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PubMedDate not supplied

Infantile chlamydial conjunctivitis. A comparison of Papanicolaou, Giemsa and immunoperoxidase staining methods.

The use of conjunctival smears to diagnose infantile Chlamydia trachomatis infection increased sixteen-fold in our hospital between the years 1979 and 1984. The present study was conducted to compare Papanicolaou and Giemsa staining methods with the avidin-biotin technique of immunostaining utilizing a highly specific antichlamydial monoclonal antibody. On retrospective review of 33 patients, chlamydial infection was diagnosed in 61% of the Papanicolaou-stained and 64% of the Giemsa-stained slides. After the Papanicolaou-stained slides were destained and immunostained with the antichlamydial antibody, round particles corresponding in size to elementary and reticulate bodies were readily seen in 79% of the cases. In comparison with the immunoperoxidase method, the sensitivity and specificity of Papanicolaou staining were 73% and 86%, respectively, while the corresponding figures for Giemsa staining were 77% and 100%, respectively. The study established the applicability of the immunoperoxidase method to this clinical condition, confirmed the accuracy of diagnoses with routine stains and highlighted the increasing incidence of chlamydial conjunctivitis in our hospital population.

Chlamydia Infections↗

PubMed1993

The adsorption staining technique applied to isolated premessenger ribonucleoprotein particles: a comparison with conventional techniques using electron microscope tomography.

A specific type of premessenger RNP particle, Balbiani ring granules from the dipteran Chironomus tentans, was biochemically isolated and visualized in three dimensions with electron microscope tomography. The particles were prepared for electron microscopy in three different ways: positively stained, negatively stained and adsorption-stained (embedded in polyvinyl alcohol, PVA, and concomitantly stained). The results were compared with those obtained for RNP particles studied in situ in ultrathin sections of plastic-embedded cells. The positively stained particles were compacted and heavily deformed with little or no internal structure. The negatively stained and the adsorption-stained particles were well preserved; the outer contours and the central cavities of the particles were outlined. The internal structure, i.e. the folded 7-nm elementary fibre, could not be recognized in the negatively stained particles. In the adsorption-stained particles, however, the fibre was discernable, although not quite as distinctly demarcated as in the plastic-embedded samples. We conclude that embedding in PVA with concomitant staining with uranyl acetate is a rapid method to obtain both good preservation and staining of isolated RNP particles. The PVA-embedded particles were also found to be sufficiently resistant to irradiation to permit a comprehensive tilt-series to be taken for electron microscope tomography.

Adsorption↗

PubMed2007

Determination of the magneto-optical relaxation of magnetic nanoparticles as a homogeneous immunoassay.

The interaction between human eotaxin (hEotaxin) and its polyclonal antibody anti-human eotaxin (anti-hEotaxin) was investigated by means of a novel liquid-phase immunoassay using the magneto-optical relaxation of ferrofluids. The binding quality as well as kinetic properties of the binding partners was determined using specifically binding magnetic probes. For this purpose, magnetic nanoparticles (MNP; DDM128N, Meito Sangyo, Japan) were initially functionalized with streptavidin. The biotin-nylated antibody was conjugated with streptavidin-MNP applying the streptavidin-biotin binding system. Binding reactions were detected by measuring the relaxation of the optical birefringence signal occurring when a pulsed magnetic field is applied to the ferrofluid. The addition of hEotaxin to anti-hEotaxin conjugated MNP in different amounts yielded an enlargement of the mean relaxation time due to the formation of MNP aggregates. In order to express the observed increase of the particles' effective diameter in terms of elementary kinetic processes between antigen and antibody, a kinetic model was introduced. Here, the binding reactions are described by a process of stepwise polymerization. The obtained results were compared with data received from surface plasmon resonance biosensor analysis, a standard tool for biomolecular interaction analysis.

Antibodies↗

PubMed2002

Computer simulations of a two-dimensional system with competing interactions.

The results and methodology of large scale computer simulations of the two-dimensional dipolar Ising model with long-range interactions are reported. Systems as large as 117,649 particles were studied to elucidate the elementary excitations and phase diagram of two-dimensional systems, such as Langmuir monolayers, thin garnet films, and adsorbed films on solid surfaces, which spontaneously form patterns of stripes, bubbles, and intermediately shaped domains. The challenging numerical investigations of large scale systems with long-range interactions at low temperatures were made possible by combining the fast multipole method and a non-Metropolis Monte Carlo sampling technique. Our simulations provide evidence that, at sufficiently high ratios of the repulsive to the attractive coupling constant for the model, twofold stripe order in the systems of interest is lost through a defect-mediated mechanism. Heat capacity data and the excitations observed in our simulations as the system disorders indicate that it is most likely an instance of a Kosterlitz-Thouless phase transition. The results from simulations with and without external field are in excellent agreement with the predictions of an analytic scaling theory [A. D. Stoycheva and S. J. Singer, Phys. Rev. E 64, 016118 (2001)], confirming the phase diagram furnished by the analytic model. The scaling theory suggests that, under certain conditions, defect-mediated stripe melting may be supplanted by Ising like disordering within stripes for small repulsion strength. A qualitative discussion of a model that supports both disordering mechanisms is presented.

Journal Article↗

PubMed1983

[The applicability of pions to cancer radiotherapy. II. Theoretical analysis of the capture and absorption of pions in polymer].

A theoretical analysis was attempted to give a remaining number of pi meson, N(X), as function of depth X in a target, lucite as model, under a beam of pi meson. Under the assumption of three different elementary processes, pi-e Rutherford scattering, pi-decay and pi-nucleus interaction, N (X) was theoretically evaluated. It was shown that the estimated stopped points of pi particles agreed well with the experimentally obtained data if the pi-e Rutherford scattering were the main cause of pi momentum reduction. Since the decay of pi meson is negligible in the reduction of pi meson, N (X) is mainly due to pi-nucleus reaction in the region of a small depth but it is due to pi-nucleus Rutherford scattering at a point less than 1.5 cm before the stopped point of pi.

Elementary Particles↗

PubMed1975

On the deposition of unipolarly charged particles in the human respiratory tract.

The effect of unipolar electrostatic charges on the total deposition efficiency in the human respiratory tract has been investigated. Monodisperse carnauba wax particles of diameter between 0.3 and 1.1 micron were charged, in a corona discharge apparatus, with a number of elementary charges ranging from about 30 to 110 per particle, with a narrow distribution. The experiments were performed with volunteers breathing through the mouth at 12 resp/min at constant flow rate, without pauses. The increase in deposition was of the order of 15 to 30% relative to neutral but otherwise unchanged monodisperse aerosol. The increase depended on the charges carried by each particle, but was independent of the concentration. Therefore it may be concluded that the variation can be ascribed to the effect of electrostatic attraction between the particle charge and the image charge on the airway wall.

Adult↗

PubMed1996

Accelerated development of genital Chlamydia trachomatis serovar E in McCoy cells grown on microcarrier beads.

Chlamydia trachomatis serovar E is a major cause of bacterially-acquired sexually transmitted infections. Stock cultures of these obligate intracellular bacteria are often propogated in McCoy cells. We recently reported that greater infectious titers of chlamydiae could be obtained if the McCoy cells were cultured on collagen-coated microcarrier beads versus plastic flasks, although the reason for the difference in efficiency was not clear. This study analyzed the development of C. trachomatis grown in McCoy cells by the two methods. Transmission electron microscopy analysis revealed an accelerated chlamydial development, with maturation of reticulate bodies into elementary bodies sooner in McCoy cells grown on the porous substratum. Comparison of particle counts versus infectivity titers indicated the production of fewer numbers of elementary bodies but which were highly infectious sooner from the infected McCoy cell-microcarrier bead cultures than from duplicate infected McCoy cell cultures grown in plastic tissue culture flasks.

Animals↗

PubMed2006

Flocculation and percolation in reversible cluster-cluster aggregation.

Off-lattice dynamic Monte-Carlo simulations were done of reversible cluster-cluster aggregation for spheres that form rigid bonds at contact. The equilibrium properties were found to be determined by the life time of encounters between two particles (te). te is a function not only of the probability to form or break a bond, but also of the elementary step size of the Brownian motion of the particles. In the flocculation regime the fractal dimension of the clusters is df=2.0 and the size distribution has a power law decay with exponent tau=1.5. At larger values of te transient gels are formed. Close to the percolation threshold the clusters have a fractal dimension df=2.7 and the power law exponent of the size distribution is tau=2.1. The transition between flocculation and percolation occurs at a characteristic weight average aggregation number that decreases with increasing volume fraction.

Journal Article↗

PubMed1975

[New data on the structure and the budding of FV3 (frog virus 3) (author's transl)].

The freeze-etching technique when applied to FV3 suspensions revealed the perfectly icosahedral structure of the viral nucleocapsids. This allowed a fine substructure suggesting the existence of numerous subunits of small dimensions to be detected at their surface. Observations of the replicas of infected cells obtained by freeze-etching revealed modifications of the external face of the cytoplasmic membrane occurring at the level of the budding viral particles; in these zones parallel stripes appeared, whose elementary structure is constant (13,5 nm). Observations of the infected cells with the scanning microscope enabled the spreading of the budding process on all the cells of a same culture to be studied. By counting the number of budding particles per mum2, it was possible to demonstrate the heterogeneity of the budding process at the surface of the cells.

Animals↗

PubMed2003

[Chlamydia-like and coronavirus-like agents found in dead cases of atypical pneumonia by electron microscopy].

OBJECTIVE: To explore the causative agents of the atypical pneumonia (also SARS) occurred recently in some regions of our country. METHOD: Organ samples of 7 dead cases of SARS were collected from Guangdong, Shanxi, Sichuan Provinces and Beijing for electron microscopic examination. 293 cell line was inoculated with the materials derived from the lungs to isolate causative agent(s). The agents in the organs and cell cultures were revealed by immunoassay. RESULTS: Both Chlamydia-like and coronavirus-like particles were found in EM. Inclusion bodies containing elementary bodies, reticulate antibodies and intermediate bodies of Chlamydia-like agent were visualized in multiple organs from the 7 dead cases, including lungs (7 cases), spleens (2 cases), livers (2 cases), kidneys (3 cases) and lymph nodes (1 cases), by ultrathin section electron microscopy (EM). In some few sections, coronavirus-like particles were concurrently seen. A coronavirus RNA- polymerase segment (440 bp) was amplified from the lung tissues of two cases of the SARS. After inoculated with materials from the lung samples, the similar Chlamydia-like particles were also found in the inoculated 293 cells. Since the Chlamydia-like agents visualized in both organs and cell cultures could not react with the genus specific antibodies against Chlamydia and monoclonal antibodies against C. pneumoniae and C. psittaci, the results might well be suggestive of a novel Chlamydia-like agent. CONCLUSION: Since the novel Chlamydia-like agent was found co-existing with a coronavirus-like agent in the dead cases of SARS, it looks most likely that both the agents play some roles in the disease. At the present time, however, one can hardly determining how did these agents interact each other synergetically, or one follows another, need further study.

Chlamydia↗

PubMed1989

Chlamydia trachomatis and parainfluenza 2 virus: a shared antigenic determinant?

A tracheal aspirate from which parainfluenza 2 (PI-2) virus but not chlamydiae was isolated demonstrated positive immunofluorescence of elementary body- and reticulate body-like particles on direct examination with anti-chlamydia monoclonal antibodies (Syva Co.). In subsequent studies, we found this reagent to show specific staining of this strain of PI-2 as well as of 3 of 18 additional PI-2 strains that were evaluated.

Antigens, Viral↗

PubMedDate not supplied

[Chlamydiae. 1].

Throughout the animal kingdom the Chlamydiae are among the most common and ancient pathogens, but only in the 1966 they were classified by Page in the same genus because of different nosological pictures that they cause, while more recently were identified as bacteria. Chlamydiae have been divided into two species: C. trachomatis and C. psittaci. In 1986 Grayston et al. proved the etiological role of a "new chlamydial strain", named TWAR (Taiwan-Acute Respiratory), in human pneumonia and bronchitis; TWAR is distinguishable from other Chlamydiae and possibly represents a new entity. The Chlamydiae are non-motile, metabolically poor bacteria, completely lacking of any enzimatic system for energy production (ATP) and for this reason are obligate intracellular parasites; they poses group-specific, species-specific and type-specific antigens. Four series of surface proteins were identified as responsible for their pathogenic properties, while many Authors consider a particular lipopolysaccharidical acid, group antigen, as a real LPS. These bacteria poses an unique developmental cycle with production of two type of particles different for metabolic and infecting characters: elementary body and reticulate body. The Chlamydiae have a broad spectrum of host. They cause persistent or chronic infections and their survival is insured by the elementary body. The Chlamydiae stimulate the humoral and the cellular-mediate immunity system and are capable of survival in the monocytes and macrophages.

Adult↗

PubMed1963

Electron microscope studies on salivary gland cells. I. The nucleus of Bradysia mycorum Frey (Sciaridae), with special reference to the nucleolus.

Salivary glands were fixed in cold 1 per cent osmium tetroxide in veronal-acetate buffer containing sucrose and embedded in methacrylate mixture or Araldite. The salivary gland nuclei of sciarids show a continuous production of nucleoli, which remain multiple and not consolidated into a single structure. The earliest recognizable nucleoli, which we call "elementary nucleoli," are aggregations of a few paired 40 A fibrils and a few 150 A particles, at many points within chromosome bands. Further development consists of the detachment of the elementary nucleoli from their points of origin and their subsequent mutual coalescence. As a result, dense patches of nucleolar material are formed which become large nucleoli at the surface of chromosomes, either attached to the band or free. The fully formed nucleoli have a characteristic dual structure with a narrow dense periphery and a broader less dense internum. Fibrils and particles are present in both regions, and the difference in density reflects differences in the packing of the two structural elements. The duality in structure is lost in later stages. The nucleolar fibrils appear to be similar to the chromosomal fibrils. The 150 A particles in nucleoli, chromosomes, and nuclear sap seem identical. The significance of these observations is discussed for nucleologenesis in general.

Cell Nucleolus↗

PubMed1985

Electron microscopic observations concerning the in vivo uptake and release of the agent of guinea-pig inclusion conjunctivitis (Chlamydia psittaci) in guinea-pig exocervix.

This report details electron-microscopical observations concerning C. psittaci infection in vivo. The model employed was that of the guinea-pig infected at the exocervical region with the agent of guinea-pig inclusion conjunctivitis (GPIC). Our observations indicate that chlamydial particles gain access to their target cells by the mechanism of endocytosis. Single GPIC elementary bodies were seen to be positioned within individual endosomes. The observations reported here provide evidence that chlamydial particles that had undergone their developmental cycle within the exocervical epithelial cells may leave the epithelium in 2 ways; within entire infected cells that had been shed into the lumen of the cervix and by means of the liberation of chlamydial particles from disrupted cells. The mechanism of cell disruption and shedding is thought to involve the large number of PMNs observed to be present within the enlarged intercellular spaces of the infected epithelium.

Animals↗

PubMed2001

Eulerian derivation of the fractional advection-dispersion equation.

A fractional advection-dispersion equation (ADE) is a generalization of the classical ADE in which the second-order derivative is replaced with a fractional-order derivative. In contrast to the classical ADE, the fractional ADE has solutions that resemble the highly skewed and heavy-tailed breakthrough curves observed in field and laboratory studies. These solutions, known as alpha-stable distributions, are the result of a generalized central limit theorem which describes the behavior of sums of finite or infinite-variance random variables. We use this limit theorem in a model which sums the length of particle jumps during their random walk through a heterogeneous porous medium. If the length of solute particle jumps is not constrained to a representative elementary volume (REV), dispersive flux is proportional to a fractional derivative. The nature of fractional derivatives is readily visualized and their parameters are based on physical properties that are measurable. When a fractional Fick's law replaces the classical Fick's law in an Eulerian evaluation of solute transport in a porous medium, the result is a fractional ADE. Fractional ADEs are ergodic equations since they occur when a generalized central limit theorem is employed.

Computer Simulation↗

PubMed1992

The molecular biology and diagnostics of Chlamydia trachomatis.

The rapid development of biotechnological methods provides the potential of dissecting the molecular structure of microorganisms. In this review the molecular biology of chlamydia is described. The genus Chlamydia contains three species C. trachomatis, C. psittaci, and C. pneumonia which all are important human pathogens. Chlamydia is obligate intracellular bacteria with a unique biphasic life cycle. The extracellularly chlamydial elementary bodies (EB) are small, metabolic inactive, infectious particles with a tight outer cell membrane. After internalization into host cells the chlamydial structure changes, they transform to reticulated bodies (RB) which become larger, metabolically active, and start to replicate. Fourtysix hrs post infection RB reorganizes to EB followed by burst of the inclusion. The structure of the EB outer membrane differs from the membrane of gram-negative bacteria since it is highly cross-linked by S-S bridges. There are, however, also similarities to gram-negative cell walls. The chlamydial major outer membrane protein, Omp1, forms pores and is closely associated with lipopolysaccharide, LPS. LPS, however, is more loosely associated with Omp1 than in other gram negative bacteria since incubation of EB with antibodies against LPS will liberate it from the chlamydial surface. Therefore the surface localized LPS may be important for chlamydial survival. OMP1 varies between the different serovar of C. trachomatis. Several very conserved regions are separated by variable domains. The variable domains are very antigenic and are localized at the surface of EB. After chlamydial internalization into the host cell transition to RB starts. Some of the early proteins are DnaK-like and groEL-like heat-shock proteins. The chlamydial DnaK-like protein is very antigenic. Patient serum samples will recognize the chlamydial DnaK-like protein. From the determined DNA sequence the amino acid sequence was determined. It was 57% homologous to the Eschrichia coli DnaK protein. Also the GroEL-like protein is antigenic and very conserved. Factors of importance for pathogenicity of chlamydia have not yet been found. The adhesin(s) is unknown, and no factor of importance for the inhibition of fusion between phagosome and host cell lysosomes has been described. A protein similar to the mip gene product of Legionella pneumofila may be a possible candidate for a pathogenicity factor. Diagnosis of C. trachomatis infections has been done by chlamydia cultivation in tissue culture cells, by immunofluorescence and by ELISA. A new method based on the polymerase chain reaction (PCR) has been developed. As primers sequences from the common plasmid were used. This method has high sensitivity and specificity and does not require live chlamydia.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗

PubMed1985

[Contribution of recent methods to the diagnosis of Chlamydia infections].

Chlamydia trachomatis is the most common cause of non- and/or post-gonococcal urethritis in men. The infection is often silent in women, but may be complicated by salpingitis followed by tubal sterility. The direct diagnosis: Since the availability of monoclonal antibodies, the microscopic examination of a smear of the sample is once again a current technique. By using an immuno-fluorescent technique, it is possible to demonstrate the elementary corpuscules in the form of free extracellular particles. This methods is rapid and easy to perform. Culture: Nevertheless, culture remains the reference technique despite the fact that it only reveals "inclusions": clumps of reticulated particles. The technique is simplified by using microculture in flat bottomed microtitration plates, which enables a large number of isolations to be performed in one step. The visualisation by means of monoclonal antibodies is in perfect agreement with classical staining techniques. The serological diagnosis: Micro-immuno-fluorescence (MIF) is still the reference technique. ELISA occasionally fails to correlate with MIF. These discordances can be explained by the different antigens used: protein extracts bound to a support, in the case of ELISA, and whole live particles, in the case of MIF.

Antibodies, Monoclonal↗

PubMed2002

A closer look at the elementary fermions.

Although there have been many experimental and theoretical efforts to measure and interpret small deviations from the standard model of particle physics, the gap that the model leaves in understanding why there are only three generations of the elementary fermions, with hierarchical masses, has not received the attention it deserves. I present here an attempt to fill this gap. Although our findings are mostly only qualitative, they nevertheless may be of heuristic value. Rules concerning the elementary fermions, some previously known and some new, lead to a number of conclusions and questions that seem worth pursuing. Some clarify the standard model, and others suggest possible modifications, the implications of which are discussed.

Journal Article↗