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 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 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.

Bronchoprotective and bronchodilatory effects of deep inspiration in rabbits subjected to bronchial challenge

2001 ◽  
Vol 91 (6) ◽  
pp. 2511-2516 ◽  
Author(s):  
S. J. Gunst ◽  
X. Shen ◽  
R. Ramchandani ◽  
R. S. Tepper
Keyword(s):  
Human Subjects ◽  
Inhibitory Effect ◽  
Airway Responsiveness ◽  
Deep Inspiration ◽  
Contractile Apparatus ◽  
Airway Reactivity ◽  
Airway Response ◽  
Normal Human ◽  
Airway Responses

The effect of deep inspiration (DI) on airway responsiveness differs in asthmatic and normal human subjects. The mechanism for the effects of DI on airway responsiveness in vivo has not been identified. To elucidate potential mechanisms, we compared the effects of DI imposed before or during induced bronchoconstriction on the airway response to methacholine (MCh) in rabbits. The changes in airway resistance in response to intravenous MCh were continuously monitored. DI depressed the maximum response to MCh when imposed before or during the MCh challenge; however, the inhibitory effect of DI was greater when imposed during bronchoconstriction. Because immature rabbits have greater airway reactivity than mature rabbits, we compared the effects of DI on their airway responses. No differences were observed. Our results suggest that the mechanisms by which DI inhibits airway responsiveness do not depend on prior activation of airway smooth muscle (ASM). These results are consistent with the possibility that reorganization of the contractile apparatus caused by stretch of ASM during DI contributes to depression of the airway response.

scholarly journals Localization of Haemophilus ducreyi at the Pustular Stage of Disease in the Human Model of Infection

2000 ◽  
Vol 68 (4) ◽  
pp. 2309-2314 ◽  
Author(s):  
Margaret E. Bauer ◽  
Stanley M. Spinola
Keyword(s):  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Human Subjects ◽  
Haemophilus Ducreyi ◽  
Human Model ◽  
Stage Of Disease ◽  
The One ◽  
Secondary Antibodies

ABSTRACT To localize Haemophilus ducreyi in vivo, human subjects were experimentally infected with H. ducreyi until they developed a painful pustule or for 14 days. Lesions were biopsied, and biopsy samples were fixed in 4% paraformaldehyde, and cryosectioned. Sections were stained with polyclonal anti-H. ducreyi antiserum or H. ducreyi-specific monoclonal antibodies (MAbs) and fluorescently tagged secondary antibodies and examined by confocal microscopy. We identified H. ducreyi in 16 of 18 pustules but did not detect bacteria in the one papule examined. H. ducreyi was observed as individual cells and in clumps or chains. Staining with MAbs 2D8, 5C9, 3B9, 2C7, and 9D12 demonstrated that H. ducreyi expresses the major pilus subunit, FtpA, the 28-kDa outer membrane protein Hlp, the 18-kDa outer membrane protein PAL, and the major outer membrane protein (MOMP) or OmpA2 in vivo. By dual staining with polyclonal anti-H. ducreyi antiserum and MAbs that recognize human skin components, we observed bacteria within the neutrophilic infiltrates of all positively staining pustules and in the dermis of 10 of 16 pustules. We were unable to detect bacteria associated with keratinocytes in the samples examined. The data suggest that H. ducreyi is found primarily in association with neutrophils and in the dermis at the pustular stage of disease in the human model of infection.

Platelet catecholamines and platelet function in normal human subjects

1987 ◽  
Vol 73 (1) ◽  
pp. 99-103 ◽  
Author(s):  
A. P. Wilson ◽  
C. C. T. Smith ◽  
B. N. C. Prichard ◽  
D. J. Betteridge
Keyword(s):  
Platelet Function ◽  
High Performance ◽  
Human Subjects ◽  
Normal Subjects ◽  
Noradrenaline Content ◽  
Collagen Concentration ◽  
Normal Human ◽  
Wall Interaction ◽  
Local Release

1. We have used high-performance liquid chromatography with electrochemical detection to measure plasma and platelet catecholamines in 24 normal subjects. 2. In the same subjects platelet function was assessed by measuring platelet aggregation in response to adenosine 5′-pyrophosphate, thrombin, adrenaline and collagen. Platelet sensitivity to prostacyclin was also examined. 3. Platelet noradrenaline showed a positive correlation with extent of aggregation induced by ‘low-dose’ collagen (1 μg/ml). No correlation was seen at the higher collagen concentration. 4. Platelet noradrenaline content also correlated with sensitivity of platelets to prostacyclin. High platelet noradrenaline concentrations appeared to result in decreased sensitivity to prostacyclin. 5. No other correlations were observed. 6. These data suggest that platelet noradrenaline rather than plasma levels may be involved in modifying platelet function in vivo. Local release of platelet catecholamines may affect the platelet/vessel wall interaction, the primary physiological step in platelet activation.

scholarly journals Spatial nonuniformity of the resting CBF and BOLD responses to sevoflurane: In vivo study of normal human subjects with magnetic resonance imaging

2008 ◽  
Vol 29 (12) ◽  
pp. 1390-1399 ◽  
Author(s):  
Maolin Qiu ◽  
Ramachandran Ramani ◽  
Michael Swetye ◽  
Robert Todd Constable
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Human Subjects ◽  
In Vivo Study ◽  
Resonance Imaging ◽  
Spatial Nonuniformity ◽  
Bold Responses ◽  
Normal Human

scholarly journals A Superoxide Dismutase C Mutant of Haemophilus ducreyi Is Virulent in Human Volunteers

2002 ◽  
Vol 70 (3) ◽  
pp. 1367-1371 ◽  
Author(s):  
Cliffton T. H. Bong ◽  
Kate R. Fortney ◽  
Barry P. Katz ◽  
Antoinette F. Hood ◽  
Lani R. San Mateo ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Haemophilus Ducreyi ◽  
Swine Model ◽  
Bacterial Survival ◽  
Copper Zinc Superoxide Dismutase ◽  
Zinc Superoxide Dismutase ◽  
Human Volunteers ◽  
Significant Difference ◽  
Copper Zinc

ABSTRACT Haemophilus ducreyi produces a periplasmic copper-zinc superoxide dismutase (Cu-Zn SOD), which is thought to protect the organism from exogenous reactive oxygen species generated by neutrophils during an inflammatory response. We had previously identified the gene, sodC, responsible for the production and secretion of Cu-Zn SOD and constructed an isogenic H. ducreyi strain with a mutation in the sodC gene (35000HP-sodC-cat). Compared to the parent, the mutant does not survive in the presence of exogenous superoxide (L. R. San Mateo, M. Hobbs, and T. H. Kawula, Mol. Microbiol. 27:391-404, 1998) and is impaired in the swine model of H. ducreyi infection (L. R. San Mateo, K. L. Toffer, P. E. Orndorff, and T. H. Kawula, Infect. Immun. 67:5345-5351, 1999). To test whether Cu-Zn SOD is important for bacterial survival in vivo, six human volunteers were experimentally infected with 35000HP and 35000HP-sodC-cat and observed for papule and pustule formation. Papules developed at similar rates at sites inoculated with the mutant or parent. The pustule formation rates were 75% (95% confidence intervals [CI], 43 to 95%) at 12 parent-inoculated sites and 67% (95% CI, 41 to 88%) at 18 mutant-inoculated sites (P = 0.47). There was no significant difference in levels of H. ducreyi recovery from mutant- and parent-inoculated biopsy sites. These results suggest that expression of Cu-Zn SOD does not play a major role in the survival of this pathogen in the initial stages of experimental infection of humans.

scholarly journals Oxyphytosterols are present in plasma of healthy human subjects

2004 ◽  
Vol 91 (1) ◽  
pp. 101-106 ◽  
Author(s):  
André Grandgirard ◽  
Lucy Martine ◽  
Luc Demaison ◽  
Catherine Cordelet ◽  
Corinne Joffre ◽  
...  
Keyword(s):  
Human Subjects ◽  
Plasma Samples ◽  
Healthy Human ◽  
Human Samples ◽  
Human Volunteers ◽  
Healthy Human Subjects ◽  
Few Data ◽  
Derivatives Of

The oxidised derivatives of phytosterols (oxyphytosterols) were identified in plasma samples from thirteen healthy human volunteers, using MS. All the samples contained noticeable quantities of (24R)-5β,6β-epoxy-24-ethylcholestan-3β-ol (β-epoxysitostanol) and (24R)-ethylcholestan-3β,5α,6β-triol (sitostanetriol) and also trace levels of (24R)-5α,6α-epoxy-24-ethylcholestan-3β-ol (α-epoxysitostanol), (24R)-methylcholestan-3β,5α,6β-triol (campestanetriol) and (24R)-ethylch olest-5-en-3β-ol-7-one(7-ketositosterol). The amounts of these oxyphytosterols in plasma varied from 4·8 to 57·2 ng/ml. There are two possibilities concerning the origin of these compounds. First, they could come from the small amounts of oxyphytosterols in food. Second, they could originate from the in vivo oxidation of phytosterols in plasma. Very few data actually exist concerning these compounds. Their identification in human samples suggests that further research is necessary in this field.

The appearance of compound cilia in the nasal mucosa of normal human subjects following acute, in Vivo exposure to sulfur dioxide

1987 ◽  
Vol 42 (1) ◽  
pp. 155-165 ◽  
Author(s):  
Johnny L. Carson ◽  
Albert M. Collier ◽  
Shih-chin Hu ◽  
Craig A. Smith ◽  
Paul Stewart
Keyword(s):  
Sulfur Dioxide ◽  
Nasal Mucosa ◽  
Human Subjects ◽  
Normal Human

Effects of an intravenous saline load on erythrocyte sodium transport in normal human subjects

1985 ◽  
Vol 69 (6) ◽  
pp. 709-712 ◽  
Author(s):  
Roberto Boero ◽  
Francesco Quarello ◽  
Cesare Guarena ◽  
Clelia Rosati ◽  
Giuseppe Piccoli
Keyword(s):  
Sodium Transport ◽  
Human Subjects ◽  
Extracellular Fluid ◽  
Saline Infusion ◽  
Nacl Solution ◽  
Percentage Decrease ◽  
Intravenous Saline ◽  
Normal Human ◽  
Erythrocyte Sodium

1. The effects of a 2 litre intravenous infusion of saline (0.9% NaCl solution) over 3 h on erythrocyte transmembrane sodium transport were studied in 12 normal human subjects. 2. After saline infusion a significant (P < 0.01) reduction of both outward Na+, K+ pump- and Na+, K+ cotransport-mediated Na+ effluxes was observed. The Na+, Li+ countertransport rate and the passive Na+ permeability did not change. 3. The incubation of the subjects' erythrocytes, obtained on a separate occasion, with their own plasma taken after the saline infusion, induced an inhibition of both Na+, K+ pump and Na+, K+ cotransport outward sodium fluxes. The percentage decrease after incubation was closely correlated with the percentage reduction induced by the saline infusion in vivo (r = 0.93 for the pump and r = 0.96 for cotransport; P < 0.01). 4. These data suggest that extracellular fluid volume expansion affects the release of circulating factors modulating sodium transport by the Na+, K+ pump and by Na+, K+ cotransport.

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