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R Morisset

Publications and source records attributed to R Morisset.

At least 19 recordsLinked to original sources
PubMed2006

Sustained interleukin-6 and interleukin-8 expression following infection with Chlamydia trachomatis serovar L2 in a HeLa/THP-1 cell co-culture model.

Chlamydia trachomatis, an intracellular obligate bacterium, remains responsible for a large spectrum of disorders that can progress to chronic diseases, resulting in severe sequelae, such as tubal infertility and blindness. These sequelae may be due to deleterious immune responses induced by repeated or persistent infections. By initiating and regulating inflammation as well as immune responses, pro-inflammatory cytokines secreted by local infected epithelial and immune cells, such as monocytes, may play an essential role in immunity and in the immunopathogenesis of chlamydial diseases. In this study, we mimicked the in vivo interaction between epithelial cells and monocytes by co-culturing epithelial-like HeLa cells with monocyte-like THP-1 cells. Pro-inflammatory cytokines [interleukin-beta (IL-1beta), IL-6, IL-8, IL-10, IL-12p70 and tumour necrosis factor-alpha (TNF-alpha)] were measured by multiplexed cytometric bead array assay over a period of 18 days. We observed that pro-inflammatory cytokine secretion was augmented after C. trachomatis infection in HeLa and THP-1 cells. However, this heightened secretion was subsequently reduced. When infected HeLa cells were co-cultured with THP-1 cells, IL-6 and IL-8 secretion was sustained, IL-1beta expression followed a bell-shaped curve and IL-10, IL-12p70 and TNF-alpha synthesis was down regulated. IL-6 and IL-8 may be involved in the immunopathogenesis of chronic chlamydial infections. We also observed that throughout C. trachomatis persistence induced by doxycycline (Dox) treatment, IL-1beta, IL-6, IL-8 and TNF-alpha expression was reduced, whereas the synthesis of IL-10 and IL-12p70 remained unchanged but not sustained. Thus, during chlamydial persistence infection evoked by treatment with Dox, none of the tested cytokines showed sustained expression.

Cell Line↗
PubMed2003

Virus load correlates inversely with the expression of cytotoxic T lymphocyte activation markers in HIV-1-infected/AIDS patients showing MHC-unrestricted CTL-mediated lysis.

Cytotoxic T lymphocytes (CTL) are key players to suppress viral load (VL) but CTL responses become compromised with progression of HIV-infection/AIDS. Some progressors develop MHC-unrestricted CTL with anti-CD4+ cytocidal activity. Immune activation status of these CTL and its significance in disease progression are unknown. To determine the relationship between VL and T cell activation, a cross-sectional study was carried out using blood samples from 13 HIV-1-infected/AIDS patients at various stages of progression and seven age-matched seronegative controls. We examined expression of HLA-DR and CD38 activation markers on purified CTL. MHC-unrestricted killing by these CTL was also evaluated against uninfected, allogeneic CD4+ T cells as well as several human cell lines. The expression of activation markers correlated inversely (rs = - 0.91, P < 0.0001) with VL of the subjects. CTL effectors of these patients killed targets expressing or lacking CD4+, independently of MHC class I recognition. Interestingly, the patients with higher VL showed an increased number of gammadeltaTCR-bearing CTL in blood and their MHC-unrestricted killing activity was blocked significantly (P < 0.01) by gammadeltaTCR-specific monoclonal antibody. CD3+ T counts of these patients were also consistently subnormal. Inverse correlation between VL and CD8+ T cell activation markers seems to be an indicator of CTL-associated immunopathogenesis in HIV patients with elevated gammadeltaCTL in the peripheral blood.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[In vitro inhibition of Chlamydia trachomatis growth by liposome-encapsulated cyclines].

The antichlamydial activity of tetracycline (Tet) and doxycycline (Dox) encapsulated in cationic (CaL), anionic (AnL) and neutral (NtL) liposomes has been evaluated in vitro by adding serial dilutions of antibiotics (minimum inhibitory concentration, MIC: 0.12-0.007 microgram/ml; MBC: 4 to 0.25 micrograms/ml) to HeLa 229 cell monolayers inoculated with Chlamydia trachomatis L2/434/Bu (10(3) ufi/ml). Following 72 h incubation at 37 degrees C under a 5% CO2 atmosphere, the chlamydial inclusions were stained by the May-Giemsa method to determine the MICs. After a second and third passage, the MBC1 and MBC2 were determined in antibiotic-free medium. The chlamydial inclusions were then counted to assess the degree of growth inhibition at each antibiotic dilution tested for MBC1 and MBC2 determinations. The MIC, MBC1 and MBC2 of the various antichlamydial agents were as follows: Tet (0.12; 4; 4), AnL-Tet (0.01; 1; 1), NtL-Tet (0.03; 1; 2), Dox (0.06; 1; 2), CaL-Dox (0.03; 0.5; 2), AnL-Dox (0.01; 1; 2), and NtL-Dox (0.03; 0.5; 0.5). It was found that Tet and Dox liposome-encapsulated antibiotics were more active than their non-encapsulated counterparts, and the inclusion count showed a higher inhibitory activity of the former antibiotics on chlamydial growth. The inhibition of chlamydial growth by AnL-Tet may be of bactericidal nature. In conclusion, liposome-encapsulated drugs could be of value in the treatment of chlamydial infections.

Anti-Bacterial Agents↗
PubMed2001

Evidence for a correlation between antibody-dependent cellular cytotoxicity-mediating anti-HIV-1 antibodies and prognostic predictors of HIV infection.

Using our gp120/41-expressing, NK cell activity-resistant CEM.NKR cell clones as targets in HIV-1-specific antibody-dependent cellular cytotoxicity (ADCC) assays, we demonstrate here that the serum titers of anti-HIV-1 ADCC antibodies bear a significant (P < 0.05) positive correlation with the peripheral blood CD4+ T cell counts and a negative one with the number of copies of HIV-1 RNA in the plasma of HIV-infected individuals. These findings underscore the importance of these antibodies as a protective immune parameter in these infections.

Antibody-Dependent Cell Cytotoxicity↗
PubMed2001

Effects of cationic liposome-encapsulated doxycycline on experimental Chlamydia trachomatis genital infection in mice.

In a previous study, we demonstrated that cationic liposome-encapsulated doxycycline (CaL-Dox) was two-fold more effective than free doxycycline against Chlamydia trachomatis in vitro. Here, we evaluated the effects of two CaL-Dox regimens in comparison with unencapsulated doxycycline on the course of chlamydial genital infection in mice. Progesterone-treated, female CF-1 mice were challenged intravaginally with 1.2 x 10(5) inclusion-forming units (ifu) of C. trachomatis. Two days post-infection, the animals were divided into four treatment groups for im injection of doxycycline at 10 mg/kg body weight bd for 3 (3 Dox) or 7 days (7 Dox), or of CaL-Dox at the same dose level for 3 (3 CaL-Dox) or 7 days (7 CaL-Dox) consecutively. An infected fifth group served as a control and was given an empty CaL preparation. C. trachomatis were isolated after five blind passages from 82% of infected control mice, 61.4% of 3 Dox, 52.2% of 3 CaL-Dox, 29% of 7 Dox and 20% of 7 CaL-Dox animals. Histopathological reactions were found in various tissues of the genital tract in 79.5% of infected control mice, 80.9% of 3 Dox, 65.2% of 3 CaL-Dox, 47.1% of 7 Dox and 25.7% of 7 CaL-Dox animals. Total antichlamydial antibody titres were lower in 7 CaL-Dox mice than in all the other groups (P < 0.005). The results showed that progesterone-treated CF-1 mice are suitable for investigation of both lower and upper genital tract infection with a lymphogranuloma venereum biovar strain of C. trachomatis. Neither 7 CaL-Dox nor 3 CaL-Dox treatment was more effective than unencapsulated 7 Dox doses in the bacteriological cure of chlamydial genital infection in mice. However, 7 CaL-Dox prevented tissue damage in the genital tract significantly more than all the other regimens (P < 0.05). These results suggest that liposome-encapsulated doxycycline, particularly CaL-Dox, may have potential for the clinical treatment of chlamydial infections.

Animals↗
PubMed2001

Modulation of expression of the MHC class I-binding natural killer cell receptors, and NK activity in relation to viral load in HIV-infected/AIDS patients.

The natural killer (NK) cells play an important role in viral infections via their spontaneous cytolytic activity against virus-infected cells as well as via secreting a variety of soluble mediators. The MHC class I-binding NK receptors of these cells have emerged as the most important regulators of the effector activities of cytolytic cells (both NK and CTL). We have studied the modulation of NK activity and the expression of NK receptors in HIV-infected/AIDS patients and report here that the NK activities of the patients with the lowest plasma HIV load were minimal and vice versa, suggesting a decrease in this activity following suppression of HIV replication. Interestingly, the NK activity correlated negatively with the peripheral blood CD4+ T-cell counts of these patients. Furthermore, these patients showed decreased percentages of CD56+ cells expressing NK receptors of the immunoglobulin superfamily, whereas the percentages of CD8+ cells expressing these receptors were increased. Moreover, the expression of C-type lectin-like NK receptor-associated invariant molecule CD94 was increased on CD8+ cells in these patients as compared with HIV-seronegative controls. These changes in the expression of NK receptors were also evident within groups of these patients having different viral loads. These results show, for the first time, decreased innate immunity and changes in the expression of NK receptors on cytolytic cells in relation to viral burden in HIV-infected/AIDS patient.

Adult↗
PubMed1999

In-vitro anti-chlamydial activities of free and liposomal tetracycline and doxycycline.

The purpose of this study was to evaluate the anti-chlamydial activities in vitro of liposome-encapsulated doxycycline (Dox) and tetracycline (Tet) in comparison with free Dox and Tet. Dox and Tet encapsulated in cationic (CAL), anionic (ANL) and neutral (NTL) liposomes by sonication, were quantified by high-performance liquid chromatography. Anti-chlamydial activities were determined by addition of serial dilutions of antibiotics (MIC 0.12-0.007 mg/L; MBC 4-0.25 mg/L) to HeLa 229 cell monolayers inoculated with Chlamydia trachomatis L2/434/Bu (10(3) ifu/well). After incubation for 72 h at 37 degrees C, chlamydial inclusions were stained by the May-Grünwald Giemsa method to establish MICs. MBCs were determined in chlamydial agent-free medium after second passages. Dox-encapsulation efficiencies were 28.6 SEM 6.4% in cationic (CAL-Dox), 49.1 SEM 6.7% in anionic (ANL-Dox) and 21.0 SEM 0.8% in neutral (NTL-Dox) liposomes. Tet-encapsulation efficiencies were 3.5 SEM 0.3% in anionic (ANL-Tet) and 2.2 SEM 0.6% in neutral (NTL-Tet) liposomes; no Tet was detected in cationic (CAL-Tet) liposomes. MIC values were 0.06 mg/L for Dox, 0.12 mg/L for Tet, 0.03 mg/L for CAL-Dox, NTL-Dox and NTL-Tet, and 0.01 mg/L for ANL-Dox and ANL-Tet. MBCs were 4 mg/L for Tet, 0.5 mg/L for CAL-Dox and NTL-Dox, and 1 mg/L for Dox, ANL-Dox, ANL-Tet, NTL-Tet and NTL-Tet. For MICs, the relative increase in anti-chlamydial activity observed with liposomal formulations compared to the corresponding free antibiotic ranged from 2- to 6-fold with Dox and from 4- to 10-fold with Tet. For MBCs, the relative increases in anti-chlamydial activity were 2- and 4-fold with liposome-encapsulated Dox and Tet, respectively. Dox was better encapsulated than Tet in all liposomes. Liposome-encapsulated drugs showed greater anti-chlamydial activities than their free forms; thus, these drug formulations have potential in the treatment of chlamydial infections.

Anti-Bacterial Agents↗
PubMed1998

Dental amalgam and multiple sclerosis: a case-control study in Montreal, Canada.

BACKGROUND: The aetiology of multiple sclerosis (MS) remains poorly understood. Dental amalgams containing mercury have recently been suggested as a possible risk factor for MS. METHODS: In a case-control study conducted between 1991 and 1994, we interviewed a total of 143 MS patients and 128 controls, to obtain information on socio-demographic characteristics and the number of dental amalgams and the time since installation based on dentists' records. RESULTS: Neither the number nor the duration of exposure to amalgams supported an increased risk of MS. After adjustment for age, sex, smoking, and education those who had more than 15 fillings had an odds ratio (OR) of 2.57 (95% CI: 0.78-8.54) compared to those who had none; for individuals whose first amalgam was inserted more than 15 years prior to the study, we found an OR of 1.34 (95% CI: 0.38-4.72). CONCLUSIONS: Although a suggestive elevated risk was found for those individuals with a large number of dental amalgams, and for a long period of time, the difference between cases and controls was not statistically significant.

Adult↗
PubMed1998

Nutritional factors in the aetiology of multiple sclerosis: a case-control study in Montreal, Canada.

BACKGROUND: It has been suggested that nutrition and food patterns, particularly high consumption of animal fat and low intake of fish products, may play a role in the aetiology of multiple sclerosis (MS). METHODS: The relation between nutritional factors and MS was studied among 197 incident cases and 202 frequency matched controls in metropolitan Montreal during 1992-1995. Dietary information was collected by employing a 164-item food frequency questionnaire in a face-to-face interview. RESULTS: An inverse association was observed between high body mass index (BMI) and the risk of MS, with an odds ratio (OR) of 0.76 (95% confidence interval [CI]: 0.61-0.95), per 5-unit increase in BMI, both sexes combined. In addition, taller women showed a greater risk for MS; the OR per 10 cm increase in height was 1.58 (95% CI: 1.06-2.35). In continuous variable analyses, using the difference between the lowest and highest quartile of intake as a unit, a positive association was observed with energy and animal fat intake. The OR per 897 kcal increase was 2.03 (95% CI: 1.13-3.67) and 1.99 (95% CI: 1.12-3.54) per 33 g of animal fat intake above the baseline. A significant protective effect was observed with other nutrients, including vegetable protein, dietary fibre, cereal fibre, vitamin C, thiamin, riboflavin, calcium, and potassium. Similar trends were seen for males and females when analysed separately. With respect to specific foods (as opposed to nutrients), a higher intake of fruit juices was inversely associated with risk (OR = 0.82; 95% CI: 0.74-0.92). A protective effect was also observed with cereal/breads intake for all cases combined (OR = 0.62; 95% CI: 0.40-0.97) and for fish among women only; pork/hot dogs (OR = 1.24; 95% CI: 1.02-1.51) and sweets/candy (OR = 1.29; 95% CI: 1.07-1.55) were positively associated with risk. CONCLUSION: The study generally supports a protective role for components commonly found in plants (fruit/vegetables and grains) and an increased risk with high energy and animal food intake.

Adult↗
PubMed1998

Incorporation rates, stabilities, cytotoxicities and release of liposomal tetracycline and doxycycline in human serum.

Tetracycline and doxycycline were encapsulated in cationic, anionic and neutral liposomes. The amounts of antibiotic encapsulated, the stability of each preparation at 4 degrees C for 4 weeks, and the kinetics of the release of entrapped drug into human sera were assessed by high-performance liquid chromatography. The toxicities of the liposome preparations on human erythrocytes and HeLa 229 cells were evaluated in vitro. The results showed that doxycycline was entrapped more efficiently than tetracycline, and that doxycycline-entrapped liposomes were more stable at 4 degrees C and in human sera, and less cytotoxic than tetracycline-entrapped liposomes.

Anti-Bacterial Agents↗
PubMed1994

Rapid method for isolating detergent-insoluble outer membrane proteins from Pseudomonas aeruginosa.

The present study compares two techniques for isolating outer membrane proteins (OMPs) of Pseudomonas aeruginosa, Method A - selective solubilization with sodium lauryl sarcosinate, and Method B - isopycnic sucrose gradient centrifugation, using three criteria: the amount of proteins obtained, polypeptide patterns after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their practical aspects. Method A appears to be superior to Method B. It yields a higher outer membrane protein content and a similar polypeptide pattern as Method B, but is more rapid and less cumbersome.

Bacterial Outer Membrane Proteins↗
PubMed1994

Analysis of long-term viral expression in CEM cells persistently infected with non syncytium-inducing HIV-1 strains.

CEM cells were infected with three HIV-1 non syncytium-inducing (NSI) strains obtained from AIDS patients or seropositive individuals. The surviving cells were followed for several months in the persistently infected cultures designated 65870/CEM, 65871/CEM and 3929/CEM, and analyzed for virus expression using light and electron microscopy, immunofluorescence, reverse transcriptase assay, polymerase chain reaction amplification (PCR), nucleic acid hybridization and flow cytometry. The virus isolates induced relatively few syncytia and other cytopathic effects in the corresponding cell lines and the number of cells positive for virus expression never rose above 44%. Distinct peaks of antigen-positive cells were obtained, coincident with high levels of reverse transcriptase activity. The cultures were strongly resistant to superinfection by laboratory strain Lai, with the exception of 65870/CEM which expressed HIV antigens in up to 15% of the cells for a few days. However, cell lysis was minimal in all cases. After long-term cultivation of the three cultures, no antigen-positive cells were detected and no trace of virus expression could be observed. The remaining cells consisted entirely of CD4-negative cells. PCR analyses indicated that cells harboring a provirus were progressively eliminated from the cultures, leaving only virus-free cells. In this system, cells carrying a latent provirus survive for a limited period of time before virus activation induces cell lysis. These results suggest that at least three types of cells exist in the CEM cell line: CD4-positive cells which are rapidly killed by the virus, a second type harboring a latent viral genome after the infection and which grow normally until activation of the resident genome by external or internal signal(s), and a third type which represents rare CD4-negative cells present in the initial CEM population and which are selected for by the NSI isolates. This is the first study documenting specific interactions between NSI strains of HIV-1 and distinct subpopulations of CEM cells grown as a single cell culture.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Evidence for a defect of antibody-dependent cellular cytotoxic (ADCC) effector function and anti-HIV gp120/41-specific ADCC-mediating antibody titres in HIV-infected individuals.

Antibody-dependent cellular cytotoxicity (ADCC) is an important antiviral effector mechanism. However, its role, as well as the functional integrity of the ADCC-effector cells in HIV infections, is not well understood. For studying gp120/41-specific ADCC, we recently developed a virus-free target cell system, using a natural killer (NK) cell activity-resistant human lymphoid cell line of B lineage, which was transfected with the env gene of the human immunodeficiency virus type 1 (HIV-1); gp120/41-expressing cell clones were thus selected. In this study, these gp120/41-expressing cloned cells were used as targets in a gp120/41-specific ADCC assay for (a) examining the functional integrity of ADCC-effector cells from HIV-seropositive individuals, and (b) titrating the sera of these individuals for gp120/41-specific, ADCC-mediating antibodies. Our data indicate for the first time that the percentage of sera positive for ADCC-mediating antibodies to gp120/41 is higher in individuals with CD4 counts < or = 400 and > or = 200/mm3. The individuals with CD4 counts < 200/mm3 were found to have the lowest titers of these antibodies in their sera. The ADCC-effector function of the peripheral blood mononuclear cells (PBMC) of HIV-infected individuals was significantly (p < 0.05) reduced as compared to the PBMC from healthy, HIV-seronegative individuals. Further, human recombinant IL2 and interferon-gamma were found to exert a significant (p < 0.05) enhancing effect on ADCC mediated by PBMC from these HIV-infected individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1993

Efficient entrapment of amikacin and teicoplanin in liposomes.

A higher encapsulation rate was obtained using the dehydration-rehydration method compared with the reverse-phase evaporation technique in negative multilamellar vesicles with amikacin (AMK) (45% versus 15%; P < 0.05) and teicoplanin (TCP) (34% versus 25%; P < 0.05). The addition of 250 mM sucrose to AMK- or TCP-containing liposomes without prior drying prevented a significant decrease in antibiotic content in unilamellar and multilamellar vesicles over a 3-month period at -70 degrees C.

Amikacin↗
PubMed1992

[The sexual needs of homosexual HIV seropositive men].

A two-step study was conducted to identify the sexual needs of a group of seropositive homosexual men. At first, there was an interview with 30 men which aimed to define their objectives of sexual health. This was followed by a questionnaire distributed among 88 seropositive men and 173 seronegative men, who evaluated the objectives stated in the first step. The statistical analysis of collected data allowed for the identification and narrowing down of four major needs: being in good health, being in love, being sexual and, to a lesser degree, being secure. Results are discussed and point to the role played by the biological, psychological and sociological uneasiness in the context of the difficulties that seropositive homosexual men have in satisfying their sexual needs. This evaluation can prove useful in the planning and the implementation of sexological services for HIV-positive persons.

Adaptation, Psychological↗
PubMed1991

The role of laparoscopy in acute pelvic infections.

54 patients presented by history, physical examination and laboratory tests with suspected pelvic inflammatory disease (PID). The use of laparoscopy as a diagnostic tool proved in 13 cases (24%) that the presumptive diagnosis was incorrect. Bacteriological studies revealed chlamydial infection in 21 of 41 cases, in 6 cases only at laparoscopy in the pelvic cavity, gonococcal in 9 of 41 cases; mycoplasmas were identified in 15 cases, being the only pathogen in 7. In 9 cases, no recognized pathogens were isolated. Polymicrobism was frequent. Follow-up studies identified 5 cases of treatment failure; 2 of Gonococcus and 3 of Chlamydia, and detected 3 cases of Chlamydia which had not been identified initially. We discuss the use of laparoscopy in the diagnosis and for follow-up and treatment of PIDs.

Acute Disease↗