Prevalence of Tachydysrhythmia in Patients with Chronic Obstructive Pulmonary Disorder Exacerbation in Emergency Department; a Cross-Sectional Study

مقدمه: ببیماران مبتلا به بیماری انسدادی مزمن ریه به دلایل متفاوتی نظیر هیپوکسی، هیپرکاپنی، اسیدوز تنفسی، آلکالوز تنفسی و متابولیک، هیپوکالمی، بیماری ایسکمیک  قلبی و کورپولمونل و همچنین مصرف داروهایی نظیر تئوفیلین و بتا آگونیستها در خطر بروز تاکی دیس ریتمی هستند. مطالعه حاضر با هدف بررسی میزان شیوع انواع تاکی دیس ریتمی در حمله حاد این بیماری طراحی شده است. روش کار: در این مطالعه مقطعی، بیمارانی که با تشخیص حمله حاد بیماری مزمن انسدادی ریه به بخش اورژانس مراجعه کرده بودند از جهت شیوع تاکی دیس ریتمی در نوار قلبی بدو ورود و توزیع آن بر اساس سن، جنس، سابقه بیماری زمینه ای، سابقه مصرف مواد و سیگار، سابقه بستری قبلی و مرگ و میر مورد مطالعه قرار گرفت. داده ها با نرم افزار آماری SPSS-21 آنالیز شد و 05/0 >  p به عنوان سطح معنی داری در نظر گرفته شد. يافته ها: 292 بیمار با میانگین سنی 11/12 ± 35/67 سال مورد ارزیابی قرار گرفتند (6/72 درصد مرد). شیوع دیس ریتمی معادل 138 بیمار (3/47 درصد) بود. ریتم سینوسی نرمال و تاکی کاردی سینوسی به ترتیب با فراوانی 7/52 و 6/35 درصدی، شایعترین ریتم های زمینه ای بودند. شیوع تاکی دیس ریتمی ها به طور معنی داری در بیماران با سابقه مصرف مواد مخدر (049/0 = p)، مصرف سیگار (011/0 = p) و دارای بیماری زمینه ای (017/0 = p) بالاتر بود و از نظر سنی (240/0 = p)، جنسی (062/0 = p) و وجود سابقه بستری قبلی (159/0 = p) تفاوتی در این خصوص روئیت نشد. در نهایت (7/93 درصد) 268 بیمار از بخش اورژانس ترخیص شدند و 18 نفر (3/6 درصد) مردند. شیوع تاکی دیس ریتمی ها در فوت شدگان 78/77 درصد در مقابل 78/44 درصد در بیماران ترخیص شده بود (007/0 = p). نتيجه گيری: بر اساس یافته ها، شیوع کلی تاکی دیس ریتمی در بیماران مبتلا به حمله حاد بیماری مزمن انسدادی ریه در مطالعه حاضر معادل 3/47 درصد بود. شایع ترین تاکی دیس ریتمی ها به ترتیب عبارت بودند از تاکی کاردی سینوسی، فیبریلاسیون دهلیزی، تاکی کاردی دهلیزی چند مرکزی و ریتم ایدیوجانکشنال. شیوع تاکی دیس ریتمی در افرادی فوت شده، با سابقه مصرف سیگار و مواد مخدر و همچنین دارای بیماری زمینه ای به طور معنی داری بالاتر بود.Introduction: Patients with chronic obstructive pulmonary disorder (COPD) are at risk of developing tahcydysrhythmia due to various reasons such as hypoxia, hypercapnia, respiratory acidosis, respiratory and metabolic alkalosis, hypokalemia, ischemic cardiac diseases, and cor-pulmonale as well as using drugs such as theophylline and beta-agonists. The present study was designed with the aim of evaluating the prevalence of various types of tachydysrhythmia in acute exacerbation of COPD. Methods: In this cross-sectional study, patients presenting to emergency department (ED) who were diagnosed with acute COPD exacerbation were evaluated regarding tachydysrhythmia prevalence in their electrocardiogram (ECG) on admission and its distribution based on age, sex, history of underlying illness, history of addiction or smoking, previous hospitalization, and mortality. Data were analyzed using SPSS 21 statistical software and p < 0.05 was considered as significance level. Results: 292 patients with the mean age of 67.35 ± 12.11 years were evaluated (72.6% male). Prevalence of dysrhythmia was 138 patients (47.3%). Normal sinuous rhythm and sinus tachycardia were the most common underlying rhythms with 52.7% and 35.6% prevalence, respectively. Prevalence of tachydysrhythmia was significantly higher in patients with a history of drug abuse (p = 0.049), smokers (p = 0.011), and those with an underlying disease (p = 0.017).  Yet, no difference was detected based on age (p = 0.240), sex (p = 0.062) and previous hospitalization (p = 0.159) in this regard. Finally, 268 (93.7%) patients were discharged from ED and 18 (6.3%) died. Prevalence of tachydysrhythmia in those who died was 77.78% compared with 44.78% in those who were discharged (p = 0.007). Conclusion: Based on the findings, overall prevalence of tachydysrhythmia in patients with COPD was 47.3% in the current study. The most common tachydysrhythmias were sinuous tachycardia, atrial fibrillation, multifocal atrial tachycardia, and idiojunctional rhythm. The prevalence of tachydysrhythmia was significantly higher in those who died, had a history of smoking and drug abuse, and those with an underlying disease.

Rapid Identification of Malaria Vaccine Candidates Based on α-Helical Coiled Coil Protein Motif

To identify malaria antigens for vaccine development, we selected α-helical coiled coil domains of proteins predicted to be present in the parasite erythrocytic stage. The corresponding synthetic peptides are expected to mimic structurally “native” epitopes. Indeed the 95 chemically synthesized peptides were all specifically recognized by human immune sera, though at various prevalence. Peptide specific antibodies were obtained both by affinity-purification from malaria immune sera and by immunization of mice. These antibodies did not show significant cross reactions, i.e., they were specific for the original peptide, reacted with native parasite proteins in infected erythrocytes and several were active in inhibiting in vitro parasite growth. Circular dichroism studies indicated that the selected peptides assumed partial or high α-helical content. Thus, we demonstrate that the bioinformatics/chemical synthesis approach described here can lead to the rapid identification of molecules which target biologically active antibodies, thus identifying suitable vaccine candidates. This strategy can be, in principle, extended to vaccine discovery in a wide range of other pathogens

Evaluation of immunoglobulin purification methods and their impact on quality and yield of antigen-specific antibodies

<p>Abstract</p> <p>Background</p> <p>Antibodies are the main effectors against malaria blood-stage parasites. Evaluation of functional activities in immune sera from Phase 2a/b vaccine trials may provide invaluable information in the search for immune correlates of protection. However, the presence of anti-malarial-drugs, improper collection/storage conditions or concomitant immune responses against other pathogens can contribute to non-specific anti-parasite activities when the sera/plasma are tested <it>in vitro</it>. Purification of immunoglobulin is a standard approach for reducing such non-specific background activities, but the purification method itself can alter the quality and yield of recovered Ag-specific antibodies.</p> <p>Methods</p> <p>To address this concern, various immunoglobulin (Ig) purification methods (protein G Sepharose, protein A/G Sepharose, polyethylene glycol and caprylic acid-ammonium sulphate precipitation) were evaluated for their impact on the quality, quantity and functional activity of purified rabbit and human Igs. The recovered Igs were analysed for yield and purity by SDS-PAGE, for quality by Ag-specific ELISAs (determining changes in titer, avidity and isotype distribution) and for functional activity by <it>in vitro </it>parasite growth inhibition assay (GIA).</p> <p>Results</p> <p>This comparison demonstrated that overall polyethylene glycol purification of human serum/plasma samples and protein G Sepharose purification of rabbit sera are optimal for recovering functional Ag-specific antibodies.</p> <p>Conclusion</p> <p>Consequently, critical consideration of the purification method is required to avoid selecting non-representative populations of recovered Ig, which could influence interpretations of vaccine efficacy, or affect the search for immune correlates of protection.</p

Pre-Clinical Assessment of Novel Multivalent MSP3 Malaria Vaccine Constructs

BACKGROUND: MSP3 has been shown to induce protection against malaria in African children. The characterization of a family of Plasmodium falciparum merozoite surface protein 3 (MSP3) antigens sharing a similar structural organization, simultaneously expressed on the merozoite surface and targeted by a cross-reactive network of protective antibodies, is intriguing and offers new perspectives for the development of subunit vaccines against malaria. METHODS: Eight recombinant polyproteins containing carefully selected regions of this family covalently linked in different combinations were all efficiently produced in Escherichia coli. The polyproteins consisted of one monovalent, one bivalent, one trivalent, two tetravalents, one hexavalent construct, and two tetravalents incorporating coiled-coil repeats regions from LSA3 and p27 vaccine candidates. RESULTS: All eight polyproteins induced a strong and homogeneous antibody response in mice of three distinct genotypes, with a dominance of cytophilic IgG subclasses, lasting up to six months after the last immunization. Vaccine-induced antibodies exerted a strong monocyte-mediated in vitro inhibition of P. falciparum growth. Naturally acquired antibodies from individuals living in an endemic area of Senegal recognized the polyproteins with a reactivity mainly constituted of cytophilic IgG subclasses. CONCLUSIONS: Combination of genetically conserved and antigenically related MSP3 proteins provides promising subunit vaccine constructs, with improved features as compared to the first generation construct employed in clinical trials (MSP3-LSP). These multivalent MSP3 vaccine constructs expand the epitope display of MSP3 family proteins, and lead to the efficient induction of a wider range of antibody subclasses, even in genetically different mice. These findings are promising for future immunization of genetically diverse human populations

Sequence Conservation in Plasmodium falciparum α-Helical Coiled Coil Domains Proposed for Vaccine Development

BACKGROUND: The availability of the P. falciparum genome has led to novel ways to identify potential vaccine candidates. A new approach for antigen discovery based on the bioinformatic selection of heptad repeat motifs corresponding to alpha-helical coiled coil structures yielded promising results. To elucidate the question about the relationship between the coiled coil motifs and their sequence conservation, we have assessed the extent of polymorphism in putative alpha-helical coiled coil domains in culture strains, in natural populations and in the single nucleotide polymorphism data available at PlasmoDB. METHODOLOGY/PRINCIPAL FINDINGS: 14 alpha-helical coiled coil domains were selected based on preclinical experimental evaluation. They were tested by PCR amplification and sequencing of different P. falciparum culture strains and field isolates. We found that only 3 out of 14 alpha-helical coiled coils showed point mutations and/or length polymorphisms. Based on promising immunological results 5 of these peptides were selected for further analysis. Direct sequencing of field samples from Papua New Guinea and Tanzania showed that 3 out of these 5 peptides were completely conserved. An in silico analysis of polymorphism was performed for all 166 putative alpha-helical coiled coil domains originally identified in the P. falciparum genome. We found that 82% (137/166) of these peptides were conserved, and for one peptide only the detected SNPs decreased substantially the probability score for alpha-helical coiled coil formation. More SNPs were found in arrays of almost perfect tandem repeats. In summary, the coiled coil structure prediction was rarely modified by SNPs. The analysis revealed a number of peptides with strictly conserved alpha-helical coiled coil motifs. CONCLUSION/SIGNIFICANCE: We conclude that the selection of alpha-helical coiled coil structural motifs is a valuable approach to identify potential vaccine targets showing a high degree of conservation

The antibody response to Plasmodium falciparum Merozoite Surface Protein 4: comparative assessment of specificity and growth inhibitory antibody activity to infection-acquired and immunization-induced epitopes

<p>Abstract</p> <p>Background</p> <p>Malaria remains a global public health challenge. It is widely believed that an effective vaccine against malaria will need to incorporate multiple antigens from the various stages of the parasite's complex life cycle. <it>Plasmodium falciparum </it>Merozoite Surface Protein 4 (MSP4) is a vaccine candidate that has been selected for development for inclusion in an asexual stage subunit vaccine against malaria.</p> <p>Methods</p> <p>Nine monoclonal antibodies (Mabs) were produced against <it>Escherichia coli</it>-expressed recombinant MSP4 protein and characterized. These Mabs were used to develop an MSP4-specific competition ELISA to test the binding specificity of antibodies present in sera from naturally <it>P. falciparum</it>-infected individuals from a malaria endemic region of Vietnam. The Mabs were also tested for their capacity to induce <it>P. falciparum </it>growth inhibition <it>in vitro </it>and compared against polyclonal rabbit serum raised against recombinant MSP4</p> <p>Results</p> <p>All Mabs reacted with native parasite protein and collectively recognized at least six epitopes. Four of these Mabs recognize reduction-sensitive epitopes within the epidermal growth factor-like domain found near the C-terminus of MSP4. These sera were shown to contain antibodies capable of inhibiting the binding of the six Mabs indicating infection-acquired responses to the six different epitopes of MSP4. All of the six epitopes were readily recognized by human immune sera. Competition ELISA titres varied from 20 to 640, reflecting heterogeneity in the intensity of the humoral response against the protein among different individuals. The IgG responses during acute and convalescent phases of infection were higher to epitopes in the central region than to other parts of MSP4. Immunization with full length MSP4 in Freund's adjuvant induced rabbit polyclonal antisera able to inhibit parasite growth <it>in vitro </it>in a manner proportionate to the antibody titre. By contrast, polyclonal antisera raised to individual recombinant fragments rMSP4A, rMSP4B, rMSP4C and rMSP4D gave negligible inhibition. Similarly, murine Mabs alone or in combination did not inhibit parasite growth.</p> <p>Conclusions</p> <p>The panel of MSP4-specific Mabs produced were found to recognize six distinct epitopes that are also targeted by human antibodies during natural malaria infection. Antibodies directed to more than three epitope regions spread across MSP4 are likely to be required for <it>P. falciparum </it>growth inhibition <it>in vitro</it>.</p

Understanding Human-Plasmodium falciparum Immune Interactions Uncovers the Immunological Role of Worms

BACKGROUND: Former studies have pointed to a monocyte-dependent effect of antibodies in protection against malaria and thereby to cytophilic antibodies IgG1 and IgG3, which trigger monocyte receptors. Field investigations have further documented that a switch from non-cytophilic to cytophilic classes of antimalarial antibodies was associated with protection. The hypothesis that the non-cytophilic isotype imbalance could be related to concomittant helminthic infections was supported by several interventions and case-control studies. METHODS AND FINDINGS: We investigated here the hypothesis that the delayed acquisition of immunity to malaria could be related to a worm-induced Th2 drive on antimalarial immune responses. IgG1 to IgG4 responses against 6 different parasite-derived antigens were analyzed in sera from 203 Senegalese children, half carrying intestinal worms, presenting 421 clinical malaria attacks over 51 months. Results show a significant correlation between the occurrence of malaria attacks, worm carriage (particularly that of hookworms) and a decrease in cytophilic IgG1 and IgG3 responses and an increase in non-cytophilic IgG4 response to the merozoite stage protein 3 (MSP3) vaccine candidate. CONCLUSION: The results confirm the association with protection of anti-MSP3 cytophilic responses, confirm in one additional setting that worms increase malaria morbidity and show a Th2 worm-driven pattern of anti-malarial immune responses. They document why large anthelminthic mass treatments may be worth being assessed as malaria control policies

Long-Term Clinical Protection from Falciparum Malaria Is Strongly Associated with IgG3 Antibodies to Merozoite Surface Protein 3

Using data from malaria cases in Senegal, Pierre Druilhe and colleagues found that antibodies of the IgG3 isotype directed to merozoite surface protein 3 (MSP3) were strongly predictive of clinical outcome

A Conserved Multi-Gene Family Induces Cross-Reactive Antibodies Effective in Defense against Plasmodium falciparum

BACKGROUND: Two related merozoite surface proteins, MSP3 and MSP6, have previously been identified as targets of antibody-dependent cellular inhibition (ADCI), a protective mechanism against Plasmodium falciparum malaria. Both MSP3 and MSP6 share a common characteristic small N-terminal signature amino-acid stretch (NLRNA/G), a feature similar to MSP3-like orthologs identified in other human and primate malaria parasites. METHODS/RESULTS: This signature amino-acid sequence led to the identification of eight ORFs contiguously located on P. falciparum chromosome 10. Our subsequent investigations on their expression, localization, sequence conservation, epitope sharing, immunogenicity and the functional role of antibodies in defense are reported here. Six members of P. falciparum MSP3-multigene family share similar sequence organization within their C-terminal regions, are simultaneously expressed as merozoite surface proteins and are highly conserved among parasite isolates. Each of these proteins is a target of naturally occurring antibodies effective at parasite killing in ADCI assays. Moreover, both naturally occurring antibodies and those generated by immunization display cross-reactivity with other members of the family and exhibit varied binding avidities. CONCLUSIONS/SIGNIFICANCE: The unusual characteristics of the MSP3 multi-gene family lead us to hypothesize that the simultaneous expression of targets eliciting cross-reactive antibody responses capable of controlling parasite densities could represent an immune process selected through evolution to maintain homeostasis between P. falciparum and human hosts; a process that allows the continuous transmission of the parasite without killing the host. Our observations also have practical consequences for vaccine development by suggesting MSP3 vaccine efficacy might be improved when combined with the various C-terminus regions of the MSP3 family members to generate a wider range of antibodies acting and to increase vaccine immunogenicity in varied human genetic backgrounds

Opsonising antibodies to P. falciparum Merozoites associated with immunity to clinical malaria

Naturally acquired humoral immunity to the malarial parasite Plasmodium falciparum can protect against disease, although the precise mechanisms remain unclear. Although antibody levels can be measured by ELISA, few studies have investigated functional antibody assays in relation to clinical outcomes. In this study we applied a recently developed functional assay of antibody-mediated opsonisation of merozoites, to plasma samples from a longitudinal cohort study conducted in a malaria endemic region of Papua New Guinea (PNG). Phagocytic activity was quantified by flow cytometry using a standardized and high-throughput protocol, and was subsequently evaluated for association with protection from clinical malaria and high-density parasitemia. Opsonising antibody responses were found to: i) increase with age, ii) be enhanced by concurrent infection, and iii) correlate with protection from clinical episodes and high-density parasitemia. Stronger protective associations were observed in individuals with no detectable parasitemia at baseline. This study presents the first evidence for merozoite phagocytosis as a correlate of acquired immunity and clinical protection against P. falciparum malaria