, subjects performed a flanker task both while their performance was being evaluated and during a control condition. Consistent with the notion that the error-detection system is sensitive to the significance of errors, the ERN was significantly larger on high-value trials in Experiment 1 and during evaluation in Experiment 2. There were no corresponding effects on the correct response negativity, and no behavioral differences between conditions were evident in either experiment. These results are discussed in terms of the functional role of the ERN in response monitoring.     

Choroidal vasculature in diabetic rats

This study aims to evaluate the diabetic influence on the choroidal vessels morphology. Twenty Wistar rats were divided into a control (CG) and a diabetic group (DG). The animals had the diabetes induced by an intra-venous injection of Alloxan (42 mg/kg). Transmission electron microscopy analysis focusing the choroidal vessels was done one (T2) and twelve (T3) months after the diabetes induction. The CG rats in T3 showed vesicles and dense bodies in the endothelial and pericytic cells; the same structures were observed in the DG at T2. The DG rats in T3 had even more and intense changes than the T2DG rats. The morphological evaluation indicates that the choroidal vessels are affected in diabetes and the disease accelerates degenerative processes in the rat choroidal vasculature.     

How informed is consent? Use of an information booklet in patients undergoing total hip replacement

For informed consent, patients must understand the risks and benefits of the proposed procedure. Fifty patients undergoing total hip replacement (THR) participated in an evaluation of a newly devised information booklet. Patients' understanding of the risks and benefits of THR was assessed using a questionnaire before and after they had read the booklet. Pre-booklet patients knew on average 2 benefits of THR, compared with 3 afterwards. Twenty-two patients initially identified no alternative treatment to THR. Those who knew an alternative stated on average 1 treatment compared with 2 in the post-booklet group. Fifteen patients identified no risks of THR initially, compared with two after reading the booklet. Initially patients reported 1 risk, versus 3 after reading the booklet. Forty-eight patients thought that the booklet increased their understanding of THR and its risks. Fourteen found it upsetting, but acceptable. Forty-six patients wished to keep the booklet.     

Energy Balance,Eating Disorder Risk,and Pathogenic Behaviors Among Athletic Trainers

ContextResearch exists on energy balances (EBs) and eating disorder (ED) risks in physically active populations and occupations by settings, but the EB and ED risk in athletic trainers (ATs) have not been investigated.ObjectiveTo assess ATs'' energy needs, including the macronutrient profile, and examine ED risk and pathogenic behavioral differences between sexes (men, women) and job statuses (part time or full time) and among settings (college or university, high school, nontraditional).DesignCross-sectional study.SettingFree living in job settings.Patients or Other ParticipantsAthletic trainers (n = 46; male part-time graduate assistant ATs = 12, male full-time ATs = 11, female part-time graduate assistant ATs = 11, female full-time ATs = 12) in the southeastern United States.Main Outcome Measure(s)Anthropometric measures (sex, age, height, weight, body composition), demographic characteristics (job status [full- or part-time AT], job setting [college/university, high school, nontraditional], years of AT experience, exercise background, alcohol use), resting metabolic rate, energy intake (EI), total daily energy expenditure (TDEE), EB, exercise energy expenditure, macronutrients (carbohydrates, protein, fats), the Eating Disorder Inventory-3, and the Eating Disorder Inventory-3 Symptom Checklist.ResultsThe majority of participants (84.8%, n = 39) had an ED risk, with 26.1% (n = 12) engaging in at least 1 pathogenic behavior, 50% (n = 23) in 2 pathogenic behaviors, and 10.8% (n = 5) in >2 pathogenic behaviors. Also, 82.6% of ATs (n = 38) presented in negative EB (EI < TDEE). Differences were found in resting metabolic rate for sex and job status (F_1,45 = 16.48, P = .001), EI (F_1,45 = 12.01, P = .001), TDEE (F_1,45 = 40.36, P < .001), and exercise energy expenditure (F_1,38 = 5.353, P = .026). No differences were present in EB for sex and job status (F_1,45 = 1.751, P = .193); χ² analysis revealed no significant relationship between ATs'' sex and EB (= 0.0, P = 1.00) and job status and EB ( = 2.42, P = .120). No significant relationship existed between Daily Reference Intakes recommendations for all macronutrients and sex or job status.ConclusionsThese athletic trainers experienced negative EB, similar to other professionals in high-demand occupations. Regardless of sex or job status, ATs had a high ED risk and participated in unhealthy pathogenic behaviors. The physical and mental concerns associated with these findings indicate a need for interventions targeted at ATs'' health behaviors.     

Pathogenicity of entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae to Ixodidae tick species Dermacentor variabilis, Rhipicephalus sanguineus, and Ixodes scapularis

Nymphal and adult ticks from three different tick species, Dermacentor variabilis Say, Ixodes scapularis Say, and Rhipicephalus sanguineus Latrielle, were treated with conidia and blastospores of the entomopathogenic fungi Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae Metschnikoff. Dose-response experiments indicated that a critical concentration of fungal spores is required for infection and mortality. Over a 28-d time course, fungal suspensions of either B. bassiana or M. anisopliae at 10(8) conidia/ml resulted in 50-70% mortality in adult I. scapularis and R. sanguineus, but <20% mortality in D. variabilis ticks. R. sanguineus nymphs were highly susceptible to both entomopathogenic fungi, displaying >60% mortality within 14 d postinfection and >90% mortality within 21-28 d postinfection. D. variabilis nymphs also were more susceptible than their corresponding adults, displaying mortalities ranging from 20 to 40% 28 d postinfection. I. scapularis nymphs, however, seemed to be slightly less susceptible than adults (45% mortality, 28 d postinfection). The addition of nutrients to fungal cell suspensions did not have any noticeable effects on mortality toward any of the tick species tested. Significant mortality against D. variabilis adults (approximately 65%) was noted only when B. bassiana fungal cells with growth media carryover were used as the inoculum against the ticks. Entomopathogenic fungi such as B. bassiana and M. anisopliae may have the potential for controlling populations of I. scapularis and R. sanguineus, and under certain conditions D. variabilis. Our results indicate that inoculum conditions can greatly affect successful virulence and subsequent mortality.     

To err is autonomic: error-related brain potentials, ANS activity, and post-error compensatory behavior

A two-component event-related brain potential consisting of an error-related negativity (ERN/Ne) and positivity (Pe) has been associated with response monitoring and error detection. Both the ERN and Pe have been source-localized to the anterior cingulate cortex (ACC)--a frontal structure implicated in both cognitive and affective processing, as well as autonomic nervous system (ANS) modulation. The current study sought to examine the relationships among the ERN, the Pe, two autonomic measures, and behavior. Electroencephalogram (EEG), heart rate (HR), and skin conductance (SC) were recorded while subjects performed a two-choice reaction-time task. In addition to the characteristic ERN-Pe complex, errors were associated with larger SCRs and greater HR deceleration. The ERN correlated with the number of errors, but was unrelated to ANS activity and compensatory behavior. Pe, on the other hand, was correlated significantly with SCR, and both SCR and Pe were significantly correlated with post-error slowing.     

Unusual proton exchange properties of Z-form poly[d(G-C)

Real-time solvent-exchange NMR has been used to study the proton exchange in Z-form poly[d(G-C)]. In 4.5 M NaCl the most slowly exchanging protons (about two orders of magnitude slower than in B-DNA) are identified as the guanine imino proton and the cytosine amino proton hydrogen bonded to the guanine carbonyl. Both protons exchange at the same rate and the exchange follows single-exponential kinetics and cannot be catalyzed, implying that the exchanges of the two protons both occur from the same transient solvent-exposed state. The exchange depends strongly on temperature and the activation energy for exchange (≈22 kcal/mol) is the same as the activation energy for the B → Z transition. The rate of proton exchange is identical with the B → Z transition rate, both measured in 4.5 M NaCl. The correlation between the B → Z kinetics and the proton exchange also extends to 3.25 M NaClO₄ solutions, in which both rates are 5 times faster. This unexpected parallelism between the B → Z transition kinetics and the Z exchange kinetics indicates that the rate-limiting steps in the two processes are similar.     

Topical Vancomycin Powder and Dilute Povidone-Iodine Lavage Reduce the Rate of Early Periprosthetic Joint Infection After Primary Total Knee Arthroplasty

BackgroundVancomycin powder and dilute povidone-iodine lavage (VIP) was introduced to reduce the incidence of periprosthetic joint infection (PJI) in high-risk total knee arthroplasty (TKA) patients. We hypothesize that VIP can reduce the incidence of early PJI in all primary TKA patients, regardless of preoperative risk.MethodsAn infection database of primary TKAs performed before a VIP protocol was implemented (January 2012-December 2013), during a time when only high-risk TKAs received VIP (January 2014-December 2015), and when all TKAs received VIP (January 2016-September 2019) at an urban, university-affiliated, not-for-profit orthopedic hospital was retrospectively reviewed to identify patients with PJI. Criteria used for diagnosis of PJI were the National Healthcare Safety Network and Musculoskeletal Infection Society guidelines.ResultsVIP reduced early primary TKA PJI incidence in both the high-risk and all-risk cohorts compared with the pre-VIP cohort by 44.6% and 56.4%, respectively (1.01% vs 0.56% vs 0.44%, P = .0088). In addition, after introducing VIP to all-risk TKA patients, compared with high-risk TKA patients, the relative risk of PJI dropped an additional 21.4%, but this finding did not reach statistical significance (0.56% vs 0.44%, P = .4212). There were no demographic differences between the 3 VIP PJI cohorts.ConclusionVIP is associated with a reduced early PJI incidence after primary TKA, regardless of preoperative risk. With the literature supporting its safety and cost-effectiveness, VIP is a value-based intervention, but given the nature of this historical cohort study, a multicenter randomized controlled trial is underway to definitively confirm its efficacy.