The coax monopole antenna: A flexible end-fed antenna for ultrahigh field transmit/receive arrays.

PURPOSE: The coax monopole antenna is presented for body imaging at 7 T. The antenna is fed at one end, eliminating the possibility of cable-coil coupling and simplifying cable routing. Additionally, its flexibility improves loading to the subject. METHODS: Like the coax dipole antenna, an interruption in the shield of the coaxial cable allows the current to extend to the outside of the shield, generating a B1 + field. Matching is achieved using a single inductor at the distal side, and a cable trap enforces the desired antenna length. Finite difference time domain simulations are employed to optimize the design parameters. Phantom measurements are conducted to determine the antenna's B1 + efficiency and to find the S-parameters in straight and bent positions. Eight-channel simulations and measurements are performed for prostate imaging. RESULTS: The optimal configuration is a length of 360 mm with a gap position of 40 mm. Simulation data show higher B1 + levels for the coax monopole (20% in the prostate), albeit with a 5% lower specific absorbance rate efficiency, compared to the fractionated dipole antenna. The S11 of the coax monopole exhibits remarkable robustness to loading changes. In vivo prostate imaging demonstrates B1 + levels of 10-14 µT with an input power of 8 × 800 W, which is comparable to the fractionated dipole antenna. High-quality images and acceptable coupling levels were achieved. CONCLUSION: The coax monopole is a novel, flexible antenna for body imaging at 7 T. Its simple design incorporates a single inductor at the distal side to achieve matching, and one-sided feeding greatly simplifies cable routing.

The relationship between the cholinergic mechanism of toxicity and oxidative stress in rats during subacute diazinon poisoning.

Diazinon is an organophosphate pesticide (OP) that has significant potential for accidental and intentional poisoning of wildlife, domestic animals and humans. The aim of the study is to investigate the correlation between cholinesterase activity and oxidative stress parameters in liver and diaphragm by continuous monitoring as a function of time during prolonged use of diazinon. Wistar rats were treated orally with diazinon (55 mg/kg/day): 7, 14, 21 and 28 days. At the end of each period, blood, liver and diaphragm were collected to examine cholinesterase activity and enzymatic/non-enzymatic oxidative stress parameters: superoxide dismutase 1 (SOD1), catalase (CAT), thiobarbituric acid substances (TBARS), protein carbonyl groups. In all four time periods, there was a significant change in acetylcholinesterase (AChE) in erythrocytes and butyrylcholinesterase (BuChE) in blood plasma, CAT in liver and diaphragm and SOD1 in diaphragm. Parameters significantly altered during the cholinergic crisis included: cholinesterases and TBARS in liver and diaphragm and partially SOD1 in liver. Protein carbonyl groups in liver and diaphragm were significantly altered outside the cholinergic crisis. In the liver, there was a very strong negative correlation between BuChE and TBARS in all four time periods and BuChE and CAT on day 7. In the diaphragm, a very strong negative correlation was found between AChE and TBARS at days 7 and 14, and a very strong positive correlation between AChE and SOD1 at days 14, 21 and 28. A better understanding of the relationship between cholinergic overstimulation and oxidative stress may help to better assess health status in prolonged OPs intoxication.

Major morbidity and mortality associated with delays to emergent surgery in children: a risk-adjusted analysis.

BACKGROUND: Delay of emergency surgery contributes to morbidity and mortality, and physiologic status affects outcomes of patients requiring emergent surgery. Our purpose was to determine whether delays to emergent surgery in children were associated with increased major morbidity or mortality in a risk-adjusted population. METHODS: We performed a retrospective review of class 1 (≤ 60 min to operating room) surgical procedures from July 11, 2011, to July 30, 2016, at BC Children's Hospital, Vancouver. Data sources included the operating room database, patient charts, American Society of Anesthesiologists classification, Neonatal Acute Physiology (SNAP II) and Pediatric Risk of Mortality (PRISM III) scores, time from booking to operating room and outcome. Patients were classified as being at low or high risk for death. We defined major morbidity as unintended loss of an organ, limb or function related to surgery, and delay to surgery as more than 60 minutes from booking to in room. We used the χ2 test for univariate analysis and logistic regression for multivariate analysis. RESULTS: There were 384 cases (367 patients), 223 high-risk and 161 low-risk. The median age was 4 years (range 0 d-18 yr). Overall, 184 cases (47.9%) were delayed. Major morbidity occurred in 94 cases (24.5%), and 28 patients (7.6%) (all in the high-risk group) died. The mean time to the operating room was 1.46 hours for patients with major morbidity/mortality and 1.17 hours for those without. After adjustment for risk level, multivariate analysis showed delay to surgery to be associated with 85% increased odds of morbidity and/or mortality (adjusted odds ratio 1.85, 95% confidence interval 1.20-2.94) compared to no delay. CONCLUSION: Delay to emergent surgery was associated with a significant increase in major morbidity and/or mortality. Children who require emergency surgery need their care prioritized by not only operating room teams but also hospitals and government; otherwise, they will continue to experience unintended consequences.

Novel materials in magnetic resonance imaging: high permittivity ceramics, metamaterials, metasurfaces and artificial dielectrics.

This article reviews recent developments in designing and testing new types of materials which can be: (i) placed around the body for in vivo imaging, (ii) be integrated into a conventional RF coil, or (iii) form the resonator itself. These materials can improve the quality of MRI scans for both in vivo and magnetic resonance microscopy applications. The methodological section covers the basic operation and design of two different types of materials, namely high permittivity materials constructed from ceramics and artificial dielectrics/metasurfaces formed by coupled conductive subunits, either in air or surrounded by dielectric material. Applications of high permittivity materials and metasurfaces placed next to the body to neuroimaging and extremity imaging at 7 T, body and neuroimaging at 3 T, and extremity imaging at 1.5 T are shown. Results using ceramic resonators for both high field in vivo imaging and magnetic resonance microscopy are also shown. The development of new materials to improve MR image quality remains an active area of research, but has not yet found significant use in clinical applications. This is mainly due to practical issues such as specific absorption rate modelling, accurate and reproducible placement, and acceptable size/weight of such materials. The most successful area has been simple "dielectric pads" for neuroimaging at 7 T which were initially developed somewhat as a stop-gap while parallel transmit technology was being developed, but have continued to be used at many sites. Some of these issues can potentially be overcome using much lighter metasurfaces and artificial dielectrics, which are just beginning to be assessed.

Evaluation of Interventions Addressing Timely Access to Surgical Care in Low-Income and Low-Middle-Income Countries as Outlined by the LANCET Commission 2030 Global Surgery Goals: A Systematic Review.

BACKGROUND: In 2015, the Lancet Commission on Global Surgery published six global surgery goals, one of which was to provide 80% of the world's population with timely access to the Bellwether Surgical procedures. Little is known about the prevalence or efficacy of subsequent interventions implemented in under-resourced countries to increase timely access to Bellwether surgical procedures. METHODS: A systematic review of articles and grey literature published in MEDLINE, Embase, Cochrane, CINAHL, and Web of Science databases was conducted. Two independent reviewers evaluated 1923 captured abstracts using explicit inclusion and exclusion criteria. Following a thematic analysis, two reviewers conducted data extraction on the eleven manuscripts included in the final review. RESULTS: The studied innovations, sparse in number, centred on improved educational resources, the development of orthopaedic devices, and models for assessing surgical access disparity. Eight papers were centred around timely access to caesarean sections, three around open fracture reduction, and three around laparotomy; all focused on adult populations. Five papers addressed innovations in West Africa, two in East Africa, two in South Asia, and one in Southeast Asia. Common outcome metrics were not used to assess improvements to timely surgical access. CONCLUSIONS: Few published interventions have been implemented since the publication of the 2015 Lancet Commission on Global Surgery goals that have or will longitudinally increase the availability of timely surgical access in Low and Middle-Income Countries (LMIC). Tangible outcome measures in existing literature are lacking. An up-scaling and wider adoption of successful strategies is necessary and possible.

A Global Survey of Patient and Caregiver Experiences Throughout Care for Developmental Dysplasia of the Hip.

BACKGROUND: Diagnosis and treatment for developmental dysplasia of the hip (DDH) varies greatly depending on condition severity, age at diagnosis, and professional opinion. Little is known about patient experiences across the globe. We aimed to characterize global patient and caregiver experiences during DDH care and to highlight patient-identified priorities. METHODS: We developed a cross-sectional survey in collaboration with 7 DDH outreach organizations. DDH patients and/or their caregivers (above 18 y old) were invited to complete an international online survey about their experiences. Participants were recruited through web media of all collaborating organizations. Data collection took place over 3 months. Descriptive statistics were used to analyze quantitative results. Qualitative content analysis was used to categorize open-ended responses. RESULTS: A total of 739 participants completed the survey, representing 638 (86.3%) parents/guardians of DDH patients, and 101 (13.7%) patients. Three hundred eighty-six (52.2%) participants received diagnosis by 3 months of age; mean age of diagnosis was 15.96 months (90% confidence interval=12.04, 19.91). Of 211 participants with family history of DDH, 68 (32.3%) did not receive DDH screening. Of 187 patients born breech, 82 (43.9%) did not receive DDH screening. In total, 36/94 (38.3%) participants with both family history and breech birth did not receive DDH screening. Most participants reported treatment (696/730, 95.3%), including bracing (n=461) surgery (n=364), and/or closed reduction (n=141). A total of 144 patients reported >1 surgery; 82 reported >3 surgeries. Participants reported a range of 1 to 400 visits to health care professionals for DDH care across 1 to 66 years. Lack of information and resources on treatment practicalities and timelines, along with emotional burden of diagnosis, were greatest challenges reported. CONCLUSION: Results demonstrate that DDH diagnosis and treatment can pose significant burden on patients and caregivers. Reliable public information is needed to support those affected. Global educational efforts are needed to raise awareness of DDH risk factors, signs, and symptoms among care providers, to increase awareness and improve identification, screening, and monitoring of at-risk children.

A flexible five-channel shielded-coaxial-cable (SCC) transceive neck coil for high-resolution carotid imaging at 7T.

PURPOSE: Imaging the carotid arteries at 7T ideally requires a flexible multichannel array that allows B1-shimming and conforms to different neck sizes. The major challenge is to minimize coupling between closely spaced coils and to make the coupling relatively insensitive to loading conditions. METHODS: We have designed a five-channel flexible transceive array composed of shielded-coaxial-cable coils placed on the anterior part of the neck and conforming to the anatomy. In vivo imaging of the carotid arteries in three subjects has been performed. RESULTS: The measured noise correlation matrices show the decoupling level between the individual elements to be -12.5 dB and better. Anatomical localizer imaging of the carotids shows both carotids in every subject well visualized after B1-shimming. In vivo black-blood, carotid images were acquired with very high in-plane spatial resolution (0.25 × 0.25 mm2 ) with clear depiction of the vessel walls. CONCLUSIONS: The flexibility of the proposed coil has been demonstrated by imaging subjects with different neck circumferences. To the best of our knowledge, the in-plane resolution of 0.25 × 0.25 mm2 is the highest reported at 7T.

Shielded-coaxial-cable coils as receive and transceive array elements for 7T human MRI.

PURPOSE: To investigate the use of shielded-coaxial-cable (SCC) coils as elements for multi-channel receive-only and transceive arrays for 7T human MRI and to compare their performance with equivalently sized conventional loop coils. METHODS: The SCC coil element consists of a coaxial loop with interrupted central conductor at the feed-point side and an interrupted shield at the opposite point. Inter-element decoupling, transmit efficiency, and sample heating were compared with results from conventional capacitively segmented loop coils. Three multichannel arrays (a 4-channel receive-only array and 8- and 5-channel transceive arrays) were constructed. Their inter-element decoupling was characterized via measured noise correlation matrices and additionally under different flexing conditions of the coils. Thermal measurements were performed and in vivo images were acquired. RESULTS: The measured and simulated B1+ maps of both SCC and conventional loops were very similar. For all the arrays constructed, the inter-element decoupling was much greater for the SCC elements than the conventional ones. Even under high degrees of flexion, the coupling coefficients were lower than -10 dB, with a much smaller frequency shift than for the conventional coils. CONCLUSION: Arrays constructed from SCC elements are mechanically flexible and much less sensitive to changes of the coil shape from circular to elongated than arrays constructed from conventional loop coils, which makes them suitable for construction of size adjustable arrays.

Design and characterization of an eight-element passively fed meander-dipole array with improved specific absorption rate efficiency for 7 T body imaging.

OBJECTIVE: To evaluate the transmit efficiency and specific absorption rate (SAR) efficiency of a new eight-element passively fed meander-dipole antenna array designed for body MRI at 7 T, and to compare these values with a conventional directly fed meander-dipole array. METHODS: The main radiating element of the passively fed dipole is printed on one side of a dielectric substrate and is capacitively coupled to a shorter feeding element (connected to the coaxial cable) printed on the opposite side of the substrate. The transmit (B1+ ) field and SAR were simulated on a phantom and on a human voxel model for both a passively fed and a directly fed single element. Two eight-channel arrays containing, respectively, directly and passively fed meander dipoles were then simulated, and experimental B1+ maps and T2 -weighted spin echo images of the prostate were obtained in vivo for four healthy volunteers. RESULTS: In simulations, the mean transmit efficiency (B1+ per square root input power) value in the prostate was ~ 12.5% lower, and the maximum 10 g average SAR was 44% lower for the array containing passively fed dipoles, resulting in ~ 15% higher SAR efficiency for the passively fed array. In vivo RF-shimmed turbo spin echo images were acquired from both arrays, and showed image SNRs within 5% of one another. CONCLUSION: A passive-feeding network for meander-dipole antennas has been shown to be a simple method to increase the SAR efficiency of a multi-element array used for body imaging at high fields. We hypothesize that the main reason for the increase in SAR efficiency is the storage of the strong conservative electric field in the dielectric between the feeding element and the radiating element of the dipole. The passive-feeding approach can be generalized to other dipole geometries and configurations.

Influence of aging on germinal centre reaction and antibody response to inactivated influenza virus antigens in mice: sex-based differences.

The study examined sex-specificities in age-related changes in BALB/c mice IgG antibody responses to immunisation with trivalent inactivated split-virus influenza bulk. Aging diminished the total serum IgG antibody responses to H1N1 and H3N2 and B influenza virus antigens in mice of both sexes, but they remained greater in aged females. This sex difference in aged mice correlated with the greater post-immunisation increase in the frequency of spleen germinal centre (GC) B cells and more favourable T follicular regulatory (Tfr)/GC B cell ratio, as Tfr cells are suggested to control antibody production through suppression of glycolysis. The greater post-immunisation GC B cell response in aged females compared with males correlated with the greater proliferation of B cells and CD4+ cells in splenocyte cultures from aged females restimulated with inactivated split-virus influenza from the bulk. To support the greater post-immunisation increase in the frequency GC B cell in aged females was more favourable Tfr/T follicular helper (Tfh) cell ratio. Additionally, compared with aged males, in age-matched females the greater avidity of serum IgG antibodies was found. However, in aged females IgG2a/IgG1 antibody ratio, reflecting spleen Th1/Th2 cytokine balance, was shifted towards IgG1 when compared with age-matched male mice. This shift was ascribed to a more prominent decline in the titres of functionally important IgG2a antibodies in females with aging. The study suggest that biological sex should be considered as a variable in designing strategies to manipulate with immune outcome of immunisation in aged animals, and possibly, at very long distance, humans.

Sex bias in mouse humoral immune response to influenza vaccine depends on the vaccine type.

The study explored influence of biological sex on development of humoral immune response to seasonal trivalent whole inactivated virus (WIV) and split virus (SV) influenza vaccines in outbred Swiss mouse model. To this end, mice of both sexes were immunized with WIV (WIV mice) and SV vaccines (SV mice) and examined for specific antibody response. Irrespective of sex, total IgG and neutralizing antibody responses to distinct virus strains were weaker in SV than in WIV mice. In WIV mice of both sexes, irrespective of strain specificity, IgG isotype response was dominated by IgG2a antibodies, while in SV mice nearly equal representation of IgG2a and IgG1 antibodies was found. The analyses of sex differences showed higher titers of H1N1-specific and both H1N1- and H3N2-specific total IgG and neutralizing antibodies in female WIV and SV mice, respectively. Additionally, sexual dimorphism in IgG subclass profile depended on vaccine type. Specifically, compared with males, in females WIV shifted IgG2a/IgG1 antibody ratio towards IgG2a isotype on the account of weaker IgG1 response, whereas in SV mice, irrespective of virus strain, IgG2a and IgG1 isotypes were equally represented in both sexes. These findings indicate the vaccine type-dependent sex bias in antibody response to inactivated influenza vaccines.

Single-channel, box-shaped, monopole-type antenna for B1+ field manipulation in conjunction with the traveling-wave concept in 9.4 T MRI.

OBJECT: We have developed a single-channel, box-shaped, monopole-type antenna which, if used in two different configurations, excites complementary B1+ field distributions in the traveling-wave setup. MATERIALS AND METHODS: A new monopole-type, single-channel antenna for RF excitation in 9.4 T magnetic resonance imaging is proposed. The antenna is entirely made of copper without lumped elements. Two complementary B1+ field distributions of two different antenna configurations were measured and combined as a root sum of squares. B1+ field inhomogeneity of the combined maps was calculated and compared with published results. RESULTS: By combining B1+ field distributions generated by two antenna configurations, a "no voids" pattern was achieved for the entire upper brain. B1+ inhomogeneity of approximately 20 % was achieved for sagittal and transverse slices; it was <24 % for coronal slices. The results were comparable with those from CP, with "no voids" in slice B1+ inhomogeneity of multichannel loop arrays. The efficiency of the proposed antenna was lower than that of a multichannel array but comparable with that of a patch antenna. CONCLUSION: The proposed single-channel antenna is a promising candidate for traveling-wave brain imaging. It can be combined with the time-interleaved acquisition of modes (TIAMO) concept if reconfigurability is obtained with a single-antenna element.

Brain and liver fatty acid composition changes upon consumption of Lactobacillus rhamnosus LA68.

Recent reports suggest that the metabolic activity of the enteric microbiota may influence the fatty acid composition of the host tissue. There are many studies dealing with the influence of lactobacilli on various pathological conditions, and some of the effects are strain-specific. This study was designed to test the effects of a particular Lactobacillus strain, Lactobacillus rhamnosus LA68 on fatty acid composition of the liver and the brain of C57BL/6 mice in the absence of an underlying pathological condition. Female mice were supplemented with live L. rhamnosus LA68 bacteria for the duration of 1 month. Serum biochemistry was analyzed and liver and brain fatty acid composition was assessed by gas-liquid chromatography. Significant changes in liver and brain fatty acid composition were detected. In the liver tissue we detected an increase in palmitoleic acid (p = 0.038), while in the brain compartment we found an increase in palmitic (p = 0.042), stearic (p = 0.017), arachidonic acid (p = 0.009) and docosahexaenoic acid (p = 0.004) for control versus experimental group. These results show discrete changes caused by LA68 strain consumption. Even short duration of administration of LA68 influences the fatty acid composition of the host which adds to the existing knowledge about Lactobacillus host interaction, and adds to the growing knowledge of metabolic intervention possibilities.

Infection-induced autoantibodies and pregnancy related pathology: an animal model.

In addition to being the main cause of mortality worldwide, bacterial and viral infections can be the cause of autoimmune and pregnancy disorders as well. The production of autoantibodies during infection can be explained by various mechanisms, including molecular mimicry, bystander cell activation and epitope spreading. Conversely, bacterial and viral infections during pregnancy are especially dangerous for the fetus. It is documented that infection-induced inflammatory processes mediated by Toll-like receptors (TLR) represent the main cause of preterm labour. We used two crucial bacterial components and TLR ligands, namely peptidoglycan and lipopolysaccharide, to stimulate BALB/c mice before immunisation with tetanus toxoid. Tetanus toxoid is an inactive form of the toxin produced by bacterium Clostridium tetani and shares structural similarity with plasma protein ß2-glycoprotein I. Treatment with peptidoglycan and lipopolysaccharide in combination with tetanus toxoid induced the production of pathological autoantibodies, different fluctuations in natural autoantibodies and different types of reproductive pathology in treated animals, with peptidoglycan treatment being more deleterious. We propose that the production of pathological autoantibodies, TLR activation and changes in natural autoantibodies play crucial roles in infection-induced reproductive pathology in our animal model.

Effects of Lactobacillus rhamnosus LA68 on the immune system of C57BL/6 mice upon oral administration.

Probiotic bacteria have been used in human nutrition for centuries and are now attracting more attention. In order to examine the immunological aspects of probiotic consumption, Lactobacillus rhamnosus LA68 was orally administrated using gavage to healthy C57BL/6 mice. After one month splenocytes were isolated, and analysed by flow cytometry. The magnitude of splenocyte proliferation upon stimulation with lipopolysaccharide and peptidoglycan and cytokine levels (IFN-γ, IL-6, IL-10 and IL-17) was assessed. Cytokine levels in the serum were also analysed. Oral application of strain LA68 leads to a significant decrease of CD3+, CD25+ and CD19+ cells, and an increase of CD11b+ and CD16/CD32+ positive cell populations in the mouse spleen. Increased sensitivity to stimulation through proliferation and IL-6 secretion was detected. Increased serum IFN-γ and decreased IL-10 levels were found. Our results show increased responsiveness of splenocytes, activation of the Th1 type of immune response, and a shift of leucocyte populations towards monocyte/granulocyte populations.

Twisted pair transmission line coil - a flexible, self-decoupled and robust element for 7 T MRI.

OBJECTIVE: This study evaluates the performance of a twisted pair transmission line coil as a transceive element for 7 T MRI in terms of physical flexibility, robustness to shape deformations, and interelement decoupling. METHODS: Each coil element was created by shaping a twisted pair of wires into a circle. One wire was interrupted at the top, while the other was interrupted at the bottom, and connected to the matching circuit. Electromagnetic simulations were conducted to determine the optimal number of twists per length (in terms of B1+ field efficiency, SAR efficiency, sensitivity to elongation, and interelement decoupling properties) and for investigating the fundamental operational principle of the coil through fields streamline visualisation. A comparison between the twisted pair coil and a conventional loop coil in terms of B1+ fields, maxSAR10g, and stability of S11 when the coil was deformed was performed. Experimentally measured interelement coupling between individual elements of multichannel arrays was also investigated. RESULTS: Increasing the number of twists per length resulted in a more physically robust coil. Poynting vector streamline visualisation showed that the twisted pair coil concentrated most of the energy in the near field. The twisted pair coil exhibited comparable B1+ fields and improved maxSAR10g to the conventional coil but demonstrated exceptional stability with respect to coil deformation and a strong self-decoupling nature when placed in an array configuration. DISCUSSION: The findings highlight the robustness of the twisted pair coil, showcasing its stability under shape variations. This coil holds great potential as a flexible RF coil for various imaging applications using multiple-element arrays, benefiting from its inherent decoupling.

B-cell response to seasonal influenza vaccine in mice is amenable to pharmacological modulation through ß-adrenoceptor.

AIMS: Given that deprivation of noradrenaline acting on lymphocytes through ß-adrenoceptor influences antibody response, the effects of propranolol treatment beginning two days before immunization with quadrivalent inactivated influenza vaccine (QIV) on IgG response and underlying cellular molecular mechanism in mice were investigated. MAIN METHODS: Twenty-one days post-immunization the total QIV antigen-specific IgG titer and IgG subclass titers in sera were determined using ELISA. Additionally, the total counts of germinal centre (GC) B cells, T follicular helper (Tfh) and T follicular regulatory (Tfr) cells in draining lymph nodes (dLNs) and spleens, in vitro proliferation of interacting B cells and Th cells and IL-21 synthesis in Th cells in response to QIV antigens and/or mitogen were attested using flow cytometry analysis. In QIV antigen-stimulated dLN cell and splenocyte cultures were also measured concentrations of INF-γ and IL-4, cytokines upregulating IgG2a and IgG1 synthesis, respectively. KEY FINDINGS: Propranolol decreased the total QIV antigen-specific IgG titer. This correlated with lower GC B cell count and the shift in Tfr/Tfh cell and Tfr/GC B cell ratio towards Tfr in propranolol-treated mice compared with controls. Consistently, QIV antigen-stimulated proliferation of B cells and Th cells from propranolol-treated mice in vitro was impaired. This correlated with the lower frequency of QIV antigen-specific IL-21-producing cells among Th cells. Additionally, in propranolol-treated mice, in accordance with the changes in INF-γ/IL-4 ratio in dLN cell/splenocyte cultures, serum IgG2a/IgG1 ratio was shifted towards IgG1 reflecting decreased IgG2a response. SIGNIFICANCE: The study indicates that chronic propranolol treatment may impair response to QIV.

Age and gender associated changes in immunoglobulin subclass levels specific to S. pneumoniae, serotype 1.

S. pneumoniae is an important human pathogen which has a polysaccharide capsule with virulent properties. This work aims to estimate the titres of S. pneumoniae specific IgG and IgA isotypes, with respect to age and sex. An in-house whole bacterial cell ELISA was used for the determination of relative levels and endpoint titres of IgG subclasses and IgA1 subclass specific for S. pneumoniae serogroup 1, and to quantify specific IgG1 and IgG2 levels. Significantly lower anti-pneumococcus IgG1 titres were found in older individuals, which was more pronounced in men. Lower IgG2 titres were detected in men over 50 years of age, in comparison to women under 50 years of age. The levels of IgG3 and IgG4 did not differ between different sex and age groups. Lower IgA1 levels were detected in male individuals in both age groups in comparison to females under 50 years of age. The levels of IgG1 showed a moderate correlation with IgG4 in younger individuals of both sexes (r = 0.61 in men and 0.63 in women) which was not noted in the older age group. We highlight the deficiency in humoral immunity in older people, especially male and suggest immunization of this population with pneumococcal vaccines.

Comparison of Enzyme-Linked Lectin Sorbent Assay and Flow Cytometry for Profiling Microbial Glycans.

The surface of microorganisms is covered with carbohydrates, which makes them unique, self-sustaining glycan probes. Lectins are able to bind to these probes, and this interaction can be exploited for selecting microorganisms or novel lectins. To examine lectin-microorganism interactions, we have previously developed an enzyme-linked lectin sorbent assay (ELLSA) with whole bacterial cells. To further test the validity of this methodology, here we compare it with flow cytometry. For this purpose, we used biotinylated recombinantly produced lectin from Musa acuminata (BanLec), this lectin's recombinantly produced chimera with green fluorescent protein (BanLec-eGFP) and a lectin from Ricinus communis (RCA120), both biotinylated and FITC labeled. Parallel testing showed equivalent results for the two methods, in terms of the presence or absence of binding, with signal intensity yielding high Pearson correlation coefficient of 0.8 for BanLec and 0.95 for RCA120. The ELLSA method demonstrated multiple advantages, such as reliability and convenience for high-throughput analysis; it also required less lectin and yielded more consistent results. As such, ELLSA proved to be a useful tool for profiling microbial glycan structures or testing novel lectins.