A cloned antigen for serological diagnosis of Wuchereria bancrofti microfilaremia with daytime blood samples.

By differentially screening an adult Brugia malayi cDNA library with sera from microfilaremic and amicrofilaremic donors infected with Wuchereria bancrofti, we have identified a novel parasite antigen denoted SXP-1. Recombinant SXP-1 filarial antigen is preferentially recognized by sera from microfilaremic persons with bancroftian filariasis and from skin snip-positive patients with onchocerciasis. Antibodies to SXP-1 are restricted to the IgG4 subclass and gradually decline after treatment with diethylcarbamazine. These findings indicate that it may be possible to replace microscopic examination of night blood films with a serological test designed to detect antibodies to a mix of SXP-1 and other suitable antigens for the diagnosis of microfilaremia due to bancroftian filariasis.     

Investigation of the binding site of mouse IgG subclasses to homologous peritoneal macrophages.

The binding of mouse myeloma IgG1, IgG2a, IgG2b, IgG1 Fc, IgG2b Fc and a pepsin produced C-terminal subfragment of IgG1 Fc and IgG2b Fc (provisionally identified as pFc') to mouse peritoneal macrophages was investigated. The high affinity cytophilic antibodies belonged to IgG2 subclasses and the binding site of these antibodies was located in the CH3 homology region.     

Antibody and memory B cell responses to the dengue virus NS1 antigen in individuals with varying severity of past infection

To further understand the role of NS1-specific antibodies (Abs) in disease pathogenesis, we compared neutralizing antibody levels (Nabs), NS1-Ab levels, IgG antibody subclass profiles and NS1-specific memory B-cell responses (Bmems) in individuals, with varying severity of past dengue. Nabs (Neut50 titres) were assessed using the Foci Reduction Neutralization Test (FRNT) and in-house ELISAs were used to assess NS1-Abs and NS1-Ab subclasses for all four DENV serotypes in individuals with past DF (n = 22), those with past DHF (n = 14) and seronegative (SN) individuals (n = 7). B-cell ELISpot assays were used to assess NS1-specific Bmem responses. 15/22 (68.18%) individuals with past DF and 9/14 (64.29%) individuals with past DHF had heterotypic infections. Neut50 titres were found to be significantly higher for DENV1 than DENV2 (p = 0.0006) and DENV4 (p = 0.0127), in those with past DHF, whereas there was no significant difference seen in titres for different DENV serotypes in those with past DF. Overall NS1-Ab to all serotypes and NS1-specific IgG1 responses for DENV1, 2 and 4 serotypes were significantly higher in those with past DHF than individuals with past DF. Those with past DHF also had higher IgG1 than IgG3 for DENV1 and DENV3, whereas no differences were seen in those with past DF. Over 50% of those with past DF or DHF had NS1-specific Bmem responses to >2 DENV serotypes. There was no difference in the frequency of Bmem responses to any of the DENV serotypes between individuals with past DF and DHF. Although the frequency of Bmem responses to DENV1 correlated with DENV1-specific NS1-Abs levels (Spearman r = 0.35, p = 0.02), there was no correlation with other DENV serotypes. We found that those with past DF had broadly cross-reactive Nabs, while those with past DHF had higher NS1-Ab responses possibly with a different functionality profile than those with past DF. Therefore, it would be important to further evaluate the functionality of NS1-specific antibody and Bmem responses to find out the type of antibody repertoire that is associated with protection against severe disease.     

Asynchronous Testing of 2 Specimen-Diversion Devices to Reduce Blood Culture Contamination: A Single-Site Product Supply Quality Improvement Project

ObjectiveBlood culture contamination above the national threshold has been a consistent clinical issue in the ED setting. Two commercially available devices were examined that divert an initial small volume of the specimen before the collection of blood culture to reduce skin contamination.MethodsProspectively, 2 different blood culture–diversion devices were made available in the unit supplies to ED clinicians at a single site during 2 different periods of time as a follow-up strategy to an ongoing quality improvement project. Blood samples were collected in the emergency department over a period of 16 months. A retrospective record review study was conducted comparing the use of the 2 specimen-diversion devices with no device (control group) for blood culture contamination rates. The main outcome of monthly blood culture contamination per device was tested using a Bayesian Poisson multilevel regression model.ResultsA total of 4030 blood samples were collected and analyzed from November 2017 to February 2019. The model estimated that the mean incidence of contaminated blood draws in the device A group was 0.29 (0.14-0.55) times the incidence of contaminated draws in the control group. The mean incidence of contaminated blood draws in the device B group was 0.23 (0.13-0.37) times the incidence of contaminated draws in the control group, suggesting that initial-diversion methods reduced blood culture contamination.ConclusionInitial specimen–diversion devices supplement present standard phlebotomy protocols to bring down the blood culture contamination rate.     

MRI confirms loss of blood–brain barrier integrity in a mouse model of disseminated candidiasis

Disseminated candidiasis primarily targets the kidneys and brain in mice and humans. Damage to these critical organs leads to the high mortality associated with such infections, and invasion across the blood–brain barrier can result in fungal meningoencephalitis. Candida albicans can penetrate a brain endothelial cell barrier in vitro through transcellular migration, but this mechanism has not been confirmed in vivo. MRI using the extracellular vascular contrast agent gadolinium diethylenetriaminepentaacetic acid demonstrated that integrity of the blood–brain barrier is lost during C. albicans invasion. Intravital two‐photon laser scanning microscopy was used to provide the first real‐time demonstration of C. albicans colonizing the living brain, where both yeast and filamentous forms of the pathogen were found. Furthermore, we adapted a previously described method utilizing MRI to monitor inflammatory cell recruitment into infected tissues in mice. Macrophages and other phagocytes were visualized in kidney and brain by the administration of ultrasmall iron oxide particles. In addition to obtaining new insights into the passage of C. albicans across the brain microvasculature, these imaging methods provide useful tools to study further the pathogenesis of C. albicans infections, to define the roles of Candida virulence genes in kidney versus brain infection and to assess new therapeutic measures for drug development. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Asymptomatic human carriers of Leishmania chagasi

In Brazil, programs based on elimination of infected dogs have not curtailed the spread of visceral leishmaniasis (VL), suggesting that other reservoirs of infection exist. Persons with active VL can infect the sand fly vector, but in endemic areas, persons with asymptomatic infections, whose infectivity to sand flies is unknown, are far more numerous. In this study, a polymerase chain reaction-based assay detected kinetoplast DNA of Leishmania chagasi in the blood of eight of 108 asymptomatic persons living with patients with recently diagnosed VL. These eight persons had low or unmeasurable levels of IgG antibodies to Leishmania, demonstrating the insensitivity of serology for subclinical infection. All eight persons had positive leishmanin skin test results, as did 70% of persons living in households of persons with active VL. Even if a small proportion of such asymptomatic persons are infective to sand flies, they represent a formidable reservoir of infection in endemic areas.     

Epidemiology of Chronic Kidney Disease,With Special Emphasis on Chronic Kidney Disease of Uncertain Etiology,in the North Central Region of Sri Lanka

Background

The aim of the study was to identify the epidemiology of chronic kidney disease of uncertain etiology in Sri Lanka.

Methods

A cross-sectional study was carried out by analyzing health statistics, and three cohort studies were conducted (n = 15 630, 3996, and 2809) to analyze the demographic information, age-specific prevalence, etiology, and stage of presentation. We screened 7604 individuals for chronic kidney disease of uncertain etiology.

Results

The results showed that the male:female ratio was 2.4:1, the mean age of patients was 54.7 ± 8 years, 92% of the patients were farmers, and 93% consumed water from shallow dug wells. Familial occurrence was common (36%). The prevalence of chronic kidney disease in different age groups was 3% in those aged 30–40 years; 7% in those aged 41–50 years, 20% in those aged 51–60 years, and 29% in those older than 60 years. Chronic kidney disease of uncertain etiology was diagnosed in 70.2% of patients, while 15.7% and 9.6% were due to hypertension and diabetic mellitus, respectively. The majority of patients were stage 4 (40%) at first presentation, while 31.8% were stage 3 and 24.5% were stage 5. Stage 1 and 2 presentation accounted for only 3.4%.

Conclusions

Low prevalence of CKDU was noticed (1.5%) among those who consumed water from natural springs. Prevalence was highest among males, rice farming communities, and those presenting at later disease stages.Key words: chronic kidney disease, uncertain etiology, epidemiology, North Central Province, male farmers, natural spring water     

Humans respond predominantly with IgM immunoglobulin to the species-specific glycolipid of Mycobacterium leprae

The immunoglobulin classes of the antibody response to the species-specific phenolic glycolipid antigen of Mycobacterium leprae have been characterized for serum specimens from 78 patients with leprosy. These patients included the entire clinical spectrum from paucibacillary to multibacillary disease, including polar tuberculoid (TT; 11 patients), borderline tuberculoid (BT; 15), borderline (BB; 17), borderline lepromatous (BL; 13), and lepromatous (LL; 22)--clinical classifications according to Ridley-Jopling criteria. In each patient group, the levels of IgM antibody to phenolic glycolipid were significantly higher than levels of IgG or IgA. Inhibition experiments with purified antigen showed that antibodies to the phenolic glycolipid dominated the human IgM antibody response to the surface of M. leprae.     

Morphological analysis of cementoenamel junction in premolars of Sri Lankans

Anatomical Science International - Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important...