Self-balancing diffusion is a theoretical concept that restricts the introduction of extents of reactions. This concept is analyzed in detail for general mass- and molar-based balances of reaction-diffusion mixtures, in relation to non-self-balancing cases, and with respect to its practical consequences. Self-balancing is a mathematical restriction on the divergences of diffusion fluxes. Fulfilling this condition enables the proper introduction of the extents of (independent) reactions that reduce the number of independent variables in thermodynamic descriptions. A note on a recent generalization of the concept of reaction and diffusion extents is also included. Even in the case of self-balancing diffusion, such extents do not directly replace reaction rates. Concentration changes caused by reactions (not by diffusion) are properly described by rates of independent reactions, which are instantaneous descriptors. If an overall descriptor is needed, the traditional extents of reactions can be used, bearing in mind that they include diffusion-caused changes. On the other hand, rates of independent reactions integrated with respect to time provide another overall, but reaction-only-related descriptor.
- MeSH
- Diffusion * MeSH
- Kinetics MeSH
- Thermodynamics MeSH
- Publication type
- Journal Article MeSH
Understanding the mechanisms governing and regulating self-organisation in the developing embryo is a key challenge that has puzzled and fascinated scientists for decades. Since its conception in 1952 the Turing model has been a paradigm for pattern formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework of Turing models, showing how non-diffusing species impact the conditions for the emergence of self-organisation. We illustrate our results within the framework of hair follicle pre-patterning, showing how receptor interaction structures can be constrained by the requirement for patterning, without the need for detailed knowledge of the network dynamics. Finally, in the light of our results, we discuss the ability of such systems to pattern outside the classical limits of the Turing model, and the inherent dangers involved in model reduction.
- MeSH
- Models, Biological MeSH
- Cell Communication physiology MeSH
- Morphogenesis physiology MeSH
- Mice MeSH
- Hair Follicle embryology MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Primary mediastinal B-cell lymphoma (PMBL) seems to be reliably distinguished from diffuse large B-cell lymphoma (DLBCL) with microarray technology. We measured expression of Fcer2, Pdl2 and Blk genes using real-time quantitative polymerase chain reaction (RTqPCR) on formalin fixed, paraffin embedded material (FFPE) and suggested a formula to discriminate PMBL from DLBCL. For 39/82 included patients the diagnosis of PMBL was expected clinico-pathologically. Diagnosis of 10/39 and 2/43 of clinically considered PMBLs and DLBCLs, respectively, was not genetically confirmed. Compared to confirmed PMBLs, unconfirmed ones showed clinical features similar to DLBCLs, e.g. spleen infiltration (p=0,028) and decreased invasiveness in pericardium (p=0,045). They tended to have more common infradiaphragmatic involvement, less often tumor sclerosis or fluidothorax. There were no immunohistochemical differences between genetically confirmed and unconfirmed PMBLs. New approach of distinguishing PMBL and DLBCL is presented. It is based on expression of three genes in routinely available FFPE material using RTqPCR.
- MeSH
- Lymphoma, B-Cell diagnosis MeSH
- Diagnosis, Differential MeSH
- Lymphoma, Large B-Cell, Diffuse diagnosis MeSH
- Adult MeSH
- Immunohistochemistry MeSH
- Middle Aged MeSH
- Humans MeSH
- Mediastinal Neoplasms diagnosis MeSH
- Polymerase Chain Reaction methods MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Úvod a cieľ: Staphylococcus aureus je významným oportunistickým patogénom s veľmi variabilným genómom, takže je zodpovedný za široké spektrum ochorení. Významným miestom výskytu tohto patogénu u zdravých jedincov, vrátane kmeňov rezistentných voči meticilínu, je okrem iných orgánov, akými sú napr. koža, hltan, sliznica nosa apod., aj ústna dutina. Hlavným cieľom našej štúdie bolo preto zistiť, či rôzne podmienky v ústnej dutine, ako parodontitída, fixné a snímateľné protetické zubné náhrady a stomatologické ochorenia s indikáciou na extrakciu, majú vplyv na mieru kolonizácie ústnej dutiny týmto mikroorganizmom a zároveň stanoviť frekvenciu výskytu meticilín rezistentných kmeňov Staphylococcus aureus u stomatologických pacientov. Metódy: Vyšetrovaný súbor pozostával z 96 pacientov, ktorí v období od júna 2014 do januára 2015 navštívili zubnú ambulanciu LUXDENT, s.r.o., v Nitre. Súbor bol rozdelený do štyroch skupín podľa podmienok v ústnej dutine – a to do skupiny pacientov: 1. s parodontitídou, 2. so stomatologickými ochoreniami s indikáciou na extrakciu, 3. s fixnými alebo snímateľnými zubnými náhradami a 4. do kontrolnej skupiny. Pacientom sa sterilným tampónom urobili výtery z nosovej a ústnej dutiny a do 24 hodín sa transportovali do laboratória. V laboratóriu sa vzorky spracovali štandardnými metódami pre izoláciu a identifikáciu Staphylococcus aureus, s následnou konfirmáciou druhu metódou polymerázovej reťazovej reakcie, kde sa amplifikoval špecifický úsek nuc génu o veľkosti cca 270 bp, charakteristický pre tento druh mikroorganizmu. Meticilín rezistentné kmene Staphylococcus aureus sa identifikovali pomocou diskovej difúznej metódy podľa metodiky Európskeho výboru pre testovanie antimikrobiálnej citlivosti [8]. Výsledky: Prítomnosť tohto mikroorganizmu sa zistila v 35 vzorkách (20,2 %) zo 173 vyšetrených vzoriek (výtery z orálnej a nazálnej dutiny), z toho 31 vzoriek bolo na meticilín senzitívnych (88,58 %) a štyri vzorky boli voči meticilínu rezistentné (11,42 %). Medzi výskytom mikroorganizmu v nose a ústach bol štatisticky významný rozdiel (p < 0,05), s častejším výskytom v nazálnej dutine. Iba u troch z 96 pacientov (3,12 %) sa dokázala prítomnosť Staphylococcus aureus zároveň v nazálnej aj orálnej dutine. Pri porovnaní skupiny pacientov s fixnými a snímateľnými protetickými náhradami s ostatnými skupinami bol výskyt mikroorganizmu Staphylococcus aureus v tejto skupine signifikantne vyšší (p < 0,05). Závery: Naše výsledky indikovali, že orálna dutina môže byť primárne (bez súčasnej prítomnosti mikroorganizmu v nose) kolonizovaná zlatým stafylokokom a podmienky v ústnej dutine, ako napr. fixné a snímateľné zubné náhrady, môžu mať na jej kolonizáciu významný vplyv. Klíčové slova: Staphylococcus aureus – meticilín rezistentný Staphylococcus aureus – ústna dutina – parodontitída – protetické zubné náhrady
Introduction and aim: Staphylococcus aureus is a significant opportunistic pathogen possessing highly variable genome, causing thus wide range of infections. An important location where this pathogen may occur in healthy individuals includes not only organs such as skin, pharynx, nasal mucosa, etc., but also oral cavity. The main objective of our study was to find out whether various oral cavity conditions such as periodontitis, fixed and removable dental prostheses and stomatological diseases with indications for extraction influence the level of oral cavity colonization by the Staphylococcus aureus, as well as to define the frequency of occurence of methicillin-resistant strains of this microorganism in stomatological patients. Methods: The examined collection consisted of 96 patients, who attended dental services LUXDENT, Ltd., in Nitra from June 2014 to January 2015. Patients were divided into the groups studied, i.e., the group of patients with 1. periodontitis, 2. dental diseases with indications for extraction, 3. fixed or removable prosthetic restorations and 4. control group. Microbiological samples were obtained by sterile swabs from oral and nasal cavity of subjects included into study and delivered to the laboratory within 24 h. At the laboratory, samples were processed by standard methods for isolation and identification of Staphylococcus aureus and confirmed by polymerase chain reaction, in which the specific region of nuc gene, characteristic for Staphylococcus aureus was amplified. Methicillin-resistant strains of Staphylococcus aureus were identified using disc difusion method according to the methodology of the European Committee on Antimicrobial Susceptibility Testing [8]. Results: The presence of S. aureus was found in 35 samples (20.2%) out of 173 examined samples (oral and nasal cavity swabs), while 31 of those samples were methicillin-sensitive (88.58%) and four of them were methicillin-resistant (11.42%). There was a statistically important difference between the occurrence of the microorganism in nose and mouth (p < 0,05) indicating a more frequent occurrence in the nasal cavity. The presence of the microorganism in both nasal and oral cavities simultaneously was discovered only in three out of 96 patients (3.12%). When comparing the group of patients with fixed and removable prostheses to other groups, the occurrence of microorganism studied was significantly higher (p < 0,05). Conclusions: Our results indicate that the oral cavity may be an important site of Staphylococcus aureus colonisation and the conditions in the oral cavity, e.g., fixed and removable restorations may promote oral carriage of this microorganism. Keywords: Staphylococcus aureus – methicillin resistant Staphylococcus aureus – oral cavity – parodontitis – dental prostheses
- MeSH
- Disk Diffusion Antimicrobial Tests MeSH
- DNA isolation & purification MeSH
- Humans MeSH
- Nasal Mucosa * microbiology pathology MeSH
- Oral Hygiene MeSH
- Periodontitis MeSH
- Polymerase Chain Reaction MeSH
- Staphylococcus aureus * isolation & purification MeSH
- Mouth Mucosa * microbiology pathology MeSH
- Dentures MeSH
- Check Tag
- Humans MeSH
Autoři popisují případ 1 měsíc starého dítěte s herpetickou encefalitidou způsobenou poměrně málo častým původcem herpetické encefalitidy - HSV typu II. Po 5 dnech od počátku klinické symptomatologie byl normální nález při užití "rutinního" vyšetřovacího protokolu magnetickou rezonancí, ale s výrazným nálezem v DWI a ADC zobrazení (restrikce difuze). Autoři doporučují při podezření na herpetickou encefalitidu zařadit DWI a ADC zobrazení jako součást základního vyšetřovacího protokolu.
Authors report a case of one-month-old patient with herpes simplex infection, type 2. No abnormal findings were seen on conventional MRI protocol. Difusion-weighted MRI performed 5 days afer the onset of symptoms revealed restricted difusion. Authors recommend immediate, difusion-weighted MRI and ADC (apparent diffusion coeficient) maps as a standard MRI protocol, when suspicion of herpetic encephalitis exists.
- MeSH
- Acyclovir therapeutic use MeSH
- Diffusion Magnetic Resonance Imaging methods utilization MeSH
- Electroencephalography utilization MeSH
- Financing, Organized MeSH
- Encephalitis, Herpes Simplex diagnosis MeSH
- Humans MeSH
- Infant, Newborn MeSH
- Polymerase Chain Reaction methods utilization MeSH
- Check Tag
- Humans MeSH
- Infant, Newborn MeSH
- Female MeSH
- Publication type
- Case Reports MeSH
Escherichia coli can cause serious infections in the neonates and pregnant women. Although E. coli is widely studied, E. coli lactose-negative (lac-) strains have been rarely described before. So, the aim of this study was to compare lac- and lactose-positive (lac+) E. coli strains in respect of antimicrobial susceptibility and the frequency of virulence genes (VGs). The study included 58 lac+ and 58 lac- E. coli strains isolated from pregnant women and neonates. Culture and the results of biochemical reactions were conducted for lac- and lac+ E. coli identification and differentiation. Disc diffusion test was performed to study the antimicrobial susceptibility of the isolates, and PCR was used to detect VGs. Resistance to at least one of the tested antibiotics was found among 14 (25.9%) E. coli lac+ and in 26 (44.9%) E. coli lac- strains. Both lac+ and lac- E. coli strains were mostly resistant to ampicillin (22.4 and 39.7%) and ticarcillin (20.7 and 39.7%). None of the tested strains produced extended-spectrum β-lactamases (ESBLs). Genes fimH, fimA, iutA, sfa/foc, neuC, ibeA, and hlyF were detected, respectively, in 96.6, 82.8, 32.8, 24.1, 22.4, 12.1, and 6.9% of lac+ E. coli strains and in 94.8, 86.2, 48.3, 19.0, 8.6, 8.6, and 1.7% of lac- strains. The antimicrobial susceptibility and the pathogenic potential of both tested groups of E. coli strains are similar. Therefore, omitting E. coli lac- strains as a potential etiological agent of infections may pose a threat to the health and life of both mothers and neonates.
- MeSH
- Anti-Bacterial Agents pharmacology MeSH
- Drug Resistance, Bacterial MeSH
- Disk Diffusion Antimicrobial Tests MeSH
- Adult MeSH
- Escherichia coli drug effects genetics isolation & purification MeSH
- Virulence Factors analysis genetics MeSH
- Escherichia coli Infections microbiology MeSH
- Pregnancy Complications, Infectious microbiology MeSH
- Infant MeSH
- Lactose metabolism MeSH
- Humans MeSH
- Young Adult MeSH
- Infant, Newborn MeSH
- Polymerase Chain Reaction MeSH
- Bacterial Typing Techniques MeSH
- Pregnancy MeSH
- Check Tag
- Adult MeSH
- Infant MeSH
- Humans MeSH
- Young Adult MeSH
- Infant, Newborn MeSH
- Pregnancy MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
Cil práce: Posoudit výskyt antimikrobiální rezistence u kmenů L. monocytogenes izolovaných od lidi a z potravin České republiky v období let 2001 až 2012. Materiál a metody: Fenotypový projev antimikrobiálni rezistence byl monitorován diskovou difúzni metodou a doplněn stanovením minimální inhibični koncentrace metodou E-testu a genů rezistence metodou PCR. Výsledky: Všechny testované kmeny (678) byly citlivé k ampicilinu, penicilinu, gentamicinu, trimetoprimu, vankomycinu a chloramfenikolu. Ojediněle byla u kmenů pocházejících z potravin prokázána rezistence k tetracyklinu (2/509) a erytromycinu (1/509). Závěr: Ve sledovaném období byla zjištěna velmi dobrá a doposud stabilní citlivost testovaných kmenů L. monocytogenes izolovaných Z člověka i potravin k antibiotikům využívaných v terapii listerióz. Sporadický výskyt rezistence byl zaznamenán pouze u kmenů z potravin.
Background: To assess the incidence of antimicrobial resistance of L. monocytogenes strains isolated from humans and foods in the Czech Republic in the period of 2001 to 2012. Material and methods: Phenotypic resistance testing has been monitored by the disk diffusion method and complemented by the assessment of minimum inhibitory concentration by E-test method and genes encoding resistance by the PCR method. Results: All tested strains (678) were susceptible to ampicillin, penicilhn, gentamicin, trimethoprim, vancomycin and chloramphenicol. Resistance to tetracycline (2/509) and erythromycin (1/509) was detected sporadically in strains of food origin. Conclusions: Very good and so far stable susceptibility of tested strains of L. monocytogenes isolated from humans and foods to antibiotics used in the therapy of listeriosis was found in the monitoring period. Sporadic occurrence of resistance was detected only in strains from foods.
- Keywords
- humánní izoláty, izoláty z potravin, E-test,
- MeSH
- Food Analysis MeSH
- Anti-Bacterial Agents MeSH
- Disk Diffusion Antimicrobial Tests statistics & numerical data MeSH
- Value of Life MeSH
- Drug Resistance * MeSH
- Humans MeSH
- Listeria monocytogenes * isolation & purification classification drug effects MeSH
- Microbial Sensitivity Tests statistics & numerical data MeSH
- Polymerase Chain Reaction MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
- MeSH
- Blood Safety * methods MeSH
- Blood Transfusion * standards MeSH
- Humans MeSH
- Transfusion Reaction MeSH
- Disease Transmission, Infectious prevention & control MeSH
- Diffusion of Innovation MeSH
- Nucleic Acid Amplification Techniques * trends utilization MeSH
- Donor Selection standards MeSH
- Check Tag
- Humans MeSH
