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Malaria Journal Jan 2021Plasmodium falciparum causes the majority of malaria cases worldwide and children in sub-Saharan Africa are the most vulnerable group affected. Non-sterile clinical...
BACKGROUND
Plasmodium falciparum causes the majority of malaria cases worldwide and children in sub-Saharan Africa are the most vulnerable group affected. Non-sterile clinical immunity that protects from symptoms develops slowly and is relatively short-lived. Moreover, current malaria vaccine candidates fail to induce durable high-level protection in endemic settings, possibly due to the immunomodulatory effects of the malaria parasite itself. Because dendritic cells play a crucial role in initiating immune responses, the aim of this study was to better understand the impact of cumulative malaria exposure as well as concurrent P. falciparum infection on dendritic cell phenotype and function.
METHODS
In this cross-sectional study, the phenotype and function of dendritic cells freshly isolated from peripheral blood samples of Malian adults with a lifelong history of malaria exposure who were either uninfected (n = 27) or asymptomatically infected with P. falciparum (n = 8) was assessed. Additionally, plasma cytokine and chemokine levels were measured in these adults and in Malian children (n = 19) with acute symptomatic malaria.
RESULTS
With the exception of lower plasmacytoid dendritic cell frequencies in asymptomatically infected Malian adults, peripheral blood dendritic cell subset frequencies and HLA-DR surface expression did not differ by infection status. Peripheral blood myeloid dendritic cells of uninfected Malian adults responded to in vitro stimulation with P. falciparum blood-stage parasites by up-regulating the costimulatory molecules HLA-DR, CD80, CD86 and CD40 and secreting IL-10, CXCL9 and CXCL10. In contrast, myeloid dendritic cells of asymptomatically infected Malian adults exhibited no significant responses above the uninfected red blood cell control. IL-10 and CXCL9 plasma levels were elevated in both asymptomatic adults and children with acute malaria.
CONCLUSIONS
The findings of this study indicate that myeloid dendritic cells of uninfected adults with a lifelong history of malaria exposure are able to up-regulate co-stimulatory molecules and produce cytokines. Whether mDCs of malaria-exposed individuals are efficient antigen-presenting cells capable of mounting an appropriate immune response remains to be determined. The data also highlights IL-10 and CXCL9 as important factors in both asymptomatic and acute malaria and add to the understanding of asymptomatic P. falciparum infections in malaria-endemic areas.
Topics: Adult; Asymptomatic Infections; Chemokines; Child; Child, Preschool; Cross-Sectional Studies; Cytokines; Dendritic Cells; Erythrocytes; Female; Humans; Malaria; Malaria, Falciparum; Male; Mali; Middle Aged; Phenotype; Plasmodium falciparum
PubMed: 33407502
DOI: 10.1186/s12936-020-03533-w -
Ortopedia, Traumatologia, Rehabilitacja Oct 2021Enchondromas are the most common benign bone tumours found in the hand. They are usually accidentally diagnosed on an X-ray, because they grow asymptomatically. In some...
BACKGROUND
Enchondromas are the most common benign bone tumours found in the hand. They are usually accidentally diagnosed on an X-ray, because they grow asymptomatically. In some cases, a pathological fracture of the involved phalanx may be the first sign. The objective of this study was to assess the results of operative treatment of enchondromas involving hand phalanges and metacarpals.
MATERIAL AND METHODS
The study group consisted of 24 patients, 16 women (67%) and 8 men, (33%), aged a mean of 31 years, who were operated on at our centre. The surgery consisted in curettage, and - in most cases - filling the bone defect with either a bone graft or a bone substitute. Follow-up assessment was performed over the telephone in 17 patients (79% of the group) at a mean of 2 years after surgery.
RESULTS
Half of the patients were asymptomatic and fully recovered functionally, whereas the other half complained of some not troublesome symptoms such as scar discomfort, limitation of finger movement or cold sensitivity. No differences were observed with regard to the material used for filling of the bone defect following curettage. Two cases of recurrence were noted after surgery: one in the bone substitute group and one in the bone graft group.
CONCLUSIONS
1. Enchondromas are the most common benign bone tumours encountered in bones of the hand. 2. The first line treatment in these lesions is curettage and filling of the bone defect with a bone sub-stitute or cancellous bone graft. 3. Both the results of the present study and literature data show that the approach to managing the tu-mour cavity after curettage has no significant effect on outcomes, which are essentially satisfactory.
Topics: Aged; Bone Neoplasms; Chondroma; Curettage; Female; Hand; Humans; Male; Neoplasm Recurrence, Local; Retrospective Studies
PubMed: 34734563
DOI: 10.5604/01.3001.0015.4344 -
Allergy Feb 2021The missing asymptomatic COVID-19 infections have been overlooked because of the imperfect sensitivity of the nucleic acid testing (NAT). Globally understanding the...
BACKGROUND
The missing asymptomatic COVID-19 infections have been overlooked because of the imperfect sensitivity of the nucleic acid testing (NAT). Globally understanding the humoral immunity in asymptomatic carriers will provide scientific knowledge for developing serological tests, improving early identification, and implementing more rational control strategies against the pandemic.
MEASURE
Utilizing both NAT and commercial kits for serum IgM and IgG antibodies, we extensively screened 11 766 epidemiologically suspected individuals on enrollment and 63 asymptomatic individuals were detected and recruited. Sixty-three healthy individuals and 51 mild patients without any preexisting conditions were set as controls. Serum IgM and IgG profiles were further probed using a SARS-CoV-2 proteome microarray, and neutralizing antibody was detected by a pseudotyped virus neutralization assay system. The dynamics of antibodies were analyzed with exposure time or symptoms onset.
RESULTS
A combination test of NAT and serological testing for IgM antibody discovered 55.5% of the total of 63 asymptomatic infections, which significantly raises the detection sensitivity when compared with the NAT alone (19%). Serum proteome microarray analysis demonstrated that asymptomatics mainly produced IgM and IgG antibodies against S1 and N proteins out of 20 proteins of SARS-CoV-2. Different from strong and persistent N-specific antibodies, S1-specific IgM responses, which evolved in asymptomatic individuals as early as the seventh day after exposure, peaked on days from 17 days to 25 days, and then disappeared in two months, might be used as an early diagnostic biomarker. 11.8% (6/51) mild patients and 38.1% (24/63) asymptomatic individuals did not produce neutralizing antibody. In particular, neutralizing antibody in asymptomatics gradually vanished in two months.
CONCLUSION
Our findings might have important implications for the definition of asymptomatic COVID-19 infections, diagnosis, serological survey, public health, and immunization strategies.
Topics: Adult; Aged; Antibodies, Neutralizing; Antibodies, Viral; COVID-19; COVID-19 Testing; Carrier State; Female; Humans; Immunoglobulin G; Immunoglobulin M; Male; Middle Aged; SARS-CoV-2
PubMed: 33040337
DOI: 10.1111/all.14622 -
Frontiers in Oncology 2023EBV is a lymphotropic virus, member of the family that asymptomatically infects more than 90% of the human population, establishing a latent infection in memory B... (Review)
Review
EBV is a lymphotropic virus, member of the family that asymptomatically infects more than 90% of the human population, establishing a latent infection in memory B cells. EBV exhibits complex survival and persistence dynamics, replicating its genome through the proliferation of infected B cells or production of the lytic virions. Many studies have documented the infection of T/NK cells by EBV in healthy individuals during and after primary infection. This feature has been confirmed in humanized mouse models. Together these results have challenged the hypothesis that the infection of T/NK cells by EBV could be a triggering event for lymphomagenesis. Extranodal NK/T-cell lymphoma (ENKTCL) and Epstein-Barr virus (EBV)-positive nodal T- and NK-cell lymphoma (NKTCL) are two EBV-associated lymphomas of T/NK cells. These two lymphomas display different clinical, histological and molecular features. However, they share two intriguing characteristics: the association with EBV and a geographical prevalence in East Asia and Latin America. In this review we will discuss the genetic characteristics of EBV in order to understand the possible role of this virus in the oncogenesis of ENKTCL and NKTCL. In addition, the main immunohistological, molecular, cytogenetic and epigenetic differences between ENKTCL and NKTCL will be discussed, as well as EBV differences in latency patterns and other viral molecular characteristics.
PubMed: 37781191
DOI: 10.3389/fonc.2023.1240359 -
Radiologie (Heidelberg, Germany) Dec 2023Cystic pancreatic lesions are detected incidentally at an increasing rate. Often, the patients present asymptomatically. Hence, the resulting clinical consequences... (Review)
Review
BACKGROUND
Cystic pancreatic lesions are detected incidentally at an increasing rate. Often, the patients present asymptomatically. Hence, the resulting clinical consequences remain challenging and unsettling for both physicians and patients.
OBJECTIVES
Status of current recommendations in handling cystic pancreatic lesions.
MATERIALS AND METHODS
Selective literature search of PubMed while taking current guidelines into account.
RESULTS
Correct diagnostic classification of the cystic lesion is crucial since further action depends on the type of cystic lesion. Resection is generally recommended for mucinous cystic neoplasms (MCN), solid pseudopapillary neoplasms (SPN), and intraductal papillary mucinous neoplasms (IPMN) with relevant risk criteria such as prominent main-duct dilation. Surveillance is recommended for IPMN without risk criteria, as long as comorbidities and life expectancy of the patient will allow preventive resection over the years. SCNs are benign and only symptomatic SCNs require resection. Inflammatory pancreatic cysts should only be treated under certain circumstances.
Topics: Humans; Pancreatic Cyst; Pancreatic Intraductal Neoplasms; Carcinoma, Pancreatic Ductal; Pancreas; Pancreatic Neoplasms; Neoplasms, Cystic, Mucinous, and Serous
PubMed: 37878017
DOI: 10.1007/s00117-023-01226-4 -
International Journal of Infectious... Apr 2021The performance of the Roche Elecsys® Anti-SARS-CoV-2, Abbott Architect SARS-CoV-2 IgM, Abbott Architect SARS-CoV-2 IgG, Euroimmun SARS-CoV-2 IgA, Euroimmun SARS-CoV-2...
BACKGROUND
The performance of the Roche Elecsys® Anti-SARS-CoV-2, Abbott Architect SARS-CoV-2 IgM, Abbott Architect SARS-CoV-2 IgG, Euroimmun SARS-CoV-2 IgA, Euroimmun SARS-CoV-2 IgG ELISA, and Trillium IgG/IgM rapid assays was evaluated in Jamaica.
METHODS
Diagnostic sensitivities of the assays were assessed by testing serum samples from SARS-CoV-2 PCR-confirmed persons and diagnostic specificity was assessed by testing serum samples collected during 2018-2019 from healthy persons and from persons with antibodies to a wide range of viral infections.
RESULTS
Serum samples collected ≥14 days after onset of symptoms, or an initial SARS-CoV-2 RT-PCR positive test for asymptomatics, showed diagnostic sensitivities ranging from 67.9 to 75.0% when including all possible disease severities and increased to 90.0-95.0% when examining those with moderate to critical disease. Grouping moderate to critical disease showed a significant association with a SARS-CoV-2 antibody positive result for all assays. Diagnostic specificity ranged from 96.7 to 100.0%. For all assays examined, SARS-CoV-2 real-time PCR cycle threshold (Ct) values of the initial nasopharyngeal swab sample testing positive were significantly different for samples testing antibody positive versus negative.
CONCLUSIONS
These data from a predominantly African descent Caribbean population show comparable diagnostic sensitivities and specificities for all testing platforms assessed and limited utility of these tests for persons with asymptomatic and mild infections.
Topics: Antibodies, Viral; COVID-19; COVID-19 Serological Testing; Caribbean Region; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin M; Jamaica; SARS-CoV-2; Sensitivity and Specificity
PubMed: 33610776
DOI: 10.1016/j.ijid.2021.02.059 -
Molecules (Basel, Switzerland) Jun 2021A lichen is a symbiotic relationship between a fungus and a photosynthetic organism, which is algae or cyanobacteria. Endolichenic fungi are a group of microfungi that... (Review)
Review
A lichen is a symbiotic relationship between a fungus and a photosynthetic organism, which is algae or cyanobacteria. Endolichenic fungi are a group of microfungi that resides asymptomatically within the thalli of lichens. Endolichenic fungi can be recognized as luxuriant metabolic artists that produce propitious bioactive secondary metabolites. More than any other time, there is a worldwide search for new antibiotics due to the alarming increase in microbial resistance against the currently available therapeutics. Even though a few antimicrobial compounds have been isolated from endolichenic fungi, most of them have moderate activities, implying the need for further structural optimizations. Recognizing this timely need and the significance of endolichenic fungi as a promising source of antimicrobial compounds, the activity, sources and the structures of 31 antibacterial compounds, 58 antifungal compounds, two antiviral compounds and one antiplasmodial (antimalarial) compound are summarized in this review. In addition, an overview of the common scaffolds and structural features leading to the corresponding antimicrobial properties is provided as an aid for future studies. The current challenges and major drawbacks of research related to endolichenic fungi and the remedies for them have been suggested.
Topics: Anti-Infective Agents; Lichens
PubMed: 34202392
DOI: 10.3390/molecules26133901 -
Frontiers in Cellular and Infection... 2022and are two obligate human pathogens that have evolved to be uniquely adapted to their host. The meningococcus is frequently carried asymptomatically in the... (Review)
Review
and are two obligate human pathogens that have evolved to be uniquely adapted to their host. The meningococcus is frequently carried asymptomatically in the nasopharynx, while gonococcal infection of the urogenital tract usually elicits a marked local inflammatory response. Other members of the genus are abundant in the upper airway where they could engage in co-operative or competitive interactions with both these pathogens. Here, we briefly outline the potential sites of contact between spp. in the body, with emphasis on the upper airway, and describe the growing yet circumstantial evidence for antagonism from carriage studies and human volunteer challenge models with . Recent laboratory studies have characterized antagonistic mechanisms that enable competition between species. Several of these mechanisms, including Multiple Adhesin family (Mafs), Two Partner Secretion Systems, and Type VI secretion system, involve direct contact between bacteria; the genetic organisation of these systems, and the domain structure of their effector molecules have striking similarities. Additionally, DNA from one species of can be toxic to another species, following uptake. More research is needed to define the full repertoire of antagonistic mechanisms in spp., their distribution in strains, their range of activity, and contribution to survival . Understanding the targets of effectors could reveal how antagonistic relationships between close relatives shape subsequent interactions between pathogens and their hosts.
Topics: Conflict of Interest; Humans; Nasopharynx; Neisseria; Neisseria gonorrhoeae; Neisseria meningitidis
PubMed: 35811666
DOI: 10.3389/fcimb.2022.913292 -
General Thoracic and Cardiovascular... Feb 2022Cardiac tumours are some of the rarest primary tumours, while cardiac metastasis are more common yet still relatively rare. Seventy five percent of primary cardiac... (Review)
Review
Cardiac tumours are some of the rarest primary tumours, while cardiac metastasis are more common yet still relatively rare. Seventy five percent of primary cardiac tumours are benign tumours. Cardiac tumours present with a range of obstructive, embolic, arrhythmic or systemic symptoms, and in many cases may present asymptomatically. The clinical presentation depends largely on the size and location of the mass. With advances in cardiac imagining and the introduction of cardiopulmonary bypass, the diagnosis and surgical treatment of these rare tumours has improved the prognosis and outlook for benign and malignant tumours. Management depends on tumour histology, size and location as well as the clinical presentation. Conservative management is reserved for small, benign tumours that can undergo regular echocardiographic follow-up. Symptomatic benign tumours are treated with surgical resection and the results are excellent. Malignant primary cardiac tumours have a poor prognosis with high rates of relapse and a median survival of 10-24 months.
Topics: Echocardiography; Heart Neoplasms; Humans; Myxoma; Neoplasm Recurrence, Local; Prognosis
PubMed: 35000140
DOI: 10.1007/s11748-021-01754-7 -
Malaria Journal Sep 2021Further reductions in malaria incidence as more countries approach malaria elimination require the identification and treatment of asymptomatic individuals who carry...
BACKGROUND
Further reductions in malaria incidence as more countries approach malaria elimination require the identification and treatment of asymptomatic individuals who carry mosquito-infective Plasmodium gametocytes that are responsible for furthering malaria transmission. Assessing the relationship between total parasitaemia and gametocytaemia in field surveys can provide insight as to whether detection of low-density, asymptomatic Plasmodium falciparum infections with sensitive molecular methods can adequately detect the majority of infected individuals who are potentially capable of onward transmission.
METHODS
In a cross-sectional survey of 1354 healthy children and adults in three communities in western Kenya across a gradient of malaria transmission (Ajigo, Webuye, and Kapsisywa-Kipsamoite), asymptomatic P. falciparum infections were screened by rapid diagnostic tests, blood smear, and quantitative PCR of dried blood spots targeting the varATS gene in genomic DNA. A multiplex quantitative reverse-transcriptase PCR assay targeting female and male gametocyte genes (pfs25, pfs230p), a gene with a transcriptional pattern restricted to asexual blood stages (piesp2), and human GAPDH was also developed to determine total parasite and gametocyte densities among parasitaemic individuals.
RESULTS
The prevalence of varATS-detectable asymptomatic infections was greatest in Ajigo (42%), followed by Webuye (10%). Only two infections were detected in Kapsisywa. No infections were detected in Kipsamoite. Across all communities, children aged 11-15 years account for the greatest proportion total and sub-microscopic asymptomatic infections. In younger age groups, the majority of infections were detectable by microscopy, while 68% of asymptomatically infected adults (> 21 years old) had sub-microscopic parasitaemia. Piesp2-derived parasite densities correlated poorly with microscopy-determined parasite densities in patent infections relative to varATS-based detection. In general, both male and female gametocytaemia increased with increasing varATS-derived total parasitaemia. A substantial proportion (41.7%) of individuals with potential for onward transmission had qPCR-estimated parasite densities below the limit of microscopic detection, but above the detectable limit of varATS qPCR.
CONCLUSIONS
This assessment of parasitaemia and gametocytaemia in three communities with different transmission intensities revealed evidence of a substantial sub-patent infectious reservoir among asymptomatic carriers of P. falciparum. Experimental studies are needed to definitively determine whether the low-density infections in communities such as Ajigo and Webuye contribute significantly to malaria transmission.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Asymptomatic Infections; Child; Child, Preschool; Cross-Sectional Studies; Female; Humans; Infant; Kenya; Malaria, Falciparum; Male; Middle Aged; Prevalence; Rural Population; Young Adult
PubMed: 34535134
DOI: 10.1186/s12936-021-03905-w