scholarly journals Expression of Peptidoglycan-Associated Lipoprotein Is Required for Virulence in the Human Model of Haemophilus ducreyi Infection

2000 ◽  
Vol 68 (11) ◽  
pp. 6441-6448 ◽  
Author(s):  
Kate R. Fortney ◽  
Royden S. Young ◽  
Margaret E. Bauer ◽  
Barry P. Katz ◽  
Antoinette F. Hood ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Confidence Interval ◽  
Formation Rate ◽  
The Other ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Suicide Vector ◽  
Inoculation Site ◽  
Human Volunteers ◽  
Similar Growth

ABSTRACT Haemophilus ducreyi expresses a peptidoglycan-associated lipoprotein (PAL) that exhibits extensive homology to Haemophilus influenzae protein 6. We constructed an isogenic PAL mutant (35000HP-SMS4) by the use of a suicide vector that contains lacZ as a counterselectable marker. H. ducreyi 35000HP-SMS4 and its parent, 35000HP, had similar growth rates in broth and similar lipooligosaccharide profiles. 35000HP-SMS4 formed smaller, more transparent colonies than 35000HP and, unlike its parent, was hypersensitive to antibiotics. Complementation of the mutant in trans restored the parental phenotypes. To test whether expression of PAL is required for virulence, nine human volunteers were experimentally infected. Each subject was inoculated with two doses (41 to 89 CFU) of live 35000HP and one dose of heat-killed bacteria on one arm and with three doses (ranging from 28 to 800 CFU) of live 35000HP-SMS4 on the other arm. Papules developed at similar rates at sites inoculated with the mutant or parent but were significantly smaller at mutant-inoculated sites than at parent-inoculated sites. The pustule formation rate was 72% (95% confidence interval [CI], 46.5 to 90.3%) at 18 parent sites and 11% (95% CI, 2.4 to 29.2%) at 27 mutant sites (P < 0.0001). The rates of recovery of H. ducreyi from surface cultures were 8% (n = 130; 95% CI, 4.3 to 14.6%) for parent-inoculated sites and 0% (n = 120; 95% CI, 0.0 to 2.5%) for mutant-inoculated sites (P < 0.001). H. ducreyi was recovered from six of seven biopsied parent-inoculated sites and from one of three biopsied mutant-inoculated sites. Confocal microscopy confirmed that the bacteria present in a mutant inoculation site pustule lacked a PAL-specific epitope. Although biosafety regulations precluded our testing the complemented mutant in humans, these results suggest that expression of PAL facilitates the ability of H. ducreyi to progress to the pustular stage of disease.

scholarly journals A DltA Mutant of Haemophilus ducreyi Is Partially Attenuated in Its Ability To Cause Pustules in Human Volunteers

2006 ◽  
Vol 74 (2) ◽  
pp. 1394-1397 ◽  
Author(s):  
Diane Janowicz ◽  
Isabelle Leduc ◽  
Kate R. Fortney ◽  
Barry P. Katz ◽  
Christopher Elkins ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Human Serum ◽  
Parent Strain ◽  
Outer Membrane Proteins ◽  
The Other ◽  
Haemophilus Ducreyi ◽  
Serum Resistance ◽  
Human Volunteers ◽  
Serum Killing ◽  
Normal Human

ABSTRACT Haemophilus ducreyi produces two outer membrane proteins, called DltA (H. ducreyi lectin A) and DsrA (H. ducreyi serum resistance A), that contribute to the ability of the organism to evade complement-mediated serum killing. In contrast to their isogenic parent strain, 35000HP, the DsrA mutant FX517 exhibits 0% survival in 50% normal human serum and the DltA mutant FX533 exhibits 23% survival. Compared to 35000HP, FX517 does not cause pustule formation in human volunteers. To test whether DltA was required for virulence in humans, seven volunteers were experimentally infected with 35000HP and FX533. Four subjects were inoculated with fixed doses of 35000HP (101 CFU or 130 CFU) at three sites on one arm and escalating doses of FX533 (range, 46 CFU to 915 CFU) at three sites on the other arm. Pustules only developed at mutant-injected sites at doses nearly twofold higher than that of the parent, suggesting that FX533 was partially attenuated. Three subjects were inoculated with similar doses of the parent (67 CFU) and mutant (104 CFU) at three sites. Pustules formed at five of nine parent sites and one of nine mutant sites. Overall, the papule and pustule formation rates for 35000HP and FX533 were similar for the trial. However, for the five subjects who received similar doses of the parent and mutant, pustules developed at 7 of 15 sites (46.7%; 95% confidence interval [CI], 16.9% to 76.5%) inoculated with the parent and at 1 of 15 (6.7%; 95% CI, 0.1% to 18.4%) sites inoculated with the mutant (P = 0.043). We concluded that the DltA mutant was attenuated in its ability to cause disease at doses similar to that of the parent.

scholarly journals DsrA-Deficient Mutant of Haemophilus ducreyi Is Impaired in Its Ability To Infect Human Volunteers

2001 ◽  
Vol 69 (3) ◽  
pp. 1488-1491 ◽  
Author(s):  
Cliffton T. H. Bong ◽  
Robert E. Throm ◽  
Kate R. Fortney ◽  
Barry P. Katz ◽  
Antoinette F. Hood ◽  
...  
Keyword(s):  
Human Subjects ◽  
Formation Rate ◽  
The Other ◽  
Haemophilus Ducreyi ◽  
Surface Areas ◽  
Resistant Phenotype ◽  
Human Volunteers ◽  
Normal Human ◽  
In Trans

ABSTRACT Haemophilus ducreyi produces an outer membrane protein called DsrA, which is required for serum resistance. An isogenicdsrA mutant, FX517, was constructed previously in H. ducreyi 35000. Compared to its parent, FX517 cannot survive in normal human serum. When complemented in trans with a plasmid containing dsrA, FX517 is converted to a serum-resistant phenotype (C. Elkins, K. J. Morrow, Jr., and B. Olsen, Infect. Immun. 68:1608–1619, 2000). To test whetherdsrA was transcribed in vivo, we successfully amplified transcripts in five biopsies obtained from four experimentally infected human subjects. To test whether DsrA was required for virulence, six volunteers were experimentally infected with 35000 and FX517 and observed for papule and pustule formation. Each subject was inoculated with two doses (70 to 80 CFU) of live 35000 and 1 dose of heat-killed bacteria on one arm and with three doses (ranging from 35 to 800 CFU) of live FX517 on the other arm. Papules developed at similar rates at sites inoculated with the mutant or parent. However, mutant papule surface areas were significantly smaller than parent papules. The pustule formation rate was 58% (95% confidence interval [CI] of 28 to 85%) at 12 parent sites, and 0% (95% CI of 0 to 15%) at 18 mutant sites (P = 0.0004). Although biosafety regulations precluded our testing the complemented mutant in humans, these results suggest that expression of DsrA facilitates the ability of H. ducreyi to progress to the pustular stage of disease.

scholarly journals Haemophilus ducreyi SapA Contributes to Cathelicidin Resistance and Virulence in Humans

2010 ◽  
Vol 78 (3) ◽  
pp. 1176-1184 ◽  
Author(s):  
Kristy L. B. Mount ◽  
Carisa A. Townsend ◽  
Sherri D. Rinker ◽  
Xiaoping Gu ◽  
Kate R. Fortney ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Mutant Strain ◽  
Virulence Factor ◽  
Formation Rate ◽  
Resistance Mechanism ◽  
Bacterial Virulence ◽  
Haemophilus Ducreyi ◽  
Wild Type ◽  
Human Volunteers ◽  
Antimicrobial Peptide Resistance

ABSTRACT Haemophilus ducreyi is an extracellular pathogen of human epithelial surfaces that resists human antimicrobial peptides (APs). The organism's genome contains homologs of genes sensitive to antimicrobial peptides (sap operon) in nontypeable Haemophilus influenzae. In this study, we characterized the sap-containing loci of H. ducreyi 35000HP and demonstrated that sapA is expressed in broth cultures and H. ducreyi-infected tissue; sapA is also conserved among both class I and class II H. ducreyi strains. We constructed a nonpolar sapA mutant of H. ducreyi 35000HP, designated 35000HPsapA, and compared the percent survival of wild-type 35000HP and 35000HPsapA exposed to several human APs, including α-defensins, β-defensins, and the cathelicidin LL-37. Unlike an H. influenzae sapA mutant, strain 35000HPsapA was not more susceptible to defensins than strain 35000HP was. However, we observed a significant decrease in the survival of strain 35000HPsapA after exposure to LL-37, which was complemented by introducing sapA in trans. Thus, the Sap transporter plays a role in resistance of H. ducreyi to LL-37. We next compared mutant strain 35000HPsapA with strain 35000HP for their ability to cause disease in human volunteers. Although both strains caused papules to form at similar rates, the pustule formation rate at sites inoculated with 35000HPsapA was significantly lower than that of sites inoculated with 35000HP (33.3% versus 66.7%; P = 0.007). Together, these data establish that SapA acts as a virulence factor and as one mechanism for H. ducreyi to resist killing by antimicrobial peptides. To our knowledge, this is the first demonstration that an antimicrobial peptide resistance mechanism contributes to bacterial virulence in humans.

scholarly journals Haemophilus ducreyi Associates with Phagocytes, Collagen, and Fibrin and Remains Extracellular throughout Infection of Human Volunteers

2001 ◽  
Vol 69 (4) ◽  
pp. 2549-2557 ◽  
Author(s):  
Margaret E. Bauer ◽  
Michael P. Goheen ◽  
Carisa A. Townsend ◽  
Stanley M. Spinola
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Optical Sectioning ◽  
End Point ◽  
Transmission Electron ◽  
Human Volunteers ◽  
Kinetics Of ◽  
Phagocytic Killing

ABSTRACT In a previous study, Haemophilus ducreyi was found in the pustule and dermis of samples obtained at the clinical end point in the human model of infection. To understand the kinetics of localization, we examined infected sites at 0, 24, and 48 h after inoculation and at the clinical end point. Immediately after inoculation, bacteria were found predominantly in the dermis but also in the epidermis. Few bacteria were detectable at 24 h; however, by 48 h, bacteria were readily seen in the pustule and dermis.H. ducreyi was associated with polymorphonuclear leukocytes and macrophages in the pustule and at its base, but was not associated with T cells, Langerhans' cells, or fibroblasts.H. ducreyi colocalized with collagen and fibrin but not laminin or fibronectin. Association with phagocytes, collagen, and fibrin was seen as early as 48 h and persisted at the pustular stage of disease. Optical sectioning by confocal microscopy and transmission electron microscopy both failed to demonstrate intracellular H. ducreyi. These data identify collagen and fibrin as potentially important targets of adherence in vivo and strongly suggest that H. ducreyi remains extracellular throughout infection and survives by resisting phagocytic killing in vivo.

Occupant pre-crash kinematics in rotated seat arrangements

2021 ◽  
pp. 095440702110045
Author(s):  
Alexander Diederich ◽  
Christophe Bastien ◽  
Karthikeyan Ekambaram ◽  
Alexis Wilson
Keyword(s):  
State Of The Art ◽  
The Other ◽  
Human Model ◽  
Multi Objective ◽  
Emergency Braking ◽  
Seating Arrangement ◽  
Current State ◽  
Occupant Comfort ◽  
Occupant Kinematics ◽  
Belt System

The introduction of automated L5 driving technologies will revolutionise the design of vehicle interiors and seating configurations, improving occupant comfort and experience. It is foreseen that pre-crash emergency braking and swerving manoeuvres will affect occupant posture, which could lead to an interaction with a deploying airbag. This research addresses the urgent safety need of defining the occupant’s kinematics envelope during that pre-crash phase, considering rotated seat arrangements and different seatbelt configurations. The research used two different sets of volunteer tests experiencing L5 vehicle manoeuvres, based in the first instance on 22 50th percentile fit males wearing a lap-belt (OM4IS), while the other dataset is based on 87 volunteers with a BMI range of 19 to 67 kg/m2 wearing a 3-point belt (UMTRI). Unique biomechanics kinematics corridors were then defined, as a function of belt configuration and vehicle manoeuvre, to calibrate an Active Human Model (AHM) using a multi-objective optimisation coupled with a Correlation and Analysis (CORA) rating. The research improved the AHM omnidirectional kinematics response over current state of the art in a generic lap-belted environment. The AHM was then tested in a rotated seating arrangement under extreme braking, highlighting that maximum lateral and frontal motions are comparable, independent of the belt system, while the asymmetry of the 3-point belt increased the occupant’s motion towards the seatbelt buckle. It was observed that the frontal occupant kinematics decrease by 200 mm compared to a lap-belted configuration. This improved omnidirectional AHM is the first step towards designing safer future L5 vehicle interiors.

scholarly journals Transcription of Candidate Virulence Genes ofHaemophilus ducreyi during Infection of Human Volunteers

2001 ◽  
Vol 69 (3) ◽  
pp. 1483-1487 ◽  
Author(s):  
Robert E. Throm ◽  
Stanley M. Spinola
Keyword(s):  
Experimental Infection ◽  
Virulence Genes ◽  
Human Model ◽  
Specific Gene ◽  
Gene Products ◽  
Virulence Determinants ◽  
Reverse Transcription Pcr ◽  
Human Volunteers

ABSTRACT Haemophilus ducreyi expresses several putative virulence factors in vitro. Isogenic mutant-to-parent comparisons have been performed in a human model of experimental infection to examine whether specific gene products are involved in pathogenesis. Several mutants (momp, ftpA, losB, lst, cdtC, and hhdB) were as virulent as the parent in the human model, suggesting that their gene products did not play a major role in pustule formation. However, we could not exclude the possibility that the gene of interest was not expressed during the initial stages of infection. Biopsies of pustules obtained from volunteers infected with H. ducreyiwere subjected to reverse transcription-PCR. Transcripts corresponding to momp, ftpA, losB, lst, cdtB, and hhdA were expressed in vivo. In addition, transcripts for other putative virulence determinants such as ompA2, tdhA, lspA1, andlspA2 were detected in the biopsies. These results indicate that although several candidate virulence determinants are expressed during experimental infection, they do not have a major role in the initial stages of pathogenesis.

Humor Styles in Marriage: How Similar Are Husband and Wife?

2018 ◽  
Vol 122 (6) ◽  
pp. 2331-2347
Author(s):  
Meng-Ning Tsai ◽  
Ching-Lin Wu ◽  
Yu-Lin Chang ◽  
Hsueh-Chih Chen
Keyword(s):  
Confidence Interval ◽  
Multilevel Modeling ◽  
Married Couples ◽  
Past Research ◽  
The Other ◽  
Humor Styles ◽  
Cohen’S D ◽  
Humor Style ◽  
Valid Predictor ◽  
Cohen's D

Past research found that similar appreciation for humor exists between spouses, but it is not certain whether this similarity between spouses also exists in kindhearted or malicious humor. The present study investigated the similarity of Taiwanese married couples’ humor styles. Participants included 239 couples (mean age = 42.9 years) who had been married to each other for at least 10 years. We used a traditional Chinese edition of the Humor Styles Questionnaire to measure the humor style and clustered participants’ humor styles in order to examine the similarity between spouses. The results show that husbands have higher tendencies toward aggressive (Cohen’s d = 0.29, p < .01) and self-defeating (Cohen’s d = 0.35, p < .01) humor styles than wives. Results from multilevel modeling indicate that spouses’ aggressive ( p < .001, confidence interval = .17, .41) and self-defeating ( p < .01, confidence interval = .05, .30) humor styles acting as a valid predictor to the other spouses’ negative humor styles. Furthermore, the results show that personal humor styles could be categorized into four clusters: positive humor endorsers, negative humor endorsers, general humor endorsers, and humor deniers. According to the clusters within spouse pairs, results show that similarities in humor styles exist between spouses (χ2 = 16.73, p = .01). The current study finds that most couples have similar humor styles and that a high proportion of married couples share the same humor clusters.

scholarly journals Advanced processing and analysis of conventional confocal microscopy generated scanning FCS data

2017 ◽  
Author(s):  
Dominic Waithe ◽  
Falk Schneider ◽  
Jakub Chojnacki ◽  
Mathias Clausen ◽  
Dilip Shrestha ◽  
...  
Keyword(s):  
Confocal Microscopy ◽  
Spatial Heterogeneity ◽  
Fluorescence Correlation Spectroscopy ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Correlation Spectroscopy ◽  
The Other ◽  
Statistical Accuracy ◽  
Fluorescence Correlation ◽  
Diffusion Dynamics

AbstractScanning Fluorescence Correlation Spectroscopy (scanning FCS) is a variant of conventional point FCS that allows molecular diffusion at multiple locations to be measured simultaneously. It enables disclosure of potential spatial heterogeneity in molecular diffusion dynamics and also the acquisition of a large amount of FCS data at the same time, providing large statistical accuracy. Here, we optimize the processing and analysis of these large-scale acquired sets of FCS data. On one hand we present FoCuS-scan, scanning FCS software that provides an end-to-end solution for processing and analysing scanning data acquired on commercial turnkey confocal systems. On the other hand, we provide a thorough characterisation of large-scale scanning FCS data over its intended time-scales and applications and propose a unique solution for the bias and variance observed when studying slowly diffusing species. Our manuscript enables researchers to straightforwardly utilise scanning FCS as a powerful technique for measuring diffusion across a broad range of physiologically relevant length scales without specialised hardware or expensive software.

scholarly journals Passive Immunization with a Polyclonal Antiserum to the Hemoglobin Receptor of Haemophilus ducreyi Confers Protection against a Homologous Challenge in the Experimental Swine Model of Chancroid

2011 ◽  
Vol 79 (8) ◽  
pp. 3168-3177 ◽  
Author(s):  
Isabelle Leduc ◽  
William G. Fusco ◽  
Neelima Choudhary ◽  
Patty A. Routh ◽  
Deborah M. Cholon ◽  
...  
Keyword(s):  
Lipid A ◽  
Polyclonal Antibodies ◽  
Passive Immunization ◽  
Etiologic Agent ◽  
Polyclonal Antiserum ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Swine Model ◽  
Content Type ◽  
Monophosphoryl Lipid A

ABSTRACTHaemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired byH. ducreyifrom its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome ofH. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface ofH. ducreyiand partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against anH. ducreyiinfection, possibly by preventing acquisition of the essential nutrient heme.

The Real Relationship

2019 ◽  
pp. 351-378
Author(s):  
Charles J. Gelso ◽  
Dennis M. Kivlighan ◽  
Rayna D. Markin
Keyword(s):  
Confidence Interval ◽  
Empirical Research ◽  
Meta Analysis ◽  
Outcome Studies ◽  
Personal Relationship ◽  
The Other ◽  
Real Relationship ◽  
The Real ◽  
Relationship Outcome ◽  
Talking Cure

Although writing about the real relationship has existed from the beginnings of the talking cure,” it is only in recent years that empirical research has focused on this phenomenon. The real relationship is the personal relationship between patient and therapist marked by the extent to which each is genuine with the other and perceives/experiences the other in ways that are realistic. The strength of the real relationship is determined by both the extent to which it exists and the degree to which it is positive or favorable. In this chapter, a meta-analysis is presented on the association between the real relationship and the outcome of psychotherapy. Summed across 16 studies, this meta-analysis revealed a moderate association with outcome (r =.38, 95% confidence interval [.30, .47], p<.001, d = 0.80, N = 1,502 participants). This real relationship–outcome association was independent of the type of outcome studies and of the source of the measure. We also present frequent measures of the real relationship, limitations of the research, and patient contributions. The chapter concludes with diversity considerations and practice recommendations for developing and strengthening the real relationship.

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