ABSTRACT
PURPOSE: The purpose of this retrospective study was to describe our preliminary results of intra-meniscal administration of platelet rich plasma (PRP) in patients with degenerative meniscal tears of the knee. MATERIAL AND METHOD: Ten patients with degenerative meniscal tears according to the Stoller classification and without knee osteoarthritis were included. There were 7 men and 3 women with a mean age of 40.4±13.6 [SD] years (range: 18-59 years). Patients were prospectively assessed at baseline and 3- and 6-months after intra meniscal PRP administration. Evaluation included the knee injury and osteoarthritis outcome score (KOOS), pain visual analog scale, and return to competition and training. MRI follow-up was performed 6 months after PRP administration. Adverse events were recorded. RESULTS: Volume of injected PRP was standardized to 4.0mL. Adverse events during PRP administration was moderate pain in 8 patients (8/10; 80%). Mean KOOS total score significantly improved from 56.6±15.7 (SD) to 72.7±18.5 (SD) (P=0.0007). All six patients practicing sports regularly were able to recover competition or training. In seven patients who underwent MRI follow-up at 6 months, MRI showed stability of the meniscal tears and similar Stoller grades. CONCLUSION: Intra-meniscal administration of PRP under ultrasound guidance directly into meniscal degenerative lesions is feasible and safe. Further randomized controlled studies are needed to definitely confirm the effectiveness of this procedure.
Subject(s)
Platelet-Rich Plasma , Tibial Meniscus Injuries/therapy , Adolescent , Adult , Female , Humans , Injections, Intralesional , Male , Middle Aged , Retrospective Studies , Young AdultABSTRACT
OBJECTIVE: The teaching hospital of Nancy, France, implemented a specific multidisciplinary care pathway (French acronym AMDPL) to improve the management of patients presenting with Lyme borreliosis (LB) suspicion. We aimed to assess the first year of activity of this care pathway. PATIENTS AND METHODS: We included all patients managed in the AMDPL pathway from November 1, 2016 to October 31, 2017. The first step was a dedicated Lyme disease consultation with an infectious disease specialist. Following this consultation, the LB diagnosis was either confirmed and adequate treatment was prescribed, or a differential diagnosis was established and patients received adequate management, or further investigations were required and patients were offered multidisciplinary management as part of a day hospitalization. RESULTS: A total of 468 patients were included. LB diagnosis was confirmed in 15% of patients (69/468), 49% of patients received a differential diagnosis, and 26% (122/468) of patients had the LB diagnosis ruled out without receiving any other diagnosis. CONCLUSIONS: This is to our knowledge the first multidisciplinary center implemented in France for the management of patients presenting with LB suspicion related to polymorphous signs and symptoms. Several diagnoses could be confirmed or corrected, although some symptoms and complaints could not be explained. This cohort could improve our knowledge of LB and its differential diagnoses.
Subject(s)
Lyme Disease , Disease Management , France , Hospitals, Teaching , Humans , Lyme Disease/diagnosis , Lyme Disease/therapyABSTRACT
The human cytomegalovirus (HCMV) terminase complex consists of several components acting together to cleave viral DNA into unit length genomes and translocate them into capsids, a critical process in the production of infectious virions subsequent to DNA replication. Previous studies suggest that the carboxyl-terminal portion of the pUL56 subunit interacts with the pUL89 subunit. However, the specific interacting residues of pUL56 remain unknown. We identified a conserved sequence in the C-terminal moiety of pUL56 (671WMVVKYMGFF680). Overrepresentation of conserved aromatic amino acids through 20 herpesviruses homologues of pUL56 suggests an involvement of this short peptide into the interaction between the larger pUL56 terminase subunit and the smaller pUL89 subunit. Use of Alpha technology highlighted an interaction between pUL56 and pUL89 driven through the peptide 671WMVVKYMGFF680. A deletion of these residues blocks viral replication. We hypothesize that it is the consequence of the disruption of the pUL56-pUL89 interaction. These results show that this motif is essential for HCMV replication and could be a target for development of new small antiviral drugs or peptidomimetics.
Subject(s)
Protein Interaction Domains and Motifs , Protein Subunits , Viral Proteins/metabolism , Viral Structural Proteins/metabolism , Amino Acid Sequence , Cell Line , Conserved Sequence , Cytomegalovirus/physiology , Humans , Protein Binding , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Structural Proteins/chemistry , Viral Structural Proteins/genetics , Virus ReplicationABSTRACT
INTRODUCTION: Arrhythmic disorders are infrequent in young adult and should evoke myopathy associated cardiomyopathy, even though muscular symptoms are moderate or absent. CASE REPORT: We report a 25-year-old woman who developed severe supraventricular rhythm disturbances with exercise intolerance and elevated serum creatine kinase level. Initially the echocardiography showed normal ventricular function. Mutation in the lamin gene (LMNA) was identified. During the disease course, arrhythmia and ventricular function worsened and required cardioverter defibrillator implantation. CONCLUSION: Laminopathies are genetic disorders among which dilated cardiomyopathy associated with skeletal muscular involvement is the most frequent phenotype, usually like Emery-Dreifuss muscular dystrophy. Other phenotypes are progeria, lipodystrophic syndromes and peripheral neuropathy. Cardiac involvement is responsible for syncope, thromboembolic events and sudden death and often requires early cardioverter defibrillator implantation.
Subject(s)
Arrhythmias, Cardiac/diagnosis , Exercise Tolerance , Lamin Type A/genetics , Muscular Dystrophies/diagnosis , Myalgia/diagnosis , Adult , Arrhythmias, Cardiac/etiology , Female , Humans , Muscle Weakness/diagnosis , Muscle Weakness/etiology , Muscular Dystrophies/genetics , Mutation , Myalgia/etiology , Young AdultABSTRACT
KEY MESSAGE: A fully acetylated, soluble CO preparation of mean DP of ca. 7 was perceived with high sensitivity by M. truncatula in a newly designed versatile root elicitation assay. The root system of legume plants interacts with a large variety of microorganisms, either pathogenic or symbiotic. Understanding how legumes recognize and respond specifically to pathogen-associated or symbiotic signals requires the development of standardized bioassays using well-defined preparations of the corresponding signals. Here we describe the preparation of chitin oligosaccharide (CO) fractions from commercial chitin and their characterization by a combination of liquid-state and solid-state nuclear magnetic resonance spectroscopy. We show that the CO fraction with highest degree of polymerization (DP) became essentially insoluble after lyophilization. However, a fully soluble, fully acetylated fraction with a mean DP of ca. 7 was recovered and validated by showing its CERK1-dependent activity in Arabidopsis thaliana. In parallel, we developed a versatile root elicitation bioassay in the model legume Medicago truncatula, using a hydroponic culture system and the Phytophthora ß-glucan elicitor as a control elicitor. We then showed that M. truncatula responded with high sensitivity to the CO elicitor, which caused the production of extracellular reactive oxygen species and the transient induction of a variety of defense-associated genes. In addition, the bioassay allowed detection of elicitor activity in culture filtrates of the oomycete Aphanomyces euteiches, opening the way to the analysis of recognition of this important legume root pathogen by M. truncatula.
Subject(s)
Chitin/pharmacology , Medicago truncatula/physiology , Plant Roots/physiology , Acetylation , Aphanomyces , Arabidopsis/physiology , Arabidopsis Proteins/metabolism , Chitin/chemistry , Gene Expression Regulation, Plant , Magnetic Resonance Spectroscopy , Medicago truncatula/drug effects , Medicago truncatula/genetics , Phytophthora , Plant Diseases , Plant Roots/drug effects , Plant Roots/genetics , Polymerization , Protein Serine-Threonine Kinases/metabolism , Reactive Oxygen Species/metabolismABSTRACT
We report the case of a 54-year-old patient admitted to an emergency department, because of a thoracic pain suspicious for angina pectoris. Although the patient had become asymptomatic on admission, his electrocardiogram presented abnormalities (biphasic T waves in V1 to V4 ) which prompted a diagnosis of unstable angina.This electrocardiophic pattern is known as Wellens' syndrome.
Subject(s)
Coronary Stenosis/diagnosis , Electrocardiography , Humans , Male , Middle Aged , SyndromeABSTRACT
p300/CREB binding protein-associated factor (PCAF) regulates gene expression by acting through histone acetylation and as a transcription coactivator. Although histone acetyltransferases were involved in the toxicity induced by amyloid-beta (Abeta) peptides, nothing is known about PCAF. We here analyzed the sensitivity of PCAF knockout (KO) mice to the toxic effects induced by i.c.v. injection of Abeta(25-35) peptide, a nontransgenic model of Alzheimer's disease. PCAF wild-type (WT) and KO mice received Abeta(25-35) (1, 3 or 9 nmol) or scrambled Abeta(25-35) (9 nmol) as control. After 7 days, Abeta(25-35) toxicity was measured in the hippocampus of WT mice by a decrease in CA1 pyramidal cells and increases in oxidative stress, endoplasmic reticulum stress and induction of apoptosis. Memory deficits were observed using spontaneous alternation, water-maze learning and passive avoidance. Non-treated PCAF KO mice showed a decrease in CA1 cells and learning alterations. However, Abeta(25-35) injection failed to induce toxicity or worsen the deficits. This resistance to Abeta(25-35) toxicity did not involve changes in glutamate or acetylcholine systems. Examination of enzymes involved in Abeta generation or degradation revealed changes in transcription of presenilins, activity of neprilysin (NEP) and an absence of Abeta(25-35)-induced regulation of NEP activity in PCAF KO mice, partly due to an altered expression of somatostatin (SRIH). We conclude that PCAF regulates the expression of proteins involved in Abeta generation and degradation, thus rendering PCAF KO insensitive to amyloid toxicity. Modulating acetyltransferase activity may offer a new way to develop anti-amyloid therapies.
Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/toxicity , Brain/metabolism , Drug Resistance/genetics , Genetic Predisposition to Disease/genetics , Peptide Fragments/toxicity , p300-CBP Transcription Factors/genetics , Alzheimer Disease/genetics , Alzheimer Disease/physiopathology , Amyloid beta-Peptides/metabolism , Animals , Apoptosis/drug effects , Apoptosis/genetics , Brain/physiopathology , Disease Models, Animal , Hippocampus/drug effects , Hippocampus/metabolism , Hippocampus/pathology , Memory Disorders/chemically induced , Memory Disorders/genetics , Memory Disorders/metabolism , Mice , Mice, Knockout , Neprilysin/drug effects , Neprilysin/genetics , Neprilysin/metabolism , Nerve Degeneration/chemically induced , Nerve Degeneration/genetics , Nerve Degeneration/metabolism , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Oxidative Stress/drug effects , Oxidative Stress/genetics , Peptide Fragments/metabolism , Presenilins/drug effects , Presenilins/genetics , Presenilins/metabolism , Somatostatin/drug effects , Somatostatin/metabolismABSTRACT
Aphanomyces euteiches is a major soilborne oomycete pathogen that infects various legume species, including pea and alfalfa. The model legume Medicago truncatula has recently emerged as a valuable genetic system for understanding the genetic basis of resistance to A. euteiches in leguminous crops. The objective of this study was to identify genetic determinants of resistance to a broad host-range pea-infecting strain of A. euteiches in M. truncatula. Two M. truncatula segregating populations of 178 F(5) recombinant inbred lines and 200 F(3) families from the cross F83005.5 (susceptible) x DZA045.5 (resistant) were screened for resistance to A. euteiches. Phenotypic distributions observed suggested a dominant monogenic control of resistance. A major locus associated with resistance to A. euteiches, namely AER1, was mapped by bulk segregant analysis to a terminal end of chromosome 3 in M. truncatula and explained 88% of the phenotypic variation. AER1 was identified in a resistance-gene-rich region, where resistance gene analogs and genes associated with disease resistance phenotypes have been identified. Discovery of AER1 opens up new prospects for improving resistance to A. euteiches in cultivated legumes using a comparative genomics approach.
Subject(s)
Aphanomyces/physiology , Medicago truncatula/genetics , Medicago truncatula/microbiology , Plant Diseases/genetics , Chromosome Mapping , Chromosomes, Plant , Genes, Plant , Genetic Linkage , Genetic Predisposition to Disease , Genomics , Plant Diseases/microbiology , Plant Proteins/genetics , Plant Proteins/metabolismABSTRACT
A paradigmatic case of pulsus alternans observed during exploration of a severe aortic valve disease is reported. Pulsus alternans is a rare semiologic sign of severe left ventricular dysfunction and the mechanisms of its appearance are discussed.
Subject(s)
Aortic Valve Stenosis/diagnosis , Pulse , Ventricular Dysfunction, Left/diagnosis , Aged, 80 and over , Aortic Valve Stenosis/physiopathology , Electrocardiography , Female , Humans , Ventricular Dysfunction, Left/physiopathologyABSTRACT
RFLP of ITS rDNA is proposed as a useful tool for molecular identification of the most common species of biverticillate penicillia. 60 isolates were analysed representing 13 species and 21 unique sequences were produced. The combination of five restriction enzymes was successful in separating 12 species. However, the variety Penicillium purpurogenum var. rubrisclerotium remained indistinguishable from Penicillium funiculosum. P. funiculosum appeared as the most confused species, being mis-identified with Penicillium miniolutum and Penicillium pinophilum, which were originally part of the species, and with P. purpurogenum perhaps because of the common production of red pigment. Penicillium variabile was difficult to investigate as introns were found on half of the isolates. Penicillium piceum, Penicillium rugulosum, Penicillium loliense, Penicillium erythromellis and P. purpurogenum were homogeneous from molecular and morphological positions and corresponded to a well circumscribed taxon. Furthermore, intraspecific variability was evidenced within P. pinophilum and P. funiculosum. The ex-type isolate of P. funiculosum produced a unique pattern. The method is sensitive, rapid and inexpensive and can be used for isolate identification of the biverticillate species. It is recommended particularly when many isolates have to be authentificated prior to analysis for phylogenetic assessment or population genetics(AU)
Subject(s)
DNA, Fungal/genetics , DNA, Ribosomal/genetics , DNA, Ribosomal Spacer/genetics , Penicillium/classification , Penicillium/genetics , Penicillium/isolation & purification , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Phenotype , Phylogeny , Sensitivity and Specificity , Terminology as Topic , Species SpecificityABSTRACT
Intestinal obstruction is a rare but dreadful complication of pregnancy. Both the mother and the foetus may be severely affected and even die. The authors here report their recent experience and review the literature. They emphasize that diagnostic pitfalls are common during pregnancy and there appropriate management most often delayed. A multidisciplinary approach is advocated and the specific aspects of this high-risk situation are discussed.
Subject(s)
Intestinal Obstruction/diagnosis , Intestinal Obstruction/therapy , Pregnancy Complications/diagnosis , Pregnancy Complications/therapy , Adult , Female , Humans , Incidence , Intestinal Obstruction/epidemiology , Patient Care Team , PregnancyABSTRACT
Mandatory notification of listeriosis began in France in 1999. Enhanced public health surveillance, including routine molecular characterisation of Listeria monocytogenes strains, epidemiologic follow up of cases, and collection of food samples, has improved the sensitivity of outbreak detection and response. The incidence of listeriosis declined from 4.5 cases/million in 1999-2000 to approximately 3.5 cases/million during the period 2001-2003. Clinical, demographic and microbiological characteristics of listeriosis in France remained stable during this time period. Maternal-fetal infections accounted for 24% of all cases. Serovar 4b accounted for 49% of cases and 60% of case clusters. The incidence of listeriosis in France has declined and is now lower than in several other European countries.
Subject(s)
Listeriosis/epidemiology , Population Surveillance , Cluster Analysis , Female , Fetal Death , France/epidemiology , Humans , Incidence , Infant, Newborn , Infant, Newborn, Diseases/epidemiology , Infant, Newborn, Diseases/mortality , Listeria monocytogenes/classification , Listeriosis/microbiology , Listeriosis/mortality , Male , Pregnancy , Pregnancy Complications, Infectious/epidemiology , Risk Factors , Seasons , SerotypingABSTRACT
Genomic imprinting at the H19/Igf2 locus is governed by a cis-acting Imprinting-Control Region (ICR), located 2 kb upstream of the H19 gene. This region possesses an insulator function which is activated on the unmethylated maternal allele through the binding of the CTCF factor. It has been previously reported that paternal transmission of the H19(SilK) deletion, which removes the 3' portion of H19 ICR, leads to the loss of H19 imprinting. Here we show that, in the liver, this reactivation of the paternal H19 gene is concomitant to a dramatic decrease in Igf2 mRNA levels. This deletion alters higher-order chromatin architecture, Igf2 promoter usage and tissue-specific expression. Therefore, when methylated, the 3' portion of the H19 ICR is a bi-functional regulatory element involved not only in H19 imprinting but also in 'formatting' the higher-order chromatin structure for proper tissue-specific expression of both H19 and Igf2 genes.
Subject(s)
Gene Expression Regulation , Insulin-Like Growth Factor II/genetics , RNA, Untranslated/genetics , Animals , Crosses, Genetic , Female , Genomic Imprinting , Heart/physiology , Liver/physiology , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Organ Specificity , RNA, Long Noncoding , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Between 1999 and 2002, a routine survey of water quality in the Lac du Bourget was performed to study the dynamics and microcystin (MC) production of Planktothrix rubescens. Using liquid chromatography coupled to diode array detection and mass spectrometry, we found that two main variants ([D-Asp3] and [D-Asp3, Dhb7] microcystin-RR) were produced. The proportion of these two variants was not influenced by the depth or season of sampling. Expressed in microcystin-LR equivalents, high microcystin concentrations were recorded from August to December each year, reaching values of up to 6.7 microg L-1. A significant correlation was found between the microcystin cell content and the cell densities of P. rubescens. Cellular quotas of microcystins ranged from 0.1 to 0.3 pg cell-1. Simultaneously, laboratory experiments were performed on a strain of P. rubescens isolated from the lake to assess the potential impact of various P-PO4 (3-) concentrations on intra- and extracellular microcystin production. Unlike natural populations, this strain only produced [D-Asp3] MC-RR. The intracellular microcystin content was similarly correlated to the cell density, but the cellular quota was slightly higher (0.3-0.7 pg cell-1) than in the natural population. Again, as in the natural population, a linear relationship was found between growth rate and microcystin production rate. These findings support the hypothesis that environmental factors, such as phosphate concentrations, have no direct impact on microcystin production by P. rubescens, but act indirectly by affecting growth rate.
Subject(s)
Bacterial Toxins/biosynthesis , Cyanobacteria/metabolism , Environmental Monitoring , Fresh Water , Peptides, Cyclic/biosynthesis , Water Microbiology , Culture Media , Cyanobacteria/growth & development , Microcystins , Phosphorus , Water Pollutants/analysisABSTRACT
In addition to the economic consequences and threats associated with outbreaks, listeriosis remains of great public health concern, as it has one of the highest case fatality rates of all the foodborne infections (20%-30%), and has common source epidemic potential. Changes in the way food is produced, distributed and stored have created the potential for diffuse and widespread outbreaks involving many countries. In 2002, a survey was carried out to assess the need for and the feasibility of a European network on listeria infections in humans. Data on surveillance systems and laboratory methods were collected through two postal surveys sent to the national Centres for communicable disease surveillance and to the listeria reference laboratories. Surveillance systems for listeria infections were in operation in 16 out of the 17 countries surveyed, and 16 countries had a national reference laboratory (NRL). All countries based their case definition of listeriosis on the isolation of Listeria monocytogenes. Fourteen NRLs performed at least one typing method on human strains. At least 13 countries already carried out or expressed willingness to carry out characterisation of isolates by pulsed field gel electrophoresis (PFGE) of L. monocytogenes strains isolated from human cases following a standard protocol. The participants concluded that there was a clear added value to having a European surveillance network for listeria infections, particularly for outbreak detection and investigation, and that a surveillance network based on the existing national surveillance systems was feasible.
Subject(s)
Listeriosis , Population Surveillance , Disease Outbreaks , Europe , Humans , Incidence , Laboratories , Listeria monocytogenes/classification , Listeria monocytogenes/isolation & purification , Listeriosis/epidemiology , Listeriosis/microbiology , Microbial Sensitivity Tests , Quality Assurance, Health Care , Quality ControlABSTRACT
Several models have shown that virulence varies from one strain of Listeria monocytogenes to another, but little is known about the cause of low virulence. Twenty-six field L. monocytogenes strains were shown to be of low virulence in a plaque-forming assay and in a subcutaneous inoculation test in mice. Using the results of cell infection assays and phospholipase activities, the low-virulence strains were assigned to one of four groups by cluster analysis and then virulence-related genes were sequenced. Group I included 11 strains that did not enter cells and had no phospholipase activity. These strains exhibited a mutated PrfA; eight strains had a single amino acid substitution, PrfAK220T, and the other three had a truncated PrfA, PrfADelta174-237. These genetic modifications could explain the low virulence of group I strains, since mutated PrfA proteins were inactive. Group II and III strains entered cells but did not form plaques. Group II strains had low phosphatidylcholine phospholipase C activity, whereas group III strains had low phosphatidylinositol phospholipase C activity. Several substitutions were observed for five out of six group III strains in the plcA gene and for one out of three group II strains in the plcB gene. Group IV strains poorly colonized spleens of mice and were practically indistinguishable from fully virulent strains on the basis of the above-mentioned in vitro criteria. These results demonstrate a relationship between the phenotypic classification and the genotypic modifications for at least group I and III strains and suggest a common evolution of these strains within a group.
Subject(s)
Amino Acid Substitution , Bacterial Proteins/genetics , Listeria monocytogenes/classification , Listeria monocytogenes/pathogenicity , Listeriosis/pathology , Animals , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Cell Line , Evolution, Molecular , Female , Humans , Listeria monocytogenes/genetics , Listeriosis/microbiology , Mice , Molecular Sequence Data , Peptide Termination Factors/chemistry , Peptide Termination Factors/genetics , Peptide Termination Factors/metabolism , Phenotype , Sequence Analysis, DNA , Type C Phospholipases/genetics , Type C Phospholipases/metabolism , Virulence/geneticsABSTRACT
In addition to the economic consequences and threats associated with outbreaks, listeriosis remains of great public health concern, as it has one of the highest case fatality rates of all the foodborne infections (20%-30%), and has common source epidemic potential. Changes in the way food is produced, distributed and stored have created the potential for diffuse and widespread outbreaks involving many countries. In 2002, a survey was carried out to assess the need for and the feasibility of a European network on listeria infections in humans. Data on surveillance systems and laboratory methods were collected through two postal surveys sent to the national Centres for communicable disease surveillance and to the listeria reference laboratories. Surveillance systems for listeria infections were in operation in 16 out of the 17 countries surveyed, and 16 countries had a national reference laboratory (NRL). All countries based their case definition of listeriosis on the isolation of Listeria monocytogenes. Fourteen NRLs performed at least one typing method on human strains. At least 13 countries already carried out or expressed willingness to carry out characterisation of isolates by pulsed field gel electrophoresis (PFGE) of L. monocytogenes strains isolated from human cases following a standard protocol. The participants concluded that there was a clear added value to having a European surveillance network for listeria infections, particularly for outbreak detection and investigation, and that a surveillance network based on the existing national surveillance systems was feasible.
ABSTRACT
In the present study, we analyzed the phenotypic alterations induced by several allergens on immature dendritic cells (DC), with the aim to develop a potential in vitro alternative for predicting the sensitizing potential of chemicals. DC were generated from human monocytes cultured in the presence of GM-CSF, IL-4 and TGF-beta1 and treated for 2 or 4 days with different chemicals. Surface marker expression (HLA-DR, CD1a, CD40, CD54, CD83, CD86, CCR7 and E-cadherin) was analyzed by flow cytometry. Results showed that a 2-day treatment with the representative allergens DNCB and NiSO(4) induced significant changes of most antigens while other chemicals such as balm of Peru (strong allergen), kathon (moderate allergen), cinnamic aldehyde (mild allergen) or the irritant SLS had no significant effect. In contrast, the 4-day treatment with allergens substantially improved the results. Indeed, despite a large variability according to the donors, the number of modified antigens was significantly higher with all the tested chemicals, except kathon, as compared to that observed with the irritant SLS. The present study indicates that, in this model, the screening of mild or moderate allergens requires both the consideration of many antigens and a prolonged time of incubation with the chemicals.
Subject(s)
Allergens/adverse effects , Antigens, Surface/analysis , Dendritic Cells/physiology , Cell Culture Techniques , Cytokines/pharmacology , Drug Evaluation, Preclinical , Forecasting , Humans , Immunization , Monocytes/immunology , PhenotypeABSTRACT
Several reports have described Listeria monocytogenes strains which were nonpathogenic or weakly pathogenic, but little is known about these low-virulence strains. We found that 9 field L. monocytogenes strains were hypovirulent and 17 were avirulent, based on the number of mice contaminated and the colonization of their spleens after subcutaneous inoculation. All these strains possessed the known virulence genes. We have now assessed the low virulence of these strains in other assays before determining how they differ from virulent strains. We have shown that the low-virulence strains exhibited a phenotypic stability and were not a mixture of virulent and avirulent bacteria. They did not recover virulence after many passages in mice and colonized the spleens of mice more poorly than virulent strains after i.v. inoculation. Their lethal capacities, determined by 50% lethal dose (LD(50)), were lower than those of virulent strains. Like Listeria innocua, 14 of 17 avirulent strains had no LD(50) and were eliminated by the lymph nodes after subcutaneous inoculation. The virulent, hypovirulent, and avirulent strains were always significantly different, whatever the tests of virulence used, confirming the importance of these low-virulence field strains in identifying the proteins involved in virulence.
Subject(s)
Listeria monocytogenes/pathogenicity , Animals , Female , HT29 Cells , Humans , Lethal Dose 50 , Mice , Mice, Inbred DBA , Spleen/microbiology , VirulenceABSTRACT
Defensins have been identified as key elements of innate immunity against microbial infections. In the present study, human beta-defensin-2 (hBD-2) mRNA and peptide expression were evaluated by RT-PCR and Western blotting in normal human keratinocytes, in function of their stage of differentiation. In proliferating, non-differentiating keratinocytes generated in serum-free, low-calcium medium, a very low hBD-2 mRNA expression was found. A significantly higher expression was detected in high-calcium cultivated keratinocytes grown either as monolayers or as multilayers under submerged conditions. In an air-liquid interface culture of keratinocytes, allowing epidermis to be reconstructed, hBD-2 mRNA expression level was significantly higher than in the other conditions and displayed inter-individual variability as observed in native epidermis. The peptide was detected only in reconstructed epidermis. These results indicate that hBD-2 gene expression in normal human keratinocytes is dependent upon their stage of differentiation. The level of expression of hBD-1 mRNA was lower and that of hBD-3 was higher than that of hBD-2 in reconstructed epidermis. Exposure of reconstructed epidermis to bacterial lipopolysaccharide (LPS) resulted in an average 4-fold increase in hBD-2 mRNA 18 h after challenge, but not of hBD-1 and hBD-3 gene expression. These results show the selective regulation of hBD-2-encoding gene in an organotypic epidermal model, in response to LPS. They also provide evidence that in vitro reconstructed epidermis represents a useful model for studying regulation of expression of beta-defensins after skin challenge with pathogenic microorganisms in conditions as close as possible to the in vivo situation.